Process for producing expandable thermoplastic resin beads

摘要

A process for producing expandable thermoplastic resin beads which comprises suspending in an aqueous medium 20 to 70% by weight of a random copolymer of propylene and ethylene containing 1 to 10% by weight of ethylene and 99 to 90% by weight of propylene and 30 to 80% by weight of a vinyl aromatic monomer such as styrene, polymerizing the vinyl aromatic monomer in the presence of a polymerization catalyst to graft the vinyl aromatic monomer onto the backbone of the random copolymer and, optionally, adding a cross-linking agent, to form graft-copolymerized thermoplastic resin beads, and introducing a blowing agent into the thermoplastic resin beads. The resulting resin beads have excellent foamability and molding fusability, and a foamed shaped article having superior thermal stability can be prepared from these beads.