| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyethylene terephthalate resin film suitable for the base film of a laminate. SOLUTION: In the polyethylene terephthalate resin film, the differenceΔn<SB>ab</SB>between the refractive indices in the directions forming angles of 45°and 90°respectively with the longitudinal direction of the film is 0.015-0.060. The film satisfies the following requirements: (1) the film, the warpage heights of the four corners of a specimen of 300 mm long in the longitudinal direction and 210 mm wide in the width direction do not exceed the thickness of the film, (2) when the specimen is heat-treated at 150°C for 30 min, the average warpage height of the four corners is 0.5-5.0 mm, and (3) all the ratios TS/TE (strength at break/elongation at break) in four directions are 0.6-2.6 (MPa/%). COPYRIGHT: (C)2010,JPO&INPIT |
