CLEAR COAT STEEL PLATE HAVING SUPERIOR RESISTANCE AGAINST END FACE RUSTING

摘要

PROBLEM TO BE SOLVED: To suppress end face rusting of an Cr-free clear coat steel plate having one or more layers of clear coat films on at least one surface of a zinc-based or aluminum-based plated steel sheet, and preferably to further prevent copper corrosion.

SOLUTION: A clear film of an outermost layer contains (A) a resin composed of one kind or two kinds selected from a group comprising an acryl-based, a polyseter-based, and an urethane-based resin and having a glass transition temperature of -10°C or higher, (B) silica having a mean particle size of 0.1 μm or larger and an oil absorption amount of 50 mg/L or larger, and (C) a Zr compound or a silane coupling agent, wherein A, B and C representing contents of the components (A), (B), and (C) (in terms of mass.%) to the total film solid content respectively, satisfy the following relation expression: B is ≥1% and ≤20%; C/A is 0.05 or larger and less than 0.35. Here, C/A is a mass ratio of the component (A) to the component (C). The content of the Zr compound of the component (C) is an amount in terms of ZrO2.

COPYRIGHT: (C)2013,JPO&INPIT