W. L. Gore & Associates, Inc.

Shaofeng Ran

Michael E Kennedy

Lawrence A Ford

Gregory J Shafer

Todd S Sayler

A structured fluoropolymer film including a plurality of structures having a height at least two times a thickness of a corresponding unstructured fluoropolymer film and at least a 20% increase in displacement induction period when compared to the corresponding unstructured fluoropolymer film when measured in a biaxial tensile curve at a temperature of about 125° C. In addition, the structured fluoropolymer film has a methane permeability of less than 500 μg*μm/cm/min. The structured fluoropolymer film exhibits a higher resistance to strain and retain barrier properties during manufacture and/or use.

Structured dense fluoropolymer films and methods of making same

A tetrafluoroethylene (TFE) copolymer film having a first endotherm between about 50&#xb0; C. and about 300&#xb0; C., a second endotherm between about 320&#xb0; C. and about 350&#xb0; C., and a third endotherm between about 350&#xb0; C. and about 400&#xb0; C. is provided. In exemplary embodiments, the third endotherm is approximately 380&#xb0; C. In some embodiments, the second endotherm is between about 320&#xb0; C. and about 330&#xb0; C. or between about 330&#xb0; C. and about 350&#xb0; C. TFE copolymer films have a methane permeability less than about 20 &#x3bc;g*micron/cm/min. In addition, the dense articles have a void volume of less than about 20%. Methods for dense articles from core shell tetrafluoroethylene copolymers are also provided. The dense articles exhibit improved physical and mechanical properties such as adhesion and barrier properties.

Dense articles formed tetrafluoroethylene core shell copolymers and methods of making the same

Dense articles formed from tetrafluoroethylene core shell copolymers and methods of making the same

A dense article that includes a dense TFE copolymer film is provided. The dense TFE copolymer film includes a first endotherm between about 50&#xb0; C. and about 300&#xb0; C., a second endotherm between about 320&#xb0; C. and about 350&#xb0; C., and a third endotherm between about 350&#xb0; C. and about 400&#xb0; C. To form the dense article, a core shell TFE copolymer is formed into a pellet, ram extruded into a tape, dried into a dried preform, and then stretched into a dense TFE copolymer film that exhibits improved physical and mechanical properties. The dense TFE copolymer film is produced directly from the dried preform at a deformation temperature less than about 335&#xb0; C. and without increasing the porosity of the dried preform, as would conventionally be done in expansion processes. The dense TFE copolymer films have a methane permeability less than about 20 &#x3bc;g*micron/cm/min. The dense articles have a void volume less than about 20%.

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Shaofeng Ran