| 摘要 |
PROBLEM TO BE SOLVED: To prevent an air barrel for a structure suitable especially for a simple bathtub, which is not deviated inside an outer bag in spite of folding and does not generate air leakage due to a crack or a fracture in spite of joining a bent part to an inner bag through the use of a fusing means at the time of bending the inner bag. SOLUTION: The inner bag is provided with a seal part 16 made by laminate- hitting fusing parallel with upper and lower edges and at a position at a prescribed distance from the edge end of both right/left edges, a seal part 17 made by lapping both tips hitting fusing is formed along each edge. Then the corner part on an upper side corresponding to the corner parts of an outer bag formed in a corner cut shape are respectively folded in a corner cut shape to form a first folded part 11. Both right and left edges are folded along each edge by a width larger than a distance between the edge tip and the seal part to form a second folded part 12 and the air non-injecting parts of the first/second folded parts 11 and 12 are engaged with each other. |
