Absorbent article

Abstract

To reduce the possibility that an absorbent article after absorbing excreta becomes conspicuous from outside clothing, make it easier to fit the absorbent article to the wearer's body and alleviate discomfort during wearing.SOLUTION: An absorbent article (1), in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction orthogonal to each other, and includes an absorbent core (20A). The absorbent core (20A) comprises cellulose fibers and a highly absorbent polymer, and the absorbent core includes low basis weight parts (211, 221, 231) having a lower basis weight than surrounding portions and extending along the longitudinal direction. In a two-folded state of the absorbent article, after placing a weight of 5 kg with a bottom area of 150 cm2 on the absorbent article for 24 hours and then removing the weight, a central thickness in the width direction at the folded part of the absorbent article is 6.5 mm or less, a central thickness in the width direction at the folded part of the absorbent article in an absorbed state is 20.3 mm or less, and a torque value of the absorbent article in a torsion test is 44.1 mN m or less.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an absorbent article. [Background technology]

[0002] Conventionally, there are absorbent articles such as disposable diapers that include a liquid-absorbing absorbent body. When worn, it is preferable that the absorbent article is not noticeable from the outside of clothing. Generally, among absorbent articles, the absorbent body (absorbent core) that absorbs bodily waste is particularly thick and rigid. It is known that the absorbent body is made of a superabsorbent polymer, a liquid-absorbent fiber, or the like. For example, Patent Document 1 discloses an absorbent article that includes an absorbent body in which a superabsorbent polymer is arranged in the form of a sheet. A superabsorbent polymer has the characteristics of high liquid retention and allowing the absorbent body to be formed thinly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-122342 Summary of the Invention [Problem to be solved by the invention]

[0004] When absorbent articles equipped with an absorbent body (SAP sheet) made of superabsorbent polymer are first worn before absorbing bodily waste (liquid), the absorbent body is thin, making the absorbent article less noticeable from the outside of clothing, but once bodily waste is absorbed, the superabsorbent polymer swells, increasing the rigidity of the absorbent body, making the absorbent article thicker and making the absorbent article more noticeable from the outside of clothing, as well as increasing the rigidity of the absorbent body, making the wearer more likely to feel uncomfortable. On the other hand, while providing the absorbent body with liquid-absorbent fibers prevents excessive swelling of the absorbent body (superabsorbent polymer) due to absorption of bodily waste and prevents the absorbent body's rigidity from becoming excessively high, the absorbent body (absorbent article) becomes thicker before absorbing bodily waste, which creates the problem of the absorbent article being more noticeable from the outside of clothing.

[0005] The present invention has been made in consideration of the above-mentioned conventional problems, and its purpose is to provide an absorbent article that reduces the risk of the absorbent article being noticeable from the outside of clothing after absorbing excrement, that is easy to fit to the wearer's body, and that is easy to reduce discomfort when worn. [Means for solving the problem]

[0006] The main invention for achieving the above object is an absorbent article having a longitudinal direction, a width direction, and a thickness direction which are perpendicular to one another in an unfolded state, and comprising an absorbent core, wherein the absorbent core comprises cellulose fibers and a superabsorbent polymer, the absorbent core has a basis weight lower than that of its surroundings and comprises a low basis weight portion along the longitudinal direction, and when the absorbent article is folded in half at a fold in the center of the longitudinal direction, a weight having a base area of 150 cm2 and weighing 5 kg is placed on the absorbent article for 24 hours, and after the weight is removed, the absorbent article has a thickness of 6.5 mm or less at the center of the width direction of the folded portion, and when the weight is removed, the thickness of the longitudinal direction is 6.5 mm or less at the center of the width direction of the folded portion, and when the weight is removed, the thickness of the longitudinal direction is 6.5 mm or less at the skin side of the absorbent article in the unfolded and stretched state. and a torsion test in which the absorbent article is folded in half at the center in the width direction and the center in the width direction is gripped and twisted around the imaginary axis along the width direction, and a torque value of the absorbent article is 44.1 mN m or less. 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, the risk of the absorbent article being noticeable from the outside of clothing after absorbing excrement can be reduced, and the absorbent article can be made to fit the wearer's body easily and reduce discomfort when worn. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a diaper 1. [Figure 2] 1 is a plan view of the 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] 1 is a diagram illustrating a state in which a weight W is placed on the diaper 1. FIG. [Figure 9] FIG. 10 is a diagram illustrating the process for achieving an absorbing state. [Figure 10] FIG. 10 is a diagram illustrating the measurement of the folded portion F. [Figure 11] FIG. 1 is an explanatory diagram of a "torsion test." [Figure 12] FIG. 1 is a diagram showing measurement results of diaper 1 and products A, B, and C. [Figure 13] 10 is a cross-sectional view of an absorbent body 20 showing a modified example of the skin side layer 21. FIG. [Figure 14] 10 is a cross-sectional view of a modified example of the absorbent body 20. 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) An absorbent article having an absorbent core in an unfolded state, which has a longitudinal direction, a width direction, and a thickness direction that are perpendicular to one another, the absorbent core comprising cellulose fibers and a superabsorbent polymer, the absorbent core having a basis weight lower than that of its periphery and comprising a low basis weight portion along the longitudinal direction, and having a base area of 150 cm when the absorbent article is folded in half at a fold in the center in the longitudinal direction. 2A weight having a weight of 5 kg is placed on the absorbent article for 24 hours, and then the weight is removed from the absorbent article, and the thickness of the folded portion at the center in the width direction is 6.5 mm or less. 40 ml of artificial urine is dropped three times over 5 seconds onto the skin side of the absorbent article in the unfolded and stretched state after the weight is removed, at a position 50 mm forward from the center in the longitudinal direction and at the center in the width direction. In this case, the absorbent article has a thickness of 6.5 mm or less at the center in the width direction. The absorbent article is characterized in that the thickness of the folded portion at the center in the width direction is 20.3 mm or less, and in a torsion test in which the center in the longitudinal direction of both end portions in the width direction of the absorbent article in the folded state is grasped and twisted around an imaginary axis along the width direction, and the center in the width direction of both end portions in the longitudinal direction of the absorbent article in the folded state is grasped and twisted around an imaginary axis along the longitudinal direction, the torque value of the absorbent article is 44.1 mN·m or less.

[0010] According to the first aspect, even if the thickness of the folded portion in the folded state when the weight is removed is 6.5 mm or less, the absorbent article includes cellulose fibers with a relatively high absorption rate, a superabsorbent polymer with a relatively high liquid retention, and a low basis weight portion along the longitudinal direction, which facilitates increased diffusion of body exudates along the longitudinal direction and reduces the risk of localized absorption of body exudates. Furthermore, by setting the thickness of the folded portion in the absorbed state to 20.3 mm or less, the risk of the absorbent article becoming excessively thick due to the absorption of body exudates during wear is reduced compared to when the thickness in the absorbed state is greater than 20.3 mm, thereby reducing the risk of the absorbent article being noticeable from the outside of clothing after absorption. Furthermore, by setting the torsion test value of the absorbent article in the absorbed state to 44.1 mN·m or less, even after absorption of body exudates, the absorbent article can be made softer than when the torsion test value is greater than 44.1 mN·m, which allows the absorbent article to fit the wearer's body more easily even after absorption of body exudates and reduces discomfort when worn.

[0011] (Aspect 2) In the absorbent article of aspect 1, the absorbent core has a constricted portion constricted on the inside in the width direction in the crotch portion that is located between the crotch of a wearer when worn.

[0012] According to aspect 2, when worn, the absorbent article can be made to fit the shape of the wearer's body more easily, and even if the absorbent core expands to absorb excrement, the risk of it interfering with the movement of the wearer's legs can be reduced.

[0013] (Aspect 3) The absorbent article of aspect 1 or 2 is characterized in that the liquid absorption rate of the superabsorbent polymer measured by the vortex method is 40 seconds or more.

[0014] According to the third aspect, when excrement is absorbed in the absorbent core, the excrement is more likely to diffuse within the absorbent core than if it were absorbed by the superabsorbent polymer when the liquid absorption rate of the superabsorbent polymer by the vortex method was faster than 40 seconds. This allows the superabsorbent polymer to locally absorb the excrement, reducing the risk of the absorbent core swelling locally, thereby reducing the risk of the absorbent article becoming excessively stiff and making it easier to soften the absorbent article after absorption. This reduces the risk of the absorbent article being noticeable from the outside of clothing even after absorbing excrement, and makes it less likely to hinder the wearer's leg movement.

[0015] (Aspect 4) The absorbent article of any one of Aspects 1 to 3 is characterized in that the core wrap sheet provided on at least one of the skin side and non-skin side of the absorbent core is a hydrophilic nonwoven fabric.

[0016] According to aspect 4, the hydrophilic nonwoven fabric is thin and flexible, and has high drapeability after absorbing bodily waste. Therefore, when the absorbent article is worn, it easily fits the shape and movements of the wearer's body while maintaining a state in which it covers the absorbent core, thereby reducing the risk of the absorbent article being noticeable from the outside of the clothing.

[0017] (Aspect 5) The absorbent core has a skin-side core wrap sheet portion that covers at least a part of the skin-side side of the absorbent core, and the cellulose fibers and the superabsorbent polymer are bonded to the non-skin side of the skin-side core wrap sheet portion, and the basis weight of the cellulose fibers bonded to the skin-side core wrap sheet portion is 5 g / m 2 More than 90g / m 2 the basis weight of the superabsorbent polymer bonded to the skin-side core wrap sheet portion is 5 g / m or less; 2 More than 160g / m 2 The absorbent article of any one of Aspects 1 to 4 is characterized in that:

[0018] According to aspect 5, the absorbent article has the function of absorbing bodily waste, while the thickness of the absorbent core can be reduced, thereby reducing the thickness of the absorbent article and reducing the risk of the absorbent article being noticeable from the outside of clothing while being worn. In addition, the absorbent article can be made soft, making it easier to fit the wearer's body and movements, and reducing the discomfort felt by the wearer.

[0019] (Aspect 6) An absorbent article according to any one of aspects 1 to 5, comprising a skin-side core wrap sheet portion covering at least a portion of the skin-facing side of the absorbent core, and a non-skin-side core wrap sheet portion covering at least a portion of the non-skin-facing side of the absorbent core, wherein the cellulose fibers and the superabsorbent polymer are adhered to the non-skin-side of the skin-side core wrap sheet portion, the cellulose fibers and the superabsorbent polymer are adhered to the skin-side of the non-skin-side core wrap sheet portion, the cellulose fibers not adhered to either the skin-side core wrap sheet portion or the non-skin-side core wrap sheet portion account for 5% or less by weight of the cellulose fibers, the density of the cellulose fibers adhered to the non-skin-side of the skin-side core wrap sheet portion is uniform, and the density of the superabsorbent polymer adhered to the non-skin-side of the skin-side core wrap sheet portion is uniform.

[0020] According to aspect 6, the cellulose fibers bonded to the skin-side core wrap sheet portion and the non-skin-side core wrap sheet portion, and the cellulose fibers and superabsorbent polymer bonded to the skin-side core wrap sheet portion at uniform densities, allow the thickness of the absorbent body and the absorbent article to be reduced, reducing the risk of the absorbent article being noticeable from the outside of clothing while being worn.In addition, while maintaining the function of absorbing excrement as an absorbent article, it is easy to fit to the wearer's body and movements, reducing the discomfort felt by the wearer.

[0021] (Aspect 7) The absorbent article of any one of aspects 1 to 6, wherein the absorbent core has a plurality of absorbent layers, the plurality of absorbent layers having a first absorbent layer and a second absorbent layer, the low basis weight portion having a first low basis weight portion provided in the first absorbent layer and a second low basis weight portion provided in the second absorbent layer, and having a portion where the first low basis weight portion and the second low basis weight portion overlap when viewed in the thickness direction.

[0022] According to aspect 7, the absorption function of the absorbent article is ensured by multiple absorbent layers, and the diffusion of excrement in the absorbent core can be improved by the first low basis weight section and the second low basis weight section, which have overlapping portions in the thickness direction, thereby reducing the risk of the absorbent article becoming thick in certain areas.

[0023] (Aspect 8) The absorbent article of any one of aspects 1 to 7 is characterized in that the absorbent core has a plurality of absorbent layers, each of which has an SAP layer formed only from the superabsorbent polymer, the SAP layer being located furthest away from the skin among the plurality of absorbent layers, and an intermediate sheet being provided between the SAP layer and the absorbent layer located closer to the skin than the SAP layer.

[0024] According to the eighth aspect, the inclusion of the SAP layer allows the absorbent article to be thin, while still retaining the appropriate function of absorbing bodily waste as an absorbent article.

[0025] (Aspect 9) An absorbent article according to any one of aspects 1 to 8, characterized in that the absorbent core has a plurality of absorbent layers, the plurality of absorbent layers having a first absorbent layer and a second absorbent layer, and on one side in the width direction, the side ends of the first absorbent layer and the second absorbent layer are located at different positions.

[0026] According to the ninth aspect, it becomes easier to reduce the torsional rigidity of the side end portions of the absorbent article, which makes it easier to reduce discomfort around the legs of the wearer and to reduce the risk of impeding leg movement.

[0027] (Aspect 10) An absorbent article according to any one of aspects 1 to 9, characterized in that the absorbent core has a plurality of absorbent layers, the plurality of absorbent layers having a first absorbent layer and a second absorbent layer, and one end of the first absorbent layer in the longitudinal direction and one end of the second absorbent layer in the longitudinal direction are located at different positions.

[0028] According to aspect 10, it is possible to reduce the torsional rigidity of one end of the absorbent core in the longitudinal direction while reducing the thickness of one end of the absorbent core in the absorbent article, which makes it easier to reduce the risk of the absorbent article being noticeable from the outside of clothing.

[0029] (Aspect 11) The absorbent core has a skin-side layer having a first thickness and in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers, an intermediate layer having a second thickness and in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer, and a non-skin-side layer having a third thickness and in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers, wherein 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.

[0030] According to aspect 11, the absorbent core has the desired absorption function and flexibility, while reducing the risk of the absorbent core becoming excessively thick, making it easier to fit the wearer's body and movements, and reducing the risk of the absorbent article being noticeable from the outside of the clothing even after absorbing excrement.

[0031] (Aspect 12) The absorbent article of aspect 12 is characterized in that the superabsorbent polymer contained in the skin-side layer has a slower liquid absorption rate as measured by the vortex method than the superabsorbent polymer contained in the non-skin-side layer.

[0032] According to the twelfth aspect, diffusion in the planar direction or toward the non-skin side is more easily promoted than absorption in the skin-side layer, and bodily excrement is more easily diffused in the absorbent core 20A, thereby reducing the risk of localized swelling of the absorbent core, thereby reducing the torsional rigidity of the absorbent article, making it easier to fit the wearer's body when worn, and reducing discomfort when worn. In addition, the risk of the absorbent article being noticeable from the outside of clothing after absorption can be reduced.

[0033] (Aspect 13) An absorbent article according to aspect 11 or 12, characterized in that the average value of the total area occupied by the superabsorbent polymer per unit area in a cross section along the thickness direction of the skin-side layer is greater than the average value of the total area occupied by the superabsorbent polymer per unit area in a cross section along the thickness direction of the non-skin-side layer.

[0034] According to the thirteenth aspect, the non-skin-side layer of the absorbent core is more likely to retain excrement than the skin-side layer, reducing the risk of localized swelling of the absorbent core and lowering the torsional rigidity of the absorbent article, which makes it easier to fit the wearer's body and reduces discomfort when worn. It also reduces the risk that the absorbent article will be noticeable from the outside of clothing after absorption.

[0035] (Aspect 14) An absorbent article according to any one of aspects 11 to 13, characterized in that the total water retention capacity of the superabsorbent polymer present in the skin-side layer is less than the total water retention capacity of the superabsorbent polymer present in the non-skin-side layer.

[0036] According to the fourteenth aspect, since the non-skin-side layer of the absorbent core is more likely to retain excrement than the skin-side layer, the risk of localized swelling of the absorbent core can be reduced, which in turn reduces the torsional rigidity of the absorbent article, making it easier for the absorbent article to fit the wearer's body when worn, and reducing discomfort when worn. In addition, the risk of the absorbent article being noticeable from the outside of clothing after absorption can be reduced.

[0037] (Aspect 15) An absorbent article according to any one of aspects 1 to 14, characterized in that it has a skin-side core wrap sheet portion that covers at least a portion of the skin-facing side of the absorbent core, a non-skin-side core wrap sheet portion that covers at least a portion of the non-skin-facing 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.

[0038] According to the fifteenth aspect, the number of overlapping members in the thickness direction can be reduced compared to when the topsheet is folded up to the non-skin side of the non-skin side core wrap sheet portion or when the backsheet is folded up to the skin side of the skin side core wrap sheet portion, which makes it easier to reduce the torsional rigidity of the absorbent article, makes it easier to fit the wearer's body when worn, and reduces discomfort when worn. Also, it is possible to reduce the risk of the absorbent article being noticeable from the outside of clothing.

[0039] (Aspect 16) The density of the absorbent core is 0.2 g / cm 3 The absorbent article according to any one of aspects 1 to 15 is characterized by the above.

[0040] According to a sixteenth aspect, the density of the absorbent core is 0.2 g / cm 3Since the absorbent core is likely to diffuse excrement more readily than if it were smaller, the risk of localized swelling of the absorbent core can be reduced, which in turn reduces the torsional rigidity of the absorbent article, making it easier to fit the wearer's body when worn and reducing discomfort when worn. In addition, the risk of the absorbent article being noticeable from the outside of clothing after absorption can be reduced.

[0041] (Aspect 17) An absorbent article according to any one of aspects 1 to 16, characterized in that it has a skin-side core wrap sheet portion that covers at least a portion of the skin-facing side of the absorbent core, and a top sheet that is provided on the skin side of the skin-side core wrap sheet portion, and the density of the absorbent core is higher than the density of the top sheet.

[0042] According to the seventeenth aspect, the absorbent core is less likely to expand after absorbing bodily waste than when the density of the absorbent core is lower than that of the topsheet, which reduces the torsional rigidity of the absorbent article, making it easier to fit the wearer's body when worn and reducing discomfort when worn. It also reduces the risk that the absorbent article will be noticeable from the outside of clothing after absorption.

[0043] (Aspect 18) An absorbent article according to any one of aspects 11 to 17, characterized in that the absorbent core has a plurality of absorbent layers including the skin-side layer, the intermediate layer, and the non-skin-side layer, and among the plurality of absorbent layers, one or more absorbent layers located non-skin-side relative to the absorbent layer located closest to the skin in the thickness direction do not contain nonwoven fabric.

[0044] According to aspect 18, the risk of the absorbent article becoming excessively thick due to the absorption of bodily excrement is reduced, and the risk of the absorbent article being noticeable from the outside of clothing after absorption is reduced, while the absorbent article can be softened even after absorbing bodily excrement, making it easier to fit the wearer's body and reducing discomfort when worn.

[0045] (Aspect 19) An absorbent article according to any one of aspects 11 to 18, characterized in that the absorbent core has a plurality of absorbent layers including the skin-side layer, the intermediate layer, and the non-skin-side layer, and among the plurality of absorbent layers, the absorbent layer located closest to the skin in the thickness direction does not contain absorbent resin powder.

[0046] According to aspect 19, the risk of the absorbent article increasing locally in thickness due to the absorption of bodily excrement is reduced, and the risk of the absorbent article becoming noticeable from the outside of clothing after absorption is reduced, while the absorbent article can be softened even after absorbing bodily excrement, making it easier to fit the wearer's body and reducing discomfort when worn.

[0047] (Aspect 20) An absorbent article according to any one of aspects 11 to 18, characterized in that the absorbent core has a plurality of absorbent layers including the skin-side layer, the intermediate layer, and the non-skin-side layer, and among the plurality of absorbent layers, the absorbent layer located closest to the skin in the thickness direction comprises the superabsorbent polymer, and the liquid permeation rate under load of the superabsorbent polymer of the absorbent layer located closest to the skin exceeds 10 seconds.

[0048] According to aspect 20, the risk of the absorbent article increasing locally in thickness due to the absorption of bodily excrement is reduced, and the risk of the absorbent article being noticeable from the outside of clothing after absorption is reduced, while the absorbent article can be softened even after absorbing bodily excrement, making it easier to fit the wearer's body and reducing discomfort when worn.

[0049] === Implementation form === The absorbent article according to the present invention will be described taking as an example a pants-type disposable diaper 1 for infants (hereinafter also referred to as "diaper 1"). However, the absorbent article according to the present invention also includes tape-type disposable diapers, shorts-type napkins, absorbent pads, sanitary napkins, and other absorbent articles. Furthermore, the wearer of the absorbent article is not limited to infants, but may also be an adult or a living organism such as an animal.

[0050] <Diaper 1 composition> FIG. 1 is a schematic perspective view of a diaper 1. FIG. 2 is a 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 pair of side joining sections 2 provided on both sides of the diaper 1 are separated, and the diaper 1 is opened and unfolded in a flat plane.

[0051] The diaper 1 has a vertical direction, a width direction, and a front-to-rear direction that are perpendicular to each other, 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 abdominal side, and the rear side corresponds to the wearer's dorsal side. The width direction is the direction along the stretch direction of the elastic threads 33, 43 of the front waist portion 30 and the rear waist portion 40, and is also referred to as the left-to-right direction. The vertical direction is the direction along the orthogonal direction that is perpendicular to the stretch direction.

[0052] The diaper 1 is a so-called three-piece pants-type diaper having a liquid-absorbent main body 10 and a pair of waist-surrounding sections 30, 40. Of the pair of waist-surrounding sections, the one covering the wearer's abdominal region is also referred to as the front waist-surrounding section 30, and the one covering the wearer's dorsal region is also referred to as the rear waist-surrounding section 40.

[0053] 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. Line CC in Fig. 2 etc. is the centerline in the width direction, and line CL is the centerline in the longitudinal direction. The thickness direction, as shown in Fig. 3, is the direction in which the materials constituting the diaper 1 are layered. 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, and each longitudinal end of the absorbent main body 10 is joined and fixed to the skin side of the nearest waistband 30, 40, resulting in a generally H-shaped appearance in a plan view. Then, from this state, the absorbent main body 10 is folded in half at a folding portion F on the center line CL in the longitudinal direction. In this folded state (hereinafter also referred to as the "folded in half state"), the front waistline portion 30 and the rear waistline portion 40, which face each other, are joined and connected at their sides on both sides in the width direction to form a pair of side joining portions 2. The side joining portions 2 are formed by known joining means such as welding or adhesion.

[0054] The absorbent main body 10 has an absorbent body 20 (details will be described later), a liquid-permeable top sheet (surface sheet) 12 arranged closer to the skin than the absorbent body 20, and a back sheet (back surface sheet) 13 arranged closer to the skin than the absorbent body 20. The back sheet 13 has a two-layer structure consisting of a liquid-impermeable sheet 13a and a hydrophobic exterior sheet 13b arranged on the far side of the liquid-impermeable sheet 13a. However, the absorbent main body 10 may also include sheet members other than these. For example, a second sheet (not shown) may be provided between the top sheet 12 and the absorbent body 20 in the thickness direction.

[0055] The absorbent main body 10 is provided with a pair of leakage barrier walls 3 on both sides in the width direction along the longitudinal direction of the absorbent main body 10. In FIG. 3, a leakage barrier elastic member 16, such as rubber thread, is attached between the folded side sheets 15 in a stretched state along the longitudinal direction of the absorbent main body 10. This allows the leakage barrier walls 3 to stand up toward the skin side. However, this is not limited to the above. The pair of leakage barrier walls may be formed by folding a portion of the outer sheet 13b toward the skin side at multiple locations while extending outward beyond both ends of the absorber 20, or the diaper 1 may not have the leakage barrier walls 3. The absorbent main body 10 also has a pair of leg gathers LG on both sides in the width direction. The leg gathers LG are provided with a plurality of leg gather elastic members 17, such as rubber thread, that stretch along the longitudinal direction (up-down direction). In FIG. 3, the end of the outer sheet 13b extending outward in the width direction from the absorbent main body 10 is folded back onto the liquid-impermeable sheet 13a. Between the folded-back portions of the exterior sheet 13b, leg gather elastic members are attached in a stretched state along the longitudinal direction.

[0056] The front waistline section 30 and the rear waistline section 40 each have a skin-side sheet 31, 41, a non-skin-side sheet 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 sheet 31, 41 and the non-skin-side sheet 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 section 30 and the rear waistline section 40 to fit the wearer's waist. In addition, cover sheets 34, 44 may be provided 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.

[0057] 2, the front waistline portion 30 and the rear waistline portion 40 have different planar shapes in the unfolded and stretched state. The front waistline portion 30 has a vertical length that is roughly the same as that of the side joint portion 2 and a rectangular shape that is long in the width direction. The rear waistline portion 40 has a rectangular portion that overlaps with the front waistline portion 30 and a generally trapezoidal portion 40E that extends downward from the rectangular portion 30. The extending portion 40E can cover the wearer's buttocks.

[0058] 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.

[0059] ===About absorbent body 20=== Fig. 4 is a cross-sectional schematic diagram of the absorbent body 20 of this embodiment. Fig. 4 is a diagram illustrating a cross section at the center CL in the longitudinal direction of the absorbent body 20. 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.

[0060] As shown in FIG. 4, the absorbent body 20 has an absorbent core 20A between a skin-side core wrap sheet (skin-side core wrap sheet portion) 25 and a non-skin-side core wrap sheet (non-skin-side core wrap sheet portion) .

[0061] The absorbent core 20A includes 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 are usable as absorbent cores for absorbent articles. For example, the liquid-absorbent fiber 201 may be a fiber containing cellulose fiber, such as 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. The liquid-absorbent fiber 201 of this embodiment is formed from 100% cellulose fiber made from wood pulp fiber. Examples of SAP include starch-based, cellulose-based, and synthetic polymer-based polymer absorbents. The absorbent core 20A includes an absorbent core 21, an absorbent core 22, and an absorbent core 23.

[0062] The core wrap sheets 25, 26 are liquid-permeable sheet materials, such as tissue or nonwoven fabric. However, it is preferable that at least one of the core wrap sheets 25, 26 is a hydrophilic nonwoven fabric. A hydrophilic nonwoven fabric is a thin and flexible material that exhibits high drapeability after absorbing excrement (liquid). Therefore, when the diaper 1 is worn, it flexibly moves and conforms to the wearer's body movements and shape while maintaining a state in which it covers the skin side or non-skin side of the absorbent core 20A, making it easier to fit. This also helps reduce the risk of the diaper 1 being noticeable from the outside of clothing even after absorbing excrement.

[0063] The absorbent core 20A has a skin-side layer (absorbent core) 21, an intermediate layer (absorbent core) 22, and a non-skin-side layer (absorbent core) 23. The intermediate layer 22 is located closer to the skin in the thickness direction than the skin-side layer 21, and the non-skin-side layer 23 is located closer to the skin in the thickness direction than the intermediate layer 22. The skin-side layer 21 has a first thickness t1, and is a layer in which the volume occupied by SAP 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 (pulp layer) in which the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by the SAP. The non-skin-side layer 23 has a third thickness t3, and is a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fibers 201.

[0064] Furthermore, the absorbent core 20A of the absorbent body 20 of this embodiment is further provided with a skin-side upper layer (absorbent core) 24 on the skin side of the skin-side layer 21 in the thickness direction, the skin-side upper layer 24 having 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 larger 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.

[0065] 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.

[0066] 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.

[0067] 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 a nonwoven fabric 27 (hereinafter also referred to as "intermediate sheet 27"). The presence of the nonwoven fabric 27 allows excreted liquid to diffuse in the planar direction on the nonwoven fabric 27 before transferring from the intermediate layer 22 to the non-skin side layer 23. Therefore, the excreted liquid diffused in the planar direction can transfer to the non-skin side layer 23, allowing the absorbent core 20A to be effectively utilized in the planar direction.

[0068] The skin side layer 21 and intermediate layer 22 illustrated in Fig. 6A are integrally formed and have the same planar shape. The skin side layer 21 and intermediate layer 22 have constricted portions 212, 222 constricted inward in the width direction at the center in the longitudinal direction (Fig. 5). Note that the skin side layer 21 and intermediate layer 22 are divided into thirds at their maximum longitudinal length, and the center region is defined as the center in the longitudinal direction, where at least a part of the constricted portions 212, 222 may be located.

[0069] 6B has three longitudinally elongated rectangular divided regions 23a-23c. The three divided regions 23a-23c are arranged side by side at intervals in the width direction. Two regions between the three divided regions 23a-23c form low basis weight regions 231 (slits) of the non-skin side layer 23. The two low basis weight regions 231 are arranged symmetrically in the width direction across the center line C-C of the non-skin side layer 23.

[0070] FIG. 7 is a schematic plan view of the absorbent body 20 as viewed from the skin side. As shown in FIG. 7, in this embodiment, the skin side layer 21 has a plurality of compressed dots 50 formed by compressing the skin side layer 21 (absorbent core 21) in a dotted pattern in the thickness direction. The "compressed dots 50" are portions of the absorbent core 21 that have been compressed in the thickness direction by embossing. The compression increases the fiber density of the absorbent core 21 compared to uncompressed portions. In this embodiment, the compressed dots 50 are formed as a collection of dots (circles), but the compressed dots 50 may also be formed in a line (straight line, curved line), for example. Alternatively, the compressed dots or lines may be formed discretely within a predetermined region. As shown in FIG. 7, the compressed dots 50 are arranged in a dotted grid pattern (a so-called quilting pattern) as a whole, but other patterns may also be used. These compressed dots 50 reduce clumps of SAP during compression, suppressing the gritty feel of SAP. Furthermore, localized compression prevents collapse of the absorbent body 20 without impairing the flexibility of the absorbent cores 21-24. The compressed dots 50 may be provided not only in the skin-side layer 21 but also in the intermediate layer 22 and non-skin-side layer 23.

[0071] The diaper 1 has an absorbent core 20A containing cellulose fibers and a superabsorbent polymer, and includes low basis weight regions (low basis weight portions) 211, 221, and 231. The low basis weight regions (low basis weight portions) 211, 221, and 231 are portions that have a lower basis weight than the surrounding areas and are aligned along the longitudinal direction. When the diaper 1 is folded in half at a fold F at the center CL in the longitudinal direction, the bottom area is 150 cm. 2After placing a 5 kg weight on the diaper 1 for 24 hours, the thickness of the diaper 1 at the center (C-C) in the width direction of the folded portion F is 6.5 mm or less when the weight is removed. Furthermore, 40 ml of artificial urine is dripped three times over 5 seconds onto the skin-facing side of the diaper 1 in an unfolded and stretched state without the weight, at a position 50 mm forward from the center CL in the longitudinal direction and at the center CC in the width direction (the "drop position Pt" described below), to bring the diaper 1 into an absorbed state in which the artificial urine has been absorbed. In this absorbed state, the thickness of the center CC in the width direction of the folded portion F of the diaper 1 is 20.3 mm or less. Furthermore, in a torsion test in which the folded diaper 1 is gripped at the longitudinal center of both widthwise ends and twisted around an imaginary axis along the width direction, and also gripped at the longitudinal center of both widthwise ends and twisted around an imaginary axis along the lengthwise direction, the torque value of the diaper 1 is 44.1 mN m or less. The state in which the weight is placed and each measurement method will be described later.

[0072] The absorber 20 (absorbent core 20A) is a component in the diaper 1 that absorbs excrement such as urine and retains the absorbed excrement. Therefore, the absorber 20 is required to have a desired absorption function, while also being a component in the diaper 1 that has high rigidity.

[0073] In absorbent articles such as disposable diapers, the absorbent body (absorbent core) is a particularly thick portion. It has been known that superabsorbent polymers or liquid-absorbent fibers are used in absorbent cores. For example, absorbent articles equipped with an absorbent body (SAP sheet) made of superabsorbent polymers have a thin absorbent body at the beginning of wear before absorbing excrement (liquid), making the absorbent article less noticeable from the outside of clothing. However, once the superabsorbent polymer absorbs excrement, the superabsorbent polymer swells, thickening the absorbent core and making the absorbent article more noticeable from the outside of clothing. Furthermore, when the superabsorbent polymer swells, the rigidity of the absorbent core increases, which can easily cause discomfort to the wearer. On the other hand, absorbent articles that have liquid-absorbent fibers in the absorbent core have relatively low rigidity both before and after absorbing excrement, and are less likely to cause discomfort to the wearer. However, in order for the absorbent core to have the desired absorption function, it is necessary to provide a large amount of liquid-absorbent fibers in the absorbent core. This large amount of liquid-absorbent fibers increases the thickness of the absorbent core, making the absorbent article more noticeable from outside the clothing when the article is first worn and after absorbing excrement.

[0074] When a weight W is placed on a folded diaper 1 for 24 hours and then the weight W is removed, the thinner the thickness of the diaper 1 at the center in the width direction (center C-C) of the folded portion F, the thinner the thickness of the diaper 1 before wearing. The diaper 1 of the present invention is a thin diaper having a thickness of 6.5 mm or less at the center in the width direction (center C-C) of the folded portion F of the diaper 1 after the weight W is removed, and is also provided with cellulose fibers and superabsorbent polymer (SAP) and low basis weight regions 211, 221, 231 along the longitudinal direction.

[0075] As shown in Fig. 5 etc., the absorbent core 20A has low basis weight regions 211, 221, 231 along the longitudinal direction. That is, at least one of the skin side layer 21, the intermediate layer 22, and the non-skin side layer 23 has a basis weight (i.e., the total basis weight of the liquid-absorbent fiber 201 and SAP: g / m) of the absorbent core 20A that is lower than the surrounding area. 2) is low. In the absorbent body 20 of this embodiment, as shown in FIG. 4 etc., the skin side layer 21 and the intermediate layer 22 have low basis weight regions 211, 221 along the longitudinal direction. Similarly, the non-skin side layer 23 also has a low basis weight region 211 where the basis weight of the absorbent core 20A (i.e., the total basis weight of the liquid-absorbent fibers 201 and SAP: g / m 2 ) has a low basis weight region 231 along its length.

[0076] The diaper 1 also contains cellulose fibers (so-called pulp fibers) and superabsorbent polymers (SAPs). The low-basis-weight regions 211, 221, and 231 allow the wearer to excrete in the diaper 1 and the absorbent body 20 to quickly absorb the excreted liquid from the low-basis-weight regions 211, 221, and 231 into the absorbent body 20 (inside each absorbent core 20A). Cellulose fibers are soft and have a fast absorption rate, while superabsorbent polymers have high liquid-retention properties, which facilitate the diffusion of excreta in the longitudinal and thickness directions of the absorbent core 20A. Therefore, when the diaper 1 (absorbent body 20) receives excreta during wear, the cellulose fibers and superabsorbent polymers provide adequate absorption while facilitating the diffusion of absorbed excreta, thereby reducing the risk of excreta being locally absorbed in the region receiving the excreta (crotch region).

[0077] Furthermore, when the absorbent core 20A includes multiple absorbent layers, it is preferable that the low basis weight region 211 of the absorbent layer located on the skin side (skin side layer 21) is a slit that penetrates the skin side layer 21 in the thickness direction. In this case, excrement falls into the low basis weight region 211, increasing the migration rate of the excrement from the skin side layer 21 to the intermediate layer 22. When the low basis weight region 211 is a slit, some liquid-absorbent fibers 201 or SAP may be present, as long as at least a portion thereof has a portion that penetrates in the thickness direction.

[0078] The low basis weight regions 211, 221, and 231 of the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 are not limited to those described above. The shape, size, number, and location of the low basis weight regions 211-231 in each layer can be arbitrarily changed. For example, each layer may have one low basis weight region 211-231, and the low basis weight regions 211-231 may be located on the center line CC in the width direction of the absorbent cores 21-23. The low basis weight regions 211, 221, and 231 in each layer 21, 22, and 23 may be configured such that a portion of each layer 21, 22, and 23 is recessed in the thickness direction. The low basis weight regions 211, 221, and 231 only need to have a portion along the longitudinal direction, and may also have a portion along any direction other than the portion along the longitudinal direction. When the absorbent core 20A has multiple absorbent layers, at least one layer may have a low basis weight region.

[0079] Furthermore, since the absorbent core 20A tends to expand in proportion to the amount of body exudates absorbed, by setting the thickness of the folded portion F of the diaper 1 in the absorbing state to 20.3 mm or less, the risk of the diaper 1 becoming excessively thick due to the absorption of body exudates during wear can be reduced compared to when the thickness of the folded portion F of the diaper 1 in the absorbing state is greater than 20.3 mm. This reduces the risk of the absorber 20 expanding and sagging downwards or causing clothing to bulge due to the absorber 20, making the diaper 1 noticeable from the outside of clothing, even after the diaper 1 has absorbed body exudates.

[0080] Furthermore, the lower the value obtained in the torsion test of the diaper 1, the lower the torsional rigidity of the diaper 1, making it easier to make the diaper 1 flexible. The higher the value obtained in the torsion test, the higher the torsional rigidity of the diaper 1, making the diaper 1 stiffer and more likely to cause discomfort to the wearer. Therefore, if the torsion test value of the diaper 1 in an absorbed state is 44.1 mN·m or less, the diaper 1 can be softer even after absorbing excrement than if the torsion test value was greater than 44.1 mN·m, making it easier to fit the wearer's body and movements, and making the diaper 1 less stiff, thereby reducing discomfort when worn.

[0081] Therefore, the diaper 1 has a relatively thin shape, with the thickness of the folded portion F being 6.5 mm or less before it is worn and before it absorbs excrement, yet it reduces the risk of the diaper 1 swelling excessively even after absorbing excrement, which would be noticeable from the outside of clothing or cause discomfort when worn.

[0082] The "folded state" refers to a state in which the diaper 1 in the unfolded state (see Fig. 2) is folded at a fold F at the center CL in the longitudinal direction, and in the case of a pants-type disposable diaper 1, this refers to the pants-type state shown in Fig. 1. In the case of an absorbent article such as a tape-type disposable diaper or an absorbent pad, it is sufficient that the absorbent article is folded at a fold at the center in the longitudinal direction of the unfolded absorbent article, and the fold in the folded state does not necessarily correspond to the lower end of the absorbent article when worn.

[0083] <<<About the state where weight W is placed on diaper 1>>> Generally, absorbent articles such as diapers 1 are stored under a certain pressure in the form of a package in which they are distributed and stored as a commodity. The effect of the pressure applied to the diaper 1 varies depending on the state of storage, and the thickness of the center of the width direction of the folded portion F of the diaper 1 changes depending on the pressure applied to the diaper. Therefore, after removing the diaper 1 from the package, a weight W (with a base area of 150 cm) is placed on the folded diaper 1. 2 By placing a weight of 5 kg on the diaper for 24 hours, the pressure applied to the diaper 1 is equalized.

[0084] As shown in FIG. 8 , the diaper 1 folded in half (in a pants-type state) is placed on a flat surface with either the front waistline portion 30 or the rear waistline portion 40 facing downward. Then, a weight W is placed on the diaper 1 from above so that the widthwise center of the absorbent main body 10 (the center CC of the diaper 1) is aligned with the widthwise center of the weight W and the weight W fits inside the absorbent main body 10 when viewed in the thickness direction. FIG. 8 is a diagram illustrating the state in which the weight W is placed on the diaper 1. In this embodiment, the diaper 1 is placed on a flat surface with the front waistline portion 30 facing downward and the rear waistline portion 40 facing upward, and the weight W is placed on the rear waistline portion 40 side. In FIG. 8 , the weight W may be placed on one diaper 1 or on a stack of multiple diapers 1. Because absorbent articles such as diapers 1 are lightweight, even when multiple diapers 1 are stacked, the difference in pressure applied to each diaper 1 is within the margin of error and is virtually negligible. However, when multiple absorbent articles are stacked, the number of stacked articles must be such that the stacked state of the absorbent articles can be maintained and the stacked number does not cause the absorbent articles to collapse. In this embodiment, five diapers 1 were stacked in the thickness direction (front-to-back direction), and a weight W was placed on top of them, and the stack was left to stand for 24 hours, and the thickness of all diapers 1 was measured using the method described below.

[0085] The weight W has a base area of 150 cm 2 In this embodiment, a rectangular weight W is used, the length Lw1 in the longitudinal direction (vertical direction) is 15 cm, and the length Lw2 in the width direction is 10 cm (Lw1 × Lw2 = 150 cm). 2 ) Since the weight of the weight W is 5 kg, a pressure of 3267 Pa is applied to the diaper 1 on which the weight W is placed. The weight W can be made of any material, and for example, a metal weight such as stainless steel or iron can be used.

[0086] <<<About absorption state>>> The "absorbed state" refers to the state in which the diaper 1 is in an unfolded and stretched state with the weight W removed from the diaper 1 described above, after 40 ml of artificial urine is dropped over 5 seconds onto the skin-side surface of the diaper 1 at a position 50 mm forward of the center C-C in the longitudinal direction and at the center CC in the width direction, and this drop is repeated three times to allow the diaper 1 to absorb the artificial urine. The amount of excrement absorbed by the diaper 1 when worn varies, and this absorption state is considered to be equivalent to the average state in which the diaper 1 absorbs excrement when worn.

[0087] 9 is a diagram illustrating the process for bringing the diaper 1 into an absorbent state. Specifically, first, the weight W is placed on the diaper 1 as described above and left for 24 hours, and then the weight W is removed from the diaper 1. 9, the drip position Pt is a position 50 mm forward from the longitudinal center of the diaper 1 in the unfolded and stretched state and at the center CC in the width direction. This drip position Pt is the position where urination occurs when the diaper 1 is worn. The cylinder EN is placed on the skin-side surface of the diaper 1 in an unfolded and stretched state. At this time, the center of the cylinder EN is aligned with the drip position Pt. The cylinder EN is a hollow cylindrical body with an inner diameter Li of 60 mm, an outer diameter Lo of 70 mm, and a height of 50 mm. Although the artificial urine is dripped toward the drip position Pt, there is a risk of slight error or splashing. Therefore, by providing the cylinder EN, the artificial urine is more easily absorbed in the area corresponding to the urination position when the diaper 1 is worn. The artificial urine used was prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride, and about 1 g of dye, Blue No. 1, in 10 L of ion-exchanged water. Then, the first drop of 40 ml of artificial urine is dropped onto the dropping position Pt (inside the cylinder EN) over 5 seconds. One minute after the start of the first drip of artificial urine, a second drip of 40 ml of artificial urine is dripped onto the drip position Pt over 5 seconds. One minute after the start of the second drip of artificial urine, a third drip of 40 ml of artificial urine is dripped onto the drip position Pt over 5 seconds. The state in which the diaper 1 has absorbed the artificial urine is called an absorbed state.

[0088] <<<Measuring the thickness of the folded part F of the diaper 1>>> The thickness of the widthwise center (center C-C) of the folded portion F of the diaper 1 after the weight W has been placed for 24 hours and the thickness of the widthwise center (center C-C) of the folded portion F of the diaper 1 in an absorbent state can be measured in the same manner, using a well-known method, such as an Ozaki Seisakusho Dial Thickness Gauge, Large Type JB with spring, or an equivalent. Specifically, using an Ozaki Seisakusho Dial Thickness Gauge Large Type JB with spring, the measurement point (the center of the width of the folded part F) is clamped between a pair of measuring terminals st, and a value of 9.0-12.0 gf / cm 2 In this embodiment, a pressure of 10.5 gf / cm is applied. 2 The measurement is performed by applying pressure to the folded portion F. Figure 10 is a diagram illustrating the measurement of the folded portion F. As shown in Figure 10, the pair of measurement terminals st are circular plates each 50 mm in diameter, and are arranged parallel to each other in the vertical direction (thickness direction of the diaper 1). The pair of measurement terminals st sandwich the folded portion F of the diaper 1 in the thickness direction (front-to-back direction), and the maximum value at the point where both measurement terminals st abut against the diaper 1 is measured as the "thickness." At this time, the measurement is performed with the center CC of the folded portion F of the diaper 1 in the width direction and the lower end of the diaper 1 in the longitudinal direction (vertical direction) aligned with the center of the measurement terminals st.

[0089] <<<About the torsion test>>> 11A and 11B are explanatory diagrams of the "torsion test." FIG. 11A shows a measurement method in which the diaper 1 is twisted around a virtual axis Va1 along the width direction of the diaper 1. FIG. 11B 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. In the drawings, the absorbent cores 21-24 are shown to have a rectangular shape to avoid complexity. The torque value of the diaper 1 in the torsion test 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 in an absorbent state) and identify the position where it will be clamped by the chuck 60 of the torque tester. As shown in the left diagrams of Figures 11A and 11B, 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. Another line C2 extending along the width direction is drawn on the diaper 1, and a line C2 extending along the width direction is drawn on the diaper 1, and a line C1 extending along the vertical 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. 11A, 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 absorbent cores 21-24).

[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 11A 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 FIG. 11B, 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 chuck 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 11B 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. 11A) and the torque value when twisting around the virtual axis Va2 (FIG. 11B) 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] Figure 12 shows the measurement results for Diaper 1 and Products A, B, and C. Products A, B, and C are pants-type disposable diapers for infants that are commercially available. Figure 12A shows the measurement results for each diaper, and Figure 12B shows the relationship between the thickness after absorption and the torque value after absorption for the results of Figure 12A. In Figure 12A, "Presence or Absence of Low Basis Weight Section" indicates whether or not the diaper has a low basis weight section along the longitudinal direction. "Absorbent Core" indicates whether the absorbent core contains cellulose fibers or superabsorbent polymer (SAP). "24-Hour Thickness" refers to the thickness of each diaper at the center of the width direction of the folded portion when a weight is placed on each diaper in a folded state for 24 hours and then removed. "Absorbed State Thickness" refers to the thickness of each diaper at the center of the width direction of the folded portion in the absorbed state. "Absorbed State Torque Value" refers to the result of a torsion test for each diaper in the absorbed state.

[0098] The results of FIGS. 12A and 12B are specifically as follows. The diaper 1 has low basis weight regions 211, 221 along the longitudinal direction and an absorbent core comprising cellulose fibers and a superabsorbent polymer (SAP). After 24 hours, the thickness was 5.6 mm, the absorbed thickness was 20.3 mm, and the absorbed torque value was 44.1 mN·m. Diaper product A has a low basis weight section along the longitudinal direction and an absorbent core made of cellulose fibers and superabsorbent polymer (SAP). After 24 hours, the thickness was 6.5 mm, the absorbed thickness was 27.9 mm, and the absorbed torque value was 51.8 mN·m. Diaper product B does not have a low basis weight section along the longitudinal direction and has an absorbent core made of cellulose fibers and superabsorbent polymer (SAP). After 24 hours, the thickness was 5.6 mm, the absorbed thickness was 28.5 mm, and the absorbed torque value was 36.6 mN m. Diaper product C has a low basis weight section along the longitudinal direction, no cellulose fibers, and an absorbent core containing only superabsorbent polymer (SAP). After 24 hours, the thickness was 5.6 mm, the absorbed thickness was 31.2 mm, and the absorbed torque value was 46.5 mN m.

[0099] Product A has an absorbent core made of cellulose fibers and SAP fibers, and a low basis weight section along the longitudinal direction, which allows it to have adequate absorption capabilities while also dispersing body waste. Because Product A's thickness after weight W is removed is 6.5 mm, it is not thick enough to be noticeable from the outside of clothing immediately after wearing (before absorbing body waste). However, Product A's absorbed thickness is 27.9 mm and its absorbed torque value is 51.8 mN·m, so after absorbing body waste, Product A is more noticeable from the outside of clothing than Diaper 1, and the stiffness of Product A is more likely to cause discomfort to the wearer.

[0100] Product B has an absorbent core made of cellulose fibers and SAP fibers, and a low basis weight section along the longitudinal direction, providing adequate absorption and dispersibility of bodily waste. Product B is 5.6 mm thick when weight W is removed, meaning that it is not thick enough to be noticeable from the outside of clothing immediately after wearing (before absorbing bodily waste). However, in the absorbent state, Product B has a thickness of 28.5 mm, making it more noticeable from the outside of clothing than Diaper 1.

[0101] Product C has liquid retention properties because its absorbent core does not contain cellulose fibers but is made of superabsorbent polymer (SAP). Product B is not thick enough to be noticeable from the outside of clothing immediately after wearing it (before absorbing excrement), as it is 5.6 mm thick when weight W is removed. However, in the absorbent state, Product B has an absorbent state thickness of 27.9 mm and an absorbent state torque value of 51.8 mN·m. Therefore, after absorbing excrement, Product A is more noticeable from the outside of clothing than Diaper 1, and the stiffness of Product A is more likely to cause discomfort to the wearer.

[0102] The graph in Figure 12B shows the results for Diaper 1 and Products A to C in an absorbent state, with the thickness and torque values after absorption decreasing as the position moves to the bottom left. As shown in Figure 12B, Diaper 1 is positioned lower and left than Products A to C. Therefore, it is clear that Diaper 1 reduces the risk of excessive swelling of Diaper 1 and reduces discomfort caused by the diaper 1 becoming stiff, even after absorbing body exudates during wear, compared to Products A to C.

[0103] Furthermore, in the crotch region M, which is located between the crotch of a wearer when the diaper 1 is worn, the absorbent core 20A preferably has a constricted portion 20c that is constricted inward in the width direction. The constricted portion 20c refers to a portion of the absorbent core 20A that is located outward in the width direction from the absorbent core 20A where the width of the absorbent core 20A is partially shortened. As shown in Fig. 5, in this embodiment, the skin-side layer 21 and the intermediate layer 22 have constricted portions 212, 222, and in the longitudinal central portion of the diaper 1, the widthwise length L1 of the non-skin-side layer 23 is longer than the widthwise lengths of the skin-side layer 21 and the intermediate layer 22. The constricted portion 20c of the absorbent core 20A is a region in the longitudinal central portion of the absorbent core 20A that extends from one end of L1 to one end of L2 in the width direction (from the other end of L1 to the other end of L2 in the width direction), and is the region indicated by diagonally downward-slanting lines to the left in Fig. 5. The absorbent core 20A includes the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23, and the constricted portion 20c is a region where the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 are not present when viewed in the thickness direction. The constricted portion 20c needs to be provided at least in the crotch portion M, and may also be provided at the front end or the rear end in the longitudinal direction. For example, the absorbent body 20 may have a T-shaped absorbent core 20A in which a substantially rectangular absorbent core 20A extending along the longitudinal direction is provided in the longitudinal center at the widthwise center, a substantially rectangular absorbent core 20A extending along the widthwise direction is provided at the longitudinal front end, and no absorbent core 20A extending along the widthwise direction is provided at the longitudinal rear end, and the absorbent core 20A in the longitudinal center and the absorbent core 20A at the widthwise front end are continuous. In such a case, the portion adjacent to the absorbent core 20A from the outer side in the width direction along the longitudinal direction becomes the constricted portion 20c. Note that, in a pants-type state, the crotch portion M refers to the portion below the portion overlapping with the side joint portion 2 in the up-down direction (toward the center CL in the longitudinal direction), and in the case of absorbent articles other than pants-type disposable diapers, it refers to the central region when the skin side layer 21 and the intermediate layer 22 are divided into thirds along the maximum length in the longitudinal direction.

[0104] The crotch region M of the diaper 1 is the region that is sandwiched between the wearer's legs when the diaper 1 is worn. Therefore, by providing the absorbent core 20A with the constricted region 20c in the crotch region, the diaper 1 can be more easily fitted to the shape of the wearer's body when worn, allowing the wearer to move their legs more easily. Furthermore, even when the diaper 1 absorbs excrement and the absorbent core 20A expands, the constricted region 20c can be less likely to impede the wearer's leg movement.

[0105] Here, the widthwise length L1 of the non-skinside layer 23 refers to the length from one widthwise end 23ae of the divided region 23a of the non-skinside layer 23 to the other widthwise end 23ce of the divided region 23c. The non-skinside layer 23 has a portion longer than the widthwise lengths of the skinside layer 21 and the intermediate layer 22, allowing the non-skinside layer 23 to absorb excrement that was not absorbed by the skinside layer 21 and the intermediate layer 22, thereby preventing leakage. Furthermore, the number of layers decreases in the longer widthwise portions of the non-skinside layer 23, resulting in reduced rigidity. By providing a region with reduced rigidity within the range of the constricted portions 212, 222, the fit around the crotch area is improved when worn.

[0106] The superabsorbent polymer contained in the absorbent core 20A of the diaper 1 preferably has a liquid absorption rate of 40 seconds or more as measured by the vortex method. The longer the absorption time as measured by the vortex method, the slower the liquid absorption rate. The superabsorbent polymer contained in the absorbent core 20A refers to the SAP contained in the entire absorbent core 20, specifically, the superabsorbent polymer provided in all layers, including the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23.

[0107] In the absorbent core 20A, when excrement is absorbed during wear, the excrement is more likely to diffuse within the absorbent core 20A than if it were absorbed by the superabsorbent polymer via the vortex method in a manner faster than 40 seconds. This allows the superabsorbent polymer to locally absorb excrement, reducing the risk of the absorbent core 20A swelling locally. This reduces the risk of the diaper 1 becoming excessively stiff in parts, making it easier to soften the diaper 1 after absorption. This reduces the risk of the diaper 1 being noticeable from the outside of clothing, reduces discomfort to the wearer, and is less likely to restrict the wearer's leg movement, even after excrement has been absorbed.

[0108] The liquid absorption rate of SAP by the vortex method can be measured by a known method. For example, 50.0 ml (±0.5 ml) of saline solution with a concentration of 0.900% (±0.009%) and a temperature of 25°C (±2°C) is placed in a 100 ml beaker. The beaker is then placed on a magnetic stirrer and the stir bar is placed inside the beaker. The stir bar is then rotated at 600 rpm (±30 rpm) to ensure that the saline solution in the beaker forms a stable vortex. A stopwatch is then started from the moment 2.00 g (±0.02 g) of the SAP to be measured, taken from Diaper 1, is placed in the beaker. The time from when the vortex disappears and the liquid level becomes horizontal is measured. The longer this time, the slower the liquid absorption rate.

[0109] Furthermore, it is preferable that the absorbent core 20A has multiple absorbent layers (a first absorbent layer and a second absorbent layer), and that the low-basis-weight sections of the absorbent core 20A have a first low-basis-weight section in the first absorbent layer and a second low-basis-weight section in the second absorbent layer, with the first low-basis-weight section and the second low-basis-weight section overlapping each other in the thickness direction of the diaper 1. This ensures the absorption function of the diaper 1 through the multiple absorbent layers, while the first low-basis-weight section and the second low-basis-weight section, which overlap in the thickness direction, improve the diffusion of body exudates in the thickness direction of the absorbent core 20A. As a result, it is possible to reduce the risk of the absorbent core 20A becoming locally thick in areas of the diaper 1 that receive body exudates.

[0110] The absorbent core 20A of the diaper 1 of this embodiment has a skin-side layer 21, an intermediate layer 22, and a non-skin-side layer 23. As low basis weight portions, the skin-side layer 21 has a low basis weight region 211, the intermediate layer 22 has a low basis weight region 221, and the non-skin-side layer 23 has a low basis weight region 231. When viewed in the thickness direction of the diaper 1, as shown in Fig. 5, there is an overlapping portion between the low basis weight region 211 (first low basis weight portion) of the skin-side layer 21 (first absorbent layer) and the low basis weight region 231 (second low basis weight portion) of the non-skin-side layer 23 (second absorbent layer). This facilitates the diffusion of body waste in the thickness direction, such that the body waste flows from the low basis weight region 211 of the skin-side layer 21 into the low basis weight region 231 of the non-skin-side layer 23 (second absorbent layer), and reduces the risk of the absorbent core 20A becoming locally thick in the diaper 1 at the portion where the body waste is received.

[0111] Furthermore, the thickness direction may not be limited to the skin side layer 21 (first absorbent layer) and the non-skin side layer 23 (second absorbent layer), and the low basis weight region 211 (first low basis weight portion) of the skin side layer 21 (first absorbent layer) may have an overlapping portion with the low basis weight region 221 (second low basis weight portion) of the intermediate layer 22 (second absorbent layer), or the low basis weight region 221 (first low basis weight portion) of the intermediate layer 22 (first absorbent layer) may have an overlapping portion with the low basis weight region 231 (second low basis weight portion) of the non-skin side layer 23 (second absorbent layer). In this embodiment, the thickness direction has an overlapping portion with the low basis weight region 211 of the skin side layer 21, the low basis weight region 221 of the intermediate layer 22, and the low basis weight region 231 of the non-skin side layer 23. Therefore, the absorbent core 20A can diffuse body waste in the thickness direction by each of the low basis weight regions 211, 221, 231 so that the body waste falls directly from the low basis weight region 211 to the low basis weight region 231, thereby reducing the risk of the absorbent core 20A swelling locally in the area where the body waste has been received. Furthermore, the low basis weight regions 211, 221, 231 of this embodiment are each aligned along the longitudinal direction, which more easily promotes the diffusion of body waste in the longitudinal direction.

[0112] Of the multiple absorbent layers included in the absorbent core 20A, it is preferable to have a non-skin side layer 23 (SAP layer) formed solely from a superabsorbent polymer, which is provided closest to the skin side. It is also preferable to have an intermediate sheet between this non-skin side layer 23 and an absorbent layer (intermediate layer 22) provided closer to the skin side than the non-skin side layer 23. In this embodiment, the non-skin side layer 23, which is located closest to the skin side of the absorbent core 20A, is formed solely from a superabsorbent polymer. A nonwoven fabric 27 is provided between the non-skin side layer 23 and the intermediate layer 22 provided closer to the skin side than the non-skin side layer 23. By providing the non-skin-side layer 23 formed solely from a highly liquid-retentive superabsorbent polymer on the non-skin-side side of the absorbent core 20A and providing the intermediate sheet 27 on the skin-side side of the non-skin-side layer 23, excrement is more likely to diffuse in the planar direction on the nonwoven fabric 27 before transferring from the intermediate layer 22 to the non-skin-side layer 23, thereby reducing the risk of the absorbent core 20A becoming locally thick and providing the diaper 1 with an appropriate excrement absorption function. Note that the intermediate sheet (nonwoven fabric 27) provided between the non-skin-side layer 23 and the absorbent layer (intermediate layer 22) provided on the skin-side side of the non-skin-side layer 23 is not limited to nonwoven fabric, and may be a sheet material such as tissue.

[0113] Furthermore, it is preferable that the absorbent core 20A has multiple absorbent layers (first and second absorbent layers), and that the side edges of the first and second absorbent layers are located at different positions on one side in the width direction. This allows for an area on one side in the width direction of the absorbent core 20A where either the first or second absorbent layer is absent, making it easier to reduce the rigidity and torsional rigidity of the side edge on one side in the width direction of the absorbent core 20A, thereby reducing discomfort around the wearer's legs and reducing the risk of leg movement being hindered.

[0114] The absorbent core 20A of the diaper 1 of this embodiment has a skin-side layer 21, an intermediate layer 22, and a non-skin-side layer 23. On one side in the width direction, the side edge of the skin-side layer 21 (first absorbent layer) and the side edge of the non-skin-side layer 23 (second absorbent layer) are located at different positions. Specifically, as shown in FIG. 5 , the maximum length L2 of the skin-side layer 21 is longer than the maximum length L3 (and similarly, L1) of the non-skin-side layer 23. This facilitates reducing the rigidity and torsional rigidity of the side edge of the absorbent core 20A on one side in the width direction, thereby reducing discomfort around the wearer's legs and reducing the risk of restricting leg movement. Furthermore, in the longitudinal center of the diaper 1, the skin-side layer 21 has a portion narrower than the width (L1) of the non-skin-side layer 23, which reduces the amount of absorbent core 20A that comes into contact with the wearer's skin in the crotch region, resulting in a comfortable fit against the wearer's skin. Furthermore, since the maximum length L2 of the skin-side layer 21 and the intermediate layer 22 is longer than the maximum length L3 of the non-skin-side layer 23 in areas other than the central portion in the longitudinal direction, excrement can be absorbed and diffused effectively in areas closer to the skin than the non-skin-side layer 23. Similarly, in the diaper 1, the side edge of the intermediate layer 22 (first absorbent layer) and the side edge of the non-skin-side layer 23 (second absorbent layer) are located at different positions on one side in the width direction. Specifically, in the width direction, the maximum length L2 of the intermediate layer 22 is longer than the maximum length L3 (and similarly, L1) of the non-skin-side layer 23.

[0115] Preferably, the absorbent core 20A has multiple absorbent layers (a first absorbent layer and a second absorbent layer), with one longitudinal end of the first absorbent layer and one longitudinal end of the second absorbent layer located at different positions. This allows for a region on one longitudinal side of the absorbent core 20A where either the first or second absorbent layer is absent, thereby reducing the rigidity and torsional rigidity of the end on one longitudinal side of the absorbent core 20A and allowing the absorbent core 20A to move flexibly in accordance with the wearer's body shape and movements. Furthermore, having a region on one longitudinal side of the absorbent core 20A where either the first or second absorbent layer is absent allows for a thinner absorbent core 20A on at least one of the front and back sides of the diaper 1, which reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption.

[0116] The absorbent core 20A of the diaper 1 of this embodiment has a skin-side layer 21, an intermediate layer 22, and a non-skin-side layer 23. On one side (e.g., the front side) in the longitudinal direction, one end (front end) of the skin-side layer 21 (first absorbent layer) and one end (front end) of the non-skin-side layer 23 (second absorbent layer) are located at different positions. Specifically, as shown in FIG. 5 , the length L4 of the skin-side layer 21 is longer than the length L5 of the non-skin-side layer 23 in the longitudinal direction. This facilitates reducing the rigidity and torsional rigidity of one longitudinal side end of the absorbent core 20A, thereby reducing discomfort around the wearer's legs and reducing the risk of restricting leg movement. By facilitating reducing the rigidity and torsional rigidity of one longitudinal end (front end) of the absorbent core 20A, the absorbent core 20A can flexibly move in accordance with the shape and movement of the wearer's body when worn. In addition, since the absorbent core 20A has a thin portion at one longitudinal end, the risk of the diaper 1 on one longitudinal side (front end) of the absorbent core 20A being noticeable from the outside of the garment after absorption is reduced.

[0117] As described above, the absorbent core 20A has the skin-side layer (absorbent core) 21, the intermediate layer (absorbent core) 22, and the non-skin-side layer (absorbent core) 23. The intermediate layer 22 is located closer to the skin in the thickness direction than the skin-side layer 21, and the non-skin-side layer 23 is located closer to the skin in the thickness direction than the intermediate layer 22. The skin-side layer 21 has a first thickness t1, and is a layer in which the volume occupied by SAP is larger than the volume occupied by liquid-absorbent fibers (cellulose fibers) 201. The intermediate layer 22 has a second thickness t2, and is a layer (pulp layer) in which the volume occupied by liquid-absorbent fibers 201 is larger than the volume occupied by SAP. The non-skin-side layer 23 has a third thickness t3, and is a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by liquid-absorbent fibers 201. When excrement is received while the absorbent core is being worn, the skin-side layer 21, which has a high volume occupancy rate of SAP, first absorbs the excrement, while the low basis weight regions 211 promote diffusion of the excrement to the non-skin side in the longitudinal and thickness directions. Then, in the intermediate layer 22, which has a high volume occupancy rate of liquid-absorbent fibers 201, excrement that migrates from the low basis weight regions 211 to the intermediate layer 22 is quickly and temporarily absorbed by the intermediate layer 22. Subsequently, the excrement absorbed between the liquid-absorbent fibers 201 in the intermediate layer 22 gradually migrates to the non-skin side layer 23 due to gravity. Furthermore, since the intermediate layer 22 also has a low basis weight region 221, excrement tends to migrate 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 facilitates the excrement to be drawn deep into the absorbent core, improving absorbency. Furthermore, since the volume occupancy of SAP in the non-skinside layer 23 is high, excrement is firmly absorbed and retained by the SAP of the non-skinside layer 23. This allows the absorbent core 20A to have the desired absorption function and flexibility while being thin, which makes it easier to fit the wearer's body and movements and reduces the risk of the diaper 1 being noticeable from the outside of clothing even after absorbing excrement.

[0118] In the diaper 1 of this embodiment, the absorbent core 20A has multiple absorbent layers, arranged in this order from the skin side to the non-skin side: a skin-side layer 21 in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fiber 201; an intermediate layer 22 in which the volume occupied by the liquid-absorbent fiber 201 is larger than the volume occupied by SAP; and a non-skin-side layer 23 in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fiber 201.This makes it easier to promote planar diffusion of the absorbent core 20A and diffusion in the thickness direction from the skin side to the non-skin side when the diaper 1 (absorbent body 20) receives excrement while being worn, so that the excrement is absorbed locally only in the area that receives the excrement, reducing the risk of the absorbent core 20A swelling locally. This allows the thickness of the absorbent core 20A to be thin before absorbing bodily waste, while reducing the risk of the absorber 20 of the diaper 1 expanding excessively even after absorbing bodily waste, so that the thickness of the widthwise center of the folded portion F of the diaper 1 when the weight W is removed can be 6.5 mm or less, the thickness of the widthwise center of the folded portion F of the diaper 1 in the absorbent state can be 20.3 mm or less, and the torsion test value of the diaper 1 in the absorbent state can be 44.1 mN·m or less. This reduces the risk of the diaper 1 being noticeable from the outside of clothing or causing discomfort to the wearer.

[0119] 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."

[0120] 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.

[0121] Furthermore, a skin-side upper layer 24 is provided closer to the skin than the skin-side layer 21 in the thickness direction. The skin-side upper layer 24 has a fourth thickness t4 that is thinner than the first thickness t1 of the skin-side layer 21 and the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by the SAP. Since the skin-side upper layer 24, which has a high volume occupancy rate of the liquid-absorbent fibers 201, is located closer to the skin than the skin-side layer 21, the wearer's perception of the unevenness of the SAP can be further reduced. Furthermore, because the skin-side upper layer 24 is a layer with a high content of the liquid-absorbent fibers 201, it improves the ability to draw excreted liquid from sheets (such as a top sheet) placed closer to the skin. Furthermore, the liquid-absorbent fibers 201 contained in the skin-side upper layer 24 make it difficult for the SAP of the skin-side layer 21 to roll within the layer, preventing a deterioration in the tactile feel. The skin-side upper layer 24 is positioned closer to the skin than the skin-side layer 21, but is thinner than the first thickness t1 of the skin-side layer 21, so it can absorb excreted liquid without excessively retaining the excreted liquid, thereby reducing rewetting.

[0122] As described above, 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 ). 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 average thickness of the absorbent core 20 is preferably 2.0 to 2.5 mm.

[0123] 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.

[0124] The thicknesses (t1 to t3) of the layers 21 to 23 can be measured using a known method. For example, with the diaper 1 in a natural, dry state without any external force, the diaper 1 (absorbent body 20) is cut widthwise at any longitudinal position in 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 raised toward 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. In addition, when multiple absorbent layers are bonded to adjacent sheet portions (core wrap sheets 25, 26, intermediate sheet 27) via adhesive, it is difficult to identify the parts where the material (cellulose fiber, SAP) constituting each absorbent layer is actually bonded and fixed to the adjacent sheet portion with adhesive.Therefore, when it can be determined that adhesive exists between the absorbent layer and the adjacent sheet portion, the distance between adjacent sheet portions in the thickness direction is measured as the "thickness of the absorbent layer."

[0125] 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.

[0126] In the absorbent core 20A of the diaper of this embodiment, the average basis weight of the non-skinside layer 23 is higher than the average basis weight of the skinside layer 21. The preferred average basis weight of the non-skinside 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 2The 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 with a low average basis weight is less likely to swell after retaining water, and therefore the skin side layer 21 is less likely to suffer from absorption inhibition due to swelling of SAP. As a result, the feel of the skin side (gritty feeling of SAP) is less likely to deteriorate.

[0127] Furthermore, it is preferable that the average total area occupied by SAPs per unit area in a cross section taken along the thickness direction of the skin-side layer 21 is greater than the average total area occupied by SAPs per unit area in a cross section taken along the thickness direction of the non-skin-side layer 23. This makes it easier for the non-skin-side layer 23 comprising SAP to retain body exudates than the skin-side layer 21 comprising SAP in the absorbent core 20A. This reduces the risk of localized swelling of the skin-side layer 21 due to the exudates absorbed through the skin-side surface of the absorbent core 20A being retained by the skin-side layer 21. Reducing localized swelling of the absorbent core 20A and lowering the torsional rigidity of the diaper 1 makes it easier for the diaper 1 to fit the wearer's body and reduces discomfort during wear. It also reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption. On the other hand, the non-skin side layer 23, which has a larger average value of the total area occupied by SAP per unit area, has higher liquid retention than the skin side layer 21, and therefore reduces the risk of excrement once absorbed by the non-skin side layer 23 rewetting toward the skin side layer 21, even in the case of repeated excrement.

[0128] The "average value of the total area occupied by SAPs per unit area in a cross section taken along the thickness direction of the skin-side layer 21 (non-skin-side layer 23)" can be determined, for example, using the volume comparison method described above, as follows: The absorbent body 20 is cut at 10 locations along the width direction at any position in the longitudinal direction of the absorbent body 20, specifically, at a location where the skin-side layer 21 and the non-skin-side layer 23 are laminated and away from the product folding position. The cut surfaces are photographed under magnification using the optical microscope, and the "total area occupied by SAPs per unit area" of the skin-side layer 21 and the "total area occupied by SAPs per unit area" of the non-skin-side layer 23 are determined for each of the cut surfaces, and their average value is defined as the "average value of the total area occupied by SAPs per unit area."

[0129] Furthermore, it is preferable that the total water retention capacity of the superabsorbent polymer present in the skin-side layer 21 is less than the total water retention capacity of the superabsorbent polymer present in the non-skin-side layer 23. This allows the non-skin-side layer 23 of the absorbent core 20A to retain excrement (liquid) more easily than the skin-side layer 21, thereby reducing the risk of localized swelling of the absorbent core 20A at the portion where excrement is received on the skin-side surface of the absorbent core 20A during wear, and helping to reduce the risk of localized swelling of the diaper 1 after absorption being noticeable from the outside of clothing. In other words, the skin-side layer 21, which has a low total water retention capacity, reduces the risk of the superabsorbent polymer swelling and inhibiting excrement absorption, and the skin-side layer 21 is more likely to promote rapid absorption and diffusion of excrement. Furthermore, the non-skin-side layer 23, which has a high total water retention capacity, retains excrement diffused on the skin side of the non-skin-side layer 23, helping to reduce localized swelling of the absorbent core 20A. Furthermore, the torsional rigidity of the diaper 1 is reduced, making it easier to fit the wearer's body, and reducing discomfort when worn.

[0130] Furthermore, although the skin-side layer 21 has a smaller total water retention capacity than the non-skin-side layer 23, it has a high volume occupancy rate of SAP and therefore has adequate water retention. Therefore, when excreted fluid from the intermediate layer 22 or the non-skin-side layer 23 attempts to return to the skin side, the SAP of the skin-side layer 21 absorbs and retains the excreted fluid, preventing the excreted fluid from rewetting.

[0131] The total water retention capacity of SAP present in the skin-side layer 21 and the non-skin-side layer 23 can be measured by the following measurement method. First, 0.9% saline solution (enough to fully immerse the sample) is prepared in a water bath. Next, a test piece is prepared. The test pieces are cut into 50 mm pieces in the longitudinal direction of one absorbent body 20. When the absorbent body 20 is cut into 50 mm pieces, the length of the last test piece in the longitudinal direction does not have to be less than 50 mm. First, in order to measure the total water retention capacity of the SAP present in the skin side layer 21, each test piece is separated as follows. (Layer separation method 1) 1) Peel off the core wrap sheet 26 from the non-skin side. 2) Peel off the non-skin side layer 23 3) Peel off the nonwoven fabric 27 4) Peel off the layer of liquid absorbent fiber 201 (corresponding to the intermediate layer 22) of the remaining sheet. 5) The sum of 1) to 4) above is X1. 6) The part other than X1 is designated as X2 (X2 essentially includes the skin side layer 21, the skin side upper layer 24, and the core wrap sheet 25). As the next test piece, an absorbent body 20 different from the one absorbent body described above is prepared and similarly cut into 50 mm pieces in the longitudinal direction. To measure the total water retention capacity of the SAP present in the non-skin side layer 23, each cut test piece is separated as follows. (Layer separation method 2) 1) Peel off the core wrap sheet 25 from the skin side. 2) Of the remaining sheet, the layer of liquid absorbent fiber 201 (corresponding to the middle layer 22) is not peeled off (this results in peeling off the skin-side upper layer 24, the skin-side layer 21, and the middle layer 22). 3) Peel off the nonwoven fabric 27 4) The above 1) to 3) are X4 5) The portion other than X4 is designated as X3 (X3 essentially includes the non-skin side layer 23 and the core wrap sheet 26).

[0132] Next, samples X1 to X4 are each placed in a mesh plastic bag, sealed, and their weight (A) before water absorption is measured. After measurement, each sample X1 to X4 is immersed in saline for 30 minutes. After 30 minutes, each sample is removed from the water bath, and with the core wrap sheet side of each sample facing downwards, an acrylic plate (320 x 545 mm, 3 to 5 mm thick, weighing 400 to 600 g) and a 5 kg weight are placed on top, and left for 20 minutes. After 20 minutes, the weight and acrylic plate are removed, and the weight (B) of each sample is measured. Weight (B) - Weight (A) is the amount of water absorbed.

[0133] After weight measurement, each sample was dehydrated using a centrifuge at 75G for 90 seconds. After dehydration, the weight (C) of each removed sample was measured. Weight (C) minus weight (A) is the water retention capacity. Note that dehydration using a centrifuge removes water adhering to the liquid absorbent fiber 201, core wrap sheet, and nonwoven fabric, and only the amount of water chemically retained by the SAP is determined. Therefore, the water retention capacity calculated by "weight (C) minus weight (A)" is the water retention capacity of the SAP present in each sample. Therefore, the water retention capacity of sample X2 is the water retention capacity of the SAP present in the skin-side layer 21, and the water retention capacity of sample X3 is the water retention capacity of the SAP present in the non-skin-side layer 23. In this embodiment, in order to compare the "total water retention capacity" of SAP present in the skin-side layer 21 with the "total water retention capacity" of SAP present in the non-skin-side layer 23, measurements were carried out on each test piece cut into 50 mm pieces as described above, and the sum of the water retention capacity of X2 of each test piece is the "total water retention capacity of SAP present in the skin-side layer 21," and the sum of the water retention capacity of X3 of each test piece is the "total water retention capacity of SAP present in the non-skin-side layer 23."

[0134] As an example, the water retention capacity of the above-mentioned X2 (one sample) was 25.4 g, and the water retention capacity of the above-mentioned X3 (one sample) was 41.1 g. In other words, when comparing the water retention capacities of test pieces with a longitudinal length of 50 mm, the water retention capacity of the SAP present in the non-skinside layer 23 was clearly greater. Therefore, it can be seen that in the diaper 1 of this embodiment, the total water retention capacity of the SAP present in the non-skinside layer 23 is greater than the total water retention capacity of the SAP present in the skinside layer 21.

[0135] Furthermore, it is desirable that the SAP of the skin-side layer 21 have a slower liquid absorption rate, as measured by the vortex method, than the SAP of the non-skin-side layer 23. This facilitates diffusion of excrement in the planar direction or away from the skin side rather than absorption by the skin-side layer 21. This facilitates diffusion of excrement throughout the absorbent core 20A, thereby reducing the likelihood of excrement being retained in only localized areas of the skin-side layer 21 and reducing the risk of localized swelling of the absorbent core 20A. This reduces the risk of the diaper 1 being visible from the outside of clothing after absorption, while also reducing the torsional rigidity of the diaper 1, allowing it to better fit the wearer's body and movements, thereby reducing discomfort to the wearer. Furthermore, absorbing more excrement in the non-skin-side layer 23 reduces rewetting of the skin-side layer 21. The liquid absorption rate of SAP as measured by the vortex method can be measured by a known method, for example, the same method as described above.

[0136] One way to slow down the liquid absorption rate measured by the vortex method of the SAP in the skin-side layer 21 compared to the SAP in the non-skin-side layer 23 is to use different types of SAP, such as SAP with different compositions, shapes, sizes, or arrangements, for the SAP used in the skin-side layer 21 and the SAP used in the non-skin-side layer 23.

[0137] Regarding the absorbent core 20A, the density of the absorbent core 20A is 0.2 g / cm 3 It is preferable that the density of the absorbent core 20A is 0.2 g / cm or more. The higher the density of the absorbent core 20A, the thinner the absorbent core 20A can be while increasing the amount of liquid-absorbent fiber (cellulose fiber) and superabsorbent polymer for absorbing excrement. This makes it easier to achieve a thinner absorbent core 20A and improve the diffusion of excrement. Therefore, it is preferable that the density of the absorbent core 20A is 0.2 g / cm or more. 3 By this, the density of the absorbent core 20A is 0.2 g / cm 3Since the absorbent core 20A is made smaller, it is easier to disperse excrement, thereby reducing the risk of localized swelling of the absorbent core 20A. This reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption. In addition, it is easier to reduce the torsional rigidity of the diaper 1, which makes it easier to fit the wearer's body and movements when worn, thereby reducing discomfort when worn.

[0138] As described above, the diaper 1 includes a core wrap sheet 25 that covers the skin-facing side of the absorbent core 20A (skin-side layer 21, skin-side upper layer 24), and a top sheet (surface sheet) 12 that is located closer to the skin than the core wrap sheet 25. The density of the absorbent core 20A and the top sheet 12 is preferably higher than that of the top sheet 12. Having a higher density of the absorbent core 20A than that of the top sheet 12 improves the planar diffusion of excrement in the top sheet 12 compared to when the density of the surface sheet is higher than that of the absorbent core. This allows the planarly dispersed excrement to migrate perpendicularly to the non-skin side in the thickness direction, thereby reducing localized swelling of the absorbent core 20A. This helps reduce the risk of the diaper 1 being noticeable from the outside of clothing after absorption. This also helps reduce the torsional rigidity of the diaper 1, allowing it to better fit the wearer's body and movements, thereby reducing discomfort during wear.

[0139] In addition, the top sheet 12 arranged on the skin side of the core wrap sheet 25 may be arranged on the skin side of the core wrap sheet 25, and may be arranged in a form in which the absorbent body 20 (core wrap sheet 25) and the top sheet 12 are in contact with each other, or one or more sheet members or other components may be arranged between the absorbent body 20 (core wrap sheet 25) and the top sheet 12.

[0140] The absorbent core 20A preferably has a core wrap sheet 25 covering the skin-facing side of the absorbent core 20A (skin-side layer 21, skin-side upper layer 24) and a top sheet (surface sheet) 12 located closer to the skin than the core wrap sheet 25, a core wrap sheet 26 covering the non-skin-facing side of the absorbent core 20A (non-skin-side layer 23), and a back sheet 13 located closer to the skin than the core wrap sheet 26, and preferably has a portion where the top sheet 12 and the back sheet 13 are bonded together. In this embodiment, the back sheet 13 is formed of a back sheet 13a which is a liquid-impermeable sheet and a back sheet 13b which is an exterior sheet. The back sheet 13 has a portion where the non-skin-facing side of the top sheet 12 is bonded to the skin-facing side of the back sheet 13. Note that the portion where the back sheet 13 and the top sheet 12 are bonded together may be a portion where the back sheet 13 and the top sheet 12 are directly bonded together, or a portion where the back sheet 13 and the top sheet 12 are indirectly bonded together via another member.

[0141] By having this adhesive portion between the back sheet 13 and the top sheet 12, it is possible to reduce the number of components overlapped in the thickness direction of the absorbent main body 10 compared to when the top sheet 12 is folded up to the non-skin side (non-skin side) of the core wrap sheet 26 or when the back sheet 13 is folded up to the skin side (skin side) of the core wrap sheet 25. The fewer the number of components overlapped in the thickness direction of the absorbent main body 10, the thinner the absorbent main body 10 can be. This reduces the risk of the diaper 1 being noticeable from the outside of clothing. Furthermore, the thinner the absorbent main body 10 and the diaper 1 are, the lower the rigidity of the diaper 1, which makes it easier for the diaper 1 to fit the wearer's body and movements when worn, and reduces discomfort when worn.

[0142] The layer (skin-side layer 21 or non-skin-side layer 23) comprising a superabsorbent polymer in the absorbent core 20A of the absorbent body 20 may be modified as follows. FIG. 13 is a cross-sectional schematic diagram of the absorbent body 20 showing a modified example of the skin-side layer 21. As shown in FIG. 13, the modified skin-side absorbent layer 21 has a high-basis weight region 213 in which the basis weight of the SAP is higher than that of the surrounding areas. In the high-basis weight region 213, points S at which 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 213 are arranged intermittently in the longitudinal and width directions. Furthermore, between adjacent points S at which the thickness is greatest (i.e., around the high-basis weight region 213), low-basis weight regions 214 in which the basis weight of the SAP is lower than that of the high-basis weight region 213 are formed. However, as long as the points S at which the thickness is greatest are located intermittently in the longitudinal and width directions, part of the area between adjacent points S at which the thickness is greatest may be formed by the high-basis weight region 213. In other words, the high basis weight region 213 may connect adjacent maximum thickness points S to each other.

[0143] The low basis weight region 214 has a low basis weight laminated region 214E where SAP is laminated, and a non-laminated region 214N 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.

[0144] In the absorbent body 20 of this modified example, the low basis weight regions 214 (low basis weight laminated regions 214E and non-laminated regions 214N) serve as folding start points, allowing the absorbent body 20 to easily deform along the contours of the wearer's body, improving fit. Furthermore, the low basis weight regions 214 that serve as folding start points include low basis weight laminated regions 214E that can absorb and retain excrement, and non-laminated regions 214N that are more easily bent due to the absence of SAP. As a result, even in the low basis weight regions 214 where the basis weight of the SAP is lower than that of the high basis weight regions 213, it is possible to achieve both ease of deformation along the contours of the wearer's body and the ability to absorb and retain excrement.

[0145] The absorbent core 20A is not limited to the above-described configuration. For example, a diaper 1 having a widthwise central thickness of 6.5 mm or less at the folded portion F of the diaper 1 after placing a weight W on the diaper 1 in a folded state for 24 hours and then removing the weight W, a widthwise central thickness of 20.3 mm or less at the folded portion F of the diaper 1 in an absorbent state, and a torque value of 44.1 mN·m or less in a torsion test may be configured to include the absorbent core 20A shown in FIG. 14. FIG. 14 is a cross-sectional schematic diagram of a modified absorbent body 20. The absorbent core 20A of the absorbent body 20 shown in FIG. 14 includes liquid-absorbent fibers (cellulose fibers) 201 and SAP (superabsorbent polymer), has a basis weight lower than that of the surrounding area, and includes a low-basis weight region 211 along the longitudinal direction. The modified absorbent core 20A also includes a core wrap sheet 25 covering at least a portion of the skin-facing side of the absorbent core 20A, and a core wrap sheet 26 covering at least a portion of the non-skin-facing side of the absorbent core 20A.

[0146] As shown in FIG. 14, the liquid absorbent fiber 201 and SAP are bonded to the non-skin side of the core wrap sheet 25, which is located closer to the skin than the absorbent core 20A. The basis weight of the liquid absorbent fiber 201 bonded to the core wrap sheet 25 is 5 g / m 2 More than 90g / m 2 The basis weight of the SAP adhered to the core wrap sheet 25 is 5 g / m or less. 2 More than 90g / m 2 14, the absorbent core 20A has a skin-side portion H1 where the liquid-absorbent fiber 201 and SAP are bonded to the non-skin-side surface of the core wrap sheet 25. Note that the "basis weight of the liquid-absorbent fiber 201 bonded to the core wrap sheet 25" and the "basis weight of the SAP bonded to the core wrap sheet 25" each refer to the basis weight of the portion excluding the low-basis weight region 211.

[0147] Even with a diaper 1 having such an absorbent core 20A, the thickness of the absorbent core 20A can be reduced, thereby reducing the thickness of the diaper 1 and reducing the risk of it being noticeable from the outside of clothing, while still maintaining the body exudation absorption function of a disposable diaper. Furthermore, since the diaper 1 can be made soft, it can be easily adapted to the wearer's body and movements, reducing discomfort to the wearer.

[0148] 14, it is preferable that the liquid-absorbent fiber 201 and SAP are bonded to the non-skin side of the core wrap sheet 25, which is located closer to the skin than the absorbent core 20A, and that the liquid-absorbent fiber 201 and SAP are bonded to the skin side of the core wrap sheet 26, which is located closer to the skin than the absorbent core 20A. It is also preferable that the liquid-absorbent fiber 201 not bonded to either the core wrap sheet 25 or the core wrap sheet 26 accounts for 5% or less by weight of the liquid-absorbent fiber 201 contained in the absorbent core 20A, that the density of the liquid-absorbent fiber 201 bonded to the non-skin side of the core wrap sheet 25 is uniform, and that the density of the SAP bonded to the non-skin side of the core wrap sheet 25 is uniform. 14, the absorbent core 20A has a skin-side portion H1 where the liquid-absorbent fiber 201 and SAP are bonded to the non-skin-side surface of the core wrap sheet 25, a skin-side portion H3 where the liquid-absorbent fiber 201 and SAP are bonded to the skin-side surface of the core wrap sheet 26, and a middle portion H2 that is not bonded to either the core wrap sheet 25 or the core wrap sheet 26. In other words, it is preferable that the densities of the liquid-absorbent fiber 201 and SAP in the skin-side portion H1 are uniform, and that the liquid-absorbent fiber 201 in the middle portion H2 account for 5% or less by weight of the liquid-absorbent fiber 201 in the entire absorbent core 20A.

[0149] Even in a diaper 1 having such an absorbent core 20A, the uniform density of the liquid-absorbent fibers 201 and SAP bonded to the core wrap sheets 25 and 26 allows the thickness of the absorber 20 to be thinner than when the liquid-absorbent fibers 201 and SAP are not uniform, thereby reducing the thickness of the diaper 1 and reducing the risk of it being noticeable from the outside of clothing. Furthermore, the diaper 1 is made soft and facilitates the movement of body waste into the absorbent core 20A, making it easier to fit the wearer's body and movements, reducing discomfort to the wearer and improving the absorbency of the disposable diaper.

[0150] When the absorbent core 20A has multiple absorbent layers, it is preferable that one or more absorbent layers (skin-side layer 21, intermediate layer 22) located away from the skin-side absorbent layer (skin-side upper layer 24) in the thickness direction do not contain nonwoven fabric. In this embodiment, the skin-side layer 21 and the intermediate layer 22 are layers provided with SAP and cellulose fibers (pulp fibers) and do not contain sheet materials such as nonwoven fabric. This reduces the risk of the diaper 1 becoming excessively thick due to absorption of bodily exudates compared to when the absorbent layer located away from the skin-side upper layer 24 contains nonwoven fabric, and reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption. Furthermore, the diaper 1 can be softened even after absorbing bodily exudates, making it easier to fit the wearer's body and reducing discomfort when worn.

[0151] Furthermore, as shown in FIG. 4, when the absorbent core 20A has multiple absorbent layers, it is preferable that the absorbent layer (skin-side upper layer 24) closest to the wearer's body in the thickness direction does not contain absorbent resin powder. In this embodiment, the skin-side upper layer 24 is formed solely from liquid-absorbent fibers 201 made of cellulose fibers (pulp fibers). The absence of absorbent resin powder such as SAP in the skin-side upper layer 24 reduces the risk of localized thickness increases due to the absorption of bodily waste and reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption. Furthermore, the diaper 1 can be made soft even after absorbing bodily waste, making it easier to fit the wearer's body and reducing discomfort when worn.

[0152] In the diaper 1 of the above-described embodiment, the absorbent core 20A includes the skin-side upper layer 24 closest to the skin. However, the skin-side layer 21 may be the layer of the absorbent core 20A closest to the skin in the thickness direction without including the skin-side upper layer 24. That is, the skin-side layer 21 may be the absorbent layer of the absorbent core 20A that is closest to the skin in the thickness direction. In such a case, when the skin-side layer 21 includes a superabsorbent polymer (water-absorbent polymer) and is the layer of the absorbent core 20A closest to the skin in the thickness direction, it is preferable that the superabsorbent polymer (water-absorbent polymer, water-absorbent resin powder) provided in the skin-side layer 21 has a liquid permeation rate under load of more than 10 seconds. This reduces the risk of localized thickness increases due to the absorption of bodily exudates and reduces the risk of the diaper 1 being noticeable from the outside of clothing after absorption, compared to when the liquid permeation rate under load of the skin-side layer 21 is 10 seconds or less. Furthermore, the diaper 1 can be softened even after absorbing bodily waste, making it easier to fit the wearer's body and reducing discomfort when worn.

[0153] ===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 the present invention includes equivalents thereof.

[0154] In the above-described embodiment, the non-skinside layer 23 illustrated in FIG. 5 has a shorter longitudinal length than the skinside layer 21 and the intermediate layer 22. However, this is not limited thereto. The longitudinal lengths may be the same. Alternatively, the longitudinal length of the non-skinside layer 23 may be longer than the skinside layer 21 and the intermediate layer 22, and the rear end (rear end) of the non-skinside layer 23 may be located outside (rear side) of the rear ends (rear ends) of the skinside layer 21 and the intermediate layer 22. Conversely, the longitudinal length of the rear end (rear side) of the non-skinside layer 23 may be even shorter than that of the present embodiment. In this case, material can be reduced, and the rigidity of the rear-side absorbent core is reduced, resulting in increased flexibility. Furthermore, because the rear-side region is located away from the wearer's urinary excretion opening, even if the longitudinal length of the non-skinside layer 23 is short, leakage of excreted fluid is unlikely to occur.

[0155] In the above-described embodiment, as shown in Fig. 4, an adhesive and an intermediate sheet 27 are provided between the intermediate layer 22 and the non-skin side layer 23, but this is not limited thereto. 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 or the intermediate sheet 27 or both. This prevents the adhesive 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.

[0156] In the above-described embodiment, the skin-side layer 22 and the non-skin-side layer 23 are integrally formed. However, the intermediate layer 22 and the non-skin-side layer 23 may also be integrally formed. In this case, an adhesive or a sheet such as a nonwoven fabric may or may not be interposed between the intermediate layer 22 and the skin-side layer 21. In this case, the skin-side layer 21 may be an SAP layer composed only of SAP, or may be a layer composed of SAP and liquid-absorbent fibers. However, it is preferable that the average value of the total area occupied by SAP per unit area in a cross section taken along the thickness direction of the skin-side layer 21 is 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-skin-side layer 23. This allows the SAP of the skin-side layer 21 to suppress rewet.

[0157] Furthermore, even when the intermediate layer 22 and the non-skin side layer 23 are integrated, it is desirable that the SAP of the skin side layer 21 have a liquid absorption rate, as measured by the vortex method, that is slower than the SAP of the non-skin side layer 23. This makes it easier for the excrement to diffuse in the plane direction or toward the non-skin side rather than being absorbed by the skin side layer 21, making it easier to diffuse the excrement throughout the absorbent core 20A, reducing the likelihood of the excrement being retained only in localized areas of the skin side layer 21 and reducing the risk of localized swelling of the absorbent core 20A.

[0158] Furthermore, even when the intermediate layer 22 and the non-skinside layer 23 are integrated, it is preferable that the total water retention capacity of the superabsorbent polymer present in the skinside layer 21 is less than the total water retention capacity of the superabsorbent polymer present in the non-skinside layer 23. This makes it easier for the non-skinside layer 23 in the absorbent core 20A to retain excrement (liquid) than the skinside layer 21, thereby reducing the risk of the absorbent core 20A swelling locally at the portion where excrement is received on the skin side of the absorbent core 20A during wear, and also reducing the risk of the local swelling of the diaper 1 after absorption being noticeable from the outside of clothing.

[0159] In the above-described embodiment, the absorbent core 20A is formed of the skin-side upper layer 24, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 as shown in Fig. 4, but the absorbent cores 21-23 (absorbent cores 21-24) are not limited to this. The absorbent core 20A may be configured to contain cellulose fibers and SAP. For example, the absorbent core 20A may be configured to have three layers without the skin-side upper layer 24. Alternatively, the absorbent core 20A may be configured to have two layers in total: one layer containing a mixture of SAP and cellulose fibers, and one layer made of an SAP sheet. The absorbent core 20A may be configured to have a single layer containing cellulose fibers and a superabsorbent polymer.

[0160] In the above-described embodiment, three layers, namely, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23 (four layers, namely, the skin-side upper layer 24, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23) are laminated over substantially the entire absorbent cores 21-23 (absorbent cores 21-24). However, this is not limitative and three layers (21-23) or four layers (21-24) may be laminated at any location. Preferably, the three layers (21-23) or four layers (21-24) are laminated at and near the position where the wearer's urinary excretion opening contacts when the diaper 1 is worn. Similarly, the low basis weight regions 211, 221 of the skin-side layer 21 and the intermediate layer 22 and the low basis weight region 231 of the non-skin-side layer 23 may also be provided at and near the position where the wearer's urinary excretion opening contacts. This allows the excreted liquid to be quickly drawn to the inner side of the absorbent cores 21-23 at positions that directly receive a large amount of excreted liquid during excretion.

[0161] In the above-described embodiment, the skin side layer 21 and the intermediate layer 22 are integrally formed, but this is not limiting, and the skin side layer 21 and the intermediate layer 22 do not have to be integrally formed. For example, an adhesive or a nonwoven fabric may be disposed between the skin side layer 21 and the intermediate layer 22. The adhesive can better fix the SAP contained in the skin side layer 21, and the nonwoven fabric can further diffuse excreted liquid in the planar direction on the nonwoven fabric. [Explanation of symbols]

[0162] 1. Diapers (pants-type disposable diapers, absorbent articles) 2 side joints, 3 Leakage prevention wall section, 10. Absorbent body; 12 Top sheet (surface sheet), 13 Back sheet (rear sheet), 13a Back sheet (liquid-impermeable sheet, back sheet), 13b Back sheet (exterior sheet, back sheet), 15 side seats, 16 Leak-proof wall elastic member, 17 Leg gather elastic member, 20 absorber, 20A absorbent core, 201 Liquid absorbent fibers (cellulose fibers), SAP Super Absorbent Polymer, 21 skin side layer (absorbent core), 211 low basis weight region, 22 intermediate layer (absorbent core), 221 low basis weight region, 23 Non-skin side layer (absorbent core), 231 Low basis weight region, 24 Upper layer facing the skin (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 fabric (intermediate sheet), 30 Front waistband, 31 skin side sheet, 32 non-skin side sheet, 33 waist elastic member, 34 cover sheets, 40 rear waistband, 41 skin side sheet, 42 non-skin side sheet, 43 waist elastic member; 44 cover sheets, 50 punctate compression areas, F fold

Claims

1. In the unfolded state, the bag has a longitudinal direction, a width direction, and a thickness direction which are perpendicular to each other, An absorbent article comprising an absorbent core, the absorbent core comprises cellulose fibers and a superabsorbent polymer; The absorbent core has a low basis weight portion along the longitudinal direction, the low basis weight portion having a lower basis weight than the surrounding area, When the absorbent article is folded in half at the center fold in the longitudinal direction, the bottom area is 150 cm ２ a weight having a weight of 5 kg is placed on the absorbent article for 24 hours, and then the weight is removed from the absorbent article, the thickness of the folded portion at the center in the width direction is 6.5 mm or less, After removing the weight, 40 ml of artificial urine was dropped onto the skin side of the absorbent article in the unfolded and stretched state, at a position 50 mm forward of the center in the longitudinal direction and at the center in the width direction, over a period of 5 seconds, three times. In the absorbed state after the artificial urine had been absorbed, The thickness of the folded portion of the absorbent article at the center in the width direction is 20.3 mm or less, and, In a torsion test in which the absorbent article folded in half is gripped at the center portions in the longitudinal direction of both end portions in the width direction and twisted around an imaginary axis along the width direction, and the absorbent article folded in half is gripped at the center portions in the width direction of both end portions in the longitudinal direction and twisted around an imaginary axis along the longitudinal direction, the torque value of the absorbent article is 44.1 mN m or less. An absorbent article characterized by:

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

3. The absorbent article according to claim 1 or 2, An absorbent article characterized in that the liquid absorption rate of the superabsorbent polymer measured by the vortex method is 40 seconds or more.

4. The absorbent article according to claim 1 or 2, An absorbent article characterized in that the core wrap sheet provided on at least one of the skin side and non-skin side of the absorbent core is a hydrophilic nonwoven fabric.

5. The 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; the cellulose fibers and the superabsorbent polymer are bonded to the non-skin side of the skin-side core wrap sheet portion; The basis weight of the cellulose fibers bonded to the skin side core wrap sheet portion is 5 g / m ２ Above, 90g / m ２ is as follows: The basis weight of the superabsorbent polymer adhered to the skin side core wrap sheet portion is 5 g / m ２ Above, 160g / m ２ An absorbent article characterized by the following:

6. The 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-facing core wrap sheet portion that covers at least a portion of the non-skin-facing side of the absorbent core; and the cellulose fibers and the superabsorbent polymer are bonded to the non-skin side of the skin-side core wrap sheet portion; the cellulose fibers and the superabsorbent polymer are bonded to the skin side of the non-skin side core wrap sheet portion; the cellulose fibers not bonded to either the skin-side core wrap sheet portion or the non-skin-side core wrap sheet portion account for 5% or less by weight of the cellulose fibers; The density of the cellulose fibers bonded to the non-skin side of the skin side core wrap sheet portion is uniform, An absorbent article characterized in that the density of the superabsorbent polymer adhered to the non-skin side of the skin-side core wrap sheet portion is uniform.

7. The absorbent article according to claim 1 or 2, the absorbent core having a plurality of absorbent layers; the plurality of absorbent layers includes a first absorbent layer and a second absorbent layer; the low basis weight portion includes a first low basis weight portion provided in the first absorbent layer and a second low basis weight portion provided in the second absorbent layer, An absorbent article comprising a portion where the first low basis weight portion and the second low basis weight portion overlap when viewed in the thickness direction.

8. The 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 provided closest to the skin among the plurality of absorbent layers; An absorbent article characterized by having an intermediate sheet between the absorbent layer provided on the skin side of the SAP layer and the absorbent layer.

9. The absorbent article according to claim 1 or 2, the absorbent core having a plurality of absorbent layers; the plurality of absorbent layers includes a first absorbent layer and a second absorbent layer; An absorbent article characterized in that, on one side in the width direction, a side end of the first absorbent layer and a side end of the second absorbent layer are provided at different positions.

10. The absorbent article according to claim 1 or 2, the absorbent core having a plurality of absorbent layers; the plurality of absorbent layers includes a first absorbent layer and a second absorbent layer; An absorbent article, characterized in that one end of the first absorbent layer in the longitudinal direction and one end of the second absorbent layer in the longitudinal direction are provided at different positions.

11. The absorbent article according to claim 1 or 2, The absorbent core comprises: a skin side layer having a first thickness, and a volume occupied by the superabsorbent polymer being greater than a volume occupied by the cellulose fibers; an intermediate layer having a second thickness, the intermediate layer having a volume occupied by the cellulose fibers greater than a volume occupied by the superabsorbent polymer; a non-skin side layer having a third thickness and in which the volume occupied by the superabsorbent polymer is greater than the volume occupied by the cellulose fibers, the intermediate layer is located closer to the skin than the skin side layer in the thickness direction, The absorbent article is characterized in that the non-skin side layer is located closer to the skin side in the thickness direction than the intermediate layer.

12. The absorbent article of claim 11, An absorbent article characterized in that the superabsorbent polymer contained in the skin-side layer has a liquid absorption rate measured by a vortex method slower than the superabsorbent polymer contained in the non-skin-side layer.

13. The absorbent article of claim 11, the average value of the total area occupied by the superabsorbent polymer per unit area in the cross section of the skin side layer along the thickness direction is An absorbent article characterized in that the average value of the total area occupied by the superabsorbent polymer per unit area in a cross section of the non-skin side layer taken along the thickness direction is larger than the average value of the total area occupied by the superabsorbent polymer per unit area.

14. The absorbent article of claim 11, An absorbent article characterized in that the total water retention capacity of the superabsorbent polymer present in the skin-side layer is less than the total water retention capacity of the superabsorbent polymer present in the non-skin-side layer.

15. The 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-facing core wrap sheet portion that covers at least a portion of the non-skin-facing side 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, An absorbent article characterized by having a portion where the top sheet and the back sheet are adhered to each other.

16. The absorbent article according to claim 1 or 2, The density of the absorbent core is 0.2 g / cm ３ An absorbent article characterized by the above.

17. The 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 surface sheet provided on the skin side of the skin side core wrap sheet portion, An absorbent article characterized in that the density of the absorbent core is higher than the density of the top sheet.

18. The absorbent article of claim 11, the absorbent core has a plurality of absorbent layers including the skinside layer, the intermediate layer, and the non-skinside layer; An absorbent article characterized in that, among the plurality of absorbent layers, one or more absorbent layers located closer to the non-skin side than the absorbent layer located closest to the skin side in the thickness direction do not contain nonwoven fabric.

19. The absorbent article of claim 11, the absorbent core has a plurality of absorbent layers including the skinside layer, the intermediate layer, and the non-skinside layer; An absorbent article, wherein the absorbent layer located closest to the skin in the thickness direction among the plurality of absorbent layers does not contain absorbent resin powder.

20. The absorbent article of claim 11, the absorbent core has a plurality of absorbent layers including the skinside layer, the intermediate layer, and the non-skinside layer; Among the plurality of absorbent layers, the absorbent layer located closest to the skin in the thickness direction comprises the superabsorbent polymer, An absorbent article characterized in that the liquid permeation rate under load of the superabsorbent polymer in the absorbent layer located closest to the skin exceeds 10 seconds.

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