Bayer Aktiengesellschaft

Ulrich Limna

Werner Rasshofer

Karl-Heinz Dorner

Thomas Munzamy

Compounds containing alcoholic hydroxyl groups suitable as a starting material for the isocyanate polyaddition process by the alcoholysis of polyisocyanate polyaddition products are produced. Polyurethane urea or polyurea waste products having a molar ratio of urea groups to urethane groups of from 1:20 to 1:0 are heated in size reduced form to temperatures of from 120.degree. to 250.degree. C. together with B) polyhyhdric alcohols in the molecular weight range of from 62 to 250 in a ratio by weight of A:B of from 3:1 to 1:10. At least 10% of the polyhydric alcohol B put into the process is subsequently removed by distillation under reduced pressure. A total of up to 1000% by weight, based on the weight of polyurethane urea or polyurea waste A, of one or more polyhydroxy compounds having a molecular weight above 250 which is (are) not volatile under the distillation conditions may optionally be added to the mixture before and/or after removal of the excess alcohol B by distillation. The resulting compounds containing hydroxyl groups may be used as starting material for the production of polyurethane resins by the isocyanate polyaddition process.

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Monheim, Germany

Ulrich Limna