Kansai Paint Company, Ltd.

Masayuki Misawa

Masafumi Kume

Yasuyuki Hirata

Masahiko Sagane

Toshio Ogasawara

Hidetaka Yago

A method of electrodeposition coating, which comprises performing a first electrodeposition coating on an article as a cathode using (I) a cationic electrodeposition paint comprising (A) a resin and (B) at least one pigment, said pigment (B) containing at least 5% by weight of a pigment having an oil absorption of at least 100 and being incorporated so that the total oil absorption of the pigment (B) is in the range of 1,000 to 10,000 per 100 g of the resin (A), then while the resulting coated film is in the uncured state, performing a second electrodeposition coating on it using (II) an emulsion-type cationic electrodeposition coating paint comprising a resin (C) and a pigment (D) and having a minimum electrodeposition current density of not more than 0.7 mA/cm.sup.2 and a degree of emulsification of at least 80% by weight, said pigment (D) having a lower total oil absorption than the total oil absorption of the pigment (B) in the cationic electrodeposition paint (I), and thereafter curing the applied films under heat to form a composite cured coated film.

Electrodeposition coating method

In an electrophoretic coating process with use of a cationic electrophoretic coating composition having its pH adjusted to 6 to 8, the cationic electrophoretic coating composition is replenished with a replenishing coating agent having a lower neutrality than the cationic electrophoretic coating composition to adjust the pH value and solids concentration of the composition, by admixing the replenishing coating agent with a portion of the cationic electrophoretic coating composition being used for the coating process to prepare a replenishing composition and adding the replenishing composition to the cationic electrophoretic coating composition.

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Hiratsuka, Japan

Masayuki Misawa