| 摘要 |
PURPOSE: To prevent rupture due to internal pressure rise caused by vapor generated from an item to be heated when the item is heated by a microwave heater or the like without applying a special treatment beforehand. CONSTITUTION: In a packaging bag which is formed so as to store an item in a sealed condition using a film 1 made of a synthetic resin, a thermally bonded part H is formed by thermally bonding film parts I for forming an inner space, each of the parts facing a space S in the bag, so that tensile forces are exerted on the parts I as the pressure in the space S increases, whereby the periphery of the part H or the vicinity thereof can be broken and opened by tensile forces caused by the internal pressure. |
