SURFACE TREATMENT AGENT FOR ZINC OR ZINC ALLOY GALVANIZED STEEL SHEET, AND SURFACE TREATED ZINC OR ZINC ALLOY GALVANIZED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a nonchromium based surface treatment agent for a zinc or zinc alloy galvanized steel sheet capable of forming a film having excellent alkali resistance and solvent resistance, and additionally, having excellent corrosion resistance, fingerprint resistance, coating adhesion and blackening resistance.;SOLUTION: The surface treatment agent for the zinc or zinc alloy galvanized steel sheet is obtained by blending an aqueous medium with: (A) fluoroacid comprising fluorine atoms, and, titanium atoms, zirconium atoms or silicon atoms; (B) a phosphoric acid based compound selected from phosphoric acids and the ammonium salts thereof; (C) a silane coupling agent having an active hydrogen-containing amino group; (D) a silane coupling agent having an epoxy group bonded to the adjoining carbon atoms; (E) a cationic or nonionic urethane resin; and (F) a vanadium compound by specified amounts, respectively. The surface treated zinc or zinc alloy galvanized steel sheet is provided.;COPYRIGHT: (C)2007,JPO&INPIT