A method for making a thin walled ePTFE tube having improved axial and radial strength includes the steps of: providing an unsintered or partially sintered ePTFE membrane; wrapping the ePTFE membrane around a mandrel or form tool to form an ePTFE tube; matting the ePTFE tube; immediately thereafter, sintering the matted ePTFE tube; removing the sintered ePTFE tube from the mandrel or form tool; stretching the sintered ePTFE tube in the axial direction; stretching the ePTFE tube in the radial direction over a second mandrel that is greater in diameter than the reduced axially stretched diameter, but less than the first mandrel diameter; overwrapping the second mandrel with a second ePTFE membrane; matting the ePTFE tube; immediately thereafter, sintering the matted ePTFE tube; and removing the sintered ePTFE tube from the second mandrel or form tool.
Issued U.S. Patent No. 8,609,249
matgrell2019-10-01T22:12:38+00:00