| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for molding a thermoplastic resin foam, in which foaming in the inside of a screw cylinder is suppressed and fine foams having high quality are obtained. SOLUTION: When the thermoplastic resin foam is obtained from a plasticization process, in which a screw 20 is rotated and driven to perform plasticization, and an injection process, in which inert gas, inert gas not lower than supercritical gas pressure at least in gas pressure or inert gas of a supercritical state is injected into a screw cylinder 1 and is penetrated into molten resin and the screw 20 is driven in the injection direction and the molten resin is injected into a mold, motor driven servomotors 31, 32 are used for drive of the screw 20. After the plasticization process is finished, a brake is applied to the motor driven servomotors 31, 32 and retreat of the screw 20 is stopped. Or, even after the plasticization process is finished, the screw 20 is driven at slow velocity in the direction of plasticization until just before the injection process begins. Thereby, foaming in the screw cylinder 1 is suppressed.
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