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.,
1
wherein R
1
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,
H—A—R
2
—A—H (2)
wherein R
2
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.
根据本发明的具有噁二嗪环的末端封端
异氰酸酯预聚物,其特征在于 NCO 端
异氰酸酯预聚物的至少一个
异氰酸酯基团被末端封端剂(C)封端,该 NCO 端
异氰酸酯预聚物的末端具有 NCO 基团,并包括由下式(1)表示的噁二嗪三酮化合物(A)衍生的单元和由下式(2)表示的活性氢化合物(B)衍生的单元、用一种末端封端剂(C)衍生的单元封端,该单元在一个分子中至少有一个活性氢,并且末端封端的
异氰酸酯预聚物的软化点不低于 50 摄氏度。,
1
其中 R
1
是选自由 2 至 20 个碳原子的脂族烃基、具有芳香族基团的脂族烃基和脂
环烃基组成的组,且 n 是 1 或更大的整数、
H-A-R
2
-A-H (2)
其中 R
2
是 2 至 12 个碳原子的直链、支链或环状亚烷基,A 是氧原子、
硫原子、N-R′基团(R′是氢原子、烷基、芳基或芳烷基)和 COO 基团中的任一种。