| 摘要 |
1,226,135. Injection moulding. CHEMISCHE WERKE HULS A.G. 9 Aug., 1968 [12 Aug., 1967], No. 38188/68. Heading B5A. Foamed plastics articles are produced by injecting a thermoplastic plastics composition containing an expanding agent into a mould cavity filled with fluid under a pressure of such magnitude sufficient to keep the composition in an unexpanded state during the injection stage, and controlling the escape of the pressure fluid from the cavity during the injection and expansion of the composition. The amount of composition injected corresponds to the desired weight of the moulded article. The fluid may be heated and the mould cavity pressure may be decreased to below atmospheric during the expansion of the composition. Pressure regulating valves may be connected to the mould cavity via passages and pipe connections. |
