Patent ID: 8790693

Claim:
A process for preparing an aqueous polymer dispersion Pd) which comprises free-radical emulsion polymerizing a plurality of monomers in an aqueous medium at a pH of at least 8, said plurality of monomers consisting of a) N,N-diethylaminoethyl methacrylate, and b) a compound capable of free-radical polymerization selected from esters of α,β-ethylenically unsaturated mono and dicarboxylic acids with C 1 -C 8 alkanols, c) optionally a monomer c) selected from esters of α,β-ethylenically unsaturated mono and dicarboxylic acids with C 9 -C 30 -alkanols and C 2 -C 30 -alkanediols, amides of α,β-ethylenically unsaturated mono and dicarboxylic acids with C 2 -C 30 -amino alcohols which have a primary or secondary amino group, primary amides of α,β-ethylenically unsaturated monocarboxylic acids and their N-alkyl and N,N dialkyl derivatives, N-vinyllactams, open-chain N-vinylamide compounds, esters of vinyl alcohol and allyl alcohol with C 1 C 30 -monocarboxylic acids, vinyl ethers, vinyl aromatic compounds, vinyl halides, vinylidene halides, C 2 -C 8 -monoolefins, unsaturated nitriles, nonaromatic hydrocarbons having at least two conjugated double bonds and mixtures thereof, d) optionally a compound d) which is different from compound a) and has an α,β-ethylenically unsaturated double bond capable of free radical polymerization and at least one cationic group per molecule as copolymerized units.