Water-resistant water vapour-permeable oleophobic microporous polymer film

摘要

A flexible, liquid water resistant, water vapour-permeable oleophobic composite comprises a layer of water vapour-permeable, oleophobic, liquid water resistant microporous polymer film (I) adhered to an air-impermeable, water vapour-permeable polymer layer (II). (I) is expanded PTFE treated with an oleophobic fluorocarbon and has an oil rating of at least 2, preferably at least 8. (II) is a polyurethane. (II) is adhered to a further layer (III) which is water vapour-permeable and liquid water resistant and optionally oleophobic. (III) is expanded PTFE treated with an oleophobic fluorocarbon. A textile layer can be laminated to one or both sides of the composite. PREFERRED PROCESS - (I) can be laminated to (II), or (II) can be laminated to a microporous polymer film that is water vapour-permeable and liquid water resistant and the composite treated with an oleophobic material.