| 摘要 |
PROBLEM TO BE SOLVED: To obtain a thermoplastic elastomer excellent in light resistance as well as mechanical strengths and transparency by addition-polymerizing an aliphatic or alicyclic diisocyanate with a high-molecular-weight diol having a specified average molecular weight and an alicyclic diol. SOLUTION: Used are a high-molecular-weight diol having an average molecular weight of 500-5,000 and an alicyclic diol of formula I or II. In the formulae, X is methylene, isopropylidene, sulfone, ketone, or an ether; R1 and R2 are each a 2-4C alkylene; and m and n are positive integers satisfying 0<=m+n<=4. It is desirable that the ratio of the polymer diol to the alicyclic diol is 1/2 to 1/10 by mole, and that the ratio of the total of the polymer diol and the alicyclic diol to the diisocyanate is 1/0.9 to 1/1.2 by mole. A desirable example of the reaction consists of previously reacting the diisocyanate with the high- molecular-weight diol, adding the alicyclic diol to the reaction mixture, and reacting the entire mixture.
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