Abstract: The invention relates to polyurethanes obtainable by reaction of (a) polyisocyanates A selected from modified or unmodified 4,4?-methanediphenyl diisocyanate, higher nuclear homologs of 4,4?-methanediphenyl diisocyanate, isocyanated groups containing prepolymers based on 4,4?-methanediphenyl diisocyanate, and mixtures thereof, with (b) compounds having at least two isocyanate-reactive hydrogen atoms, comprising (b1) block copolymers formed from a polybutadienol and a cyclic ester as component B1, and (b2) low molecular weight extenders or crosslinkers each having a molecular weight of 62 to 500 g/mol as component B2.

Abstract: The invention relates to a process for the production of polybutadienols from polybutadienes with number-average molar mass from 300 to 2000 g/mol comprising from 20 to 50% of 1,4 double bonds and from 50 to 80% of 1,2 vinylic and 1,2 cyclovinylic double bonds, based on the quantity of all of the double bonds, comprising the steps of i) epoxidation of some or all of the 1,4 double bonds with an epoxidizing reagent which selectively epoxidizes 1,4 double bonds, ii) reaction of the epoxidized polybutadiene with an alcohol or water to give a polybutadienol.

Abstract: The invention relates to polyurethanes obtainable by reaction of (a) polyisocyanates A selected from modified or unmodified 4,4?-methanediphenyl diisocyanate, higher nuclear homologs of 4,4?-methanediphenyl diisocyanate, isocyanated groups containing prepolymers based on 4,4?methandiphenyl diisocyanate, and mixtures thereof, with (b) compounds having at least two isocyanate-reactive hydrogen atoms, comprising (b1) block copolymers formed from a polybutadienol and a cyclic ester as component B1, and (b2) low molecular weight extenders or crosslinkers each having a molecular weight of 62 to 500 g/mol as component B2.