Biaxially oriented film

摘要

PCT No. PCT/JP98/04871 Sec. 371 Date Jun. 28, 1999 Sec. 102(e) Date Jun. 28, 1999 PCT Filed Oct. 28, 1998 PCT Pub. No. WO99/21912 PCT Pub. Date May 6, 1999A biaxially oriented film (1) which is substantially formed from a polyethylene naphthalate copolymer comprising ethylene-2,6-naphthalate units in an amount of 90 to 99.9 mol % based on the total of all recurring units and an isophthalic acid component or a decalin-2,6-dicarboxylic acid component in an amount of 0.1 to 10 mol % based on the total of all dicarboxylic acid components and which has (2) Young's modulus of 500 kg/mm2 or more in each of a longitudinal direction and a transverse direction, (3) a plane orientation coefficient of 0.230 to 0.275 and (4) a density of 1.350 g/cm3 or more.