| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a chromium-free precoated steel sheet excellent in all of raindrop fouling resistance, planar-part corrosion resistance and precoated film formability and to provide a housing suitable for outdoor use. <P>SOLUTION: The chromium-free precoated steel sheet includes a laminated precoated film composed of at least two layers on one surface of a steel sheet constituted of a zinc-based plated steel sheet as a base material. An upper coating film forming the outermost layer of the laminated coating film has ≤60° water contact angle, ≤40°C Tg (glass transition temperature) and 4-25 μm thickness, is made from mainly a polyester resin having ≥10,000 average molecular weight, and contains a color pigment and a rustproof pigment, the total content of both of which is ≤60 mass% of the solid content of a coating material. A lower coating film forming the innermost layer of the laminated coating film has ≤40°C Tg and 2-10 μm thickness, is made from mainly a polyester resin having ≥10,000 average molecular weight, and contains the color pigment and the rustproof pigment, the total content of both of which is ≤10 mass% of the solid content of the coating material. <P>COPYRIGHT: (C)2012,JPO&INPIT |
