Patent ID: 7795343

Claim:
A polymer composition comprising polymer particles dispersed in an aqueous medium, wherein the polymer particles comprise, based on the weight of the polymer particles: (a) from 20 to 70 weight. % of a first polymer wherein the first polymer has a Tg from −30° C. to 100° C. and comprises as polymerized units, based on the weight of the first polymer i) 15 to 50 weight % of one or more of the following monomers: acrylonitrile, methacrylonitrile, vinylbenzonitrile and its isomers, cyanoacrylates, alpha-cyano styrene and cyanated styrenics, and ii) 50 to 85 weight % of one or more ethylenically unsaturated comonomers, and (b) 30 to 80 weight % of a second polymer wherein the second polymer has a Tg from −10° C. to 18° C. and comprises as polymerized units, based on the weight of the second polymer: i) 70 to 98.5 weight % of one or more ethylenically unsaturated comonomers, ii) 0.5 to 10 weight % of one or more acid functional or anionic monomers, and iii) 1 to 20 weight % of one or more monomers selected from the group consisting of acetoacetoxyethyl(meth)acrylate, acetoacetoxypropyl(meth)acrylate, acetoacetoxybutyl(meth)acrylate, 2,3-di(acetoacetoxy)propyl(meth)acrylate, allyl acetoacetate, and vinyl acetoacetate; acetoacetamidoethyl(meth)acrylate, acetoacetamidopropyl(meth)acrylate, acetoacetamidobutyl(meth)acrylate, 2,3-di(acetoacetamido)propyl(meth)acrylate, allyl acetoacetamide, and vinyl acetoacetamide; cyanoacetoxyethyl(meth)acrylate, cyanoacetoxypropyl(meth)acrylate, cyanoacetoxybutyl(meth)acrylate, 2,3-di(cyanoacetoxy)propyl(meth)acrylate, allyl cyanoacetate, and vinyl cyanoacetate; cyanoacetamidoethyl(meth)acrylate, cyanoacetamidopropyl(meth)acrylate; cyanoacetamidobutyl(meth)acrylate, 2,3-di(cyanoacetamido)propyl(meth)acrylate, allyl cyanoacetamide, and vinyl cyanoacetamide.