| 摘要 |
The pretreatment agent for use before forming a coat by paint application of the present invention contains (A) one or more metal elements selected from a group consisting of zirconium, titanium and hafnium, (B) fluorine, (C) one or more coupling agents selected from an amino group-containing silane coupling agent, its hydrolyzate, and its polymer, and (D) a component of at least one of an allylamine and a polyallylamine, in which the ratio by mass of the coupling agent (C) to the component (D), (C/D) is 1 or more. The coating method by paint application of the present invention includes a chemical conversion treatment step of chemically treating a metal substrate with the pretreatment agent, and a step of forming a coat by paint application on the chemically-treated metal substrate. When a coating film is formed through forming a coat by paint application on the surface of a metal substrate that has been pretreated according to the present invention, the coating film can have excellent adhesion, salt water resistance and impact resistance. |
