PURPOSE: To provide the polyurethane having a specific softening point, excellent thermal properties and useful for abrasives or the like, formed by incorporating a crosslinked polyurethane containing an isocyanurate structure or the like by allowing an isocyanate-terminated polymer to react with a hydroxyl- containing organic compound under a specific condition.

CONSTITUTION: The object polyurethane having a softening point of ≥65°C is synthesized by forming a crosslinked polyurethane having an isocyanurate and/or oxazolidone structure, allowing an isocyanate-terminated polymer react with a hydroxyl-containing organic compound to in the presence of a curing agent such as a tertiary amine or the like arranging the ratio of -NCO/-OH to be ≥1.5, preferably ≥4.5. Abrasives wheel made of composite materials are obtained by adhering abrasive particles to fibers of fibrous substrate utilizing the polyurethane.