| 摘要 |
1,235,293. Electro-phoretic coating. CANADIAN INDUSTRIES Ltd. Dec.30, 1968 [Dec. 12, 1967], No.56426/67. Heading C7B. [Also in Division C3] Conductive articles are coated by cathodic deposition using a water-borne cross-linkable coating composition which comprises a blend of (a) a polymer containing a carboxylic acid group and a pendant amine group and (b) an epoxidized material, or a pre-condensate of (a) and (b) or a pre-condensate of materials which contain a carboxylic acid group, a pendant amine group and an epoxide group. There is present in the composition at least one epoxide group for each carboxyl group and the composition is dispersed in sufficient proton-donating acid, e.g. H 3 PO 4 , to provide 0À5-1À0 equivalents of said acid for each amine group present. The blend may comprise (a) a copolymer of an ethylenically unsaturated carboxylic acid and a dialkyl aminomethyl methacrylate, and (b) a condensation product of epichlorohydrin and bisphenol A. An alternative composition comprises a condensate of a drying oil fatty acid, and aminocarboxylic acid and epoxidized polybutadiene. The composition may be dissolved in an organic solvent prior to dispersion in water. In electro-deposition, the article to be coated serves as the cathode which is in electrical contact with another electrode serving as anode. A voltage of 12-300 volts may be applied. The coated article may be crosslinked by heating, e.g. at 100-150‹ C. |
