| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyurethane excellent in elastic recovery by using a high-mol.-wt. polyol, an org. diisocyanate, and a mixture of specific structural isomers having arom. rings as a chain extender. SOLUTION: In producing a polyurethane from a high-mol.-wt. polyol, an org. diisocyanate, and a chain extender, a mixture of at leas two structural isomers selected from among structural isomers represented by formulas I to III (wherein X and Y are each a group represented by formula IV; ZH is a hydroxyl or amino group having an active hydrogen atom, 1<m<4; 0<n<4; and A, B, C, and D are each H, 4C or lower alkyl, or halogen) is used as the extender. Its examples are a mixture of 1,4-, 1,3-, and 1,2-bis(β-hydroxyethoxy) benzenes and a mixture of 1,4-, 1,3-, and 1,2-bis(β-aminoethoxy)benzenes. In order to obtain a better elastic recovery the mixing ratio is pref. represented by formula V (wherein X1 to X3 are molar percentages of structural isomers represented by formulas I to III, respectively, based on the extender).
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