Patent ID: 10328661

Abstract:
Asymmetric expanded polytetrafluoroethylene (ePTFE) membranes that contain multiple layers of ePTFE where at least one layer of ePTFE has a microstructure different from the microstructure of a second ePTFE layer. In exemplary embodiments, the asymmetric membrane contains a first ePTFE layer that has an “open” microstructure and a second ePTFE layer that has a less open, or “tight” microstructure. A third ePTFE layer having an “open” microstructure may be positioned on the second ePTFE layer. The asymmetric membranes possess print durability and are both abrasion resistant and air permeable. Additionally, printed asymmetric ePTFE membranes demonstrate low gloss. A textile may be affixed to the asymmetric membrane such that the first ePTFE layer is the outer surface of the laminate. Laminates containing the asymmetric membrane are sufficiently durable against abrasion so that articles of apparel having an exterior film surface remain liquid proof after an abrasion challenge.