Additive building material mixtures containing microparticles whose shells are porous and/or hydrophilic

Abstract

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

Description

Claims

1. Use of polymeric microparticles, containing a void, in hydraulically setting building material mixtures, characterized in that the microparticles have water-permeable shells.

2. Use of polymeric microparticles, containing a void, according to claim 1, characterized in that the shell of the microparticles is porous and/or contains hydrophilic groups.

3. Use of polymeric microparticles, containing a void, according to claim 1, characterized in that the shell of the microparticles comprises monomers containing hydrophilic groups.

4. Use of polymeric microparticles, containing a void, according to claim 3, characterized in that the shell of the microparticles comprises monomers containing acid, hydroxyl, amine, amide and/or cyano groups and/or a mixture of these monomers.

5. Use of polymeric microparticles, containing a void, according to claim 1, characterized in that the shell of the microparticles is porous.

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 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 6, characterized in that the unsaturated carboxylic acid (derivative) monomers are selected from the group of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and crotonic acid.

8. Use of polymeric microparticles, containing a void, according to claim 6, characterized in that the nonionic, ethylenically unsaturated monomers are composed of styrene, butadiene, vinyltoluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide and/or C1-C12 alkyl esters of acrylic or methacrylic 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.

10. 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.

11. Use of polymeric microparticles, containing a void, according to claim 10, characterized in that the microparticles have an average particle size of 200 to 2000 nm.

12. Use of polymeric microparticles, containing a void, according to claim 10, characterized in that the microparticles have an average particle size of 250 to 1000 nm.

13. 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.

14. Use of polymeric microparticles, containing a void, according to claim 13, characterized in that the microparticles are used in an amount of 0.1% to 0.5% by volume, based on the building material mixture.

15. 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.

16. Use of polymeric microparticles, containing a void, according to claim 1, characterized in that the building material mixtures are concrete or mortar.