METHOD FOR MOLDING RESIN MOLDING

摘要

PROBLEM TO BE SOLVED: To provide a molding method which can produce a polymer resin molding having high crystallinity through a relatively simple process high in the degree of freedom of a shape.

SOLUTION: A molten crystalline polymer resin A' is packed in a cavity 15' surrounded by a fixed mold 12 and a movable mold 13 which constitute a mold. A physical blowing agent and a second blowing agent with the integrated amount of generated gas increased with the passage of time are mixed into the molten resin. While the temperature of the molten resin is kept between the melting point and the crystallization temperature of the resin, the movable mold is core-backed in the direction to be separated from the fixed mold to increase the volume of the cavity, and the polymer resin in the cavity is molded while being expanded by the physical blowing agent and the second blowing agent. The molten resin is oriented by making stretch distortion occur in the molten resin at a velocity of at least a critical stretch distortion velocity during the molding of the resin and crystallized by keeping the state to produce the resin molding.

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