ORGANIC-COATED STEEL SHEET EXCELLENT IN CORROSION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide an organic-coated steel sheet capable of giving excellent corrosion resistance without incorporation of heavy metal such as sexivalent chromium into a film. SOLUTION: An organic film of 0.1-5μm film thickness is formed on the surface of a galvanized steel sheet or an aluminum-coated steel sheet. This organic film contains a reaction product of film forming organic resins (A) and active-hydrogen-containing compounds (B) where a part or all of the compounds are composed of hydrazine derivatives (C) having active hydrogen and an ion exchange silica (a), and the content of the ion exchange silica (a) is regulated to 1-100 pts.wt. (solid content) based on 100 pts.wt. (solid content) of the reaction product.