PROCESS FOR PRODUCTION OF STEEL SHEET FOR CONTAINER MATERIAL WHICH HAS REDUCED LOAD ON ENVIRONMENTS, STEEL SHEET FOR CONTAINER MATERIAL WHICH HAS REDUCED LOAD ON ENVIRONMENTS, AND LAMINATE STEEL SHEET FOR CONTAINER MATERIAL AND COATED PRECOAT STEEL SHEET FOR CONTAINER MATERIAL WHICH ARE PRODUCED USING THE STEEL SHEET

摘要

Disclosed is a method for the cathodic electrocoating of a tin-coated steel sheet in a treatment solution that does not contain any Cr compound, F or nitrite nitrogen. In the method, a tin oxide layer that is not subjected to a cathodic electrocoating treatment yet and is arranged on a tin-coated steel sheet is thinned to a specified thickness or less by a cathodic electrocoating treatment in an aqueous solution containing sodium carbonate or sodium hydrogen carbonate or a aqueous sulfuric acid solution immersion treatment, and the tin oxide layer is subjected to a cathodic electrocoating treatment in an aqueous solution of an alkaline metal sulfate containing a zirconium compound having a specified composition. In this manner, a coating film is formed on the tin oxide layer at a specific adhered amount in terms of Zr content. Also disclosed are: a process for producing a chromium-free steel sheet for a container material, which has excellent adhesion to an organic resin film and excellent iron elution resistance after dent impact; and a steel sheet for a container material, which is produced by the process.