Patent ID: 8454784

Claim:
A method of forming an air-permeable composite fabric, said method comprising the steps of: providing a first fabric layer; providing a second fabric layer; providing an adhesive layer comprising a continuous unfoamed film of polyurethane in an amount of about 0.25 oz/yd 2 between the first fabric layer and the second fabric layer; and calendering together the first fabric layer, the second fabric layer and the adhesive layer to provide the air-permeable composite fabric, wherein the calendering step comprises passing the first fabric layer, the second fabric layer and the adhesive layer through a plurality of rollers at a temperature, a pressure and a speed selected to enhance an air permeability of the adhesive layer and provide the fabric with a predetermined air permeability and a resistance to vapor permeability that decreases with increasing air flow, and no pressure applied during the calendering step is lower than 10 lbs/in 2 or higher than 150 lbs/in 2 .