Terminal-blocked isocyanate prepolymer having oxadiazine ring, process for producing the same, and composition for surface-coating material

摘要

The end-blocked isocyanate prepolymer having an oxadiazine ring according to the present invention is characterized in that at least one of isocyanate groups of a NCO-terminated isocyanate prepolymer, which has NCO groups at the ends and comprises units derived from an oxadiazinetrione compound (A) represented by the following formula (1) and units derived from an active hydrogen compound (B) represented by the following formula (2), is blocked with a unit derived from an end-blocking agent (C) having at least one active hydrogen in one molecule, and that the end-blocked isocyanate prepolymer has a softening point of not lower than 50° C., ;wherein R₁ is a group selected from the group consisting of an aliphatic hydrocarbon group of 2 to 20 carbon atoms, an aliphatic hydrocarbon group having an aromatic group and an alicyclic hydrocarbon group, and n is an integer of 1 or greater,; $PTEXTPDATH\—A\—R/PDATHILSBPDAT2/PDAT/SB/HILPDAT\—A\—H\ \ (2)\; /PDAT/PTEXT$ ;wherein R₂ is a straight-chain, branched or cyclic alkylene group of 2 to 12 carbon atoms, and A is any one of an oxygen atom, a sulfur atom, a N—R′ group (R′ is a hydrogen atom, an alkyl group, an aryl group or an aralkyl group) and a COO group.