Aqueous primer coating composition, process for formation of coating film using said composition, and coated article

摘要

The present invention provides: an aqueous primer coating composition, which can form a coating film excellent in the humidity-resisting adhesion and the gasohol resistance, and which can enhance the productivity in the coating steps; a process for formation of a coating film using this composition; and a coated article. The aqueous primer coating composition comprises an acid-anhydride-modified chlorinated polyolefin emulsion resin (A), an aqueous urethane dispersion (B), an aqueous epoxy resin (C), and an organic strong base and/or its salt (D); wherein: relative to the total nonvolatile content of the (A), (B), and (C), the nonvolatile content of the (A) is in the range of 20 to 60 weight %, that of the (B) is in the range of 10 to 40 weight %, and that of the (C) is in the range of 20 to 60 weight %, and further, the (D) is in the range of 1 to 5 weight %. The process for formation of a coating film comprises the steps of: coating a substrate with this aqueous primer coating composition; and thereafter drying the resultant primer coating film in such a manner that its nonvolatile content will not be less than 60 weight %; and thereafter overcoating the primer coating film with a base paint and a clear paint; and thereafter baking the resultant three-layered coating film onto the substrate.