| 摘要 |
1480897 Panel core material PLASTONIUM Ltd 9 Sept 1974 [11 Sept 1973] Addition to 1,281,381 42709/73 Heading ClH [Also in Division B5] A material for forming core layers in fireresistant constructional panels comprises a mixture of alkaline earth metal (e.g. Ca, Mg, Ba) sulphate and finely-divided or pulverent carbon, whereby at least part of the core reacts at elevated temperature to yield an alkaline earth metal sulphide, e.g. as a surface layer. The sulphate is preferably gypsum, plaster of Paris or anhydrite and the carbon particles may be anthracite, coke, coal dust, soot or C black of size less than 500 microns. There may be 1 part carbon per 10-100 parts sulphate. The core may include polyvinyl acetate, epoxy, melamine or styrene resin and fillers, e.g. expanded perlite, expanded vermiculite, mica, asbestos, quartz, silica, CaCO 3 and glass, sisal, wood or jute fibres, and may be foamed by frothing or by a blowing agent. In an example, a sheet is cast from a mixture of plaster of Paris (100 parts), perlite (25 parts), wood fibre (2 parts), coal dust (1À8 parts), polyvinyl acetate emulsion (12À3 parts), coal dust (1À8 parts), polyvinyl acetate emulsion (12À3 parts) and water. |
