DOUBLE-LAYERED COATING FILM FORMATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a coating film formation method by which a double-layer coating film having excellent rust preventing properties can be obtained using a two wet coating method where water base intermediate coat is applied to the surface of an un-cured electrodeposition coating film and both are cured under heating at once without causing mixing of both the layers, and to provide a multi-layer coating film formation method by which a multi-layer coating film having excellent chipping resistance, appearance and yellowing resistance can be obtained by applying overcoat base coat and clear coat to the surface of the obtained double-layer cured coating film in a wet system and thereafter performing the 2nd baking. SOLUTION: The double-layered coating film formation method comprises: a stage (I) where electrodeposition coating is performed to the surface of an electrically conductive base material to form an un-cured electrodeposition coating film; and a stage (II) where the surface of the electrodeposition coating film is coated with water base intermediate coat and thereafter the un-cured electrodeposition coating film and the intermediate coating film are simultaneously cured under heating. In the electrodeposition/intermediate double-layer coating film, the solubility parameters of binder resin and a curing agent being the constituents of both layers are controlled to ranges satisfying specified relational inequalities. COPYRIGHT: (C)2005,JPO&NCIPI