FLEXIBLE PACKAGE

摘要

A flexible package having improved shape-retaining property and self-standing property is provided. In the flexible package, at least a first side-surface film and a second side-surface film are joined together, and peripheral portions of the films are sealed to form a storage part. On one or both of two side edge portions which are sealed regions of the peripheral portions at both side ends of the first side-surface film and the second side-surface film, a non-sealed region is provided which is a region in which the first side-surface film and the second side-surface film are not sealed over a predetermined length. The non-sealed region is surrounded by the sealed regions of the first side-surface film and the second side-surface film. In the non-sealed region, a gas injection portion is formed in which a gas whose specific heat at constant volume is 0.67 kJ/kg·deg or higher at 0°C and 1 atm. The gas injection portion has a diameter not smaller than 3 mm but not larger than 50 mm. A repelling force measured when the entirety of the gas injection portion is nipped from the first side-surface film side and the second side-surface film side and squeezed until the width of the nipped gas injection portion becomes half the diameter of the gas injection portion, is not smaller than 4 N but not larger than 30 N at 23°C and 1 atm.