Chlorobutyl rubber-based high-impact polystyrene

Abstract

High-impact strength polystyrenes have been prepared which contain an included phase of polystyrene-grafted chlorobutyl rubber microgel. By use of a technique which involved precrosslinking the elastomer, monomer imbibement, a gel dispersal step, and a final suspension polymerization of the styrene monomer, products are produced having a high elastomer phase-to-elastomer ratio and suitable microgel particle size. These products have properties equivalent, in most respects, to commercial polybutadiene-based high-impact polystyrenes and have much improved resistance to outdoor aging.