| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film excellent in heat resistance.SOLUTION: Provided is a biaxially oriented polyester film in which the amount of terminal carboxyl groups is 20 eq./ton or lower, and, provided that the inherent viscosity of a polyester resin composing the film is defined as IVa and the inherent viscosity of the polyester resin composing the film after the film is subjected to heat treatment at 200°C0%RH for 24 hr is defined as IVb, the biaxially oriented polyester film satisfies the following (i) and (ii): (i) 0.65≤IVa≤0.90 and (ii) 0≤IVb-IVa≤0.3.SELECTED DRAWING: None |
