| 摘要 |
PROBLEM TO BE SOLVED: To provide a chromium-free surface-treated steel sheet having excellent planar part and corrosion resistance after working even in the case of being alkali-degreased or exposed to a corrosive environment over a long period by a user. SOLUTION: On the surface of a galvanized steel sheet or an aluminum-plated steel sheet, a surface treatment film by a surface treatment composition obtained by compositely adding an organic phosphoric acid compound, a vanadic acid compound, a zirconium fluoride compound and a zirconium carbonate compound at a prescribed ratio to a titanium-based aqueous liquid obtained by mixing a predetermined titanium compound with a hydrogen peroxide solution is formed, and further, the upper layer thereof is provided with an upper layer film formed by applying a coating material composition obtained by blending a predetermined crosslinking agent into a resin obtained by modifying a predetermined epoxy resin with a soft component and further reacting the same with an active hydrogen-containing hydrazine derivative and further preferably blending a non-chromium base rust-proofing additive therein and drying the coating material composition. COPYRIGHT: (C)2010,JPO&INPIT |
