Abstract: A process for preparing a polyisocyanurate polyurethane material, which process comprises reacting a polyisocyanate and an isocyanate-reactive composition, wherein the reaction is conducted at an isocyanate index of 1600 to 100,000 and in the presence of a trimerization catalyst, wherein the polyisocyanate comprises a) 75-100% by weight of diphenylmethane diisocyanate comprising at least 40%, preferably at least 60% and most preferably at least 85% by weight of 4,4?-diphenylmethane diisocyanate and/or a variant of said diphenylmethane diisocyanate which variant is liquid at 25° C.

Abstract: Process for making a polyisocyanurate composite which process comprises combining a polyisocyanate, a polyether polyol and a trimerization catalyst with a to-be-bonded material to form a reactive composite, and allowing in a next step this reactive composite to react at elevated temperature, wherein the amount of the reactive binder composition is 1-60% by weight and the amount of the to-be-bonded material is 40-99% by weight, both calculated on the amount of the reactive binder composition plus the amount of the to-be-bonded material, wherein the amount of the polyisocyanate and the polyol is such that the index is 150-10000, characterized in that the polyol is a polyol having an average equivalent weight of 100-2500 and an oxyethylene content of at least 50% by weight. The reactive composite is claimed as well together with composites obtained from this process and from these reactive composites.

Abstract: A process for preparing a polyisocyanurate polyurethane material, which process comprises reacting a polyisocyanate and an isocyanate-reactive composition, wherein the reaction is conducted at an isocyanate index of 1600 to 100,000 and in the presence of a trimerisation catalyst, wherein the polyisocyanate comprises a) 75-100% by weight of diphenylmethane di-isocyanate comprising at least 40%, preferably at least 60% and most preferably at least 85% by weight of 4,4?-diphenylmethane diisocyanate and/or a variant of said diphenylmethane diisocyanate which variant is liquid at 25° C.