| 摘要 |
PROBLEM TO BE SOLVED: To provide a rust-preventive coating composition capable of forming, without containing a chromium-based rust preventive pigment, a coating film excellent not only in the corrosion resistance of a general portion in a zinc-plated or zinc alloy-plated steel plate but also in the corrosion resistance of a processed portion or an end portion; and a coated metal plate using the same.SOLUTION: This rust-preventive coating composition for zinc-plated or zinc alloy-plated steel plate contains: (A) an amine-modified epoxy resin having a number-average molecular weight of 1,000-10,000, an amine value of 10-50 mgKOH/g, and a hydroxyl value of 180-280 mgKOH/g; (B) a hardener; and (C) a rust-preventive pigment. Based on 100 pts.mass of the total solid quantity of the amine-modified epoxy resin (A) and the hardener (B), in terms of solid quantity, the amine-modified epoxy resin (A) is 85-97 pts.mass, and the hardener (B) is 3-15 pts.mass. |
