Patent ID: 6395836
Filing Date: 2002-05-28
Classification: C08F,C09D

Abstract:
A core/shell copolymer, comprising:(a) an acrylic copolymer A having a Tg of from 30Â° C. to 70Â° C. and formed from at least one hard monomer and at least one soft monomer; and (b) an acrylic copolymer B having a Tg of from 5Â° C. to âˆ’30Â° C. and formed from at least one hard monomer and at least one soft monomer; wherein said acrylic copolymer A is present at a level of from 5 to 40 weight %, based on the total weight of said first and second acrylic copolymers; wherein said acrylic copolymer B is present at a level of from 60 to 95 weight %, based on the total weight of said acrylic copolymers A and B; wherein said acrylic copolymers A and B contain units derived from same said hard monomer and same said soft monomer, wherein the total amount of said units derived from said hard monomer and soft monomer in each of said acrylic copolymer is at least 70 weight %, based on the weight of each acrylic copolymer; wherein said core/shell copolymer contains between 0.3 and 0.965 weight % of units derived from acid-functional vinyl monomers, based on the weight of said core/shell copolymer; and wherein said core/shell copolymer is prepared by a multi-step polymerization process.