| abstract |
The present invention provides a coated steel sheet excellent in corrosion resistance and coating film adhesion, in which the coating film secondary adhesion of a processed part does not decrease even when water acts. SOLUTION: A water-soluble metal complex compound [eg, Fe (acac) 2 (H 2 O) 2 ], which changes into poorly soluble upon heating and drying on a zinc-based plated steel sheet, an oxazoline group-containing crosslinkable resin, and a silane coupling A chemical conversion treatment layer is formed by application of an aqueous chemical conversion treatment solution containing an agent and not containing hexavalent chromium and heat drying, and a polyester-based undercoat film and topcoat film are formed thereon. The aqueous chemical conversion treatment liquid may further contain at least one compound selected from the group consisting of silica, zirconium compounds, and citric acid and salts thereof. [Selection] Figure 1 |