| 摘要 |
PCT No. PCT/JP98/02002 Sec. 371 Date Jan. 5, 1999 Sec. 102(e) Date Jan. 5, 1999 PCT Filed May 1, 1998 PCT Pub. No. WO98/50456 PCT Pub. Date Nov. 12, 1998A biaxially oriented film which is made substantially of (1) a polyethylene naphthalate copolymer comprising an ethylene naphthalate unit in an amount of 92 to 99.5 mol % based on all recurring units and at least one copolymer component selected from the group consisting of (a) a glycol having a fluorene skeleton in the molecule, (b) p-hydroxymethylbenzoic acid, (c) p-hydroxyethoxybenzoic acid and (d) p-hydroxyethoxyethoxybenzoic acid in an amount of 0.5 to 8 mol % based on the total of all dicarboxylic acid components, and which has (2) Young's moduli in both longitudinal and transverse directions of 500 kg/mm2 or more and (3) a delamination resistance of 10% or less in terms of fold line whitening ratio. Since this biaxially oriented film of the present invention is excellent in delamination resistance, curling resistance, mechanical strength, color and transparency, it is of great value as a base film for a photo film.
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