Nippon Paint Compnay, Ltd.

Amchem Products, Inc.

Ryoichi Murakami

Minoru Ishida

Shoji Oka

Hideo Shimizu

Takashi Yoshii

Akiko Sueyoshi

Hiroto Yonekura

Mitsuo Yamada

Kanji Nishijima

Toshihiro Okai

Yoshio Kojima

Makoto Ando

Hirotaka Kanato

Syuzi Sato

Tetsuo Yanagihara

Yoshiyuki Uyeda

Masahiro Zinnouti

Yukio Anegawa

Keizi Masada

Cathodic electrodeposition paints of the type in which a cationically modified epoxy resin is crosslinked with a blocked polyisocyanate crosslinker are disclosed. The paint contains a cationically modified epoxy resin having at least one oxazolidone ring in the molecule and a Tg ranging between 0.degree. C. and 35.degree. C., and a blocked alicyclic polyisocyanate. The use of lead based anticorrosive pigments may be eliminated or substantially reduced. When the alicyclic polyisocyanate is a bicycloalkane polyisocyanate, the use of organic solvent may also be reduced.

Cathodic electrodeposition paint

A method for cationic electrocoating which comprises electrocoating a substrate in an electrocoating composition comprising an electrocoating resin having a reactive group admixed with a paste comprising a chromate pigment in a water-insoluble or hardly soluble, reactive group-containing organic binder and said paste having a water content of not more than 2% by weight and said composition having a concentration of 200 to 5,000 ppm in terms of CrO.sub.3, the reactive group in the electrocoating resin being crosslinkable with the reactive group in the organic binder. The formed electrocoating film has high rust prevention.

Rust preventive cationic electrocoating

A process for phosphating a metal surface to be electrocoated, which comprises treating the metal surface with an acidic phosphating solution comprising a zinc compound in a concentration of 0.5 to 1.5 g/l as zinc ion, a phosphate in a concentration of 5 to 30 g/l as phosphate ion and a nitrite in a concentration of 0.01 to 0.2 g/l as nitrite ion and/or an aromatic nitro compound in a concentration of 0.05 to 2 g/l in water at a temperature of 40 to 70.degree. C. first by dipping for not less than 15 seconds and then by spraying for not less than 2 seconds.

Phosphating process of metal surface

A dip phosphating process, which comprises introducing a substrate to be phosphated into a phosphating bath while undulating the phosphating solution at the entrance section of the bath.

Dip phosphating process

A process for iron phosphating the surface of an iron substrate which comprises treating said surface with a phosphating solution comprising at least one of alkali metal and ammonium phosphates and at least one of aromatic nitro compounds as a phosphating accelerator in an aqueous medium and having a pH of about 3 to 6.5 in a closed system phosphating installation.

Process of phosphating an iron substrate in a closed system using

In a method for phosphating the surface of a metallic substrate by treatment with a phosphating solution containing nitrite ions as the accelerator, an improvement wherein the supply of the nitrite ions to the phosphating solution is carried out by electrolytic reduction of nitrate ions present in the phosphating solution while changing the direction of the current flow at a fixed interval of time, whereby a desired concentration of nitrite ions in the phosphating solution is maintained without accumulation of alkali metal and/or ammonium ions unavailable for the phosphating and also without accumulation of precipitates on the electrode, and a uniform phosphate coating film having satisfactorily good coating properties is formed on said surface.

Phosphating of metallic substrate

A process for phosphate conversion coating iron and steel which includes a multi-step water rinsing stage after the conversion coating stage, which comprises subjecting a part of the rinsing water used therein to a reverse osmosis treatment, returning the concentrated liquid thereof to the conversion coating stage, and using the filtrate as replenishing water for the conversion coating and/or the degreasing and water rinsing stages after subjecting it to an ion exchange treatment.

Process for phosphate conversion coating with treatment of rinse water

In a method for phosphating the surface of a metallic substrate by treament with a phosphating solution comprising nitrite ions as the accelerator, an improvement wherein the supply of the nitrite ions to the phosphating solution is carried out by electrolytic reduction of nitrate ions present in the phosphating solution, whereby a desired concentration of nitrite ions in the phosphating solution is maintained without accumulation of alkali metal and/or ammonium ions unavailable for the phosphating and a uniform phosphate coating film having satisfactorily good coating properties is formed on said surface.

Phosphating of metallic substrate with electrolytic reduction of nitrate

A phosphate coating solution for forming coatings on a metal surface is contacted with an anion-exchanger loaded or contacted with nitrite ions, whereby the nitrate ions present in the coating solution are replaced by the nitrite ions. This process permits continued operation of a phosphate coating process without replenishing a nitrite solution. This process also allows no accumulation of alkali metal and/or ammonium ions unavailable for the phosphate coating and provides uniform coatings with satisfactory coating properties on the metal surface.

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Kyoto, Japan

Ryoichi Murakami