Nissan Motor Company Limited

Takeshi Nomoto

Takeshi Aiba

Masatoshi Tanaka

Masahiro Takegawa

Fumiaki Nakao

An object of the present invention is to provide an electrodeposition paint composition and a method of forming an electrodeposited coating, which exhibit quality of coating deposition even in the interior of narrow spaces of objects subjected to painting. A solution of the object is cationic electrodeposition paint composition in which in an aqueous medium contained are a cationic epoxy resin, a blocked isocyanate curing agent, a hydrophobic agent wherein an SP value of the hydrophobic agent (C) is 10.2 or more and less than 10.6 and is lower by 0.6 to 1.0 than an SP value of the cationic epoxy resin, a viscosity modifier, and a neutralizing acid, and in which coulombic efficiency of the cationic electrodeposition paint composition is 2.0 to 2.5 mg/(&#x3bc;m&#xb7;C). A voltage boost rate of the voltage in painting is 30 to 70V/10 seconds.

Cationic electrodeposition paint composition paintable even on narrow-clearance portion, and electrodeposition coating film using the same

A cationic electrodeposition coating is provided having excellent covering power (clearance application properties), edge anticorrosion properties, and finish properties. The cationic electrodeposition coating composition comprises a specific amino-group-containing epoxy resin; blocked polyisocyanate obtained by reacting an active hydrogen-containing component containing propylene glycol, and a polyisocyanate compound; and 0.1-20 mass parts of a cationic electrodepositing gelled microparticulate polymer obtained by crosslinking an acrylic copolymer containing hydrolyzable alkoxysilane groups and cationic groups, per a total of 100 mass parts of the solids fraction of the amino-group-containing epoxy resin and the blocked polyisocyanate compound.

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Atsugi, Japan

Takeshi Nomoto