| 摘要 |
PROBLEM TO BE SOLVED: To improve a surface appearance of a molding by previously pressurizing a mold cavity by a gas to a pressurized state and injecting a molten resin lowered at its melt viscosity by dissolving a specific amount of a carbon dioxide in the cavity in injection molding of an aliphatic polyketone. SOLUTION: In the case of injection molding an aliphatic polyketone having excellent mechanical characteristics, chemical resistance, barrier properties or the like and having disadvantages of a decrease in flowability when molded at a low temperature and a deterioration of a surface appearance, it is treated to inject a molten resin lowered at its melt viscosity by dissolving a carbon dioxide of 0.2 wt.% or more in a mold cavity by previously pressurizing the cavity to a pressure or higher for bringing about no foaming at a flow front of the resin by a gas to a pressurized state. Thus, charging of the resin in the cavity is facilitated so that a surface state of the mold can be highly transferred to a surface of a molding. As the polyketone to be used, a copolymer made of an aliphatic olefin and a carbon dioxide is used.
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