Patent ID: 8039521

Claim:
A method of preparing a hydraulically setting building material mixture, comprising: adding a mixture of polymeric microparticles having a diameter of between 100 nm and 150 μm to a hydraulically setting building material; wherein at least one of the microparticles present in the mixture has a diameter of less than 1000 nm; wherein at least one of the microparticles is a water-filled polymer particle having a diameter of more than 10 μm; and wherein said polymeric microparticles comprise a void; wherein at least one of the microparticles comprises a polymer core (A), which is swollen using an aqueous base and which comprises one or more ethylenically unsaturated monomer having a carboxylic acid group and being in polymerized form, and a polymer envelope (B), which comprises predominantly nonionic, ethylenically unsaturated monomers in polymerized form.