Absorbent article

Abstract

The present invention provides an absorbent article comprising an absorbent body that includes an absorbent core and a plurality of sheet parts, wherein: the absorbent core includes a highly absorbent polymer; the plurality of sheet parts are composed of at least one of cellulose fibers and thermoplastic fibers having an average fiber diameter of 16.8 μm or less; the absorbent body includes a first adhesive layer, a second adhesive layer, and an interposing absorption layer; the first adhesive layer and the second adhesive layer are two adhesive layers that, among the adhesive layers, have the greatest thickness when the interposing absorption layer is in a natural state and that are adjacent to each other in the thickness direction; said absorbent article includes an absorption layer differing from the interposing absorption layer on at least one of a side which is further outward than the first adhesive layer in the thickness direction and a side which is further outward than the second adhesive layer in the thickness direction; and when a weight having a bottom area of 150 cm2 and weighing 5 kg is placed on said absorbent article for 24 hours with the absorbent article being folded in half and is then subsequently removed, the average thickness of the interposing absorption layer immediately after the removal of the weight is 2.0 mm or less, and the value obtained by dividing the thickness after 72 hours by the thickness immediately after the removal of the weight is 106.6% or less.

Description

absorbent articles

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

[0002] Conventionally, there are absorbent articles such as disposable diapers that include a liquid-absorbing absorbent body. Since absorbent articles usually have a thick absorbent body, there is known an absorbent product in which the thickness of the absorbent article is compressed and the absorbent article is packaged in a compact form in order to improve the efficiency of distribution, sales, storage, etc., as described in Patent Document 1.

[0003] Special Publication No. 2013-505796

[0004] However, the absorbent product described in Patent Document 1 is compressed to a reduced thickness when contained in a package, but once the package is opened or the absorbent article is removed from the package, the absorbent article regains its original thickness. As the absorbent article becomes thicker, it becomes bulky, making it difficult to carry and store. For example, in the case of disposable diapers for infants, the thicker the disposable diapers a mother carries, the more limited the number of disposable diapers she can fit in her bag. This reduces the number of disposable diapers she carries, which limits the number of diaper changes and increases the number of times disposable diapers need to be refilled, creating inconvenience. Therefore, there is a demand for an absorbent article that does not increase in bulk (thickness) even after being removed from the package.

[0005] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an absorbent article that can easily reduce the risk of the absorbent article becoming bulky.

[0006] The main invention for achieving the above object is an absorbent article having an absorbent body which, in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction which are orthogonal to one another, and which comprises an absorbent core and a plurality of sheet portions including a skin-side core wrap sheet portion located closer to the skin than the absorbent core and a non-skin-side core wrap sheet portion located closer to the skin than the absorbent core, wherein the absorbent core comprises at least a superabsorbent polymer, and each of the plurality of sheet portions is made of at least one of cellulose fiber and thermoplastic fiber having an average fiber diameter of 16.8 μm or less, and the absorbent body comprises a first adhesive layer, and a second adhesive layer adjacent to the first adhesive layer in the thickness direction, and an intervening absorbent layer sandwiched between the first adhesive layer and the second adhesive layer and consisting of one or more absorbent layers, the first adhesive layer and the second adhesive layer being two adhesive layers adjacent to each other in the thickness direction among a plurality of adhesive layers provided on the absorbent body, such that the thickness of the intervening absorbent layer in its natural state is greatest, and an absorbent layer different from the intervening absorbent layer is provided on at least one of the outer sides of the first adhesive layer in the thickness direction and the outer sides of the second adhesive layer in the thickness direction, and the absorbent article has a base area of ​​150 cm when folded in half at a fold in the center in the longitudinal direction. ２ and a 5 kg weight placed on the absorbent article for 24 hours, after which the weight is removed, the average thickness of the intervening absorbent layer immediately after the weight is removed is 2.0 mm or less, and the thickness at the center of the width direction of the folded portion immediately after the weight is removed is defined as an immediate thickness, and the thickness at the center of the width direction of the folded portion 72 hours after the weight is removed is defined as a 72-hour thickness, and the value obtained by dividing the 72-hour thickness by the immediate thickness is 106.6% or less. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0007] According to the present invention, an absorbent article can be obtained that is likely to be increased in bulk.

[0008] 6A is a schematic perspective view of the diaper 1; FIG. 6B is a plan view of the diaper 1 in an unfolded and stretched state, viewed from the skin side; FIG. 6C is a schematic cross-sectional view taken along the center line CL of FIG. 2; FIG. 6D is a schematic cross-sectional view of the absorbent body 20 of this embodiment; FIG. 6E is a plan view of the absorbent cores 21-23 superimposed on each other; FIG. 6A is a plan view of the skin side layer 21 and the intermediate layer 22, and FIG. 6B is a plan view of the non-skin side layer 23; FIG. 6F is a diagram illustrating the state in which a weight W is placed on the diaper 1; FIG. 6G is a diagram illustrating the measurement of the fold F; FIG. 6H is a diagram illustrating the measurement results of the diaper 1 and products A, B, and C; FIG. 6I is a schematic cross-sectional view of the absorbent body 20 of this embodiment; FIG. 6I is a schematic plan view of the absorbent body 20, viewed from the skin side; FIG. 6I is a plan view illustrating the region in the core wrap sheet 26 where SAP particles and adhesive are provided; FIG. 6I is a photograph of a portion of the skin side of the core wrap sheet 26 in the inner region IR, magnified 40 times; FIG. 6I is a photograph of a portion of the skin side of the core wrap sheet 26 in the outer region OR, magnified 40 times. 15A and 15B are explanatory diagrams for the "torsion test." It is a cross-sectional schematic diagram of a modified example of the absorbent body.

[0009] The present specification and the accompanying drawings make clear at least the following: (Aspect 1) An absorbent article having an absorbent body that, in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction that are orthogonal to one another, and that includes an absorbent core and a plurality of sheet portions including a skin-side core wrap sheet portion located closer to the skin than the absorbent core and a non-skin-side core wrap sheet portion located closer to the skin than the absorbent core, wherein the absorbent core comprises at least a superabsorbent polymer, and each of the plurality of sheet portions is made of at least one of cellulose fiber and thermoplastic fiber having an average fiber diameter of 16.8 μm or less, and the absorbent body has a first adhesive layer, a first adhesive layer, and a second adhesive layer adjacent to the first adhesive layer in the thickness direction. and an intervening absorbent layer sandwiched between the first adhesive layer and the second adhesive layer and consisting of one or more absorbent layers, the first adhesive layer and the second adhesive layer being two adhesive layers adjacent to each other in the thickness direction among the plurality of adhesive layers provided on the absorbent body, at which the thickness of the intervening absorbent layer in its natural state is greatest, and an absorbent layer different from the intervening absorbent layer is provided on at least one of the outer sides of the first adhesive layer in the thickness direction and the outer sides of the second adhesive layer in the thickness direction, and the absorbent article has a base area of ​​150 cm when folded in half at the center fold in the longitudinal direction. ２ and a weight having a weight of 5 kg is placed on the absorbent article for 24 hours, and then the weight is removed. Immediately after the weight is removed, the average thickness of the intervening absorbent layer is 2.0 mm or less, and when the thickness at the center in the width direction of the folded portion immediately after the weight is removed is defined as the immediate thickness and the thickness at the center in the width direction of the folded portion 72 hours after the weight is removed is defined as the 72-hour thickness, the value obtained by dividing the 72-hour thickness by the immediate thickness is 106.6% or less.

[0010] According to Aspect 1, when the value obtained by dividing the thickness after 72 hours by the thickness immediately after is 106.6% or less, the absorbent body having multiple absorbent layers can provide liquid absorbency through the superabsorbent polymer and fibers, while reducing the risk of the absorbent article becoming bulky due to the highly flexible fibers and multiple adhesive layers, compared to when the value obtained by dividing the thickness after 72 hours by the thickness immediately after is greater than 106.6%. This makes it easier to store and carry the absorbent article.

[0011] (Aspect 2) The absorbent article of Aspect 1, wherein when the thickness of the absorbent article from which the weight has been removed is the thickness at the center of the width direction of the folded portion one week after the weight has been removed, the value obtained by dividing the thickness one week later by the thickness immediately after the weight has been removed is 112.2% or less.

[0012] According to aspect 2, the absorbent body having multiple absorbent layers is provided with liquid absorbency through the superabsorbent polymer and fibers, while the highly flexible fibers and multiple adhesive layers make it easier to reduce the risk of the absorbent article becoming bulky, compared to when the value obtained by dividing the thickness one week later by the thickness immediately afterwards is greater than 112.2%.

[0013] (Aspect 3) The absorbent article of aspect 1 or 2, wherein the absorbent core has a low basis weight portion along the longitudinal direction, the low basis weight portion having a basis weight lower than that of the surrounding area.

[0014] According to aspect 3, in the low basis weight portion, each of the plurality of sheet portions can easily approach the absorbent core and be easily adhered to it, which helps to reduce the risk of the absorbent core becoming bulky.

[0015] (Aspect 4) An absorbent article according to any one of aspects 1 to 3, characterized in that the absorbent layer has a first absorbent layer located closest to the skin in the thickness direction and a second absorbent layer located further away from the skin than the first absorbent layer, and on one side in the width direction of the crotch area that is located under the wearer's crotch when worn, the side end of the second absorbent layer is located outside the side end of the first absorbent layer, and has a portion where the skin-side core wrap sheet portion and the skin-side surface of the second absorbent layer are adhered.

[0016] According to the fourth aspect, the absorbent core has a portion bonded to the skin-side core wrap sheet portion, which helps to reduce the risk of the bulk of the absorbent core increasing toward the skin side.

[0017] (Aspect 5) An absorbent article according to any one of Aspects 1 to 4, characterized in that the absorbent layer has a first absorbent layer located on the outermost side in the thickness direction and a second absorbent layer located on the other side of the first absorbent layer, and on one side in the longitudinal direction, the end on one side of the longitudinal direction of the second absorbent layer is located outside the end on one side of the longitudinal direction of the first absorbent layer, and has a portion where the other side surface in the thickness direction of the sheet portion located on one side in the thickness direction of the first absorbent layer is adhered to the one side surface in the thickness direction of the second absorbent layer.

[0018] According to aspect 5, the absorbent core has a portion bonded to the sheet portion, which helps to reduce the risk of the absorbent core becoming bulky.

[0019] (Aspect 6) An absorbent article according to any one of aspects 1 to 5, characterized in that, when viewed in the thickness direction, there is a portion inside the outer contour of the absorbent core where the non-skin side of the skin-side core wrap sheet portion and the skin side of the non-skin side core wrap sheet portion are adhered.

[0020] According to the sixth aspect, the skin-side core wrap sheet portion and the non-skin-side core wrap sheet portion are bonded to each other, which helps to reduce the risk of the absorbent core becoming bulky.

[0021] (Aspect 7) An absorbent article according to any one of aspects 1 to 6, characterized in that in the crotch area, which is located under the wearer's crotch when worn, the absorbent core has a constricted portion on the inside in the width direction, and when viewed in the thickness direction, has a portion in an adjacent area adjacent to the constricted portion from the outside in the width direction where the non-skin side of the skin-side core wrap sheet portion and the skin side of the non-skin-side core wrap sheet portion are adhered.

[0022] According to aspect 7, by having portions where the adjacent regions and the core wrap sheet portions are bonded together in the thickness direction, it becomes easier to reduce the risk of the absorbent core becoming bulky.

[0023] (Aspect 8) An absorbent article according to any one of Aspects 1 to 7, characterized in that a strip of adhesive is provided on the other surface of the sheet portion in the thickness direction, the average width of the strip of adhesive being smaller than the average particle size of the superabsorbent polymer, and when an area of ​​the other surface of the sheet portion that is located outside the outermost ends of the plurality of absorbent layers in the width direction is defined as an outer region, and an area of ​​the other surface of the sheet portion that is located inside the outermost ends of the plurality of absorbent layers in the width direction is defined as an inner region, the number of intersections of the strip of adhesive per unit area in the inner region is greater than the number of intersections of the strip of adhesive per unit area in the outer region.

[0024] According to the eighth aspect, the more adhesive there is in the sheet portion in contact with the absorbent layer, the easier it is to reduce the risk of the sheet portion increasing the bulk of the absorbent core.

[0025] (Aspect 9) The absorbent article of any one of Aspects 1 to 8, wherein the sheet portion has an intermediate sheet between a plurality of the absorbent layers adjacent to each other in the thickness direction, the intermediate sheet being formed of at least one of cellulose fiber and thermoplastic fiber having an average fiber diameter of 16.8 μm or less, and the intermediate sheet has an intermediate adhesive layer provided with adhesive on at least one surface in the thickness direction.

[0026] According to aspect 9, the intermediate sheet and adhesive provided between multiple absorbent layers makes it easier to restrict the movement of superabsorbent polymers and fibers between each absorbent layer, thereby making it easier to reduce the risk of the absorbent core becoming bulky.

[0027] (Aspect 10) The absorbent article of Aspect 9, wherein the skin side core wrap sheet portion or the non-skin side core wrap sheet portion has a portion bonded to the intermediate sheet.

[0028] According to aspect 10, the risk of the absorbent core located between the core wrap sheet portion and the intermediate sheet increasing in bulk can be reduced.

[0029] (Aspect 11) The absorbent article according to any one of aspects 1 to 10, wherein the absorbent body has compressed portions compressed in the thickness direction.

[0030] According to Aspect 11, the compressed portions are portions that are high in density and thin in thickness, and thus by providing the absorbent body with compressed portions, it is possible to reduce the risk of the absorbent body becoming bulky.

[0031] (Aspect 12) The absorbent article of any one of Aspects 1 to 11, wherein the longitudinal length of the absorbent article in the folded state is 85.3% or more of half the longitudinal length of the absorbent article in the unfolded and stretched state.

[0032] According to aspect 12, the risk of gaps occurring within the absorbent core due to shrinking and deforming the absorbent body in the longitudinal direction is reduced, thereby reducing the risk of the absorbent core becoming bulky.

[0033] (Aspect 13) The absorbent article of any one of aspects 1 to 12, wherein there is no elastic member that continuously traverses the absorbent core in the width direction from one end to the other end in the width direction of the absorbent core.

[0034] According to aspect 13, the risk of gaps occurring within the absorbent core due to shrinking and deforming the absorbent body in the width direction is reduced, thereby reducing the risk of the absorbent core becoming bulky.

[0035] (Aspect 14) An absorbent article according to any one of aspects 1 to 13, characterized in that it has a top sheet provided on the skin side of the skin-side core wrap sheet portion and a back sheet provided on the non-skin side of the non-skin-side core wrap sheet portion, and has a portion where the top sheet and the back sheet are adhered.

[0036] According to Aspect 14, the absorbent body is sandwiched between the top sheet and the back sheet, thereby reducing the risk of the absorbent body becoming bulky.

[0037] (Aspect 15) The absorbent article of any one of aspects 1 to 14, wherein the absorbent layer has an SAP layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers.

[0038] According to Aspect 15, the superabsorbent polymer is a material that does not easily increase in bulk before absorbing moisture, which makes it easier to reduce the risk of the absorbent core increasing in bulk.

[0039] (Aspect 16) The absorbent article of any one of Aspects 1 to 15, wherein the absorbent layer comprises cellulose fibers, and the absorbent layer has a pulp layer in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer.

[0040] According to Aspect 16, it is possible to reduce the risk that the absorbent core will become excessively bulky even in the presence of moisture.

[0041] (Aspect 17) The absorbent article of any one of Aspects 1 to 16, wherein the absorbent layer comprises cellulose fibers, and the absorbent layer has an SAP layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers, and a pulp layer in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer, and the average thickness of the pulp layer is 1.5 times or less the average thickness of the SAP layer.

[0042] According to aspect 17, the amount of cellulose fiber in the absorbent layer can be reduced compared to when the thickness of the pulp layer is made thicker than 1.5 times the thickness of the SAP layer, which makes it easier to reduce the risk of the absorbent core becoming bulky.

[0043] (Aspect 18) The absorbent article of any one of Aspects 1 to 17, wherein the absorbent layer comprises cellulose fibers, and the absorbent layer has an SAP layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers, and a pulp layer in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer, the SAP layer and the pulp layer being adjacent in the thickness direction, and an adhesive being provided between the SAP layer and the pulp layer.

[0044] According to Aspect 18, since the superabsorbent polymer of the SAP layer is a material that does not easily recover its bulk, the use of the SAP layer improves the absorption function while reducing the risk of the absorbent core becoming bulky. Furthermore, by using the adjacent SAP layer and pulp layer, the thickness of the relatively hard, uneven SAP layer is buffered by the relatively soft pulp layer, and the SAP layer and pulp layer are fixed together with an adhesive, which suppresses the movement of the fibers in the pulp layer, reducing the risk of voids being generated in the cellulose fibers of the pulp layer and reducing the risk of the absorbent core becoming bulky.

[0045] (Aspect 19) The absorbent article of any one of Aspects 1 to 18, wherein the thermoplastic fibers are polyethylene fibers, polypropylene fibers, or fibers made of a combination of the polyethylene fibers and the polypropylene fibers.

[0046] According to Aspect 19, polyethylene fibers and polypropylene fibers are soft fibers, and they make the absorbent body softer than when polyethylene terephthalate fibers are used, while also reducing the risk of the absorbent body becoming bulky.

[0047] (Aspect 20) The absorbent core comprises cellulose fibers, and the density of the absorbent core is 0.2 g / cm ３ 19. The absorbent article according to any one of Aspects 1 to 19, characterized in that:

[0048] According to aspect 20, the density of the absorbent core is 0.2 g / cm ３ Since the gaps inside the absorbent core can be made smaller than when the absorbent core is smaller, the absorbent core is less likely to be compressed and less likely to recover its bulk.

[0049] (Aspect 21) The absorbent article of any one of Aspects 1 to 20, wherein one or more of the intervening absorbent layers that are located closer to the skin than the absorbent layer that is closest to the skin in the thickness direction do not include a nonwoven fabric.

[0050] According to Aspect 21, the risk of the absorbent body increasing in bulk can be reduced, making it easier to store and carry the absorbent article.

[0051] (Aspect 22) The absorbent article of any one of aspects 1 to 21, wherein the absorbent layer located closest to the skin in the thickness direction of the intervening absorbent layers does not contain absorbent resin powder.

[0052] According to Aspect 22, the risk of the absorbent body becoming bulky is easily reduced, and the absorbent article becomes easier to store and carry.

[0053] (Aspect 23) The absorbent article of any one of Aspects 1 to 22, wherein the intervening absorbent layer, the absorbent layer closest to the skin in the thickness direction, comprises the superabsorbent polymer, and the superabsorbent polymer in the absorbent layer closest to the skin has a liquid permeation rate under load of more than 10 seconds.

[0054] According to Aspect 23, while the absorbent article has the absorption function, the risk of the absorbent article increasing in bulk is reduced, making it easier to store and carry the absorbent article.

[0055] Embodiments The absorbent article according to the present invention will be described using a pants-type disposable diaper 1 for infants (hereinafter also referred to as "diaper 1") as an example. 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, an animal, or other living being.

[0056] <Configuration of Diaper 1> Fig. 1 is a schematic perspective view of the 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-circumference sections 30, 40, etc., described below) are stretched to the extent that they match or are close to the dimensions of the individual components. The "unfolded state" of the diaper 1 refers to a state in which the diaper 1 is opened and unfolded in a plane by separating a pair of side seam sections 2 provided on both sides of the diaper 1.

[0057] 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 abdomen side, and the rear side corresponds to the wearer's back 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.

[0058] 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 other covering the wearer's dorsal region is also referred to as the rear waist-surrounding section 40.

[0059] 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 C-C 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 being joined and fixed to the skin side of the nearest waistband 30, 40, resulting in a generally H-shaped external shape in a plan view. Then, from this state, the absorbent main body 10 is folded in half at a fold 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 in the width direction to form a pair of side joint portions 2. The side joint portions 2 are formed by known joining means such as welding or adhesive.

[0060] The absorbent 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 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.

[0061] The absorbent main body 10 is provided with a pair of leakage preventing walls 3 on both sides in the width direction along the longitudinal direction of the absorbent main body 10. In FIG. 3 , a leakage preventing wall elastic member 16 such as rubber thread is attached between the folded side sheets 15 in a stretched state along the longitudinal direction of the absorbent main body 10. This allows the leakage preventing walls 3 to stand up against the skin side. However, this is not limited to the above. The pair of leakage preventing walls may be formed by folding a portion of the outer sheet 13b against 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 preventing 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 exterior 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.

[0062] 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, a cover sheet 34, 44 may be provided to cover the upper end of the absorbent main body 10 from the skin side. The cover sheet 34, 44 can prevent the absorbent main body 10 from opening.

[0063] 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.

[0064] 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.

[0065] Regarding the absorbent body 20: Fig. 4 is a schematic cross-sectional view 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.

[0066] 4, the absorbent body 20 has a plurality of sheet portions including a core wrap sheet 25 (skin-side core wrap sheet portion 25) located closer to the skin than the absorbent core 20A, and a core wrap sheet 26 (non-skin-side core wrap sheet portion 26) located closer to the skin than the absorbent core 20A. In this embodiment, the plurality of sheet portions include the core wrap sheet 25, the core wrap sheet 26, and an intermediate sheet 27 (hereinafter also referred to as "nonwoven fabric sheet 27"). The absorbent core 20A is located between the skin-side core wrap sheet (skin-side core wrap sheet portion) 25 and the non-skin-side core wrap sheet (non-skin-side core wrap sheet portion) 26.

[0067] 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.

[0068] 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. Hydrophilic nonwoven fabrics are thin and flexible materials that exhibit high drapeability after absorbing bodily waste (liquid). Therefore, when the diaper 1 is worn, the hydrophilic nonwoven fabric 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 bodily waste.

[0069] 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 SAP. The non-skin-side layer 23 is a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fibers 201.

[0070] Furthermore, the absorbent core 20A of the absorbent body 20 of this embodiment further includes a skin-side upper layer (absorbent core) 24, which is located closer to the skin in the thickness direction than the skin-side layer 21 and has a fourth thickness t4 that is thinner than the first thickness t1 of the skin-side layer 21. The skin-side upper layer 24 is a layer in which the volume occupied by the liquid-absorbent fibers 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 fibers 201.

[0071] 4, in this embodiment, the skin side layer 21 and the intermediate layer 22 are integrally formed, and therefore the volume occupancy of the SAP decreases and the volume occupancy of the 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 the liquid-absorbent fiber 201 into a forming mold (recess) that corresponds to the shape of the absorbent core and is provided on the outer peripheral surface of a rotating drum.

[0072] 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.

[0073] Furthermore, in this embodiment, the non-skin side layer 23 is not formed integrally with the intermediate layer 22, but is laminated adjacent to the intermediate layer 22 in the thickness direction via the nonwoven fabric 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.

[0074] The skin side layer 21 and the intermediate layer 22 shown in Fig. 6A are integrally formed and have the same planar shape. The skin side layer 21 and the 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 the intermediate layer 22 are divided into thirds along their maximum longitudinal length, and the center region is defined as the center in the longitudinal direction, where at least a portion of the constricted portions 212, 222 may be located.

[0075] 6B has three longitudinally elongated rectangular divided regions 23a to 23c. The three divided regions 23a to 23c are arranged side by side at intervals in the width direction. Two regions between the three divided regions 23a to 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.

[0076] Absorbent articles, such as disposable diapers, are generally stored in a compressed state in packages during sales and distribution. However, when the package is opened or the absorbent article is removed, the bulk (thickness) of the absorbent article recovers. When the absorbent article regains its bulk, it requires more storage space and becomes bulky when carried. For example, in the case of disposable diapers for infants, the bulkier the disposable diaper, the more bulky it becomes in a parent's bag. This causes inconveniences such as reducing the number of disposable diapers carried and requiring frequent refills of disposable diapers in the bag. On the other hand, the thinner the absorbent article, the harder the absorber becomes and the less absorbent material in the absorbent core that absorbs and retains liquid tends to be, leading to concerns that the absorbent function of the absorbent article will be reduced.

[0077] As described above, the diaper 1 includes an absorbent body 20 including at least a superabsorbent polymer (SAP) and multiple sheet portions including a core wrap sheet 25 and a core wrap sheet 26. Each of the multiple sheet portions is composed of at least one of cellulose fibers and thermoplastic fibers having an average fiber diameter of 16.8 μm or less. The absorbent body 20 includes a first adhesive layer, a second adhesive layer adjacent to the first adhesive layer in the thickness direction, and an intervening absorbent layer including one or more absorbent layers sandwiched between the first adhesive layer and the second adhesive layer. The first adhesive layer and the second adhesive layer are the two adhesive layers adjacent to each other in the thickness direction, among the multiple adhesive layers provided in the absorbent body 20, that are the largest in thickness of the intervening absorbent layer in its natural state. An absorbent layer different from the intervening absorbent layer is provided on at least one of the outer side of the first adhesive layer in the thickness direction (the first adhesive layer side) and the outer side of the second adhesive layer in the thickness direction (the second adhesive layer side). When the diaper 1 is folded in half at the fold F at the center CL in the longitudinal direction, the bottom area is 150 cm ２After a 5 kg weight is placed on the diaper 1 for 24 hours, the average thickness of the interposed absorbent layer of the diaper 1 immediately after the weight is removed is 2.0 mm or less. Furthermore, when the thickness at the center of the width direction of the folded portion F (center C-C) immediately after the weight is removed is defined as the "immediate thickness," and the thickness at the center of the width direction of the folded portion F 72 hours after the weight is removed is defined as the "72-hour thickness," the value obtained by dividing the 72-hour thickness by the immediate thickness (72-hour thickness / immediate thickness) is 106.6% or less. The state of the weight and the measurement of each thickness will be described later.

[0078] Superabsorbent polymers are characterized by their high ability to absorb and retain liquid even in small amounts, and are less susceptible to pressure before absorbing moisture, and are less susceptible to changes in bulk (thickness) than absorbent materials such as liquid-absorbent fibers. By including a superabsorbent polymer in the absorbent core 20A, the diaper 1 can retain its absorption function as a disposable diaper, while also reducing the risk of the diaper 1 containing the superabsorbent polymer increasing in bulk when the diaper 1 is removed from its compressed state in a package. The absorbent core 20A of the absorber 20 of the diaper 1 of this embodiment includes a superabsorbent polymer (SAP) and liquid-absorbent fibers 201. The liquid-absorbent fibers 201 are cellulose fibers, which improves the diffusion of excrement and makes it easier to improve the feel of the absorbent core 20A against the skin.

[0079] The intervening absorbent layer 20b may be one or more absorbent layers, but does not include sheet members such as nonwoven fabric sheets or tissues. In other words, the term "absorbent layer" refers to a "layer" constituting the absorbent core 20A, in which liquid-absorbent fibers or superabsorbent polymers are molded to a predetermined thickness, and does not include sheets such as nonwoven fabric sheets or tissues. The intervening absorbent layer 20b may be one or more absorbent layers. In this embodiment, the intervening absorbent layer 20b includes the skin-side upper layer 24, the skin-side layer 21, and the middle layer 22, which are sandwiched between the adhesive layers m1 and m2 adjacent in the thickness direction. However, this is not limited to this. The non-skin-side layer 23 (one absorbent layer) sandwiched between the adhesive layers m3 and m4 adjacent in the thickness direction may also be the intervening absorbent layer 20b.

[0080] In this embodiment, the multiple sheet portions are composed of a core wrap sheet 25, a core wrap sheet 26, and an intermediate sheet 27. Each of the multiple sheet portions 25, 26, and 27 is formed of at least one of cellulose fibers and thermoplastic fibers having an average fiber diameter of 16.8 μm or less. Specifically, the core wrap sheet 25, the core wrap sheet 26, and the intermediate sheet 27 are each a hydrophilic nonwoven fabric formed of thermoplastic fibers having an average fiber diameter of 16.8 μm or less. A smaller average fiber diameter makes it easier to reduce the gaps between fibers compared to a larger average fiber diameter, thereby reducing the likelihood of the diaper 1 (absorbent body 20) becoming bulky after removal from the package. This reduces the risk of the absorbent body 20 becoming bulky compared to when thermoplastic fibers having an average fiber diameter greater than 16.8 μm are used for the absorbent body 20. Furthermore, because cellulose fibers are soft, when the multiple sheet portions are composed of cellulose fibers, the diaper 1 (absorbent body 20) becomes less likely to become bulky after removal from the package.

[0081] The thermoplastic fibers having an average fiber diameter of 16.8 μm or less are preferably polyethylene (PE), polypropylene (PP), or a combination of polyethylene (PE) and polypropylene (PP). Polyethylene (PE) and polypropylene (PP) fibers are soft and tend to make the absorbent body 20 softer than fibers such as polyethylene terephthalate (PET). This allows the diaper 1 to better conform to the wearer's body and movements, improves skin contact, and reduces discomfort during wear. This also helps to reduce the risk of the absorbent body 20 becoming bulky.

[0082] 4, in the absorbent body 20 of this embodiment, the multiple sheets and absorbent layers are fixed with adhesive layers (m1 to m4) made of an adhesive (HMA) such as a hot melt adhesive. Specifically, an adhesive layer m1 is provided between the core wrap sheet 25 and the skin side layer 21, an adhesive layer m2 is provided between the intermediate layer 22 and the intermediate sheet 27, an adhesive layer m3 is provided between the intermediate sheet and the non-skin side layer 23, and an adhesive layer m4 is provided between the non-skin side layer 23 and the core wrap sheet 26.

[0083] The skin-side layer 21 and the intermediate layer 22 are sandwiched between an adhesive layer m1 (first adhesive layer) between the core wrap sheet 25 and the skin-side upper layer 24 and the skin-side layer 21, and an adhesive layer m2 (second adhesive layer) between the intermediate layer 22 and the intermediate sheet 27. In this case, the skin-side upper layer 24, the skin-side layer 21, and the intermediate layer 22 form the intervening absorbent layer 20b. Of the multiple adhesive layers m1 to m4 provided in the absorbent body 20, the adhesive layers m1 and m2 are two adhesive layers adjacent in the thickness direction at which the thickness tb of the intervening absorbent layer 20b (the skin-side upper layer 24, the skin-side layer 21, and the non-skin-side layer 22) in its natural state is greatest. In addition, a non-skin-side layer 23 different from the intervening absorbent layer 20b is provided on the non-skin side of the adhesive layer m2 in the thickness direction.

[0084] When a weight W is placed on a folded diaper 1 for 24 hours and then the weight W is removed, the average thickness of the intermediate absorbent layer 20b of the diaper 1 immediately after the weight W is removed is 2.0 mm or less. Specifically, the intermediate absorbent layer 20b of this embodiment comprises a skin-side layer 21 and a non-skin-side layer 22. The average thickness of the intermediate absorbent layer 20b is the average sum of the thicknesses of the skin-side layer 21 and the non-skin-side layer 22, and the average thickness tb of the intermediate absorbent layer 20b of the diaper 1 of this embodiment is 2.0 mm. The smaller the average thickness of the intermediate absorbent layer 20b of the diaper 1 immediately after the weight W is removed, the thinner the absorbent core 20A can be, thereby reducing the risk of the diaper 1 becoming bulky. Therefore, the thickness of the absorbent core 20A (absorbent body 20) and the bulk of the diaper 1 can be more easily reduced than when the average thickness of the intermediate absorbent layer 20b is greater than 2.0 mm.

[0085] Furthermore, with respect to the thickness of the diaper 1 at the center C-C in the width direction of the folded portion F in a folded state immediately after the weight W of the diaper 1 is removed, the larger the value obtained by dividing the thickness after 72 hours by the thickness immediately after removal, the greater the thickness (bulk) of the diaper 1 after a predetermined time (72 hours) has elapsed since the diaper 1 was removed from the package. For the diaper 1 of this embodiment, the value obtained by dividing the thickness after 72 hours by the thickness immediately after removal is 106.6%. By setting the value obtained by dividing the thickness after 72 hours by the thickness immediately after removal to 106.6% or less, the risk of the diaper 1 becoming bulky can be reduced compared to when the value obtained by dividing the thickness after 72 hours by the thickness immediately after removal is greater than 106.6%.

[0086] These features allow the diaper 1 to have the liquid absorbency of an absorbent article, while the highly flexible fibers of the absorber 20 and the multiple adhesive and absorbent layers help to reduce the risk of the diaper 1 becoming bulky. This reduces discomfort when worn and makes it easier to store and carry the diaper 1 before wearing it.

[0087] Furthermore, for a diaper 1 from which the weight W has been removed, when the thickness of the diaper 1 in a folded state at the center C-C in the width direction of the folded portion F one week after the weight W has been removed is defined as the "thickness after one week," it is preferable that the value obtained by dividing the thickness after one week by the thickness immediately after (thickness after one week / thickness after immediate closure) is 112.2% or less. By providing a value obtained by dividing the thickness after one week by the thickness immediately after (thickness after one week / thickness after immediate closure) of 112.2% or less, the diaper 1 can be more flexible and maintain its absorbency even one week after removal from the package, thanks to the presence of multiple absorbent layers and adhesive layers. This improves the flexibility of the absorbent body 20, and reduces the risk of the diaper 1 becoming bulky while still maintaining its absorbency.

[0088] 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 F at the center in the longitudinal direction of the unfolded absorbent article, and the fold F in the folded state does not necessarily correspond to the lower end of the absorbent article when worn.

[0089] <<<State of the diaper 1 with the weight W placed on it>>> Generally, absorbent articles such as the diaper 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 in which it is stored, 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. For this reason, after the diaper 1 is taken out of the package, a weight W (with a base area of ​​150 cm) is placed on the diaper 1 in a folded state. ２By placing a weight of 5 kg on the diaper 1 for 24 hours, the pressure applied to the diaper 1 is equalized.

[0090] As shown in Fig. 7 , 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, aligning the widthwise center of the absorbent main body 10 (the center C-C of the diaper 1) with the widthwise center of the weight W, so that the weight W fits inside the absorbent main body 10 when viewed in the thickness direction. Fig. 7 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. 7 , the weight W may be placed on one diaper 1, or on a stack of multiple diapers 1. Because absorbent articles such as the diaper 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 absorbent articles must be such that the stacked state can be maintained and the stacked absorbent articles do not 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 stacked state was left to stand for 24 hours, and the thickness of all diapers 1 was measured using the method described below.

[0091] The sinker W has a base area of ​​150 cm ２ In this embodiment, a rectangular weight W is used, the length Lw1 of which is 15 cm in the longitudinal direction (vertical direction) and the length Lw2 of which is 10 cm in the width direction (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 may be made of any material, and may be made of metal such as stainless steel or iron.

[0092] <<<<Measuring the Thickness of the Folded Portion 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 thereon 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, and both can be measured by well-known methods. For example, the measurement can be performed using an Ozaki Seisakusho Dial Thickness Gauge, Large Type J-B with spring, or an equivalent. Specifically, using an Ozaki Seisakusho Dial Thickness Gauge, Large Type J-B with spring, the measurement point (the widthwise center of the folded portion F) is clamped between a pair of measuring terminals st, and a pressure of 9.0-12.0 gf / cm is measured using the pair of measuring terminals st. 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 8 is a diagram illustrating the measurement of the folded portion F. As shown in Figure 8, the pair of measuring terminals st are circular plates each having a diameter of 50 mm, and are arranged parallel to each other in the vertical direction (thickness direction of the diaper 1). The pair of measuring 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 portion where both measuring terminals st abut against the diaper 1 is measured as the "thickness." At this time, the measurement is performed with the center C-C 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 measuring terminals st.

[0093] For each absorbent layer, 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 an S-size diaper 1 and 0.58 mm to 0.69 mm for an XXL-size diaper 1. The first thickness t1 of the skin-side layer 21 is preferably 0.3 mm to 0.48 mm for an S-size diaper 1 and 0.45 mm to 0.65 mm for an XXL-size diaper 1. The average thickness of the absorbent body 20 is preferably 2.0 to 2.5 mm.

[0094] The average thickness t2 of the intermediate layer 22 is preferably 0.5 mm or greater. 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 better absorption of excreted liquid between 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. This allows for quick and temporary absorption of excreted liquid in the intermediate layer 22, and after diffusing the excreted liquid in the intermediate layer 22, it quickly transfers the excreted liquid to the non-skinside layer 23, ensuring absorbency. However, because an excessively thick intermediate layer 22 can cause stiffness, the average thickness (second thickness t2) of the intermediate layer 22 is preferably 2.5 mm or less.

[0095] The thicknesses (tb, t1 to t3) of the layers 20b, 21 to 23 can be measured using known methods. For example, with the diaper 1 in a natural, dry state without external forces, 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 absorbent body 20 components, the diaper 1 is cut at a predetermined location and then measured. Next, using an optical microscope (e.g., Keyence Corporation's VHX-7000 Digital Microscope or equivalent), the cut surface is placed upright and magnified (e.g., 30 to 100 times) and photographed. The focus of the magnified photograph is on the liquid-absorbent fibers 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 and 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 21-23 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 20b, 21-23. The average thickness values ​​obtained for each of the layers 20b, 21-23 are calculated and designated as the average thickness t1 (first thickness t1) of the skin-side layer 21, the average thickness t2 (second thickness t2) of the intermediate layer 22, the average thickness t3 (third thickness t3) of the non-skin-side layer 23, and the thickness tb of the intervening absorbent layer 20b. Note that when measuring the thickness, portions other than the low basis weight regions 211, 221, and 231 are measured. Furthermore, when the absorbent layer is bonded to the sheet portion (core wrap sheets 25, 26, intermediate sheet 27) via an adjacent adhesive layer m, as in the case of the interposed absorbent layer 20b, it is difficult to identify the portion 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."

[0096] 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 measured were as follows: for the S size, 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 the XXL size, 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.

[0097] Figure 9 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. In Figure 9, "Absorbent core configuration" indicates whether the absorbent core contains cellulose fibers or superabsorbent polymer (SAP). "Average fiber diameter of sheet portion" indicates the average fiber diameter of the fibers that make up the sheet portion of the absorbent body. "Thickness after 72 hours / thickness immediately after" indicates the value obtained by dividing the value of the thickness after 72 hours obtained by the method described above by the value of the thickness immediately after.

[0098] The results in Fig. 9 are specifically as follows: Diaper 1 had an absorbent core 20A comprising cellulose fibers and a superabsorbent polymer (SAP), the sheet portion (25, 26, 27) of the absorbent body 20 had an average fiber diameter of 16.8 µm, and the thickness of the intervening absorbent layer 20b (the skin-side upper layer 24, the skin-side layer 21, and the non-skin-side layer 22) was 2.0 mm, with the value obtained by dividing the 72-hour thickness by the immediate thickness being 106.6%. Diaper Product A had an absorbent core comprising cellulose fibers and a superabsorbent polymer (SAP), the sheet portion of the absorbent body had an average fiber diameter of 16.3 µm, the thickness of the intervening absorbent layer was 4.1 mm, and the value obtained by dividing the 72-hour thickness by the immediate thickness being 111.9%. The diaper product B has an absorbent core comprising cellulose fibers and a superabsorbent polymer (SAP), a sheet portion of the absorbent body having an average fiber diameter of 16.3 μm, an intervening absorbent layer having a thickness of 4.1 mm, and a value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards of 111.8%.The diaper product C has an absorbent core comprising cellulose fibers and a superabsorbent polymer (SAP), a sheet portion of the absorbent body having an average fiber diameter of 25 μm, an intervening absorbent layer having a thickness of 0.53 mm, and a value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards of 111.1%.

[0099] As can be seen from the results shown in Figure 9, the diaper 1 has the absorption function of an absorbent article due to the inclusion of SAP in the absorbent core 20A, while the average fiber diameter of the sheet portion is 16.8 µm, making it a flexible sheet. The thickness of the interposed absorbent layer 20b is 2.0 mm, and the value obtained by dividing the thickness after 72 hours by the thickness immediately after is 106.6%, which reduces the recovery of bulk of the diaper 1 and makes it easier to carry and store.

[0100] Product A has an absorbent core that contains SAP and has the absorption function of an absorbent article, and the average fiber diameter of the sheet portion is 16.3 μm, making it a flexible sheet, but the thickness of the interposed absorbent layer is 4.1 mm, and the value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards is 111.9%. Therefore, after a certain period of time, Product A regains its bulk and becomes bulky, making the diaper 1 inconvenient to carry and store.

[0101] Product B has an absorbent core equipped with SAP and has the absorption function of an absorbent article, and the average fiber diameter of the sheet portion is 15.8 μm, making it a flexible sheet, but the thickness of the interposed absorbent layer is 4.1 mm, and the value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards is 111.8%. Therefore, after a predetermined time has passed, Product B's bulkiness is restored and the diaper 1 becomes bulky, making it inconvenient to carry and store.

[0102] Product C has an absorbent core that contains SAP and thus has the absorption function of an absorbent article, and although the thickness of the intervening absorbent layer is 0.53 mm, the sheet portion has a relatively high rigidity due to an average fiber diameter of 25 μm, and the value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards is 111.1%. Therefore, after the predetermined time has passed, Product C's bulkiness is restored and the diaper 1 becomes bulky, making it inconvenient to carry and store.

[0103] Furthermore, a skin-side upper layer 24 is provided on the skin side of 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 in which the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by the SAP. The skin-side upper layer 24, which has a high volumetric ratio of the liquid-absorbent fibers 201, is located closer to the skin than the skin-side layer 21, thereby further reducing the wearer's perception of the unevenness of the SAP. Furthermore, because the skin-side upper layer 24 contains a large amount of the liquid-absorbent fibers 201, it further 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 arranged 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 that it can draw in excreted liquid without excessively retaining the excreted liquid, thereby reducing rewetting.

[0104] As shown in Fig. 5 and other figures, the absorbent core 20A preferably 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 the SAP: g / m) of the absorbent core 20A that is lower than the surrounding area. ２ 4 and other figures, the absorbent body 20 of this embodiment has low basis weight regions 211, 221 in the skin side layer 21 and the intermediate layer 22 along the longitudinal direction. Similarly, the non-skin side layer 23 also has a low basis weight region in which the basis weight of the absorbent core 20A (i.e., the total basis weight of the liquid-absorbent fiber 201 and the SAP: g / m ２ The absorbent core 20A has a low basis weight region 231 along the longitudinal direction where the thickness of the absorbent core 20A is low. In the low basis weight regions 211, 221, 231, the plurality of sheet portions 25, 26, 27 can easily approach and adhere to the absorbent core 20A, and each of the sheet portions 25, 26, 27 can easily enter the recessed portions of the low basis weight regions 211, 221, 231, which can reduce the risk that the sheet portions 25, 26, 27 covering each layer of the absorbent core 20A will increase the bulk of the absorbent core 20A.

[0105] The diaper 1 also contains cellulose fibers (so-called pulp fibers) and superabsorbent polymers (SAP). The low basis weight regions 211, 221, and 231 allow the absorbent body 20 to quickly absorb excrement from the low basis weight regions 211, 221, and 231 into the absorbent body 20 (inside each absorbent core 20A) when the wearer excretes in the diaper 1 and the absorbent body 20 receives the excrement. Cellulose fibers are soft and have a fast absorption rate, while superabsorbent polymers have high liquid retention properties, which facilitate the diffusion of excrement in the longitudinal and thickness directions of the absorbent core 20A.

[0106] In the absorbent core 20A having multiple absorbent layers, the low basis weight region 211 of the absorbent layer (skin-side layer 21) located on the skin side is preferably a slit penetrating in the thickness direction. In this case, excreted liquid falls into the low basis weight region 211, increasing the rate at which excreted liquid migrates 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 and SAP may be present, as long as at least a portion thereof has a portion penetrating in the thickness direction.

[0107] 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 only one low basis weight region 211-231, and they may be located on the center line C-C 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. Furthermore, the low basis weight regions 211, 221, and 231 only need to have a portion along at least the longitudinal direction, and may also have a portion along any direction other than the longitudinal direction. When the absorbent core 20A has multiple absorbent layers, at least one layer may have a low basis weight region.

[0108] As described above, the absorbent core 20A (absorbent layer) has a skin-side upper layer and a skin-side layer 21 (first absorbent layer) that are positioned closest to the skin in the thickness direction, and a non-skin-side layer 23 (second absorbent layer) that is positioned closer to the skin than the skin-side layer 21 (FIG. 5). When the diaper 1 is worn, on one side in the width direction of the crotch region M that is located between the wearer's crotch, it is preferable that the side end 23ae of the non-skin-side layer 23 is positioned outside (on one side of) the side end 21e of the skin-side layer 21, and that there is a portion k1 where the core wrap sheet 25 and the skin-side surface of the non-skin-side layer 23 are adhered, as shown in FIGS. As a result, the skin-side layer 21 and the intermediate layer 22 are sandwiched between the core wrap sheet 25 and the non-skin-side layer 23 widthwise inside the portion k1 where the absorbent core 20A (non-skin-side layer 23) is adhered to the core wrap sheet 25, which makes it easier to restrict the increase in bulk of the skin-side layer 21 and the intermediate layer 22 at portion k1, and therefore makes it easier to reduce the risk of the bulk of the absorbent core 20A (non-skin-side layer 23) increasing on the skin side.

[0109] As shown in Figure 4, in the diaper 1, on one side in the width direction of the crotch region M, the side end 23ae of the non-skin-side layer 23 is located outside the side end 21e of the skin-side layer 21, but in the portion other than the crotch region M in the longitudinal direction, on one side in the width direction, the side end 23ae of the non-skin-side layer 23 is located inside the side end 21e of the skin-side layer 21.

[0110] Furthermore, when the absorbent core 20A (absorbent layer) has a non-skin-side layer 23 (first absorbent layer) located closest to the skin in the thickness direction and an intermediate layer 22 (second absorbent layer) located closer to the skin than the non-skin-side layer 23 (Figure 5), it is preferable that, on the front side (one side) in the longitudinal direction of the crotch region M, the front end 22d of the intermediate layer 22 is located outside (on the front side) of the front end 23bd of the non-skin-side layer 23, and that there is a portion k2 where the core wrap sheet 26 and the skin-side surface of the non-skin-side layer 23 are bonded, as shown in Figures 4 and 10. Figure 10 is a cross-sectional schematic diagram of the absorbent body 20 of this embodiment. Figure 10 is a diagram illustrating a cross section at the center C-C in the width direction of the absorbent body 20. As a result, the non-skin side layer 23 is sandwiched between the core wrap sheet 26 and the intermediate layer 22 widthwise inside the portion k2 where the absorbent core 20A (intermediate layer 22) is adhered to the core wrap sheet 26, which makes it easier to restrict the increase in bulk of the non-skin side layer 23 at portion k2, thereby making it easier to reduce the risk of the bulk of the absorbent core 20A (non-skin side layer 23) increasing on the non-skin side.

[0111] It is preferable that the core wrap sheet 25 and the core wrap sheet 26 have a portion where the non-skin side of the core wrap sheet 25 and the skin side of the core wrap sheet 26 are bonded together inside the outer shape of the absorbent core 20A in the thickness direction. In this embodiment, as shown in Figures 4 and 5, when viewed in the thickness direction of the diaper 1, there are overlapping portions among 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, and the overlapping portions of these low basis weight regions 211, 221, 231 have an adhered portion between the core wrap sheet 25 located on the skin side of the absorbent core 20A and the core wrap sheet 26 located on the non-skin side of the absorbent core 20A. In the overlapping portions of the low basis weight regions 211, 221, and 231 in the thickness direction, the core wrap sheet 25 penetrates toward the non-skin side of the absorbent core 20, and the core wrap sheet 26 penetrates toward the skin side of the absorbent core 20, and the core wrap sheet 25 and the core wrap sheet 26 are adhesively fixed to each other, which tends to sandwich the absorbent core 20A. Note that the portion where the core wrap sheet 25 and the core wrap sheet 26 are adhered to each other includes not only a portion where the core wrap sheet 25 and the core wrap sheet 26 are adhesively fixed in direct contact with each other, but also a portion where the core wrap sheet 25 and the core wrap sheet 26 are adhesively fixed with another member interposed between them. Specifically, in this embodiment, the core wrap sheet 25 and the core wrap sheet 26 are adhesively fixed with the skin-side upper layer 24 and the intermediate sheet 27 interposed therebetween. This helps reduce the risk of the absorbent core 20A being sandwiched between the core wrap sheets 25 and 26 that are bonded together, thereby increasing the bulk of the absorbent core 20A. With regard to the "portion where the core wrap sheets 25 and 26 are bonded together," the other member between the core wrap sheets 25 and 26 may be a sheet member such as the intermediate sheet 27, or may be liquid-absorbent fibers 201 or SAP that have spilled out from the absorbent layers 21, 22, 23, and 24.In addition, the core wrap sheet 25 and the core wrap sheet 26 may be bonded together with a thin layer such as the skin-side upper layer 24 in between, or in a portion where the liquid-absorbent fiber 201 or SAP is provided at a thin thickness without being penetrated by the low basis weight regions 211, 221, 231.

[0112] The portion where the core wrap sheet 25 and the core wrap sheet 26 are bonded together is not necessarily the portion where all of the low basis weight regions 211, 221, and 231 overlap in the thickness direction. The core wrap sheet 25 and the core wrap sheet 26 may be bonded together in the low basis weight region of one absorbent layer in the thickness direction, or the absorbent core 20A may have an absorbent layer that is smaller than the outer shape of the absorbent core 20A, and the core wrap sheet 25 and the core wrap sheet 26 may be bonded together in the portion where the absorbent layer is not provided.

[0113] As shown in Figure 5 and other figures, the diaper 1 has a constricted portion 20c in the absorbent core 20A, which is constricted inward in the width direction in the crotch region M, which is located between the wearer's crotch when the diaper 1 is worn. 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 and where the width of the absorbent core 20A is partially shortened. The crotch region M of the diaper 1 is a portion that is sandwiched between the wearer's legs when worn. Therefore, the absorbent core 20A having the constricted portion 20c in the crotch region makes it easier for the diaper 1 to fit the shape of the wearer's body when worn, facilitating leg movement. In this embodiment, the skinside layer 21 and the intermediate layer 22 have constricted portions 212, 222, and the non-skinside layer 23 has a portion in the longitudinal center where the widthwise length L1 is longer than the widthwise lengths of the skinside layer 21 and the intermediate layer 22. As shown in the area with diagonal lines slanting downward to the left in Figure 5, this refers to the region in the longitudinal center of the absorbent core 20A, extending from one end of L1 in the width direction to one end of L2 in the width direction (from the other end of L1 in the width direction to the other end of L2), from the outside in the width direction to the constricted portion 20c when viewed in the thickness direction. In this adjacent region, it is preferable to have a portion where the non-skin side of the core wrap sheet 25 and the skin side of the core wrap sheet 26 are bonded together. As described above, the bonded portion of the core wrap sheet 25 and the core wrap sheet 26 includes not only a portion where the core wrap sheet 25 and the core wrap sheet 26 are bonded together in a direct contact state, but also a portion where the core wrap sheet 25 and the core wrap sheet 26 are bonded together with another member interposed therebetween. This makes it easier to maintain the absorbent core 20A sandwiched between the core wrap sheets 25 and 26 that are bonded together, and makes it easier to reduce the risk of the absorbent core 20A becoming bulky.

[0114] As shown in Figure 3 and other figures, the diaper 1 preferably has a top sheet (surface sheet) 12 located closer to the skin than the core wrap sheet 25, and a back sheet (back surface sheet) 13 located closer to the skin than the core wrap sheet 26, and the top sheet 12 and the back sheet 13 are preferably bonded together in a region. The back sheet 13 of the diaper 1 is formed of a back sheet 13a, which is a liquid-impermeable sheet, and a back sheet 13b, which is an outer sheet. In the diaper 1 of this embodiment, the non-skin-side surface of the top sheet 12 and the skin-side surface of the back sheet 13 are bonded together in a region at either the widthwise end or the longitudinal end of the absorbent main body 10. This facilitates maintaining the absorber 20 sandwiched between the top sheet 12 and the back sheet 13, thereby reducing the risk of the absorber 20 becoming bulky. The portion where the top sheet 12 and the back sheet 13 are bonded may be a portion where the top sheet 12 and the back sheet 13 are bonded in a state where they are in direct contact with each other, or may be a portion where the top sheet 12 and the back sheet 13 are indirectly bonded via a member between them.

[0115] The absorbent core 20A may include multiple absorbent layers in which the volume occupied by superabsorbent polymer (SAP) is greater than the volume occupied by cellulose fibers. Because superabsorbent polymers are small before absorbing moisture and are less likely to increase in bulk, the risk of the absorbent core 20A increasing in bulk can be reduced. Furthermore, it is preferable that the multiple absorbent layers include cellulose fibers and have pulp layers in which the volume occupied by the cellulose fibers is greater than the volume occupied by the superabsorbent polymer. Unlike superabsorbent polymers, cellulose fibers are less likely to swell excessively even in the presence of moisture. Therefore, including a pulp layer can help reduce the risk of the absorbent core 20A increasing in bulk excessively even in the presence of moisture.

[0116] The absorbent core 20A of the diaper 1 of this embodiment has multiple absorbent layers: 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 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 the liquid-absorbent fibers 201 is larger than the volume occupied by SAP. The non-skin-side layer 23 is a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fibers 201. Each layer also has low basis weight regions 211, 221, 231, each having a basis weight lower than the surrounding area.

[0117] When excrement is received while the absorbent core is being worn, the skin-side layer 21, which has a high volume occupancy of SAP, first absorbs the excrement, while the low basis weight regions 211 promote diffusion of the excrement toward the non-skin side in the longitudinal and thickness directions. Meanwhile, the intermediate layer 22, which has a high volume occupancy of liquid-absorbent fibers 201, quickly and temporarily absorbs excrement that migrates from the low basis weight regions 211 to 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 easily migrates from the low basis weight regions 221 to the non-skin side layer 23, and from the low basis weight regions 231 of the non-skin side layer 23 toward the deeper side of the non-skin side layer 23. This facilitates drawing excrement deep into the absorbent core, improving absorbency. Furthermore, since the volume occupancy of SAP in the non-skinside layer 23 is high, excreted liquid is firmly absorbed and retained by the SAP in the non-skinside layer 23. This allows the absorbent core 20A to have a desired absorption function and flexibility while being thin, thereby reducing the risk of the diaper 1 becoming bulky, which not only reduces the risk of inconvenience in carrying and storing the diaper but also makes it easier to fit the wearer's body and movements.

[0118] The comparison of the volumes occupied by the liquid-absorbent fiber 201 and the SAP in each of the skin-side layer 21, the middle 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 its natural, dry state, in which no external force is acting, 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 Corporation Digital Microscope VHX-7000 or equivalent). The liquid-absorbent fiber 201 and the SAP are identified in the photographed cross-sectional image. Then, in the cross-sectional image, it is confirmed that the following layers are stacked in this 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 the area occupied by the SAP, a skin-side layer 21 in which the area occupied by the SAP is larger than the area occupied by the liquid-absorbent fibers 201, a middle layer 22 in which the area occupied by the liquid-absorbent fibers 201 is larger than the area occupied by the SAP, and a non-skin-side layer 23 in which the area occupied by the SAP is larger than the area occupied by the liquid-absorbent fibers 201. If the above is confirmed, the four layers 21 to 24 of this embodiment are defined. 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 SAP in any of the cross-sectional images is larger than the area occupied by the liquid-absorbent fiber 201, then that layer is a layer in which "the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fiber," and if the area occupied by the liquid-absorbent fiber 201 in any of the cross-sectional images is larger than the area occupied by SAP, then that layer is a layer in which "the volume occupied by the liquid-absorbent fiber is larger than the volume occupied by SAP."

[0119] In addition, a comparison of the volumes occupied by the liquid-absorbent fibers 201 and the SAP in each layer can also be made by visualizing the liquid-absorbent fibers 201 and the SAP using X-ray microtomography (X-ray CT), for example, by the method described below: ScienceDirect, Carbohydrate Polymers 254, Mathias A. Hobisch et al., February 15, 2021, "How cellulose nanofibrils and cellulose microparticles impact paper strength—A visualization approach", Section "3.6. X-ray microtomography", https: / / www.sciencedirect.com / science / article / pii / S0144861720315794.

[0120] 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 ２ The average basis weight of the skin side layer 21 is preferably about 82 g / m ２ When the diaper 1 is an XXL size, the average basis weight of the non-skinside 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 having 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 the SAP. As a result, the feel of the skin side (gritty feeling of the SAP) is less likely to deteriorate.

[0121] Furthermore, as described above, when there is a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fibers 201 and a layer (pulp layer) in which the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by SAP, it is preferable that the SAP layer and the pulp layer are adjacent in the thickness direction and an adhesive is provided between the SAP layer and the pulp layer. Specifically, as shown in Fig. 4, an adhesive (adhesive layer m2) is provided on the skin side of the intermediate sheet 27 and an adhesive (adhesive layer m3) is provided on the non-skin side of the intermediate sheet 27 between the non-skin side layer 23 which is an SAP layer and the intermediate layer 22 which is a pulp layer. Note that the adhesive provided between the SAP layer and the pulp layer may be an adhesive layer that directly bonds the SAP layer and the pulp layer, or may be an adhesive (adhesive layer) provided to bond them via the intermediate sheet 27, as in this embodiment.

[0122] The superabsorbent polymer of the non-skin-side layer 23 (SAP layer) is a material that is resistant to bulk recovery and has high liquid retention, thereby improving the absorbent function of the absorbent core 20A while reducing the risk of the absorbent core 20A becoming bulky. However, superabsorbent polymers are harder than cellulose fibers and tend to feel uneven against the skin. On the other hand, cellulose fibers (pulp fibers) have better liquid diffusivity than SAP and are softer against the skin than superabsorbent polymers, but because they are fibrous, they tend to recover bulk more easily than superabsorbent polymers. Therefore, by arranging the non-skin-side layer 23 and the intermediate layer 22 adjacent to each other in the thickness direction, the thickness of the non-skin-side layer 23, which contains a large amount of superabsorbent polymer that is relatively hard and has unevenness, can be easily cushioned by the relatively soft intermediate layer 22. Furthermore, by fixing the non-skinside layer 23 and the intermediate layer 22 with an adhesive, it is possible to easily suppress the movement of the cellulose fibers (particularly the intermediate layer 22), thereby reducing the risk of voids being generated between the cellulose fibers in the intermediate layer 22. This allows the diaper 1 to have the absorption function of an absorbent article while reducing the risk of the absorbent core 20A becoming bulky.

[0123] Similarly, in a case where the diaper 1 has a layer (SAP layer) in which the volume occupied by SAP is larger than the volume occupied by the liquid-absorbent fibers 201 and a layer (pulp layer) in which the volume occupied by the liquid-absorbent fibers 201 is larger than the volume occupied by SAP, it is preferable that the average thickness of the pulp layer is 1.5 times or less than the average thickness of the SAP layer. This allows the amount of cellulose fiber in the absorbent layer (absorbent core 20A) to be reduced compared to when the thickness of the pulp layer is greater than 1.5 times the thickness of the SAP layer, and makes it easier to reduce the risk of the absorbent core 20A becoming bulky. In the diaper 1 of this embodiment, the first thickness t2 of the intermediate layer 22, which is a pulp layer, is 1.5 times or less the first thickness t1 of the skin-side layer 21, which is a SAP layer (t2≦t1×1.5). Furthermore, the first thickness t2 of the intermediate layer 22, which is a pulp layer, is 1.5 times or less the third thickness t3 of the non-skin-side layer 23, which is a SAP layer (t2≦t3×1.5).

[0124] Furthermore, it is preferable that the absorbent body 20 have compressed portions compressed in the thickness direction. Fig. 10 is a schematic plan view of the absorbent body 20 as seen from the skin side. As shown in Fig. 10, in this embodiment, the skin side layer 21 has a plurality of compressed points 50 formed by compressing the skin side layer 21 (absorbent core 21) in a dotted pattern in the thickness direction. The "compressed points 50" are portions of the absorbent core 21 that have been compressed in the thickness direction by embossing. Due to the compression, the fiber density of the absorbent core 21 is higher than that of uncompressed portions. In this embodiment, the compressed points 50 are formed by a collection of dots (circles), but the compressed points 50 may also be formed in a line shape (straight line, curved line), for example. Alternatively, the compressed points or lines may be formed discretely within a predetermined region. Furthermore, the pattern of the dotted compressed portions 50 is such that the dotted compressed portions 50 are arranged in a dotted grid pattern (a so-called quilting pattern) as a whole, as shown in Figure 7, but other patterns are also possible. Because such dotted compressed portions 50 are high-density, thin portions, providing the absorbent body 20 with dotted compressed portions 50 reduces the risk of the absorbent body 20 becoming bulky. Furthermore, localized compression prevents collapse of the absorbent body 20 without impairing the flexibility of the absorbent core 20A (absorbent layers 21-24). Note that the dotted compressed portions 50 are not limited to being provided in the skin-side layer 21, but may also be provided in the intermediate layer 22 or non-skin-side layer 23.

[0125] As described above, the absorbent body 20 preferably includes a plurality of sheet portions, each of which has an intermediate sheet 27 between adjacent absorbent layers in the thickness direction. The intermediate sheet 27 is preferably made of at least one of cellulose fibers and thermoplastic fibers having an average fiber diameter of 16.8 μm or less, and preferably includes an adhesive layer (intermediate adhesive layer) on one surface of the intermediate sheet 27 in the thickness direction. In the diaper 1 of this embodiment, as shown in FIG. 4 , the intermediate sheet 27 is located between the intermediate layer 22 and the non-skinside layer 23, which are adjacent in the thickness direction. Examples of the intermediate sheet 27 include sheet-like members such as tissue made of cellulose fibers (pulp fibers) and nonwoven fabric made of thermoplastic fibers having an average fiber diameter of 16.8 μm or less. Furthermore, by providing the adhesive layer m2 on the skin-side surface of the intermediate sheet 27, the adhesive layer m2 on the skin-side surface of the intermediate sheet 27 provided between the intermediate layer 22 and the non-skin-side layer 23 is bonded and fixed to the intermediate layer 22, which makes it easier to restrict the movement of the liquid-absorbent fibers and superabsorbent polymer (SAP) in the intermediate layer 22 by the adhesive, and reduces the risk of an increase in bulk of the intermediate layer 22. Similarly, by providing the adhesive layer m3 on the non-skin-side surface of the intermediate sheet 27, the adhesive layer m3 on the non-skin-side surface of the intermediate sheet 27 provided between the intermediate layer 22 and the non-skin-side layer 23 is bonded and fixed to the non-skin-side layer 23 by the adhesive, which makes it easier to restrict the movement of the superabsorbent polymer (SAP) in the non-skin-side layer 23 by the adhesive, and reduces the risk of an increase in bulk of the non-skin-side layer 23. This makes it easier to reduce the risk of an increase in bulk of the absorbent core 20A.

[0126] In the case where, as in the present embodiment, an intermediate sheet 27 is provided between the plurality of absorbent layers (the intermediate layer 22 and the non-skin side layer 23) adjacent in the thickness direction in addition to the core wrap sheets 25 and 26 in the plurality of sheet portions, the intermediate sheet 27 is preferably formed of at least one of cellulose fiber and thermoplastic fiber having an average fiber diameter of 16.8 μm or less, and the core wrap sheet 25, the core wrap sheet 26, and the intermediate sheet 27 each have a basis weight of 15 g / m ２ More preferably, the thermoplastic fibers have a basis weight of 15 g / m ２The following thermoplastic fibers are soft fibers: ２ Nonwoven fabrics formed from the following thermoplastic fibers are soft and flexible sheets. Therefore, by using such fibers for the core wrap sheet 25, the core wrap sheet 26, and the intermediate sheet 27, the risk of the absorbent body 20 becoming bulky can be reduced.

[0127] With respect to the intermediate sheet 27, it is more preferable that the core wrap sheet 25 or the core wrap sheet 26 has a portion bonded to the intermediate sheet 27. In this embodiment, as shown in Figure 4, there is a portion bonded between the core wrap sheet 25 and the intermediate sheet 27 by adhesive layers m1 and m2. This allows the skin side layer 21 and the intermediate layer 22 to be sandwiched between the core wrap sheet 25 and the intermediate sheet 27, and the adhesive layers m1 and m2 tend to restrict the movement of the superabsorbent polymer (SAP) and liquid-absorbent fiber 201 in the skin side layer 21 and the intermediate layer 22, thereby reducing the risk of the skin side layer 21 and the intermediate layer 22 becoming bulky. In addition, there is a portion bonded between the core wrap sheet 26 and the intermediate sheet 27 by adhesive layers m3 and m4. As a result, the non-skin side layer 23 is sandwiched between the core wrap sheet 26 and the intermediate sheet 27, and the adhesive of the adhesive layers m3 and m4 tends to restrict the movement of the superabsorbent polymer (SAP) in the non-skin side layer 23, thereby making it easier to reduce the risk of the non-skin side layer 23 becoming bulky.

[0128] Figure 12 is a plan view illustrating the regions of the core wrap sheet 26 where SAP particles and adhesive are provided. Figure 13 is a photograph of a portion of the skin-side surface of the core wrap sheet 26 in the inner region IR, magnified 40 times. Figure 14 is a photograph of a portion of the skin-side surface of the core wrap sheet 26 in the outer region OR, magnified 40 times. Figure 12 shows the core wrap sheet 26 in an expanded and stretched state as viewed from the skin side (other side) in the thickness direction. In the core wrap sheet 26 (skin-side surface) in Figure 12, SAP particles are provided in the hatched divided regions 23a-23c to form the non-skin-side layer 23 (absorbent core 20A). The region of the core wrap sheet 26 located inside the outermost ends 23es, 23es of the non-skin-side layer 23 in the width direction is referred to as the inner region IR. Furthermore, the region of the core wrap sheet 26 located outside the outermost ends 23es, 23es of the non-skin side layer 23 in the width direction is referred to as the outer region OR.

[0129] 13, the width of the fibrous (i.e., thin strip) adhesive is smaller than the particle size of the SAP particles, and the adhesive penetrates between the SAP particles. Therefore, as described above, the SAP particles are easily fixed to each other via the adhesive, the SAP particles are less likely to shift position, and the absorbent core is prevented from losing its shape.

[0130] It can also be seen that the amount of strip-shaped adhesive applied per unit area (i.e., coating density) is lower in Figure 14 compared to Figure 13. That is, the number of intersections between strip-shaped (fibrous) adhesives per unit area in the inner region IR (see Figure 13) is greater than the number of intersections between strip-shaped (fibrous) adhesives per unit area in the outer region OR (see Figure 14). The more adhesive that comes into contact with the absorbent layer (non-skinside layer 23), the greater the portion of the non-skinside layer 23 that is adhered and fixed to the core wrap sheet 26. This reduces the risk of the core wrap sheet 26 increasing the bulk of the non-skinside layer 23, and therefore helps to reduce the risk of the absorbent core 20A increasing in bulk.

[0131] The number of intersections between band-like (fibrous) adhesives per unit area can be counted by taking a photograph like the one shown in Figures 13 and 14 and performing image analysis, for example. Furthermore, when measuring the amount of adhesive applied (coating density) in the outer region OR and the inner region IR, for example, the adhesive is colored using bamboo charcoal or the like, then photographed, and the photographed image is digitized and subjected to binarization processing to extract the adhesive. The area of ​​the portion of the region to be measured where the adhesive is applied can then be calculated to determine the adhesive coating density.

[0132] The average particle size of SAP can be measured using an electromagnetic sieve shaker (e.g., AS-200 model manufactured by Retsch) as follows. The electromagnetic sieve shaker has sieves No. 1 to No. 7 with different mesh sizes (e.g., mesh sizes: 850, 600, 500, 355, 300, 250, and 150 μm) and a tray. First, the weights of the sieves No. 1 to No. 7 and the tray are measured and designated as measurement value A. Next, from bottom to top, the tray and sieves with mesh sizes of 150, 250, 300, 355, 500, 600, and 850 μm are stacked and set in the shaker. Next, 50 g of SAP is placed on the top sieve with an 850 μm mesh size, and the sieve is covered and secured with a pressure pad. Next, the shaker is set to 1.35 mm amplitude (in the case of the AS-200 model, the amplitude adjustment dial is 45), continuous operation for 30 minutes, and shaking is started to perform a 30-minute shaking test. After the shaking test is completed, the weight of the SAP remaining on each of the first to seventh sieves, the sieves, and the tray is measured and recorded as measurement value B. From these data, the distribution of SAP by particle size = (B - A) / (total weight of SAP remaining on each sieve and on the tray) x 100 (%) is calculated.

[0133] Furthermore, it is preferable that the longitudinal length (length from the top to the bottom in the vertical direction) L10 (see FIG. 1) of the diaper 1 in the folded state (the pants-type state in the natural state shown in FIG. 1) is at least 85.3% of half the length L11 (see FIG. 2) from the top to the bottom in the vertical direction of the diaper 1 in the unfolded and stretched state (at maximum stretch) (L10≧L11×½×85.3%).

[0134] According to the above, the vertical length of the diaper 1 in the folded state (in a pants-type state in its natural state) is ensured, and the change in the vertical (longitudinal) length of the diaper 1 is reduced, compared to when the length L10 is less than 85.3% of half the length L11. This makes it difficult for the absorbent body 20 to shrink in the longitudinal direction, thereby reducing the risk of deformation of the absorbent body 20, thereby reducing the risk of gaps forming within the absorbent core 20A. If gaps were to form within the absorbent core 20A, the superabsorbent polymer (SAP) and liquid-absorbent fibers 201 within the absorbent core 20A would shift, increasing the bulk of the absorbent core 20A. By reducing the risk of gaps forming within the absorbent core 20A, the risk of the absorbent core 20A increasing in bulk is more easily reduced.

[0135] In the diaper 1, as shown in FIG. 1, it is preferable that there be no elastic members that continuously extend across the absorbent core 20A (absorbent layers 21-24) from one end to the other in the width direction. FIG. 1 shows only the portions of the elastic members of the diaper 1 that are subject to stretching (so-called effective length portions). As shown in FIG. 1, among the front and rear waist elastic members 33, 43, those that overlap the absorbent core 20A in the longitudinal direction are cut at a portion that overlaps the absorbent core 20A in the thickness direction, and thus are not subject to stretching. Thus, in the diaper 1 of this embodiment, the effective length portions of the waist elastic members 33, 43 do not continuously extend across the absorbent core 20A from one end to the other in the width direction. This makes it difficult for the absorbent core 20A (absorbent body 20) to shrink in the width direction, reducing the risk of deformation of the absorbent core 20A and reducing the risk of gaps forming within the absorbent core 20A. If gaps form within the absorbent core 20A, the superabsorbent polymer (SAP) and liquid-absorbent fibers 201 within the absorbent core 20A will move, increasing the bulk of the absorbent core 20A. By reducing the risk of gaps forming within the absorbent core 20A, it becomes easier to reduce the risk of the absorbent core 20A increasing in bulk.

[0136] Regarding the absorbent core 20A, the absorbent core 20A comprises cellulose fibers, and the density of the absorbent core 20A is 0.2 g / cm３ 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 smaller the gaps between the cellulose fibers (liquid-absorbent fibers 201) and the superabsorbent polymer (SAP) inside the absorbent core 20A. Also, cellulose fibers are soft fibers. Therefore, when the density of the absorbent core 20A is 0.2 g / cm or more, the gaps between the cellulose fibers (liquid-absorbent fibers 201) and the superabsorbent polymer (SAP) inside the absorbent core 20A become smaller. ３ By setting the density of the absorbent core 20A to 0.2 g / cm or more, it is possible to achieve a density of 0.2 g / cm without including cellulose fibers. ３ When a force is applied in the thickness direction of the absorbent core 20A (diaper 1), the absorbent core 20A (diaper 1) is less likely to be compressed than when the size is smaller, and the bulk of the absorbent core 20A (diaper 1) is less likely to recover even when the force in the thickness direction is released.

[0137] In addition, as mentioned above, when folded in half, the base area is 150 cm ２ It is preferable that, after placing a 5 kg weight W on the diaper 1 for 24 hours, the thickness of the center (center C-C) of the width direction of the folded portion F of the diaper 1 after removing the weight W is 6.5 mm or less. Because the absorbent main body 10 is a particularly thick portion of the diaper 1, by making the thickness of the center C-C of the width direction of the folded portion F of the diaper 1 after removing the weight W 6.5 mm or less, the thickness of the diaper 1 can be made thinner than when the thickness of the center C-C of the width direction of the folded portion F is greater than 6.5 mm, making the diaper 1 easier to store and carry.

[0138] Furthermore, when folded in half as described above, the base area is 150 cm ２ In a torsion test in which a weight W of 5 kg is placed on the diaper 1 for 24 hours, and then the weight W is removed, the diaper 1 is folded in half and twisted around an imaginary axis along the width direction by gripping the longitudinal centers of both widthwise end portions and the diaper 1 is also folded in half and twisted around an imaginary axis along the width direction by gripping the longitudinal centers of both widthwise end portions and the diaper 1 is also twisted around an imaginary axis along the length direction, the diaper 1 preferably has a torque value of 23.4 mN·m or less. The lower the torque value in the torsion test, the lower the torsional rigidity of the diaper 1, and therefore the easier it is to fold the diaper 1, the more flexible it can be, and the easier it is to store and carry the diaper 1.

[0139] <<<Regarding the Torsion Test>>> Figures 15A and 15B are explanatory diagrams of the "torsion test." Figure 15A illustrates a measurement method in which the diaper 1 is twisted around an imaginary axis Va1 along the width direction of the diaper 1. Figure 15B illustrates a measurement method in which the diaper 1 is twisted around an imaginary axis Va2 along the up-down direction of the diaper 1. Note that 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%.

[0140] (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 15A and 15B, 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 C1 extending along the vertical direction is drawn on the diaper 1, and a line C2 extending along the width direction is drawn on the diaper 1. The intersection of the two lines C1 and C2 is designated as the reference point o.

[0141] (2) In the torque tester, 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 tester is defined as 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 set to 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.

[0142] (3) When twisting the diaper 1 around the imaginary axis Va1 along the width direction as shown in Figure 15A, the gripping positions of the zippers 60 are set at positions p1, 30 mm to the right of the reference point o in the width direction, and p2, 30 mm to the left of the reference point o in the width direction. 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 located 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).

[0143] (4) With the diaper 1 set as described above, the upper zipper 60 is rotated clockwise (positive rotation) to twist the diaper 1 (the diaper 1 is twisted so that the waist portion of the diaper 1 in the right drawing of FIG. 15A is positioned toward the front of the page). The diaper 1 is then returned to its initial state, and the upper zipper 60 is rotated 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°. The average torque value (mN·m) at a measurement angle of 60° during clockwise rotation and a measurement angle of 60° during counterclockwise rotation is calculated.

[0144] (5) When twisting the diaper 1 around the imaginary axis Va2 in the up-down direction as shown in Figure 15B, the gripping positions of the zippers 60 are set to positions p3 and p4, which are 50 mm above and below the reference point o in the up-down direction, respectively. In other words, the zipper spacing is set to 100 mm. Specifically, the lower end of the upper zipper 60 is aligned with position p3 of the diaper 1, and the upper end of the lower zipper 60 is aligned with position p4 of the diaper 1. The center of the zipper 60 in the horizontal direction is also aligned with the reference point o of the diaper 1. This allows the diaper 1 to be twisted around the imaginary axis Va2 in the up-down direction by gripping the widthwise center of both vertical end portions of the diaper 1.

[0145] (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 drawing of Figure 15B is positioned toward the front of the page). Then, return the diaper 1 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°. The average torque value (mN·m) at a measurement angle of 60° during clockwise rotation and a measurement angle of 60° during counterclockwise rotation is calculated.

[0146] (7) The torque value when twisting around the virtual axis Va1 ( FIG. 15A ) and the torque value when twisting around the virtual axis Va2 ( FIG. 15B ) are measured multiple times (e.g., n = 3 times) for each measurement. Regardless of the measurement direction, multiple measurements are not performed on the same diaper 1; a different diaper 1 is prepared for each torque measurement. 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 then calculated (rounded to one decimal place). This average value is the torque value of the diaper 1 (pants-type absorbent article) before absorption.

[0147] Of the intervening absorbent layers 20b, it is preferable that one or more absorbent layers (skin-side layer 21, intermediate layer 22) located away from the absorbent layer (skin-side upper layer 24) located closest to the skin in the thickness direction do not contain nonwoven fabric. The skin-side layer 21 and intermediate layer 22 in this embodiment are layers provided with SAP and cellulose fibers (pulp fibers), and do not contain sheet members such as nonwoven fabric. This helps to reduce the risk of the absorbent body 20 (absorbent core 20) becoming bulky, making the absorbent article easier to store and carry.

[0148] 4, it is preferable that the absorbent layer (skin-side upper layer 24) of the interposed absorbent layer 20b located closest to the skin 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 excessive swelling of the skin-side upper layer 24 in a humid environment, which could increase the bulk of the absorber 20. This reduces the risk of the diaper 1 becoming bulky, making it easier to store and carry.

[0149] 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 without including the skin-side upper layer 24. That is, the skin-side layer 21 may be the absorbent layer of the intervening absorbent layers 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 resin, water-absorbent resin powder) provided in the skin-side layer 21 has a liquid permeation rate under load of more than 10 seconds. This allows the diaper 1 to maintain the absorption function of an absorbent article while reducing the risk of the absorbent article becoming bulky, as compared to when the liquid permeation rate under load of the skin-side layer 21 is 10 seconds or less, thereby facilitating storage and transport of the absorbent article.

[0150] The liquid permeation rate under load of the superabsorbent polymer (water-absorbent resin, water-absorbent resin powder) of the skin-side layer 21 can be measured by a known method. For example, it is measured by the method described in JP 2019-41876 A. That is, 0.32±0.005 g of water-absorbent resin powder is immersed in 100 mL of physiological saline (0.9% by mass sodium chloride solution) in a 100 mL glass beaker and left for 60 minutes. Separately, a cylindrical filtration tube is prepared at the bottom of the opening of a vertically standing cylinder (inner diameter 25.4 mm) equipped with a wire mesh (150 μm mesh, Sansho Hanbai Biocolumn Sintered Stainless Steel Filter 30SUS) and a capillary tube (inner diameter 4 mm, length 8 cm) with a stopcock (inner diameter 2 mm). With the stopcock closed, the entire contents of the beaker, including the swollen measurement sample, are poured into the cylindrical tube. Next, a 2 mm diameter cylindrical rod equipped with a 25 mm diameter wire mesh at the tip with 150 μm mesh openings is inserted into the cylindrical filtration tube so that the wire mesh and the test sample come into contact, and a weight is placed on the test sample so that a load of 2.0 kPa is applied. After leaving it in this state for 1 minute, the stopcock is opened to allow the liquid to flow, and the time T1 (seconds) until the liquid level in the cylindrical filtration tube reaches the 40 mL scale line from the 60 mL scale line (i.e., 20 mL of liquid passes through) is measured. Using the measured time T1 (seconds), the liquid passage rate under load at 2.0 kPa is calculated using the formula: Liquid passage rate under load (seconds) = T1 - T0. In this formula, T0 (seconds) is the time required for 20 mL of saline to pass through the wire mesh without the test sample in the cylindrical filtration tube. The measurement is carried out at a temperature of 23±2° C. and a relative humidity of 50±5%, and the water-absorbent resin is kept in the same environment for 24 hours or more before the measurement.

[0151] 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. 16 is a schematic cross-sectional view of the absorbent body 20 showing a modified example of the skin-side layer 21. As shown in FIG. 16, the modified skin-side layer 21 has high-basis weight regions 213 in which the basis weight of SAP is higher than that of the surrounding areas. In the high-basis weight regions 213, points S of maximum thickness 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, low-basis weight regions 214 in which the basis weight of SAP is lower than that of the high-basis weight regions 213 are formed between adjacent points S of maximum thickness (i.e., around the high-basis weight regions 213). However, as long as the points S of maximum thickness are located intermittently in the longitudinal direction and the width direction, a portion of the space between adjacent points S of maximum thickness may be formed by the high basis weight region 213. In other words, a portion of the space between adjacent points S of maximum thickness may be connected by the high basis weight region 213.

[0152] 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 present" not only means that no SAP particles are present, but also means that there are only a small number of laminated SAP particles, and that no SAP particles are present at all.

[0153] In the modified absorbent body 20, the low basis weight regions 214 (low basis weight laminated regions 214E and non-laminated regions 214N) serve as folding 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 points include the low basis weight laminated regions 214E that can absorb and retain excrement, and the 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 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.

[0154] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0155] In the above-described embodiment, the absorbent core 20A contains SAP (super absorbent polymer) and cellulose fibers and includes the skin-side upper layer 24, the skin-side layer 21, the intermediate layer 22, and the non-skin-side layer 23. However, this is not limiting. The absorbent core 20A may be configured to include at least SAP and include multiple absorbent layers in the thickness direction. For example, in a diaper having two absorbent layers, the absorbent core 20A may not contain cellulose fibers, but may include a sheet consisting solely of SAP (a so-called SAP sheet) as the skin-side layer, an absorbent core having a sheet consisting solely of SAP as the non-skin-side layer, and an intermediate sheet disposed between the skin-side layer and the non-skin-side layer. In this case, the intermediate sheet may be tissue or nonwoven fabric. If an adhesive (adhesive layer) is provided on the skin-side surface of the intermediate sheet, the adhesive layer between the skin-side layer and the skin-side core wrap sheet and the skin-side layer sandwiched between the adhesive layers between the skin-side layer and the intermediate sheet may serve as intervening absorbent layers. In such a case, the risk of the diaper 1 becoming bulky can be reduced by making the average thickness of the intervening absorbent layer 2.0 mm or less and making the value obtained by dividing the thickness after 72 hours by the thickness immediately afterwards 106.6% or less.

[0156] The number of absorbent layers stacked in the thickness direction of the absorbent core can be set as desired as long as it is at least two. The positions and numbers of adhesives (adhesive layers) and intermediate sheets in the thickness direction can also be changed depending on the number, composition, size, etc. of the absorbent layers.

[0157] 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, the problem of excreted fluid leakage is unlikely to occur.

[0158] 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 limiting. 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.

[0159] In a configuration in which an intermediate sheet 27 is not provided between the intermediate layer 22 and the non-skin side layer 23, and an adhesive (adhesive layer) is provided between the intermediate layer 22 and the non-skin side layer 23, the non-skin side layer 23 sandwiched between the adhesive layer between the intermediate layer 22 and the non-skin side layer 23 and the adhesive layer between the non-skin side layer 23 and the core wrap sheet 26 can be used as the interposed absorbent layer 20b.

[0160] Regardless of whether an intermediate sheet 27 is provided between the intermediate layer 22 and the non-skin side layer 23 or not, in a configuration in which no adhesive is provided between the skin side upper layer 24 and the skin side layer 21, between the skin side layer 21 and the intermediate layer 22, or between the intermediate layer 22 and the non-skin side layer 23, the skin side upper layer 24, the skin side layer 21, the intermediate layer 22, and the non-skin side layer 23 sandwiched between the adhesive layer between the skin side layer 21 and the core wrap sheet 25 and the adhesive layer between the non-skin side layer 23 and the core wrap sheet 26 can be used as an interposed absorbent layer 20b.

[0161] 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, a sheet such as an adhesive or 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 greater 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 in the skin-side layer 21 to suppress rewet.

[0162] Furthermore, even when the intermediate layer 22 and the non-skin side layer 23 are integrated, it is desirable that the SAP contained in the skin side layer 21 have a liquid absorption rate, as measured by the vortex method, that is slower than the SAP contained in the non-skin side layer 23. This makes it easier for the excrement to diffuse in the planar direction or toward the non-skin side rather than being absorbed by the skin side layer 21, making it easier to diffuse the excrement within 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.

[0163] 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 localized swelling of the absorbent core 20A at the portion where excrement is received on the skin side of the absorbent core 20A during wear, and thus reducing the risk of localized swelling of the diaper 1 after absorption being noticeable from the outside of clothing.

[0164] 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 to 23 (absorbent cores 21 to 24) are not limited to this. The absorbent core 20A may be formed of any material as long as it contains cellulose fibers and SAP. For example, the absorbent core 20A may be formed of three layers without the skin-side upper layer 24. Alternatively, the absorbent core 20A may be formed of a total of two layers: one layer containing a mixture of SAP and cellulose fibers, and one layer made of an SAP sheet. The absorbent core 20A may also be formed of a single layer containing cellulose fibers and a superabsorbent polymer.

[0165] 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 in any region. 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 to 23 at a position that directly receives a large amount of excreted liquid during excretion.

[0166] 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 further 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. Note that when an adhesive (adhesive layer) is disposed between the skin side layer 21 and the intermediate layer 22, the skin side upper layer 24 and the skin side layer 21 sandwiched between the adhesive layer between the skin side upper layer 24 and the core wrap sheet 25 and the adhesive layer between the skin side layer 21 and the intermediate layer 22 can be used as the interposed absorbent layer 20b.

[0167] In addition, in this embodiment, the core wrap sheet 25 and the core wrap sheet 26 are each provided as separate components, but the core wrap sheet 25 and the core wrap sheet 26 may be formed as an integrated component, and a single sheet component may be folded over to cover both the skin side and non-skin side of the absorbent core 20A.

[0168] DESCRIPTION OF SYMBOLS 1 Diaper (pants-type disposable diaper, absorbent article) 2 Side joint portion 10 Absorbent body 12 Top sheet (surface sheet) 13 Back sheet (back sheet) 13a Back sheet (liquid-impermeable sheet, back sheet) 13b Back sheet (exterior sheet, back sheet) 15 Leakage-barrier wall portion 16 Leakage-barrier wall elastic member 17 Leg gather elastic member 20 Absorbent body 20A Absorbent core 20b Intervening absorbent layer 201 Liquid-absorbent fiber (cellulose fiber) SAP Superabsorbent 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 Skin-side upper layer (absorbent core) 25 Core wrap sheet (skin side core wrap sheet portion), 26 Core wrap sheet (non-skin side core wrap sheet portion), 27 Nonwoven fabric (intermediate sheet), 30 Front waistline portion, 31 Skin side sheet, 32 Non-skin side sheet, 33 Waistline elastic member, 34 Cover sheet, 40 Rear waistline portion, 41 Skin side sheet, 42 Non-skin side sheet, 43 Waistline elastic member, 44 Cover sheet 50 Dot-like compressed portion m1, m2, m3, m4 Adhesive layer, F Folded portion, OR Outer region, IR Inner region

Claims

1. An absorbent article having an absorbent body which, in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction which are orthogonal to one another, and which comprises an absorbent core and a plurality of sheet portions including a skin-side core wrap sheet portion located closer to the skin than the absorbent core and a non-skin-side core wrap sheet portion located closer to the skin than the absorbent core, wherein the absorbent core comprises at least a superabsorbent polymer, and each of the plurality of sheet portions is composed of at least one of cellulose fiber and thermoplastic fiber having an average fiber diameter of 16.8 μm or less, and the absorbent body comprises a first adhesive layer, a second adhesive layer adjacent to the first adhesive layer in the thickness direction, and an intervening absorbent layer sandwiched between the first adhesive layer and the second adhesive layer and consisting of one or more absorbent layers, and the first adhesive layer and the second adhesive layer are two adhesive layers adjacent to each other in the thickness direction among the plurality of adhesive layers provided on the absorbent body, which adhesive layers make the intervening absorbent layer have the greatest thickness in its natural state, an absorbent layer different from the intervening absorbent layer provided on at least one of the outer sides of the first adhesive layer in the thickness direction and the outer sides of the second adhesive layer in the thickness direction; and a base area of the absorbent article is 150 cm when the absorbent article is folded in half at the center fold in the longitudinal direction. ２ an absorbent article in which a weight of 5 kg is placed on the absorbent article for 24 hours and then the weight is removed, the average thickness of the intervening absorbent layer immediately after the weight is removed is 2.0 mm or less, and when the thickness at the center in the width direction of the folded portion immediately after the weight is removed is defined as an immediate thickness and the thickness at the center in the width direction of the folded portion 72 hours after the weight is removed is defined as a 72-hour thickness, the value obtained by dividing the 72-hour thickness by the immediate thickness is 106.6% or less.

2. An absorbent article as described in claim 1, characterized in that, when the thickness of the absorbent article from which the weight has been removed is the thickness at the center of the width direction of the folded portion one week after the weight has been removed, the value obtained by dividing the thickness one week later by the thickness immediately after the weight has been removed is 112.2% or less.

3. An absorbent article according to claim 1 or 2, characterized in that the absorbent core has a basis weight lower than that of the surrounding area and has a low basis weight portion along the longitudinal direction.

4. An absorbent article as claimed in claim 1 or 2, wherein the absorbent layer has a first absorbent layer located closest to the skin in the thickness direction, and a second absorbent layer located further away from the skin than the first absorbent layer, and on one side in the width direction of the crotch part that is located between the crotch of the wearer when worn, the side edge of the second absorbent layer is located outside the side edge of the first absorbent layer, and the absorbent article has a portion where the skin-side core wrap sheet portion and the skin-side surface of the second absorbent layer are adhered.

5. An absorbent article as claimed in claim 1 or 2, wherein the absorbent layer has a first absorbent layer located on one side in the thickness direction and a second absorbent layer located on the other side of the first absorbent layer, and on one side in the longitudinal direction, the end on one side of the longitudinal direction of the second absorbent layer is located outside the end on one side of the longitudinal direction of the first absorbent layer, and the absorbent article has a portion where the other side surface in the thickness direction of the sheet portion located on one side in the thickness direction of the first absorbent layer is adhered to the one side surface in the thickness direction of the second absorbent layer.

6. An absorbent article as described in claim 1 or 2, characterized in that, when viewed in the thickness direction, it has a portion inside the outer shape of the absorbent core where the non-skin side of the skin-side core wrap sheet portion and the skin side of the non-skin side core wrap sheet portion are bonded.

7. An absorbent article as described in claim 1 or 2, wherein in the crotch area that is located under the wearer's crotch when worn, the absorbent core has a constricted portion on the inside in the width direction, and when viewed in the thickness direction, an adjacent area adjacent to the constricted portion from the outside in the width direction has a portion where the non-skin-side side of the skin-side core wrap sheet portion and the skin-side side of the non-skin-side core wrap sheet portion are bonded.

8. An absorbent article as claimed in claim 1 or 2, wherein a strip of adhesive is provided on the other surface of the sheet portion in the thickness direction, the average width of the strip of adhesive being smaller than the average particle size of the superabsorbent polymer, and when an area of the other surface of the sheet portion that is located outward from the outermost ends of the plurality of absorbent layers in the width direction is defined as an outer region, and an area of the other surface of the sheet portion that is located inward from the outermost ends of the plurality of absorbent layers in the width direction is defined as an inner region, the number of intersections of the strip of adhesive per unit area in the inner region is greater than the number of intersections of the strip of adhesive per unit area in the outer region.

9. An absorbent article as claimed in claim 1 or 2, wherein the sheet portion has an intermediate sheet between a plurality of the absorbent layers adjacent to each other in the thickness direction, the intermediate sheet being formed of at least one of cellulose fibres and thermoplastic fibres having an average fibre diameter of 16.8 μm or less, and the absorbent article is characterized in that the intermediate sheet has an intermediate adhesive layer provided with adhesive on at least one surface in the thickness direction.

10. An absorbent article according to claim 9, characterized in that the skin-side core wrap sheet portion or the non-skin-side core wrap sheet portion has a portion bonded to the intermediate sheet.

11. An absorbent article according to claim 1 or 2, characterized in that the absorbent body has compressed portions compressed in the thickness direction.

12. An absorbent article as described in claim 1 or 2, characterized in that the longitudinal length of the absorbent article in the folded state is 85.3% or more of half the longitudinal length of the absorbent article in the unfolded and stretched state.

13. An absorbent article as described in claim 1 or 2, characterized in that there is no elastic member that continuously traverses the absorbent core in the width direction from one end to the other end of the absorbent core in the width direction.

14. An absorbent article as described in claim 1 or 2, comprising a top sheet provided closer to the skin than the skin-side core wrap sheet portion, and a back sheet provided closer to the skin than the non-skin-side core wrap sheet portion, characterized in that the absorbent article has a portion where the top sheet and the back sheet are adhered.

15. An absorbent article according to claim 1 or 2, characterized in that the absorbent layer has an SAP layer in which the volume occupied by the superabsorbent polymer is greater than the volume occupied by the cellulose fibers.

16. An absorbent article according to claim 1 or 2, characterized in that the absorbent layer comprises cellulose fibers, and the absorbent layer has a pulp layer in which the volume occupied by the cellulose fibers is greater than the volume occupied by the superabsorbent polymer.

17. An absorbent article as claimed in claim 1 or 2, wherein the absorbent layer comprises cellulose fibers, and the absorbent layer has: an SAP layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers; and a pulp layer in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer, and wherein the average thickness of the pulp layer is 1.5 times or less the average thickness of the SAP layer.

18. An absorbent article as described in claim 1 or 2, wherein the absorbent layer comprises cellulose fibers, and the absorbent layer has: an SAP layer in which the volume occupied by the superabsorbent polymer is larger than the volume occupied by the cellulose fibers; and a pulp layer in which the volume occupied by the cellulose fibers is larger than the volume occupied by the superabsorbent polymer, the SAP layer and the pulp layer being adjacent in the thickness direction, and an adhesive being provided between the SAP layer and the pulp layer.

19. An absorbent article according to claim 1 or 2, characterized in that the thermoplastic fibers are polyethylene fibers, polypropylene fibers, or fibers consisting of a combination of the polyethylene fibers and the polypropylene fibers.

20. An absorbent article according to claim 1 or 2, wherein the absorbent core comprises cellulose fibers, and the density of the absorbent core is 0.2 g / cm ３ An absorbent article characterized by the above.

21. An absorbent article as described in claim 1 or 2, characterized in that one or more of the intervening absorbent layers that are located closer to the skin than the absorbent layer that is closest to the skin in the thickness direction do not contain nonwoven fabric.

22. An absorbent article as set forth in claim 1 or 2, characterized in that the absorbent layer of the intervening absorbent layer that is located closest to the skin in the thickness direction does not contain absorbent resin powder.

23. An absorbent article as claimed in claim 1 or 2, wherein the absorbent layer of the intervening absorbent layers that is closest to the skin in the thickness direction comprises the superabsorbent polymer, and the liquid permeation rate under load of the superabsorbent polymer in the absorbent layer that is closest to the skin exceeds 10 seconds.

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