Nonwoven fibrous mats and methods

Abstract

A water proof membrane containing high strength fibers bonded together with one or more urethanes is disclosed along with the methods of making including wet or dry laying the high strength fibers to form a web, applying an aqueous urethane medium to the web and drying the web and super calendaring the web, or the web can be formed by forming a web by any method from bicomponent core/sheath fibers, the sheath comprising one or more urethanes, followed by super calendaring.

1 . A membrane of waterproof, but water vapor permeable protective material comprising high strength fibers bonded together with a matrix of one or more urethane compounds, the one or more urethane compounds selected to have; 
 a) a high to the highest maximum water vapor transmission rate,    b) good thermoplasticity to permit good hot super calandering,    c) good elongation, toughness, and elasticity, to resist damage when stretched, and    d) tendency to swell on contact with water to provide good seals around penetrating fasteners.    
   
   
       2 . The membrane of  claim 1  wherein the membrane comprises a major portion by weight of high strength fibers and a minor portion of one or more urethane compounds.  
   
   
       3 . The membrane of  claim 1  wherein the membrane comprises about 51-90 wt. percent of high strength fibers and about 10-49 wt. percent polyurethane.  
   
   
       4 . The membrane of  claim 1  wherein the membrane comprises about 51-70 wt. percent of high strength fibers and about 30-49 wt. percent polyurethane.  
   
   
       5 . The membrane of  claim 1  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       6 . The membrane of  claim 2  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       7 . The membrane of  claim 3  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       8 . The membrane of  claim 4  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       9 . A method of making a membrane of waterproof, but water vapor permeable protective material comprising high strength fibers bonded together with a matrix of one or more urethane compounds, the one or more urethane compounds selected to have; 
 a) a high to the highest maximum water vapor transmission rate,    b) good thermoplasticity to permit good hot super calandering,    c) good elongation, toughness, and elasticity, to resist damage when stretched, and    d) tendency to swell on contact with water to provide good seals around penetrating fasteners,    the method comprising forming a web of high strength fibers, applying the above urethane or mixture of urethanes in an aqueous medium, onto the web, drying the web and super-calendaring at a temperature high enough to make the urethane at a temperature high enough to make the urethane plastic, but not so high that the high strength fibers are damaged, to form the membrane.    
   
   
       10 . The method of  claim 9  wherein the membrane comprises a major portion by weight of high strength fibers and a minor portion of one or more urethane compounds.  
   
   
       11 . The method of  claim 9  wherein the membrane comprises about 51-90 wt. percent of high strength fibers and about 10-49 wt. percent polyurethane.  
   
   
       12 . The method of  claim 9  wherein the membrane comprises about 51-70 wt. percent of high strength fibers and about 30-49 wt. percent polyurethane.  
   
   
       13 . The method of  claim 9  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       14 . A method of making a membrane of waterproof, but water vapor permeable protective material comprising high strength fibers bonded together with a matrix of one or more urethane compounds, the one or more urethane compounds selected to have; 
 a) a high to the highest maximum water vapor transmission rate,    b) good thermoplasticity to permit good hot super calandering,    c) good elongation, toughness, and elasticity, to resist damage when stretched, and    d) tendency to swell on contact with water to provide good seals around penetrating fasteners,    the method comprising forming a web of core/sheath fibers, the core being a high strength fiber and the sheath comprising a urethane and super-calendaring the web at a temperature high enough to make the urethane plastic, but not so high that the high strength fibers are damaged, to form the membrane.    
   
   
       15 . The method of  claim 14  wherein the membrane comprises a major portion by weight of high strength fibers and a minor portion of one or more urethane compounds.  
   
   
       16 . The method of  claim 14  wherein the membrane comprises about 51-90 wt. percent of high strength fibers and about 10-49 wt. percent polyurethane.  
   
   
       17 . The method of  claim 15  wherein the membrane comprises about 51-70 wt. percent of high strength fibers and about 30-49 wt. percent polyurethane.  
   
   
       18 . The method of  claim 14  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       19 . The method of  claim 15  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.  
   
   
       20 . The method of  claim 17  wherein the high strength fibers are selected from a group consisting of glass fibers, synthetic fibers of one or more high strength synthetic polymers such as a nylon 6, nylon 66, polypropylene, a polyester and many other high strength polymers or mixtures thereof, carbon fibers, ceramic fibers and amorphous silica fibers.