| 摘要 |
Compositions comprise one or more synthetic resins and at least 10 per cent by volume of a divided, non-sintered metal at least half of which is in the form of fragments, e.g. grains, chips, flakes and wires, having a minimum dimension greater than 0.14 mm. Specified resins are polyvinyl acetate, polystyrene, polyvinyl chloride, acrylic and methacrylic resins, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride terpolymers, polyesters, polyamides, urea-formaldehyde resins, phenol-formaldehyde resins and epoxy resins. Specified metals are bronzes, zinc, aluminium and alloys of aluminium, copper and magnesium. The compositions may also contain plasticizers, stabilizers, e.g. tribasic lead sulphate, dyes and powdered, fibrous or flaky fillers. The metal may be mixed with the resin dissolved in, or jellied with, a suitable solvent, e.g. methyl ethyl ketone and toluene, or mixed with powdered resin and the compositions moulded. Alternatively the metal may be mixed with a resin-forming liquid and catalyst and the mixture allowed to harden in a mould. The compositions may be used for making roofings, road signs, forming seals for metallic and other articles, and for thermal, electrical and acoustic insulation. When the proportion of metal is high, e.g. above 95 per cent, porous products are obtained which may be used as filters. |
