| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester which shows little dimensional changes in the width direction although the film is formed thin and has high mechanical strength, and which shows good adhesion property with a magnetic layer because delamination on the film surface is hardly caused, which has high output characteristics, little error rate and good characteristics as a magnetic recording medium as a final product, especially as a digital videotape. SOLUTION: The biaxially oriented polyethylene-2,6-naphthalate film for a magnetic recording medium has the following properties. The film has <7μm thickness, >=850 kg/mm<2> Young's modulus in the longitudinal direction, >=550 kg/mm<2> Young's modulus in the width direction, <=0.01 % thermal shrinkage when the film is kept at 65 deg.C for 9 days without load, and >=1.485 refractive index in the thickness direction. |
