COATING MATERIAL COMPOSITION AND COATED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To obtain a coating material composition capable of forming a coating film excellent in corrosion resistance and processability without using a chromate-based rust-preventive pigment and provide a coated steel sheet coated with this coating material composition. SOLUTION: This coating material composition contains 30-150 pts.wt. of a metal salt essentially comprising one or both of phosphoric acid and a condensed phosphoric acid, aluminum and magnesium as metal components and 3-50 pts.wt. of silica based on 100 pts.wt. of a polyester resin containing one or both compounds of ethylene oxide and propylene oxide with bisphenol A and having 2-20 mg KOH/g acid value. The coated steel sheet is obtained by coating this coating material composition on a zinc or zinc alloy galvanized steel sheet.