Air-Permeable Composite Fabric

1 . An air-permeable composite fabric comprising:

a first fabric layer;

a second fabric layer; and

an intermediate, air-permeable vapor barrier disposed between and bonded to said first fabric layer and said second fabric layer, wherein:

said intermediate, air-permeable barrier layer is a continuous film mechanically altered by crushing the composite fabric between a plurality of rollers;

said intermediate, air-permeable vapor barrier layer has a level of air permeability to allow air flow between said first fabric layer and said second fabric layer, and

said intermediate, air-permeable vapor barrier layer has a variable level of water vapor diffusion resistance that substantially decreases as air speed of moving air impinging on said composite fabric increases.

2 . The air-permeable composite fabric of claim 1 , wherein said membrane is made from a material selected from the group consisting of polyurethane, polyamide, polytetrafluoroethylene, polyester and combinations thereof.

3 . The air-permeable composite fabric of claim 1 , wherein said intermediate, air-permeable barrier layer is a continuous film mechanically altered by crushing the composite fabric between a plurality of rollers that are heated.

4 . The air-permeable composite fabric of claim 3 , wherein said plurality of rollers are heated to a temperature of between about 100° F. and 375° F.

5 . The air-permeable composite fabric of claim 1 , wherein at least one of said first fabric layer and said second fabric layer has a raised surface.

6 . The air-permeable composite fabric of claim 1 , wherein said intermediate, air-permeable vapor barrier is adhered to said first fabric layer and said second fabric layer with an adhesive.

7 . The air-permeable composite fabric of claim 6 , wherein said adhesive is selected from the group consisting of polyurethane, acrylics, polyamides, polyesters and combinations thereof.