POLYSTYRENE-CONTAINING COMPOSITE RESIN PARTICLES AND METHOD FOR PRODUCING SAME, EXPANDABLE COMPOSITE RESIN PARTICLES, PRE-EXPANDED PARTICLES, AND EXPANDED MOLDED ARTICLE

摘要

Polystyrene-containing composite resin particles each comprising 100 parts by weight of an ethylene-(vinyl acetate) copolymer resin and 100 to 500 parts by weight of a polystyrene-type resin. When an extract (A) is produced by impregnating the composite resin particles with a volatile expanding agent, then pre-expanding the impregnated composite resin particles to produce pre-expanded particles and then immersing the pre-expanded particles in tetrahydrofuran for 24 hours, an extract (B) is produced by halving each of the pre-expanded particles at the center thereof to produce halved products and then immersing the halved products in tetrahydrofuran for 24 hours, and chromatograms for the extracts (A) and (B) are produced by subjecting the extracts (A) and (B) to a GPC measurement, the ratio (Ps:Pi) of the top intensity of a peak, which is a peak of a polystyrene resin having an weight average molecular weight of 100,000 to 500,000 and is produced from each of the chromatograms, in the chromatogram for the extract (A) to that for the extract (B) or the ratio (Ss:Si) of the area of the peak in the chromatogram for the extract (A) to that for the extract (B) is 1:10 or more in the chromatograms for the extracts (A) and (B).