| 摘要 |
1,120,221. Moulding foamed plastics. CHELLINGWORTH & SINGER Ltd. 22 July, 1965 [23 April, 1964], No. 16959/64. Heading B5A. A method of reproducing a copy of a master pattern, comprises the steps of producing a plaster east or similar negative of the master, placing the negative in a mould or using it as a mould covering the internal surfaces of the negative with a release covering, e.g. metal foil, filling the mould with foamable plastics material, causing the plastics to expand and set and removing the cast plastics body. The plastics may be prefoamed polystyrene beads or a polyurethane mixture and heated by steam or other hot gas introduced through perforated pipes inserted through holes in the mould. The plastics body may be used to make a further mould, e.g. a foundry mould from which copies of the master are cast. |
