1. Field of the Invention
This invention relates to improvements in a composite paint film coating coated on a steel plate for the purpose of improving rust resistance of the steel plate and a gloss and brightness character of the coated paint film coating, and more particularly to such an improved composite paint film coating to be coated on the outer panel of an automotive vehicle.
2. Description of the Prior Art
In general, a composite paint film coating for an automotive vehicle outer panel is constituted of an electrodeposition paint film for the purpose of rust prevention, an intermediate coat paint film for the purpose of thickening the composite film coating, and a finish coat paint film for the purpose of coloring. The automotive vehicle outer panel coated with suchthus formed electrodeposition paint film, the PGD value of the finish coat paint film on a horizontal plane largely lowers, thereby degrading the commercial value of the resultant automotive vehicle.
In view of the above, it has been eagerly desired in an automotive industry to obtain a composite paint film coating exhibiting both high edge corrosion resistance and good external appearance.