| 摘要 |
820,966. Moulding foamed resin articles MONSANTO CHEMICAL CO. Oct. 22, 1956 [Oct. 20, 1955; Nov. 14, 1955], No. 32078/56. Class 87(2). [Also in Group VIII] An article having a layer of foamed synthetic resin with a thermo-plastic sheet on one or both sides e.g. a refrigerator panel, a container or a life belt is formed by placing a particulate foamable resin 10, e.g. polystyrene, on a perforated face 12 of a mould part 20, clamping a sheet 11 of e.g. polystyrene between the mould part 20 and shaped mould part 13, and then blowing steam into a jacket 14 to foam the resin and soften and force the sheet into contact with the mould part 13. Steam is also passed into the jacket 15. To form an article having a sheet of material on each side the foamable resin may be placed between two sheets (see Fig. 4, not shown) or steam may be blown through a pipe 19, Fig. 5, to force the thermoplastic sheet 11 into contact with the mould 13. In a modification (see Figs. 6 to 8, not shown) a thermo-plastic sheet may be preformed to the disired shape before being placed in the mould. A corresponding modification is described (see Fig. 10, not shown) for forming an article having a preformed sheet on both sides of the foam layer. The mould may be heated to such a temperature as to provide glossy surfaces on the thermoplastic sheet. The thermoplastic sheet may be made from methyl or ethyl cellulose, cellulose nitrate, acetate, butyrate, or acetatebutyrate, vinyl halides or other vinyl compounds, acrylic compounds, mixtures of polyvinyl chloride and butadiene-acrylonitrile interpolymers or polystyrene and natural rubber. The foamed resin may be thermosetting or thermoplastic e.g. phenol, urea or melaminealdehyde, methyl cellulose or cellulose acetate, vinyl compositions or acrylic compositions. Other resins are also specified. The foaming agent may be a volatile organic liquid e.g. pentane. An adhesive may be applied to the exposed surface of the thermoplastic sheet to provide a good bond between the sheet and the foamed resin.
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