Polyvinyl-Alcohol-Stabilized Redispersible Powders With Plasticized Properties

Abstract

Polyvinyl-alcohol-stabilized redispersible powders which have plasticizing properties are obtained by drying polyvinyl-alcohol-stabilized aqueous dispersions of polymers of one or more monomers from the group of vinyl esters of optionally branched C 1-18 alkylcarboxylic acids, (meth)acrylic esters of optionally branched C 1-15 alcohols, dienes, olefins, vinylaromatics and vinylhalides, in the presence of a copolymer formed from a) one or more monomers from the group of ethylenically unsaturated monocarboxylic acids, ethylenically unsaturated dicarboxylic acids and their anhydrides, each having 4 to 8 carbon atoms, and salts thereof, b) one or more ethylenically unsaturated compounds containing sulfonic, sulfuric, and/or phosphonic acid groups, and salts thereof, and c) one or more monomers from the group consisting of vinyl esters of optionally branched C 1-18 alkylcarboxylic acids and (meth)acrylic esters of optionally branched C 1-15 alcohols.

1 .- 15 . (canceled)  
     
     
         16 . A polyvinyl alcohol-stabilized redispersible powder having plasticizing properties, prepared by drying a polyvinyl alcohol-stabilized, aqueous dispersion of at least one homopolymeric or copolymeric base polymer comprising polymerized monomers selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids, (meth)acrylic esters of optionally branched C 1-15  alcohols, dienes, olefins, vinylaromatics and vinylhalides,  
       in the presence of a plasticizing copolymer comprising a copolymerisate comprising: 
 a) at least one monomer selected from the group consisting of ethylenically unsaturated C 4-8  monocarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acid anhydrides, and salts thereof, in an amount of from about 10 to about 50 weight percent,  
 b) at least one ethylenically unsaturated monomer containing sulfonic, sulfuric, and/or phosphonic acid groups, and/or salts thereof, in an amount of from about 10 to about 50 weight percent, and  
 c) at least one monomer selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids and (meth)acrylic esters of optionally branched C 1-15  alcohols, in an amount of from about 20 to about 80 weight percent  
 said weight percents based on the total weight of said plasticizing copolymer.  
 
     
     
         17 . The redispersible powder of  claim 16 , wherein at least one base polymer is selected from the group consisting of vinyl acetate homopolymers, copolymers of vinyl acetate with ethylene, copolymers of vinyl acetate with ethylene and one or more further vinyl esters, copolymers of vinyl acetate with ethylene and (meth)acrylate(s), copolymers of vinyl acetate with ethylene and vinyl chloride, styrene-acrylate copolymers, and styrene-1,3-butadiene copolymers.  
     
     
         18 . The redispersible powder of  claim 16 , wherein at least one polyvinyl alcohol is selected from the group consisting of partially and fully hydrolyzed polyvinyl alcohols having a degree of hydrolysis of from 80 to 100 mol % and a Höppler viscosity in 4% by weight aqueous solution of from 1 to 30 mPa·s, and partially hydrolyzed, hydrophobically modified polyvinyl alcohols having a degree of hydrolysis of from 80 to 95 mol % and a Höppler viscosity in 4% by weight aqueous solution of from 1 to 30 mPas.  
     
     
         19 . The redispersible powder of  claim 18 , wherein at least one polyvinyl alcohol is selected from the group consisting of partially hydrolyzed polyvinyl alcohols having a degree of hydrolysis of from 80 to 95 mol % and a Höppler viscosity in 4% by weight aqueous solution of from 1 to 30 mPas.  
     
     
         20 . The redispersible powder of  claim 16 , wherein the plasticizing copolymer comprises as comonomer a) at least one monomer selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and salts thereof.  
     
     
         21 . The redispersible powder of  claim 16 , wherein the plasticizing copolymer comprises as comonomer b) at least one monomer selected from the group consisting of vinylsulfonic acid and its alkali metal and alkaline earth metal salts, styrenesulfonic acid and its alkali metal and alkaline earth metal salts, methallylsulfonic acid and its alkali metal and alkaline earth metal salts, p-methallyloxyphenylsulfonic acid and its alkali metal and alkaline earth metal salts, and sulfonic acids of the general formula CH 2 ═CR 1 —CO—X—CR 2 R 3 —R 4 —SO 3 H and their alkali metal and alkaline earth metal salts, where X is O or NH, R 1 , R 2 , and R 3  are identical or different and are H or C 1  to C 3  alkyl, and R 4  is C 1  to C 4  alkylene.  
     
     
         22 . The redispersible powder of  claim 16 , wherein the plasticizing copolymer comprises as comonomer c) at least one monomer selected from the group consisting of vinyl acetate, vinyl propionate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl acrylate.  
     
     
         23 . The redispersible powder of  claim 16 , wherein the fraction of the comonomer units a) is from 10 to 30% by weight, the fraction of the comonomer units b) is from 10 to 30% by weight, and the fraction of the comonomer units c) is from 30 to 70% by weight, the percents by weight based on the total weight of the copolymer, and wherein the copolymer has a number-average molecular weight Mn of less than 50,000 daltons.  
     
     
         24 . The redispersible powder of  claim 16 , wherein the fraction of the plasticizing copolymer in the redispersible powder is from 0.1 to 25% by weight, based on the total weight of the redispersible powder.  
     
     
         25 . A process for preparing the polyvinyl-alcohol-stabilized redispersible powder having plasticizing properties of  claim 16 , comprising drying a polyvinyl-alcohol-stabilized, aqueous dispersion of at least one homopolymeric or copolymeric base polymer comprising at least one polymerized monomer selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids, (meth)acrylic esters of optionally branched C 1-15  alcohols, dienes, olefins, vinylaromatics and vinylhalides,  
       in the presence of a plasticizing copolymer comprising a copolymerizate of 
 a) at least one monomer selected from the group consisting of ethylenically unsaturated C 4-8  monocarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acid anhydrides, and salts thereof,  
 b) at least one ethylenically unsaturated monomer containing sulfonate, sulfate, and/or phosphonate groups,  
 c) at least one monomer selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids, and (meth)acrylic esters of optionally branched C 1-15  alcohols.  
 
     
     
         26 . The process of  claim 25 , wherein drying is effected by means of spray drying following the addition of further polyvinyl alcohol as a spraying aid.  
     
     
         27 . The composition of  claim 16  which is a chemical product for the construction industry, and further comprises at least one hydraulically setting binder selected from the group consisting of cement, gypsum, lime and waterglass.  
     
     
         28 . The composition of  claim 27 , wherein said hydraulically setting binder is a cement selected from the group consisting of Portland, aluminate, pozzolanic, slag, magnesia, and phosphate cements.  
     
     
         29 . The composition of  claim 27  which is a construction adhesive, plaster, render, filling compound, trowel-applied flooring compound, leveling compound, grout, jointing mortar, or paint.  
     
     
         30 . The composition of  claim 27  which is a self-leveling floor-filling compound or flowable screed.  
     
     
         31 . A polyvinyl alcohol-stabilized redispersible powder having plasticizing properties, prepared by drying a polyvinyl alcohol-stabilized, aqueous dispersion of at least one homopolymeric or copolymeric base polymer comprising polymerized monomers selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids, dienes, olefins, vinylaromatics and vinylhalides, in the presence of a plasticizing copolymer comprising a copolymerisate comprising: 
 a) at least one monomer selected from the group consisting of ethylenically unsaturated C 4-8  monocarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acids, ethylenically unsaturated C 4-8  dicarboxylic acid anhydrides, and salts thereof, in an amount of from about 10 to about 50 weight percent,    b) at least one ethylenically unsaturated monomer containing sulfonic, sulfuric, and/or phosphonic acid groups, and/or salts thereof, in an amount of from about 10 to about 50 weight percent, and    c) at least one monomer selected from the group consisting of vinyl esters of optionally branched C 1-18  alkylcarboxylic acids and (meth)acrylic esters of optionally branched C 1-15  alcohols, in an amount of from about 20 to about 80 weight percent    said weight percents based on the total weight of said plasticizing copolymer.    
     
     
         32 . The redispersible powder of  claim 31 , wherein the base polymer further comprises from 1 to 10% by weight of auxiliary monomers.  
     
     
         33 . The redispersible powder of  claim 22 , wherein the auxiliary monomers are selected from the group consisting of ethylenically unsaturated monocarboxylic and dicarboxylic acids, ethylenically unsaturated carboxamides and carbonitriles, monoesters and diesters of fumaric and maleic acid, maleic anhydride; ethylenically unsaturated sulfonic acids and their salts, polyethylenically unsaturated comonomers, glycidyl methacrylate and glycidyl acrylate, silicon-functional comonomers, and monomers containing hydroxyl or CO groups, and mixtures thereof.  
     
     
         34 . The redispersible powder of  claim 32 , wherein the auxiliary monomers are selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, acrylamide, acrylonitrile; fumaric acid, and maleic acid diethyl and diisopropyl esters; maleic anhydride; vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, divinyl adipate, diallyl maleate, allyl methacrylate, triallyl cyanurate; acrylamidoglycolic acid (AGA), methylacrylamidoglycolic acid methyl ester (MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA), N-methylolallylcarbamate, alkyl ethers and esters of N-methylolacrylamide, of N-methylolmethacrylamide, and of N-methylolallylcarbamate, glycidyl methacrylate, glycidyl acrylate, acryloyloxypropyltri(alkoxy)silanes, methacryloyloxypropyltri(alkoxy)silanes, vinyltrialkoxysilanes, vinylmethyldialkoxysilanes, hydroxyalkyl (meth)acrylates, hydroxyethyl, hydroxypropyl or hydroxybutyl (meth)acrylates, diacetoneacrylamide, acetylacetoxyethyl (meth)acrylate, and mixtures thereof.  
     
     
         35 . A chemical construction composition comprising at least one redispersible powder of  claim 31 , and at least one hydraulically settable inorganic binder.  
     
     
         36 . The composition of  claim 35 , further comprising water.