Patent ID: 8153721
Filing Date: 2012-04-10
Classification: C08F,C08L,C09D,C09J

Abstract:
1. A process for the preparation of an aqueous polymer dispersion comprising polymerizing, by free radical aqueous emulsion polymerization, ethylenically unsaturated monomers in the presence of at least one dispersant and at least one initiator, wherein the ethylenically unsaturated monomers comprise a monomer A and a monomer B, the monomer A is included in an amount of from 0.1 to 10% by weight of a total amount of the ethylenically unsaturated monomers, the monomer A is at least one ethylenically unsaturated monomer having a solubility of ≧200 g per 1000 g of demineralized water at 20° C. and 1 atm (absolute), the monomer B is included in an amount of from 90 to 99.9% by weight of the total amount of the ethylenically unsaturated monomers, the monomer B is at least one ethylenically unsaturated monomer having a solubility of ≦100 g per 1000 g of demineralized water at 20° C. and 1 atm (absolute), the monomer A and the monomer B sum to 100% by weight, the polymerizing includes polymerizing only from 0.1 to 10% by weight of the total amount of the monomer B in an aqueous polymerization medium at a polymerization stage 1, and thereafter adding the total amount of the monomer A and the remaining amount of the monomer B to the aqueous polymerization medium to polymerize the monomer A and the monomer B under polymerization conditions at a polymerization stage 2.