Nisshin Steel Co., Ltd.

Hirokazu Yano

Kazuhiko Takahashi

Taketo Hara

Kenji Sakato

Kiyoshi Takatsu

Yoshikatsu Udagawa

Minoru Kiyotsuka

This coated metal plate is a chromate-free coated metal plate for exterior applications, which comprises a metal plate and a coating film that is arranged on the metal plate. The coating film contains 0.2-15 vol % of porous particles as a gloss control agent, and contains 0.2-15 vol % of primary particles as a matting agent. If R1 (&#x3bc;m) is the number average particle diameter of the gloss control agent, R2 (&#x3bc;m) is the number average particle diameter of the matting agent, T (&#x3bc;m) is the film thickness of the coating film, &#x3c3;1 (&#x3bc;m) is the standard deviation of the number-based particle size distribution of the gloss control agent and &#x3c3;2 (&#x3bc;m) is the standard deviation of the number-based particle size distribution of the matting agent, the coated metal plate satisfies the following formulae.(1+2&#x3c3;1)/&#x2264;0.71&#x2265;2.02.0&#x2264;(2+2&#x3c3;2)/&#x2264;7.013&#x2264;&#x2264;20.

Coated metal plate and exterior building material

This coated metal plate is a chromate-free coated metal plate for exterior applications, which comprises a metal plate and a coating film that is arranged on the metal plate. The coating film contains 0.01-15% by volume of porous particles as a gloss control agent. If R (&#x3bc;m) is the number average particle diameter of the gloss control agent, T (&#x3bc;m) is the film thickness of the coating film, and &#x3c3; is the standard deviation of the number-based particle size distribution of the gloss control agent, the coated metal plate satisfies the following formulae. (R+2&#x3c3;)/T&#x2264;0.7 R&#x2265;2.0 9&#x2264;T&#x2264;19.

A paint composition containing a corrosion inhibitor A prepared from porous silica particles, to which Ca ion is bonded by ion-exchange, and a polyphosphate B preferably at an A/B weight ratio of 60/40 to 5/95 and at an A+B ratio of 5-150 parts by weight based on 100 parts by weight of resinous components. A base metal sheet is preferably one pre-treated with a chemical agent containing at least one fluoroacid. Since the polyphosphate B controls dissolution of Ca ion, an effect of Ca ion on corrosion inhibition is maintained over a long term. The painted metal sheet does not put harmful influences on the environment, since it does not contain chromium compounds.

Growing community of inventors

Chiba, Japan

Hirokazu Yano