Isocyanate Prepolymer Catalysts And Related Curing Processes

Abstract

Isocyanate prepolymer catalysts and processes for rapidly curing isocyanate prepolymers are disclosed herein. Substrates coated with the isocyanate prepolymers are treated with a drying agent and water, which combine to form a hydrated catalyst complex. Co-catalysts, such as organo tins, may be used to further enhance the curing rate.

1 . A process for forming a dried coating upon a substrate comprising:
 applying a wet coating to a surface of the substrate, the wet coating including an isocyanate prepolymer; and   polymerizing the wet coating by providing an atmosphere including a drying agent/co-catalyst complex and relative humidity in a range of about 40-80%,   wherein the isocyanate prepolymer is selected from the group consisting of urethanes, ureas, biurets, allophanates, and combinations thereof;   the drying agent is selected from the group consisting of ammonia, amines, alkanolamines, and combinations thereof; and   the co-catalyst is selected from the group consisting of organometallics, inorganic metal salts, and combinations thereof.   
     
     
         2 . The process of  claim 1 , wherein the co-catalyst comprises an organo tin. 
     
     
         3 . The process of  claim 1 , wherein the co-catalyst comprises dibutyl tin dilaurate. 
     
     
         4 . The process of  claim 1 , wherein the drying agent comprises an amine. 
     
     
         5 . The process of  claim 1 , wherein the drying agent/co-catalyst complex comprises a dimethylethanolamine-dibutyl tin dilaurate complex. 
     
     
         6 . The process of  claim 1 , wherein the drying agent and water vapor form a hydrated catalyst complex having about a 5:1 water to drying agent molar ratio. 
     
     
         7 . The process of  claim 6 , wherein the hydrated catalyst complex is present in an amount from about 1 to 5000 ppm. 
     
     
         8 . The process of  claim 6 , wherein the hydrated catalyst complex is present in an amount from about 10 to 2500 ppm. 
     
     
         9 . The process of  claim 6 , wherein the hydrated catalyst complex is present in an amount from about 100 to 1000 ppm. 
     
     
         10 . A catalyst for the polymerization of isocyanates, the catalyst comprising:
 a drying agent selected from the group consisting of ammonia, amines, alkanolamines, and combinations thereof; and   a co-catalyst selected from the group consisting of organometallics, inorganic metal salts, and combinations thereof,   wherein the drying agent and the co-catalyst form a vapor phase complex.