To provide a water paint composition forming a coating film having excellent anticorrosion, waterproof property, and the like, and a coating method using the composition.
The water paint composition is disclosed that contains: (I) an aqueous resin dispersion containing a modified starch, including dispersant resin particles with an average particle size of 1,000 nm or less containing a (co)polymer of (a) the modified starch and (b) a polymerizable unsaturated monomer (m1) as a constituent; (II) a phosphoric acid-based rust preventive-pigment; and (III) a nitrogen-containing compound; wherein, based on 100 pts.mass of a solid content of the component (I), a content of the component (II) is 5-60 pts.mass and a content of the component (III) is 1-20 pts.mass. The coating method is also disclosed for coating the water paint composition on the surface of a metal substrate or an existing coated surface of a metal substrate.
SAIGA TADANOBU
MAKINO KENICHI
SHIGEYA JUN
