Handle-shaped molded article, method of injection molding thereof and mold for the injection molding.

摘要

A method for producing a handle-shaped molded article (1) having a thick grip portion (2) and at least one thick fitting portion (3) by injection molding uses an injection molding apparatus (10) equipped with a mold having a cavity (60), a resin gate (46) provided in a portion (62) where the fitting portion is to be formed and a gas inlet (48) provided in a portion (64) where the grip portion is to be formed; and a hollow structure (4) is formed in the grip portion (2) and a solid structure is formed in the fitting portion (3) by injecting a molten resin into the cavity (60) through the resin gate (46), thereby filling molten resin in a fitting portion-forming cavity zone formed of that portion (62) of the mold where the resin gate is provided and the fitting portion is to be formed and further filling molten resin in part of the rest of the cavity, introducing a pressurized gas into the cavity (60) through the gas inlet (48) while maintaining an injection pressure, P, at a predetermined value, the injection pressure, P, being defined by <MATH> wherein P is an injection force and S is a cross-sectional area of a screw (12) of the injection molding apparatus, and maintaining the injection pressure and a gas pressure in the gas inlet (48) at predetermined values until the molten resin is cooled and solidified. <IMAGE>