| 摘要 |
PURPOSE:To provide the subject product composed of a polyester produced by reacting a specific crystalline polyester with a diisocyanate under specific condition, having a molecular weight sufficiently high for practical purpose and exhibiting excellent thermal stability, tensile strength, drawability, etc. CONSTITUTION:A polyester of formula having a number-average molecular weight of >=10,000 and containing >=2 urethane bonds is produced by reacting (A) 100 pts.wt. of a crystalline polyester having a number-average molecular weight of >=5,000 and derived from 1,4-butanediol and succinic acid with (B) 0.1-5 pts.wt. of a diisocyanate (preferably hexamethylene diisocyanate) at a temperature higher than the melting point of the component A in molten state. The polyester is formed by inflation process, T-dice process, etc., to obtain the objective film. The amount of 1,4-butanediol constituting the component A is preferably 1.05-1.2 mol based on 1 mol of the succinic acid. |
