METHOD FOR FORMING MULTILAYER FILM

摘要

The present invention addresses the problem of providing: a method for forming a multilayer film that exhibits excellent finishing properties and corrosion resistance without affecting electrodeposition coatability even if part or all of a washing step is omitted after a chemical conversion treatment; and a coated article. The present invention provides a method for forming a multilayer film that comprises the following steps for forming a chemical conversion treatment film and an electrodeposition coating film on a metal object to be coated: a step (1) in which the metal object to be coated is immersed in a chemical conversion treatment liquid in order to form the chemical conversion treatment film; and a step (2) in which a part or all of a washing step is omitted and a cationic electrodeposition paint is used to perform electrodeposition coating of the metal object to be coated in order to form the electrodeposition coating film. The method for forming a multilayer film is characterized in that, when the total amount of resin solids is used as a reference, the cationic electrodeposition paint contains 40-88 mass% of an amino group-containing epoxy resin (A), 10-50 mass% of a blocked polyisocyanate (B), and 2-40 mass% of a pigment dispersion resin (C), and the quaternary ammonium salt concentration in the cationic electrodeposition paint is 0.03 mmol/g or less per resin solid content in the paint.