Abstract: Quaternary ammonium salt having at least one alkyl group of 10 to 20 in carbon number is added to a chemical conversion solution to be at least 20 ppm in concentration, and a chemical conversion coating is formed on a surface of a metal can with this chemical conversion solution. After the chemical conversion coating is formed on the surface of the metal can with the chemical conversion solution, a surface treatment solution containing quaternary ammonium salt having at least one alkyl group of 10 to 20 in carbon number is applied to the surface of the metal can provided with the chemical conversion coating.

Abstract: The invention provides a surface-treating agent for a metal can, which diminishes friction on an outside surface of the can without giving a bad influence on attachability of paint, lacquer and the like and shows high safety to the human body. Furthermore, the invention provides a method for treating a metal can surface with said surface-treating agent. The surface-treating agent for a metal can is characterized by containing an ester compound between a polyglycerol and fatty acid(s) as an essential component. To diminish a friction coefficient of the metal can surface, the surface-treating agent is brought into contact with the metal can surface.

Abstract: 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.