Breathable composite sheet structure

A moisture vapor permeable, substantially liquid impermeable composite sheet material comprising:

• a fibrous nonwoven substrate, said substrate having opposite first and second planar sides, and said substrate consisting essentially of a blend of between 20% and 80% by weight polyolefin polymer fibers and between 20% and 80% by weight polyester polymer fibers;
• a moisture vapor permeable thermoplastic film bonded to the first side of said fibrous substrate, said moisture vapor permeable film having an average thickness of less than 25 microns and consisting essentially of a copolyether ester elastomer;
• said composite sheet exhibiting a peel strength of at least 0.1 N/cm, a dynamic fluid transmission of less than about 0.75 g/m2 when subjected to an impact energy of about 2400 joules/m2, a hydrostatic head of at least 60 cm, and having a moisture vapor transmission rate, according to the desiccant method, of at least 2800 g/m2/24 hr.

A moisture vapor permeable, substantially liquid impermeable composite sheet material comprising:

• a fibrous nonwoven substrate, said substrate having opposite first and second planar sides;
• a moisture vapor permeable thermoplastic film bonded to the first side of said fibrous substrate, said moisture vapor permeable film having an average thickness of less than 25 microns, said moisture vapor permeable film being bonded to the fibrous substrate with a hotmelt adhesive applied between the fibrous nonwoven substrate and the moisture vapor permeable film at an adhesive basis weight between 0.5 and 5 mg/in2, said adhesive contacting less than 75% of the surface of the first side of the fibrous substrate;
• said composite sheet exhibiting a peel strength of at least 0.1 N/cm, a dynamic fluid transmission of less than about 0.75 g/m2 when subjected to an impact energy of about 2400 joules/m2, a hydrostatic head of at least 60 cm, and having a moisture vapor transmission rate, according to the dessicant method, of at least 2800 g/m2/24 hr.