Bilayer oxide film and process for producing same
First Claim
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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Accused Products
Abstract
A bilayer oxide film which comprises a preferably porous layer containing aluminum oxide and a non-porous layer comprising an oxide of a valve metal, e.g. tantalum. The layers are integral. The film is produced by forming a coating of aluminium or an anodizable aluminum alloy on a valve metal (or alloy), anodizing the resulting structure in an electrolyte (preferably one capable of converting the aluminum (or alloy) to a porous oxide film) in the presence of an adhesion-reducing agent (e.g. fluoride ions) that makes the resulting anodized bilayer film easily detachable from the remaining valve metal. The bilayer film is then detached from the valve metal, e.g. by adhering a flexible plastic film to the bilayer and using the film to peel off the bilayer from the valve metal. The resulting bilayer can be used for a variety of purposes, e.g. as a vapor or oxygen barrier useful for packaging, or as a coating containing magnetic particles used to make a magnetic recording medium.
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Citations
31 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A packaging film of low oxygen and moisture permeability including a bilayer oxide film comprising a layer of aluminum oxide and a layer of an oxide of a metal selected from the group consisting of Ta, Nb and anodizable alloys thereof, said layers being integral;
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said packaging film having been produced by a process which comprises; 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. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31)
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Specification