| abstract |
Electrically conducting mouldings are made by providing plastic granules with conductive coatings, e.g. of carbon, silver, copper or nickel, and moulding under heat and pressure, e.g. into plates or rods. The granules may be produced by powdering or cutting, by drying drops of a solution or by suspension polymerization. The conductive coating may be applied by precipitating metals from solutions by reducing agents, by precipitating from suspensions or, in the case of carbon and copper powders, by rubbing, e.g. in a ball mill using wooden balls. In examples, granular polystyrene is (1) treated with a silvering solution; (3) nickel-plated with an ammoniacal nickel acetate solution containing hydrazine hydrate and potassium platinum chloride as catalyst; (4) rubbed together with graphite at 150 DEG C.; (2) polymethyl methacrylate grains are copper-plated with an ammoniacal copper acetate solution containing hydrazine hydrate; (5) urea-formaldehyde moulding powder is rubbed together with carbon powder; (6) butadiene-acrylonitrile copolymer granules containing zinc oxide, sulphur, tetramethyl thiuram disulphide, stearic acid and dibutyl phthalate are rubbed together with graphite powder; (7) plasticized granular polyviny chloride is rubbed with colloidal graphite; (8) granular alkaline aldehyde-cresol resin containing hexamethylene tetramine is rubbed with graphite.ALSO:Plastic granules are provided with conductive coatings and subsequently mould under heat and pressure. The coatings may be applied by precipitating metals from solutions by reducing agents or from suspensions, or by rubbing together the plastic and metal powders, e.g. in a ball mill using wooden balls. In examples, granular polystyrene is (1) treated with a silvering solution; (3) nickel-plated with an ammoniacal nickel acetate solution containing hydrazine hydrate and potassium platinum chloride as catalyst; (2) polymethyl methacrylate grains are copper-plated with an ammoniacal copper acetate solution containing hydrazine hydrate. Urea- and cresol-aldehyde resins, polyvinyl chloride and butadiene-acrylonitrile copolymer are also referred to. |