Absorbent article

Abstract

Provided is an absorbent article (1) comprising an absorption layer (21) that contains a superabsorbent polymer (SAP), and a core wrap sheet (25) disposed on one thickness-direction side of the absorption layer (21). A strip-form adhesive is provided to the other-side surface on the other thickness-direction side of the core wrap sheet (25). The average width of the strip-form adhesive is less than the average particle diameter of the superabsorbent polymer (SAP). The number of intersection points of the adhesive per unit area in outer regions (OR) is less than the number of intersection points of the adhesive per unit area in an inner region (IR), where the outer regions (OR) are regions on the other-side surface of the core wrap sheet (25) that are positioned outside the outermost edges (21e) of the absorption layer (21) with respect to the width direction, and the inner region (IR) is a region positioned further inward than the outer edges (21e).

Description

absorbent articles

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

[0002]

[0003] Conventionally, absorbent articles have been known that include a so-called SAP sheet, which is formed into a sheet shape by enclosing a large number of superabsorbent polymer (SAP) particles in a base sheet (core wrap sheet). For example, Patent Literature 1 discloses a technology relating to an absorbent core (SAP sheet) that extends in both the transverse and longitudinal directions, and is formed into a substantially planar shape by enclosing an absorbent material such as SAP in a core wrap.

[0003] Special table 2017-518813 publication

[0004] In such SAP sheets, it has been common to form them into a flat shape by fixing the numerous SAP particles contained therein with an adhesive applied to the inner surface of the core wrap sheet. However, it is difficult for the adhesive to reach the numerous SAP particles that do not face the surface of the core wrap sheet, and the SAP sheet is prone to deformation due to misalignment of the SAP particles. On the other hand, if an attempt is made to suppress misalignment of the SAP particles by increasing the amount of adhesive applied to the core wrap sheet, there is a risk that the adhesive will seep out of the core wrap sheet.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide an absorbent body in which the SAP is resistant to crumbling while suppressing the bleeding of adhesive.

[0006] The main invention for achieving the above object is an absorbent article having an absorbent layer, which in an unfolded state has a longitudinal direction, a width direction, and a thickness direction that are perpendicular to each other and contains a superabsorbent polymer, and a core wrap sheet arranged on one side of the absorbent layer in the thickness direction, wherein a strip-shaped adhesive is provided on the other side of the core wrap sheet in the thickness direction, the average width of the strip-shaped adhesive is smaller than the average particle size of the superabsorbent polymer, and when an outer region is defined as a region of the other side of the core wrap sheet that is located outside the outermost edge of the absorbent layer in the width direction, and an inner region is defined as a region of the other side of the core wrap sheet that is located inside the outermost edge of the absorbent layer in the width direction, the number of intersections of the strip-shaped adhesive per unit area in the outer region is smaller than the number of intersections of the strip-shaped adhesive per unit area in the inner region. Other features of the absorbent article will be made clear by the description of this specification and the accompanying drawings.

[0007] According to the present invention, it is possible to provide an absorbent body in which the SAP is resistant to crumbling while suppressing the bleeding of the adhesive.

[0008] 7A and 7B are diagrams illustrating the configuration of a first adhesive discharging mechanism 140. FIG. 7B is a diagram illustrating the configuration of a second adhesive discharging mechanism 150. FIG. 7C is a diagram illustrating the configuration of a core wrap sheet 25. FIG. 7D is a diagram illustrating the configuration of a skin-side surface of the core wrap sheet 25. FIG. 7E is a photograph of a portion of the skin-side surface of the core wrap sheet 25 in the inner region IR, magnified 40 times. FIG. 7F is a photograph of a portion of the skin-side surface of the core wrap sheet 25 in the outer region OR, magnified 40 times. FIG. 7F is a diagram illustrating the measurement results of the particle size distribution of SAP. FIG. 7C is a diagram illustrating the configuration of a first adhesive discharging mechanism 140. FIG. 7D is a diagram illustrating the configuration of a second adhesive discharging mechanism 150. FIG. 7E is a diagram illustrating the configuration of a skin-side surface of the core wrap sheet 25 in the inner region IR, magnified 40 times. FIG. 7F is a photograph of a portion of the skin-side surface of the core wrap sheet 25 in the outer region OR, magnified 40 times. FIG. 7C is a diagram illustrating the measurement results of the particle size distribution of SAP. FIG. 7D is a diagram illustrating the configuration of a first adhesive discharging mechanism 140. FIG. 7F is a diagram illustrating the configuration of a second adhesive discharging mechanism 150.

[0009] The present specification and the accompanying drawings make at least the following clear: (Aspect 1) An absorbent article having an absorbent layer that, in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction that are orthogonal to one another and that contains a superabsorbent polymer, and a core wrap sheet arranged on one side of the absorbent layer in the thickness direction, wherein a strip-shaped adhesive is provided on the other surface of the core wrap sheet in the thickness direction, the average width of the strip-shaped adhesive is smaller than the average particle size of the superabsorbent polymer, and when an outer region is defined as a region of the other surface of the core wrap sheet that is located outward from the outermost edge of the absorbent layer in the width direction, and an inner region is defined as a region of the other surface of the core wrap sheet that is located inward from the outermost edge of the absorbent layer in the width direction, the number of intersections of the strip-shaped adhesive per unit area in the outer region is smaller than the number of intersections of the strip-shaped adhesive per unit area in the inner region.

[0010] According to the absorbent article of aspect 1, since the strip-shaped adhesive is provided with a width narrower than the SAP particle diameter, the adhesive easily penetrates into the gaps between the SAP particles, fixing the SAP particles together and preventing deformation. Furthermore, in the core wrap sheet, the coating density of the adhesive is reduced in the outer widthwise regions where no SAP particles are arranged so that the number of intersections between the adhesive is fewer than in the inner widthwise region where the SAP particles are arranged, thereby preventing the adhesive from seeping out.

[0011] (Aspect 2) The absorbent article according to aspect 1, wherein the minimum distance between the intersections of the strip-shaped adhesives is smaller than the average particle size of the superabsorbent polymer when swollen.

[0012] In the absorbent article of aspect 2, even when the SAP particles swell due to the absorption of excrement during use, the SAP particles are less likely to protrude from the mesh of the strip-shaped adhesive, making the absorbent layer (one-side absorbent layer) less likely to collapse.

[0013] (Aspect 3) The absorbent article according to aspect 1 or 2, wherein the minimum distance between the intersections of the strip-shaped adhesives is smaller than the average particle size of the superabsorbent polymer when not swollen.

[0014] According to the absorbent article of aspect 3, even before use, SAP particles are less likely to protrude from the mesh formed by the intersection of the numerous strip-shaped adhesives, which prevents, for example, the SAP from shifting position during distribution of the absorbent article, causing the absorbent layer (absorbent core) to collapse before use.

[0015] (Aspect 4) The absorbent article according to any one of aspects 1 to 3, wherein the thickness of the absorbent layer is greater than 1.5 times the average particle size of the superabsorbent polymer.

[0016] According to the absorbent article of aspect 4, by stacking at least 1.5 layers of SAP particles in the absorbent layer (absorbent core), water absorption and water retention can be improved compared to a single-layer absorbent core in which SAP particles are arranged in a plane.

[0017] (Aspect 5) The absorbent article according to any one of aspects 1 to 4, wherein at least a portion of the strip-shaped adhesive is present at a central position in the thickness direction of the absorbent layer.

[0018] According to the absorbent article of aspect 5, the adhesive penetrates into the absorbent layer, so that the SAP particles are less likely to become misaligned with each other, and the absorbent layer (absorbent core) is less likely to collapse.

[0019] (Embodiment 6) The absorbent article according to any one of embodiments 1 to 5, wherein the adhesive for fixing the superabsorbent polymer to the core wrap sheet has a residual stress of 2 KPa or more and 20 KPa or less.

[0020] According to the absorbent article of aspect 6, the adhesive that fixes the SAP particles has a resistance (residual stress) that is sufficient to prevent the SAP particles from falling off the core wrap sheet (base sheet) even when external forces are applied, thereby increasing the probability that the fixation rate of the SAP particles will be 40% or more, and making the absorbent layer (absorbent core) less likely to collapse.

[0021] (Aspect 7) An absorbent article described in any of aspects 1 to 6, having an intermediate sheet on the other side of the absorbent layer in the thickness direction, a strip of adhesive on one side of the intermediate sheet in the thickness direction, and the average width of the strip of adhesive on the other side of the core wrap sheet is smaller than the average width of the strip of adhesive on the one side of the intermediate sheet.

[0022] In the absorbent article of Aspect 7, the adhesive is not excessively applied to the skin-side (other side) surface of the core wrap sheet, which prevents the adhesive from seeping out to the non-skin-side surface of the core wrap sheet. On the other hand, if a larger amount of adhesive is applied to the non-skin-side (one side) surface of the intermediate sheet, a larger amount of adhesive is ejected toward the SAP particles, which more firmly bonds the SAP particles together and prevents the absorbent layer (absorbent core) from losing its shape.

[0023] (Aspect 8) An absorbent article described in any of aspects 1 to 6, having an intermediate sheet on the other side of the absorbent layer in the thickness direction, a strip of adhesive on one side of the intermediate sheet in the thickness direction, and the average width of the strip of adhesive on the other side of the core wrap sheet is larger than the average width of the strip of adhesive on the one side of the intermediate sheet.

[0024] In the absorbent article of Aspect 8, the amount of adhesive applied to the intermediate sheet is reduced, which makes it less likely that excreted fluid will be hindered from moving in the thickness direction of the intermediate sheet, thereby facilitating smooth transfer of excreted fluid to the absorbent layer provided on the non-skin side (one side) of the intermediate sheet in the thickness direction.

[0025] (Aspect 9) The absorbent article according to any one of aspects 1 to 8, wherein the absorbent layer has a low basis weight region that is a region having a predetermined width in the width direction and has a basis weight lower than that of the surrounding area.

[0026] According to the absorbent article of Aspect 9, excrement is absorbed less easily in the low basis weight regions than in other regions, and excrement is more likely to spread along the low basis weight regions. Therefore, even when a force that compresses the absorbent layer in the thickness direction is applied, for example, when the wearer assumes a sitting position while wearing the absorbent article, excrement can be easily drawn into the absorbent layer.

[0027] (Aspect 10) The absorbent article according to any one of aspects 1 to 9, wherein the average basis weight of the low basis weight region is greater than 0% and not more than 50% of the average basis weight of the region of the absorbent layer other than the low basis weight region.

[0028] According to the absorbent article of Aspect 10, by setting the average basis weight in the low basis weight region to 50% or less of the average basis weight of the other regions, the difference in average basis weight becomes larger than when the average basis weight is greater than 50%, making it easier to move liquids such as excrement along the low basis weight region. Furthermore, if the average basis weight in the low basis weight region is greater than 0%, at least the entire low basis weight region is prevented from being configured as a slit, making it easier to ensure the strength of the low basis weight region.

[0029] (Aspect 11) The absorbent article according to any one of aspects 1 to 10, wherein the minimum distance between intersections of the strip-shaped adhesives is smaller than the width of the low basis weight region.

[0030] According to the absorbent article of aspect 11, at least one intersection of adhesives is provided between both side edges of the low basis weight region, which facilitates fixation of SAP particles in the low basis weight region, and also increases the likelihood of adhesive being present at both side edges of the low basis weight region, thereby preventing the low basis weight region in the absorbent layer (absorbent core) from collapsing or being crushed.

[0031] (Aspect 12) The absorbent article according to any one of aspects 1 to 11, further comprising an intermediate sheet on the other side of the absorbent layer in the thickness direction, and a portion in the low basis weight region where the core wrap sheet and the intermediate sheet are joined in the thickness direction.

[0032] In the absorbent article of Aspect 12, if the core wrap sheet and the intermediate sheet are joined at least partially in the area where the low basis weight region is provided, the SAP particles are prevented from migrating across the low basis weight region. That is, each of the absorbent layers (absorbent cores) divided by the low basis weight region is more likely to independently maintain its shape. Therefore, the absorbent layer (absorbent core) as a whole is less likely to lose its shape.

[0033] (Aspect 13) The absorbent article according to any one of aspects 1 to 12, comprising an absorbent body including the absorbent layer and the core wrap sheet, and having intermittent regions in which the superabsorbent polymer is not provided at the front and rear end portions in the longitudinal direction of the absorbent body.

[0034] In the absorbent article of Aspect 13, because no SAP particles are disposed in the intermittent regions, the core wrap sheet is more likely to be directly bonded to a member (e.g., an intermediate sheet) disposed opposite the core wrap sheet in the thickness direction, which makes it difficult for the SAP particles constituting the absorbent layer (absorbent core) to protrude to both ends in the front-to-rear direction, and the absorbent layer is less likely to lose its shape.

[0035] (Aspect 14) The absorbent article according to any one of Aspects 1 to 13, wherein the average basis weight of the superabsorbent polymer in front of a center position in the longitudinal direction of the absorbent body is smaller than the average basis weight of the superabsorbent polymer in rear of the center position in the longitudinal direction of the absorbent body.

[0036] According to the absorbent article of aspect 14, by increasing the average basis weight of the SAP particles in the longitudinal front region located near the wearer's excretory opening when worn, excretory fluids such as urine can be more quickly absorbed, thereby suppressing urine leakage on the abdominal side.

[0037] (Aspect 15) The absorbent article according to any one of aspects 1 to 13, wherein the average basis weight of the superabsorbent polymer in front of a center position in the longitudinal direction of the absorbent body is equal to or greater than the average basis weight of the superabsorbent polymer in back of the center position in the longitudinal direction of the absorbent body.

[0038] According to the absorbent article of aspect 15, when worn, by increasing the average basis weight of the SAP particles in the longitudinal rear region located on the back side (buttocks side) of the wearer, it is possible to prevent excretory fluids such as urine from flowing around the buttocks to the back side and leaking out from the upper end of the back side.

[0039] (Aspect 16) The absorbent article according to any one of aspects 1 to 15, wherein a second absorbent layer containing the superabsorbent polymer and liquid-absorbent fibers is provided so as to be laminated with the absorbent layer in the thickness direction.

[0040] According to the absorbent article of aspect 16, the absorbent core has a laminated structure of two or more layers (an absorbent layer and a second absorbent layer), which improves water absorption and water retention capacity compared to an absorbent core having only one layer.

[0041] (Aspect 17) The absorbent article according to any one of aspects 1 to 16, wherein the second absorbent layer is disposed on the other side of the absorbent layer.

[0042] According to the absorbent article of Aspect 17, the second absorbent layer containing liquid-absorbent fibers that absorb water faster than the SAP particles is disposed on the skin side (other side) in the thickness direction, so that excreted liquid is quickly drawn from the skin side to the non-skin side and is easily retained in the absorbent layer disposed on the non-skin side, thereby improving the dryness of the skin side and making it less likely for the wearer to experience discomfort or annoyance.

[0043] (Aspect 18) The absorbent article according to any one of aspects 1 to 16, wherein the second absorbent layer is disposed on the one side of the absorbent layer.

[0044] According to the absorbent article of Aspect 18, the absorbent layer containing SAP particles, which have higher water retention than the liquid-absorbent fiber, is disposed on the non-skin side (one side) in the thickness direction, thereby increasing water retention on the skin side and making rewet less likely to occur, thereby making it less likely for the wearer to experience discomfort or an unpleasant feeling.

[0045] (Aspect 19) The absorbent article according to any one of aspects 1 to 18, wherein the core wrap sheet is made of a nonwoven fabric.

[0046] According to the absorbent article of Aspect 19, when an adhesive is applied or SAP particles are laminated while the nonwoven fabric is used as a base sheet and the base sheet is transported in the machine direction, the base sheet made of the nonwoven fabric is resistant to tearing, and therefore an absorbent body (absorbent core) with a stable shape can be formed. Furthermore, if the base sheet is transported while being sucked by a suction mechanism or the like, the SAP particles can be easily fixed on the base sheet.

[0047] (Aspect 20) An absorbent body having a longitudinal direction, a width direction, and a thickness direction that are perpendicular to each other, the absorbent body having a base sheet and a superabsorbent polymer laminated on the base sheet, the absorbent body having high basis weight regions in which the basis weight of the superabsorbent polymer is higher than that of surrounding areas, the high basis weight regions being arranged so that points of maximum thickness in the thickness direction are located intermittently in the longitudinal direction and the width direction, the maximum thickness is within 3 mm, and the distance between adjacent points of maximum thickness is 5 times or less the maximum thickness.

[0048] According to Aspect 20, high basis weight regions are arranged so that the points of maximum thickness in the thickness direction are located intermittently in the longitudinal and width directions, and low basis weight regions are formed around each high basis weight region. The low basis weight regions serve as folding points, making the absorbent body more easily deformable to conform to the contours of the wearer's body, improving fit. Furthermore, by having the maximum thickness of the absorbent body be 3 mm or less and the distance between adjacent points of maximum thickness be 5 times or less, it is possible to arrange multiple high basis weight regions and low basis weight regions while maintaining the absorbent body's thinness. Therefore, according to Aspect 20, an absorbent body containing a superabsorbent polymer can maintain its thinness while improving fit when worn.

[0049] (Aspect 21) The absorbent body according to aspect 20, wherein the maximum thickness is 2 mm or less, and the distance between adjacent points of maximum thickness is 4 times or less the maximum thickness.

[0050] According to Aspect 20, in an absorbent body containing a highly absorbent polymer, it is possible to improve the fit when worn while maintaining a thinner profile.

[0051] (Aspect 22) The absorbent body according to aspect 20, wherein the high basis weight region does not contain any fibrous material other than the superabsorbent polymer.

[0052] According to Aspect 22, it is possible to form a thinner absorbent body compared to an absorbent body containing a fibrous material.

[0053] (Aspect 23) The absorbent body according to aspect 20, wherein, in a plan view, the diameter of a circumscribing circle circumscribing each of the plurality of high basis weight regions is 2 mm or more and 4 mm or less.

[0054] According to aspect 23, by reducing the size of each of the multiple high basis weight regions in a planar view, a large number of high basis weight regions and low basis weight regions can be arranged on the base sheet, making it easier for the absorbent body to deform in accordance with the contours of the wearer's body, thereby improving fit.

[0055] (Aspect 24) The absorbent body according to aspect 20, characterized in that it has a low basis weight laminated region in which the superabsorbent polymer is laminated between adjacent points of maximum thickness, and a non-laminated region in which the superabsorbent polymer is not present between another adjacent points of maximum thickness.

[0056] According to Aspect 24, the low basis weight region that serves as the folding starting point has a low basis weight laminated region that can absorb and retain excrement, and a non-laminated region that is more easily bent due to the absence of superabsorbent polymer. Therefore, even in the low basis weight region, it is possible to achieve both ease of deformation that conforms to the unevenness of the wearer's body and the ability to absorb and retain excrement.

[0057] (Aspect 25) The absorbent body according to Aspect 24, characterized in that the low basis weight laminated regions are arranged intermittently in the longitudinal direction and the width direction, and the non-laminated regions are arranged intermittently in the longitudinal direction and the width direction.

[0058] According to aspect 25, by sparsely arranging low basis weight laminated areas and non-laminated areas in a plane, it is possible to provide a fabric that is easily deformable to conform to the contours of the wearer's body and has the ability to absorb and retain excretory fluids in a planar manner.

[0059] (Aspect 26) The absorbent body according to aspect 25, wherein, in a plan view, the largest diameter of the diameters of the inscribed circles inscribed in each of the plurality of non-laminated regions is equal to or smaller than the maximum thickness.

[0060] According to Aspect 26, by reducing the size in plan view of the non-laminated region where there is no superabsorbent polymer, leakage of excreted liquid through the non-laminated region can be suppressed.

[0061] (Aspect 27) The absorbent body according to aspect 26, characterized in that the number of low basis weight laminated regions is different in each of the three equal regions divided in the longitudinal direction, or the number of non-laminated regions is different in each of the three equal regions divided in the longitudinal direction.

[0062] According to aspect 27, by randomly arranging the low basis weight laminated regions and non-laminated regions in a plane, the absorbent body can more easily deform to conform to the contours of the wearer's body, thereby improving fit.

[0063] (Aspect 28) An absorbent body according to aspect 25, characterized in that, among the points of maximum thickness, the number of points at which the non-laminated region is located adjacent to one or the other side in the width direction is greater than the number of points at which the non-laminated region is located adjacent to one or the other side in the longitudinal direction.

[0064] According to Aspect 28, it is possible to prevent the absorbent body from losing flexibility in the width direction when in a swollen state.

[0065] (Aspect 29) The absorbent body according to aspect 20, further comprising another sheet positioned so as to sandwich the superabsorbent polymer between the base sheet and the other sheet, and characterized in that the absorbent body has a bonded region where the base sheet and the other sheet are bonded between adjacent points of maximum thickness, and a non-bonded region where the base sheet and the other sheet are not bonded between other adjacent points of maximum thickness.

[0066] According to aspect 29, by having a bonded region that serves as the folding starting point and a non-bonded region where a superabsorbent polymer can be placed between the base sheet and another sheet, it is possible to achieve both ease of deformation to conform to the contours of the wearer's body and the ability to absorb and retain excrement.

[0067] (Aspect 30) The absorbent body according to aspect 20, wherein a difference between the highest point and the lowest point in the thickness direction on one surface side of the base sheet is different from the difference on the other surface side of the base sheet.

[0068] According to Aspect 30, an absorbent body having properties suited to the purpose can be formed.

[0069] (Aspect 31) The absorbent body according to aspect 30, characterized in that it has a non-laminated region on one side of the base sheet between adjacent points of maximum thickness where the superabsorbent polymer is not present, and in plan view, the largest diameter of the diameters of the inscribed circles inscribed in each of the multiple non-laminated regions is less than the difference on the one side.

[0070] According to Aspect 31, by reducing the size in plan view of the non-laminated region where there is no superabsorbent polymer, leakage of excreted liquid through the non-laminated region can be suppressed.

[0071] (Aspect 32) The absorbent body according to aspect 30, characterized in that the weight of the superabsorbent polymer layered below the highest point on one side of the base sheet is 50% or more of the weight of the superabsorbent polymer layered over the entire base sheet.

[0072] According to Aspect 32, a desired weight of superabsorbent polymer can be layered in the recessed areas of the base sheet to form high basis weight areas in appropriate locations.

[0073] (Aspect 33) The absorbent body according to aspect 30, characterized in that when the region below the midpoint between the highest point and the lowest point is defined as a recessed region, the total length of the recessed regions, in a planar view, on an imaginary line passing through the centers of the recessed regions along the longitudinal direction, is 50% or more of the length of the entire base sheet.

[0074] According to Aspect 33, by laminating the superabsorbent polymer in desired areas of the base sheet, high basis weight areas and low basis weight areas can be formed at appropriate positions.

[0075] (Aspect 34) The absorbent body according to aspect 30, characterized in that when the region below the midpoint between the highest point and the lowest point is defined as a recessed region, in a planar view, the total length of the recessed regions on an imaginary line passing through the centers of the recessed regions along the width direction is 50% or more of the length of the entire base sheet.

[0076] According to Aspect 34, high-basis-weight regions and low-basis-weight regions can be formed at appropriate positions by laminating a superabsorbent polymer in desired regions of the base sheet.

[0077] 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.

[0078] <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.

[0079] 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 a direction along the stretch direction of the elastic threads 33, 43 of the front waist portion 30 and the rear waist portion 40. The vertical direction is a direction perpendicular to the stretch direction.

[0080] 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.

[0081] 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 each other. The longitudinal direction is along the longitudinal direction of the absorbent main body 10 and along the vertical direction of the pants-type diaper 1. The thickness direction is the direction in which the materials constituting the diaper 1 are layered, as shown in Fig. 3. In the thickness direction, the side that contacts the wearer's skin is referred to as the skin side, and the opposite side is referred to as the non-skin side. In the unfolded state, the front waistband 30 and the rear waistband 40 are aligned parallel to each other with a gap in the longitudinal direction, with the absorbent main body 10 spanning between them, with each longitudinal end of the absorbent main body 10 bonded and fixed to the skin side of the nearest waistband 30, 40, resulting in a generally H-shaped external shape in a plan view. From this state, the absorbent main body 10 is folded in half along the longitudinal center line CL. In this folded state, the opposing front waistline portion 30 and rear waistline portion 40 are joined and connected at both widthwise sides 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.

[0082] The absorbent main body 10 has an absorbent body 20 (details will be described later), a liquid-permeable top sheet 12 arranged closer to the skin than the absorbent body 20, and a back sheet 13 arranged closer to the skin than the absorbent body 20. The back sheet 13 has a two-layer structure consisting of a liquid-impermeable sheet 13a and a hydrophobic exterior sheet 13b arranged on the far side of the liquid-impermeable sheet 13a. However, the absorbent main body 10 may also include sheet members other than these. For example, a second sheet (not shown) may be provided between the top sheet 12 and the absorbent body 20 in the thickness direction.

[0083] A pair of leakage preventing walls 15 is provided along the longitudinal direction of the absorbent main body 10 on both widthwise sides of the absorbent main body 10. In Figure 3, a part of the exterior sheet 13b extends outward from both ends of the absorber 20 in the widthwise direction and is folded toward the skin at multiple locations to form the pair of leakage preventing walls 15. A leakage preventing wall elastic member 16 such as rubber thread is attached to the tip of the leakage preventing wall 15 in a state stretched along the longitudinal direction of the absorbent main body 10, so that the leakage preventing wall 15 can stand up toward the skin. In addition, leg elastic members 17 such as rubber thread are attached to both widthwise sides of the absorbent main body 10 in a state stretched along the longitudinal direction of the absorbent main body 10.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] <Regarding the absorbent body 20> Fig. 4 is a schematic cross-sectional view of the absorbent body 20. Fig. 5 is a plan view of the absorbent cores 21 to 23 stacked together. In Fig. 4, one side in the thickness direction is the non-skin side, and the other side in the thickness direction is the skin side.

[0088] As shown in FIG. 4 , the absorbent body 20 has absorbent cores 21-23 and an intermediate sheet 26 between a core wrap sheet 25 on one side (non-skin side) and a core wrap sheet 24 on the other side (skin side) in the thickness direction. The absorbent cores 21-23 are components that absorb and retain excretory fluids such as urine, and include a liquid-absorbent fiber 201 and a super absorbent polymer. The liquid-absorbent fiber 201 and the super absorbent polymer (hereinafter also referred to as SAP) are not particularly limited as long as they are usable as absorbent cores for absorbent articles. For example, examples of the liquid-absorbent fiber 201 include wood pulp fibers, non-wood pulp fibers such as bagasse, kenaf, bamboo, hemp, and cotton, regenerated cellulose fibers such as rayon fibers, and semi-synthetic fibers such as acetate fibers. Examples of SAP include starch-based, cellulose-based, and synthetic polymer-based polymer absorbents. The core wrap sheets 24, 25 and the intermediate sheet 26 are liquid-permeable sheets, examples of which include tissue and nonwoven fabric.

[0089] The absorbent cores 21-23 have, in order from one side (non-skin side) to the other side (skin side) in the thickness direction, a one-side absorbent layer 21, an intermediate absorbent layer 22, and an other-side absorbent layer 23. The one-side absorbent layer 21 and the other-side absorbent layer 23 are layers in which the volume occupied by SAP is larger than the volume occupied by liquid-absorbent fibers 201. The intermediate absorbent layer 22 is a layer in which the volume occupied by liquid-absorbent fibers 201 is larger than the volume occupied by SAP. In FIG. 4 , the other-side absorbent layer 23 and the intermediate absorbent layer 22 are integrally formed so as to be adjacent to each other in the thickness direction, whereas the one-side absorbent layer 21 is spaced from the intermediate absorbent layer 22 and the other-side absorbent layer 23 by an intermediate sheet 26. Also, in FIG. 4 , of the other-side absorbent layer 23 and the intermediate absorbent layer 22 which are integrally formed, the other-side absorbent layer 23 is mainly composed of SAP, and the intermediate absorbent layer 22 is mainly composed of liquid-absorbent fibers 201. That is, the other absorbent layer 23 and the intermediate absorbent layer 22 are configured as layers of different types. Alternatively, the intermediate absorbent layer 22 and the other absorbent layer 23 may be configured in a state in which the SAP and the liquid-absorbent fiber 201 are uniformly mixed. That is, the intermediate absorbent layer 22 and the other absorbent layer 23 may be formed as layers of the same type.

[0090] The one-side absorbent layer 21 is formed in a generally rectangular shape in plan view as shown in FIG. 5, and has a basis weight of the absorbent core (i.e., the total basis weight of the liquid-absorbent fiber 201 and the SAP: g / m ２ 5, two low basis weight regions 211 are provided along the longitudinal direction on both sides of the center position CW in the width direction. These low basis weight regions 211 divide the one absorbent layer 21 into three divided regions 21a to 21c. The provision of the low basis weight region 211 in the one absorbent layer 21 facilitates the movement of excrement, such as urine, in the thickness direction and longitudinal direction of the one absorbent layer 21, making it easier for the SAP to retain excrement and other liquids over a wide range of the one absorbent layer 21.

[0091] The low basis weight region 211 may be a slit penetrating the one absorbent layer 21 in the thickness direction. In this case, it is possible to easily and efficiently diffuse liquid such as excreted liquid over a wide area of ​​the low basis weight region 211. However, liquid-absorbent fibers 201 or SAP may be present in the low basis weight region 211 of the one absorbent layer 21. Alternatively, the low basis weight region 211 may be a region in which a portion of the one absorbent layer 21 is recessed in the thickness direction.

[0092] The intermediate absorbent layer 22 and the other absorbent layer 23 are integrally formed and have the same planar shape. In this embodiment, as shown in Fig. 5 , they are formed in a generally hourglass shape with constricted portions 222, 232 constricted inward in the width direction at the longitudinal center. Also, as shown in Fig. 5 , a portion of the one absorbent layer 21 extends outward in the width direction beyond the constricted portions 222, 232 of the intermediate absorbent layer 22 and the other absorbent layer 23. This configuration allows the constricted portions 222, 232 to reduce discomfort when the wearer opens and closes their legs, while SAP can be disposed outside the narrow constricted portions 222, 232 of the intermediate absorbent layer 22 and the other absorbent layer 23. This improves the fit around the crotch area of ​​the wearer while suppressing side leakage of excrement.

[0093] As with the one-side absorbent layer 21, at least one of the intermediate absorbent layer 22 and the other-side absorbent layer 23 has a basis weight of the absorbent core (total basis weight of the liquid absorbent fiber 201 and the SAP: g / m ２) is preferably a low-basis weight region. As shown in FIG. 4 , in the absorbent body 20 of this embodiment, both the intermediate absorbent layer 22 and the other absorbent layer 23 have low-basis weight regions 221, 231. When a wearer excretes fluid into the diaper 1 and the other absorbent layer 23 provided on the skin side receives the excreted fluid, the excreted fluid is quickly drawn from the low-basis weight region 231 into the absorbent body 20 (the intermediate absorbent layer 22). The intermediate absorbent layer 22 has a high volumetric ratio of liquid-absorbent fibers 201, which absorb fluid faster than SAP. Therefore, excreted fluid that migrates from the low-basis weight region 231 to the intermediate absorbent layer 22 is quickly and temporarily absorbed by the intermediate absorbent layer 22. Furthermore, the other absorbent layer 23 has a high volumetric ratio of SAP, which absorbs fluid slowly. Therefore, even in regions of the other absorbent layer 23 other than the low-basis weight region 231, excreted fluid is likely to migrate to the intermediate absorbent layer 22 before being absorbed by the SAP of the other absorbent layer 23.

[0094] Thereafter, the excreted liquid absorbed between the fibers of the liquid-absorbent fibers 201 of the intermediate absorbent layer 22 gradually migrates by gravity to the one-side absorbent layer 21. The volume occupancy of SAP is high in the one-side absorbent layer 21. Therefore, the excreted liquid is firmly absorbed and held by the SAP of the one-side absorbent layer 21. In this way, the absorbent body 20 of this embodiment can quickly draw and hold excreted liquid from the skin side to the non-skin side of the absorbent cores 21-23.

[0095] The comparison of the volumes occupied by the liquid-absorbent fibers 201 and the SAP in each layer of the absorbent cores 21-23 can be confirmed by a known method. For example, with the diaper 1 in a natural, dry state where 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 three layers 21-23 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 fibers 201 and the SAP are identified in the photographed cross-sectional image. Then, in the cross-sectional image, it is confirmed that the one-side absorbent layer 21, in which the area occupied by the SAP is larger than the area occupied by the liquid-absorbent fibers 201, the intermediate absorbent layer 22, in which the area occupied by the liquid-absorbent fibers 201 is larger than the area occupied by the SAP, and the other-side absorbent layer 23, in which the area occupied by the SAP is larger than the area occupied by the liquid-absorbent fibers 201, are layered in this order from one side (the side opposite to the skin) in the thickness direction. If the above is confirmed, these are designated as the absorbent cores 21 to 23 of this embodiment. Preferably, it is desirable to confirm that the three layers 21 to 23 are layered in cross-sectional images taken at multiple locations in the longitudinal direction of the absorbent body 20. Furthermore, based on the captured cross-sectional images, it can also be confirmed that the one-side absorbent layer 21 has a low basis weight region 211 and that the low basis weight region 211 is a slit.

[0096] <Regarding Formation of Absorbent Body 20> Next, an outline of a method for forming the absorbent body 20 will be described. Here, a method for mainly forming the one-side absorbent layer 21 of the absorbent body 20 will be described. Figure 6 is a diagram schematically showing a part of an absorbent body forming apparatus 100 that forms the absorbent body 20. The absorbent body forming apparatus 100 has a conveying mechanism 110 that conveys a base sheet in a conveying direction, a particle supplying mechanism 120 that supplies superabsorbent polymer (SAP) particles toward the base sheet, and a first adhesive discharging mechanism 140 to a third adhesive discharging mechanism 160 that discharge an adhesive toward the base sheet together with an airflow.

[0097] In the following description, the conveyance direction in which the base sheet is conveyed is also referred to as the “MD direction,” and the direction perpendicular to the MD direction (the depth direction of the paper in FIG. 6 ) is also referred to as the “CD direction.” In this embodiment, the MD direction is the direction along the longitudinal direction of the absorbent body 20, and the CD direction is the direction along the width direction of the absorbent body 20.

[0098] The absorbent forming apparatus 100 transports a core wrap sheet continuous body 25a, which is made up of core wrap sheets 25 continuous in the longitudinal direction, in the MD direction as a base sheet, and produces an absorbent core 21 (one-side absorbent layer 21) by layering superabsorbent polymer (SAP) particles on the core wrap sheet continuous body 25a (base sheet).

[0099] The transport mechanism 110 includes a transport conveyor, multiple transport rollers, etc. The transport rollers may be drive rollers driven to rotate by a drive source such as a motor, or driven rollers that rotate without a drive source. The transport conveyor is preferably a suction belt conveyor, with the upper surface of a rotating endless belt as the transport surface, and transporting the base sheet while suctioning it using multiple air intake holes (not shown) provided on the transport surface. In this embodiment, as shown in FIG. 6 , the transport surface of the transport mechanism 110 is inclined at a predetermined angle θ with respect to the horizontal plane so that the downstream side in the MD direction is lowered. This makes it easier for the SAP particles supplied from the particle supply mechanism 120 (described later) to move downstream due to gravity when they bounce off the surface of the base sheet, thereby reducing the likelihood of the SAP particles being placed in unintended positions.

[0100] The first adhesive dispensing mechanism 140 dispenses an adhesive, such as a hot melt adhesive (HMA), onto a predetermined region of the core wrap sheet continuous web 25a (base sheet) being conveyed in the MD direction. Figures 7A and 7B are diagrams illustrating the configuration of the first adhesive dispensing mechanism 140. The first adhesive dispensing mechanism 140 is disposed vertically above the conveying surface on which the base sheet is conveyed and includes multiple adhesive dispensing units 141. Each adhesive dispensing unit 141 has multiple dispensing nozzles 142 that dispense adhesive toward the base sheet, arranged at predetermined intervals along the CD direction as shown in Figure 7B. The region of the adhesive dispensing unit 141 in the CD direction where the dispensing nozzles 142 are provided is referred to as an adhesive dispensing region 141f. In other words, the adhesive dispensing region 141f represents the range in the CD direction in which the adhesive dispensing unit 141 can dispense adhesive. The adhesive discharged from the discharge nozzle 142 is stretched into fibers (i.e., thin strips) by the air sprayed from the discharge nozzle 142, and lands on the base sheet in a spiral or Ω shape. On the other hand, no discharge nozzles 142 are provided at either end in the CD direction of the adhesive discharge section 141, and no adhesive is discharged from these ends. Hereinafter, the areas at either end in the CD direction where no discharge nozzles 142 are provided are referred to as adhesive non-discharge areas 141n.

[0101] The adhesive discharge sections 141 are aligned in the CD direction to form an adhesive discharge array. In Fig. 7A, the first adhesive discharge mechanism 140 is made up of a first adhesive discharge array 140A with four adhesive discharge sections 141 aligned, and a second adhesive discharge array 140B with five adhesive discharge sections 141 aligned. However, the number of adhesive discharge sections 141 that make up the adhesive discharge arrays 140A and 140B is not limited to this and can be adjusted as appropriate depending on the width of the adhesive discharge range in the CD direction.

[0102] The adhesive discharge sections 141 constituting the first adhesive discharge row 140A and the adhesive discharge sections 141 constituting the second adhesive discharge row 140B are arranged to be offset from each other in the CD direction, as shown in Figure 7A. Specifically, they are arranged so that their non-adhesive discharge regions 141n do not overlap in the CD direction. By discharging adhesive from each of the adhesive discharge regions 141f of the first adhesive discharge row 140A and the second adhesive discharge row 140B onto the base sheet being transported in the MD direction, it is possible to prevent the formation of regions on the base sheet in the CD direction where no adhesive is applied.

[0103] In this embodiment, the region in the center in the CD direction where the adhesive discharge regions 141f of the first adhesive discharge array 140A and the second adhesive discharge array 140B overlap is referred to as the central region CR. Furthermore, the regions on both sides in the CD direction where the adhesive discharge regions 141f of the first adhesive discharge array 140A and the second adhesive discharge array 140B do not overlap are referred to as the edge regions SR. As shown in Figure 7A, in the central region CR, adhesive is discharged from the adhesive discharge regions 141f of the first adhesive discharge array 140A and the second adhesive discharge array 140B, whereas in the edge regions SR, adhesive is discharged only from the adhesive discharge regions 141f provided at both ends of the second adhesive discharge array 140B. Therefore, the amount of adhesive discharged per unit area in the edge regions SR is smaller than in the central region CR.

[0104] Returning to FIG. 6 , after the first adhesive dispensing mechanism 140 applies adhesive to a predetermined region of the base sheet (core wrap sheet continuous body 25a), SAP particles are supplied to the base sheet from the particle supplying mechanism 120, located downstream in the MD direction from the first adhesive dispensing mechanism 140. The particle supplying mechanism 120 supplies the SAP particles toward the base sheet by gravity or by discharging them with pressurized air. The SAP particles that reach the base sheet are deposited on the adhesive applied by the first adhesive dispensing mechanism 140 to form the first absorbent layer 21 (absorbent core 21). Note that when the base sheet is transported by a suction belt conveyor, the supplied SAP particles are also more likely to remain on the base sheet due to the suction of the conveyor, making it less likely to become displaced. In this embodiment, the particle supplying mechanism 120 supplies the SAP particles to the central region CR in the CD direction (see FIG. 7A ). That is, the first absorbent layer 21 is formed in a region that overlaps with the central region CR in the CD direction. The reason for this will be explained later.

[0105] Next, adhesive is dispensed onto the base sheet from a second adhesive dispensing mechanism 150 disposed downstream in the MD direction of the particle supplying mechanism 120, onto the SAP particles (one-side absorbent layer 21) accumulated in a predetermined region of the base sheet. FIG. 8 illustrates the configuration of the second adhesive dispensing mechanism 150. The second adhesive dispensing mechanism 150 has substantially the same configuration and function as the first adhesive dispensing mechanism 140. Specifically, the second adhesive dispensing mechanism 150 includes adhesive dispensing units 151, 151... each equipped with a plurality of adhesive dispensing nozzles (see FIG. 7B , not shown in FIG. 8 ). Each adhesive dispensing unit 151 includes an adhesive dispensing region 151f in the CD where the adhesive dispensing nozzles are provided, and an adhesive non-dispensing region 151n where no adhesive dispensing nozzles are provided. The adhesive dispensing units 151 are arranged side by side in the CD, forming adhesive dispensing arrays 150A and 150B, and adhesive is dispensed onto the base sheet from each adhesive dispensing region 151f.

[0106] Furthermore, the region in the central portion in the CD direction where the adhesive discharge regions 151f of the first adhesive discharge row 150A and the second adhesive discharge row 150B overlap is referred to as a central region CR, and the regions at both ends in the CD direction where the adhesive discharge regions 151f of the first adhesive discharge row 150A and the second adhesive discharge row 150B do not overlap are referred to as edge regions SR. In this case, the amount of adhesive discharged per unit area in the central region CR is greater than the amount of adhesive discharged per unit area in the edge regions SR. In other words, more adhesive is discharged onto the SAP particles (one-side absorbent layer 21) that overlap the central region CR than onto the edge regions SR.

[0107] Next, adhesive is dispensed from the third adhesive dispensing mechanism 160 toward the base sheet (and the one-side absorbent layer 21) (see FIG. 6 ). The third adhesive dispensing mechanism 160 is provided downstream in the MD direction from the second adhesive dispensing mechanism 150, and has substantially the same function and configuration as the second adhesive dispensing mechanism 150. That is, the third adhesive dispensing mechanism 160 dispenses more adhesive onto the SAP particles (one-side absorbent layer 21) that overlap the central region CR in the CD direction than onto the edge region SR.

[0108] Next, downstream in the MD direction of the third adhesive discharging mechanism 160, a continuous intermediate sheet 26a, which is made up of a continuous intermediate sheet 26 in the longitudinal direction, is supplied from above the SAP particles (one-side absorbent layer 21). The supplied continuous intermediate sheet 26a is bonded to the base sheet (continuous core wrap sheet 25a) and the SAP particles (one-side absorbent layer 21) via an adhesive, thereby forming an absorbent core 21 in which the SAP particles (one-side absorbent layer 21) are sandwiched between the core wrap sheet 25 and the intermediate sheet 26 in the thickness direction.

[0109] Although not shown in Figure 6, a continuous body of adhesive, liquid-absorbent fiber 201, SAP, adhesive, and core wrap sheet 24 is further supplied to the absorbent core 21 (base sheet) transported in the MD direction, thereby forming an absorbent body 20 having a laminated structure as shown in Figure 4.

[0110] As described above, the absorbent core 21 (one-side absorbent layer 21) of this embodiment is formed by sandwiching SAP particles between base sheets (core wrap sheet 25 and intermediate sheet 26) in the thickness direction. Conventionally, when forming such an absorbent core, it has been common to apply an adhesive to the inner surface of the base sheet sandwiching the SAP particles and fix the SAP particles with the adhesive. However, with this method, SAP particles positioned opposite the adhesive-coated base sheet are in direct contact with the adhesive and firmly fixed, whereas SAP particles positioned away from the base sheet in the thickness direction are not in contact with the adhesive and are therefore less likely to be fixed. That is, among the SAP particles (SAP layer) stacked in the thickness direction, the adhesive is easily attached to the SAP particles positioned adjacent to the base sheet (adhesive) on both sides in the thickness direction, but the adhesive is less likely to reach the SAP particles positioned in the center in the thickness direction. As a result, the relative positions of the SAP particles in the center in the thickness direction are easily shifted, which may cause the absorbent core to lose its shape.

[0111] Furthermore, if the amount of adhesive applied to the inner surface of the base sheet is increased in order to prevent the SAP particles from shifting position, the adhesive may seep out to the outside of the base sheet (the skin-side or non-skin-side surface of the absorbent body 20), which may cause discomfort to the user or deteriorate the absorption performance.

[0112] In contrast, in this embodiment, the average width of the adhesive discharged in a strip-like (fibrous) shape from the first adhesive dispensing mechanism 140 to the third adhesive dispensing mechanism 160 is smaller than the average particle size of the SAP particles, making it easier for the adhesive to penetrate between the SAP particles. Specifically, the average width of the strip-like adhesive is 0.016 to 0.018 mm, while the average particle size of the SAP particles is 0.3 to 0.4 mm (see FIG. 10 ). Furthermore, in this embodiment, the second adhesive dispensing mechanism 150 and the third adhesive dispensing mechanism 160 discharge the adhesive directly toward the SAP particles deposited on the base sheet (see FIG. 6 ). Therefore, the thin strip-like adhesive easily moves from one side to the other in the thickness direction while penetrating between adjacent SAP particles, making it easier for the adhesive to reach each SAP particle. This makes it easier for the SAP particles to be fixed together, preventing the absorbent core from losing its shape.

[0113] 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.

[0114] FIG. 12 shows an example of the measurement results of SAP particle size distribution. This figure shows the particle size distribution of SAP measured based on the shaking test described above for two types of SAP (both commercially available) that can be used for absorbent cores, Samples A and B. For example, if the shaking test for Sample A shows that the distribution of SAP remaining on the No. 4 sieve (355 μm mesh) is 48.3%, then 48.3% of the SAP in Sample A has a particle size distribution of 355 to 500 μm. From this data, the average particle size of the SAP can be determined. Alternatively, the SAP particle size may be calculated from a magnified microscope image such as that shown in FIG. 10 without using such a shaking test.

[0115] Furthermore, in this embodiment, the amount of adhesive dispensed per unit area in the region of the base sheet (core wrap sheet 25) to which SAP particles are supplied is less than the amount of adhesive dispensed per unit area in the region to which SAP particles are not supplied. For example, as described in Fig. 7 , the first adhesive dispensing mechanism 140 dispenses adhesive from two adhesive dispensing arrays, the first adhesive dispensing array 140A and the second adhesive dispensing array 140B, in the central region CR in the CD direction, while dispensing adhesive from only the second adhesive dispensing array 140B in the edge region SR in the CD direction. Then, SAP particles are supplied to the central region CR by the particle supply mechanism 120.

[0116] FIG. 9 is a plan view illustrating the regions of the core wrap sheet 25 where SAP particles and adhesive are provided. FIG. 9 illustrates the core wrap sheet 25 in an expanded and stretched state as viewed from the skin side (other side) in the thickness direction. In the hatched divided regions 21a-21b of the core wrap sheet 25 (skin side) in FIG. 9 , SAP particles are provided to form one-side absorbent layers 21 (absorbent cores 21). The region of the core wrap sheet 25 located inside the outermost ends 21es, 21es of the one-side absorbent layer 21 in the width direction is referred to as the inner region IR. The region of the core wrap sheet 25 located outside the outermost ends 21es, 21es of the one-side absorbent layer 21 in the width direction is referred to as the outer region OR. As described above, in this embodiment, the inner region IR is formed by supplying SAP particles to the central region CR, and therefore, the inner region IR coincides with the central region CR described in FIG. 7A at least in the CD direction. Similarly, since the outer region OR is formed by not supplying SAP particles to the edge region SR, the outer region OR coincides with the edge region SR described in Fig. 7A at least in the CD direction. However, the positions of the inner region IR (outer region OR) and the central region CR (edge ​​region SR) do not need to coincide perfectly, and they may be slightly misaligned in the CD direction. For example, the position of the outer edge 21es of the one absorbent layer 21 may be shifted outward or inward from the boundary between the central region CR and edge region SR in the CD direction.

[0117] Figure 10 is a photograph of a portion of the skin side of the core wrap sheet 25 in the inner region IR, magnified 40 times. Figure 11 is a photograph of a portion of the skin side of the core wrap sheet 25 in the outer region OR, magnified 40 times. It can be seen that multiple strip-shaped (fibrous) adhesive and SAP particles are arranged in the inner region IR in Figure 10. On the other hand, multiple strip-shaped (fibrous) adhesive are arranged in the outer region OR in Figure 11, but no SAP particles are arranged. Furthermore, since a nonwoven fabric is used as the core wrap sheet 25 in Figures 10 and 11, embossments formed during the production of the nonwoven fabric are also arranged.

[0118] 10, the width of the strip-shaped (fibrous) 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.

[0119] It can also be seen that the amount of strip-shaped adhesive applied per unit area (i.e., coating density) is lower in Figure 11 compared to Figure 10. That is, the number of intersections between strip-shaped (fibrous) adhesives per unit area in the outer region OR (see Figure 11) is lower than the number of intersections between strip-shaped (fibrous) adhesives per unit area in the inner region IR (see Figure 10). In this way, by lowering the coating density of the adhesive applied to the core wrap sheet 25 in the outer region OR where SAP particles are not disposed compared to the inner region IR where SAP particles are disposed, the adhesive is prevented from seeping out to the outside (non-skin side) of the core wrap sheet 25. On the other hand, by increasing the coating density of the adhesive that secures the SAP particles to each other in the inner region IR, it is possible to reduce the likelihood of misalignment of the SAP particles.

[0120] 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 10 and 11 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.

[0121] FIG. 10 also shows an image of the skin-facing side of the core wrap sheet 25 in the inner region IR of the diaper 1 before use. That is, FIG. 10 illustrates the state before the SAP particles swell due to absorption of liquids such as excrement. In this state, the minimum distance between the intersections of the strip-shaped adhesive is smaller than the particle size (average particle size) of the SAP particles. For example, the distance di between the intersections of a certain strip-shaped adhesive shown in FIG. 10 is clearly smaller than the diameter Dsap of a certain SAP. Therefore, SAP particles are less likely to protrude from the mesh formed by the intersections of multiple strip-shaped adhesives. This helps prevent the one-side absorbent layer 21 from losing its shape. For example, when the diaper 1 is manufactured in a manufacturing factory and distributed to the market, this prevents the one-side absorbent layer 21 (absorbent core) from collapsing before use due to misalignment of the SAP during distribution.

[0122] Furthermore, when the diaper 1 is in use, the SAP particles absorb excrement and other liquids and swell, so the particle size (average particle size) of the SAP particles becomes even larger than the diameter Dsap shown in Fig. 10. In other words, the minimum distance between the intersections of the strip-shaped adhesive is smaller than the particle size (average particle size) of the SAP particles when swollen. Therefore, even when the SAP swells after absorbing excrement during use of the diaper 1, the SAP particles are less likely to protrude from the mesh of the strip-shaped adhesive. This makes it less likely for the one-side absorbent layer 21 (absorbent core) to collapse during use of the diaper 1.

[0123] Furthermore, the thickness of the one absorbent layer 21 (absorbent core) is preferably greater than 1.5 times the average particle size of the SAP particles. As described with reference to FIG. 6 , in this embodiment, the one absorbent layer 21 is formed by supplying SAP particles in a scattered manner onto a base sheet (core wrap sheet 25) coated with an adhesive. At this time, some of the SAP particles are stacked so as to overlap in the thickness direction, forming the one absorbent layer 21 (absorbent core) that is at least 1.5 times the average particle size of the SAP particles. For example, when the average particle size of the SAP particles is 0.3 to 0.4 mm, the one absorbent layer 21 has a thickness of approximately 0.475 to 0.63 mm. By stacking at least 1.5 layers of SAP particles in the one absorbent layer 21 (absorbent core), water absorption and water retention can be further improved compared to a single-layer absorbent core in which the SAP particles are arranged in a planar manner.

[0124] In this embodiment, the adhesive is present at the center in the thickness direction of the one-side absorbent layer 21 (absorbent core) having 1.5 or more layers. In this embodiment, the width of the strip-shaped (fibrous) adhesive is significantly smaller than the average particle size of the SAP particles (see FIG. 10 ), and a portion of the adhesive is discharged directly toward the SAP particles by the second adhesive dispensing mechanism 150 and the third adhesive dispensing mechanism 160 (see FIG. 6 ). Therefore, the adhesive discharged onto the SAP particles moves through the gaps between the SAP particles from the upper side (skin side) to the lower side (non-skin side) in the thickness direction due to gravity and the pressure during dispensing, and easily reaches the center in the thickness direction of the one-side absorbent layer 21 (absorbent core). In other words, the adhesive easily penetrates into the one-side absorbent layer 21, making it less likely for the SAP particles to become misaligned, and making it less likely for the one-side absorbent layer 21 to collapse. Furthermore, when the base sheet (core wrap sheet 25) is sucked to one side in the thickness direction by the suction mechanism, the adhesive ejected onto the SAP particles is also sucked to one side in the thickness direction (the non-skin side), making it easier to reach the central position in the thickness direction of the one-side absorbent layer 21 (absorbent core).

[0125] Furthermore, the residual stress of the adhesive applied to secure the SAP particles to the skin side of the core wrap sheet 25 is preferably 2 KPa or more and 20 KPa or less. The adhesive that secures the SAP particles is required to have a resistance (residual stress) that prevents the SAP particles from falling off from the core wrap sheet 25 (base sheet) even when external forces associated with the swelling of the SAP particles are applied. If the residual stress of the adhesive is 2 KPa or more and 20 KPa or less, the probability that the SAP fixation rate will be 40% or more increases, making it possible to make the one-side absorbent layer 21 less likely to collapse.

[0126] Here, the SAP fixation rate indicates the proportion of SAP that does not fall off when the absorbent sheet to be measured is immersed in physiological saline (0.9% by mass saline) being stirred at a specified rotation speed, and can be an indicator of the fixation of the absorbed and swollen SAP to the base sheet, with a larger value for the SAP fixation rate indicating a higher fixation of the SAP to the base sheet in the absorbent sheet and less likely to cause SAP to fall off, not only before use but also after absorbing liquid. The SAP fixation rate is measured according to the following procedures 1 to 5.

[0127] (Procedure 1) Prepare a measurement sample from an absorbent sheet that is 5 cm square in plan view. Hold the edge of the measurement sample and temporarily hang it vertically, then measure the weight of the measurement sample (initial sample weight). (Procedure 2) Immerse the entire measurement sample in physiological saline, and remove it from the physiological saline 30 minutes after immersion begins. (Procedure 3) Place a cylindrical stirring bar with a diameter of 35 mm and an axial length of 12 mm and 300 ml of physiological saline in a 300 ml beaker, and use a magnetic stirrer to rotate the stirring bar at a rotation speed of 60 ± 5 rpm to stir the physiological saline. The measurement sample that underwent procedure 2 above is added to the stirred physiological saline, and 30 seconds after addition, remove the measurement sample from the physiological saline. (Step 4) The wet measurement sample that has undergone Step 3 is left to stand for 12 hours in a thermostatic bath whose temperature is set to 105°C, and then the weight of the dry measurement sample (sample weight after stirring treatment) is measured. (Step 5) The total weight of the components other than the water-absorbent polymer is subtracted from each of the initial sample weight and the sample weight after stirring treatment to calculate the initial water-absorbent polymer weight (W0) and the water-absorbent polymer weight after stirring treatment (W1), respectively. Then, the water-absorbent polymer fixation rate of the measurement sample (absorbent sheet) is calculated using the following formula: Water-absorbent polymer fixation rate (%) = (W1 / W0) x 100

[0128] In step 1, the reason for grasping the end of the measurement sample (an absorbent sheet having a square shape in a plan view, 5 cm square) and temporarily suspending it vertically is to remove any unfixed matter, such as a water-absorbent polymer that is not fixed on the base sheet (for example, a water-absorbent polymer that is not fixed with an adhesive or the like but is simply sprinkled from above the base sheet). In suspending the measurement sample, the end of the measurement sample is simply grasped and suspended approximately vertically for approximately 3 to 5 seconds, without striking or violently shaking the suspended measurement sample. Furthermore, when suspending the measurement sample, first, the end of the measurement sample is grasped using tweezers or the like and suspended for 3 to 5 seconds, and then the end opposite to the end grasped during suspension is grasped and suspended for 3 to 5 seconds. Furthermore, in the above-mentioned procedure 1, if it is not possible to prepare an absorbent sheet of 5 cm square as the measurement sample (for example, if the size of the measurement sample is less than 5 cm square due to the small size of the absorbent sheet), multiple small measurement samples of less than 5 cm square are collected from the sheet to be evaluated, and the total area of ​​one side of these multiple measurement samples is 25 cm2. Then, for each of the multiple measurement samples, the water-absorbent polymer fixation rate is measured according to the above-mentioned procedures 1 to 5, and the average value of the multiple water-absorbent polymer fixation rates thus obtained is defined as the water-absorbent polymer fixation rate of the absorbent sheet.

[0129] Examples of measuring equipment used in step 3 include the following: Magnetic stirrer: HI-304N (reverse stirrer, manufactured by HANNA Co., Ltd.) Stirrer: Star head NALGENE (6600-0035) [35φ×12 mm] Beaker: 300 ml [78φ×103 mm]

[0130] The residual stress of an adhesive is measured by the following method. <Method for Measuring Residual Stress of an Adhesive> Using a rotational rheometer (manufactured by Anton Paar, model "Physica MCR301"), the adhesive to be measured is placed between a receiving plate that is circular in plan view and supports the measurement sample from below, and a pressing plate that is also circular in plan view and is placed above the receiving plate to face the receiving plate. In this state, the adhesive has a circular shape in plan view, a thickness of 1.5 mm, a diameter of 12 mm, and a temperature of 30°C. Then, from this state, the pressing plate is rotated to apply a 30% strain to the adhesive. 20 minutes after applying the strain to the adhesive, the shear stress of the adhesive is measured, and this measured value is taken as the residual stress of the adhesive.

[0131] In measuring the residual stress, if the adhesive to be measured is unused (i.e., if it is not applied to a substrate sheet and is not a component of an absorbent sheet), the unused adhesive is used as is for measurement. On the other hand, if the adhesive to be measured is a component of an absorbent sheet, the adhesive is extracted from the absorbent sheet by the solvent extraction method described below, and the extracted adhesive is used for measurement.

[0132] <Solvent extraction method for adhesive> First, an absorbent sheet containing an adhesive is mixed with a solvent capable of dissolving the adhesive in a container such as a beaker to obtain an adhesive solution in which the adhesive is dissolved in the solvent. Next, the adhesive solution is collected from the container, and the adhesive solution is dried under reduced pressure using a rotary evaporator, for example, to remove the solvent from the adhesive solution to obtain an adhesive. The adhesive thus obtained is used as the measurement target for the measurement of the residual stress. The solvent used to dissolve the adhesive may be selected appropriately depending on the type of adhesive, etc. When the adhesive to be measured is, for example, a hot melt adhesive, examples of solvents used to dissolve the adhesive include toluene, methyl ethyl ketone, and heptane.

[0133] Furthermore, after adhesive is discharged from the second adhesive discharging mechanism 150 or the third adhesive discharging mechanism 160 toward the SAP particles (one-side absorbent layer 21), when the intermediate sheet 26 is placed above the SAP particles (see FIG. 6 ), part of the adhesive coated on the surface of the SAP particles adheres to the intermediate sheet 26. That is, part of the strip-shaped adhesive discharged by the second adhesive discharging mechanism 150 or the like is provided on the non-skin-facing surface of the intermediate sheet 26.

[0134] In this embodiment, the adhesive is applied so that the average width of the strip of adhesive on the non-skin-side surface of the intermediate sheet 26 (the surface facing the one-side absorbent layer 21) is greater than the average width of the strip of adhesive on the skin-side surface of the core wrap sheet 25 (the surface facing the one-side absorbent layer 21). This configuration makes it difficult for the adhesive to be applied excessively to the skin-side surface of the core wrap sheet 25, which makes it easier to prevent the adhesive from seeping out to the non-skin-side surface of the core wrap sheet 25. On the other hand, if a larger amount of adhesive is applied to the non-skin-side surface of the intermediate sheet 26, a larger amount of adhesive is ejected toward the SAP particles, which more firmly bonds the SAP particles together and prevents the one-side absorbent layer 21 from losing its shape.

[0135] Conversely, the average width of the strip-shaped adhesive provided on the non-skin-side surface of the intermediate sheet 26 (the surface facing the one-side absorbent layer 21) may be smaller than the average width of the strip-shaped adhesive provided on the skin-side surface of the core wrap sheet 25 (the surface facing the one-side absorbent layer 21). In this case, the amount of adhesive provided on the intermediate sheet 26 is reduced, making it less likely that excreted liquid will be hindered from moving in the thickness direction of the intermediate sheet 26. In other words, it is possible to make it easier for excreted liquid to move smoothly to the one-side absorbent layer 21 provided on the non-skin-side surface of the intermediate sheet 26 in the thickness direction.

[0136] The one-side absorbent layer 21 of the absorber 20 is provided with a low-basis-weight region 211 having a basis weight lower than that of the surrounding area. Excrement is absorbed less easily in the low-basis-weight region 211 than in other regions, and the excrement is more likely to diffuse along the low-basis-weight region 211. For example, the diffusion of excrement in the thickness direction is promoted, which makes it easier for the excrement to move into the one-side absorbent layer 21. Therefore, even if a force that compresses the absorber 20 in the thickness direction is applied, for example, when the wearer assumes a sitting position while wearing the diaper 1, the excrement can be easily drawn into the absorber 20.

[0137] The average basis weight in the low basis weight region 211 of the one absorbent layer 21 is preferably greater than 0% and not greater than 50% of the average basis weight in other regions (regions other than the low basis weight region 211) of the one absorbent layer 21. If the average basis weight in the low basis weight region 211 is not greater than 50% of the average basis weight in other regions, the difference in basis weight between the low basis weight region 211 and other regions becomes greater than when the average basis weight is greater than 50%, which makes it easier to move liquids such as excrement along the low basis weight region 211. Furthermore, if the average basis weight in the low basis weight region 211 is greater than 0%, the low basis weight region 211 is prevented from being entirely configured as a slit, which makes it easier to ensure the strength of the low basis weight region 211. In other words, by providing SAP particles with a certain degree of basis weight, it is possible to improve the liquid diffusibility while preventing the one absorbent layer 21 from losing its shape.

[0138] Furthermore, the width W211 of the low basis weight region 211 is greater than the minimum distance di between the intersections of the strip-shaped adhesive (see FIG. 10 ). If the distance di between the intersections of the strip-shaped adhesive were greater than the width W211 of the low basis weight region 211, there would be a possibility that no intersections of the adhesive between the strip-shaped adhesives would be located between the two side edges of the low basis weight region 211, which would likely cause the SAP to become misaligned in the low basis weight region 211 and prevent the low basis weight region 211 from maintaining its shape. In contrast, in this embodiment, the distance di between the intersections of the strip-shaped adhesives is smaller than the width W211 of the low basis weight region 211, and at least one intersection of the adhesive between the strip-shaped adhesives is located between the two side edges of the low basis weight region 211. This makes it easier for the SAP particles to be fixed in the low basis weight region 211, which has low rigidity. Furthermore, there is a higher possibility that adhesive will be present at the two side edges of the low basis weight region 211. Therefore, the low basis weight region 211 of the one-side absorbent layer 21 is prevented from collapsing or being crushed.

[0139] Furthermore, it is preferable that the low basis weight region 211 has a portion where the core wrap sheet 25 and the intermediate sheet 26 are bonded in the thickness direction. For example, in Fig. 4, if the core wrap sheet 25 and the intermediate sheet 26 are bonded in at least a portion of the portion where the low basis weight region 211 is provided, each of the divided regions 21a, 21b, and 21c of the one-side absorbent layer 21 is firmly divided in the CD direction, and SAP particles are prevented from moving across the low basis weight region 211 between adjacent divided regions. In other words, each of the divided regions 21a, 21b, and 21c easily maintains its shape independently. Therefore, the one-side absorbent layer 21 as a whole is less likely to lose its shape.

[0140] The absorbent body 20 also has intermittent regions at both longitudinal ends where SAP particles are not provided. In FIG. 9 , a front intermittent region FA where SAP particles are not provided is provided in front of the front end 21ef of the one absorbent layer 21 in the longitudinal direction of the core wrap sheet 25 (absorbent body 20). Similarly, a rear intermittent region BA where SAP particles are not provided is provided in back of the rear end 21eb of the one absorbent layer 21 in the longitudinal direction. Because SAP particles are not provided in the front intermittent region FA or the rear intermittent region BA, the core wrap sheet 25 is bonded to a member (e.g., the intermediate sheet 26 in FIG. 4 ) arranged opposite the skin side in the thickness direction via an adhesive applied to the skin side of the core wrap sheet 25. This makes it difficult for the SAP particles constituting the one absorbent layer 21 to protrude to both longitudinal ends, making it less likely for the one absorbent layer 21 to lose its shape.

[0141] Furthermore, it is preferable that the average basis weight of the SAP provided in a region forward of the central position CL in the longitudinal direction of the absorbent body 20 be greater than the average basis weight of the SAP provided behind the central position CL. The front region in the longitudinal direction is located closer to the wearer's excretory opening when the diaper 1 is worn than the rear region. Therefore, by increasing the average basis weight of the SAP in the front region in the longitudinal direction that is closer to the excretory opening, excretions such as urine can be more quickly absorbed, and urine leakage on the abdominal side can be more easily suppressed.

[0142] On the other hand, the average basis weight of the SAPs provided behind the central position CL in the longitudinal direction of the absorbent body 20 may be equal to or greater than the average basis weight of the SAPs provided in the region in front of the central position CL. In this case, the absorbency of the diaper 1 can be increased in the back region of the wearer when the diaper 1 is worn. For example, if the wearer is lying on their back while wearing the diaper 1, excretions such as urine may trickle down the buttocks to the back side and leak out of the absorbent body 20. In such a case, urine leakage from the back side can be more easily suppressed by increasing the average basis weight of the SAPs in the longitudinal rear region as much as possible.

[0143] Furthermore, the absorbent body 20 of this embodiment is provided with an intermediate absorbent layer 22 containing liquid-absorbent fibers 201 and SAP and an other-side absorbent layer 23 (corresponding to a second absorbent layer) that are layered on the other side of the one-side absorbent layer 21 in the thickness direction. That is, the absorbent body 20 is composed of two or more absorbent core layers layered in the thickness direction. The absorbent core having a two-or-more-layer structure improves water absorption and water retention capacity compared to an absorbent core with only one layer. Furthermore, by providing a layer (intermediate absorbent layer 22) containing liquid-absorbent fibers 201 that absorb water faster than SAP particles, liquid diffusion between the multiple layers is facilitated, thereby improving the water absorption and water retention of the absorbent body 20 (absorbent core) as a whole.

[0144] 4, in this embodiment, the one-side absorbent layer 21, which mainly contains SAP particles, is disposed on the non-skin side (one side) in the thickness direction, and the intermediate absorbent layer 22 and the other-side absorbent layer 23 (second absorbent layer), which contain liquid-absorbent fibers 201 that absorb water faster than the SAP particles, are disposed on the skin side (other side) in the thickness direction. Therefore, excreted liquid is quickly drawn from the skin side to the non-skin side and is easily retained in the one-side absorbent layer 21. This improves dryness on the skin side, making it less likely that the wearer will experience discomfort or discomfort.

[0145] 4 , the first absorbent layer 21, which mainly contains SAP particles, may be disposed on the skin side (the other side) in the thickness direction, and the intermediate absorbent layer 22 and the second absorbent layer 23 (second absorbent layer), which contain liquid-absorbent fibers (pulp fibers) 201 that absorb water faster than SAP particles, may be disposed on the non-skin side (the other side) in the thickness direction. In this case, the water retention on the skin side is increased, making it less likely that excreted liquid absorbed by the absorbent core will return to the wearer's skin side, a phenomenon known as rewetting. This reduces the likelihood of discomfort or annoyance to the wearer.

[0146] Furthermore, the core wrap sheet covering the absorbent core (SAP particles) in the absorbent body 20 of the diaper 1 is made of nonwoven fabric. Nonwoven fabrics are generally stronger and more tear-resistant than tissues and the like, making them suitable as base sheets for forming the absorbent body 20. For example, as described with reference to FIG. 6 , when a nonwoven fabric base sheet is conveyed in the MD direction while adhesive is applied or SAP particles are laminated, the tear-resistant base sheet allows the formation of an absorbent body 20 with a stable shape. Furthermore, a suction mechanism or the like allows the base sheet to be conveyed while being sucked, making it easy to fix the SAP particles to the base sheet. In this case, the sucked adhesive moves through the gaps between the SAP particles and easily reaches the inside of the absorbent core (the center position in the thickness direction), making it easier to prevent the SAP particles from misaligning with each other.

[0147] ===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.

[0148] In the above embodiment, the absorbent body 20 is configured with multiple layers as shown in Fig. 4, but the absorbent body 20 is not limited to the configuration shown in Fig. 4. For example, the absorbent body 20 may be configured without the intermediate sheet 26, or may have only one absorbent layer 21 as the absorbent core. Furthermore, the absorbent body 20 may have one side facing the skin in the thickness direction of Fig. 4 and the other side facing away from the skin.

[0149] The absorbent core (one-side absorbent layer 21 and the other-side absorbent layer 23) of the absorbent body 20 may be modified as follows. FIG. 13 is a cross-sectional schematic diagram of the absorbent body 20 showing a modified one-side absorbent layer 21. As shown in FIG. 13, the modified one-side absorbent layer 21 has a high basis weight region 213 in which the basis weight of SAP is higher than that of the surrounding area. In the high basis weight region 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, between adjacent points S of maximum thickness (i.e., around the high basis weight region 213), low basis weight regions 214 in which the basis weight of SAP is lower than that of the high basis weight region 213 are formed. However, as long as the points S of maximum thickness are located intermittently in the longitudinal and width directions, a portion of the area between adjacent points S of maximum thickness may be formed by the high basis weight region 213. In other words, the adjacent maximum thickness points S may be partially connected by the high basis weight region 213 .

[0150] 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.

[0151] 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.

[0152] DESCRIPTION OF SYMBOLS 1 Diaper (absorbent article, pants-type disposable diaper) 2 Side joint portion 10 Absorbent body 12 Top sheet 13a Back sheet (liquid-impermeable sheet) 13b Back sheet (outer sheet) 15 Leakage-barrier wall portion 16 Leakage-barrier wall elastic member 17 Leg-hole elastic member 20 Absorbent body 21 One-side absorbent layer (absorbent core) 211 Low basis weight region 21a Divided region 21b Divided region 21c Divided region 22 Intermediate absorbent layer (absorbent core) 221 Low basis weight region 222 Constricted portion 23 Other-side absorbent layer (absorbent core) 231 Low basis weight region 232 Constricted portion 24 Core wrap sheet 25 Core wrap sheet 26 Intermediate sheet 30 Front waist 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, 100 absorbent body forming device, 110 conveying mechanism, 120 particle supply mechanism, 140 first adhesive discharge mechanism, 140A adhesive discharge row, 140B adhesive discharge row, 141 adhesive discharge section, 141f adhesive discharge region, 141n adhesive non-discharge region, 142 discharge nozzle, 150 second adhesive discharge mechanism, 150A adhesive discharge row, 150B adhesive discharge row, 151 adhesive discharge section, 151f adhesive discharge region, 151n adhesive non-discharge region, 160 third adhesive discharge mechanism, 201 liquid absorbent fiber, SAP superabsorbent polymer, IR inner region, OR outer area

Claims

1. An absorbent article having, in an unfolded state, a longitudinal direction, a width direction, and a thickness direction that are perpendicular to each other, and an absorbent layer containing a superabsorbent polymer, and a core wrap sheet disposed on one side in the thickness direction of the absorbent layer, wherein a strip-shaped adhesive is provided on the other side surface of the core wrap sheet in the thickness direction, the average width of the strip-shaped adhesive is smaller than the average particle diameter of the superabsorbent polymer, a region located outside the outermost end of the absorbent layer in the width direction is defined as an outer region on the other side surface of the core wrap sheet, and a region located inside the outermost end of the absorbent layer in the width direction is defined as an inner region on the other side surface of the core wrap sheet, the number of intersections of the strip-shaped adhesives per unit area in the outer region is less than the number of intersections of the strip-shaped adhesives per unit area in the inner region. An absorbent article characterized by this.

2. The absorbent article according to claim 1, wherein the minimum value of the distance between intersections of the strip-shaped adhesives is smaller than the average particle diameter of the superabsorbent polymer when swollen. An absorbent article characterized by this.

3. The absorbent article according to claim 2, wherein the minimum value of the distance between intersections of the strip-shaped adhesives is smaller than the average particle diameter of the superabsorbent polymer when not swollen. An absorbent article characterized by this.

4. The absorbent article according to any one of claims 1 to 3, wherein the thickness of the absorbent layer is greater than 1.5 times the average particle diameter of the superabsorbent polymer. An absorbent article characterized by this.

5. The absorbent article according to claim 4, wherein at least a part of the strip-shaped adhesive is present at the central position in the thickness direction of the absorbent layer. An absorbent article characterized by this.

6. The absorbent article according to any one of claims 1 to 3, wherein the residual stress of the adhesive for fixing the superabsorbent polymer to the core wrap sheet is 2 kPa or more and 20 kPa or less. An absorbent article characterized by this.

7. The absorbent article according to any one of claims 1 to 3, having an intermediate sheet on the other side in the thickness direction of the absorbent layer, wherein a strip-shaped adhesive is provided on one side surface of the intermediate sheet in the thickness direction, and an average width of the strip-shaped adhesive provided on the other side surface of the core wrap sheet is smaller than an average width of the strip-shaped adhesive provided on one side surface of the intermediate sheet.

8. The absorbent article according to any one of claims 1 to 3, having an intermediate sheet on the other side in the thickness direction of the absorbent layer, wherein a strip-shaped adhesive is provided on one side surface of the intermediate sheet in the thickness direction, and an average width of the strip-shaped adhesive provided on the other side surface of the core wrap sheet is larger than an average width of the strip-shaped adhesive provided on one side surface of the intermediate sheet.

9. The absorbent article according to any one of claims 1 to 3, wherein the absorbent layer has a region having a predetermined width in the width direction and having a low basis weight region where the basis weight is lower than that of the surroundings.

10. The absorbent article according to claim 9, wherein an average basis weight of the low basis weight region is larger than 0% and 50% or less of an average basis weight of a region other than the low basis weight region in the absorbent layer.

11. The absorbent article according to claim 10, wherein a minimum value of a distance between intersections of the strip-shaped adhesives is smaller than a width of the low basis weight region.

12. The absorbent article according to claim 11, having an intermediate sheet on the other side in the thickness direction of the absorbent layer, and having a portion where the core wrap sheet and the intermediate sheet are joined in the thickness direction in the low basis weight region.

13. The absorbent article according to any one of claims 1 to 3, having an absorber including the absorbent layer and the core wrap sheet, and having intermittent regions where the superabsorbent polymer is not provided at front and rear end portions in the longitudinal direction of the absorber.

14. The absorbent article according to claim 13, wherein an average basis weight of the superabsorbent polymer on the front side of the central position in the longitudinal direction of the absorber is smaller than an average basis weight of the superabsorbent polymer on the rear side of the central position in the longitudinal direction of the absorber.

15. The absorbent article according to claim 13, wherein an average basis weight of the superabsorbent polymer on the front side of the central position in the longitudinal direction of the absorber is equal to or greater than an average basis weight of the superabsorbent polymer on the rear side of the central position in the longitudinal direction of the absorber.

16. The absorbent article according to any one of claims 1 to 3, wherein a second absorbent layer containing the superabsorbent polymer and liquid-absorbent fibers is laminated with the absorbent layer in the thickness direction.

17. The absorbent article according to claim 16, wherein the second absorbent layer is disposed on the other side of the absorbent layer.

18. The absorbent article according to claim 16, wherein the second absorbent layer is disposed on the one side of the absorbent layer.

19. The absorbent article according to any one of claims 1 to 3, wherein the core wrap sheet is made of a nonwoven fabric.

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