Patent ID: 7939174

Claim:
A film roll of a heat-shrinkable polyester film, the length of the film roll ranging from 1000 m to 6000 m, and the heat-shrinkable polyester film meeting the following requirements (1), (2) and (3): (1) when an initiation end of winding of a film, which is obtained from a steady region where physical properties of the film are stabilized in a longitudinal direction, is designated as a first end; a termination end of winding thereof is designated as a second end; a first cut-off point of samples of the film is provided at a position 2 m or less inner from the second end, a final cut-off point of the samples is provided at a position 2 m or less inner from the first end; a plurality of additional sample cut-off points are provided at an interval of about 100 m from the first cut-off point, the samples being square samples in a size of 10 cm×10 cm cut off from each of the cut-off points; and all the samples have a heat shrinkage percentage of 20% or more in the maximum shrinkage direction after the respective samples are immersed in hot water at 85° C. for 10 seconds, subsequently in water at 25° C. for 10 seconds, and then withdrawn; (2) when a raw polymer used for production of the film comprises a major constitutional unit and one or more sub constitutional units different therefrom; the sub constitutional unit which is present in the greatest amount among all the sub constitutional units is designated as a primary sub constitutional unit; the content of the primary sub constitutional unit in the each sample properly cut off from each of the cut-off points described in the requirement (1) is 7 mole % or more in 100 mole % of all the constitutional units; and when an average of the content of the primary sub constitutional unit is calculated, the contents thereof of all the samples fall within a range of ±2 mole % relative to the average content, wherein the major constitutional unit is an ethylene terephthalate unit, and the primary sub constitutional unit is a unit consisting of neopentyl glycol and terephthalic acid, or a unit consisting of 1,4-butanediol and terephthalic acid, or a unit consisting of 1,4-cyclohexane dimethanol and terephthalic acid, or a unit consisting of ethylene glycol and isophthalic acid; and (3) when an average of the heat shrinkage percentages in the maximum shrinkage direction of the samples defined in the requirement (1) is calculated, the heat shrinkage percentages of all the samples fall within a range of ±3% relative to the average.