METHOD OF MAKING EXPANDABLE STYRENE-TYPE POLYMER BEADS

摘要

Expendable styrene-type polymer beads having a short cooling time are made by impregnating the polymer beads, after the substantial completion of the polymerization, in an aqueous suspension medium comprising a suspending agent and about 0.005 - 0.3%, based on the weight of water, of non-ionic surfactant which is a copolymer of propylene oxide and ethylene oxide having an HLB number of 8 - 18 and an average molecular weight of at least 1,000, and by subsequently washing and drying the beads.