| 摘要 |
1483055 Ceramics FOSECO INTERNATIONAL Ltd 18 Oct 1974 [12 Nov 1973] 52449/73 Heading C1J A replica of a body of reticulated organic foam consists wholly or substantially of ceramic fibres, which can be bonded together by heating or by the dried residue of an oxide hydrosol (e.g. of alumina or silica) or other inorganic refractory binder (e.g. aluminium hydrogenorthophosphate, aluminium chromium hydrogenorthophosphate, a suitable chromium salt, zirconium hydroxy-nitrate, zirconium hydroxyacetate, phosphoric acid or aluminium hydroxychloride). Fibres are glass wool, slag wool, asbestos, SiO 2 , aluminosilicate, Al 2 O 3 , ZrO 2 or glass ceramics, while the foam may be polyurethane. The ceramic replica may be employed as a support for catalysts; accordingly, therefore, there may be an addition of catalytic material in particulate form during the preparation of the ceramic replica, but any non- fibrous particulate matter present in the ceramic replica must make no significant contribution to the strength thereof. The ceramic replica may be prepared by impregnating a body of reticulated organic foam with a slurry of finely divided inorganic fibres and drying and firing the so-impregnated body. In a preferred alternative procedure, a reticulated polyester polyurethane foam is pretreated with a base, preferably a volatile organic base, e.g. monoethanolamine, and the polyurethane body is then plunged into a slurry of short ceramic fibres in an aqueous solution of a modified polyvinyl polycarboxylic acid of a type whose solutions undergo a sharp viscosity increase when neutralized. The resulting body is centrifuged, dried and fired. If preferred, the steps of dipping into the slurry and centrifuging may be repeatedly carried out until the desired coating thickness is built up. |
