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Bilayer oxide film and process for producing same

  • US 5,178,967 A
  • Filed: 02/08/1990
  • Issued: 01/12/1993
  • Est. Priority Date: 02/03/1989
  • Status: Expired due to Term
First Claim
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1. A process for producing a packaging film having low oxygen and moisture permeability including a bilayer oxide film comprising a layer containing aluminum oxide and a layer containing an oxide of tantalum or niobium, said process comprising:

  • providing a substrate comprising a metal, at least at an exposed surface of the substrate, selected from the group consisting of tantalum, niobium and anodizable alloys thereof;

    forming a coating on said surface of a material selected from the group consisting of aluminum and anodizable aluminum alloys;

    anodizing said coated substrate for a sufficient time and at a sufficient voltage to consume said coating and some of said metal of said substrate to form a bilayer oxide film, said anodization being carried out in the presence of a fluoride as an adhesion-reducing agent capable of reducing the strength of attachment of the bilayer film to the remaining metal;

    attaching a flexible packaging sheet to said bilayer film; and

    detaching said flexible sheet and said bilayer oxide film from said remaining metal.

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