METHOD FOR PRODUCING FOAMED THERMOPLASTIC RESIN COMPOSITION AND FOAMED THERMOPLASTIC RESIN COMPOSITION

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a foamed thermoplastic resin composition which can obtain the foamed resin composition of a high expansion ratio. SOLUTION: In injection molding, an expandable resin mixture is injected into the cavity of a mold having a mold expansion mechanism. The mixture contains 100 pts.wt. of a thermoplastic resin and 5-500 pts.wt. of a filler and added with a blowing agent. When the temperature in the middle in the thickness direction of the injected resin mixture in the cavity reaches a prescribed range, the mold is expanded.