| 摘要 |
1,121,409. Moulding cellular articles. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 29 Dec., 1966 [31 Dec., 1965], No. 58163/66. Heading B5A. Smooth skinned, void free, cellular articles are made from a polyvinyl aromatic compound, such as polystyrene, by extruding an expanded sheet having 85% by volume of closed cells and a shrink of at least 5% under standardized conditions; comminuting the sheet, by for example chipping or cutting, in such a way as to preserve the cellular structure; and finally sintering the resultant particles in a closed mould, care being taken that at least 1% of organic liquid blowing agent is present in the mould per 20% shrink. The material used may or may not be scrap and if the residual blowing agent content is not up to the desired level more agent may be added after as a liquid before or after comminution or as a vapour in which the particles are stored. The shape and colour of the particles may be varied to produce decorative effects. Elastomeric material such as natural or synthetic rubber may be added to the aromatic compound. |
