Title:
METHOD FOR PRODUCING EXPANSION MOLDED ARTICLE
Document Type and Number:
WIPO Patent Application WO/2010/070857
Kind Code:
A1
Abstract:
Disclosed is a method for producing an expansion molded article which contains a substantially non-foamed portion both in the inner part and in the surface. Specifically, an expansion molded article (W) containing a substantially non-foamed portion both in the inner part and in the surface is produced by injecting a molten resin which is obtained by impregnating a molten thermoplastic resin material with a supercritical fluid of either nitrogen or carbon dioxide. First of all, a cavity (C) is filled with a molten resin injected thereinto, and air bubbles (B) are formed in the whole molten resin in the cavity (C). Then, after the formation of the air bubbles (B), the molten resin is partially pressurized with a pressure higher than the critical pressure of the fluid, and the pressurization is maintained until the pressure of the molten resin falls below the above-mentioned critical pressure after the temperature of the molten resin has fallen to or below a temperature that is 70˚C higher than the glass transition temperature (Tg) of the resin material, so that the air bubbles (B) are eliminated in the pressurized region of the molten resin.
Inventors:
KOMATSU, Michio (14-6, Kusakidai 2-chome Iwaki-sh, Fukushima 01, 〒9728301, JP)
Application Number:
JP2009/006814
Publication Date:
June 24, 2010
Filing Date:
December 11, 2009
Export Citation:
Assignee:
KOMATSU, Michio (14-6, Kusakidai 2-chome Iwaki-sh, Fukushima 01, 〒9728301, JP)
International Classes:
B29C45/00; B29C45/56; B29C45/00; B29C45/56
Attorney, Agent or Firm:
SATO & ASSOCIATES (Nishi-Shinjuku Mitsui Building 18F, 24-1 Nishi-Shinjuku 6-chome, Shinjuku-k, Tokyo 23, 〒1600023, JP)
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