Abstract: Purpose: A process for preparing a liquid organic isocyanate having a carbodiimide group and/or an uretonimine group, excellent in storage stability. Solution: In a process for preparing a modified polyisocyanate by carbodiimidizing an organic polyisocyanate in the presence of a phospholine-based catalyst, silicon dioxide particles having a specific surface area of at least 400 m2/g and an oil absorption of at least 180 ml/100 g are used to adsorb and inactivate the catalyst to thereby terminate the carbodiimidization reaction.

Abstract: Methods comprising: providing an aromatic polyisocyanate and a polyol; and reacting the aromatic polyisocyanate and the polyol in the presence of a blowing agent and a catalyst to form a rigid polyurethane foam; wherein the blowing agent comprises water and a hydrocarbon having 3 to 8 carbon atoms; and wherein the polyol comprises a mixture of two or more polyether polyols according to formula (1): wherein each R independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms and n represents an integer of 0 to 5; the mixture of polyether polyols having a mean functionality of 4.5 or more; and wherein the mixture of polyether polyols comprises 50 to 70% by weight of a compound of formula (1) wherein n=0 is and 30 to 50% by weight of a compound of formula (1) wherein n?1; and wherein the mixture of polyether polyols comprises 2.5% by weight or more a compound of formula (1) wherein n=4, all percentages by weight based on the mixture of polyether polyol.