Absorbent article

Abstract

To make it easy to move excretion from a skin side to a non-skin side in a thickness direction in an absorbent article.SOLUTION: An absorbent article (1) has a longitudinal direction, a width direction, and a thickness direction orthogonal to each other and includes an absorbent core (11), and a core wrap sheet (12) provided further in a skin side than the absorbent core (11). The absorbent core (12) has pulverized fiber. The core wrap sheet (12) has cellulose fiber. An average fiber length of the pulverized fiber is shorter than an average fiber length of the cellulose fiber.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to absorbent articles.

Background Art

[0002] Absorbent articles that absorb excreta such as menstrual blood and urine are known. Absorbent articles are provided with an absorbent member. For example, Patent Document 1 discloses an absorbent member using fluff pulp such as pulp derived from coniferous trees and pulp derived from broad-leaved trees. It is known that the longer the length of the fiber used in this absorbent member, the easier it is to diffuse the excreta absorbed along the fiber. For example, it is known that the fiber length of pulp fibers derived from coniferous trees is relatively long, and the fiber length of pulp fibers derived from broad-leaved trees is relatively short.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an absorbent article is worn, it is preferable to transfer the excreta absorbed from the skin side of the absorbent article to the non-skin side to quickly move the excreta away from the skin of the wearer. In conventional absorbent articles, the excreta absorbed by the absorbent article tend to spread planar rather than transfer from the skin side to the non-skin side, resulting in problems such as excreta remaining on the skin side surface of the absorbent article, causing discomfort to the wearer, or excreta leaking from the absorbent article.

[0005] The present invention has been made in view of the above conventional problems, and its object is to facilitate the transfer of excreta from the skin side to the non-skin side in the thickness direction in an absorbent article.

Means for Solving the Problems

[0006] The main invention for achieving the above object is an absorbent article having a longitudinal direction, a width direction, and a thickness direction that are orthogonal to each other, and including an absorbent core and a core wrap sheet provided on the skin side of the absorbent core, wherein the absorbent core has crushed fibers, the core wrap sheet has cellulose fibers, and the average fiber length of the crushed fibers is shorter than the average fiber length of the cellulose fibers. Other features of the present invention will be clarified by the description in this specification and the accompanying drawings.

Effects of the Invention

[0007] According to the present invention, it becomes easier to transfer excrement from the skin side to the non-skin side in the thickness direction of the absorbent article.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 9

Figure 10

Figure 11

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Figure 13

DETAILED DESCRIPTION OF THE INVENTION

[0009] From the description in this specification and the accompanying drawings, at least the following matters become clear. (Aspect 1) An absorbent article having a longitudinal direction, a width direction, and a thickness direction that are perpendicular to each other, and including an absorbent core and a core wrap sheet provided closer to the skin side than the absorbent core, wherein the absorbent core has crushed fibers, the core wrap sheet has cellulose fibers, and an average fiber length of the crushed fibers is shorter than an average fiber length of the cellulose fibers.

[0010] According to Aspect 1, since the number of contact points where excrement contacts the crushed fibers inside the absorbent core is larger than when the average fiber length of the crushed fibers is longer than the average fiber length of the cellulose fibers, it becomes easier for excrement to migrate from the skin side in the thickness direction to the non-skin side along the fibers in the absorbent core.

[0011] (Aspect 2) The absorbent article according to Aspect 1, having a plurality of absorbent body compression parts obtained by compressing the absorbent core and the core wrap sheet in the thickness direction, wherein a length of the absorbent body compression part in the width direction is thicker than an average fiber width of the crushed fibers, and a part where the absorbent body compression part and the plurality of crushed fibers overlap is provided when viewed in the thickness direction.

[0012] According to Aspect 2, since a plurality of parts where the density of the crushed fibers in the absorbent core is partially increased can be provided, it becomes easier to draw excrement from the core wrap sheet into the absorbent core, and absorption in the absorbent core is facilitated.

[0013] (Aspect 3) It has a central squeezing part obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, and a plurality of the absorber squeezing parts. The central squeezing part is provided along the longitudinal direction and at the central part in the width direction, and a plurality of the absorber squeezing parts are provided on both sides in the width direction of the central squeezing part. The absorbent article according to Embodiment 2 is characterized in that

[0014] According to Embodiment 3, by having the central squeezing part, the absorbent core is deformed so that the central part in the width direction protrudes toward the skin side, promoting diffusion in the longitudinal direction, and the absorber squeezing part facilitates diffusion within the absorbent core. Also, the central squeezing part and the absorber squeezing part make it easier to prevent the shape of the absorbent core from collapsing.

[0015] (Embodiment 4) The absorbent article according to any one of Embodiments 1 to 3, characterized in that no adhesive is provided between the skin side surface of the absorbent core and the non-skin side surface of the core wrap sheet.

[0016] According to Embodiment 4, since the contact part between the absorbent core and the core wrap sheet can be reduced compared to the case where an adhesive is provided between the skin side surface of the absorbent core and the non-skin side surface of the core wrap sheet, it becomes easier to promote absorption in the thickness direction from the state where excrement is diffused in the core wrap sheet to the absorbent core, and thus it becomes easier to improve the absorption speed of excrement.

[0017] (Embodiment 5) The absorbent article according to any one of Embodiments 1 to 4, characterized in that the absorbent core has a superabsorbent polymer, and the cellulose fiber has an average fiber length larger than the average value of the diameters of the superabsorbent polymer in a state not immersed in physiological saline and smaller than the average value of the diameters of the superabsorbent polymer in a state of being immersed in physiological saline for 60 minutes and then drained for 15 minutes.

[0018] According to Embodiment 5, it reduces the possibility that the core wrap sheet hinders the swelling of the superabsorbent polymer, and makes it easier to exhibit the absorption function of the superabsorbent polymer within the absorbent core.

[0019] (Aspect 6) The core wrap sheet has an overlapping portion where the core wrap sheets overlap on the skin side of the absorbent core, and the adhesive is not provided between the core wrap sheets at the overlapping portion. The overlapping portion is provided at the central portion in the width direction and along the longitudinal direction. The length of the overlapping portion in the width direction is longer than the average fiber length of the crushed fibers and is longer than the average fiber length of the cellulose fibers. The absorbent article is any one of Aspects 1 to 5

[0020] According to Aspect 6, since the core wrap sheets are not adhered to the absorbent core and the core wrap sheets are not adhered to each other at the overlapping portion, the penetration of excrement in the thickness direction at the overlapping portion is delayed, and the planar diffusion of excrement in the core wrap sheet, particularly the diffusion in the longitudinal direction, is facilitated. Therefore, it becomes easier to hold the excrement absorbed by the absorbent core in a wide range within the absorbent core

[0021] (Aspect 7) The absorbent article is any one of Aspects 1 to 6, characterized in that the weight ratio of the fibers along the longitudinal direction among the crushed fibers is larger than the weight ratio of the fibers along the longitudinal direction among the cellulose fibers

[0022] According to Aspect 7, by making it easier to diffuse excrement in the longitudinal and width directions in the core wrap sheet and easier to diffuse in the longitudinal direction in the absorbent core, the risk of excrement leaking outside the width direction of the absorbent article can be reduced

[0023] (Aspect 8) The absorbent article is any one of Aspects 1 to 7, characterized in that the average fiber width of the crushed fibers is larger than the average fiber width of the cellulose fibers

[0024] According to Aspect 8, since the absorbent core holds liquid more easily than the koala wrap sheet when the average fiber width of the crushed fibers is made smaller than the average fiber width of the cellulose fibers, the risk of excrement leakage from the absorbent article can be reduced.

[0025] (Aspect 9) The absorbent article according to any one of Aspects 1 to 8, comprising: a plurality of absorbent body squeezing parts obtained by squeezing the absorbent core and the koala wrap sheet in the thickness direction; and a non-squeezing part that, in the thickness direction, is a part where the absorbent core and the koala wrap sheet overlap and where the absorbent body squeezing parts are not provided, wherein the number of fiber masses having a density higher than the average density of the absorbent core and in which the crushed fibers are concentrated in the non-squeezing part of the absorbent core is larger than the number of fiber masses having a density higher than the average density of the koala wrap sheet and in which the cellulose fibers are concentrated in the non-squeezing part of the koala wrap sheet.

[0026] According to Aspect 9, in the koala wrap sheet, it is easier to spread excrement over a wider range than to absorb it, while in the absorbent core, the large number of fiber masses can improve the absorption and liquid retention properties within the absorbent core by capillary action.

[0027] (Aspect 10) The absorbent article according to Aspect 9, wherein the number of fiber masses having a density higher than the average density of the koala wrap sheet and in which the cellulose fibers are concentrated in the non-squeezing part of the koala wrap sheet is zero.

[0028] According to Aspect 10, in the koala wrap sheet, it is easier to spread excrement over a wider range than to absorb it, while in the absorbent core, the large number of fiber masses can improve the absorption and liquid retention properties within the absorbent core by capillary action.

[0029] (Aspect 11) A plurality of absorbent body squeezing parts obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, and a non-squeezing part that is a part where the absorbent core and the core wrap sheet overlap when viewed in the thickness direction and where the absorbent body squeezing parts are not provided. In the non-squeezing part of the absorbent core, there are fiber masses having a density higher than the average density of the absorbent core and in which the crushed fibers are concentrated. The absorbent core has a skin side part, an intermediate part, and a non-skin side part when the absorbent core is divided into three equal parts in the thickness direction. The number of fiber masses in which the crushed fibers are concentrated in the intermediate part is larger than the number of fiber masses in which the crushed fibers are concentrated in the skin side part. The absorbent article is any one of Aspects 1 to 10 having this feature.

[0030] According to Aspect 11, it becomes easier to draw excrement from the skin side part to the intermediate part of the absorbent core, and it becomes easier to prevent the excrement once absorbed in the intermediate part from returning to the skin side part.

[0031] (Aspect 12) A plurality of absorbent body squeezing parts obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, and a non-squeezing part that is a part where the absorbent core and the core wrap sheet overlap when viewed in the thickness direction and where the absorbent body squeezing parts are not provided. In the non-squeezing part of the absorbent core, there are fiber masses having a density higher than the average density of the absorbent core and in which the crushed fibers are concentrated. In the longitudinal direction and the width direction, when the absorbent core is divided into three equal parts, there are a one-side part, a central part, and the other-side part in order from one side. The number of fiber masses in which the crushed fibers are concentrated in the central part is larger than the number of fiber masses in which the crushed fibers are concentrated in the one-side part. The absorbent article is any one of Aspects 1 to 11 having this feature.

[0032] According to Aspect 12, the absorbency in the part close to the wearer's excretory opening can be improved.

[0033] (Aspect 13) The pulverized fibers include hardwood fibers made of hardwood, and in the absorbent article according to any one of Aspects 1 to 12, the weight ratio of the hardwood fibers to the pulverized fibers is 85% or more.

[0034] According to Aspect 13, inside the absorbent core, it becomes easier to form fiber masses in which the pulverized fibers are concentrated, and there are provided portions of the fiber mass with a high fiber density and portions with a lower fiber density than the fiber mass. As a result, while improving the absorbency due to capillary action in the portion of the fiber mass, it becomes easier to hold excrement in the gaps between the fibers in the portion with a lower fiber density than the fiber mass, so that it becomes easier to efficiently absorb excrement with the absorbent core.

[0035] (Aspect 14) The core wrap sheet contains a paper strength enhancer, and the absorbent article according to any one of Aspects 1 to 13 is characterized in that the absorbent core does not contain the paper strength enhancer.

[0036] According to Aspect 14, by providing a paper strength enhancer in the core wrap sheet, while improving the strength of the core wrap sheet, the absorbent core reduces the risk of a decrease in water retention due to the paper strength enhancer, and by covering the absorbent core with a reduced water retention with the core wrap sheet with improved strength, it becomes easier to maintain the shape of the absorbent core.

[0037] ===This Embodiment=== Hereinafter, as an example of the absorbent article according to this embodiment, a sanitary napkin will be described as an example. However, the sanitary absorbent article is not limited to a sanitary napkin, and may be an absorbent pad such as a short-type napkin, a pants-type disposable diaper, a tape-type disposable diaper, etc.

[0038] <<<Configuration of Sanitary Napkin 1 of this Embodiment>>> FIG. 1 is a plan view of the napkin 1 as seen from the skin side. FIG. 2 is a plan view of the napkin 1 as seen from the non-skin side. FIG. 3 is a schematic cross-sectional view taken along the line A-A in FIG. 1. The napkin 1 has a longitudinal direction, a width direction, and a thickness direction. In the longitudinal direction, the side that abuts against the lower abdomen of the wearer is defined as the front side, and the side that abuts against the buttocks of the wearer is defined as the rear side. In the thickness direction, the side that abuts against the skin of the wearer is the skin side, and the opposite side is the non-skin side. The center line C-C shown in FIG. 1 etc. indicates the center of the napkin 1 in the width direction, and the center line CL indicates the center of the napkin 1 in the longitudinal direction. The cross-sectional views such as FIG. 3 schematically show the napkin 1, and the dimensions are not necessarily accurate.

[0039] The napkin 1 has an absorber 10, a topsheet 21, a pair of side sheets 23, and a backsheet 31. A sheet-like second sheet 22 may be provided on the skin side of the absorber 10 and on the non-skin side of the topsheet 21. Each material adjacent to each other in the thickness direction is joined with an adhesive such as hot melt.

[0040] The napkin 1 has a pair of wing portions 1W extending outward on both sides in the width direction at the central portion in the longitudinal direction. The wing portions 1W are mainly formed by the side sheets 23 and the backsheet 31. Note that a configuration not necessarily provided with the wing portions 1W may also be acceptable.

[0041] The topsheet 21 is a liquid-permeable sheet located on the skin side of the absorber 10. The topsheet 21 is a surface sheet that is located on the skin side of the absorber 10 and can abut against the skin of the wearer. Examples of the topsheet 21 include non-woven fabrics made of synthetic fibers such as polyethylene (PE) and polypropylene (PP) (for example, air-through non-woven fabrics and spunbond non-woven fabrics), synthetic resin films having through-holes, and flexible sheets such as non-woven fabric sheets made of cotton. The topsheet 21 of the present embodiment is formed of a liquid-permeable sheet of air-through non-woven fabric or span lace non-woven fabric containing polyethylene terephthalate (PET) and polyethylene (PE), or water-retaining fibers such as cotton and rayon.

[0042] A pair of side sheets 23 are provided on the non-skin side of the top sheet 21 and the second sheet 22 and on the skin side of the absorber 10, and are sheets extending outward from both side portions in the width direction of the top sheet 21 and the like. Examples of the side sheet 23 include the same flexible liquid-permeable non-woven fabric as the top sheet 21, a hydrophobic non-woven fabric, and the like. Further, on the outer side in the width direction of the top sheet 21, the second sheet 22, and the absorber 10, a reinforcing sheet 24 for reinforcing the strength of the side sheet 23 is provided between the side sheet 23 and the back sheet 31 in the thickness direction. As the reinforcing sheet 24, for example, a sheet member similar to the back sheet 31, a sheet member such as paper or SMS can be used.

[0043] The back sheet (non-skin side sheet) 31 is located on the non-skin side of the absorber 10 and is the sheet provided on the outermost non-skin side of the napkin 1. Examples of the back sheet 31 include a liquid-impermeable sheet such as a resin film of polyethylene (PE). The shape of the back sheet 31 is substantially the same as the outer shape of the napkin 1.

[0044] A plurality of main body adhesive portions (adhesive portions) 32 are provided on the non-skin side surface of the back sheet 31. The main body adhesive portion 32 of the present embodiment is an area where a plurality of strip-shaped hot melt adhesives are applied along the longitudinal direction. When the napkin 1 is worn, by attaching the main body adhesive portion 32 to the inside of the crotch portion of the underwear (clothing), the position of the napkin 1 can be prevented from shifting with respect to the wearer's body.

[0045] The wing portion 1W includes a wing adhesive portion 33 on the non-skin side surface of the back sheet 31. The wing adhesive portion 33 of the present embodiment is an area where a rectangular hot melt adhesive is applied. When the napkin 1 is worn, the wing portion 1W can be folded back to the non-skin side surface of the underwear, and the napkin 1 can be fixed to the underwear by attaching the wing adhesive portion 33 to the non-skin side surface in the crotch portion of the underwear.

[0046] The position that overlaps with the wing adhesive part 33 in the longitudinal direction (see FIG. 1) is the crutch region CA. The crutch region CA is a region that abuts against the wearer's crutch in the longitudinal direction in the worn state, and is a region that abuts against the blood discharge port where the wearer's excrement is discharged.

[0047] The absorber 10 has an absorbent core 11 and a core wrap sheet 12. The absorbent core 11 is formed by shaping liquid-absorbent fibers into a predetermined shape, and as the liquid-absorbent fibers, it has crushed fibers. The crushed fibers include hardwood fibers made of hardwood. The absorbent core 11 of the present embodiment contains crushed fibers (pulp fibers), and the crushed fibers are formed only of hardwood fibers (100% hardwood fibers). Note that the absorbent core 11 is not limited to only crushed fibers made of hardwood fibers, and the crushed fibers may include pulp fibers such as softwood fibers made of softwood in addition to hardwood fibers. The absorbent core 11 may include liquid-absorbent fibers such as cellulose-based absorbent fibers, synthetic fibers made of polyolefin, polyester, acrylic, acrylate, etc., or a superabsorbent polymer (SAP). FIG. 4A is a plan view of the absorbent core 11. FIG. 4B is a schematic cross-sectional view taken along the line J-J in FIG. 4A. FIG. 5 is an enlarged schematic cross-sectional view taken along the line K-K in FIG. 4A. FIG. 6 is an enlarged view of the absorber 10 in FIG. 3. In FIGS. 4A, 4B, and 5, the unevenness due to the squeezing part such as the squeezing part EL is shown with omission.

[0048] The absorbent core 11 has a middle and high portion 11d where the basis weight of the liquid-absorbent fibers is higher than that of the surroundings. The middle and high portion 11d is a portion where the thickness of the absorbent core 11 is thicker (the length in the thickness direction is longer) than that of the surroundings. The middle and high portion 11d of the present embodiment is a portion protruding toward the skin side in the thickness direction and is a region having a substantially elliptical shape in plan view. By providing the middle and high portion 11d at the central portion in the width direction of the absorbent core 11 and at a position overlapping the crotch region CA in plan view, it becomes easier to bring it into contact with the wearer's excretion port in the wearing state, makes it easier to fit the napkin 1 to the wearer's body, and makes it easier to quickly absorb excrement. Further, by providing the middle and high portion 11d having a high basis weight of the liquid-absorbent fibers at a position overlapping the crotch region CA in plan view, it becomes easier to hold the excrement discharged from the wearer's excretion port in the absorbent core 11 in the wearing state.

[0049] The core wrap sheet 12 is a liquid-permeable sheet member. The core wrap sheet 12 of the present embodiment is a tissue having cellulose fibers. The core wrap sheet 12 covers the absorbent core 11 to maintain the shape of the absorbent core 11 and to promote the diffusion of liquid to the absorbent core 11.

[0050] As shown in FIG. 6, the core wrap sheet 12 has a skin-side portion 12a located closer to the skin side than the absorbent core 11 and a non-skin-side portion 12b located closer to the non-skin side than the absorbent core 11. In the present embodiment, as shown in FIG. 6 and the like, both side ends of the core wrap sheet 12 are folded back to the skin side of the absorbent core 11, so that the skin-side surface and the non-skin-side surface of the absorbent core 11 are covered with the core wrap sheet 12. Specifically, with the tip 12ea along the longitudinal direction of the core wrap sheet 12 on the outside and the tip 12eb along the other longitudinal direction on the inside, the core wrap sheet 12 wraps the absorbent core 11 so as to cover the side ends in the width direction of the absorbent core 11. However, the shape and form of the core wrap sheet 12 are not limited to this. For example, the core wrap sheet 12 may be configured as two sheet members and disposed on the skin side and the non-skin side of the absorbent core 11, respectively. Note that no adhesive is provided inside the core wrap sheet 12 of the present embodiment. That is, the absorbent core 11 and the core wrap sheet 12 are not fixed with an adhesive, and the shape of the absorbent core 11 is maintained by being wrapped with the core wrap sheet 12.

[0051] FIG. 7 is a plan view of the absorber 10 as viewed from the skin side. In FIG. 7, the raised portion 11d in the absorbent core 11 is shown omitted. As shown in FIG. 7, the absorber 10 has a central squeezing portion 14 and a plurality of absorber squeezing portions 15. The central squeezing portion 14 and the absorber squeezing portions 15 are portions where the absorbent core 11 and the core wrap sheet 12 are squeezed in the thickness direction, respectively.

[0052] The central squeezing portion 14 and the absorber squeezing portions 15 are formed, for example, by squeezing the absorber 10 in the manufacturing process through the roll gap between a convex roller having a plurality of convex portions and an anvil roller with a flat surface. The central squeezing portion 14 and the absorber squeezing portions 15 of the present embodiment are portions where the absorber 10 is pressed from the non-skin side to the skin side by passing the absorber 10 through the roll gap with the convex roller in contact with the non-skin side surface of the absorber 10 and the anvil roller in contact with the skin side surface of the absorber 10.

[0053] The central squeezing portion 14 is a linear squeezing portion provided along the longitudinal direction and at the central portion in the width direction. The central squeezing portion 14 is a portion recessed in the thickness direction from the skin side or the non-skin side from the front end to the rear end of the absorber 10. The central squeezing portion 14 is a guiding portion that guides the absorber 10 to bend toward the skin side in the thickness direction starting from the central squeezing portion 14. Also, since the central squeezing portion 14 has a higher fiber density than the non-squeezed portion, it is also a guiding portion that guides excrement in the longitudinal direction by capillary action.

[0054] The absorber squeezing portions 15 are squeezing portions arranged in a substantially staggered pattern over the entire area of the absorber 10. In the absorber squeezing portions 15 of the present embodiment, a plurality of elliptical squeezing portions are provided. The absorber squeezing portions 15 are also portions recessed in the thickness direction from the skin side or the non-skin side, similar to the central squeezing portion 14. By providing the absorber squeezing portions 15, it becomes easier to maintain the shape of the absorber 10. Also, since the absorber squeezing portions 15 have a higher fiber density than the non-squeezed portions, they become portions that easily absorb excrement in the absorbent core 11 due to capillary action. The difference in density between the absorber squeezing portions 15 and the non-squeezed portions makes it easier to suppress the diffusion of the oil agent Y in the absorbent core 11, which will be described later.

[0055] Also, as shown in FIG. 1 and the like, the napkin 1 has a linear squeezing portion EL and a circular squeezing portion ee. The linear squeezing portion EL is a portion that squeezes at least a part of the topsheet 21, the second sheet 22, and the absorber 10 in the thickness direction. The linear squeezing portion EL of the napkin 1 in the present embodiment has a front squeezing portion ELa provided on the front side of the central line CL in the longitudinal direction, a rear squeezing portion ELb provided on the rear side of the central line CL, and a central squeezing portion ELc provided between the front squeezing portion ELa and the rear squeezing portion ELb. By providing the linear squeezing portion EL, the joining in the thickness direction of each member can be strengthened, the fiber density can be increased, and the liquid absorbency can be improved. The linear squeezing portion EL is a linear squeezing portion along the longitudinal direction in plan view, and a pair of them are provided at a predetermined interval in the width direction. A plurality of circular squeezing portions ee are provided at a central portion in the width direction and at a position overlapping with the calf region CA in the longitudinal direction. The circular squeezing portion ee is a squeezing portion having a circular shape in plan view, and is a portion obtained by squeezing at least a part of the topsheet 21, the second sheet 22, and the absorber 10 in the thickness direction.

[0056] Since the linear squeezing portion EL and the circular squeezing portion ee are portions where the members stacked in the thickness direction are crushed, the fiber density of each member in each squeezing portion is higher than the fiber density of the portion where the squeezing portion is not provided. The linear squeezing portion EL and the circular squeezing portion ee are formed, for example, by squeezing the napkin 1 in the manufacturing process through the roll gap between a convex roller having a plurality of convex portions and an anvil roller having a flat surface.

[0057] <<<Regarding the absorber 10>>> The absorber 10 of the napkin 1 includes an absorbent core 11 and a skin-side portion 12a of a core wrap sheet 12 provided on the skin side of the absorbent core 11. The absorbent core 11 has crushed fibers 11f, and the skin-side portion 12a (core wrap sheet 12) has cellulose fibers 12f. And the average fiber length of the crushed fibers 11f of the absorbent core 11 is shorter than the average fiber length of the cellulose fibers 12f of the skin-side portion 12a.

[0058] The absorbent core 11 has crushed fibers 11f. Examples of the crushed fibers 11f include pulp, such as wood pulp obtained from coniferous trees (e.g., southern yellow pine) or broad-leaved trees (e.g., eucalyptus), bagasse, kenaf, bamboo, hemp, cotton (e.g., cotton linter), etc. non-wood pulp; regenerated cellulose fibers such as rayon fibers; semi-synthetic fibers such as acetate fibers, etc. In absorbent articles, relatively long-fiber coniferous tree fibers (coniferous tree pulp) are often used. In contrast, the crushed fibers 11f of the absorbent core 11 of the present embodiment are composed only of broad-leaved tree fibers (100% broad-leaved tree fibers).

[0059] FIG. 8 is a diagram showing the distribution of fiber lengths of hardwood fibers and softwood fibers. The average fiber length of softwood fibers (softwood pulp) is 2.5 mm, and the average fiber length of hardwood fibers (hardwood pulp) is 0.79 mm. That is, the average fiber length of hardwood fibers is shorter than that of softwood fibers.

[0060] The skin-side portion 12a (koala wrap sheet 12) has cellulose fibers 12f. The cellulose fibers 12f are fibers made from wood or recycled paper, and the main component thereof is cellulose. The koala wrap sheet 12 of the present embodiment is a tissue. Examples of the fibers constituting the tissue include recycled waste paper pulp obtained by recycling wood pulp waste paper derived from softwood or hardwood, non-wood pulp made from plants such as kenaf and bamboo, and synthetic fiber pulp. The tissue of the skin-side portion 12a of the present embodiment is composed of a weight ratio of softwood fibers derived from softwood of 60% to 70% and a weight ratio of hardwood fibers derived from hardwood of 30% to 40%, and contains more softwood fibers having a longer average fiber length. The average fiber length of the cellulose fibers in the skin-side portion 12a is 1.8 mm.

[0061] FIG. 9 is an enlarged schematic diagram for explaining the absorption of excrement by the absorber 10. FIG. 9 is a schematic diagram showing an enlarged part of the skin-side portion 12a and the absorbent core 11. For convenience, the portion where the koala wrap sheets 12 (skin-side portions 12a) are overlapped on the skin side of the absorbent core 11 and the middle-high portion 11d of the absorbent core 11 are omitted.

[0062] The longer the fiber length, the easier it is for excrement (liquid) to diffuse along the fiber. Also, the shorter the fiber length, the shorter the fiber distance is likely to be. Since the average fiber length of the crushed fibers 11f of the absorbent core 11 is shorter than the average fiber length of the cellulose fibers 12f of the skin side portion 12a, it is easier to horizontally diffuse excrement on the skin side portion 12a than when the average fiber length of the crushed fibers 11f is made longer than the average fiber length of the cellulose fibers 12f. When the excrement diffused on the skin side portion 12a reaches the absorbent core 11, the number of contact points where the excrement contacts the crushed fibers 12f inside the absorbent core 11 increases. Therefore, it becomes easier for the excrement to migrate from the skin side to the non-skin side in the thickness direction so as to fall between the crushed fibers 11f along the crushed fibers 11f. Specifically, when worn, when excrement such as menstrual blood is discharged into the crotch region CA, first, it is made easier to diffuse outward from the crotch region CA on the skin side portion 12a provided with cellulose fibers 12f having a long average fiber length. When the diffused excrement migrates from the skin side portion 12a to the absorbent core 11, the excrement moves so as to fall from the skin side to the non-skin side between the crushed fibers 11f having a short average fiber length. Thus, it is possible to reduce the risk that excrement stays on the skin side surface of the crotch region CA and adversely affects the wearer's skin or causes discomfort.

[0063] The fibers of the skin side portion 12a (core wrap sheet) can be taken out, for example, by the following method. First, the napkin 1 is decomposed using toluene to take out the core wrap sheet 12. The taken-out core wrap sheet is dried. Then, the core wrap sheet 15g and about 1.5 L of water (the water is adjusted so as to have a concentration of 1% with respect to the weight of the core wrap sheet) are put into a plastic container (inner diameter: 120 mm, height: 220 mm), and stirred at room temperature for about 24 hours using a stirrer (manufactured by EYELA MAZELA Z, Tokyo Rika Kikai Co., Ltd.). At this time, stir slowly so that the fibers do not break. Thereafter, the fibers dispersed in the water are sucked up together with the water with a dropper (hole diameter: 2 to 3 mm). Collect the extracted fibers by suction filtration and dry them. Regarding the extracted fibers, measure the fiber length using an electron microscope, and calculate the average fiber length from the measured fiber lengths.

[0064] Note that the average fiber length of the crushed fibers of the absorbent core 11 and the average fiber length of the fibers of the skin side portion 12a can be measured by a well-known method. For example, an image is taken using the above-described fiber length distribution measuring device (manufactured by Valmet Corporation, "Valmet FS5"), and the fiber length is obtained by measuring.

[0065] Note that the crushed fibers 11f of the absorbent core 11 may have an average fiber length shorter than that of the cellulose fibers 12f of the skin side portion 12a, and any crushed fibers (such as softwood fibers and hardwood fibers) can be used. Considering that the crushed fibers 11f have an average fiber length shorter than that of the cellulose fibers 12f, it is preferable that the crushed fibers 11f include hardwood fibers.

[0066] As shown in FIG. 7, it is preferable that the napkin 1 (absorbent body 10) has a plurality of absorbent body pressing portions 15 obtained by pressing the absorbent core 11 and the skin side portion 12a (core wrap sheet 12) in the thickness direction. Regarding this absorbent body pressing portion 15, it is preferable that the length W15 in the width direction of the absorbent body pressing portion 15 is thicker than the average fiber width of the crushed fibers 11f, and in the thickness direction, the absorbent body pressing portion 15 and the plurality of crushed fibers 11f have an overlapping portion. When there are some absorbent body pressing portions 15 having different lengths in the width direction, it is sufficient that the length W15 of the portion having the longest length in the width direction is thicker than the average fiber width of the crushed fibers 11f. In the present embodiment, the length W15 in the width direction of the absorbent body pressing portion 15 is 0.5 to 1.0 mm, and since the crushed fibers 11f are hardwood fibers, the average fiber width of the hardwood fibers is about 15 μm. FIG. 10 is a diagram showing the distribution of the average fiber widths of hardwood fibers and softwood fibers.

[0067] The absorber squeezing portion 15 is a portion where the fiber density is increased by squeezing. Therefore, by having a portion where the absorber squeezing portion 15 overlaps with a plurality of crushed fibers 11f, a plurality of portions where the fiber density of the crushed fibers 11f in the absorbent core 11 is partially increased can be provided. As a result, due to capillary action, it becomes easier to draw excrement from the skin side portion 12a toward the absorbent core 11, and it becomes easier to promote the absorption of excrement in the absorbent core 11.

[0068] The average fiber width of the crushed fibers 11f can be measured by a well-known method. For example, it can be measured by the following method. A sample is a cut-out of a site (absorbent core 11) corresponding to the measurement target in a square shape. Using the 3D image connection function of a microscope (VHX-2000 manufactured by KEYENCE, lens VH-Z20W aperture wide open), an enlarged image with a focus from the surface of the sample to a depth of 100 μm (for example, an image magnified 500 times for hardwood fibers and 100 times for softwood fibers) is obtained, and the fiber widths of a plurality of such images are measured to calculate the average fiber width.

[0069] Furthermore, it is preferable that the napkin 1 (absorber 10) has a central squeezing portion 14 in addition to the plurality of absorber squeezing portions 15. The central squeezing portion 14 is provided along the longitudinal direction and at the central portion in the width direction. Regarding these squeezing portions, it is preferable that a plurality of absorber squeezing portions 15 are provided on both sides in the width direction of the central squeezing portion 14. By being such an absorber 10, the central squeezing portion 14 deforms the absorbent core 11 so that the central portion in the width direction of the absorber 10 protrudes toward the skin side, facilitating the diffusion of excrement in the longitudinal direction. Also, the absorber squeezing portion 15 facilitates the diffusion within the absorbent core 11 (absorber 10). Moreover, since the central squeezing portion 14 and the absorber squeezing portion 15 are portions that press the skin side portion 12a and the absorbent core 11 firmly in the thickness direction, by providing these squeezing portions 14, 15, it becomes easier to suppress the collapse of the shape of the absorbent core 11.

[0070] Regarding the skin-side portion (core wrap sheet) 12a of the core wrap sheet 12 that is located closer to the skin side than the absorbent core 11 (Fig. 6), it is preferable that no adhesive is provided between the skin-side surface of the absorbent core 11 and the non-skin-side surface of the skin-side portion 12a. That is, it is preferable that the skin-side surface of the absorbent core 11 and the skin-side portion 12a are not adhered with an adhesive. Thereby, compared with the case where an adhesive is provided between the skin-side surface of the absorbent core 11 and the non-skin-side surface of the skin-side portion 12a, the contact portion between the absorbent core 11 and the skin-side portion 12a can be reduced. Therefore, as shown in Fig. 9, once the excrement is diffused horizontally by the skin-side portion 12a, rather than promoting further horizontal diffusion, it is easier to promote the transfer of excrement from the skin-side portion 12a to the absorbent core 11 in the thickness direction (non-skin side) and the absorption within the absorbent core 11. Therefore, when worn, by promoting the diffusion of the excrement absorbed on the skin-side surface of the napkin 1 and the absorption in the thickness direction of the absorbent core 11, the absorption rate of the excrement as the napkin 1 can be improved, and the possibility that the excrement remains on the skin-side surface of the napkin 1 and has an adverse effect on the skin of the wearer or causes discomfort can be reduced.

[0071] As shown in Fig. 6 and the like, it is preferable that the core wrap sheet 12 (skin-side portion 12a) has an overlapping portion 12r where the core wrap sheets 12 overlap on the skin side of the absorbent core 11. In the present embodiment, in the skin-side portion 12a, as shown in Figs. 6 and 7, while the core wrap sheet 12 covers the non-skin-side surface of the absorbent core 11, both side ends of the core wrap sheet 12 are folded back to the skin side of the absorbent core 11. The tip 12ea along the longitudinal direction folded back from the other side in the width direction toward the skin side is the outer side (skin side), and the tip 12eb along the longitudinal direction folded back from one side in the width direction toward the skin side is the inner side (non-skin side). By arranging such that the tip 12ea is located on one side in the width direction rather than the tip 12eb, the overlapping portion 12r is provided in the skin-side portion 12a.

[0072] In the case where the core wrap sheets 12 of the napkin 1 have an overlapping portion 12r where they overlap each other, it is preferable that no adhesive is provided between the skin side surface of the absorbent core 11 and the non-skin side surface of the skin side portion 12a. As shown in FIG. 7, it is preferable that the overlapping portion 12r is provided at the central portion in the width direction and along the longitudinal direction. And the length W12r in the width direction of the overlapping portion 12r (in this embodiment, the length W12r is 5 mm) is longer than the average fiber length of the pulverized fibers (in this embodiment, 0.79 mm), and it is preferable that the length W12r in the width direction of the overlapping portion W12r is longer than the average fiber length of the cellulose fibers (in this embodiment, 1.8 mm). Since the skin side portion 12a is not adhered to the absorbent core 11 and the core wrap sheets 12 are not adhered to each other at the overlapping portion 12r, it is easy to provide a portion where the core wrap sheets 12 and the skin side portion 12a and the absorbent core 11 are not in close contact. And since the length W12r in the width direction of the overlapping portion 12r is longer than the average fiber length of the pulverized fibers, and the length W12r in the width direction of the overlapping portion W12r is longer than the average fiber length of the cellulose fibers, it is easy to delay the penetration of excrement from the skin side portion 12a to the absorbent core 11 and the penetration of excrement in the thickness direction at the overlapping portion 12r. Therefore, when excrement is absorbed during wearing, planar diffusion in the core wrap sheet 12, particularly, since the overlapping portion 12r is along the longitudinal direction, it is easy to promote the longitudinal diffusion of excrement. Therefore, by once transferring the excrement diffused at the skin side portion 12a to the absorbent core 11 and absorbing it later, it becomes easy to absorb and hold the excrement in a wide range within the absorbent core 11.

[0073] No adhesive is provided between the skin side surface of the absorbent core 11 and the non-skin side surface of the skin side portion 12a. When the absorbent core 11 has a superabsorbent polymer (hereinafter also referred to as "SAP"), the average fiber length of the cellulose fibers 12f of the skin side portion 12a is larger than the average value of the particle diameters of the superabsorbent polymer in a state where it is not immersed in physiological saline. Further, it is preferable that the average fiber length of the cellulose fibers 12f of the skin side portion 12a is smaller than the average value of the particle diameters of the superabsorbent polymer in a state where it is immersed in physiological saline for 60 minutes and then drained for 15 minutes.

[0074] In the state of not being immersed in physiological saline, that is, before absorbing excrement, the average fiber length of the cellulose fiber 12f on the skin side 12a is made larger than the average value of the particle diameter of the superabsorbent polymer. After being immersed in physiological saline, that is, after absorbing excrement, the average fiber length of the cellulose fiber 12f on the skin side 12a is smaller than the average value of the particle diameter of the superabsorbent polymer, so that the risk that the skin side 12a hinders the swelling of the superabsorbent polymer can be reduced, and the water absorption function and water retention function of the superabsorbent polymer can be easily exerted.

[0075] Figure 11 is a table showing the change in the diameter of SAP when it is swollen at a predetermined water absorption ratio and water retention ratio. In Figure 11, the SAP particle size shown at the left end represents the particle size of SAP before swelling, and the SAP diameter shown on the right represents the average particle diameter (average diameter) of SAP after swelling according to the water supply ratio (water retention ratio). Specifically, it shows the result of calculating the average value of the diameter of each SAP when water (physiological saline) is absorbed (dehydrated) at a water absorption ratio (water retention ratio) of 10 to 120 times for SAP with a particle diameter (diameter) of 150 to 850 μm before swelling. Here, the "water absorption ratio" refers to the value obtained by dividing the saturated amount of water that a water absorption medium such as SAP can absorb and retain by the weight of the water absorption medium before water absorption. The "water retention ratio" refers to the value obtained by dividing the amount of water that can be retained after the water absorption medium such as SAP has released (dehydrated) the absorbed water by the weight of the water absorption medium before water absorption.

[0076] The measurement of the water absorption ratio (water retention ratio) of SAP was carried out according to the following procedure with reference to "JIS K 7223-1996 Test Method for Water Absorption of Superabsorbent Resins". First, under the conditions of temperature: 20°C, relative humidity: 60%, pressure (standard atmospheric pressure): 1 atm (101.325 kPa) (for example, in a laboratory maintained at these conditions), prepare the SAP to be measured. Store the SAP in a predetermined container, turn it upside down, and shake it more than 10 times to evenly mix the SAP particles. Weigh out exactly 1.00 g of the mixed SAP using a medicine spoon or the like, and put it into a separately prepared nylon net bag. The nylon net bag can be, for example, a bag formed by overlapping two 200 mm × 200 mm square nylon nets, performing heat sealing at a position 5 mm from the edge of the nylon net for three sides of the square, and leaving only one side of the square open. As the nylon net, for example, a 250-mesh nylon net (N-No. 250HD) manufactured by NBC Industries can be used.

[0077] After putting the SAP into the nylon net bag, heat-seal the opening of the nylon net bag to enclose the SAP so that it does not spill out of the nylon net bag. Then, put 1000 ml of physiological saline into a beaker, and immerse the nylon bag (SAP) in the physiological saline to such an extent that one side of the nylon bag with the SAP touches the bottom of the beaker. And fix one side of the upper part of the nylon bag to the edge of the beaker with a laundry clip or the like so that the SAP and the nylon mesh do not adhere to each other as much as possible. Leave it in this state for 60 minutes.

[0078] The physiological saline to be used is prepared by placing a 3-liter beaker on an electronic balance and zero-resetting it, then adding ion-exchanged water to 27.0 g of sodium chloride (reagent grade 1) to make 3000.0 g, and stirring it with a stirring rod until it can be visually confirmed that the sodium chloride has dissolved.

[0079] After leaving it for 60 minutes, lift the nylon bag filled with SAP from the beaker, pinch the upper center of the nylon bag (for example, at a position 5 mm from the upper end of the nylon bag and 50 mm from both side ends) with laundry scissors, suspend it in the air, leave it for 15 minutes, and drain the water. Then, after 15 minutes, measure the weight of the nylon bag filled with SAP. Repeat this experiment multiple times (for example, 5 times), and take the average value of the measured weights as the water absorption weight B.

[0080] Next, dehydrate the drained nylon bag (SAP) using a centrifuge (HI30) manufactured by Kokusan Co., Ltd. For example, perform dehydration at a rotation speed of 850 rpm (150G) for 90 seconds. Then, measure the weight of the nylon bag (SAP) after dehydration. Repeat this experiment multiple times (for example, 5 times), and take the average value of the measured weights as the water retention weight C.

[0081] The water absorption amount of SAP is obtained by subtracting the weight K of the nylon net obtained in the blank test from the water absorption weight B, and the water absorption ratio of SAP is calculated by dividing the water absorption amount by the sample weight (1.00 g). Similarly, the water retention amount of SAP is obtained by subtracting the weight K' of the nylon net obtained in the blank test from the water retention weight C, and the water retention ratio of SAP is calculated by dividing the water retention amount by the original sample weight (1.00 g).

[0082] Also, measure the diameter (particle size) of SAP before swelling and the diameter (particle size) after swelling using a microscope. Then, based on the relationship between the measurement results of the water absorption ratio (water retention ratio) of SAP and the measured diameter (particle size), create a table (Figure 11) showing the relationship between the water absorption ratio of SAP and the diameter (particle size) before and after swelling.

[0083] As shown in FIG. 11, in the range where the water absorption ratio (water retention ratio) of SAP is 10 to 120 times, the average diameter (average particle size) of SAP after swelling (after water absorption or dehydration) is larger than the diameter of SAP before swelling (150 to 850 μm). For example, in FIG. 11, when the absorption ratio (water retention ratio) is 40 times, the diameter of SAP before swelling is 500 μm (0.5 mm), while the diameter of SAP after swelling (after water absorption) is 2.12 mm. In FIG. 11, when the water absorption ratio and the water retention ratio are the same, the average diameter of SAP after swelling is also the same value. This is because the diameter of SAP after swelling is defined by the amount of water (physiological saline in this embodiment) held in the SAP. That is, if the amount of water held by SAP after dehydration is equal to the amount of water held by SAP after water absorption, the average diameter of SAP will also be equal.

[0084] As described above, the average fiber length of the cellulose fibers in the skin side portion 12a is 1.8 mm. As shown in FIG. 11, it can be seen that the particle size (particle diameter) of the superabsorbent polymer after swelling may be larger than the average fiber length (1.8 mm) of the cellulose fibers in the skin side portion 12a.

[0085] FIG. 12 is a table showing the particle size distribution of SAP used in this embodiment. As shown in FIG. 12, for the SAP used in this embodiment, those with a particle size before swelling in the range of 250 to 600 μm account for 79% (average value) of the whole, those in the range of 600 μm to 850 μm account for 12% (average value) of the whole, and those with a particle size of 850 μm or more are 0 percent (average value). Also, those in the range of 0 μm to 250 μm account for 10% (average value) of the whole. Therefore, according to the data in FIG. 11, it can be seen that about 32% of the SAP contained in the absorber 10 of this embodiment has an average particle size (particle diameter) of the superabsorbent polymer after swelling larger than the average fiber length (1.8 mm) of the cellulose fibers.

[0086] By making the average particle diameter of the superabsorbent polymer after swelling larger than the average fiber length of the cellulose fibers in the skin-side portion 12a, the water absorption performance of the SAP can be improved. That is, the average value of the fiber length of the cellulose fibers in the skin-side portion 12a is smaller than the average value of the diameter of the SAP (superabsorbent polymer) in a state where it has been immersed in physiological saline for 60 minutes and then drained for 15 minutes, whereby the water absorption of the absorber 10 can be improved.

[0087] Also, it is preferable that the average fiber width of the crushed fibers 11f of the absorbent core 11 is larger than the average fiber width of the cellulose fibers 12f of the skin-side portion 12a. In the present embodiment, the average fiber width of the crushed fibers 11f of the absorbent core 11 is about 15 μm, and the average fiber width of the cellulose fibers 12f of the skin-side portion 12a is 24 μm. The larger the average fiber width, the higher the retention of excrement (liquid). Therefore, since the average fiber width of the crushed fibers 11f of the absorbent core 11 is larger than the average fiber width of the cellulose fibers 12f of the skin-side portion 12a, the liquid retention in the absorbent core 11 is more likely to be higher than the liquid retention in the skin-side portion 12a than when the average fiber width of the crushed fibers 11f is made smaller than the average fiber width of the cellulose fibers 12f. As a result, it becomes easier for the absorbent core 11 to absorb the excrement absorbed from the skin-side portion 12a, reduces the risk of excrement remaining in the skin-side portion 12a, and makes it easier for the absorbent core 11 to hold the excrement, thereby reducing the risk of excrement leaking from the napkin 1.

[0088] Also, it is preferable that the weight ratio of the fibers along the longitudinal direction among the crushed fibers 11f of the absorbent core 11 is larger than the weight ratio of the fibers along the longitudinal direction among the cellulose fibers 12f of the skin-side portion 12a. That is, the cellulose fibers 12f have a larger weight ratio of the fibers along the width direction than the crushed fibers 11f. The cellulose fibers 12f of the skin-side portion 12a of the present embodiment are provided randomly along the longitudinal direction and the width direction respectively, and among the crushed fibers 11f of the absorbent core 11, the weight ratio of the fibers along the longitudinal direction is larger than the weight ratio of the fibers along the width direction. Excrement is likely to diffuse along the fibers. Therefore, in the skin-side portion 12a, it is easy to diffuse excrement in the longitudinal direction and the width direction by the cellulose fibers 12f, and in the absorbent core 11, it is easy to diffuse excrement in the longitudinal direction by the crushed fibers 11f. As a result, the risk of excrement leaking to the outside in the width direction of the entire napkin 1 can be reduced.

[0089] It is preferable that the skin-side portion 12a (core wrap sheet 12) contains a paper strength enhancer while the absorbent core 11 does not contain a paper strength enhancer. A paper strength enhancer is a chemical for binding pulp fibers together to make the paper difficult to break against liquids, strengthen it, improve the touch feeling, and make it soft and elastic. Examples of the paper strength enhancer include polyamideamine epichlorohydrin (PAE). By providing this paper strength enhancer in the skin-side portion 12a (core wrap sheet 12), the strength of the skin-side portion 12a can be improved. On the other hand, by not providing a paper strength enhancer in the absorbent core 11, the risk of the water retention of the absorbent core 11 decreasing can be reduced. That is, by covering the absorbent core 11 with a reduced water retention due to not having a paper strength enhancer with the skin-side portion 12a with improved strength due to having a paper strength enhancer, the shape of the absorbent core 11 can be easily maintained.

[0090] In the absorbent core 11, it is preferable that the shredded fibers 11f contain hardwood fibers made of hardwood. And it is preferable that the weight ratio of the hardwood fibers to the shredded fibers in the absorbent core 11 is 85% or more. In conventional absorbent articles such as napkins 1, etc., it is common to have softwood fibers with a relatively long average fiber length as the shredded fibers. In contrast, in the absorbent core 11 of the napkin 1 of this embodiment, hardwood fibers are used as the shredded fibers 11f, and the shredded fibers 11f of the absorbent core 11 are composed of 100% hardwood fibers. The greater the weight ratio of the hardwood fibers with a relatively short average fiber length in the shredded fibers 11f within the absorbent core 11, the easier it is to form fiber masses fk in which the shredded fibers are densely packed inside the absorbent core 11. The absorbent core 11 provided with the fiber masses fk is provided with a portion of the fiber mass fk having a high fiber density and a portion having a lower fiber density than the fiber mass fk. In this way, by having portions with different fiber densities, the absorbency due to capillary action in the portion of the fiber mass fk is improved, and it becomes easier to hold excrement in the gaps between the fibers in the portion having a lower fiber density than the fiber mass fk. Therefore, it becomes easier to efficiently absorb excrement within the absorbent core 11.

[0091] Also, as described above, the napkin 1 has an absorbent body squeezing portion 15 in which the absorbent core 11 and the skin side portion 12a (core wrap sheet 12) are squeezed in the thickness direction. When, in the thickness direction, the portion where the absorbent core 11 and the skin side portion 12a overlap and the absorbent body squeezing portion 15 is not provided is defined as the non-squeezing portion, it is preferable that the number of fiber masses fk in the non-squeezing portion of the absorbent core 11 is larger than the number of fiber masses in the non-squeezing portion of the skin side portion 12a (core wrap sheet). Furthermore, it is preferable that the number of fiber masses in the non-squeezing portion of the skin side portion 12a (core wrap sheet 12) is 0 (zero). The fiber mass fk of the absorbent core 11 is a portion in the absorbent core 11 where the density is higher than the average density of the absorbent core 11 and the shredded fibers are densely packed. The fiber mass of the skin side portion 12a (core wrap sheet 12) is a portion in the skin side portion 12a where the density is higher than the average density of the skin side portion 12a and the cellulose fibers 12f are densely packed.

[0092] The number of fiber masses fk in the absorbent core 11 is larger than the number of fiber masses in the skin side portion 12a. Thus, in the skin side portion 12a, it is easier to spread excrement in a wide horizontal range than to absorb excrement or penetrate it in the non-skin side direction in the thickness direction. Also, in the absorbent core 11 with a large number of fiber masses fk, it becomes easier to improve the absorption of excrement and the retention of liquid (excrement) in the absorbent core 11 due to capillary action in the fiber masses fk.

[0093] Regarding the non-squeezed portion, when the absorber 10 and the napkin 1 include squeezing portions such as a central squeezing portion 14, a linear squeezing portion EL, and a dot squeezing portion ee in addition to the absorber squeezing portion 15, the non-squeezed portion is a portion where none of these squeezing portions are provided.

[0094] The fiber mass fk is a portion where pulp fibers remain in a ball shape without being pulverized during the manufacturing process. The fiber mass fk is a high-density portion where pulp fibers are densely packed in a ball shape. When fiber masses are provided, since the fiber mass fk is a high-density portion of fibers and the periphery of the fiber mass fk is a low-density portion with a lower fiber density than the fiber mass fk, a difference in fiber density occurs, and absorption proceeds easily due to capillary action. Also, by having the fiber mass fk, the absorbent core 11 and the core wrap sheet 12 have a high-density portion and a low-density portion in the thickness direction. For example, compared with the case where the high-density portions are continuous in the thickness direction such as in the squeezing portions 14, 15, etc., it is easier to maintain the thickness (bulk) of the member, and it is easy to make it soft and enhance the cushioning property.

[0095] Also, when the absorbent core 11 has fiber masses fk in the non-compressed part, in the non-compressed part of the absorbent core 11, as shown in FIG. 5, when the absorbent core 11 is divided into three equal parts in the thickness direction, from the skin side toward the non-skin side, it has an upper part (skin side part) 11a, an intermediate part 11b, and a lower part (non-skin side part) 11c in order. In such a case, it is preferable that the number of fiber masses fk in the intermediate part 11b is larger than the number of fiber masses fk in the upper part 11a. Since the fiber masses fk in the absorbent core 11 are parts with a high fiber density, when the number of fiber masses fk in the intermediate part 11b is larger than the number of fiber masses fk in the upper part 11a, it becomes easier to draw excrement from the upper part 11a to the intermediate part 11b of the absorbent core 11, that is, from the skin side to the non-skin side in the thickness direction, and it also becomes easier to prevent the excrement once absorbed in the intermediate part 11b from returning to the upper part 11a.

[0096] FIG. 13 is a diagram for explaining each part in the longitudinal direction and the width direction of the absorbent core 11. As shown in FIG. 13, in the longitudinal direction of the napkin 1, when the absorbent core 11 is divided into three equal parts, it has a front part (one side part) Ta, a central part Tb, and a rear part (the other side part) Tc in order from the front side (one side) in the longitudinal direction. Also, in the width direction of the napkin 1, when the absorbent core 11 is divided into three equal parts, it has a left side part (one side part) Wa, a central part Wb, and a right side part (the other side part) Wc in order from one side.

[0097] In such a case, it is preferable that the number of fiber masses fk in which the crushed fibers 11f are concentrated in the central part Tb is larger than the number of fiber masses fk in which the crushed fibers 11f are concentrated in the front part Ta, and the number of fiber masses fk in which the crushed fibers 11f are concentrated in the central part Wb is larger than the number of fiber masses fk in which the crushed fibers 11f are concentrated in the left side part Wa. The central part (the part that is the central part Tb and also the central part Wb) in the longitudinal direction and the width direction of the absorbent core 11 is a part that is likely to come into contact with the excretory opening such as the vaginal orifice of the wearer during wearing. Therefore, by increasing the number of fiber masses fk in the central part Tb and the central part Wb, the absorbency in the part close to the excretory opening of the wearer can be improved.

[0098] ===Other Embodiments=== As described above, the embodiments of the present invention have been explained. However, the above embodiments are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. Further, the present invention can be changed and improved without departing from its gist, and it goes without saying that equivalents of the present invention are included therein.

Description of Reference Numerals

[0099] 1 Napkin (Absorbent Article), 1W Wing Portion, 10 Absorbent Body, 11 Absorbent Core, 11d Medium-High Portion, 12 Core Wrap Sheet, 12a Skin Side Portion (Core Wrap Sheet), 12b Non-Skin Side Portion, 14 Central Squeezing Portion, 15 Absorbent Body Squeezing Portion, 21 Top Sheet (Surface Sheet), 22 Second Sheet, 23 Side Sheet, 24 Reinforcing Sheet, 31 Back Sheet (Non-Skin Side Sheet), 32 Main Body Adhesive Portion (Adhesive Portion), 33 Wing Adhesive Portion, CA Instep Region, ee Circular Squeezing Portion, EL Linear Squeezing Portion

Claims

1. having a longitudinal direction, a width direction, and a thickness direction that are orthogonal to each other, an absorbent core, and a core wrap sheet provided closer to the skin side than the absorbent core, An absorbent article comprising: the absorbent core has crushed fibers, the core wrap sheet has cellulose fibers, the average fiber length of the crushed fibers is shorter than the average fiber length of the cellulose fibers An absorbent article characterized by the above.

2. The absorbent article according to claim 1, having a plurality of absorbent body squeezing portions obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, the length of the absorbent body squeezing portion in the width direction is wider than the average fiber width of the crushed fibers, An absorbent article characterized by having a portion where the absorbent body squeezing portion and the plurality of crushed fibers overlap when viewed in the thickness direction.

3. The absorbent article according to claim 2, having a central squeezing portion and a plurality of absorbent body squeezing portions obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, the central squeezing portion is provided along the longitudinal direction and at the central portion in the width direction, An absorbent article characterized in that a plurality of the absorbent body squeezing portions are provided on both sides in the width direction of the central squeezing portion.

4. The absorbent article according to claim 1 or 2, An absorbent article characterized in that no adhesive is provided between the skin side surface of the absorbent core and the non-skin side surface of the core wrap sheet.

5. The absorbent article according to claim 1 or 2, the absorbent core has a superabsorbent polymer, the cellulose fibers have an average fiber length that is, larger than the average value of the diameters of the superabsorbent polymer in a state not immersed in physiological saline, smaller than the average value of the diameters of the superabsorbent polymer in a state where it has been immersed in physiological saline for 60 minutes and then drained for 15 minutes An absorbent article characterized by having fibers.

6. The absorbent article according to claim 1 or 2, the core wrap sheet has an overlapping portion where the core wrap sheets overlap on the skin side of the absorbent core, no adhesive is provided between the core wrap sheets in the overlapping portion, the overlapping portion is provided at the central portion in the width direction and along the longitudinal direction, the length of the overlapping portion in the width direction is longer than the average fiber length of the crushed fibers, and, The absorbent article is characterized in that the length of the overlapping portion in the width direction is longer than the average fiber length of the cellulose fibers.

7. The absorbent article according to claim 1 or 2, wherein the weight ratio of the fibers along the longitudinal direction among the pulverized fibers is larger than the weight ratio of the fibers along the longitudinal direction among the cellulose fibers.

8. The absorbent article according to claim 1 or 2, wherein the average fiber width of the pulverized fibers is larger than the average fiber width of the cellulose fibers.

9. The absorbent article according to claim 1 or 2, having a plurality of absorber squeezing portions obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, and, when viewed in the thickness direction, having a non-squeezing portion where the absorbent core and the core wrap sheet overlap and no absorber squeezing portion is provided, wherein the number of fiber masses having a density higher than the average density of the absorbent core and in which the pulverized fibers are concentrated in the non-squeezing portion of the absorbent core is more than the number of fiber masses having a density higher than the average density of the core wrap sheet and in which the cellulose fibers are concentrated in the non-squeezing portion of the core wrap sheet.

10. The absorbent article according to claim 9, wherein the number of fiber masses having a density higher than the average density of the core wrap sheet and in which the cellulose fibers are concentrated in the non-squeezing portion of the core wrap sheet is zero.

11. The absorbent article according to claim 1 or 2, having a plurality of absorber squeezing portions obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction, and, when viewed in the thickness direction, having a non-squeezing portion where the absorbent core and the core wrap sheet overlap and no absorber squeezing portion is provided, wherein in the non-squeezing portion of the absorbent core, there is a fiber mass having a density higher than the average density of the absorbent core and in which the pulverized fibers are concentrated, the absorbent core has a skin side portion, an intermediate portion, and a non-skin side portion when the absorbent core is trisected in the thickness direction, and the number of fiber masses in which the pulverized fibers are concentrated in the intermediate portion is larger than the number of fiber masses in which the pulverized fibers are concentrated in the skin side portion.

12. The absorbent article according to claim 1 or 2, A plurality of absorbent body squeezing parts obtained by squeezing the absorbent core and the core wrap sheet in the thickness direction; In the thickness direction view, it has a non-squeezing part where the absorbent core and the core wrap sheet overlap and no absorbent body squeezing part is provided; In the non-squeezing part of the absorbent core, it has fiber masses with a density higher than the average density of the absorbent core and in which the crushed fibers are concentrated; In the longitudinal direction and the width direction, when the absorbent core is divided into three equal parts, it has a one-side part, a central part, and a the other-side part in order from one side; An absorbent article, characterized in that the number of fiber masses in which the crushed fibers are concentrated in the central part is larger than the number of fiber masses in which the crushed fibers are concentrated in the one-side part.

13. The absorbent article according to claim 1 or 2, The crushed fibers include hardwood fibers made of hardwood, An absorbent article, characterized in that the weight ratio of the hardwood fibers to the crushed fibers is 85% or more.

14. The absorbent article according to claim 1 or 2, The core wrap sheet contains a paper strength enhancer, An absorbent article, characterized in that the absorbent core does not contain the paper strength enhancer.

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