Patent ID: 8445559

Claim:
A polymeric particle comprising a core, a first shell, and a second shell: said core comprising, when dry, at least one void; said first shell polymer having a calculated glass transition temperature(“Tg”) greater than 50° C. and comprising, as polymerized units, from 15% to 60%, by weight based on the weight of said first shell polymer, monomer selected from the group consisting of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and mixtures thereof; and from 0.3% to 10%, by weight based on the weight of said first shell polymer, multiethylenically unsaturated monomer; and said second shell polymer having a Tg of from −60° C. to 50° C.; wherein the weight ratio of said second shell polymer to the total of all other structures of said polymeric particle is from 0.5:1 to 3:1.