Back to results
US 4,902,423 AGranted
Highly air permeable expanded polytetrafluoroethylene membranes and process for making them
AssigneeW. L. Gore & Associates, Inc.
InventorJohn E. Bacino
Life of this patent
Estimating the term…
Abstract
A thin, low density porous polytetrafluoroethylene membrane having very large pores and heretofore unknown high air permeabilities is described. The membrane is produced by a particular series of longitudinal and transverse stretching steps carried out under particular conditions.
Claims7
A thin, low density, porous polytetrafluoroethylene membrane having an open structure defined by small nodes interconnected with fibrils, said membrane characterized by having a porosity equal to or greater than 90%, a density of 0.2 g/cc or less, and permeabilities to air between Frazier numbers of 100 and 350.
Dependencies are inferred from the claim text.