Polyurethane coating process for carpet backing

Abstract

A method for preparing carpet by using polyurethane to anneal secondary backing to a greige, comprising fibers attached to a primary backing. The polyurethane monomers are mixed just prior to application to the greige primary backing allowing the relatively low viscosity polyurethane to penetrate the fibers of the primary backing to aid in fiber lock. The polyurethane coated greige is then contacted with the secondary backing before complete polymerization to insure sufficient tack to hold the backings together.

What is claimed is:  
     
         1 . A method for preparing carpet by annealing a secondary backing to a greige, having fibers attached to a primary backing, said process comprising: 
 a) preparing polyurethane by introducing polyol from a first dedicated line and an isocyanate from a second dedicated line into a mixing head for spray application;    b) applying said polyurethane to the primary backing side of said greige to form a tacky polyurethane-coated greige; and    c) contacting said secondary backing with the polyurethane-coated greige to form a carpet.    
     
     
         2 . The process of  claim 1  wherein said greige is subjected to steam after coating with polyurethane and prior to contact with the secondary backing.  
     
     
         3 . The process of  claim 1  wherein said polyurethane is applied to said primary backing at an area concentration of about 1.0 g/m 2  to about 30 g/m 2 .  
     
     
         4 . The process of  claim 1  wherein filler is present in the polyurethane in a concentration of from about 0 to about 300 parts per 100 parts of polyol.  
     
     
         5 . The process of  claim 1  wherein metallic or organic amine catalysts or a mixture thereof are introduced through a third dedicated line into said mixing head for spray application.  
     
     
         6 . The process of  claim 1  wherein a thermal rise of less than 30° F. is observed.  
     
     
         7 . The process of  claim 1  wherein said polyurethane applied to said primary backing is flame retardant.  
     
     
         8 . The process of  claim 1  wherein said polyurethane applied to said primary backing contains 0.5 to 5 parts water per 100 parts of polyol.  
     
     
         9 . A method for preparing carpet by annealing a secondary backing to a greige, having face fibers extending from a first side of a primary backing, said process comprising: 
 a) preparing polyurethane by introducing polyol from a first dedicated line and an isocyanate from a second dedicated line into a mixing head for spray application;    b) applying said polyurethane to a second opposed side of the primary backing of said greige to form a tacky polyurethane-coated greige;    c) applying steam to the polyurethane coated primary backing; and    d) contacting said secondary backing with the polyurethane-coated greige to form a carpet.    
     
     
         10 . The process of  claim 9  wherein said polyurethane is applied to said primary backing at an area concentration of about 1.0 g/m 2  to about 30 g/m 2 .  
     
     
         11 . The process of  claim 9  wherein the filler is present in said polyurethane at a concentration of from about 0 to about 300 parts per 100 parts of polyol.  
     
     
         12 . The process of  claim 9  wherein metallic or amine catalysts or a mixture thereof are introduced through a third dedicated line into said mixing head for spray application.  
     
     
         13 . The process of  claim 9  wherein a thermal rise of less than 30° F. is observed.  
     
     
         14 . The process of  claim 9  wherein said polyurethane applied to said primary backing is flame retardant.  
     
     
         15 . The process of  claim 9  wherein said polyurethane applied to said primary backing contains 0.5 to 5 parts water per 100 parts of polyol.  
     
     
         16 . A method for preparing carpet by annealing a secondary backing to a greige, having fibers attached to a primary backing, said process comprising: 
 a) preparing polyurethane by mixing a polyol component and an isocyanate component at about the same time the components are introduced into a mixing head for spray application;    b) applying said polyurethane at ambient temperature to the primary backing side of said greige to form a tacky polyurethane-coated greige;    c) applying steam to the polyurethane coated primary backing; and    d) contacting said secondary backing with the polyurethane-coated greige to form a carpet.    
     
     
         17 . The process of  claim 16  wherein said polyurethane is applied to said primary backing at an areal concentration of about 1.0 g/m 2  to about 30 g/m 2 .  
     
     
         18 . The process of  claim 16  wherein the filler is present at a concentration of from about 0 to about 300 parts per 100 parts of polyurethane.  
     
     
         19 . The process of  claim 16  wherein metallic or amine catalysts or a mixture thereof are introduced into said mixing head for spray application.  
     
     
         20 . The process of  claim 1  wherein a thermal rise of less than 30° F. is observed.