| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject film capable of expressing an excellent Young's modulus, an excellent strength, excellent thermal contraction, good orientability, etc., and useful in the fields of magnetic recording media, photographic films, printing films, etc., by orienting a non-oriented film containing polyethylene terephthalate having a specific density as a main component. SOLUTION: This polyethylene terephthalate film is obtained by orienting (A) a non-oriented film [e.g. a film having a constant pressure specific heat of 330-360 J/(K.mol) at 360K] containing polyethylene terephthalate as a main component and having a density of 1.2-1.335 at 25 deg.C under a condition of 1 atm in a longitudinal direction or in a width direction. The film is preferably obtained by orienting the component A at an orientation temperature of [glass transition temperature (Tg)-50] deg.C to (Tg-100) deg.C in the prescribed direction in one stage or in multi-stages so as to give a total orientation ratio of 3-15 times and subsequently orienting the film in a direction rectangular to the first direction in one stage or in multi-stages so as to give the total orientation ratio of 3-15 times. |
