| 摘要 |
PROBLEM TO BE SOLVED: To eliminate mold stain or aging deterioration of a mold release resistance without 'burn', 'void' or hydrolysis by heating to dry a material previously under reduced pressure, then melting the material in the state of supplying inert gas, and injecting the material in a mold. SOLUTION: A material pellet 8 is heated by a heater 22 in a chamber 21, pressure reduced and degassed by a vacuum pump. Then, the chamber 21 is pressure reduced to 200 Torr or below. The drying temperature is desirably set to a temperature lower by 20 to 40 deg.C from a glass transition point of the material, and the drying time is preferably set to 1 to 8 hours. The dried material pellet 8 is dropped in a heating cylinder 1 filled with inert gas through a material feed tube 30 and a hopper 15. There, when the pellet 8 is heated and melted, the pellet 8 is simultaneously kneaded and metered by rotary retracting of a screw 2, and thereafter injected in a mold by forwarding the screw 2 and molded.
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