The technical field of the invention relates to plasters, renderings, grouts, waterproofing coatings or mortars notably for the interior or exterior of buildings, such as finishes or mortars for the external thermal insulation as well as joints for the construction.
In particular, the invention concerns water-dispersible powder building material compositions useful for the preparation of wet formulations of plasters or mortars for the construction and the civil engineering industry.
More particularly, the invention refers to cement-free and water-dispersible powder building material compositions comprising a homopolymer or a copolymer as binder.
The invention concerns also the methods of preparation of these dry compositions and wet formulations, the application of these latter onto the surface of buildings or civil engineering works, the so obtained coatings as well as the so coated elements. The applications of these wet formulations can be also joints or other products for the construction as well as mass objects.
Many liquid aqueous acrylic finishes are known. These are wet formulations containing an entirely organic binder made of an acrylic or styrene/acrylic or ethylene/vinylacetate polymer dispersion, a coalescent agent, a water retentive agent such as a cellulosic ether, a dispersant (e.g. a surfactant), a defoamer, a biocide, a carbonate sand and/or a silica sand, a carbonate filler, TiO2, a mineral or organic thickener, a pH regulator, exogenous water and water from the polymer dispersion.
The acrylic or styrene/acrylic polymer dispersion of these acrylic finishes are obtained by emulsion polymerisation.
These known acrylic finishes are ready-to-use pastes which are applied on the exterior surfaces of buildings.
One knows moreover redispersible powders of acrylic or styrene/acrylic polymer. These powders are produced by spray drying of a dispersion of this acrylic or styrene/acrylic polymer, including a water-soluble protective colloid such as polyvinyl alcohol and/or polyacrylates and/or polyvinyl pyrrolidone. See notably EP-723975-A and U.S. Pat. No. 5,252,704. These powders can be used in mortar formulations containing a mineral binder (cement and/or lime).
One of the drawbacks of these cement-free pastes is that they badly withstand the frost and especially the cycles frost/thaw and more generally the thermal shocks. Other drawbacks linked to the aqueous character of these known acrylic finishes, is also that:
These features (i) and (ii) make these known acrylic finishes not really environment friendly.
The present invention pursues at least one of the following objects.
It is an object of the invention to develop redispersible dry compositions of polymer finishes or of other products for the construction which would not have the drawbacks of the known aqueous pasty acrylic finishes or construction products.
It is an object of the invention to develop redispersible dry compositions of polymer finishes which would not be prone to induce efflorescence on the surface of plasters, renderings, coatings made from this composition.
It is an object of the invention to develop redispersible dry compositions of polymer finishes which would not have a highly basic pH after being redispersed into water, to manufacture wet formulations to be applied onto the surface of buildings or civil engineering works.
It is an object of the invention to develop redispersible dry compositions of polymer finishes which would not have an adverse effect on the processing properties (easiness and reproducibility of the mixing-workability-pumpability-non-tackiness-shotcreting- . . . ) or on the mechanical characteristics (water-resistance-hardness-durability-cracking strength- . . . ) of the hardened plasters, renderings, coatings made from these compositions.
It is an object of the invention to develop redispersible dry compositions of polymer finishes which could be mixed with water to manufacture wet formulations to be applied onto the surface of buildings or civil engineering works, to form hardened plasters, renderings or coatings, with protection and waterproofing properties.
It is an object of the invention to develop plasters, renderings, coatings with waterproofing and good-mechanical properties as well as protection, said plasters, renderings, coatings being obtained from dry compositions of polymer finishes easily redispersible in water.
It follows that the invention pertains to a redispersible dry composition of polymer finish or of other products for the construction comprising:
In a remarkable variant, the redispersible dry composition according to the invention, is characterized by a dry % mass ratio specific filler c)*100/polymer a) that is greater or equal to, in an increasing preference order, 10, 20, 30, preferably greater or equal to 50, more preferably greater or equal to 150,
and lower or equal to, in a decreasing preference order, 1200, 1000, 950, preferably lower or equal to 910, more preferably lower or equal to 850.
In an other remarkable variant, the redispersible dry composition according to the invention, is characterized by the water-resistance of a coating obtained from a slurry made by mixing of the dry composition with water to the correct consistency with respect to the whole mix water/dry composition, said water-resistance of the coating being measured according to the test ASTM D2486-06, is greater than, in an increased order of preference, 3000; 4000; 5000; 6000; 10000 cycles.
The thickness of the coating in the above mentioned test could vary from the one of ASTM D2486-06 norm. The thickness could increase if the granulometry of the largest load is greater to the 180 microns requested in the ASTM D2486-06. The thickness of the coating should then correspond to the maximum diameter of the largest load.
The <<correct consistency>> could be for instance determined by comparison with the following products:
In a particular embodiment, the redispersible dry composition of polymer finish according to the invention, comprise:
This composition fulfils at least one of the above mentioned objects.
It is to the credit of the inventors to have designed a redispersible powder dry composition of plaster, mortar, rendering or finish, which is to address to the problem of redispersion in water of polymer-binded coatings or mass objects which are normally only water-resistant when resulting from alkaline aqueous slurries whose pH are greater than 10, especially greater than or equal to 11, and preferably to 12. Now, pH>12 are synonymous of formation of a powdery deposit on the surface of bodies, masonry units, etc., following a loss of water in open air (efflorescence).
In particular, the inventors succeeded in obtaining a dry composition which can be easily and rapidly transformed into a wet formulation, a slurry, the pH of which is below 10, preferably below 9, by mixing with a liquid, e.g. water.
It is then possible to get a coating or a mass object from this slurry. Said coating is advantageously water-resistant and not subject to efflorescence.
Water-resistance is a very interesting property of the coatings or of the mass objects which are the results of pH<10 slurries obtained from mixes of water and dry compositions according to the invention. The water-resistance can be notably given by the wet scrub test and the drip test hereinafter defined.
This result has been obtained notably by incorporating into the dry composition, at least a deprotection agent b) and at least a specific adsorbent filler c).
Such a dry powder composition makes it also possible to overcome the drawbacks of water in the known wet polymer finish formulations, namely strength to thermal shocks, biological instability and cost of transport.
Once redispersed in water, the dry composition forms a wet formulation with good properties of rheology, pumpability, workability, and durability.
And the hardened water-resistant and non-efflorescent coatings or the water-resistant and non-efflorescent joints or other mass objects obtained from this wet formulation have remarkable mechanical properties (hardness-cracking strength), and/or fireproofing and waterproofing properties, and/or decoration properties.
According to the terminology of this text, the following non limitative definitions have to be taken into consideration:
In a preferred embodiment, the powder dry composition according to the invention is cement-free and/or lime-free.
The polymer of the binder a) is preferably chosen from the group comprising, preferably consisting of: acrylic, acrylic/acrylic, styrene/acrylic, styrene/butadiene, vinyl-acetate/ethylene, vinyl-acetate/versatate and vinyl-acetate/versatate/ethylene polymer; the acrylic, acrylic/acrylic, styrene/acrylic polymer being preferred.
In a variant, the binder a) can comprise a combination of different polymers.
The protective colloid of the binder a) is, for instance a polyvinyl alcohol, or a low molecular weight surface active compound, or taken from the group of salts of arylsulfonic acid formaldehyde condensates (U.S. Pat. No. 5,225,478).
Advantageously, the deprotection agent b) is chosen among those which are effective without increasing the pH of the dispersion obtained by mixing said composition with water, to a value less or equal to 10 and preferably to 9.
Regarding the quantitative aspect of the composition according to the invention, it is preferable that the dry % mass ratio deprotection agent b)*100/polymer a) be greater or equal to, in an increasing preference order, 1, 8, 10, 15, 20, 30, preferably comprised between 15 and 25.
Actually, the deprotection agent b) is e.g. chosen in the group of products comprising, preferably consisting of glycol ethers, sodium triphosphate, the glycol ethers being more preferably chosen in the group of products comprising, preferably consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether(2-isopropoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether 2-(2-methoxyethoxy)ethanol, methyl carbitol, diethylene glycol monoethyl ether 2-(2-ethoxyethoxy)ethanol, carbitol cellosolve, diethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, Ethylene glycol methyl ether acetate, ethylene glycol monethylether acetate, ethylene glycol monobutyl ether acetate tripropylene glycol n-butyl ether, dipropylene glycol n-butyl ether, triethylene glycol monobutyl etherpropylene glycol.
The specific adsorbent filler c) is “specific” with respect to its “adsorption capacity” and/or to its oil absorption (OA). In a particularly advantageous embodiment, the specific adsorbent filler c) has an oil absorption (OA) according to ISO 787/5 and in g/100 g: OA greater than or equal to, in an increased order of preference: 1; 5; 10; 20, and for example comprised between 5 and 10.
Said specific adsorbent filler c) is selected preferably among siliceous, calcareous or siliceous-calcareous powders and/or aluminosilicate powders, and more preferably in the calcareous or marble fillers, and, more preferably in the group consisting of the following commercial products:
Concerning the load d), it is advantageously chosen from the group of calcareous and/or siliceous sands, and/or perlite and/or vermiculite.
The water retentive agent e) has the property to keep the water of mixing before the setting. The water is so trapped in the wet formulation paste which improves its bond. To some extent, the water is less absorbed by the support. Salting out on the surface is limited and evaporation is reduced.
The water retentive agent e) is preferably chosen in the group comprising: modified cellulose ethers and/or starches ethers and/or guar ether and their mixes, more preferably consisting of: methylcelluloses, methylhydroxypropylcelluloses, methylhydroxyethylcelluloses and their mixes.
The possible rheological agent f) (also named a “thickener”) is preferably chosen in the group comprising, more preferably consisting of: clays, starch ethers, cellulose ethers and/or gums (e.g. Welan guar xanthane, succinoglycans), modified polysaccharides—preferably among modified starch ethers-, polyvinylic alcohols, polyacrylamides, clays, sepiolites, bentonites, and their mixes, and more preferably chosen in the group of clays, bentonite, montmorillonite.
The possible defoamer g) is preferably chosen in the group comprising, more preferably consisting of: polyether polyols and mixes thereof.
The possible biocide h) is preferably chosen in the group comprising, more preferably consisting of: mineral oxides like zinc oxide and mixes thereof.
The possible pigment i) is preferably chosen in the group comprising, more preferably consisting of: TiO2, iron oxide and mixes thereof.
The possible fibers j) are preferably chosen in the group comprising, more preferably consisting of fibers of polyamid, polyacrylonitrile, polyacrylate, cellulose, polypropylene, glass, sisal, or hemp and their mixes.
The possible mineral binder k) is preferably chosen in the group comprising, more preferably consisting of: portland cement, calcium aluminate cement, calcium sulphate and their mixes.
The possible flame retardant (or flame proof agent), which makes it possible to increase the fire resistance and/or to shrink the speed of flame spreading of the composition is preferably chosen in the group comprising, more preferably consisting of:
The composition according to the invention can also comprise some optional functional ingredients like
As regards the quantitative data, the dry powder redispersible composition according to the invention can be the following, in percent by weight and in an increased preference order:
The present invention also concerns a wet formulation obtained by mixing water with the redispersible dry composition of polymer finish as above defined, said formulation being preferably plasters, renderings, finishes, grouts, waterproofing coatings or mortars. The mixing is done by any appropriate device known in the art. The mixing time is e.g. 1 to 30 min, or even 3 to 10 min.
The water content of such a wet formulation is preferably comprised between, increasing order of preference and in % by weight of the wet formulation, 5-50; 10-40; 15-25.
Another object of the invention is the application of the wet formulation as above defined onto the surface of buildings or civil engineering works to produce coatings.
Another object of the invention is the buildings or civil engineering works or coatings applied thereon or finishes, obtained from the wet formulation as above defined.
The coatings and the mass works or objects obtained from the redispersible powder polymer composition according to the invention have good application properties.
In particular, the coatings according to the invention produce good results in the usual assessment tests, namely: impact resistance, wet scrub resistance 7 day cure, mandrel bend test 7 day cure, tinting strength, QUV test (accelerated weathering) and drip-test measuring the water-resistance in terms of redispersibility, hardness, colour stability, abrasion resistance and texture appearance.
The redispersible powder compositions of the examples are prepared as follows:
Each raw material is weighed according to the proportions of the compositions given below in the point III, then introduced into a classical powder mixer. The mixing time varies between 45 sec. and 10 minutes depending on the composition and on the mixer's efficacy.
III.1 Renders, Plasters
In % by weight
III.2 Grouts
III.3 Waterproofing
III.4 Formula containing mineral binders
IV.1 Preparation of the Samples
The final product is got by mixing of the powder with some water or inversely, till the obtaining of a homogeneous paste. The water contents for the above mentioned formulas according to the examples are:
IV.2 the Tests
a) Drip Test
Flow: 9-12 ml/min
Waterfall height: around 23 cm
Device and settings: Watson-Marlow Limited, 313 Ambient 5 C to 40 C/41 F to 104 F/On time secs=1.5/Off time secs=2.0
b) Wet Scrub Resistance 7 Days Cure
c) Mandrel Bend Test 7 Days Cure
d) Tinting Strength
E) QUV Accelerated Weathering
IV.3 Renders, Plasters Results
IV.4 Grouts Results
IV.5 Waterproofing Results
IV.6 Mineral Binders Results
Number | Date | Country | Kind |
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PCT/EP2010/060337 | Jul 2010 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP11/62001 | 7/13/2011 | WO | 00 | 4/30/2013 |