초록 ▼

Highly stable, segmented, aliphatic polyurethanes prepared by particular processes are disclosed. The segmented polyurethanes of this invention are substantially free of ester and ether linkages and are found to be particularly hydrolytically and oxidatively stable. The polyurethanes of this inventi

Highly stable, segmented, aliphatic polyurethanes prepared by particular processes are disclosed. The segmented polyurethanes of this invention are substantially free of ester and ether linkages and are found to be particularly hydrolytically and oxidatively stable. The polyurethanes of this invention are prepared by a particular two stage process involving the formation of a prepolymer and subsequent reaction with simultaneously or sequentially added diisocyanate and diol monomers.

대표청구항 ▼

A segmented polyurethane comprising: alternating softer and harder segments linked by urethane groups; wherein said softer segments comprise a polyurethane having the formula (－O or －OCNH)－(R1－U－R2－U)m－R1－(O－or NHCO－), wherein one of R1 and R2 signifies a dimer backbone, U signifies a urethane group

A segmented polyurethane comprising: alternating softer and harder segments linked by urethane groups; wherein said softer segments comprise a polyurethane having the formula (－O or －OCNH)－(R1－U－R2－U)m－R1－(O－or NHCO－), wherein one of R1 and R2 signifies a dimer backbone, U signifies a urethane group and the other of R1 and R2 signifies a hydrocarbon moiety free of ether and ester groups and having a molecular weight less than about 1000, and the average value of m is approximately 1 or greater; and wherein said harder segments comprise a polyurethane having the general formula (－O or －OCNH)－(R3－U－R4－U)n－R3－(O－or NHCO－), wherein R3 and R4 both signify hydrocarbon moieties free of ether and ester groups and having molecular weights less than about 500, U signifies a urethane group and the average value of n is approximately 1 or greater.