| abstract |
A method for cleaning and modifying the surface of aluminum container sheet to make improved food can bodies and/or beverage can ends therefrom. The lowering of magnesium levels on an aluminum oxide surface and through the oxide-metal interface of this sheet, and deposition of at least some phosphorus-containing complex thereon produces container sheet that exhibits improved corrosion performance. The method comprises contacting said container sheet for less than about 20 seconds with a cleaner which preferably includes: about 1.0-10.0 wt. % (10.0-100.0 g/L) of sodium carbonate; about 0.1-2.5 wt. % (1.0-25.0 g/L) of sodium hydroxide, said cleaner including a total carbonate and hydroxide concentration in excess of about 3.0 wt. % (30.0 g/L); about 0.1-2.5 wt. % (1.0-25.0 g/L) of sodium gluconate; about 0.1-2.0 wt. % (1.0-20.0 g/L) of a compound containing 1-hydroxyethylidene-1,1-diphosphonic acid (or "HEDP"); and about 0.05-1.0 wt. % (0.5-10.0 g/L) of an alkylphenoxypolyethoxyethanol-based surfactant, the balance water and incidental impurities. |