Nippon Steel Corporation

Asahi Denka Kogyo Kabushiki Kaisha

Hidehiko Kojo

Hiroshi Kanai

Joji Oka

The paint composition for under coating of the present invention comprises 60 to 90% by weight of an epoxy polyol resin optionally together with a hardener therefor and 10 to 40% by weight of silica particles. Said epoxy polyol resin is obtained by reacting an optionally substituted glycidyl-etherified product of an alkylene oxide adduct of a dihydric phenol with a phosphorus acid having at least one P--OH bond, an ester or a salt thereof to thereby give a precondensate, reacting said precondensate with a dihydric phenol to give an epoxy resin of a high molecular weight, and further reacting said epoxy resin with a compound having an amino group capable of reacting with an epoxy group. Said silica particles comprise a primary particle having an average particle size of 1 to 10 m.mu., a surface area of 270 m.sup.2 /g or above and a concentration of silanol groups on the particle surface of 0.25 mM/100 m.sup.2 or above.

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Tokyo, Japan

Hidehiko Kojo