Abstract: A surface treatment agent composition for non-chromium steel sheets for removing iron ions without reducing the amount of aluminum ions when subjecting the steel sheet to surface treatment by means of cathodic electrolysis using a surface treatment agent containing aluminum ions as the main component; and a method for producing a surface-treated steel sheet using the composition. A surface-treated steel sheet exhibiting high corrosion resistance, a surface-treated steel sheet with an organic coating, and a can lid, can body and seamless can produced using the surface-treated steel sheets. A surface treatment agent composition for steel sheets contains aluminum ions, fluorine ions and polycarboxylic acid and is used as the surface treatment bath used for forming a surface treatment coating film on the surface of the steel sheet by cathodic electrolysis.

Abstract: To provide a bath for surface treatment capable of forming a surface-treating film having excellent corrosion resistance by a high-speed electrolytic treatment, and a method of producing a surface-treated steel plate having excellent corrosion resistance and closely adhering property to the coating maintaining good productivity. A bath for surface treatment used for forming a surface-treating film on the surface of a steel plate by cathodic electrolysis, the bath for surface treatment containing Zr and/or Ti, and a polycarboxylic acid.

Abstract: A surface-treated steel plate obtained by forming, on at least one surface of the steel plate by cathodic electrolysis, a surface-treating film which contains a mixed oxide of an oxide of Fe and at least one of an oxide of Zr or an oxide of Ti, and a polycarboxylic acid, the amount of Zr or Ti, or the total amount of Zr and Ti if both of them are present, being from 3 to 300 mg/m2 and the amount of C being from 0.1 to 5.0 mg/m2.

Abstract: [Problems] To provide a bath for surface treatment capable of forming a surface-treating film having excellent corrosion resistance by a high-speed electrolytic treatment, and a method of producing a surface-treated steel plate having excellent corrosion resistance and closely adhering property to the coating maintaining good productivity. [Means for Solution] A bath for surface treatment used for forming a surface-treating film on the surface of a steel plate by cathodic electrolysis, the bath for surface treatment containing Zr and/or Ti, and a polycarboxylic acid.

Abstract: A connection method and connection apparatus for connecting long belt-shaped non-oriented resin films that are continuously advanced. A leading resin film and a trailing resin film can be connected while processing in a following step is continuously performed. The tip end of a trailing resin film (22) is joined and connected to a leading resin film {11), and then a portion, immediately after the connected position, of the leading resin film is heated to a predetermined temperature range and cut.