Base film for photographic films

摘要

A base film for photographic films formed from a copolyester comprising 97 to 100 mol% of 2,6-naphthalenedicarboxylic acid and 0 to 3 mol% of a dicarboxylic acid other than 2,6-naphthalenedicarboxylic acid and (i) 87 to 99.8 mol% of ethylene glycol, 0.2 to 10 mol% of bisÄ4-( omega -hydroxyalkoxy)phenylÜsulfone and 0 to 3 mol% of a glycol other than ethylene glycol and bisÄ4-( omega -hydroxyalkoxy)phenylÜsulfone or (ii) 97 to 100 mol% of ethylene glycol, 0 to 3 mol% of a diol other than ethylene glycol and 1 to 7 mol% of an oxycarboxylic acid. This base film has an endothermic peak having a peak top temperature, measured by a differential scanning calorimeter, of 120 to 160 DEG C and showing an endothermic energy of 0.3 mJ/mg or more.