Underpants-type absorbent article

Abstract

This underpants-type absorbent article (1) has crotch elastic members (40) that are provided more on the non-skin side than an absorbent core (11) and expand / contract along the longitudinal direction. At least a part of the crotch elastic members (40) are arranged in a central region among three equal regions obtained by trisecting the absorbent core (11) in the left-right direction. The absorbent core 11 has a crotch region and a one-side end region that overlaps, in the longitudinal direction, a waist joint part (2) on one side in the longitudinal direction. A high-density region (11H) in which the average density of a highly absorbent polymer is higher than the average density of the highly absorbent polymer in the one-side end region is arranged in the crotch region, and the high-density region (11H) has a portion overlapping the crotch elastic members (40) in the longitudinal direction.

Description

Pants-type absorbent article

[0001] The present invention relates to a pants-type absorbent article.

[0002] In the disposable wearing article disclosed in Patent Document 1, an absorbent sheet having an absorbent polymer sandwiched between liquid-permeable sheets is arranged in the buttocks region. By concentrating the absorbent polymer in the rear waist region in this way to increase the absorption capacity, leakage from the rear waist region, which is common when sitting or lying down, can be reduced.

[0003] Patent No. 5848068

[0004] However, compared with wearers of tape-type absorbent articles, wearers of pant-type absorbent articles spend less time lying down and more time walking or standing. Furthermore, pant-type absorbent articles are often used in conjunction with toileting, and the wearer's excretion volume may be smaller than that of tape-type absorbent articles. Therefore, even if absorbent polymer is concentrated in the rear waistband region of a pant-type absorbent article as in Patent Document 1, the excreted liquid is absorbed in the urination region and does not spread to the back, making it difficult to achieve the effects of the absorbent polymer. In particular, Patent Document 1 provides the absorbent body with slits or low-basis-weight regions extending from the urination region to the buttocks region as guides to guide urine to an absorbent sheet spaced from the urination region. This reduces the absorption capacity of the urination region, which receives urine, and urine may leak before being guided to the absorbent sheet. Furthermore, in Patent Document 1, when the absorbent sheet becomes heavy due to the absorption of liquid, the rear leg-hole elastic members arranged in the rear waistband region and stretching in the front-to-rear direction provide a lifting effect to prevent the absorbent body from separating from the skin. However, the rear leg-hole elastic members are arranged outboard of the absorbent body in the width direction, making it difficult to obtain a sufficient lifting effect, and there is a risk of the absorbent article (absorbent body) sagging. Furthermore, even if a stretchable member is arranged so as to overlap the absorbent body continuously with a pair of widthwise leg-hole elastic members, the stretchable member stretches in the width direction, making it difficult to obtain a sufficient lifting effect compared to a stretchable member that stretches in the up-down direction.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a pants-type absorbent article that suppresses leakage of excrement while also preventing it from sagging from the crotch area of ​​the wearer even after excretion.

[0006] The main invention for achieving the above object is a pants-type absorbent article comprising an exterior member and an absorbent main body having an absorbent core, the absorbent core comprising a highly absorbent polymer, a ventral waist portion and a rear waist portion of the exterior member joined in an annular shape by a pair of waist joints, the article having, in an unfolded and stretched state, longitudinal, left-right and thickness directions which intersect with one another, and crotch elastic members which are provided on the side away from the skin than the absorbent core and stretch along the longitudinal direction, at least a part of the crotch elastic members being arranged in a central region of three regions obtained by dividing the absorbent core into thirds in the left-right direction as viewed in the thickness direction, the absorbent core having a crotch region located closer to the center in the longitudinal direction than the pair of waist joints, and one side end region which overlaps in the longitudinal direction with the waist joint on one side of the longitudinal direction, The present invention provides a pants-type absorbent article, characterized in that the crotch region has at least one high-density region in which the average density of the superabsorbent polymer is higher than the average density of the superabsorbent polymer in the one side end region, and the high-density region has a portion that overlaps with the crotch elastic member in the longitudinal direction. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0007] According to the present invention, it is possible to provide a pants-type absorbent article that suppresses leakage of excrement and also suppresses sagging from the crotch area of ​​the wearer even after excretion.

[0008] 1 is a schematic front view of a pants-type disposable diaper 1. It is a schematic plan view of the diaper 1 in an unfolded and stretched state, as seen from the skin side. It is a schematic cross-sectional view taken along line CC in FIG. 2. It is a schematic cross-sectional view of the absorbent main body 10. It is an explanatory diagram of the arrangement of the high-density region 11H of the absorbent core 11 and the crotch elastic member 40 in the first embodiment. It is an explanatory diagram of the arrangement of the high-density region 11H of the absorbent core 11 and the crotch elastic member 40 in the first embodiment. FIG. 7A is a schematic cross-sectional view of the ventral end region 11EA and the dorsal end region 11EB of the absorbent core 11, and FIG. 7B is a schematic cross-sectional view of the crotch region 11C of the absorbent core 11. FIGS. 8A and 8B are explanatory views of modified examples of the absorbent core 11. FIGS. 9A and 9B are explanatory views of modified examples of the absorbent core 11. FIGS. 10A and 10B are explanatory views of an absorbent core 71 in a second embodiment. 11A and 11B are explanatory diagrams of an absorbent core 71 of the second embodiment.

[0009] The present specification and the accompanying drawings make clear at least the following: (Aspect 1) A pants-type absorbent article comprising an exterior member and an absorbent main body having an absorbent core, the absorbent core containing a superabsorbent polymer, a ventral waist portion and a rear waist portion of the exterior member joined in an annular shape by a pair of waist-line joining portions, the article having a longitudinal direction, a left-right direction, and a thickness direction that intersect with one another in an unfolded and stretched state, and a crotch elastic member that is provided on the farther side from the skin than the absorbent core and stretches along the longitudinal direction, and the absorbent core is divided into three equal parts in the left-right direction when viewed in the thickness direction, and at least one elastic member is provided in a central region of three regions. a crotch elastic member disposed on one side of the absorbent core, the crotch elastic member being located on the other side of the absorbent core in the longitudinal direction; a crotch region located closer to the center of the longitudinal direction than the pair of waistline joints; and a one-side end region overlapping in the longitudinal direction with the waistline joint on one side of the longitudinal direction; the crotch region is provided with at least one high-density region in which the average density of the superabsorbent polymer is higher than the average density of the superabsorbent polymer in the one-side end region; and the high-density region has a portion overlapping in the longitudinal direction with the crotch elastic member.

[0010] According to Aspect 1, the absorption capacity (water retention) of the crotch region of the absorbent core is increased, allowing the superabsorbent polymer to efficiently absorb and retain excretory fluid directly received by the crotch region from the wearer's excretory opening, thereby preventing leakage of excretory fluid. Even if the high-density region of superabsorbent polymer absorbs excretory fluid and swells, increasing the weight of the crotch region, the crotch region is lifted by the crotch elastic members located in the crotch region. Therefore, sagging of the absorbent article (absorbent core) from the wearer's crotch area after excretion is prevented. Furthermore, by not increasing the density of the superabsorbent polymer in one end region more than necessary, the graininess of the superabsorbent polymer can be reduced, reducing discomfort during wear. Furthermore, there is no need to increase the basis weight of the liquid-absorbent fiber to reduce the graininess. This also prevents the increase in the thickness of the absorbent core due to an increase in the basis weight of the liquid-absorbent fiber, thereby reducing stiffness during wear. Other advantages include reduced manufacturing costs and ensuring the diffusion of excretory fluid and the ability to draw it into the absorbent core.

[0011] (Aspect 2) The pants-type absorbent article according to Aspect 1, wherein in the unfolded and stretched state, the high-density region has a portion that overlaps with the crotch elastic member in the thickness direction.

[0012] According to Aspect 2, even if the high-density region of the absorbent polymer absorbs excrement and becomes heavier, the high-density region is directly pulled up by the crotch elastic members, thereby further preventing the absorbent article (absorbent core) from sagging from the crotch area of ​​the wearer.

[0013] (Aspect 3) A pants-type absorbent article as described in Aspect 1 or 2, wherein, in an unfolded and stretched state, the absorbent core has an other-side end region that overlaps in the longitudinal direction with the waistband joint on the other side of the longitudinal direction, and the average density of the superabsorbent polymer in the high-density region is higher than the average density of the superabsorbent polymer in the other-side end region.

[0014] According to the third aspect, the absorbent core's crotch region has a reliably increased absorption capacity, further suppressing leakage of excrement. Furthermore, by not increasing the density of the superabsorbent polymer in the other end region more than necessary, the graininess of the superabsorbent polymer can be reduced. Furthermore, since there is no need to increase the basis weight of the liquid-absorbent fiber to reduce the graininess, stiffness during wear can be reduced. Furthermore, manufacturing costs can be reduced, and excrement can be dispersed and drawn into the absorbent core.

[0015] (Aspect 4) The pants-type absorbent article according to any one of Aspects 1 to 3, wherein in the unfolded and stretched state, a plurality of the high-density regions are arranged at intervals in the planar direction in the crotch region.

[0016] According to the fourth aspect, excrement can be absorbed and retained in the high-density regions while being dispersed between the high-density regions, and the absorbent core can be effectively utilized in the planar direction.

[0017] (Aspect 5) A pants-type absorbent article according to any one of aspects 1 to 4, which, in an unfolded and stretched state, has a crotch elastic region defined by the stretchable portion of the crotch elastic member, and the left-right length of the high-density region is longer than the left-right length of the crotch elastic region.

[0018] According to Aspect 5, the absorbency of the crotch region is increased across a wide area in the left-right direction, further reducing leakage of excrement. Meanwhile, the crotch elastic members prevent the absorbent core from being pulled up across a wide area in the left-right direction. This ensures sufficient space to accommodate excrement and reduces overflow and leakage.

[0019] (Aspect 6) A pants-type absorbent article according to any one of Aspects 1 to 5, wherein in an unfolded and stretched state, the absorbent core has a fiber layer containing liquid-absorbent fibers, a first sheet portion, and a second sheet portion, and when a sheet member in which the superabsorbent polymer is sandwiched between the first sheet portion and the second sheet portion in the thickness direction is defined as a superabsorbent polymer sheet, the superabsorbent polymer sheet has a placement area in which the superabsorbent polymer is placed, and in the high-density area, the placement area of ​​the superabsorbent polymer sheet and the fiber layer are stacked in the thickness direction.

[0020] According to the sixth aspect, a high density region of superabsorbent polymer can be arranged in the crotch region.

[0021] (Aspect 7) A pants-type absorbent article as described in Aspect 6, wherein, in the unfolded and stretched state, the superabsorbent polymer sheet is positioned closer to the skin in the thickness direction than the fiber layer, and multiple high-density regions are arranged at intervals in the planar direction.

[0022] According to Aspect 7, the superabsorbent polymer sheet located on the skin side absorbs not only excreted liquid but also moisture and sweat of the wearer, improving the dryness inside the absorbent article. Furthermore, even if the high-density areas of the superabsorbent polymer on the skin side absorb excreted liquid and swell, the areas between the high-density areas can draw the excreted liquid into the absorbent core.

[0023] (Aspect 8) The pants-type absorbent article according to Aspect 6, wherein in the unfolded and stretched state, the superabsorbent polymer sheet is disposed closer to the non-skin side in the thickness direction than the fiber layer.

[0024] According to the eighth aspect, the swollen superabsorbent polymer does not crowd on the skin side, ensuring the ability to draw excreted liquid into the absorbent core, thereby enabling the absorbent core to be used effectively in the thickness direction.

[0025] (Aspect 9) A pants-type absorbent article described in any of aspects 1 to 5, wherein, in an unfolded and stretched state, the absorbent core has an aggregate of liquid-absorbent fibers, and the superabsorbent polymer is mixed into the aggregate, and the average density of the superabsorbent polymer mixed into the aggregate in the high-density region is higher than the average density of the superabsorbent polymer mixed into the aggregate in the one-side end region.

[0026] According to Aspect 9, a high density region of superabsorbent polymer can be arranged in the crotch region.

[0027] (Aspect 10) A pants-type absorbent article according to any one of aspects 1 to 9, wherein in the unfolded and stretched state, at least a portion of the high-density region is located closer to the ventral side than the longitudinal center of the pants-type absorbent article.

[0028] According to Aspect 10, the high-density region is more likely to directly receive excretory fluid from the urethral opening, and the excretory fluid is absorbed and retained by the superabsorbent polymer, thereby further suppressing leakage of excretory fluid. Furthermore, compared with wearers of tape-type absorbent articles, wearers of pants-type absorbent articles spend less time lying down and more time walking and maintaining an upright position, so excretory fluid may not spread to the dorsal side. Therefore, by positioning the high-density region on the ventral side, the high-density region can be effectively utilized.

[0029] (Aspect 11) A pants-type absorbent article as described in Aspect 10, wherein, in an unfolded and stretched state, at least a portion of the area where the high-density region overlaps with the crotch elastic member in the longitudinal direction is located closer to the ventral side than the center of the pants-type absorbent article in the longitudinal direction.

[0030] According to Aspect 11, the high-density region is more likely to receive excreted fluid directly from the urethral opening, and the excreted fluid is absorbed and retained by the superabsorbent polymer, thereby further suppressing leakage of excreted fluid. In addition, the superabsorbent polymer that swells upon receiving excreted fluid directly from the urethral opening is pulled up by the crotch elastic members, which are positioned in the same longitudinal direction, thereby further suppressing sagging of the absorbent core.

[0031] (Aspect 12) A pants-type absorbent article according to any one of aspects 1 to 11, having a urination area that contacts the wearer's urination area when in an unfolded and stretched state, and at least a portion of the overlapping portion of the high-density area with the crotch elastic member in the longitudinal direction is located in the urination area.

[0032] According to Aspect 12, the high-density region is more likely to receive excreted fluid directly from the urethral opening, and the excreted fluid is absorbed and retained by the superabsorbent polymer, thereby further suppressing leakage of excreted fluid. In addition, the superabsorbent polymer that swells upon receiving excreted fluid directly from the urethral opening is pulled up by the crotch elastic members, which are positioned in the same longitudinal direction, thereby further suppressing sagging of the absorbent core.

[0033] (Aspect 13) A pants-type absorbent article according to any one of aspects 1 to 12, wherein in the unfolded and stretched state, the high-density region is located closer to the center of the longitudinal direction than the waistline joint on the ventral side of the longitudinal direction.

[0034] According to Aspect 13, by not extending the high-density region toward the ventral side more than necessary, the grainy feeling caused by the superabsorbent polymer can be reduced, and since there is no need to increase the basis weight of the liquid absorbent fiber to reduce the grainy feeling, the stiffness during wear can be reduced. In addition, it is possible to reduce manufacturing costs and ensure the diffusion of excreted liquid and the ability to draw it into the absorbent core.

[0035] ===Embodiments=== The following describes a pants-type disposable diaper for adults (hereinafter also referred to as "diaper 1") as an example of a pants-type absorbent article according to an embodiment of the present invention. However, pants-type absorbent articles according to the present invention can also be used as sanitary shorts, etc. Furthermore, the wearer may be a living organism such as an infant or an animal.

[0036] <<Basic Structure of Pants-Type Disposable Diaper 1>> Fig. 1 is a schematic front view of the pants-type disposable diaper 1. Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state, as seen from the skin side. Fig. 3 is a schematic cross-sectional view taken along line CC in Fig. 2. Fig. 4 is a schematic cross-sectional view of the absorbent main body 10. Here, the "unfolded state" of the diaper 1 refers to a state in which the waist seam 2, which will be described later, has been untied, the diaper 1 has been opened in the longitudinal direction, and the diaper 1 has been unfolded in a plane.

[0037] In the pants-type state shown in Figure 1, the diaper 1 has a vertical direction, a horizontal direction, and a front-to-back direction, which intersect with one another, and is formed with a waist opening BH and a pair of leg openings LH. In the unfolded state shown in Figure 2, the diaper 1 has a longitudinal direction, a horizontal direction, and a thickness direction, which intersect with one another. The longitudinal direction is the vertical direction in the pants-type state. The thickness direction is the direction in which the components constituting the diaper 1 are stacked. In the vertical direction, the waist opening BH side is the upper side, and the crotch side is the lower side. In the front-to-back direction, the side facing the wearer's stomach is the front side, and the side facing the wearer's back is the rear side. In the thickness direction, the side in contact with the wearer's body (skin) is the skin side, and the opposite side is the non-skin side.

[0038] Furthermore, the "stretched state" of the diaper 1 refers to a state in which the entire diaper 1 is stretched without wrinkles by stretching each of the elastic members of the diaper 1 (e.g., the waist elastic members 24, 25 and the leak-proof wall elastic member 51, which will be described later), specifically, a state in which the dimensions of each of the materials constituting the diaper 1 (e.g., the top sheet 12 and the inner layer sheet 23, which will be described later) are stretched to the same dimensions as or close to the dimensions of the individual members.

[0039] 3, the diaper 1 includes an outer cover member 20 and an absorbent main body 10 joined to the skin side of the outer cover member 20. Cover sheets 31, 32 may be provided to cover both longitudinal ends of the absorbent main body 10 from the skin side. This can prevent the edges of the absorbent main body 10 from digging into the wearer's body and prevent the absorbent main body 10 from opening open.

[0040] The diaper 1 in an unfolded state is folded in half at a longitudinal center position CL, and the ventral waist portion 20A and the dorsal waist portion 20B of the outer cover member 20 are joined together in an annular shape by a pair of waist seam portions 2, thereby forming the pants-type diaper 1 shown in Fig. 1. Examples of joining methods for the waist seam portions 2 include welding and joining with an adhesive.

[0041] As shown in Figure 4, the absorbent body 10 includes an absorbent core 11 that absorbs excretory liquid, a liquid-permeable top sheet 12 (e.g., nonwoven fabric) provided on the skin side of the absorbent core 11 in the thickness direction, a liquid-impermeable back sheet 13 (e.g., a resin film such as polyethylene or polypropylene) provided on the non-skin side of the absorbent core 11 in the thickness direction, a pair of side sheets 16, and an elastic member cover sheet 17. The elastic member cover sheet 17 is a sheet member that covers the non-skin side of the crotch elastic members 40 that stretch in the longitudinal direction. The pair of side sheets 16 and the elastic member cover sheet 17 may be formed from a single sheet. In other words, a single sheet may cover the non-skin side of the back sheet 13 and the crotch elastic members 40 from the non-skin side.

[0042] The absorbent core 11 absorbs and retains excreted liquids such as urine. The surface of the absorbent core 11 may be covered with a liquid-permeable core wrap sheet 18 (e.g., tissue paper). The absorbent core 11 contains a super absorbent polymer (SAP). The super absorbent polymer is not particularly limited as long as it can be used as an absorbent core for an absorbent article, and examples include starch-based, cellulose-based, and synthetic polymer-based polymer absorbents. Furthermore, although the absorbent core 11 of this embodiment has a shape in which the center portion in the longitudinal direction is narrowed inward in the left-right direction, the planar shape of the absorbent core 11 is not particularly limited.

[0043] A pair of leakage prevention walls 50 are provided along the longitudinal direction on both left-right sides of the absorbent body 10. As shown in FIG. 4 , portions of the side sheets 16 extending from both left-right sides of the non-skin side of the back sheet 13 are folded at multiple locations to form the leakage prevention walls 50 on both left-right sides of the skin side of the top sheet 12. Leakage prevention wall elastic members 51 (e.g., thread-like elastic members) are attached to the leakage prevention walls 50 in a stretched state along the longitudinal direction. The stretchability of the leakage prevention wall elastic members 51 allows the leakage prevention walls 50 to stand up toward the wearer's skin, thereby blocking excrement. Furthermore, leg-hole elastic members 52 (e.g., thread-like elastic members) are attached to the side sheets 16 in a stretched state along the longitudinal direction, laterally outboard of the leakage prevention wall elastic members 51.

[0044] The outer covering member 20 is a sheet member having a shape in which the longitudinal center portion is constricted inward in the left-right direction. As shown in Fig. 3, the outer covering member 20 has a ventral outer layer sheet 21, a dorsal outer layer sheet 22, an inner layer sheet 23, waist elastic members 24, 25, and a buttocks elastic member 26. Of the outer covering member 20, the portion overlapping with the ventral waist joint 2 in the longitudinal direction is also referred to as a ventral waist portion 20A, and the portion overlapping with the dorsal waist joint 2 in the longitudinal direction is also referred to as a dorsal waist portion 20B.

[0045] The ventral outer layer sheet 21, the dorsal outer layer sheet 22, and the inner layer sheet 23 can be exemplified by flexible sheet members such as nonwoven fabrics. The inner layer sheet 23 forms the outer shape of the outer cover 20 and is a sheet member that is continuous in the longitudinal direction from the ventral waistline portion 20A to the dorsal waistline portion 20B. The ventral outer layer sheet 21 is closer to the skin than the inner layer sheet 23 and has the same longitudinal length as the waistline joint portion 2. The dorsal outer layer sheet 22 is closer to the skin than the inner layer sheet 23 and extends toward the crotch area than the waistline joint portion 2. When the diaper 1 is in an unfolded state, the ventral outer layer sheet 21 and the dorsal outer layer sheet 22 are spaced apart in the longitudinal direction, with the inner layer sheet 23 exposed to the outside as the non-skin side of the diaper 1.

[0046] The waist elastic members 24, 25 and the buttocks elastic members 26 are elastic members that stretch in the left-right direction, and can be exemplified by thread-like elastic members. As shown in Figure 2, the waist elastic members 24, 25 overlap the waist joint 2 in the longitudinal direction. The buttocks elastic member 26 is located on the crotch side (vertically lower) of the waist joint 2 in the longitudinal direction. The waist elastic members 24, 25 and the buttocks elastic member 26 are arranged side by side in the vertical direction in the pants-like state between the inner layer sheet 23 and the ventral outer layer sheet 21 or the dorsal outer layer sheet 22, and are fixed in a stretched state in the left-right direction. Therefore, the exterior member 20 fits the waist and buttocks of the wearer.

[0047] The basic configuration of the diaper 1 has been described above, but the above-described configuration of the diaper 1 is merely an example and is not intended to be limiting. For example, a liquid-permeable intermediate sheet (e.g., a nonwoven fabric) may be disposed between the top sheet 12 and the absorbent core 11. Furthermore, for example, the ventral and dorsal exterior members may be formed of separate members, with the non-skin side of the absorbent main body 10 exposed in the crotch region, or a crotch exterior member may be provided between the ventral and dorsal exterior members, which are separate members, to connect them.

[0048] First Embodiment Next, the absorbent core 11 and the crotch elastic members 40 included in the diaper 1 of the first embodiment will be described. Figures 5 and 6 are explanatory diagrams showing the arrangement of the high-density region 11H of the absorbent core 11 and the crotch elastic members 40 in the first embodiment. Figure 7A is a cross-sectional schematic diagram of the ventral end region 11EA and the dorsal end region 11EB of the absorbent core 11, and Figure 7B is a cross-sectional schematic diagram of the crotch region 11C of the absorbent core 11. Figures 8A, 8B, 9A, and 9B are explanatory diagrams showing modified examples of the absorbent core 11. Note that the drawings only show the stretchable portions of the crotch elastic members 40.

[0049] The diaper 1 includes "crotch elastic members 40" that are located closer to the skin than the absorbent core 11 and stretchable along the longitudinal direction. The diaper 1 of this embodiment includes multiple (here, five) thread-like elastic members as the crotch elastic members 40. As shown in FIG. 4 , the multiple crotch elastic members 40 are arranged side by side at intervals in the left-right direction between the backsheet 13 and the elastic member cover sheet 17. Each crotch elastic member 40 is attached in a stretched state along the longitudinal direction. The crotch elastic members 40 may be located closer to the skin than the absorbent core 11, for example, on the skin-side surface of the backsheet 13 or between the absorbent main body 10 and the outer cover member 20. The number of thread-like crotch elastic members 40 is not particularly limited. The crotch elastic members 40 may also be a stretchable sheet (e.g., stretchable nonwoven fabric, stretchable film, etc.).

[0050] In the following description, as shown in FIG. 6 , the region defined by the stretchable portions of the crotch elastic members 40 is also referred to as the crotch elastic region E40. Specifically, when multiple thread-like crotch elastic members 40 are arranged at intervals in the left-right direction, the crotch elastic region E40 refers to the region between the leftmost crotch elastic member 40a and the rightmost crotch elastic member 40b, surrounded by an imaginary line connecting the longitudinal ventral ends of the stretchable portions of each crotch elastic member 40 arranged in the left-right direction and an imaginary line connecting the longitudinal dorsal ends of the stretchable portions of each crotch elastic member 40. When the crotch elastic member 40 is a stretchable sheet, the region where the stretchable sheet is located is referred to as the crotch elastic region. When multiple strip-like stretchable sheets or flat elastic members are arranged at intervals in the left-right direction, the same applies as in the case of thread-like elastic members. In other words, the elastic region refers to the region between the left end of the leftmost strip-like stretchable sheet or flat elastic member and the right end of the rightmost strip-like stretchable sheet or flat elastic member.

[0051] 5, when the diaper 1 in an unfolded and stretched state is viewed in the thickness direction, the absorbent core 11 is divided into three equal regions 11A, 11B, and 11C in the left-right direction, and at least some of the crotch elastic members 40 are disposed in the central region 11B of these three regions 11A, 11B, and 11C. The regions divided into three equal regions in the left-right direction are the regions 11A to 11C defined by trisecting lines Lc1 and Lc2 that divide the maximum width W0 of the absorbent core 11 into three equal parts, and it is sufficient that at least some of the crotch elastic members 40 are disposed in the central region 11B.

[0052] As described above, the crotch elastic members 40 overlap the absorbent core 11 in the thickness direction. The crotch elastic members 40 are bonded to the absorbent core 11 via the backsheet 13 with an adhesive or the like. Therefore, when the diaper 1 is worn, the crotch elastic members 40 contract in the longitudinal direction, and the absorbent core 11 is easily deformed to be pushed up toward the wearer's skin and fit closely to the wearer's crotch region. When the crotch elastic members 40 are concentrated in the lateral center of the absorbent core 11 as in this embodiment, the lateral center of the absorbent core 11 is easily deformed into a convex shape toward the upper side (the wearer's crotch region). This reduces the likelihood of a gap forming between the wearer's excretory opening (e.g., urethral opening) and the absorbent core 11, thereby preventing urine and other excretions from leaking out of the diaper 1 along the wearer's skin.

[0053] However, without being limited to the above, the crotch elastic members 40 may be disposed in each of three equal regions (11A, 11B, 11C) obtained by dividing the absorbent core 11 into three equal parts in the left-right direction. In this case, the pulling force applied when putting on the diaper 1 is easily transmitted to a wide area of ​​the absorbent core 11 in the left-right direction via the crotch elastic members 40, and the absorbent core 11 can be pulled up as a whole. Furthermore, since the absorbent core 11 is pulled up as a whole even after absorbing excrement, sagging can be suppressed.

[0054] In the diaper 1 in an unfolded and stretched state (see FIG. 5 ), at least a portion of the crotch elastic members 40 is provided in an intermediate region Rc between the lower end of the ventral waistline joint 2 (ventral waistline portion 20A) and the lower end of the dorsal waistline joint 2 (dorsal waistline portion 20B). The crotch elastic members 40 may be contained within the intermediate region Rc, or may extend to the ventral waistline portion 20A or to the dorsal waistline portion 20B. In the present embodiment, the crotch elastic members 40 are positioned toward the ventral side of the longitudinal center CL of the diaper 1. However, the present invention is not limited to this, and the crotch elastic members 40 may be positioned across the longitudinal center CL of the diaper 1 or toward the dorsal side of the diaper 1.

[0055] As shown in FIG. 7B , the absorbent core 11 of the first embodiment has a "fiber layer 111" and an "SAP sheet 112." The fiber layer 111 is formed by molding liquid-absorbent fibers into a predetermined shape (here, a roughly hourglass shape). Although a superabsorbent polymer is mixed in the liquid-absorbent fibers of the fiber layer 111 in FIG. 7B , the fiber layer 111 does not have to contain a superabsorbent polymer. The liquid-absorbent fiber is not particularly limited as long as it can be used as an absorbent core for an absorbent article, and examples of the liquid-absorbent fiber include wood pulp fiber, non-wood pulp fiber such as bagasse, kenaf, bamboo, hemp, and cotton, regenerated cellulose fiber such as rayon fiber, and semi-synthetic fiber such as acetate fiber.

[0056] The SAP sheet 112 (superabsorbent polymer sheet) is a sheet member having a first sheet portion 113, a second sheet portion 114, and a superabsorbent polymer (hereinafter also referred to as "SAP"), with the SAP sandwiched between the first sheet portion 113 and the second sheet portion 114 in the thickness direction. The SAP sheet 112 has "application regions 112p" where the SAP is arranged and "non-application regions 112n" where no SAP is arranged. The SAP sheet 112 illustrated in FIG. 6 and other figures is a rectangular sheet member that is long in the longitudinal direction of the diaper 1. Three rectangular application regions 112p (hatched regions) are arranged at intervals in the left-right direction, and the region between two adjacent application regions 112p in the left-right direction is the non-application region 112n.

[0057] As shown in FIG. 6 , the absorbent core 11 has a "crotch region 11C" located closer to the center in the longitudinal direction than the pair of waistline joints 2, a "ventral end region 11EA" overlapping the ventral waistline joint 2 in the longitudinal direction, and a "dorsal end region 11EB" overlapping the dorsal waistline joint 2 in the longitudinal direction. At least one "high-density region 11H" is arranged in the crotch region 11C of the absorbent core 11. The high-density region 11H is a region in which the average density of SAP is higher than the average density of SAP in at least one region (one-side end region) of the ventral end region 11EA and the dorsal end region 11EB. The average SAP density is the average mass (g / mm ) of SAP contained per unit volume of the absorbent core 11 before absorption. ３ )

[0058] In the absorbent core 11 of the first embodiment, as shown in Fig. 7B, the SAP sheet 112 arrangement region 112p and the fiber layer 111 are laminated in the thickness direction to form a high-density region 11H. The SAP sheet 112 shown in Fig. 6 is arranged only in the crotch region 11C. Therefore, as shown in Fig. 7A, the ventral end region 11EA and the dorsal end region 11EB are composed of only the fiber layer 111. In the fiber layer 111 of this embodiment, the basis weight (g / mm ２ ) and the basis weight of the SAP (g / mm ２ Therefore, in the high-density region 11H, the basis weight (g / mm ２ ) becomes larger. In addition, the thickness of the arrangement region 112p of the SAP sheet 112 is relatively thin, and the difference between the thickness t1 of the high-density region 11H and the thickness t2 of the ventral end region 11EA and the dorsal end region 11EB is small. Therefore, the average density (g / mm ３ ) is the average density (g / mm) of the SAP in the ventral end region 11EA ３ ) and the average density (g / mm ３ ) is higher than

[0059] In the case of the pants-type diaper 1, the crotch region 11C of the absorbent core 11 comes into close contact with the wearer's crotch when the diaper is pulled up for putting on. The crotch region 11C is located at the wearer's excretory opening (e.g., urethral opening). The high average density of the SAP in the crotch region 11C enhances the absorption capacity (water retention) of the crotch region 11C. Therefore, the excretory liquid directly received by the crotch region 11C from the wearer's excretory opening is efficiently absorbed and retained by the SAP, thereby preventing leakage of the excretory liquid. Even when a large amount of excretory liquid is excreted, the excretory liquid is dispersed in the longitudinal direction and firmly absorbed in the crotch region 11C, preventing overflow and leakage of the excretory liquid.

[0060] 5, the crotch elastic members 40 are provided in the intermediate region Rc between the lower end of the ventral waistband joint 2 and the lower end of the dorsal waistband joint 2. Therefore, when the diaper 1 is in an unfolded and stretched state, the high-density region 11H of the crotch region 11C overlaps with the crotch elastic members 40 in the longitudinal direction.

[0061] As a result, even if the SAP densely packed in the crotch region 11C absorbs excreted fluid and swells, increasing the weight of the crotch region 11C, the crotch elastic members 40 lift the crotch region 11C. This prevents the diaper 1 (the absorbent core 11) from sagging from the wearer's crotch area even after excretion. This means that the close contact between the wearer's crotch area and the absorbent core 11 is easily maintained even after excretion, preventing leakage of excreted fluid even during repeated excretion. This also reduces the discomfort and appearance of the diaper 1 due to the sagging of the absorbent core 11.

[0062] On the other hand, the ventral end region 11EA and the dorsal end region 11Eb do not directly receive excretory fluid from the wearer's excretory opening, so even if the SAP density (basis weight) is low, it is unlikely to affect leakage of excretory fluid. Therefore, by not increasing the average density of the SAP in at least one of the ventral end region 11EA and the dorsal end region 11Eb more than necessary, the graininess caused by the SAP can be reduced, thereby alleviating discomfort during wear. Furthermore, there is no need to increase the basis weight of the liquid-absorbent fiber to reduce the graininess of the SAP, and an increase in the thickness of the absorbent core due to an increase in the basis weight of the liquid-absorbent fiber is also suppressed, thereby reducing stiffness during wear. Furthermore, the manufacturing cost of the diaper 1 can be reduced. Furthermore, by lowering the average density of the SAP, problems such as reduced diffusion of excretory fluid and reduced ability to draw excretory fluid into the absorbent core 11 due to swollen SAP are less likely to occur.

[0063] 7B , only SAP is disposed between the first sheet portion 113 and the second sheet portion 114 (i.e., the mass ratio of SAP is 100%), but this is not limiting and an absorbent material other than SAP (such as a liquid-absorbent fiber) may also be included. However, it is preferable that the mass ratio of SAP in the absorbent material between the first sheet portion 113 and the second sheet portion 114 is 80% or more. This more reliably forms the high-density region 11H in the crotch region 11C, thereby increasing the absorption capacity of the high-density region 11H.

[0064] 5, when the diaper 1 is in an unfolded and stretched state, at least a portion of the high-density region 11H is preferably located closer to the ventral side than the longitudinal center CL of the diaper 1 (the center CL when the diaper 1 is divided into two equal parts in the longitudinal direction). The high-density region 11H of this embodiment is disposed across the longitudinal center CL of the diaper 1.

[0065] Compared to wearers of tape-type absorbent articles, wearers of pants-type diapers 1 (pants-type absorbent articles) spend less time lying down and more time walking and standing. Furthermore, pants-type diapers 1 are often used in conjunction with toileting, and the wearer's excretion volume may be smaller than that of tape-type absorbent articles. Therefore, if the high-density region 11H (e.g., the region 112p of the SAP sheet 112) were located only toward the back of the diaper 1 relative to the longitudinal center CL, excretory fluid absorption would be completed near the longitudinal center CL of the diaper 1, preventing the excretory fluid from spreading to the back, thereby limiting the effectiveness (function) of the high-density region 11H. Therefore, by arranging the high-density region 11H as described above, the high-density region 11H can be effectively utilized. Furthermore, the urethral opening of a wearer (especially a male) is located closer to the ventral side than directly below the crotch. Therefore, by arranging the high-density region 11H closer to the ventral side than the longitudinal center CL of the diaper 1, as in the diaper 1 of this embodiment, the high-density region 11H is more likely to directly receive excreted liquid from the urethral opening, and the excreted liquid is absorbed and retained by the SAP, thereby allowing the high-density region 11H to function appropriately and further suppress leakage of excreted liquid.

[0066] However, simply positioning the high-density region 11H closer to the ventral side than the longitudinal center CL of the diaper 1 would cause the SAP in the crotch region 11C of the diaper 1 to swell after absorbing excretory fluid, resulting in sagging of the crotch region 11C. Even if the SAP swells and expands in the dorsal region when the wearer is lying down, the wearer may not easily notice the sagging. On the other hand, a wearer of a pants-type diaper 1 who walks or otherwise engages in activities such as walking may easily notice the sagging of the crotch region, which may lead to frequent changes of the pants-type diaper. Therefore, as described above, by positioning the crotch elastic members 40 so as to overlap the high-density region 11H in the longitudinal direction of the diaper 1, sagging of the diaper 1 from the wearer's crotch region can be suppressed. In particular, the crotch elastic members 40 overlap the absorbent core 11 in the thickness direction and are aligned along the longitudinal direction of the diaper 1 without being inclined relative to the longitudinal direction of the diaper 1. Furthermore, the crotch elastic members 40 effectively pull up the absorbent core 11, further preventing sagging of the diaper 1. This reduces the frequency of changing the pants-type diaper 1, making it easier to use the diaper 1 for long periods of time and enabling more effective use of the diaper 1. However, without being limited to the above, it is sufficient that at least one high-density region 11H is disposed at any position in the crotch region 11C of the absorbent core 11.

[0067] More preferably, as shown in Figure 5, when the diaper 1 is in an unfolded and stretched state, at least a portion of the area RO where the high-density region 11H overlaps with the crotch elastic member 40 in the longitudinal direction is located closer to the ventral side than the longitudinal center CL of the diaper 1.

[0068] As described above, the wearer's urethral opening is located closer to the ventral side than directly below the crotch area. Therefore, by positioning the high-density region 11H closer to the ventral side than the longitudinal center CL of the diaper 1, the high-density region 11H is more likely to directly receive excretory fluid from the urethral opening, which is then absorbed and retained by the SAP. This further reduces leakage of excretory fluid. Furthermore, the SAP swells upon receiving excretory fluid directly from the urethral opening, and is pulled up by the crotch elastic members 40, which are located at the same longitudinal position, thereby further reducing sagging of the absorbent core 11. However, the present invention is not limited to the above. It is sufficient that at least a portion of the high-density region 11H is located closer to the ventral side than the longitudinal center CL of the diaper 1. The overlapping portion RO of the high-density region 11H and the crotch elastic members 40 in the longitudinal direction may be located only on the dorsal side of the longitudinal center CL of the diaper 1.

[0069] Furthermore, the SAP sheet 112 illustrated in FIG. 7B has a placement region 112p and a non-placement region 112n, but is not limited to this. The SAP sheet may have SAP placed over almost the entire area (for example, in areas other than the sealed outer edge). In this case, the region where the SAP sheet is placed is a high-density region. Furthermore, the SAP sheet 112 illustrated in FIG. 7B has the first sheet portion 113 and the second sheet portion 114 joined by welding or the like in the non-placement region 112n. This makes it difficult for SAP to shift in position in the SAP sheet 112. Alternatively, SAP may be fixed with an adhesive in the placement region 112p to prevent SAP from shifting.

[0070] In the absorbent core 11 illustrated in FIG. 6, the ventral end region 11EA and the dorsal end region 11EB have the same configuration, and are composed of only the fiber layer 111. Therefore, the average density (g / m ３) is higher than the average density of SAP not only in one of the ventral end region 11EA and the dorsal end region 11EB but also in the other region (the other end region). This reliably increases the absorption capacity (water retention) of the crotch region 11C, thereby suppressing leakage of excrement. Furthermore, by not increasing the average density of SAP more than necessary in both the ventral end region 11EA and the dorsal end region 11EB, the graininess of the SAP can be reduced. Furthermore, since there is no need to increase the basis weight of the liquid-absorbent fiber to reduce the graininess of the SAP, stiffness during wear can be reduced. Furthermore, this reduces the manufacturing cost of the diaper 1 and ensures the diffusion of excrement and the ability to draw excrement into the absorbent core 11.

[0071] For example, the SAP sheet 112 may extend to the ventral end region 11EA or the dorsal end region 11EB (the other-side end region), and the average density of the SAP in the high-density region 11H may be equal to or lower than the average density of the SAP in the other-side end region.

[0072] The average density of SAP in the high-density region 11H can be compared with the average density of SAP in the ventral end region 11EA or the dorsal end region 11EB in the following manner. First, the high-density region 11H (the region where SAP is densely concentrated) is identified by visual inspection or by touching the surface with the diaper 1 in an unfolded and stretched state, or with the surface of the absorbent core 11 or the surface of the core wrap sheet 18 exposed in the unfolded and stretched state. Alternatively, the high-density region 11H can be identified by visualizing the liquid-absorbent fibers and SAP using X-ray microtomography (X-ray CT) as described below. This allows the high-density region 11H to be identified when the absorbent core 11 is viewed in the thickness direction. : ScienceDirect, Carbohydrate Polymers 254, Mathias A. Hobisch et al., February 15, 2021, "How cellulose nanofibrils and cellulose microparticles impact paper strength-A visualization approach", Section "3.6.

[0073] Next, the diaper 1 (absorbent core 11) is cut in the left-right direction at any position in the longitudinal direction (a position away from the product folding position) of the target region (high-density region 11H, ventral end region 11EA, or dorsal end region 11EB). Then, using an optical microscope (e.g., Keyence Digital Microscope VHX-7000, or an equivalent), the cut surface is magnified (e.g., 30 to 100 times) and photographed. In the photographed cross-sectional image, the liquid-absorbent fibers and SAPs are identified, and the number of SAPs (pieces) in the target region and the cross-sectional area (mm ２ The cross-sectional area of ​​the target region is obtained from the length in the left-right direction and the thickness of the absorbent core 11 (preferably the average value of the thickness at multiple points in the left-right direction). Then, for each target region, the number of SAPs per unit cross-sectional area (number of SAPs / mm ２) is calculated.

[0074] Specifically, when the region surrounded by the dashed-dotted line as shown in Figure 7B is identified as the high-density region 11H, the number of SAPs per unit cross-sectional area is calculated from the number of SAPs within the dashed-dotted line and the left-right length W1 and thickness t1 of the absorbent core 11 within the dashed-dotted line. If multiple high-density regions 11H are present in the cross-sectional image (three in Figure 7B), the average number of SAPs per unit cross-sectional area of ​​each high-density region 11H is calculated. For the ventral end region 11EA or the dorsal end region 11EB, as shown in Figure 7A, the number of SAPs per unit cross-sectional area is calculated from the number of SAPs located throughout the absorbent core 11 and the left-right length W2 and thickness t2 of the entire absorbent core 11.

[0075] The above-mentioned process is performed by preparing cross-sectional images of multiple locations in the longitudinal direction of the target region. Then, for each target region, the number of SAPs per unit cross-sectional area of ​​each cross-sectional image (number / mm ２ ) is calculated. Since this average value takes into account the number of SAPs at each of a plurality of locations in the longitudinal direction (planar direction) of the absorbent core 11, the average value is the average number of SAPs per unit volume of the absorbent core 11 (number / mm ３ ) In addition, since the number of SAPs is proportional to the mass of the SAPs, the average value corresponds to the average mass of the SAPs per unit volume of the absorbent core 11, that is, the average density of the SAPs (g / mm ３ Therefore, it is confirmed that the above average value for the high-density region 11H is higher than the above average value for the ventral end region 11EA or the dorsal end region 11EB.

[0076] Not limited to the above, the number of SAPs per unit cross-sectional area (number / mm ２ ) is calculated, and then the mass of SAP per unit cross-sectional area (g / mm ２ When the absorbent core 11 contains a plurality of types of SAP, the number of SAPs for each type is calculated to obtain the total mass, and then the total mass is added up to obtain the mass of SAP per unit cross-sectional area (g / mm ２) is calculated for each target region in the same manner as in the above process. ２ ) is calculated. Since this average value takes into account the mass of SAP at each of a plurality of locations in the longitudinal direction of the absorbent core 11, the average mass of SAP per unit volume of the absorbent core 11 (g / mm ３ ) is equivalent to

[0077] Additionally, as mentioned above, X-ray microtomography (X-ray CT) can be used to visualize the liquid-absorbent fibers and SAP, allowing comparison of the SAP density in the target area.

[0078] Preferably, when the diaper 1 is in an unfolded and stretched state, the high-density region 11H (the region 112p of the SAP sheet 112) has a portion that overlaps with the crotch elastic members 40 in the thickness direction. In the absorbent core 11 shown in FIG. 6 , the central high-density region 11H of the three high-density regions 11H aligned laterally overlaps with the three crotch elastic members 40 in the thickness direction. In this case, even if the SAP in the high-density region 11H absorbs excrement and increases in weight, the high-density region 11H is directly pulled up by the crotch elastic members 40. This further reduces sagging of the diaper 1 (absorbent core 11) from the wearer's crotch region. However, the present invention is not limited to the above. The high-density region 11H and the crotch elastic members 40 do not necessarily need to overlap in the thickness direction, as in the modified example shown in FIG. 9A .

[0079] In addition, when the diaper 1 is in an unfolded and stretched state, it is preferable that a plurality of high-density regions 11H are arranged at intervals in the planar direction in the crotch region 11C of the absorbent core 11. In Fig. 6, three high-density regions 11H are arranged at intervals in the left-right direction. However, the number and arrangement pattern of the high-density regions 11H are not particularly limited, and for example, as shown in the modified example of Fig. 9B, two high-density regions 11H may be arranged side by side at an interval in the longitudinal direction.

[0080] In the high-density regions 11H, excreted liquid is absorbed and retained by the SAP, whereas between the high-density regions 11H, i.e., in the low-density regions of the SAP, excreted liquid is absorbed sequentially between the fibers of the liquid-absorbent fiber and is easily diffused. Therefore, as described above, excreted liquid can be absorbed and retained in the high-density regions 11H while being diffused between the high-density regions 11H. For example, in the case of the absorbent core 11 shown in Figure 6, between the high-density regions 11H, the fiber layer 111 and the non-disposition region 112n of the SAP sheet 112 overlap, and excreted liquid is diffused in the longitudinal direction by the fiber layer 111 extending in the longitudinal direction. This allows the absorbent core 11 to be effectively utilized in the planar direction.

[0081] In particular, when the SAP sheet 112 is disposed closer to the skin in the thickness direction than the fiber layer 111, it is preferable to arrange multiple high-density regions 11H at intervals in the planar direction. Positioning the SAP sheet arrangement region 112p (i.e., the SAP-dense portion) on the skin side allows the high-density region 11H to immediately absorb and retain excrement received. Furthermore, the SAP in the high-density region 11H also absorbs sweat and moisture from the wearer, improving the dryness of the diaper 1 and improving comfort. On the other hand, if the SAP densely packed on the skin side absorbs excrement and swells, it may hinder the excrement from being drawn into the absorbent core 11. Therefore, by dispersing multiple high-density regions 11H (the SAP-dense portion on the skin side), excrement can be drawn into the absorbent core 11 between the high-density regions 11H, even in the case of repeated excrement. This allows the absorbent core 11 to be effectively utilized in the thickness direction.

[0082] 8A and 8B , the SAP sheet 112 may be disposed closer to the skin than the fiber layer 111 in the thickness direction. In this case, the swollen SAP does not accumulate on the skin side, ensuring that excreted fluid can be drawn into the absorbent core 11 even in the event of repeated excretion. This allows the absorbent core 11 to be effectively utilized in the thickness direction.

[0083] Furthermore, when the diaper 1 is in an unfolded and stretched state, as shown in Figure 8A, the left-right length W3 of the high-density region 11H may be longer than the left-right length W4 of the crotch elastic region E40 defined by the stretchable portion of the crotch elastic member 40 (W3 > W4).

[0084] The long left-right length W3 of the high-density region 11H (the region 112p where the SAP sheet 112 is disposed) increases the absorption capacity (water retention) of the absorbent core 11 over a wide left-right area, thereby further suppressing leakage of excrement. Meanwhile, the short left-right length W4 of the crotch elastic region E40 prevents the absorbent core 11 from being pulled up over a wide left-right area, ensuring space for accommodating excrement between the wearer and the diaper 1 and suppressing overflow and leakage of excrement. Furthermore, the short left-right length W4 of the crotch elastic region E40, located in the central region 11B ( FIG. 5 ) that divides the absorbent core 11 into three equal parts left-right, appropriately reduces the width of the apex when the absorbent core 11 deforms into a convex shape toward the crotch, thereby reducing discomfort when worn.

[0085] When the SAP sheet 112 is positioned closer to the skin than the fiber layer 111 as shown in Figure 8B, the problem of reduced excrement absorption due to SAP swollen on the skin side is less likely to occur. Therefore, even if a single SAP sheet 112 (one high-density region 11H) with a long left-right length is positioned in the crotch region 11C as shown in Figure 8A, the excrement absorption into the absorbent core 11 is ensured. However, this is not limited thereto, and the left-right length of the single SAP sheet 112 (positioning region 112p) positioned closer to the skin than the fiber layer 111 may be longer than the left-right length W4 of the crotch elastic region E40.

[0086] 6, when multiple high-density regions 11H are aligned in the left-right direction, it is preferable that the left-right length W5 from the left end of the leftmost high-density region 11H to the right end of the rightmost high-density region 11H be longer than the left-right length W4 of the crotch elastic region E40 (W5>W4). In this case, too, the absorbent capacity (water retention capacity) can be increased over a wide area in the left-right direction of the absorbent core 11. However, this is not limiting, and the length W5 from the left end to the right end of the multiple high-density regions 11H may be equal to or shorter than the left-right length W4 of the crotch elastic region E40.

[0087] On the other hand, it is preferable that the left-right length W6 of one high-density region 11H is shorter than the left-right length W4 of the crotch elastic region E40 (W6<W4). This allows the multiple high-density regions 11H and the low-density SAP regions between them to be distributed in the left-right direction. Therefore, excreted fluid is absorbed and retained in the high-density regions 11H in a balanced manner in the left-right direction, while being dispersed in the low-density SAP regions. However, this is not limiting, and the left-right length W6 of one high-density region 11H may be equal to or greater than the left-right length W4 of the crotch elastic region E40.

[0088] 5, the diaper 1 has a urination region S1, which corresponds to the crotch area of ​​the wearer and contacts the wearer's urination area when the diaper 1 is in an unfolded and stretched state. The urination region S1 is a front region including the longitudinal center of the absorbent core 11. Specifically, it is a region located longitudinally centrally of the lower end of the ventral waistband joint 2 and a region longitudinally centrally of the lower end of the back-side outer sheet 22 that covers the wearer's buttocks. It is preferable that at least a portion of the region RO where the high-density region 11H overlaps with the crotch elastic member 40 in the longitudinal direction is located in the urination region S1.

[0089] This allows the high-density region 11H to easily receive excreted fluid directly from the urethral opening, and the excreted fluid is absorbed and retained by the SAP. This further reduces leakage of excreted fluid. In addition, the SAP that swells upon receiving excreted fluid directly from the urethral opening is pulled up by the crotch elastic members 40, which are positioned in the same longitudinal direction, further reducing sagging of the absorbent core 11.

[0090] As shown in Figure 5, when the diaper 1 is unfolded and stretched, the high-density region 11H is preferably located closer to the longitudinal center than the abdominal waistband joint 2. In other words, the high-density region 11H (the region 112p of the SAP sheet 112) should not extend all the way to the abdominal waistband 20A. By not extending the high-density region 11H further toward the abdominal side than necessary, the graininess of the SAP can be reduced. Furthermore, since there is no need to increase the basis weight of the liquid-absorbent fiber to reduce the graininess of the SAP, stiffness during wear can be reduced. Additionally, this can reduce the manufacturing cost of the diaper 1 and ensure the diffusibility of excrement and the ability to draw excrement into the absorbent core 11.

[0091] In the absorbent core 11 of Fig. 5, the high-density region 11H does not even reach the back waistband portion 20B. Therefore, the above-mentioned effect can be more effectively achieved. However, the high-density region 11H may reach the back waistband portion 20B. In this case, rear leakage during sleeping can be suppressed and sweat on the back can be absorbed by the SAP in the high-density region 11H.

[0092] 10A, 10B, 11A, and 11B are explanatory diagrams of an absorbent core 71 of a second embodiment. The configuration of the diaper of the second embodiment other than the absorbent core 71 is generally the same as the diaper 1 of the first embodiment, and therefore will not be described further.

[0093] The absorbent core 71 of the second embodiment also has a crotch region 71C located closer to the longitudinal center than the pair of waistline joints 2, and one-side end region (ventral end region 71EA or dorsal end region 71EB) overlapping in the longitudinal direction with the waistline joint 2 on one longitudinal side (ventral side or dorsal side). At least one high-density region 71H is arranged in the crotch region 71C of the absorbent core 71, where the average density of SAP is higher than the average density of SAP in the one-side end region.

[0094] Fig. 10A is a cross-sectional schematic diagram of the absorbent core 71 in the ventral end region 71EA or the dorsal end region 71EB (one-side end region). Figs. 10B, 11A, and 11B are cross-sectional schematic diagrams of the absorbent core 71 in the crotch region 71C. The planar shape and arrangement of the high-density region 71H of the second embodiment are the same as those of the high-density region 11H of the first embodiment (e.g., Figs. 5, 8A, 9A, and 9B), and are therefore omitted from the drawings.

[0095] The absorbent core 71 of the second embodiment has aggregates 711 of liquid-absorbent fibers, and SAP (super absorbent polymer) is mixed with the aggregates 711. The average density of the SAP mixed with the aggregates 711 in the high-density region 71H (average mass of SAP contained per unit volume of the aggregates 711: g / mm ３ ) is higher than the average density of the SAP mixed in the assembly 711 in one end region (the ventral end region 71EA or the dorsal end region 71EB). Note that the comparison of the average SAP densities in the target regions can be performed by the method described in the first embodiment.

[0096] That is, in the absorbent core 71 of the second embodiment, the high-density region 71H is formed by partially varying the distribution amount (basis weight) of the superabsorbent polymer in the liquid-absorbent fiber aggregate 711. In this case, the high-density region 71H also enhances the absorption capacity (water retention) of the crotch region 71C, thereby suppressing leakage of excrement. Although not shown, the high-density region 71H of the second embodiment also has a portion that overlaps with the crotch elastic member 40 in the longitudinal direction. Therefore, sagging of the diaper (absorbent core 71) from the crotch region of the wearer can be suppressed.

[0097] Specifically, in the ventral end region 71EA or the dorsal end region 71EB shown in Fig. 10A, a relatively small number of SAPs are dispersedly arranged in the aggregate 711. In contrast, in the crotch region 71C shown in Fig. 10B, the SAPs are densely arranged in the center in the left-right direction. This densely packed portion of the SAPs is the high-density region 71H.

[0098] In the high-density region 71H shown in Fig. 10B, SAP is densely packed throughout the entire thickness direction of the absorbent core 71, but this is not limited thereto. For example, as shown in Fig. 11A, the high-density region 71H may be formed by densely packing SAP in the skin-side portion 71s of the absorbent core 71 in the thickness direction. In this case, by arranging multiple high-density regions 71H at intervals in the left-right direction, it is possible to ensure the diffusion of excreted liquid and the ability to draw excreted liquid into the absorbent core 71. Furthermore, as shown in Fig. 11B, the high-density region 71H may be formed by densely packing SAP in the non-skin-side portion 71n of the absorbent core 71 in the thickness direction.

[0099] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0100] REFERENCE SIGNS LIST 1 pants-type disposable diaper (absorbent article), 2 waistline joint portion, 10 absorbent body, 11 absorbent core, 11H high-density region, 111 fiber layer, 112 SAP sheet (super absorbent polymer sheet), 112p placement region, 112n non-placement region, 113 first sheet portion, 114 second sheet portion, 12 top sheet, 13 back sheet, 16 side sheet, 17 elastic member cover sheet, 20 exterior member, 21 ventral outer layer sheet, 22 dorsal outer layer sheet, 23 inner layer sheet, 24 (ventral) waistline elastic member, 25 (dorsal) waistline elastic member, 26 buttocks elastic member, 31 cover sheet, 32 cover sheet, 40 crotch elastic member, 50 leakage-barrier wall portion, 51 leakage-barrier wall elastic member 52 leg elastic members, 71 absorbent core, 71H high density region, 711 aggregate,

Claims

1. A pants-type absorbent article comprising an outer member and an absorbent main body having an absorbent core, wherein the absorbent core comprises a superabsorbent polymer, and wherein a ventral waistband portion and a rear waistband portion of the outer member are joined in an annular shape by a pair of waistband joints, wherein, in an unfolded and stretched state, the article has a longitudinal direction, a left-right direction, and a thickness direction that intersect with one another, and comprises crotch elastic members that are located closer to the skin than the absorbent core and stretch along the longitudinal direction, and when viewed in the thickness direction, the absorbent core is divided into three equal parts in the left-right direction, and at least a part of the crotch elastic members is arranged in a central region of three regions, and the absorbent core has a crotch region that is located closer to the center in the longitudinal direction than the pair of waistband joints, and a one-side end region that overlaps in the longitudinal direction with the waistband joints on one side of the longitudinal direction, and the crotch region has at least one high-density region in which the average density of the superabsorbent polymer is higher than the average density of the superabsorbent polymer in the one-side end region, The pants-type absorbent article is characterized in that the high-density region has a portion that overlaps with the crotch elastic member in the longitudinal direction.

2. A pants-type absorbent article according to claim 1, characterized in that, in an unfolded and stretched state, the high-density region has a portion that overlaps with the crotch elastic member in the thickness direction.

3. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, the absorbent core has an other-side end region that overlaps in the longitudinal direction with the waistband joint on the other side in the longitudinal direction, and the average density of the superabsorbent polymer in the high-density region is higher than the average density of the superabsorbent polymer in the other-side end region.

4. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, a plurality of the high-density regions are arranged at intervals in the planar direction in the crotch region.

5. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, it has a crotch elastic region defined by the stretchable portion of the crotch elastic member, and the left-right length of the high-density region is longer than the left-right length of the crotch elastic region.

6. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, the absorbent core has a fiber layer containing liquid-absorbent fibers, a first sheet portion, and a second sheet portion, and when a sheet member in which the superabsorbent polymer is sandwiched between the first sheet portion and the second sheet portion in the thickness direction is defined as a superabsorbent polymer sheet, the superabsorbent polymer sheet has an arrangement region in which the superabsorbent polymer is arranged, and in the high-density region, the arrangement region of the superabsorbent polymer sheet and the fiber layer are laminated in the thickness direction.

7. A pants-type absorbent article according to claim 6, characterized in that, in an unfolded and stretched state, the superabsorbent polymer sheet is positioned closer to the skin in the thickness direction than the fiber layer, and a plurality of the high-density regions are arranged at intervals in the planar direction.

8. A pants-type absorbent article according to claim 6, characterized in that, in an unfolded and stretched state, the superabsorbent polymer sheet is disposed on the non-skin side in the thickness direction relative to the fiber layer.

9. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, the absorbent core has an aggregate of liquid-absorbent fibers, with the superabsorbent polymer mixed into the aggregate, and the average density of the superabsorbent polymer mixed into the aggregate in the high-density region is higher than the average density of the superabsorbent polymer mixed into the aggregate in the one-side end region.

10. A pant-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, at least a portion of the high-density region is located closer to the ventral side than the center of the pant-type absorbent article in the longitudinal direction.

11. A pants-type absorbent article according to claim 10, characterized in that, in an unfolded and stretched state, at least a part of the overlapping portion of the high-density region with the crotch elastic member in the longitudinal direction is located closer to the ventral side than the center of the pants-type absorbent article in the longitudinal direction.

12. A pants-type absorbent article as claimed in claim 1 or 2, characterized in that, in an unfolded and stretched state, it has a urination area which is an area that comes into contact with the wearer's urination area, and at least a part of the area where the high-density area overlaps with the crotch elastic member in the longitudinal direction is located in the urination area.

13. A pants-type absorbent article according to claim 1 or 2, characterized in that, in an unfolded and stretched state, the high-density region is located closer to the center in the longitudinal direction than the waistband joint on the ventral side in the longitudinal direction.

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