Process for producing molded article having a hollow portion from a thermoplastic resin

摘要

A process for producing a hollow article (6) in an assembly comprising first (2) and second (3) mold members movable relative to each other between a closed position in which an inner surface of the assembly defines a cavity and an open position. The cavity is shaped to define a corresponding configuration to the article (6). According to this process, a charge containing at least one molten thermoplastic resin is supplied at the first and/or second mold member while the mold members are not in the closed position. The first mold member is moved relative to the second mold member into the closed position so as to define the cavity, and a first clamping force F1 is applied to the first and second mold members. The charge is then compressed within the mold cavity under the first clamping force F1. Thereafter, the clamping force is reduced from the first clamping force F1 to a second clamping force F2 before the molten thermoplastic resin in the mold cavity has completely solidified. A compressed gas is supplied into at least one unsolidified portion (4) of the molten thermoplastic resin subsequent to the step of closing the mold members and before the molten thermoplastic resin in the mold cavity has completely solidified. The molten thermoplastic resin can then be cooled in the mold cavity and solidified while supplying the compressed gas.