Method of making expandable styrene-type beads
AssigneeAmerican Hoechst Corporation
InventorsJames E. Millington, Stelvio Papetti
Life of this patent
Estimating the term…
Abstract
Expandable 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 molecuar weight of at least 1,000, and by subsequently washing and drying the beads.
Claims5
A method of making expandable styrene-type polymer beads wherein the polymer beads are impregnated 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 nonionic 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 then washed with water and dried.
Dependencies are inferred from the claim text.