| 摘要 |
<p>A protective coating composition for application to a ferrous or zinc containing surface, e.g. by brushing, spraying, dipping or flooding, followed by stoving, comprises an aqueous solution containing a copolymer of maleic anhydride with methyl vinyl ether, hydroxy ethyl cellulose, and phosphoric acid. The viscosity of the solution is between 50 and 100 centipoises and may include from 0.1 to 0.5% by weight of a non-ionic wetting agent. The corrosion resistance is improved by adding 1 to 5% by weight chromic acid or 1 to 3% ammonium dichromate. Alkali metal pyrophosphates (0.1 to 1.5% by weight) or 0.05 to 0.5% by weight of zinc pyrophosphate or sodium hexametaphosphate or tripolyphosphate may be added as accelerators. In an example a solution contains (parts per cent by weight) 1 of methyl vinyl ether maleic anhydride copolymer, 0.5 of hydroxy ethyl cellulose, 1 of ammonium dichromate, 2 of phosphoric acid, and 0.2 of an ethylene oxide condensate of nonyl phenol.ALSO:A protective coating is applied to a ferrous or zinc containing surface, e.g. by brushing, spraying, dipping or flooding, an aqueous solution containing a copolymer of maleic anhydride with methyl vinyl ether, hydroxy ethyl cellulose, and phosphonic acid which is then stoved. The viscosity of the solution is between 50 and 100 centipoises and may include from 0.1-0.5% by weight of a non-ionic wetting agent. The corrosion resistance is improved by adding 1-5% by weight chromic acid or 1-3% ammonium dichromate. Alkali metal pyrophosphates (0.1-1.5% by weight) or 0.05-0.5% by weight of zinc pyrophosphate or sodium hexametaphosphate or tripolyphosphate may be added as accelerators. In an example a solution contains (parts per cent by weight) 1 of methyl vinyl ether maleic anhydride copolymer, 0.5 of hydroxy ethyl cellulose, 1 of ammonium dichromate, 2 of phosphoric acid, and 0.2 of an ethylene oxide condensate of nonyl phenol.</p> |
