| 摘要 |
PROBLEM TO BE SOLVED: To provide a plasticizer for a urethane sealing material having an isocyanate group at a molecular chain terminal, good in plasticity, and giving little heat loss and migration, by using a urethane polyether. SOLUTION: This urethane polyether is represented by the formula (wherein R1 is a residual group of an m-valent isocyanate whose isocyanate group is removed; R2 and R3 are each a hydrocarbon group; and (m) and (n) are each a positive integer) and its mol.wt. is pref. 300-30,000, and residual amount of isocyanate group is pref. 0.5-5 wt.%. Manufacturing method is not specifically restricted, but an alkylene oxide is attached in the presence of a catalyst such as sodium hydroxide to alcohol or phenol to be a base of polyalkylene glycol monoether, as a precursor. An m-valent isocyanate is reacted with the obtd. polyalkylene glycol monoether without a catalyst or in the presence of a urethanization catalyst. Compounding amount of a plasticizer is 1-100 wt.% to a sealing substrate.
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