W. L. Gore & Associates, Inc.

Lawrence A Ford

Gregory J Shafer

Michael E Kennedy

Shaofeng Ran

Todd S Sayler

Edward H Cully

Alexander Zaggl

An additive manufacturing process is provided to produce integral 3-dimensional (3D) articles by laminating together a plurality of expanded polytetrafluoroethylene (ePTFE) membranes. The process includes repetitive cycles of ePTFE membrane lamination paired with laser cutting/bonding to produce a desired geometry based on a predefined pattern. The process may be practiced manually or may be configured to work with commercially available LOM machines/systems developed for use with other roll-to-roll processible materials, such as paper.

Process for forming porous three dimensional expanded polytetrafluoroethylene articles

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%.

A true tetrafluoroethylene (TFE) copolymer of the fine powder type is provided, wherein the copolymer contains polymerized comonomer units of at least one comonomer other than TFE in concentrations of at least or exceeding 1.0 weight percent, and which can exceed 5.0 weight percent, wherein the copolymer is expandable, that is, the copolymer may be expanded to produce strong, useful, expanded TFE copolymeric articles having a microstructure of nodes interconnected by fibrils. Articles made from the expandable copolymer may include tapes, membranes, films, fibers, and are suitable in a variety of end applications, including medical devices.

Expandable TFE copolymers, method of making, porous, expanded article thereof

Expandable TFE copolymers, method of making, and porous, expanded articles thereof

Expandable TFE copolymers, methods of making, and porous, expanded articles thereof

Expanded TFE copolymers, method of making and porous, expanded articles thereof

A process for the polymerization of a true tetrafluoroethylene (TFE) copolymer of the fine powder type is provided, wherein the copolymer contains polymerized comonomer units of at least one comonomer other than TFE in concentrations of at least or exceeding 1.0 weight percent, and which can exceed 5.0 weight percent, wherein the copolymer is expandable, that is, the copolymer may be expanded to produce strong, useful, expanded TFE copolymeric articles having a microstructure of nodes interconnected by fibrils.

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Munich, Germany

Lawrence A Ford