Kansai Paint Company, Ltd.

Nissan Motor Company Limited

Yoichi Masubuchi

Eisaku Nakatani

Akira Tominaga

Masafumi Kume

Haruo Nagaoka

Tadashi Watanabe

Tadayoshi Hiraki

Tsuneo Sakauchi

Katsuya Yamamoto

Hitoshi Kimura

Hiroyuki Kishi

Yoshinobu Tamura

Masahide Nagaoka

A composite paint film formed on a steel sheet of an automotive vehicle body. The composite paint film comprises an electrodeposition paint film (I) coated on the steel sheet, and an intermediate coat paint film (II) coated on the first paint film. The electrodeposition paint film is formed of an epoxy-based cationic electrodeposition paint composition and has a minimum melt viscosity not less than 0.2 during hardening. The epoxy-based cationic electrodeposition paint composition includes an amine-added epoxy resin (1) of the type which may be hardened with a blocked isocyanate, a colloidal silica-containing gelled particulate (2), and an alkyltin ester compound of a liquid aliphatic carboxylic acid. The above-mentioned colloidal silica-containing gelled particulate is formed by dispersing a mixture of an acrylic copolymer having a hydrolizable alkoxysilane group and a cationic group and a cationic acidic colloidal silica in water to carry out a cross-linking reaction in particles of the colloidal silica. The second paint film (II) has a hardening starting time ranging from 15 to 20 minutes.

Composite paint film

A cationic electrodeposition coating composition for forming a multilayer film, said composition comprising

Cationic electrodeposition coating composition for multilayer film

A process for forming a composite coated film, which comprises coating a cationically electrodepositing paint composed mainly of a cationic resin having a functional group capable of reacting with isocyanate groups on the surface of a substrate, then coating an organic solvent-base paint containing a polyisocyanate compound and capable of forming a coated film having a static glass transition temperature of 0.degree. to -75.degree. C. on the surface of the electrodeposited paint film, and then coating a top coat paint.

Process for forming composite coated film

This invention provides a coating method comprising the steps of applying to an electroconductive substrate a cationic electrophoretic primer which contains a binder resin having in its molecule a functional group capable of reacting with an isocyanate group under a curing condition to form a primer coat, applying to the primer coat a surfacer or topcoating containing a hydroxyl-containing resin and polyisocyanate compound to form a surfacer coat or topcoat and curing the two coats at the same time at a temperature between room temperature and about 130.degree. C.

Multiple coating method

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Hiratsuka, Japan

Yoichi Masubuchi