| 摘要 |
The present invention is directed to a polyisocyanate mixture i) having an NCO content of 5 to 35% by weight and prepared from an organic diisocyanate, ii) containing up to 25% by weight of isocyanurate groups (calculated as N3,C3,O3, MW 126), iii) containing allophanate groups in an amount such that there are more equivalents of allophanate groups than urethane and urea groups and such that the polyisocyanate mixture remains stable and homogeneous in storage for 3 months at 25.degree.C and iv) containing siloxane groups (calculated as SiO, MW 44) in an amount of 0.002 to 50% by weight, wherein the preceding percentages are based on the solids content of the polyisocyanate mixture, excluding any unreacted organic diisocyanate, and wherein the siloxane groups are incorporated by reacting an isocyanate group with a compound containing two or more isocyanate-reactive groups directly attached to carbon atoms and one or more siloxane groups. The present invention is also directed to a process for the production of this polyisocyanate mixture and to its use, optionally in blocked form, as an isocyanate component in one- or two-component coating compositions.
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