Nihon Parkerizing Co., Ltd.

Amane Suzuki

Tomohiro Iko

Hidekazu Fukushi

The present invention addresses the problem of providing, a metal surface treatment agent capable of exhibiting excellent corrosion resistance and excellent coating adhesion in painted metal materials; and a metal surface treatment method using the metal surface treatment agent. The problem is solved by a pretreatment agent that is used in a pretreatment of a chemical conversion treatment performed for forming a chemical conversion coating on/over a surface of a metal material, the pretreatment agent containing: a metal alkoxide (A) containing at least one metal element selected from zirconium, titanium, vanadium, and aluminum; and at least one sulfonic acid (B) selected from methanesulfonic acid, ethanesulfonic acid, hydroxymethanesulfonic acid, and hydroxyethanesulfonic acid. The problem is also solved by a chemical conversion treatment agent that contains a zirconium alkoxide (a) and a zirconium-containing ion supply source (b), and has a pH of 1.5 to 6.5.

Pretreatment agent and chemical conversion treatment agent

The present invention addresses a problem of providing, for example, a metal surface treatment agent capable of forming a coating film that exhibits good corrosion resistance at edges, such as cut portions, of a coated metal material. The problem is solved by a metal surface treatment agent comprising: an ion (A) containing at least one kind of metal selected from zirconium, titanium and hafnium at a metal-equivalent molar concentration of 0.1 mmol/L or higher; and an aqueous urethane resin (B) having a weight-average molecular weight of 50,000 or higher at a solid mass concentration of 0.5 to 10 g/L, in which the ratio of a solid mass (B) of the resin (B) to a metal-equivalent mass (A) of the ion (A), [B/A], is 0.7 or higher.

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Tokyo, Japan

Amane Suzuki