Patent Application
20110287680
This application is based on International Application No. PCT/EP2010/001100, filed Feb. 23, 2010 and published as WIPO Publication No. WO 2010/097192. PCT Application No. PCT/EP2010/001100 was based on German Application No. 10 2009 010 938.2, filed Feb. 27, 2009. The priorities of the foregoing applications are hereby claimed and their disclosures incorporated herein by reference.
The present invention relates to mineral wool fiber battings or mats that are stabilized by a selected binder. These mats can be used as insulating material, for example, to insulate roofs.
Known are aqueous polymer dispersions that are used as a binder for mineral wool fiber battings. Thus, mineral wool battings or mats with cross-linked polymers as binding agents are the subject of various patents.
US-A-2008/0175997 describes binder compositions for glass mats containing an emulsion of polymers functionalized with carboxyl groups and a cross-linking agent with aziridine groups. In comparison with conventional systems, it is a formaldehyde-free dispersion. Its strength and flexibility are comparable to or even better than those of the known systems. This document describes other known binder systems for glass mats that are derived from polymers functionalized with carboxyl groups and have special cross-linking agents such as polyol compounds combined with phosphorus-containing accelerators active hydrogen-containing compounds such as polyols, polyvinyl alcohol or polyacrylate, combined with a fluoroborate accelerator, or cross-linking agents that promote esterification between COOH and OH groups in polymers, or epoxidized oils.
DE-A-10014399 concerns a mixture of two polymeric systems, one of which contains carboxyl and/or hydroxyl groups, while the other contains polymerized functional groups that can result in a reaction with the carboxyl and/or hydroxyl groups of the first system if a covalent binder is formed. Claim 5 mentions a selection of possible polymerized functional groups, including oxazoline. This document makes no reference to the use of a cross-linking agent in a form of water-soluble, non-dispersed reaction components.
DE-A-2604544 describes binders to strengthen the glass fiber mats, in which a carboxyl polymer is made to react with a cross-linking agent chosen from the polyepoxides or masked isocyanates. The base polymer used is limited exclusively to polymers composed of ethylenically unsaturated esters of acrylic or methacrylic acids. The text further suggests that aqueous primary dispersions based on (meth)acrylic produced by aqueous emulsion polymerization are not taken into account as binders in the invention for technical reasons.
JP-A-2000/064167 describes an epoxy resin modified with carboxyl, which is used for cross-linking with components that contain oxazoline groups and can be used to cross-link fibrous materials, especially short-cut fibers.
EP-A-1,018,523 talks about a polymer dispersion that: a) contains dispersed polymers consisting of 5-20 wt % of polymerized carboxylic acid units, b) dissolved polymer consisting of 60-100 wt % of polymerized carboxylic acid units, and c) contains selected alkoxylated long-chain amine as cross-linking agents. This dispersion can be used as a binder for, for example, mineral wool mats.
DE-T-699 21 163 describes an insulating product based on mineral wool on the basis of special mineral fibers with a coating on the basis of thermosetting resin, which is mixed with a latex to improve mechanical strength after aging. Particularly polymers with hydrophilic groups, for example, with carboxyl, hydroxyl or carboxylic acid ester groups are used as latex. Phenol resin is mentioned as the thermosetting resin.
DE-A-197 38 771 describes a binder for mineral wool containing a) a thermoplastic polymer cross-linked with phenol resin, such as polyacrylate or polyvinyl ester, b) phenolic resin, and c) flame retardant.
DE-A-197 20 674 describes a binder for mineral wool containing a) a thermoplastic polymer cross-linked with phenol resin, such as polyacrylate or polyvinyl ester, b) phenolic resin, and c) flame retardant.
EP-A-1 164 163 talks of a binder for mineral wool produced by mixing a carboxylic acid and an alkanolamine in reactive conditions. Used carboxylic acids are, for example, polyacrylic acid, polymethacrylic acid or polymaleic acid.
WO-A-01/05,725 describes a binder for mineral wool that is prepared by reacting a mixture that contains no polymer. However, it contains an amine and a first and second anhydride. Typical representatives of the reaction mix are diethanolamine, aliphatic cyclic anhydride, for example, maleic anhydride, succinic anhydride or hexahydrophthalic anhydride and aromatic anhydride, for example, phthalic acid anhydride.
WO-A-2007/060,236 describes a formaldehyde-free binder for mineral wool comprising a) an aqueous dispersion of a polymeric polycarboxylic acid, b) a selected alkanolamine, for example, ethanolamine, and c) an activated silane, prepared by reacting a silane, for example, alkoxysilane with an enolizable ketone containing at least one carboxyl group or with a ketone with at least one hydroxyl group, for example, dihydroxyacetone or acetylacetone.
JP-A-2006-089,906 describes a formaldehyde-free binder for mineral wool containing a vinyl copolymer with hydroxyl groups and groups derived from an organic acid.
WO-A-2004/085,729 describes a formaldehyde-free binder for mineral wool containing a) a compound with at least 2 cyclic ether groups, and b) a copolymer with nucleophilic groups.
WO-A-2006/136,614 reveals a binder for mineral wool containing a) phenol-formaldehyde binder, and b) hydroxylamine or an amino alcohol.
DE-A-40 24 727 describes a hydrophilic agent for mineral wool that contains a) phenol-formaldehyde binder and as hydrophilic agent a mix of b) water-soluble nitrogen-carbonyl compounds, for example, urea, c) acrylic resin, and d) a mix of carboxyl groups containing fatty acid condensation products with organic phosphoric acid esters.
Binder formulations containing oxazoline compounds as cross-linking agents are also already known.
Thus, U.S. Pat. No. 4,056,502 reveals swellable articles for hygienic application or for disposable towels or door mats. Aqueous carboxyl groups containing polymers are described that are cross-linked with bisoxazoline or bis(amino-oxazoline). The mentioned cross-linking polymer is, for example, acrylate-acrylic acid copolymers.
U.S. Pat. No. 4,297,449 describes the cross-linking of polymers with integrated maleic acid anhydride groups in the polymer backbone using selected oxazoline derivatives as cross-linking agents. The cross-linked products are characterized by high heat and solvent resistance and can be used as adhesives, coating and molding compounds.
U.S. Pat. No. 4,247,671 mentions a compound curable under the effects of moisture. It is characterized by a selected polymer with oxazoline groups and another polymer with, for example, integrated maleic acid anhydride polymer groups in the polymer backbone. The curable compounds can be used to coat a variety of products including glass. Among others, powder coatings containing these compounds are mentioned.
GB-A-1,347,066 describes heat curable compounds comprising a) a polyoxazoline with at least 2 oxazoline rings, and b) a selected polycarboxylic acid with a molecular weight of at least 600. The compounds are used for coating, predominantly powder coatings.
JP-A-2005-126,562 describes adhesive agents based on aqueous phase dispersed thermoplastic resin and a cross-linking agent, for example, an oxazoline compound.
JP-A-2008-088,404 describes an aqueous resin compound with improved substrate adhesion, solvent and water resistance based on a water-soluble or water-dispersible polymer with integrated 2-oxazoline group and a second polymer with the integrated group that reacts with the 2-oxazoline group.
There is increasing demand on the market for products whose formula is free of formaldehyde and whose emission is part of the application process upon receipt of the present property profile.
Thus, the task was to produce cross-linked mineral wool fiber battings or mats that are characterized by the fact that they are cross-linked with formaldehyde-free binder and are highly suitable as insulation materials.
This invention concerns mineral wool fiber mats stabilized by a binder including or consisting of polymers containing carboxyl groups and/or their salt-containing polymers and selected cross-linking agents from the group of compounds with at least divalent metal ions; bisoxazolines; polyoxazolines; bisamino oxazolidines; or polyamino oxazolidines; carbodiimides; bisepoxides; or polyepoxides; and masked isocyanates.
Another aspect of this invention concerns the mineral wool fiber mat containing a bio-soluble fiber material that is cross-linked by a formaldehyde-free binder applied in a pH-area where the fibers are not attacked. This area ideally lies around the neutral point, preferably 4.5-9, particularly 6-7. “Formaldehyde-free” within the scope of this description is a compound that contains less than 10 ppm of formaldehyde.
The invented mineral wool fiber mats or battings contain glass wool and/or mineral wool and could, in principle, contain other additives and/or fibers known in the industry.
The invention is described in detail below with reference to the numerous examples. Such discussion is for purposes of illustration only. Modifications to examples within the spirit and scope of the present invention, set forth in the appended claims will be readily apparent to one of skill in the art. Terminology used herein is given its ordinary meaning as supplemented or explained herein.
All base materials known in the glass industry may be used to produce glass wool. Quartz sand, soda and limestone are usually used. These raw materials can be mixed with waste glass, for example, 70 wt % of waste glass. The melt is spun into fibers in a standard manner.
Mineral wool can be produced in a similar way as glass wool. Basalt, diabase, feldspars, dolomites, sand and limestone are usually used. These raw materials can also be mixed with waste glass. The melt is spun into fibers in a standard manner. Along with the usual raw materials for the production of mineral wools, slags that are the waste products of combustion or manufacturing processes may be used such as blast furnace slags. This form of mineral wool, called slag wool, is also known in the industry.
The used glass or mineral wool is preferably chosen so based on their high bio-solubility. This implies the fiber's ability to dissolve in bodies by the body's own substances and degrade.
A binder is added to the resulting glass or mineral wool fiber mats or battings to ensure their form stability. Then the fiber mat is hardened by heat treatment, for example, in a hot air stream. Additional volatile components are removed from the fiber mat in the process. Formations of nonwoven materials of this type are described, for example, in US 2008/0175997 A1.
In an alternative production method, mineral wool fiber mats could be produced using the wet-laying process. For this, fibers together with the binder could be placed in an aqueous slurry and placed in a fiber mat by a moving reception device such as a water-permeable conveyor belt. After removing the water, the fiber mat is cured by heat treatment such as a hot air stream. Production process for mineral wool mats of this type are described, for example, in DE 601 23 177 T2.
The polymers that are used as polymer basis in the invented mineral wool fiber mats are essentially formed on the basis of one or several ethylenically unsaturated compounds, where at least one of these monomers must have one or several carboxyl groups. Preferably, these are copolymers of vinyl esters and/or esters of α, β ethylenically unsaturated C3-C8 monocarboxylic or dicarboxylic acids and/or alkenyl aromatics polymerized with carboxyl group containing ethylenically unsaturated co-monomers.
Mainly the following groups of monomers come under consideration as basis for the said polymer classes along with monomers that contain carboxyl groups:
One group is the vinyl esters with monocarboxylic acids containing one to eighteen carbon atoms, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl isobutyrate, vinyl valerate, vinyl pivalate, 2-ethylhexanoic acid vinyl, vinyl decanoate, isopropenyl acetate, vinyl ester from saturated branched monocarboxylic acids with 5 to 15 carbon atoms in the acid residue, particularly vinyl ester of Versatic™ acids, vinyl ester of long-chain saturated or unsaturated fatty acids, such as vinyl laurate, vinyl stearate and vinyl ester of benzoic acid and substituted derivatives of benzoic acids like vinyl p-tert-butylbenzoate. However, vinyl acetate is preferred as a main monomer.
Another group of monomers is formed by ester α, β ethylenically unsaturated C3-C8 monocarboxylic or dicarboxylic acids with preferably C1-C18 alkanols and particularly C1-C8 alkanols or C5-C8 cycloalkanols. Dicarboxylic acid esters may be half esters or, preferably, diesters. Suitable C1-C8 alkanols are, for example, methanol, ethanol, n-propanol, i-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, n-hexanol and 2-ethylhexanol. Examples of suitable cycloalkanols are cyclopentanol or cyclohexanol. Examples are esters of acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid or fumaric acid such as methyl(meth)acrylate, ethyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, 1-hexyl(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, di-n-methyl maleate or fumarate, di-n-ethyl maleate or fumarate, di-n-propyl maleate or fumarate, di-n-butyl maleate or fumarate, diisobutyl maleate or fumarate, di-n-pentyl maleate or fumarate, di-n-hexyl maleate or fumarate, dicyclohexyl maleate or fumarate, di-n-heptyl maleate or fumarate, di-n-octyl maleate or fumarate, di(2-ethylhexyl) maleate or fumarate, di-n-nonyl maleate or fumarate, di-n-decyl maleate or fumarate, di-n-undecyl maleate or fumarate, dilauryl maleate or fumarate, dimyristyl maleate or fumarate, dipalmitoyl maleate or fumarate, distearyl maleate or fumarate, and diphenyl maleate or fumarate.
A further group of monomers is formed by the alkenyl-aromatics. These are monoalkenyl aromatics. Examples thereof are styrene, vinyltoluene, vinylxylene, α-methylstyrene or o-chlorostyrene.
A further group of monomers that can be used in addition to the vinyl esters and/or esters of α, β-ethylenically unsaturated C3-C8 monocarboxylic or dicarboxylic acids and/or alkenyl aromatics is formed by aliphatic, monoolefinically or diolefinically unsaturated, optionally halogen-substituted hydro-carbons, such as ethene, propene, 1-butene, 2-butene, isobutene, conjugated C4-C8 dienes, such as 1,3-butadiene, isoprene, chloroprene, vinyl chloride, vinylidene chloride, vinyl fluoride or vinylidene fluoride.
The stated monomers generally form the principal monomers, which, in relation to the total amount of the monomers to be polymerized by the process of free-radical aqueous polymerization, normally account for a fraction of more than 50 wt %, preferably more than 75 wt %.
The monomers are to be selected so as to form a polymer or co-polymer that is stable in usual formaldehyde-free binder formulas, and additionally be characterized by excellent linking properties in the manufacture of mineral wool mats.
Homopolymers or copolymers could be used along with these copolymers that are derived fully or predominantly from ethylenically unsaturated monomers containing the carboxyl group. Some examples are polyacrylic acids or their salts and polymethacrylic acids or their salts, particularly the alkali salts of these polymers.
Along with monomers containing carboxyl groups, preferred binder polymers are derived from the following principal monomers or combinations thereof:
Copolymers based on one or more vinyl esters, especially vinyl acetate; copolymers based on vinyl esters and esters of α, β ethylenically unsaturated C3-C8 mono or dicarboxylic acid with C1-C8 alkanols, particularly ester of (meth)acrylic acids and maleic or fumaric acids; copolymers based on vinyl esters, particularly vinyl acetate with ethylene; copolymers based on vinyl ester, ethylene and α, β ethylenically unsaturated C3-C8 mono or dicarboxylic acid esters with C1-C8 alkanols, particularly (meth)acrylic acid and maleic or fumaric acid esters; or copolymers based on (meth)acrylic acid esters; copolymers based on styrene, butadiene and/or α, β ethylenically unsaturated C3-C8 mono or dicarboxylic acid esters with C1-C8 alkanols, particularly (meth)acrylic acid esters.
Along with the above-mentioned principal monomers, the binder polymers used in the invention contain at least structural units that are derived from monomers containing the carboxyl groups.
This group mainly includes α, β monoethylenically unsaturated mono and dicarboxylic acids with 3 to 10 c-atoms and their water-soluble salts, for example, their sodium salts. The preferred monomers of this group are ethylenically unsaturated C3-C8 carboxylic acids and C4-C8 dicarboxylic acids, for example maleic or fumaric acids, itaconic acid, crotonic acid, vinyl acetic acid, 2-carboxyethyl (meth)acrylate, acrylamidoglycolic acid and particularly acrylic acid, methacrylic acid, and half ester of maleic and fumaric acids such as mono-2-ethylhexyl maleate or monoethyl maleate.
These monomers containing the carboxyl groups are usually polymerized in quantities that depend on the total quantity of monomers to be polymerized, of less than 50 wt %, usually less than 20 wt %, preferably less than 10 wt %.
Naturally, other comonomers that modify the properties in a specific manner could be used for polymerization. Such second monomers are usually polymerized only as modifying monomers in quantities that depend on the total quantity of monomers to be polymerized, of less than 10 wt %.
These monomers could have various functions; for example, they may be used to stabilize polymer dispersions or improve the film cohesion or other properties by cross-linking during polymerization or during film formation and/or react with the cross-linking agents due to suitable functionality.
Monomers that could further stabilize are usually monomers that have an acid function and/or its salts. Along with the monomers containing carboxyl groups listed above this group includes, for example, monomers with other acid functions like ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosfonic acids or dihydrogen phosphates and their water-soluble salts, for example, sodium salts.
Preferred monomers of this group are vinyl sulfonic acids and their alkali salts, acrylamido propanesulfonic acids and their alkali salts, and vinyl phosfonic acids and their alkali salts.
Examples of cross-linked second monomers are monomers with two or more vinyl radicals, monomers with two or more vinylidene radicals, and monomers with two or more alkenyl radicals. Particularly favorable are the diester dihydric alcohols with α,β monoethylenically unsaturated monocarboxylic acids, among which acrylic and methacrylic acids are preferred, diester dihydric carboxylic acids with ethylenically unsaturated alcohols, other hydrocarbons with two ethylenically unsaturated groups or diamides of dihydric amines with α,β monoethylenically unsaturated monocarboxylic acids.
Examples of such two unconjugated ethylenically unsaturated monomers with double bonds are alkylene glycol diacrylate and dimethacrylate such as ethylene glycol diacrylate, 1,2-propylene glycol diacrylate, 1,3-propylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate or methacrylate and ethylene glycol diacrylate or methacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, hexanediol diacrylate, pentaerythritol diacrylate, as well as divinylbenzene, vinyl methacrylate, vinyl acrylate, vinyl crotonate, alkyl methacrylate, alkyl acrylate, dialkyl maleate, dialkyl fumarate, dialkyl phthalate, methylenebisacrylamide, cyclopentadienyl acrylate, divinyl adipate or methylenebisacrylamide.
Monomers with more than two double bonds could also be used, for example, tetraallyloxyethane, trimethylolpropane triacrylate or triallyl cyanurate.
Another group of second monomers is suitable to react either by self cross-linking or with a suitable reaction partner for monomers and/or with available cross-linking agents under selected conditions:
This group includes monomers with N-functional groups, in particular, (meth)acrylamide, allyl carbamate, acrylonitrile, methacrylonitrile, N-methylol(meth)acrylamide, N-methylolallyl carbamate, and also the N-methylol esters, N-alkyl ethers or Mannich bases of N-methylol(meth)acrylamide or N-methylolallyl carbamate, acrylamide glycolic acid, methyl acrylamide methoxyacetate, N-(2,2-dimethoxy-1-hydroxyethyl)acrylamide, N-dimethylaminopropyl(meth)-acrylamide, N-methyl(meth)acrylamide, N-butyl(meth)-acrylamide, N-cyclohexyl(meth)acrylamide, N-dodecyl-(meth) acrylamide, N-benzyl(meth)acrylamide, p-hydroxy-phenyl(meth)acrylamide, N-(3-hydroxy-2,2-dimethyl-propyl)methacrylamide, ethyl imidazolidone (meth)acrylate, N-(meth)acryloyloxyethylimidazolidin-1-one, N-(2-methacrylamido-ethyl)imidazolin-2-one, N-[(3-allyloxy-2-hydroxypropyl)aminoethyl]imidazolin-2-one, N-vinylformamide or N-vinyl-pyrrolidone or N-vinylethylene urea.
One further group of second monomers is formed by hydroxy-functional monomers, such as the C1-C9 hydroxyalkyl esters of acrylic acid or of methacrylic acid, such as n-hydroxyethyl, n-hydroxypropyl or n-hydroxybutyl acrylate and methacrylate, and also their adducts with ethylene oxide or propylene oxide.
One further group of second monomers is formed by those which are self-crosslinking or cross-linkable via carbonyl groups. Examples are diacetoneacrylamide, allyl acetoacetate, vinyl acetoacetate and acetoacetoxyethyl acrylate or methacrylate.
One further group of auxiliary monomers is composed of monomers containing silane groups, examples being vinyltrialkoxysilanes, such as vinyltrimethoxysilane, vinyltriethoxysilane, alkylvinyldialkoxysilanes or (meth)acryloyloxyalkyltrialkoxysilanes, for example, (meth)acryloyloxyethyltrimethoxysilane, or (meth)acryloyloxypropyltrimethoxysilane.
One further group of auxiliary monomers is composed of monomers containing epoxy groups, such as, for example, allyl glycidyl ether, methacryloyl glycidyl ether, butadiene monoepoxides, 1,2-epoxy-5-hexene, 1,2-epoxy-7-octene, 1,2-epoxy-9-decene, 8-hydroxy-6,7-epoxy-1-octene, 8-acetoxy-6,7-epoxy-1-octene, N-(2,3-epoxy)propylacrylamide, N-(2,3-epoxy)propylmethacrylamide, 4-acrylamidophenyl-glycidyl ether, 3-acrylamidophenylglycidyl ether, 4-methacrylamidophenyl-glycidyl ether, 3-methacrylamidophenylglycidyl ether, N-glycidyloxymethylacrylamide, N-glycidyloxypropylmethacrylamide, N-glycidyloxyethylacrylamide, N-glycidyloxyethyl-methacrylamide, N-glycidyloxypropylacrylamide, N-glycidyloxypropylmethacrylamide, N-glycidyloxybutylacrylamide, N-glycidyloxybutylmethacrylamide, 4-acrylamidomethyl-2,5-dimethylphenyl glycidyl ether, 4-methacrylamidomethyl-2,5-dimethylphenyl glycidyl ether, acrylamidopropyldimethyl-(2,3-epoxy)propylammonium chloride, methacrylamidopropyldimethyl-(2,3-epoxy)propylammonium chloride and glycidyl methacrylate.
Within the scope of this invention it is preferred that, if possible, no functional monomers that contain free or bound formaldehyde are used. If this is necessary within the scope of specific product adjustment a compound that acts as formaldehyde scavenger is usually used. Relevant examples are N-nucleophiles or S-nucleophiles like urea or sodium bisulfite as well as other compounds described in the literature.
The binder used for the invention could be produced by any process of radical polymerization. Examples of this are polymerization in mass, in solution, in suspension or, particularly, emulsion polymerization.
Preferred binders contain aqueous polymer dispersions with the above-described copolymers containing carboxyl groups. The application of these dispersions on the mineral wool fiber mats is solvent-free or almost solvent-free.
Along with the polymers that contain carboxyl groups the dispersions preferred in the invention contain protective colloids and/or emulsifiers.
Protective colloids are polymerous compounds that are present during emulsion polymerization and stabilize the dispersion.
Suitable protective colloids are, for example, polyvinyl alcohols, polyalkylene glycols, cellulose derivatives, starch derivatives, and gelatin derivatives, or polymers derived from N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylcarbazole, 1-vinylimidazole, 2-vinylimidazole, 2-vinylpyridine, 4-vinylpyridine, acrylamide, methacrylamide, amino-bearing acrylates, methacrylates, acrylamides and/or methacrylamides. A comprehensive description of further suitable protective colloids is found in Houben-Weyl, Methoden der organischen Chemie, volume XIV/1, Makromolekulare Stoffe [Macromolecular Compounds], Georg-Thieme-Verlag, Stuttgart, 1961, pages 411 to 420.
Emulsifiers are low-molecular and surfactant compounds that are present during the emulsion polymerization and stabilize the dispersion. In the dispersions used for the purposes of this invention, ionic and/or nonionic and/or amphoteric emulsifiers could be used, with particular preference given to nonionic emulsifiers or combinations of nonionic emulsifiers and anionic emulsifiers. A list of suitable emulsifiers is found in Houben-Weyl, Methoden der organischen Chemie, volume XIV/I, Makromolekulare Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961, pages 192-208).
The fraction of protective colloids may be up to 10 wt %, depending on the dispersion, with preference of 1 to 6 wt %.
The fraction of emulsifiers may be up to 10 wt %, depending on the dispersion, with preference of 1 to 6 wt %.
The binders used in the invention contain at least a selected cross-linking agent.
It is typically present in quantities of 0.5 to 10 wt %, depending on the binder, with preference of 0.1 to 5 wt %.
A group of cross-linking agents is chosen from the group of compounds with at least divalent metal ions. These are compounds that can form complex or coordinative bonds with the carboxyl groups of the binder polymers. Typically this group includes salts of
Al3+, Zn2+, Sn2+, Sn4+, Ti4+, TiO2+, Hf4+, HfO2+Zr4+, ZrO2+ and other multivalent or polyvalent ions. Ideally, these ions could also involve other components of the binding agent in the cross-linking process and increase the cross-link density this way. This includes, for example, poly(vinylalcohol) frequently used as a protective colloid.
A further group of cross-linking agents is chosen from the bisoxazoline or polyoxazoline group. Preference is given to formula I compounds or polymers with structural units according to formula II
where R1 alkyls are cycloalkyls, aryls or aralkyls, particularly C2-C6 alkyls or phenyls, R2 hydrogen or alkyl means preferably hydrogen or C1-C6 alkyl, and n means an integer from 1 to 50.
Another group of cross-linking agents is selected from the group of bisoxazolidine or polyamino oxazolidine. Preference is given to compounds of formula III or polymers containing the structural unit of formula IV
where R3 and R4 independently mean hydrogen, alkyl, cycloalkyl or aryl, with preference given to hydrogen or C1-C6 alkyl, R1, R2 and n have the above-defined meanings, and R5 alkyl is cycloalkyl, aryl or aralkyl, preferably C1-C6 alkyl or phenyl.
Another group of cross-linking agents is selected from the group of carbodiimides. Preference is given to compounds of formula V
R6—N═C═N—R7 (V),
where R6 and R7 independently mean hydrogen, alkyl, N,N-dialkyl aminoalkyl, cycloalkyl, aryl or aralkyl, with preference given to C1-C6 alkyl, N,N-dialkyl aminopropyl, phenyl or cyclohexyl.
Other possible cross-linking agents are chosen from the bisepoxide or polyepoxide group. Preference is given to compounds with formula VI or formula VII:
where R8 alkyls are cycloalkyls, aryls or aralkyls, particularly C2-C6 alkyls, phenyls, biphenyls, —C6H4—C(CH3)2—C6H4—, —C6H4—CH2—C6H4—, —C6H4—O—C6H4— or —C6H4—S—C6H4—.
Furthermore, oligomeric or polymeric compounds with a high number of epoxide groups could also be used as cross-linking agents.
Another possible cross-linking agent is selected from the group of masked isocyanates.
This includes, for example, the water-dispersible polyisocyanate preparations EP-A-206,059 or general adducts of alcohols, ethoxylates, lactams, ketoximes, activated methylene compounds, dimethylpyrazoles in diisocyanate, like methylenebis(4-phenyl isocyanate), 1,6-hexane diisocyanate, dicyclohexane diisocyanate, meta-tetramethylxylol diisocyanate or isophorone diisocyanate.
The binders used in the invention could contain other standard additives. This includes, for example, film-forming agents to lower the minimum film-forming temperature (MFT), softening agent, buffers, pH-adjusting agents, dispersing agents, defoamers, fillers, dyes, pigments, silane coupling agents, thickening agents, viscosity control agents, solvents and/or preserving agents.
In addition to the above-mentioned cross-linking agents, the binders used for the invention could contain other cross-linking agents to control cross-linking density and reactivity, which could be present in a low-molecular form or as cross-linking resin.
The binder used in the invention is to be used in a formulation in which a pH value is adjusted in an area optimal for a suitable reactivity of functional groups of polymeric binders with groups of cross-linking agents. This pH range is preferably between 4 and 8, in particular between 6 and 7.5. Suitable pH value may be achieved only after emulsion polymerization to produce the polymer dispersion or adjusted later on by adding pH-adjusting agents in the formula.
In particular, preferred polymer dispersions are produced under regular continuous or discontinuous processes of radical emulsion polymerization.
The execution of radically initiated aqueous emulsion polymerization of ethylenically unsaturated monomers has been described many times before and is well known in the industry [see for example Encyclopedia of Polymer Science and Engineering, Vol. 8, pages 659 to 677, John Wiley & Sons, Inc., 1987; D. C. Blackley, Emulsion Polymerisation, pages 155 to 465, Applied Science Publishers, Ltd., Essex, 1975; D. C. Blackley, Polymer Latices, 2nd Edition, Vol. I, pages 33 to 415, Chapman & Hall, 1997; H. Warson, The Applications of Synthetic Resin Emulsions, pages 49 to 244, Ernest Bonn. Ltd., London, 1972; D. Diederich, Chemie in unserer Zeit 1990, 24, pages 135 to 142, Verlag Chemie, Weinheim; J. Piirma, Emulsion Polymerisation, pages 1 to 287, Academic Press, 1982; F. Hölscher, Dispersionen synthetischer Hochpolymerer, pages 1 to 160. Springer-Verlag, Berlin, 1969 and patent document DE-A 40 03 422. Usually, ethylenically unsaturated monomers are dispersed in aqueous media, frequently using dispersion agents, and polymerized using at least a radical polymerization initiator.
Water-soluble and/or oil-soluble initiator systems like peroxodisulphate, azo compounds, hydrogen peroxide, organic hydroperoxide or dibenzoyl peroxide are used for this purpose. They can be used on their own or in combination with reduced compounds like Fe(II) salts, sodium pyrosulfite, sodium hydrogen sulfite, sodium sulfite, sodium formaldehyde sulfoxylate, ascorbic acid as a redox catalyst system.
The polymeric protective colloids and/or emulsifiers could be added before or during polymerization. Addition of polymeric stabilizers and/or emulsifiers is also possible. Then the appropriate additive is added to this dispersion if necessary for the desired application.
The formulation of the binder used for the invention can be carried out in the standard industry equipment, for example, stirrers or appropriate mixers.
After preparation of the binder, it is usually applied directly to the mineral wool fibers to produce mineral wool fiber mats. This could be carried out using relevant process used in the industry, for example, by spraying, soaking in the dispersion. The reactive binder hardens after its application and the thermal treatment of the moist nonwoven material and solidifies, thus stabilizing the mineral wool fiber mat. The hardening reaction is preferably triggered by increasing temperature. The hardening speed can be affected by suitable choice of formulation. Typical preferred hardening temperatures are 70° C.-250° C., especially 130° C.-180° C.
The invention also concerns the process of producing the above-defined mineral wool fiber mats comprising:
The mineral wool fiber mats of the invention are characterized by very low, preferably no formaldehyde emissions, with comparable mechanical strength and application properties.
The mineral wool fiber mats of the invention can be used primarily as insulation material, in particular for insulation, especially thermal insulation of buildings and construction objects of all types.
The following examples serve to illustrate the invention. Parts and percent specified in the examples refer to weight, unless specified otherwise.
This concerns ®Resyn 1601, a product of Celanese, a polyvinyl acetate dispersion stabilized by polyvinyl alcohol that contains ca. 1 weight of acrylic acid units in the polymer.
The used sample had the following properties:
Viscosity Brookfield RVT (23° C.), spindle 3, 20 rpm: 4500 mPas
pH value: 4.5.
At first, 2.25 parts ®Celvol 840 (partially saponified polyvinyl alcohol by Celanese), 0.1 parts anhydrous sodium acetate and 1.11 parts ®Genapol 0-109 (nonionic emulsifier by Clariant) were dissolved in 81.75 parts deionized water in a glass stirrer with a stirring mechanism, anchor stirrer, feed options and electronic temperature regulator. At room temperature 0.1 parts glacial acetic acid had to be added. The solution was heated to 65° C. After that, a mixture of 3.5 parts monoiso octyl maleate (for dispersions B and C), 2.13 parts dibutyl maleate and 5.75 parts vinyl acetate was added. Five minutes after the adding was finished, the initiator solution consisting of 0.18 parts ammonium persulfate and 1.8 parts water was added. The reaction began and the inside temperature went up to 70° C.
After 15-minute prepolymerization, dosing of a monomer mixture consisting of 10 parts dibutyl maleate and 78.62 parts vinyl acetate (for dispersion B) or 4 parts mono isooctyl maleate, 10 parts dibutyl maleate and 74.62 parts vinyl acetate (for dispersion C) was carried out. The monomer mixture was added over 4 hours. At the same time, a solution consisting of 0.05 parts ammonium persulfate and 0.18 parts sodium acetate (anhydrous) was added to 4.3 parts water. Polymerization took place inside at the reactor temperature between 70° C. and 72° C. and a shell temperature of 66° C. to 68° C. under mild reflow.
Five minutes before the end of monomer dosing, the shell temperature was raised to 72° C. After termination of dosing, a solution of 0.05 parts ammonium persulfate was mixed with 1 part water. The inside temperature of the reactor went up to 90° C., and the shell temperature was raised to 90° C. at the same time.
When the inside temperature reached 88° C., a solution of 0.02 parts ammonium persulfate was dissolved once more in 0.4 parts water. When the inside temperature reached 90° C., the contents were stirred once more for one hour. After the inside temperature lowered to 85° C., 0.09 parts sodium pyrosulfite (Na2S2O5) were dissolved in 1.67 parts water. After cooling down to 70° C., 0.07 parts ®Trigonox AW 70 (70% aqueous solution of tert-butyl hydroperoxide made by Akzo) were added to 1.67 parts water for 1 hour. After cooling down to 40° C., 0.14 parts sodium hydroxide was added to 1.26 parts water to adjust the pH value. After cooling down to room temperature, 0.3 parts ®Agitan 295 (made by Münzing) were added while stirring.
Viscosity Brookfield RVT (23° C.), spindle 3, 20 rpm: 4800 mPas
pH value: 4.2.
Viscosity Brookfield RVT (23° C.), spindle 3, 20 rpm: 13300 mPas pH value: 3.6.
Phenol formaldehyde resins are primarily used in manufacture of mineral wool fibers in accordance with the latest technical standards to form close-knit three dimensional networks during the hardening process. The high cross-link density results in a synthetic material with strong thermosetting characteristics. The combination described in this invention comprising functionalized vinyl ester based polymer dispersions and suitable cross-linking agents such as high molecular polymeric compounds with oxazoline function could result in polymeric systems during the hardening process that are just as strongly linked and with thermosetting properties. Therefore, the cross-link density is used hereafter as a measure for the effectiveness of the binding system.
The cross-link density was determined by finding out the insoluble components in thermally treated thin films from mixtures of dispersion and cross-linking agent. A method similar to that described in US-A-2008/0175997, the disclosure of which is incorporated herein by reference, was used for this purpose. The film thickness of the substrate applied to the flat finish glass plates was 250 μm in all cases. N-dimethylformamide (DMF) was used as the solvent. A Mathis oven (Mathis Labdryer LTE-S) was used to temper the films. The duration of tempering and temperatures are shown in the tables below, which demonstrate examples tested for the purposes of the invention.
The samples were prepared as follows before coating: 2.5 to 7.5% of the respective cross-linking agent was added to the dispersions. The examples listed here made use of the water-soluble polymers oxazoline ®Epocros WS700 made by Nippon Shokubai. The oxazoline was added to the dispersion while stirring slowly for 10 minutes. After that, the pH value of the mixture was determined and the pH value was adjusted to 6 by adding 10% NH4OH solution. The mixture was processed immediately.
In the first study, the dependence of the degree of cross-linking temperature, tempering duration and cross-linking agent concentration was determined for dispersion A. The degree of cross-linking can be affected positively by higher temperature, higher cross-linking agent concentration and longer tempering duration. The quantity of insoluble components from a film of dispersion A without the addition of cross-linking agents served as a comparative example.
In another study, dispersions B and C were compared to dispersion A. The influences of various acid concentrations and monomer components on the cross-linking density and the reactivity of polymer dispersions due to the oxazoline cross-linking agent were obvious. The acid concentration increases from A (1%) to B (3.5%) to 7% for C. In this series, various temperatures and cross-linking agent concentrations were used.
Tables 1 and 2 demonstrate that by using suitable cross-linking agent in the invention examples as compared to comparative examples V1, V2, V3 and V4 (without added cross-linking agent) the share of insoluble components and, therefore, the cross-link density increases depending on the quantity of added cross-linking agent, temperature and tempering duration. In preferred embodiments of the invention a mineral wool fiber batting thus has a cured, crosslinked binder which exhibits % insolubles upon refluxing in a suitable solvent of at least 30% by weight and typically at least 40% by weight or more than 60% by weight. Suitable solvents may include dimethyl formamide, acetone or toluene at a pH of 4.5, for example. Details are provided in United States Patent Application Publication No. 20080175997, the disclosure of which is incorporated herein by reference.
The increased cross-linking density achieved with the help of the invented system and the achieved transition from thermoplastic binder to a material with thermosetting properties is reflected in the increased mechanical stability of the film forming agents. This effect is demonstrated as an experiment in the examples below. The binder system was applied to suitable substrate for hardening. Glass filter paper served as the substrate.
The dispersions were diluted with water to a solid content of 5%. Depending on the experiment additional 5% ®Epocros WS700 (Nippon Shokubai, polymeric oxazoline) or 1.5% ®Bacote 20 (made by Münzing, basic ammonium zirconium carbonate solution) were added to the diluted dispersions. The pH value was adjusted to pH 6 with 10% NaOH or 10% acetic acid.
After that, glass filter paper (Whatman GF/A 20 No: 1820-866) for 60s were soaked in the solution, fixed in a horizontal position in a frame and hung to drip off. Steady binder application of 25% (+/−1%) was achieved as a result. After that the soaked glass filter paper was dried in a convection oven (Mathis Labdryer LTE-S) for 4 minutes in 200° C. and cut up in strips of 5×30 cm (Breitex length).
After storage for 24 hours in 50% relative humidity (RH) and 23° C., the samples were tested for tensile rupture strength on a tension measuring device (Lloyd Negygen, tensile speed 100 mm/min, length of span: 20 cm, maximum force absorption of the force measurement cell 1 kN). The table below demonstrates the force absorption values for tears of the samples. Average values of tensile strengths of four samples are shown. The force absorption of the unbonded substrate is 15 N/20 cm, which was taken into account in the force absorption values shown in the table below.
This table shows that in comparison with comparative examples V5 and V6 with no added cross-linking agent, the force absorption is clearly higher in the tensile strength tests of bonded glass filter. Typically, the relative tensile strength is increased at least 25%, preferably at least 70% as compared to batting stabilized with the same polymer without a crosslinking agent.
While the invention has been described in detail, modifications within the spirit and scope of the invention will be readily apparent to those of skill in the art. In view of the foregoing discussion, relevant knowledge in the art and references discussed above in connection with the Background and Detailed Description, the disclosures of which are all incorporated herein by reference, further description is deemed unnecessary. In addition, it should be understood that aspects of the invention and portions of various embodiments may be combined or interchanged either in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 010 938.2 | Feb 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/001100 | 2/23/2010 | WO | 00 | 8/4/2011 |
