| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented polyester film which is adapted for a medical radiographic film, capable of adopting a heat-developing system which enables rapid processing and ensuring hue and dimensional stability level similar to those by wet development and simultaneously satisfies low heat shrinkage, low curling, high transparency and work efficiency in wind rolling and conveyance. SOLUTION: When the biaxially oriented polyester film for a heat sensitive color forming material is heat-treated at 120 deg.C for 20 sec, heat shrinkage simultaneously satisfies the following expressions (1) and (2), color difference simultaneously satisfies the following expressions (3)-(5) and the extent of curl satisfies the following expression (6). (1) 0.001<=SMD<=0.1 (2), -0.1<=STD<=0.1, (3) 60<=L<=80, (4) -10<=a<=0, (5) -30<=b<=-20, (6) -2<=(the amount of curl)<=+2 (mm) (where SMD is the heat shrinkage (%) of the film in the longitudinal directioning, STD is the heat shrinkage (%) of the film in the transverse direction, L, a and b are values of L*a*b* color space display system, measured with a color- difference meter and the extent of curl is curvature from the plane of the film).
|
