HIGHLY ORIENTED FLUOROPOLYMER FILMS

摘要

The present invention provides highly oriented multilayer films. They are produced by coextruding or laminating films having at least one layer of a fluoropolymer, at least one layer of a polyolefin homopolymer or copolymer and an intermediate adhesive layer of a polyolefin having at least one functional moiety of an unsaturated carboxylic acid or anhydride thereof. With this structure the polyolefin layer allows the fluoropolymer layer to be stretched up to ten times its original length. Such 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 DEG C to about 400 DEG C. These temperatures allow films to be produced in the absence of polymer degradation and film melt fracture.