Patent ID: 8252296

Claim:
An aqueous polymer dispersion Pd) obtained by free-radical polymerization of a monomer mixture M) comprising a) at least one α,β-ethylenically unsaturated amide-group-containing compound of the formula I where R 2 is a group of the formula CH 2 ═CH— and R 1 and R 3 , independently of one another, are H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or R 1 and R 3 , together with the amide group to which they are bonded, are a lactam with 5 to 8 ring atoms, b) at least one free-radically polymerizable crosslinking compound with at least two α,β-ethylenically unsaturated double bonds per molecule, c) at least one compound with a free-radically polymerizable α,β-ethylenically unsaturated double bond and at least one cationogenic and/or cationic group per molecule, wherein the monomer mixture M) is polymerized in an aqueous medium in the presence of 10 to 90% by weight of at least one polymeric anionic dispersant D) based on the total weight of component a) and the at least one polymeric anionic dispersant D), and wherein the at least one polymeric anionic dispersant D) is selected from the group consisting of maleic acid-acrylic acid copolymers and salts thereof, maleic acid-methyl vinyl ether copolymers and salts thereof, maleic acid-olefin copolymers and salts thereof, and maleic anhydride-styrene copolymers.