| 摘要 |
PROBLEM TO BE SOLVED: To provide a precoated steel sheet having bending processability, weatherability and photocatalytic activity in good balance. SOLUTION: A colored organic coated film 2, an undercoat layer 3 and a photocatalytic layer 4 are successively laminated on a metal plate 1. In the colored organic coated film 2, a coloring pigment is dispersed in an organic base resin, and the undercoat layer 3 exhibits the elongation at break of 0.3 to 10% and contains, as the main component of a base resin, colloidal silica, a partially hydrolyzed/condensed material of an organo-alkoxy silane and a polymer or a copolymer of an unsaturated ethylenic monomer. The photocatalytic layer 4 exhibits the elongation at break of 0.3 to 10% and is formed by dispersing anatase-type TiO2 into a base resin having the same range of composition at that of the undercoat layer. In the undercoat layer 3 and the photocatalytic layer 4, the base resin having the composition of, by mass, 10-60% colloidal silica, 10 to 60% partially hydrolyzed/condensed material of the organo-alkoxy silane and 20 to 70% polymer or copolymer of the unsaturated ethylenic monomer is used. In the photocatalytic layer 4, the anatase-type TiO2 particles having an average particle size of <=200 nm is dispersed in an amount of 10 to 60% by mass based on the total coated film of the base resin and the TiO2. |
