Pants-type disposable diapers

Abstract

To provide a pants-type disposable diaper suppressing clinging to a wearer's skin when a wearer sweats.SOLUTION: A pants-type disposable diaper 1 comprises an absorbent body 5 including an absorbent core 40, and an outer wrapper 3 disposed on a non-skin-facing surface side of the absorbent body 5. A sheet constituting the outer wrapper 3 includes a folded sheet part 51 formed by being folded to a skin-facing surface side along a peripheral edge WE of a waist opening. The folded sheet part 51 and an end fixing sheet 34 have first free-part facing parts 73 where free parts in a non-fixed state exist facing each other in a longitudinal direction X, on a waist opening side with respect to an edge of the absorbent body 5 in the longitudinal direction X. The end fixing sheet 34 and the fixing sheet 35 have second free-part facing parts 83 where free parts in a non-fixed state exist facing each other in the longitudinal direction X, on a crotch part C side with respect to the edge of the absorbent main body 5 in the longitudinal direction X in the longitudinal direction X.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pants-type disposable diaper. [Background technology]

[0002] When a wearer sweats while wearing a disposable diaper, the sheet on the skin-facing side of the diaper may stick to the wearer's skin, causing stuffiness and making the diaper uncomfortable to wear. Therefore, there is a demand for disposable diapers that do not stick to the skin in this way.

[0003] For example, Patent Document 1 proposes an absorbent article comprising an absorbent main body and an exterior body, in which the front and rear ends of the exterior body are folded inward, an outwardly disposed fold portion and an inwardly disposed folded-back portion are stacked, and the inner end of the folded-back portion in the front-to-rear direction is not bonded to the fold portion, and the outer end of the absorbent main body in the front-to-rear direction is not bonded to the exterior body. According to this document, the inner end of the folded-back portion that is not bonded to the fold portion and the outer end of the absorbent main body in the front-to-rear direction that is not bonded to the exterior body protrude inward, thereby creating a space between the wearer and the exterior body and suppressing stuffiness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-128512 Summary of the Invention [Problem to be solved by the invention]

[0005] The absorbent article described in Patent Document 1 has an insufficient space between the wearer and the outer body, and there is room for improvement in the effect of suppressing stuffiness. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pants-type disposable diaper that is prevented from sticking to the wearer's skin when the wearer sweats. [Means for solving the problem]

[0006] The present invention relates to a pants-type disposable diaper having a ventral side portion arranged on the ventral side of a wearer, a dorsal side portion arranged on the dorsal side of the wearer, and a crotch portion located between the ventral side portion and the dorsal side portion, the diaper comprising an absorbent body having an absorbent core, and an outer body arranged on the non-skin-facing side of the absorbent body, the diaper having a vertical direction extending from the ventral side portion through the crotch portion to the dorsal side portion and a horizontal direction perpendicular to the vertical direction, and the diaper having a waist opening and a pair of leg openings. In one embodiment, it is preferable that the sheet constituting the outer body has a folded sheet portion formed by folding back along the peripheral edge of the waist opening toward the skin-facing side, an end fixing sheet arranged to cover the vertical ends of the absorbent main body and extend in the horizontal direction, and a fixing sheet arranged across the absorbent main body on the non-skin-facing side of the absorbent main body. In one embodiment, it is preferable that the folded-back sheet portion and the end-fixed sheet have a first free portion opposing portion on the waist opening side of the vertical end edge of the absorbent main body, in which the free portions in an unfixed state face each other in the vertical direction. In one embodiment, it is preferable that the end fixing sheet and the fixing sheet have a second free portion opposing portion on the crotch side of the vertical end edge of the absorbent main body, in which the free portions in an unfixed state face each other in the vertical direction. In one embodiment, the first free portion facing portion and the second free portion facing portion are formed continuously along the horizontal direction at least in the side regions located outside each of the longitudinally extending both side edges of the absorbent body, and it is preferable that no elastic member is arranged in the free portion. [Effects of the Invention]

[0007] According to the present invention, a pants-type disposable diaper is provided which is prevented from sticking to the wearer's skin when the wearer sweats. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing one embodiment of a pants-type disposable diaper of the present invention, and is a developed plan view schematically showing the skin-facing side of the diaper in a developed and stretched state. [Figure 2] FIG. 2 is an exploded perspective view of the disposable diaper shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line II-II in FIG. [Figure 4] 4 is a cross-sectional perspective view taken along line III-III in FIG. [Figure 5] 5 is a cross-sectional perspective view taken along line IV-IV in FIG. [Figure 6] FIG. 6 is a perspective view showing a typical state in which the outer layer sheet and the inner layer sheet are joined together. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will now be described based on preferred embodiments with reference to the drawings. Figures 1 to 6 show one embodiment of a pants-type disposable diaper 1 (hereinafter simply referred to as "diaper 1") of the present invention. As shown in FIG. 1 , the diaper 1 has a ventral portion A that is located on the ventral side of the wearer when worn, a dorsal portion B that is located on the dorsal side of the wearer, and a crotch portion C that is located between the ventral portion A and the dorsal portion B. The crotch portion C is a portion that is located in the crotch area of ​​the wearer when the diaper 1 is worn. The ventral portion A is a portion that is located closer to the ventral side of the wearer, i.e., in front of the crotch portion C, when the diaper 1 is worn. The dorsal portion B is a portion that is located closer to the dorsal side of the wearer, i.e., in back of the crotch portion C, when the diaper 1 is worn. As shown in Fig. 1, the diaper 1 has a longitudinal direction X corresponding to the front-to-back direction of a wearer and a transverse direction Y perpendicular to the longitudinal direction. In this specification, the "front-to-back direction of a wearer" refers to the direction extending from the wearer's abdominal side through the crotch region to the dorsal side. The diaper 1 extends in the longitudinal direction X from the abdominal region A through the crotch region C to the dorsal region B.

[0010] As shown in Fig. 1, the diaper 1 is divided into a front body F, which is positioned in front of the wearer (toward the belly) when worn, and a back body R, which is positioned on the wearer's back (toward the rear), with the longitudinal center (longitudinal centerline CLx) as the boundary. The longitudinal centerline CLx is an imaginary line extending in the transverse direction Y, dividing the diaper 1 in an unfolded and stretched state as shown in Fig. 1 into two equal parts in the longitudinal direction X. The "unfolded and stretched state" of the diaper 1 refers to a state in which the diaper 1 is unfolded by separating it at the side seal portions (described later) and stretching the elastic members of each portion until the diaper 1 reaches its designed dimensions (the same dimensions as when the diaper 1 is unfolded flat without any influence of the elastic members). In this specification, unless otherwise specified, the dimensions of each part of the diaper 1 (e.g., the absorbent core 40), such as the length (width) in the longitudinal direction X or the lateral direction Y, refer to the dimensions (design dimensions) when the elastic members of each part are stretched and each part is stretched.

[0011] The diaper 1 comprises an absorbent body 5 having a liquid-retaining absorbent core 4, and an exterior body 3 disposed on the non-skin-facing side of the absorbent body 5. The exterior body 3 has both side edge portions AS and BS along the longitudinal direction X in each of the ventral side portion A and the dorsal side portion B joined together by a known joining method such as adhesive, heat sealing, ultrasonic sealing, etc. As a result, the diaper 1 has a pair of side seal portions (not shown) where the both side edge portions AS and BS are joined together, as well as a waist opening through which the wearer's torso is passed and a pair of leg openings (not shown) through which the wearer's lower legs are passed.

[0012] In this specification, the "skin-facing side" refers to the side of a disposable diaper or a component thereof (e.g., the topsheet 12) that faces the wearer's skin when the disposable diaper is worn, i.e., the side that is relatively close to the wearer's skin, and the "non-skin-facing side" refers to the side of a disposable diaper or a component thereof that faces away from the skin when the disposable diaper is worn, i.e., the side that is relatively far from the wearer's skin. As used herein, "when worn" refers to the normal, proper wearing position, i.e., a state in which the absorbent article is maintained in the correct wearing position.

[0013] The absorbent main body 5 has a rectangular shape in a plan view, extends in the longitudinal direction X, and is disposed at the center of the exterior body 3 in the lateral direction Y, with its longitudinal direction coinciding with the longitudinal direction X of the diaper 1 in the unfolded and stretched state. The absorbent main body 5 is joined to the exterior body 3 by a known joining means such as an adhesive. The absorbent main body 5 has its skin-facing surfaces at both ends in the longitudinal direction X covered with end-fixing sheets 34, and is fixed to the exterior body 3. The end-fixing sheets 34 are joined to the exterior body 3 and the absorbent main body 5 by a known joining means such as an adhesive (see FIG. 2). Details of the joining manner of the end-fixing sheets 34 will be described later.

[0014] The absorbent body 5 comprises a liquid-permeable top sheet 12 that forms the skin-facing side, a liquid-impermeable or liquid-slightly permeable or water-repellent leak-proof sheet 13 that forms the non-skin-facing side, and a liquid-retaining absorbent body 4 arranged between the top sheet 12 and the leak-proof sheet 13, which are integrated together using known joining means such as an adhesive. As shown in Fig. 3, the absorbent body 4 includes an absorbent core 40 and a liquid-permeable core wrap sheet 49 that covers the surface of the absorbent core 40. In the absorbent body 4, the entire surface of the absorbent core 40, including the skin-facing surface and non-skin-facing surface, is covered with the core wrap sheet 49. Alternatively, only the skin-facing surface of the absorbent core 40 may be covered with the core wrap sheet 49. Furthermore, the absorbent body 4 does not necessarily have to include the core wrap sheet 49. The absorbent core 40 has a lower layer core 45 and an upper layer core 41 arranged closer to the skin-facing side than the lower layer core 45 (see FIG. 3). That is, the absorbent core 40 has a layered structure in which the upper layer core 41 and the lower layer core 45 are layered. Alternatively, the absorbent core 40 may have a single-layer structure consisting of only the lower layer core 45, without including the upper layer core 41. Since the absorbent core 40 has the upper layer core 41 arranged on the skin-facing side of the lower layer core 45, the upper layer core 41 forms a convex portion that protrudes from the skin, and when worn, the upper layer core 41 fits snugly against the wearer's crotch and ensures absorption performance.

[0015] The exterior body 3 forms the outer shape of the diaper 1, i.e., the outer shapes of the abdominal portion A, crotch portion C, and back portion B. As shown in Fig. 1, in a plan view in an unfolded and stretched state, the abdominal portion A and back portion B of the exterior body 3 are rectangular in shape, with the length in the horizontal direction Y being longer than the length in the vertical direction X. In the crotch portion C, both side edges along the vertical direction X, i.e., a pair of leg edges LE, LE, form an hourglass shape tapered inward in the horizontal direction Y. In a plan view in an unfolded and stretched state, both side edges of the abdominal portion A and back portion B along the vertical direction X protrude outward in the horizontal direction Y beyond both side edges of the crotch portion C along the vertical direction X. In addition, the outer edge 6 of the abdominal portion A and the outer edge 6 of the back portion B of the exterior body 3 extend in the horizontal direction Y to form a waist opening in the diaper 1 having side seals. That is, these outer edges 6 in the longitudinal direction X become the peripheral edges WE of the waist opening.

[0016] The outer body 3 is constructed by laminating multiple sheets. Specifically, as shown in Fig. 3, the outer body 3 includes an outer layer sheet 31, an inner layer sheet 33, and a fixing sheet 35 laminated in this order from the non-skin-facing side to the skin-facing side. The outer layer sheet 31 forms the outer surface of the diaper 1, i.e., the non-skin-facing side, at least in the ventral portion A and the back portion B. As shown in Figs. 2 and 3, the outer layer sheet 31 is divided into a front outer layer sheet 31A disposed in the front body portion F and a back outer layer sheet 31B disposed in the back body portion R. The inner layer sheet 33 is disposed between the outer layer sheet 31 and the fixing sheet 35, and is fixed by spanning both the outer layer sheets 31A, 31B of the front body portion F and the back body portion R. The inner layer sheet 33 is continuous in the longitudinal direction X from the peripheral edge WE of the waist opening in the ventral portion A to the peripheral edge WE of the waist opening in the back portion B. That is, the inner layer sheet 33 extends continuously over the entire length of the diaper 1, and the front outer layer sheet 31A and the rear outer layer sheet 31B in the longitudinal direction X form the outer surface of the diaper 1. The fixing sheet 35 is disposed on the skin-facing side of the inner layer sheet 33 and on the non-skin-facing side of the absorbent main body 5, crossing the absorbent main body 5, and fixes leg elastic members 37 (described later) between the fixing sheet 35 and the inner layer sheet 33. These sheets 31, 33, and 35 constituting the outer body 3 are joined together by known joining means such as adhesives. The pants-type disposable diaper of this embodiment does not necessarily have to include the outer sheet 31.

[0017] In the outer cover 3, the front outer sheet 31A and the back outer sheet 31B are folded back toward the skin-facing side along the peripheral edge WE of the waist opening to form a folded-back sheet portion 51 (see FIGS. 1 and 2). That is, the front outer sheet 31A and the back outer sheet 31B form the peripheral edge WE of the waist opening, and folded-back sheet portions 51a and 51b of the sheets 31A and 31B extend inward in the longitudinal direction X from the peripheral edge WE. Similar to the outer sheets 31A and 31B described above, the inner sheet 33, which is another component of the exterior body 3, is folded back along the peripheral edge WE of the waist opening toward the skin-facing side to form a folded-back sheet portion 51 that extends inward in the longitudinal direction X. Near the peripheral edge WE of the waist opening of the exterior body 3, the folded-back sheet portions 51a and 51b of the front outer sheet 31A and the back outer sheet 31B overlap with the folded-back sheet portions 51c and 51d of the inner sheet 33 on the skin-facing side (see FIG. 3). The diaper 1 has four folded-up sheet portions 51a, 51b, 51c, and 51d, but may alternatively have one to three of the four folded-up sheet portions 51a, 51b, 51c, and 51d. For example, the diaper 1 may have only the folded-up sheet portions 51a and 51b of the outer-layer sheet 31, or only the folded-up sheet portions 51c and 51d of the inner-layer sheet 33.

[0018] The outer casing 3 includes a plurality of thread-like or strip-like elastic members 32 arranged in a stretched state between the inner-layer sheet 33 and its folded-back sheet portions 51c, 51d. Specifically, a plurality of elastic members 32 (hereinafter referred to as "waist elastic members 32") are arranged in a stretched state in the horizontal direction Y and intermittently at predetermined intervals in the vertical direction X in each of the abdominal portion A and the back portion B, which are arranged around the waist of the wearer. The waist elastic members 32 are arranged between both side edges along the vertical direction X in each of the abdominal portion A and the back portion B, i.e., between the side seal portions in the horizontal direction Y, in a region extending outward in the vertical direction X from the edge of the absorbent main body 5 in the vertical direction X. This region is arranged around the waist of the wearer and in the vicinity thereof when worn. The waist elastic members 32 extend over substantially the entire length of the abdominal portion A and the back portion B in the horizontal direction Y, and are arranged in an elastically stretchable state. This forms a substantially continuous annular waist gather along the entire circumference of the waist opening.

[0019] The outer casing 3 includes a plurality of thread- or strip-like leg elastic members 37 arranged in a stretched state between the inner-layer sheet 33 and the fixing sheet 35. Specifically, one or more leg gather-forming leg elastic members 37 are arranged in a stretched state at leg edges LE that form the peripheries of each of the pair of leg openings in the front body F (see FIGS. 1 and 2). As a result, leg gathers are formed at the peripheries of each of the pair of leg openings in the front body F. In the diaper 1 of this embodiment, the leg elastic members 37 are arranged only in the front body F. That is, the leg elastic members 37 are not arranged in the back body R. Alternatively, leg elastic members 37 may be arranged at the leg edges LE of the front body F and the back body R, respectively.

[0020] The folded-back sheet portion 51 and the end-fixed sheet 34 have a first free-portion facing portion, where the unfixed free portions face each other in the longitudinal direction X, closer to the waist opening than the end edge in the longitudinal direction X of the absorbent main body 5. FIG. 4 shows a first free-portion facing portion 73 consisting of a free portion 71 of the folded-back sheet portion 51c and a free portion 72 of the end-fixed sheet 34A. The folded-back sheet portion 51c has the free portion 71 in an unfixed state, located closer to the end-fixed sheet 34 in the longitudinal direction X, and a fixed portion 70, located farther from the end-fixed sheet 34 in the longitudinal direction X, and fixed to the inner-layer sheet 33 constituting the outer body 3. Similarly, the end-fixed sheet 34A has the free portion 72 in an unfixed state, located closer to the folded-back sheet portion 51c in the longitudinal direction X, and a fixed portion 70, located farther from the folded-back sheet portion 51c in the longitudinal direction X, and fixed to the inner-layer sheet 33 constituting the outer body 3. The free portion 71 of the folded-back sheet portion 51 and the free portion 72 of the end-fixing sheet 34 are not joined to any other member. The free edges of the free portions 71, 72 face each other to form a first free-portion facing portion 73. The free edges of the free portions 71, 72 extend along the lateral direction Y of the diaper 1.

[0021] The free portions 71, 72 improve the breathability of the diaper 1 and allow the wearer's sweat to evaporate more quickly. This prevents the sheets constituting the diaper 1 from sticking to the wearer's skin when the wearer sweats. Furthermore, the two free portions 71, 72 face each other to form the first free portion facing portion 73, improving breathability in both directions of the diaper 1, from the ventral portion A to the dorsal portion B and from the dorsal portion B to the ventral portion A, thereby allowing the wearer's sweat to evaporate more quickly. For this purpose, the free portions 71, 72 are preferably made of, for example, nonwoven fabric.

[0022] The first free portion facing portions 73 are formed continuously along the lateral direction Y at least in the side regions D located outward of both side edges extending in the longitudinal direction X of the absorbent main body 5. By forming the first free portion facing portions 73 continuously along the lateral direction Y, the breathability of the diaper 1 can be improved over a wide area in the lateral direction Y. On the other hand, the first free portion facing portions 73 may or may not be formed in a central region E (see FIG. 1) located inside each of both side edges extending in the longitudinal direction X of the absorbent main body 5. From the viewpoint of further enhancing the above-mentioned breathability improvement effect, it is preferable that the first free portion facing portions 73 are also formed in the central region E.

[0023] 4 is composed of the folded sheet portion 51c and the end fixing sheet 34A, the components constituting the first free portion facing portion 73 are not limited to these. For example, the first free portion facing portion 73 may be composed of the folded sheet portion 51d and the end fixing sheet 34B. Alternatively, in an embodiment in which the folded sheet portion 51c is not present, the first free portion facing portion 73 may be composed of the folded sheet portion 51a and the end fixing sheet 34A. The diaper 1 may have one or more first free portion facing portions 73. In this embodiment, one first free portion facing portion 73 is provided in each of the abdominal portion A and the back portion B. Specifically, the first free portion facing portion 73 in the abdominal portion A comprises the folded-back sheet portion 51c and the end-fixing sheet 34A, and in the back portion B comprises the folded-back sheet portion 51d and the end-fixing sheet 34B. The first free portion facing portion 73 differs from a second free portion facing portion 83 described below in that the free portion 71 of the folded-back sheet portion 51 constitutes the first free portion facing portion 73. Unlike the other free portions, the free portion 71 of the folded-back sheet portion 51 can be formed simply by folding back the sheet that constitutes the exterior body 3 without using an additional sheet member, which is advantageous in that manufacturing costs can be reduced.

[0024] The end fixing sheet 34 and the fixing sheet 35 also have a second free portion facing portion, where the free portions of the unfixed state face each other in the longitudinal direction X, closer to the crotch portion than the end edges in the longitudinal direction X of the absorbent main body 5. FIG. 5 shows a second free portion facing portion 83 consisting of a free portion 81 of the end fixing sheet 34A and a free portion 82 of the fixing sheet 35. In side regions D located outward from each of the both side edges extending in the longitudinal direction X of the absorbent main body 5, the end fixing sheet 34A has the free portion 81 in an unfixed state and a fixed portion 70 fixed to the inner layer sheet 33 constituting the exterior body 3. The free portion 81 is located closer to the fixing sheet 35 in the longitudinal direction X than the fixed portion 70. Similarly, in the side regions D, the fixing sheet 35 has the free portion 82 in an unfixed state and the fixed portion 70 fixed to the inner layer sheet 33 constituting the exterior body 3. The free portion 82 is disposed closer to the end fixing sheet 34A in the longitudinal direction X than the fixing portion 70. The free portion 81 of the end fixing sheet 34A and the free portion 82 of the fixing sheet 35 are not joined to any other member. The free edges of the free portions 81, 82 face each other to form a second free portion facing portion 83. The free edges of the free portions 81, 82 extend along the transverse direction Y of the diaper 1. As is clear from FIG. 1, the second free portion facing portion 83 is located closer to the crotch portion than the edge of the absorbent main body 5 in the longitudinal direction X. However, when the second free portion facing portion 83 is located in the crotch portion C, the phrase "located on the crotch portion side" means "located closer to the longitudinal centerline CLx."

[0025] The second free portion facing portion 83 and the free portions 81, 82 constituting the second free portion facing portion 83, like the first free portion facing portion 73 and the free portions 71, 72 constituting the first free portion facing portion 73, improve the breathability of the diaper 1. By including the second free portion facing portion 83 in addition to the first free portion facing portion 73, the breathability of the diaper 1 is improved over a wide area in the longitudinal direction X, and the sheets constituting the diaper 1 are more effectively prevented from sticking to the wearer's skin. For this purpose, the free portions 81, 82 are preferably made of, for example, a nonwoven fabric.

[0026] 5, the second free portion facing portions 83 are continuously formed along the transverse direction Y in the side regions D located outward of each of the two side edges extending in the longitudinal direction X of the absorbent main body 5. By continuously forming the second free portion facing portions 83 along the transverse direction Y, the breathability of the diaper 1 can be further improved. On the other hand, in the central region E, the fixing sheet 35 is located below the absorbent main body 5, so no free portion is formed. Therefore, the second free portion facing portion 83 does not exist in the central region E. In this embodiment, the end fixing sheet 34A is fixed to the absorbent main body 5 in the central region E, and no free portion is formed. Alternatively, the end fixing sheet 34A in the central region E may have a free portion in an unfixed state.

[0027] In this embodiment, the second free portion facing portion 83 is located on the front body F, but the position of the second free portion facing portion 83 is not limited to this. For example, in an embodiment in which the leg elastic members 37 and the fixing sheet 35 are arranged on both the front body F and the back body R, the second free portion facing portion 83 may be located on both the front body F and the back body R, or on only one of them.

[0028] Each free portion present in the diaper 1 improves the breathability of the diaper 1 and has the effect of facilitating faster evaporation of the wearer's sweat. This prevents the sheets constituting the diaper 1 from sticking to the wearer's skin when the wearer sweats. In particular, the first free portion facing portion 73 and the second free portion facing portion 83, where two free portions face each other, have excellent breathability in both directions, from the ventral portion A to the dorsal portion B of the diaper 1 and from the dorsal portion B to the ventral portion A, allowing the wearer's sweat to evaporate more quickly.

[0029] No elastic member is provided in the free portions 71, 72, 81, and 82. In other words, each of the free portions 71, 72, 81, and 82 is a non-elastic portion. In this specification, "non-elastic" refers to the property of returning to a length at least 1.5 times its original length when stretched to twice its original length and then released from the stretched state. The absence of an elastic member prevents an increase in wearing pressure due to the presence of an elastic member. This makes it less likely that the movement of each of the free portions 71, 72, 81, and 82 will be hindered, further enhancing the breathability-improving effect of each of the free portions 71, 72, 81, and 82.

[0030] In this embodiment, the first free portion facing portion 73 and the second free portion facing portion 83 both include the same end-fixing sheet 34A. That is, the end-fixing sheet 34A has two free portions 72, 81 arranged along the longitudinal direction X and extending along the transverse direction Y, and has a fixed portion 70 located between the two free portions 72, 81. In other words, the free portions 72, 81 are present in a single end-fixing sheet 34A. Inclusion of the same end-fixing sheet in the first free portion facing portion 73 and the second free portion facing portion 83 in this manner is preferable from the perspectives of reducing manufacturing costs, making it easier to adjust the positions of the free portions 72, 81, and optimizing the breathability of the pants-type disposable diaper of the present invention. However, the diaper of the present invention is not limited to the above embodiment. For example, the first free portion facing portion 73 may be composed of the folded-back sheet portion 51d and the end-fixing sheet 34B, and the second free portion facing portion 83 may be composed of the end-fixing sheet 34A and the fixing sheet 35. In such an embodiment, the first free portion facing portion 73 and the second free portion facing portion 83 do not include the same end-fixing sheet 34.

[0031] The outer cover 3 constituting the diaper 1 preferably includes a stretchable sheet. In the outer cover 3, the outer layer sheet 31 constituting the outer cover 3 is preferably a stretchable sheet. In this case, the outer layer sheet 31 preferably has stretchability at least along the lateral direction Y. The stretchable outer layer sheet 31 imparts stretchability to the diaper 1 in the ventral side portion A and the dorsal side portion B. This allows the diaper 1 to fit the wearer's body. Instead of the stretchable outer layer sheet 31, other stretchable members, such as thread-like or strip-like elastic members, can be disposed on a non-stretchable sheet member to impart stretchability to the ventral portion A and the dorsal portion B. However, providing stretchability to the diaper 1 by disposing a stretchable sheet tends to make the application pressure in the ventral portion A and the dorsal portion B more uniform, and the movement of each of the free portions 71, 72, 81, and 82 less likely to be hindered. This further enhances the breathability-improving effect of each of the free portions 71, 72, 81, and 82.

[0032] The stretchable sheet used in the present invention may preferably be, for example, (1) a stretchable nonwoven fabric in which a stretchable fiber layer is integrated on one or both sides of an elastic fiber layer, (2) a stretchable nonwoven fabric in which a stretchable fiber layer is integrated on one or both sides of a net-like elastic sheet, (3) a stretchable nonwoven fabric in which a stretchable fiber layer is integrated on one or both sides of an elastic sheet made of an elastic film, or (4) a stretchable nonwoven fabric in which a large number of elastic filaments arranged so as to extend in one direction without crossing each other are integrated into a stretchable fiber layer. The term "stretchable fiber layer" as used in this specification includes not only a fiber layer that is stretchable before being integrated with an elastic material, but also a fiber layer that is made stretchable by mechanical processing or the like after being integrated with an elastic material. Methods for integrating the elastic fiber layer and the extensible fiber layer include, for example, laminating them and entangling the fibers by hydroentangling or air-through, or bonding them by heat embossing, adhesives, ultrasonic waves, etc. As the elastic fiber, a fiber made from a thermoplastic elastomer such as a styrene-based elastomer, a polyolefin-based elastomer, a polyester-based elastomer, or a polyurethane-based elastomer, or an elastic resin such as rubber can be used. As the non-elastic fiber, a fiber made from a thermoplastic resin can be used.

[0033] The stretchable nonwoven fabric (4) may be, for example, one having an integrated structure in which thread-like elastic filaments are sandwiched between extensible fiber layers mainly composed of inelastic fibers. Such a stretchable nonwoven fabric is composed of two fiber sheets as fiber layers and elastic filaments interposed between the two sheets. This stretchable nonwoven fabric can be produced, for example, according to the method described in JP 2009-61743 A.

[0034] In the stretchable nonwoven fabric of (4) above, both of the two fiber sheets are stretchable. These two fiber sheets are stretchable in the same direction as the extension of the elastic filaments. Stretchable forms include (a) a form in which the constituent fibers of the sheet themselves stretch, and (b) a form in which the constituent fibers themselves do not stretch, but the sheet as a whole stretches as a result of mechanical processing or the like causing fibers bonded at their intersections to separate, or structural changes to the three-dimensional structure formed by multiple fibers due to fiber-to-fiber bonding, or the constituent fibers to tear. Examples of mechanical processing in (b) above include heat treatment, inter-roll stretching, meshing stretching using teeth or gears, and tensile stretching using a tenter.

[0035] In the stretchable nonwoven fabric of (4) above, the elastic filaments can be formed by stretching the elastic resin in a molten or softened state. The multiple elastic filaments are each continuously arranged in one direction, extending in that direction without crossing each other. The elastic filaments are bonded to the two fiber sheets in a substantially unstretched state. This bonding is achieved by fusing the constituent fibers (non-elastic fibers) of the two fiber sheets to the elastic filaments while they are embedded in the elastic filaments, rather than using an adhesive such as a hot-melt adhesive. Therefore, no adhesive is present between the two fiber sheets (stretchable fiber layers mainly composed of non-elastic fibers) and the elastic filaments bonded thereto.

[0036] The two fiber sheets constituting the stretchable nonwoven fabric (4) can each be a variety of nonwoven fabrics, such as air-through nonwoven fabrics, heat-rolled nonwoven fabrics, spunlace nonwoven fabrics, spunbonded nonwoven fabrics, and meltblown nonwoven fabrics. The two fiber sheets can be the same or different. As used herein, "same type of sheet" refers to sheets that are identical in terms of the sheet manufacturing process, the type of fibers constituting the sheet, the fiber diameter and length of the fibers constituting the sheet, the sheet thickness, and the basis weight. If at least one of these is different, the sheets are considered "different types of sheets." Elastic filaments are made from, for example, thermoplastic elastomers or rubber. Thermoplastic elastomers, in particular, can be melt-spun using an extruder in the same way as ordinary thermoplastic resins, and the elastic filaments obtained in this way are easily heat-sealed, making them suitable for stretchable nonwoven fabrics. From the viewpoint of further improving the fit to the wearer's body, it is preferable that the outer layer sheet 31 is made of the stretchable nonwoven fabric (4) above. In this case, the extending direction of the elastic filaments of the outer layer sheet 31 coincides with the transverse direction Y.

[0037] When the exterior body 3 includes a stretchable sheet, the stretchable sheet is preferably intermittently joined to another sheet constituting the exterior body 3 while stretched in the transverse direction Y. For example, the outer layer sheet 31, which is a stretchable sheet, can be intermittently joined to the inner layer sheet 33 by a known joining means such as an adhesive while stretched in the transverse direction Y. This allows the exterior body 3 to have a pleated structure in its natural state (relaxed state) as shown in Fig. 6. In the exterior body 3 of this embodiment, joints 91 between the outer layer sheet 31 and the inner layer sheet 33 are formed intermittently in the transverse direction Y and continuously along the longitudinal direction X. By having the pleated structure of the outer body 3 as shown in Figure 6, the contact area between the inner layer sheet 33 and the wearer's skin is reduced, further preventing the inner layer sheet 33 from sticking to the wearer's skin. In order to appropriately control the wearing pressure of the diaper 1, the outer layer sheet 31 is intermittently joined to the inner layer sheet 33 while being stretched in the transverse direction Y by preferably 140% to 260%, more preferably 160% to 240%, and even more preferably 180% to 220%.

[0038] From the viewpoint of reducing the stuffiness felt by the wearer, it is preferable that at least one of the end fixing sheets 34A, 34B and the fixing sheet 35 be a hydrophilic sheet. Furthermore, from the viewpoint of further enhancing the effect of reducing the stuffiness felt by the wearer, it is more preferable that all of the end fixing sheets 34A, 34B and the fixing sheet 35 be hydrophilic sheets. From the same viewpoint, it is preferable that the folded sheet portions 51c and 51d have hydrophilic properties. Examples of hydrophilic sheets include paper, nonwoven fabric, cloth, and synthetic sponge formed by foaming synthetic resin. Among these, nonwoven fabric is preferably used because it has relatively high tensile strength even when thin and can be made flexible. Preferred nonwoven fabrics include those containing hydrophilic fibers as constituent fibers and those containing synthetic fibers that have been given hydrophilic properties as constituent fibers. The basis weight of the nonwoven fabric is 13 g / m. 2 More than 22g / m 2 Preferably, it is 15 g / m or less. 2 More than 20g / m2 It is more preferable that:

[0039] The present invention has been described above based on its preferred embodiments, but the present invention is not limited to the above embodiments and can be modified as appropriate within the scope of the invention. For example, the diaper 1 of the above-described embodiment has leg elastic members 37 only on the front body panel F, but it may have leg elastic members 37 on both the front body panel F and the back body panel R. Furthermore, in the diaper 1 of the above-described embodiment, the lower core 45 has an hourglass shape, but the side edges of the lower core 45 do not have to be constricted inward in the horizontal direction Y, and the side edges may be parallel to the vertical direction X. Furthermore, the absorbent core 40 is not limited to a two-layer structure, but may be, for example, a single-layer structure.

[0040] In relation to the above-described embodiment, the present invention further discloses the following pants-type disposable diaper. [Explanation of symbols]

[0041] 1. Pants-type disposable diapers (diapers) 3. Exterior body 4. Absorbent 5. Absorbent body 31 outer layer sheet 33 Inner layer sheet 34 End fixing sheet 35 Fixing sheet 40 absorbent core 70 Fixed part 71,72,81,82 Free part 73 First free portion facing portion 83 Second free part facing part 91 Joint

Claims

1. A pants-type disposable diaper having a ventral side portion arranged on the ventral side of a wearer, a dorsal side portion arranged on the dorsal side of the wearer, and a crotch portion located between the ventral side portion and the dorsal side portion, the diaper comprising: an absorbent main body having an absorbent body including an absorbent core; and an exterior body arranged on the non-skin-facing side of the absorbent main body; a longitudinal direction extending from the ventral side portion through the crotch portion to the dorsal side portion and a lateral direction perpendicular to the longitudinal direction; and a waist opening and a pair of leg openings, The sheet constituting the outer body has a folded sheet portion formed by folding back along the peripheral edge of the waist opening toward the skin-facing side, an end fixing sheet arranged to cover the longitudinal end of the absorbent main body and extend in the horizontal direction, and a fixing sheet arranged across the absorbent main body on the non-skin-facing side of the absorbent main body, the folded-back sheet portion and the end-fixed sheet have a first free portion facing portion, in which free portions in an unfixed state face each other in the longitudinal direction, on the waist opening side of the longitudinal edge of the absorbent main body; the end fixing sheet and the fixing sheet have a second free portion facing portion, in which the free portions in an unfixed state face each other in the vertical direction, on the crotch portion side of the vertical end edge of the absorbent main body; A pants-type disposable diaper, wherein the first free portion facing portion and the second free portion facing portion are formed continuously along the horizontal direction at least in side regions located outside each of both side edges extending in the vertical direction of the absorbent main body, and no elastic member is arranged in the free portion.

2. The pants-type disposable diaper according to claim 1 , wherein the outer cover includes a stretchable sheet.

3. the stretchable sheet is intermittently joined to another sheet constituting the exterior body in a state stretched in the lateral direction, The pants-type disposable diaper according to claim 2, wherein the outer cover has a pleated structure in a natural state.

4. 3. The pants-type disposable diaper according to claim 1, wherein the first free portion facing portion and the second free portion facing portion include the same end fixing sheet.

5. 3. The pants-type disposable diaper according to claim 1, wherein the end fixing sheet or the fixing sheet is a hydrophilic sheet.

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