| 摘要 |
Cellular products are continuously manufactured from a mixture containing little or no blowing agent comprising a thermoplastic material, e.g. polyvinyl chloride, a finely-divided and uniformly distributed inert body, and a polyisocyanate which may react with water or water-vapour to form a gas, wherein, in a first stage a product having the embryonic shape of the desired final product and in a compact and cell-less state is continuously formed or extruded, the cells being formed during a second stage by the action of water or water vapour on the formed or extruded product. Inert bodies mentioned are silica or silicates, glass powder and cork. If the mixture contains polymerizable monomers, it is desirable to use a polymerization catalyst which does not give off a gas, e.g. benzoyl peroxide. Specifications 901,118, 921,068 and 985,461 are referred to. |
