Air-permeable composite fabric

Abstract

An air-permeable composite fabric is provided. The composite fabric has an inner fabric layer, an outer fabric layer, and an intermediate vapor barrier. The vapor barrier is selected from adhesive material and an adhesive/membrane combination designed so the composite fabric has a level of air permeability to allow air flow between the first fabric layer and the second fabric layer and a variable level of water vapor diffusion resistance that decreases as air speed impinging on the composite fabric increases.

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;    said intermediate, air-permeable barrier layer being selected from the group consisting of: a foamed adhesive in the form of a discontinuous film, an adhesive in the form of a continuous film mechanically altered by one of crushing and stretching, and a membrane disposed between and adhered to said first fabric layer and said second fabric layer with an adhesive and mechanically altered by stretching,    said intermediate, air-permeable vapor barrier layer having 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 having 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 adhesive is selected from the group consisting of polyurethane, acrylics, polyamides, polyesters and combinations thereof.  
     
     
         3 . The air-permeable composite fabric of  claim 1 , wherein at least one of said first fabric layer and said second fabric is rendered hydrophilic.  
     
     
         4 . 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.  
     
     
         5 . The air-permeable composite fabric of  claim 1 , wherein said intermediate, air-permeable vapor barrier comprises an adhesive selected from the group consisting of: an adhesive in the form of a mechanically altered continuous film and a foamed adhesive in the form of a discontinuous film.  
     
     
         6 . The air-permeable composite fabric of  claim 5 , wherein said vapor barrier is exclusively foamed adhesive in the form of a discontinuous film.  
     
     
         7 . The air-permeable composite fabric of  claim 1 , wherein said intermediate, air-permeable vapor barrier comprises the membrane disposed between said first fabric layer and said second fabric layer and adhered thereto with an adhesive and mechanically altered by stretching, said composite fabric having undergone mechanical processing.  
     
     
         8 . The air-permeable composite fabric of  claim 1  or  claim 7 , wherein said membrane is made from a material selected from the group consisting of polyurethane, polyamide, polytetrafluoroethylene, polyester and combinations thereof.  
     
     
         9 . The air-permeable composite fabric of  claim 7  wherein said mechanical processing comprises controlled stretching.  
     
     
         10 . The air-permeable composite fabric of  claim 1 ,  claim 5  or  claim 7 , wherein said adhesive is selected from the group consisting of polyurethane, acrylics, polyamides, polyesters and combinations thereof.  
     
     
         11 . A method of forming an air-permeable composite fabric comprising the steps of: selecting a vapor barrier from the group consisting of a membrane and an adhesive, 
 disposing the vapor barrier between a first fabric layer and a second fabric layer in order to produce the composite fabric, and    mechanically processing the composite fabric of such that the intermediate, air-permeable vapor barrier layer has a level of air permeability to allow air flow between the first fabric layer and the second fabric layer and the intermediate, air-permeable vapor barrier layer has a variable level of water vapor diffusion resistance that decreases as air speed impinging on the composite fabric increases.    
     
     
         12 . The method of  claim 11 , wherein said vapor barrier is a membrane, and wherein the step of mechanical processing comprises controlled stretching of the composite fabric.  
     
     
         13 . The method of  claim 11 , wherein said vapor barrier is an adhesive, and the step of mechanical processing comprises applying pressure to the composite fabric.  
     
     
         14 . The method of  claim 13 , comprising passing the composite fabric through a plurality of rollers while applying pressure.  
     
     
         15 . The method of  claim 13 , comprising passing the composite fabric through a plurality of heated rollers while applying pressure.  
     
     
         16 . The method of  claim 14  or  claim 15 , comprising passing the composite fabric through the rollers at variable controlled speeds.  
     
     
         17 . The method of  claim 13 , wherein the adhesive is foamed.  
     
     
         18 . The method of  claim 13 , comprising disposing the adhesive between the first fabric layer and the second fabric layer by transfer coating using release paper.  
     
     
         19 . The method of  claim 11 , comprising disposing the vapor barrier between the first fabric layer and the second fabric layer as a continuous film of adhesive.  
     
     
         20 . The method of  claim 11 , comprising disposing the vapor barrier between the first fabric layer and the second fabric layer as a discontinuous film of adhesive.  
     
     
         21 . The method of  claim 11 , comprising disposing the vapor barrier between the first fabric layer and the second fabric layer as a film of adhesive using release paper.  
     
     
         22 . The method of  claim 11 , comprising disposing the vapor barrier between the first fabric layer and the second fabric layer by applying the adhesive directly to at least one of the first fabric layer and the second fabric layer.