Patent ID: 6046297
Filing Date: 2000-04-04
Classification: C08G

Abstract:
A polyurethane elastomer formed by the reaction of an organic diisocyanate prepolymer having low free toluene diisocyanate prepared by a process comprising the steps of:(a) reacting a molar excess of one or more isomers of toluene diisocyanate with a high molecular weight polyol selected from the group consisting of polyalkyleneether polyol and polyester polyol at between about 30.degree. C. and 150.degree. C. for a time sufficient to form a high free toluene diisocyanate prepolymer; and(b) reducing the free toluene diisocyanate level of said high free toluene diisocyanate prepolymer to less than 0.4 percent to form a low free toluene diisocyanate prepolymer; and(c) adding to said low free toluene diisocyanate prepolymer an aliphatic diisocyanate selected from the group consisting of the isomers of 1,1'-methylene-bis-(4-isocyanatocyclohexane), 1,4-cyclohexane diisocyanate, isophorone diisocyanate 1,3-xylylene diisocyanate, or 1,1,4,4-tetramethylxylylene diisocyanate,with a curingly effective amount of a curative containing 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline).