Abstract: A process for the preparation of stable aqueous polymer dispersions which contain an alkenyl-aromatic compound as copolymerized units, by polymerizing monomer mixtures which contain(a) not less than 2% by weight of an alkenyl-aromatic compound and(b) from 0.5 to 10% by weight of an ethylenically unsaturated C.sub.3 -C.sub.5 -carboxylic acid and/or its amide and/or its nitrile and/or an ethylenically unsaturated monomer containing sulfonic acid groups, with or without(c) acrylic acid esters, methacrylic acid esters and/or butadienein aqueous emulsion in the presence of a polymerization initiator, with or without an emulsifier and with or without a polymerization regulator, at a pH below 7, in the presence of from 0.2 to 2% by weight of formaldehyde.

Abstract: A low-odor aqueous binder dispersion containing as copolymerized units, and based on solids content,(a) from 25 to 57.5% by weight of butadiene or of butadiene and an acrylic acid ester, the content of copolymerized butadiene being not less than 15% by weight,(b) from 40 to 70% by weight of styrene,(c) from 1 to 5% by weight of maleic acid or maleic anhydride and(d) from 1.5 to 7% by weight of methacrylamide, for use in paper-coating compositions.