Patent ID: 8785570

Claim:
A method for preparing a solid moulded polyisocyanurate polyurethane material having a density of more than 100 kg/m 3 without the use of a blowing agent, the method comprising: (a) dispensing (i) a polyisocyanate, (ii) an isocyanate-reactive composition, and (iii) a trimerisation catalyst into a mould; (b) reacting the polyisocyanate and the isocyanate-reactive composition at an isocyanate index of 1600 to 100,000 in the presence of the trimerisation catalyst to form the solid polyisocyanurate polyurethane material; and (c) removing the solid polyisocyanurate polyurethane material from the mould, wherein said polyisocyanate comprises: polyisocyanate (a), which comprises 75-100% by weight of diphenylmethane diisocyanate, at least 40% by weight of said diphenylmethane diisocyanate comprising 4,4′-diphenylmethane diisocyanate, or a variant of diphenylmethane diisocyanate that is liquid at 25° C. and has an NCO value of at least 20% by weight, or both, and polyisocyanate (b), which comprises 25-0% by weight of another polyisocyanate, the amount of polyisocyanate (a) and polyisocyanate (b) calculated on the total amount of this polyisocyanate (a) and polyisocyanate (b); and wherein said isocyanate-reactive composition consisting of 80-100% by weight of a polyether polyol and 20-0% by weight of one or more other isocyanate reactive compounds, said polyether polyol having an average nominal functionality of 2-6, an average equivalent weight of 1100-5000, and an oxyethylene (EO) content of 65-100% by weight, the amount of the polyether polyol and the one or more other isocyanate reactive compounds being calculated on the total amount of this polyether polyol and the other isocyanate reactive compound, and wherein the hardblock content of the polyisocyanurate polyurethane material is at least 50%; and wherein when the one or more other isocyanate reactive compounds is present, the one or more other isocyanate reactive compounds consists of a chain extender, a cross-linker, a polyether polyamine, and a polyol different from the polyether polyol.