Pants-type disposable diaper

Abstract

To provide a pants-type disposable diaper having an excellent fitting property and external appearance when being worn.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. The absorbent core 40 includes a lower-layer core 45 and an upper-layer core 41. The upper-layer core 41 and the lower-layer core 45 respectively include low-rigidity parts 42 and 46 extending in a longitudinal direction X at positions spaced from both side edges along the longitudinal direction X of the upper-layer core 41 toward a center side. The outer wrapper 3 includes a stretchable sheet with stretchability in a lateral direction Y in a dorsal part B. In plan view, a low-rigidity-part overlapping area Kt where the low-rigidity part 42 of the upper-layer core 41 and the low-rigidity part 46 of the lower-layer core 45 overlap each other and at least a part of a joint area S of the absorbent body 5 and the outer wrapper 3 overlap each other. In the dorsal part B, the stretchable sheet and at least a part of the lower-layer core 45 overlap each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In general, pants-type disposable diapers are provided with an absorbent body including an absorbent core that serves as a main liquid absorbing portion. It is also known that the absorbent core is provided with slits in consideration of wearing comfort, absorption performance, and the like. For example, Patent Document 1 describes an absorbent article in which a central slit is formed in the center of the absorbent core in the width direction and side slits are formed on both sides of the central slit. The document also describes that the absorbent core has a two-layer structure consisting of a first layer and a second layer disposed on the non-skin-facing side of the first layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-177309 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes that when the disposable diaper of the same document is worn, the central slit portion deforms to be convex toward the wearer and forms a top surface, while the side slit portion deforms to be convex toward the non-skin-facing surface side, and the cross section along the width direction of the absorbent body becomes W-shaped. Since the disposable diaper of the same document deforms to be convex toward the non-skin-facing surface side at the side slit portion, the side slit portion does not easily adhere to the wearer's skin. Therefore, the fit of the absorbent article of the same document may be reduced. In addition, while a disposable diaper is required to have an appearance like underwear when worn, the same document does not consider this point at all, and there is room for improvement. [Means for solving the problem]

[0005] The present invention relates to a pants-type disposable diaper comprising an absorbent main body having an absorbent body including an absorbent core, an absorbent core having a ventral side portion arranged on the ventral side of a wearer, a crotch portion located between the ventral side portion and the crotch portion, and an outer body arranged on the non-skin-facing side of the absorbent main body, and having a vertical direction extending from the ventral side portion through the crotch portion to the posterior side portion and a horizontal direction perpendicular to the vertical direction, the diaper being divided, with the center of the vertical direction as a boundary, into a front body portion arranged on the ventral side of the wearer and a rear body portion arranged on the posterior side of the wearer when worn, and having a waist opening and a pair of leg openings. In one embodiment, the absorbent core preferably has a lower layer core and an upper layer core disposed closer to the skin-facing surface than the lower layer core. It is preferable that both lateral ends and one or both longitudinal ends of the lower core extend beyond edges of the upper core. It is preferable that each of the upper core and the lower core has a low stiffness portion extending in the longitudinal direction at a position spaced from both side edges of the upper core along the longitudinal direction toward the center. The exterior body preferably has a stretchable sheet on the rear side that is stretchable in the lateral direction. It is preferable that the upper core has a low rigidity portion overlapping region in which the low rigidity portion of the lower core overlaps with the low rigidity portion of the upper core in a plan view. When viewed in a plan view, it is preferable that the low stiffness overlap region overlaps with at least a portion of the joining region of the absorbent body and the outer body, and that in the back side portion the elastic sheet overlaps with at least a portion of the lower core. Effect of the Invention

[0006] The pants-type disposable diaper of the present invention is excellent in fit and appearance when worn. [Brief description of the drawings]

[0007] [Figure 1]FIG. 1 is a view showing one embodiment of a pants-type disposable diaper of the present invention, and is a developed plan view showing a schematic view of the skin-facing surface side of the diaper in an unfolded and stretched state. [Diagram 2] FIG. 2 is an exploded perspective view of the disposable diaper shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a plan view showing a joining region between an absorbent main body and an exterior body in the diaper shown in FIG. [Figure 6] 6(a) is a rear view showing the diaper shown in FIG. 1 in a worn state, and FIG. 6(b) is a cross-sectional view showing a schematic view of the diaper shown in FIG. 1 in a worn state. [Figure 7] FIG. 7(a) is a perspective view showing a schematic diagram of a saddle-shaped curved surface in the diaper shown in FIG. 1, FIG. 7(b) is a cross-sectional view in the X direction of FIG. 7(a), and FIG. 7(c) is a cross-sectional view in the Y direction of FIG. 7(a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 arranged on the ventral side of the wearer when worn, a dorsal portion B arranged on the dorsal side of the wearer, and a crotch portion C located between the ventral portion A and the dorsal portion B. The crotch portion C is a portion arranged in the crotch area of ​​the wearer when the diaper 1 is worn. The ventral portion A is a portion arranged on the ventral side, i.e., in front of the wearer, of the crotch portion C when the diaper 1 is worn. The dorsal portion B is a portion arranged on the dorsal side, i.e., behind the wearer, 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 thereto. In this specification, the "front-to-back direction of a wearer" refers to a 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.

[0009] As shown in Fig. 1, the diaper 1 is divided into a front body F, which is disposed in front of the wearer (toward the stomach) when worn, and a rear body R, which is disposed on the wearer's back (toward the rear), with the vertical center (vertical centerline CLx) as the boundary. The vertical centerline CLx is an imaginary line extending in the horizontal direction Y, dividing the diaper 1 in an unfolded and stretched state as shown in Fig. 1 in half in the vertical direction X. The "unfolded and stretched state" of the diaper 1 refers to a state in which the diaper 1 is separated at the side seal portions described below to be unfolded, and the elastic members of each portion of the diaper 1 in the unfolded state are stretched to the 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, each dimension 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, refers to the dimension (design dimension) when the elastic member of each part is stretched and each member is stretched.

[0010] The diaper 1 comprises an absorbent body 5 having a liquid-retentive absorbent 4, and an exterior body 3 arranged on the non-skin-facing side of the absorbent body 5. The exterior body 3 has both side edge portions AS, BS along the longitudinal direction X in each of the ventral side portion A and the back side portion B joined to each other by a known joining means 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, BS are joined to each other, and further has a waist opening through which the wearer's torso passes, and a pair of leg openings (not shown) through which the wearer's lower legs pass.

[0011] In this specification, the "skin-facing side" refers to the side of the disposable diaper or its constituent members (e.g., the topsheet 12) that faces the wearer's skin when the disposable diaper is worn, i.e., the side relatively closer to the wearer's skin, and the "non-skin-facing side" refers to the side of the disposable diaper or its constituent members that faces the side opposite the skin side when the disposable diaper is worn, i.e., the side relatively farther from the wearer's skin. "When worn" here refers to the normal, proper wearing position, i.e., the state in which the absorbent article (disposable diaper) is maintained in the correct wearing position.

[0012] The absorbent main body 5 has a rectangular shape in a plan view, extends in the vertical direction X, and is disposed at the center of the exterior body 3 in the horizontal direction Y with its longitudinal direction coinciding with the vertical direction X of the diaper 1 in an 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. In this embodiment, the joining region S between the absorbent main body 5 and the exterior body 3 has a substantially rectangular shape extending along the vertical direction X, as shown in Fig. 5. The joining region S includes a central joining region Sc located in the central region of the absorbent main body 5 in the horizontal direction Y, and side joining regions Ss, Ss located on both sides of the central joining region Sc.

[0013] In the absorbent main body 5 of this embodiment, the skin-facing surfaces of both ends in the longitudinal direction X are covered with end fixing sheets 34, 34 and 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 Figs. 1 and 2).

[0014] The absorbent body 5 comprises a liquid-permeable surface sheet 12 which forms the skin-facing side, a liquid-impermeable or poorly liquid-permeable or water-repellent leak-proof sheet 13 which forms the non-skin-facing side, and a liquid-retaining absorbent 4 arranged between the surface sheet and the leak-proof sheet, which are integrated together using known joining means such as an adhesive. As shown in Fig. 3, the absorbent body 4 of this embodiment is configured to include an absorbent core 40 and a core wrap sheet 49 that covers the surface of the absorbent core 40. The absorbent body 4 of this embodiment has the entire surface, including the skin-facing surface and the non-skin-facing surface, covered with the core wrap sheet 49. Alternatively, the skin-facing surface of the absorbent core 40 may be covered with the liquid-permeable core wrap sheet 49. The absorbent body 4 may not include the core wrap sheet 49. Details of the absorbent core 40 will be described later.

[0015] The absorbent body 5 of this embodiment has elastic members 48 (hereinafter also referred to as "intermediate elastic members 48") extending in the vertical direction X on both sides in the horizontal direction Y. The intermediate elastic members 48 of this embodiment are disposed in a stretched state between the topsheet 12 and the leakproof sheet 13 on the outer side in the horizontal direction Y of the absorbent body 4. When the absorbent main body 5 includes an intermediate elastic member 48, the intermediate elastic member 48 may be disposed in a stretched state between the core wrap sheet 49 and the absorbent core 40, or may be disposed in a stretched state between the topsheet 12 and the absorbent core 40. The position of the intermediate elastic member 48 in the height direction Z is not particularly limited, and the position in the height direction Z may be different between the unfolded and stretched state of the diaper 1 and the natural state of the diaper 1. For example, the intermediate elastic member 48 may be located approximately in the center of the height of the absorbent body 4 in the natural state, or may be located on the non-skin-facing side of the center of the height of the absorbent body 4 in the unfolded and stretched state.

[0016] The diaper 1 of this embodiment has a pair of leakage-preventing cuffs 6, 6 made of a liquid-resistant or water-repellent and breathable sheet material on both left and right sides along the longitudinal direction X of the skin-facing surface of the absorbent body 5 (see Figs. 1 and 3). The leakage-preventing cuffs 6 of this embodiment have a cuff-forming sheet 60 and a cuff elastic member 61, and the cuff elastic member 61 is arranged in a stretched state between the cuff-forming sheet 60 folded in half. The leakage-preventing cuffs 6 have free inner ends in the transverse direction Y and free outer ends in the transverse direction Y that are rolled up on the non-skin-facing side of the absorbent body 5, i.e., the non-skin-facing side of the leakage-preventing sheet 13, and are fixed between the leakage-preventing sheet 13 and the exterior body 3 with an adhesive or the like. Near the free ends of the leakage-preventing cuffs 6, one or more thread-like cuff elastic members 61 extending in the longitudinal direction are arranged in a stretched state (see Fig. 3). The leakage preventing cuffs 6 stand up at least at the crotch portion C as the cuff elastic members 61 arranged in a stretched state contract, thereby preventing the outflow of excreted liquids such as urine in the lateral direction Y outward. For ease of explanation, the leak-proof cuffs 6 are omitted from FIG.

[0017] The exterior body 3 forms the outer shape of the diaper 1, that is, the outer shapes of each of the abdominal portion A, the crotch portion C, and the back portion B. As shown in FIG. 1, in a plan view in an unfolded and stretched state, the abdominal portion A and the back portion B of the exterior body 3 have a rectangular shape in which the length in the horizontal direction Y is longer than the vertical direction X, and 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 narrowed toward the inside in the horizontal direction Y. In the plan view in an unfolded and stretched state, the exterior body 3 of this embodiment has both side edges along the vertical direction X of the abdominal portion A and the back portion B protruding outward in the horizontal direction Y more than both side edges along the vertical direction X of the crotch portion C. In addition, the outer edge WE in the vertical direction X of the abdominal portion A and the outer edge WE in the vertical direction X 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 a side seal portion. That is, these outer edges in the longitudinal direction X form the peripheral edges WE of the waist opening.

[0018] The exterior body 3 is constructed by laminating a plurality of sheets. As shown in FIG. 2, the exterior body 3 of this embodiment is formed by laminating an outer layer sheet 31, an inner layer sheet 33, and a fixing sheet 35 in this order from the non-skin-facing side to the skin-facing side. The outer layer sheet 31 forms the outer surface, i.e., the non-skin-facing surface, of the diaper 1 at least in the abdominal side portion A and the back side portion B, and is divided into a front outer layer sheet 31a arranged in the front body portion F and a back outer layer sheet 31b arranged in the back body portion R, as shown in FIGS. 1 and 2. The inner layer sheet 33 is arranged between the outer layer sheet 31 and the fixing sheet 35, and is fixed by bridging both the outer layer sheets 31a and 31b of the front body portion F and the back body portion R. The inner layer sheet 33 of this embodiment is continuous in the longitudinal direction X from the peripheral edge WE of the waist opening of the abdominal side portion A to the peripheral edge WE of the waist opening of the back side portion B. That is, the inner layer sheet 33 is continuous over the entire length of the diaper 1, and forms the outer surface of the diaper 1 between the front outer layer sheet 31a and the rear outer layer sheet 31b in the longitudinal direction X. The fixing sheet 35 is disposed on the skin-facing side of the inner layer sheet 33, and fixes leg elastic members 37 (described later) between the fixing sheet 35 and the inner layer sheet 33. These sheets 31, 33, 35 constituting the exterior body 3 are joined by a known joining means such as an adhesive.

[0019] In the exterior body 3 of this embodiment, the outer sheets 31a, 31b are folded back toward the skin-facing side along the peripheral edge WE of the waist opening (see FIG. 2). That is, the outer sheets 31a, 31b form the peripheral edge WE of the waist opening, and the folded-back portions of the sheets 31a, 31b extend inward in the longitudinal direction X from the peripheral edge WE. In the exterior body 3 of this embodiment, the inner layer sheet 33 is also folded back toward the skin-facing side along the peripheral edge WE of the waist opening, similar to the outer layer sheets 31a and 31b described above. In the vicinity of the peripheral edge WE of the waist opening of the exterior body 3 (not shown in FIG. 4), the folded back portions of the outer layer sheets 31a and 31b and the folded back portion of the inner layer sheet 33 overlap on the skin-facing side (see FIG. 4).

[0020] The exterior body 3 of this embodiment includes a plurality of thread-like or band-like elastic members 32 sandwiched and fixed in a stretched state in the folded-back portion of the inner layer sheet 33. Specifically, in the region of the ventral portion A and the back portion B that is arranged around the waist of the wearer, 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 at predetermined intervals in the vertical direction X. The waist elastic members 32 are arranged between both side edges along the vertical direction X of the ventral portion A and the back portion B, i.e., between the side seal portions in the horizontal direction Y, in a region that extends outward in the vertical direction X from the end edge of the absorbent main body 5 in the vertical direction X. Such a 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 ventral portion A and the back portion B in the horizontal direction Y of the exterior body 3, and are arranged in a state in which elastic stretchability is expressed. This forms a substantially continuous annular waist gather around the entire circumference of the waist opening.

[0021] The exterior body 3 includes a plurality of thread-like or band-like leg elastic members 37 arranged in a stretched state between the inner layer sheet 33 and the fixing sheet 35. Specifically, one or a plurality of leg elastic members 37 for forming leg gathers are arranged in a stretched state at leg edges LE forming the peripheries of each of a pair of leg openings in the front body F (see FIG. 1). 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 provided at the leg edges LE of the front body piece F and the back body piece R, respectively.

[0022] The exterior body 3 has a stretchable sheet in the back portion B that is stretchable along the lateral direction Y. Furthermore, the exterior body 3 may also have a stretchable sheet in the ventral portion A that is stretchable along the lateral direction Y. In this embodiment, the exterior body 3 has a stretchable sheet in each of the back portion B and the ventral portion A. Specifically, the front outer layer sheet 31a and the rear outer layer sheet 31b are stretchable sheets. The exterior body 3 may have a stretchable sheet only in the back portion B, but from the viewpoint of further improving the fit to the wearer's body, it is preferable that the exterior body 3 has a stretchable sheet in each of the back portion B and the ventral portion A.

[0023] The outer casing 3 of this embodiment has a front elastic region FE in the front body F that is elastic in the lateral direction Y, and a rear elastic region RE in the rear body R that is elastic in the same direction Y. The front elastic region FE and the rear elastic region RE are collectively referred to as "elastic regions". In this embodiment, these "elastic regions" are made of an elastic sheet that is one of the multiple sheets that make up the outer casing 3. In this embodiment, the elastic region is made of a front outer layer sheet 31a and a rear outer layer sheet 31b. The outer casing 3 is provided with an elastic sheet that is elastic, so that the diaper 1 fits the body when worn, and has an appearance like underwear.

[0024] A stretchable sheet is a sheet that has stretchability in the lateral direction Y, and whose total length b in the lateral direction Y after stretching and releasing is 1 / 3 or less of the stretch amount. "Total length b in the lateral direction Y after stretching and releasing" is the total length in the lateral direction Y of the stretchable sheet when it is pulled in the lateral direction Y to its maximum stretch and then the tensile force is released. "Stretch amount" is the length (ab) obtained by subtracting the total length b in the lateral direction Y of the stretchable sheet when the tensile force in the maximum stretched state is released from the total length a in the lateral direction Y of the stretchable sheet when it is in its maximum stretched state.

[0025] As the elastic sheet used in the present invention, for example, (1) an elastic nonwoven fabric having a stretchable fiber layer integrated on both sides or one side of an elastic fiber layer, (2) an elastic nonwoven fabric having a stretchable fiber layer integrated on both sides or one side of a net-like elastic sheet, (3) an elastic nonwoven fabric having a stretchable fiber layer integrated on both sides or one side of an elastic sheet made of an elastic film, and (4) an elastic nonwoven fabric having a large number of elastic filaments arranged so as to extend in one direction without crossing each other and integrated into a stretchable fiber layer. The "stretchable fiber layer" referred to here 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 water flow entangling or air through, or bonding them by heat embossing, adhesives, ultrasonic waves, etc. As the elastic fiber, a fiber made of 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 of a thermoplastic resin can be used.

[0026] The elastic nonwoven fabric of (4) above may be, for example, one having a structure in which a thread-like elastic filament is sandwiched between extensible fiber layers mainly made of inelastic fibers, and the layers are integrated together. Such an elastic nonwoven fabric is composed of two fiber sheets as fiber layers, and an elastic filament is interposed between the two sheets. This elastic nonwoven fabric can be produced, for example, according to the method described in JP 2009-61743 A.

[0027] In the elastic nonwoven fabric of (4), both of the two fiber sheets are stretchable. The two fiber sheets are stretchable in the same direction as the elastic filament. The stretchable form includes (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 by mechanical processing or the like causing fibers bonded at intersections to separate, or by structurally changing the three-dimensional structure formed by multiple fibers due to bonding between fibers, or by tearing off the constituent fibers. Examples of mechanical processing in (b) include heat treatment, inter-roll stretching, biting stretching by teeth or gears, and tensile stretching by a tenter.

[0028] In the stretchable nonwoven fabric of (4) above, the elastic filament can be formed by stretching the elastic resin in a molten or softened state. The multiple elastic filaments are each arranged continuously in one direction and extend in that one direction without crossing each other. The elastic filament is 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 filament in a state where the fibers are embedded in the elastic filament, and is not achieved 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 filament bonded thereto.

[0029] The two fiber sheets constituting the elastic nonwoven fabric of (4) can be various nonwoven fabrics such as air-through nonwoven fabric, heat roll nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, and meltblown nonwoven fabric. The two fiber sheets may be the same or different. Here, "same type of sheet" means sheets in which the manufacturing process of the sheet, the type of constituent fiber of the sheet, the fiber diameter and length of the constituent fiber, the thickness and basis weight of the sheet, etc. are all the same. When at least one of these is different, it is called "different type of sheet". In addition, the elastic filament is made of, for example, a thermoplastic elastomer or rubber. In particular, when a thermoplastic elastomer is used as a raw material, it is possible to melt-spin using an extruder like a normal thermoplastic resin, and the elastic filament obtained in this way is easy to heat-seal, so it is suitable for an elastic nonwoven fabric. From the viewpoint of further improving the fit to the wearer's body, the stretchable sheet arranged on the back side portion B of the exterior body 3 is preferably formed from the stretchable nonwoven fabric of (4) above. In this case, the extension direction of the elastic filaments of the stretchable sheet arranged on the back side portion B of the exterior body 3 coincides with the lateral direction Y.

[0030] The exterior body 3 has a non-stretchable region NE located between the front stretchable region FE and the rear stretchable region RE. The non-stretchable region NE in this embodiment is a region in the exterior body 3 that does not stretch in the lateral direction Y, and is a region in which no stretchable member such as the stretchable sheet described above is arranged. In this embodiment, only a non-stretchable sheet is arranged in the non-stretchable region NE. Specifically, the non-stretchable region NE is a region in which no outer layer sheet 31 is arranged, and only the inner layer sheet 33, which is a non-stretchable sheet, is arranged. In this embodiment, the non-elasticated region NE is located in the center of the front body F and the back body R in the longitudinal direction X, and is sandwiched in the longitudinal direction X between the front elasticated region FE and the back elasticated region RE.

[0031] A non-elastic sheet is a sheet that has substantially no elasticity in a certain direction, and in this embodiment, it is a sheet that has no elasticity at least in the horizontal direction Y, and preferably has no elasticity in either the vertical direction X or the horizontal direction Y. A sheet that has no elasticity means that the sheet hardly stretches even when a pulling force is applied to the sheet in the certain direction. For example, if a sample of a sheet having a length of 15 cm and a width of 5 cm is pulled in the longitudinal direction of the sample using a material tensile tester such as Tensilon, and the breaking elongation at the time the sample breaks is 10% or less, the sample has substantially no elasticity in the longitudinal direction. This breaking elongation can be calculated by (the sample length at break - the original length of the sample) / (the original length of the sample) x 100.

[0032] In this embodiment, the absorbent core 40 has a lower layer core 45 and an upper layer core 41 arranged on the skin-facing side of the lower layer core 45 (see Figs. 3 and 4). 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.

[0033] The lower core 45 of this embodiment has a long shape in the vertical direction X, similar to the absorbent body 4, and has an hourglass shape with both side edges at the center of the vertical direction X narrowed inward in the horizontal direction Y. The lower core 45 has a low-rigidity portion (hereinafter also referred to as a "lower-layer low-rigidity portion") 46 extending in the vertical direction X (see FIG. 1). The lower-layer low-rigidity portion 46 is disposed at a position spaced from both side edges along the vertical direction X of the upper core 41 toward the center. The lower-layer low-rigidity portion 46 of this embodiment is surrounded by the core-forming material of the lower core 45. The lower-layer low-rigidity portion 46 is a portion of the lower core 45 that has lower rigidity than other portions. For example, the lower-layer low-rigidity portion 46 is a low-basis weight portion in which the basis weight of the core-forming material forming the lower core 45 is lower than other portions, or a portion where the core-forming material is missing. The latter may be a slit (through hole) penetrating the lower core 45, or a recess with a bottom. The lower-layer low-rigidity portion 46 of this embodiment is a slit extending in the longitudinal direction X, and the basis weight of the material forming the absorbent core 40 (lower-layer core 45) is 0 g / m 2Such a configuration is preferable in terms of improving the fit of the diaper 1 and the underwear-like appearance (silhouette) described below. From the viewpoint of improving the conformability of the lower core 45 to the body, the lower low-rigidity portions 46 are preferably slits (through holes) extending in the longitudinal direction X. In the present embodiment, the lower core 45 has only one lower low-rigidity portion 46. Alternatively, the lower core 45 may have a plurality of lower low-rigidity portions 46.

[0034] The lower-layer low-rigidity portion 46 may have its entire length contained within the non-elastic region NE, or may have a portion extending from the non-elastic region NE. For example, the end of the lower-layer low-rigidity portion 46 on the ventral portion A side may extend into the front elastic region FE, and the end of the lower-layer low-rigidity portion 46 on the dorsal portion B side may be located in the non-elastic region NE. Alternatively, the end of the lower-layer low-rigidity portion 46 on the ventral portion A side may be located in the non-elastic region NE, and the end of the lower-layer low-rigidity portion 46 on the dorsal portion B side may extend into the rear elastic region RE. Alternatively, the end of the lower-layer low-rigidity portion 46 on the ventral portion A side may extend into the front elastic region FE, and the end of the lower-layer low-rigidity portion 46 on the dorsal portion B side may extend into the rear elastic region RE. From the viewpoint of providing the appearance of the diaper 1 when worn, particularly the appearance of the portion corresponding to the buttocks of the wearer with a neat silhouette like underwear, it is preferable that the end of the lower-layer low-rigidity portion 46 on the dorsal portion B side extends into the rear elastic region RE. In this embodiment, both ends of the lower-layer low-rigidity portion 46 in the longitudinal direction X are located in the non-elastic region NE.

[0035] The upper layer core 41 of this embodiment has a shape long in the vertical direction X, similar to the lower layer core 45. The upper layer core 41 has a substantially rectangular shape in a plan view. The upper layer core 41 has a low stiffness portion (hereinafter also referred to as "upper layer low stiffness portion") 42 extending in the vertical direction X. The upper layer low stiffness portion 42 is disposed at a position spaced from both side edges of the upper layer core 41 along the vertical direction X toward the center. The upper layer low stiffness portion 42 of this embodiment is surrounded by the core forming material of the upper layer core 41. The upper layer low stiffness portion 42 is a low basis weight portion in which the basis weight of the core forming material forming the upper layer core 41 is lower than other portions, or a portion where the core forming material is missing, and the same explanation as for the lower layer low stiffness portion 46 described above applies. From the viewpoint of further improving the ability of the upper layer core 41 to conform to the body, the upper layer low stiffness portion 42 is preferably a slit (through hole) extending in the vertical direction X. In this embodiment, the upper layer core 41 has only one upper layer low stiffness portion 42, but instead, the upper layer core 41 may have a plurality of upper layer low stiffness portions 42.

[0036] The lower layer core 45 has both ends in the horizontal direction Y extending from the edges of the upper layer core 41. Also, one end or both ends in the vertical direction X of the lower layer core 45 extend from the edges of the upper layer core 41. In this embodiment, both ends in the vertical direction X of the lower layer core 45 extend from the edges of the upper layer core 41. The lower layer core 45 has dimensions in the vertical direction X and horizontal direction Y larger than those of the upper layer core 41, and the upper layer core 41 is disposed such that the entire upper layer core 41 is located within a region inside the outer edge of the lower layer core 45 when viewed in a plan view. The ends of the lower core 45 in the lateral direction Y extend from the edges of the upper core 41 in the lateral direction Y, so that when the diaper 1 is worn, the portions 47a, 47b of the lower core 45 extending from the edges of the upper core 41 in the lateral direction Y (hereinafter also referred to as "lateral extensions") tend to bend toward the non-skin-facing surface side starting from the edges of the upper core 41 in the lateral direction Y. In other words, when viewed along the lateral direction Y, the absorbent body 4 tends to have a curved shape that is convex toward the skin-facing surface side.

[0037] Furthermore, because the ends of the lower core 45 in the longitudinal direction X extend from the edges of the upper core 41 in the longitudinal direction X, when the diaper 1 is worn, the portions 48a, 48b of the lower core 45 extending from the edges of the upper core 41 in the longitudinal direction X (hereinafter also referred to as "longitudinal extensions") tend to bend toward the skin-facing surface starting from the edges of the upper core 41 in the longitudinal direction X. In other words, when viewed along the longitudinal direction X, the absorbent body 4 tends to have a curved shape that is convex toward the non-skin-facing surface. In this way, the absorbent body 4 tends to have a curved shape that is convex toward the skin-facing side when viewed along the horizontal direction Y, and tends to have a curved shape that is convex toward the non-skin-facing side when viewed along the vertical direction X, so that the absorbent body 4 tends to deform to fit the shape of the wearer's buttocks when the diaper 1 is worn. Therefore, the diaper 1 of this embodiment provides an excellent wearing comfort, and the appearance of the diaper 1 when worn can have a neat silhouette like underwear (see FIG. 6(a)).

[0038] The lower core 45 extends from the upper core 41 on both sides in the longitudinal direction X, and the length in the longitudinal direction X of the longitudinal extension portion 48b on the back side B side may be the same as or different from the length in the longitudinal direction X of the longitudinal extension portion 48a on the ventral side A side. From the viewpoint of making it easier for the absorbent body 4 to deform along the shape of the wearer's buttocks when the diaper 1 is worn, it is preferable that the length in the longitudinal direction X of the longitudinal extension portion 48b on the back side B side is longer than that of the longitudinal extension portion 48b on the ventral side A side.

[0039] The lower core 45 extends from the upper core 41 on both sides in the lateral direction Y, and the length in the lateral direction Y of the lateral extension 47b on one side and the length in the lateral direction Y of the lateral extension 47a on the other side may be the same or different. From the viewpoint of making it easier for the absorbent body 4 to deform along the shape of the buttocks of the wearer when the diaper 1 is worn, it is preferable that the length in the lateral direction Y of the lateral extension 47b on one side and the length in the lateral direction Y of the lateral extension 47a on the other side are the same. When the length in the lateral direction Y of the lateral extensions 47a, 47b is not constant in the vertical direction X as in this embodiment, the length in the lateral direction Y of the lateral extensions 47a, 47b means the shortest length among the lengths from the edge in the lateral direction Y of the upper core 41 to the edge in the lateral direction Y of the lower core 45.

[0040] The diaper 1 has a low-stiffness overlapping region Kt where the upper low-stiffness portion 42 and the lower low-stiffness portion 46 overlap in a plan view. The upper low-stiffness portion 42 and the lower low-stiffness portion 46 may overlap such that the positions of the outer edges of the upper low-stiffness portion 42 and the lower low-stiffness portion 46 completely coincide in a plan view, or only a portion of the upper low-stiffness portion 42 and the lower low-stiffness portion 46 may overlap. The upper low-stiffness portion 42 and the lower low-stiffness portion 46 may overlap such that the entire upper low-stiffness portion 42 is located within a region surrounded by the outer edge of the lower low-stiffness portion 46, or vice versa. The lower low-stiffness portion 46 extends from an edge of the upper low-stiffness portion 42 in the longitudinal direction X. In this embodiment, the lower low-stiffness portion 46 extends from both ends of the upper low-stiffness portion 42 in the longitudinal direction X, but instead, it may extend from only one edge. The position of the side edge in the lateral direction Y of the lower low-rigidity portion 46 coincides with the position of the side edge in the lateral direction Y of the upper low-rigidity portion 42 .

[0041] Since the upper core 41 has the upper low-rigidity portion 42, the upper core 41 is easily bent in the vertical direction X at the upper low-rigidity portion 42. Since the lower core 45 has the lower low-rigidity portion 46, the lower core 45 is easily bent in the vertical direction X at the lower low-rigidity portion 46. Since the upper core 41 and the lower core 45 are easily bent in the vertical direction X, the absorbent body 4 is more easily curved in a convex shape toward the skin-facing surface side when viewed in the horizontal direction Y, and the wearing comfort and appearance of the diaper 1 can be further improved. Since the upper low-rigidity portion 42 and the lower low-rigidity portion 46 overlap each other in a plan view as in this embodiment, the absorbent body 4 is more easily bent in the vertical direction X at the portion where the upper low-rigidity portion 42 and the lower low-rigidity portion 46 overlap each other, and the wearing comfort and appearance of the diaper 1 can be further improved.

[0042] In the diaper 1, in a plan view, the core overlapping region Kc where the upper core 41 and the lower core 45 overlap with at least a part of the joining region S of the absorbent body 5 and the exterior body 3. The core overlapping region Kc and the joining region S may overlap so that the positions of the outer edges of both are completely aligned, or only a part of the core overlapping region Kc and the joining region S may overlap. The core overlapping region Kc and the joining region S may overlap so that the entire core overlapping region Kc is located within the region surrounded by the outer edge of the joining region S, or vice versa. In this embodiment, a part of the core overlapping region Kc and a part of the joining region S overlap. Specifically, the core overlapping region Kc and the central joining region Sc overlap. The central joining region Sc extends from the edge of the core overlapping region Kc in the vertical direction X. The core overlapping region Kc extends from the edge of the central joining region Sc in the horizontal direction Y.

[0043] Since the core overlapping region Kc and the bonding region S overlap, when the absorbent 4, particularly the lower core 45, is bent from an edge of the upper core 41 toward the skin-facing side or the non-skin-facing side, the exterior body 3 deforms in accordance with the movement of the absorbent 4. Therefore, the exterior body 3 also deforms in accordance with the shape of the buttocks of the wearer of the diaper 1, further improving the appearance of the diaper 1. From the viewpoint of achieving this effect more significantly, it is preferable that the core overlapping region Kc and the bonding region S overlap when the diaper 1 is in an unfolded and stretched state, and it is more preferable that they overlap when the diaper 1 is in its natural state and when the diaper 1 is in its unfolded and stretched state.

[0044] From the viewpoint of making the exterior body 3 easily deformable along the shape of the buttocks of the wearer of the diaper 1 and further improving the appearance of the diaper 1, it is preferable that the low-rigidity overlapping region Kt, in which the upper low-rigidity portion 42 and the lower low-rigidity portion 46 of the core overlapping region Kc overlap, overlaps at least a part of the joining region S. The low-rigidity overlapping region Kt and the joining region S may overlap so that the positions of the outer edges of both completely coincide with each other, or only a part of the low-rigidity overlapping region Kt and the joining region S may overlap. In addition, the low-rigidity overlapping region Kt and the joining region S may overlap so that the entire low-rigidity overlapping region Kt is located within the region surrounded by the outer edge of the joining region S, or vice versa. In this embodiment, a part of the low-rigidity overlapping region Kt and a part of the joining region S overlap. Specifically, both overlap so that the low-rigidity overlapping region Kt is included in the central joining region Sc. In order to further improve the appearance of the diaper 1, it is preferable that the low stiffness overlap region Kt and the joining region S overlap when the diaper 1 is in an unfolded and stretched state, and it is even more preferable that they overlap both when the diaper 1 is in its natural state and when the diaper 1 is in its unfolded and stretched state.

[0045] Furthermore, in the diaper 1, the stretchable sheet overlaps at least a portion of the lower core 45 in the back portion B. In this embodiment, a portion of the rear outer sheet 31b, which is a stretchable sheet, overlaps with a portion of the lower core 45. In this specification, the expression that two objects, such as a stretchable sheet and at least a portion of the lower core 45, overlap includes both a case where one object directly overlaps the other and a case where they do not directly overlap. Specifically, the end of the rear outer sheet 31b on the crotch C side in the central region in the transverse direction Y overlaps with the end of the lower core 45 on the back B side. The overlapping of the elastic sheet and the lower core 45 allows the lower core 45 and the wide areas on both sides of it to fit the wearer's body as a surface due to the contractile force of the elastic sheet stretched when the diaper 1 is worn, and the fit is maintained well while the diaper 1 is worn as the elastic sheet repeatedly stretches. This further improves the wearing comfort of the diaper 1 and makes it easier for the diaper 1 to have a neat silhouette like underwear when worn. From the viewpoint of further improving the wearing comfort and appearance of the diaper 1, it is preferable that the elastic sheet and the lower core 45 overlap when the diaper 1 is in an unfolded and stretched state, and it is more preferable that the elastic sheet and the lower core 45 overlap when the diaper 1 is in a natural state and when the diaper 1 is in an unfolded and stretched state. Thus, the diaper 1 of the present embodiment is excellent in fit and appearance when worn.

[0046] In this embodiment, when the diaper 1 is worn, the skin-facing surface of the diaper 1 has a saddle-shaped curved surface P. Fig. 7 shows a schematic diagram of the skin-facing surface of the diaper 1 when worn. The "saddle-shaped curved surface" refers to a curved surface that is convexly curved toward the skin-facing surface side when viewed along the transverse direction Y (see Figs. 7(a) and (b)), and that is convexly curved toward the non-skin-facing surface side when viewed along the longitudinal direction X (see Figs. 7(a) and (c)). When the diaper 1 is worn, the skin-facing surface of the diaper 1 has a saddle-shaped curved surface (hereinafter also referred to as "saddle-shaped curved surface") P, which allows the diaper 1 to easily deform to conform to the shape of the wearer's buttocks, thereby further improving the wearing comfort and appearance of the diaper 1. From the viewpoint of achieving this effect more significantly, it is preferable that when the diaper 1 is worn, the saddle-shaped curved surface P extends toward the back side portion B in the longitudinal direction X beyond the gluteal sulcus Q of the wearer (see FIG. 6(b)).

[0047] In the diaper 1, it is preferable that the distance between the end edge in the longitudinal direction X of the upper core 41 and the low-rigidity overlapping region Kt is short. This point will be described below. The end edge in the longitudinal direction X of the upper core 41 is a portion that becomes the starting point when the absorbent 4 bends along the transverse direction Y. The low-rigidity overlapping region Kt is a portion that becomes the starting point when the absorbent 4 bends along the longitudinal direction X. Since the distance between the end edge in the longitudinal direction X of the upper core 41 and the low-rigidity overlapping region Kt is short, the starting point when bending along the transverse direction Y and the starting point when bending along the longitudinal direction X can be brought closer to each other, so that the saddle-shaped curved surface P can be more easily formed when the diaper 1 is worn. From the viewpoint of achieving this effect more significantly, it is preferable that the length L1 in the longitudinal direction X of the low-rigidity overlapping region Kt is longer than either of the following distances (1) and (2). (1) Distance L2 from the edge of the abdominal side portion A of the upper core 41 in the longitudinal direction X to the edge of the abdominal side portion A of the upper low-rigidity portion 42 in the longitudinal direction X (2) Distance L3 from the edge of the back side portion B of the upper core 41 in the longitudinal direction X to the edge of the back side portion B of the upper low-rigidity portion 42 in the longitudinal direction X

[0048] The ratio L2 / L1 of the distance L2 to the length L1 is preferably 0.9 or less, and more preferably 0.8 or less. The ratio L3 / L1 of the distance L3 to the length L1 is preferably 0.9 or less, and more preferably 0.8 or less. The distance L2 and the distance L3 may be the same or different. Furthermore, the distance L2 or the distance L3 may be zero.

[0049] The lower-layer low-rigidity portion 46 does not have to extend from the upper-layer core 41 in the longitudinal direction X, but preferably does. By having the lower-layer low-rigidity portion 46 extend from the upper-layer core 41 in the longitudinal direction X, the lower-layer low-rigidity portion 46, which is the starting point when the absorbent 4 bends along the longitudinal direction X, overlaps with the end edge in the longitudinal direction X of the upper core 41, which is the starting point when the absorbent 4 bends along the transverse direction Y, and this makes it easier to form a saddle-shaped curved surface P. From the viewpoint of making it easier to form the saddle-shaped curved surface P on the back side B side and further improving the wearing comfort and appearance of the back side B side, it is preferable that the lower-layer low-rigidity portion 46 extends from the upper core 41 at least on the back side in the longitudinal direction X. From the viewpoint of further improving the wearing comfort and appearance of the diaper 1, it is preferable that the lower-layer low-rigidity portion 46 extends from the upper core 41 on both sides in the longitudinal direction X. In this embodiment, the rear end of the lower low-rigidity portion 46 on the dorsal portion B side in the longitudinal direction X extends further toward the dorsal portion B than the rear end of the dorsal portion B side in the longitudinal direction X of the upper core 41. Also, the rear end of the lower low-rigidity portion 46 on the ventral portion A side in the longitudinal direction X extends further toward the ventral portion A than the rear end of the ventral portion A side in the longitudinal direction X of the upper core 41.

[0050] The ratio L4 / L of the length L4 of the extension portion of the lower low-rigidity portion 46 from the edge of the back portion B in the longitudinal direction X of the upper core 41 to the total length L of the absorbent body 4 in the longitudinal direction X is preferably 0.03 or more, and more preferably 0.08 or more, from the viewpoint of ensuring that the bent portions in the absorbent body 4 along the longitudinal direction X and the bent portions in the transverse direction Y intersect with each other and facilitating the formation of the saddle-shaped curved surface P.

[0051] The ratio L5 / L of the length L5 of the extension portion of the lower low-rigidity portion 46 from the edge of the ventral portion B in the longitudinal direction X of the upper core 41 to the total length L in the longitudinal direction X of the absorbent body 4 is preferably 0.03 or more, and more preferably 0.08 or more, from the viewpoint of ensuring that the bent portions in the longitudinal direction X and the bent portions in the transverse direction Y in the absorbent body 4 intersect reliably and making it easy to form the saddle-shaped curved surface P. The length L4 and the length L5 may be the same or different.

[0052] In the diaper 1, it is preferable that, in a plan view, the stretchable sheet overlaps with the upper low stiffness portion 42 or the lower low stiffness portion 46. This allows the stretchable sheet to stretch in the lateral direction Y, and makes it easier for the absorbent body 4 to bend in the longitudinal direction X starting from the upper low stiffness portion 42 or the lower low stiffness portion 46. From the viewpoint of further improving the wearing comfort and appearance of the diaper 1, it is more preferable that the stretchable sheet overlaps with the lower low stiffness portion 46.

[0053] It is preferable that, when the diaper 1 is worn, the upper-layer low-rigidity portion 42 or the lower-layer low-rigidity portion 46 extends toward the back side portion B in the longitudinal direction X further than the gluteal sulcus Q of the wearer. This allows the diaper 1 to fit the wearer's gluteal cleft better, thereby further improving the wearing comfort and appearance of the diaper 1. From the viewpoint of achieving this effect more significantly, it is more preferable that the lower-layer low-rigidity portion 46 extends toward the back side portion B in the longitudinal direction X further than the gluteal sulcus Q of the wearer.

[0054] In the diaper 1, it is preferable that the joining region S overlaps the entire area in the longitudinal direction X of the upper core 41 in a plan view. This allows the exterior body 3 to more easily follow the movement of the absorbent body 4, further improving the appearance of the diaper 1. In addition, since the exterior body 3 is joined to the absorbent main body 5 at the edge position in the longitudinal direction X of the upper core 41, which is the starting point for bending the absorbent body 4 along the transverse direction Y, it is more easy to form a saddle-shaped curved surface P when the diaper 1 is worn.

[0055] Next, a description will be given of the materials forming each part of the diaper 1. As the inner layer sheet 33 and the fixing sheet 35, various materials conventionally used as exterior bodies in this type of absorbent article can be used without any particular restrictions. For example, as the inner layer sheet 33, nonwoven fabrics produced by various manufacturing methods such as spunbond nonwoven fabric, air-through nonwoven fabric, needle punch nonwoven fabric, etc. can be used.

[0056] The elastic members 32, 37, 61, 63 such as the leg elastic members are preferably made of elastic materials such as natural rubber, polyurethane resin, urethane foam resin, and hot melt elastic members formed into threads (rubber threads) or bands (rubber strips). The top sheet 12 may be made of various nonwoven fabrics or perforated films, and the leak-proof sheet 13 may be made of a resin film or a laminate of a resin film and a nonwoven fabric.

[0057] The absorbent core 40 of the absorbent body 4 is formed from core-forming materials such as hydrophilic fibers such as cellulose including pulp, and water-absorbent polymers. The absorbent core 40 is composed of, for example, a pile of hydrophilic fibers, a mixed pile of the hydrophilic fibers and water-absorbent polymers, a pile of water-absorbent polymers, a laminated structure in which water-absorbent polymers are supported between two water-absorbent sheets, or the like. The core wrap sheet 49 may be, for example, tissue paper made of hydrophilic fibers or liquid-permeable nonwoven fabric.

[0058] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0059] 1. Pants-type disposable diapers (diapers) 3 Exterior body 4. Absorber 5 Absorbent body 6 Leak proof cuff 12 Surface sheet 13 Leak-proof sheet 31 Outer layer sheet 32 Waist elastic member 33 Inner sheet 34 End fixing sheet 35 Fixing sheet 37 Leg elastic member 40 Absorbent Core 41 Upper Core 42 Upper layer low rigidity part 45 Lower Core 46 Lower layer low rigidity part 48 Intermediate elastic member 49 Core wrap sheet 60 Cuff forming sheet 61 Cuff elastic member A Ventral part B Dorsal part C Inseam F Front R Back Kc core overlap region Kt Low stiffness overlap area S junction area X vertical direction Y Horizontal

Claims

1. An absorbent main body having a ventral part arranged on the ventral side of the wearer, a dorsal part arranged on the dorsal side of the wearer, and a crotch part located between the ventral part and the dorsal part, and having an absorber containing an absorbent core, and an outer wrapper arranged on the non-skin-facing surface side of the absorbent main body, having a longitudinal direction extending from the ventral part through the crotch part to the dorsal part and a transverse direction orthogonal to the longitudinal direction, and being divided into a front body part arranged on the ventral side of the wearer and a back body part arranged on the dorsal side of the wearer with the center of the longitudinal direction as a boundary when worn, and being a pant-type disposable diaper having a waist opening and a pair of leg openings, wherein the absorbent core has a lower layer core and an upper layer core arranged on the skin-facing surface side of the lower layer core, and both end portions in the transverse direction and one end portion or both end portions in the longitudinal direction of the lower layer core extend from the edge of the upper layer core, each of the upper layer core and the lower layer core has a low-rigidity portion extending in the longitudinal direction at a position spaced apart from the center side from both side edges along the longitudinal direction of the upper layer core, the outer wrapper has an elastic sheet having elasticity in the transverse direction on the dorsal part, in a plan view, there is a low-rigidity portion overlapping region where the low-rigidity portion of the upper layer core and the low-rigidity portion of the lower layer core overlap, the low-rigidity portion overlapping region overlaps at least a part of the joining region of the absorbent main body and the outer wrapper, and in the dorsal part, the elastic sheet and at least a part of the lower layer core overlap, a disposable diaper.

2. The disposable diaper according to claim 1, wherein in a worn state, the skin-facing surface of the disposable diaper has a saddle-shaped curved surface.

3. The disposable diaper according to claim 2, wherein when the disposable diaper is worn, the curved surface extends to the dorsal part side in the longitudinal direction more than the gluteal groove of the wearer.

4. The disposable diaper according to claim 1 or 2, wherein the length of the low-rigidity portion overlapping region in the longitudinal direction is longer than either of the following distances (1) and (2). (1) The distance from the edge on the ventral side in the longitudinal direction of the upper core to the edge on the ventral side in the longitudinal direction of the low-rigidity portion of the upper core (2) The distance from the edge on the dorsal side in the longitudinal direction of the upper core to the edge on the dorsal side in the longitudinal direction of the low-rigidity portion of the upper core

5. The rear end on the dorsal side in the longitudinal direction of the low-rigidity portion of the lower core extends more toward the dorsal side than the rear end on the dorsal side in the longitudinal direction of the upper core. The disposable diaper according to claim 1 or 2.

6. In plan view, the stretchable sheet overlaps with the low-rigidity portion of the upper core or the low-rigidity portion of the lower core. The disposable diaper according to claim 1 or 2.

7. When the disposable diaper is worn, the low-rigidity portion of the upper core or the low-rigidity portion of the lower core extends more toward the dorsal side in the longitudinal direction than the gluteal groove of the wearer. The disposable diaper according to claim 1 or 2.

8. In plan view, the joining region overlaps with the entire longitudinal direction of the upper core. The disposable diaper according to claim 1 or 2.

9. The low-rigidity portion of the upper core or the low-rigidity portion of the lower core consists of slits. The disposable diaper according to claim 1 or 2.

Images