| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyethylene naphthalate film useful for manufacturing a magnetic recording medium excellent in a dimensional stability, flatness and a handling property as well as an electromagnetic convertibility. SOLUTION: The heat shrinkage factor in all the direction in a film surface is 0.4% or less (105 deg.C, 30 min.), and the Young's modulus in all the direction is 570 kg/mm2 or more and the difference between the maximum and minimum is 100 kg/mm2 or less. The average roughness of the central line of the film surface is 2-10 nm, and the coefficient of static friction between the films is 0.55 or less. |
