EXPANDABLE POLYSTYRENE RESIN BEADS, PROCESS FOR THE PREPARATION OF THEM, AND FOAM MADE BY USING THE SAME

摘要

PURPOSE: Provided are foamable modified polystyrene resin particles, a process for preparation thereof and a foamed article which is produced by using the foamable modified polystyrene resin particles and has excellent break resistance. CONSTITUTION: Expandable modified polystyrene resin beads (E) is prepared by incorporating a blowing agent (D) into beads of a modified polystyrene resin (C) comprising a polystyrene resin (A) and conjugated diene polymer rubber particles (B) homogeneously dispersed in the resin (A), which beads have such a property that the rubber particles (B) do not undergo any substantial change in the shape during the expansion; and a modified polystyrene resin foam which has cell walls made of a modified polystyrene resin comprising a polystyrene resin and conjugated diene polymer rubber particles dispersed in the resin and a rate of fusion of 50 % or above and in which the rubber particles substantially retain their globular shapes in the cell walls. The foam is equivalent to high-impact polystyrene foams in both crack resistance and rate of fusion and is inexpensive.