Moisture vapor permeable composite sheet material and process for producing such breathable composite sheet material

摘要

In the present invention, there are described a composite sheet material comprised of at least two layers, process for producing such material and an absorbent article employing the sheet material. The composite sheet material is comprised of a thermoplastic film adhered directly to a fibrous substrate. The thermoplastic film comprises at least 50 percent by weight of a polymer material being selected from the group consisting of block copolyether esters, block copolyether amides and polyurethanes. The substrate comprises a fibrous web of at least 50 percent by weight of polyolefin polymer synthetic fibers. The composite sheet exhibits a peel strength of at least 0.1 N/cm, a dynamic fluid transmission of less than about 0.75 g/me2 when subjected to an impact energy of about 2400 joules/me2, and a moisture vapor transmission rate, according to the desiccant method, of at least 1500 g/me2/24 hours. Disclosed is also a process for preparing the above-described composite sheet material wherein the process comprises the steps of: mixing and simultaneously melting a polymer fraction mixture; melt extruding the mixed and melted stream of polymer fractions mixture through a flat film die as a molten film mixture; forcing the molten polymer film into intimate contact with the fibrous substrate while quenching the polymer mixture to form a composite sheet.