| 摘要 |
1382274 Injection moulding cellular articles BRITISH UNITED SHOE MACHINERY CO Ltd 28 Jan 1972 [22 Jan 1971] 4119/72 Heading B5A A method of moulding an article of foam material comprises (a) mixing a moulding material and a blowing agent at a temperature below the foaming temperature, (b) injecting the mixture into a mould cavity and simultaneously increasing the temperature of the mixture at least to the foaming temperature, at a rate sufficient to fill the mould before the development of blowing gas, the surfaces of the mould cavity being at a temperature sufficient to cool the mixture adjacent thereto be below the foaming temperature but not to the solidification temperature of the moulding material, and (c) expanding the mould cavity and subsequently cooling the moulding mixture. The mould cavity may be expanded at a rate independent of the pressure in the cavity, exapnsion being commenced upon or immediately preceding termination of injection. Apparatus for carrying out the method is as described in Specification 1,292,318. |
