| 摘要 |
<p>1,131,351. Electro-phoretic deposition of zinc paint. DURHAM CHEMICALS Ltd. March 7, 1967 [March 9, 1966], No.10417/66. Heading C7B. A coating of zinc paint is deposited from an aqueous bath containing a water-soluble or waterdispersable resin as binder and a suspension of zinc flake of particle size below 60 microns, which zinc particles are formed with a protective coating of a water-insoluble non-polar or largely non- polar material, by passing an electric current through said bath using the substrate as the anode, and stoving the resulting coated substrate to insolubilize the binder. The zinc may contain an alloying constituent, e.g. magnesium, and the bath may also contain aluminium flake of particle size below 150 microns, similarly coated with coating material. The protective material used may be a solid hydrocarbon or hydrocarbon derivative having fatty or waxy properties, e.g. lauric, stearic, myristic, palmitic and oleic acids and corresponding esters and alcohols. The resin forming the binder may be a watersoluble modified alkyd or amine resin or epoxy ester of a fatty acid. The bath may also contain a non-ionizing water-soluble cellulose ether, e.g. methyl cellulose or ethyl hydroxyethyl cellulose. Pigments which may be used include titanium dioxide, e.g. rutile coated with mixed oxides of zinc, aluminium and silicon, china clay, zinc oxide and barytes. The process may be carried out using a cell having the electrodes separated by a semi-permeable membrane, and a further layer of zinc or a layer of another metal, e.g. chromium or silver, may subsequently be electrolytically deposited upon the coated substrate.</p> |
