Redispersible polymer and production process thereof

BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to (co)polymer particles having a function to be substantially redispersible in water of pH 5 or higher and also to a process for the production of the (co)polymer particles.
b) Description of the Related Art
An aqueous emulsion available by emulsion polymerization generally contains as much as 30 to 90 wt. % of water as a dispersion medium. This means that upon its piping or shipping, a great deal of water has to be transported, thereby causing a problem from the standpoint of both energy and cost.
On the other hand, a redispersible polymer is, in contrast to general aqueous emulsions, in the form of a solid or paste which is either completely or substantially free of water, and permits easy piping, shipping and storage. As another characteristic feature, a redispersible polymer can be reconstituted into an emulsified form similar to an ordinary aqueous emulsion by dissolving it in water when needed.
A redispersible polymer or a powder thereof can be premixed with another powder such as cement, gypsum or a pigment in accordance with a desired formula and can hence be provided as a one-pack product.
One-pack products with a redispersible polymer or a powder thereof premixed therein are widely used in the field of cement modifiers.
Such one-pack products with a redispersible polymer or a powder thereof premixed therein are in the form of compact light-weight powders during their piping, shipping and storage but upon use, mixing of such powders with water at construction sites makes it possible to prepare desired concretes in a single-step operation for immediate use.
Upon mixing a polymer, irksome procedures such as measuring operations can be significantly omitted so that the efficiency of work becomes extremely good. This is substantially meritorious.
Gallon cans or drum cans are needed in the case of a conventional aqueous emulsion. They are however no longer needed in the case of a redispersible polymer of a powder thereof. This is advantageous in that packaging cost can be reduced at the time of shipping and packaging materials, such as gallon cans and drum cans, to be disposed can be substantially reduced in quantity.
When provided as a premixed one-pack product, the quality control of concrete at the time of construction is made easier and the reliability of the construction is improved further, because its components have been precisely measured beforehand in accordance with a desired formula.
Compared with conventional aqueous emulsions, the redispersible polymer or its powder according to the present invention is therefore advantageous at least for the following reasons:
(1) It is possible to reduce the cost and energy required for piping, shipping or storage.
(2) The packaging cost can be reduced as large liquid containers are no longer needed.
(3) Industrial waste can be reduced since large liquid container are no longer needed.
(4) When provided in the form of a premixed one-pack product, measuring operation at a construction site is practically obviated so that substantial labor savings can be achieved.
(5) When provided in the form of a premixed one-pack product, mixing of the powder with water makes it possible to prepare desired concrete in a single step, thereby attaining substantial labor savings.
(6) When provided in the form of a premixed one-pack product, the quality control of concrete can be facilitated at the time of construction because each component has been precisely measured in accordance with a desired formula.
Nevertheless, redispersible polymers produced by conventional techniques are accompanied by at least the following disadvantages because they use conventional spray drying:
(1) Their redispersibility is not sufficient, because particles thermally cohere with one another under heat in conventional spray drying.
(2) Conventional spray drying requires a large facility and consumes a great deal of energy, and therefore is disadvantageous in cost.
A. Conventional Techniques for Polymer Particles
Conventional techniques for polymer particles will be described below. Polymer particles produced by such conventional techniques show either no redispersibility or dispersibility which is not fully satisfactory. Further, the below-described conventional techniques for the provision of polymer particles which show redispersibility all employ conventional spray drying and due to one or more drawbacks inherent to the conventional spray drying, they are unable to provide sufficient redispersibility.
Japanese Patent Laid-Open No. 193903/1984
Japanese Patent Laid-Open No. 193903/1984 in the name of TOSOH CORPORATION discloses a technique for readily obtaining an aggregate-free powder composition by polymerizing one or more unsaturated monomers in the presence of a special water-soluble copolymer which acts as a stabilizer or powdering agent across a particular pH value.
Described specifically, this technique is a production process in which, after a stable emulsion is polymerized in the presence of a water-soluble copolymer of methacrylamide and an unsaturated carboxylic acid, the resultant polymer is separated at pH 4 or lower, followed by dehydration and drying.
However, insofar as its disclosure is concerned, the process is understood to have the following inventive features.
In the invention disclosed in Japanese Patent Laid-Open No. 193903/1984, the water-soluble copolymer has the following two functions:
(1) a function as a stabilizer for stably performing the emulsion polymerization; and
(2) a function as a powdering agent for obtaining an aggregate-free powder.
This technique makes it possible to obtain an aggregate-free powder by conducting emulsion polymerization in the presence of a water-soluble copolymer having a function as a stabilizer.
Namely, a radically-polymerizable, unsaturated-bond-containing monomer (e.g., styrene) (A) is first polymerized at pH 5 or higher in an aqueous medium in the presence of a water-soluble copolymer (B) of methacrylamide and an unsaturated carboxylic acid (preferably, methacrylic acid or itaconic acid), thereby obtaining an emulsion which is stable under the action of the component (B) as a stabilizer. The pH is then adjusted to 4 or lower to separate the resultant polymer from the emulsion under the action of the component (B) as a powdering agent. The thus-separated polymer is dehydrated and dried, whereby a powder composition is obtained.
Concerning the weight ratio of the radically-polymerizable, unsaturated-bond-containing monomer (A) to the water-soluble copolymer (B), it is preferred to use (B) in an amount of from 1 to 10 parts by weight per 100 parts by weight of (A). It is described that an amount of (B) smaller than 1 part by weight cannot exhibit sufficient powdering effect for the emulsion while an amount of (B) greater than 10 parts by weight leads to an increase in production cost and is hence not needed. As a matter of fact, (B) was used in an amount of 2 parts by weight per 100 parts by weight of (A) in Examples 7 to 9.
It is also disclosed that, when methacrylic acid or itaconic acid is used as an unsaturated carboxylic acid monomer upon production of a water-soluble copolymer, the resulting water-soluble copolymer has a function as a powdering agent at a composition ratio of methacrylic acid or itaconic acid to methacrylamide in a range of from 9/1 to 1/9. Further, as a method for lowering the pH, it is disclosed to add hydrochloric acid or the like under stirring.
The theme dealt with by the technique of this publication is limited to powdering of a polymer, so that redispersion of the polymer so powdered is not contemplated at all. The powdered polymers disclosed in this publication therefore has no inherent redispersibility.
Japanese Patent Publication No. 54973/1991
Japanese Patent Publication No. 54973/1991 in the name of Wacker-Chemie GMBH discloses a technique for producing dispersible powder having excellent flowability and good redispersibility by subjecting one or more ethylenically unsaturated compounds to emulsion polymerization in the presence of a specific protective colloid and a free-radical initiator and then drying the resultant polymer.
Described specifically, in an aqueous medium containing 5 wt. % or more of a protective colloid--which is selected from a water-soluble starch having an amylose content of 30 wt. % or less, a water-swellable starch, a dispersible starch, a cyanoalkylated, hydroxyalkylated or carboxylated starch or a water-soluble protein--and a free-radical initiator (e.g., isopropyl hydroperoxide), one or more copolymerizable, ethylenically unsaturated compounds are subjected to emulsion (co)polymerization, whereby an aqueous dispersion having a water content of from 10 to 75 wt. % is obtained.
This aqueous dispersion is next subjected to spray drying optionally after adding a detackifier (e.g., PVA) and/or an atomizing aid (e.g., dextrin) in an amount of 0 to 40 wt. % as needed.
Japanese Patent Laid-Open No. 210336/1991
Japanese Patent Laid-Open No. 210336/1991 in the name of Nippon Paint Co., Ltd. discloses a technique for obtaining crosslinked resin particles from a resin
Japanese Patent Publication No. 59324/1992
Japanese Patent Publication No. 59324/1992 in the name of BASF AG discloses a process for producing a polymer powder permitting storage at room temperature and having stick-free property and water redispersibility by spray drying an aqueous dispersion which contains a vinylpyrrolidone-vinyl acetate copolymer or a water-soluble alkali (or alkaline earth) metal salt of a naphthalenesulfonic acid-formaldehyde condensation product.
Described specifically, an aqueous dispersion of a polymer is spray-dried after adding, as a water-soluble polymer substance, a copolymer (A) obtained from 20-70 wt. % of vinylpyrrolidone and 30-80 wt. % of vinyl acetate and/or a water-soluble alkali metal salt or alkaline earth metal salt (B) of a naphthalene-sulfonic acid-formaldehyde condensation product in an amount of from 2 to 40 wt. % based on the polymer in the dispersion.
The redispersible polymer powder obtained in the above-described manner is suited as an additive especially for a hydraulic binder, for example, gypsum, cement, mortar and magnesia cement.
Japanese Patent Laid-Open No. 194681/1993
Japanese Patent Laid-Open No. 194681/1993 in the having a glass transition point of 0.degree. C. or lower by a particular post-emulsification method, which comprises subjecting the resin to the post-emulsification method after addition of specific plural substances to the resin, thereby obtaining crosslinked resin particles free from interparticulate cohesion and excellent in redispersibility and storage stability.
Described specifically, the technique is a process for obtaining crosslinked resin particles by post emulsification, which comprises the following steps: dispersing a resin component in water from a resin having a glass transition point (Tg) of 0.degree. C. or lower, for example, an elastomer such as acrylic rubber, polybutadiene, polyisoprene, chloroprene, poly (.epsilon.-caprolactone) or poly(tetramethylene glycol), forming an interior of each dispersed particle into a three-dimensional structure and then removing the aqueous medium. The process features that the resin component is subjected to the post emulsification after the resin component is added with a monomer (e.g., styrene) capable of affording a resin having a Tg 20.degree. C. higher in the polymerized form than the resin component and or a resin (e.g., PS) having a Tg 20.degree. C. higher than the resin component and also with a polyfunctional vinyl compound (e.g., neopentyl glycol methacrylate). name of Rohm & Haas Co. discloses a technique, which relates to a process for producing a novel redispersible core-shell polymer powder effective as a mortar modifier.
Namely, disclosed is a redispersible polymer powder obtained by spray-drying a core-shell polymer which has been produced by polymerizing cores in the presence of alkali-soluble shells and which is formed of cores and shells chemically grafted together owing to the use of a polyfunctional compound.
Described more specifically, disclosed is a redispersible polymer powder produced from a core-shell polymer which has shells made of an alkali-soluble emulsion polymer and cores made of a water-insoluble emulsion polymer, the polymer of each of said shells and the polymer of its corresponding core having been chemically graft-bonded together by the use of a polyfunctional compound. This core-shell polymer is produced by a two-step successive emulsion polymerization process, that is, by polymerizing cores of an alkali-insoluble emulsion polymer in the presence of an emulsion polymer which has been solubilized with an alkali. Use of the core-shell polymer powder of this invention as a cement modifier has been confirmed to improve physical properties of the powder and hence to provide cement mortar having improved properties.
Japanese Language Laid-Open Publication (PCT) No. 501575/1993
Japanese Language Laid-Open Publication (PCT) No. 501575/1993 in the name of Henkel KG Auf Aktien) discloses a process for the production of a stable polymer dispersion by employing as a stabilizer an amphoteric polymer which has excellent shear stability and water-proofness and is useful inter alia as a finish for textile products. The amphoteric polymer is obtained by adjusting the pH of an aqueous solution of a stabilizer composed of a starting amphoteric polymer to an isoelectric point with an acid or the like to cause the starting amphoteric polymer to precipitate from the aqueous solution, adjusting the pH of the aqueous solution to redissolve the precipitate, adding a catalyst and the like and then conducting emulsion polymerization.
Described specifically, the pH of an aqueous solution of a stabilizer composed of a starting amphoteric polymer is adjusted to an isoelectric point with a non-volatile acid or base to cause the starting amphoteric polymer to precipitate. Using a volatile base or acid, the pH of the solution is adjusted to a value desirable for emulsion polymerization, so that the precipitate is redissolved. Thereafter, an unsaturated monomer of the vinyl structure is neutralized with a non-volatile neutralizing agent and is added together with a catalyst and one or more optional aids, followed by emulsion polymerization so that the target dispersion is obtained.
B. Conventional Techniques on Protective Colloid Polymerization
Protective colloid polymerization is a polymerization process which is known to the public and is used publicly.
The concepts of the terms "protective colloid polymerization" and "protective colloid" as well as the concept and principle of protective colloid polymerization are disclosed in introductory textbooks, for example, Tsunetaka Matsumoto: "Kogyo Zairyo (Industrial Material), Emarushion Gairon (Introduction to Emulsion)", 24(3), 10-15.
In particular, visual and readily-understandable explanations are found in "FIG. 2 Shinsuisei Monoma no Nyuka Jyugo (Emulsion Polymerization of Hydrophilic Monomers" (page 12) and its description [under "Shinsuisei Monoma no Nyuka Jyugo (Emulsion Polymerization of Hydrophilic Monomers" on page 12] and further in "FIG. 3 Mizu Emarushion no Anteika (Stabilization of Aqueous Emulsion)" (page 13) and its description [under "Mizu Emarushion no Anteika (Stabilization of Aqueous Emulsion)" on pages 12-13].
Unless otherwise specifically indicated, all publications and parts thereof cited herein are incorporated herein by reference so that matters directly and conceivable by a person having ordinary knowledge in the present field of art based on the matters disclosed herein with reference to such cited parts shall be construed as being disclosed herein.
Illustrative of specific examples of known techniques on protective colloid polymerization are those disclosed in Japanese Patent Laid-Open Nos. 173003/1990 and 185607/1992, which will be described hereinafter.
Japanese Patent Laid-Open No. 185607/1992
Japanese Patent Laid-Open No. 185607/1992 in the name of Hoechst Gosei K. K. discloses an invention on a redispersible acrylic resin emulsion powder of the protective colloid type and its production process. Namely, an acrylic monomer is subjected to emulsion (co)polymerization in the presence of a specific amount of a chain transfer agent while using a water-soluble protective colloid. The resulting emulsion is spray-dried, whereby the above-described powder excellent in redispersibility, film properties and the like is obtained. Described specifically, using a water-soluble protective colloid (e.g., polyvinyl alcohol), an acrylic monomer (e.g., methyl methacrylate) is subjected to emulsion polymerization in the presence of a chain transfer agent (e.g., trichloroethylene) in an amount of from 0.1 to 50 wt. % on the basic of the acrylic monomer, optionally together with 30 wt. % or less of a copolymerizable monomer (e.g., styrene). The resulting acrylic resin emulsion is then spray-dried, so that a redispersible acrylic resin emulsion of the protective colloid type is obtained. The resin emulsion powder so obtained is suitably usable as an adhesive, a paint binder, a cement additive and the like.
Japanese Patent Laid-Open No. 173003/1990
Japanese Patent Laid-Open No. 173003/1990 in the name of Mitsui-Toatsu Chemicals Inc. discloses a technique for efficiently obtaining porous polymer particles without inclusion of impurities such as a dispersant, a diluent and the like by dispersing an oil phase, which contains a polymerizable monomer and a diluent, in an aqueous medium containing a dispersant and then polymerizing the resultant dispersion under specific conditions.
Described specifically, in an aqueous medium (b) containing 0.1-10 wt. % of a dispersant (a) which is a partially-saponified PVA having a saponification degree of 50-95%, an oil phase (e) containing a polymerizable monomer (c), which is a monomer insoluble or sparingly soluble in the component (b) and contains a vinyl group, and a diluent (d) which is soluble in the component (c) but insoluble or sparingly soluble in the component (b) and has no polymerizability is dispersed in the form of spheres of 1-50 .mu.m in diameter at a volume ratio of the component (b) to the component (c) in an range of from 10:1 to 1:1. While polymerizing the component (c), the dispersed particles are caused, in their spherical forms, to flocculate into sizes of from 0.1 to 3 mm in diameter so that a polymer particle flocculate is obtained. This flocculate is then washed to remove the component (a). Subsequent to extraction of the component (d), the flocculate is redispersed to sizes of from 1 to 5 .mu.m.
C. Technical Background Concerning Redispersibility and Film-Forming Properties
Redispersibility and Film-Forming Properties
Redispersible polymers or their powders include those incapable of forming films at room temperature when reconstituted to redispersions. To be usable for a wide range of applications, a redispersible polymer or a powder thereof whose reconstituted redispersion dries at room temperature into a film is however preferred. When an aqueous emulsion such as that capable of forming a film at room temperature is dried, a serious problem arises, that is, the polymer is so soft that dispersed particles of the polymer undergo aggregation and cohesion and the redispersibility is lost.
Anti-Binding Agent
To avoid mutual aggregation and cohesion of powder particles, it is known to add as an anti-binding agent a fine inorganic powder or a fine organic powder having no binding ability.
Such a method however involves a problem in that, when a film is formed by drying a redispersion, undesirous effects are given to various properties such as transparency. This has imposed a considerable limitation on the utility and application field.
Among applications of a redispersible polymer or its powder, a cement additive is expected to develop less problems even when fine inorganic power is mixed. Even in the case of such a cement additive, an increase in flow value is observed due to large hygroscopicity of the fine inorganic powder, thereby making it necessary to increase the water/cement ratio.
Further problems have also been observed, including production of cement products having high hygroscopicity and also production of cement products prone to dusting of fine powder and hence to non-uniformity in composition.
For such problems, it has been desired to develop a redispersible polymer which does not require such an anti-binding agent.
Core-Shell Polymers Having Alkali-Soluble Shells
Among the conventional techniques on redispersible polymer powders, the method making use of a core-shell polymer equipped with alkali-soluble shells is accompanied by a problem in redispersibility because the shells have a low density due to their solubility and are unable to completely prevent cohesion of particles during drying.
Moreover, omission of an anti-binding agent results in a new problem that the cohesion of particles cannot be prevented.
Spray Drying Technique
Most redispersible polymer powders are produced by spray drying, which directly obtains powder by causing water to evaporate while preventing aggregation.
Conventional spray drying however involves a problem in redispersibility, because powder is dried usually at a temperature as high as 100.degree. C. or higher and cohesion of particles cannot be prevented completely.
In some instances, a deposit or the like occurs on an inner wall of a drying tower upon spray drying, leading to a substantial reduction in yield.
A further serious problem is also involved in that enormous time and energy are needed in large-scale production or batchwise production.
The present inventors considered that the conventional techniques for the production of a redispersible polymer or its powder are not satisfactory for the need for such enormous time and energy.
D. Technical Background Concerning Cement Additives
Dai 50 Kai Semento Gijyutsu Taikai Koen Yoshishu (Abstracts of Lectures at the 50th Cement Technology Symposium), 324-325, 1996
A polymer cement mortar with a redispersible powder resin mixed therein is described to still involve an unsolved technical problem in redispersibility or the like and to result in lowered compression strength and/or flexural strength in some instances.
Dai 50 Kai Semento Gijyutsu Taikai Koen Yoshishu (Abstracts of Lectures at the 50th Cement Technology Symposium), 322-323, 1996
A polymer cement mortar with a redispersible powder resin mixed therein is described to have tendency to permit introduction of air into cement so that in some instances, the compression strength and/or flexural strength may be reduced to adversely affect various physical properties.
In view of the above-described teachings, development of a redispersible powder resin excellent in redispersibility, if succeeded, is expected to provide polymer cement mortar with improved physical properties because such a redispersible powder resin makes it possible to complete the mixing of water, cement, sand and the like in a short time and hence to reduce the amount of air to be introduced into cement.
SUMMARY OF THE INVENTION
In view of the above-described problems of the conventional techniques, the present inventors found it to be an extremely meaningful theme to provide a high-quality redispersible polymer product of the piping-cost saving, transportation-cost saving and waste-material reducing type by an efficient production process of the energy saving, labor saving, space saving and process simplifying type totally different from the conventional redispersible-polymer production techniques which require enormous time and energy (for example, those making use of spray drying or the like).
Namely, the following themes (1) and (2) were sought for achievement in the present invention.
(1) Powdering of a polymer: this is a theme to cause precipitation of (co)polymer particles in a polymer emulsion without aggregation.
(2) Redispersion of a powdered polymer: this is a theme to provide the (co)polymer particles, which has been converted into powder as described above under (1), with a function to be substantially redispersible in water of pH 5 or higher.
Such unique recognitions of the present inventors have been scarcely acknowledged by artisans to date.
Accordingly, the "themes sought for achievement by the invention" which served as a basis for the completion of the present invention have themselves novelty and unobviousness, to say nothing of the possession of novelty and unobviousness by the present invention.
As a result of an extensive investigation, the present inventors have found that an aqueous emulsion available by the polymerization of an ethylenically unsaturated monomer in the presence of a protective colloid under specific conditions forms a flocculate by the addition of an acid or a metal salt and moreover, this flocculate surprisingly has a function to be substantially redispersible in water of pH 5 or higher, leading to the completion of the present invention. The present invention therefore provides the following (co)polymers, and their production processes and compositions:
(1) A (co)polymer formed of particles and having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said particles have a core/shell structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a (co)polymer (.alpha.2) composed of a recurring unit and 0 wt. % or more but less than 40 wt. % of at least one recurring unit selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR1## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms;
said shell is made of a (co)polymer (.alpha.1) composed of a recurring unit and 20 wt. % or more but not greater than 100 wt. % of at least one recurring unit selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) in (.alpha.1) is contained at a higher content than said at least one recurring unit in (.alpha.2).
(2) A (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said (co)polymer is a mixture of particles (A) and a protective colloid;
said particles (A) are made of a (co)polymer (.alpha.2) composed of a recurring unit and 0 wt. % or more but less than 40 wt. % of at least one recurring unit selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR2## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms;
said protective colloid is made of a (co)polymer (.alpha.1) composed of a recurring unit and 20 wt. % or more but not greater than 100 wt. % of at least one recurring unit selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) in (.alpha.1) is contained at a higher content than said at least one recurring unit in (.alpha.2).
(3) A (co)polymer as described above under the item (1) or (2), wherein of said recurring units making up each of (.alpha.1) and (.alpha.2), the recurring unit other than said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) is composed of at least one of the following structural units (v) to (z): ##STR3## wherein R.sup.11 represents a hydrogen atom or a methyl group, R.sup.12 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms, R.sup.13 represents a hydrogen atom, an alkyl group having 1-20 carbon atoms, an alkenyl group having 1-20 carbon atoms or a phenyl group, R.sup.14 s are the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, a sulfonic group or a metal sulfonate group, and R.sup.15 represents a divalent hydrocarbon group having 1-6 carbon atoms.
(4) A (co)polymer as described above under any one of the items (1) to (3), wherein (.alpha.1) comprises 20 wt. % or more but not greater than 100 wt. % of at least one recurring unit selected from the group consisting of said recurring units having said pendant groups represented by the following formula (2): ##STR4## wherein R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms.
(5) A (co)polymer as described above under item (4), wherein said at least one recurring unit having said pendant group represented by the formula (2) has been derived from 2-hydroxyethyl methacrylate.
DESCRIPTION OF THE PREFERPED EMBODIMENTS
Specific processes for the production of the above-described (co)polymers include:
(6) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (aqueous emulsion preparation step), subjecting a reaction mixture, which comprises:
a protective colloid (.alpha.1) obtained by radical (co)polymerization of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the formula (2): ##STR5## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, and
an ethylenically unsaturated monomer for forming a copolymer (a2), said ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2),
to radical (co)polymerization so that based on the total weight of (a1) and (a2), (a1) ranges from 15 to 85 wt. % while (a2) ranges from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2), whereby an aqueous emulsion formed of a dispersed phase of (co)polymer particles (A) and a continuous phase of water is prepared; and
as step 2 (flocculate forming step),
adding a mineral acid and/or an organic acid to said aqueous emulsion, which has been prepared in step 1, to adjust the pH of said aqueous emulsion to 4 or lower, whereby said (co)polymer particles (A) are caused to flocculate and a flocculate (A') of said (co)polymer is formed.
(7) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (core particle polymerization step),
emulsion (co)polymerizing, into a (co)polymer (a2), an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (2): ##STR6## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, whereby an aqueous emulsion formed of a dispersed phase of (co)polymer core particles (A.degree.) and a continuous phase of water is prepared;
as step 2 (shell polymerization step), subjecting a reaction mixture, which comprises:
said (co)polymer core particles (A') in said aqueous emulsion prepared in step 1, and an ethylenically unsaturated monomer for forming a copolymer (a1), said ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2),
to radical (co)polymerization so that based on the total weight of (a1) and (a2), (al) ranges from 15 to 85 wt. % while (a2) ranges from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2), whereby shells (S) made of a protective colloid are formed on at least parts of surfaces of said (co)polymer core particles (A.degree.) in said aqueous emulsion prepared in step 1 and an aqueous emulsion formed of a dispersed phase of core/shell (co)polymer particles (A) having a core/shell structure with at least a part of a surface of each core being covered with an associated shell and a continuous phase of water is prepared; and
as step 3 (flocculate forming step),
adding a mineral acid and/or an organic acid to said aqueous emulsion, which has been prepared in step 2, to adjust the pH of said aqueous emulsion to 4 or lower, whereby said core/shell (co)polymer particles (A) are caused to flocculate and a flocculate (A') of said (co)polymers is formed.
(8) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (aqueous emulsion preparation step),
emulsion (co polymerizing, into a (co)polymer (a2), an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (2): ##STR7## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, whereby an aqueous emulsion formed of a dispersed phase of (co)polymer core particles (A.degree.) and a continuous phase of water is prepared;
as step 2 (protective colloid preparation step),
conducting radical (co)polymerization of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2), whereby a protective colloid (a1) is prepared;
As step 3 (mixing step),
mixing said aqueous emulsion prepared in step 1 with said protective colloid prepared in step 2 so that based on the total weight of (a1) and (a2), (a1) ranging from 15 to 85 wt. % while (a2) ranging from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2); and
as step 4 (flocculate forming step),
adding a mineral acid and/or an organic acid to a mixture of said aqueous emulsion and said protective colloid, which has been obtained in step 3, to adjust the pH of said mixture to 4 or lower, whereby said (co)polymer particles (A) and said protective colloid are caused to flocculate and a flocculate (A') of said (co)polymers is formed.
(9) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (aqueous emulsion preparation step), subjecting a reaction mixture, which comprises:
a protective colloid (al) obtained by radical (co)polymerization of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the formula (2): ##STR8## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, and
an ethylenically unsaturated monomer for forming a copolymer (a2), said ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2),
to radical (co)polymerization so that based on the total weight of (a1) and (a2), (a1) ranges from 15 to 85 wt. % while (a2) ranges from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2), whereby an aqueous emulsion formed of a dispersed phase of (co)polymer particles (A) and a continuous phase of water is prepared; and
as step 2 (flocculate forming step),
adding a metal salt to said aqueous emulsion, which has been prepared in step 1, to salt out said (co)polymer particles (A), whereby a flocculate (A') of said (co)polymer is formed.
(10) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (core particle polymerization step),
emulsion (co)polymerizing, into a (co)polymer (a2) , an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (2): ##STR9## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, whereby an aqueous emulsion formed of a dispersed phase of (co)polymer core particles (A.degree.) and a continuous phase of water is prepared;
as step 2 (shell polymerization step), subjecting a reaction mixture, which comprises:
said (co)polymer core particles (A.degree.) in said aqueous emulsion prepared in step 1, and
an ethylenically unsaturated monomer for forming a copolymer (a1), said ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2),
to radical (co)polymerization so that based on the total weight of (a1) and (a2), (a1) ranges from 15 to 85 wt. % while (a2) ranges from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2), whereby shells (S) made of a protective colloid are formed on at least parts of surfaces of said (co)polymer core particles (A.degree.) in said aqueous emulsion prepared in step 1, whereby an aqueous emulsion formed of a dispersed phase of core/shell (co)polymer particles (A) having a core/shell structure with at least a part of a surface of each core being covered with an associated shell and a continuous phase of water is prepared; and
as step 3 (flocculate forming step),
adding a metal salt to said aqueous emulsion, which has been prepared in step 2, to salt out said core/shell (co)polymer particles (A), whereby a flocculate (A') of said (co)polymer is formed.
(11) A process for the production of a (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, which comprises:
as step 1 (aaueous emulsion preparation step),
emulsion (co)polymerizing, into a (co)polymer (a2), an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (2): ##STR10## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms, whereby an aqueous emulsion formed of a dispersed phase of (co)polymer core particles (A.degree.) and a continuous phase of water is prepared;
as step 2 (protective colloid preparation step),
conducting radical (co)polymerization of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (1) and the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the formula (2);
as step 3 (mixing step),
mixing said aqueous emulsion prepared in step 1 with said protective colloid prepared in step 2 so that based on the total weight of (a1) and (a2), (a1) ranges from 15 to 85 wt. % while (a2) ranges from 85 to 15 wt. % and said at least one monomer having said pendant group represented by the formula (1) and/or (2) in (a1) is contained at a higher content than said at least one monomer in (a2); and
as step 4 (flocculate forming step),
adding a metal salt to a mixture of said aqueous emulsion and said protective colloid, which has been obtained in step 3, to salt out said (co)polymer particles (A) and said protective colloid, whereby a flocculate (A') of said (co)polymer is formed.
(12) A process as described above under any one of the items (6) to (11), wherein (a1) is obtained using at least one monomer selected from the group consisting of said ethylenically unsaturated monomers having said pendant groups represented by the following formula (2): ##STR11## wherein R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms.
(13) A process as described above under item (12), wherein said at least one monomer is 2-hydroxyethyl methacrylate.
(14) A (co)polymer having a function to be substantially redispersible in water of pH 5 or higher and obtained by a process as described above under any one of the items (7) to (13).
(15) A (co)polymer substantially redispersible at pH 5 or higher, wherein:
said (co)polymer is in the form of particles having a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a water-insoluble (co)polymer; and
said shell is made of a (co)polymer water-soluble at pH 5 or higher.
(16) A (co)polymer substantially redispersible at pH 5 or higher, wherein:
said (co)polymer is in the form of particles having a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a water-insoluble (co)polymer;
said shell is made of a (co)polymer water-soluble at pH 5 or higher; and
said shells account for at least 15 wt. % of the total weight of said cores and said shells.
(17) Particles substantially free of intraparticular blocking property, wherein:
said particles have a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said cores have a glass transition point in a range of from -40 to +30.degree. C.; and
said shells have a glass transition point at least 10.degree. C. higher than said glass transition point of said cores, account for at least 15 wt. % of the total weight of said particles, and have a function to flocculate at pH 4 or lower.
(18) A hydraulic cement composition comprising 0.5-60 wt. %, based on hydraulic cement, of a (co)polymer as described above under the items (1) to (5) and (14) to (17) as calculated in a dry state.
(19) A method for the formation of a hardened cement body, which comprises mixing a hydraulic cement composition, which has been added with 0.5-60 wt. %, based on hydraulic cement, of a (co)polymer as described above under any one of the items (1) to (5) and (14) to (17) as calculated in a dry state, with water and then placing the resultant cement-water mixture.
As the flocculate according to the present invention can be readily subjected to solid-liquid separation by a simple operation such as filtration, centrifugation or decantation, it is not absolutely needed to conduct spray drying.
Another characteristic feature of such a flocculate resides in that any mixed protective colloid, free acid and other free water-soluble substances can be eliminated by washing the flocculate during and/or subsequent its solid-liquid separation.
Such a flocculant is characterized in that it has excellent anti-binding property without the need for an anti-binding agent (fine inorganic power, fine organic powder, or the like) as an essential component.
When used as a cement modifier, the redispersible (co)polymer according to the present invention improves the tensile strength, flexural strength, compression strength, bonding strength, wear resistance and the like of cement.
It is the characteristic feature of the present invention that an anti-binding agent (for example, a fine inorganic powder, a fine organic powder having no film-forming property, or the like) is not absolutely required. As applications other than the above-mentioned cement modifier, the present invention can be applied to a wide variety of fields where an aqueous emulsion is usually employed, for example, construction materials, papermaking chemicals, paints, adhesives, fiber finishes and the like.
Incidentally, no particular limitation is imposed on the form, shape and morphology of the "(co)polymer having a function to be substantially redispersible in water of pH 5 or higher" according to the present invention insofar as the "(co)polymer" has the function to be substantially redispersible in water of pH 5 or higher. In general, the redispersible (co)polymer according to the present invention is preferably in the form of powder, granules, paste, wet cake available after filtration, or beads or the like available by granulation of such powder, granules, paste or wet cake.
The present invention will hereinafter be described in detail.
A. Basic Concept
The glass transition point (Tg) of each (co)polymer described herein can be measured by a method known per se in the art, for example, by DSC or the like. In the case of a copolymer, its glass transition point is measured as will be described below.
Measured Glass Transition Point--Measurement of Glass Transition Point (Tg) of Copolymer
The glass transition point (Tg) of a copolymer is measured and evaluated as will be described below.
The glass transition point (Tg) of a copolymer having a specific monomer composition can be determined by conducting a calculation in accordance with the Fox's equation. According to the Fox's equation, the Tg of a copolymer can be calculated on the basis of the Tgs of homopolymers of individual monomers forming the copolymer. Its details are described in Bulletin of the American Physical Society, Series 2, 1(3), 123, 1956. The term "calculated glass transition point" as used herein embraces glass transition points calculated in accordance with the Fox's equation.
As the Tgs of homopolymers of various monomers based on which Tgs of copolymers can be calculated in accordance with the Fox's equation, it is possible to use, for example, the values shown on pages 525-546 of Kobunshi Data Handbook, Volume: Basic Data (compiled by The Society of Polymer Science, Japan) or values actually measured by a method known per se in the art.
Concept of the Term "Emulsion (Co)Polymerization")
The term "emulsion (co)polymerization", which is used in the aqueous emulsion preparation step of the production process according to the present invention, embraces techniques such as not only ordinary emulsion (co)polymerization but also certain special techniques [protective colloid (co)polymerization, mini-emulsion (co)polymerization and micro-emulsion (co)polymerization].
Further, a process in which a polymer is subjected to self-emulsification or forced emulsification subsequent to its mixing with a solvent and an emulsifier is also encompassed by the concept of "emulsification" as used herein.
Protective Colloid Polymerization
The concepts of the terms "protective colloid polymerization" and "protective colloid" as well as the concept and principle of protective colloid polymerization are disclosed, for example, in an introductory textbook such as Tsunetaka Matsumoto: "Kogyo Zairyo (Industrial Material), Emarushion Gairon (Introduction to Emulsion)", 24(3), 10-15.
In particular, visual and readily-understandable explanations are found in "FIG. 2 Shinsuisei Monoma no Nyuka Jyugo (Emulsion Polymerization of Hydrophilic Monomers" (page 12) and its description [under "Shinsuisei Monoma no Nyuka Jyugo (Emulsion Polymerization of Hydrophilic Monomers" on page 12] and further in "FIG. 3 Mizu Emarushion no Anteika (Stabilization of Aqueous Emulsion)" (page 13) and its description [under "Mizu Emarushion no Anteika (Stabilization of Aqueous Emulsion)" on pages 12-13).
As a typical known example of protective colloid polymerization, the technique disclosed to the above-described Japanese Patent Laid-Open No. 173003/1990 can be mentioned.
Concept of the Term "(Co)Polymer"
The concept of the term "(co)polymer" as used herein embraces both homopolymers and copolymers.
No particular limitation is imposed on the arrangement of monomer segments in each copolymer. The copolymer can therefore be a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer or the like.
The term "(co)polymer" as used herein also encompasses (co)polymers in each of which at least a part thereof has any one of linear, cyclic, macrocyclic, branched, star, three-dimensional network, IPN (interpenetrated network), PIC (polyion complex) and like structures.
Concept of the Expression "Substantially Redispersible in Water of pH 5 or Higher"
The concept of the expression "substantially redispersible in water of pH 5 or higher" as used herein means that the redispersible (co)polymer according to the present invention can show redispersibility to such an extent as not attainable by conventional spray drying. For example, it means that the value of "redispersibility (%)" as defined in Evaluation Example 1-2 to be described subsequently herein ranges from 40 to 100%, preferably from 60 to 100%, more preferably from 80 to 100%. In Evaluation Example 7-5, it is also meant that its value ranges from 20 to 100%, more preferably from 40 to 100%.
Form of Flocculate (A') of (Co)Polymer
In the present invention, a (co)polymer flocculate (A') is generally in the form of a paste containing some water in many instances.
The (co)polymer flocculate is however not limited to such a form and may also take any other form such as tablets, granules or a film.
(Co)Polymer Having a Function to be Substantially Redispersible in Water of pH 5 or Higher
No particular limitation is imposed on the form, shape and morphology of the "(co)polymer having a function to be substantially redispersible in water of pH 5 or higher" according to the present invention insofar as the "(co)polymer" has the function to be substantially redispersible in water of pH 5 or higher. In general, the redispersible (co)polymer according to the present invention is preferably in the form of powder, granules or paste.
Concept of the Term "Particles"
The concept of the term "particles" as used herein fully embraces the concept which this term generally has in high-molecular chemistry, but they are not completely equivalent to each other. The scanning electron microscopic form of "particles" as used herein includes, for example, forms having many asperities like raspberries or konpeito ("confeitos" in Portuguese), flattened forms like erythrocytes, prolate-spheroidal forms like rugger balls, and spindle-shaped forms like E. coli.
The concept of the term "particles" as used herein embraces microspheres which form, for example, polymer emulsions, latexes or polymer suspensions. In the present invention, these exemplified forms are taken in general. As is appreciated from the foregoing, the term "particles" will be used for the sake of convenience in frequently referring to certain essential "embodiments" of a heteropolymer system according to the present invention although the concept of the term "particles" as used herein is not completely equivalent to the concept which the same term generally has in high-molecular chemistry.
Particles Having Core/Shell Structure
The terms "core", "shell" and "core/shell" as used in herein fully embrace the concepts which these terms generally have in high-molecular chemistry, but they are not completely equivalent to each other. For example, concerning "core/shell" particles according to the present invention, the term "core/shell" as used herein encompasses such embodiments that a "core" is at least partly enclosed in a "shell". As is appreciated from the foregoing, the term "core", "shell" and "core/shell" will be used for the sake of convenience in frequently referring to certain essential "embodiments" of a heteropolymer system according to the present invention although the concepts of the terms "core", "shell" and "core/shell" as used herein are not completely equivalent to the concepts which these terms generally have in high-molecular chemistry.
In high-molecular chemistry, the term "core" is generally used in a sense equivalent to the term "core", "center", "nucleus", "center" or "seed". On the other hand, the term "shell" is used in a sense equivalent to the term "skin", "husk", "sheath" or "robe".
Accordingly, the term "core", "center", "nucleus", "center" or "seed" can be used interchangeably with the term "core" as used herein, and the term "skin", "husk", "sheath" or "robe" can be used interchangeably with the term "shell" as used herein.
Structure of Particles
Examples of the particle structure of the (co)polymer particles (A) as primary particles include:
(1) a structure generally called the "core/shell" type, in which the surface of the (co)polymer particle of the ethylenically unsaturated monomer (a2), said particle being contained in each particle, is fully covered with the protective colloid (a1);
(2) a structure in which the protective colloid (a1) is deposited on a part of the (co)polymer particle of the ethylenically unsaturated monomer (a2), said particle being contained in each particle, and the surface of the (co)polymer particle is not fully covered with the protective colloid; and
(3) a so-called salami structure in which the protective colloid (a1) is contained in each (co)polymer particle of the ethylenically unsaturated monomer (a2).
Morphologically, the term "particle" as used herein also embraces particles of special shapes such as hollow particles and particles of the structure that an additional particle exists in each hollow particle. Accordingly, no particular limitation is imposed on the structure of particles.
It is to be noted that the structure of particles is not limited to such exemplified structures insofar as on an outer wall of each (co)polymer particle of the ethylenically unsaturated monomer (a2), the protective colloid (al) exists in a quantity sufficient to show redispersibility.
High-Order Particles
In the present invention, when the (co)polymer particles (A) are considered to exist as primary particles, the flocculate (A') of the (co)polymer particles can be in the form of secondary particles, tertiary particles formed of plural secondary particles united together, or particles of a still higher order insofar as the flocculate conforms with the objects of the present invention. No particular limitation is therefore imposed in this respect.
In the present invention, the flocculate (A') of the (co)polymer is generally in the form of particles of the tertiary or still higher order which are formed of secondary particles obtained by cohesion of plural (co)polymer particles (A) as primary particles. When added to water or alkaline water, the flocculate is readily emulsified back into primary particles or into a form substantially resembling primary particles.
The flocculate (A') of the (co)polymer in the present invention may generally be in the form of secondary particles obtained by cohesion of plural (co)polymer particles (A) as primary particles. When added to water or alkaline water, such a flocculate is also readily emulsified back into primary particles or into a form substantially resembling primary particles.
Concept of the Term "Salting Out"
The concept of the term "salting out" as used herein embraces the concept which the same term generally has in high-molecular chemistry, but they are not completely equivalent to each other. For example, "Kagaku Daijiten (ENCYCLOPAEDIA CHIMICA)", Volume 1 (a,i,u,e), 1960 (Kyoritsu Shuppan Co., Ltd.) contains an annotation of the term "salting out" in the left-right column on page 1108, where "salting out" is described to mean "to add to an aqueous solution another substance (primarily, an inorganic salt or the like) to cause coagulation of a substance dissolved beforehand (in the aqueous solution)".
The concept of the term "salting out" as used herein fully encompasses the concept recognized in general chemistry as described in "Kagaku Daijiten (ENCYCLOPAEDIA CHIMICA)" and as will be described next, also embraces the concept which this term generally has in colloid chemistry and high-molecular chemistry.
Namely, as is described on pages 187-200 of Soichi Muroi: "Kohbunshi Ratekkusu no Kagaku (Chemistry of High-Molecular Latex)", 1980 (Kobunshi Kankokai, Inc), particles which are maintained in a uniformly-dispersed state can be caused to undergo coagulation by adding an electrolyte and hence developing a dispersion-destructing action (salting out). The concept of the term "salting out" as used herein also embraces such a phenomenon.
As is appreciated from the foregoing, the term "salting out" will be used for the sake of convenience in frequently referring to certain essential "embodiments" of the present invention although the concept of the term "salting out" as used herein is not completely equivalent to the concept which the same term generally has in general chemistry.
Illustrative of the (co)polymer according to the present invention are:
(1) A (co)polymer formed of particles and having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said particles have a core/shell structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a (co)polymer (.alpha.2) composed of a recurring unit and 0 wt. % or more but less than 40 wt. % of at least one recurring unit selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR12## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms;
said shell is made of a (co)polymer (.alpha.1) composed of a recurring unit and 20 wt. % or more but not greater than 100 wt. % of at least one recurring unit selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) in (.alpha.1) is contained at a higher content than said at least one recurring unit in (.alpha.2).
(2) A (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said (co)polymer is a mixture of particles (A) and a protective colloid;
said particles (A) are made of a (co)polymer (.alpha.2) composed of a recurring unit and 0 wt. % or more but less than 40 wt. % of at least one recurring unit selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR13## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms or R.sup.3, together with the hydroxyl group bonded thereto, represents --(R.sup.22 --O).sub.n --H in which n stands for an integer of 2 to 33 and R.sup.22 s may be the same or different and individually represents an alkylene group having 2-5 carbon atoms;
said protective colloid is made of a (co)polymer (.alpha.1) composed of a recurring unit and 20 wt. % or more but not greater than 100 wt. % of at least one recurring unit selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) in (.alpha.1) is contained at a higher content than said at least one recurring unit in (.alpha.2).
(3) A (co)polymer according to claim 1 or 2, wherein of said recurring units making up each of (.alpha.1) and (.alpha.2), the recurring unit other than said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) is composed of at least one of the following structural units (v) to (z): ##STR14## wherein R.sup.11 represents a hydrogen atom or a methyl group, R.sup.12 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms, R.sup.13 represents a hydrogen atom, an alkyl group having 1-20 carbon atoms, an alkenyl group having 1-20 carbon atoms or a phenyl group, R.sup.14 s are the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, a sulfonic group or a metal sulfonate group, and R.sup.15 represents a divalent hydrocarbon group having 1-6 carbon atoms.
The present invention also provides:
(4) A (co)polymer substantially redispersible at pH 5 or higher, wherein:
said (co)polymer is in the form of particles having a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a water-insoluble (co)polymer; and
said shell is made of a (co)polymer water-soluble at pH 5 or higher.
(5) A (co)polymer substantially redispersible at pH 5 or higher, wherein:
said (co)polymer is in the form of particles having a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said core is made of a water-insoluble (co)polymer;
said shell is made of a (co)polymer water-soluble at pH 5 or higher; and
said shells account for at least 15 wt. % of the total weight of said cores and said shells.
(6) Particles substantially free of intraparticular blocking property, wherein:
said particles have a shell/core structure with at least a part of a surface of each core being covered with an associated shell;
said cores have a glass transition point in a range of from -40 to +30.degree. C.; and
said shells have a glass transition point at least 10.degree. C. higher than said glass transition point of said cores, account for at least 15 wt. % of the total weight of said particles, and have a function to flocculate at pH 4 or lower.
The present invention typically provides a (co)polymer substantially redispersible at pH 5 or higher, which is in the form of particles having a core/shell structure with at least a part of a surface of each core covered with an associated shell, said cores and shells being specified as described above.
The followings are more specific examples of the (co)polymer according to the present invention:
(7) A (co)polymer formed of particles and having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said particles have a core/shell structure;
said core is made of a (co)polymer (.alpha.2) of an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one ethylenically unsaturated monomer selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR15## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms;
said shell is made of a (co)polymer (.alpha.1) of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one ethylenically unsaturated monomer selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one ethylenically unsaturated monomer having said pendant group represented by the formula (.alpha.1) is contained at a higher content than said at least one ethylenically unsaturated monomer in (.alpha.2).
(8) A (co)polymer having a function to be substantially redispersible in water of pH 5 or higher, wherein:
said (co)polymer is a mixture of particles (A) and a protective colloid;
said particles (A) are made of a (co)polymer (.alpha.2) of an ethylenically unsaturated monomer comprising 0 wt. % or more but less than 40 wt. % of at least one ethylenically unsaturated monomer selected from the group consisting of recurring units having pendant groups represented by the following formula (1) and the group consisting of recurring units having pendant groups represented by the following formula (2): ##STR16## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms;
said protective colloid is made of a (co)polymer (.alpha.1) of an ethylenically unsaturated monomer comprising 20 wt. % or more but not greater than 100 wt. % of at least one ethylenically unsaturated monomer selected from the group consisting of said recurring units having said pendant groups represented by the formula (1) and the group consisting of said recurring units having said pendant groups represented by the formula (2);
based on the total weight of (.alpha.1) and (.alpha.2), (.alpha.1) ranges from 15 to 85 wt. % while (.alpha.2) ranges from 85 to 15 wt. %; and
said at least one recurring unit having said pendant group represented by the formula (1) and/or (2) in (.alpha.1) is contained at a higher content than said at least one recurring unit in (.alpha.2).
Ethylenically Unsaturated Monomer Having a Pendant Group Represented by the Formula (1)
Examples of the ethylenically unsaturated monomer having the pendant group, which is represented by the following formula (1): ##STR17## wherein R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms, include ethylenically unsaturated monomers represented by the following formulas (3) to (6), respectively: ##STR18## wherein in the formula (4), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms; in the formula (5), R.sup.5 represents an alkylene group having 1-12 carbon atoms or an OH-containing alkylene group having 1-12 carbon atoms; in the formulas (3) to (6), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (6), n stands for an integer of 1-20.
Ethylenically Unsaturated Monomer Having a Pendant Group Represented by the Formula (2)
Examples of the ethylenically unsaturated monomer having the pendant group, which is represented by the following formula (2): ##STR19## wherein R.sup.3 represents an alkylene group having 1-30 carbon atoms, include ethylenically unsaturated monomers represented by the following formulas (7) to (9), respectively: ##STR20## wherein in the formulas (7) to (9), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (9), m stands for an integer of 1-16 and n stands for an integer of 0-14.
Examples of R.sup.6 in the formula (9) include the groups represented by the following formulas (10) and (11), respectively: ##STR21##
Illustrative of R.sup.7 in the formula (9) are the groups represented by the following formulas (12) to (14), respectively: ##STR22##
In the present invention, the content of said at least one monomer having the recurring unit(s) represented by the formula (1) and/or the formula (2) ranges, based on the whole monomers making up the (a2) or the (a1), from 0 to 40 wt. %, preferably from 0 to 30 wt. %, more preferably from 0 to 20 wt. % in (a2) and from 20 to 100 wt. %, preferably from 30 to 100 wt. %, more preferably 40-100 wt. % in (a1).
In addition, it is required that said at least one monomer having the recurring unit(s) containing the pendant group(s) represented by the formula (1) and/or (2) in (a1) be contained at a higher content than said at least one monomer (a2). The difference ranges preferably from 5 to 95 wt. %, more preferably from 20 to 90 wt. %, still more preferably from 40 to 80 wt. %.
Recurring Unit Having the Pendant Group Represented by the Formula (1)
Examples of the recurring unit having the pendant group represented by the following formula (1): ##STR23## wherein R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms, include recurring units represented by the following formulas (15) to (18), respectively: ##STR24## wherein in the formula (16), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms; in the formula (17), R.sup.5 represents an alkylene group having 1-12 carbon atoms or an OH-containing alkyl group having 1-12 carbon atoms; in the formulas (15) to (18), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (18), n stands for an integer of 1-20.
Recurring Unit Having the Pendant Group Represented by the Formula (2)
Examples of the recurring unit having the pendant group represented by the following formula (2): ##STR25## wherein R.sup.3 represents an alkylene group having 1-30 carbon atoms, include recurring units represented by the following formulas (19) to (21), respectively: ##STR26## wherein in the formulas (19) to (21), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (21), m stands for an integer of 1-16 and n stands for an integer of 0-14.
Examples of R.sup.6 in the formula (21) include the groups represented by the following formulas (10) and (11), respectively: ##STR27##
Illustrative of R.sup.7 in the formula (21) are the groups represented by the following formulas (12) to (14), respectively: ##STR28##
In the present invention, the content of the recurring unit(s) represented by the formula (1) and/or the formula (2) ranges, based on the whole recurring units, from 0 to 40 wt. %, preferably from 0 to 30 wt. %, more preferably from 0 to 20 wt. % in (a2) and from 20 to 100 wt. %, preferably from 30 to 100 wt. %, more preferably 40-100 wt. % in (.alpha.1).
In addition, it is required that said at least one recurring unit having the pendant group represented by the formula (1) and/or (2) in (.alpha.1) be contained at a higher content than said at least one recurring unit in (.alpha.2). The difference ranges preferably from 5 to 95 wt. %, more preferably from 20 to 90 wt. %, still more preferably from 40 to 80 wt. %.
Blocking
The term "blocking" as used herein means "compression bonding" as described, for example, under the entry of "blocking" in the right column on page 403 of "KOBUNSHI JITEN (Dictionary of Polymer Technology)", 1988 (compiled by: The Society of Polymer Science, Japan; published by: Asakura Shoten Co., Ltd.), and specifically means firm cohesion that polymer particles, which have been dispersed in a solvent, are brought into contact with each other and are bonded together at their surfaces of contact without permitting easy separation.
From the viewpoint of a principle, to show redispersibility means to allow polymer particles to individually disperse in water when added to water. If blocking, that is, cohesion of polymer particles takes place firmly, the polymer particles are brought into such a state that they can no longer readily separated from each other, leading to a reduction in redispersibility.
To show excellent redispersibility, it is therefore necessary to permit easy separation by suppressing blocking as much as possible.
The present invention has made it possible to allow polymer particles to exhibit superb redispersibility by associating a protective colloid or shells with polymer particles under particular conditions and suppressing blocking between the polymer particles.
Namely, the function of the protective colloid or shells in the present invention is essentially to act as a blocking preventive for polymer particles themselves. In the present invention, the protective colloid is therefore not absolutely required to exhibit a function as a stabilizer for emulsion polymerization. If the protective colloid does not function as a stabilizer for emulsion polymerization, it is only necessary to achieve a stable polymerization reaction by using a surfactant. In other words, the extent of exhibition of redispersibility in the present invention is closely correlated to the blocking-preventing function of the protective colloid or shells.
It is therefore very important to use the protective colloid (a1) and the (co)polymer (a2) of the ethylenically unsaturated monomer in proportions of 85-15 wt. % and 15-85 wt. %, respectively, based on the total weight of the (co)polymer (a2) and the protective colloid (a1) or shells (S).
Here, the proportion of the latter is preferably 15 wt. % or greater, more preferably 25 wt. % or greater, still more preferably 35 wt. % or greater, notably 45 wt. % or greater. Its upper limit is preferably 85 wt. % or less, more preferably 70 wt. % or less, especially 60 wt. % or less.
Further, the glass transition point of the protective colloid (a1) or shell (S) is preferably 20.degree. C. or higher, more preferably 30.degree. C. or higher, still more preferably 40.degree. C. or higher, notably 50.degree. C. or higher.
Preferred examples of the material of the protective colloid or shells include a copolymer having a carboxyl-containing recurring unit in addition to a recurring unit containing a pendant group represented by the formula (1) and/or a recurring unit containing a pendant group represented by the formula (2). In the case of the recurring unit of the formula (1), the proportion of the carboxyl-containing recurring unit ranges preferably from 0.5 to 30 wt. %, more preferably from 0.5 to 10 wt. %, still more preferably from 1 to 3 wt. %, all based on the copolymer. In the case of the recurring unit of the formula (2) on the other hand, the proportion of the carboxyl-containing recurring unit ranges preferably from 0.5 to 60 wt. %, more preferably from 0.5 to 40 wt. %, still more preferably from 0.5 to 20 wt. %, all based on the copolymer (a1).
The above-described copolymer having the carboxyl-containing recurring unit is characterized in that it has particularly good solubility in water and it easily flocculates in the flocculation step.
Anti-Blocking Property
As a common cause for blocking, the glass transition point (Tg) of polymer particles is so low that the polymer particles become soft and show tackiness in a high-temperature environment.
The term "anti-blocking property" as used herein embraces the property that neither compression bonding nor firm cohesion takes place even when polymer particles are brought into contact with each other.
B. Mechanism
Mechanism of Flocculation by the Addition of an Acid in a Flocculate-Forming Step
In a flocculate-forming step, a mineral acid and/or an organic acid is added to adjust the pH to 4 or lower, whereby (co)polymer particles (A) are caused to flocculate to form a flocculate (A') of the (co) polymer.
The scientific mechanism of the phenomenon that the (co)polymer particles (A) according to the present invention undergo flocculation in the presence of an acid has not been fully elucidated. However, the (co)polymer particles (A) are considered to flocculate into the flocculate (A') of the (cozpolymer by the addition of the mineral acid and/or the organic acid because of the existence of the protective colloid or shells (which have properties to undergo self-insolubilization and self-flocculation under acidic conditions) in the specific amount. In other words, it is presumed that the intervening protective colloid or shells are rendered hydrophobic at pH 4 or lower and act as a flocculant or the like, thereby flocculating the (co)polymer particles (A).
As flocculants, polymers which are called high-molecular flocculants and exhibit flocculating action are commonly known. These polymers are presumed to be adsorbed on suspended particles and then crosslinked there so that the suspended particles may be coarsened to undergo flocculation and settling. As an alternative, such polymers presumably lower the .zeta.-potential of surfaces of the suspended particles, whereby the suspended particles may flocculate together.
In the present invention, the protective colloid or shells are considered to induce flocculation of the (co)polymer particles (A) under acidic conditions in accordance with a similar mechanism.
Details of the above-described flocculation mechanism by a high-molecular flocculant is described in Eiji Ohmori: "Kobunshi Gyoshuzai (High-molecular Flocculants)", 1-90, 1975 (Kobunshi Kankokai, Inc.).
Mechanism of Flocculation by the Addition of a Metal Salt in a Flocculate-Forming Step
In a flocculate-forming step, (co)polymer particles (A) are caused to flocculate by the addition of a metal salt. The scientific mechanism of the phenomenon in which the (co)polymer particles according to the present invention flocculate with the metal salt has not been fully elucidated.
It is known to separate a solid polymer from a (co)polymer particle dispersion, which has been produced by emulsion (co)polymerization, by using a salting-out phenomenon, that is, by adding a metal salt and forming a flocculate.
From the standpoint of high-molecular physical chemistry, the following interactions are considered to take place between (co)polymer particles in an aqueous emulsion:
(1) van der Waals attraction (intermolecular attraction),
(2) electrostatic repulsion, and
(3) steric repulsion at particle surfaces.
The dispersing and flocculating properties of the (co)polymer particles are considered to be determined by the balance between these attraction and repulsions (repulsive forces).
In such a system, a metal salt primarily acts to lower electrostatic repulsion.
It is therefore considered that the addition of a metal salt to an aqueous emulsion, i.e., a system with a disperse phase [(co)polymer particles] evenly dispersed in a continuous phase (water) reduces the repulsion between the (co)polymer particles and hence converts the (co)polymer particles from a dispersed form into a flocculated form.
Details of the above-described consideration of the flocculation mechanism of (co)polymer particles from the standpoint of high-molecular physical chemistry are descried on pages 187-200 of Soichi Muroi: "tKohbunshi Ratekkusu no Kagaku (Chemistry of High-Molecular Latex)", 1980 (Kobunshi Kankokai, Inc).
At least a part of the mechanism of flocculation by the addition of a metal salt in the flocculate-forming step is presumed to take place in the above-described mechanism.
Mechanism of the Exhibition of a Function to be Substantially Redispersible in Water of pH 5 or Higher
When an aqueous emulsion prepared in an aqueous emulsion preparation step is dried by spray drying, marked cohesion of (co)polymer particles (A) generally takes place because they are dried fast at high temperatures. As a consequence, the redispersibility is substantially lowered. Moreover, a great deal of deposit occurs on a wall of a drying tower so that the operability and productivity are lowered.
However, the formation of a flocculate (A') of a (co)polymer by the flocculate-forming step of the production process according to the present invention makes it possible to obtain the copolymer having a function to be substantially redispersible in water either directly or after drying the flocculate or further grinding the thus-dried flocculate.
Further, the flocculate (A') of the (co)polymer may be subjected to thorough washing either during and/or after its solid/liquid separation upon its recovery. Any mixed free protective colloid, free acid and other free water-soluble substances are hence removed, thereby making it possible to eliminate substances which would otherwise give undesired effects to the properties of the flocculate (A') of the (co)polymer.
General examples, as primary particles, of the (co)polymer particles (A) obtained by the production process according to the present invention include composite particles which are each formed of the (co)polymer of the ethylenically unsaturated monomer (a2) and the protective colloid (al) deposited or otherwise applied on the (co)polymer.
The general examples, as primary particles, of the (co)polymer particles (A) obtained by the production process according to the present invention also include composite particles which are each formed of the (co)polymer particle of the ethylenically unsaturated monomer (a2) and the protective colloid (a1) existing in a large amount on an outer wall of the (co)polymer particle.
The (co)polymer particles (A) which are obtained in the aqueous emulsion preparation step can be converted to the flocculate (A') of the (co)polymer, which has a function to be substantially redispersible in water, by flocculating the (co)polymer particles in the flocculate-forming step of the production process according to the present invention.
It is presumed that in the thus-formed flocculate (A') of the (cozpolymer, the interaction of the (co)polymer particles of the ethylenically unsaturated monomer (a2) contained in the (co)polymer particles (A) is reduced by the buffer action of the protective colloid (a1) contained in the (co)polymer particles (A) to control the strength of cohesion of the particles themselves, thereby allowing the flocculate (A') of the (co)polymer to show a function to be substantially redispersible in water.
Problems of Spray Drying
Spray drying is a method for effecting drying by spraying an aqueous dispersion of (co)polymer particles through nozzles into a high-temperature gas.
According to spray drying, capillary water between (co)polymer particles abruptly evaporates upon conducting drying of a dispersion of the (co)polymer particles by spraying it through nozzles into a high-temperature gas. Since a pressure resulting from a capillary pressure is applied between the (co)polymer particles and heat of the system is applied to the particles, strong cohesion takes place between the particles themselves, resulting in the problem that the particles become susceptible to irreversible cohesion. This capillary pressure theory upon cohesion of the (co)polymer particles themselves is described in detail on pages 242-248 of Soichi Muroi: I"Kohbunshi Ratekkusu no Kagaku (Chemistry of High-Molecular Latex)", 1980 (Kobunshi Kankokai, Inc).
It should be worthy to note that the present invention can avoid the application of unnecessary capillary pressure and high temperature to particles owing to the formation of a flocculate without heating the particles although the application of such capillary pressure and intense heat is inevitable in the case of spray drying.
In the present invention, it is possible to bring the particles into a dispersed form without cohesion between the particles or, even if such cohesion takes place, by reversibly, easily and substantially destructing the state of cohesion.
In the present invention, the reversible state of cohesion between particles (namely, the state which can be substantially and reversibly brought back to a dispersed state even after a cohered state is once formed) can be controlled by suitably choosing conditions for flocculating particles, for example, the temperature, the amount of an acid to be used for flocculation and the like upon conducting flocculation. It is therefore possible to practically avoid the irreversible state of cohesion between particles (namely, the state which cannot be substantially and reversibly brought back to a dispersed state once a cohered state is formed) which is unavoidable in the case of spray drying.
Polymerization of Protective Colloid or Shells
In the present invention, the protective colloid or shells, when taken singly, are water-soluble or hydrophilic, and have property to insolubilize and flocculate under acidic conditions or in the presence of a metal salt and also anti-blocking property.
Namely, the degree of development of redispersibility in the present invention is closely correlated to the anti-blocking function of the protective colloid or shells.
It is therefore very important, in the radical (co)polymerization of the protective colloid (a1) or shells (S), to use at least one monomer selected from the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (1) and the group consisting of ethylenically unsaturated monomers having pendant groups represented by the following formula (2): ##STR29## wherein in the formula (1), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms and in the formula (2), R.sup.3 represents an alkylene group having 1-30 carbon atoms.
It is also very important to use the ethylenically unsaturated monomer (a2) and the protective colloid (a1) or shells (S) in proportions of from 85 to 15 wt. % and from 15 to 85 wt. %, respectively, based on the total weight of the former and the latter. Here, the proportion of the latter is preferably 15 wt. % or greater, more preferably 25 wt. % or greater, more preferably 35 wt. % or greater, notably 45 wt. % or greater.
Further, the calculated glass transition point of the protective colloid (a1) or shells (S) is preferably 20.degree. C. or higher, more preferably 30.degree. C. or higher, still more preferably 40.degree. C. or higher, notably 50.degree. C. or higher. No particular limitation is imposed on its upper limit, but one having a glass transition point of 300.degree. C. or so can be preferably used.
Preferred examples of the material of the protective colloid or shells include a copolymer having a carboxyl-containing recurring unit in addition to the essential element or elements, that is, the recurring unit containing the pendant group represented by the formula (1) and/or the recurring unit containing a pendant group represented by the formula (2). In the case of the recurring unit of the formula (1), the proportion of the carboxyl-containing recurring unit ranges preferably from 0.5 to 30 wt. %, more preferably from 0.5 to 10 wt. %, still more preferably from 1 to 3 wt. %, all based on the copolymer. In the case of the recurring unit of the formula (2) on the other hand, the proportion of the carboxyl-containing recurring unit ranges preferably from 0.5 to 60 wt. %, more preferably from 0.5 to 40 wt. %, still more preferably from 0.5 to 20 wt. %, all based on the copolymer (a1).
Ethylenically Unsaturated Monomer Having a Pendant Group Represented by the Formula (1)
Examples of the ethylenically unsaturated monomer having the pendant group, which is represented by the following formula (1), include ethylenically unsaturated monomers represented by the following formulas (3) to (6), respectively: ##STR30## wherein in the formula (4), R.sup.1 and R.sup.2 are either the same or different and individually represent a hydrogen atom, an alkyl group having 1-12 carbon atoms, or an OH-containing alkyl group having 1-12 carbon atoms; in the formula (5), R.sup.5 represents an alkylene group having 1-12 carbon atoms or an OH-containing alkylene group having 1-12 carbon atoms; in the formulas (3) to (6), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (6), n stands for an integer of 1-20.
Upon frequently referring herein to the ethylenically unsaturated monomer having the pendant group represented by the formula (1), the term "ethylenically unsaturated, amido-containing monomer" may be used for the sake of convenience.
Specific examples of the ethylenically unsaturated, amido-containing monomer include acrylamide, methacrylamide, N-methylol methacrylamide, N-methylol acrylamide, N-acryloylpyridine, N,N-dimethylacrylamide, N-isopropylacrylamide, N-hexylacrylamide, N-octylacrylamide, N-dodecylacrylamide, N,N-diethylacrylamide, N-acryloylpyrrolidine, diacetone acrylamide, and maleic amide. Of these, particularly preferred are methacrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N-hexylacrylamide, N-octylacrylamide, N,N-diethylacrylamide, and N-acryloylpyrrolidine, They can be used either singly or in combination. Methacrylamide is especially preferred.
Concept of the Word "Amido Group"
The concept of the word "amido group" as used herein completely encompasses the concept which this word generally has in high-molecular chemistry, but they are not completely equivalent to each other. For example, "Kagagu Daijiten (ENCYCLOPAEDIA CHIMICA)", Volume 1 (a,i,u,e), 1960 (Kyoritsu Shuppan Co., Ltd.) contains an annotation of the term "amido or amide" in the left column on page 244, where the term "amido or amide" is defined as "1]". The name of a group in the form of RCONH-- formed as a result of bonding of an amino group, --NH.sub.2, with an acid group (acyl group). For example, CH.sub.3 CONH-- is called "acetamido". [2](1) (Compound obtained) by substituting one or more acid groups (acyl groups) for the like number of hydrogen atoms of ammonia. RCONH.sub.2. Same as the "acid amides.". The concept of the term "amido group" as used herein completely embraces the concept recognized in general chemistry as described in the "Kagagu Daijiten (ENCYCLOPAEDIA CHIMICA)" and also fully encompasses the concept based on the pendant group represented by the formula 1.
Ethylenically Unsaturated Monomer Having a Pendant Group Represented by the Formula (2)
Examples of the ethylenically unsaturated monomer having the pendant group, which is represented by the formula (2), include ethylenically unsaturated monomers represented by the following formulas (7) to (9), respectively: ##STR31## wherein in the formulas (7) to (9), R.sup.4 represents a hydrogen atom or an alkyl group having 1-12 carbon atoms; and in the formula (9), m stands for an integer of 1-16 and n stands for an integer of 0-14.
Examples of R.sup.6 in the formula (9) include the groups represented by the following formulas (10) and (11), respectively: ##STR32##
Illustrative of R.sup.7 in the formula (9) are the groups represented by the following formulas (12) to (14), respectively: ##STR33##
Upon frequently referring herein to the ethylenically unsaturated monomer having the pendant group represented by the formula (2), the expression "OH-containing ethylenically unsaturated monomer" may be used for the sake of convenience. A (co)polymer making use of this "OH-containing ethylenically unsaturated monomer" can be preferably used for cement as it provides good stability.
Specific examples of the OH-containing ethylenically unsaturated monomer preferably include (meth)-acrylates such as hydroxymethyl (meth)acrylates, 2-hydroxyethyl (meth)acrylates, hydroxypropyl (meth)-acrylates, hydroxybutyl (meth)acrylates, hydroxypentyl (meth)acrylates, polyethylene glycol mono(meth)-acrylates, polypropylene glycol mono(meth)acrylates, polyethylene glycol polypropylene glycol mono(meth)-acrylates, polyethylene glycol polytetramethylene glycol mono(meth)acrylates, and polypropylene glycol polytetramethylene glycol (meth)acrylates. They can be used either singly or in combination.
Particularly preferred is 2-hydroxyethyl methacrylate.
Carboxyl-Containing Ethylenically Unsaturated Monomer
Particularly preferred specific examples of the carboxyl-containing ethylenically unsaturated monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, acrylic anhydride, methacrylic anhydride, maleic anhydride, itaconic anhydride and fumaric anhydride.
Other Ethylenically Unsaturated Monomer
As particularly preferred specific examples of the ethylenically unsaturated monomer which makes up (a1) and is other than the ethylenically unsaturated monomer having the pendant group represented by the formula (1), the ethylenically unsaturated monomer having the pendant group represented by the formula (2) and the carboxyl-containing ethylenically unsaturated monomers, ethylenically unsaturated monomers copolymerizable with unsaturated monomers, such as those to be described below under (1) to (3), can be mentioned.
(1) Acrylates of alkyl groups having 1-12 carbon atoms, such as methyl, ethyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, 2-ethylhexyl, octyl, decyl, dodecyl, octadecyl, cyclohexyl, phenyl, and benzyl acrylates.
(2) Methacrylates of alkyl groups having 1-12 carbon atoms, such as methyl, ethyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, 2-ethyl-hexyl, octyl, decyl, dodecyl, octadecyl, cyclohexyl, phenyl, and benzyl methacrylates.
(3) Others such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate, styrene, acrylonitrile, methacrylonitrile, sodium styrenesulfonate, and acrylamido-2-methylpropanesulfonic acid and the sodium salt thereof.
Initiator
No particular limitation is imposed on the initiators which are used in the present invention, namely, in the protective colloid formation step and the shell polymerization step. Usable examples include hydrogen peroxide; persulfates such as ammonium persulfate and potassium persulfate; sodium azobiscyanovalerate; and redox initiators composed of such compounds, metal ions such as iron ions and reducing agents such as sodium sulfoxylate, formaldehyde, sodium pyrosulfite, sodium hydrogensulfite and L-ascorbic acid.
These polymerization initiators are generally used in a proportion of from 0.01 to 25 parts by weight per 100 parts by weight of all the monomers which are charged upon polymerization of the protective colloid (a1) or shells (S).
Molecular Weight Regulator
In the present invention, a mercaptan such as t-dodecyl mercaptan or n-dodecyl mercaptan or an allyl compound such as allylsulfonic acid, methallylsulfonic acid or the sodium salt thereof can be used as a molecular weight regulator, as needed, in the protective colloid formation step or the shell polymerization step.
Properties of Protective Colloid or Shells
In the present invention, no particular limitation is imposed on the protective colloid (a) or shells (S) insofar as, when taken individually, it is a substantially water-soluble or hydrophilic (co)polymer and has property to insolubilize and flocculate under acidic conditions or in the presence of a metal salt. The weight average molecular weight of the protective colloid (a1) generally ranges from 1,000 to 500,000, preferably from 1,000 to 350,000, more preferably from 1,000 to 200,000.
To provide the flocculate (A') of the (co)polymer with practically complete dispersibility, the calculated value of the glass transition point of the protective colloid (a1) or shells (S) is preferably 20.degree. C. or higher, more preferably 30.degree. C. or higher, still more preferably 40.degree. C. or higher, notably 50.degree. C. or higher.
Ethylenically Unsaturated Monomer for Forming (a2)
No particular limitation is imposed on the ethylenically unsaturated monomer employed in the present invention for forming (a2), insofar as it undergoes substantial polymerization and forms desired (co)polymer particles. Specific examples of the ethylenically unsaturated monomer include those employed for the production of aqueous emulsions which are used for applications such as construction materials, papermaking chemicals, paints, adhesives and fiber finishes.
Specific examples of the ethylenically unsaturated monomer include:
acrylate esters, for example, methyl, ethyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, 2-ethylhexyl, octyl, decyl, dodecyl, octadecyl, cyclohexyl, phenyl, benzyl, 2-hydroxyethyl, and hydroxypropyl acrylates;
methacrylate esters, for example, methyl, ethyl, isopropyl, n-butyl, isobutyl, n-amyl, isoamyl, n-hexyl, 2-ethylhexyl, octyl, decyl, dodecyl, octadecyl, cyclohexyl, phenyl, benzyl, 2-hydroxyethyl, and hydroxypropyl methacrylates;
the acrylates of other alkyl groups having 3-12 carbon atoms;
the methacrylate of other alkyl groups having 3-12 carbon atoms;
2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, acrylonitrile, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether;
unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, acrylic anhydride, methacrylic anhydride, maleic anhydride, itaconic anhydride, and fumaric anhydride;
amino-containing monomers such as N-methylaminoethyl acrylate, N-methylaminoethyl methacrylate, dimethylaminoethyl acrylate, and dimethylaminoethyl methacrylate;
aromatic vinyl compounds such as styrene, 2-methylstyrene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, and divinylbenzene;
vinyl esters such as vinyl acetate, vinyl propionate, and fatty acid vinyl esters (e.g., "VeoVa", trade mark; product of Shell Japan Ltd.);
halogenated vinyl compounds such as vinyl chloride;
halogenated vinylidene compounds such as vinylidene chloride, and vinylidene fluoride;
olefins such as ethylene, propylene, isoprene, butadiene and chloroprene;
others such as vinylpyrrolidone, acrylonitrile, methacrylonitrile, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, trimethylol propane trimethacrylate, trimethylol propane triacrylate, tetramethylol methane triacrylate, tetramethylol methane tetraacrylate, allyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, isopropenyl-.alpha.,.alpha.-dimethylbenzyl isocyanate, and allyl mercaptan; and
amides such as acrylamide, methacylamide, N-methylolmethacrylamide, N-methylolacrylamide, diacetoneacrylamide, and maleamide.
They can be used either singly or in combination.
Among these, preferred are aromatic vinyl compounds, dienes, olefins, (meth)acrylates and vinyl esters. Preferred specific examples include styrene, butyl acrylate, 2-ethylhexyl acrylate, butadiene, methyl methacrylate, vinyl acetate, "VeoVa", and ethylene. For use in cement, alkali-resistant monomers are preferred.
Polymerization Process
No particular limitation is imposed on the polymerization process for the aqueous emulsion preparation step or the core particle preparation step in the present invention, insofar as an aqueous emulsion formed of a disperse phase of the (co)polymer particles (A) and a continuous phase of water can be prepared. In general, however, emulsion polymerization is preferably adopted. In emulsion polymerization, a surfactant, a pH regulator and the like can be used as needed insofar as the use of such additives conforms with the objects of the present invention.
Specific examples of the polymerization process usable for the aqueous emulsion preparation step or the core particle preparation step in the present invention include:
(1) a process in which polymerization is conducted by adding a polymerization initiator in the presence of the ethylenically unsaturated monomer (a2);
(2) a process in which a polymerization initiator is added and polymerization is then conducted while adding the ethylenically unsaturated monomer (a2) dropwise (suited when intense heat is given off by the polymerization);
(3) a process in which a polymerization initiator is dissolved in the ethylenically unsaturated monomer (a2) and polymerization is conducted while adding the thus-prepared solution dropwise; and
(4) a process in which a polymerization initiator is dissolved in an appropriate solvent and polymerization is conducted while adding the thus-prepared solution and the ethylenically unsaturated monomer (a2) dropwise at the same time but separately.
Specific examples of the polymerization process usable for the protective colloid formation step in the present invention include:
(1) a process in which monomer(s) as component(s) for the protective colloid are mixed and then heated to a desired polymerization temperature, followed by the addition of a polymerization initiator to conduct polymerization;
(2) a process in which a polymerization initiator is added and polymerization is then conducted while adding dropwise monomer(s) as component(s) for the protective colloid (suited when intense heat is given off by the polymerization);
(3) a process in which a polymerization initiator is dissolved in monomer(s) as components (s) for the protective colloid and polymerization is conducted while adding the thus-prepared solution dropwise; and
(4) a process in which a polymerization initiator is dissolved in an appropriate solvent and polymerization is conducted while adding the thus-prepared solution and monomer(s) as component(s) for the protective colloid dropwise at the same time but separately.
Since protective colloid polymerization can be adopted for the aqueous emulsion preparation step in the present invention, the polymerization in the presence of a protective colloid can bring about the advantage that the stability of the polymerization is improved and the amount of a surfactant to be used can be reduced.
As an hydrophilic, ethylenically unsaturated monomer having a pendant group represented by the formula (1) or the formula (2) is used for the shell polymerization step in the present invention, an advantage can be brought about that the stability of the polymerization is improved and the amount of a surfactant to be used can be reduced.
Because the surfactant can be used in a smaller amount, a further advantage can be brought about that, when a redispersion of the redispersible polymer is formed into a film, the film can be provided with improved waterproofness.
According to the production process of the present invention, the polymerization of the ethylenically unsaturated monomer (a1) is conducted in the presence of a protective colloid (a1) which will be described subsequently herein. This polymerization can be conducted following ordinary emulsion polymerization, that is, the ethylenically unsaturated monomer (a1) is polymerized in the absence of the protective colloid (a1).
Surfactant
No particular limitation is imposed on the surfactant usable for the emulsion polymerization process adopted in the present invention, insofar as a disperse phase can be formed practically in a long-lasting uniform and stable form in a water-based continuous phase. As the surfactant, known surfactants which are employed in ordinary emulsion polymerization can be suitably used either singly or in combination.
Specific examples of nonionic surfactants, anionic surfactants and cationic surfactants will be listed below. They can be suitably used either singly or in combination.
(1) Nonionic Surfactants
Specific examples of a nonionic surfactant usable in step 1 (aqueous emulsion preparation step) of the production process according to the present invention include polyoxyethylene lauryl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, and oxyethylene-oxypropylene block copolymer. They can be used either singly or in combination.
(2) Anionic Surfactants
Specific examples of an anionic surfactant usable in step 1 (aqueous emulsion preparation step) of the production process according to the present invention include sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium alkyl diphenyl ether disulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, potassium stearate, potassium oleate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium stearate, and sodium oleate. They can be used either singly or in combination.
(3) Cationic Surfactants
Specific examples of a cationic surfactant usable in step 1 (aqueous emulsion preparation step) of the production process according to the present invention include lauryltrimethylammonium chloride and stearyltrimethylammonium chloride. They can be used either singly or in combination.
Amount of Surfactant to be Used
No particular limitation is imposed on the amount of the surfactant to be used, insofar as it is used in an amount sufficient to practically form micelles in a reaction system or in an amount sufficient to form a disperse phase practically in a long-lasting uniform and stable form in a water-base continuous phase.
As the kind and concentration of the surfactant, it is generally necessary to adequately choose conditions sufficient to substantially achieve desired particle properties (layer structure, shape, particle size, particle size distribution, etc.) while taking into consideration the CMC (critical micelle concentration) value inherent to the surfactant and HLB (hydrophilic-lipophilic balance) value.
In general, the surfactant can be used in an amount of from 0.1 to 10 wt. % based on the total weight of all monomers supplied to the reaction system.
Polymerization Initiator
No particular limitation is imposed on the polymerization initiator usable in the emulsion polymerization process adopted in the present invention, insofar as it can substantially show a function to initiate polymerization.
Specific examples of the polymerization initiator include hydrogen peroxide; persulfates such as ammonium persulfate and potassium persulfate; organic peroxides such as cumene hydroperoxide and tert-butyl hydroperoxide; azo compounds such as azobisisobutyronitrile; and redox initiators composed of such compounds, metal ions such as iron ions and reducing agents such as sodium sulfoxylate, formaldehyde, sodium pyrosulfite, sodium hydrogensulfite and L-ascorbic acid.
These polymerization initiators are used in an amount of 0.01-15 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer (a2).
Molecular Weight Regulator
In the present invention, the preferred weight average molecular weight of the (co)polymer particles (A) generally ranges from 50,000 to 90,000,000.
Particle Size of (Co)Polymer Particles (A)
Concerning the particle size of the (co)polymer particles (A), the average particle size as measured in a wet state by the laser light scattering method can range preferably from 50 to 5,000 nm, more preferably from 70 to 3,000 nm, still more preferably from 100 to 1,000 nm.
In general, as the particle size is progressively reduced beyond 50 nm, the viscosity of the redispersion of the flocculate (A') of the (co)polymer is observed to have a tendency to rapidly increase and the workability upon use is observed to have a tendency to become poorer, and because the specific surface area of the particles progressively increases, the stability of the redispersion itself of the flocculate (A') of the (co)polymer is observed to have a tendency to drop correspondingly.
On the other hand, as the particle size is progressively increased beyond 5,000 nm, it is generally observed that the film-forming ability of the redispersion drops and a composition obtained by adding the particles according to the present invention tends to have lower waterproofness and strength.
Properties of Aqueous Emulsion Prepared in the Core Particle Polymerization Step
As the aqueous emulsion prepared in the core particle polymerization step of the present invention, a redispersible polymer capable of forming a redispersion which forms a film when dried at room temperature is useful. Upon production of such a redispersible polymer, it is effective to use an aqueous emulsion which forms a film when dried at room temperature.
Especially, to make it possible to form a film by room-temperature drying, Tg as determined in accordance with the Fox's equation ranges preferably from about -40.degree. C. to about +30.degree. C, more preferably from about -30.degree. C. to about +20.degree. C. It is important in the present invention that the polymer of the cores has Tg lower than that of the shells. Their temperature difference can be preferably 10.degree. C. or greater, more preferably 40.degree. C. or greater.
As a polymerization process to be adopted for the core particle polymerization step in the present invention, emulsion polymerization is most preferred because it can easily obtain core particles of a smaller particle size, facilitates the control of the particle size, and is excellent in stability.
Mineral Acid and/or Organic Acid Employed in the Flocculate Forming Step
No particular limitation is imposed on the mineral acid and/or organic acid employed in the flocculate forming step, insofar as they have a function to insolubilize the (co)polymer particles (A) as the flocculate (A') of the (co)polymer.
Specific examples of the mineral acid and organic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and acetic acid. They can be used either singly or in combination. Sulfuric acid is particularly preferred, as it can be added in a smaller amount and does not contain chlorine.
Manner of Addition of Mineral Acid and/or Organic Acid in the Flocculate Forming Step
It is also effective to add an alcohol or electrolyte upon formation of a flocculate to facilitate the occurrence of flocculation by making combined use of coagulation or salting-out. Preferred as the electrolyte are those containing aluminum ions and capable of showing their effects in a small amount. For example, aluminum sulfate can be mentioned.
No particular limitation is imposed on the temperature of the emulsion system upon addition of the mineral acid and/or organic acid, insofar as the temperature is in such a range as allowing the aqueous emulsion or the mixture of the aqueous emulsion and the protective colloid to retain a liquid phase. The temperature of the emulsion system upon addition of an acid is generally in a range of from 0 to 100.degree. C. As flocculation is caused to occur at a higher temperature, the resulting flocculate lumps become more solid and greater so that their solid-liquid separation becomes easier. In some instances, however, cohesion of particles may become stronger upon flocculation so that the redispersibility may be reduced. In general, the temperature ranges preferably from 10.degree. C. to 80.degree. C., more preferably from 20.degree. C. to 60.degree. C.
It is also possible to induce flocculation by raising the temperature of the system subsequent to the addition of an acid.
Amount of Mineral Acid and/or Organic Acid to be Added in the Flocculate Forming Step
In general, the mineral acid and/or organic acid can be added preferably in an amount sufficient to adjust the pH of the aqueous emulsion or the mixture of the aqueous emulsion and the protective colloid to 4 or lower, more preferably in an amount sufficient to adjust its pH to 3 or lower.
Generally, addition of the acid in an unduly small amount may lead to incomplete flocculation and difficult solid-liquid separation, whereas addition of the acid in an excessively large amount may lead to a failure in allowing the (co)polymer particles (A) to exhibit their inherent properties or to difficulty in eliminating the acid by washing same during and/or after solid-liquid separation.
Manner of Addition of Mineral Acid and/or Organic Acid in the Flocculate Forming Step
No particular limitation is imposed on the manner of addition of the mineral acid and/or organic acid.
It is generally preferred to use the acid in the form of an aqueous solution for mixing the acid more uniformly and also from the standpoint of safety, although the acid is not necessarily limited to such a solution.
In general, it is preferred to add the acid in the form of a 50% or lower aqueous solution.
Metal Salt for Use in the Flocculate Forming Step
No particular limitation is imposed on the metal salt to be used in the flocculate forming step, insofar as it has a function to insolubilize the (co)polymer particles (A) as the flocculate (A') of the (co)polymer.
Specific examples of the metal salt include aluminum salts such as aluminum sulfate, aluminum chloride, ammonium alum, potassium alum, aluminum polychloride and aluminum polysulfate; iron salts such as ferrous sulfate, ferric sulfate, ferric chloride, ferric polychloride and ferric polysulfate; zinc salts such as zinc chloride and zinc sulfate; magnesium salts such as magnesium oxide, magnesium carbonate and magnesium sulfate; and others, including aluminum hydroxide, iron hydroxide, calcium chloride, sodium chloride, calcium thiosulfate, calcium nitrite, calcium formate, calcium sulfate and potassium nitrate. They can be used either singly or in combination. As the valence of a metal ion becomes higher, the flocculating power becomes stronger so that flocculation can be induced using the metal salt in a smaller amount. Use of an aluminum salt or iron salt is hence preferred in general. Such an aluminum salt or iron salt is also preferred from the standpoint of the safety of effluent or the like.
pH Upon Addition of Metal Salt in the Flocculate Forming Step
Upon addition of the metal salt, it is generally preferred to adjust the pH to a level of from 6 to 2, more preferably from 5 to 3.
This is because, as the acidity increases, the metal can be used in a smaller amount, a flocculate permitting easier solid-liquid separation is formed, and the yield is improved.
Here, use of a mineral acid and/or organic acid as a pH regulator is feasible. Specific examples of the pH regulator include hydrochloric acid, sulfuric acid, phosphoric acid and acetic acid. Sulfuric acid is preferred as a pH regulator, because it can be added in a smaller amount and does not contain chlorine.
No particular limitation is imposed on the temperature of the emulsion system upon addition of the metal salt, insofar as the temperature is in such a range as allowing the aqueous emulsion, which has been obtained in step 2 (aqueous emulsion preparation step), to retain a liquid phase. The temperature of the emulsion system at the time of the addition of the metal salt generally ranges from 0 to 100.degree. C. In general, however, the temperature ranges preferably from 10.degree. C. to 80.degree. C., more preferably from 20.degree. C. to 60.degree. C. because, as the flocculation is caused to occur at a higher temperature, the resulting flocculate lumps become more solid and greater and permits easier solid-liquid separation.
Amount of the Metal to be Added in the Flocculate Forming Step
In general, the amount of the metal to be added is preferably from 0.01 to 70 wt. %, more preferably from 1 to 50 wt. %, still more preferably from 5 to 30 wt. %, all, based on the solid content of the (co)polymer particles (A).
Generally, addition of the metal salt in an unduly small amount may lead to incomplete flocculation and difficult solid-liquid separation, whereas addition of the metal salt in an excessively large amount may lead to a failure in allowing the (co)polymer particles (A) to exhibit their inherent properties or to difficulty in eliminating the metal salt by washing same during and/or after solid-liquid separation.
Manner of Addition of the Metal Salt in the Flocculate Forming Step
No particular limitation is imposed on the manner of addition of the metal salt.
It is generally preferred to add the metal salt in the form of an aqueous solution from the standpoint of safety, although the metal salt is not necessarily limited to such a solution.
Examples of the manner of addition of the metal salt include:
(1) addition of the metal salt in a solid form to the aqueous emulsion; and
(2) addition of the metal salt to the aqueous emulsion after converting the metal salt into an solution by dissolving it in a solvent capable of dissolving same at a predetermined concentration or higher.
Separation Method, Drying Method and Grinding Method of the Flocculate (A') of the (Co)Polymer
No particular limitation is imposed on the solid-liquid separation method in the process of the present invention, insofar as it is generally employed. In particular, a commonly employed method such as filtration, centrifugation or decantation can be used. Further, the separated flocculate can also be used after drying same.
No particular limitation is imposed on the drying method. For example, the flocculate can be dried by hot-air drying, vacuum drying or the like. The flocculate may undergo further flocculation by drying.
A redispersible polymer--which is available by completely drying a flocculate, which has been subjected to solid-liquid separation, at a temperature of from room temperature to 100.degree. C.--is generally crushable because it is hard and does not have tackiness.
No particular limitation is imposed on the crushing method of the dried redispersible polymer, and a conventional equipment, for example, a hammer mill, a jet mill, a pin mill or the like can be used. This crushing is not required to crush the polymer into primary particles. It is only necessary to crush the polymer to powder in a form convenient for further processing.
To increase the redispersing speed, it is desired to crush the polymer to an average particle size of 1 mm or smaller, with 500 .mu.m or smaller being more preferred and with 300 .mu.m or smaller being still more preferred.
Utility and Application--Hydraulic Cement Composition
The redispersible polymer according to the present invention can be preferably used as a modifier for hydraulic cement. A hydraulic cement composition can be modified by mixing the redispersible polymer in an amount of from 0.5 to 60 wt. %, preferably from 1 to 40 wt. %, still more preferably from 2 to 20 wt. %, all, based on the hydraulic cement.
Utility and Application--Placing Method of Hydraulic Cement
An excellent hardened cement structure can be obtained by mixing 0.5-60 wt. %, preferably 1-40 wt. %, more preferably 2-20 wt. %, based on hydraulic cement, of the redispersible polymer according to the present invention and water with the cement and then placing the mixed concrete. The use of the redispersible polymer according to the present invention as a cement additive can bring about the following marked advantageous effects:
1. improvement in flexural strength;
2. improvement in tensile strength;
3. improvement in bonding strength (which leads to an improvement in the bonding strength to hardened mortar or concrete, plywood, metal, tiles or the like);
4. retention of bonding strength after immersed in water;
5. retention of bonding strength over a long period of time;
6. reduction in the amount of water to be used and hence, an improvement in strength owing to the use of water in the reduced amount, because the redispersible polymer according to the present invention can improve the flowability upon mixing hydraulic cement and has effects as a water reducing agent; and
7. prevention of introduction of air into a mixed cement because the mixing can be completed in a short time owing to the excellent redispersibility.
8. improvement in anti-permeability.
9. improvement in wear resistance.

EXAMPLES
To more specifically describe the present invention, the present invention will be described further on the basis of the following examples and comparative examples.
It should however be borne in mind that in the present specification, the examples, production examples and embodiments are to assist the understanding of the details of the present invention and are not intended to limit the present invention.
All designations of "%", which will follow, refer to "wt. %" unless specified otherwise.
Abbreviations of various raw materials, which will appear in tables to be described in the following examples and comparative examples, are shown below:
MAm: methacrylamide,
AAm: acrylamide,
HEA: 2-hydroxyethyl acrylate,
HEMA: 2-hydroxyethyl methacrylate,
MAc: methacrylic acid,
ST: styrene,
BA: n-butyl acrylate,
n-DM: n-dodecylmercaptan,
MMA: methyl methacrylate,
t-DM: t-dodecylmercaptan,
BD: butadiene,
AN: acrylonitrile,
AA: acrylic acid,
Al.sub.2 (SO.sub.4).sub.3 : aluminum sulfate,
CaCl.sub.2 : calcium chloride, and
FeSO.sub.4 : ferric sulfate.
1. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by protective colloidal polymerization, with an acid (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 1-1
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785.0 g of purified water and 150.0 g of methacrylamide were charged. Under stirring in a nitrogen gas atmosphere, the contents were heated to 75.degree. C. and were maintained at the same temperature. After the methacrylamide was completely dissolved, 45.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 75.degree. C. for 7 hours.
Aqueous ammonia and purified water were added to the resultant mixture, whereby a protective colloid (B-1) of 15% resin content and pH 7 was obtained. When that protective colloid (B-1) was acidified to pH 3 with sulfuric acid, flocculation of a polymer took place.
Protective Colloid Polymerization
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 666.7 g of the protective colloid (B-1) were charged, followed by the addition of 0.5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above protective colloid at 80.degree. C. over 3 hours, followed by stirring at 80.degree. C. for 3 hours.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gStyrene 40.0 gn-Butyl acrylate 50.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-1) of 10% resin content and pH 9 was prepared.
(2) Step 2 (Flocculate Forming Step)
When a 5% aqueous solution of sulfuric acid was added at room temperature to 1,000 g of (C-1) until the pH dropped to 2.5, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less [note: The residual water content was measured by the measuring method of weight loss on heating prescribed under K5407.5 of JIS (Japanese Industrial Standards). All residual water contents described herein are values measured by this method.]. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Example 1-2
Following the procedures of Example 1-1, a protective colloid (B-2) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-2) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.]Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-2) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-3
Following the procedures of Example 1-1, a protective colloid (B-3) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-3) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.]Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-3) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-4
Following the procedures of Example 1-1, a protective colloid (B-4) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-4) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.] Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-4) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-5
Following the procedures of Example 1-1, a protective colloid (B-5) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-5) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.] Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-5) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-6
Following the procedures of Example 1-1, a protective colloid (B-6) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-6) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.] Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-6) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-7
Following the procedures of Example 1-1, a protective colloid (B-7) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-7) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.] Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-7) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-8
Following the procedures of Example 1-1, a protective colloid (B-8) was prepared in accordance with a composition shown in Table 1-1. [When the pH of this protective colloid (B-8) was lowered to pH 3 with sulfuric acid, flocculation of a polymer took place.] Protective colloid polymerization was then conducted to prepare an aqueous emulsion (C-8) of 10% resin content and pH 9. Redispersible polymer powder was obtained by similar procedures.
Example 1-9
Following the procedures of Example 1-1, a protective colloid (B-1) was prepared in accordance with the composition shown in Table 1-1. Protective colloid polymerization was then conducted under the below-described conditions, whereby an aqueous emulsion (C-9) of 10% resin content and pH 9 was prepared. Redispersible polymer powder was obtained by similar procedures.
Protective Colloid Polymerization
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 400 g of the protective colloind (B-1) and 210 g of purified water were charged, followed by the addition of 0.7 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsified monomer mixture of the below-described composition was prepared. The emulsified monomer mixture was added dropwise to the above aquoues solution at 80.degree. C. over 3 hours, followed by aging for 3 hours.
______________________________________Purified water 56.0 gSodium dodecylbenzenesulfonate 0.14 gStyrene 56.0 gn-Butyl acrylate 70.0 g2-Hydroxyethyl methacrylate 7.0 gMethacrylic acid 4.2 gAcrylamide 2.8 gn-Dodecylmercaptan 0.14 g______________________________________
Example 1-10
Redispersible polymer powder was obtained as in Example 1-4 except that a 5% aqueous solution of hydrochloric acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 1-4.
Example 1-11
Redispersible polymer powder was obtained as in Example 1-4 except that a 5% aqueous solution of acetic acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 1-4.
Example 1-12
Redispersible polymer powder was obtained as in Example 1-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 1-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and their percent water absorptions were measured. The film formed from the redispersible polymer powder of Example 1-12 was lower in percent water absorption and was superior in waterproofness.
Example 1-13
Following the procedures of Example 1-2 except for the replacement of the emulsion composition used in Example 1-1 by that shown in Table 1-4, an aqueous emulsion (C-10) was obtained and redispersible polymer powder was then obtained from the aqueous emulsion.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gButyl acrylate 40.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
Example 1-14
Following the procedures of Example 1-13 except for the replacement of the protective colloid (B-1) by the protective colloid (B-4), an aqueous emulsion (C-11) was obtained and redispersible polymer powder was then obtained from the aqueous emulsion.
Example 1-15
In a reaction vessel equipped with a stirrer, 666.7 g of the protective colloid (B-1) were charged, followed by the addition of 1.0 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above protective colloid at 70.degree. C. over 6 hours, followed by stirring at the same temperature.
______________________________________Purified water 40.0 gSodium lauryl sulfate 0.3 gStyrene 28.0 gButadiene 70.0 gAcrylic acid 2.0 gt-Dodecylmercaptan 0.3 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-12) of 10% solid content and pH 9 was prepared.
When a 5% aqueous solution of sulfuric acid was added at room temperature to 1,000 g of (C-12) until the pH dropped to 2.5, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Comparative Example 1-1
Following the procedures of Example 1-13 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-14) free of the protective colloid (B-1) was obtained. As in Example 1-13, a 5% aqueous solution of sulfuric acid was added until the pH dropped to 2.5. No flocculate was however formed.
Comparative Example 1-2
Following the procedures of Example 1-13 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-14) free of the protective colloid (B-1) was obtained. As in Example 1-13, a 5% aqueous solution of sulfuric acid was added until the pH dropped to 2.5. No flocculate was however formed.
Comparative Example 1-3
Following the procedures of Example 1-15 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-15) free of the protective colloid (B-1) was obtained. As in Example 1-15, a 5% aqueous solution of sulfuric acid was added until the pH dropped to 2.5. No flocculate was however formed.
Comparative Example 1-4
The aqueous emulsions (C-1) to (C-12) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C. instead of subjecting same to flocculation with an acid, whereby redispersible polymer powders were obtained. All the aqueous emulsions formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Evaluation Example 1-1
A yield was calculated in accordance with the following formula:
Yield (%)=[{M2-(M2.times.A/100}/M1].times.100
where
M1: solid weight of an aqueous emulsion,
M2: weight of a flocculate dried at 80.degree. C. after filtration,
A: residual water content (%) of the flocculate.
The yield was ranked in accordance with the following system:
A: 95% or higher
B: 90% (inclusive) to 95% (exclusive)
C: 90% to 30% (both, exclusive)
D: 30% or lower
Evaluation Example 1-2
Each redispersible polymer powder was crushed to a particle size not greater than 1 mm. The thus-crushed redispersible polymer powder was added to a 1% aqueous solution of sodium hydroxide to give a solid content of 10.00%. The resulting mixture was thoroughly stirred for 30 minutes and then left over for 24 hours. A supernatant was collected and to eliminate any undissolved matter, the solution was filtered through a filter cloth of 300 mesh (50 .mu.m) to prepare a redispersion.
However, the redispersible polymer obtained by spray drying in Comparative Example 1-4 had already been in the form of powder, so that it was sifted through a 16-mesh (1 mm) sieve. Using powder of a particle size of 1 mm and smaller, a redispersion was prepared in the same manner as described above.
The external appearance, redispersibility and room-temperature film-forming properties of the redispersion were evaluated as will be described hereinafter.
(i) Redispersibility
The solid content of the redispersion was measured in accordance with JIS K5407.4 (measuring method of residue after heating) and from the solid content so measured, the redispersibility (%) was determined in accordance with the following calculation formula:
Redispersibility (%)
=[Solid content (%) of
redispersion/10.00].times.100
The redispersibility (%) was ranked in accordance with the following system:
A: 100% to 80% (both, inclusive)
B: 80% (exclusive) to 40% (inclusive)
C: 40% (exclusive) to 10% (inclusive)
D: 10% (exclusive) to 0% (inclusive)
(ii) External Appearance
The external appearance of the redispersion was visually measured.
(iii) Room-Temperature Film-Forming Properties
The redispersion was coated on a glass plate and then dried at room temperature for 1 day. The external appearance of the resultant film was visually evaluated and was ranked in accordance with the following system:
A: Film was formed.
B: Film was formed with cracks formed therein.
C: No film was formed.
Evaluation Example 1-3
Redispersible polymer powder was crushed until the plus-sieve residue on an 80-mesh (200-.mu.m) sieve became 5% or less. The resultant powder was mixed in the below-described portion in cement, and the resulting cement mix was tested in mixing time, workability, flexural strength and compression strength.
However, the redispersible polymer obtained by spray drying in Comparative Example 1-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
______________________________________Portland cement 1,000 gToyoura standard sand 2,000 gSolid anti-foaming agent 5 gRedispersible polymer powder 100 g______________________________________
Water was mixed with the above-described dry mix to give a flow value of 170.+-.10 mm. Aging was conducted first at 20.degree. C. and at least 80% R.H. for 2 days and then at 20.degree. C. and 65 R.H. Testing methods will be described below.
(i) Mixing Time
A time required from the addition of water to the dry mix until being mixed into a uniform moisturized form was measured.
(ii) Trowelability
Workability upon conducting surface flattening by a trowel was ranked in accordance with the following system:
A: Excellent
B: Good
C: Average
D: Poor
(iii) Flexural Strength
Samples of 7 days of age and 28 days of age were tested in accordance with JIS A1172.
(iv) Compression Strength
Samples of 7 days of age and 28 days of age were tested in accordance with JIS A1172.
Further, samples obtained without using any redispersible polymer powder were also tested as controls.
The compositions of the protective colloids used in the above Examples and Comparative Examples are presented in Table 1-1, the compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are shown in Table 1-2 to Table 1-4, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 1-5 to Table 1-15.
2. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by core/shell polymerization, with an acid (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 2-1
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, an aqueous solution consisting of 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") was charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at 80.degree. C. for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 400 gn-Butyl acrylate 500 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcrylamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)".
(ii) Step 2 (Shell Polymerization Step)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 222.2 g of the aqueous emulsion (A-1), 647.8 g of purified water and 100.0 g of methacrylamide were charged. The contents were heated to 75.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. After the methacrylamide was completely dissolved, 30.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 75.degree. C. for 7 hours.
As a result, an aqueous emulsion of 20% resin content and pH 9 was obtained. This aqueous emulsion will be designated "C-1".
(iii) Step 3 (Flocculate Forming Step)
When the aqueous emulsion (C-1) was diluted to 10% solid content with purified water and a 5% aqueous solution of sulfuric acid was then added at room temperature to 1,000 g of the thus-diluted aqueous emulsion until the pH dropped to 2.5, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Examples 2-2 to 2-9
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
An aqueous emulsion (A-1) was obtained as in Example 2-1.
(ii) Step 2 (Shell Polymerization Step)
Aqueous emulsions (C-2 to C-9) were each prepared in accordance with its corresponding composition shown in Table 2-2.
(iii) Step 3 (Flocculate Forming Step)
From the aqueous emulsions (C-2 to C-9), redispersible polymer powders were obtained following the procedures of Example 2-1.
Example 2-10
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
Based on the monomer composition shown in Table 2-1, an aqueous emulsion (A-2) of pH 9 and 45% solid content was obtained in the same manner as the aqueous emulsion (A-1).
(ii) Step 2 (Shell Polymerization Step)
An aqueous emulsion (C-10) was prepared in accordance with its corresponding composition shown in Table 2-3.
(iii) Step 3 (Flocculate Forming Step)
From the aqueous emulsion (C-10), redispersible polymer powder was obtained following the procedures of Example 2-1.
Example 2-11
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
An aqueous emulsion (A-2) was obtained as in Example 2-10.
(ii) Step 2 (Shell Polymerization Step)
An aqueous emulsion (C-11) was prepared in accordance with its corresponding composition shown in Table 2-3.
(iii) Step 3 (Flocculate Forming Step)
From the aqueous emulsion (C-11), redispersible polymer powder was obtained following the procedures of Example 2-1.
Example 2-12
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
An aqueous emulsion (A-3) was prepared by the following procedures.
In an autoclave equipped with a stirrer, an aqueous solution consisting of 790 g of purified water, 2 g of sodium laurylsulfate and 1 g of sodium hydrogencarbonate was charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 70.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercapatan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(ii) Step 2 (Shell Polymerization Step)
An aqueous emulsion (C-12) was prepared in accordance with its corresponding composition shown in Table 2-3.
(iii) Step 3 (Flocculate Forming Step)
From the aqueous emulsion (C-12), redispersible polymer powder was obtained following the procedures of Example 2-1.
Example 2-13
Redispersible polymer powder was obtained as in Example 2-4 except that a 5% aqueous solution of hydrochloric acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 2-4.
Example 2-14
Redispersible polymer powder was obtained as in Example 2-4 except that a 5% aqueous solution of acetic acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 2-4.
Example 2-15
Redispersible polymer powder was obtained as in Example 2-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 2-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and the percent water absorptions of the films were measured. The film formed from the redispersible polymer powder of Example 2-15 was lower in percent water absorption and was superior in waterproofness.
Comparative Examples 2-1 to 2-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% solid content with purified water and a 5% aqueous solution of sulfuric acid was then added at room temperature to 1,000 g of the thus-diluted emulsion until its pH dropped to 2.5. No flocculate was however formed from any of the aqueous emulsions.
Comparative Example 2-4
The aqueous emulsions (C-1) to (C-12) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C., whereby redispersible polymer powders were obtained. All the aqueous emulsions formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Evaluation Example 2-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 2-2 to 2-3
From the redispersible polymer powders, redispersions were prepared as in Evaluation Examples 1-2 to 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 2-4 had already been in the form of powder, so that it was sifted through a 16-mesh (1 mm) sieve. Using powder of a particle size of 1 mm and smaller, a redispersion was prepared in the same manner as described above.
The external appearance, redispersibility and room-temperature film-forming properties of each of those redispersions were evaluated by the methods described in Evaluation Example 1-2. Further, cement mixes were prepared and evaluated by the methods described in Evaluation Example 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 2-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
The compositions of the aqueous emulsions prepared in Step 1 and employed in the above Examples and Comparative Examples are shown in Table 2-1, the compositions of the aqueous emulsions prepared in Step 2 and employed in the above Examples and Comparative Examples are presented in Table 2-2 and Table 2-3, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 2-4 to Table 2-13.
3. Examples directed to the flocculation of a mixture of an aqueous emulsion and a protective colloid with an acid (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 3-1
(i) Aqueous Emulsion Preparation Step
An aqueous emulsion (A-1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, an aqueous solution consisting of 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") was charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 400 gn-Butyl acrylate 500 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcrylamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)".
(ii) Protective Colloid Preparation Step
A protective colloid (a1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 850 g of purified water and 100.0 g of methacrylamide were charged. The contents were heated to 75.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. After the methacrylamide was completely dissolved, 30.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 75.degree. C. for 7 hours.
Aqueous ammonia and purified water were then added, whereby a protective colloid (B-1) of 10% resin content and pH 9 was obtained.
(iii) Mixing Step
The aqueous emulsion (A-1) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50.
(iv) Flocculate Forming Step
When the mixture of the aqueous emulsion (A-1) an the protective colloid (B-1), which had been formed in the mixing step, was diluted to 10% resin content with purified water and a 5% aqueous solution of sulfuric acid was then added at room temperature to 1,000 g of the thus-diluted mixture until the pH dropped to 2.5, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Examples 3-2 to 3-9
(i) Aqueous Emulsion Preparation Step
Aqueous emulsions (A-1 to A-3) of the compositions shown in Table 3-1 were prepared as in Example 3-1.
(ii) Protective Colloid Preparation Step
Following the procedures of Example 3-1, protective colloids (B-2 to B-8) were prepared in accordance with their corresponding compositions shown in Table 3-2.
(iii) Mixing Step
The aqueous emulsions (A-1 to A-3) and the protective colloids (B-2 to B-8) were mixed and stirred to give a solid ratio of 50/50 or 70/30.
(iv) Flocculate Forming Step
Following the procedures of Example 3-1, redispersible polymer powders were obtained.
Example 3-10
Redispersible polymer powder was obtained as in Example 3-4 except that a 5% aqueous solution of hydrochloric acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 3-4.
Example 3-11
Redispersible polymer powder was obtained as in Example 3-4 except that a 5% aqueous solution of acetic acid was added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 3-4.
Example 3-12
Redispersible polymer powder was obtained as in Example 3-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 3-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water. The film formed from the redispersible polymer powder of Example 3-12 was found to be superior in waterproofness.
Example 3-13
After the protective colloid (B-1) was mixed and stirred with the aqueous emulsion (A-2) to give a solid ratio of 50/50, redispersible polymer powder was obtained following the procedures of Example 3-1.
Example 3-14
After the protective colloid (B-4) was mixed and stirred with the aqueous emulsion (A-2) to give a solid ratio of 50/50, redispersible polymer powder was obtained following the procedures of Example 3-1.
Example 3-15
(i) Aqueous Emulsion Preparation Step
An aqueous emulsion (A-3) was prepared by the following procedures.
In an autoclave equipped with a stirrer, 790 g of purified water, 2 g of sodium laurylsulfate and 1 g of sodium hydrogencarbonate were charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsified monomer mixture of the below-described composition was prepared. The monomer mixture was added dropwise to the above aqueous solution over 6 hours, followed by aging.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercaptan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(ii) Protective Colloid Preparation Step
A protective colloid (B-1) of the corresponding composition shown in Table 3-2 was prepared by the following the procedures of Example 3-1.
(iii) Mixing Step
The aqueous emulsion (A-3) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50.
(iv) Flocculate Forming Step
Redispersible polymer powder was obtained as in Example 3-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
Comparative Examples 3-1 to 3-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% solid content with purified water and a 5% aqueous solution of sulfuric acid was then added at room temperature to 1,000 g of the thus-diluted emulsion until its pH dropped to 2.5. No flocculate was however formed from any of the aqueous emulsions.
Comparative Example 3-4
Mixtures of the aqueous emulsions and the protective colloids, said mixtures having been prepared in Examples 3-1 to 3-9 and 3-13 to 3-15, were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C., whereby redispersible polymer powders were obtained. All the mixtures formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Evaluation Example 3-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 3-2 to 3-3
From the redispersible polymer powders, redispersions were prepared as in Evaluation Examples 1-2 to 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 2-4 had already been in the form of powder, so that it was sifted through a 16-mesh (1 mm) sieve. Using powder of a particle size of 1 mm and smaller, a redispersion was prepared in the same manner as described above.
The external appearance, redispersibility and room-temperature film-forming properties of each of those redispersions were evaluated by the methods described in Evaluation Example 1-2. Further, cement mixes were prepared and evaluated by the methods described in Evaluation Example 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 3-4 had already been in the form of powder, so that it was sifted through a 16-mesh (1 mm) sieve. Using powder of a particle size of 1 mm and smaller, a redispersion was prepared in the same manner as described above.
The compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are shown in Table 3-1, the compositions of the protective colloids employed in the above Examples and Comparative Examples are presented in Table 3-2, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 3-3 to Table 3-14.
4. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by protective colloidal polymerization, with a metal salt (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 4-1
(1) Step 1 (Aqueous Emulsion Preparation Step)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785.0 g of purified water and 150.0 g of methacrylamide were charged. Under stirring in a nitrogen gas atmosphere, the contents were heated to 75.degree. C. and were maintained at the same temperature. After the methacrylamide was completely dissolved, 45.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 75.degree. C. for 7 hours to obtain an aqueous solution. Aqueous ammonia and purified water were added to the aqueous solution, whereby a protective colloid (B-1) of 15% resin content and pH 9 was obtained.
Protective Colloid Polymerization
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 666.7 g of the protective colloid (B-1) were charged, followed by the addition of 0.5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by stirring at the same temperature for 3 hours.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gStyrene 40.0 gn-Butyl acrylate 50.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-1) of 10% resin content and pH 9 was prepared.
(2) Step 2 (Flocculate Forming Step)
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-1), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less [note: Each residual water content will hereinafter mean a value measured by this method). The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Examples 4-2 to 4-8
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
Following the procedures of Example 4-1, protective colloids (B-2) to (B-8) were prepared in accordance with their corresponding compositions shown in Table 4-1.
Protective Colloid Polymerization
Aqueous emulsions (C-2) to (C-8) were obtained following the procedures of Example 4-1 except that the protective colloid (B-1) in Example 4-1 was replaced by the protective colloids (B-2) to (B-8), respectively.
(2) Step 2 (Flocculate Forming Step)
Redispersible polymer powders were obtained following the procedures of Example 4-1 except that the aqueous emulsion (C-1) in Example 4-1 was replaced by the aqueous emulsions (C-2) to (C-8).
Example 4-9
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
Following the procedures of Example 4-1, a protective colloid (B-1) was prepared.
Protective Colloid Polymerization
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 400.0 g of the protective colloid (B-1) and 210 g of purified water were charged, followed by the addition of 0.7 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 3 hours, followed by aging for 3 hours.
______________________________________Purified water 56.0 gSodium dodecylbenzenesulfonate 0.14 gStyrene 56.0 gn-Butyl acrylate 70.0 g2-Hydroxyethyl methacrylate 7.0 gMethacrylic acid 4.2 gAcrylamide 2.8 gn-Dodecylmercaptan 0.14 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-9) of 10% resin content and pH 9 was prepared.
(2) Step 2 (Flocculate Forming Step)
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-9), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Example 4-10
Redispersible polymer powder was obtained as in Example 4-4 except that 225 g of a 10% aqueous solution of ferric sulfate were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 4-4.
Example 4-11
Redispersible polymer powder was obtained following the procedures of Example 4-4 except that the 45% aqueous solution of aluminum sulfate was added after the temperature of the aqueous emulsion was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 4-4, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 4-12
Redispersible polymer powder was obtained following the procedures of Example 4-4 except that 225 g of a 10% aqueous solution of calcium chloride were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 4-4.
Example 4-13
Redispersible polymer powder was obtained following the procedures of Example 4-12 except that the pH of the aqueous emulsion was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 4-12, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 4-14
Redispersible polymer powder was obtained as in Example 4-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 4-15
Redispersible polymer powder was obtained as in Example 4-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 4-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and their percent water absorptions were measured. The film formed from the redispersible polymer powder of Example 4-15 was lower in percent water absorption and was superior in waterproofness.
Example 4-16
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
Following the procedures of Example 4-1, a protective colloid (B-1) was prepared.
Protective Colloid Polymerization
Following the procedures of Example 4-1 except that the emulsion employed there was modified as will be described below, an aqueous emulsion (C-10) was obtained and from the aqueous emulsion, redispersible polymer powder was obtained.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gMethyl methacrylate 50.0 gButyl acrylate 40.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
(2) Step 2 (Flocculate Forming Step)
Redispersible polymer powder was obtained as in Example 4-1.
Example 4-17
Following the procedures of Example 4-16 except that the protective colloid (B-1) was changed to the protective colloid (B-4), an aqueous emulsion (C-11) was obtained and from the aqueous emulsion, redispersible polymer powder was obtained.
Example 4-18
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
Following the procedures of Example 4-1, a protective colloid (B-1) was prepared.
Protective Colloid Polymerization
In an autoclave equipped with a stirrer, 666.7 g of the protective colloid (B-1) were charged, followed by the addition of 1.0 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 6 hours, followed by aging.
______________________________________Purified water 40.0 gSodium lauryl sulfate 0.3 gStyrene 28.0 gButadiene 70.0 gAcrylic acid 2.0 gt-Dodecylmercaptan 0.3 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-12) of 10% solid content and pH 9 was prepared.
(2) Step 2 (Flocculate Forming Step)
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-12), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Comparative Example 4-1
Following the procedures of Example 4-1 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-13) free of the protective colloid (B-1) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 4-2
Following the procedures of Example 4-16 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-14) free of the protective colloid (B-1) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 4-3
Following the procedures of Example 4-18 except that the protective colloid (B-1) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-15) free of the protective colloid (B-1) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 4-4
The aqueous emulsions (C-1) to (C-12) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 600.degree. C. instead of subjecting to flocculation with any metal salt, whereby redispersible polymer powders were obtained. All the aqueous emulsions formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 4-5
It was attempted to obtain redispersible polymer powder as in Example 4-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 4-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 4-2
The redispersible polymer powders were evaluated as in Evaluation Example 1-2.
Evaluation Example 4-3
Evaluation was conducted as in Evaluation Example 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 4-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
The compositions of the protective colloids used in the above Examples and Comparative Examples are presented in Table 4-1, the compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are shown in Table 4-2 to Table 4-4, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 4-5 to Table 4-13.
5. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by core/shell polymerization, with a metal salt (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 5-1
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") were charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 400 gn-Butyl acrylate 500 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcrylamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)".
(ii) Step 2 (Shell Polymerization Step)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 222.2 g of the aqueous emulsion (A-1), 647.8 g of purified water and 100.0 g of methacrylamide were charged. The contents were heated to 75.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. After the methacrylamide was completely dissolved, 30.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 750.degree. C. for 7 hours.
As a result, an aqueous emulsion of 20% resin content and pH 9 was obtained. This aqueous emulsion will be designated "C-1".
(iii) Step 3 (Flocculate Forming Step)
When the aqueous emulsion (C-1) was diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate were then added at room temperature to 1,000 g of the thus-diluted aqueous emulsion, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less [note: The residual water content was measured by the measuring method of weight loss on heating prescribed under JIS K5407.5. Each residual water content will hereinafter mean a value measured by this method]. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Examples 5-2 to 5-12
(1) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
i) Preparation of Aqueous Emulsion (A-1)
Following the procedures of Example 5-1, an aqueous emulsion (A-1) was prepared.
ii) Preparation of Aqueous Emulsion (A-2)
Following the procedures of the preparation process of the aqueous emulsion (A-1) shown in Example 5-1, an aqueous emulsion (A-2) of pH 9 and 45% resin content was obtained in accordance with its corresponding monomer composition shown in Table 5-1.
iii) Preparation of Aqueous Emulsion (A-3)
In an autoclave equipped with a stirrer, an aqueous solution consisting of 790 g of purified water, 2 g of sodium lauryl sulfate and 1 g of sodium hydrogencarbonate was charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 70.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercaptan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(2) Step 2 (Shell Polymerization Step)
Following the procedures of Example 5-1, aqueous emulsions (C-2) to (C-12) were prepared in accordance with their corresponding compositions shown in Table 5-2 and Table 5-3.
(3) Step 3 (Flocculate Forming Step)
From the aqueous emulsions (C-2) to (C-12), redispersible polymer powders were obtained, respectively, following the procedures of Example 5-1.
Example 5-13
Redispersible polymer powder was obtained as in Example 5-4 except that 225 g of a 10% aqueous solution of ferric sulfate were added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 5-4.
Example 5-14
Redispersible polymer powder was obtained following the procedures of Example 5-4 except that a 45% aqueous solution of sulfuric acid was added after the temperature of the aqueous emulsion was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 5-4, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 5-15
Redispersible polymer powder was obtained following the procedures of Example 5-4 except that 225 g of a 10% aqueous solution of calcium chloride were added instead of the 45% aqueous solution of aluminum sulfate used for obtaining the flocculate in Example 5-4.
Example 5-16
Redispersible polymer powder was obtained following the procedures of Example 5-15 except that the pH of the aqueous emulsion was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 5-15, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 5-17
Redispersible polymer powder was obtained as in Example 5-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 5-18
Redispersible polymer powder was obtained as in Example 5-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 5-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and the percent water absorptions of the films were measured. The film formed from the redispersible polymer powder of Example 5-18 was lower in percent water absorption and was superior in waterproofness.
Comparative Examples 5-1 to 5-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate was then added at room temperature to 1,000 g of the thus-diluted emulsion. Each of the aqueous emulsions formed a flocculate. The flocculate was subjected to solid-liquid separation by filtration and was then dried at 80.degree. C. until its residual water content dropped to 2% or lower. The flocculates so dried were however all soft so that their crushing was impossible. Evaluations of redispersibility was therefore conducted without crushing.
Comparative Example 5-4
The aqueous emulsions (C-1) to (C-12) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C., whereby redispersible polymer powders were obtained. All the aqueous emulsions formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 5-5
It was attempted to obtain redispersible polymer powder as in Example 5-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 5-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 5-2
From the redispersible polymer powders, redispersions were prepared as in Evaluation Example 1-2.
However, the redispersible polymers of Comparative Examples 5-1 to 5-3 were all so soft that their crushing was impossible. Redispersions were prepared from them in a manner similar to the above-mentioned manner except that they were not crushed.
Further, the redispersible polymer obtained by spray drying in Comparative Example 5-4 had already been in the form of powder, so that it was sifted through a 16-mesh (1 mm) sieve. Using powder of a particle size of 1 mm and smaller, a redispersion was prepared in the same manner as described above and was evaluated as described in Evaluation Example 4-2.
Evaluation Example 5-3
The redispersible polymer powders were tested as in Evaluation Example 1-3.
However, the redispersible polymer obtained by spray drying in Comparative Example 5-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
The compositions of the aqueous emulsions prepared in Step 1 and employed in the above Examples and Comparative Examples are shown in Table 5-1, the compositions of the aqueous emulsions prepared in Step 2 and employed in the above Examples and Comparative Examples are presented in Table 5-2 and Table 5-3, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 5-4 to Table 5-15.
6. Examples directed to the flocculation of a mixture of an aqueous emulsion and a protective colloid with a metal salt (a system making use of an amido-containing ethylenically unsaturated monomer).
Example 6-1
(i) Aqueous Emulsion Preparation Step
An aqueous emulsion (A-1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") were charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 400 gn-Butyl acrylate 500 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcrylamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)".
(ii) Protective Colloid Preparation Step
A protective colloid (a1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 850 g of purified water and 100.0 g of methacrylamide were charged. The contents were heated to 75.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. After the methacrylamide was completely dissolved, 30.0 g of a 5% aqueous solution of ammonium persulfate were added and the resultant mixture was maintained at 75.degree. C. for 7 hours.
Aqueous ammonia and purified water were then added, whereby a protective colloid (B-1) of 10% resin content and pH 9 was obtained.
(iii) Mixing Step
The aqueous emulsion (A-1) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50.
(iv) Flocculate Forming Step
When the mixture of the aqueous emulsion (A-1) an the protective colloid (B-1), which had been formed in the mixing step, was diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate were then added at room temperature to 1,000 g of the thus-diluted mixture, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Examples 6-2 to 6-8
(1) Aqueous Emulsion Preparation Step
i) Preparation of Aqueous Emulsion (A-1)
As in Example 6-1, an aqueous emulsion (A-1) was prepared.
ii) Preparation of Aqueous Emulsion (A-2)
In the same manner as the preparation process of the aqueous emulsion (A-1) shown in Example 6-1, an aqueous emulsion (A-2) of pH 9 and 45% resin content was obtained in accordance with its corresponding monomer composition shown in Table 6-1.
iii) Preparation of Aqueous Emulsion (A-3)
In an autoclave equipped with a stirrer, 790 g of purified water, 2 g of sodium lauryl sulfate and 1 g of sodium hydrogencarbonate were charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere to prepare an aqueous solution. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 6 hours, followed by aging.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercaptan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(2) Protective Colloid Preparation Step
Protective colloids (B-2 to B-8) were prepared following the procedures of Example 6-1.
(3) Mixing Step
The protective colloids (B-2 to B-8) were each mixed and stirred with the aqueous emulsion (A-1) to give a solid ratio of 50/50.
(4) Flocculate Forming Step
Following the procedures of Example 6-1, redispersible polymer powders were obtained.
Example 6-9
After the aqueous emulsion (A-1) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 70/30, the procedures of Example 6-1 were followed so that redispersible polymer powder was obtained.
Example 6-10
Redispersible polymer powder was obtained as in Example 6-4 except that 225 g of a 10% aqueous solution of ferric sulfate were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 6-4.
Example 6-11
Redispersible polymer powder was obtained following the procedures of Example 6-4 except that the 45% aqueous solution of aluminum sulfate was added after the temperature of the mixture of the aqueous emulsion and the protective colloid was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 6-4, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 6-12
Redispersible polymer powder was obtained following the procedures of Example 6-4 except that 225 g of a 10% aqueous solution of calcium chloride were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 6-4.
Example 6-13
Redispersible polymer powder was obtained following the procedures of Example 6-12 except that the pH of the mixture of the aqueous emulsion and the protective colloid was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 6-12, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 6-14
Redispersible polymer powder was obtained as in Example 6-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 6-15
Redispersible polymer powder was obtained as in Example 6-4 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 6-4 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and their percent water absorptions were measured. The film formed from the redispersible polymer powder of Example 6-15 was lower in percent water absorption and was superior in waterproofness.
Example 6-16
After the aqueous emulsion (A-2) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 6-1 were followed so that redispersible polymer powder was obtained.
Example 6-17
After the aqueous emulsion (A-2) and the protective colloid (B-4) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 6-1 were followed so that redispersible polymer powder was obtained.
Example 6-18
After the aqueous emulsion (A-3) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 6-1 were followed so that redispersible polymer powder was obtained.
Comparative Examples 6-1 to 6-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate was then added at room temperature to 1,000 g of the thus-diluted emulsion. Each of the aqueous emulsions formed a flocculate. The flocculate was subjected to solid-liquid separation by filtration and was then dried at 80.degree. C. until its residual water content dropped to 2% or lower. The flocculates so dried were however all soft so that their crushing was impossible. Evaluations of redispersibility was therefore conducted without crushing.
Comparative Example 6-4
Mixtures of the aqueous emulsions and the protective colloids, said mixtures having been prepared in Examples 6-1 to 6-9 and 6-16 to 6-18, were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C. instead of subjecting them to flocculation with any metal salt, whereby redispersible polymer powders were obtained.
All the mixtures formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 6-5
It was attempted to obtain redispersible polymer powder as in Example 6-4 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 6-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 6-2
The redispersible polymer powders were evaluated as in Evaluation Example 1-2.
Evaluation Example 6-3
As in Evaluation Example 1-3, redispersible polymer powders were mixed in cement and the resulting cement mixes were tested.
However, the redispersible polymer obtained by spray drying in Comparative Example 6-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
The compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are shown in Table 6-1, the compositions of the protective colloids employed in the above Examples and Comparative Examples are presented in Table 6-2, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 6-3 to Table 6-14.
7. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by protective colloidal polymerization, with a metal salt (a system making use of a hydroxyl-containing ethylenically unsaturated monomer).
Example 7-1
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 700.0 g of a 1.5% aqueous solution of sodium hydroxide, 90.0 g of 2-hydroxyethyl methacrylate and 10.0 g of methacrylic acid were charged. Under stirring in a nitrogen gas atmosphere, the contents were heated to 40.degree. C. When this temperature remained unchanged, 10.0 g of potassium persulfate were added. After the potassium persulfate was completely dissolved, 25.6 g of a 15% aqueous solution of sodium hydrogensulfite were added further as a reducing agent and the resultant mixture was maintained at 40.degree. C. for 6 hours to prepare an aqueous solution.
______________________________________1.5% Aq. soln. of NaOH 700.0 g2-Hydroxyethyl methacrylate 90.0 gMethacrylic acid 10.0 gPotassium persulfate 10.0 g15% Aq. soln. of NaHSO.sub.3 25.6 g______________________________________
A colloid (B-1) of 15% resin content and pH 9 was obtained.
Protective Colloid Polymerization
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 666.7 g of the protective colloid (B-1) were charged, followed by the addition of 0.5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above protective colloid at 80.degree. C. over 3 hours, and the resultant mixture was maintained at the same temperature for 3 hours.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gStyrene 50.0 gn-Butyl acrylate 40.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-1) of 10% resin content and pH 9 was prepared. The particle size of this aqueous emulsion (C-1) was 0.18 .mu.m.
(2) Step 2 (Flocculate Forming Step)
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-1), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less [note: The residual water content was measured by the measuring method of weight loss on heating prescribed under JIS K5407.5. Each residual water content will hereinafter mean a value measured by this method). The thus-dried flocculate was crushed and sifted through a 50-mesh (300-.mu.m) sieve, whereby redispersible polymer powder of 300 .mu.m and smaller in particle size was obtained. Its bulk specific gravity was 670 g/l.
Examples 7-2 to 7-7
(1) Step 1 (Aqueous Emulsion Preparation Step)
Preparation of Protective Colloid (a1)
Following the procedures of Example 7-1, protective colloids (B-2) to (B-7) were prepared in accordance with their corresponding compositions shown in Table 7-1.
Protective Colloid Polymerization
Aqueous emulsions (C-2) to (C-7) were obtained following the procedures of Example 7-1 except that the protective colloid (B-1) in Example 7-1 was replaced by the protective colloids (B-2) to (B-7), respectively.
(2) Step 2 (Flocculate Forming Step)
Redispersible polymer powders were obtained following the procedures of Example 7-1 except that the aqueous emulsion (C-1) in Example 7-1 was replaced by the aqueous emulsions (C-2) to (C-7).
Example 7-8
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 400.0 g of the protective colloid (B-2) and 210 g of purified water were charged, followed by the addition of 0.7 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 3 hours, followed by aging for 3 hours.
______________________________________Purified water 56.0 gSodium dodecylbenzenesulfonate 0.14 gStyrene 70.0 gn-Butyl acrylate 56.0 g2-Hydroxyethyl methacrylate 7.0 gMethacrylic acid 4.2 gAcrylamide 2.8 gn-Dodecylmercaptan 0.14 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-8) of 10% resin content and pH 9 was prepared.
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-8), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Example 7-9
Redispersible polymer powder was obtained as in Example 7-2 except that 225 g of a 10% aqueous solution of ferric sulfate were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 7-2.
Example 7-10
Redispersible polymer powder was obtained following the procedures of Example 7-2 except that the 45% aqueous solution of aluminum sulfate was added after the temperature of the aqueous emulsion was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 7-2, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 7-11
Redispersible polymer powder was obtained following the procedures of Example 7-2 except that 225 g of a 10% aqueous solution of calcium chloride were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 7-2.
Example 7-12
Redispersible polymer powder was obtained following the procedures of Example 7-11 except that the pH of the aqueous emulsion was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 7-11, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 7-13
Redispersible polymer powder was obtained as in Example 7-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 7-14
Redispersible polymer powder was obtained as in Example 7-2 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 7-2 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and their percent water absorptions were measured. The film formed from the redispersible polymer powder of Example 7-14 was lower in percent water absorption and was superior in waterproofness.
Example 7-15
Following the procedures of Example 7-1 except that the emulsion employed there was modified as will be described below, an aqueous emulsion (C-9) was obtained and from the aqueous emulsion, redispersible polymer powder was obtained.
______________________________________Purified water 40.0 gSodium dodecylbenzenesulfonate 0.1 gMethyl methacrylate 30.0 gButyl acrylate 60.0 g2-Hydroxyethyl methacrylate 5.0 gMethacrylic acid 3.0 gAcrylamide 2.0 gn-Dodecylmercaptan 0.1 g______________________________________
Example 7-16
Following the procedures of Example 7-15 except that the protective colloid (B-1) was changed to the protective colloid (B-2), an aqueous emulsion (C-10) was obtained and from the aqueous emulsion, redispersible polymer powder was obtained.
Example 7-17
In an autoclave equipped with a stirrer, 666.7 g of the protective colloid (B-2) were charged, followed by the addition of 1.0 g of potassium persulfate at 700.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 6 hours, followed by aging.
______________________________________Purified water 40.0 gSodium lauryl sulfate 0.3 gStyrene 28.0 gButadiene 70.0 gAcrylic acid 2.0 gt-Dodecylmercaptan 0.3 g______________________________________
Aqueous ammonia and purified water were added to the resultant polymer, whereby an aqueous emulsion (C-11) of 10% solid content and pH 9 was prepared.
When 50 g of a 45% aqueous solution of aluminum sulfate were added at room temperature to 1,000 g of (C-11), a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
Comparative Example 7-1
Following the procedures of Example 7-2 except that the protective colloid (B-2) was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-12) free of the protective colloid (B-2) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 7-2
Following the procedures of Example 7-2 except that the protective colloid (B-2) employed in Example 7-13 was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-13) free of the protective colloid (B-2) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 7-3
Following the procedures of Example 7-16 except that the protective colloid (B-2) employed in Example 7-14 was replaced by 650.0 g of purified water, an aqueous emulsion polymer (C-14) free of the protective colloid (B-2) was obtained. It was then attempted to obtain redispersible polymer powder from the aqueous emulsion polymer. However, a flocculate obtained after drying was so soft that its crushing was impossible. Evaluation of its redispersibility was therefore conducted without crushing.
Comparative Example 7-4
The aqueous emulsions (C-1) to (C-11) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C. instead of subjecting them to flocculation with any metal salt, whereby redispersible polymer powders were obtained. All the mixtures formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 7-5
It was attempted to obtain redispersible polymer powder as in Example 7-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 7-1
The weights of the solid contents of the aqueous emulsions were measured as in Evaluation Example 1-1.
Evaluation Example 7-2
The redispersible polymer powders were evaluated as in Evaluation Example 1-2.
Evaluation Example 7-3
As in Evaluation Example 1-3, the redispersible polymer powders were mixed in cement and the resulting cement mixes were tested.
However, the redispersible polymer obtained by spray drying in Comparative Example 7-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
Evaluation Example 7-4
The polymer powder obtained in Example 7-4 was mixed with Portland cement and water in accordance with the below-described composition. The resulting concrete was aged at 20.degree. C. and 80% R.H. (relative humidity), whereby its smell and hardening were evaluated.
______________________________________<Composition>______________________________________Portland cement 1,000 gRedispersible polymer powder 100 gWater 500 g______________________________________
Evaluation
Smell: one day later, the existence or non-existence of ammonia smell was determined.
Hardening: By the setting test prescribed under JIS R5201, it was determined whether setting had been completed or not after one-day aging.
Results
Smell: Not sensed.
Hardening: Setting had been completed.
Evaluation Example 7-5
Evaluation of Redispersibility under the Assumption of Emulsification in Cement
Evaluation of redispersibility was conducted by the following method.
1. Cement (100 g) and water (500 g) were mixed for 1 minute and then filtered through filter paper ("Qualitative Filter Paper No. 1", trade name; product of Advantec Toyo Kaisha, Ltd.), whereby a filtrate was obtained.
2. In a 100-ml Erlenmeyer flask, 94 g of the filtrate were sampled, with which 3 g of calcium hydroxide (powder) were mixed.
3. The above mixture was added with 3 g of resin powder of 300 .mu.m and smaller in diameter which had been crushed and sifted.
4. Three minutes later, the resultant mixture was filtered through filter paper ("Qualitative Filter Paper No. 1", trade name; product of Advantec Toyo Kaisha, Ltd.), whereby a filtrate was obtained. The non-volatile content of the filtrate was measured in accordance with the method prescribed under JIS K5407.4 This non-volatile content will be designated "N1 (wt. %)".
5. The mixture prepared above in step 2 was filtered as in step 4 and the non-volatile content of the filtrate was measured. This non-volatile content will be designated "N2 (wt. %)".
6. Redispersibility (%) was measured by the following formula: ##EQU1##
The above redispersibility (%) of the polymer powder obtained in Example 7-2 was 40% or higher and was hence good. On the other hand, the redispersibility of the polymer powder obtained by spray drying the polymer of Example 7-2 was 15% or lower and was hence poor.
The compositions of the protective colloids employed in the above Examples and Comparative Examples are shown in Table 7-1, the compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are presented in Table 7-2 and Table 7-3, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 7-4 to Table 7-5.
8. Examples directed to the flocculation of an aqueous emulsion, which had been prepared by core/shell polymerization, with an acid (a system making use of a hydroxyl-containing ethylenically unsaturated monomer).
Example 8-1
(i) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") were charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 500 gn-Butyl acrylate 400 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcryiamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)". The particle size of the aqueous emulsion (A-1) was 0.11 .mu.m.
(ii) Step 2 (Shell Polymerization Step)
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 725.0 g of purified water, 90.0 g of 2-hydroxyethyl methacrylate and 10.0 g of methacrylic acid were charged. The contents were adjusted to pH 9.5 with sodium hydroxide. The contents were then heated to 40.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. Potassium persulfate (10.0 g) was added. Subsequent to dissolution of potassium persulfate, 38.4 g of an 10% aqueous solution of sodium hydrogensulfite were added further and the resulting mixture was maintained at 40.degree. C. for 6 hours.
______________________________________Aqueous emulsion polymer (A-1) 222.2 gPurified water 725.0 g2-Hydroxyethyl methacrylate 90.0 gMethacrylic acid 10.0 gSodium hydroxide 6.6 gPotassium persulfate 10.0 g10% Aq. soln. of NaHSO.sub.3 38.4 g______________________________________
As a result, an aqueous emulsion of 20% resin content and pH 8 was obtained. This aqueous emulsion will be designated "(C-1)". The particle size of this aqueous emulsion (C-1) was 0.13 .mu.m.
(iii) Step 3 (Flocculate Forming Step)
When the aqueous emulsion (C-1) was diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate were then added at room temperature to 1,000 g of the thus-diluted aqueous emulsion, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained. The thus-dried flocculate was crushed and sifted through a 50-mesh (300-.mu.m) sieve, whereby redispersible polymer powder of 300 .mu.m and smaller in particle size was obtained. Its bulk specific gravity was 640 g/l.
Examples 8-2 to 8-11
(1) Step 1 (Core Particle Polymerization Step--Preparation of Aqueous Emulsion)
i) Preparation of Aqueous Emulsion (A-1)
Following the procedures of Example 8-1, an aqueous emulsion (A-1) was prepared.
ii) Preparation of Aqueous Emulsion (A-2)
Following the procedures of the preparation process of the aqueous emulsion (A-1) shown in Example 8-1, an aqueous emulsion (A-2) of pH 9 and 45% resin content was obtained in accordance with its corresponding monomer composition shown in Table 8-1.
iii) Preparation of Aqueous Emulsion (A-3)
In an autoclave equipped with a stirrer, an aqueous solution consisting of 790 g of purified water, 2 g of sodium lauryl sulfate and 1 g of sodium hydrogencarbonate was charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 70.degree. C. over 6 hours, followed by maintenance at the same temperature for 6 hours.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercaptan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(2) Step 2 (Shell Polymerization Step)
Following the procedures of Example 8-1, aqueous emulsions (C-2) to (C-11) were prepared in accordance with their corresponding compositions shown in Table 8-2 and Table 8-3.
(3) Step 3 (Flocculate Forming Step)
From the aqueous emulsions (C-2) to (C-12), redispersible polymer powders were obtained, respectively, following the procedures of Example 8-1.
Example 8-12
Redispersible polymer powder was obtained as in Example 8-2 except that 225 g of a 10% aqueous solution of ferric sulfate were added instead of the 5% aqueous solution of sulfuric acid employed for obtaining the flocculate in Example 8-2.
Example 8-13
Redispersible polymer powder was obtained following the procedures of Example 8-2 except that a 45% aqueous solution of sulfuric acid was added after the temperature of the aqueous emulsion was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 8-2, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 8-14
Redispersible polymer powder was obtained following the procedures of Example 8-2 except that 225 g of a 10% aqueous solution of calcium chloride were added instead of the 45% aqueous solution of aluminum sulfate used for obtaining the flocculate in Example 8-2.
Example 8-15
Redispersible polymer powder was obtained following the procedures of Example 8-14 except that the pH of the aqueous emulsion was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 8-17, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 8-16
Redispersible polymer powder was obtained as in Example 8-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 8-17
Redispersible polymer powder was obtained as in Example 8-2 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 8-2 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day and the percent water absorptions of the films were measured. The film formed from the redispersible polymer powder of Example 8-17 was lower in percent water absorption and was superior in waterproofness.
Comparative Examples 8-1 to 8-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate was then added at room temperature to 1,000 g of the thus-diluted emulsion. Each of the aqueous emulsions formed a flocculate. The flocculate was subjected to solid-liquid separation by filtration and was then dried at 80.degree. C. until its residual water content dropped to 2% or lower. The flocculates so dried were however all soft so that their crushing was impossible. Evaluations of redispersibility was therefore conducted without crushing.
Comparative Example 8-4
The aqueous emulsions (C-1) to (C-11) were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C., whereby redispersible polymer powders were obtained. All the aqueous emulsions formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 8-5
It was attempted to obtain redispersible polymer powder as in Example 8-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 8-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 8-2
The redispersible polymer powders were evaluated as in Evaluation Example 1-2.
Evaluation Example 8-3
As in Evaluation Example 1-3, the redispersible polymer powders were mixed in cement and the resulting cement mixes were tested.
However, the redispersible polymer obtained by spray drying in comparative Example 8-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
Evaluation Example 8-4
With respect to the polymer powder obtained in Example 7-4, smell and hardening were determined.
Results
Smell: Not sensed.
Hardening: Setting had been completed.
Evaluation Example 8-5
Evaluation of Redispersibility under the Assumption of Emulsification in Cement
Evaluation of redispersibility was conducted in the same manner as in Evaluation Example 7-5.
The above redispersibility (%) of the polymer powder obtained in Example 8-2 was 40% or higher and was hence good. On the other hand, the redispersibility of the polymer powder obtained by spray drying the polymer of Example 8-2 was 15% or lower and was hence poor.
The compositions of the protective colloids prepared in Step 1 and employed in the above Examples and Comparative Examples are shown in Table 8-1, the compositions of the aqueous emulsions prepared in Step 2 and employed in the above Examples and Comparative Examples are presented in Table 8-2 and Table 8-3, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 8-4 to Table 8-15.
9. Examples directed to the flocculation of a mixture of an aqueous emulsion and a protective colloid with a metal salt (a system making use of a hydroxyl-containing ethylenically unsaturated monomer).
Example 9-1
(i) Aqueous Emulsion Preparation Step
An aqueous emulsion (A-1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 785 g of purified water and 3 g of sodium dodecylbenzenesulfonate (abbreviated as "DBS") were charged, followed by the addition of 5 g of potassium persulfate at 80.degree. C. under stirring in a nitrogen gas atmosphere. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution at 80.degree. C. over 3 hours, followed by maintenance at the same temperature for 3 hours.
______________________________________Purified water 400 gDBS 1 gStyrene 500 gn-Butyl acrylate 400 g2-Hydroxyethyl methacrylate 50 gMethacrylic acid 30 gAcrylamide 20 gn-Dodecylmercaptan 1 g______________________________________
Aqueous ammonia and purified water were added to the resultant aqueous emulsion to adjust its pH and resin content to 9 and 45%, respectively. This aqueous emulsion will be designated "(A-1)". The particle size of the aqueous emulsion (A-1) was 0.11 .mu.m.
(ii) Protective Colloid Preparation Step
A protective colloid (a1) was prepared by the following procedures.
In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 700.0 g of a 1.5% aqueous solution of sodium hydroxide, 90.0 g of 2-hydroxyethyl methacrylate and 10.0 g of methacrylic acid were charged. The contents were then heated to 40.degree. C. under stirring in a nitrogen gas atmosphere and were maintained at the same temperature. Potassium persulfate (10.0 g) was added. Subsequent to dissolution of potassium persulfate, 25.6 g of an 15% aqueous solution of sodium hydrogensulfite were added further as a reducing agent and the resulting mixture was maintained at 40.degree. C. for 6 hours.
______________________________________1.5% Aq. soln. of NaOH 700.0 g2-Hydroxyethyl methacrylate 90.0 gMethacrylic acid 10.0 gPotassium persulfate 10.0 g15% Aq. soln. of NaHSO.sub.3 25.6 g______________________________________
Purified water was added to the thus-obtained mixture, whereby a protective colloid (B-1) of 10% resin content and pH 5 was obtained.
(iii) Mixing Step
The aqueous emulsion (A-1) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50.
(iv) Flocculate Forming Step
When the mixture of the aqueous emulsion (A-1) an the protective colloid (B-1), which had been formed in the mixing step, was diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate were then added at room temperature to 1,000 g of the thus-diluted mixture, a flocculate was formed. The flocculate was subjected to solid-liquid separation by filtration, and was then dried at 80.degree. C. until the residual water content dropped to 2% or less. The thus-dried flocculate was crushed, whereby redispersible polymer powder was obtained.
The thus-dried flocculate was crushed and sifted through a 50-mesh (300-.mu.m) sieve, whereby redispersible polymer powder of 300 .mu.m and smaller in particle size was obtained. Its bulk specific gravity was 605 g/l.
Examples 9-2 to 9-7
(1) Aqueous Emulsion Preparation Step
i) Preparation of Aqueous Emulsion (A-1)
As in Example 9-1, an aqueous emulsion (A-1) was prepared.
ii) Preparation of Aqueous Emulsion (A-2)
In the same manner as the preparation process of the aqueous emulsion (A-1) shown in Example 9-1, an aqueous emulsion (A-2) of pH 9 and 45% resin content was obtained in accordance with its corresponding monomer composition shown in Table 9-1.
iii) Preparation of aqueous emulsion (A-3)
In an autoclave equipped with a stirrer, 790 g of purified water, 2 g of sodium laurylsulfate and 1 g of sodium hydrogencarbonate were charged, followed by the addition of 10 g of potassium persulfate at 70.degree. C. under stirring in a nitrogen gas atmosphere to prepare an aqueous solution. On the side, an emulsion of the below-described composition was prepared. The emulsion was added dropwise to the above aqueous solution over 6 hours and was maintained at the same temperature for 6 hours.
______________________________________Purified water 400 gSodium lauryl sulfate 3 gStyrene 280 gButadiene 700 gAcrylic acid 20 gt-Dodecylmercaptan 3 g______________________________________
Aqueous ammonia and purified water were added to the thus-obtained SBR latex, whereby an aqueous emulsion (A-3) of pH 9 and 45% solid content was prepared.
(2) Protective Colloid Preparation Step
Protective colloids (B-2) to (B-7) were prepared following the procedures of Example 9-1.
(3) Mixing Step
The protective colloids (B-2) to (B-8) were each mixed and stirred with the aqueous emulsion (A-1) to give a solid ratio of 50/50.
(4) Flocculate Forming Step
Following the procedures of Example 9-1, redispersible polymer powders were obtained.
Example 9-8
After the aqueous emulsion (A-1) and the protective colloid (B-2) were mixed and stirred to give a solid ratio of 70/30, the procedures of Example 9-2 were followed so that redispersible polymer powder was obtained.
Example 9-9
Redispersible polymer powder was obtained as in Example 9-2 except that 225 g of a 10% aqueous solution of ferric sulfate were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 9-2.
Example 9-10
Redispersible polymer powder was obtained following the procedures of Example 9-2 except that the 45% aqueous solution of aluminum sulfate was added after the temperature of the mixture of the aqueous emulsion and the protective colloid was raised to 70.degree. C. Flocculate lumps so obtained were greater than those obtained in Example 9-2, so that the solid-liquid separation time by filtration was shortened to 1/10 and the workability was improved.
Example 9-11
Redispersible polymer powder was obtained following the procedures of Example 9-2 except that 225 g of a 10% aqueous solution of calcium chloride were added in place of the 45% aqueous solution of aluminum sulfate employed for obtaining the flocculate in Example 9-2.
Example 6-12
Redispersible polymer powder was obtained following the procedures of Example 9-11 except that the pH of the mixture of the aqueous emulsion and the protective colloid was adjusted to 4 with sulfuric acid before the addition of a metal salt and 225 g of a 10% aqueous solution of calcium chloride were added as the metal salt. Flocculate lumps so obtained were greater than those obtained in Example 9-11, so that the solid-liquid separation time by filtration was shortened to 1/3 and the workability was improved.
Example 9-13
Redispersible polymer powder was obtained as in Example 9-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 6.5 g.
Example 9-14
Redispersible polymer powder was obtained as in Example 9-2 except that a flocculate was repeatedly washed with sufficient amounts of purified water upon its collection by filtration.
The redispersible polymer powder and that of Example 9-2 were separately added to portions of a 1% aqueous solution of sodium hydroxide to obtain redispersions. Those redispersions were coated on glass plates and were then dried at room temperature for 3 days, so that films were obtained. Those films were immersed in water for a day. The film formed from the redispersible polymer powder of Example 9-14 was superior in waterproofness.
Example 9-15
After the aqueous emulsion (A-2) and the protective colloid (B-1) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 9-1 were followed so that redispersible polymer powder was obtained.
Example 9-16
After the aqueous emulsion (A-2) and the protective colloid (B-2) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 9-2 were followed so that redispersible polymer powder was obtained.
Example 9-17
After the aqueous emulsion (A-3) and the protective colloid (B-2) were mixed and stirred to give a solid ratio of 50/50, the procedures of Example 9-1 were followed so that redispersible polymer powder was obtained.
Comparative Examples 9-1 to 9-3
The aqueous emulsions (A-1) to (A-3) were each diluted to 10% resin content with purified water and 50 g of a 45% aqueous solution of aluminum sulfate was then added at room temperature to 1,000 g of the thus-diluted emulsion. Each of the aqueous emulsions formed a flocculate. The flocculate was subjected to solid-liquid separation by filtration and was then dried at 80.degree. C. until its residual water content dropped to 2% or lower. The flocculates so dried were however all soft so that their crushing was impossible. Evaluations of redispersibility was therefore conducted without crushing.
Comparative Example 9-4
The mixtures of the aqueous emulsions and the protective colloids, said mixtures having been prepared in Examples 9-1 to 9-8 and 9-15 to 9-17, were separately subjected to spray drying at an inlet air temperature of 120.degree. C. and an outlet air temperature of 60.degree. C. instead of subjecting them to flocculation with any metal salt, whereby redispersible polymer powders were obtained.
All the mixtures formed a great deal of deposit on an inner wall of a drying tower. Each redispersible polymer powder had a yield of 30% or lower and was also substantially inferior in redispersibility.
Comparative Example 9-5
It was attempted to obtain redispersible polymer powder as in Example 9-2 except that the amount of the 45% aqueous solution of aluminum sulfate was changed to 0.01 g. No flocculate was however formed.
Evaluation Example 9-1
Yields were calculated and ranked as in Evaluation Example 1-1.
Evaluation Example 9-2
The redispersible polymer powders were evaluated as in Evaluation Example 1-2.
Evaluation Example 9-3
As in Evaluation Example 1-3, the redispersible polymer powders were mixed in cement and the resulting cement mixes were tested with respect to mixing time, workability, flexural strength and compression strength.
However, the redispersible polymer obtained by spray drying in Comparative Example 9-4 had already been in the form of powder so that powder, which was obtained by classifying the polymer to give a plus-sieve residue of 5% or less on an 80-mesh (200-.mu.m) sieve, was tested in the same manner as described above.
Evaluation Example 9-4
With respect to the polymer powder obtained in Example 9-2, smell and hardening were determined in a similar manner as in Evaluation Example 7-4.
Results
Smell: Not sensed.
Hardening: Setting had been completed.
Evaluation Example 9-5
Evaluation of Redispersibility under the Assumption of Emulsification in Cement
Evaluation of redispersibility was conducted in the same manner as in Evaluation Example 7-5.
The above redispersibility (%) of the polymer powder obtained in Example 9-2 was 40% or higher and was hence good. On the other hand, the redispersibility of the polymer powder obtained by spray drying the polymer of Example 9-2 was 15% or lower and was hence poor.
The compositions of the aqueous emulsions employed in the above Examples and Comparative Examples are shown in Table 9-1, the compositions of the protective colloids employed in the above Examples and Comparative Examples are presented in Table 9-2, and the compositions and evaluation results of the redispersible polymer powders obtained in the above Examples and Comparative Examples are summarized in Table 9-3 to Table 9-14.
Advantages of the Invention
The present invention can provide a (co)polymer or (co)polymer powder having a function to be substantially redispersible in water of pH 5 or higher.
When the (co)polymer or (co)polymer powder is used as a hydraulic cement modifier, the resulting mixed mortar or concrete shows good trowelability and provides a hardened mortar or concrete having excellent flexural strength and compression strength.
The redispersible polymer according to the present invention is characterized in that it requires no
It is hence not required to add fine inorganic powder. The redispersible polymer according to the present invention is therefore also characterized in that it does not cause increases in water absorption properties and flow value, uneven suspension of fine powder and other problems, all of which would be unavoidable if fine inorganic powder were added, and can reduce the water/cement ratio.
As the addition of fine inorganic powder is not required, resulting cement products do not have high water absorption properties.
The redispersible polymer according to the present invention is advantageous over conventional aqueous emulsions at least for the following reasons:
(1) It is possible to reduce the cost and energy required for piping, transportation or storage.
(2) As no large liquid containers are needed, the packaging cost can be reduced.
(3) As no large liquid containers are needed, industrial waste materials can be reduced in volume.
(4) When formed into a premixed one-package product, practically no measuring operation is needed at a construction site, thereby achieving substantial labor saving.
(5) When formed into a premixed one-package product, its mixing with water makes it possible to prepare a desired mortar or concrete in a single step, thereby achieving significant labor saving.
(6) When formed into a premixed one-package product, its components have already been accurately proportioned so that the quality control of a mortar or concrete at the time of construction can be facilitated.
A redispersible polymer produced by the conventional art making use of conventional spray drying is disadvantageous at least for the following reasons:
(1) Particles are prone to thermal cohesion so that the redispersibility is not fully satisfactory.
(2) Conventional spray drying requires large facilities and consumes a great deal of energy, so that it is disadvantageous in cost.
Such problems have been solved by the present invention.
When employed as a cement modifier, the redispersible polymer according to the present invention can impart high tensile strength, flexural strength, compression strength, bonding strength, wear resistance an the like.
Owing to the characteristic feature of the redispersible polymer according to the present invention that it does not absolutely require an anti-binding agent (for example, fine inorganic powder, fine organic powder having no film-forming properties, or the like), it can be used in a wide variety of fields where aqueous emulsions are generally employed, including, for example, construction materials, papermaking chemicals, paints, adhesives, fiber finishes and the like as applications other than cement modifiers.
TABLE 1-1______________________________________Compositions of protective colloidsB-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8______________________________________MAm 100.0 99.5 99.0 97.5 80.0 80.0 30.0 50.0AAm -- -- -- -- -- -- 20.0 --HEMA -- -- -- -- 17.5 -- 25.0 30.0HEA -- -- -- -- -- 17.5 25.0 20.0MAc -- 0.5 1.0 2.5 2.5 2.5 -- --Tg (.degree. C.) 256 256 255 254 162 204 80 82______________________________________
TABLE 1-2______________________________________Compositions of aqueous emulsions (1) C-1 C-2 C-3 C-4 C-5______________________________________Protective colloid B-1 B-2 B-3 B-4 B-5(a1) 100.0 100.0 100.0 100.0 100.0Monomer (a2)ST 40.0 40.0 40.0 40.0 40.0BA 50.0 50.0 50.0 50.0 50.0HEMA 5.0 5.0 5.0 5.0 5.0MAc 3.0 3.0 3.0 3.0 3.0AAm 2.0 2.0 2.0 2.0 2.0n-DM 0.1 0.1 0.1 0.1 0.1Tg of (a2) (.degree. C.) 5 5 5 5 5(a2)/(a1) ratio 50/50 50/50 50/50 50/50 50/50______________________________________
TABLE 1-3______________________________________Compositions of aqueous emulsions (2) C-6 C-7 C-8 C-9______________________________________Protective colloid B-6 B-7 B-8 B-1(a1) 100.0 100.0 100.0 140.0Monomer (a2)ST 40.0 40.0 40.0 40.0BA 50.0 50.0 50.0 50.0HEMA 5.0 5.0 5.0 5.0MAc 3.0 3.0 3.0 3.0AAm 2.0 2.0 2.0 2.0n-DM 0.1 0.1 0.1 0.1Tg of (a2) (.degree. C.) 5 5 5 5(a2)/(a1) ratio 50/50 50/50 50/50 70/30______________________________________
TABLE 1-4______________________________________Compositions of aqueous emulsions (3) C-10 C-11 C-12 C-13 C-14 C-15______________________________________Protective B-1 B-4 B-1 Not Not Notcolloid 100.0 100.0 100.0 used used used(a1)Monomer (a2)MMA 50.0 50.0 -- -- 50.0 --ST -- -- 28.0 40.0 -- 28.0BA 40.0 40.0 -- 50.0 40.0 --BD -- -- 70.0 -- -- 70.0HEMA 5.0 5.0 -- 5.0 5.0 --MAc 3.0 3.0 -- 3.0 3.0 --AA -- -- 2.0 -- -- 2.0AAm 2.0 2.0 -- 2.0 2.0 --n-DM 0.1 0.1 -- 0.1 0.1 --t-DM -- -- 0.3 -- -- 0.3Tg of (a2) -10 -10 -24 5 -10 -24(.degree. C.)(a2)/(a1) ratio 50/50 50/50 50/50 100/0 100/0 100/0______________________________________
TABLE 1-5______________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield B A A A APhysicalpropertiesof resinRedispersibi- A A A A AlityExternal Milky Milky Milky Milky Milkyappearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 1-6______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5Physicalpropertiesof mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A AFlexural strength(kg/cm.sup.2)7 Days 73 70 75 75 7528 Days 132 130 120 125 130Compression strength(kg/cm.sup.2)7 Days 210 210 220 215 19528 Days 350 340 340 335 290______________________________________
TABLE 1-7______________________________________Compositions and evaluation results ofredispersible polyner powders (2)Example 6 7 8 9______________________________________Aqueous emulsion C-6 C-7 C-8 C-9PowderingMethod Floccu- Floccu- Floccu- Floccu- lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield A B B BPhysicalpropertiesof resinRedispersibi- A A A AlityExternal Milky Milky Milky Milkyappearance of white white white whiteredispersionRoom- A A A Atemperaturefilm-formingproperties______________________________________
TABLE 1-8______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd.)Example 6 7 8 9______________________________________Aqueous emulsion C-6 C-7 C-8 C-9Physicalpropertiesof mortarMixing time (sec) 20 20 20 20Trowelability A B B AFlexural strength(kg/cm.sup.2)7 Days 80 75 80 7328 Days 140 140 140 125Compression strength(kg/cm.sup.2)7 Days 200 195 195 20028 Days 290 300 280 290______________________________________
TABLE 1-9______________________________________Compositions and evaluation results ofredispersible polyner powders (3)Example 10 11 12______________________________________Aqueous emulsion C-4 C-4 C-4PowderingMethod Floccu- Floccu- Floccu- lation lation latioAcid HCl CH.sub.3 COOH H.sub.2 SO.sub.4Yield B B BPhysicalpropertiesof resinRedispersibi- A A AlityExternal Milky Milky Milkyappearance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 1-10______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 10 11 12______________________________________Aqueous emulsion C-4 C-4 C-4Physicalpropertiesof mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength(kg/cm.sup.2)7 Days 72 75 8328 Days 130 125 150Compression strength(kg/cm.sup.2)7 Days 205 210 22528 Days 320 335 350______________________________________
TABLE 1-11______________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 13 14 15______________________________________Aqueous emulsion C-10 C-11 C-12PowderingMethod Floccu- Floccu- Floccu- lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield B A BPhysical propertiesof resinRedispersibil- A A AityExternal Milky Milky Milkyappearance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 1-12______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd)Example 13 14 15______________________________________Aqueous emulsion C-10 C-11 C-12Physical propertiesof mortarMixing time (sec) 20 20 20Trowelability A A BFlexural strength(kg/cm.sup.2) 7 Days 70 75 8028 Days 125 130 140Compression strength(kg/cm.sup.2) 7 Days 215 225 20028 Days 310 325 305______________________________________
TABLE 1-13______________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-13 C-14 C-15 C-1 to C-12 (Tested separately)Protective Colloid Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield D D D DPhysical propertiesof resinRedispers- Does Does Does Dibility not not notExternal floccu- floccu- floccu-appearance late late lateof redis- ColorlesspersionRoom- Ctemperaturefilm-formingproperties______________________________________
TABLE 1-14______________________________________Compositions and evaluation results ofredispersible polymer powders (5) (Cont'd)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-13 C-14 C-15 C-1 to C-12 (Tested separately)Protective Colloid Not Not Not Used used used usedPhysical propertiesof mortarMixing time(sec) not not not 20Trowelability evalu- evalu- evalu- CFlexural strength ated ated ated(kg/cm.sup.2) 7 Days due to due to due to 30.about.5028 Days unavail- unavail- unavail- 40.about.60Compression ability ability abilitystrength of any of any of any(kg/cm.sup.2) 7 Days floccu- floccu- floccu- 150.about.19028 Days late late late 190.about.230______________________________________
TABLE 1-15______________________________________Compositions and valuation ResultsRedispersible polymer powders (6)______________________________________Comparative Example______________________________________Aqueous emulsion Physical PropertiesProtective Colloid of resin-free mortarPowderingMethodAcidYieldPhysical propertiesof resinRedispersibilityExternalappearanceof redispersionRoom-temperaturefilm-formingproperties______________________________________
TABLE 1-16______________________________________Compositions and evaluation results ofredispersible polymer powders (6) (Cont'd)Comparative example______________________________________Aqueous emulsion Physical PropertiesProtective Colloid of resin-free mortarPhysical propertiesof mortarMixing time (sec) 20Trowelability CFlexural strength(kg/cm.sup.2) 7 Days 4028 Days 55Compressionstrength(kg/cm.sup.2) 7 Days 17228 Days 210______________________________________
TABLE 2-1______________________________________Compositions of aqueous emulsionobtained in step 1 A-1 A-2 A-3______________________________________MMA -- 50.0 --ST 40.0 -- 28.0BA 50.0 40.0 --BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DM -- -- 0.3Tg of Aqueous 5 -10 -24emulsion (.degree.C.)______________________________________
TABLE 2-2______________________________________Compositions of aqueous emulsionsobtained in step 2 C-1 C-2 C-3 C-4 C-5 C-6______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1 A-1of step 1 100.0 100.0 100.0 100.0 100.0 100.0Monomer(s) of shellsMAm 100.0 99.5 99.0 97.5 80.0 80.0AAm -- -- -- -- --HEMA -- -- -- -- -- 17.5HEA -- -- -- -- 17.5 --MAc -- 0.5 1.0 2.5 2.5 2.5Tg of shells (.degree.C.) 256 256 255 254 162 204Ratio of aqueous 50/50 50/50 50/50 50/50 50/50 50/50emulsion ofstep 1 to shells______________________________________
TABLE 2-3______________________________________Compositions of aqueous emulsionsobtained in step 2 (Cont'd) C-7 C-8 C-9 C-10 C-11 C-12______________________________________Aqueous emulsion A-1 A-1 A-1 A-2 A-2 A-3of step 1 100.0 100.0 140.0 100.0 100.0 100.0Monomer(s) of shellsMAm 30.0 50.0 60.0 100.0 97.5 100.0AAm 20.0 -- -- -- -- --HEMA 25.0 20.0 -- -- -- --HEA 25.0 30.0 -- -- -- --MAc -- -- -- -- 2.5 --Tg of shells (.degree.C.) 80 82 256 256 254 256Ratio of aqueous 50/50 50/50 70/30 50/50 50/50 50/50emulsion ofstep 1 to shells______________________________________
TABLE 2-4______________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5of step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield B A A A APhysical propertiesof resinRedispersib- A A A A AilityExternal Milky Milky Milky Milky Milkyappearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 2-5______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5of step 2Physical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A AFlexural strength(kg/cm.sup.2) 7 days 75 72 76 78 6528 days 130 140 125 120 105Compression strength(kg/cm.sup.2) 7 days 220 215 225 220 20028 days 340 350 345 330 290______________________________________
TABLE 2-6______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 6 7 8 9 10______________________________________Aqueous emulsion C-6 C-7 C-8 C-9 C-10of step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield A B B B BPhysical propertiesof resinRedispersib- A A A A AilityExternal Milky Milky Milky Milky Milkyappearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 2-7______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd)Example 6 7 8 9 10______________________________________Aqueous emulsion C-6 C-7 C-8 C-9 C-10of step 2Physical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A B B A AFlexural strength(kg/cm.sup.2) 7 days 70 70 75 70 7228 days 135 130 135 120 130Compression strength(kg/cm.sup.2) 7 days 195 190 195 210 21028 days 295 290 280 295 310______________________________________
TABLE 2-8______________________________________Compositions and evaluation results ofredispersible polymer powders (3)Example 11 12 13 14 15______________________________________Aqueous emulsion C-11 C-12 C-4 C-4 C-4of step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 HCl CH.sub.3 COOH H.sub.2 SO.sub.4Yield A B B B BPhysical propertiesof resinRedispersib- A A A A AilityExternal Milky Milky Milky Milky Milkyappearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 2-9______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 11 12 13 14 15______________________________________Aqueous emulsion of step 2 C-11 C-12 C-4 C-4 C-4Physical properties of mortarMixing time (sec) 20 20 20 20 20Trowelability A B A A AFlexual 7 days 78 82 70 78 85strength(kg/cm.sup.2) 28 days 135 140 125 130 145Compression 7 days 220 205 210 215 230strength(kg/cm.sup.2) 28 days 330 300 320 340 355______________________________________
TABLE 2-10______________________________________Compositions and evaluation results ofRedispersible polymer powders (5)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 C-1 to C-12 (Tested separately)Shells (S) Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 Not usedYield D D D DPhysical properties of resinRedispersibility Does Does Does DExternal appearance not not not Colorlessof redispersion floccu- floccu- floccu-Room-temperature late late late Cfilm-forming properties______________________________________
TABLE 2-11______________________________________Compositions and evaluation results ofredispersible polymer powders (5) (Cont'd)Comparative Example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 C-1 to C-12 (Tested separately)Shells (S) Not Not Not Used used used usedPhysical properties of mortarMixing time (sec) Not Not Not 20Trowelability evalu- evalu- evalu- CFlexural strength (kg/cm.sup.2) ated ated ated 7 Days due to due to due to 30.about.5028 Days unavail- unavail- unavail- 40.about.60Compression strength ability ability ability(kg/cm.sup.2) of any of any of any 7 Days floccu- floccu floccu 150.about.19028 Days late late late 190.about.230______________________________________
TABLE 2-12______________________________________Compositions and evaluation results ofredispersible polymer powders (6)Comparative example______________________________________Aqueous emulsion Physical propertiesShells (S) of resin-free mortarPowderingMethodAcidYieldPhysical properties of resinRedispersibilityExternal appearanceof redispersionRoom-temperaturefilm-forming properties______________________________________
TABLE 2-13______________________________________Compositions and evaluation results ofredispersible polymer powders (6) (Cont'd)Comparative example______________________________________Aqueous emulsion PhysicalShells (S) properties of resin- free mortarPhysical properties of mortarMixing time (sec) 20Trowelability CFlexural strength (kg/cm.sup.2) 7 days 4028 days 55Compression strength (kg/cm.sup.2) 7 days 17228 days 210______________________________________
TABLE 3-1______________________________________Compositions of Aqueous Emulsions (1) A-1 A-2 A-3______________________________________MMA -- 50.0 --ST 40.0 -- 28.0BA 50.0 40.0 --BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DM -- -- 0.3Tg of Aqueous 5 -10 -24emulsions (.degree. C.)______________________________________
TABLE 3-2______________________________________Compositions of Protective Colloid (a1)______________________________________ B-1 B-2 B-3 B-4______________________________________MAm 100.0 99.5 99.0 97.5AAm -- -- -- --HEMA -- -- -- --HEA -- -- -- --MAc -- 0.5 1.0 2.5Tg (.degree. C.) 256 256 255 254______________________________________ B-5 B-6 B-7 B-8______________________________________MAm 80.0 80.0 30.0 50.0AAm -- -- 20.0 --HEA 17.5 -- 25.0 30.0HEMA -- 17.5 25.0 20.0MAc 2.5 2.5 -- --Tg (.degree. C.) 162 204 80 82______________________________________
TABLE 3-3______________________________________Compositions and Evaluation Results ofRedispersible Polymer Powders (1)Example 1 2 3 4 5______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid (a1) B-1 B-2 B-3 B-4 B-5Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield B A A A APhysical propertiesof resinRedispersibility A A A A AExternal appearance Milky Milky Milky Milky Milkyof redispersion white white white white whiteRoom-temperature A A A A Afilm-forming properties______________________________________
TABLE 3-4______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid (a1) B-1 B-2 B-3 B-4 B-5Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A AFlexural strength (kg/cm.sup.2) 7 Days 80 75 76 78 6728 Days 140 135 130 120 100Compression strength (kg/cm.sup.2) 7 Days 215 205 220 220 20028 Days 350 330 335 325 280______________________________________
TABLE 3-5______________________________________Compositions and Evaluation Results ofRedispersible Polymer Powders (2)Example 6 7 8 9______________________________________Aqueous emulsion A-1 A-1 A-1 A-1Protective colloid (a1) B-6 B-7 B-8 B-1Mixing ratio of emulsion 50/50 50/50 50/50 70/30to protective colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- lation lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield A B B BPhysical properties of resinRedispersibility A A A AExternal appearance Milky Milky Milky Milkyof redispersion white white white whiteRoom-temperature A A A Afilm-forming properties______________________________________
TABLE 3-6______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd.)Example 6 7 8 9______________________________________Aqueous emulsion A-1 A-1 A-1 A-1Protective colloid (a1) B-6 B-7 B-8 B-1Mixing ratio of emulsion 50/50 50/50 50/50 70/30to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20 20Trowelability A B B AFlexural strength (kg/cm.sup.2) 7 Days 70 70 75 7328 Days 110 120 110 125Compression strength (kg/cm.sup.2) 7 Days 190 200 190 20528 Days 280 290 285 300______________________________________
TABLE 3-7______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 10 11 12______________________________________Aqueous emulsion A-1 A-1 A-1Protective colloid (a1) B-4 B-4 B-4Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- lation lation lationAcid HCl CH.sub.3 COOH H.sub.2 SO.sub.4Yield B B BPhysical properties of resinRedispersibility A A AExternal appearance Milky Milky Milkyof redispersion white white whiteRoom-temperature A A Afilm-forming properties______________________________________
TABLE 3-8______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 10 11 12______________________________________Aqueous emulsion A-1 A-1 A-1Protective colloid (a1) B-4 B-4 B-4Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength (kg/cm.sup.2) 7 Days 72 75 8528 Days 130 130 145Compression strength (kg/cm.sup.2) 7 Days 200 200 22528 Days 330 325 355______________________________________
TABLE 3-9______________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 13 14 15______________________________________Aqueous emulsion A-2 A-2 A-3Protective colloid (a1) B-1 B-4 B-1Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4Yield B A BPhysical properties of resinRedispersibility A A AExternal appearance Milky Milky Milkyof redispersion white white whiteRoom-temperature A A Afilm-formingproperties______________________________________
TABLE 3-10______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd.)Example 13 14 15______________________________________Aqueous emulsion A-2 A-2 A-3Protective colloid (a1) B-1 B-4 B-1Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength (kg/cm.sup.2) 7 Days 68 80 7828 Days 125 130 135Compression strength (kg/cm.sup.2) 7 Days 205 225 21528 Days 310 310 310______________________________________
TABLE 3-11______________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 Mixtures employedProtective colloid (a1) Not Not Not in examples 1 to 9 used used used and examples 13 toMixing ratio of emul- 100/100 100/100 100/100 15 (separatelysion to protective tested)colloidPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationAcid H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 H.sub.2 SO.sub.4 Not usedYield D D D DPhysical propertiesof resinRedispersibility Not Not Not DExternal appearance floccu- floccu- floccu- Colorlessof redispersion lated lated latedRoom-temperature Cfilm-formingproperties______________________________________
TABLE 3-12______________________________________Compositions and Evaluation Results ofRedispersible polymer powders (5) (Cont'd)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 MixturesProtective colloid (a1) Not Not Not employed in used used used Examples 1 toMixing ratio of emulsion 100/0 100/0 100/0 9 and Examplesto protective colloid 13 to 15 (separately rested)Physical propertiesof mortarMixing time (sec) Not Not Not 20Trowelability evalu- evalu- evalu- CFlexural strength ated ated ated(kg/cm.sup.2) due to due to due to 7 Days unavail- unavail- unavail- 30.about.5028 Days ability ability ability 40.about.60Compression strength of any of any of any(kg/cm.sup.2) floccu- floccu- floccu- 7 Days late late late 150.about.19028 Days 190.about.230______________________________________
TABLE 3-13______________________________________Compositions and evaluation results ofredispersible polymer powders (6)Comparative example______________________________________Aqueous emulsion Physical propertiesProtective colloid of resin-free(a 1) mortarMixing ratio of emulsionto protective colloidPowderingMethodAcidYieldPhysical propertiesof resinRedisper-sibilityExternalappearanceof redis-persionRoom-temperaturefilm-formingproperties______________________________________
TABLE 3-14______________________________________Compositions and evaluation results ofredispersible polymer powders (6) (Cont'd)Comparative example______________________________________Aqueous emulsion Physical propertiesProtective colloid of resin-free(a1) mortarMixing ratio of emulsionto protective colloidPhysical propertiesof mortarMixing time (sec) 20Trowelability CFlexural strength(kg/cm.sup.2) 7 Days 4028 Days 55Compressionstrength(kg/cm.sup.2) 7 Days 17228 Days 210______________________________________
TABLE 4-1______________________________________Compositions of protective colloids______________________________________ B-1 B-2 B-3 B-4______________________________________MAm 100.0 99.5 99.0 97.5AAm -- -- -- --HEMA -- -- -- --HEA -- -- -- --MAc -- 0.5 1.0 2.5Tg (.degree.C.) 256 256 255 254______________________________________ B-5 B-6 B-7 B-8______________________________________MAm 80.0 80.0 30.0 50.0AAm -- -- 20.0 --HEMA 17.5 -- 25.0 30.0HEA -- 17.5 25.0 20.0MAc 2.5 2.5 -- --Tg (.degree.C.) 162 204 80 82______________________________________
TABLE 4-2______________________________________Compositions of aqueous emulsions (1) C-1 C-2 C-3 C-4 C-5______________________________________Protective colloid B-1 B-2 B-3 B-4 B-5(a1) 100.0 100.0 100.0 100.0 100.0Monomer (a2)ST 40.0 40.0 40.0 40.0 40.0BA 50.0 50.0 50.0 50.0 50.0HEMA 5.0 5.0 5.0 5.0 5.0MAc 3.0 3.0 3.0 3.0 3.0AAm 2.0 2.0 2.0 2.0 2.0n-DM 0.1 0.1 0.1 0.1 0.1Tg of (a2) (.degree.C.) 3 3 3 3 3(a2)/(a1) ratio 50/50 50/50 50/50 50/50 50/50______________________________________
TABLE 4-3______________________________________Compositions of aqueous emulsions (1) (Cont'd) C-6 C-7 C-8 C-9______________________________________Protective colloid B-6 B-7 B-8 B-1(a1) 100.0 100.0 100.0 140.0Monomer (a2)ST 40.0 40.0 40.0 40.0BA 50.0 50.0 50.0 50.0HEMA 5.0 5.0 5.0 5.0MAc 3.0 3.0 3.0 3.0AAm 2.0 2.0 2.0 2.0n-DM 0.1 0.1 0.1 0.1Tg of (a2) (.degree.C.) 3 3 3 3(a2)/(a1) ratio 50/50 50/50 50/50 70/30______________________________________
TABLE 4-4______________________________________Compositions of aqueous emulsions (2) C-10 C-11 C-12 C-13 C-14 C-15______________________________________Protective colloid B-1 B-4 B-1 Not Not Not(a1) 100.0 100.0 100.0 used used usedMonomer (a2)MMA 50.0 50.0 -- -- 50.0 --ST -- -- 28.0 40.0 -- 28.0BA 40.0 40.0 -- 50.0 40.0 --BD -- -- 70.0 -- -- 70.0HEMA 5.0 5.0 -- 5.0 5.0 --MAc 3.0 5.0 -- 3.0 3.0 --AA -- -- 2.0 -- -- 2.0AAm 2.0 2.0 -- 2.0 2.0 --n-DM 0.1 0.1 -- 0.1 0.1 --t-DM -- -- 0.3 -- -- 0.3Tg of (a2) (.degree.C.) -10 -10 -24 3 -10 -24(a2)/(a1) ratio 50/50 50/50 50/50 100/0 100/0 100/0______________________________________
TABLE 4-5______________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5______________________________________Aqueous C-1 C-2 C-3 C-4 C-5emulsionPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltPolyvalent B A A A Ametal saltPhysicalpropertiesor resinRedispers- A A A A AibilityExternal ap- Milky Milky Milky Milky Milkypearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 4-6______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd.)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5Physical propertiesof mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A BFlexural strength(kg/cm.sup.2) 7 Days 72 71 75 75 7528 Days 130 129 120 127 130Compression strength(kg/cm.sup.2) 7 Days 215 210 215 220 19528 Days 350 345 340 340 290______________________________________
TABLE 4-7______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 6 7 8 9 10______________________________________Aqueous C-6 C-7 C-8 C-9 C-4emulsionPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4metal saltYield A B A B APhysicalpropertiesor resinRedispers- A A A A AibilityExternal ap- Milky Milky Milky Milky Milkypearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 4-8______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd.)Example 6 7 8 9 10______________________________________Aqueous emulsion C-6 C-7 C-8 C-9 C-4Physical propertiesof mortarMixing time (sec) 20 20 20 20 20Trowelability B B A A AFlexural strength(kg/cm.sup.2) 7 Days 80 75 80 73 7228 Days 140 140 140 130 130Compression strength(kg/cm.sup.2) 7 Days 200 195 195 195 20528 Days 290 300 280 290 320______________________________________
TABLE 4-9______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 11 12 13 14 15______________________________________Aqueous C-4 C-4 C-4 C-4 C-4emulsionPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2 CaCl.sub.2 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4metal saltYield A C B B BPhysicalpropertiesor resinRedispers- A A A A AibilityExternal ap- Milky Milky Milky Milky Milkypearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 4-10______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 11 12 13 14 15______________________________________Aqueous emulsion C-4 C-4 C-4 C-4 C-4Physical propertiesof mortarMixing time (sec) 20 20 20 20 20Trowelability B B A A AFlexural strength(kg/cm.sup.2) 7 Days 80 75 80 70 7228 Days 140 140 140 130 130Compression strength(kg/cm.sup.2) 7 Days 200 195 195 195 20528 Days 290 300 280 290 320______________________________________
TABLE 4-11______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd.)Example 16 17 18______________________________________Aqueous emulsion C-10 C-11 C-12PowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B A BPhysical propertiesof resinRedispers- A A AibilityExternal Milky Milky Milkyappearance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 4-12______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd.)Example 16 17 18______________________________________Aqueous emulsion C-10 C-11 C-12Physical propertiesof mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength(kg/cm.sup.2) 7 Days 70 75 8528 Days 125 135 145Compression strength(kg/cm.sup.2) 7 Days 210 225 20528 Days 310 330 305______________________________________
TABLE 4-13______________________________________Compositions and evaluation results ofredispersible polymer powders (3)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-13 C-14 C-15 C-1 to C-12 (tested separately)Protective colloid Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedmetal saltYield A A A DPhysical propertiesof resinRedispers- D D D DibilityExternal Color- Color- Color- Color-appearance of less less less lessredispersionRoom- C C C Ctemperaturefilm-formingproperties______________________________________
TABLE 4-14______________________________________Compositions and evaluation resultsredispersible polymer powders (3) (Cont'd.)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-13 C-14 C-15 C-1 to C-12 (tested separately)Protective colloid Not Not Not Used used used usedPhysical propertiesof mortarMixing time (sec) uncru- uncru- uncru- 20Trowelability shable shable shable CFlexural strength(kg/cm.sup.2) 7 Days 30.about.5028 Days 40.about.60Compression strength(kg/cm.sup.2) 7 Days 150.about.19028 Days 190.about.230______________________________________
TABLE 4-15______________________________________Compositions and evaluation resultsredispersible polymer powders (3) (Cont'd.)Comparative example 5______________________________________Aqueous emulsion C-4 PhysicalProtective colloid Used propertiesPowdering of resin-Method Floccu- free mortar lationPolyvalent Al.sub.2 (SO.sub.4).sub.3metal saltYield DPhysical propertiesof resinRedispersibil- Notity floccu-External latedappearance ofRoom-temperaturefilm-formingproperties______________________________________
TABLE 4-16______________________________________Compositions and revaluation resultsredispersible polymer powders (3) (Cont'd.)Comparative example 5______________________________________Aqueous emulsion C-4 PhysicalProtective colloid Used of resin-Physical properties free mortarof mortarMixing time (sec) 20Trowelability CFlexural strength(kg/cm.sup.2) 7 Days 4028 Days 55Compression strength(kg/cm.sup.2) 7 Days 17228 Days 210______________________________________
TABLE 5-1______________________________________Compositions of aqueous emulsionsobtained in step 1 A-1 A-2 A-3______________________________________MMA -- 50.0 --ST 40.0 -- 28.0BA 50.0 40.0 --BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DM -- -- 0.3Tg of Aqueous 3 -10 -24emulsion (.degree.C.)______________________________________
TABLE 5-2______________________________________Compositions of Aqueous EmulsionsObtained in Step 2 C-1 C-2 C-3 C-4 C-5 C-6______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1 A-1of step 1 100.0 100.0 100.0 100.0 100.0 100.0Monomer(s) of shellsMAm 100.0 99.5 99.0 97.5 80.0 80.0AAm -- -- -- -- -- --HEMA -- -- -- -- -- 17.5HEA -- -- -- -- 17.5 --MAc -- 0.5 1.0 2.5 2.5 2.5Tg of shells (.degree.C.) 256 256 255 254 162 204Ratio of aqueous 50/50 50/50 50/50 50/50 50/50 50/50emulsion ofstep 1 to shells______________________________________
TABLE 5-3______________________________________Compositions of aqueous emulsionsobtained in step 2 (Cont'd) C-7 C-8 C-9 C-10 C-11 C-12______________________________________Aqueous emulsion A-1 A-1 A-1 A-2 A-2 A-3of step 1 100.0 100.0 140.0 100.0 100.0 100.0Monomer(s) of shellsMAm 30.0 50.0 60.0 100.0 97.5 100.0AAm 20.0 -- -- -- -- --HEMA 25.0 20.0 -- -- -- --HEA 25.0 30.0 -- -- -- --MAc -- -- -- -- 2.5 --Tg of shells (.degree.C.) 80 82 256 256 254 256Ratio of aqueous 50/50 50/50 70/30 50/50 50/50 50/50emulsion ofstep 1 to shells______________________________________
TABLE 5-4______________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5______________________________________Aqueous C-1 C-2 C-3 C-4 C-5emulsionof step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metalYield B A A A APhysicalpropertiesof resinRedispers- A A A A AibilityExternal ap- Milky Milky Milky Milky Milkyperance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 5-5______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5of step 2Physical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A BFlexural Strength(kg/cm.sup.2) 7 days 73 75 76 72 8028 days 130 140 135 125 135Compression Strength(kg/cm.sup.2) 7 days 210 220 220 220 20028 days 335 350 350 350 290______________________________________
TABLE 5-6______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 6 7 8 9 10______________________________________Aqueous C-6 C-7 C-8 C-9 C-10emulsionof step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield A B A B BPhysicalpropertiesof resinRedispers- A A A A AibilityExternal ap- Milky Milky Milky Milky Milkyperance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 5-7______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 6 7 8 9 10______________________________________Aqueous emulsion C-6 C-7 C-8 C-9 C-10of step 2Physical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability B B A A AFlexural strength(kg/cm.sup.2) 7 days 80 78 82 75 7028 days 145 150 145 125 125Compression strength(kg/cm.sup.2) 7 days 200 210 195 205 20528 days 300 310 280 295 320______________________________________
TABLE 5-8______________________________________Compositions and evaluation results ofredispersible polymer powders (3)Example 11 12 13 14 15______________________________________Aqueous C-11 C-12 C-4 C-4 C-4emulsionof step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4 Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2metal saltYield A B A A CPhysicalpropertiesof resinRedispers- A A A A AibilityExternal Ap- Milky Milky Milky Milky Milkyperance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 5-9______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 11 12 13 14 15______________________________________Aqueous emulsion C-11 C-12 C-4 C-4 C-4of step 2Physical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A AFlexural strength(kg/cm.sup.2) 7 days 75 85 70 72 7328 days 135 145 130 120 130Compression strength(kg/cm.sup.2) 7 days 210 210 200 205 21028 days 335 310 340 350 325______________________________________
TABLE 5-10______________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 16 17 18______________________________________Aqueous emulsion C-4 C-4 C-4PowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent CaCl.sub.2 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B B BPhysicalpropertiesof resinRedispers- A A AibilityExternal Milky Milky Milkyappearance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 5-11______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd)Example 16 17 18______________________________________Aqueous emulsion C-4 C-4 C-4of step 2Physical propertiesof mortarMixing time(sec) 20 20 20Trowelability A A AFlexural Strength(kg/cm.sup.2) 7 days 73 75 8528 days 130 130 145Compression Strength(kg/cm.sup.2) 7 days 200 200 21528 days 350 335 340______________________________________
TABLE 5-12______________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 C-1 to C-12 (tested separately)Shells (S) Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedmetal saltYield A A A DPhysical propertiesof resinRedispersibi- D D D DlityExternal Color- Color- Color- Color-appearance of less less less lessredispersionRoom- C C C Ctemperaturefilm-formingproperties______________________________________
TABLE 5-13______________________________________Compositions and evaluation resultsredispersible polymer powders (5) (Cont'd.)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-13 C-14 C-15 C-1 to C-12 (tested separately)Shells (S) Not Not Not Used used used usedPhysical propertiesof mortarMixing time (sec) Uncru- Uncru- Uncru- 20Trowelability shable shable shable CFlexural strength(kg/cm.sup.2) 7 Days 30.about.5028 Days 40.about.60Compression strength(kg/cm.sup.2) 7 Days 150.about.19028 Days 190.about.230______________________________________
TABLE 5-14______________________________________Compositions and evaluation resultsredispersible polymer powders (6)Comparative exmaple 5______________________________________Aqueous emulsion C-4 PhysicalShells (S) Used propertiesPowdering of resin-Method Floccu- free mortar lationPolyvalent Al.sub.2 (SO.sub.4).sub.3metal saltYield DPhysical propertiesof resinRedispersibi- Notlity floccu-External latedappearance ofRoom-temperaturefilm-formingproperties______________________________________
TABLE 5-15______________________________________Compositions and evaluation resultsredispersible polymer powders (6) (Cont'd.)Comparative example 5______________________________________Aqueous emulsion C-4 PhysicalShells (S) Used propertiesPhysical properties of resin-of mortar free mortarMixing time (sec) 20Trowelability CFlexural strength(kg/cm.sup.2) 7 Days 4028 Days 55Compression strength(kg/cm.sup.2) 7 Days 17228 Days 210______________________________________
TABLE 6-1______________________________________Compositions of aqueous emulsions A-1 A-2 A-3______________________________________MMA -- 50.0 --ST 40.0 -- 28.0BA 50.0 40.0BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DN -- -- 0.3Tg of Aqueous 3 -10 -24emulsions (.degree.C.)______________________________________
TABLE 6-2______________________________________Compositions of protective colloid (a1)______________________________________ B-1 B-2 B-3 B-4______________________________________MAm 100.0 99.5 99.0 97.5AAm -- -- --HEMA -- -- -- --HEA -- -- -- --MAc -- 0.5 1.0 2.5Tg (.degree.C.) 256 256 255 254______________________________________ B-5 B-6 B-7 B-8______________________________________MAm 80.0 80.0 30.0 50.0AAm -- -- 20.0 --HEA 17.5 -- 25.0 30.0HEMA -- 17.5 25.0 20.0MAc 2.5 2.5 -- --Tg (.degree.C.) 162 204 80 82______________________________________
TABLE 6-3______________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5______________________________________Aqueous A-1 A-1 A-1 A-1 A-1emulsionProtective B-1 B-2 B-3 B-4 B-5colloid (a1)Mixing ratio 50/50 50/50 50/50 50/50 50/50of emulsionto protec-tive colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B A A A APhysicalproeprtiesof resinRedisper- A A A A AsibilityExternal Milky Milky Milky Milky Milkyappearance white white white white whiteof redis-persionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 6-4______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid B-1 B-2 B-3 B-4 B-5(a1)Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPhysical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A BFlexural strength(kg/cm.sup.2) 7 Days 80 75 76 78 7528 Days 140 135 130 120 100Compressionstrength(kg/cm.sup.2) 7 Days 215 200 210 220 20028 Days 350 345 350 345 290______________________________________
TABLE 6-5______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 6 7 8 9 10______________________________________Aqueous A-1 A-1 A-1 A-1 A-1emulsionProtective B-6 B-7 B-8 B-1 B-4colloid (a1)Mixing ratio 50/50 50/50 50/50 70/30 50/50of emulsionto protec-tive colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4metal saltYield A B A B APhysicalproeprtiesof resinRedisper- A A A A AsibilityExternal Milky Milky Milky Milky Milkyappearance white white white white whiteof redis-persionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 6-6______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd)Example 6 7 8 9 10______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid B-6 B-7 B-8 B-1 B-4(a1)Mixing ratio of emulsion 50/50 50/50 50/50 70/30 50/50to protective colloidPhysical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability B B A A AFlexural strength(kg/cm.sup.2) 7 Days 73 74 73 73 7228 Days 100 120 110 115 120Compressionstrength(kg/cm.sup.2) 7 Days 195 215 195 205 20028 Days 290 315 290 320 330______________________________________
TABLE 6-7______________________________________Compositions and evaluation results ofredispersible polymer powders (3)Example 11 12 13 14 15______________________________________Aqueous A-1 A-1 A-1 A-1 A-1emulsionProtective B-4 B-4 B-4 B-4 B-4colloid (a1)Mixing ratio 50/50 50/50 50/50 50/50 50/50of emulsionto protec-tive colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2 CaCl.sub.2 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4metal saltYield A C B B BPhysicalproeprtiesof resinRedisper- A A A A AsibilityExternal Milky Milky Milky Milky Milkyappearance white white white white whiteof redis-persionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 6-8______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 11 12 13 14 15______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid B-4 B-4 B-4 B-4 B-4(a1)Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPhysical propertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A AFlexural strength(kg/cm.sup.2) 7 Days 75 72 75 80 7828 Days 125 115 125 130 130Compressionstrength(kg/cm.sup.2) 7 Days 200 210 205 225 21528 Days 350 320 340 330 340______________________________________
TABLE 6-9______________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 16 17 18______________________________________Aqueous A-2 A-2 A-2emulsionProtective B-1 B-4 B-1colloid (a1)Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B A BPhysical propertiesof resinRedisper- A A AsibilityExternal Milky Milky Milkyappearance white white whiteof redis-persionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 6-10______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd.)Example 16 17 18______________________________________Aqueous emulsion A-2 A-2 A-3Protective colloid B-1 B-4 B-1(a1)Mixing ratio of emulsion 50/50 50/50 50/50to protective colloidPhysical propertiesof mortarMixing time(sec) 20 20 20Trowelability A A AFlexural strength(kg/cm.sup.2) 7 Days 70 75 8528 Days 125 130 125Compression strength(kg/cm.sup.2) 7 Days 210 225 20528 Days 330 340 340______________________________________
TABLE 6-11__________________________________________________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative Example 1 2 3 4__________________________________________________________________________Aqueous emulsion A-1 A-2 A-3 Mixtures employed in Examples 1 to 9 and Examples 16 to 18 (separately tested)Protective colloid Not Not Not Used(a1) used used usedMixing ratio of emulsion 100/0 100/0 100/0to protective colloidPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedmetal saltYield A A A DPhysical propertiesof resinRedisper- D D D DsibilityExternal Color- Color- Color- Colorlessappearance less less lessof redis-persionRoom- C C C Ctemperaturefilm-formingproperties__________________________________________________________________________
TABLE 6-12______________________________________Compositions and evaluation results ofredispersible polymer powders (5) (Cont'd)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 MixturesProtective colloid Not Not Not employed in(a1) used used used Examples 1 toMixing ratio of emulsion 100/0 100/0 100/0 9 and Examplesto protective colloid (separatelyPhysical properties rested)of mortarMixing time (sec) uncru- uncru- uncru- 20Trowelability shable shable shable CFlexural strength(kg/cm.sup.2) 7 Days 30.about.5028 Days 40.about.60Compression strength(kg/cm.sup.2) 7 Days 150.about.19028 Days 190.about.230______________________________________
TABLE 6-13______________________________________Compositions and evaluation results ofredispersible polymer powders (6)Comparative exmaple 5______________________________________Aqueous emulsion A-1 Physical propertiesProtective colloid B-4 of resin-free(a1) mortarMixing ratio of emulsion 50/50to protective colloidPowderingMethod Floccu- lationPolyvalent Al.sub.2 (SO.sub.4).sub.3metal saltYield DPhysical propertiesof resinRedisper- Notsibility floccu-External lateappearanceof redis-persionRoom-temperaturefilm-formingproperties______________________________________
TABLE 6-14______________________________________Compositions and evaluation results ofredispersible polymer powders (6) (Cont'd)Comparative example 5______________________________________Aqueous emulsion A-1 Physical propertiesProtective colloid B-4 of resin-free(a1) mortarMixing ratio of emulsion 50/50to protective colloidPhysicalpropertiesof mortarMixing time(sec) 20Trowelability CFlexural strength(kg/cm.sup.2)7 Days 4028 Days 55Compression strength(kg/cm.sup.2)7 Days 17228 Days 210______________________________________
TABLE 7-1______________________________________Compositions of protective colloidsB-1 B-2 B-3 B-4 B-5 B-6 B-7______________________________________HEMA 90.0 80.0 70.0 50.0 30.0 80.0 50.0HEA -- -- -- -- -- -- --MAc 10.0 20.0 30.0 50.0 70.0 -- 45.0AA -- -- -- -- -- 20.0 --AN -- -- -- -- -- -- 5.0Tg (.degree. C.) 66 79 93 123 159 63 118______________________________________
TABLE 7-2______________________________________Compositions of aqueous emulsions (1)______________________________________ C-1 C-2 C-3 C-4 C-5______________________________________Protective colloid B-1 B-2 B-3 B-4 B-5(a1) 100.0 100.0 100.0 100.0 100.0Monomer (a2)ST 50.0 50.0 50.0 50.0 50.0BA 40.0 40.0 40.0 40.0 40.0HEMA 5.0 5.0 5.0 5.0 5.0MAc 3.0 3.0 3.0 3.0 3.0AAm 2.0 2.0 2.0 2.0 2.0n-DM 0.1 0.1 0.1 0.1 0.1Tg of (a2) (.degree. C.) 5 5 5 5 5(a2)/(a1) ratio 50/50 50/50 50/50 50/50 50/50______________________________________ C-6 C-7 C-8______________________________________Protective colloid B-6 B-7 B-2(a1) 100.0 100.0 140.0Mononer (a2)ST 50.0 50.0 50.0BA 40.0 40.0 40.0HEMA 5.0 5.0 5.0MAc 3.0 3.0 3.0AAm 2.0 2.0 2.0n-DM 0.1 0.1 0.1Tg of (a2) (.degree. C.) 5 5 5(a2)/(a1) ratio 50/50 50/50 70/30______________________________________
TABLE 7-3______________________________________Compositions of aqueous emulsions (2) C-9 C-10 C-11 C-12 C-13 C-14______________________________________Protective B-1 B-2 B-2 Not Not Notcolloid 100.0 100.0 100.0 used used used(a1)Monomer (a2)MMA 30.0 30.0 -- -- 30.0 --ST -- -- 28.0 50.0 28.0BA 60.0 60.0 -- 40.0 60.0 --BD -- -- 70.0 -- -- 70.0HEMA 5.0 5.0 -- 5.0 5.0 --MAc 3.0 3.0 -- 3.0 3.0 --AA -- -- 2.0 -- -- 2.0AAm 2.0 2.0 -- 2.0 2.0 --n-DM 0.1 0.1 -- 0.1 0.1 --t-DM -- -- 0.3 -- -- 0.3Tg of (a2) -10 -10 -24 3 -10 -24(.degree. C.)(a2)/(a1) ratio 50/50 50/50 50/50 100/0 100/0 100/0______________________________________
TABLE 7-4______________________________________Compositions and Evaluation Results ofRedispersible polymer powders (1)______________________________________Example 1 2 3 4 5______________________________________Aqueous C-1 C-2 C-3 C-4 C-5emulsionPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B A A A APhysicalpropertiesof resinRedispersibi- A A A A AlityExternal Milky Milky Milky Milky Milkyappearance white white white white whiteofredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________Example 1 2 3 4 5______________________________________Aqueous C-1 C-2 C-3 C-4 C-5emulsionPhysicalpropertiesof mortarMixing 20 20 20 20 20time(sec)Trowelabi- A A A A BlityFlexuralstrength(kg/cm.sup.2)7 Days 72 75 75 71 7528 Days 125 130 125 130 130Compressionstrength(kg/cm.sup.2)7 Days 210 215 220 215 19528 Days 345 350 340 340 290______________________________________Example 6 7 8______________________________________Aqueous C-6 C-7 C-8emulsionPowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield A B BPhysicalpropertiesof resinRedispersibi- A A BlityExternal Milky Milky Milkyappearance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________Example 6 7 8______________________________________Aqueous C-6 C-7 C-8emulsionPhysicalpropertiesof mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength(kg/cm.sup.2)7 Days 75 72 7028 Days 135 130 130Compression strength(kg/cm.sup.2)7 Days 200 205 19028 Days 285 290 280______________________________________
TABLE 7-5______________________________________Compositions and evaluation results ofredispersible polymer powders (2)______________________________________Example 9 10 11 12 13______________________________________Aqueous emulsion C-2 C-2 C-2 C-2 C-2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent FeSO.sub.4 Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2 CaCl.sub.2 Al.sub.2 (SO.sub.4).sub.3metal saltYield A A C B BPhysicalpropertiesof resinRedispersibi- A A A A AlityExternal Milky Milky Milky Milky Milkyappearance of white white white white whiteredispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________Example 9 10 11 12 13______________________________________Aqueous emulsion C-2 C-2 C-2 C-2 C-2Physicalpropertiesof mortarMixing time (sec) 20 20 20 20 20Trowelability B B A A AFlexural strength(kg/cm.sup.2)7 Days 80 80 80 72 7028 Days 140 140 140 140 130Compressionstrength(kg/cm.sup.2)7 Days 205 200 200 195 20528 Days 285 300 280 300 310______________________________________Example 14 15 16 17______________________________________Aqueous emulsion C-2 C-9 C-10 C-11PowderingMethod Floccu- Floccu- Floccu- Floccu- lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B A B APhysicalpropertiesof resinRedispersibi- A A A AlityExternal Milky Milky Milky Milkyappearance of white white white whiteredispersionRoom- A A A Atemperaturefilm-formingproperties______________________________________Example 14 15 16 17______________________________________Aqueous emulsion C-2 C-9 C-10 C-11Physicalpropertiesof mortarMixing time (sec) 20 20 20 20Trowelability A A A AFlexural strength(kg/cm.sup.2)7 Days 75 70 80 7528 Days 125 130 140 135Compression strength(kg/cm.sup.2)7 Days 205 225 200 20028 Days 310 330 305 305______________________________________
TABLE 7-6______________________________________Compositions and evaluation results ofredispersible polymer powders (3)______________________________________Comparative 1 2 3 4example______________________________________Aqueous emulsion C-12 C-13 C-14 C-1 to C-11 (tested separately)Protective colloid Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray lation lation lation dryingPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedmetal saltYield A A A DPhysicalpropertiesof resinRedispersibi- D D D DlityExternal Color- Color- Color- Color-appearance of Iess Iess less lessredispersionRoom- C C C Ctemperaturefilm-formingproperties______________________________________Comparative 1 2 3 4example______________________________________Aqueous emulsion C-12 C-13 C-14 C-1 to C-11 (tested separately)Protective colloid Not Not Not Used used used usedPhysicalpropertiesof mortarMixing time (sec) 20Trowelability uncru- uncru- uncru- C shable shable shableFlexural strength(kg/cm.sup.2)7 Days 30.about.5028 Days 40.about.60Compressionstrength(kg/cm.sup.2)7 Days 150.about.19028 Days 190.about.230______________________________________Comparative example 5______________________________________Aqueous emulsion C-2 Physical properties of resin- free mortarProtective colloid UsedPowderingMethod Floccu- lationPolyvalent Al.sub.2 (SO.sub.4).sub.3metal saltYield DPhysical propertiesof resinRedispersibi- Notlity floccu-External latedappearance ofRoom-temperaturefilm-formingproperties______________________________________Comparative example 5______________________________________Aqueous emulsion C-2 Physical properties of resin- free mortarProtective colloid UsedPhysical propertiesof mortarMixing time (sec) 20Trowelability CFlexural strength(kg/cm.sup.2)7 Days 4028 Days 55Compression strength(kg/cm.sup.2)7 Days 17228 Days 210______________________________________
TABLE 8-1______________________________________Compositions of aqueous emulsionsobtained in step 1 A-1 A-2 A-3______________________________________MMA -- 30.0 --ST 50.0 -- 28.0BA 40.0 60.0 --BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DM -- -- 0.3Tg of Aqueous 5 -10 -24emulsion (.degree. C.)______________________________________
TABLE 8-2______________________________________Compositions of aqueous emulsionsobtained in step 2 C-1 C-2 C-3 C-4 C-5______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1of step 1 100.0 100.0 100.0 100.0 100.0Mononer(s) of shellsMEMA 90.0 80.0 70.0 50.0 30.0HEA -- -- -- -- --MAc 10.0 20.0 30.0 50.0 70.0AA -- -- -- -- --AN -- -- -- -- --Tg of shells (.degree. C.) 66 79 93 123 159Ratio of aqueous 50/50 50/50 50/50 50/50 50/50emulsion ofstep 1 to shells______________________________________
TABLE 8-3______________________________________Compositions of aqueous emulsionsobtained in step 2 (Cont'd) C-6 C-7 C-8 C-9 C-10 C-11______________________________________Aqueous A-1 A-1 A-1 A-2 A-2 A-3emulsion 100.0 100.0 140.0 100.0 100.0 100.0of step 1Monomer(s) ofshellsHEMA 80.0 50.0 54.0 90.0 80.0 90.0HEA -- -- -- -- --MAc -- 45.0 6.0 10.0 20.0 10.0AA 20.0 -- -- -- --AN -- 5.0 -- -- --Tg of shells 63 118 66 66 79 66(.degree. C.)Ratio of 50/50 50/50 70/30 50/50 50/50 50/50aqueousemulsion ofstep 1to shells______________________________________
TABLE 8-4______________________________________Compositions and Evaluation Results ofRedispersible Polymer Powders (1)Example 1 2 3 4 5______________________________________Aqueous C-1 C-2 C-3 C-4 C-5emulsionof step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metalYield B A A A APhysicalpropertiesof resinRedispersib- A A A A AilityExternal Milky Milky Milky Milky MilkyApperance white white white white whiteof re-dispersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 8-5______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion C-1 C-2 C-3 C-4 C-5of step 2Physicalpropertiesof mortarMixing time(sec) 20 20 20 20 20Trowelability A A A A BFlexural Strength(kg/cm.sup.2)7 days 73 76 74 72 7028 days 130 140 135 135 125Compression Strength(kg/cm.sup.2)7 days 210 225 220 220 20028 days 330 350 350 350 290______________________________________
TABLE 8-6______________________________________Compositions and evaluation-results ofredispersible polymer powders (2)Example 6 7 8______________________________________Aqueous emulsion C-6 C-7 C-8of step 2PowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield A A APhysicalpropertiesof resinRedispersib- A A AilityExternal Milky Milky MilkyApperance of white white whiteredispersionRoom- A A Atemperaturefilm-formingproperties______________________________________
TABLE 8-7______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd)Example 6 7 8______________________________________Aqueous emulsion C-6 C-7 C-8of step 2Physicalpropertiesof mortarMixing time (sec) 20 20 20Trowelability A A AFlexural Strength(kg/cm.sup.2)7 days 80 70 7528 days 130 125 125Compression Strength(kg/cm.sup.2)7 days 195 200 20028 days 280 295 320______________________________________
TABLE 8-8______________________________________Compositions and Evaluation Results ofRedispersible Polymer Powders (3)Example 9 10 11 12______________________________________Aqueous emulsion C-9 C-10 C-11 C-2of step 2PowderingMethod Floccu- Floccu- Floccu- Floccu- lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 FeSO.sub.4metal saltYield B A A APhysicalpropertiesof resinRedispersib- A A A AilityExternal Milky Milky Milky MilkyApperance of white white white whiteredispersionRoom- A A A Atemperaturefilm-formingproperties______________________________________
TABLE 8-9______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 9 10 11 12______________________________________Aqueous emulsion C-9 C-10 C-11 C-2of step 2Physicalpropertiesof mortarMixing time (sec) 20 20 20 20Trowelability A A A AFlexural strength(kg/cm.sup.2)7 days 85 70 72 7328 days 145 130 120 130Compression strength(kg/cm.sup.2)7 days 200 200 205 21028 days 310 335 330 325______________________________________
TABLE 8-10______________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 13 14 15 16 17______________________________________Aqueous C-2 C-2 C-2 C-2 C-2emulsionPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2 CaCl.sub.2 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3metal saltYield B C B C APhysicalpropertiesof resinRedisper- A A A A AsibilityExternal Milky Milky Milky Milky Milkyof redis- white white white white whitepersionRoom- A A A A Atemperaturefilm-formingproperties______________________________________
TABLE 8-11______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd)Example 13 14 15 16 17______________________________________Aqueous emulsion C-2 C-2 C-2 C-2 C-2of step 2Physical properties of mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A AFlexural strength (kg/cm.sup.2) 7 days 73 72 80 70 7328 days 130 130 135 130 135Compression strength (kg/cm.sup.2) 7 days 200 200 215 200 21028 days 340 330 335 300 305______________________________________
TABLE 8-12______________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 C-1 to C-11 (tested separately)Shells (S) Not Not Not Used used used usedPowderingMethod Floccu- Floccu- Floccu- Spray drying lation lation lationPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedYield A A A DPhysical propertiesof resinRedispersibility D D D DExternal appearance Color- Color- Color- Color-of redispersion less less less lessRoom-temperature C C C Cfilm-formingproperties______________________________________
TABLE 8-13______________________________________Compositions and evaluation resultsredispersible polymer powders (5) (Cont'd.)Comparative example 1 2 3 4______________________________________Aqueous emulsion C-1 C-2 C-3 C-1 to C-11 (tested separately)Shells (S) Not Not Not Used used used UsedPhysical propertiesof mortarMixing time (sec) uncrush- uncrush- uncrush- 20Trowelability able able able CFlexural strength(kg/cm.sup.2) 7 Days 30.about.5028 Days 40.about.60Compression strength(kg/cm.sup.2) 7 Days 150.about.19028 Days 190.about.230______________________________________
TABLE 8-14______________________________________Compositions and evaluation resultsredispersible polymer powders (6)Example 5______________________________________Aqueous emulsion C-2 PhysicalShells (S) Used propertiesPowdering of resin-Method Floccu- free mortar lationPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3Yield DPhysical properties of resinRedispersibility NotExternal appearance of floccu-Room-temperature latedfilm-forming properties______________________________________
TABLE 8-15______________________________________Compositions and evaluation resultsredispersible polymer powders (6) (Cont'd.)Comparative example 5______________________________________Aqueous emulsion C-2 PhysicalShells (S) Used properties of resin- free mortarPhysical properties of mortarMixing time (sec) 20Trowelability CFlexural strength (kg/cm.sup.2) 7 Days 4028 Days 55Compression strength (kg/cm.sup.2) 7 Days 17228 Days 210______________________________________
TABLE 9-1______________________________________Compositions of aqueous emulsions A-1 A-2 A-3______________________________________MMA -- 50.0 --ST 50.0 -- 28.0BA 40.0 40.0 --BD -- -- 70.0HEMA 5.0 5.0 --MAc 3.0 3.0 --AA -- -- 2.0AAm 2.0 2.0 --n-DM 0.1 0.1 --t-DM -- -- 0.3Tg of Aqueous 5 -10 -24emulsions (.degree. C.)______________________________________
TABLE 9-2______________________________________Compositions of protective colloid (a1)B-1 B-2 B-3 B-4 B-5 B-6 B-7______________________________________HEMA 90.0 80.0 70.0 50.0 30.0 70.0 50.0HEA -- -- -- -- -- -- --MAc 10.0 20.0 30.0 50.0 70.0 20.0 45.0AA -- -- -- -- -- 10.0 --AN -- -- -- -- -- -- 5.0Tg (.degree. C.) 66 79 93 123 159 84 118______________________________________
TABLE 9-3__________________________________________________________________________Compositions and evaluation results ofredispersible polymer powders (1)Example 1 2 3 4 5__________________________________________________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid (a1) B-1 B-2 B-3 B-4 B-5Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3Yield A A A A APhysical properties of resinRedispersibility A A A A AExternal appearance Milky Milky Milky Milky Milkyof redispersion white white white white whiteRoom-temperature A A A A Afilm-forming properties__________________________________________________________________________
TABLE 9-4______________________________________Compositions and evaluation results ofredispersible polymer powders (1) (Cont'd)Example 1 2 3 4 5______________________________________Aqueous emulsion A-1 A-1 A-1 A-1 A-1Protective colloid (a1) B-1 B-2 B-3 B-4 B-5Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A BFlexural strength (kg/cm.sup.2) 7 Days 75 80 76 78 7528 Days 135 140 130 120 100Compression strength (kg/cm.sup.2) 7 Days 205 215 210 220 20028 Days 345 350 350 345 290______________________________________
TABLE 9-5______________________________________Compositions and evaluation results ofredispersible polymer powders (2)Example 6 7 8______________________________________Aqueous emulsion A-1 A-1 A-1Protective colloid (a1) B-6 B-7 B-2Mixing ratio of emulsion 50/50 50/50 70/30to protective colloidPowderingMethod Floccu- Floccu- Floccu- lation lation lationPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3Yield A A APhysical properties of resinRedispersibility A A AExternal appearance Milky Milky Milkyof redispersion white white whiteRoom-temperature A A Afilm-forming properties______________________________________
TABLE 9-6______________________________________Compositions and evaluation results ofredispersible polymer powders (2) (Cont'd.)Example 6 7 8______________________________________Aqueous emulsion A-1 A-1 A-1Protective colloid (a1) B-6 B-7 B-2Mixing ratio of emulsion 50/50 50/50 70/30to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20Trowelability A A AFlexural strength (kg/cm.sup.2) 7 Days 73 73 7228 Days 120 120 115Compression strength (kg/cm.sup.2) 7 Days 195 205 20028 Days 300 320 330______________________________________
TABLE 9-7______________________________________Compositions and evaluation results ofredispersible polymer powders (3)Example 9 10 11 12______________________________________Aqueous emulsion A-1 A-1 A-1 A-1Protective colloid (a1) B-2 B-2 B-2 B-2Mixing ratio of emulsion 50/50 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- lation lation lation lationPolyvalent metal salt FeSO.sub.4 Al.sub.2 (SO.sub.4).sub.3 CaCl.sub.2 CaCl.sub.2Yield A A C BPhysical properties of resinRedispersibility A A A AExternal appearance Milky Milky Milky Milkyof redispersion white white white whiteRoom-temperature A A A Afilm-forming properties______________________________________
TABLE 9-8______________________________________Compositions and evaluation results ofredispersible polymer powders (3) (Cont'd)Example 9 10 11 12______________________________________Aqueous emulsion A-1 A-1 A-1 A-1Protective colloid (a1) B-2 B-2 B-2 B-2Mixing ratio of emulsion 50/50 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20 20Trowelability A A A AFlexural strength (kg/cm.sup.2) 7 Days 75 72 78 7528 Days 120 125 130 130Compression strength (kg/cm.sup.2) 7 Days 210 205 215 21528 Days 330 325 330 335______________________________________
TABLE 9-9__________________________________________________________________________Compositions and evaluation results ofredispersible polymer powders (4)Example 13 14 15 16 17__________________________________________________________________________Aqueous emulsion A-1 A-1 A-2 A-2 A-3Protective colloid (a1) B-2 B-2 B-1 B-2 B-2Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPowderingMethod Floccu- Floccu- Floccu- Floccu- Floccu- lation lation lation lation lationPolyvalent metal Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3Yield B A B A APhysical properties of resinRedispersibility A A A A AExternal appearance Milky milky milky milky milkyof redispersion white white white white whiteRoom-temperature A A A A Afilm-forming properties__________________________________________________________________________
TABLE 9-10______________________________________Compositions and evaluation results ofredispersible polymer powders (4) (Cont'd.)Example 13 14 15 16 17______________________________________Aqueous emulsion A-1 A-1 A-2 A-2 A-3Protective colloid (a1) B-2 B-2 B-1 B-2 B-2Mixing ratio of emulsion 50/50 50/50 50/50 50/50 50/50to protective colloidPhysical properties of mortarMixing time (sec) 20 20 20 20 20Trowelability A A A A AFlexural strength (kg/cm.sup.2) 7 Days 70 75 85 80 8528 Days 125 130 125 130 135Compression strength (kg/cm.sup.2) 7 Days 215 220 205 210 21528 Days 335 335 330 315 320______________________________________
TABLE 9-11__________________________________________________________________________Compositions and evaluation results ofredispersible polymer powders (5)Comparative Example 1 2 3 4__________________________________________________________________________Aqueous emulsion A-1 A-2 A-3 MixturesProtective Colloid (a1) Not Not Not employed in used used used Examples 1 toMixing ratio of emulsion 100/0 100/0 100/0 8 and Examplesto protective colloid 15 to 17 (separately rested)PowderingMethod Flocculation Flocculation Flocculation Spray dryingPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Al.sub.2 (SO.sub.4).sub.3 Not usedYield A A A DPhysical properties of resinRedispersibility D D D DExternal appearance Colorless Colorless Colorless Colorlessof redispersionRoom-temperature C C C Cfilm-forming properties__________________________________________________________________________
TABLE 9-12______________________________________Compositions and evaluation results ofredispersible polymer powders (5) (Cont'd)Comparative example 1 2 3 4______________________________________Aqueous emulsion A-1 A-2 A-3 MixturesProtective colloid (a1) Not Not Not employed in used used used Examples 1 toMixing ratio of emulsion 100/0 100/0 100/0 9 and Examplesto protective colloid 15 to 17 (separately rested)Physical propertiesof mortarMixing time (sec) un- un- un- 20Trowelability crush- crush- crush- CFlexural strength able able able(kg/cm.sup.2) 7 Days 30.about.5028 Days 40.about.60Compression strength(kg/cm.sup.2) 7 Days 150.about.19028 Days 190.about.230______________________________________
TABLE 9-13______________________________________Compositions and evaluation results ofredispersible polymer powders (6)Comparative example 5______________________________________Aqueous emulsion A-1 Physical propertiesProtective colloid (a1) B-2 of resin-freeMixing ratio of emulsion 50/50 mortarto protective colloidPowderingMethod Floccu- lationPolyvalent metal salt Al.sub.2 (SO.sub.4).sub.3Yield DPhysical properties of resinRedispersibility NotExternal appearance floccu-of redispersion lateRoom-temperaturefilm-forming properties______________________________________
TABLE 9-14______________________________________Compositions and evaluation results ofredispersible polymer powders (6) (Cont'd)Comparative example 5______________________________________Aqueous emulsion A-1 Physical propertiesProtective colloid (a1) B-2 of resin-freeMixing ratio of emulsion 50/50 mortarto protective colloidPhysical properties of mortarMixing time (sec) 20Trowelability CFlexural strength (kg/cm.sup.2) 7 Days 4028 Days 55Compression strength (kg/cm.sup.2) 7 Days 17228 Days 210______________________________________

Number	Date	Country
7-180396	Jul 1995	JPX
7-180397	Jul 1995	JPX
7-180398	Jul 1995	JPX
7-325743	Dec 1995	JPX
7-339041	Dec 1995	JPX
7-339042	Dec 1995	JPX
8-027653	Feb 1996	JPX
8-027654	Feb 1996	JPX
8-027655	Feb 1996	JPX
8-035067	Feb 1996	JPX
8-035068	Feb 1996	JPX
8-035069	Feb 1996	JPX

Number	Name	Date
3453345	Mabrey	Jul 1969
4101606	Cenci	Jul 1978
4602059	van Rooden	Jul 1986

Number	Date	Country
0338486	Oct 1989	EPX
0522791	Jan 1993	EPX
0587333	Mar 1994	EPX
11265	May 1969	JPX
59-193903	Nov 1984	JPX
2-173003	Jul 1990	JPX
3-54973	Aug 1991	JPX
3-210336	Sep 1991	JPX
4-185607	Jul 1992	JPX
4-59324	Sep 1992	JPX
5-501575	Mar 1993	JPX
5-194681	Aug 1993	JPX
WO9620963	Jul 1996	WOX

Redispersible polymer and production process thereof

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