| 摘要 |
PROBLEM TO BE SOLVED: To enable the dimensional stability and long-term storage stability of a magnetic recording medium by setting the ratio Ym1/Ym20 of the Young's modulus Ym1 measured at a specific initial strain speed and the Young's modulus Ym20 measured at other specific initial strain speed to a specific range. SOLUTION: The ratio of Ym1/Ym20 of the Young's modulus Ym1 measured at an initial strain speed of 0.1 mm/mm.min and the Young's modulus Ym20 measured at an initial strain speed of 2 mm/mm.min is 0.85-1.1 in both of the longitudinal and lateral directions of a film. The creep compliance of the film after the elapse of 30 min under a condition of temp. 50 deg.C and load 28 MPa is 1.11-0.35 GPa-1 in both of the longitudinal and lateral directions of the film. The heat shrinkage factor in the lateral direction of the film at 100 deg.C for 30 min is below 0.3%. From these test results, the film is pref. from a viewpoint of heat resistance, chemical resistance, durability or the like.
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