Reflective aluminum strip, protected with fluoropolymer coating and a laminate of the strip with a thermoplastic polymer

A process for converting a sheet of aluminum alloy in the range from about 0.010" (inch) (0.25 mm) to about 0.050" (1.25 mm) thick, into a decorative reflective sheet, protected with a combination of a conversion coating and cured fluoropolymer coating, said protected sheet having a surface substantially free of degradation due to environmental exposure, said process comprising:

• (a) providing a bright rolled aluminum alloy sheet having a D/I of at least 85% and a 2.degree. diffuseness no greater than 1.00;
• (b) cleaning at least one surface of said sheet of aluminum alloy to remove superficial contaminants and leave a clean surface;
• (c) chrome conversion coating said clean surface in a conversion coating both in a temperature range of from 60.degree. F. to 100.degree. F. to generate said clean surface a tightly adherent film of a metal compound in the range of from 3 to 20 mg/ft.sup.2 and a thickness less than about 4000.ANG.;
• (d) rinsing said conversion coated surface and drying, to leave a dry reflective surface;
• (e) contacting said dry reflective surface with a fluoropolymer in an amount such that, upon curing, a cured fluoropolymer is interstitially mechanically bonded to said conversion coating, so as to form said reflective sheet coated on at least one side which maintains at least 80% D/I;
• and
• (f) shaping said coated sheet to conform to a profile having at least one radius which is less than 10 mm without debonding said cured matrix fluoropolymer from said conversion coating at the interface thereof.

In a process for making a decorative laminate of shaped reflective aluminum strip having a D/I of at least 80% which strip is protected first with a conversion coating, then with a coating of organic polymer, and followed with a coating consisting essentially of an organic thermoplastic synthetic resinous strip adhesively laminated to said organic polymer, the improvement comprising,

• (a) generating on a surface of said reflective strip, a chrome conversion coating in a density range of from 3 to 20 mg/ft.sup.2 and a thickness less than about 4000.ANG.;
• (b) rinsing said conversion coated surface in water and drying,
• (c) contacting said conversion coated surface with a dilute solution of a light-permeable fluoropolymer in an inert organic solvent, said fluoropolymer being present in an amount such that, upon curing, a cured matrix fluoropolymer is interstitially mechanically bonded to said conversion coating, without substantially sacrificing the reflected image clarity and other optical properties of said reflective surface of said aluminum alloy having a D/I of at least 80%,
• (d) shaping said dual-coated strip to conform to a profile having at least one radius which is less than 10 mm without debonding said cured matrix fluoropolymer from the conversion coating at their interface,
• (e) treating a selected portion in the range from 0 to 100% of said fluoropolymer's exterior surface, with a corona discharge sufficiently to produce an activated fluoropolymer surface able to interstitially non-adhesively bond an organic adhesive, to which adhesive, in turn, said strip of thermoplastic polymer is adhesively bondable,
• (f) coating said selected portion of said activated surface with said organic adhesive while maintaining the remaining portion bare and reflective, and
• (g) contacting said organic thermoplastic synthetic resinous strip with said organic adhesive under sufficient pressure to form a coherent bond between said thermoplastic strip and said fluoropolymer coating, whereby said bare and reflective portion of said fluoropolymer's surface has a D/I which is essentially undiminished, and said strip retains substantially mirror-like characteristics after being subjected to degradation due to prolonged environmental exposure.