Macroscopically perforated porous polytetrafluoroethylene materials
AssigneeW. L. Gore & Associates, Inc.
InventorsLayne L. Moen, James T. Walter
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Abstract
A macroscopically perforated porous expanded polytetrafluoroethylene sheet material having a microstructure of nodes interconnected by fibrils wherein the perforations have a minimum diameter of about 0.1 mm and wherein the orientation of a fibril varies as a function of the proximity of a fibril to the edge of a perforation. The length of the fibrils may also vary as a function of the proximity of a fibril to the edge of a perforation. The sheet material may alternatively be provided in a tubular form.
Claims57
A macroscopically perforated porous expanded polytetrafluoroethylene sheet material comprising a sheet of porous expanded polytetrafluoroethylene having a microstructure of nodes interconnected by fibrils and having perforations through the sheet material, wherein the perforations have a mean minimum diameter of at least about 0.1 mm and wherein the orientation of a fibril varies as a function of the proximity of the fibril to the edge of a perforation.
A macroscopically perforated porous expanded polytetrafluoroethylene sheet material comprising a sheet of porous expanded PTFE having a microstructure of nodes interconnected by fibrils and having perforations through the sheet material, wherein the perforations have a mean minimum diameter of at least about 0.1 mm and wherein the length of a fibril varies as a function of the proximity of the fibril to the edge of a perforation.
A method for making macroscopically perforated porous expanded polytetrafluoroethylene material having a microstructure of nodes connected by fibrils, comprising extruding a preformed billet of a mixture of polytetrafluoroethylene and liquid lubricant to form an extrudate, forming macroscopic perforations through the extrudate, removing the liquid lubricant from the extrudate, expanding said polytetrafluoroethylene by stretching said polytetrafluoroethylene and maintaining said polytetrafluoroethylene at a temperature between about 35.degree. C. and the crystalline melt point during stretching, and heating said polytetrafluoroethylene.
A method for making macroscopically perforated porous expanded polytetrafluoroethylene material having a microstructure of nodes connected by fibrils, comprising extruding a preformed billet of a mixture of polytetrafluoroethylene and liquid lubricant to form an extrudate, removing the liquid lubricant from the extrudate, forming macroscopic perforations through the extrudate, expanding said polytetrafluoroethylene by stretching said polytetrafluoroethylene and maintaining said polytetrafluoroethylene at a temperature between about 35.degree. C. and the crystalline melt point during stretching, and heating said polytetrafluoroethylene.
Dependencies are inferred from the claim text.