Method of making an improved expanded PTFE fiber
AssigneeW. L. Gore & Associates, Inc.
InventorsBrad F. Abrams, Raymond B. Minor, Gordon L. McGregor, John W. Dolan
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Abstract
The present invention is an expanded polytetrafluoroethylene (PTFE) fiber with improved handling properties. Unlike previous expanded PTFE fibers, the fiber of the present invention employs a fiber of increased thickness so that the fiber is maintained in an unfolded orientation. The improved processing steps of the present invention create a fiber that has a number of improved properties, including more uniform dimensions along its length, improved compressibility and handling, and when woven into a fabric, the fabric is more easily processed, is of higher quality, and is more uniform.
Claims5
Process for preparing a fiber comprising a strand of expanded polytetrafluoroethylene of uniform dimensions in width along its entire length;
- wherein the fiber has an outer surface of essentially rectangular to oblong cross-section dimension, the fiber being without folds so that its outer surface is fully exposed and is essentially flat;
- and wherein the fiber in an unfolded orientation comprises cross-section dimensions with a width of between about 0.5 to 3 mm and a thickness of at least 50 mm;
- which process comprises the steps of:
- (a) providing a sheet of expanded porous polytetrafluoroethylene, which sheet has a thickness of at least 50 .mu.m;
- (b) slitting the sheet into multiple strands of fibers of at least 0.5 mm to 3 mm in width, and in which each strand of fiber has substantially uniform dimensions in width along its length;
- (c) winding the fibers onto a spool while maintaining the fiber in an unfolded, flat orientation.
Dependencies are inferred from the claim text.