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US 5,178,967 AGranted
Bilayer oxide film and process for producing same
AssigneeAlcan International Limited
InventorsAron M. Rosenfeld, Paul Smits
Life of this patent
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AssigneeAlcan International Limited
InventorsAron M. Rosenfeld, Paul Smits
Estimating the term…
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.
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:
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;
Dependencies are inferred from the claim text.