BIAXIALLY ORIENTED FLUOROPOLYMER FILMS

PURPOSE: Biaxially oriented multilayer fluoropolymerfilms are provided which are useful as flat films or can be formed, such as be thermoforming, into desired shapes and are applied to medical packaging, pharmaceutical packaging, etc. CONSTITUTION: A films are produced by coextruding or laminating films having at least one layer of a fluoropolymer, at least one layer of a thermoplastic homopolymer or copolymer and an intermediate adhesive layer which is preferably a polyolefin having at least one functional moiety of an unsaturated carboxylic acid or anhydride thereof. With this structure the thermoplastic layer allows the fluoropolymer layer to be biaxially stretched many times its original length. A high orientation ratio for the fluoropolymer film increases the mechanical strength, toughness, and water vapor barrier properties of the film while using a thinner gauge fluoropolymer film. Coextrusion processing can be done at higher temperatures, i.e. in the range of from at about 280°C to about 400°C. These temperatures allow films to be produced in the absence of polymer degradation and film melt fracture.