Teijin Limited

Mitsuru Teramoto

Kenji Suzuki

Shinya Watanabe

Koji Furuya

Ryoji Tsukamoto

Masahiko Kosuge

Seiji Ito

Shinichi Kawai

Manabu Kimura

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 bis[4-(.omega.-hydroxyalkoxy)phenyl]sulfone and 0 to 3 mol % of a glycol other than ethylene glycol and bis[4-(.omega.-hydroxyalkoxy)phenyl]sulfone 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.degree. C. and showing an endothermic energy of 0.3 mJ/mg or more.

Base film for photographic films

Biaxially oriented film

Biaxially oriented polyethylene naphthalate copolymer film

A process for producing an aromatic polyester by esterifying a dicarboxylic acid mainly composed of an aromatic dicarboxylic acid and a glycol mainly composed of ethylene glycol in the presence of 1 to 30 mmol %, based on the dicarboxylic acid, of a quaternary phosphonium sulfonate having ester-forming functional group(s), and then polycondensing the resulting product.

Process for producing aromatic polyester

Growing community of inventors

Matsuyama, Japan

Mitsuru Teramoto