Roofing membrane with release liner having enhanced friction characteristics

Abstract

A roofing membrane includes a waterproofing layer, and a release liner removably attached to the waterproofing membrane. The release liner has a coefficient of friction greater than the coefficient of friction of the material of the waterproofing membrane. The release liner is preferably left in place after initial installation of the roofing membrane on a roof, and removed near the end of construction, so that the waterproofing membrane is at least partially protected from damage and dirt during later parts of the construction.

What is claimed is: 
     
         1 . A roofing membrane, comprising:
 a waterproofing layer having a top major surface bounded by four edges; and   a release liner removably attached to and covering or substantially covering the top major surface of the waterproofing layer, the release liner having a coefficient of friction higher than the coefficient of friction of the material of the waterproofing layer.   
     
     
         2 . The roofing membrane of  claim 1 , wherein the kinetic coefficient of friction of the release liner is at least 0.6. 
     
     
         3 . The roofing membrane of  claim 1 , wherein the kinetic coefficient of friction of the release liner is at least 0.7. 
     
     
         4 . The roofing membrane of  claim 1 , wherein the kinetic coefficient of friction of the release liner is at least 0.8. 
     
     
         5 . The roofing membrane of  claim 1 , wherein the kinetic coefficient of friction of the release liner is at least 0.9. 
     
     
         6 . The membrane of  claim 1 , wherein the waterproofing layer comprises one or more materials selected from the group consisting of thermoplastic polyolefin (TPO), ethylene propylene diene monomer (EPDM), polyvinyl chloride (PVC), and modified bitumen. 
     
     
         7 . The membrane of  claim 1 , wherein the release liner includes a chemical additive that raises the coefficient of friction of the release liner as compared to a similar release liner lacking the chemical additive. 
     
     
         8 . The membrane of  claim 7 , wherein the chemical additive is a styrene block copolymer. 
     
     
         9 . The membrane of  claim 1 , wherein portions of the exposed surface of the release liner are raised in relation to other portions. 
     
     
         10 . The membrane of  claim 9 , wherein the raised portions are embossed. 
     
     
         11 . The membrane of  claim 9 , wherein the raised portions comprise randomly oriented bumps. 
     
     
         12 . The membrane of  claim 9 , wherein the raised portions form intersecting lines. 
     
     
         13 . The membrane of  claim 1 , wherein:
 the release liner includes a chemical additive that raises the coefficient of friction of the release liner as compared to a similar release liner lacking the chemical additive; and   portions of the exposed surface of the release liner are raised in relation to other portions.   
     
     
         14 . The membrane of  claim 1 , wherein the release liner covers the top major surface of the waterproofing layer. 
     
     
         15 . The membrane of  claim 1 , wherein the release liner substantially covers the top major surface of the waterproofing layer, leaving uncovered a strip of the top major surface of the waterproofing layer at one edge of the top major surface. 
     
     
         16 . The membrane of  claim 1 , wherein the release liner is removably attached to the waterproofing layer without the use of an adhesive. 
     
     
         17 . The membrane of  claim 16 , wherein the release liner is attached to the waterproofing layer using heat and pressure. 
     
     
         18 . The membrane of  claim 16 , wherein the release liner includes a tackifier. 
     
     
         19 . The membrane of  claim 1 , wherein the release liner is removably attached to the waterproofing layer using an adhesive. 
     
     
         20 . The membrane of  claim 1 , wherein the release liner is removably attached to the waterproofing layer using static cling. 
     
     
         21 . A method of applying a roofing membrane on a roof, the method comprising:
 laying a first row of roofing membrane on the roof, the first row of roofing membrane including a first waterproofing layer and a first release liner on top of a top major surface of the first waterproofing layer, the first release liner having a coefficient of friction higher than that of the material of the first waterproofing layer; and   laying a second row of roofing membrane on the roof, the second row of roofing membrane having a second waterproofing layer and a second release liner, the second release liner having a coefficient of friction higher than that of the material of the second waterproofing layer, the second row of roofing membrane overlapping the first row such that a bottom major surface of the second waterproofing layer contacts an uncovered strip at one edge of the top major surface of the first waterproofing layer; and   bonding the first and second rows of roofing membrane together in their area of overlap.   
     
     
         22 . The method of  claim 21 , further comprising uncovering the strip of the top major surface of the first waterproofing layer by peeling back a portion of the first release liner. 
     
     
         23 . The method of  claim 22 , further comprising removing the portion of the first release liner by tearing the first release liner along a perforation. 
     
     
         24 . The method of  claim 21 , wherein the release liner of the first row of roofing membrane substantially covers the top major surface of the first waterproofing layer, leaving uncovered the strip of the top major surface of the first waterproofing layer. 
     
     
         25 . The method of  claim 21 , further comprising removing the first and second release liners. 
     
     
         26 . A method of making a roofing membrane, the method comprising:
 providing a polymeric waterproofing layer having a top major surface; and   removably attaching a release liner to the top major surface of the waterproofing layer, the release liner having a coefficient of friction higher than that of the material of the waterproofing layer.   
     
     
         27 . The method of  claim 26 , wherein removably attaching the release liner to the waterproofing layer comprises placing an adhesive between the waterproofing layer and the release liner. 
     
     
         28 . The method of  claim 26 , further comprising embossing the release liner.