Bayer Aktiengesellschaft

Hans-Joachim Hofer

Josef Pedain

Manfred Schonfelder

Peter Hohlein

Walter Krauss

The present invention is directed to a process for the production of isocyanurate polyisocyanates by the partial trimerization of the isocyanate groups of aliphatic diisocyanates in the presence of catalysts which accelerate the trimerization of isocyanate groups, termination of the trimerization reaction at the particular degree of trimerization required and removal of unreacted starting diisocyanate and, optionally, other volatile constituents, characterized in that at least one diol containing ester groups and having an average molecular weight of 350 to 950 is added to the reaction mixture at any time before removal of the excess starting diisocyanate in a quantity of 1 to 50% by weight, based on the weight of the diisocyanate used as starting material, the type of reactants and the quantitative ratios between them being selected so that, on completion of the reaction, at least 10% by weight free starting diisocyanate is still present in the reaction mixture, not including any inert solvent used, and the molar ratio of isocyanurate groups to urethane groups in the end products is about 20:1 to 0.2:1. The present invention is also directed to the isocyanurate polyisocyanates obtained by this process and the use of these isocyanurate polyisocyanates, optionally blocked by blocking agents for isocyanate groups, for the production of polyurethane plastics, particularly two-component polyurethane lacquers.

Process for the production of isocyanurate polyisocyanates, the

The present invention is directed to polyester polyols in the hydroxyl number range of about 80 to 250 which are based on reaction products of

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Cologne, Germany

Hans-Joachim Hofer