Injection molding method

Abstract

Abstract PURPOSE:To easily obtain a molded item having widely expressible multi-layer construction by a method wherein a thin-walled preformed article is installed between a female mold and a male mold having a sprue so as to be expanded to the inner wall of the female mold by injecting molten synthetic resin through the sprue. CONSTITUTION:A preformed article 4 is capped in a male mold 1. Under the state just mentioned above, the male mold 1 and a female mold 2 are mated to each other. In this case, the flange part 4a of the preformed article 4 is pinched between the male mold 1 and the female mold 2 so as to be fixed. In succession, when molten synthetic resin 5 is injected through a sprue 3, the thin-walled preformed article 4 is pushed by the molten synthetic resin, resulting in swelling in the fashion of blow molding and expanding to the inner wall of the female mold. Thus, surface layer 4b is formed on the surface of synthetic resin core material 5b, resulting in forming a cap. Other working example is the application to a compact container. When a preformed article, which is formed by laminating transparent film 23, leaf-shaped printed layer 22 and adherent modified polyolefin layer 21 onto the transparent resin layer 20 in the order is molded similarly as described in the case of the cap, printed pattern is seen floating above the surface of the core material 5, regulating in bringing about a unique appearance.

Inventors

• 👤 Arihiro Onoda
• 👤 小野田　有弘
• 👤 Katsuro Taira
• 👤 平良　勝郎

Bibliographic Details