| 摘要 |
The present invention is directed to a polyisocyanate mixture (i) having an NCO content of 5 to 35 percent by weight and prepared from an organic diisocyanate, (ii) containing up to 25 percent 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 or 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 percent 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 one isocyanate-reactive group directly attached to a carbon atom 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.
|
