Patent ID: 7943003

Claim:
A method of forming a composite tape comprising the steps of: a. providing at least two porous expanded polytetrafluoroethylene (ePTFE) tapes, the tapes having a plurality of ePTFE layers, upper and lower layers, and side surfaces extending between upper and lower layers, b. providing at least one material capable of forming a substantially air impermeable layer, c. bonding the at least one material on at least one side surface of each of the at least two ePTFE tapes to form a substantially air impermeable layer comprising the steps of contacting and applying pressure and heat to the ePTFE tape and the at least one material above the melt temperature of the ePTFE and the at least one material, to weld the material and the ePTFE together forming a substantially air impermeable layer on the tape side surface, and d. joining at least two ePTFE tapes along side surfaces comprising the steps of 1. applying heat at a juncture of at least two ePTFE tape side surfaces having the substantially air impermeable layer bonded thereto, above the melt temperature of the substantially air impermeable layer, and 2. contacting and applying pressure to the at least two heated ePTFE tapes to weld the substantially air impermeable layers of the at least two ePTFE tapes joining the tapes to form a tape composite.