Patent ID: 7772318
Filing Date: 2010-08-10
Classification: C08F,C08L,C09D

Abstract:
1. An aqueous polymer dispersion comprising polymer particles (A), polymer particles (B) and at least one low molecular weight polymer (C) where, a) polymer particles (A) comprise high molecular weight polymer pA having Mw >50,000 and acid number of from 0 to 160, b) polymer particles (B) comprise high molecular weight polymer pB having Mw >50,000 and acid number of from 0 to 160, c) (C) is an addition polymer having a calculated Tg,(low) of less than 10° C., Mn <10,000, acid number of from 0 to 80, formed by the polymerization of at least one ethylenically unsaturated nonionic monomer, wherein d) the weight percentage of pA, based on the total weight of polymer in said dispersion, is at least 5%, e) the weight percentage of (C) is at least 5%, based on the total weight of pA, f) pA is formed in the presence of (C) or (C) is formed in the presence of pA, g) polymer particles (A) differ from polymer particles (B) in at least one of, particle size, Tg, acid number, composition, molecular weight, molecular weight distribution, polymer chain structure, h) the at least one ethylenically unsaturated nonionic monomer is a (meth)acrylic ester, styrene, a substituted styrene, butadiene, a vinyl ester, a vinyl monomer, vinylidene chloride, or a combination comprising at least one of the foregoing monomers, and i) high molecular weight polymers pA and pB each have a ratio of Mw/Mn of 1.75 to 6.5.