| 摘要 |
PURPOSE: To facilitate the longitudinal cutting while obtaining the lateral strength and to improve the characteristics of a final product of digital video tape by specifying the thickness of a film, the Young's modulus of the lateral direction of the film and the tear propagating velocity of the longitudinal direction of the film. CONSTITUTION: Regarding biaxially oriented polyester film, the thickness of the film is specified to 8μm or less, the Young's modulus of the lateral direction (TD) of the film is specified to 800kg/mm<2> or more, and the tear propagating velocity of the longitudinal direction (MD) of the film is specified to 50-300g/mm. Two or more layers of the films are laminated, inactive particles are contained in the outermost layer of one side, the mean particle size of the particles is specified to 0.2μm or less, and the thickness of the outermost layer is specified to 0.1μm or less. Further, the quantity of germanium contained in the film is specified to the range of 0.005-0.03wt.% of the polymer. When pancake manufactured in this manner is observed from the direction (1), slitting properties can be improved like a sample 3 as compared with a sample 2. |
