Abstract: An aqueous polymer composition is described comprising a homogeneous acrylic polymer dispersion produced by emulsion polymerization of a monomer mixture comprising: (A) from 85 to 99.9 wt % of one or more main monomers selected from C1-C12-alkyl esters of acrylic acid or C5-C12-alkyl esters of methacrylic acid, styrene, and vinyl toluene in such a ratio as to produce a polymer having a Tg in the range of ?20 to +65° C.; and (B) from 0.1 to 5 wt % of at least one stabilizing monomer selected from ethylenically unsaturated monocarboxylic acids or amides thereof, ethylenically unsaturated dicarboxylic acids or anhydrides or amides thereof, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphoric acids, and ethylenically unsaturated phosphonic acids. The emulsion polymerization is conducted in the presence of 0.05 to 3 wt %, based on the total weight of monomers in the monomer mixture, of a chain transfer agent (C).

Abstract: A polymer dispersion comprises particles of a polymer composition formed at least partially by emulsion polymerization of first and second, simultaneously added, substantially styrene-free monomer feeds in the presence of an initiator in a reaction zone. The first monomer feed comprises monomers selected to produce a copolymer having a glass transition temperature less than or equal to about ?10° C., while the second monomer feed comprises monomers selected to produce a copolymer having a glass transition temperature greater than or equal to about 50° C. The relative rate of addition of the first and second monomer feeds into the reaction zone is continuously changed during at least part of the emulsion polymerization and the rate of addition of the initiator is changed step-wise at least once during the addition of the first and second monomer feeds.