| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyester having a low refractive index and excellent thermal stability, and to provide a film which is obtained by using the polyester produced by the method and has a low photoelastic coefficient and excellent light reflection properties. SOLUTION: The method for producing a polyester is provided in which a polyester is produced by performing a transesterification reaction of a dicarboxylic acid component containing an alicyclic dicarboxylic acid and a diol component and then performing a polycondensation reaction. In the method, the transesterification reaction is performed in the presence of an alkali metal compound (A), and after the transesterification reaction, an alicyclic diol, a phosphorus compound (B), and a titanium compound (C) are added in succession, and then the polycondensation reaction is performed, wherein, the glass transition temperature measured by differential scanning calorimetry is 65-90°C, the refractive index with sodium D-line is 1,500-1,570, the gelation rate is≤10%, the content of metal element of the (A) is 5-200 ppm, the content of metal element of the (B) is 10-300 ppm, and the content of metal element of the (C) is 3-100 ppm. COPYRIGHT: (C)2011,JPO&INPIT
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