Patent ID: 8679294
Filing Date: 2014-03-25
Classification: B01J,C08L,D21H,Y10T

Abstract:
1. A method of forming an expandable microsphere comprising: mixing primary monomers selected from nitrile containing monomers, acrylic ester monomers, methacrylic ester monomers, vinyl esters, vinyl halide monomers and combinations thereof, at least one blowing agent, a crosslinking monomer, a polymerization initiator, and a stabilizer system in a reaction vessel for a period of time sufficient to achieve an approximate 90% polymerization of said primary monomers and form a first polymeric layer surrounding said blowing agent; and adding a secondary monomer selected from monomers having a Tg of at least 85° C. and chemically reactive monomers to said reaction vessel to form a second polymeric layer at least substantially surrounding said first polymeric layer and forming an expandable microsphere.