Zippered bag and method of forming the same

摘要

A gusset bag for packing a content comprises a bag body having a tubular structure and composed of a pair of opposing flat portions constituting front and back surface portions and two side surface portions connecting the front and back surface portions at both side edges thereof and having lines folded inward which extend along longitudinal direction of the side surface portions and along which the side surface portions are folded inward. A zipper element is mounted on inner surfaces of the flat portions at portions near the end opening of the bag body. A fused seal portion formed to and near the end opening portion of the bag body to seal the end opening portion, the fused seal portion including an end seal portion extending along an entire length of the end opening and side seal portions extending from both ends of the end seal portion along the side edges of the flat portions. The side seal portions extend beyond the portions on which the zipper element is mounted. The sealing process is carried out integrally with portions of the side surface portions, which are once inwardly folded along the folding lines and then drawn out and folded outward from the end opening of the bag body. The zipper element is mounted to the portions near the end opening between the end opening and the once folded and then drawn out side surface portions.