METHOD OF INJECTION MOLDING EXPANDABLE PLASTIC COMPOSITION

摘要

A process for the injection molding of a foamable plastic composition which comprises the steps of injecting a molten foamable plastic composition into a cavity having a lower volume than that of a desired molded article; after the completion of injection filling, cooling the composition to the state wherein a solidified layer in contact with a mold surface mingles with a molten inside layer; enlarging the volume of the cavity to that of the desired molded article; and after further cooling, removing the molded article. This molded article comprises a layer having a non- or low-foamed, dense structure on the surface and a high-foamed layer at the inside, and has a light weight and good thermal insulating properties. <IMAGE>