主权项 |
1. A polyisocyanate based adhesive obtained by reacting, in the presence of a trimerisation catalyst, (i) a polymeric polyisocyanate or a prepolymeric polyisocyanate having an isocyanate content of 6 to 30 wt. % with (ii) a polyol selected from a polyether polyol, a polyester polyol and a combination thereof; wherein component (i) is the reaction product of an organic polyisocyanate and a compound containing isocyanate-reactive hydrogen atoms selected from a monohydric alcohol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonane diol, 2-methyl-1,8-octanediol, a polyester polyol, a mercaptan, a carboxylic acid, an amine, urea, an amide and a mixture thereof; wherein the trimerisation catalyst is selected from the group consisting of alkali metal salts of carboxylic acids; wherein the adhesive has a softblock content between 40 and 60 wt %; and wherein component (ii) does not comprise an amine compound and wherein component (i) and component (ii) are miscible with each other. |