SURFACE TREATMENT FOR PAINTING OF ALUMINUM ALLOY PLATE FOR FOOD CAN

摘要

PURPOSE:To increase the adhesive power of a coated film by etching an aluminum alloy plate with an alkaline soln. then cleaning the surface with rolls flocked on the outside circumference, forming a chemical conversion film on such surface and painting the surface. CONSTITUTION:The deteriorated layer by rolling of the aluminum alloy plate for a food can is etched away by the alkaline soln. The aluminum alloy plate 12 after the above-mentioned treatment is passed in the arrow A direction opposite from the rotating directions of a pair of rolls 10, 11 rotating in the opposite directions through a cleaning device 9 consisting of the rolls 10, 11 flocked with nylon hair 10a, 11a on the surface; at the same time the alkaline cleaning liquid consisting of approximately the same components as the components of the etching soln. is sprayed from a spray nozzle 15. The smut on the plate 12 is thereby effectively removed and thereafter the chemical conversion film is uniformly formed on the surface to make the formation of the coated film having the good adhesive power possible.