PURPOSE: To provide a water paint coating compsn for chromate-treated galvanized steel sheets, which has excellent resistance to water and corrosion, adhesion, etc., by mixing a water-dispersible amino resin with an org. amine salt of an oil-free alkyd resin contg. tannic acid as a component.
CONSTITUTION: A polyhydric alcohol, 1W20wt% tannic acid, a polycarboxylic acid such as phthalic acid and, if necessary, a monocarboxylic acid are subjected to an esterification reaction to prepare an oil-free alkyd resin having an acid value of 20W100KOHmg/g and a hydroxyl value of 50W250KOHmg/g, which is then neutralized with a neutralizing agent such as diethylamine or ammonia to obtain an org. amine salt or ammonium salt. 50W95wt% org. amine salt or ammonium salt of said alkyd resin is mixed with 50W5wt% water-dispersible or water-soluble amino resin to obtain the desired water paint coating compsn.
SASAKI HIROJI
HIGUCHI YOSHIHIRO
| JPS5226534A | 1977-02-28 |