Polyurethane-ureas based on cis-trans-1,4-diaminocyclohexane

Abstract

Light stable polyurethane coatings with a considerably increased softening range and melting points coupled with improved resistance to perchlorethylene is obtained by using a chain extender comprising at least 80 mol % 1,4-diamino cyclohexane with a cis/transisomer ratio of from 10/90 to 60/40 .Iadd.and by using aliphatic or cycloaliphatic diisocyanates wherein such diisocyanates consist of at least 75 mol percent of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane.Iaddend..

What is claimed is: 
     
       1. A polyurethane polyurea prepared by a process which comprises, reacting in an inert organic solvent a a. chain extender comprising at least 80 mol % 1,4-diamino cyclohexane with a cis/trans-isomer ratio of from 10/90 to 60/40, with   b. an isocyanato terminated prepolymer prepared by a process which comprises reacting i. substantially linear polyhydroxyl compounds with molecular weights of from 500 to 5000, with   ii. aliphatic or cycloaliphatic diisocyanates, .Iadd.wherein such diisocyanates consist of at least 75 mol % of 1-isocyanato-3-isocyanato methyl-3,5,5-trimethyl cyclohexane, the .Iaddend.molar ratio of hydroxyl groups to isocyanate groups being between about 1 : 1.5 and 1 : 5, and evaporating the solvent.       
     
     
       2. The product of claim 1 wherein the solvent used is a mixture of an aromatic hydrocarbon, or chlorinated aliphatic hydrocarbon, with primary secondary or tertiary aliphatic alcohols. 
     
     
       3. A product according to claim 1 wherein the isocyanato terminated prepolymers are prepared from substantially linear polyhydroxyl compounds with molecular weights of from about 62 to 400. 
     
     
       4. The product of claim 1 wherein the prepolymers, diamines and chain extenders are reacted in a solvent mixture of chlorinated aromatic hydrocarbons. 
     
     
       5. The product of claim 1 wherein the polyhydroxyl compounds are dihydroxy polyesters, polycarbonates or polyacetones. 
     
     
       6. The product of claim 1 wherein the prepolymer includes diols with a tertiary amino group. .[.7. The product of claim 1 wherein the diisocyanate mixture contains at least 75 mol % of 
     
     
        1-isocyanato-3-isocyanato methyl-3,5,5-trimethyl cyclohexane..]. 8. The product of claim 1 wherein the molar ratio of isocyanate groups to amine groups in the chain extending reaction is between 1 : 1.0 and 1 : 1.15. 
     
     
           The product of claim 1 wherein polyhydroxyl compound has a molecular weight of from 800 to 3000 and a melting point below 45° C by the 
     
     
        Kofler Bench method. 10. The product of claim 1 wherein the prepolymer includes a dihydroxy polyester selected from the group adipic acid-ethylene glycol, -1,6-hexane diol, -2,2-dimethyl propane diol, -1,4-butane diol or -1,2-propane diol.