Аннотация:The process of bulk copolycyclotrimerization of 1,6-hexamethylenediisocyanate with 1-chlorohexamethylene-6-isocyanate catalyzed by hexa-n-butyldistannum oxide at 353 K was studied by microcalorimetry and GPC. It was established that the reaction obeys the first order kinetic law, and that monomers and trimers are present in the reaction system to the completion of the reaction. Isocyanate groups of comonomers have equal reactivity. The composition of oligoisocyanurates was determined as a function of initial concentration of monoisocyanate. MWD of mixed-composition oligoisocyanurates was found. It was shown experimentally that there exists an initial ratio of isocyanate concentration in the reaction system at which gelation does not occur.