Patent ID: 9169380
Filing Date: 2015-10-27
Classification: C08L,C09D

Abstract:
1. A method for preparing a coating composition, the method comprising, polymerizing a monomer composition 1 comprising a first monomer comprising an ethylenically unsaturated group, an adhesion monomer that is different from the first monomer and that comprises an ethylenically unsaturated group and nitrogen, and a further monomer that is different from the first monomer and that is selected from the group consisting of itaconic acid, acetoacetoxyethyl (meth)acrylate (AAEM), acrylonitrile, and a combination thereof by radical aqueous emulsion polymerization to a conversion of at least 90, based on the monomer composition 1 to be polymerized to yield a polymer 1, and subsequently, in the presence of the polymer 1, polymerizing a monomer composition 2 comprising a second monomer comprising an ethylenically unsaturated group, optionally an adhesion monomer that is different from the second monomer and that comprises an ethylenically unsaturated group and nitrogen, and a further monomer that is different from the second monomer and that is selected from the group consisting of itaconic acid, acetoacetoxyethyl (meth)acrylate (AAEM), acrylonitrile, and a combination thereof by radical aqueous emulsion polymerization, to obtain an aqueous polymer dispersion wherein the monomer composition 1 is such that random copolymerization of the composition 1 alone would give a polymer 1 with a glass transition temperature Tg1>0° C.; the monomer composition 2 is such that random copolymerization of the composition 2 alone would give a polymer 2 with a glass transition temperature Tg2>80° C.; the difference between Tg1 and Tg2 is at least 50° C.; the adhesion monomer is copolymerized in an amount of from 0.1% to 10% by weight, based on the total amount of monomers polymerized; of the total amount of the adhesion monomers to be copolymerized, from 20 to 100 mol % are copolymerized in the polymerizing of monomer composition 1; the polymer of composition 1 or the polymer of composition 2 having a lower glass transition temperature is present in an amount of from 60% to 90% by weight; and the further monomer which is different from these monomers and is selected from the group consisting of itaconic acid, acetoacetoxyethyl (meth)acrylate (AAEM), and acrylonitrile is copolymerized in an amount of from 0.2% to 25% by weight, based on the total amount of the monomers to be polymerized.