Underpants type absorbent article

Abstract

To provide a highly flexible underpants type absorbent article while suppressing shrinkage of an absorbent core.SOLUTION: There is provided an underpants type absorbent article (1) having absorbent cores (21-24) including liquid absorbent fibers and high absorbent polymers. In a twisting test in which a central part in a vertical direction in both end parts in a width direction of the underpants type absorbent article (1) is grasped and twisted around a virtual axis along the width direction, and a central part in the width direction in both end parts in a vertical direction of the underpants type absorbent article (1) is grasped and twisted around a virtual axis along the vertical direction, a torque value of the underpants type absorbent article (1) before absorption is equal to or less than 23.4 mN m. There is no elastic member traversing the absorbent cores (21-24) in the width direction continuously over one end to the other end in the width direction of the absorbent cores (21-24).SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a pants-type absorbent article comprising an absorbent main body including an absorbent core and an outer body located on the non-skin-contacting side of the absorbent main body. Furthermore, the absorbent core has a block structure consisting of multiple high-basis-weight sections with relatively high basis weight and low-basis-weight sections with relatively low basis weight. Furthermore, waist elastic members extending in the width direction are arranged in a stretched state in the waist portion of the outer body. The waist elastic members are arranged across the entire width of the absorbent core and overlap with the block structure of the absorbent core. It is described that, as a result, when the waist elastic members contract, the low-basis-weight sections of the absorbent core are contracted in the width direction, and the high-basis-weight sections come into close contact with each other in the width direction, making the absorbent core less likely to wrinkle and improving adhesion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-255561 Summary of the Invention [Problem to be solved by the invention]

[0004] Pants-type absorbent articles are required to be flexible (supple). Increased flexibility improves the fit to the wearer's body, reduces stiffness, and improves the ability to follow the wearer's movements. Meanwhile, in order to shrink the low-basis-weight portions of the absorbent core and narrow the gap between the high-basis-weight portions using the contractile force of the waist elastic members, as in the pant-type absorbent article of Patent Document 1, the absorbent core needs to have a certain degree of stiffness. Otherwise, the high-basis-weight portions of the absorbent core will also shrink due to the contractile force of the waist elastic members, causing the absorbent core to deform chaotically, making it more susceptible to wrinkling. Therefore, the pant-type absorbent article of Patent Document 1 suffers from the problem of insufficient flexibility due to the stiff absorbent core.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pants-type absorbent article that is highly flexible while suppressing shrinkage of the absorbent core. [Means for solving the problem]

[0006] The main invention to achieve the above object is: The vertical direction, the width direction, and the front-rear direction are perpendicular to each other, A pants-type absorbent article having an absorbent core containing liquid-absorbent fibers and a superabsorbent polymer, In a torsion test in which the pant-type absorbent article is gripped at the center portions in the up-down direction of both widthwise end portions and twisted around an imaginary axis along the widthwise direction, and the pant-type absorbent article is gripped at the center portions in the widthwise direction of both widthwise end portions and twisted around an imaginary axis along the up-down direction, the torque value of the pant-type absorbent article before absorption is 23.4 mN m or less, The pants-type absorbent article is characterized in that there is no elastic member that continuously crosses the absorbent core in the width direction from one end to the other end in the width direction of the absorbent core. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a pants-type absorbent article that is highly flexible while suppressing shrinkage of the absorbent core. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a diaper 1. [Figure 2] 1 is a schematic plan view of a diaper 1 in an unfolded and stretched state, as viewed from the skin side. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along the center line CL in FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view of an absorbent body 20 according to the present embodiment. [Figure 5] FIG. 2 is a plan view of absorbent cores 21 to 23 superimposed on one another. [Figure 6] 6A is a plan view of the skin side layer 21 and the intermediate layer 22, and FIG. 6B is a plan view of the non-skin side layer 23. As shown in FIG. [Figure 7] FIG. 2 is a schematic plan view of the absorbent body 20 as seen from the skin side. [Figure 8] 8A and 8B are explanatory diagrams of the "torsion test." [Figure 9] 1 is a schematic plan view of a diaper 1 in an unfolded and stretched state, as viewed from the non-skin side. [Figure 10] FIG. 10 is an explanatory diagram of a modified example of the diaper 1. [Figure 11] FIG. 10 is an explanatory diagram of a modified example of the diaper 1. [Figure 12] FIG. 10 is an explanatory diagram of a modified example of the diaper 1. [Figure 13] FIG. 1 is a schematic plan view of an absorbent body 10. [Figure 14] 10 is a cross-sectional view showing a modified example of the non-skin side layer 23. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings. (Aspect 1) A pants-type absorbent article having a top-to-bottom direction, a width direction, and a front-to-back direction which are perpendicular to one another, and having an absorbent core containing a liquid-absorbent fiber and a superabsorbent polymer, wherein in a torsion test in which the pant-type absorbent article is gripped at the center in the top-to-bottom direction at both end portions in the width direction and twisted around an imaginary axis along the width direction, and the pant-type absorbent article is gripped at the center in the width direction at both end portions in the top-to-bottom direction and twisted around an imaginary axis along the top-to-bottom direction, the torque value of the pant-type absorbent article before absorption is 23.4 mN·m or less, and there is no elastic member that continuously crosses the absorbent core in the width direction from one end to the other end of the absorbent core in the width direction.

[0010] According to the first aspect, the absorbent core is more easily twisted and flexible (supple) before absorption than when the torque value is greater than 23.4 mN·m. Therefore, it is more easily deformed to conform to the wearer's body and easily follows the wearer's movements. Furthermore, the absence of an elastic member spanning the entire width of the absorbent core prevents the flexible absorbent core from shrinking in the width direction due to the elastic member, which would cause wrinkles. Furthermore, the SAP constituting the absorbent core ensures the water retention capacity of excrement, while the liquid-absorbent fiber prevents excessive loss of flexibility of the pants-type absorbent article after absorbing excrement.

[0011] (Aspect 2) The pants-type absorbent article according to aspect 1, an absorbent body including the absorbent core and a transverse elastic member that stretches in the width direction, The transverse elastic members extend continuously across the region of the absorbent main body where the absorbent core is not present, from one end to the other end in the width direction of the region.

[0012] According to the second aspect, it is possible to make a part of the absorbent main body adhere closely to the body of the wearer while suppressing shrinkage of the absorbent core in the width direction by the transverse elastic members.

[0013] (Aspect 3) A pants-type absorbent article according to aspect 1 or 2, The absorbent core has transverse elastic members that stretch in the width direction, and a portion of the transverse elastic members is located at an end of the absorbent core in the width direction.

[0014] According to the third aspect, the lateral elastic members stretched during wear pull the absorbent core outward on both sides in the width direction, making it easier to maintain the flatness of the absorbent core.

[0015] (Aspect 4) A pants-type absorbent article according to aspect 1 or 2, The absorbent pack has lateral elastic members that stretch in the width direction, and the lateral elastic members are positioned outside the outer periphery of the absorbent core.

[0016] According to the fourth aspect, the contractile force of the lateral elastic members is less likely to affect the absorbent core, and shrinkage of the absorbent core in the width direction can be suppressed.

[0017] (Aspect 5) A pants-type absorbent article according to any one of aspects 1 to 4, The garment has a front waist portion, a rear waist portion, horizontal elastic members that stretch in the width direction, and an absorbent main body including the absorbent core, and in an unfolded and stretched state, the front waist portion and the rear waist portion each have a non-stretchable region where the horizontal elastic members are not located at the portion that overlaps with the absorbent main body in the thickness direction, and the widthwise length of the non-stretchable region of the front waist portion is shorter than the widthwise length of the non-stretchable region of the rear waist portion.

[0018] According to aspect 5, the fit of the front waistband is improved, making it easier for the front waistband to fit closely to the wearer's rounded abdomen. Meanwhile, the fit of the rear waistband and the absorbent main body to the wearer's buttocks is moderately controlled, ensuring space for accommodating feces.

[0019] (Aspect 6) A pants-type absorbent article according to any one of aspects 1 to 5, The garment has a front waistline portion and a rear waistline portion joined by a pair of side joints, and when at least one of the front waistline portion and the rear waistline portion is divided into four portions in the vertical direction, the contractile force of the lowest region is smaller than the contractile force of the second-lowest region.

[0020] According to the sixth aspect, by reducing the contractile force of the lowermost region, it is possible to prevent the width of the absorbent core from shrinking when receiving excrement (urine or feces), thereby ensuring an adequate absorption area and thereby preventing leakage of excrement.

[0021] (Aspect 7) A pants-type absorbent article according to any one of aspects 1 to 6, A pair of leg gathers are provided along the legs of the wearer, The leg gathers are provided with leg gather elastic members along the stretch direction thereof, and the stretch ratio of the leg gather elastic members is 2.4 times or less.

[0022] According to the seventh aspect, the contractile force of the leg gathers can be reduced compared to when the extension ratio of the leg gather elastic members is greater than 2.4 times, and shrinkage of the absorbent core can be suppressed.

[0023] (Embodiment 8) A pants-type absorbent article according to any one of embodiments 1 to 7, The garment has a pair of leg gather portions that fit around the wearer's legs and an absorbent main body including the absorbent core, the absorbent main body having a pair of leakage prevention wall portions that can stand up on the skin side on both sides in the width direction, the leg gather portions having leg gather elastic members along their stretch direction, the leakage prevention wall portions having leakage prevention wall elastic members that stretch along the up-down direction, and the contraction force of the leg gather portions being smaller than the contraction force of the leakage prevention wall portions.

[0024] According to aspect 8, it is possible to suppress shrinkage of the absorbent core due to the leg gathers. On the other hand, by increasing the contractile force of the leakage barrier walls, which are less affected by the shrinkage of the absorbent core, it is possible to suppress side leakage of body exudates from around the legs.

[0025] (Aspect 9) A pants-type absorbent article according to any one of aspects 1 to 8, The garment has a pair of leg gather sections that fit around the wearer's legs, and the leg gather sections are provided with a plurality of leg gather elastic members along their stretch direction, with the contractile force of the leg gather elastic member provided on the innermost side being greater than the contractile force of the leg gather elastic member provided on the outermost side.

[0026] According to the ninth aspect, the contractile force of the innermost leg gather elastic members allows the pants-type absorbent article to fit tightly around the legs of the wearer, thereby preventing side leakage of body exudates. By reducing the contractile force of the outermost leg gather elastic members, shrinkage of the absorbent core can be prevented.

[0027] (Aspect 10) A pants-type absorbent article according to any one of aspects 1 to 8, The garment has a pair of leg gather sections that fit around the wearer's legs, and the leg gather sections are provided with a plurality of leg gather elastic members along their stretch direction, with the contraction force of the leg gather elastic member provided on the innermost side being smaller than the contraction force of the leg gather elastic member provided on the outermost side.

[0028] According to the tenth aspect, the contractile force of the leg gather elastic members closest to the absorbent core is suppressed, so that shrinkage of the absorbent core can be further suppressed.

[0029] (Aspect 11) A pants-type absorbent article according to any one of aspects 1 to 10, The absorbent body has an absorbent main body including the absorbent core, and the absorbent main body has a pair of leg gather portions on both sides in the width direction, and the leg gather portions are provided with leg gather elastic members that stretch along the up-down direction, and when in an unfolded and stretched state, the leg gather elastic members are not provided in the innermost region when the region from the end of the absorbent core to the end of the absorbent main body in the width direction is divided into three.

[0030] According to the eleventh aspect, the contractile force of the leg gather elastic members is less likely to affect the absorbent core, and vertical shrinkage of the absorbent core can be further suppressed.

[0031] (Aspect 12) A pants-type absorbent article according to any one of aspects 1 to 11, the leg gather elastic member is provided on one side of the inner leg gather elastic member in the width direction; the leg gather elastic member is provided with three or more leg gather elastic members that stretch along the up-down direction; and in a deployed and stretched state, the leg gather elastic member has a longitudinal direction perpendicular to the width direction; in the width direction, the region between the innermost leg gather elastic member and the outermost leg gather elastic member is defined as a leg gather elastic region; when the leg gather elastic region is divided into two equal parts in the width direction, the region located on the inner side is defined as an inner leg gather elastic region; and the region located on the outer side is defined as an outer leg gather elastic region; the average value of the length of the portion of the leg gather elastic member located in the inner leg gather elastic region where a stretchable force is applied in the longitudinal direction is shorter by 10% or more than the average value of the length of the portion of the leg gather elastic member located in the outer leg gather elastic region where a stretchable force is applied in the longitudinal direction.

[0032] According to aspect 12, shrinkage of the absorbent core in the vertical direction can be suppressed compared to when the average length of the leg gather elastic members arranged in the inner leg gather elastic region is longer than 90% of the average length of the leg gather elastic members arranged in the outer leg gather elastic region.

[0033] (Aspect 13) A pants-type absorbent article according to any one of aspects 1 to 12, The absorbent core has a skin-side core wrap sheet portion that covers at least a portion of the skin-side side of the absorbent core, a non-skin-side core wrap sheet portion that covers at least a portion of the non-skin-side side of the absorbent core, a top sheet that is located closer to the skin than the skin-side core wrap sheet portion, and a back sheet that is located closer to the skin than the non-skin-side core wrap sheet portion, and has a portion where the top sheet and the back sheet are adhered.

[0034] According to the thirteenth aspect, since the topsheet is not folded back, the rigidity around the absorbent core can be reduced, and the torque value of the pants-type absorbent article can be reduced. Furthermore, since the topsheet is not folded back, the thickness around the absorbent core can be reduced, and the pants-type absorbent article has a neater appearance similar to that of underwear.

[0035] (Aspect 14) A pants-type absorbent article according to any one of aspects 1 to 13, The absorbent garment has a front waistband, a rear waistband, horizontal elastic members that stretch in the width direction, and an absorbent main body including the absorbent core, wherein the absorbent core has a low basis weight region having a basis weight lower than that of the surrounding area, and in an unfolded and stretched state, the front waistband and the rear waistband each have a non-stretchable region where the horizontal elastic members are not located at a portion that overlaps with the absorbent main body in the thickness direction, and at least one of the non-stretchable regions of the front waistband and the rear waistband overlaps with the low basis weight region in the width direction and extends outward in the width direction beyond the low basis weight region.

[0036] According to the fourteenth aspect, the contractile force of the lateral elastic members is less likely to be exerted on the parts of the absorbent core that are easily deformed due to the low basis weight region, thereby suppressing shrinkage of the absorbent core in the width direction.

[0037] (Aspect 15) A pants-type absorbent article according to any one of aspects 1 to 14, In the crotch portion, which is located between the legs of a wearer when worn, the absorbent core has a constricted portion constricted on the inner side in the width direction.

[0038] According to the fifteenth aspect, the flexibility of the absorbent core is increased, and the torque value of the pants-type absorbent article before absorption can be reduced.

[0039] (Aspect 16) A pants-type absorbent article according to aspect 15, The garment has an absorbent main body including the absorbent core, and in an unfolded and stretched state, the front waistband and the rear waistband each have a non-stretchable region where the lateral elastic member is not located at a portion where the non-stretchable region overlaps with the absorbent main body in the thickness direction, and the outer widthwise end of at least one of the non-stretchable regions of the front waistband and the rear waistband is located outside the narrowest point of the waistband in the width direction or coincides with the widthwise position of the narrowest point.

[0040] According to the sixteenth aspect, the contractile force of the lateral elastic members is less likely to reach the constricted portions of the absorbent core, and therefore the deformation of the absorbent core sandwiched between the wearer's legs along the constricted portions is less likely to be hindered by the lateral elastic members.

[0041] (Aspect 17) The pants-type absorbent article according to aspect 15, The device has an absorbent main body including the absorbent core, and in an unfolded and stretched state, the front waistband and the rear waistband each have a non-stretchable region where the lateral elastic member is not located at a portion where the non-stretchable region overlaps with the absorbent main body in the thickness direction, and the outer end of the widthwise direction of at least one of the non-stretchable regions of the front waistband and the rear waistband is located widthwise inside the narrowest point of the constricted portion.

[0042] According to the seventeenth aspect, when the wearer's legs exert a strong clamping force, the lateral elastic members can pull the constricted portions outward in the width direction, thereby preventing the absorbent core from being distorted uncontrollably by the legs.

[0043] (Aspect 18) A pants-type absorbent article according to any one of aspects 1 to 17, The absorbent core has a plurality of compressed portions formed to partially compress the absorbent core in the thickness direction thereof.

[0044] According to the eighteenth aspect, the rigidity of the absorbent core is increased appropriately, and shrinkage of the absorbent core can be suppressed.

[0045] (Aspect 19) A pants-type absorbent article according to any one of aspects 1 to 18, The absorbent core has a plurality of absorbent layers, each of which has an SAP layer formed solely from the superabsorbent polymer, the SAP layer being laminated on a base sheet and having a longitudinal direction perpendicular to the width direction in an unfolded and stretched state, the SAP layer sheet in which the SAP layer is laminated on the base sheet having a high basis weight region with a basis weight higher than that of the surrounding area, the high basis weight region being arranged so that points of maximum thickness are located intermittently in the longitudinal direction and the width direction, the maximum thickness being within 3 mm, and the distance between adjacent points of maximum thickness being 5 times or less the maximum thickness.

[0046] According to the 19th aspect, the low-basis weight regions surrounding the high-basis weight regions act as folding points, making the absorbent core (SAP layer sheet) more easily deformable and increasing its flexibility. This allows for a lower torque value of the pants-type absorbent article before absorption. Furthermore, the absorbent core can be thinner than when the maximum thickness is greater than 3 mm. Furthermore, since multiple high-basis weight regions are arranged at closer intervals than when the distance between the maximum thickness points is greater than five times the maximum thickness, the flexibility of the absorbent core is further increased.

[0047] (Aspect 20) A pants-type absorbent article according to any one of aspects 1 to 19, The absorbent core has a plurality of absorbent layers stacked in its thickness direction, the plurality of absorbent layers having a first absorbent layer and a second absorbent layer, and in an unfolded and extended state has a longitudinal direction perpendicular to the width direction, and in the longitudinal direction, the rear end of the first absorbent layer is located more centrally than the rear end of the second absorbent layer.

[0048] According to Aspect 20, the number of layers in the rear absorbent core is reduced, thereby reducing rigidity. This prevents the absorbent core from feeling stiff when the user is lying on their back. The large number of layers in the front absorbent core allows for more efficient absorption and retention of excreted urine, preventing leakage.

[0049] (Aspect 21) The pants-type absorbent article according to aspect 20, It has a transverse elastic member that stretches in the width direction, and in an unfolded and stretched state, at the rear end of the absorbent core in the longitudinal direction, in a region where the first absorbent layer is not present, a portion of the transverse elastic member is located at the end of the absorbent core in the width direction.

[0050] According to the twenty-first aspect, the portions of the absorbent core that are thinner due to the absence of the first absorbent layer can be efficiently pulled outward in the width direction by the transverse elastic member, thereby ensuring the flatness of the second absorbent layer.

[0051] (Aspect 22) A pants-type absorbent article according to any one of aspects 1 to 21, The absorbent core has a skin-side layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the liquid-absorbent fiber, an intermediate layer in which the volume occupied by the liquid-absorbent fiber is larger than the volume occupied by the superabsorbent polymer, and a non-skin-side layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the liquid-absorbent fiber, and the intermediate layer is located on the non-skin side in the thickness direction of the skin-side layer, and the non-skin-side layer is located on the non-skin side in the thickness direction of the intermediate layer.

[0052] According to the 22nd aspect, the liquid-absorbent fiber in the middle layer quickly draws excreted liquid into the absorbent core. The excreted liquid then migrates to the non-skin-side layer, where it is firmly retained by the superabsorbent polymer. Furthermore, the superabsorbent polymer in the skin-side layer prevents excreted liquid from flowing back.

[0053] (Aspect 23) A pants-type absorbent article according to any one of aspects 1 to 22, The absorbent core has multiple absorbent layers stacked in its thickness direction, and one or more of the absorbent layers located closer to the skin than the absorbent layer located closest to the skin in the thickness direction do not contain nonwoven fabric.

[0054] According to the twenty-third aspect, the number of absorbent layers can be reduced and the thickness of the absorbent layers can be reduced while ensuring the absorption performance of the absorbent layers that do not contain nonwoven fabric, thereby reducing the torque value of the pants-type absorbent article before absorption.

[0055] (Aspect 24) The pants-type absorbent article according to aspect 23, The absorbent layer located closest to the skin in the thickness direction does not contain water-absorbent resin powder.

[0056] According to the twenty-fourth aspect, it is possible to prevent the absorbent layer closest to the skin from being excessively swollen by the water-absorbent resin powder, which would hinder the absorption of excrement. Therefore, it is possible to reduce the number of absorbent layers stacked and the thickness of the absorbent layer while maintaining the absorbent performance. Therefore, it is possible to reduce the torque value of the pants-type absorbent article before absorption.

[0057] (Aspect 25) The pants-type absorbent article according to aspect 23, The superabsorbent polymer contained in the absorbent layer located closest to the skin in the thickness direction has a liquid permeation rate under load of more than 10 seconds.

[0058] According to the 25th aspect, compared to when the liquid permeation rate under load is 10 seconds or less, localized absorption of excreted liquid can be suppressed, and the absorbent core can be effectively utilized in the planar direction. Therefore, the number of stacked absorbent layers and the thickness of the absorbent layers can be reduced while maintaining the absorption performance. Therefore, the torque value of the pants-type absorbent article before absorption can be reduced.

[0059] === Implementation form === As an example of a pants-type absorbent article according to the present invention, a pants-type disposable diaper 1 for infants (hereinafter also referred to as "diaper 1") will be described. However, pants-type absorbent articles according to the present invention also include shorts-type napkins and the like. Furthermore, the wearer of a pants-type absorbent article is not limited to infants, but may also be an adult or a living organism such as an animal.

[0060] <<<Composition of Diaper 1>>> FIG. 1 is a schematic perspective view of a 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 the center line CL in FIG. 2. The "stretched state" of the diaper 1 refers to a state in which the entire diaper 1 is stretched without wrinkles, specifically, a state in which the dimensions of each component constituting the diaper 1 (e.g., the absorbent main body 10 and waist-lined sections 30 and 40, which will be described later) are stretched to the same dimensions as or close to the dimensions of each component alone. The "unfolded state" of the diaper 1 refers to a state in which the diaper 1 is opened and unfolded in a flat plane by separating a pair of side joining sections 2 provided on both sides of the diaper 1.

[0061] The diaper 1 has a vertical direction, a width direction, and a front-to-rear direction that are perpendicular to one another, and has a waist opening BH and a pair of leg openings LH. The upper side in the vertical direction corresponds to the waist opening BH side, and the lower side corresponds to the crotch side. The front side in the front-to-rear direction corresponds to the wearer's abdomen side, and the rear side corresponds to the wearer's back side. The width direction is a direction along the stretch direction of the elastic threads 33, 43 of the front waist portion 30 and the rear waist portion 40. The vertical direction is a direction perpendicular to the stretch direction.

[0062] The diaper 1 is a so-called three-piece pants-type diaper having an absorbent main body 10 including an absorber 20 (absorbent cores 21-23) and a pair of waist-surrounding sections 30, 40. Of the pair of waist-surrounding sections, the one covering the wearer's abdominal side is also referred to as the front waist-surrounding section 30, and the one covering the wearer's dorsal side is also referred to as the rear waist-surrounding section 40.

[0063] In the unfolded state shown in Fig. 2, the diaper 1 has a longitudinal direction, a width direction, and a thickness direction, which are perpendicular to one another. The longitudinal direction is along the longitudinal direction of the absorbent main body 10 and along the vertical direction of the pants-type diaper 1. The thickness direction is the direction in which the materials constituting the diaper 1 are layered, as shown in Fig. 3. In the thickness direction, the side that contacts the wearer's skin is referred to as the skin side, and the opposite side is referred to as the non-skin side. In the unfolded state, the front waistband 30 and the rear waistband 40 are aligned parallel to each other with a gap in the longitudinal direction, with the absorbent main body 10 spanning between them, with each longitudinal end of the absorbent main body 10 joined and fixed to the skin side of the nearest waistband 30, 40, resulting in a generally H-shaped external shape in a plan view. From this state, the absorbent main body 10 is folded in half along the longitudinal center line CL. In this folded state, the opposing front waistline portion 30 and rear waistline portion 40 are joined and connected at both widthwise sides by a pair of side joining portions 2. The side joining portions 2 are formed by known joining means such as welding or adhesive.

[0064] The absorbent main body 10 comprises an absorbent body 20 (described in detail below), a liquid-permeable top sheet 12 arranged closer to the skin than the absorbent body 20, a liquid-impermeable back sheet 13 arranged closer to the skin than the absorbent body 20, an exterior sheet 14 arranged closer to the skin than the back sheet 13, and a pair of side sheets 15 arranged on both sides in the width direction of the skin-side surface of the top sheet 12. However, the absorbent main body 10 may also comprise sheet members other than those mentioned above. For example, a second sheet (not shown) may be provided between the top sheet 12 and the absorbent body 20 in the thickness direction.

[0065] The absorbent main body 10 is provided with a pair of leakage preventing walls 3 on both sides in the width direction along the longitudinal direction of the absorbent main body 10. In Fig. 3, a leakage preventing wall elastic member 16 such as rubber thread is attached between the side sheets 15 folded in half in a stretched state along the longitudinal direction of the absorbent main body 10. This allows the leakage preventing walls 3 to stand up against the skin. However, this is not limited to the above, and the pair of leakage preventing walls may be formed by folding a part of the outer sheet 14 against the skin at multiple points while extending outward beyond both ends of the absorber 20, or the diaper 1 may not have the leakage preventing walls 3.

[0066] The absorbent main body 10 also has a pair of leg gather portions LG on both sides in the width direction. The leg gather portions LG are provided with a plurality of leg gather elastic members 17 such as rubber threads that stretch along the longitudinal direction (vertical direction). In Fig. 3, the end of the exterior sheet 14 extending outward in the width direction from the absorbent main body 20 is folded back onto the back sheet 13. Between the folded back portions of the exterior sheet 14, the leg gather elastic members are attached in a stretched state along the longitudinal direction.

[0067] The front waistline portion 30 and the rear waistline portion 40 have the same planar shape in the unfolded and stretched state, a rectangular shape elongated in the width direction. In this specification, the portions of the outer covering overlapping the side joint portion 2 in the longitudinal direction (vertical direction) are referred to as the front waistline portion 30 and the rear waistline portion 40. The front waistline portion 30 and the rear waistline portion 40 each have skin-side sheets 31, 41, non-skin-side sheets 32, 42, and multiple waistline elastic members 33, 43 such as rubber threads. The multiple waistline elastic members 33, 43 are arranged vertically between the skin-side sheets 31, 41 and the non-skin-side sheets 32, 42 and are attached in a stretched state in the width direction. The stretchability of the waistline elastic members 33, 43 allows the front waistline portion 30 and the rear waistline portion 40 to fit the waist of the wearer. Furthermore, cover sheets 34, 44 may be provided so as to cover the upper end of the absorbent main body 10 from the skin side. The cover sheets 34, 44 can prevent the absorbent main body 10 from opening open or the like.

[0068] The basic configuration of the diaper 1 has been described above, but the above configuration is merely an example and is not intended to be limiting. For example, the front waistline portion 30 and the rear waistline portion 40 may be formed from a single continuous member, or an outer member may be provided in the crotch area connecting the front waistline portion 30 and the rear waistline portion 40. Furthermore, the elastic members such as the waistline elastic members 33, 43 may be sheet-like elastic members instead of rubber threads.

[0069] <<<Configuration of absorbent body 20>>> Fig. 4 is a cross-sectional schematic diagram of the absorbent body 20 of this embodiment. Fig. 5 is a plan view of the absorbent cores 21 to 23 superimposed on each other. Fig. 6A is a plan view of the skin side layer 21 and the intermediate layer 22, and Fig. 6B is a plan view of the non-skin side layer 23. Fig. 7 is a schematic plan view of the absorbent body 20 as seen from the skin side.

[0070] As shown in FIG. 4, the absorbent body 20 has absorbent cores 21-23 between a core wrap sheet 25 on the skin side and a core wrap sheet 26 on the non-skin side. The absorbent cores 21-23 are components that absorb and retain excretory fluids such as urine, and include a liquid-absorbent fiber 201 and a super absorbent polymer. The liquid-absorbent fiber 201 and the super absorbent polymer (hereinafter also referred to as SAP) are not particularly limited as long as they can be used as the absorbent core of an absorbent article. For example, the liquid-absorbent fiber 201 can be wood pulp fiber, non-wood pulp fiber such as bagasse, kenaf, bamboo, hemp, or cotton, regenerated cellulose fiber such as rayon fiber, or semi-synthetic fiber such as acetate fiber. Examples of SAP include starch-based, cellulose-based, and synthetic polymer-based polymer absorbents. The core wrap sheets 25 and 26 are liquid-permeable sheet materials, such as tissue and nonwoven fabric. When the core wrap sheets 25, 26 are nonwoven fabrics (hydrophilic SMS (spunbond, meltblown, spunbond) nonwoven fabrics, spunlace nonwoven fabrics, etc.), they are stronger and more tear-resistant than tissues and the like, making them suitable as base sheets for forming the absorbent body 20. In particular, SMS nonwoven fabrics are thinner than other nonwoven fabrics, and therefore can improve the flexibility of the absorbent body 20.

[0071] The absorbent cores 21-23 each include a skin-side layer 21, an intermediate layer 22, and a non-skin-side layer 23. The intermediate layer 22 is located closer to the skin than the skin-side layer 21 in the thickness direction, and the non-skin-side layer 23 is located closer to the skin than the intermediate layer 22 in the thickness direction. The skin-side layer 21 has a first thickness t1, and is a layer in which the volume occupied by SAPs is larger than the volume occupied by the liquid-absorbent fibers 201. The intermediate layer 22 has a second thickness t2, and is a layer in which the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by the SAPs. The non-skin-side layer 23 has a third thickness t3, and is a layer in which the volume occupied by SAPs is larger than the volume occupied by the liquid-absorbent fibers 201.

[0072] As a result, the liquid-absorbent fibers of the intermediate layer 22 can quickly draw excreted liquid into the absorbent body 20. The excreted liquid that then migrates to the non-skin side layer 23 can be firmly held by the SAP. Furthermore, even if the excreted liquid that has been drawn into the absorbent body 20 attempts to return to the skin side of the absorbent body 20, the SAP of the skin side layer 21 can prevent it from returning onto the top sheet 12 (so-called rewetting). This makes it easier to maintain the dryness of the surface of the top sheet 12.

[0073] Furthermore, the absorbent body 20 of this embodiment further includes a skin-side upper layer 24, which is located closer to the skin in the thickness direction than the skin-side layer 21 and has a fourth thickness t4 that is thinner than the first thickness t1 of the skin-side layer 21. The skin-side upper layer 24 is a layer in which the volume occupied by the liquid-absorbent fiber 201 is greater than the volume occupied by the SAP. Specifically, the skin-side upper layer 24 of this embodiment is composed only of the liquid-absorbent fiber 201. The presence of the skin-side upper layer 24, in which the volume proportion of the liquid-absorbent fiber is high, further reduces the wearer's perception of the unevenness of the superabsorbent polymer. Furthermore, the liquid-absorbent fiber of the skin-side upper layer 24 makes it difficult for the superabsorbent polymer in the skin-side layer to roll around within the layer, preventing a deterioration in the tactile feel.

[0074] The skin-side upper layer 24 is laminated so as to cover at least the shape of the skin-side layer 21 shown in Fig. 5. The skin-side layer 21 has a constricted portion 212 in the longitudinal center, and the skin-side upper layer 24 may also be laminated in the constricted portion 212 in a portion outer than both ends of the constricted portion 212 in the width direction. The skin-side layer 21 has a low-basis weight region 211 in which the basis weight of the absorbent core is lower than that of the surrounding area, and the skin-side upper layer 24 may be disposed so as to overlap the low-basis weight region 211 of the skin-side layer 21 in a plan view. There is a risk that SAPs from the periphery of the low-basis weight region 211 may shift and intrude into the low-basis weight region 211. However, the presence of the skin-side upper layer 24 covering the low-basis weight region 211 from the skin side makes it less likely that SAPs included in regions outer than the low-basis weight region 211 in the width direction and length direction will shift, and the shape of the low-basis weight region 211 can be more easily maintained. However, the absorbent core may not have the skin-side upper layer portion 24.

[0075] 4, in this embodiment, the skin side layer 21 and the intermediate layer 22 are integrally formed, and therefore the volume occupancy of SAP decreases and the volume occupancy of liquid-absorbent fiber 201 increases from the skin side layer 21 toward the intermediate layer 22. Such an absorbent core can be manufactured, for example, by adjusting the order, amount, timing, etc. of feeding the SAP and liquid-absorbent fiber 201 into a forming mold (recess) that corresponds to the shape of the absorbent core and is provided on the outer circumferential surface of a rotating drum.

[0076] In this embodiment, the skin side layer 21 and the intermediate layer 22 are laminated integrally, i.e., adjacent to each other in the thickness direction, without any adhesive or nonwoven fabric in between. This prevents the adhesive or nonwoven fabric from interfering with the transfer of excreted fluid from the skin side layer 21 to the intermediate layer 22, and increases the rate of absorption by the intermediate layer 22.

[0077] Furthermore, in this embodiment, the non-skin side layer 23 is not formed integrally with the intermediate layer 22, but is laminated adjacent to the intermediate layer 22 in the thickness direction via the non-woven fabric 27. The presence of the non-woven fabric 27 allows the excreted liquid to diffuse in the planar direction on the non-woven fabric 27 before migrating from the intermediate layer 22 to the non-skin side layer 23. Therefore, the excreted liquid diffused in the planar direction can be migrated to the non-skin side layer 23, allowing the absorbent cores 21-23 to be effectively utilized in the planar direction. Note that the non-woven fabric 27 is a core wrap sheet that covers the surfaces of the intermediate layer 22 and the non-skin side layer 23, and is not included in the absorbent layers that make up the absorbent core.

[0078] Furthermore, the comparison of the volumes occupied by the liquid absorbent fiber 201 and SAP in each of the skin side layer 21, the intermediate layer 22, the non-skin side layer 23, and the skin side upper layer 24 can be confirmed by the following method. For example, with the diaper 1 in a natural, dry state without any external force acting on it, the diaper 1 (absorbent body 20) is cut widthwise at any position in the longitudinal direction of the absorbent body 20, specifically at a position where the four layers 21 to 24 are stacked and away from the product folding position. Next, the cut surface is magnified (e.g., 30 to 100 times) and photographed using an optical microscope (e.g., Keyence Digital Microscope VHX-7000 or equivalent). In the photographed cross-sectional image, the liquid-absorbent fibers 201 and SAP are identified. Then, in the cross-sectional image, it is confirmed that the following are layered in order from the skin side in the thickness direction: a skin-side upper layer 24 in which the area occupied by the liquid-absorbent fibers 201 is larger than that of the SAP; a skin-side layer 21 in which the area occupied by the SAP is larger than that of the liquid-absorbent fibers 201; an intermediate layer 22 in which the area occupied by the liquid-absorbent fibers 201 is larger than that of the SAP; and a non-skin-side layer 23 in which the area occupied by the SAP is larger than that of the liquid-absorbent fibers 201. If the above is confirmed, the four layers 21 to 24 of this embodiment are identified. Cross-sectional images are prepared at multiple locations (e.g., 10 locations) along the longitudinal direction of the absorbent body 20 in which such four layers 21 to 24 can be confirmed, and if the area occupied by the SAP is larger than the area occupied by the liquid-absorbent fibers 201 in all of the cross-sectional images, then that layer is a layer in which "the volume occupied by the SAP is larger than the volume occupied by the liquid-absorbent fibers," and if the area occupied by the liquid-absorbent fibers 201 is larger than the area occupied by the SAP in all of the cross-sectional images, then that layer is a layer in which "the volume occupied by the liquid-absorbent fibers is larger than the volume occupied by the SAP."

[0079] In addition, a comparison of the volumes occupied by the liquid-absorbent fibers 201 and SAP in each layer can be made by visualizing the liquid-absorbent fibers 201 and SAP using X-ray microtomography (X-ray CT), for example, by the method described below: Science Direct, 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. X-ray microtomography", https: / / www.sciencedirect.com / science / article / pii / S0144861720315794.

[0080] <<<Flexibility of the diaper 1 and suppression of shrinkage of the absorbent body 20>>> Figures 8A and 8B are explanatory diagrams of the "torsion test." Figure 8A shows a measurement method in which the diaper 1 is twisted around a virtual axis Va1 along the width direction of the diaper 1. Figure 8B shows a measurement method in which the diaper 1 is twisted around a virtual axis Va2 along the up-down direction of the diaper 1. Figure 9 is a schematic plan view of the diaper 1 in an unfolded and stretched state, viewed from the non-skin side.

[0081] Pants-type absorbent articles are required to be flexible (supple). In a "torsion test," the diaper 1 of this embodiment has a torque value of 23.4 mN·m or less before absorption. The torsion test involves gripping the vertical center portions of both widthwise ends of the pants-type absorbent article (diaper 1) and twisting it around an imaginary axis Va1 along the widthwise direction (FIG. 8A), and gripping the vertical center portions of both widthwise ends of the pants-type absorbent article (diaper 1) and twisting it around an imaginary axis Va2 along the vertical direction (details will be described later).

[0082] The diaper 1 is more easily twisted and flexible (supple) before absorption than pants-type absorbent articles with a torque value of more than 23.4 mN·m before absorption. This allows the diaper 1 to easily conform to the wearer's body and easily follow the wearer's movements. This provides a good fit, reduces gaps between the diaper 1 and the wearer, and prevents leakage of excrement. Furthermore, the diaper 1 is less stiff, improving comfort.

[0083] Pants-type absorbent articles (diapers 1) of the present embodiment, including the absorber 20 configured as shown in FIGS. 4 to 7, were fabricated and subjected to a torsion test. The torque values of the S-size diapers 1 of the present embodiment before absorption were 16.3 mN·m, the XL-size diapers 1 before absorption were 21.1 mN·m, and the XXL-size diapers 1 before absorption were 23.4 mN·m. As a comparative example, a commercially available pants-type diaper for infants (L-size, with a two-layer absorbent core, the upper layer of which is composed of liquid-absorbent fibers 201 and SAP and has a substantially T-shaped planar shape, and the lower layer is a rectangular SAP sheet) was also subjected to a torsion test. The torque value of the comparative diaper before absorption was 29.3 mN·m. These results demonstrate that the diaper 1 of the present embodiment has a lower torque value and higher flexibility than the commercially available comparative diapers. Furthermore, the torque values of the XL and XXL sizes of the diaper 1 of the present embodiment, which are larger than the L size of the comparative example, are also lower than the torque values of the comparative example, which also demonstrates that the flexibility of the diaper 1 of the present embodiment is high.

[0084] Furthermore, SAP swells after absorbing excrement. Therefore, an absorbent core composed only of SAP becomes denser and harder after absorbing excrement, which tends to reduce the flexibility of the diaper 1. In contrast, the absorbent cores 21-24 of this embodiment contain not only SAP but also liquid-absorbent fibers 201. The liquid-absorbent fibers 201 tend to maintain gaps between the fibers even after absorbing excrement. Therefore, with the absorbent cores 21-24 of this embodiment, SAP ensures the water retention capacity of excrement, while the liquid-absorbent fibers 201 prevent an excessive decrease in the flexibility of the diaper 1 after absorbing excrement (a significant increase in torque value). Preferably, the mass of SAP relative to the total mass of the absorbent cores 21-24 is 80% or less. This makes it easier to maintain the flexibility of the diaper 1 after absorption, compared to when the mass ratio of SAP is greater than 80%.

[0085] In particular, in the absorbent body 20 of this embodiment, the SAPs in the skin-side layer 21 and the non-skin-side layer 23 occupy a large volume, which makes it possible to efficiently suppress rewet and increase the water retention capacity (absorption performance). Furthermore, the liquid-absorbent fibers 201 occupy a large volume in the intermediate layer 22, which maintains the flexibility (low torque value) of the absorbent body 20. By efficiently increasing the water retention capacity, it is possible to reduce the basis weight and thickness of the absorbent core, which also makes it possible to reduce the torque value of the diaper 1 before absorption. Specifically, the average basis weight of the non-skin-side layer 23 is higher than that of the skin-side layer 21. A suitable average basis weight of the non-skin-side layer 23 is 50 g / m 2 ~350g / m 2 Specifically, when the diaper 1 is a size S, the average basis weight of the non-skinside layer 23 is 173 g / m 2 The average basis weight of the skin side layer 21 is preferably about 82 g / m 2 When the diaper 1 is an XXL size, the average basis weight of the non-skin side layer 23 is about 300 g / m 2 The average basis weight of the skin side layer 21 is preferably about 171 g / m 2 The skin-side layer 21, which has a low average basis weight, is less likely to swell after retaining water, and therefore the skin-side layer 21 is less likely to experience absorption inhibition due to swelling of the SAP. The feel of the skin-side layer (gritty feeling of the SAP) is also less likely to deteriorate. The thickness of each layer will be described later.

[0086] Furthermore, as shown in FIG. 9, the diaper 1 does not have any elastic members that continuously traverse the absorbent cores 21-24 in the width direction from one end to the other end of the absorbent cores 21-24 in the width direction.

[0087] For example, Fig. 9 shows only the portions of the elastic members of the diaper 1 that are stretched (so-called effective length portions). Similarly, other drawings show only the effective length portions of each elastic member. As shown in Fig. 9, among the front and rear waist elastic members 33, 43, the waist elastic members 33a, 43a that overlap the absorbent cores 21-24 in the longitudinal direction are cut at a portion that overlaps with the absorbent cores 21-24 in the thickness direction, and are not stretched. Thus, in the diaper 1 of this embodiment, the effective length portions of the waist elastic members 33, 43 do not extend continuously from one end to the other in the width direction of the absorbent cores 21-24 across the absorbent cores 21-24 in the width direction.

[0088] As mentioned above, the low torque value of the diaper 1 means that the absorbent cores 21-24, which are the main constituent materials of the diaper 1, are also flexible. Therefore, the absence of elastic members spanning the entire width of the absorbent cores 21-24 reduces the contractile force of the elastic members acting on the flexible absorbent cores 21-24, preventing the absorbent cores 21-24 from shrinking in the width direction and causing wrinkles. Maintaining the flatness of the absorbent cores 21-24 ensures the absorption area of the absorbent cores 21-24. Furthermore, gaps are less likely to form between the absorbent cores 21-24 and the wearer, thereby reducing the risk of leakage of excrement. Furthermore, ensuring the width of the absorbent cores 21-24 reduces user (parent, etc.) concerns about tightness and leakage. Furthermore, the absorbent cores 21-24 are prevented from deforming and protruding outside the diaper 1, giving the diaper 1 a streamlined appearance similar to underwear.

[0089] (torsion test) In the torsion test, the torque value of the diaper 1 can be measured using an Imada torque tester (model number: EX-0762) or an equivalent device. The test environment is a room temperature of 20±2°C and a humidity of 60±5%.

[0090] (1) First, prepare the diaper 1 to be measured (the diaper 1 immediately after being removed from the package and before absorption), and identify the position to be clamped by the chuck 60 of the torque tester. As shown in the left diagrams of Figures 8A and 8B, the maximum width of the absorbent body 20 is divided into two equal parts in the width direction, and a line C1 extending along the vertical direction is drawn on the diaper 1. Also, the length from the top of the absorbent body 20 to the bottom of the diaper 1 (the folded position) is divided into two equal parts, and a line C2 extending along the width direction is drawn on the diaper 1. The intersection of the two lines C1 and C2 is designated as the reference point o.

[0091] (2) In the torque testing machine, a pair of chucks 60 are arranged at a distance in the vertical direction, and the direction perpendicular to the vertical direction of the torque testing machine is the horizontal direction. The width W60 of the chucks 60 in the horizontal direction is approximately 25 mm. When the diaper 1 is set between the pair of chucks 60, the tension applied to the diaper 1 is 1 N. The lower chuck is fixed, and only the upper chuck moves up and down to adjust the tension. The load cell is set to 50 N of tension / compression, and the torque is set to 1 N.

[0092] (3) When twisting the diaper 1 around the imaginary axis Va1 along the width direction as shown in FIG. 8A, the gripping positions of the zippers 60 are set at positions p1 and p2, which are 30 mm to the right and left of the reference point o in the width direction, respectively. In other words, the zipper spacing is set to 60 mm. Specifically, the lower end of the upper zipper 60 is aligned with position p2 of the diaper 1, and the upper end of the lower zipper is aligned with position p1 of the diaper 1, so that the waist side of the diaper 1 is positioned on the right side in the horizontal direction. Furthermore, the center of the zipper 60 in the horizontal direction is aligned with the reference point o of the diaper 1. This allows the diaper 1 to be twisted around the imaginary axis Va1 along the width direction of the diaper 1 by gripping the vertical centers of both widthwise ends of the diaper 1 (more specifically, the vertical centers of the absorber 20).

[0093] (4) With the diaper 1 set as described above, rotate the upper zipper 60 clockwise (positive rotation) to twist the diaper 1 (twist the diaper 1 so that the waist portion of the diaper 1 in the right diagram of Figure 8A is facing the front of the page). Then, return it to its initial state, and rotate the upper zipper 60 counterclockwise (negative rotation) to twist the diaper 1 and return it to its initial state. When twisting around the imaginary axis Va1 along the width direction, the rotation speed is 50 rpm, the rotation angle is 65°, and the measurement angle is 60°. Calculate the average torque value (mN·m) when rotating clockwise at a measurement angle of 60° and when rotating counterclockwise at a measurement angle of 60°.

[0094] (5) When twisting the diaper 1 around the imaginary axis Va2 in the up-down direction as shown in Figure 8B, the gripping positions of the zippers 60 are set to positions p3 and p4, which are 50 mm above and below the reference point o in the up-down direction, respectively. In other words, the zipper spacing is set to 100 mm. Specifically, the lower end of the upper zipper 60 is aligned with position p3 of the diaper 1, and the upper end of the lower zipper 60 is aligned with position p4 of the diaper 1. The center of the zipper 60 in the horizontal direction is also aligned with the reference point o of the diaper 1. This allows the diaper 1 to be twisted around the imaginary axis Va2 in the up-down direction by gripping the widthwise center of both vertical end portions of the diaper 1.

[0095] (6) With the diaper 1 set as described above, rotate the upper zipper 60 clockwise (positive rotation) to twist the diaper 1 (twist the diaper 1 so that the right-hand portion of the diaper 1 in the width direction in the right diagram of Figure 8B is facing the front of the page). Then, return it to its initial state, and rotate the upper zipper 60 counterclockwise (negative rotation) to twist the diaper 1 and return it to its initial state. When twisting around the imaginary axis Va2 along the vertical direction, the rotation speed is 50 rpm, the rotation angle is 75°, and the measurement angle is 60°. Calculate the average torque value (mN·m) when rotating clockwise at a measurement angle of 60° and when rotating counterclockwise at a measurement angle of 60°.

[0096] (7) The torque value when twisting around the virtual axis Va1 (FIG. 8A) and the torque value when twisting around the virtual axis Va2 (FIG. 8B) are measured multiple times (e.g., n = 3 times) for each measurement. Regardless of the measurement direction, multiple measurements are not taken on the same diaper 1; a different diaper 1 is prepared for each torque measurement. Then, the average value of all the multiple (e.g., three) torque values around the virtual axis Va1 and the multiple (e.g., three) torque values around the virtual axis Va2 is calculated (rounded to one decimal place). This average value is the torque value of the diaper 1 (pants-type absorbent article) before absorption.

[0097] 10 to 12 are explanatory diagrams of modified examples of the diaper 1 (pants-type absorbent article). The diaper 1 has lateral elastic members that stretch in the width direction. In the case of the diaper 1 shown in Fig. 9, waist elastic members 33, 34 arranged along the width direction are provided on waist portions 30, 40 (outer body) as lateral elastic members.

[0098] The diaper 1 of the modified example shown in Fig. 10 has, as an exterior body, rectangular front waistband 30 and rear waistband 40 that overlap the side joint 2 in the vertical direction, and a generally trapezoidal buttocks-covering portion 45 that extends downward below the rear waistband 40. The buttocks-covering portion 45 covers the wearer's buttocks, providing a sense of security when wearing the diaper. The buttocks-covering portion 45 also increases the outer shape of the diaper 1, thereby reducing the user's anxiety about leakage. The buttocks-covering portion 45 shown in Fig. 10 is provided with a buttocks-side elastic member 451 arranged along the width direction. In this case, the diaper 1 has waistband elastic members 33, 43 and a buttocks-side elastic member 451 as "transverse elastic members." Not only the waistline elastic members 33, 43 but also the buttocks-side elastic member 451 (effective length portion) are cut at least in part of the portion overlapping the absorbent cores 21-24 in the thickness direction, so that no stretching force acts on them. This prevents the absorbent cores 21-24 from shrinking due to the buttocks-side elastic member 451, which would otherwise cause wrinkles. Note that the outer casing may also have a portion extending downward from the front waistline portion 30.

[0099] The diaper 1 of the modified example shown in FIG. 11 has a crotch section 70 connecting the front waistline section 30 and the rear waistline section 40, and is provided with an outer shell formed from a single continuous member. Inclined elastic members 71 are provided from the lower ends of the front waistline section 30 and the rear waistline section 40 to the crotch section. The inclined elastic members 71 have portions that slope downward from both sides of the front waistline section 30 and the rear waistline section 40 toward the center in the width direction. In this case, the diaper 1 has waistline elastic members 33, 43 and the inclined elastic member 71 as "transverse elastic members." Not only the waistline elastic members 33, 43, but also the inclined elastic member 71 (effective length portion) are cut at least in part of the portion that overlaps the absorbent cores 21-24 in the thickness direction, so that no stretching force is applied. This prevents the absorbent cores 21-24 from shrinking due to the inclined elastic members 71, which would otherwise cause wrinkles.

[0100] 9 to 11, the lateral elastic members are exemplified as thread-like elastic members, but are not limited thereto. The lateral elastic members may also be sheet-like elastic members (such as elastic nonwoven fabrics or elastic films).

[0101] Furthermore, it is preferable that the waist elastic members 33, 43 (effective length portions) which are transverse elastic members extend continuously from one end to the other in the width direction of a portion of the absorbent main body 10 where the absorbent cores 21-24 are not present, across the said portion in the width direction. For example, in the diaper 1 shown in Fig. 9, waist elastic members 33b, 43b which overlap with the ends of the absorbent main body 10 in the longitudinal direction are provided continuously in the width direction between a pair of side joint portions 2. It is sufficient that the waist elastic members 33, 43 are provided continuously in the width direction at the end of the absorbent main body 10 on at least one of the front and rear sides in the longitudinal direction.

[0102] This allows the longitudinal ends of the absorbent main body 10 to be closely fitted to the wearer's body by the waist elastic members 33b, 43b while suppressing shrinkage of the absorbent cores 21-24 in the width direction. This makes it difficult for gaps to form between the ends of the absorbent main body 10 and the wearer, thereby suppressing leakage of excrement (urine and feces). It also prevents the absorbent main body 10 from sagging after excretion. In addition, it prevents the absorbent main body 10 from protruding outside the diaper 1, giving the diaper 1 a neater appearance similar to that of underwear.

[0103] Furthermore, parts of the lateral elastic members may be located at the widthwise ends of the absorbent cores 21 to 24. For example, in the diaper 1 of Fig. 9, parts of the waist elastic members 33, 43 overlap with both widthwise side edges of the absorbent cores 21 to 24 in the thickness direction.

[0104] In this case, the waist elastic members 33, 43 stretched while the diaper 1 is being worn pull the widthwise ends of the absorbent cores 21-24 outward in the widthwise direction, thereby improving the flatness of the absorbent cores 21-24. This ensures the absorption area of the absorbent cores 21-24, reduces gaps between the absorbent cores 21-24 and the wearer, and suppresses leakage of body waste. Furthermore, unlike when the waist elastic members 33, 43 are positioned across the entire widthwise area of the absorbent cores 21-24, the contractile force acting on the absorbent cores 21-24 is suppressed, thereby suppressing shrinkage of the absorbent cores 21-24 in the widthwise direction.

[0105] However, without being limited to the above, as shown in Fig. 10, the lateral elastic members (here, the waist elastic members 33, 43 and the buttocks-side elastic member 451) may be positioned outside the outer periphery of the absorbent cores 21-24. In other words, the lateral elastic members may not overlap the absorbent cores 21-24 at all in the thickness direction. This makes it difficult for the contractile force of the lateral elastic members to act on the absorbent cores 21-24. This makes it possible to more reliably suppress shrinkage of the absorbent cores 21-24 in the width direction.

[0106] 9, in the unfolded and stretched state of the diaper 1, the front waistline portion 30 and the rear waistline portion 40 each have non-elasticated regions NEf and NEb where the waistline elastic members 33, 43 (effective length portions) are not located in the portions that overlap the absorbent main body 10 in the thickness direction. The widthwise length W1 of the non-elasticated region NEf of the front waistline portion 30 is preferably shorter than the widthwise length W2 of the non-elasticated region NEb of the rear waistline portion 40 (W1 <W2)。

[0107] This increases the effective length of the front waist elastic members 33, improving the fit of the front waist portion 30. This allows the front waist portion 30 to fit more closely to the wearer's rounded abdomen. When the diaper 1 is worn, the wearer's urethral opening abuts the front portion of the diaper 1. This improves the fit of the front portion of the diaper 1, which receives more urine, thereby reducing urine leakage. Meanwhile, the effective length of the rear waist elastic members 43 is shortened. This allows the fit of the rear waist portion 40 and the absorbent main body 10 to the wearer's buttocks to be moderated, ensuring sufficient space to accommodate feces.

[0108] When at least one of the front waistline portion 30 and the rear waistline portion 40 is vertically divided into four regions R1, R2, R3, and R4, starting from the bottom, as shown in Fig. 9. Each of the regions R1 to R4 is a rectangular region that is elongated in the width direction when the diaper 1 is in an unfolded and stretched state. In this case, it is preferable that the contractile force of the lowest region R1 is smaller than the contractile force of the second-lowest region R2.

[0109] The contractile force of the lowest region R1 is more likely to affect the portion of the absorbent cores 21-24 that contacts the wearer's crotch region than the contractile force of the second-lowest region R2. Therefore, by reducing the contractile force of region R1, it is possible to suppress the contraction of the portion of the absorbent cores 21-24 that receives body exudates, thereby ensuring an adequate absorption area. This in turn suppresses leakage of body exudates. In particular, the portion of the absorbent cores 21-24 that contacts the wearer's crotch region may have narrowed portions 212, 222 that are constricted inward in the width direction, or may be affected by the contractile force of the leg gather elastic members 17, making the absorbent cores 21-24 more likely to deform. Therefore, it is desirable to reduce the contractile force of the lowest region R1. On the other hand, rather than reducing the contractile force of the second-lowest region R2 to match that of the lowest region R1, the fit of the waistband portions 30, 40 can be improved by making the contractile force of region R2 greater than that of region R1.

[0110] (Method for measuring contractile force) The contraction force can be measured using a tensile tester (for example, an Instron (Model: 5965) or equivalent). First, the waist-lined portions 30, 40 are cut from the target diaper 1. The absorbent main body 10 is not separated from the waist-lined portions 30, 40, but is cut together with the absorbent main body 10 to prepare samples. The portions extending beyond the side joint portions 2 toward the crotch (e.g., buttocks cover portions) are not included in the cut samples. The waist-lined portions 30, 40 are cut in the width direction at intervals of 1 / 4 of the vertical length (L) of the side joint portions 2 (L / 4). Then, samples corresponding to the lowest region R1 and the second-lowest region R2 are cut out. Specifically, to measure the regions R1 and R2 of the front waistline portion 30 and the rear waistline portion 40, the side seam 2 is released, the waistline portions 30 and 40 are separated, and the regions R1 and R2 are cut out. Furthermore, with the diaper 1 in a stretched state (i.e., with the side seam 2 aligned in the vertical direction of the diaper 1), the measurement regions R1 and R2 are identified and cut out. As a result, the samples of the regions R1 and R2 have a rectangular shape that is elongated in the width direction in the stretched state. Next, the initial distance between the pair of chucks spaced apart in the tensile direction of the tensile tester is adjusted to match the length of the sample (a length that will not loosen the sample or will loosen it slightly). The stretch direction of the sample (here, the width direction of the diaper 1) is set as the tensile direction, and both ends of the sample in the stretch direction are fixed with chucks. The width by which the chucks grip the sample in the tensile direction is kept constant. Next, the distance between the pair of chucks is increased in the tensile direction at a predetermined speed (e.g., 100 mm / min). The sample is then stretched until it reaches a predetermined elongation state (e.g., 90% elongation), where the maximum elongation of the sample is 100%. The distance between the pair of chucks is then decreased at a predetermined speed (e.g., 100 mm / min) until it reaches a lower elongation state (e.g., 70% elongation) from the predetermined elongation state (e.g., 90%). The contractile force (unit: N) is the measured value at an intermediate contraction state (e.g., 80%) when the sample is contracted from the predetermined elongation state (e.g., 90%) to a lower elongation state (e.g., 70%). In other words, the contractile force is the force with which the sample returns to its original length from the stretched state. It is desirable to measure multiple samples and use the average value of the measured values for each sample as the contractile force.

[0111] Preferably, the force required to stretch the lowest region R1 by a unit length along the width direction in at least one of the front waistline portion 30 and the rear waistline portion 40 is smaller than the force required to stretch the second-lowest region R2 by a unit length along the width direction. In this case, shrinkage of the width of the portion of the absorbent cores 21-24 that receives bodily excrement can also be suppressed.

[0112] The "force required to stretch a unit length" can also be measured using the method described above using a tensile tester. Specifically, the stretch direction (here, the width direction) of the sample cut out from the target regions R1 and R2 is defined as the tensile direction, and both ends of the sample in the stretch direction are fixed with chucks. The pair of chucks are separated at a predetermined speed (e.g., 100 mm / min). The measured value (unit: N) when the sample is stretched from a predetermined stretch state (e.g., 70%) to a higher stretch state (e.g., 90%) is defined as the force required to stretch a unit length.

[0113] FIG. 13 is a schematic plan view of the absorbent main body 10. The diaper 1 has a pair of leg gathers that fit around the legs of the wearer. In the diaper 1 shown in FIGS. 3 and 13, the absorbent main body 10 has a pair of leg gathers LG on both sides in the width direction. As shown in FIG. 3, the region from one end of the absorber 20 to one end of the absorbent main body 10 in the width direction is called the leg gathers LG. The leg gathers LG are provided with leg gather elastic members 17 in their stretch direction (here, the vertical direction (longitudinal direction) of the diaper 1). In FIG. 3, six leg gather elastic members 17a to 17f (thread elastic) are provided lined up in the width direction. The provision of the leg gathers LG in the absorbent main body 10 allows the diaper 1 to fit closely around the legs of the wearer, thereby preventing leakage of body waste from the legs. The number of leg gather elastic members 17 is not particularly limited and may be one or more. Furthermore, the leg gather elastic members 17 are not limited to thread-like elastic members, but may be sheet-like elastic members.

[0114] The extension ratio of the leg gather elastic members 17 is preferably 2.4 or less. The extension ratio is defined as the longitudinal length La of the leg gather elastic members 17 when the leg gather portions LG are fully extended (when the diaper 1 is unfolded and extended) divided by the length Lb of the leg gather elastic members 17 in the unloaded state (when the diaper 1 is in its natural state), i.e., La / Lb. The extension ratio of at least one of the leg gather elastic members 17 in the diaper 1 should be 2.4 or less, and preferably all of the leg gather elastic members 17 should be 2.4 or less.

[0115] By setting the extension ratio of the leg gather elastic members 17 to 2.4 times or less, shrinkage of the absorbent cores 21-24 in the stretch direction of the leg gather portions LG (here, the vertical direction) can be suppressed compared to when the extension ratio of the leg gather elastic members 17 is greater than 2.4 times. Even if the absorbent cores 21-24 have a low torque value and are flexible, as in the diaper 1 of this embodiment, ensuring the vertical length of the absorbent cores 21-24 before use can alleviate the user's concerns about tightness and leakage. Furthermore, shrinkage of the absorbent cores 21-24 in the vertical direction and their protrusion to the outside of the diaper 1 can be suppressed. This allows the diaper 1 to have a neat appearance similar to that of underwear.

[0116] Preferably, the number of leg gather elastic members 17 in the diaper 1 is between one and six, and the thickness is between 310 dtex and 780 dtex. For example, as shown in Fig. 10, three or fewer leg gather elastic members 17 may be provided on each side of the absorbent main body 10 in the width direction. This reduces the contraction of the leg gathers and suppresses shrinkage of the diaper 1 in the vertical direction. This allows the apparent dimensions of the diaper 1 before use to be maintained large, providing a sense of security to the user.

[0117] In the diaper 1 illustrated in Figs. 9 and 10, leg gathers LG are formed along the wearer's legs by leg gather elastic members 17 provided along the longitudinal direction on both widthwise sides of the absorbent main body 10. Furthermore, leg gathers LG2 are also formed along the wearer's legs by inclined elastic members 71 shown in Fig. 11. That is, the inclined elastic members 71 also correspond to leg gather elastic members arranged along the stretch direction of the leg gathers LG2 (a direction inclined relative to the widthwise and longitudinal directions in Fig. 11). Therefore, it is preferable that the elongation ratio of the inclined elastic members 71 is 2.4 times or less. This can suppress shrinkage of the absorbent cores 21-24 in the widthwise and longitudinal directions.

[0118] 11, in addition to the inclined elastic members 71, leg gather elastic members 17 are also provided along the longitudinal direction, but this is not limiting and the diaper 1 may not have leg gather elastic members 17 along the longitudinal direction. Even in this case, the inclined elastic members 71, which are leg gather elastic members, allow the diaper 1 to fit snugly around the legs of the wearer.

[0119] Furthermore, it is preferable that the contractile force of the leg gathers LG (here, the contractile force in the vertical direction) is smaller than the contractile force of the leakage preventing walls 3 in the vertical direction. Reducing the contractile force of the leg gathers LG can reduce the shrinkage (here, the contractile force in the vertical direction) of the highly flexible absorbent cores 21-24. This reduces the user's anxiety about tightness and leakage and prevents the absorbent cores 21-24 from protruding. Meanwhile, the leakage preventing walls 3 stand upright against the skin of the absorbent cores 21-24. Therefore, the contractile force of the leakage preventing walls 3 has less effect on the absorbent cores 21-24 than the contractile force of the leg gathers LG. Therefore, increasing the contractile force of the leakage preventing walls 3 can reduce the shrinkage of the absorbent cores 21-24 in the vertical direction while allowing the leakage preventing walls 3 to stand upright against the skin. Therefore, the leakage preventing walls 3 can effectively block body exudates, and even if the contractile force of the leg gathers LG is reduced, leakage of body exudates from around the legs can be prevented.

[0120] The contractile force of the leg gathers LG and the leakage barrier walls 3 can also be measured using the method using the tensile tester described above. The forces of the leakage barrier walls 3 and leg gathers LG located on one or both sides in the left-right direction are compared. Specifically, the leg gathers LG and the leakage barrier walls 3 are each cut out as samples from the diaper 1. The stretch direction of the sample (here, the longitudinal direction of the diaper 1) is set as the tensile direction, and the sample is placed between a pair of zippers. The sample is then contracted from a predetermined elongation state (e.g., 90%) to a lower elongation state (e.g., 70%), and the measured values at an intermediate contraction state (e.g., 80%) are compared as contractile force (unit: N).

[0121] The outer longitudinal range is cut out by a predetermined length (the gripping margin of the chuck of the tensile tester) from each end of the longitudinal direction of the effective length portion of the leg gather elastic member 17 constituting the leg gather portion LG. The widthwise range of the leakage preventing wall portion 3 is measured from the tip (the inner widthwise end of the side sheet 15) to the rising point, as shown in FIG. 3. The rising point is the inner widthwise end of the adhesive HMA that secures the side sheet 15 to the skin-facing side of the top sheet 12, etc. The outer longitudinal range is cut out by a predetermined length from each end of the effective length portion of the leakage preventing wall elastic member 16 constituting the leakage preventing wall portion 3.

[0122] Preferably, the force required to stretch the leakage barrier wall portions 3 by a unit length along the longitudinal direction is greater than the force required to stretch the leg gathers LG by a unit length along the stretch direction. In this case, the leakage barrier wall portions 3 can also suppress the longitudinal contraction of the absorbent cores 21-24 while suppressing leakage of body waste. The force required to stretch by this unit length can also be measured using the same method using the tensile tester described above. Specifically, the force required to stretch by this unit length is determined by the measured value (unit: N) when the leakage barrier wall portions 3 and the leg gathers LG are each stretched from a predetermined stretched state (e.g., 70%) to a higher stretched state (e.g., 90%).

[0123] The contractile force of the leg gather portion LG2 formed by the inclined elastic member 71 (see FIG. 11 ) can also be measured in a similar manner. In this case, the effective length portions (e.g., the area indicated by the dashed line in FIG. 11 ) of one or more (here, three) inclined elastic members 71 located below the waist elastic members 33, 43 and outboard of the absorbent main body 10 in the width direction are preferably cut out as samples. However, if the sample is short, it may be cut out longer than the above range. The portions where the inclined elastic member 71 intersects with the waist elastic members 33, 43 and where it overlaps with the absorbent main body 10 are gripped with the chuck of the tensile tester. When measuring the contractile force of a leg gather elastic member (inclined elastic member 71) alone, as described below, the effective length portion of one inclined elastic member 71 located within the above range is preferably cut out as a sample. The sample is set in the tensile tester so that the stretch direction of the inclined elastic member 71 is aligned with the tensile direction of the tensile tester.

[0124] The leg gather portion LG shown in Fig. 13 has multiple (six) leg gather elastic members 17a-17f arranged side by side in the width direction. In this case, it is preferable that the contractile force of the leg gather elastic member 17a arranged at the innermost position in the width direction (the direction perpendicular to the stretch direction of the leg gather portions LG and LG2) is greater than the contractile force of the leg gather elastic member 17f arranged at the outermost position. Similarly, it is preferable that the contractile force of the inclined elastic member 71a arranged at the innermost position (the position farthest from the edge of the outer garment) of the three inclined elastic members 71 (leg gather elastic members) shown in Fig. 11 is greater than the contractile force of the inclined elastic member 71b arranged at the outermost position (the position closest to the edge of the outer garment).

[0125] This allows the contractile force of the widthwise innermost leg gather elastic members 17a to firmly fit the diaper 1 around the wearer's legs, thereby preventing side leakage of body exudates. Furthermore, as shown in FIG. 1, the widthwise inner edges of the leg gathers LG tend to rise (the outer sheet 14 is pushed upward). This allows the wide leg gathers LG to easily spread outward in the widthwise direction, flattening the diaper 1 around the wearer's legs, ensuring a smooth, even fit. Meanwhile, by reducing the contractile force of the widthwise outermost leg gather elastic members 17f, vertical contraction of the absorbent cores 21-24 can be prevented.

[0126] Conversely, in the width direction (the direction perpendicular to the stretch direction of the leg gather portions LG, LG2), the contractile force of the innermost leg gather elastic member 17a may be smaller than the contractile force of the outermost leg gather elastic member 17f. Similarly, it is preferable that the contractile force of the innermost inclined elastic member 71a of the three inclined elastic members 71 (leg gather elastic members) shown in Figure 11 is smaller than the contractile force 71b of the outermost inclined elastic member 71.

[0127] In this case, the contractile force of the leg gather elastic members 17a closest to the absorbent cores 21 to 24 is suppressed, effectively suppressing vertical contraction of the absorbent cores 21 to 24. On the other hand, by increasing the contractile force of the outermost leg gather elastic members 17f, which are less likely to affect the absorbent cores 21 to 24, the leg gather portions LG can be fitted around the wearer's legs, thereby suppressing leakage of body waste.

[0128] The contractile force can be measured in the same manner as described above. Specifically, each target leg gather elastic member 17 is cut out as a sample. The sample is then contracted from a predetermined stretched state (e.g., 90%) to a lower stretched state (e.g., 70%), and the measured value (unit: N) at an intermediate stretched state (e.g., 80%) is compared as the contractile force. The sample is cut out along the edge of the target leg gather elastic member 17. Furthermore, a predetermined length (the gripping margin of the chuck of the tensile tester) is cut out from both ends of the effective length of the target leg gather elastic member 17 in the longitudinal direction outward as a sample.

[0129] Furthermore, the force required to stretch the innermost leg gather elastic member 17a, 71a by a unit length in the stretch direction may be greater or smaller than the force required to stretch the outermost leg gather elastic member 17f, 71b by a unit length in the stretch direction. In this case, the force can be measured using the same method using the tensile tester described above. Specifically, the force required to stretch the target leg gather elastic member 17 by a unit length is determined by the measured value (unit: N) when the target leg gather elastic member 17 is stretched from a predetermined stretch state (e.g., 70%) to a higher stretch state (e.g., 90%).

[0130] So far, we have explained the contractile force of the waist portion 30, 40, the leg gathered portion LG, the leakage preventing wall portion 3, etc., but the contractile force can be adjusted by adjusting the elongation ratio of the elastic member, the thickness of the elastic member, the spacing between the elastic members in the direction perpendicular to the stretching direction, the length of the effective length portion of the elastic member, etc.

[0131] When the diaper 1 is in an unfolded and stretched state, the region from the end of the absorbent cores 21-24 (here, the end 21e of the skin side layer 21) in the width direction to the end 10e of the absorbent main body 10 is divided into three regions (see FIG. 13), which are designated as regions r1, r2, and r3 in order from the innermost region in the width direction. In this case, it is preferable that the leg gather elastic members 17 are not provided in the innermost region r1 in the width direction.

[0132] Since the leg gather elastic members 17 are not provided in the region r1 close to the absorbent cores 21 to 24, the contractile force of the leg gather elastic members 17 is less likely to affect the absorbent cores 21 to 24. As a result, shrinkage of the absorbent cores 21 to 24 in the vertical direction can be further suppressed.

[0133] 13, the leg gather portion LG is provided with three or more leg gather elastic members 17 that are stretchable in the up-down direction (longitudinal direction). When the diaper 1 is in an unfolded and stretched state, the region between the innermost leg gather elastic member 17a and the outermost leg gather elastic member 17f in the width direction is defined as a leg gather elastic region ER. When the leg gather elastic region ER is divided into two equal parts in the width direction, the inner region is defined as an inner leg gather elastic region ERi, and the outer region is defined as an outer leg gather elastic region ERo. In this case, it is preferable that the average value Ave1 of the length of the portion (effective length portion) on which an elastic force acts in the longitudinal direction for the leg gather elastic members 17a to 17c arranged in the inner leg gather elastic region ERi is shorter by 10% or more than the average value Ave2 of the length of the portion (effective length portion) on which an elastic force acts in the longitudinal direction for the leg gather elastic members 17d to 17f arranged in the outer leg gather elastic region ERo (Ave1≦Ave2×90%).

[0134] Specifically, in Fig. 13, the length L6 of the two inner leg gather elastic members 17a, 17b in the width direction is shorter than the length L7 of the four outer leg gather elastic members 17c-17f. The average value Ave1 is the average value of the two short leg gather elastic members 17a, 17b and the one long leg gather elastic member 17c (=L6×2+L7 / 3). The average value Ave2 is the average value of the three long leg gather elastic members 17d-17f (=L7).

[0135] The contractile force of the inner leg gathered elastic region ERi is more likely to affect the absorbent cores 21-24 than the contractile force of the outer leg gathered elastic region ERo. Furthermore, the longer the effective length of the leg gathered elastic member 17, the more likely the contractile force of the leg gathered elastic member 17 will affect a wider longitudinal range of the absorbent cores 21-24. Therefore, by making the inner average value Ave1 10% or more shorter than the outer average value Ave2, it is possible to suppress the shrinkage of the absorbent cores 21-24 in the vertical direction compared to when the inner average value Ave1 is longer than 90% of the outer average value Ave2.

[0136] Furthermore, the rigidity of the region where the leg gather elastic members 17 are arranged increases. Therefore, the inner average value Ave1 decreases, and the rigidity of the inner leg gather elastic region ERi becomes lower than the rigidity of the outer leg gather elastic region ERo. Therefore, the contraction force of the outer leg gather elastic region ERo makes the inner leg gather elastic region ERi more likely to contract, and the cushioning provided by this region ERi further suppresses deformation of the absorbent cores 21-24.

[0137] 13, the front ends of the leg gather elastic members 17a and 17b located in the inner leg gather elastic region ERi are located further rearward than the front ends of the leg gather elastic members 17d to 17f located in the outer leg gather elastic region ERi. Therefore, the front regions of the absorbent cores 21 to 24 are less susceptible to the contractile force of the leg gather elastic members 17 than the rear regions. This ensures that the width and length of the front regions of the absorbent cores 21 to 24 that come into contact with the wearer's urethral opening can be secured. This helps prevent leakage and provides a sense of security to the user.

[0138] 9, it is preferable that the leg gather elastic members 17 (effective length portions) and the front and rear waist elastic members 33, 43 (effective length portions) have an intersecting region. This allows the elastic members (the leg gather elastic members 17 and the waist elastic members 33, 43) to be continuously arranged at the ends along the leg openings LH of the pants-type diaper 1. This allows the diaper 1 to fit snugly around the wearer's legs, preventing leakage.

[0139] 12, both longitudinal ends of the leg gather elastic members 17 (effective length portions) may be located closer to the longitudinal center (crotch area) than the front and rear waist elastic members 33, 43. This prevents the formation of an area where both the longitudinal contraction force of the leg gather elastic members 17 and the widthwise contraction force of the waist elastic members 33, 43 act directly, thereby suppressing shrinkage of the absorbent cores 21-24.

[0140] As shown in Figure 3, the absorbent body 10 has a core wrap sheet 25 (skin-side core wrap sheet portion) that covers at least a portion of the skin-facing side of the absorbent cores 21-24, a top sheet 12 (surface sheet) that is provided closer to the skin than the core wrap sheet 25, a core wrap sheet 26 (non-skin-side core wrap sheet portion) that covers at least a portion of the non-skin-facing side of the absorbent cores 21-24, and a back sheet 13 (back sheet) that is provided closer to the skin than the core wrap sheet 26. In this case, it is preferable to have a portion Ra where the top sheet 12 and the back sheet 13 are bonded. Specifically, it is preferable that the non-skin-side side of the top sheet 12 and the skin-facing side of the back sheet 13 are bonded.

[0141] As a result, both widthwise ends of the top sheet 12 are not folded back inward in the widthwise direction and away from the skin. In other words, the top sheet 12 is not folded back so as to wrap around the absorber 20. Since the top sheet 12 is not folded back, the rigidity around the widthwise side edges of the absorber 20 can be reduced, and the torque value of the diaper 1 before absorption can be reduced. In addition, the thickness of the absorbent cores 21-24 is reduced, which prevents the absorbent cores 21-24 from protruding outside the diaper 1. This gives the diaper 1 a neat appearance similar to that of underwear.

[0142] 3, both widthwise ends of the core wrap sheet 25 on the skin side are folded inward in the widthwise direction and toward the non-skin side. This increases the rigidity of the absorbent body 20 around the sides in the widthwise direction by the amount of the core wrap sheet 25 folded back. In this case, the absorbent body 20 is less likely to shrink due to the contractile force of the leg gather elastic members LG.

[0143] Alternatively, the skin-side core wrap sheet 25 may not be folded back, and the skin-side core wrap sheet 25 (non-skin side) and the non-skin-side core wrap sheet 26 (skin side) may be adhered together. In this case, the stiffness of the absorbent body 20 around the widthwise side can be reduced by the amount that the skin-side core wrap sheet 25 is not folded back, and the torque value of the diaper 1 before absorption can be further reduced.

[0144] Furthermore, the core wrap sheets 25, 26 are preferably sheets made of pulp fibers (such as tissue). By doing so, after absorbing excrement, hydrogen bonds are formed between the core wrap sheets 25, 26 and the absorbent cores 21-24, increasing the rigidity of the absorbent cores 21-24. As a result, shrinkage of the absorbent cores 21-24 can be further suppressed.

[0145] Furthermore, it is preferable that the length L3 (see FIG. 1) from the top to the bottom in the vertical direction of the pants-type diaper 1 in the natural state before absorption is at least 85.3% of the length L4 from the top to the bottom in the vertical direction of the pants-type diaper 1 in the maximum stretched state (L3≧L4×85.3%). Specifically, as shown in FIG. 2, the length L4 is half the length L5 in the longitudinal direction of the pants-type diaper 1 in the unfolded and stretched state (L4=L5 / 2).

[0146] As a result, the vertical length of the pants-type diaper 1 in its natural state is ensured compared to when the length L3 is less than 85.3% of the length L4. Therefore, even with a diaper 1 having a low torque value, the apparent dimensions (vertical length) of the diaper 1 before use are ensured, thereby reducing the user's concerns about tightness and leakage. Furthermore, ensuring the vertical length of the diaper 1 also prevents the absorbent cores 21-24 from protruding into the diaper 1.

[0147] In this specification, the unloaded state of the diaper 1 after it has been left for a predetermined period of time is referred to as the "natural state." For example, the diaper 1 is removed from the package and the waistbands 30, 40 are pulled outward in both the left and right directions to create a "stretched state." After this stretched state is maintained for 15 seconds, the tension on the diaper 1 is released and the diaper 1 is placed on a flat surface such as a desk. The state after the diaper 1 has been left lying flat for 5 minutes is referred to as the "natural state."

[0148] The absorbent cores 21 to 24 have a basis weight (basis weight of the liquid absorbent fiber 201 or SAP: g / m 2 ) is lower than the surrounding area. When the absorbent cores 21 to 24 have a plurality of absorbent layers, it is preferable that at least one of the plurality of absorbent layers has a low basis weight region.

[0149] In the absorbent cores 21-24 illustrated in Figs. 4-6, the skin-side layer 21, intermediate layer 22, and non-skin-side layer 23 have low basis weight regions 211, 221, 231. In the skin-side layer 21 and the intermediate layer 22 (see Fig. 6A), two low basis weight regions 211, 221, each having a substantially rectangular shape elongated in the longitudinal direction, are arranged symmetrically across the center line CL2 in the width direction at positions that come into contact with the wearer's crotch region. In the non-skin-side layer 23 (Fig. 6B), three rectangular divided regions 23a-23c elongated in the longitudinal direction are arranged side by side with a gap in the width direction. Two regions between these three divided regions 23a-23c form low basis weight regions 231 (slits).

[0150] The low basis weight regions 211, 221, and 231 in the absorbent cores 21-24 increase the flexibility of the absorbent cores 21-24, thereby reducing the torque of the diaper 1 before absorption. Furthermore, the low basis weight regions 211, 221, and 231 act as folding points, making it easier for the absorbent cores 21-24 to deform into a desired shape, improving the fit to the wearer.

[0151] Furthermore, the low basis weight regions 211, 221, 231 allow excreted liquid to be quickly drawn into the absorbent body 20. This allows the absorbent core 20 to be effectively utilized in the thickness direction. In the absorbent body 20 illustrated in FIG. 4, excreted liquid is quickly drawn from the low basis weight regions 211 of the skin-side layer 21 to the intermediate layer 22. The liquid-absorbent fiber 201 has a faster liquid absorption rate than SAP. Because the volume occupancy of the liquid-absorbent fiber 201 is high in the intermediate layer 22, the excreted liquid that has migrated from the low basis weight regions 211 to the intermediate layer 22 is quickly and temporarily absorbed by the intermediate layer 22. Thereafter, the excreted liquid absorbed between the fibers of the liquid-absorbent fiber 201 in the intermediate layer 22 gradually migrates to the non-skin-side layer 23 due to gravity. Furthermore, because the intermediate layer 22 also has a low basis weight region 221, excreted liquid easily migrates from the low basis weight region 221 to the non-skin side layer 23, and from the low basis weight region 231 of the non-skin side layer 23 to the deeper side of the non-skin side layer 23. This makes it easier to draw excreted liquid deep into the absorbent core, improving absorbency. Furthermore, because the volume occupancy of SAP is high in the non-skin side layer 23, excreted liquid is firmly absorbed and retained by the SAP of the non-skin side layer 23.

[0152] The low basis weight region may be a slit, a region where the absorbent core is recessed in the thickness direction, or a region where the absorbent core has a lower density but the thickness is the same. The shape, size, number, and location of the low basis weight region are not particularly limited. The low basis weight region may be located on the center line of the absorbent cores 21-24 in the width direction, or multiple low basis weight regions may be located at intervals in the longitudinal direction. Preferably, the low basis weight region is located at the position where the wearer's urinary excretion opening comes into contact and in the vicinity thereof.

[0153] 5, it is preferable that the low basis weight regions 211, 221, and 231 of each layer at least partially overlap each other in the thickness direction in a plan view of the absorbent cores 21-23. This allows the excreted liquid to easily flow into the low basis weight regions 211, 221, and 231 of each layer, and is easily drawn quickly to the deep side of the absorbent cores 21-24.

[0154] As described above, when the diaper 1 is in an unfolded and stretched state, the front waistline portion 30 and the rear waistline portion 40 each have non-elasticated regions NEf, NEb in areas where they overlap the absorbent main body 10 in the thickness direction, where the waistline elastic members 33, 43 (effective length portions) are not located. As shown in Fig. 9, the non-elasticated regions NEf, NEb of at least one of the front waistline portion 30 and the rear waistline portion 40 (here, both) preferably overlap the low basis weight regions 211, 221, 231 of the absorbent cores 21-24 in the width direction and extend outward in the width direction beyond the low basis weight regions 211, 221, 231. In other words, the non-elasticated regions NEf, NEb should be located outward beyond the outer widthwise ends 231e of the low basis weight regions 211, 221, 231.

[0155] This reduces the effect of the contractile force of the waist elastic members 33, 43 on the parts of the absorbent cores 21-24 that are easily deformed by the low basis weight regions 211, 221, 231. This makes it possible to suppress shrinkage of the absorbent cores 21-24 in the width direction.

[0156] 5, the absorbent cores 21-24 preferably have constricted portions 212, 222 constricted on the inner side in the width direction in the crotch portion that is located between the crotch of the wearer when worn. When the absorbent cores 21-24 have multiple absorbent layers, it is preferable that at least one of the multiple absorbent layers has a constricted portion. In this embodiment, the skin side layer 21 and the intermediate layer 22 have the constricted portions 212, 222. When the skin side layer 21 and the intermediate layer 22 are divided into thirds at the maximum length in the longitudinal direction, the central region is defined as the longitudinal center, and it is preferable that at least a part of the constricted portions 212, 222 is located there.

[0157] The absorbent cores 21-24 have the constricted portions 212, 222, which increases the flexibility of the absorbent cores 21-24 and reduces the torque value of the diaper 1 before absorption. Furthermore, the force of the wearer's legs pinching the absorbent cores 21-24 is prevented from acting too strongly on the absorbent cores 21-24. This prevents the absorbent cores 21-24 from being distorted uncontrollably by the pinching force of the legs, improving the fit of the absorbent cores 21-24 around the wearer's crotch region.

[0158] As shown in Fig. 5, the constricted portions 212, 222 of the absorbent cores 21-24 have the narrowest point SA where the width H5 is shortest. As shown in Fig. 9, it is preferable that the widthwise outer edge of at least one of the non-elasticated regions NEf, Nbf of the front waistline portion 30 and the back waistline portion 40 is located widthwise outer than the narrowest point SA of the constricted portions 212, 222, or is aligned with the widthwise position of the narrowest point SA.

[0159] When the narrowest point SA is located on one side of the longitudinal centerline CL of the diaper 1 in the longitudinal direction (the front side in Fig. 9), it is more desirable that the positional relationship between the non-elasticated region of the waistline portion on one side (the front waistline portion 30 in Fig. 9) and the narrowest point SA be as described above. In Fig. 9, the widthwise outer edge NEf1 of the front non-elasticated region NEf is aligned with the widthwise position of the narrowest point SA, and the widthwise outer edge NEb1 of the rear non-elasticated region NEb is located widthwise outboard of the narrowest point SA.

[0160] In this case, the contractile force of the waist elastic members 33, 43 is less likely to affect the portions of the absorbent cores 21-24 that are widthwise inward of the constricted portions 212, 222. This prevents the absorbent cores 21-24 from being pinched by the wearer's legs along the constricted portions 212, 222, and the resulting deformation of the absorbent cores 21-24 (deformation along the wearer's crotch area and deformation due to folding in the low basis weight regions 211, 221, 231) from being hindered by the waist elastic members 33, 43. This maintains the fit of the absorbent cores 21-24 around the wearer's crotch area.

[0161] Conversely, as shown in a modified example in Fig. 12, the widthwise outer ends NEf1, NEb1 of at least one of the non-elasticated regions NEf, NEb of the front waistline portion 30 and the rear waistline portion 49 may be located widthwise inward of the narrowest point SA of the constricted portions 212, 222. When the narrowest point SA is located on one longitudinal side (the front side in Fig. 12) of the longitudinal centerline CL of the diaper 1, it is more desirable that the positional relationship between the non-elasticated region of one waistline portion (the front waistline portion 30 in Fig. 12) and the narrowest point SA be as described above.

[0162] In this case, the stretching force of the waist elastic members 33, 43 is likely to affect the portions of the absorbent cores 21-24 that are widthwise inward of the constricted portions 212, 222. Therefore, even when the wearer's legs tightly pinch the absorbent cores 21-24, the waist elastic members 33, 43 pull the constricted portions 211, 221 of the absorbent cores 21-24 outward in the widthwise direction. This prevents the absorbent cores 21-24 from shrinking in the widthwise direction in the crotch area, ensuring the absorption area of the absorbent cores 21-24. This prevents leakage of excrement.

[0163] However, the absorbent cores 21-24 may not have constricted portions. Furthermore, as shown in Fig. 5, the non-skinside layer 23 may extend outward in the width direction from the constricted portions 212, 222 of the skinside layer 21 and the intermediate layer 22. This allows the non-skinside layer 23 to absorb excrement that is not fully absorbed by the skinside layer 21 and the intermediate layer 22, thereby preventing leakage. Furthermore, since the number of layers is reduced in the extending portions of the non-skinside layer 23, the wearer's legs are less likely to feel uncomfortable when the absorbent cores 21-24 are pinched between them.

[0164] Furthermore, in the width direction, the maximum lengths of the skin side layer 21 and the intermediate layer 22 are preferably longer than the maximum length of the non-skin side layer 23. This allows excreted fluid to be absorbed and diffused more effectively in the area closer to the skin than the non-skin side layer 23.

[0165] The maximum thickness T20 (see FIG. 4) of the absorbent body 20 including the absorbent cores 21-24 is preferably 3.0 mm or less. The maximum thickness of the absorbent cores 21-24 (the total thickness of the layers 21-24) is preferably 2.5 mm or less.

[0166] This increases the flexibility of the absorber 20 and reduces the torque value of the diaper 1 before absorption, compared to when the maximum thickness of the absorber 20 is greater than 3.0 mm. This also reduces stiffness of the absorber 20, improving the comfort of wearing the diaper 1. It also reduces protrusion of the absorber 20 to the outside of the diaper 1, giving the diaper 1 a neater appearance similar to that of underwear.

[0167] The skin-side layer 21 has a first thickness t1, the intermediate layer 22 has a second thickness t2, and the non-skin-side layer 23 has a third thickness t3 (see FIG. 4 ), where the first thickness t1 to the third thickness t3 refer to average thicknesses. In this embodiment, the third thickness t3 of the non-skin-side layer 23 is thicker than the first thickness t1 of the skin-side layer 21. Specifically, the third thickness t3 of the non-skin-side layer 23 is preferably 0.38 mm to 0.58 mm for the S-size diaper 1 and preferably 0.58 mm to 0.69 mm for the XXL-size diaper 1. The first thickness t1 of the skin-side layer 21 is preferably 0.3 mm to 0.48 mm for the S-size diaper 1 and preferably 0.45 mm to 0.65 mm for the XXL-size diaper 1. The skin-side layer 21, which is thinner than the non-skin-side layer 23, also becomes thinner after moisture retention. That is, even after water retention, SAP swelling is unlikely to cause absorption inhibition, and the feel (gritty feeling) of the diaper 1 on the skin side is unlikely to deteriorate.

[0168] The average thickness t2 of the intermediate layer 22 is preferably 0.5 mm or more. More preferably, it is 0.9 mm to 1.1 mm for an S-size diaper 1 and 1.28 mm to 1.61 mm for an XXL-size diaper 1. This allows for more excreted liquid to be absorbed between the fibers of the liquid-absorbent fibers 201 of the intermediate layer 22 than when the average thickness of the intermediate layer 22 is less than 0.5 mm, for example, compared to when the intermediate layer 22 is a nonwoven fabric (sheet member) formed of pulp fibers or the like. Therefore, the excreted liquid can be quickly and temporarily absorbed in the intermediate layer 22, and after diffusing in the intermediate layer 22, the excreted liquid is quickly transferred to the non-skin-side layer 23, ensuring absorbency. However, if the intermediate layer 22 is too thick, it may feel bulky, so the average thickness (second thickness t2) of the intermediate layer 22 is preferably 2.5 mm or less.

[0169] The thicknesses (t1 to t3) of the absorbent body 20 and the layers 21 to 23 constituting the absorbent core can be measured using well-known methods. For example, with the diaper 1 in a natural, dry state without external force, the diaper 1 (absorbent body 20) is cut widthwise at any longitudinal position of the portion of the diaper 1 where the absorbent body 20 is located, specifically, at a location where the three layers 21 to 23 are stacked and away from the product folding position. To prevent damage to the components of the absorbent body 20, the diaper 1 is cut at a predetermined location and measured. Next, using an optical microscope (e.g., Keyence VHX-7000 Digital Microscope or equivalent), the cut surface is placed upright in front of the microscope and magnified (e.g., 30 to 100 times) and photographed. The focus of the magnified photograph is on the liquid-absorbent fiber 201. In the captured cross-sectional image, the layer in which the liquid-absorbent fiber 201 is visible is determined to be the intermediate layer 22, and the portions of the absorbent core closer to the skin or closer to the skin are determined to be the skin-side layer 21 and the non-skin-side layer 23, respectively. Furthermore, measurement positions (e.g., five positions) are determined in the width direction of the cross-sectional image, and the thickness of each of the layers 21 to 23 at each measurement position is obtained. Preferably, cross-sectional images are captured at multiple positions in the longitudinal direction of the absorbent body 20 to obtain the thickness of each of the layers 21 to 23. The average value of the obtained thicknesses is calculated for each of the layers 21 to 23, and this is defined as the average thickness t1 of the skin-side layer 21 (first thickness t1), the average thickness t2 of the intermediate layer 22 (second thickness t2), and the average thickness t3 of the non-skin-side layer 23 (third thickness t3). When measuring the thickness, portions other than the low basis weight regions 211, 221, and 231 are measured.

[0170] Using the above-mentioned method, five samples were prepared by cutting the longitudinal end of the absorbent body 20 and then cutting the absorbent body 20 so that the longitudinal length was 10 mm from that point.The average thicknesses when measured were as follows: for size S, the first thickness t1 was 0.41 mm, the second thickness t2 was 0.99 mm, and the third thickness t3 was 0.47 mm; and for size XXL, the first thickness t1 was 0.56 mm, the second thickness t2 was 1.47 mm, and the third thickness t3 was 0.63 mm.

[0171] Furthermore, the absorbent cores 21-24 preferably have a plurality of compressed portions formed so as to partially compress the absorbent cores 21-24 in the thickness direction. The skin-side layer 21 of the absorbent body 20 shown in FIG. 7 has a plurality of compressed dots 50 formed so as to compress the skin-side layer 21 in a dotted pattern in the thickness direction. These "compressed dots 50" result in the skin-side layer 21 being compressed in the thickness direction by embossing. The compression increases the fiber density of the skin-side layer 21 (absorbent core) compared to uncompressed portions. In this embodiment, the compressed dots are formed as a collection of dots (circles), but the compressed dots may also be formed as lines (straight lines, curves), for example. Alternatively, the compressed dots or lines may be formed discretely within a predetermined region. Furthermore, as a pattern for forming the compressed dots, FIG. 7 illustrates an arrangement pattern in which the compressed dots 50 appear as a dotted grid pattern (a so-called quilting pattern) as a whole, but other patterns may also be used.

[0172] By locally compressing the absorbent cores 21-24 with the compressed portions, it is possible to prevent the absorbent cores 21-24 from collapsing without impairing the flexibility of the absorbent cores 21-24. In other words, the rigidity of the absorbent cores 21-24 is appropriately increased, and deformation (shrinkage) of the absorbent cores 21-24 can be suppressed. Note that the skin side layer 21 need not necessarily be provided with a plurality of compressed points 50, as long as at least one of the skin side layer 21 and the non-skin side layer 23 has compressed points 50. Furthermore, the intermediate layer 22 may also be compressed.

[0173] 4, the absorbent cores 21-24 of this embodiment each have a plurality of absorbent layers, each of which includes an integrally formed skin-side layer 21, an intermediate layer 22 (second absorbent layer), and a non-skin-side layer 23 (first absorbent layer). In this case, as shown in Fig. 5 and Fig. 9, when the diaper 1 is in an unfolded and stretched state, it is preferable that the rear end 23e of the non-skin-side layer 23 is located closer to the center in the longitudinal direction than the rear ends 21e, 22e of the skin-side layer 21 and the intermediate layer 22.

[0174] Because the length of the non-skin-side layer 23 extending from the longitudinal center CL of the absorbent cores 21-24 toward the back is short, the number of layers is fewer and the thickness is thinner in the back portions of the absorbent cores 21-24 than in other portions. This reduces the rigidity of the back portions (back portions) of the absorbent cores 21-24. This prevents the absorbent cores 21-24 from feeling stiff to the user when lying on their back or sitting. On the other hand, the front portions (ventral portions) of the absorbent cores 21-24 come into contact with the wearer's urethral opening when worn and receive a large amount of excreted fluid. Therefore, by increasing the number of layers of the absorbent core in the front portions of the absorbent cores 21-24 compared to the back portions, excreted urine can be more reliably absorbed and retained, thereby preventing leakage.

[0175] In the above case, when the diaper 1 is in an unfolded and stretched state (Figure 9), it is preferable that a portion of the rear waist elastic member 43a is located at the end of the absorbent cores 21 to 24 in the width direction in the region of the rear end of the absorbent cores 21 to 24 in the longitudinal direction where the non-skinside layer 23 (first absorbent layer) is not present.

[0176] In this case, while the diaper 1 is being worn, the skin-side layer 21 and the intermediate layer 22 are pulled outward in the width direction by the rear waist elastic members 43a, thereby improving the flatness of the skin-side layer 21 and the intermediate layer 22. This ensures the absorption area of the two layers 21, 22, reduces the likelihood of gaps forming between the absorbent cores 21 and 24 and the wearer, and suppresses leakage of body waste. In this way, in areas where the absorbent cores 21-24 are thinner due to the absence of the non-skin-side layer 23, the skin-side layer 21 and the non-skin-side layer 22 can be pulled outward in the width direction efficiently by the waist elastic members 43. In other words, even if the contractile force of the waist elastic members 43 is small, the skin-side layer 21 and the non-skin-side layer 22 are easily pulled outward in the width direction.

[0177] However, the present invention is not limited to the above, and the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 may have the same longitudinal length, or the rear ends of the skin-side layer 21 and the intermediate layer 22 (first absorbent layer) may be located closer to the center than the rear end of the non-skin-side layer 23 (second absorbent layer). In this way, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 may be laminated over substantially the entire longitudinal area of the absorbent cores 21 to 24, or may be laminated only at certain positions in the longitudinal direction. Preferably, the three layers (21 to 23) are laminated at and near the position that comes into contact with the wearer's urinary excretion opening when the diaper 1 is worn.

[0178] Fig. 14 is a cross-sectional schematic diagram showing a modified example of the non-skin side layer 23. When the absorbent cores 21-24 have multiple absorbent layers, the multiple absorbent layers may have an SAP layer (here, the non-skin side layer 23) formed solely from SAP (super absorbent polymer). Furthermore, an SAP layer sheet in which an SAP layer is laminated on a base sheet such as a nonwoven fabric 26 may have a high basis weight region 233 in which the basis weight of the SAP is higher than that of the surrounding area. Note that the skin side layer 21 may be the SAP layer shown in Fig. 14 instead of the non-skin side layer 23.

[0179] In the high basis weight regions 233, points S where the thickness is greatest in the thickness direction are located intermittently in the longitudinal and width directions. As a result, the high basis weight regions 233 are arranged intermittently in the longitudinal and width directions. Furthermore, between adjacent points S where the thickness is greatest (i.e., around the high basis weight regions 233), low basis weight regions 234 where the SAP basis weight is lower than that of the high basis weight regions 233 are formed. However, as long as the points S where the thickness is greatest are located intermittently in the longitudinal and width directions, some of the spaces between adjacent points S where the thickness is greatest may be formed by the high basis weight regions 233. In other words, some of the spaces between adjacent points S where the thickness is greatest may be connected by the high basis weight regions 233.

[0180] The low basis weight region 234 has a low basis weight laminated region 234E where SAP is laminated, and a non-laminated region 234N where no SAP is present. Here, "no SAP" not only means that no SAP particles are present, but also includes a situation where there are only a small number of laminated SAP particles and there are essentially no SAP particles present.

[0181] In the non-skinside layer 23 of the modified example, the low-basis weight regions 234 (the low-basis weight laminated regions 234E and the non-laminated regions 234N) serve as folding points, allowing the diaper 23 to easily deform along the contours of the wearer's body, improving fit. This increases the flexibility of the absorbent body 20, reducing the torque value of the diaper 1 before absorption. Furthermore, the low-basis weight regions 234, which serve as folding points, include the low-basis weight laminated regions 234E, which can absorb and retain excrement, and the non-laminated regions 234N, which are more easily bent due to the absence of SAP. This allows the low-basis weight regions 234, which have a lower SAP basis weight than the high-basis weight regions 233, to both easily deform along the contours of the wearer's body and have sufficient absorption and retention capacity for excrement. In other words, the low-basis weight laminated regions 234E provide sufficient absorption and retention capacity, while the non-laminated regions 234N allow the SAP layer to bend more easily.

[0182] Furthermore, in the modified example shown in FIG. 14 , when the length in the thickness direction from the core wrap sheet 26 to the point S where the maximum thickness occurs is defined as the maximum thickness T, it is preferable that the maximum thickness T is 3 mm or less, and the distance D between adjacent points S where the maximum thickness occurs is 5 times or less than the maximum thickness T. With such a non-skin-side layer 23, it is possible to arrange a large number of high basis weight regions 233 and low basis weight regions 234 (compared to when the distance D between points S is more than 5 times the maximum thickness T) while maintaining the overall thinness of the absorbent body 20 (compared to when the maximum thickness T is greater than 3 mm). Therefore, the absorbent body 20 containing a superabsorbent polymer can maintain its thinness while improving its fit when worn. It is more preferable that the maximum thickness T is 2 mm or less, and the distance D between adjacent points S where the maximum thickness occurs is 4 times or less than the maximum thickness T. This allows the absorbent body 20 containing a superabsorbent polymer to maintain its thinness while improving its fit when worn. The maximum thickness T can be measured by the thickness measurement method described above (a method of cutting the absorber 20 and observing and measuring the cross section using an optical microscope). The distance D between the points S can also be measured by observing the cut surface using an optical microscope.

[0183] Furthermore, since the SAP layer does not contain liquid-absorbent fibers 201, the thickness of the absorbent body 20 can be reduced. In addition, in a plan view, the diameter of a circumscribing circle circumscribing each of the multiple high basis weight regions 233 is preferably 2 mm or more and 4 mm or less. This allows for the arrangement of a large number of high basis weight regions 233 and low basis weight regions 234, and improves the flexibility of the absorbent body 20. Furthermore, it is preferable that the low basis weight stacked regions 234E and the non-loading regions 234N are arranged intermittently in the longitudinal and width directions of the absorbent body 20. This allows the absorbent body 20 to easily deform along the irregularities of the wearer's body and to have the ability to absorb and retain excrement in a planar manner. 14 also has a channel region (for example, the low basis weight region 231 of the absorbent body 20 of FIG. 6) in which the basis weight of the superabsorbent polymer is lower than that of the high basis weight region 233, and the channel region extends in the longitudinal direction of the absorbent body 20, and the width of the channel region in the width direction is preferably greater than the distance D between adjacent points S of maximum thickness T. Furthermore, it is preferable that a plurality of the channel regions are provided in the width direction. This allows the channel regions to become folding start points, increasing the flexibility of the absorbent body 20.

[0184] The absorbent cores 21-24 have multiple absorbent layers stacked in the thickness direction (in the case of FIG. 4, the skin-side upper layer portion 24, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23). Preferably, one or more absorbent layers (21-23) located closer to the skin than the absorbent layer closest to the skin in the thickness direction (the skin-side upper layer portion 24) do not contain nonwoven fabric. Specifically, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 in this embodiment do not contain nonwoven fabric but are made of liquid-absorbent fiber 201 or SAP. This allows the number of stacked absorbent layers to be reduced and the thickness of each absorbent layer to be reduced while maintaining the absorption performance of the absorbent cores 21-24. This allows the torque value of the diaper 1 to be reduced before absorption.

[0185] Furthermore, it is preferable that the absorbent layer closest to the skin in the thickness direction (the skin-side upper layer portion 24 in FIG. 4) does not contain water-absorbent resin powder such as SAP. The skin-side upper layer 24 of this embodiment is formed only from liquid-absorbent fibers 201. This prevents the skin-side upper layer 24 from excessively swelling and inhibiting absorption of excrement. This allows the absorbent cores 21-24 to be effectively utilized in the thickness direction. This allows the number of absorbent layers to be reduced and the thickness of the absorbent layers to be reduced while maintaining absorption performance. This therefore allows the torque value of the diaper 1 before absorption to be reduced. In addition, this prevents the feel of the absorbent cores 21-24 from being reduced against the skin due to water-absorbent resin powder such as SAP (the occurrence of a gritty feeling).

[0186] Furthermore, it is preferable that the SAP (superabsorbent polymer) contained in the absorbent layer closest to the skin in the thickness direction has a liquid permeation rate under load of more than 10 seconds. Although not shown, the absorbent core may not have the skin-side upper layer 24. In such a case, the skin-side layer 21 in FIG. 4 corresponds to the absorbent layer closest to the skin. When the SAP contained in the skin-side layer 21 has a liquid permeation rate under load of more than 10 seconds, localized absorption of excreted fluid can be suppressed compared to when the SAP has a liquid permeation rate under load of 10 seconds or less, and the absorbent core can be used more effectively in the planar direction. Therefore, the number of absorbent layers can be reduced and the thickness of the absorbent layer can be reduced while maintaining absorption performance. Therefore, the torque value of the pants-type absorbent article before absorption can be reduced.

[0187] The liquid permeation rate under load of the highly absorbent polymer (water-absorbent resin, water-absorbent resin powder) of the skin side layer 21 can be measured by a known method, for example, the method described in JP-A-2019-41876. Specifically, 0.32±0.005 g of superabsorbent polymer was immersed in 100 mL of physiological saline (0.9% by mass sodium chloride solution) in a 100 mL glass beaker and left for 60 minutes. A separate cylindrical filtration tube was prepared, equipped with a wire mesh (150 μm mesh, Sansho Hanbai Biocolumn Sintered Stainless Steel Filter 30SUS) and a capillary tube (4 mm inner diameter, 8 cm length) with a stopcock (2 mm inner diameter) at the bottom of the opening of a vertically standing cylinder (25.4 mm inner diameter). With the stopcock closed, the entire contents of the beaker, including the swollen test sample, were poured into the cylindrical filtration tube. Next, a 2 mm diameter cylindrical rod with a 25 mm diameter wire mesh at its tip was inserted into the cylindrical filtration tube so that the wire mesh and the test sample were in contact with each other. A weight was then placed on the test sample to apply a 2.0 kPa load. After leaving the filter in this state for 1 minute, open the stopcock and allow the liquid to flow. Measure the time T1 (seconds) until the liquid level in the filtration cylinder reaches the 40 mL mark from the 60 mL mark (i.e., 20 mL of liquid passes through). Using the measured time T1 (seconds), calculate the liquid permeation rate under load at 2.0 kPa using the formula: Liquid permeation rate under load (seconds) = T1 - T0. Note that T0 (seconds) is the time required for 20 mL of saline to pass through the wire mesh without placing a sample in the filtration cylinder. Measurements are performed at a temperature of 23±2°C and a relative humidity of 50±5%, with the superabsorbent polymer held in the same environment for at least 24 hours before measurement.

[0188] ===Other=== The above-described 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.

[0189] The absorbent body 20 illustrated in Figure 4 is just one example, and the configuration of the absorbent body 20 is not particularly limited as long as the torque value of the diaper 1 before absorption in a torsion test is 23.4 mN m or less. For example, the absorbent core does not need to have multiple layers, and the volume ratio of SAP to liquid-absorbent fiber 201 in each of the multiple layers constituting the absorbent core may be different from that shown in Figure 4. Also, for example, the absorbent core may be composed of two layers, with the upper layer being composed of liquid-absorbent fiber 201 and SAP and having a substantially T-shaped planar shape, and the lower layer being a rectangular SAP sheet.

[0190] 4, the liquid-absorbent fiber 201 is arranged in the low basis weight region 221 of the intermediate layer 22, but the low basis weight region 221 of the intermediate layer 22 may be a slit. This allows excreted liquid to be quickly drawn deeper into the non-skin side layer 23.

[0191] Alternatively, the intermediate layer 22 and the non-skin side layer 23 may be laminated adjacent to each other in the thickness direction without the adhesive and / or nonwoven fabric 27. This prevents the adhesive and / or nonwoven fabric from interfering with the transfer of excreted fluid from the intermediate layer 22 to the non-skin side layer 23, and increases the rate of absorption by the non-skin side layer 23.

[0192] Alternatively, the intermediate layer 22 and the non-skinside layer 23 may be integrally formed. In this case, an adhesive or a nonwoven fabric may or may not be interposed between the intermediate layer 22 and the skinside layer 21. In this case, the skinside layer 21 may be an SAP layer composed only of SAP, or may be a layer composed of SAP and liquid-absorbent fibers 201. In this case, the average value of the total area occupied by SAP per unit area in a cross section taken along the thickness direction of the skinside layer 21 may be larger than the average value of the total area occupied by SAP per unit area in a cross section taken along the thickness direction of the non-skinside layer 23. This allows the SAP of the skinside layer 21 to suppress rewet.

[0193] Furthermore, the intermediate layer 22 need not necessarily be formed integrally with either the skin side layer 21 or the non-skin side layer 23, but may be formed integrally with both. Alternatively, the three layers 21 to 23 may be formed individually and then laminated. In this case, a nonwoven fabric or adhesive may or may not be provided between the skin side layer 21 and the intermediate layer 22, and between the intermediate layer 22 and the non-skin side layer 23. By using an adhesive or nonwoven fabric, excreted liquid can be more diffused in the planar direction on them. Without an adhesive or nonwoven fabric, the rate at which excreted liquid migrates to the non-skin side is increased.

[0194] In addition, it is preferable that an SAP layer that does not contain liquid-absorbent fibers 201 is present as the skin-side layer 21 or non-skin-side layer 23 in the absorbent cores 21-24. Liquid transfer is more likely to occur in an SAP layer than in a layer that contains liquid-absorbent fibers. When the non-skin-side layer 23 is an SAP layer, absorbency (water retention) is further improved. When the skin-side layer 21 is an SAP layer, rewet can be further suppressed. [Explanation of symbols]

[0195] 1. Pants-type absorbent article, 2 side joints, 3 Leakage prevention wall section, 10. Absorbent body; 12 Top sheet (surface sheet), 13 Back sheet (rear sheet), 14 exterior seats, 15 side seats, 16 Leak-proof wall elastic member, 17 Leg gather elastic member, 20 absorbent body, 201 liquid absorbent fiber, 21 Skin side layer (absorbent core), 211 low basis weight region, 212 constricted portion, 22 middle layer (absorbent core), 221 low basis weight region, 222 constricted portion, 23 Non-skin side layer (absorbent core), 231 Low basis weight region, 24 Upper layer (absorbent core) 25 Core wrap sheet (skin side core wrap sheet part), 26 Core wrap sheet (non-skin side core wrap sheet part), 27 nonwoven fabrics, 30 Front waistband, 31 skin side sheet, 32 non-skin side sheet, 33 waist elastic member (transverse elastic member), 34 cover sheets, 40 rear waistband, 41 skin side sheet, 42 non-skin side sheet, 43 waist elastic member (transverse elastic member), 44 cover sheets, 45 buttocks cover part, 451 buttocks side elastic member (transverse elastic member), 50 Point-shaped compressed part (compressed part) 60 jigs, 70 crotch area, 71 Inclined elastic member (transverse elastic member, leg gather elastic member), LG leg gathers, LG2 leg gathers, NEf non-stretchable region, NEb non-stretchable region, ER leg gathered elastic area, ERi inner leg gathered elastic area, ERo outer leg gathered elastic area,

Claims

1. The vertical direction, the width direction, and the front-rear direction are perpendicular to each other, A pants-type absorbent article having an absorbent core containing liquid-absorbent fibers and a superabsorbent polymer, In a torsion test in which the pant-type absorbent article is gripped at the center portions in the up-down direction at both end portions in the width direction and twisted around an imaginary axis along the width direction, and the pant-type absorbent article is gripped at the center portions in the width direction at both end portions in the up-down direction and twisted around an imaginary axis along the up-down direction, the torque value of the pant-type absorbent article before absorption is 23.4 mN m or less, A pants-type absorbent article, characterized in that there is no elastic member that continuously traverses the absorbent core in the width direction from one end to the other end in the width direction of the absorbent core.

2. The pants-type absorbent article according to claim 1, an absorbent body including the absorbent core and a transverse elastic member that stretches in the width direction, A pants-type absorbent article characterized in that the lateral elastic member continuously crosses the area of the absorbent main body where the absorbent core is not present from one end to the other end in the width direction.

3. The pants-type absorbent article according to claim 1 or 2, A transverse elastic member stretches in the width direction, A pants-type absorbent article, wherein a portion of the transverse elastic member is located at an end of the absorbent core in the width direction.

4. The pants-type absorbent article according to claim 1 or 2, A transverse elastic member stretches in the width direction, A pants-type absorbent article, wherein the transverse elastic members are positioned outside the outer periphery of the absorbent core.

5. The pants-type absorbent article according to claim 1 or 2, The absorbent garment has a front waistband, a rear waistband, transverse elastic members that stretch in the width direction, and an absorbent main body including the absorbent core, In the deployed and extended state, the front waistline portion and the rear waistline portion each have a non-stretchable region where the transverse elastic members are not located in a region overlapping the absorbent main body in the thickness direction; A pants-type absorbent article, characterized in that the widthwise length of the non-stretchable region of the front waistband portion is shorter than the widthwise length of the non-stretchable region of the rear waistband portion.

6. The pants-type absorbent article according to claim 1 or 2, a front waistband portion and a rear waistband portion joined by a pair of side joining portions; A pants-type absorbent article characterized in that, when at least one of the front waistband portion and the rear waistband portion is divided into four portions in the vertical direction, the contractile force of the lowest region is smaller than the contractile force of the second lowest region.

7. The pants-type absorbent article according to claim 1 or 2, A pair of leg gathers are provided along the legs of the wearer, The leg gather portion is provided with a leg gather elastic member along the stretch direction thereof, A pants-type absorbent article characterized in that the leg gather elastic members have an elongation ratio of 2.4 times or less.

8. The pants-type absorbent article according to claim 1 or 2, A pair of leg gathers are provided along the legs of the wearer, an absorbent body including the absorbent core, The absorbent main body has a pair of leakage prevention walls that can stand up on the skin side on both sides in the width direction, The leg gather portion is provided with a leg gather elastic member along the stretch direction thereof, The leak-preventing wall portion is provided with a leak-preventing wall elastic member that expands and contracts along the up-down direction, A pants-type absorbent article, characterized in that the contraction force of the leg gathered portions is smaller than the contraction force of the leakage barrier portions.

9. The pants-type absorbent article according to claim 1 or 2, A pair of leg gathers are provided along the legs of the wearer, The leg gather portion is provided with a plurality of leg gather elastic members along the stretch direction thereof, A pants-type absorbent article, characterized in that the contractile force of the leg gather elastic member provided on the innermost side is greater than the contractile force of the leg gather elastic member provided on the outermost side.

10. The pants-type absorbent article according to claim 1 or 2, A pair of leg gathers are provided along the legs of the wearer, The leg gather portion is provided with a plurality of leg gather elastic members along the stretch direction thereof, A pants-type absorbent article, wherein the contractile force of the leg gather elastic members provided on the innermost side is smaller than the contractile force of the leg gather elastic members provided on the outermost side.

11. The pants-type absorbent article according to claim 1 or 2, an absorbent body including the absorbent core, The absorbent main body has a pair of leg gather portions on both sides in the width direction, The leg gather portion is provided with a leg gather elastic member that stretches along the up-down direction, A pants-type absorbent article characterized in that, in an unfolded and stretched state, the leg gather elastic member is not provided in the innermost region when the region from the end of the absorbent core to the end of the absorbent main body in the width direction is divided into three.

12. The pants-type absorbent article according to claim 1 or 2, an absorbent body including the absorbent core, The absorbent main body has a pair of leg gather portions on both sides in the width direction, The leg gather portion is provided with three or more leg gather elastic members that stretch along the up-down direction, In the deployed and extended state, having a longitudinal direction perpendicular to the width direction, In the width direction, a region between the leg gather elastic member provided on the innermost side and the leg gather elastic member provided on the outermost side is defined as a leg gather elastic region, When the leg gather elastic region is divided into two equal parts in the width direction, the region located on the inner side is an inner leg gather elastic region, and the region located on the outer side is an outer leg gather elastic region, The average length of the leg gather elastic member disposed in the inner leg gather elastic region, to which an elastic force acts in the longitudinal direction, is A pants-type absorbent article characterized in that the length of the leg gather elastic member arranged in the outer leg gather elastic region is 10% or more shorter than the average length of the portion to which an elastic force is applied in the longitudinal direction.

13. The pants-type absorbent article according to claim 1 or 2, a skin-side core wrap sheet portion that covers at least a portion of the skin-side of the absorbent core; a non-skin-side core wrap sheet portion that covers at least a portion of the non-skin-side surface of the absorbent core; A surface sheet provided on the skin side of the skin side core wrap sheet portion; a back sheet provided on the non-skin side of the non-skin side core wrap sheet portion, A pants-type absorbent article having a portion where the top sheet and the back sheet are bonded together.

14. The pants-type absorbent article according to claim 1 or 2, The absorbent garment has a front waistband, a rear waistband, transverse elastic members that stretch in the width direction, and an absorbent main body including the absorbent core, The absorbent core has a low basis weight region having a basis weight lower than that of the surrounding area, In the deployed and extended state, the front waistline portion and the rear waistline portion each have a non-stretchable region where the transverse elastic members are not located in a region overlapping the absorbent main body in the thickness direction; A pants-type absorbent article characterized in that at least one of the non-elastic regions of the front waistband and the rear waistband overlaps with the low basis weight region in the width direction and extends outward in the width direction beyond the low basis weight region.

15. The pants-type absorbent article according to claim 1 or 2, An absorbent article characterized in that the absorbent core has a constricted portion constricted on the inside in the width direction in a crotch portion that is located between the legs of a wearer when worn.

16. The pants-type absorbent article according to claim 15, an absorbent body including the absorbent core, In the deployed and extended state, the front waistline portion and the rear waistline portion each have a non-stretchable region where the transverse elastic members are not located in a region overlapping the absorbent main body in the thickness direction; A pants-type absorbent article characterized in that the widthwise outer end of at least one of the non-elastic regions of the front waistband and the rear waistband is located widthwise outer than the narrowest point of the constricted portion, or is aligned with the widthwise position of the narrowest point.

17. The pants-type absorbent article according to claim 15, an absorbent body including the absorbent core, In the deployed and extended state, the front waistline portion and the rear waistline portion each have a non-stretchable region where the transverse elastic members are not located in a region overlapping the absorbent main body in the thickness direction; A pants-type absorbent article characterized in that the widthwise outer end of at least one of the non-elastic regions of the front waistband and the rear waistband is located widthwise more inward than the narrowest point of the constricted portion.

18. The pants-type absorbent article according to claim 1 or 2, A pants-type absorbent article, wherein the absorbent core has a plurality of compressed portions formed so as to partially compress the absorbent core in the thickness direction thereof.

19. The pants-type absorbent article according to claim 1 or 2, the absorbent core having a plurality of absorbent layers; the plurality of absorbent layers each having an SAP layer formed solely from the superabsorbent polymer; the SAP layer is laminated on a base sheet; In the deployed and extended state, having a longitudinal direction perpendicular to the width direction, the SAP layer sheet, in which the SAP layer is laminated on the base sheet, has a high basis weight region having a basis weight higher than that of the surrounding area; the high basis weight regions are arranged such that points of maximum thickness are located intermittently in the longitudinal direction and the width direction, A pants-type absorbent article characterized in that the maximum thickness is 3 mm or less, and the distance between adjacent points of the maximum thickness is 5 times or less the maximum thickness.

20. The pants-type absorbent article according to claim 1 or 2, The absorbent core has a plurality of absorbent layers stacked in the thickness direction thereof, the plurality of absorbent layers includes a first absorbent layer and a second absorbent layer; In the deployed and extended state, having a longitudinal direction perpendicular to the width direction, A pants-type absorbent article, characterized in that, in the longitudinal direction, the rear end of the first absorbent layer is located closer to the center than the rear end of the second absorbent layer.

21. 21. The pants-type absorbent article according to claim 20, A transverse elastic member stretches in the width direction, A pants-type absorbent article characterized in that, in an unfolded and stretched state, at the rear end of the absorbent core in the longitudinal direction, in a region where the first absorbent layer is not present, a portion of the transverse elastic member is located at the end of the absorbent core in the width direction.

22. The pants-type absorbent article according to claim 1 or 2, The absorbent core comprises: a skin-side layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the liquid-absorbent fiber; an intermediate layer in which the volume occupied by the liquid-absorbent fibers is greater than the volume occupied by the superabsorbent polymer; a non-skin side layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the liquid-absorbent fiber, the intermediate layer is located closer to the skin than the skin side layer in the thickness direction, The pants-type absorbent article is characterized in that the non-skin-side layer is located closer to the skin than the intermediate layer in the thickness direction.

23. The pants-type absorbent article according to claim 1 or 2, The absorbent core has a plurality of absorbent layers stacked in the thickness direction thereof, A pants-type absorbent article, characterized in that one or more of the absorbent layers located closer to the skin than the absorbent layer located closest to the skin in the thickness direction do not contain nonwoven fabric.

24. 24. The pant-type absorbent article according to claim 23, A pants-type absorbent article, wherein the absorbent layer located closest to the skin in the thickness direction does not contain water-absorbent resin powder.

25. 24. The pant-type absorbent article according to claim 23, A pants-type absorbent article, characterized in that the superabsorbent polymer contained in the absorbent layer located closest to the skin in the thickness direction has a liquid permeation rate under load of more than 10 seconds.

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