SURFACE-TREATED STEEL SHEET EXCELLENT IN ALKALI RESISTANCE

摘要

PROBLEM TO BE SOLVED: To produce a surface-treated steel sheet which is prepared by forming a film excellent in roll forming properties, external appearance after roll forming, and resistances to alkali and corrosion on the surface of an aluminum- containing-zinc plated steel sheet. SOLUTION: This surface-treated steel sheet is prepared by forming a film mainly comprising a resin containing acid amide bonds on the surface of an aluminum-containing-zinc plated steel sheet. Preferably, the resin containing acid amide bonds is a urethane resin containing acid amide bonds. Preferably, a chromium compound as an additional component is incorporated into the film mainly comprising a resin containing acid amide bonds. The wt. ratio (resin/Cr) of the solid component of the resin to the chromium compound (in terms of metallic chromium) is preferably in the range of 1-200. The chromium content in the film (in terms of metallic chromium) is preferably in the range of 1-100 mg/m<2> .