CURABLE AUTODEPOSITION COATING FILM, AUTODEPOSITION COMPOSITION, COATED METAL SUBSTRATE, AND METHOD FOR FORMING COATING FILM ON METAL SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To obtain an autodeposition coating material composition and to provide a method for forming a coating film on a metal substrate through the autodeposition of the coating material composition.;SOLUTION: An autodeposition composition for forming a polymer coating film having reduced gloss is produced by using a resin bearing at least one hydroxy group and at least one epoxy group in one molecule, a low-temperature crosslinking agent and a high-temperature crosslinking agent. The resin and the low-temperature crosslinking agent are used to form a reactive prepolymer, which is mixed or emulsified with the high-temperature crosslinking agent thereby the autodeposition composition is prepared. In another method, a hybrid crosslinking agent bearing free isocyanate group that is reactive with the above resin at a relatively low temperature and bearing at least one functional group that is only reactive with the resin at a relatively raised temperature can be used for the formation of the autodeposition composition. The polymer coating film formed by autodeposition on the metal substrate is matte-finished with high resistance to surface defects.;COPYRIGHT: (C)2003,JPO