Nippon Paint Compnay, Ltd.

Masahiro Jo

Tamotsu Sobata

Yasutake Mino

Akio Tokuyama

Koetsu Endo

Takamasa Shimizu

Satoshi Miyamoto

Syunichi Endou

The present invention provides a surface-treating agent for a metal can, which has an effect of elevating smoothness of the metal can, shows a low foaming property and high thermal stability, but not uneasiness at safety, and thereby contributes to elevate a transferring speed of a metal can body in producing the metal can. A surface-treating agent for a metal can, comprising an emulsion containing a sorbitan fatty acid ester in a concentration of 100 to 2000 mg/l in a water medium, is sprayed to a metal can body in the final stage of a rinsing process which is carried out after a converting process.

Method for treating a metal can surface

A zinc phosphate coating film suitable for cationic electrodeposition coating and superior in both of coating film adhesion and corrosion resistance (especially, warm brine resistance and scab resistance) is formed by a conversion treatment of a metal surface using an acidic zinc-phosphating solution which does not contain a nickel ion as an essential component. The conversion treatment is carried out by bringing a metal surface into contact with a zinc-phosphating solution containing a zinc ion of 0.1 to 2.0 g/l, a phosphate ion of 5 to 40 g/l, a lanthanum compound of 0.001 to 3 g/l in terms of a lanthanum metal, and a phosphating accelerator, thereby the zinc phosphate coating film is formed on the metal surface.

Method for zinc-phosphating metal surface

A zinc phosphate film on a metal surface is used as a surface-protecting film and an under coating film for coating and so on. The zinc phosphate film is formed by treating a metal surface with an aqueous zinc phosphate solution. The aqueous zinc phosphate solution includes solutions containing a zinc ion in a concentration of more than 2 g/l to 20 g/l, a phosphate ion in a concentration of 5 g/l to 40 g/l, and at least one of silicotungstic acid and a silicotungstate in a concentration of 0.005 g/l to 20 g/l measured in terms of tungsten content.

Method for forming zinc phosphate film on metal surface

A process for phosphating the surfaces of iron-based metals, zinc-based metals or combination of such surfaces by treating the metal surfaces with an aqueous acidic zinc-phosphating solution comprising from about 0.1 to about 200 g/l of zinc ion, from about 5 to about 40 g/l of phosphate ion, from about 0.01 to 20.0 g/l as tungsten of soluble tungsten compound and a conversion coating accelerator. The metal surfaces thus phosphated with the solution are suitable for electrocoating.

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Osaka, Japan

Masahiro Jo