| 摘要 |
A polyisocyanate composition with an average functionality above 3, more preferably above 3.5 and most preferably above 4 obtained by polycondensation of diisocyanate or triisocyanate monomers. The polyisocyanate composition comprises: (a) 0-5 wt.% with respect to the total of (a), (b) and (c) of compounds bearing a single uretidine dione functional group with a mol. wt. equal to at least twice the average mol. wt. of the isocyanate monomers having the highest mol. wt.; (b) 0-45 wt.% with respect to the total of (a), (b) and (c) of compounds having a single isocyanurate functional group and with a mol. wt. equal to at least three times the average mol. wt. of the isocyanate monomer with the highest mol. wt.; (c) at least 40 wt.% with respect to the total of (a), (b) and (c) of a mixture of polyisocyanates having a mol. wt. equal to at least 3 times the average mol. wt. of the isocyanate monomers having the lowest mol. wt. and bearing at least two isocyanate functional groups, the mixture comprising (i) compounds bearing at least two isocyanurate functional groups; (ii) compounds bearing at least two uretidine dione functional groups; (iii) compounds bearing at least one isocyanurate and at least one uretidine dione functional group with a mol. wt. higher than three times the highest mol. wt. of the isocyanate monomers and having the ratio carbonyl groups belonging to a uretidine dione cycle/carbonyl group belonging to an isocyanurate cycle + carbonyl groups belonging to an uretidine dione cycle of at least 4%; (d) 0-25 wt.% with respect to the total (a) to (e) of compounds bearing at least one isocyanate group different from (a), (b) and (c); (e) 0-10 wt.% with respect to (a) to (e) of impurities (catalyst residues and/or side products). Independent claims are also included for the following: (1) A reactive coating composition comprising the composition and a polyol compound with a hydroxyl number 50-250 and mol. wt. 500-15000. (2) A method of manufacture of an article comprising the application of the coating composition to at least one surface of a substrate and crosslinking. (3) A coating comprising the crosslinking of the composition. (4) An article comprising a substrate possessing a surface and a coating of the coating composition. |
