Additive building material mixtures containing ionically swollen microparticles

Abstract

The present invention relates to the use of polymeric microparticles in hydraulically setting building material mixtures for the purpose of enhancing their frost resistance and cyclical freeze/thaw durability.

1 . 1 . Use of polymeric microparticles, containing a void, in hydraulically setting building material mixtures, characterized in that the core of these particles is swollen by means of ionic bases. 
   
   
       2 . 2 . Use of polymeric microparticles, containing a void, in hydraulically setting building material mixtures, according to claim  1 , characterized in that the base used for swelling is selected from the group of sodium hydroxide, potassium hydroxide, barium hydroxide or a mixture thereof. 
   
   
       3 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the outer shell may contain acid-containing monomers and/or hydrophilic, nonionic monomers. 
   
   
       4 . Use of polymeric microparticles, containing a void, according to  claim 3 , characterized in that the outer shell contains 0 to 15% by weight, based on the total monomer mixture of the shell, of one or more monomers containing acid groups and/or 0 to 25% by weight, based on the total monomer mixture of the shell, of one or more hydroxyl-, amino-, amido- and/or cyano-containing monomers. 
   
   
       5 . Use of polymeric microparticles, containing a void, according to  claim 3 , characterized in that the outer shell contains 0.2% to 8% by weight of one or more acid-containing monomers and/or 0.5% to 15% by weight of hydrophilic, nonionic monomers. 
   
   
       6 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the microparticles are composed of polymer particles which comprise a polymer core (A), which is swollen by means of an ionic aqueous base and contains one or more unsaturated carboxylic acid (derivative) monomers, and a polymer envelope (B), which is composed predominantly of nonionic, ethylenically unsaturated monomers. 
   
   
       7 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the outer shell contains nonionic, ethylenically unsaturated monomers selected from styrene, butadiene, vinyltoluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide and/or C1-C12 alkyl esters of acrylic or methacrylic acid. 
   
   
       8 . Use of polymeric microparticles, containing a void, according to  claim 5 , characterized in that the unsaturated carboxylic acid (derivative) monomers of the core A are selected from the group of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and crotonic acid. 
   
   
       9 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the microparticles have a polymer content of 2% to 98% by weight. 
   
   
       8 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the microparticles have an average particle size of 100 to 5000 nm. 
   
   
       9 . Use of polymeric microparticles, containing a void, according to  claim 8 , characterized in that the microparticles have an average particle size of 200 to 2000 nm. 
   
   
       10 . Use of polymeric microparticles, containing a void, according to  claim 9 , characterized in that the microparticles have an average particle size of 250 to 1000 nm. 
   
   
       11 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the microparticles are used in an amount of 0.01% to 5% by volume, based on the building material mixture. 
   
   
       12 . Use of polymeric microparticles, containing a void, according to  claim 11 , characterized in that the microparticles are used in an amount of 0.1% to 0.5% by volume, based on the building material mixture. 
   
   
       13 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the building material mixtures are composed of a binder selected from the group of cement, lime, gypsum and anhydrite. 
   
   
       14 . Use of polymeric microparticles, containing a void, according to claim  1 , characterized in that the building material mixtures are concrete or mortar.