Abstract: Provided is a heat-shrinkable polyester film which undergoes less change in the physical properties even in a high-humidity environment, has excellent storage stability, and effectively suppresses a breakage phenomenon of the film after heat shrinkage. Disclosed is a heat-shrinkable polyester film derived from a polyester resin, in which when tensile strengths in a main shrinkage direction obtained before and after immersion in water at 23° C. for 168 hours in a tensile test as measured according to JIS K 7127 are designated as C1 (MPa) and C2 (MPa), the following Relational Expression (1) is satisfied: ?5.3<(C2?C1)<4.

Abstract: A heat-shrinkable polyester film that effectively suppresses a breakage phenomenon is provided. Disclosed is a heat-shrinkable polyester film derived from a polyester resin, the heat-shrinkable polyester film satisfying the following configurations (a) to (c): (a) a thermal shrinkage ratio in the TD direction obtainable under the conditions of 10 seconds in hot water at 80° C. as designated A1 is a value of 25% or greater; (b) when a thermal shrinkage ratio in the TD direction obtainable under the conditions of 10 seconds in hot water at 90° C. as designated A2 is a value of 40% or greater; and (c) when the upper yield point stress is E1 and the lower yield point stress is E2, a numerical value represented by E1?E2 is a value of 5 MPa or less.

Abstract: A heat-shrinkable polyester film having excellent wrinkle resistance characteristics is provided. A heat-shrinkable polyester film satisfying the following configurations (a) to (c): (a) a thermal shrinkage ratio in the TD direction obtainable under the conditions of 10 seconds in hot water at 90° C. as designated as A2, is a value of 53% or greater; (b) a maximum shrinkage stress in the TD direction at 90° C. as designated as B is a value of 2 to 10 MPa; and (c) a value represented by B/A2 is a value of 0.08 to 0.15 MPa/%.

Abstract: Provided is a polyester-based shrink film having excellent predetermined impact resistance and having a uniform shrinkage ratio near the shrinking temperature. Disclosed is a polyester-based shrink film that satisfies the following configurations (a) to (c): (a) the impact resistance strength before shrinking as measured by a film impact tester is designated as A1, and this is within 20 to 60 J/mm; (b) when the impact resistance strength measured by a film impact tester after having been shrunk by 10% in hot water at 80° C. is designated as A2, the numerical value represented by A2/A1×100 is within 60% to 110%; and (c) when the shrinkage ratio under the conditions of 80° C. and 10 seconds is designated as B1, and the shrinkage ratio under the conditions of 90° C. and 10 seconds is designated as B2, the numerical value represented by B1/B2×100 is within 70% to 90%.