Process for the preparation of an aqueous composition using polimrica regulators chain water soluble radicalarios

Use of an aqueous polymer composition was prepared by emulsion polymerization initiated by free radicals of a monomer mixture M which comprises i) from 0.01% to 10% by weight of at least one ethylenically unsaturated monomer containing at least M1 an epoxide group and / or at least a hydroxyalkyl group, and ii) from 90% to 99.99% by weight of at least one ethylenically unsaturated monomer M2 which differs from the monomers M1, in an aqueous medium in the presence of a polymer a, polymer a which is composed of a) from 80% to 100% by weight of at least one monocarboxylic acid and / or dicarboxylic ethylenically unsaturated [monomers A1] b) from 0% to 20% by weight of at least one other copolymerizable ethylenically unsaturated monomers other than A1 [monomers A2], in polymerized form, and wherein the proportion of the total amount of the monomer mixture M with respect to the total amount of polymer a is from 1:99 to 99: 1 , having Prepare or polymer A in an aqueous medium by radical-initiated polymerization of the monomers A1 and A2 in the presence of a regulator radical chain containing sulfur, nitrogen and / or phosphorus having at 20 ° C and 1 atm in deionized water solubility > = 5 g / 100 g of water, for the modification of mineral binders.