Patent ID: 6426377
Filing Date: 2002-07-30
Classification: C08J,C08K

Abstract:
A process for improving the stability of an aqueous polymer dispersion to thermal and/or mechanical events, which comprises adding at least one salt of a bis-C4-C18-alkyl ester of a sulfonated dicarboxylic acid having 4 to 8 carbon atoms (=salt S) to the aqueous polymer dispersion after its preparation, wherein the polymer particles of the aqueous polymer dispersion have a ponderal median particle size d50 in the range from 50 to 1000 nm, wherein the polymer comprises ethylenically unsaturated monomers M which comprise at least 50% by weight, based on the overall weight of the monomer M, of one or more monomers M1 which are selected from the group consisting of vinylaromatic monomers, the C1-C12-alkyl esters and the C5-C8-cycloalkyl esters of ethylenically unsaturated mono- and dicarboxylic acids having 3 to 8 carbon atoms, butadiene, and C2-C6-olefins, wherein the salt S is added in an amount of from 0.5 to 5% by weight, based on the weight of the polymer in the aqueous polymer dispersion.