BREATHABLE COMPOSITE SHEET STRUCTURE

摘要

A moisture vapor permeable, substantially liquid impermeable composite sheet material (10) comprising a fibrous substrate (14, 16) and a moisture vapor permeable thermoplastic film layer (12). The moisture vapor permeable film has an average thickness of less than 25 microns, a peel strength of at least 0.1 N/cm, a dynamic fluid transmission of less than about 0.75 g/m<2> when subjected to an impact energy of about 2400 joules/m<2>, a hydrostatic head of at least 60 cm, and a moisture vapor transmission rate, according to the desiccant method, of at least 2800 g/m<2>/24hr. The moisture vapor permeable film is preferably comprised of at least about 50 % by weight of polymer selected from the group of block copolyether esters, block copolyether amides, polyurethanes, polyvinyl alcohol, and combinations thereof. A method for making such a sheet material is also provided.