Roofing membrane and method of forming same

Abstract

A roofing membrane is provided including a weft insertion warp knit fabric substrate having continuous filament warp yarns of polyester, polyamide or other suitable synthetic material, continuous filament weft yams of the same or different synthetic material as the warp yams, the warp yams and/or weft yams having a predetermined twist therein, and knit yams warp knit in a chain stitch pattern binding the warp and weft yams together.

That which is claimed:  
     
         1 . A fabric substrate for use in a roofing membrane comprising: 
 warp yarns of synthetic material suitable for use in roofing membranes extending longitudinally of said substrate,    weft yams cross-laid onto said warp yarns and formed of a synthetic material suitable for use in roofing membranes, and    binder yams warp knit in a chain stitch pattern through said cross-laid warp and weft yarns to bind said warp and weft yarns together,    whereby edge curl in said substrate is substantially elminated.    
     
     
         2 . A fabric substrate according to  claim 1  wherein said warp yarns are formed of a synthetic material selected from the group of polyester, polyamide and fiberglass.  
     
     
         3 . A fabric substrate according to  claim 1  wherein said weft yarns are formed of a synthetic material selected from the group of polyester, polyamide and fiberglass.  
     
     
         4 . A fabric substrate according to  claim 2  wherein said werp yarns are formed of high tenacity, low shrink polyester.  
     
     
         5 . A fabric substrate according to  claim 3  wherein said weft yarns are formed of high tenacity, low shrink polyester.  
     
     
         6 . A fabric substrate according to  claim 1  wherein said warp yams and said weft yarns are formed of high tenacity, low shrink polyester.  
     
     
         7 . A fabric substrate according to  claim 1  wherein warp yarns are of a denier within the range of about 750 to about 1250.  
     
     
         8 . A fabric substrate according to  claim 1  wherein said weft yams are of a denier within the range of about 750 to about 1230.  
     
     
         9 . A fabric substrate according to  claim 1  wherein said warp yams and said weft yams are of a denier within the range of about 750 to about 1250.  
     
     
         10 . A fabric substrate according to  claim 1  wherein said warp yams and said weft yams are about 1000 denier.  
     
     
         11 . A fabric substrate according to  claim 1  wherein said weft yams have a twist of at least about 1.5 turns per inch therein.  
     
     
         12 . A fabric substrate according to  claim 1  wherein said warp yams have a twist of at least about 1.5 turns per inch therein.  
     
     
         13 . A fabric substrate according to  claim 1  wherein said warp yams and said weft yams have a twist of at least about 1.5 turns per inch therein.  
     
     
         14 . A fabric substrate for use in a roofing membrane comprising: 
 warp yams of a synthetic material suitable for use in roofing membranes extending longitudinally of said substrate,    weft yams cross-laid onto said warp yams and being formed of a synthetic material suitable for use in roofing membranes,    at least one of said warp yams and said weft yams having a twist of at least about 1.5 turns per inch for more uniform and increased tear strength, and    binder yams warp knit through said cross-laid warp and weft yarns to bind said warp and weft yarns together.    
     
     
         15 . A fabric substrate according to  claim 14  wherein said weft yams have said twist therein and said warp yarns have substantially zero twist therein.  
     
     
         16 . A fabric substrate according to  claim 14  wherein said warp yams have said twist therein and said weft yams have substantially zero twist therein.  
     
     
         17 . A fabric substrate according to  claim 14  wherein said twist is about 2.5 turns per inch.