JP7253977B2 - absorbent article - Google Patents

Description

TECHNICAL FIELD The present invention relates to an absorbent article having a flap portion in the rear area corresponding to the buttocks of the wearer.

Women's absorbent articles such as sanitary napkins and panty liners are so-called nighttime napkins, which are designed to be relatively long in the longitudinal direction along the wearer's front-back direction. In general, such night napkins have a pair of rear flaps that protrude greatly outward in both lateral directions in the rear region corresponding to the wearer's buttocks in order to prevent leakage of excrement such as menstrual blood. have.

In general, absorbent articles such as nighttime napkins have a topsheet that is relatively close to the wearer's skin and a backsheet that is relatively far from the wearer's skin. and an absorbent body interposed between the two sheets. Typically, this absorbent is mainly composed of water-absorbing fibers such as wood pulp, and in many cases, it further contains water-absorbing polymer particles.

As a technique for improving the absorbent, for example, Patent Document 1 discloses an absorbent containing thermoplastic resin fibers and cellulose-based water-absorbing fibers, wherein the thermoplastic resin fibers cover the surface of the absorbent on the surface sheet side. and the backsheet-side surface of the absorbent body. According to the absorbent body described in Patent Document 1, the thermoplastic resin fibers function as a skeleton for holding other components of the absorbent body, such as cellulose-based water-absorbent fibers, so it is said to be soft and resistant to twisting. .

Patent Document 2 describes an absorbent body containing a nonwoven fabric piece that includes heat-fusible fibers and is preliminarily bonded to give a three-dimensional structure, and water-absorbing fibers, and the nonwoven fabric piece absorbs Evenly distributed throughout the body. This three-dimensional nonwoven fabric piece is produced by pulverizing the nonwoven fabric into small pieces using a pulverizing means such as a cutter mill method. 3, it has an irregular shape and does not substantially have a portion that can be regarded as a plane. Patent Document 2 describes a preferred form of the absorbent described in the same document, in which pieces of nonwoven fabric are heat-sealed together. According to the absorbent body described in Patent Document 2, since the nonwoven fabric pieces have a three-dimensional structure, voids are formed inside the absorbent body, and the resilience is improved when water is absorbed. As a result, the water absorption performance is improved. It is said that

Patent Document 3 describes a fine web having a relatively dense fine fiber nucleus and fibers or fiber bundles extending outward from the nucleus. can be used as an absorbent body for absorbent articles. This fine web is produced by ripping off or tearing off a raw material sheet such as a nonwoven fabric. substantially do not have

JP 2015-16296 A Japanese Patent Application Laid-Open No. 2002-301105 JP-A-1-156560

An absorbent article, such as a night napkin, which has a pair of rear flaps on both lateral sides of the rear region, when worn, the region sandwiched between the pair of rear flaps curves along the wearer's buttocks. Therefore, it is desired to fit the wearer's skin with good fit, thereby achieving a predetermined leak-proof effect. However, conventional absorbent articles of this type have not sufficiently realized such a desirable state when worn, and there is room for improvement in fit to the buttocks.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an absorbent article that fits well on the buttocks of the wearer and has excellent leakproofness.

The present invention has a vertical direction corresponding to the front-rear direction of the wearer and a horizontal direction perpendicular to the longitudinal direction, and includes an excretion-part facing region arranged to face the wearer's excretory part when worn, and the excretion-part facing region. and a rear region arranged on the rear side in the longitudinal direction of the excretory part facing region, and arranged on the absorber and the skin facing side of the absorber. A pair of rears comprising an absorbent main body comprising a topsheet and members positioned in the rear region and extending laterally outward from both longitudinal side edges of the absorbent main body. and a flap portion, wherein the absorbent body contains water-absorbing fibers and fiber clumps containing fibers having lower water-absorbing properties than the water-absorbing fibers, and a plurality of the fiber clumps are separated from each other. Alternatively, the fiber clumps and the water-absorbent fibers are entangled, and the ratio of the mass content of the fiber clumps to the total mass content of the fiber clumps and the water-absorbent fibers is partially different in the surface direction of the absorbent body. and the absorbent body has, in a region sandwiched between the pair of rear flap parts, a rear fiber lump high content portion having a higher ratio than a portion having the minimum ratio in the absorbent body. It is an article.

The absorbent article of the present invention fits well to the wearer's buttocks and is excellent in leakproofness.

FIG. 1 is a plan view schematically showing the skin-facing surface side (top sheet side) of a sanitary napkin that is one embodiment of the absorbent article of the present invention. FIG. 2 is a schematic cross-sectional view taken along the line II of FIG. 1 (the portion where the front side high-fiber mass content portion exists). FIG. 3 is a schematic cross-sectional view taken along line II-II of FIG. 1 (the portion where the rear high fiber mass content portion exists). FIG. 4 is a schematic cross-sectional view taken along line III-III of FIG. 1 (the site where the erection-inhibiting portion of the posterior region exists). FIG. 5 is a schematic plan view of the skin facing surface side of one embodiment of the absorbent body according to the present invention. FIG. 6 is a schematic perspective view of one example of a fiber mass according to the present invention. FIG. 7(a) is an electron micrograph (observation magnification of 25 times) of an example of a fiber mass according to the present invention, and FIG. 7(b) is a diagram schematically showing the fiber mass in the electron micrograph.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on its preferred embodiments with reference to the drawings. In addition, in the following description of the drawings, the same or similar reference numerals are given to the same or similar parts. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

1 to 4 show a sanitary napkin 1 that is one embodiment of the absorbent article of the present invention. As shown in FIG. 1, the napkin 1 corresponds to the wearer's front-rear direction, and extends from the wearer's abdomen (front) to the back (rear) through the crotch, and a longitudinal direction X perpendicular to this. and an excretory part-facing area M including an excretion part-facing part facing the wearer's excretory part such as the vaginal opening when worn, and an excretory part-facing area M extending in the longitudinal direction X from the excretory part-facing area M. It has a front area F arranged on the front side and a rear area R arranged on the rear side in the longitudinal direction X of the excretory part facing area M. The excretory portion facing portion is located in the center portion of the excretory portion facing region M in the lateral direction Y. As shown in FIG.

The napkin 1 of this embodiment is a so-called night napkin, and is mainly worn at night (when the wearer goes to bed). In general, a nighttime napkin is worn for a longer period of time than a so-called daytime napkin, which is worn mainly during the wearer's activity, and thus absorbs and retains a large amount of excrement such as menstrual blood excreted during the long wearing period. Ability to do so is required. In order to meet such demands, the napkin 1 preferably has a larger area than a typical daytime napkin (a sanitary napkin that does not have a flap portion in the rear region). is preferably 27 cm or more, more preferably 30 cm or more.

As shown in FIG. 1, the napkin 1 has an absorbent main body 5 elongated in the longitudinal direction X, and is located in the rear region R and extends outward in the lateral direction Y from both side edges along the longitudinal direction X of the absorbent main body 5. and a pair of rear flap portions 52, 52 comprising members extending from the rear flap portion 52,52. The absorbent main body 5 of the present embodiment further includes members located in the excretory portion facing region M and extending outward in the lateral direction Y from both side edges along the longitudinal direction X of the absorbent main body 5 . A pair of front flap portions 51, 51 are provided. The front flap portion 51 is a portion called a wing portion or the like in this type of sanitary napkin.

The absorbent main body 5 is a main part of the napkin 1, and includes at least the absorbent body 4 and a liquid-permeable surface sheet 2 disposed on the skin-facing side of the absorbent body 4 and capable of coming into contact with the wearer's skin. Equipped with The absorbent main body 5 of this embodiment further comprises a leak-proof backsheet 3 arranged on the non-skin facing side of the absorbent body 4, as shown in FIG. The absorbent main body 5 is divided into three regions in the longitudinal direction X, ie, a front region F, an excretion-part-facing region M, and a rear region R. As shown in FIG.

As used herein, the term “skin-facing surface” refers to the surface of the absorbent article or its constituent members (for example, the absorbent body 4) that faces the wearer's skin when the absorbent article is worn, i.e. The "non-skin facing surface", which is the side close to the skin, is the side of the absorbent article or its constituent members opposite to the skin side when the absorbent article is worn, that is, the side relatively far from the wearer's skin. It is an aspect that can be It should be noted that the term "when worn" as used herein means a state in which the absorbent article is maintained in a normal and appropriate wearing position, that is, in a correct wearing position of the absorbent article.

As shown in FIG. 1, the napkin 1 of the present embodiment has a central folding line CFL formed when the napkin 1 is folded in the longitudinal direction X, and a first region in front of the longitudinal direction X. and a rear second region. In other words, the center folding line CFL is the boundary between the excretory portion-facing region M and the rear region R. As shown in FIG. The central folding line CFL is formed by folding the napkin 1 in the longitudinal direction X with the top sheet 2 facing inside (the back sheet 3 facing outside) and forming a straight line extending in the transverse direction Y. The center folding line CFL may be formed in the center of the napkin 1 in the longitudinal direction X. Specifically, the center of the napkin 1 in the longitudinal direction X is used as a reference, and the front side in the longitudinal direction X and the It is an area within 10% of the total length of the napkin 1 in the longitudinal direction X on each rear side.

Further, in the napkin 1 of the present embodiment, as shown in FIG. 1, one front folding line FFL is formed in the front region F, and one rear folding line RFL is formed in the rear region R. These folding lines FFL and RFL are also formed by folding the napkin 1 in the longitudinal direction X with the top sheet 2 facing inward, and form straight lines extending in the lateral direction Y, similarly to the central folding line CFL. . The front folding line FFL is generally formed at a position spaced apart from the front end in the longitudinal direction X of the napkin 1 to the rear in the longitudinal direction X by 10 to 30% of the total length in the longitudinal direction X of the napkin 1 . The rear folding line RFL is normally formed at a position spaced from the rear end of the napkin 1 in the longitudinal direction X to the front side in the longitudinal direction X by 10 to 30% of the total length of the napkin 1 in the longitudinal direction X.

Thus, the napkin 1 of this embodiment has a total of three folding lines, the front folding line FFL, the central folding line CFL, and the rear folding line RFL, in order from the front side in the longitudinal direction X, and these folding lines are , when the napkin 1 is folded in the longitudinal direction X and individually packaged. In other words, the individually wrapped napkin 1 is folded in four with three folding lines.

When the absorbent article has a front flap portion (so-called wing portion) like the napkin 1 of the present embodiment, the excretory portion facing region M in the absorbent article of the present invention is defined by the central folding line CFL and the front flap portion. 51 in the longitudinal direction X and the base of the front side. In other words, the excretory portion facing region M has an imaginary straight line extending in the horizontal direction Y through the front base in the vertical direction X of the front flap portion 51 as the front end in the vertical direction X, and the center folding line CFL as the rear end in the vertical direction X. is one continuous area. If one of the pair of front flap portions 51, 51 and the other of the pair of front flap portions 51 and 51 have different positions of the base on the front side in the longitudinal direction X, the base relatively far from the central folding line CFL, that is, the napkin The base relatively closer to the front end of the napkin 1 in the longitudinal direction X (the longitudinal end of the napkin 1 on the front region F side) is used as the boundary between the excretory part facing region M and the peripheral part. In the napkin 1 of this embodiment, as shown in FIG. 1, the pair of front flap portions 51, 51 divides the napkin 1 into two in the horizontal direction Y and is symmetrical with respect to the vertical center line CL extending in the vertical direction X. Therefore, the root of one front flap portion 51 on the front side in the longitudinal direction X and that of the other front flap portion 51 exist at the same position in the longitudinal direction X.

In addition, when the absorbent article does not have the front flap portion 51, the excretory portion facing region M of the absorbent article is the width of the absorbent article that occurs when the absorbent article is folded into an individual packaging form. means the area bounded by the first fold line and the second fold line counted from the longitudinal front edge of the absorbent article. Referring to FIG. 1, the front folding line FFL corresponds to the first folding line and the central folding line CFL corresponds to the second folding line. That is, if the napkin 1 shown in FIG. 1 does not have a pair of front flap portions 51, 51, the excretion portion facing region M has the front folding line FFL as the front end in the longitudinal direction X, and the central folding line CFL. It is one continuous area with the rear end in the vertical direction X. FIG.

As shown in FIGS. 2 to 4, the topsheet 2 covers the entire skin-facing surface of the absorbent body 4, and the backsheet 3 covers the entire non-skin-facing surface of the absorbent body 4. As shown in FIGS. The back sheet 3 extends further outward in the lateral direction Y than the top sheet 2, and forms side flap portions 53 together with side sheets 60, which will be described later. The side flap portions 53 include members (the top sheet 2, the back sheet 3 and the side sheets 60 in this embodiment) extending outward in the lateral direction Y from both side edges 4S, 4S along the longitudinal direction X of the absorbent body 4. It is a portion configured to include the front flap portion 51 and the rear flap portion 52 described above. A plurality of members extending outward from the peripheral edge of the absorber 4 are joined together by a known joining means such as an adhesive, heat sealing, or ultrasonic sealing. The absorbent body 4 and the topsheet 2 and backsheet 3 may be bonded together with an adhesive.

As the top sheet 2 and the back sheet 3, various types of materials conventionally used for this type of absorbent article can be used without particular limitation. As the surface sheet 2, for example, a liquid-permeable single-layer or multi-layer nonwoven fabric can be used, and examples of the nonwoven fabric include carded nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlaced nonwoven fabrics, and needles. A punched nonwoven fabric can be exemplified. The nonwoven fabric forming the surface sheet 2 may be subjected to hydrophilization treatment using a hydrophilizing agent such as a surfactant. The back sheet 3 is a sheet having a leakproof property, that is, a liquid-impermeable (liquid-impermeable property) or a liquid-impermeable (liquid-impermeable property, although not liquid-impermeable). can be used, for example, a moisture-permeable resin film can be used.

In the pair of front flap portions 51, 51, the members (the back sheet 3 and the side sheets 60 in this embodiment) constituting the side flap portions 53 of the excretion portion facing region M are positioned outward in the lateral direction Y from the peripheral portion. It is formed by extending to The front flap part 51 of this embodiment has a substantially trapezoidal shape in which the lower base (longer side than the upper base) is located on the absorbent main body 5 side in plan view as shown in FIG. It exists over substantially the entire length of the region M in the longitudinal direction X. A front flap portion fixing member 54 for fixing the front flap portion 51 to clothing such as shorts is provided on the non-skin facing surface of the front flap portion 51 . In addition, since the front flap portion 51 is folded back to the non-skin facing surface (outer surface) side of the crotch portion of clothing such as shorts, the front flap portion 51, which is the surface on which the front flap portion fixing member 54 is formed, does not touch the skin. The facing surface faces the wearer's skin when in use, and serves as the skin facing surface. The front flap portion fixing member 54 is formed by applying an adhesive, and is covered with a release sheet made of film, nonwoven fabric, paper, or the like before use.

In the pair of rear flap portions 52, 52, the members forming the side flap portions 53 of the rear region R (the back sheet 3 and the side sheets 60 in this embodiment) extend outward in the lateral direction Y from the peripheral portion. formed out of In the plan view as shown in FIG. 1, the rear flap portion 52 of the present embodiment has a front side in the vertical direction X (a portion near the excretion portion facing region M) that extends in the horizontal direction Y from the front side to the rear side in the vertical direction X. The length (width) gradually increases, and the rear end side in the vertical direction X gradually decreases in width from the front side to the rear side in the vertical direction X, and is sandwiched between the front side and the rear side. The intermediate portion has a constant width. Further, the rear flap portion 52 of the present embodiment extends over substantially the entire length of the excretory portion facing region M in the longitudinal direction X, and is formed symmetrically with respect to the longitudinal center line CL, similarly to the front flap portion 51 . A rear flap portion fixing member 55 for fixing the rear flap portion 52 to clothing such as shorts is provided on the non-skin facing surface of the rear flap portion 52 . The rear flap portion 52 is not folded back when it is fixed to the clothes, and the rear flap portion fixing member 55 is attached while the non-skin-facing surface is expanded, that is, the rear flap portion fixing member 55 is extended to the side of the absorbent main body 5 . It is secured to the skin-facing or inner surface of the garment via the . The rear flap portion fixing member 55 is formed by applying an adhesive, and is covered with a release sheet made of film, nonwoven fabric, paper, or the like before use.

As shown in FIGS. 1 to 4, a pair of anti-leakage cuffs 6, 6 are arranged on both sides of the absorbent main body 5 along the longitudinal direction X. As shown in FIGS. The pair of leak-preventing cuffs 6, 6 each includes a sheet for forming a leak-preventing cuff, and includes a base end portion 61 to which the sheet for forming a leak-preventing cuff is fixed to another member, and the leak-preventing cuff. The forming sheet has a standing portion 62 that stands up toward the wearer from the base end portion 61 . In this embodiment, the side sheet 60 described above is the sheet for forming the leakage-preventing cuff.

As shown in FIG. 1, the side sheets 60 (leakage-preventive cuff-forming sheets) are arranged along the sides of the absorbent main body 5 along the longitudinal direction X over substantially the entire length of the absorbent main body 5 in the longitudinal direction X. The side sheet 60 covers the skin-facing surface of the absorbent body 5 , that is, the skin-facing surface of the topsheet 2 . As a result, the pair of anti-leakage cuffs 6, 6 are arranged continuously in the longitudinal direction X from the front area F to the rear area R, respectively. A liquid-impermeable sheet is preferable as the side sheet 60, and for example, a sheet that can be used as the back sheet 3 can be used.

The proximal end portion 61 is a portion that becomes a standing proximal end when the standing portion 62 stands toward the wearer's skin when the napkin 1 is worn. sheet) is a portion adjacent to the standing portion 62 in the lateral direction Y in the portion fixed to "another member", in other words, it is the innermost portion in the lateral direction Y in the fixing portion . In addition, the above-mentioned "other member" is a member other than the side sheet 60 among the constituent members of the napkin 1, and typically, the non-skin facing side of the side sheet 60 is provided so as to be in contact with the side sheet 60. It is an arranged member, and in this embodiment, it is the surface sheet 2 as shown in FIGS.

As described above, the base end portion 61 is a fixing portion between the side sheet 60 (the sheet for forming the leak-proof cuff) and another member, and is typically fixed by a known adhesive such as hot melt, heat sealing, or the like. is formed by the joining means of As shown in FIG. 1, the base end portion 61 of the present embodiment has a straight shape in a plan view, extends in the longitudinal direction X over substantially the entire length of the side seat 60 in the longitudinal direction X, and is shown in FIGS. 2, it is located in the vicinity of the side edge 2S along the longitudinal direction X of the topsheet 2. As shown in FIG.

The standing portion 62 is a portion of the side sheet 60 (leakage-preventive cuff-forming sheet) that is not fixed to other members, and includes at least an inwardly extending portion 620 that extends inward in the lateral direction Y from the base end portion 61 . It is As shown in FIGS. 2 and 3, the standing portion 62 of the present embodiment includes an inner extending portion 620 and an outer extending portion 622 extending outward in the horizontal direction Y via a folded portion 621. ing. In the upright portion 62, the folded portion 621 is closest to the vertical center line CL (see FIG. 1) and is located at the innermost side in the horizontal direction Y. As shown in FIG. The end of the outer extending portion 622 opposite to the folded portion 621 (side edge along the longitudinal direction X) is a free end. When the napkin 1 is worn, the outer extension 622 is positioned relatively close to the wearer's skin, and the inner extension 620 is positioned relatively far from the wearer's skin.

The outer extending portion 622 of the standing portion 62 has elasticity in the longitudinal direction X. As shown in FIG. In this embodiment, as shown in FIGS. 2 and 3, an elastic member 63 having stretchability in the longitudinal direction X is arranged on the side sheet 60 (leakage-preventive cuff forming sheet) that constitutes the outer extending portion 622. With such a configuration, the outer extending portion 622 is provided with stretchability in the longitudinal direction X. As shown in FIG. More specifically, in the present embodiment, the entire leak-proof cuff 6, including the standing-up inhibiting portion 64 and the end fixing portion 65, which will be described later, is formed by folding the side sheets 60 (sheets for forming the leak-proof cuff) into two in the horizontal direction Y. The outer extending portion 622 is a portion extending from the double-folded fold line to the folded portion 621 . An elastic member 63 is fixed in a stretched state between the side sheets 60 , 60 forming a two-layer structure in the outer extending portion 622 of the standing portion 62 . A portion of the side sheet 60 where the fold line is located is a free end of the standing portion 62 . The tip of the side sheet 60 folded in two is joined to the top sheet 2 at the base 61 .

The elastic member 63 of the present embodiment has a thread shape, and is fixed in a stretched state to a portion of the side seat 60 that constitutes the outer extending portion 622 of the upright portion 62 with its longitudinal direction aligned with the longitudinal direction X. The elastic member 63 is preferably filamentous, but may also be a wider band. In addition, in the present embodiment, three elastic members 63 are arranged in each anti-leakage cuff 6, but the number of elastic members 63 in each anti-leakage cuff 6 is not particularly limited, and may be one or more. Further, on the premise that the outer extending portion 622 of the standing portion 62 has elasticity in the longitudinal direction X, the elastic member 63 may not be arranged on the outer extending portion 622. In that case, for example, , the portion of the side sheet 60 that constitutes the outer extending portion 622 itself should be stretchable in the longitudinal direction X. As shown in FIG.

The standing portion 62 is a portion sandwiched between a pair of standing inhibiting portions 64, 64 spaced apart in the vertical direction X. As shown in FIG. In this embodiment, as shown in FIG. 1, a pair of erection inhibiting portions 64 are present at a predetermined interval in the longitudinal direction X. , 6 has a stand-up inhibiting portion 64 .

FIG. 4 shows the erection inhibiting portion 64 of the rear portion R. As shown in FIG. The erection inhibiting portion 64 is a portion where the erecting portion 62 is fixed to another member, and literally inhibits the erecting of the erecting portion 62 . As shown in FIG. 4, the standing-up inhibiting portion 64 of the present embodiment is formed by fixing an inner extending portion 620 and an outer extending portion 622 that constitute the standing portion 62 . More specifically, the inwardly extending portion 620 and the outwardly extending portion 622 are joined together, and the inwardly extending portion 620 is positioned inward of the base end portion 61 in the lateral direction Y so that the top sheet 2 is positioned. , and both extending portions 620 and 622 are integrally fixed to the top sheet 2 . There are no particular restrictions on the fixing means between the two extending portions 620 and 622 and the fixing means between the inner extending portion 620 and the top sheet 2. For example, known adhesives such as hot melt adhesives, heat sealing and the like can be used. fixing means can be used. The standing-up inhibiting portion 64 in the front region F is configured similarly to the standing-up inhibiting portion 64 in the rear region R.

When the napkin 1 is worn, the upright portion 62 of the leak-proof cuff 6 (the portion sandwiched between the pair of upright-inhibiting portions 64, 64) is retracted by the contractile force of the elastic member 63, as shown in FIGS. The end portion 61 is used as the standing base end, and the outer extension portion 622 is used as the free end side, so that the napkin 1 is erected, thereby effectively preventing lateral leakage of excreted fluid such as menstrual blood excreted to the skin-facing surface of the napkin 1 . . In addition, when the standing portion 62 is erected, the contractile force of the elastic member 63 is applied to the napkin 1 so that the central portion of the napkin 1 in the longitudinal direction X protrudes toward the non-skin facing surface side (back sheet 3 side). The whole is curved and deformed into a boat shape, which makes it easier for the napkin 1 to fit the shape of the wearer's body.

In the napkin 1 , as shown in FIG. 1 , the portion of the leak-proof cuff 6 located outside the standing-up inhibiting portion 64 in the longitudinal direction X is fixed to another member by the end fixing portion 65 . In the present embodiment, the "other members" are the topsheet 2 and the backsheet 3 . In addition, as shown in FIG. 1, the end fixing portion 65 of the present embodiment has a wavy or zigzag shape in a plan view, and at least the outer extension portion 622 of the leakage prevention cuff 6 and the vicinity thereof, more specifically, , the portion extending from the base end portion 61 to the outer extending portion 622 of the side sheet 60 (leakage-preventive cuff forming sheet) is fixed to another member. The end fixing portion 65 is formed by a known fixing means such as an adhesive such as hot-melt or heat-sealing, and has an adhesive-applied portion or a heat-sealed portion. , it is harder and more rigid than the surrounding non-forming portion of the end fixing portion 65 . The planar shape of the end fixing portion 65 is not limited to a linear shape as shown in FIG. 1 and can be set arbitrarily. The end fixing portion 65 may be the entire portion located on the other side and inside the base end portion 61 in the lateral direction Y. As shown in FIG.

As shown in FIGS. 2 to 4, the absorbent body 4 of the present embodiment has an absorbent core 40 that has liquid absorption properties and absorbs and retains bodily fluids such as menstrual blood, and an outer surface of the absorbent core 40 that covers the absorbent core 40. and a liquid-permeable core wrap sheet 41. Like the absorbent main body 5 , the absorbent core 40 has a shape elongated in the longitudinal direction X in plan view as shown in FIG. , and the width direction of the absorbent core 40 coincides with the lateral direction Y of the napkin 1 . As shown in FIG. 1, the absorbent body 4 (absorbent core 40) extends over substantially the entire length of the napkin 1 (absorbent main body 5) in the longitudinal direction X, and extends from the front region F to the rear region via the excretory part facing region M. extending over R. The absorbent core 40 and the core wrap sheet 41 may be joined with an adhesive such as a hot-melt adhesive.

The core wrap sheet 41 may be 1) composed of only one sheet, or 2) may be composed of a plurality of sheets. The core wrap sheet 41 of 1) is, for example, one continuous sheet having a width of two to three times the length of the absorbent core 40 in the lateral direction Y, and the absorbent core 40 faces the skin. It covers the entire surface and extends outward in the lateral direction Y from both side edges along the longitudinal direction X of the absorbent core 40, and the extending portion is rolled down below the absorbent core 40 to absorb It covers the entire non-skin facing surface of the core 40 . The core wrap sheet 41 of 2) is, for example, one skin-side core wrap sheet that covers the skin-facing surface of the absorbent core 40, and a skin-side core wrap sheet that is separate from the absorbent core 40. It is composed of two sheets, one of which is a non-skin side core wrap sheet covering the non-skin facing surface.

The absorbent core 40 is mainly composed of a core-forming material, and typically composed of only the core-forming material. The core-forming material includes at least water-absorbing fibers 12F and fiber masses 11 containing fibers 11F. The constituent fibers 11F of the fiber mass 11 are typically synthetic fibers. The absorbent core 40 shown in FIG. 2 further contains the particulate water-absorbing polymer 13 in addition to the fiber mass 11 and the water-absorbing fibers 12F.

The absorbent core 40 can be said to be substantially the absorbent body 4 itself, and unless otherwise specified, the following description of the absorbent core 40 is appropriately applied as the description of the absorbent body according to the present invention. The absorbent body according to the present invention includes a form composed only of an absorbent core without a core wrap sheet, and in such a form, the absorbent body and the absorbent core have the same meaning. .

The material (core-forming material) constituting the absorbent core 40 includes at least water-absorbent fibers 12F and fiber masses 11 containing fibers 11F, as shown in FIGS. In the absorbent core 40 of this embodiment, the water absorbent polymer 13 is further included as a core forming material. The constituent fibers 11F of the fiber mass 11 are fibers having lower water absorption (weak water absorption fibers) than the water absorbent fibers 12F.

As used herein, the term "fiber mass" refers to a fiber aggregate in which a plurality of fibers are bundled together. The fiber mass used in the present invention may be a fiber aggregate of a fixed shape, such as a sheet piece obtained by cutting a synthetic fiber sheet having a certain size with a cutter or the like, regardless of its manufacturing method, or It may also be an amorphous fiber assembly produced by pulverizing, ripping off, or tearing off a nonwoven fabric mainly composed of synthetic fibers, such as the nonwoven fabric pieces disclosed in the above-mentioned patent documents. In the present invention, the absorbent core may i) contain only fixed-shaped fiber aggregates as the fiber mass, ii) may contain only irregular-shaped fiber aggregates as the fiber mass, or iii) may contain only the amorphous fiber mass as the fiber mass. Although a form in which fixed-shaped fiber aggregates and irregular-shaped fiber aggregates are mixed may be used, the above-described form i) is preferably used. In the irregularly shaped fiber assembly, since the constituent fibers are randomly oriented, the surface is rough such that the fibers protrude from here and there on the surface. There is a risk of entanglement, and as a result, the degree of freedom of movement of each fiber assembly is restricted, resulting in reduced flexibility. The fiber clump 11 of this embodiment is a fixed-shaped fiber aggregate as described later.

As described above, the fiber mass 11 is a fiber assembly in which a plurality of fibers 11F are aggregated and integrated, and a plurality of the fiber masses 11 are present in the absorbent core 40 while maintaining their shape. The fiber mass 11 mainly contributes to improvement of the flexibility, cushioning properties, compression recovery properties, and shape retention properties of the absorbent core 40 due to the form of the fiber assembly.

A plurality of water-absorbent fibers 12F are present in the absorbent core 40, and although the plurality of water-absorbent fibers 12F can be entangled with each other, they are not aggregated like the constituent fibers 11F of the fiber mass 11, and are individually independent. preferably present in The water absorbent fibers 12F mainly contribute to improving the liquid absorbency of the absorbent core 40 and also contributes to improving the shape retention of the absorbent core 40 .

As the water-absorbing fibers 12F, water-absorbing fibers conventionally used as a material for forming the absorbent body of this type of absorbent article can be used. Examples of water-absorbent fibers include wood pulp such as softwood pulp and hardwood pulp, natural fibers such as non-wood pulp such as cotton pulp and hemp pulp; modified pulp such as cationized pulp and mercerized pulp. These 1 type can be used individually or in mixture of 2 or more types. Considering that the main role of the absorbent fibers 12F is to improve the liquid absorbency of the absorbent body 4, cellulosic fibers are preferable as the absorbent fibers 12F.

A plurality of water-absorbing polymers 13 are present in the absorbent core 40 as small pieces of water-absorbing polymer, and mainly contribute to the improvement of the liquid absorbency in the absorbent core 40 . The shape of the pieces of the water-absorbent polymer 13 is not particularly limited, and may be, for example, spherical, massive, bale-shaped, fibrous, or irregular. The average particle size of the water absorbing polymer 13 is preferably 10 μm or more, more preferably 100 μm or more, and preferably 1000 μm or less, more preferably 800 μm or less. As the water absorbing polymer 13, generally, a polymer or copolymer of acrylic acid or an alkali metal salt of acrylic acid can be used. Examples thereof include polyacrylic acid and its salts and polymethacrylic acid and its salts. Specifically, acrylic acid polymers such as Aqualic CA and Aqualic CAW (both manufactured by Nippon Shokubai Co., Ltd.) Partial sodium salts are included.

In the absorbent core 40, not only are the plurality of fiber clumps 11 and the water absorbent fibers 12F mixed together, but also the fiber clumps 11 are entangled with each other or the fiber clumps 11 and the water absorbent fibers 12F are entangled. That is, in the absorbent core 40, a plurality of fiber lumps 11 are combined by entanglement with constituent fibers (fibers 11F, 12F) in the absorbent core 40 to form one fiber lump continuum. Further, the plurality of fiber clumps 11 may be entangled with each other, and the fiber clumps 11 and the absorbent fibers 12F may be entangled and bonded. Furthermore, usually, a plurality of water absorbent fibers 12F are also entangled with each other. At least some of the plurality of fiber lumps 11 contained in the absorbent core 40 are entangled with other fiber lumps 11 or water absorbent fibers 12F. In the absorbent core 40, all of the plurality of fiber lumps 11 contained therein may be entangled with each other to form one fiber lump continuum. It is possible that they are mixed in the state of combination.

In the absorbent core 40, in addition to containing the fiber clumps 11 capable of increasing the flexibility of the absorbent core 40, the fiber clumps 11 are entangled with each other or between the fiber clumps 11 and the water absorbent fibers 12F. Since the absorbent core 40 is bonded, the absorbent core 40 is more excellent in responsiveness to external force, and is excellent in flexibility, cushioning property, and compression recovery property. The absorbent core 40 deforms flexibly against external forces received from various directions when the napkin 1 is worn (for example, the body pressure of the wearer of the napkin 1), and the napkin 1 can be brought into close contact with the wearer's body with good fit. . Such excellent deformation-recovery characteristics of the absorbent core 40 can be exhibited not only when the absorbent core 40 is compressed but also when twisted. That is, since the absorbent core 40 incorporated in the napkin 1 is sandwiched between the thighs of the wearer when the napkin 1 is worn, it is Movement of the thighs may cause twisting around a virtual axis of rotation extending in the longitudinal direction X. The napkin 1 can be easily deformed and recovered from an external force that promotes twisting from the body, and therefore, it is difficult to twist, and the napkin 1 can be given a high fit to the wearer's body.

In the absorbent core 40, the fiber lumps 11 or the fiber lumps 11 and the water-absorbing fibers 12F are entangled. be done.
Form A: A form in which the fiber clumps 11 and the like are bonded by entanglement of the constituent fibers 11F of the fiber clumps 11 rather than fusion bonding.
Mode B: In the natural state of the absorbent core 40 (the state in which no external force is applied), the fiber clumps 11 and the like are not bonded together, but in the state in which the absorbent core 40 is subjected to an external force, the fiber clumps 11 and the like are bonded together. A configuration in which the constituent fibers 11F can be bound by entanglement with each other. Here, "a state in which an external force is applied to the absorbent core 40" means, for example, that the absorbent core 40 has It is in a state where deformation force is applied.

As described above, in the absorbent core 40, the fiber clumps 11 are connected to other fiber clumps 11 or the water-absorbing fibers 12F by entanglement, ie, "entangling", as in the form A. Like B, it also exists in a state where it can be entangled with other fiber clumps 11 or water absorbent fibers 12F. Such binding by entangling the fibers is one of the important points for more effectively exhibiting the function and effect of the absorbent core 40 described above. In particular, the absorbent core 40 preferably has form A of "entanglement" in terms of shape retention. Bonding by fiber entanglement does not have an adhesive component or fusion, and is made only by entanglement of fibers. The degree of freedom of movement of the fiber 12F) is high, so that its individual elements can move within a range that maintains their integrity as an assembly composed of them. In this way, the absorbent core 40 is deformed when receiving an external force because the plurality of fiber clumps 11 contained therein or the fiber clumps 11 and the absorbent fibers 12F are relatively loosely connected. It has a gentle shape retention that is possible, and has a high level of shape retention, cushioning property, compression recovery property, and the like. The napkin 1 having such a high-quality absorbent core 40 fits tightly to the wearer's body and is comfortable to wear.

It is not necessary that all of the bindings via the fiber lumps 11 in the absorbent core 40 are "entangled", and a part of the absorbent core 40 includes other bindings other than entangling, such as bonding with an adhesive. may be However, for example, the absorbent core 40 or the absorbent body 4 including the same may be subjected to compression processing such as embossing so that the skin-facing surface 45 and/or the non-skin-facing surface 46 of the absorbent core 40 is provided with leak-proof grooves. (for example, a recessed portion 7 to be described later) is formed, the fiber mass 11 or the fiber mass 11 and the water-absorbing fibers 12F are fused in the portion of the absorbent core 40 that overlaps the recessed portion in a plan view. However, at least one of the bonding between the fiber lumps 11 and the bonding between the fiber lumps 11 and the absorbent fibers 12F, Preferably, both of them are made only by "entanglement of fibers".

From the viewpoint of more reliably exerting the action and effect of the absorbent core 40 described above, the form A, "the fiber lumps 11 bound by entangling" and the form B, "the fiber lumps 11 in a state where they can be entangled" are used. is preferably half or more, more preferably 70% or more, still more preferably 80% or more of the total number of fiber lumps 11 in the absorbent core 40 .
From a similar point of view, the number of fiber lumps 11 having "entanglement" of form A is 70% or more, particularly 80% or more of the total number of fiber lumps 11 having bonding portions with other fiber lumps 11 or water-absorbent fibers 12F. Preferably.

The napkin 1 is characterized not only by the absorbent core 40 containing the fibrous masses 11 but also by the arrangement of the fibrous masses 11 in the absorbent core 40 . That is, the fiber clumps 11 are not uniformly distributed over the entire absorbent core 40, and in the plane direction (the direction orthogonal to the thickness direction) of the absorbent core 40 (absorbent body 4), "the fiber clumps 11 and the water absorbent The ratio of the contained mass of the fiber lumps 11 to the total contained mass of the fibers 12F" (hereinafter also referred to as the "fiber lump occupancy ratio") is partially different.

The fiber clump occupancy rate is obtained by measuring the content of each of the fiber clumps 11 and the water-absorbent fibers 12F existing in the predetermined measurement target portion of the absorbent core 40 by mass, and then measuring the fiber clump occupancy rate. 11 is divided by the sum of the masses contained in the water-absorbing fibers 12F and the fiber lumps 11, and expressed as a percentage of 100. That is, fiber lump occupation ratio (% by mass)={mass content of fiber lumps 11/(mass content of water-absorbing fibers 12F+mass content of fiber lumps 11)}×100.

As shown in FIG. 1, the absorbent core 40 (absorbent body 4) has an absorbent core in a region sandwiched between a pair of rear flap portions 52, 52 (hereinafter also referred to as a "rear flap portion existing region"). It has a rear side high fiber lump content portion 42 having a higher fiber lump occupation ratio than the portion having the minimum fiber lump occupation ratio in 40 (hereinafter, also referred to as "minimum fiber lump occupation ratio portion"). In other words, the rear high fiber mass content portion 42 exists within a range overlapping the pair of rear flap portions 52, 52 in the longitudinal direction X. As shown in FIG. The rear high fiber mass content portion 42 is a partial area of the absorbent core 40 in plan view, and the entirety of the partial thickness direction is the rear high fiber mass content portion 42 .

The rear flap existing region is a region divided by the front root and the rear root of the rear flap 52 in the longitudinal direction X. As shown in FIG. That is, the rear flap portion existing region has an imaginary straight line extending in the horizontal direction Y through the base of the front side in the vertical direction X of the rear flap portion 52 as the front end in the vertical direction X, and the rear flap portion 52 in the vertical direction X. It is one continuous area in which an imaginary straight line extending in the horizontal direction Y through the base of the side is the rear end in the vertical direction X. If one of the pair of rear flap portions 52, 52 and the other of the pair of rear flap portions 52, 52 are different in the position of the base on the front side or the rear side in the longitudinal direction X, the front end of the napkin 1 in the longitudinal direction X (the front region of the napkin 1) The rear flap part existing region. In the napkin 1 of the present embodiment, as described above, the pair of rear flap portions 52, 52 are formed symmetrically with respect to the longitudinal center line CL. Therefore, one rear flap portion 52 and the other rear flap portion 52, the position of the root on the front side in the vertical direction X and the position of the root on the rear side are the same. Further, in the napkin 1 of the present embodiment, the entire rear area R is the rear flap existing area. Further, the minimum fiber mass occupation ratio portion is a portion where the fiber mass occupation ratio is minimum in the entire surface direction of the absorbent core 40 (absorbent body 4), and does not always exist in the rear flap portion existence region. , may be interspersed in multiple locations of the absorbent core 40 .

In the present embodiment, as shown in FIG. 1, the rear side fiber lump high content portion 42 exists in a part of the rear flap portion existing region in the longitudinal direction X, specifically in the central portion in the longitudinal direction X. However, in the horizontal direction Y, it exists over the entire length (entire width) of the absorbent core 40 in the horizontal direction Y. As shown in FIG. Further, in the present embodiment, all portions of the absorbent core 40 other than the rear high fiber mass content portion 42 and the front high fiber mass content portion 43 to be described later are the minimum fiber mass occupancy portion.

A rear side fiber lump high content portion containing a relatively large amount of fiber lumps 11 excellent in flexibility, cushioning properties, etc. in the rear flap portion existing region (region sandwiched between the pair of rear flap portions 52, 52) of the napkin 1. Due to the presence of 42, when the napkin 1 is attached to the wearer's crotch, the rear region R including the rear flap portion existing region is applied to the wearer's buttocks and curved along the outer shape of the buttocks. Sometimes, the posterior high fiber mass content portion 42 is flexibly deformed along the buttock groove (gluteal cleft), so that the fit to the wearer's buttocks is improved, and leakage in the posterior region R is effective. is prevented.

From the viewpoint of ensuring that the effects of the rear high fiber mass content portion 42 are exhibited more reliably, the fiber mass occupation ratio of the rear high fiber mass content portion 42 is preferably 30% by mass or more, more preferably. is 35% by mass or more, and 100% by mass, that is, the rear side fiber mass high content portion 42 does not need to contain the water absorbent fibers 12F at all instead of containing the fiber mass 11 .

On the premise that the fiber mass occupancy of the minimum fiber mass occupancy portion is smaller than the fiber mass occupancy of the rear high fiber mass content portion 42 and the front high fiber mass content portion 43, which will be described later, is preferably 25% by mass. Below, more preferably 20% by mass or less. The portion having the minimum fiber lump occupancy rate may have a fiber lump occupancy rate of 0% by mass, that is, may not contain the fiber lump 11 at all. In the present embodiment, all portions of the absorbent core 40 other than the rear high fiber mass content portion 42 and the front high fiber mass content portion 43 to be described later are the minimum fiber mass occupancy portion, and the fiber mass content is minimized. The minimum occupancy portion does not substantially contain the fiber mass 11, and the minimum fiber mass occupancy portion is mainly composed of the absorbent fibers 12F (see FIG. 4).

From the same point of view, the length L42 (see FIG. 1) in the longitudinal direction X of the rear high fiber mass content portion 42 is preferably 20% or more and 50% or less of the length in the longitudinal direction X of the rear flap portion existing region. , more preferably 25% or more and 45% or less. In addition, the length (width) W42 (see FIG. 1) in the lateral direction Y of the rear fiber lump high content portion 42 is preferably 20% or more or more than the length of the lateral direction Y of the absorbent core 30. It is preferably 40% or more, and may be 100%, that is, the rear high fiber mass content portion 42 may extend over the entire width of the absorbent core 40 as shown in FIG.

In addition, when there are a plurality of rear fiber mass high content portions 42 as shown in FIG. When the length is divided into three equal parts, the length of the rear high fiber mass content portion 42 existing in the two rear regions is the range described above in relation to the length of the rear flap portion existing region in the longitudinal direction X. If it is In the form shown in FIG. 5, two rear high fiber mass content portions 42 are intermittently arranged in the longitudinal direction X in the rear flap portion existing region, and one of the two portions near the excretory portion facing region M is located. Where the rear high fiber mass content portion 42 is connected to the front high fiber mass content portion 43, the length of the other rear high fiber mass content portion 42 that is not connected to the front high fiber mass content portion 43 is not connected to the front high fiber mass content portion 43. It is sufficient that the length in the direction X is within the range described above.

The position in the longitudinal direction X of the rear high fiber mass content portion 42 is not particularly limited as long as it is within the region where the rear flap portion exists. It is preferable that at least a part of the rear side high fiber mass content portion 42 exists on the rear side. As a result, the function and effect of the above-described rear fiber lump high content portion 42 can be exhibited more reliably. The napkin 1 shown in FIG. 1 has such a structure.

From the same point of view, it is preferable that at least a part of the rear high fiber mass content portion 42 overlaps the rear flap fixing member 55 in the longitudinal direction X. As shown in FIG. The napkin 1 shown in FIG. 1 has such a structure.

In the rear high fiber lump content portion 42, the fiber lumps 11 may be distributed in any way, or may be uniformly distributed throughout the rear high fiber lump content portion 42. It may be unevenly distributed in a part of the thickness direction of 42 . As a specific example of the latter, a configuration in which the fiber lumps 11 are unevenly distributed on the skin-facing surface 45 side or the non-skin-facing surface 46 side of the rear high fiber lump content portion 42 (absorbent core 40) can be exemplified. In this specification, the “skin-facing surface side” refers to the thickness of the absorbent core 40 in the region (for example, the front region F, the excretory region-facing region M, the rear region R, and the rear fiber lump high content portion 42). It is a portion closer to the skin-facing surface 45 when bisected in the direction, and the "non-skin-facing surface side" is a portion closer to the non-skin-facing surface 46 in such a case.

It is preferable that the non-skin facing surface 46 side of the rear fiber lump high content portion 42 has a higher fiber lump occupancy than the skin facing surface 45 side. In the present embodiment, such a magnitude relationship of "fibrous mass occupancy on the non-skin-facing surface 46 side>fibrous mass occupancy on the skin-facing surface 45 side" holds, and as shown in FIG. In the containing portion 42, the fiber clumps 11 are unevenly distributed on the non-skin-facing surface 46 side, and the core-forming materials other than the fiber clumps 11 (in this embodiment, the water-absorbing fibers 12F and the water-absorbing polymer 13) are on the skin-facing surface 45 side. unevenly distributed.

By establishing the size relationship in the rear high fiber mass content portion 42, the effect of mainly the fiber mass 11, such as the effect of improving flexibility and cushioning properties, is enhanced, and the rear high fiber mass content portion 42 is enhanced. Together with the action and effect of being present in the rear flap part existing region, the fit to the buttocks of the wearer and the leakproofness can be further improved. Further, in this case, the mass (basis weight) per unit area of the water-absorbing fibers 12F can be larger on the skin-facing surface 45 side of the rear high fiber mass content portion 42 than on the non-skin-facing surface 46 side. A relatively large amount of water-absorbing fibers 12F having excellent water-absorbing properties are contained on the side of the skin-facing surface 45, which is the portion of the napkin 1 that first receives bodily fluid excreted by the wearer of the napkin 1 in the rear fiber lump high-content portion 42. As a result, the liquid drawing power (capillary force) and liquid absorbability of this portion are improved, and as a result, the leakproofness is improved. Therefore, in the rear side fiber mass high content portion 42, the size relationship of "fiber mass occupancy on the non-skin facing surface 46 side > fiber mass occupancy on the skin facing surface 45 side" is established, so that the napkin 1 can be worn. It is possible to further improve the possibility that the fitting to the buttocks of a person will be good and the leakproof property will be excellent.

On the premise that the fiber mass occupancy on the non-skin facing surface 46 side of the rear high fiber mass content portion 42 is higher than that on the skin facing surface 45 side located on the opposite side in the thickness direction, it is preferably 50% by mass. More preferably, it is 90% by mass or more, and may be 100% by mass. That is, the non-skin-facing surface 46 side of the rear fiber lump high content portion 42 does not need to contain the absorbent fibers 12F at all instead of containing the fiber lumps 11 .
On the premise that the fiber mass occupancy on the skin facing surface 45 side of the rear high fiber mass content portion 42 is lower than that on the non-skin facing surface 46 side located on the opposite side in the thickness direction, it is preferably 50% by mass. Below, it is more preferably 10% by mass or less, and may be 0% by mass. That is, the non-skin facing surface 46 side of the rear fiber mass high content portion 42 may not contain the fiber mass 11 at all instead of containing the water absorbent fibers 12F.

On the premise that the basis weight of the fiber lumps 11 on the non-skin facing surface 46 side of the rear high fiber lump content portion 42 is larger than that on the skin facing surface 45 side, it is preferably 32 g/m ² or more, more preferably 80 g/m ² or more, preferably 640 g/m ² or less, more preferably 480 g/m ² or less.
On the premise that the basis weight of the fiber lumps 11 on the skin facing surface 45 side of the rear high fiber lump content portion 42 is smaller than that on the non-skin facing surface 46 side, it is preferably 320 g/m 2 or less, more preferably 320 g/m ² or less. 240 g/m ² or less, and may be 0 g/m ² .

In the rear-side fiber mass high content portion 42, when the above-described magnitude relationship of "fiber mass occupancy on the non-skin facing surface 46 side>fiber mass occupancy on the skin facing surface 45 side" holds, 1) the skin facing surface 45 The fiber mass occupancy may be constant without changing in the thickness direction on each side and the non-skin-facing surface 46 side, or 2) the fiber mass occupancy may increase from the skin-facing surface 45 side toward the non-skin-facing surface 46 side. may be gradually increased. In the above-mentioned form 2), in the thickness direction of the rear high fiber mass content portion 42 (absorbent core 40), the fiber mass 11 does not exist in the skin facing surface 45 and its vicinity, or the absorbency of the longitudinal central region M is reduced. The core 40 has the lowest fiber mass occupation ratio, and the fiber mass 11 exists at the rear high fiber mass content portion 42 at the highest fiber mass occupation ratio on the non-skin facing surface 46 and its vicinity.

As an advantage peculiar to the above-described form 1), the skin-facing surface 45 side and the non-skin-facing surface 46 side of the rear fiber lump high content portion 42 can be easily designed to have independent functions. In addition, as an advantage peculiar to the above-mentioned form 2), since the mixing ratio of the fiber lumps 11 and the water-absorbing fibers 12F changes gently in the thickness direction of the rear side fiber lump high content portion 42, the rear side fiber lump high content content Even when an external force is applied to the portion 42, the entangled state intervening the fiber lumps 11 is easily maintained in the thickness direction, and the flexibility, cushioning properties, etc. of the rear side high fiber lump content portion 42 are maintained well during use. There are easy points.

Regarding the minimum fiber mass occupancy portion (the portion where the fiber mass occupancy is minimum in the absorbent core 40), when the fiber mass 11 exists in the minimum fiber mass occupancy portion, the distribution thereof is not particularly limited. , it may be uniformly distributed over the entire portion of the minimum fiber mass occupancy, or unevenly distributed in a part of the portion of the minimum fiber mass occupancy in the thickness direction, and in the latter case, 1) or 2) above. can take the form of

In the napkin 1 of the present embodiment, as shown in FIGS. 1 to 4, the surface sheet 2 and the absorbent body 4 (the skin-side core wrap sheet and the absorbent core 40) are integrally recessed on the non-skin facing surface of the absorbent body 4 (on the side of the non-skin facing surface 46 of the absorbent core 40). The recesses 7 extend in the vertical direction X (outer vertical recess 7X1, inner vertical recess 7X2) and in the horizontal direction Y (outer horizontal recess 7Y1, inner horizontal recess 7Y2). including. The recessed portion 7 does not penetrate the absorbent body 4 (absorbent core 40), has an opening on the skin-facing surface of the topsheet 2, and has a bottom on the side opposite to the opening. The concave portion 7 formed on the skin-facing surface of the napkin 1 has a function of inhibiting movement of body fluid such as menstrual blood in the planar direction. Hereinafter, various recessed portions such as the outer vertical recessed portion 7X1 are collectively referred to as the "recessed portion 7".

In the above-mentioned "existing in a position where the recessed portion 7 overlaps the rear high fiber mass content portion 42 in the longitudinal direction X", the recessed portion 7 and the rear high fiber mass content portion 42 overlap in plan view. and non-overlapping forms. The former is typically the case, and the former is employed in this embodiment as well. As a specific example of the latter form, the rear high fiber mass content portion 42 is present in the lateral direction Y central portion of the rear flap portion existence region (the region sandwiched between the pair of rear flap portions 52, 52), and A pair of recessed portions 7 (outer vertical recessed portions 7X1) extending in the longitudinal direction X can be exemplified as a configuration in which the rear side fiber mass high content portion 42 is present on both sides in the lateral direction Y. As shown in FIG.

Further, the above-mentioned "extending recesses 7" includes A) a mode in which the recesses 7 extend in a continuous line in the vertical direction X (horizontal direction Y), and B) a mode in which a plurality of recesses 7 extend in the vertical direction. A configuration in which a plurality of concave portions 7 are intermittently arranged in X (horizontal direction Y) and appear to extend in the longitudinal direction X (horizontal direction Y) as a whole is also included. In the latter case, the distance in the longitudinal direction X (lateral direction Y) between the two recesses 7 closest to each other in the longitudinal direction X (lateral direction Y) is preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 5 mm or less.

A pair of outer vertical recessed portions 7X1 extend in the longitudinal direction X and are spaced apart in the lateral direction Y by a predetermined distance at least at positions overlapping the rear high fiber mass content portion 42 in the longitudinal direction X. As shown in FIG. More specifically, as shown in FIG. 1, the pair of outer vertical recessed portions 7X1, 7X1 respectively overlap the rear high fiber mass content portion 42 in plan view, and extend over the entire length of the rear region R in the longitudinal direction X. It extends further to the excretory part facing region M and the front region F, and forms a continuous line as a whole.

A pair of outer horizontal recessed portions 7Y1 extend in the horizontal direction Y and are present in a pair in the vertical direction X with a predetermined interval therebetween. More specifically, as shown in FIG. 1, one of the pair of outer lateral recesses 7Y1 and 7Y1 is located in the front region F and the other is located in the rear region R, Each of them has a U-shape or an arc-shape that protrudes outward in the vertical direction X when viewed from above, and the top of the U-shape or arc-shape is positioned at the center of the napkin 1 in the horizontal direction Y. As shown in FIG.

The outer vertical recessed portion 7X1 and the outer lateral recessed portion 7Y1 are connected at their lengthwise ends, and the outer recessed portion as a whole has a closed annular shape, more specifically, a substantially elongated elliptical shape in plan view. is making The area surrounded by the pair of outer vertical recesses 7X1, 7X1 in the excretory part-facing area M is located in the central part of the excretory part-facing area M and includes the excretory part-facing part.

The inner vertical recessed portion 7X2 (the recessed portion 7 extending in the vertical direction X different from the outer vertical recessed portion 7X1) is a pair of outer vertical recesses at positions overlapping at least the rear high fiber lump content portion 42 in the vertical direction X. In the area sandwiched between the concave portions 7X1, 7X1, a pair of them extend in the longitudinal direction X and are present in the lateral direction Y at a predetermined interval. More specifically, as shown in FIG. 1, the pair of inner vertical recessed portions 7X2 and 7X2 are respectively connected to the rear fiber lump high content portion 42 in the region sandwiched between the pair of outer vertical recessed portions 7X1 and 7X1. They overlap in plan view, extend forward in the longitudinal direction X from the rear fiber lump high content portion 42, and extend to the boundary (central folding line CFL) between the rear region R and the excretory portion facing region M or the vicinity thereof. and forms a continuous line as a whole.

As shown in FIG. 1, the inner horizontal recessed portion 7Y2 is located in the rear fiber lump high content portion 42 in the region sandwiched between the pair of outer vertical recessed portions 7X1, 7X1, and is positioned in the longitudinal direction of the napkin 1 in plan view. A convex U-shape or arcuate shape is formed toward the rear end of the X, and the top of the U-shape or arcuate shape is positioned in the center of the napkin 1 in the horizontal direction Y.

The inner vertical recessed portion 7X2 and the inner horizontal recessed portion 7Y2 are connected at their longitudinal ends, and the entire inner recessed portion protrudes toward the rear end in the vertical direction X of the napkin 1 in plan view. , and the top of the U-shape or arc is located in the center of the napkin 1 in the lateral direction Y. As shown in FIG.

The concave portion 7 is formed by compressing the absorbent main body 5 from the side of the surface facing the skin (the side of the topsheet 2) from the napkin 1, and is called a "compression portion" from the forming method. can be said. The recessed portion 7 which is the compressed portion has a higher density than the periphery of the recessed portion 7 in the absorbent body 4 . That is, the absorbent main body 5 has a high-density portion corresponding to the recessed portion 7 and a low-density portion in which the recessed portion 7 is not formed, thereby producing a density difference in the planar direction.

The pressing process for forming the concave portion 7 is a method involving melting of the core-forming material contained in the absorbent body 4 (absorbent core 40), particularly melting of thermoplastic fibers preferably used as the constituent fibers 11F of the fiber mass 11. may be used, or a method that does not involve melting of the core-forming material may be used. Specific examples of the pressing process involving melting of the core-forming material include known embossing processes such as embossing processes involving heat and ultrasonic embossing. The top sheet 2 and the core wrap sheet 41 (skin-side core wrap sheet) are formed at the bottom of the recessed portion 7 formed by pressing with melting of the core forming material, that is, at the portion overlapping with the recessed portion 7 which is a space in plan view. and the absorbent core 40 may be heat-sealed and integrated.

The rear fiber lump high content portion 42 contains a relatively large amount of fiber lumps 11, so that shape retention and softness are improved compared to other portions of the absorbent core 40 (the minimum fiber lump occupancy portion). A pair of recessed portions 7 (outer vertical recessed portions 7X1) extending in the longitudinal direction X are provided at positions overlapping the rear high fiber mass content portion 42 in the longitudinal direction X. Such properties can be further improved by the presence of Such a rear fiber lump high content portion 42 is hard to lose its shape even when subjected to an external force, deforms with good responsiveness to the external force, and can quickly restore itself when the external force is released. In particular, if the recessed portion 7 (the outer vertical recessed portion 7X1) is formed by pressing with melting of the constituent fibers 11F of the fiber mass 11, the fiber mass existing at a position overlapping the recessed portion 7 in plan view. Since the fibers 11 can be fused with other surrounding fiber masses 11 or water-absorbing fibers 12F, shape retention and the like can be further improved.

In addition, in the napkin 1, the density difference occurs in the surface direction due to the fact that the relatively high density recessed portion 7 and the relatively low density low density portion coexist in the surface direction. The difference in density makes it easier for body fluids to diffuse in the plane direction. That is, the napkin 1 can quickly diffuse the bodily fluid excreted by the wearer in the surface direction, and therefore effectively utilizes the absorption performance inherent in the absorbent core 40 to exhibit high liquid leakage prevention. can. Especially in the napkin 1, as shown in FIG. 1, the concave portion 7 exists not only in the rear high fiber mass content portion 42 but also in the front region F to the rear region R, so that the shape retention of the entire napkin 1 and Liquid diffusibility and the like in the surface direction are enhanced.

From the viewpoint of more reliably exhibiting the effects of the rear high fiber mass content portion 42 (improved fit to the wearer's buttocks and leakproofness, etc.), the rear high fiber mass content portion 42 is provided. The region sandwiched between the pair of outer vertical recesses 7X1 and 7X1 (hereinafter also referred to as the “first laterally inner region”) at the position overlapping in the longitudinal direction X is outside the lateral direction Y of the region It is preferable that the fiber clump occupancy is larger than that of the recessed portion 7X1 and its laterally Y outer side (hereinafter also referred to as "first laterally outer region"). The ratio of the fiber clump occupancy ratio between the first laterally outer region and the first laterally inner region is the former (first laterally outer region) / the latter (first laterally inner area) is preferably 0.2 or more and less than 1.0, more preferably 0.3 or more and 0.8 or less. In addition, the above-mentioned magnitude relationship "fibrous mass occupation rate of first laterally inner region>fibrous mass occupancy of first laterally outer region" It is applied to a position that does not overlap in the vertical direction X with the inner vertical recessed portion 7X2 (the recessed portion 7 extending in the vertical direction X different from the outer vertical recessed portion 7X1).

In addition, the same point of view and the effect of the presence of a pair of recessed portions 7 (outer vertical recessed portions 7X1) extending in the vertical direction X at positions overlapping the rear high-fiber mass content portion 42 in the vertical direction X. From the viewpoint of further ensuring the (effect of improving shape retention, etc.), a pair of inner vertical recesses 7X2 (outer vertical recesses The region sandwiched between the concave portions 7 extending in the vertical direction X, which is different from the portion 7X1 (hereinafter also referred to as the “second laterally inner region”) is the laterally Y outer side of the region. (That is, the concave portion 7X2 and its outer side in the lateral direction Y. Hereinafter, it is also referred to as a "second laterally outer region."). The ratio of the fiber clump occupancy ratio between the second laterally outer region and the second laterally inner region is the former (second laterally outer region) / the latter (second laterally inner area) is preferably 0.2 or more and less than 1.0, more preferably 0.3 or more and 0.8 or less.

The width of the recessed portion 7 (the length in the direction orthogonal to the length direction of the recessed portion) is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.5 mm or more, and preferably 10 mm or less, and more preferably. is 5 mm or less. Moreover, the depth of the recessed portion 7 may be constant over the entire length thereof, or may be partially different. In addition, the pattern (shape and arrangement in a plan view) of the recessed portions 7 is not particularly limited. A pattern in which a plurality of recessed portions 7 having a predetermined shape in plan view are intermittently arranged in one direction may be used. shape and so on.

In the absorbent core 40 (absorbent body 4) of the present embodiment, as shown in FIGS. It has a high fiber lump content portion 43 on the front side, which has a higher fiber lump occupancy than the minimum portion). The front high fiber mass content portion 43 is a partial area of the absorbent core 40 in plan view, and the entirety of the partial thickness direction is the front high fiber mass content portion 43 . In the present embodiment, as shown in FIG. 1, the front side fiber lump high content portion 43 is present in the vertical direction X over substantially the entire length of the excretion portion facing region M in the vertical direction X, and in the horizontal direction Y is absorbent. It exists over the entire length (entire width) of the magnetic core 40 in the lateral direction Y.

Since the excretion facing region M is usually sandwiched between the thighs of the wearer when the napkin 1 is worn, it is a virtual It is easy to be twisted around the rotation axis, and twisting is likely to occur. The presence of the front side fiber lump high content portion 43 containing a relatively large amount of fiber lumps 11 excellent in shape retention, flexibility, cushioning, etc. in the excretory part facing region M, which is susceptible to external force, allows the napkin 1 This effectively prevents the absorbent body 4 from being twisted when worn, further improving fit and cushioning properties, and further improving leakproofness.

From the viewpoint of ensuring the effects of the front high fiber mass content portion 43, the fiber mass occupation ratio of the front high fiber mass content portion 43 is preferably 30% by mass or more, more preferably 35% by mass. 100% by mass or more, that is, the front side fiber mass high content portion 43 does not need to contain the fiber mass 11 but the water absorbent fibers 12F at all. Further, the fiber lump occupancy rate may be the same or different between the rear high fiber lump content portion 42 and the front high fiber lump content portion 43 .

In the front high fiber mass content portion 43, the fiber masses 11 may be distributed in any way, or may be uniformly distributed throughout the front high fiber mass content portion 43. The thickness of the front high fiber mass content portion 43 Although it may be unevenly distributed in a part of the direction, the non-skin facing surface 46 side of the front high fiber lump content portion 43 should have a higher fiber lump occupancy than the skin facing surface 45 side located on the opposite side. is preferred. The above points are the same as those of the rear high fiber mass content portion 42 . In the present embodiment, such a magnitude relationship "fiber lump occupation rate on the non-skin facing surface 46 side > fiber lump occupation rate on the skin facing surface 45 side" is established, and as shown in FIG. In the portion 43, the fiber lumps 11 are unevenly distributed on the non-skin-facing surface 46 side, and the core-forming materials other than the fiber lumps 11 (in this embodiment, the water-absorbing fibers 12F and the water-absorbing polymer 13) are unevenly distributed on the skin-facing surface 45 side. are doing.

By establishing the above-described size relationship in the front side fiber lump high content portion 43, the effect of mainly the fiber lump 11, such as the effect of improving flexibility and cushioning properties, is enhanced, and the effect on the wearer's excretory part such as the vaginal opening is enhanced. Fit and leakproofness can be further improved. The mechanism is basically the same as that of the rear high fiber lump content portion 42, and unless otherwise specified, the above description of the rear high fiber lump content portion 42 is appropriately applied.

In addition, a region sandwiched between a pair of recessed portions 7 (outer vertical recessed portions 7X1) extending in the longitudinal direction X in the front high fiber mass content portion 43 has a low density lower than that of the recessed portions 7. In the low-density portion, since the plurality of fiber lumps 11 exist in a state in which the original outer shape is substantially maintained, there is a gap formed between the plurality of fiber lumps 11. A large number of space portions are present, and the large number of space portions contribute to the expression of the excellent cushioning properties of the low-density portion, and can also function as a temporary stock portion for body fluids. Since the napkin 1 of the present embodiment has the low-density portion that can function as a temporary stock portion for bodily fluids, in the excretion portion-facing region M, which is a portion where excreted bodily fluids tend to concentrate, It has excellent liquid absorption capacity and can exhibit high liquid leakage prevention properties, and its high liquid drawing property reduces liquid residue on the surface of the topsheet 2 facing the skin, thereby eliminating unpleasant wet and sticky feelings. can be suppressed. In addition, since the constituent fibers 11F of the fiber mass 11 are fibers having lower water absorption (weak water absorption fibers) than the water-absorbing fibers 12F, and are preferably thermoplastic fibers, the front side fiber mass high content portion 43 The low-density portion can sufficiently exhibit the action and effect of the fiber mass 11 not only in a dry state before absorption of body fluid but also in a wet state after absorption of body fluid.

On the premise that the fiber lump occupation ratio of the non-skin facing surface 46 side of the front high fiber lump content portion 43 is higher than that of the skin facing surface 45 located on the opposite side in the thickness direction, it is preferably 50% by mass or more. , more preferably 90% by mass or more, and may be 100% by mass. That is, the non-skin-facing surface 46 side of the front side high fiber mass content portion 43 does not need to contain the water absorbent fibers 12F instead of containing the fiber mass 11 at all.
On the premise that the fiber mass occupancy on the skin facing surface 45 side of the front high fiber mass content portion 43 is lower than that on the non-skin facing surface 46 side located on the opposite side in the thickness direction, it is preferably 50% by mass or less. , more preferably 10% by mass or less, and may be 0% by mass. That is, the skin-facing surface 45 side of the front side fiber lump high content portion 43 does not need to contain the fiber lumps 11 at all instead of containing the absorbent fibers 12F.

On the premise that the basis weight of the fiber lumps 11 on the non-skin facing surface 46 side of the front high fiber lump content portion 43 is larger than that on the skin facing surface 45 side, it is preferably 32 g/m ² or more, more preferably 80 g. /m ² or more, preferably 640 g/m ² or less, more preferably 480 g/m ² or less.
On the premise that the basis weight of the fiber lumps 11 on the skin facing surface 45 side of the front high fiber lump content portion 43 is smaller than that on the non-skin facing surface 46 side, it is preferably 320 g/m ² or less, more preferably 240 g. /m ² or less, and may be 0 g/m ² .

The front high fiber mass content portion 43 may be present at least in the excretory portion-facing region M, and may be present in the front region F. In the absorbent body 4A shown in FIG. The boundary between the excretory part facing area M and the rear area R and the vicinity thereof are areas where a load is particularly likely to be applied when the wearer of the napkin 1 is in a sleeping posture, and such areas are excellent in cushioning properties. The rear side high fiber lump content portion 42 and the front side high fiber lump content portion 43 continuously exist across the boundary in the longitudinal direction X, so that the cushioning properties of the portion can be improved. Further, in the absorbent body 4A shown in FIG. 5, another rear high fiber lump content portion 42 is separated in the longitudinal direction X from the rear high fiber lump content portion 42 connected to the front high fiber lump content portion 43. have. Therefore, in the lying position, the wearer's buttocks have good cushioning properties, so that a comfortable wearing feeling can be obtained during sleep. In addition, the body fluid (menstrual blood) diffused from the front region F is blocked by the rear high fiber mass content portion 42, so that leakage of the body fluid (menstrual blood) from the dorsal side during sleep can be suppressed.

It should be noted that, as in the absorbent body 4A shown in FIG. It is preferable that a portion close to the edge in the longitudinal direction X is the portion having the minimum fiber mass occupation ratio.

As shown in FIGS. 1 and 2, the absorbent core 40 of this embodiment has a thick portion 47 that is thicker than the surrounding area and protrudes toward the user's skin in the excretory portion facing region M. As shown in FIG. More specifically, the thick portion 47 exists in a region sandwiched between a pair of concave portions 7 extending in the longitudinal direction X (outer longitudinal concave portions 7X1) in the front high fiber mass content portion 43. As shown in FIG. The thick portion 47 contains more core-forming materials such as the fiber lumps 11 and the absorbent fibers 12F than the peripheral portion. There is a quantity difference. Due to the presence of the thick portion 47 in the excretion portion-facing region M, the portion of the napkin 1 that overlaps with the thick portion 47 in plan view, typically the central portion in the horizontal direction Y of the excretory portion-facing region M, is the vaginal opening. Since it becomes easy to closely_contact|adhere to a wearer's excretory part, etc., the wearing feeling and liquid absorbency of the napkin 1 can further improve. In addition, a thick portion 47 exists in the front side high fiber mass content portion 43, and in the front side high fiber mass content portion 43, the fiber masses 11 are unevenly distributed on the non-skin facing surface 46 side as shown in FIG. That is, when the size relationship of "the fiber mass occupation rate on the non-skin facing surface 46 side>the fiber mass occupation rate on the skin facing surface 45 side" is established, the action effect of the fiber mass 11 is enhanced, and the fit is improved. and leakproofness can be further improved.

The thick portion 47 may be present at least in the absorbent core 40 in the excretory portion-facing region M. As shown in FIG. In the napkin 1 of the present embodiment, as shown in FIG. 2, the excretory portion-facing region M is present only in the central portion of the absorbent core 40 in the lateral direction Y, and is not present on both sides in the lateral direction Y. , over the entire length (entire width) of the lateral direction Y of the absorbent core 40 in the excretory part facing region M. Further, the thick portion 47 may exist in a portion other than the excretory portion-facing region M. For example, the thick portion 47 may extend from the excretory portion-facing region M to the front region F and/or the rear region R. good. Typically, the thick portion 47 is present at least in the central portion in the lateral direction Y of the absorbent core 40 in the excretory portion-facing region M. As shown in FIG.

In this embodiment, as described above, as shown in FIGS. 1 to 4, a pair of side sheets (leakage-preventive cuff forming sheets) 60, 60 are arranged on both sides along the longitudinal direction X of the absorbent body 5, Each side sheet 60 has an upright portion 62 that rises toward the wearer from a base end portion 61 to which the side sheet 60 is fixed to another member. It is preferable that the fiber clump 11 is present in a portion overlapping the standing portion 62 of the absorbent core 40 (absorbent body 4) in a plan view, which is located between the standing-up inhibiting portions 64, 64. As shown in FIG. Here, "overlapping with the standing portion 62 in plan view" means overlapping with the standing portion 62 in plan view when the napkin 1 is unfolded and stretched as shown in FIG. The "unfolded and stretched state" means that the napkin 1 is stretched by stretching the elastic members of each part to reach the design dimension (the same dimension as when spread flat with the influence of the elastic member completely eliminated). state. The portion of the absorbent core 40 that overlaps the standing portion 62 in a plan view is a portion that is particularly prone to twisting due to the influence of the tension of the standing portion 62 (elastic member 63), and the fiber mass 11 that is excellent in shape retention and the like is located in this portion. Due to the presence of this, twisting of the absorbent body 4 when the napkin 1 is worn is effectively prevented.

The content of the water-absorbent polymer 13 in the absorbent core 40 is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 80% by mass with respect to the total mass of the absorbent core 40 in a dry state. 50% by mass or less, more preferably 50% by mass or less. As used herein, the term "dry absorbent core" means an absorbent core before it absorbs bodily fluids.

The basis weight of the water absorbent fibers 12F in the absorbent core 40 is preferably 32 g/m ² or more, more preferably 80 g/m ² or more, and preferably 640 g/m ² or less, more preferably 480 g/m ² or less. be.
The basis weight of the water absorbent polymer 13 in the absorbent core 40 is preferably 5 g/m ² or more, more preferably 10 g/m ² or more, and preferably 200 g/m ² or less, more preferably 100 g/m ² or less. be.
The basis weight of the fiber lumps 11 in the absorbent core 40 is as described above.

The absorbent body 4 (absorbent core 40) can be manufactured according to a conventional method using a known fiber stacking device equipped with a rotating drum. As described above, the absorbent core 40 has a partially different distribution of the fiber clumps 11 (fiber clump occupancy) at least in the plane direction, and the distribution of the fiber clumps 11 (fiber clump occupancy) is different in the thickness direction as well. Although it may differ, any form can be manufactured according to a conventional method using a known fiber stacking device. For example, as shown in FIGS. 2 and 3, the configuration in which the fiber lumps 11 are unevenly distributed in the thickness direction can be achieved by a rotating drum of the fiber lumps 11 and the absorbent fibers 12F in the absorbent body manufacturing method using a known fiber stacking device. It can be manufactured by appropriately adjusting the stacking order and the like.

A fiber stacking device that can be used to manufacture the absorbent body 4 (absorbent core 40) typically includes a rotating drum having a collecting recess formed on its outer peripheral surface, and a core forming material (fiber mass) placed in the collecting recess. 11, a duct having a flow path for conveying the water-absorbent fiber 12F and the water-absorbent polymer 13) inside the rotating drum while rotating the rotating drum around the rotation axis along the drum circumferential direction The core forming material conveyed by the air flow generated in the flow path by suction from the side is piled up in the accumulating concave portion. The absorbent core 40 is formed in the stacking concave portion by such a stacking process.

As a method of manufacturing an absorbent body in which the fiber lumps 11 are unevenly distributed in the thickness direction, such as the absorbent body 4 shown in FIGS. mentioned.
1) A method of using two fiber stacking devices and stacking and integrating a fiber stack manufactured by one of the fiber stacking devices and a fiber stack manufactured by the other fiber stacking device (hereinafter referred to as "first method (Also referred to as “manufacturing method”).
2) A method of using a single fiber stacking device and differentiating the supply timing of the fiber clumps to the accumulating concave portion and that of the water-absorbing fibers (hereinafter also referred to as "second manufacturing method").

In the first manufacturing method, first, the water-absorbing fibers 12F and, if necessary, the water-absorbing polymer 13 are used as the core-forming material, and the core-forming material is accumulated in the accumulation concave portion of the first fiber stacking device. to produce a water-absorbent fiber pile. Separately from this, the fiber mass 11 is used as the core forming material, and the core forming material is accumulated in the collecting concave portion of the second fiber stacking device to manufacture a fiber mass piled body. Next, the water-absorbing fiber piled body and the fiber piled body are laminated to obtain a laminated body, and the laminated body is integrated by pressing in the thickness direction. As another integration method, suction means such as a known vacuum conveyor is used, the water-absorbing fiber piled body is placed on the suction surface of the suction means, and the suction force of the suction surface acts. In this state, the fiber mass piled body is superimposed on the water-absorbent fiber piled body to be integrated. In any integration method, entanglement occurs between the water-absorbent fibers and the fiber mass at the interface between the water-absorbing fiber pile and the fiber mass. In this way, an absorbent body such as the absorbent body 4 shown in FIGS. 2 and 3 is obtained in which the fiber lumps 11 (water absorbent fibers 12F) are unevenly distributed in the thickness direction.

In the second manufacturing method, as the fiber stacking device, a stacking recess having a partially different suction force is used. Specifically, for example, the stacking recess has a low suction recess and a Also, a high-suction concave portion with a high suction force is used. The low suction recesses and the high suction recesses are connected in the rotating direction (circumferential direction) of the rotating drum of the fiber stacking device. Then, the fiber stacking device having such a configuration is operated, and while the rotating drum is rotated in the circumferential direction to convey the stacking concave portion in one direction, the suction from the inside of the rotating drum causes the fiber to be drawn from the outside of the rotating drum. An air flow directed toward the accumulating recess is generated, and the core forming material is supplied to the accumulating recess by the air flow and accumulated (accumulating step). In the accumulating step, first, the fiber mass 11 is supplied to the accumulating concave portion and accumulated. At this time, the fiber lumps 11 are intensively accumulated in the high-suction concave portions, and fiber lump-stacked filaments are formed in the high-suction concave portions. Next, after or during the accumulation of the fiber lumps 11, the water-absorbing fibers 12F and, if necessary, the water-absorbing polymer 13 are supplied to the accumulation concave portion and accumulated. At this time, the water-absorbent fibers 12F (water-absorbent polymer 13) are accumulated in the low-suction recesses in the accumulation recesses, and are also accumulated on the fiber lumps 11 accumulated in the high-suction recesses. A water-absorbing fiber piled body is formed over the entire area. Since the fiber clumps 11 have air permeability, even when the fiber clumps 11 are accumulated in the high suction concave portion, a suction force capable of sucking the water-absorbent fibers 12F acts on the accumulated fiber clumps. The water absorbent fibers 12F (water absorbent polymer 13) can be piled up on the fiber clumps 11 accumulated in the high suction recesses. In this way, a laminate of the fiber mass and the water-absorbent fiber stack is formed in the high suction recess, and the fiber mass 11 and the water-absorbent fiber 12F are entangled at the interface between the two stacks. . In this way, absorbent bodies such as absorbent bodies 4B to 4E shown in FIGS. 2 and 3 are obtained in which the fiber lumps 11 (water absorbent fibers 12F) are unevenly distributed in the thickness direction.

The fiber mass 11 will be further described below. Various types can be used as the fiber mass 11 used in the present invention. A fiber mass 11A shown in FIG. 6, which is a preferred form, has a quadrangular prism shape, more specifically, a rectangular parallelepiped shape. The fiber clump 11A has two base planes 111 facing each other and a body plane 112 connecting the two base planes 111 . Both the basic surface 111 and the skeletal surface 112 are portions that are recognized to have substantially no unevenness at the level applied when evaluating the degree of unevenness of the surface of an article mainly composed of this type of fiber. The description of the fiber mass 11 in this specification also applies to embodiments of the fiber mass according to the present invention, such as the fiber mass 11A, unless otherwise specified.

In the fiber clump 11 , it is preferable that the number of skeletal planes 112 per unit area of fiber ends is larger than that of the basic planes 111 . Such fiber clumps 11 are obtained by cutting a raw fiber sheet (a sheet having the same composition as the fiber clumps 11 and having larger dimensions than the fiber clumps 11) with a cutting means such as a cutter. The skeletal surface 112 of the fiber mass 11 obtained in this manner is a cut surface formed by cutting the raw material fiber sheet, and thus the fiber end portion composed of the cut ends of the constituent fibers 11F formed by the cutting. are present throughout the skeletal surface 112 . That is, in the fiber mass 11 produced by cutting the raw material fiber sheet, the skeletal surface 112, which is the cut surface formed by the cutting, is closer to the basic surface 111, which is the non-cut surface at the time of manufacturing the fiber mass 11. In comparison, the number of fiber ends per unit area is high.

Fiber ends present on each surface (basic surface 111, skeletal surface 112) of the fiber mass 11 are located between the fiber mass 11 and other fiber masses 11 contained in the absorbent core 40 and the absorbent fibers 12F. Useful for forming entanglements. In general, the greater the number of fiber ends per unit area, the better the entanglement, which can lead to the improvement of various properties of the absorbent core 40 such as shape retention. The number of fiber end portions per unit area on each surface of the fiber mass 11 is not uniform, and the number of such fiber end portions per unit area has a size relationship of “skeletal surface 112>basic surface 111”. Therefore, the entanglement with other fibers (other fiber lumps 11, water-absorbing fibers 12F) via the fiber lumps 11 differs depending on the surface of the fiber lumps 11, and the skeletal surface 112 is different from the basic surface 111. Highly confounding. That is, the binding force by entangling with other fibers via the skeletal surface 112 is stronger than that via the basal surface 111, and in one fiber mass 11, the basal surface 111 and the skeletal surface 112 may cause a difference in bonding strength with other fibers. In general, the stronger the binding force, the more restricted the freedom of movement of the bound fibers, and the strength (shape retention) of the absorbent core 40 as a whole improves, but the softness tends to decrease. .

In this way, each of the plurality of fiber clumps 11 contained in the absorbent core 40 exerts two types of bonding strength with respect to other surrounding fibers (other fiber clumps 11, water absorbent fibers 12F). The absorbent core 40 thus has both moderate softness and strength (shape retention). When the absorbent core 40 having such excellent properties is used as an absorbent body of an absorbent article according to a conventional method, it is possible to provide a comfortable wearing feeling to the wearer of the absorbent article. At the same time, the inconvenience of the absorbent core 40 being destroyed by an external force such as body pressure of the wearer when worn is effectively prevented.

A nonwoven fabric piece (fiber mass) manufactured by cutting a raw fiber sheet into an irregular shape with a cutting machine such as a mill cutter is a regular sheet having a "surface" such as a basic surface 111 and a skeleton surface 112. Since the fiber clumps are not flake-like and the external force of the cutting process is applied to the entire fiber clump during its production, the fiber ends of the constituent fibers are randomly formed throughout the fiber clump. Compared with the fiber mass produced in this manner, the fiber mass 11 of the present embodiment described above, for example, the fiber mass 11A shown in FIG.

From the viewpoint of ensuring the effects of the fiber end portions described above, the number N1 of fiber end portions per unit area of the basic surface 111 (non-cut surface when manufacturing the fiber mass 11) and the skeleton surface 112 The ratio of the number N2 of the fiber ends per unit area of (the cut surface at the time of manufacturing the fiber mass 11) is preferably 0 or more, more preferably 0.05 or more as N1/N2 on the premise of N1<N2. , and preferably 0.90 or less, more preferably 0.60 or less. More specifically, N1/N2 is preferably 0 or more and 0.90 or less, more preferably 0.05 or more and 0.60 or more.
The number N1 of fiber ends per unit area of the basic surface 111 is preferably 0/mm ² or more, more preferably 3/mm ² or more, and preferably 8/mm ² or less, more preferably 6. pcs/mm ² or less.
The number N2 of fiber ends per unit area of the skeletal surface 112 is preferably 5/mm ² or more, more preferably 8/mm ² or more, and preferably 50/mm ² or less, more preferably 40. pcs/mm ² or less.
The number of fiber ends per unit area of the basic surface 111 and the skeletal surface 112 is measured by the following method.

<Method for measuring the number of fiber ends per unit area on each surface of the fiber mass>
A member (fiber mass) containing fibers to be measured is attached to a sample table using a double-sided paper tape (Nichiban Co., Ltd., Nicetac NW-15). The measuring piece is then platinum coated. An ion sputtering apparatus E-1030 (trade name) manufactured by Hitachi Naka Seiki Co., Ltd. is used for coating, and the sputtering time is 120 seconds. Using a JCM-6000 type electron microscope manufactured by JEOL Co., Ltd., the basal plane and skeletal plane of the cut surface of the measurement piece are observed at a magnification of 100 times. In this observation screen with a magnification of 100 times, a rectangular area of 1.2 mm in length and 0.6 mm in width is set at an arbitrary position on the surface to be measured (basic surface or skeletal surface), and the area of the rectangular area is After adjusting the observation angle and the like so that 90% or more of the area of the observation screen is occupied, the number of fiber ends included in the rectangular area is measured. However, in the observation screen with a magnification of 100 times, when the measurement target surface of the fiber mass is smaller than 1.2 mm × 0.6 mm and the ratio of the area of the rectangular region to the entire observation screen is less than 90% After increasing the observation magnification to 100 times or more, the number of fiber ends included in the rectangular area on the measurement target surface is measured in the same manner as described above. Here, the "fiber ends" to be measured are the ends in the length direction of the constituent fibers of the fiber mass, and the portions other than the ends in the length direction of the constituent fibers from the surface to be measured (middle in the length direction) part) is extended, the intermediate part in the length direction shall not be counted. Then, the number of fiber ends per unit area on the measurement target surface (basic surface or skeletal surface) of the fiber clump is calculated by the following formula. For each of the 10 fiber clumps, according to the above procedure, measure the number of fiber ends per unit area on each of the basic plane and the skeletal plane, and take the average value of these multiple measured values as the fiber end on the measurement target plane. number per unit area.
The number of fiber ends per unit area (number/mm ² ) on the measurement target surface (basic surface or skeletal surface) of the fiber mass = the number of fiber ends included in the rectangular area (1.2 × 0.6 mm)/ Area of said rectangular region (0.72 mm ² )

When the basic surface 111 of the fiber mass 11 has a rectangular shape in plan view like the fiber mass 11A shown in FIG. One side (short side) 111a of the quadrangular shape is preferably equal to or shorter than the thickness of the absorbent body 4 containing the fiber lumps 11 . The ratio of the length of one side (short side) 111a to the thickness of the absorbent body 4 is preferably 0.03 or more, more preferably 0.08 or more, and preferably 1 or less, more preferably 0 as the former/latter. .5 or less.
The thickness of the absorbent body 4 (absorbent core 40) is preferably 1 mm or more, more preferably 2 mm or more, and preferably 30 mm or less, more preferably 20 mm or less.

It is preferable to set the dimensions of each part of the fiber mass 11 as follows. The dimensions of each part of the fiber mass 11 can be measured based on an electron micrograph or the like during the later-described operation of specifying the outer shape of the fiber mass 11 .
When the basic surface 111 has a rectangular shape in plan view as shown in FIG. 6, the length L1 of one side (short side) 111a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and still more preferably 0.5 mm. and preferably 10 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less.
When the fiber mass 11 has a rectangular shape in plan view, the length L2 of the other side (long side) 111b of the basic surface 111 is preferably 0.3 mm or more, more preferably 1 mm or more, and still more preferably 2 mm or more. And it is preferably 30 mm or less, more preferably 15 mm or less, still more preferably 10 mm or less.
As shown in FIG. 6, when the basic surface 111 is the surface having the largest area among the plurality of surfaces of the fiber mass 11, the length L2 of the other side (long side) 111b is the length L2 of the fiber mass 11. corresponds to the maximum span length of For example, when the fiber mass 11 is disc-shaped, this maximum span length has two opposing flat surfaces that are circular in plan view and a curved peripheral surface that connects the two flat surfaces. , when the two flat surfaces are the basic surface 111 and the peripheral surface is the skeletal surface 112, they match the diameter of the basic surface 111 which is circular in plan view.
The ratio of the length L1 of one side (short side) 111a to the length L2 of the other side (long side) 111b is preferably 0.003 or more, more preferably 0.025 or more as L1/L2, and It is preferably 1 or less, more preferably 0.5 or less. In the present invention, the planar shape of the basic surface 111 is not limited to a rectangular shape as shown in FIG. 6, but may be a square shape. 1 may be used as L2.
The thickness T of the fiber mass 11, that is, the length T between the two opposing basic surfaces 111 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and preferably 10 mm or less, more preferably 6 mm or less. be.
The size of the fiber clump 11 is not particularly limited, and can be appropriately set in consideration of the cushioning properties, liquid permeability, and the like of the absorbent core 40 . The area of the basic plane 111 , which is the plane having the largest area among the plurality of planes of the fiber mass 11 , can serve as an indicator of the size of the fiber mass 11 . The area of the basic surface 111 of the fiber mass 11 is preferably 1 mm ² or more, more preferably 5 mm ² or more, and preferably 100 mm ² or less, more preferably 50 mm ^{2 or} less.

FIG. 7(a) shows an electron micrograph of one embodiment of the fiber clump 11, and FIG. 7(b) shows a diagram schematically showing the fiber clump 11 based on this electron micrograph. there is As shown in FIG. 7, the fiber mass 11 includes a main body portion 110 and fibers 11F extending outward from the main body portion 110, and has a lower fiber density (per unit area) than the main body portion 110. (lower number of fibers per fiber), and those with extended fiber portions 113 may be included. Note that the absorbent core 40 may also include fiber clumps 11 that do not have extended fiber portions 113 , that is, fiber clumps 11 that are composed only of main body portions 110 . The extended fiber portion 113 can include one type of fiber end portion present on each surface (the basic surface 111 and the skeletal surface 112) of the fiber mass 11 described above, and it is one of the fiber ends. Extending outwardly from each face of mass 11 are fiber ends.

The extending fiber portion 113 mainly contributes to improving the entanglement between the plurality of fiber lumps 11 contained in the absorbent core 40 or between the fiber lumps 11 and the water absorbent fibers 12F, thereby improving the shape retention of the absorbent core 40. In addition to being directly related to the improvement of , the uniform dispersibility of the fiber lumps 11 in the absorbent core 40 is also affected, and the effects of the main body 110 can be indirectly reinforced.

As shown in FIG. 7(b), the fiber mass 11 is a type of the extended fiber portion 113, and is an extended fiber bundle containing a plurality of fibers 11F extending outward from the main body portion 110, more specifically, from the skeletal surface 112. It has a part 113S. At least one of the extended fiber portions 113 included in the fiber clump 11 may be the extended fiber bundle portion 113S. The extending fiber bundle portion 113S is configured by gathering a plurality of fibers 11F extending from the skeletal surface 112. Compared to the extending fiber portion 113, the extending fiber bundle portion 113S extends from the skeletal surface 112 of the main body portion 110. Characterized by a point of long length. The extending fiber bundle portion 113S can also exist on the basic surface 111, but typically exists on the skeleton surface 112 as shown in FIG. However, the number thereof is smaller than that of the skeletal surface 112 . The reason for this is the same as the reason that the extended fiber portions 113 are mainly present on the skeletal surface 112, which is the cut surface of the raw material fiber sheet, as described above. Since the fiber clump 11 has such extended fiber bundle portions 113S, which can be called long and thick large-sized extended fiber portions 113, the fiber clumps 11 and the absorbent fibers 12F can be separated from each other. The entanglement is further strengthened, and as a result, the predetermined effects of the present invention due to the presence of the fiber clumps 11 are exhibited more stably. In addition, when the extended fiber bundle portion 113S has a heat-sealed portion, the strength of the extended fiber bundle portion 113S itself is improved, and entanglement occurs via the extended fiber bundle portion 113S. This is preferable because the entanglement between the fiber clumps 11 or between the fiber clumps 11 and the absorbent fibers 12F is further strengthened.

The constituent fibers 11F of the fiber mass 11 include fibers having lower water absorption (weak water absorption fibers) than the water absorbent fibers 12F. Here, the “weakly absorbent fibers” include “non-absorbent fibers” that do not absorb water, and “weakly absorbent fibers” that have water absorption but lower water absorption than the absorbent fibers 12F. and are included.

The water absorbency of the fiber can be indexed by the moisture content measured by the method described below. The higher the moisture content, the higher the water absorbency. The water content of the absorbent fibers 12F is preferably 6% or more, more preferably 10% or more. On the other hand, the moisture content of the weakly absorbent fibers that can be used as the constituent fibers 11F of the fiber mass 11 is preferably less than 6%, more preferably less than 4%.

<Method for measuring moisture content>
The moisture content was calculated according to the moisture content test method of JIS P8203. That is, after the fiber sample was allowed to stand in a test room at a temperature of 40° C. and a relative humidity of 80% RH for 24 hours, the weight W (g) of the fiber sample before absolutely dry treatment was measured in the room. After that, the fiber sample was completely dried by allowing it to stand for 1 hour in an electric dryer (manufactured by Isuzu Manufacturing Co., Ltd.) at a temperature of 105±2°C. After the absolute dry treatment, in a standard test room at a temperature of 20 ± 2 ° C. and a relative temperature of 65 ± 2%, Si silica gel (for example, (Toyota Kako Co., Ltd.) is placed in a glass desiccator (for example, manufactured by TechJam Co., Ltd.) and allowed to stand until the temperature of the fiber sample reaches 20±2°C. After that, the constant weight W' (g) of the fiber sample is weighed, and the moisture content of the fiber sample is obtained by the following formula. Moisture content (%) = (WW'/W') x 100

The constituent fibers 11F of the fiber mass 11 may contain fibers other than the weakly absorbent fibers, that is, the absorbent fibers 12F, but it is preferable that the fibers are mainly composed of the weakly absorbent fibers. The content of weakly absorbent fibers in the fiber mass 11 is preferably 90% by mass or more with respect to the total mass of the fiber mass 11, and 100% by mass, that is, all of the constituent fibers 11F are weakly absorbent fibers. is most preferred. Since the fiber clump 11 is composed mainly of weakly absorbent fibers, the absorbent core 40 is not only in a dry state but also in a wet state by absorbing water (bodily fluids such as urine and menstrual blood). Even in such a case, the effects (effects of improving flexibility, cushioning properties, compression recovery properties, shape retention properties, etc.) due to the presence of the fiber clumps 11 described above can be stably exhibited.

As the material of the constituent fibers 11F of the fiber clump 11, synthetic resin is preferable, and thermoplastic resin is particularly preferable. That is, the "weakly water-absorbing fiber" is preferably a synthetic fiber mainly composed of a synthetic resin, and particularly preferably a thermoplastic fiber mainly composed of a thermoplastic resin. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; These can be used alone or in combination of two or more. The fiber 11F may be a single fiber made of one type of synthetic resin (thermoplastic resin) or a blend polymer in which two or more types of synthetic resin are mixed, or may be a composite fiber. The composite fiber referred to here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more types of synthetic resins with different components with a spinneret and simultaneously spinning them, and multiple components are continuous in the length direction of the fiber. It is a structure that is bonded to each other within a single fiber. The form of the composite fiber includes core-sheath type, side-by-side type, etc., and is not particularly limited.

Although the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments and can be modified as appropriate.
In the above-described embodiment, the upright portion 62 of the leakage-preventing cuff 6 includes an inner extension portion 620 and an outer extension portion 622. However, the configuration of the upright portion 62 is not limited to this. The extending portion 622 may be omitted.
The absorbent article of the present invention broadly includes articles used for absorbing bodily fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body. So-called unfolded disposable diapers with tapes, underpants-type disposable diapers, incontinence pads and the like are included.

1 sanitary napkin (absorbent article)
F Front region M Excretion part facing region R Rear region 2 Top sheet 3 Back sheet 4, 4A Absorbent body 40 Absorbent core 41 Core wrap sheet 42 Rear high fiber mass content part 43 Front high fiber mass content part 45 Absorber or absorbent Skin-facing surface of absorbent core 46 Absorbent body or non-skin-facing surface of absorbent core 47 Thick portion 5 Absorbent main body 51 Front flap portion 52 Rear flap portion 53 Side flap portion 54 Front flap portion fixing member 55 Rear flap portion fixing member 6 leak-proof cuff 60 side sheet (sheet for forming leak-proof cuff)
61 base end portion 62 standing portion 620 inner extending portion 621 folded portion 622 outer extending portion 63 elastic member 64 standing inhibiting portion 65 end portion fixing portion 7, 7X1, 7X2, 7Y1, 7Y2 concave portion 11 fiber mass 11F fiber mass Constituent fiber (synthetic fiber)
REFERENCE SIGNS LIST 110 body portion 111 basic surface 112 skeletal surface 113 extended fiber portion 12F water absorbent fiber 13 water absorbent polymer

Claims (9)

The excretory part-facing region has a vertical direction corresponding to the front-rear direction of the wearer and a lateral direction perpendicular to the longitudinal direction, and is arranged to face the wearer's excretion part when worn, and a longitudinally front side of the excretory part-facing region. and a rear region arranged longitudinally behind the excretory part-facing region, and comprising an absorbent body and a surface sheet arranged on the skin-facing side of the absorbent body. and a pair of rear flap portions located in the rear region and comprising members extending laterally outward from both longitudinal side edges of the absorbent main body An absorbent article comprising
The absorber contains water-absorbent fibers and fiber lumps containing fibers having lower water absorbency than the water-absorbent fibers, and the plurality of fiber lumps or the fiber lumps and the water-absorbent fibers are entangled. and
In the surface direction of the absorbent body, the ratio of the mass content of the fiber lumps to the total mass content of the fiber lumps and the water-absorbing fibers is partially different,
An absorbent article, wherein the absorbent body has a rear side fiber lump high content portion having a higher ratio than a portion of the absorbent body having the minimum ratio in a region sandwiched between the pair of rear flap portions. 2. The absorbent article according to claim 1, wherein said ratio of said rear side fiber lump high content portion is 30% by mass or more. a recessed portion in which the surface sheet and the absorbent body are integrally recessed on the non-skin-facing side of the absorbent body at a position vertically overlapping the rear high fiber mass content portion; 3. The absorbent article according to claim 1 or 2, wherein a pair of said absorbent articles are present with a predetermined interval in the lateral direction. 4. The area according to claim 3, wherein the area between the pair of recessed portions at the position vertically overlapping the rear high fiber mass content portion has a larger ratio than the area outside the area in the lateral direction. absorbent article. A recessed portion different from the pair of recessed portions extends in the longitudinal direction and extends in the lateral direction in the region sandwiched between the pair of recessed portions at the position overlapping the rear high fiber mass content portion in the longitudinal direction. A pair exists at a predetermined interval at
3 or 4, wherein the area sandwiched between the pair of other recessed portions at the position overlapping the rear high fiber mass content portion in the longitudinal direction has a larger ratio than the area outside the area in the lateral direction. 5. The absorbent article according to 4. 6. The absorbent body according to any one of claims 1 to 5, wherein the absorbent body has, in the excretion part-facing region, a front side fiber mass-rich portion having a higher ratio than a portion having the smallest ratio in the absorbent body. The absorbent article described. 7. The absorbent article according to claim 6, wherein the front side portion with a high fiber mass content is connected to the rear side portion with a high fiber mass content. 8. The absorbent article according to claim 6, wherein in said front side high fiber mass content portion and said back side high fiber mass content portion, said ratio is higher on the non-skin facing side than on the skin facing side. A pair of side sheets are arranged on both sides along the longitudinal direction of the absorbent main body, and the pair of side sheets extend toward the wearer from base ends where the side sheets are fixed to other members. Having a standing part in a part of the vertical direction,
The absorbent article according to any one of claims 1 to 8, wherein the fiber clumps are present in a portion of the absorbent body that overlaps with the upright portion in a plan view.

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