PROBLEM TO BE SOLVED: To provide an underpants type disposable diaper in which a joining part of both ends of a front body and a rear body has a strong joining strength when the diaper are worn and is easily broken at the disposal of the diaper.SOLUTION: An underpants type disposable diaper is based on a finding that a joining strength of a lower part joining region 42 with a smaller number of superposed sheet members can be improved and that a joining part is easily broken at the disposal of the diaper by forming a width of the lower part joining region 42 with the smaller number of the superposed sheet members to be wider than a width of an upper part joining region 41 with a larger number of superposed sheet members, in joining both ends of a front body and a rear body of a diaper, and by forming each of the upper part joining region 41 and the lower part joining region 42 of rows of a plurality of short line-shaped seal parts that extend in a horizontal direction of the diaper.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2016,JPO&INPIT【課題】前身頃と後身頃の両端を接合部が,おむつの着用時には強固な接合強度を有しており,おむつの廃棄時には簡単に破断させ易くなっているパンツ型の使い捨ておむつを提供する。【解決手段】おむつの前身頃と後身頃の両端を接合するにあたり,重ね合わされたシート部材の数が少ない下部接合領域42の幅を,重ね合わされたシート部材の数が多い上部接合領域44の幅よりも幅広に形成し,しかも,上部接合領域41と下部接合領域42のそれぞれを,おむつの左右方向に延びる短線状の複数のシール部の列によって形成することにより,重ね合わされたシート部材の数が少ない下部接合領域42の接合強度を向上させることができ,かつ,おむつの廃棄時には接合部を破断させ易くなるという知見に基づく。【選択図】図3
