Patent ID: 10035335

Abstract:
The invention provides a heat shrinkable polyester film which has (1) a hot-water heat shrinkage of not less than 55% and not more than 90% in a main shrinking direction of the film when dipped in hot water at 98° C.; (2) a hot-water heat shrinkage of not less than −5% and not more than 12% in a direction orthogonal to the main shrinking direction of the film when dipped in hot water at 98° C.; (3) a difference in specific heat capacity ΔCp between at a lower and a higher temperature than Tg of not less than 0.1 J/(g·° C.) and not more than 0.7 J/(g·° C.) when a reverse heat flow is measured with a temperature modulated DSC; and (4) a tensile breaking strength of not less than 70 MPa and not more than 150 MPa in the direction orthogonal to the main shrinking direction of the film.