| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a chromium-free surface-treated galvanized steel sheet which has a surface treatment film with a two-layer structure comprising an underlayer as a bonding layer formed by a coating agent containing a silane coupling agent and an upper coating layer thereon, and has satisfactory corrosion resistance. SOLUTION: The method for manufacturing the chromium-free surface-treated galvanized steel sheet having a bonding layer formed on the galvanized steel sheet by the coating agent containing an organic resin, the silane coupling agent and a corrosion inhibitor, and a functional organic coating layer formed thereon by a coating agent for forming the functional organic coating layer, comprises applying the coating agent for forming the bonding layer on the galvanized steel sheet or a zinc alloy-plated steel sheet to form the coating film, baking the coating film at 50 to 200°C, and subjecting the cured coating film to water cooling treatment and alkali cleaning treatment to form the bonding layer, wherein the alkali cleaning treatment is performed at cleaning bath conditions of pH 9 to 12 and 70°C or lower. COPYRIGHT: (C)2004,JPO&NCIPI
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