Patent ID: 6497269
Filing Date: 2002-12-24
Classification: C08F

Abstract:
A method for forming an expandable styrenic copolymer, comprising:providing polymeric seeds in an aqueous medium; combining with the polymeric seeds, in the aqueous medium, a suspending agent and one or more surfactants in a ratio of about 1:175 or less to the weight of suspending agent, to form a seed mixture; providing a monomer mixture comprising from about 50 to about 90 percent by weight of one or more acrylic monomers, from about 10 to about 50 weight percent of one or more styrenic monomers, and one or more initiators; combining the monomer mixture with one or more expanding agents to form a reaction mixture; combining the seed mixture with about 100 to about 2500 weight percent of the reaction mixture, based on the weight of the seeds in the seed mixture, of the seed mixture to form a polymerization mixture; and heating the polymerization mixture to a polymerization temperature to effect formation of the copolymer.