THIN PACKAGING BAG AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a packaging bag which is thin and excellent in barrier function, and to provide a method for manufacturing the same. SOLUTION: The packaging film 10 is formed by making a substrate layer A 11 and a substrate layer B 12 overlie each other. The substrate layer A 11 has a first surface forming an external surface of the packaging bag and a second surface opposite to the same. The substrate layer B 12 has a first layer forming an internal surface of the packaging bag and a second layer opposite to the same. The second surface of the substrate layer A 11 or the second surface of the substrate layer B 12 has formed thereon an evaporated layer 15 made of a metal or a metallic oxide. Further the substrate layer A 11 and the substrate layer B 12 include drawn polypropylene homopolymer layers 11, 13, respectively, and at least the substrate layer B 12 includes a thermal fusion layer 14 having a thickness of 5μm or less and a fusion point of 150°C or less, on one side thereof close to the first surface, in addition to the drawn polypropylene homopolymer film layer 13. Furthermore the substrate layer B 12 has a stiffness of 5(GPa)2or less, and exerts a pressure larger than that of the other portion with respect to an easily leakable portion when the packaging film is transversely sealed. COPYRIGHT: (C)2008,JPO&INPIT