Polyureas and preparation thereof

Abstract

The invention disclosed is a method for preparing new improved polyureas from polyisocyanates and polyamines. The product polyureas are characteristically tough, abrasion resistant resins having broad spectrum utility.

What is claimed is: 
     
       1. A method for preparing aqueous polyurea solution which consists essentially of preparing a non-crosslinked polyurea by reacting a first component comprising .Iadd.a poly(oxyalkylene) polyol capped with polyisocyanate, said .Iaddend.polyisocyanate selected from the group consisting of polyaryl polyisocyanate, tolylene diisocyanate, triphenylmethane-4,4'4",-triisocyanate, benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, diphenyl-2,4,4'-triisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, diphenylmethane-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, xylene-alpha,alpha'-diisothiocyante, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'biphenylene diisocyanate, 2,2',5,5'-tetramethyl-4,4'-biphenylene diisocyanate, 4,4'-methylenebis (phenylisocyanate)c 4,4'-sulfonylbis (phenylisocyanate), 4,4'-methylene di-orthotolylisocyanate, ethylene diisocyanate, ethylene diisothiocyanate, trimethylenediisocyanate and the like; and a second component comprising polyamine having from about 2 to about 23 pendant amine groups in a non-protonic carbonyl containing solvent selected from the group consisting of acetone, methyl ethyl ketone, cyclohexanone, acetaldehyde, propionaldehyde, butyradelhyde, and isobutyraldehyde; said polyamine and said solvent being first combined for from about 2 minutes to about 24 hours at temperature of -5° C. to about 150° C.; the molar ratio of isocyanate groups in the polyisocyanate to amine groups in the polyamine being from about 1:1 to about 1:20 isocyanate to amine; adding water and removing the solvent from the non-crosslinked polyurea. 
     
     
       2. The method of claim 1 wherein curing of the non-crosslinked polyurea is effected by removing the added water thereby preparing a tough insoluble crosslinked polyurea. 
     
     
       3. The aqueous polyurea composition prepared by the method of claim 1. 
     
     
       4. The tough insoluble crosslinked polyurea prepared by the method of claim 2. 
     
     
       5. The method of claim 1 wherein an intermediate crosslinking agent is introduced into the aqueous non-crosslinked solution, said crosslinking agent being a member of the group consisting of epichlorohydrin, formaldehyde, 1,4-dichlorobutene, B,B'-dichloroethylether, acetaldehyde, chloral and the like. 
     
     
       6. The method of claim 5 wherein curing of the non-crosslinked polyurea is effected by removing the added water thereby preparing a tough insoluble crosslinked polyurea. 
     
     
       7. The aqueous polyurea composition prepared by the method of claim 5. 
     
     
       8. The tough insoluble crosslinked polyurea prepared by the method of claim 6. 
     
     
       9. The method of claim 1 wherein after polyamine and said solvent are first combined for from about 2 minutes to about 24 hours at a temperature of about -5° C. to about 150° C., the resultant combination is maintained at a temperature of about 0° C. to about 25° C. during which said polyisocyanate at a temperature in the range of about 0° C. to about 25° C. is added. 
     
     
       10. The method of claim 1 wherein the product is stirred at about 0° C. to about 100° C. for about 2 minutes to about 8 hours to effect polymerization to essentially non-crosslinked polyureas. 
     
     
       11. The method of claim 1 wherein the polyamine is selected from the group consisting of diethylenetriamine, triethylene-tetramine, tetraethylenepentamine, polyethyleneimine, tolylene-2,4,6-triamine, ethylene diamine, N,N'-dimethylethylent diamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, propylene diamine, dipropylene triamine, 1,3 diamino butane and the like.