Textured, porous, expanded PTFE
AssigneeImpra, Inc.
InventorsRajagopal R. Kowligi, John M. Bibeau, Howard H. Taylor
Life of this patent
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Abstract
A more porous PTFE is obtained by impressing a pattern into extruded PTFE and then expanding the PTFE. The pattern can be impressed by knurling or, preferably, by rolling the sheet between rollers having a pseudo-random pattern formed on the surface of the roller. The uniformity of the pores is controlled by the pattern; viz. a coarse pattern produces a wider distribution of internodal distances than a finer pattern.
Claims14
An expanded polytetrafluoroethylene sheet produced by the process of extruding a mixture of polytetrafluoroethylene and a lubricant into a sheet;
- forming a pattern of defect sites in said sheet by one of impressing an external pattern into said sheet;
- high energy bombardment with solids, etching, laser irradiation and actinic irradiation;
- expanding said sheet;
- and sintering said sheet, whereby the expanded polytetrafluoroethylene sheet is characterized by having internodal distances non-uniformly distributed across the range of 10-200 microns.
An expanded polytetrafluoroethylene material produced by the process of extruding a mixture of polytetrafluoroethylene and a lubricant into a predetermined shape;
- forming at least one region of non-uniformly distributed nodes and fibrils in said shape, said nodes and fibrils having internodal distances non-uniformly distributed across the range of 10-50 microns, by one of impressing an external texturing pattern into said sheet, high energy bombardment with solids, etching, laser irradiation and actinic irradiation;
- expanding said shape;
- and sintering said shape.
Dependencies are inferred from the claim text.