Heat-shrinkable polyester film and process for producing the same

摘要

[Problems] A heat-shrinkable polyester film is provided which exhibits a high shrinkability in a high-temperature range with a main shrinking direction oriented in a longitudinal direction thereof, though not shrinking in the longitudinal direction in a low-temperature range, possesses an extremely high mechanical strength in a transverse direction orthogonal to the main shrinking direction, and in particular, can be utilized suitably as a film for forming a jacket label of a battery or similar applications. [Means for solution] A heat-shrinkable polyester film according to the present invention has a main shrinking direction oriented in a longitudinal direction thereof. A ratio of hot-water thermal shrinkage in the longitudinal direction responsive to treatment in hot water at 80°C for 10 seconds, and ratios of thermal shrinkage in the longitudinal direction and thermal shrinkage in the transverse direction responsive to treatment in a glycerin bath at 140°C for 10 seconds are adjusted so as to fall within predetermined ranges, respectively. [Chosen drawing] None