| 摘要 |
<p>A biaxially oriented polyester film for a high-density magnetic recording medium, particularly a high-density magnetic recoding medium of linear recording system, which has high strength in longitudinal and transverse directions, excellent dimensional stability in a crosswise direction and is flat and excellent in output characteristics and a process for producing the same. The biaxially oriented film is made from polyethylene-2,6-naphthalate and has a Young's modulus in a longitudinal direction of 8 GPa or more, a Young's modulus in a transverse direction of 6 GPa or more, a temperature expansion coefficient in the transverse direction ( alpha t) of - 5 x 10<-6>/ DEG C to +12 x 10<-6>/ DEG C, a humidity expansion coefficient in the transverse direction ( alpha h) of 5 x 10<-6>/%RH to 12 x 10<-6>/%RH and a thermal shrinkage factor in the transverse direction at 105 DEG C of -0.5 to +1.5 %</p> |
