Patent ID: 9574077
Date: 2017-02-21
CPC Classifications: C08F,C08L,C09J,Y10T

Claim:
1. A process for preparing an aqueous polymer dispersion, the process comprising: performing free-radical aqueous emulsion polymerization of ethylenically unsaturated monomers M by a monomer feed process, wherein the aqueous polymer dispersion has a polymer content of at least 55% by weight, based on the total weight of the dispersion, in which the polymer comprises the ethylenically unsaturated monomer units M and has a glass transition temperature of below −10° C., and in which dispersed polymer particles have a polymodal particle size distribution, wherein 10% to 60% by weight of the polymer particles have a particle diameter in a range from 70 to 180 nm and 40 to 90% by weight of the polymer particles have a particle diameter in a range from 180 to 350 nm, and wherein the particle size distribution has a polydispersity index Q of from 0.5 to 1.5: in which d d d and all particle diameters are determined at 23° C. by centrifuging and discriminating according to mass fractions, and wherein the monomers M, based on a total amount of the monomers M, comprise at least 65% by weight of at least one C