Aluminum Company of America

Donald L Nock

Daniel L Serafin

Robert E Bombalski

Frank A Mozelewski

Romeo C Pascasio

George T Gregory

A shaped strip of highly reflective aluminum protected by an anodic oxide coating and a light-permeable fluoropolymer coating which is non-adhesively interstitially mechanically bonded to the microscopic irregularities of the anodic oxide surface. There is no adhesive used to obtain chain entanglement. The highly reflective strip may be substituted for polished stainless steel and/or bi-metal and used under comparably aggressive conditions for a prolonged period without deleteriously affecting the initial D/I (distinctness of reflected image) of the shaped strip. The strip of arbitrary length is shaped in rolling dies so that at least a portion of the strip has a radius of less than 10 mm without damaging or separating the fluoropolymer coating. The specific steps of the claimed process require starting with a clean strip which is brightened to a nearmirror-like finish, then treated to carry a thin porous aluminum oxide coating in a phosphoric acid bath under direct current (DC). After rinsing and drying, the reflective surface is coated with the fluoropolymer while maintaining at least 80% D/I. The strip, now dual-coated, is then formed to a desired profile. The dual-coated strip, in turn, may be treated with a corona discharge to activate its surface so as to non-adhesively bond an adhesive chosen to bond a thermoplastic strip of synthetic resin to the activated fluoropolymer surface.

Method of making a shaped reflective aluminum strip, doubly-protected

An aluminum-magnesium alloy sheet product having improved levels of brightness for use as container stock including food containers and beverage container ends, said sheet product chemically treated with an alkaline-based cleaner containing a sufficient amount of a compound of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) to inhibit the formation of a magnesium oxide-containing film thereon. Preferably, the sheet product is cast from a 5000 Series aluminum alloy (Aluminum Association designation) and the cleaner contains between about 0.2-0.7% by weight of the HEDP compound. A method for improving the brightness levels of an aluminum-magnesium alloy sheet product is further disclosed. The method comprises chemically treating the sheet product with an alkaline-based cleaner containing between about 0.2-0.7% by weight of an HEDP compound to inhibit the formation of a magnesium oxide-containing film thereon.

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New Kensington, PA, United States of America

Donald L Nock