| 摘要 |
PROBLEM TO BE SOLVED: To provide a coating method, which generates little environment problem such as waste water treatment, and can improve corrosion resistance of a metal material coated with water paint. SOLUTION: This coating method comprises subjecting a metal material to normal pretreatment such as degreasing; treating it with a phosphate conversion coating solution of pH 3 to 4.5 (a chemical conversion coating process), which contains phosphate ions and nitrate ions as main components and further zinc ions of 100-300 ppm; and then, with or without film forming treatment before coating, applying a thermosetting water-paint composition (a coating process), which is manufactured from a raw material containing 10-70 mass% of monofunctional monomers having a 6-18C alkyl chain, and which includes a water-soluble polyester resin with number average molecular weight of 1,000-10,000, acid value of 20-80 and hydroxyl value of 50-200 and a curing agent, on a formed film by the chemical conversion coating.
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