| abstract |
A biaxially oriented film (1) which is substantiallynformed from a polyethylene naphthalate copolymer comprisingnethylene-2,6-naphthalate units in an amount of 90 to 99.9nmol% based on the total of all recurring units and annisophthalic acid component or a decalin-2,6-dicarboxylicnacid component in an amount of 0.1 to 10 mol% based on thentotal of all dicarboxylic acid components and which has (2)nYoung's modulus of 500 kg/mm 2 or more in each of a longitudinalndirection and a transverse direction, (3) a plane orientationncoefficient of 0.230 to 0.275 and (4) a density of 1,350 g/cm 3 nor more. |