| abstract |
The present invention relates to a novel process for the preparation of polyaddition products, to the products obtainable by this process and to their use as starting components in the production of polyurethane plastics. The process includes the reaction of A) polyisocyanates with uretdione groups having a mean isocyanate functionality of at least 2.0, optionally with the concomitant use of B) other diisocyanates and/or polyisocyanates, different from A, in an amount of up to 70 wt.%, based on the total weight of components A) and B), with C) polyols in the molecular weight range 62 - 2000 having a mean functionality of at least 2.0, or mixtures of polyols and optionally D) other isocyanate-reactive monofunctional compounds in an amount of up to 40 wt.%, based on the total weight of components C) and D). An equivalent ratio of isocyanate groups to isocyanate- reactive groups of 1.8:1 to 0.6:1 is maintained in the reactants, and the reaction is carried out in the presence of at least one bismuth-containing catalyst. |