SURFACE TREATED ALUMINUM MATERIAL FOR TWO-PIECE CAN AND PRODUCTION OF SURFACE TREATED ALUMINUM MATERIAL FOR TWO-PIECE CAN

摘要

PROBLEM TO BE SOLVED: To obtain a surface treated aluminum material for two-piece cans which is free of food hygienic problems and incorporation of smell without the occurrence of feather rings by forming a poreless anodically oxidized film of a specific thickness and moisture content on the surface of aluminum or its alloy and further laminating an org. resin film thereon. ;SOLUTION: The aluminum or aluminum alloy, such as Al-Mg system, is subjected to an electrolytic treatment for about 2 to 5 seconds at a bath temp. of about ≥40°C, pH about 3 to 8, current density of about 0.3 to 10 A/dm² and voltage of about 3 to 200 V in an aq. electrolyte soln. of about 2 to 150 g/l of ≥1 kinds among boric acid, borate, adipic acid, tartrate, citrate and malonate. As a result, the poreless anodically oxidized film having a thickness of 50 to 1500 Å and a moisture content of ≤5% is uniformly formed on this surface. The org. resin film of PE, polyester, etc., is laminated on this film. As a result, the surface treated aluminum material which has the excellent adhesion property of the org. resin film and obviates the occurrence of feathering at the periphery of a can tab is obtd.;COPYRIGHT: (C)1999,JPO