| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film for a photographic photosensitive material having a good superposing accuracy, excellent transparency, slipperiness and windability. SOLUTION: The biaxially oriented polyester film is thermally relaxed by a roll heating type to simultaneously satisfy a heat shrinkage factor when heat treated at 120 deg.C for 20 s of 0.001<=SMD<=0.1, -0.1<=STD<=0.1, -0.05<=S45<=0.05, -0.05<=S135<=0.05,|S45-S135|<=0.05 (wherein SMD is the heat shrinkage factor % of the longitudinal direction of the film, STD is the heat shrinkage factor % of the lateral direction of the film, S45, S135 are the heat shrinkage factors of 45 deg. direction and 135 deg. direction of the film when the film lateral direction is 0 deg., and the longitudinal direction is 90 deg.).
|
