| 摘要 |
<p>1,129,302. Coating metal surfaces. YAWATA IRON & STEEL CO. Ltd. 6 Oct., 1965 [7 Oct., 1964], No. 42398/65. Heading B2K. [Also in Division C3] Metal surfaces are coated with a alkaline aqueous composition comprising a polymer, or polymer-cross linking agent mixture, containing alkoxymethyl group and at least one group selected from carboxyl or ammonium carboxylate, methylol and hydroxyl groups, and a water-soluble hexavalent chromium compound and then baked to react the alkoxymethyl groups with the other group(s) whereby an alcohol and/or aldehyde is liberated and reduces the hexavalent chromium, compound to a trivalent chromium compound. In the examples steel plates are coated with compositions containing a copolymer of styrene, acrylic acid and n-butyl acrylate, or of these three monomers with glycidyl methacrylate, diallyl phthalate or N-methylol acrylamide, a cross-linking agent selected from hexamethoxymethyl melamine, hexaallylated methylol melamine and di-N-methoxymethyl urea and a chromium compound selected from chromic acid or anhydride, ammonium chromate and zinc bichromate, other components of the composition being dibutyl phthalate and TiO 2 . Reverse roll and applicator coating machines are used. The steel plates which are coated may be galvanized and/or phosphate-treated, tin-coated, aluminiumcoated or copper-plated. Aluminium and copper plates may also be coated.</p> |
