Absorbent article

Abstract

The present invention provides an absorbent article (1) having a longitudinal direction, a width direction, and a thickness direction which are orthogonal to each other, the absorbent article (1) comprising: an absorbent core (11); this absorbent article (1) is characterized in that the absorbent core (11) has pulverized fibers, the core wrapping sheet (12) has cellulose fibers, and the average fiber length of the pulverized fibers is shorter than the average fiber length of the cellulose fibers.

Description

Technical Field

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

[0002] Absorbent articles for absorbing excreta such as menstrual blood and urine are known. An absorbent article includes 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. Regarding the fibers used for the absorbent member, it is known that the longer the fiber length, the easier it is for the absorbed excreta to spread along the fibers. 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.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-147290 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When wearing an absorbent article, it is preferable to transfer the excreta absorbed from the skin side of the absorbent article to the non-skin side, so that the excreta is quickly moved away from the skin of the wearer. In conventional absorbent articles, the excreta absorbed by the absorbent article is more likely to spread flatly than to transfer from the skin side to the non-skin side. Therefore, there are problems such as the excreta remaining on the skin side of the absorbent article and causing discomfort to the wearer or the excreta leaking from the absorbent article.

[0008] The present invention has been completed in view of the above-mentioned conventional problems, and an object thereof is to facilitate the transfer of excreta in the absorbent article from the skin side in the thickness direction to the non-skin side.

[0009] Means for Solving the Problems

[0010] The main invention for achieving the above object is an absorbent article having a length direction, a width direction, and a thickness direction orthogonal to each other, including: an absorbent core; and a core wrapper sheet provided on the skin side of the absorbent core. The absorbent article is characterized in that the absorbent core has crushed fibers, the core wrapper sheet has cellulose fibers, and the average fiber length of the crushed fibers is shorter than the average fiber length of the cellulose fibers.

[0011] According to the description of the present specification and the drawings, other features of the present invention become clear.

[0012] Effects of the Invention

[0013] According to the present invention, it is easy to transfer excrement in the absorbent article from the skin side to the non-skin side in the thickness direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a plan view of the sanitary napkin 1 as viewed from the skin side.

[0015] Figure 2 FIG. is a plan view of the sanitary napkin 1 as viewed from the non-skin side.

[0016] Figure 3 FIG. is Figure 1 a schematic cross-sectional view taken along the line A-A in FIG.

[0017] Figure 4A FIG. is a plan view of the absorbent core 11. Figure 4B FIG. is Figure 4A a schematic cross-sectional view taken along the line J-J in FIG.

[0018] Figure 5 FIG. is Figure 4A an enlarged schematic view of a cross-section taken along the line K-K in FIG.

[0019] Figure 6 FIG. is Figure 3 an enlarged view of the absorber 10 in FIG.

[0020] Figure 7 FIG. is a plan view of the absorber 10 as viewed from the skin side.

[0021] Figure 8 FIG. is a graph showing the distribution of fiber lengths of hardwood fibers and softwood fibers.

[0022] Figure 9 FIG. is an enlarged schematic view illustrating the absorption of excrement by the absorber 10.

[0023] Figure 10 FIG. is a graph showing the distribution of average fiber widths of hardwood fibers and softwood fibers.

[0024] Figure 11 FIG. is a table showing the change in the diameter of SAP when SAP is swollen at a predetermined water absorption ratio / water retention ratio.

[0025] Figure 12 FIG. is a table showing the particle size distribution of the SAP used in the present embodiment.

[0026] Figure 13 FIG. is a diagram for explaining each part in the length direction and width direction of the absorbent core 11.

[0027] REFERENCE MARK DESCRIPTION

[0028] 1. Sanitary napkin (absorbent article); 1W. Wing; 10. Absorbent body; 11. Absorbent core; 11d. Middle high part; 12. Core wrapper sheet; 12a. Skin side part (core wrapper sheet); 12b. Non-skin side part; 14. Central compression part; 15. Absorbent body compression part; 21. Topsheet (surface sheet); 22. Second sheet; 23. Side sheet; 24. Reinforcing sheet; 31. Backsheet (non-skin side sheet); 32. Main body adhesive part (adhesive part); 33. Wing adhesive part; CA. Crotch area; ee. Circular compression part; EL. Linear compression part. Detailed implementation mode

[0029] According to the description of this specification and the drawings, at least the following matters become clear.

[0030] (Mode 1)

[0031] An absorbent article having a length direction, a width direction, and a thickness direction that are orthogonal to each other, comprising: an absorbent core; and a core wrapper sheet provided on the skin side of the absorbent core. The absorbent article is characterized in that the absorbent core has comminuted fibers, the core wrapper sheet has cellulose fibers, and the average fiber length of the comminuted fibers is shorter than the average fiber length of the cellulose fibers.

[0032] According to Mode 1, compared with the case where the average fiber length of the comminuted fibers is longer than the average fiber length of the cellulose fibers, there are more contact points where excrement contacts the comminuted fibers inside the absorbent core. Therefore, it is easy to transfer excrement along the fibers from the skin side to the non-skin side in the thickness direction in the absorbent core.

[0033] (Mode 2)

[0034] The absorbent article according to Mode 1, characterized in that the absorbent article has a plurality of absorbent body compression parts formed by compressing the absorbent core and the core wrapper sheet in the thickness direction, the length of the absorbent body compression part in the width direction is larger than the average fiber width of the comminuted fibers, and the absorbent article has a part where the absorbent body compression part overlaps with a plurality of the comminuted fibers when viewed in the thickness direction.

[0035] According to Mode 2, since it is possible to provide parts where the density of the comminuted fibers of the absorbent core is locally increased, it is easy to suck excrement from the core wrapper sheet into the absorbent core and easy to promote the absorption of the absorbent core.

[0036] (Mode 3)

[0037] The absorbent article according to Mode 2 is characterized in that the absorbent article has a plurality of the absorbent body compression parts and a central compression part formed by compressing the absorbent core and the core wrap sheet in the thickness direction, the central compression part is arranged along the length direction and at the central part in the width direction, and a plurality of the absorbent body compression parts are provided on both sides in the width direction of the central compression part.

[0038] According to Mode 3, by having the central compression part, the absorbent core is deformed in such a way that the central part in the width direction protrudes toward the skin side, promoting diffusion along the length direction, and it is easy to promote diffusion in the absorbent core by using the absorbent body compression parts. In addition, it is easy to suppress the deformation of the shape of the absorbent core by using the central compression part and the absorbent body compression parts.

[0039] (Mode 4)

[0040] The absorbent article according to any one of Modes 1 to 3 is 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.

[0041] According to Mode 4, compared with 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, the contact part between the absorbent core and the core wrap sheet can be reduced, so it is easy to promote the absorption of excrement from the state where it has diffused in the core wrap sheet along the thickness direction into the absorbent core, and thus it is easy to increase the absorption speed of excrement.

[0042] (Mode 5)

[0043] The absorbent article according to any one of Modes 1 to 4 is characterized in that the absorbent core has a superabsorbent polymer, and the cellulose fiber has such fibers that the average fiber length is larger than the average value of the diameters of the superabsorbent polymer in the state not impregnated with physiological saline and smaller than the average value of the diameters of the superabsorbent polymer in the state after being dehydrated for 15 minutes after being impregnated with the physiological saline for 60 minutes.

[0044] According to Mode 5, the possibility that the core wrap sheet hinders the swelling of the superabsorbent polymer can be reduced, and it is easy to exert the absorption function of the superabsorbent polymer in the absorbent core.

[0045] (Mode 6)

[0046] The absorbent article according to any one of Modes 1 to 5, wherein the core wrap sheets have an overlapping portion where the core wrap sheets overlap each other at a position closer to the skin side than the absorbent core, and 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 is arranged along the length direction, the length of the overlapping portion in the width direction is longer than the average fiber length of the shredded fibers, and the length of the overlapping portion in the width direction is longer than the average fiber length of the cellulose fibers.

[0047] According to Mode 6, the core wrap sheets are not adhered to the absorbent core and are not adhered to each other in the overlapping portion, thereby delaying the penetration of excrement in the overlapping portion in the thickness direction and facilitating the planar diffusion of excrement in the core wrap sheets, particularly the diffusion along the length direction. Therefore, it is easy to retain the excrement absorbed by the absorbent core in a larger range within the absorbent core.

[0048] (Mode 7)

[0049] The absorbent article according to any one of Modes 1 to 6, wherein the weight ratio of the fibers along the length direction in the shredded fibers is larger than the weight ratio of the fibers along the length direction in the cellulose fibers.

[0050] According to Mode 7, it is easy to diffuse excrement in the core wrap sheets in the length direction and the width direction and in the absorbent core in the length direction, thereby reducing the possibility of excrement leaking to the outside in the width direction of the absorbent article.

[0051] (Mode 8)

[0052] The absorbent article according to any one of Modes 1 to 7, wherein the average fiber width of the shredded fibers is larger than the average fiber width of the cellulose fibers.

[0053] According to Mode 8, compared with the case where the average fiber width of the shredded fibers is smaller than the average fiber width of the cellulose fibers, it is easier to retain liquid in the absorbent core than in the core wrap sheets. Therefore, the possibility of excrement leaking from the absorbent article can be reduced.

[0054] (Mode 9)

[0055] The absorbent article according to any one of Modes 1 to 8, characterized in that the absorbent article has: a plurality of absorbent body compression parts, which are formed by compressing the absorbent core and the core wrapper in the thickness direction; and a non-compression part, which is a part where the absorbent core and the core wrapper overlap when viewed in the thickness direction and where the absorbent body compression part is not provided, and the number of fiber masses in the non-compression part of the absorbent core, which have a density higher than the average density of the absorbent core and in which the crushed fibers are dense, is larger than the number of fiber masses in the non-compression part of the core wrapper, which have a density higher than the average density of the core wrapper and in which the cellulose fibers are dense.

[0056] According to Mode 9, in the core wrapper, it is easier for excrement to spread over a larger area compared to the absorption of excrement, and the number of fiber masses in the absorbent core is larger, so that the absorption and liquid retention in the absorbent core can be improved by capillary action.

[0057] (Mode 10)

[0058] The absorbent article according to Mode 9, characterized in that the number of fiber masses in the non-compression part of the core wrapper, which have a density higher than the average density of the core wrapper and in which the cellulose fibers are dense, is zero.

[0059] According to Mode 10, in the core wrapper, it is easier for excrement to spread over a larger area compared to the absorption of excrement, and the number of fiber masses in the absorbent core is larger, so that the absorption and liquid retention in the absorbent core can be improved by capillary action.

[0060] (Mode 11)

[0061] The absorbent article according to any one of Modes 1 to 10, characterized in that the absorbent article has: a plurality of absorbent body compression parts, which are formed by compressing the absorbent core and the core wrapper in the thickness direction; and a non-compression part, which is a part where the absorbent core and the core wrapper overlap when viewed in the thickness direction and where the absorbent body compression part is not provided, and in the non-compression 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 dense, the absorbent core has a skin side part, a middle part, and a non-skin side part when the absorbent core is divided into three equal parts in the thickness direction, and the number of fiber masses in the middle part, in which the crushed fibers are dense, is larger than the number of fiber masses in the skin side part, in which the crushed fibers are dense.

[0062] According to Mode 11, it is easy to inhale excrement from the skin side part of the absorbent core into the middle part, and it is easy to suppress the situation where the excrement temporarily absorbed by the middle part returns to the skin side part.

[0063] (Mode 12)

[0064] The absorbent article according to any one of Modes 1 to 11, characterized in that the absorbent article has: a plurality of absorbent body compression parts, which are formed by compressing the absorbent core and the core wrapping sheet in the thickness direction; and a non-compression part, which is a part where the absorbent core and the core wrapping sheet overlap when viewed in the thickness direction and where the absorbent body compression part is not provided. In the non-compression part 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 crushed fibers are dense. When the absorbent core is equally divided into three parts in the length direction and the width direction respectively, it has a side part, a central part, and the other side part in sequence from one side. The number of fiber masses in which the crushed fibers are dense in the central part is larger than the number of fiber masses in which the crushed fibers are dense in the side part.

[0065] According to Mode 12, the absorbency of the part close to the wearer's excretory opening can be improved.

[0066] (Mode 13)

[0067] The absorbent article according to any one of Modes 1 to 12, characterized in that the crushed fibers contain hardwood fibers formed from hardwood, and the weight ratio of the hardwood fibers to the crushed fibers is 85% or more.

[0068] According to Mode 13, in the absorbent core, there are parts where it is easy to form fiber masses in which the crushed fibers are dense and the fiber density is high, and parts where the fiber density is lower than that of the fiber masses. Thus, while improving the absorbency based on capillary action in the parts of the fiber masses, it is easy to retain excrement in the gaps between the fibers in the parts where the fiber density is lower than that of the fiber masses, so it is easy for the absorbent core to efficiently absorb excrement.

[0069] (Mode 14)

[0070] The absorbent article according to any one of Modes 1 to 13, characterized in that the core wrapping sheet contains a paper strength enhancer, and the absorbent core does not contain the paper strength enhancer.

[0071] According to Mode 14, a paper strength enhancer is provided in the core wrapping sheet to improve the strength of the core wrapping sheet, and the possibility of the decrease in water retention of the absorbent core due to the paper strength enhancer is reduced. The absorbent core with the decreased water retention is covered by the core wrapping sheet with improved strength, so it is easy to maintain the shape of the absorbent core.

[0072] ===This Embodiment===

[0073] Hereinafter, as an example of the absorbent article of the present embodiment, a sanitary napkin for menstruation will be cited for illustration. However, the absorbent article for menstruation is not limited to a sanitary napkin for menstruation, and may also be a panty liner, a disposable diaper of the panties type, a disposable diaper of the belt type, etc., an absorbent pad, etc.

[0074] <<<Structure of the sanitary napkin 1 of the present embodiment>>>

[0075] Figure 1 It is a top view obtained by observing the sanitary napkin 1 from the skin side. Figure 2 It is a top view obtained by observing the sanitary napkin 1 from the non-skin side. Figure 3 It is Figure 1 A schematic cross-sectional view taken along the line A - A in. The sanitary napkin 1 has a length direction, a width direction, and a thickness direction. On the length direction, the side that abuts against the lower abdomen of the wearer is set as the front side, and the side that abuts against the buttocks of the wearer is set as the rear side. On 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. Figure 1 The center line C - C shown in etc. represents the center in the width direction of the sanitary napkin 1, and the center line CL represents the center in the length direction of the sanitary napkin 1. Figure 3 The cross-sectional views such as etc. schematically show the sanitary napkin 1, and the dimensions are not necessarily correct.

[0076] The sanitary napkin 1 has an absorbent body 10, a topsheet 21, a pair of side sheets 23, and a backsheet 31. It may also be that in the region closer to the skin side than the absorbent body 10, a sheet-like second sheet 22 is provided at a position closer to the non-skin side than the topsheet 21. The respective raw materials adjacent to each other in the thickness direction are joined by an adhesive such as hot melt adhesive.

[0077] The sanitary napkin 1 has a pair of wing portions 1W that extend outward in the width direction at the central portion in the length direction. The wing portions 1W are mainly formed by the side sheets 23 and the backsheet 31. In addition, it may also be a structure that does not necessarily have the wing portions 1W.

[0078] The topsheet 21 is a liquid-permeable sheet material located at a position closer to the skin side than the absorbent body 10. The topsheet 21 is a surface sheet that is located at a position closer to the skin side than the absorbent body 10 and can abut against the skin of the wearer. As the topsheet 21, examples include non-woven fabrics (such as hot air non-woven fabrics, spunbond non-woven fabrics, etc.) formed of synthetic fibers such as polyethylene (PE) and polypropylene (PP), synthetic resin films having through holes, and non-woven fabric sheets formed of cotton. The topsheet 21 of the present embodiment is formed of a liquid-permeable sheet material of a hot air non-woven fabric or a hydroentangled non-woven fabric containing polyethylene terephthalate (PET) and polyethylene (PE), or water-retaining fibers such as cotton and rayon.

[0079] A pair of side sheets 23 are provided at a position closer to the non-skin side than the top sheet 21 and the second sheet 22 and closer to the skin side than the absorbent body 10, and are sheet materials extending outward from both side portions in the width direction of the top sheet 21 and the like. As the side sheet 23, examples include a soft liquid-permeable non-woven fabric, a hydrophobic non-woven fabric, etc. that are the same as the top sheet 21. In addition, a reinforcing sheet 24 for strengthening the strength of the side sheet 23 is provided at a position outside the top sheet 21, the second sheet 22, and the absorbent body 10 in the width direction and between the side sheet 23 and the bottom sheet 31 in the thickness direction. As the reinforcing sheet 24, for example, a sheet member, paper, SMS, etc. that are the same as the bottom sheet 31 can be used.

[0080] The bottom sheet (non-skin side sheet) 31 is a sheet material located closer to the non-skin side than the absorbent body 10 and provided at the outermost non-skin side position of the sanitary napkin 1. As the bottom sheet 31, examples include a liquid-impermeable sheet material such as a resin film of polyethylene (PE). The shape of the bottom sheet 31 is substantially the same as the outer shape of the sanitary napkin 1.

[0081] A plurality of main body adhesive portions (adhesive portions) 32 are provided on the non-skin side surface of the bottom sheet 31. The main body adhesive portion 32 of the present embodiment is a plurality of strip-shaped regions coated with a hot melt adhesive along the length direction. When wearing the sanitary napkin 1, by pasting the main body adhesive portion 32 to the inner side of the crotch portion (crotch) of the underwear (clothing), the sanitary napkin 1 can be prevented from being displaced relative to the wearer's body.

[0082] The wing portion 1W has a wing adhesive portion 33 on the non-skin side surface of the bottom sheet 31. The wing adhesive portion 33 of the present embodiment is a rectangular region coated with a hot melt adhesive. When wearing the sanitary napkin 1, by folding the wing portion 1W back to the non-skin side surface of the underwear and pasting the wing adhesive portion 33 to the non-skin side surface of the crotch portion of the underwear, the sanitary napkin 1 can be fixed to the underwear.

[0083] The position overlapping with the wing adhesive portion 33 in the length direction (refer to Figure 1 ) is the crotch region CA. The crotch region CA is a region that abuts against the wearer's crotch in the length direction in the wearing state and is a region that abuts against the blood discharge port where the wearer excretes excrement.

[0084] The absorber 10 has an absorbent core 11 and a core wrapper sheet 12. The absorbent core 11 is formed by shaping liquid-absorbent fibers into a predetermined shape. As the liquid-absorbent fibers, it has shredded fibers. The shredded fibers include hardwood fibers formed from hardwood trees. The absorbent core 11 of the present embodiment includes shredded fibers (pulp fibers), and as the shredded fibers, it is formed only of hardwood fibers (100% hardwood fibers). In addition, the absorbent core 11 is not limited to shredded fibers formed of hardwood fibers, and the shredded fibers may also include pulp fibers such as softwood fibers formed from softwood trees in addition to hardwood fibers. The absorbent core 11 may also include liquid-absorbent fibers such as cellulose-based absorbent fibers, synthetic fibers formed of polyolefins, polyesters, acrylics, acrylates, etc., and superabsorbent polymers (SAP). Figure 4A is a top view of the absorbent core 11. Figure 4B is Figure 4A a schematic cross-sectional view taken along the line J-J in Figure 5 is Figure 4A an enlarged schematic view of the cross-section taken along the line K-K in Figure 6 is Figure 3 an enlarged view of the absorber 10 in Figure 4A , Figure 4B and Figure 5 the unevenness formed by compression portions such as the compression portion EL is omitted in the illustration.

[0085] The absorbent core 11 has a middle-high portion 11d with a higher unit area weight of liquid-absorbent fibers than the surroundings. The middle-high portion 11d is a portion where the thickness of the absorbent core 11 is thicker than the surroundings (longer in the thickness direction). The middle-high portion 11d of the present embodiment is a portion that protrudes toward the skin side in the thickness direction and is a region that is substantially elliptical in plan view. By providing the middle-high portion 11d at the central portion in the width direction of the absorbent core 11 and at a position that overlaps with the crotch region CA in plan view, it is easy to contact the wearer's excretory opening in the wearing state, it is easy to make the sanitary napkin 1 fit to the wearer's body, and it is easy to quickly absorb excreta. In addition, by having the middle-high portion 11d with a relatively high unit area weight of liquid-absorbent fibers at a position that overlaps with the crotch region CA in plan view, it is easy to retain the excreta discharged from the wearer's excretory opening in the absorbent core 11 in the wearing state.

[0086] The core wrapper sheet 12 is a liquid-permeable sheet member. The core wrapper sheet 12 of the present embodiment is a thin paper having cellulose fibers. The core wrapper sheet 12 maintains the shape of the absorbent core 11 or promotes the diffusion of liquid into the absorbent core 11 by covering the absorbent core 11.

[0087] As shown in Figure 6As shown, the core wrapper sheet 12 has a skin-side portion 12a located on the skin side of the absorbent core 11 and a non-skin-side portion 12b located on the non-skin side of the absorbent core 11. In the present embodiment, as Figure 6 shown, etc., by folding the both side ends of the core wrapper sheet 12 toward the skin side of the absorbent core 11, the skin side surface and the non-skin side surface of the absorbent core 11 are covered by the core wrapper sheet 12. Specifically, the core wrapper sheet 12 wraps the absorbent core 11 in such a manner that the tip 12ea along the length direction of the core wrapper sheet 12 is set to the outside and the other tip 12eb along the length direction is set to the inside to cover the side ends in the width direction of the absorbent core 11. However, the shape and form of the core wrapper sheet 12 are not limited thereto. For example, it may also be a structure in which the core wrapper sheet 12 is made into two sheet members and they are respectively arranged on the skin side and the non-skin side of the absorbent core 11. In addition, no adhesive is provided inside the core wrapper sheet 12 of the present embodiment. That is, the absorbent core 11 is not fixed using an adhesive between the absorbent core 11 and the core wrapper sheet 12, and the absorbent core 11 maintains its shape by being wrapped by the core wrapper sheet 12.

[0088] Figure 7 is a plan view of the absorbent body 10 as viewed from the skin side. In Figure 7 the middle height portion 11d of the absorbent core 11 is omitted from the illustration. As Figure 7 shown, the absorbent body 10 has a central compression portion 14 and a plurality of absorbent body compression portions 15. The central compression portion 14 and the absorbent body compression portions 15 are portions formed by compressing the absorbent core 11 and the core wrapper sheet 12 in the thickness direction, respectively.

[0089] The central compression portion 14 and the absorbent body compression portions 15 are formed, for example, by passing the absorbent body 10 during the manufacturing process through the roll gap between a convex roll having a plurality of convex portions and an anvil roll with a flat surface to compress it. The central compression portion 14 and the absorbent body compression portions 15 of the present embodiment are portions formed by pressing the absorbent body 10 from the non-skin side toward the skin side while the convex roll abuts against the non-skin side surface of the absorbent body 10 and the anvil roll abuts against the skin side surface.

[0090] The central compression portion 14 is a linear compression portion that extends along the length direction and is provided at the central portion in the width direction. The central compression portion 14 is a portion that is recessed in the thickness direction from the skin side or the non-skin side within the range from the front end to the rear end of the absorbent body 10. The central compression portion 14 is a guiding portion that guides the absorbent body 10 to bend toward the skin side in the thickness direction starting from the central compression portion 14. In addition, since the central compression portion 14 has a higher fiber density than the uncompressed portion, it is also a guiding portion that guides excrement along the length direction by capillary action.

[0091] The absorber compression part 15 is a compression part arranged in a substantially staggered pattern over the entire area of the absorber 10. The absorber compression part 15 of the present embodiment is provided with a plurality of elliptical compression parts. The absorber compression part 15 is also a part that is recessed in the thickness direction from the skin side or the non-skin side, similar to the central compression part 14. By providing the absorber compression part 15, it becomes easy to maintain the shape of the absorber 10. In addition, the absorber compression part 15 is a part where the fiber density is higher than that of the uncompressed part, so it becomes a part that easily absorbs excrement in the absorbent core 11 by capillary action. Due to the density difference between the absorber compression part 15 and the uncompressed part, it is easy to suppress the diffusion of the oil agent Y in the absorbent core 11 described later.

[0092] In addition, as Figure 1 shown, etc., the sanitary napkin 1 has a linear compression part EL and a circular compression part ee.

[0093] The linear compression part EL is a part formed by compressing at least a part of the topsheet 21, the second sheet 22, and the absorber 10 in the thickness direction. The linear compression part EL of the sanitary napkin 1 of the present embodiment has a front compression part Ela provided at a position forward of the center line CL in the length direction, a rear compression part ELb provided at a position rearward of the center line CL, and a central compression part ELc provided between the front compression part Ela and the rear compression part ELb. By providing the linear compression part EL, the bonding in the thickness direction of each member can be made firm, the fiber density can be increased, and the liquid absorbency can be improved. The linear compression part EL is a linear compression part along the length direction in a plan view, and a pair is provided at a predetermined interval in the width direction.

[0094] A plurality of circular compression parts ee are provided at the central part in the width direction and at a position overlapping the crotch region CA in the length direction. The circular compression part ee is a compression part having a circular shape in a plan view, and is a part formed by compressing at least a part of the topsheet 21, the second sheet 22, and the absorber 10 in the thickness direction.

[0095] Since the linear compression part EL and the circular compression part ee are parts formed by flattening the members overlapping in the thickness direction, the fiber density of each member at each compression part is higher than that of the part where the compression part is not provided. The linear compression part EL and the circular compression part ee are formed, for example, by passing the sanitary napkin 1 during the manufacturing process through the roll gap between a convex roll having a plurality of convex parts and an anvil roll having a flat surface and compressing it.

[0096] <<<Regarding the absorber 10>>>

[0097] The absorbent body 10 of the sanitary napkin 1 includes an absorbent core 11 and a skin-side portion 12a of the core wrapper 12 disposed at a position closer to the skin side than the absorbent core 11. The absorbent core 11 has shredded fibers 11f, and the skin-side portion 12a (core wrapper 12) has cellulose fibers 12f. Moreover, the average fiber length of the shredded 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.

[0098] The absorbent core 11 has shredded fibers 11f. Examples of the shredded 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. Most absorbent articles use coniferous tree fibers (coniferous tree pulp) with relatively long fiber lengths. In contrast, the shredded fibers 11f of the absorbent core 11 of the present embodiment are composed only of broad-leaved tree fibers (broad-leaved tree pulp) (100% broad-leaved tree fibers).

[0099] Figure 8 It is a graph showing the distribution of the fiber lengths of broad-leaved tree fibers and coniferous tree fibers. The average fiber length of the coniferous tree fibers (coniferous tree pulp) is 2.5 mm, and the average fiber length of the broad-leaved tree fibers (broad-leaved tree pulp) is 0.79 mm. That is, the average fiber length of the broad-leaved tree fibers is shorter than the average fiber length of the coniferous tree fibers.

[0100] The skin-side portion 12a (core wrapper 12) has cellulose fibers 12f. The cellulose fibers 12f are fibers made from wood or recycled paper and are fibers mainly composed of cellulose. The core wrapper 12 of the present embodiment is thin paper. Examples of the fibers constituting the thin paper include waste paper pulp regenerated from wood pulp waste paper derived from coniferous trees or broad-leaved trees, non-wood pulp made from plants such as kenaf or bamboo, synthetic fiber pulp, etc. The thin paper of the skin-side portion 12a of the present embodiment is configured such that the weight ratio of the coniferous tree fibers derived from coniferous trees is 60% to 70%, and the weight ratio of the broad-leaved tree fibers derived from broad-leaved trees is 30% to 40%, containing a relatively large amount of coniferous tree fibers with a relatively long average fiber length. In addition, the average fiber length of the cellulose fibers of the skin-side portion 12a is 1.8 mm.

[0101] Figure 9 It is an enlarged schematic view illustrating the absorption of excrement by the absorbent body 10. Figure 9 It is a schematic view showing a part of the skin-side portion 12a and a part of the absorbent core 11 in an enlarged manner. For convenience, the overlapping portions of the core wrapper 12 (skin-side portion 12a) with each other at a position closer to the skin side than the absorbent core 11 and the middle-high portion 11d of the absorbent core 11 are omitted in the illustration.

[0102] The longer the length of the fibers, the easier it is for the excrement (liquid) to spread along the fibers. In addition, the shorter the length of the fibers, the easier it is for the distance between the fibers to be shorter. The average fiber length of the shredded 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, so that it is easier for the excrement to spread horizontally in the skin side portion 12a than in the case where the average fiber length of the shredded fibers 11f is longer than the average fiber length of the cellulose fibers 12f. When the excrement that has spread in the skin side portion 12a reaches the absorbent core 11, there are more contact points where the excrement contacts the shredded fibers 12f inside the absorbent core 11. Therefore, it is easier for the excrement to transfer from the skin side in the thickness direction to the non-skin side in a manner of flowing along the shredded fibers 11f and falling between the shredded fibers 11f. Specifically, when wearing, if excrement such as menstrual blood is discharged into the crotch area CA, it is first easy to spread from the crotch area CA toward the outside in the skin side portion 12a having cellulose fibers 12f with a relatively long average fiber length. If the spread excrement transfers from the skin side portion 12a to the absorbent core 11, the excrement moves between the shredded fibers 11f with a shorter average fiber length in a manner of falling from the skin side to the non-skin side. Therefore, it is possible to reduce the possibility that the excrement remains on the skin side of the crotch area CA and causes an adverse effect or discomfort to the wearer's skin.

[0103] The fibers of the skin side portion 12a (core wrapping sheet) can be taken out, for example, by the following method.

[0104] First, decompose the sanitary napkin 1 using toluene to take out the core wrapping sheet 12.

[0105] Dry the taken-out core wrapping sheet.

[0106] Then, put the core wrapping sheet 15g and about 1.5 L of water (adjust the water so that the concentration relative to the weight of the core wrapping sheet is 1%) into a plastic container (inner diameter: 120 mm, height: 220 mm), and stir with a blender (EYELA MAZELAZ manufactured by Tokyo Rika Kikai Co., Ltd.) at room temperature for about 24 hours. At this time, stir slowly so that the fibers do not break.

[0107] After that, suck up the fibers dispersed in the water together with the water using a straw (aperture: 2 mm to 3 mm).

[0108] Collect the taken-out fibers by suction filtration and dry them.

[0109] Measure the fiber length of the taken-out fibers using an electron microscope, and calculate the average fiber length based on the measured fiber length.

[0110] In addition, the average fiber length of the shredded fibers of the absorbent core 11 and the average fiber length of the fibers of the skin side portion 12a can be measured by well-known methods. For example, they can be obtained by taking an image using the above-described fiber length distribution measuring device (“Valmet FS5” manufactured by Valmet Corporation) and measuring the fiber length.

[0111] In addition, it is sufficient that the average fiber length of the shredded 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, and any shredded fibers (such as softwood fibers and hardwood fibers) can be used. In addition, considering that the average fiber length of the shredded fibers 11f is shorter than the average fiber length of the cellulose fibers 12f, the shredded fibers 11f preferably include hardwood fibers.

[0112] Preferably, as Figure 7 shown, the sanitary napkin 1 (absorbent body 10) has a plurality of absorbent body compression portions 15 formed by compressing the absorbent core 11 and the skin side portion 12a (core wrapping sheet 12) in the thickness direction. Preferably, the length W15 in the width direction of the absorbent body compression portion 15 is larger than the average fiber width of the shredded fibers 11f, and there is a portion where the absorbent body compression portion 15 and a plurality of shredded fibers 11f overlap when viewed in the thickness direction. In addition, when there are absorbent body compression portions 15 having different lengths in the width direction among the plurality of absorbent body compression portions 15, it is sufficient that the absorbent body compression portion 15 having the longest length in the width direction has a length W15 larger than the average fiber width of the shredded fibers 11f. In the present embodiment, the length W15 in the width direction of the absorbent body compression portion 15 is 0.5 mm to 1.0 mm, and the shredded fibers 11f are hardwood fibers. Therefore, the average fiber width of the hardwood fibers is about 15 μm. Figure 10 is a graph showing the distribution of the average fiber widths of hardwood fibers and softwood fibers.

[0113] The absorbent body compression portion 15 is a portion where the fiber density is increased by compression. Therefore, by having a portion where the absorbent body compression portion 15 overlaps with a plurality of shredded fibers 11f, it is possible to provide portions where the fiber density of the shredded fibers 11f of the plurality of absorbent cores 11 is locally increased. As a result, by capillary action, it is easy to suck excrement from the skin side portion 12a toward the absorbent core 11, and it is easy to promote the absorption of excrement by the absorbent core 11.

[0114] The average fiber width of the shredded fibers 11f can be measured by well-known methods. For example, it can be measured by the following method.

[0115] A portion (absorbent core 11) equivalent to a sample of the object to be measured is cut into a quadrilateral shape as a test specimen, and a magnified image with a focal depth of 100 μm from the surface of the test specimen is obtained using the 3D image connection function of a microscope (KEYENCE VHX-2000, lens VH-Z20W with aperture open) (for example, an image magnified 500 times for hardwood fibers and 100 times for softwood fibers), and the fiber widths of multiple fibers in this image are measured to calculate the average fiber width.

[0116] It is also preferable that the sanitary napkin 1 (absorbent body 10) has a central compression portion 14 in addition to the multiple absorbent body compression portions 15. The central compression portion 14 is provided along the length direction and at the central portion in the width direction. Preferably, a plurality of absorbent body compression portions 15 are provided on both sides in the width direction of the central compression portion 14. With such an absorbent body 10, the central compression portion 14 deforms the absorbent core 11 so that the central portion in the width direction of the absorbent body 10 protrudes toward the skin side, which facilitates the diffusion of excrement along the length direction. In addition, it is easy to promote the diffusion within the absorbent core 11 (absorbent body 10) by the absorbent body compression portions 15. Further, since the central compression portion 14 and the absorbent body compression portions 15 are respectively portions formed by compressing the skin side portion 12a and the absorbent core 11 in the thickness direction, by providing these compression portions 14 and 15, it is easy to suppress the deformation of the shape of the absorbent core 11.

[0117] The skin side portion (core wrapper) 12a of the core wrapper 12 located on the skin side of the absorbent core 11 Figure 6 ) Preferably, 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, preferably, 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 Figure 9 shown, starting from the state where excrement is temporarily diffused horizontally in the skin side portion 12a, compared with promoting the further horizontal diffusion of excrement, it is easier to promote the transfer of excrement from the skin side portion 12a to the absorbent core 11 in the thickness direction (toward the non-skin side) and the absorption within the absorbent core 11. Therefore, by promoting the diffusion of excrement absorbed on the skin side surface of the sanitary napkin 1 in the skin side portion 12a and the absorption in the thickness direction of the absorbent core 11 during wearing, the absorption speed of excrement as the sanitary napkin 1 can be increased, and the possibility that excrement remains on the skin side surface of the sanitary napkin 1 and has an adverse effect on the wearer's skin or causes discomfort can be reduced.

[0118] Preferably, as Figure 6As shown in the figure, the core wrap sheet 12 (skin side portion 12a) has an overlapping portion 12r formed by overlapping the core wrap sheets 12 at a position closer to the skin side than the absorbent core 11. In the present embodiment, in the skin side portion 12a, as Figure 6 and Figure 7 shown, the core wrap sheet 12 covers the non-skin side surface of the absorbent core 11, and folds back both end portions of the core wrap sheet 12 toward the skin side of the absorbent core 11. The tip 12ea along the length direction that is folded back from the other side in the width direction toward the skin side is set as the outer side (skin side), and the tip 12eb along the length direction that is folded back from one side in the width direction toward the skin side is set as the inner side (non-skin side). The tip 12ea is arranged at a position on one side in the width direction closer than the tip 12eb, so that the overlapping portion 12r is provided in the skin side portion 12a.

[0119] In the case where there is an overlapping portion 12r where the core wrap sheets 12 of the sanitary napkin 1 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. Preferably, as Figure 7 shown, the overlapping portion 12r is provided at the central portion in the width direction and is arranged along the length direction. Moreover, it is preferable that the length W12r in the width direction of the overlapping portion 12r (in the present embodiment, the length W12r is 5 mm) is longer than the average fiber length of the shredded fibers (in the present embodiment, it is 0.79 mm), and the length W12r in the width direction of the overlapping portion W12r is longer than the average fiber length of the cellulose fibers (in the present embodiment, it is 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 are not in close contact with each other and the skin side portion 12a and the absorbent core 11 are not in close contact. Moreover, since the length W12r in the width direction of the overlapping portion 12r is longer than the average fiber length of the shredded 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 overlapping portion 12r in the thickness direction. Therefore, when excrement is absorbed during wearing, it is easy to promote the planar diffusion of excrement in the core wrap sheet 12. In particular, since the overlapping portion 12r is arranged along the length direction, it is easy to promote the diffusion of excrement along the length direction. Therefore, the excrement that has temporarily diffused in the skin side portion 12a is then transferred to the absorbent core 11 and absorbed, so that it is easy to absorb and retain excrement in a relatively large range within the absorbent core 11.

[0120] When no adhesive is provided between the skin side of the absorbent core 11 and the non-skin side of the skin-side portion 12a, and the absorbent core 11 contains a superabsorbent polymer (hereinafter also referred to as "SAP"), the average fiber length of the cellulose fibers 12f in the skin-side portion 12a is greater than the average particle diameter of the superabsorbent polymer in a state where it is not impregnated with physiological saline. It is also preferable that the average fiber length of the cellulose fibers 12f in the skin-side portion 12a is smaller than the average particle diameter of the superabsorbent polymer in a state where water removal has been performed for 15 minutes after impregnation with physiological saline for 60 minutes.

[0121] By having the average fiber length of the cellulose fibers 12f in the skin-side portion 12a greater than the average particle diameter of the superabsorbent polymer in a state where it is not impregnated with physiological saline, that is, before absorbing excrement, and having the average fiber length of the cellulose fibers 12f in the skin-side portion 12a smaller than the average particle diameter of the superabsorbent polymer in a state where it has been impregnated with physiological saline, that is, after absorbing excrement, the possibility that the skin-side portion 12a hinders the swelling of the superabsorbent polymer can be reduced, and it is easy to exhibit the water absorption function and water retention function of the superabsorbent polymer.

[0122] Figure 11 It is a table showing the change in the diameter of SAP when swelling SAP at a predetermined water absorption ratio and water retention ratio. In Figure 11 it, the SAP particle diameter shown at the left end represents the particle diameter of SAP before swelling, and the SAP diameter shown on the right represents the average particle diameter (average diameter) of SAP after swelling corresponding to the water supply ratio (water retention ratio). Specifically, it shows the result obtained by calculating the average value of the diameters of each SAP when SAP with a particle diameter (diameter) of 150 μm to 850 μm before swelling absorbs (dehydrates) water (physiological saline) at a water absorption ratio (water retention ratio) of 10 times to 120 times. Here, the "water absorption ratio" is the value obtained by dividing the saturated amount of water that can be absorbed and retained by a water-absorbing medium such as SAP by the weight of the water-absorbing medium before water absorption. In addition, the "water retention ratio" is the value obtained by dividing the amount of water that can be retained by the water-absorbing medium such as SAP after the water absorbed by the water-absorbing medium such as SAP is dispersed (dehydrated) by the weight of the water-absorbing medium before water absorption.

[0123] Referring to "JIS K 7223-1996 Test Method for Water Absorbency of Superabsorbent Resins" and following the steps below to measure the water absorption ratio (water retention ratio) of SAP.

[0124] First, prepare the SAP to be measured under the conditions of temperature: 20°C, relative humidity: 60%, and pressure (standard atmospheric pressure): 1 atm (101.325 kPa) (for example, in a laboratory maintained at these conditions). Store the SAP in a predetermined container and shake it upside down more than 10 times to evenly mix the SAP particles. Accurately measure 1.00 g of the mixed SAP using a spatula or the like and place it into a separately prepared nylon mesh bag. The nylon mesh bag can be, for example, a bag formed by overlapping two 200 mm × 200 mm square nylon meshes, heat-sealing at positions 5 mm from the ends of three sides of the square, and shaping it into a bag with only one side of the square open. As the nylon mesh, for example, a 250-mesh nylon mesh (N-No. 250HD) manufactured by NBC Industries can be used.

[0125] After placing the SAP into the nylon mesh bag, heat-seal the opening of the nylon mesh bag to enclose the SAP in a way that it does not spill out of the nylon mesh bag. Then, put 1000 ml of physiological saline into a beaker and immerse the nylon bag (with SAP) in the physiological saline such that one side of the nylon bag containing the SAP touches the bottom of the beaker. Then, use a clothespin or the like to fix one side of the upper part of the nylon bag to the edge of the beaker so that the SAP and the nylon mesh do not fit closely as much as possible. Leave it in this state for 60 minutes.

[0126] The physiological saline used is prepared as follows: Place a 3-liter beaker on an electronic balance and zero it. Then, add ion-exchanged water to 27.0 g of sodium chloride (reagent grade 1) to make 3000.0 g, and stir with a stirring rod until the sodium chloride is visually dissolved.

[0127] After leaving it for 60 minutes, lift the nylon bag containing the SAP out of the beaker and hang it in the air in a state where the central upper part of the nylon bag is clamped (for example, at a position 5 mm from the upper end of the nylon bag and 50 mm from both side ends) for 15 minutes to remove water. Then, measure the weight of the nylon bag containing the SAP after 15 minutes. Repeat this experiment multiple times (for example, 5 times), and take the average value of the measured weights as the water absorption weight B.

[0128] Next, dehydrate the dewatered nylon bag (with SAP) using a centrifuge (HI30) manufactured by KOKUSAN Co., Ltd. For example, dehydrate it at a rotational speed of 850 rpm (150G) for 90 seconds. Then, measure the weight of the dehydrated nylon bag (with SAP). Repeat this experiment multiple times (for example, 5 times), and take the average value of the measured weights as the water retention weight C.

[0129] The water absorption of SAP was determined by subtracting the weight K of the nylon mesh obtained through a blank test from the self-water absorption weight B, and the water absorption ratio of SAP was calculated by dividing the water absorption by the sample weight (1.00 g). Similarly, the water retention of SAP was determined by subtracting the weight K' of the nylon mesh obtained through a blank test from the self-water retention weight C, and the water retention ratio of SAP was calculated by dividing the water retention by the original sample weight (1.00 g).

[0130] In addition, a microscope was used to measure the diameter (particle diameter) of SAP before swelling and the diameter (particle diameter) after swelling. Then, based on the relationship between the measured results of the water absorption ratio (water retention ratio) of SAP and the measured diameter (particle diameter), a table showing the relationship between the water absorption ratio of SAP and the diameter (particle diameter) before and after swelling was made ( Figure 11 ).

[0131] As Figure 11 shown, in the range where the water absorption ratio (water retention ratio) of SAP is 10 to 120 times, the average diameter (average particle diameter) of SAP after swelling (after water absorption or dehydration) is larger than the diameter of SAP before swelling (150 μm to 850 μm). For example, in Figure 11 , when the absorption ratio (water retention ratio) is 40 times, the diameter of SAP after swelling (after water absorption) is 2.12 mm with respect to the diameter of SAP before swelling being 500 μm (0.5 mm). In addition, in Figure 11 , when the water absorption ratio and the water retention ratio are the same multiple, the average diameter of SAP after swelling is also the same value. The reason is that the diameter of SAP after swelling is limited by the amount of water (physiological saline in this embodiment) retained in the SAP. That is, if the amount of water retained by SAP after dehydration is equal to the amount of water retained by SAP after water absorption, the average diameter of SAP is also equal.

[0132] As described above, the average fiber length of the cellulose fibers in the skin side portion 12a is 1.8 mm. As Figure 11 shown, it can be seen that there are cases where the particle diameter (particle size) of the superabsorbent polymer after swelling is larger than the average fiber length (1.8 mm) of the cellulose fibers in the skin side portion 12a.

[0133] Figure 12 is a table showing the particle size distribution of the SAP used in this embodiment. As Figure 12As shown, in the case of the SAP used in this embodiment, 79% (average value) of the SAP with a particle diameter before swelling in the range of 250 μm to 600 μm accounts for the whole, 12% (average value) of the SAP with a particle diameter in the range of 600 μm to 850 μm accounts for the whole, and 0% (average value) of the SAP with a particle diameter of 850 μm or more. In addition, 10% (average value) of the SAP with a particle diameter in the range of 0 μm to 250 μm accounts for the whole. Therefore, according to Figure 11 the data, it can be known that about 32% of the SAP contained in the absorber 10 of this embodiment is such that the average particle diameter (particle size) of the swollen superabsorbent polymer is larger than the average fiber length (1.8 mm) of the cellulose fibers.

[0134] By having the average particle diameter of the swollen superabsorbent polymer larger than the average fiber length of the cellulose fibers in the skin-side portion 12a in this way, the water absorption performance of the SAP can be improved. That is, by having the average value of the fiber length of the cellulose fibers in the skin-side portion 12a smaller than the average value of the diameter of the SAP (superabsorbent polymer) in the state after 15 minutes of water removal after being immersed in physiological saline for 60 minutes, the water absorption of the absorber 10 can be improved.

[0135] It is also 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 in the skin-side portion 12a. In this embodiment, the average fiber width of the crushed fibers 11f of the absorbent core 11 is about 15 μm. The larger the average fiber width, the higher the retention of excrement (liquid). Therefore, by having the average fiber width of the crushed fibers 11f of the absorbent core 11 larger than the average fiber width of the cellulose fibers 12f in the skin-side portion 12a, compared with the case where the average fiber width of the crushed fibers 11f is smaller than the average fiber width of the cellulose fibers 12f, the liquid retention property of the absorbent core 11 is more likely to be higher than the liquid retention property of the skin-side portion 12a. As a result, it is easy for the absorbent core 11 to absorb the excrement absorbed from the skin-side portion 12a, reducing the possibility of excrement remaining in the skin-side portion 12a. By being able to easily retain excrement by the absorbent core 11, the possibility of excrement leaking from the sanitary napkin 1 can be reduced.

[0136] Preferably, the weight ratio of the fibers along the longitudinal direction in the comminuted fibers 11f of the absorbent core 11 is larger than the weight ratio of the fibers along the longitudinal direction in the cellulose fibers 12f of the skin-side portion 12a. That is to say, the weight ratio of the fibers along the width direction in the cellulose fibers 12f of the skin-side portion 12a is larger than that in the comminuted fibers 11f. The cellulose fibers 12f of the skin-side portion 12a of the present embodiment are randomly arranged along the longitudinal direction and the width direction, and the weight ratio of the fibers along the longitudinal direction in the comminuted fibers 11f of the absorbent core 11 is larger than the weight ratio of the fibers along the width direction. Excrement is likely to spread along the fibers. Therefore, in the skin-side portion 12a, it is easy to make excrement spread in the longitudinal direction and the width direction by using the cellulose fibers 12f, and in the absorbent core 11, it is easy to make excrement spread in the longitudinal direction by using the comminuted fibers 11f. As a result, as the sanitary napkin 1 as a whole, the possibility of excrement leaking to the outside in the width direction can be reduced.

[0137] Preferably, the skin-side portion 12a (core wrapper 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 agent that is used to bond pulp fibers to make paper that is strengthened so as not to break easily due to liquid, has an improved skin feel, is soft and elastic. As a paper strength enhancer, for example, polyamide epichlorohydrin (PAE) etc. can be cited. By providing this paper strength enhancer in the skin-side portion 12a (core wrapper 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 possibility of a decrease in the water retention of the absorbent core 11 can be reduced. That is to say, by covering the absorbent core 11, which has a reduced water retention due to not having a paper strength enhancer, with the skin-side portion 12a, whose strength is improved due to having a paper strength enhancer, it is easy to maintain the shape of the absorbent core 11.

[0138] Preferably, in the absorbent core 11, broadleaf tree fibers formed from broadleaf trees are included in the comminuted fibers 11f. Moreover, the weight ratio of the broadleaf tree fibers to the comminuted fibers in the absorbent core 11 is preferably 85% or more. In conventional absorbent articles such as sanitary napkins 1, coniferous tree fibers having a relatively long average fiber length are usually used as the comminuted fibers. In contrast, in the absorbent core 11 of the sanitary napkin 1 of the present embodiment, broadleaf tree fibers are used as the comminuted fibers 11f, and the comminuted fibers 11f of the absorbent core 11 are composed of 100% broadleaf tree fibers. The larger the weight ratio of the broadleaf tree fibers having a relatively short average fiber length in the comminuted fibers 11f in the absorbent core 11, the easier it is to form a fiber mass fk in which the comminuted fibers are dense inside the absorbent core 11. The absorbent core 11 having the fiber mass fk has a portion with a relatively high fiber density of the fiber mass fk and a portion with a fiber density lower than that of the fiber mass fk. By having such portions with different fiber densities, the absorbency based on capillary action of the portion of the fiber mass fk is improved, and it is easy to hold excrement in the gaps between the fibers in the portion where the fiber density is lower than that of the fiber mass fk. Therefore, it is easy to efficiently absorb excrement in the absorbent core 11.

[0139] In addition, as described above, the sanitary napkin 1 has an absorbent body compression portion 15 formed by compressing the absorbent core 11 and the skin-side portion 12a (core wrapper 12) in the thickness direction. Preferably, when the portion where the absorbent core 11 and the skin-side portion 12a overlap in the thickness direction and the absorbent body compression portion 15 is not provided is defined as the non-compression portion, the number of fiber masses fk in the non-compression portion of the absorbent core 11 is larger than the number of fiber masses in the non-compression portion of the skin-side portion 12a (core wrapper). It is also preferable that the number of fiber masses in the non-compression portion of the skin-side portion 12a (core wrapper 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 comminuted fibers are dense. The fiber mass of the skin-side portion 12a 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 dense.

[0140] By the number of fiber masses fk of the absorbent core 11 being larger than the number of fiber masses of the skin-side portion 12a, it is easier for excrement to spread in a larger horizontal range in the skin-side portion 12a compared to the absorption of excrement and the penetration in the non-skin-side direction in the thickness direction. In addition, in the absorbent core 11 where the number of fiber masses fk is large, the absorption of excrement and the retention of liquid (excrement) in the absorbent core 11 are easily improved by the capillary action of the fiber masses fk.

[0141] In addition, with respect to the non-compressed portion, in the case where the absorber 10 and the sanitary napkin 1 include compression portions such as a central compression portion 14, a linear compression portion EL, and a dot-like compression portion ee in addition to the absorber compression portion 15, the non-compressed portion is the portion where none of these compression portions are provided.

[0142] The fiber mass fk is the portion where the pulp fibers remain in a spherical shape without being pulverized during the manufacturing process. The fiber mass fk is a high-density portion where the pulp fibers are densely packed into a woolly spherical shape. If a fiber mass is provided, the fiber mass fk is a high-fiber-density portion, and the periphery of the fiber mass fk becomes a low-density portion with a lower fiber density than the fiber mass fk. Therefore, a difference in fiber density is generated, and absorption is facilitated through capillary action. In addition, by having the fiber mass fk, in the absorbent core 11 and the core wrapper 12, there are a high-density portion and a low-density portion in the thickness direction. For example, compared with the case where the high-density portions such as the compression portions 14 and 15 are continuous in the thickness direction, it is easier to maintain the thickness (volume) of the member, and it is soft and easy to improve the cushioning property.

[0143] In addition, in the case where the absorbent core 11 has a fiber mass fk in the non-compressed portion, in the non-compressed portion of the absorbent core 11, as Figure 5 shown, 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 sequentially has an upper side portion (skin side portion) 11a, a middle portion 11b, and a lower side portion (non-skin side portion) 11c. In such a case, it is preferable that the number of fiber masses fk in the middle portion 11b is larger than the number of fiber masses fk in the upper side portion 11a. Since the fiber mass fk in the absorbent core 11 is a portion with a relatively high fiber density, by having the number of fiber masses fk in the middle portion 11b larger than the number of fiber masses fk in the upper side portion 11a, it is easier to suck excrement from the upper side portion 11a of the absorbent core 11 to the middle portion 11b, that is, from the skin side in the thickness direction to the non-skin side, and it is easier to suppress the situation where the excrement temporarily absorbed by the middle portion 11b returns to the upper side portion 11a.

[0144] Figure 13 is a diagram for explaining each part in the length direction and width direction of the absorbent core 11. As Figure 13 shown, when the absorbent core 11 is divided into three equal parts in the length direction of the sanitary napkin 1, from the front side (one side) in the length direction, it sequentially has a front side portion (one side portion) Ta, a central portion Tb, and a rear side portion (the other side portion) Tc. In addition, when the absorbent core 11 is divided into three equal parts in the width direction of the sanitary napkin 1, from one side, it sequentially has a left side portion (one side portion) Wa, a central portion Wb, and a right side portion (the other side portion) Wc.

[0145] In such a case, preferably, the number of fiber blocks fk in which the shredded fibers 11f in the central part Tb are dense is larger than the number of fiber blocks fk in which the shredded fibers 11f in the front part Ta are dense, and the number of fiber blocks fk in which the shredded fibers 11f in the central part Wb are dense is larger than the number of fiber blocks fk in which the shredded fibers 11f in the left part Wa are dense. The central part (the part that is the central part Tb and the central part Wb) in the longitudinal direction and the width direction of the absorbent core 11 is the part that is likely to come into contact with the excretion opening such as the vaginal orifice of the wearer during wearing. Therefore, by increasing the number of fiber blocks fk in the central part Tb and the central part Wb, the absorbency of the part close to the excretion opening of the wearer can be improved.

[0146] ==== Other Embodiments ====

[0147] The embodiments of the present invention have been described above. However, the above embodiments are for facilitating the understanding of the present invention, rather than for limiting the interpretation of the present invention. In addition, it goes without saying that the present invention can be changed and improved without departing from its gist, and equivalents thereof are included in the present invention.

Claims

1. An absorbent article having a length direction, a width direction and a thickness direction which are orthogonal to each other, comprising: an absorbent core; as well as The core wrap sheet is provided at a position closer to the skin than the absorbent core, and the absorbent article is characterized in that: The absorbent core has comminuted fibers, The core wrapper comprises cellulose fibers, The average fiber length of the pulverized fibers is shorter than the average fiber length of the cellulose fibers.

2. The absorbent article according to claim 1, wherein The absorbent article has a plurality of absorbent body compression parts formed by compressing the absorbent core and the core wrap sheet in the thickness direction. The length of the compressed portion of the absorbent body in the width direction is greater than the average fiber width of the pulverized fibers. The absorbent article has a portion where the absorbent body compressed portion overlaps with the plurality of pulverized fibers when viewed in the thickness direction.

3. The absorbent article according to claim 2, wherein: The absorbent article comprises a plurality of the absorbent body compression parts and a central compression part formed by compressing the absorbent core and the core wrap sheet in the thickness direction. The central compression portion is arranged along the length direction and in the center of the width direction. A plurality of the absorbent body compressed portions are provided on both sides of the central compressed portion in the width direction.

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

5. The absorbent article according to claim 1 or 2, characterized in that: The absorbent core has a superabsorbent polymer, The cellulose fibers have an average fiber length greater than an average value of diameters of superabsorbent polymers not immersed in saline and smaller than an average value of diameters of superabsorbent polymers immersed in saline for 60 minutes and then dehydrated for 15 minutes.

6. The absorbent article according to claim 1 or 2, characterized in that: The core wrap sheet has an overlapping portion where the core wrap sheets overlap each other at a position closer to the skin side than the absorbent core. In the overlapping portion, no adhesive is provided between the core wrap sheets. The overlapping portion is provided at the center of the width direction and is arranged along the length direction. The length of the overlapping portion in the width direction is longer than the average fiber length of the pulverized fibers, and 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, characterized in that: The weight ratio of the fibers along the longitudinal direction in the pulverized fibers is greater than the weight ratio of the fibers along the longitudinal direction in the cellulose fibers.

8. The absorbent article according to claim 1 or 2, characterized in that: 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, characterized in that: The absorbent article has: a plurality of absorbent body compression parts formed by compressing the absorbent core and the core wrap sheet in the thickness direction; as well as a non-compressed portion, which is a portion where the absorbent core and the core wrap sheet overlap when viewed in the thickness direction and where the absorbent body compressed portion is not provided, The number of fiber blocks in the non-compressed portion of the absorbent core having a density higher than the average density of the absorbent core and densely packed with the crushed fibers is greater than the number of fiber blocks in the non-compressed portion of the core wrap having a density higher than the average density of the core wrap and densely packed with cellulose fibers.

10. The absorbent article according to claim 9, characterized in that The number of fiber blocks in the non-compressed portion of the core wrap sheet, in which the density is higher than the average density of the core wrap sheet and the cellulose fibers are densely packed, is zero.

11. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article has: a plurality of absorbent body compression parts formed by compressing the absorbent core and the core wrap sheet in the thickness direction; as well as a non-compressed portion, which is a portion where the absorbent core and the core wrap sheet overlap when viewed in the thickness direction and where the absorbent body compressed portion is not provided, The non-compressed portion of the absorbent core has a fiber mass having a density higher than an average density of the absorbent core and in which the crushed fibers are densely packed. The absorbent core has a skin-side portion, a middle portion, and a non-skin-side portion when the absorbent core is divided into three equal parts in the thickness direction. The number of the crushed fiber-dense fiber clusters in the middle portion is greater than the number of the crushed fiber-dense fiber clusters in the skin-side portion.

12. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article has: a plurality of absorbent body compression parts formed by compressing the absorbent core and the core wrap sheet in the thickness direction; as well as a non-compressed portion, which is a portion where the absorbent core and the core wrap sheet overlap when viewed in the thickness direction and where the absorbent body compressed portion is not provided, The non-compressed portion of the absorbent core has a fiber mass having a density higher than an average density of the absorbent core and in which the crushed fibers are densely packed. When the absorbent core is divided into three equal parts in the length direction and the width direction, each of the absorbent core has a side portion, a central portion, and another side portion in order from one side. The number of the crushed fiber-dense fiber masses in the central portion is greater than the number of the crushed fiber-dense fiber masses in the one side portion.

13. The absorbent article according to claim 1 or 2, characterized in that: The pulverized fibers include broadleaf fibers formed from broadleaf trees, and the weight ratio of the broadleaf fibers to the pulverized fibers is 85% or more.

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

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