| 摘要 |
[Problem] To provide a polyester film suitable for obtaining a vapor-deposited film having exceptional oxygen and water vapor gas barrier properties, and a vapor-deposited film using the same. [Solution] A 5- to 20-μm-thick biaxially oriented polyester film, wherein the polyester film is configured such that the following requirements (1)-(4) satisfy specific ranges. (1) Difference (Nx-Ny) between refractive index (Nx) in the lengthwise direction and refractive index (Ny) in the widthwise direction, along the entire film width; (2) heat shrinkage in the lengthwise direction and widthwise direction when film is heat-treated for 30 minutes at 150°C, along the entire film width; (3) change in orientation angle relative to film-widthwise direction; (4) change in difference in heat shrinkage in +45° direction and -45° direction, taking the clockwise direction as the positive direction, relative to the lengthwise direction when heat film is treated for 30 minutes at 150°C, relative to film-widthwise direction. |
