| 摘要 |
PURPOSE: To prevent corrosion of a sheet metal by obtaining high adhesion of the sheet metal to a thermoplastic film by a method wherein a chemical conversion treated film in which at least one piece of a specific etching pit is provided, and a metallic compound is contained, is formed on its surface, and a resin film is further laminated on the chemical conversion treated film. CONSTITUTION: At least one piece of an etching pit of 1.0μm maximum width per 1μm<2> of a surface is provided. A chemical conversion treated film containing a metallic compound which contains at least one kind selected from chromium, titanium, and zirconium is formed on the surface. Further, a thermoplastic resin film is fixed by pressure onto the chemical conversion treated film to form a coated sheet. The etching pit herein is called a bearing pit by another name, which indicates a polyhedron small hole (a pit) enclosed by a low index surface generated when a metal is dissolves with a suitable etching solution or it is anode dissolved at low overvoltage, and its form depends on a structure of the metal, and a surface bearing, which is called an etching figure.
|
