SURFACE TREATING AGENT FOR GALVANIZED STEEL SHEET, AND SURFACE TREATED GALVANIZED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide a surface treating agent requiring no particular waste water treatment in the course of steel sheet manufacturing process and during use and capable of forming a surface treatment film particularly excellent in corrosion resistance in working area as well as in adhesion on a steel-sheet surface, and a steel sheet having a film formed by using the surface treating agent. SOLUTION: The surface treating agent for galvanized steel sheet contains a water soluble copolymer having hydroxyl-group-containing monomer and carboxyl-group-containing monomer and a water soluble polymer having phosphoric-acid-group-containing monomer or contains a water soluble copolymer having hydroxyl-group-containing monomer, carboxyl-group-containing monomer, and 2 wt.% phosphoric-acid-containing monomer. The surface treated galvanized steel sheet has a film formed by using the surface treating agent for steel sheet at least on one side.