| 摘要 |
PURPOSE:To obtain a composition, consisting of a polyester derived from specific components, having excellent mechanical properties in the thickness direction and capable of providing a packaging bag having excellent crispy feeling and handleability without causing cleavage, delamination, cracking, etc. CONSTITUTION:A film consisting of a polyester film, derived by reacting a bifunctional carboxylic acid consisting essentially of a diphenyldicarboxylic acid and/or an ester-forming derivative thereof with a dihydroxy compound and/or an ester-forming derivative thereof and having <=0.10, preferably <=0.05 ultimate birefringence value. A diphenyldicarboxylic acid selected from diphenyl-2,2'-dicarboxylic acid, diphenyl-2,3'-dicarboxylic acid and diphenyl-3,3'- dicarboxylic acid is used as the diphenyldicarboxylic acid. |
