Patent ID: 8193271

Claim:
A process for preparing an aqueous polymer composition by the free radically initiated emulsion polymerization of a monomer mixture M comprising i) from 0.01 to 10% by weight of at least one ethylenically unsaturated monomer M1 which comprises at least one epoxide group and/or at least one hydroxyalkyl group, and ii) from 90 to 99.99% by weight of at least one additional ethylenically unsaturated monomer M2 which differs from the monomers M1, in an aqueous medium in the presence of a polymer A comprising a) from 80 to 100% by weight of at least one ethylenically unsaturated mono- and/or dicarboxylic acid monomer A1 and b) from 0 to 20% by weight of at least one additional ethylenically unsaturated monomer A2 which differs from the monomers A1, incorporated in the form of polymerized units, and the ratio of the total amount of the monomer mixture M to the total amount of the polymer A being from 1:99 to 99:1, wherein the polymer A has been prepared in an aqueous medium by the free radically initiated polymerization of the monomers A1 and A2 in the presence of a sulfur-, nitrogen-, and/or phosphorus-containing free radical chain regulator which at 20° C. and 1 atm in demineralized water has a solubility of ≧5 g/100 g of water.