| 摘要 |
PROBLEM TO BE SOLVED: To provide a packaging bag capable of suppressing generation of wrinkles on the upper edge of the packaging bag. SOLUTION: The main body part 10 of the packaging bag is constituted by a bottom face sheet and a pair of side face sheets. The bottom face sheet and a pair of the side face sheets are heat-welded at a bottom edge bonding part 13. For a pair of side face sheets, their side edges are heat-welded to each other at side edge bonding parts 14. In addition, a pair of the side face sheets are heat-welded at projecting bonding parts 16 projecting so as to form a semi-circular shape toward the central side of the main body part 10 from the side edge bonding parts 14 in the width direction of the main body part 10. The projection lengths X of these projecting bonding parts 16 are formed so as to occupy 1/15-1/5 of the width Y of the main body part 10 (the side face sheet). The formed positions of the projecting bonding parts 16 are determined so that the length Z from the largest parts of the lengths of the projections of the projecting bonding parts 16 to the lower end of the main body part 10 is 1/3-1/2 of the height T of the main body part 10. COPYRIGHT: (C)2009,JPO&INPIT
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