of pressure by u201c adhered u201d is meant layer to layer surface contact or impregnation fully or partially of layer b into the pores of layer a as well as adherence by use of an adhesive suitable microporous polymers for layers a and c herein include fluoropolymers e g polytetrafluoroethylene or polyvinylidene fluorides polyolefins e g polyethylene or polypropylene polyamides polyesters polysulfone poly ethersulfone and combinations thereof polycarbonate polyurethanes to achieve flexibility the layers should be thin if the microporous polymer of layer c is not naturally hydrophilic it can be rendered hydrophilic by treating it materials that can be used to treat the microporous polymer to make it hydrophilic include aqueous alcoholic or aqueous alcoholic solutions of a copolymer of tetrafluoroethylene and vinylacetate polyacrylic acid and copolymers thereof polyacrylamide and copolymers thereof polyvinyl acetate pva polystyrenesulfonate polyethylene or propylene glycols peg ppg hydrophilic silicones anionic cationic nonionic or amphoteric surface active agents or mixtures and complexes of the above treatment with hydrophilic material is accomplished by applying a liquid form of the material e g a melt or solution or latex dispersion of the material as e g by dipping painting spraying roller coating or brushing the liquid on the surface application is carried out until internal surfaces of the microporous structure are coated but not until the pores are filled as that would destroy or severely lessen the water vapor transmitting property of.