| 摘要 |
[Problem] To provide a heat-shrinkable polyester-based film that has sufficient heat shrinkability in the main shrinkage direction, which is the longitudinal direction, and has a low degree of heat shrinkage in the width direction, i.e., the direction perpendicular to the main shrinkage direction, and that has few flaws in the film surfaces, low shrinkage stress, high mechanical strength, a small difference in molecular orientation angle, and reduced unevenness in thickness. [Solution] A heat-shrinkable polyester-based film which comprises ethylene terephthalate as the main constituent units and contains monomer units capable of being an amorphous moiety, in an amount of 5 mol% or less relative to all the units constituting the polyester resin and in which the main shrinkage direction of the film is the longitudinal direction. The heat shrinkabilities thereof in the longitudinal direction and width direction and the molecular orientation angle difference that is the difference between the molecular orientation angle in an area near one width-direction edge and the molecular orientation angle in an area near the other width-direction edge are respectively within specific ranges. |
