| 摘要 |
The present invention is directed to a polyisocyanate mixture having an NCO content of 10 to 47% by weight and a viscosity of less than 10,000 mPa.s and containing isocyanurate and allophanate groups in a molar ratio of monoisocyanurates to monoallophanates of 10:1 to 1:5, wherein the allophanate groups are formed from urethane groups which are based on the reaction product of an organic diisocyanate having (cyclo)aliphatic bound isocyanate groups and a monoalcohol containing at least carbon atoms and having a molecular weight of 158 to 2500. The present invention is also directed to a process for the production of a polyisocyanate mixture having an NCO content of 10 to 47% by weight, having a viscosity of less than 10,000 mPa.s and containing isocyanurate and allophanate groups in a molar ratio of monoisocyanurates to monoallophanates of 10:1 to 1:5 by a) catalytically trimerizing a portion of the isocyanate groups of an organic diisocyanate having (cyclo)aliphatically bound isocyanate groups b) adding 0.01 to 0.5 moles, per mole of organic diisocyanate, of a monoalcohol containing at least 10 carbon atoms and having a molecular weight of 158 to 2500 to the organic diisocyanate prior to or during the trimerization reaction of step a) and c) terminating the trimerization reaction at the desired degree of trimerization by adding a catalyst poison and/or by thermally deactivating the catalyst. Finally, the present invention is directed to the use of these polyisocyanate mixtures, optionally in blocked form, as an isocyanate component in the two-component coating compositions.
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