| 摘要 |
PROBLEM TO BE SOLVED: To prepare a biaxially oriented polyester film having excellent dimensional stability in all of temperature and humidity ranges comprising a low temperature and low humidity range, a low temperature and high humidity range, a high temperature and low humidity range, and a high temperature and high humidity range, and especially useful as a high-density magnetic recording medium. SOLUTION: This biaxially oriented polyester film has a thermal expansion coefficient (a) (ppm/°C) in the transverse direction of the film, a moisture expansion coefficient (b) (ppm/%RH) in the transverse direction, and a temperature variation coefficient (c) (ppm/°C) of shrinkage in the transverse direction, when measured by applying a load of 10 MPa to the film in the longitudinal direction, so that the coefficients (a), (b), and (c) satisfy following inequalities: -3≤a≤15; 0≤b≤10; 0≤c≤15; a-2b-c≥-15; and a+2b-c≤30. COPYRIGHT: (C)2005,JPO&NCIPI
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