Abstract: A moisture vapor permeable, water impermeable composite sheet material is provided which is suitable for use as a housewrap material, and is also useful for other applications such as tarpaulins, or as covers for automobile, boats, patio furniture or the like. The composite sheet material includes a nonwoven substrate and an extrusion-coated polyolefin film layer overlying one surface of the substrate. The nonwoven substrate is comprised of polymeric fibers randomly disposed and bonded to one another to form a high tenacity nonwoven web. The nonwoven substrate has a grab tensile strength of at least 178 Newtons (40 pounds) in at least one of the machine direction (MD) or the cross-machine direction (CD). The extrusion coated polyolefin film layer is intimately bonded to the nonwoven substrate. The film layer has micropores formed therein to impart to the composite sheet material a moisture vapor transmission rate (MVTR) of at least 35 g/m2/24 hr. at 50% relative humidity and 23° C.

Abstract: The invention provides a sheet material comprising bicomponent filaments having first and second polymer components that are arranged in substantially distinct zones within the filaments, with the first polymer component formed of a relatively lower melting polymer and the second component formed of a relatively higher melting polymer. The filaments of the nonwoven fabric layer are densely arranged and compacted against one another to form smooth, substantially nonporous opposite outer surfaces, and the nonwoven fabric layer are calendered such that the lower melting sheath polymer is fused to the contacting surface portions of adjacent filaments to impart strength and coherency to the nonwoven fabric layer. The sheet material has excellent breathability and liquid barrier properties and may be useful in house wrap, medical garments, and envelope applications.

Abstract: Nonwoven fabric laminates suitable for use as semipermeable membrane supports are produced by forming a spunbond nonwoven fabric first layer of continuous thermoplastic polymer filaments; forming a wet-laid nonwoven fabric second layer of discrete length thermoplastic polymer fibers; and bonding the first and second layers in opposing face-to-face relationship to form a composite support, where the first and second layers define first and second outer surfaces of the composite support. The resulting semipermeable membrane supports provide an advantageous balance of properties, including smoothness, porosity, interlaminar adhesion, and flux properties.