Absorbent article

Abstract

To provide an absorbent article that fits well across front and rear portions of a wearer and can prevent leakage of body fluids.SOLUTION: An elongated absorbent article including a skin-side topsheet, a non-skin-side backsheet, and an absorbent body disposed between the topsheet and the backsheet, wherein the absorbent body has a medium basis weight portion and a low basis weight portion adjacent to the medium basis weight portion and having a basis weight lower than that of the medium basis weight portion, the low basis weight portion including a front low basis weight portion and a rear low basis weight portion having a width shorter than that of the front low basis weight portion, and a longitudinal length of the front low basis weight portion being 40% to 120% of a transverse length of the absorbent body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As absorbent articles such as sanitary napkins, there are known products for long-term or nighttime use that are long enough to face the rear of the wearer's buttocks. For such absorbent articles, a structure has been developed that allows the main body to fit closely to the rear of the body and prevent leakage of bodily fluids.

[0003] For example, Patent Document 1 describes an absorbent article in which an intermediate region extending in the width direction is formed behind the center of the wing in the front-rear direction and in front of the rear edge of the absorbent core, and the basis weight of the absorbent material in the intermediate region is lower than the basis weight of the first and second regions before and after the intermediate region. It also describes that this configuration prevents rearward leakage of bodily fluids when the wearer is lying on their back. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-67820 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even with the conventional configuration described above, if the wearer makes large movements while wearing the device, the device may not be able to maintain a good fit to the body, and there is still concern about leakage of bodily fluids. Therefore, there is a demand for a device that can maintain a good fit to the body even during movement.

[0006] Therefore, an object of one aspect of the present invention is to provide an absorbent article that has an excellent fit over the front and back of the wearer's body and can prevent leakage of bodily fluids. [Means for solving the problem]

[0007] A first aspect of the present invention is an elongated absorbent article comprising a skin-side top sheet, a non-skin-side back sheet, and an absorbent body arranged between the top sheet and the back sheet, wherein the absorbent body has a central basis weight portion and a low basis weight portion adjacent to the central basis weight portion and having a lower basis weight than the central basis weight portion, the low basis weight portion including a front low basis weight portion and a rear low basis weight portion having a width shorter than that of the front low basis weight portion, and the longitudinal length of the front low basis weight portion is 40 to 120% of the lateral length of the absorbent body.

[0008] According to the first aspect, when worn, the rear low basis weight portion, which is located at the rear and has a short horizontal length, can easily bulge toward the top sheet. This bulge forms a mound sized to fit the narrow part of the intergluteal cleft. This improves the fit to the intergluteal cleft and prevents leakage at the intergluteal cleft, such as leakage of bodily fluids from the bodily fluid outlet down the intergluteal cleft to the rear (also known as trailing leakage).

[0009] Furthermore, in this embodiment, a front low basis weight portion having a predetermined longitudinal length is formed. Therefore, the portion forward of the rear low basis weight portion can be flexibly deformed over a wide range. Therefore, even when the wearer opens and closes their legs or moves their legs back and forth, the absorbent article main body can deform in response to changes in the shape of the crotch area forward of the intergluteal cleft. In particular, if the above-mentioned rear low basis weight portion is protruded relatively deeply into the intergluteal cleft, the region of the main body facing the intergluteal cleft becomes less likely to move and deform. As a result, the region forward of the intergluteal cleft-facing region may also be less likely to deform. However, according to this embodiment, a front low basis weight portion that allows for flexible deformation over a wide range is formed in front of the rear low basis weight portion, allowing the absorbent article main body to fit deeply into the intergluteal cleft while also providing excellent fit to the body part forward of the intergluteal cleft. Thus, according to this aspect, a high level of fit can be obtained over a wide area along the front-to-back direction of the body, particularly from the perineum to the posterior intergluteal cleft, and this fit can be maintained even during movement.

[0010] In a second aspect of the present invention, the lateral length of the front low basis weight portion is equal to the lateral length of the absorbent body.

[0011] According to the second aspect, the front low basis weight portion can be flexibly deformed in the lateral direction, which improves the fit of the garment when the wearer is moving.

[0012] In a third aspect of the present invention, the lateral length of the rear low basis weight portion is 5 to 25% of the lateral length of the absorbent body.

[0013] According to the third aspect, the width of the ridge formed by the rear low basis weight portion can be set to an appropriate size to fit the deep part of the intergluteal cleft.

[0014] In a fourth aspect of the present invention, the intermediate weight portion includes a front intermediate weight portion adjacent to the front of the front low weight portion, and a rear intermediate weight portion adjacent to the rear of the front low weight portion and adjacent to both sides and the rear of the rear low weight portion, and at least the top sheet and the absorbent body are formed with compressed grooves that are recessed from the top sheet side to the back sheet side, and the compressed grooves include a pair of central compressed grooves that extend along the longitudinal direction of a body fluid discharge outlet facing region that faces the wearer's body fluid discharge outlet when worn, and the pair of central compressed grooves extend rearward beyond the rear ends of the front low weight portions.

[0015] According to the fourth aspect, the pair of central compressed grooves can prevent the rapid lateral diffusion of bodily fluids and guide the bodily fluids along the longitudinal direction, thereby preventing leakage. It can also promote appropriate deformation of the region facing the bodily fluid outlet.

[0016] Furthermore, generally, when compressed grooves are formed in areas of the absorbent body with a low basis weight, the applied compressive force is weaker than in other areas, and the compressed grooves may not be formed reliably. Furthermore, if the compression at the tips of the compressed grooves is insufficient, the parts that were compressed and joined in the thickness direction may peel off (so-called lifting occurs), and the compressed grooves may not be able to perform their function. In contrast, in this embodiment, the pair of central compressed grooves extend rearward beyond the rear ends of the front low basis weight sections, that is, the rear ends of the pair of central compressed grooves extend into the rear intermediate basis weight section adjacent to the rear of the front low basis weight sections, so lifting at the ends of the central compressed grooves can be prevented and the compressed grooves can function properly.

[0017] In a fifth aspect of the present invention, a varying basis weight portion is formed between the front low basis weight portion and the rear middle basis weight portion, and the basis weight in the varying basis weight portion is higher than the basis weight of the front low basis weight portion and lower than the basis weight of the rear middle basis weight portion, and gradually or stepwise increases toward the rear.

[0018] According to the fifth aspect, the varying basis weight portion can prevent abrupt changes in basis weight in the longitudinal direction, so that unnecessary stress is not generated in the region from the front low basis weight portion to the rear middle basis weight portion, and deformation along the shape of the body is possible. This allows for flexible deformation in the region from the perineum facing region to the intergluteal cleft facing region.

[0019] In a sixth aspect of the present invention, the absorbent body further has, in a region facing the bodily fluid discharge outlet that faces the bodily fluid discharge outlet of the wearer when worn, a high basis weight portion that is surrounded by the front middle basis weight portion and has a basis weight higher than that of the front middle basis weight portion.

[0020] According to the sixth aspect, the high basis weight portion in the region facing the bodily fluid discharge outlet allows the absorbent article main body to be in close contact with the bodily fluid discharge outlet, thereby preventing leakage. In this aspect, the absorbent body includes at least three regions with different basis weights (a low basis weight portion, a medium basis weight portion, and a high basis weight portion).

[0021] A seventh aspect of the present invention is a method for manufacturing an absorbent body for an absorbent article, wherein the absorbent body has a medium basis weight portion and a low basis weight portion adjacent to the medium basis weight portion and having a lower basis weight than the medium basis weight portion, the low basis weight portion including a front low basis weight portion and a rear low basis weight portion having a width shorter than that of the front low basis weight portion, the longitudinal length of the front low basis weight portion is 40 to 120% of the lateral length of the absorbent body, the method comprising stacking absorbent material to become the absorbent body in an absorbent body form having a plurality of suction openings on its bottom surface and removing the form, the area ratio of the openings in the region corresponding to the front low basis weight portion is smaller than the area ratio of the openings in the region corresponding to the medium basis weight portion, and a non-perforated convex member is provided in the region corresponding to the rear low basis weight portion.

[0022] According to the seventh aspect, an absorbent article having the same effect as the first aspect can be manufactured. Furthermore, in the absorbent mold used in the manufacturing method of this aspect, the area ratio of the open holes on the bottom surface of the absorbent mold in the region corresponding to the front low basis weight portion is smaller than the area ratio of the open holes on the bottom surface of the absorbent mold in the region corresponding to the intermediate basis weight portion. That is, the difference in basis weight between the front low basis weight portion and the intermediate basis weight portion is achieved by varying the area ratio of the open holes on the bottom surface of the absorbent mold. Another method for varying the basis weight within the absorbent mold is to vary the bottom surface level by forming partial convex or concave portions on the bottom surface of the absorbent mold. This method allows for a comparatively easy and reliable production of differences in basis weight. However, because varying the bottom surface level creates a step between the regions, when attempting to form a wide-area low basis weight portion, the absorbent material (especially a fibrous material such as pulp) is likely to be torn at the edges of the step. Therefore, the absorbent body may tear at the step or the desired thickness may not be obtained during processes such as stacking the absorbent material, scraping the material, and demolding. In this embodiment, the front low basis weight portion is a low basis weight portion with a relatively long horizontal length, so the low basis weight is obtained by varying the area ratio of the open holes on the bottom surface rather than by varying the bottom surface level, thereby preventing problems such as tearing that may occur between the front low basis weight portion and the middle basis weight portion.

[0023] On the other hand, in this embodiment, a non-perforated convex member is provided in the region corresponding to the rear low basis weight portion, and this non-perforated convex member ensures the low basis weight of the rear low basis weight portion. The layer of absorbent material accumulated on the non-perforated convex member becomes thinner than the surrounding region by the thickness of the non-perforated convex member after the scraping process following fiber stacking, thereby ensuring a low basis weight. If a low basis weight for the rear low basis weight portion were to be achieved by reducing the area ratio of the open holes in the absorbent body bottom surface, as in the front low basis weight portion, without using a non-perforated convex member, the absorbent material drawn in the regions on both sides of the narrow non-perforated convex member (regions corresponding to the middle basis weight portion) would overlap, blurring the boundary and potentially preventing the area for the rear low basis weight portion from being secured. However, this embodiment avoids such a possibility. Thus, in this embodiment, the front low basis weight portion and the rear low basis weight portion are formed by different means according to the shape of each low basis weight portion. Therefore, the area for the low basis weight portion can be reliably secured without problems such as tearing of the absorbent body.

[0024] In an eighth aspect of the present invention, the intermediate weight portion includes a front intermediate weight portion adjacent to the front low weight portion and adjacent to the rear of the front low weight portion and adjacent to both sides and rear of the rear low weight portion, and a weight changing portion is formed between the front low weight portion and the rear intermediate weight portion, and the weight in the weight changing portion is larger than the weight of the front low weight portion and smaller than the weight of the rear intermediate weight portion, and gradually or stepwise increases toward the rear, and the area ratio of the openings in the region corresponding to the weight changing portion is larger than the area ratio of the openings in the region facing the front low weight portion and smaller than the area ratio of the openings in the region corresponding to the rear intermediate weight portion, and gradually or stepwise increases toward the rear.

[0025] According to the eighth aspect, an absorbent article can be manufactured that has the same effects as the fifth aspect. Furthermore, by varying the basis weight between the rear low basis weight portion and the rear intermediate basis weight portion, a sudden change in basis weight between the two portions can be avoided, thereby reducing the possibility of impairing the longitudinal continuity of the absorbent body.

[0026] In a ninth aspect of the present invention, the absorbent body further has, in a region facing the bodily fluid discharge outlet that faces the wearer's bodily fluid discharge outlet when worn, a high basis weight portion that is surrounded by the front middle basis weight portion and has a basis weight higher than that of the front middle basis weight portion, and the region corresponding to the high basis weight portion is a recess formed in the region corresponding to the front middle basis weight portion.

[0027] According to the ninth aspect, an absorbent article can be manufactured that has the same effects as the sixth aspect. Furthermore, a high basis weight portion, which is a region with an even higher basis weight, can be formed in a region within the front intermediate weight portion. In this case, the open area ratio of the bottom surface of the region facing the high basis weight portion may be the same as the open area ratio of the region corresponding to the front intermediate weight portion, or may be greater than the open area ratio of the region corresponding to the front intermediate weight portion. [Effects of the Invention]

[0028] According to one aspect of the present invention, it is possible to provide an absorbent article that has an excellent fit over the front and back of the wearer's body and is capable of preventing leakage of bodily fluids. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a plan view of an absorbent article according to one embodiment, viewed from the skin side. [Figure 2] This is a cross section taken along line II in Figure 1. [Figure 3] This is a cross section taken along line II-II in Figure 1. [Figure 4] FIG. 2 is a plan view of the absorbent article of FIG. 1 with the absorbent body exposed. [Figure 5] FIG. 5 is a partially enlarged view of the absorbent body shown in FIG. [Figure 6] FIG. 2 is a schematic cross-sectional view showing the absorbent article in a worn state. [Figure 7] 10A and 10B are diagrams showing other variations of the planar shape of the low basis weight portion. [Figure 8] FIG. 10 is a plan view of an absorbent article according to a modified example, with the absorbent body exposed. [Figure 9] FIG. 9 is a partially enlarged view of FIG. 8. [Figure 10] FIG. 1 is a schematic diagram showing an absorbent article manufacturing apparatus. [Figure 11] 1 is a plan view of an absorbent mold used in a manufacturing method of an absorbent article according to the present embodiment. FIG. [Figure 12] FIG. 12 is a partial enlarged view of FIG. 11 (an enlarged view of a portion P1 and a portion P2). [Figure 13] FIG. 12 is a cross-sectional view of FIG. [Figure 14] FIG. 10 is a plan view of an absorbent body mold used in a modified method for manufacturing an absorbent article. [Figure 15] FIG. 15 is a partially enlarged view of FIG. 14 (an enlarged view of a portion P3). [Figure 16] FIG. 15 is a cross-sectional view of FIG. [Figure 17] FIG. 10 is a plan view for explaining the folding position when individually packaging. [Figure 18] FIG. 18 is a schematic cross-sectional view taken along line III-III in FIG. [Figure 19] FIG. 18 is a schematic cross-sectional view of an individually packaged absorbent article obtained from the state of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, unless otherwise specified, the same or corresponding components will be denoted by the same reference numerals and the description thereof will be omitted.

[0031] <Basic structure of absorbent articles> First, the basic structure of the absorbent article according to this embodiment will be described using an overnight or long-lasting sanitary napkin as an example. Fig. 1 shows a plan view of an absorbent article 1. Fig. 2 shows a cross-sectional view taken along line II in Fig. 1, and Fig. 3 shows a cross-sectional view taken along line II-II in Fig. 1.

[0032] As shown in Figures 1 to 3, the absorbent article 1 comprises a liquid-permeable topsheet 3 arranged on the side that faces the wearer's skin when worn, i.e., the skin side, and a liquid-impermeable backsheet 2 arranged on the non-skin side (underwear side) opposite the skin side. Furthermore, an absorbent body (absorbent core) 4 is arranged between the backsheet 2 and the topsheet 3. The backsheet 2, absorbent body 4, and topsheet 3 are layered to form a main body (absorbent article main body) 8. The absorbent body 4 is arranged so as not to protrude from the backsheet 2 and topsheet 3 in a plan view. At both end edges in the longitudinal direction D1, the edges of the backsheet 2 and the topsheet 3 may be joined by adhesive, heat sealing, or the like.

[0033] As shown in the figure, the absorbent article 1 is in the shape of an elongated pad (a shape in which the thickness is smaller than the width and length). In this specification, the longitudinal direction (front-to-back direction) of the absorbent article 1 is designated D1, and the lateral direction (left-to-right or width direction) perpendicular to the longitudinal direction D1 is designated D2. The longitudinal direction D1 corresponds to the front-to-back direction of the wearer's body when the absorbent article 1 is worn, and the lateral direction D2 corresponds to the left-to-right direction of the body.

[0034] 1 to 3, the main body 8 has a shape in plan view that is approximately line-symmetrical with respect to a center line (longitudinal center line) CL extending in the longitudinal direction D1, but the shape of the main body 8 does not necessarily have to be line-symmetrical. Furthermore, configurations other than the shapes of the absorbent article 1 and the main body 8 (including the thickness and density of the absorbent body 4, the size and position of the compressed grooves, and the shape and size of the flaps extending outward from the main body 8 in the lateral direction D2) may be approximately symmetrical or asymmetrical with respect to the center line CL as the axis of symmetry.

[0035] The backsheet 2 may be a sheet that is at least water-proof, for example, a sheet made of an olefin resin such as polyethylene or polypropylene. Alternatively, a laminated nonwoven fabric in which a nonwoven fabric is laminated on a polyethylene sheet or the like, or a laminated sheet of nonwoven fabric in which a waterproof film is interposed to ensure substantial liquid impermeability, may be used. Furthermore, it is more desirable to use a material that is moisture-permeable in order to prevent stuffiness. Examples of such water-proof and moisture-permeable sheet materials include microporous sheets obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet, and then stretching the sheet uniaxially or biaxially. The backsheet 2 may be a sheet having the same outer shape as the outer shape of the absorbent article 1.

[0036] The top sheet 3 can be a liquid-permeable sheet that allows bodily fluids such as menstrual blood, vaginal discharge, and urine to quickly pass through. Suitable top sheet 3 materials include perforated or non-perforated nonwoven fabrics and porous plastic sheets. Examples of material fibers constituting the nonwoven fabric include olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cupra, and blends thereof, as well as natural fibers such as cotton, which can be used alone or in combination. Examples of processing methods for nonwoven fabrics include spunlace, spunbond, thermal bond, meltblown, and needlepunch. Of these processing methods, the spunlace method is preferred because it provides flexibility, the spunbond method is preferred because it can produce nonwoven fabrics with excellent drapeability, and the thermal bond method is preferred because it can produce bulky and soft nonwoven fabrics. Composite fibers, such as core-sheath fibers, side-by-side fibers, and splittable fibers, each of which has a high-melting-point fiber as the core and a low-melting-point fiber as the sheath, can also be used.

[0037] The absorbent body 4 is not limited to any material that can absorb and retain body fluids, but preferably contains cotton-like pulp and a water-absorbent polymer. Examples of water-absorbent polymers that can be used include superabsorbent polymer (SAP), superabsorbent fiber (SAF), and combinations of these. Pulp includes chemical pulp obtained from wood, cellulose fibers such as dissolving pulp, and artificial cellulose fibers such as rayon and acetate. Hardwoods and softwoods are used as raw materials for chemical pulp, with softwoods being preferred due to their long fiber length.

[0038] Synthetic fibers may be blended into the absorbent body 4. Examples of synthetic fibers that can be used include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof. Two of these fibers can also be blended. Composite fibers, such as core-sheath fibers with a high-melting-point fiber as the core and a low-melting-point fiber as the sheath, side-by-side fibers, and splittable fibers, can also be used. Hydrophobic fibers can also be surface-treated with a hydrophilizing agent to impart affinity to body fluids. The absorbent body 4 is preferably manufactured by stacking or air-laid methods.

[0039] The absorbent body 4 may have a plurality of compressed absorbent body portions that are partially recessed from the top sheet 3 side toward the back sheet 2 side and are spaced apart from each other in a plan view. The absorbent body 4 may also be wrapped in an envelope sheet made of colored or uncolored (white) crepe paper, nonwoven fabric, or the like to prevent kinking, cracking, or spillage of polymer particles. The specific configuration of the absorbent body 4 and a preferred manufacturing method will be described in detail later.

[0040] Side sheets 7, 7 are arranged on both sides of the absorbent article 1, i.e., on the side in the lateral direction D2, along the longitudinal direction D1, facing the skin. The side sheets 7 may be made of a material that has been treated, entirely or partially, with an appropriate water-repellent or hydrophilic treatment, depending on the purpose, such as preventing penetration of bodily fluids or improving the feel against the skin. The side sheets 7 are preferably nonwoven fabrics containing natural fibers, synthetic fibers, recycled fibers, etc., or made from these fibers. When the side sheets 7 are nonwoven fabrics, they may be air-through nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, etc., but air-through nonwoven fabrics are preferred because they are resistant to creases, wrinkles, and soft, improving the feel against the skin. The side sheets 7 may also be treated with a water-repellent agent, such as a silicone-based or paraffin-based water-repellent agent.

[0041] The side sheet 7 may be folded back on the inside in the lateral direction D2 to form a multi-layered band-like portion extending along the side of the main body 8. Gathers may be formed by disposing an elastically stretchable member in a stretched state between the multiple layers along the longitudinal direction D1. In this specification, the configuration of the folds and gathers of the side sheet 7 will not be described, and will not be shown in the drawings.

[0042] The absorbent article 1 may have a body fluid discharge outlet-facing region C that faces the wearer's body fluid discharge outlet (the vaginal opening in the illustrated example) when worn, a front region F that is adjacent to the front of the body fluid discharge outlet-facing region C and extends to the front end of the absorbent article 1, a perineum-facing region (middle region) M that is adjacent to the rear of the body fluid discharge outlet-facing region C and faces the vicinity of the wearer's perineum when worn, and a buttocks-facing region B that is adjacent to the rear of the perineum-facing region M and extends to the rear end of the absorbent article 1 and faces the wearer's buttocks when worn. Furthermore, the buttocks-facing region B includes a front buttocks-facing region B1 that is adjacent to the perineum-facing region M, and a rear buttocks-facing region B2 that is adjacent to the rear of the front buttocks-facing region B1. The front buttocks-facing region B1 is a region that mainly faces the intergluteal cleft (gluteal groove) and faces the area including the anus. The rear buttock facing region B2 may be a region that can face a region behind the intergluteal cleft or further behind the rear end of the intergluteal cleft, in particular a region behind (above when standing) the intergluteal sulcus, which can be said to be the boundary between the buttocks and the legs. Note that the above description of the facing relationship between the region of main body 8 and the wearer's body can be considered to be an approximate range when the wearer wears the absorbent article in a normal manner while lying down, but this is merely a guideline.

[0043] The length in the longitudinal direction D1 of the bodily fluid outlet-facing region C may be 50 to 120 mm, and the length in the longitudinal direction D1 of the buttocks-facing region B may be 90 to 230 mm. Furthermore, the configuration of this embodiment is suitable for, for example, absorbent articles with a long rear, in which the total length of the perineum-facing region M and the buttocks-facing region B, preferably the length in the longitudinal direction D1 of the buttocks-facing region B, is longer than the length in the longitudinal direction D1 where the wing flaps WF are provided. Furthermore, the length in the longitudinal direction D1 of the front buttocks-facing region (gluteal cleft-facing region) B1 may be 40 to 100 mm, and the length in the longitudinal direction D1 of the rear buttocks-facing region B2 may be 40 to 120 mm. Furthermore, the total length in the longitudinal direction D1 of the absorbent article 1 may be 250 to 450 mm.

[0044] The absorbent article 1 may include a pair of wing flaps WF, WF extending outward in the lateral direction D2 from both sides of the region C facing the bodily fluid discharge opening. Anti-slip materials (not shown) may be provided on the non-skin sides of the wing flaps WF, WF, and this anti-slip material allows the wing flaps WF, WF to be folded back to the non-skin sides and attached to the underwear so that the underwear is sandwiched between the wing flaps WF, WF and the main body 8 when worn. This allows the absorbent article 1 to be securely fixed to the underwear. The wing flaps WF, WF are formed by joining the outward extending portions of the side sheets 7, 7 in the lateral direction D2 and the outward extending portion of the back sheet 2 in the lateral direction D2.

[0045] In addition, a pair of hip hold flaps HF, HF may be formed extending outward in the lateral direction D2 from the sides of the main body 8 from the perineum-facing region M to the buttocks-facing region B. The hip hold flaps HF, HF prevent leakage of bodily fluids at the rear of the absorbent article 1 and, by increasing the contact area with the buttocks, make it less likely that the entire absorbent article 1 will shift relative to the underwear, particularly in the lateral direction D2, thereby stabilizing the wearing position of the absorbent article 1. The hip hold flaps HF, HF may also be formed by joining the outward extensions in the lateral direction D2 of the side sheets 7, 7 and the outward extensions in the lateral direction D2 of the back sheet 2.

[0046] <Specific composition of the absorbent body> FIG. 4 shows a plan view of the absorbent article 1 of FIG. 1 with the top sheet 3 and side sheets 7, 7 removed, exposing the absorbent body 4. As shown in FIG. 4, the basis weight of the absorbent body 4, specifically the pulp basis weight (or fiber basis weight), is not uniform overall but varies depending on the location. The absorbent body 4 has a medium basis weight portion 4M, which is mainly of a medium basis weight, a high basis weight portion 4H, which has a higher basis weight than the medium basis weight portion 4M, and a low basis weight portion 4L, which has a lower basis weight than the medium basis weight portion 4M. The low basis weight portion 4L has a front low basis weight portion 4Lf, which is arranged in the perineum-facing region M and has the same width as the absorbent body 4, and a rear low basis weight portion 4Lb, which is arranged in the intergluteal cleft-facing region B1 and is elongated in the longitudinal direction D1. The rear low basis weight portion 4Lb is preferably formed in the center in the lateral direction D2, straddling the longitudinal centerline. The intermediate weight portion 4M may have a front intermediate weight portion 4Mf formed mainly in the bodily fluid outlet-facing region C, and a rear intermediate weight portion 4Mb formed mainly in the rear buttock-facing region B2. As described above, the absorbent body 4 contains pulp (or a fibrous material mainly composed of pulp) and a water-absorbent polymer, and it is preferable that the water-absorbent polymer has a similar weight per unit area throughout the absorbent body 4. In this case, the relative magnitudes of the pulp weight per unit area are reflected in the relative magnitudes of the weight per unit area.

[0047] The basis weight of the low basis weight portion 4L may be preferably 200 to 500 gsm, more preferably 300 to 400 gsm. The basis weight of the medium basis weight portion 4M may be preferably 300 to 600 gsm, more preferably 400 to 500 gsm. The basis weight of the high basis weight portion 4H may be preferably 500 to 850 gsm, more preferably 600 to 750 gsm. In order to maximize the effect of the low basis weight portion 4L in this embodiment, the basis weight of the low basis weight portion 4L may be 60 to 90% of the basis weight of the medium basis weight portion 4M. The above basis weight may be a pulp basis weight.

[0048] The low basis weight portion 4L, the medium basis weight portion 4M, and the high basis weight portion 4H may be uniform basis weight regions in which the basis weight is approximately uniform within each portion. A substantially uniform basis weight within a specified portion or specified region means that even if there are some areas where the basis weight varies slightly, the difference from the average basis weight within the specified portion or specified region is 20% or less, preferably 10% or less, and more preferably 5% or less of the average basis weight. The front low basis weight portion 4Lf and the rear low basis weight portion 4Lb may have different basis weights, each of which has an approximately uniform basis weight. In this case, the basis weight of the rear low basis weight portion 4Lb may be slightly smaller than that of the front low basis weight portion 4Lf.

[0049] FIG. 5 shows an enlarged view of the region including the low basis weight portion 4L in FIG. 4. As shown in FIGS. 4 and 5, the rear low basis weight portion 4Lb is surrounded on both sides and at the rear by a medium basis weight portion 4M. The rear low basis weight portion 4Lb is more flexible than its surroundings, and when a force is applied from the outside in the lateral direction D2, it can easily be raised toward the top sheet 3. This allows for the formation of a narrow mound that fits even in the narrow position of the intergluteal cleft. Furthermore, as shown in FIGS. 4 and 5, a medium basis weight portion 4M with a higher basis weight is disposed behind the rear low basis weight portion 4Lb. That is, the rear extension range of the rear low basis weight portion 4Lb is short of the rear end of the absorbent body 4, preferably to the vicinity of the boundary between the intergluteal cleft-facing region B1 and the rear buttock-facing region B2. This prevents the mound formed by the rear low basis weight portion 4Lb from continuing to, for example, the rear end of the absorbent body 4. Therefore, the rear buttock facing region B2 can be easily fitted to a portion of the wearer where the intergluteal cleft is shallow or a relatively flat portion further rearward from the end position of the intergluteal cleft.

[0050] Furthermore, since the sides and rear of the rear low-weight portion 4Lb are made of medium-weight portions 4M, the sides of the intergluteal cleft-facing region B1 in the lateral direction D2 are slightly more rigid than the center in the lateral direction D2, making unwanted wrinkles and creases less likely to occur even when deformed. This makes it easier to fit the medium-weight portions 4M of the intergluteal cleft-facing region B1 to the surface of the buttocks on the sides of the intergluteal cleft. Furthermore, when folding the absorbent article 1 for individual packaging, even if a fold line is located in the medium-weight portions 4M, it is less likely to develop creases, and can be quickly unfolded to fit the underwear during putting on.

[0051] Furthermore, the length of the front low weight portion 4Lf in the longitudinal direction D1 is 40 to 120% of the lateral length of the absorbent body, allowing for flexible deformation over a wide range. Therefore, even when the wearer performs large movements such as opening and closing their legs or moving their legs back and forth, the absorbent article main body 8 can deform to accommodate changes in the shape of the body part below the crotch, effectively preventing leakage. In particular, if the raised mound of the rear low weight portion 4Lb described above is inserted relatively deeply into the intergluteal cleft, the intergluteal cleft-facing region B1 of the main body becomes less mobile, which can in turn make it difficult for the perineum-facing region M anterior to the intergluteal cleft-facing region B1 to deform. In contrast, the front low weight portion 4Lf extending across the lateral direction D2 can deform flexibly as described above, allowing it to accommodate changes in the shape of the body part anterior to the intergluteal cleft while maintaining close contact with the intergluteal cleft by the rear low weight portion 4Lb. Thus, according to this aspect, a high level of fit can be obtained over a wide area along the front-to-back direction of the body, particularly from the perineum to the posterior intergluteal cleft, and this fit can be maintained even during movement.

[0052] Fig. 6 shows a schematic cross-section of the absorbent article 1 taken along the lateral direction D2 when worn. Fig. 6(a) is a schematic cross-section of the absorbent article 1 taken at the perineum-facing region M, Fig. 6(b) is a schematic cross-section of the absorbent article 1 taken at the intergluteal cleft-facing region B1, and Fig. 6(c) is a schematic cross-section of the absorbent article 1 taken at the rear buttocks-facing region B2. As shown in Fig. 6(a), the perineum-facing region M faces the perineum in the crotch area between the legs Lg. Even when the legs Lg are closed or moved back and forth from this state, the perineum-facing region M includes the highly flexible front low-gauge portion 4Lf, so the perineum-facing region M can fit closely and conform to the perineum and surrounding body parts. As shown in Fig. 6(b), the intergluteal cleft-facing region B1 includes a rear low-weight portion 4Lb, which rises to form a mound, allowing the rear low-weight portion 4Lb to fit snugly into the cleft of the buttocks Den (gluteal cleft). Furthermore, as shown in Fig. 6(c), the rear buttock-facing region B2 includes a medium-weight portion 4M extending across the entire lateral direction D2, allowing the article to fit snugly against a relatively flat surface of a body part with a shallow or no intergluteal cleft. In other words, this embodiment provides an absorbent article that can be deformed to fit the shape of each part of the body, from the front to the back.

[0053] The length x of the front low basis weight portion 4Lf in the lateral direction D2 f The length x of the front low basis weight portion 4Lf in the lateral direction D2 is preferably 30 to 110 mm, and more preferably 60 to 100 mm. f From the viewpoint of improving the flexibility of the main body 8 in the lateral direction D2, the length y in the longitudinal direction D1 may be 70% or more, preferably 80% or more, of the length of the absorbent body 4 in the lateral direction D2, and more preferably is equal to the length of the absorbent body 4 in the lateral direction D2. f The length y in the longitudinal direction D1 is preferably 55 to 80 mm, and more preferably 60 to 70 mm. f is 40 to 120% of the length of the absorbent body 4 in the transverse direction D2, but may be more preferably 50 to 110%, and even more preferably 60 to 100%. f This allows the area facing the perineum to be covered by the low-profile portion, ensuring flexibility that can follow movements such as opening and closing the legs.

[0054] Horizontal D2 length x of rear low weight part 4Lb b The length x of the rear low basis weight portion 4Lb in the lateral direction D2 is preferably 5 to 30 mm, and more preferably 10 to 20 mm. b The length x may be 5 to 25% of the length (width) in the lateral direction D2 of the absorbent body 4. b In this way, the above-mentioned mound formed by the rise of the rear low basis weight portion 4Lb can be made to have an appropriate size to fit into the gluteal cleft and fit closely. b The length y may be preferably 40 to 80 mm, more preferably 50 to 70 mm. b This allows the above-mentioned ridge formed when worn to be formed with an appropriate length corresponding to the intergluteal cleft, and prevents it from continuing into an area corresponding to a shallow intergluteal cleft or an area where there is no intergluteal cleft.

[0055] Length y in the longitudinal direction D1 of the rear low basis weight portion 4Lb b The horizontal length x b The ratio value (y b / x b ) may be 2 to 8. Depending on the value of this ratio, the above-mentioned mound formed by the rise of the rear low basis weight portion 4Lb can be made to have an appropriate size to fit into the intergluteal cleft and fit closely.

[0056] From the viewpoint of flexible deformation, it is also conceivable to form slits (linear or strip-like gaps that penetrate in the thickness direction) in the absorbent body 4 instead of the low basis weight portion 4L. However, unlike slits, the low basis weight portion 4L ensures the presence of the absorbent body, thereby enhancing the absorption and retention of body fluids, and is therefore preferable.

[0057] From the viewpoint of obtaining flexibility along the longitudinal center line CL from the perineum-facing region M to the intergluteal cleft-facing region B1, it is preferable that the front low weight portion 4Lf and the rear low weight portion 4Lb are continuous as shown in Fig. 4. On the other hand, the front low weight portion 4Lf and the rear low weight portion 4Lb do not have to be continuous as long as the above-mentioned effects of both portions are not hindered, and for example, a medium weight portion 4M may be disposed between the front low weight portion 4Lf and the rear low weight portion 4Lb.

[0058] As shown in FIG. 1, the high basis weight portion 4H is formed in the center of the lateral direction D2 in the bodily fluid outlet facing region C. This is the portion that comes into contact with the bodily fluid outlet (such as the vaginal opening). In the example shown in FIG. 1, the high basis weight portion 4H is surrounded by the front medium basis weight portion 4Mf, but it may also be in contact with the front low basis weight portion 4Lf located at the rear. The high basis weight portion 4H may have a greater thickness than the surrounding front medium basis weight portion 4Mf.

[0059] FIG. 7 shows modified examples of the low basis weight portion 4L. In the examples shown in FIGS. 4 and 5, the front low basis weight portion 4Lf has a rectangular shape in plan view with its long sides in the lateral direction D2, and the rear low basis weight portion 4Lb has a rectangular shape in plan view with its long sides in the longitudinal direction D1. In contrast, in the example shown in FIG. 7(a), the front of the rear low basis weight portion 4Lb gradually widens toward the front, and at the position where it connects with the front low basis weight portion 4Lf, it has a lateral length in the lateral direction D2 equal to the lateral length in the lateral direction D2 of the front low basis weight portion 4Lf. With this shape, the front of the above-mentioned peak formed by the bulge of the rear low basis weight portion 4Lb is wider, making it easier to fit around the start of the gluteal cleft.

[0060] In the example shown in Fig. 7(b), as in the example shown in Fig. 7(a), the front of the rear low basis weight portion 4Lb gradually becomes wider toward the front, providing the same advantages. In the example shown in Fig. 7(b), the contour line is a gentle curve near the boundary between the front low basis weight portion 4Lf and the rear low basis weight portion 4Lb. Furthermore, the front contour line of the front low basis weight portion 4Lf also has a gentle curve at the end in the lateral direction D2. The presence of a curved portion minimizes stress that may be generated due to differences in basis weight.

[0061] <Compression groove> Referring again to Figures 1 to 3, the main body 8 of the absorbent article 1 of this embodiment has compressed grooves (also called fit embossments) formed by compressing at least the top sheet 3 and the absorbent body 4 from the top sheet 3 side. The compressed grooves have the function of absorbing and retaining bodily fluids, and can contribute to preventing the diffusion of bodily fluids or guiding them. In the illustrated example, the compressed grooves may include multiple compressed grooves (denoted by reference numerals 10, 11, 12, and 13). In a plan view, the compressed grooves may be formed in line symmetry with respect to the longitudinal center line CL of the absorbent article 1, but line symmetry is not necessary. The compressed grooves can be formed, for example, by passing a laminate formed by stacking at least the top sheet 3 and the absorbent body 4 between a pair of pressure rolls. In this case, the laminate can be pressed by sandwiching it between the two rolls, with the convex roll positioned on the top sheet 3 side and the flat roll positioned on the absorbent body 4 side. The compression groove may include a low-compression section and a high-compression section compressed at a higher pressure within the low-compression section. In the drawings, the high-compression section is shown in black.

[0062] As shown in FIG. 1 , a pair of central compressed grooves 10, 10 extend along the longitudinal direction D1, primarily from the bodily fluid outlet-facing region C to the perineum-facing region M. The pair of central compressed grooves 10, 10 are spaced apart on both sides of the longitudinal centerline CL so as not to overlap the high basis weight portion 4H. The distance between the pair of central compressed grooves 10, 10 in the lateral direction D2 may be constant or variable. For example, as shown in FIG. 1 , the distance may be small near the boundary between the bodily fluid outlet-facing region C and the perineum-facing region M, then large again thereafter, and gradually decreasing toward the rear end. The pair of central compressed grooves 10, 10 function to prevent leakage outward in the lateral direction D2 from the bodily fluid outlet-facing region C and to guide bodily fluids in the longitudinal direction D1. They also promote deformation, raising the center of the bodily fluid outlet-facing region C in the lateral direction D2 toward the skin.

[0063] A first rear compressed groove 11 is formed behind the pair of central compressed grooves 10, 10 and spaced apart from the pair of central compressed grooves 10, 10. The first rear compressed groove 11 is formed in the buttocks-facing region B, mainly in the intergluteal cleft-facing region B1. The first rear compressed groove 11 is formed across the longitudinal center line CL and has a shape that is convex rearward as a whole. More specifically, the first rear compressed groove 11 may have a shape that includes a horseshoe-shaped compressed groove 11h that has a horseshoe shape (or a U-shape with its ends close together) that overlaps the longitudinal center line CL, and lateral compressed grooves 11s, 11s that branch off from the sides of the horseshoe-shaped compressed groove 11h and extend forward.

[0064] A second rear compressed groove 12 may be formed behind the first rear compressed groove 11 and spaced apart from the first rear compressed groove 11. The second rear compressed groove 12 is a groove extending along the lateral direction D2 and has a rearwardly convex shape. In addition, a front compressed groove 13 is formed in front of the pair of central compressed grooves 10, 10. In the example shown in Figure 1, the front compressed groove 13 has a closed shape formed by combining compressed grooves with different radii of curvature and a forwardly convexly curved shape.

[0065] 1 and 4, the pair of central compressed grooves 10, 10 (their arrangement is shown by dotted lines in FIG. 4) extend into the front low basis weight portion 4Lf and further extend beyond the rear end of the front low basis weight portion 4Lf. In other words, the rear ends 10bt, 10bt of the pair of central compressed grooves 10, 10 are located within the medium basis weight portion 4M, which has a higher basis weight than the low basis weight portion 4L in which the central compressed grooves 10, 10 are primarily arranged.

[0066] On the other hand, when compressed grooves are formed in areas of the absorbent body with a low basis weight, the applied compression force is weaker than in other areas, so sufficient compression may not be achieved, and the compressed grooves may not be formed properly. Furthermore, if the compression at the tips of the compressed grooves is insufficient, the parts that were compressed and joined in the thickness direction may peel off (lift), and the compressed grooves may not be able to perform their function. In contrast, as shown in Figures 1 and 4, if the rear ends 10bt, 10bt of the central compressed grooves 10, 10 are positioned so that they extend rearward beyond the rear end of the front low basis weight portion 4Lf and into the rear medium basis weight portion 4Mb, lifting at the ends of the central compressed grooves 10, 10 can be prevented, and the compressed grooves can function properly.

[0067] The rear ends 10bt, 10bt of the pair of central compressed grooves 10, 10 are formed from the perineum-facing region M to the intergluteal cleft-facing region B1, and when worn, they face the area where the body shape changes from the perineum to the intergluteal cleft. Therefore, the rear ends 10bt, 10bt of the pair of central compressed grooves 10, 10 are easily subjected to force, which can easily cause them to lift. From this perspective, it is preferable that the rear ends 10bt, 10bt of the pair of central compressed grooves 10, 10 be located in the rear center mesh portion 4Mb.

[0068] The rear ends 10bt, 10bt of the pair of central compressed grooves 10, 10 may partially overlap the rear low basis weight portion 4Lb, but from the standpoint of preventing the compressed grooves from floating, it is preferable that they be in contact with the rear low basis weight portion 4Lb (Figure 5) or only partially overlap, if at all.

[0069] <Modifications of absorbent body> FIG. 8 shows an absorbent core 4' according to a modified example. FIG. 8 corresponds to FIG. 4 and shows the absorbent article 1 with the top sheet 3 and side sheets 7, 7 removed. In the example shown in FIG. 8, like the example shown in FIG. 4, the absorbent core 4' has a low basis weight portion 4L, a medium basis weight portion 4M, and a high basis weight portion 4H. However, in this example, a varying basis weight portion 4V is formed between the front low basis weight portion 4Lf and the rear medium basis weight portion 4Mb. The varying basis weight portion 4V is located between the rear end of the front low basis weight portion 4Lf and the front end of the rear medium basis weight portion 4Mb, so that the rear low basis weight portion 4Lb is sandwiched between the varying basis weight portion 4V and the rear low basis weight portion 4Lb in the lateral direction D2. The varying basis weight portion 4V has a basis weight that is higher than the basis weight of the low basis weight portion 4L and lower than the basis weight of the medium basis weight portion 4M. The basis weight of the varying basis weight portion 4V increases gradually or in steps from the front to the rear, that is, as it approaches the rear intermediate basis weight portion 4Mb.

[0070] The formation of the varying basis weight portion 4V prevents abrupt changes in basis weight in the longitudinal direction D1. When the difference between the basis weight of the front low basis weight portion 4Lf and the basis weight of the rear intermediate basis weight portion 4Mb is large, unnecessary stress is generated at the boundary between the front low basis weight portion 4Lf and the rear intermediate basis weight portion 4Mb, preventing the desired deformation of the main body 8 or causing an excessive difference in thickness of the absorbent body 4', leading to discomfort. However, this embodiment prevents such inconveniences. In the planar shape of the low basis weight portion 4L of this embodiment, the total length of the boundary line between the front low basis weight portion 4Lf and the rear intermediate basis weight portion 4Mb is relatively long, sometimes reaching 75 to 95% of the length of the absorbent body 4' in the lateral direction D2, which tends to accentuate the above-mentioned inconveniences. Therefore, when the difference between the basis weight of the front low basis weight portion 4Lf and the basis weight of the rear intermediate basis weight portion 4Mb is large, it is preferable to provide a varying basis weight portion 4V between them.

[0071] Fig. 9 shows an enlarged view of a region including the low basis weight portion 4L in Fig. 8. In the example shown in Fig. 9, the varying basis weight portion 4V is composed of a first portion 4V1 and a second portion 4V2, where the basis weight varies in two stages. However, the varying basis weight portion 4V may be a portion where the basis weight varies in three or four stages, or may be a portion where the basis weight gradually changes as described above.

[0072] Of the first portion 4V1 and the second portion 4V2, the basis weight of the first portion 4V1 arranged adjacent to the front low basis weight portion 4Lf is lower than the basis weight of the second portion 4V2 arranged adjacent to the rear medium basis weight portion 4Mb. v may be 2 to 15 mm, and the length y of the rear low basis weight portion 4Lb in the longitudinal direction D1 b It may be 5 to 20% of the above.

[0073] 9, the pair of central compressed grooves 10, 10 preferably extend over the varying basis weight section 4V. Furthermore, the pair of central compressed grooves 10, 10 preferably extend beyond the rear end of the varying basis weight section 4V to the rear intermediate basis weight section 4Mb. That is, it is preferable that the central compressed grooves 10, 10 extend in the longitudinal direction D1 so as to straddle the varying basis weight section 4V, and that the rear ends 10bt, 10bt of the central compressed grooves 10, 10 are located within the rear intermediate basis weight section 4Mb. As a result, the portions near the rear ends of the central compressed grooves 10, 10 are located in the region where the basis weight changes gradually or in stages from the low basis weight section 4L to the medium basis weight section 4M. As described above, by compressing in areas with a high basis weight, the compressed portion can be formed more reliably, and therefore the portion near the rear end of the central compressed grooves 10, 10 is compressed gradually or in stages, i.e., gradually more reliably and deeply, as it approaches the tip (rear end) 10bt, 10bt, which prevents peeling (lifting) near the rear end and also prevents any discomfort when touching the compressed grooves.

[0074] <Method of manufacturing absorbent body> Next, a method for manufacturing the absorbent body 4 will be described. FIG. 10 schematically shows a manufacturing apparatus 60 for manufacturing the absorbent body 4. In such an apparatus, an absorbent material to be used as the absorbent body is supplied, stacked in an absorbent body mold having a plurality of suction holes on the bottom surface, and then demolded to obtain the absorbent body 4. As shown in FIG. 10, a pulp supply unit 61 that supplies a fibrous material mainly containing pulp is provided upstream of the manufacturing apparatus 60. The pulp supply unit 61 may be equipped with a defibrator, which defibrates a pulp sheet or the like and supplies the pulp to a duct 62. A polymer particle introduction unit 63 for supplying superabsorbent polymer particles may be provided midway through the duct 62. Thus, the pulp and superabsorbent polymer particles are mixed in the duct 62, and the resulting mixed absorbent material is supplied to a stacking drum 65.

[0075] A plurality of absorbent molds 50 are arranged on the outer peripheral surface of the fiber stacking drum 65, spaced apart in the circumferential direction. As the fiber stacking drum 65 rotates, the absorbent molds 50, 50, ... can sequentially receive absorbent material. The bottom surface of the absorbent mold 50 is made of a perforated plate or mesh plate, and by sucking gas through the holes, the absorbent material can be accumulated on the bottom surface of the absorbent mold 50. Furthermore, by exhausting gas through the holes, the absorbent 4 can be supplied to a transport means 66 such as a belt conveyor. A negative pressure chamber and a positive pressure chamber are provided inside the fiber stacking drum 65, and each chamber can suck in and exhaust gas, respectively.

[0076] A scuffing roll (or brush) 64 may be provided downstream in the duct 62. The scuffing roll 64 can scrape off excess accumulated absorbent material and make the surface of the absorbent material accumulated in the absorbent mold 50 uniform.

[0077] The absorbent body 4 supplied to the conveying means 66 can be compressed in the thickness direction by compression means 67. The compression means 67 may be a pair of rolls as shown in Figure 10, or a pair of pressing members that approach the absorbent body 4 from both sides. The compression means 67 improves the shape retention of the absorbent body 4.

[0078] FIG. 11 shows a plan view of an example of an absorbent body mold 50 provided on the fiber stacking drum 65. FIG. 12(a) shows an enlarged view of portion P1 of FIG. 11, and FIG. 12(b) shows an enlarged view of portion P2 of FIG. 11. FIG. 13(a) shows a Y1-Y1 cross section of FIG. 11, and FIG. 13(b) shows a Y2-Y2 cross section of FIG. 11. The absorbent body mold 50 shown in FIGS. 11 to 13 is a mold used to manufacture the above-mentioned absorbent body 4 (FIGS. 1 to 5). The longitudinal direction of the absorbent body mold 50 corresponds to the longitudinal direction D1 of the absorbent body 4 to be obtained, and the lateral direction of the absorbent body mold 50 corresponds to the lateral direction D2 of the absorbent body 4, so in the drawings, the longitudinal direction and lateral direction of the absorbent body mold 50 are also indicated by the symbols D1 and D2, respectively.

[0079] As shown in Figures 11 and 13, the absorbent mold 50 has an overall concave shape so that absorbent material can be accumulated. In this example, the bottom surface of the absorbent mold 50 is a perforated plate, i.e., a large number of openings 55, 55, ... are formed on the bottom surface of the absorbent mold 50 (Figure 12). The shape of the openings is not uniform throughout the absorbent mold 50, and the opening area ratio, i.e., the ratio of the total area of ​​openings per unit area of ​​the bottom surface, varies depending on the location. More specifically, the bottom surface of the absorbent mold 50 has a low accumulation zone Z where the opening area ratio is low. L and the low concentration zone Z of the hole L The front middle accumulation zone Z has a higher open area ratio than the open area ratio in Mf and rear middle accumulation zone Z Mb (Together, medium accumulation zone Z M The anterior middle accumulation zone Z Mf and rear middle accumulation zone Z MbThe open area ratio and configuration of the absorbent mold 50 may be the same or different, but it is preferable that they are the same because this reduces the complexity of manufacturing the absorbent mold 50. The bottom surface of the absorbent mold 50 may be formed from a mesh plate made of combined wires.

[0080] Low concentration zone Z L , forward middle accumulation zone Z Mf , and the rear middle accumulation zone Z Mb are zones corresponding to the front low basis weight portion 4Lf, the front medium basis weight portion 4Mf, and the rear medium basis weight portion 4Mb of the absorbent body 4 (FIG. 4, etc.). Mf The front middle accumulation zone Z has a recess 51 formed therein (FIG. 13), and this recess 51 corresponds to the high basis weight portion 4H (FIG. 4, etc.) of the absorbent body 4. Mf When the recess 51 is formed in the front middle accumulation zone Z, the open area ratio of the bottom surface of the recess 51 may be the same as or different from the open area ratio of the surrounding area. Mf In this case, by increasing the open area ratio of the bottom surface of the recess 51, the amount of absorbent material accumulated in the recess 51 can be further increased. This configuration is suitable when it is desired to further increase the basis weight of the high basis weight portion 4H and increase the basis weight difference between the high basis weight portion 4H and the front middle basis weight portion 4Mf. L A non-perforated convex member 52 is provided inside the absorbent body 4, and this non-perforated convex member 52 corresponds to the rear low basis weight portion 4Lb of the absorbent body 4.

[0081] As shown in Figures 12(a) and (b), the shape of one opening 55 on the bottom surface of the absorbent mold 50 is square in plan view. However, the shape of the opening 55 is not limited to that shown in the figures, and may be a rectangle other than a square, a polygon other than a square, a circle, an ellipse, or the like. In this example, the front middle accumulation zone Z Mf (Medium Accumulation Zone Z M The shape and area of ​​one opening 55 in the low concentration zone Z L The shape and area of ​​one opening 55 in the low-accumulation zone Z L and the front middle accumulation zone Z Mf(Medium Accumulation Zone Z M The difference in the open area ratio between the intermediate concentration zone Z and the intermediate concentration zone Z is the difference in the density or closeness of the open holes 55. M The open area ratio of the low concentration zone Z L If the open area ratio is larger than the above, it is considered to be the medium accumulation zone Z. M The shape and area of ​​the opening 55 formed on the bottom surface of the low concentration zone Z L The shape and area of ​​the openings 55 formed on the bottom surface of the absorbent mold 50 may be different from those of the openings 55 formed on the bottom surface of the absorbent mold 50. However, if the shape and area of ​​each opening are the same overall, this is preferable because it reduces the complexity of manufacturing the absorbent mold 50.

[0082] In addition, the medium accumulation zone Z M (Front middle accumulation zone Z Mf and rear middle accumulation zone Z Mb The open area ratio of the low concentration zone Z may be 25 to 50%. L The open pore area ratio may be 5 to 20%.

[0083] In the absorbent body mold 50 used in this embodiment, a low concentration zone Z is a region corresponding to the front low basis weight portion 4Lf of the absorbent body 4 (FIG. 4, etc.). L The open area ratio of the bottom surface of the medium concentration zone Z MThe open area ratio of the bottom surface of the front low basis weight portion 4Lf is smaller than the open area ratio of the bottom surface. In other words, the low basis weight of the front low basis weight portion 4Lf is achieved by reducing the open area ratio of the bottom surface. Here, to form regions with different basis weights depending on the location within the absorbent body 4, one method is to vary the bottom surface level (bottom height) by partially forming unevenness on the bottom surface of the absorbent body mold, thereby reducing the thickness of the accumulated absorbent material. While such a method can ensure differences in basis weight, varying the bottom surface level creates steps between the regions, and when attempting to form a wide-area low basis weight portion, the absorbent body material is likely to be separated at the edges of the steps. Therefore, during the manufacturing process of the absorbent body 4, for example, during the material scraping process using the scuffing roll 64, the absorbent body is likely to become discontinuous at the steps, which may result in the absorbent body 4 being torn or not achieving the desired thickness. In particular, the front low basis weight portion 4Lf (Figs. 4 and 5, etc.) is a portion that is relatively long in the horizontal direction D2 and has a relatively long boundary line with the medium basis weight portion 4M, so that it is prone to tearing due to steps. In contrast, in this embodiment, as shown in Figs. 11 and 13, the open area ratio of the bottom surface is made different from that of the surrounding area to obtain a low basis weight for the front low basis weight portion 4Lf, and the low concentration zone Z L and intermediate accumulation zone Z M There is no step at the boundary between the front low basis weight portion 4Lf and the middle basis weight portion 4M (the bottom surface level is the same), so that problems such as tearing that may occur between the front low basis weight portion 4Lf and the middle basis weight portion 4M can be prevented.

[0084] On the other hand, as described above, a non-perforated convex member 52 is provided in the region corresponding to the rear low basis weight portion 4Lb (FIGS. 11 and 13). The presence of the non-perforated convex member 52 reduces the thickness of the absorbent material accumulated by that amount, thereby ensuring a low basis weight. In this way, the low basis weight of the rear low basis weight portion 4Lb is achieved by changing the bottom level (bottom height), unlike the front low basis weight portion 4Lf described above. In the case of the rear low basis weight portion 4Lb, which has a short length in the lateral direction D2 (narrow width) and a small area, it is preferable to use the non-perforated convex member 52 as described above, rather than reducing the open hole area ratio. The reasons for this are as follows: When two regions with different open area ratios are adjacent to each other, fibrous material such as pulp accumulates across the boundary during stacking, so the boundary between the two regions is not very clear. Therefore, if an attempt were made to form a low basis weight by reducing the open area ratio of the bottom surface in the region corresponding to the rear low basis weight portion 4Lb instead of using the non-perforated convex member 52, the boundary between the rear low basis weight portion 4Lb and the rear medium basis weight portion 4Mb surrounding it would become unclear, and there is a possibility that the narrow region for the rear low basis weight portion 4Lb would not be secured. In contrast, according to this embodiment, which uses the non-perforated convex member 52, the thickness of the accumulated absorbent material can be reduced and the accumulated amount can be reliably reduced, so the low basis weight region can be secured more reliably.

[0085] In this manner, in this embodiment, the front low basis weight portion and the rear low basis weight portion are formed by different means according to the shape of each low basis weight portion, so that the area of ​​the low basis weight portion can be reliably secured without problems such as tearing of the absorbent body.

[0086] <Modification of absorbent type> 14 to 16 show an absorbent body mold 50' according to a modification. FIG. 14 is a plan view of the absorbent body mold 50' and corresponds to FIG. 11. FIG. 15 shows an enlarged view of portion P3 of FIG. 14. FIG. 16(a) shows a Y1'-Y1' cross section of FIG. 14, and FIG. 16(b) shows a Y2'-Y2' cross section of FIG. 14. The absorbent body mold 50' shown in FIGS. 14 to 16 is a mold used to manufacture a modification (FIGS. 1 to 5) of the absorbent body 4' described above.

[0087] The basic structure of the absorbent mold 50' is the same as that of the absorbent mold 50 shown in Figures 11 to 13. The absorbent mold 50' has a concave shape as a whole so that absorbent material can be accumulated, and the bottom surface of the absorbent mold 50' is also formed from a perforated plate. The bottom surface of the absorbent mold 50' has a low accumulation zone Z with a low open area ratio, similar to the absorbent mold 50 (Figures 11 to 13). L and the low concentration zone Z of the hole L The front middle accumulation zone Z has an area ratio higher than the open area ratio in Mf and rear middle accumulation zone Z Mb (Medium Accumulation Zone Z M However, in the absorbent type 50', the low concentration zone Z L and rear middle accumulation zone Z Mb Between the change accumulation zone Z V The change accumulation zone Z V is the area corresponding to the above-mentioned basis weight changing portion 4V. V is the low concentration zone Z L Higher open area ratio and rear middle accumulation zone Z Mb The lower the open area ratio and the lower the concentration zone Z L From rear middle accumulation zone Z Mb This is a zone in which the open pore area ratio increases gradually or in stages as the temperature approaches the upper limit.

[0088] FIG. 15 shows the portion P3 of FIG. 14, i.e., the low accumulation zone Z L , change accumulation zone Z V , and the rear middle accumulation zone Z Mb 15 is an enlarged view of the area spanning the absorbent mold 50'. In the absorbent mold 50', the shape and area of ​​the openings 55, 55, ... included in each zone are the same, and the difference in the opening area ratio is obtained by the difference in the density or closeness of the openings 55, 55, .... As shown in FIG. 15, the change accumulation zone Z V is the low concentration zone Z L Zone 1 Z adjacent to V1 and rear middle accumulation zone Z Mb Zone 2 Z adjacent to V2 Zone 1 Z V1The open area ratio in the second zone Z V2 The open area ratio is smaller than that of the first zone Z. V1 corresponds to the first part 4V1 of the absorber 4' (see FIG. 9, etc.), and the second zone Z V2 corresponds to the second part 4V2 (FIG. 9, etc.). In the illustrated example, the change accumulation zone Z V The open area ratio is the ratio of the first zone Z along the longitudinal direction of the absorbent body mold 50'. V1 and Zone 2 Z V2 The change accumulation zone Z V The open area ratio in the longitudinal direction D1 may be gradually changed.

[0089] In this way, in order to form the front low basis weight portion 4Lf, the low concentration zone Z L and rear middle accumulation zone Z Mb The open area ratio changes longitudinally between the change accumulation zone Z V By providing a low concentration zone Z L From rear middle accumulation zone Z Mb Since the accumulated amount of absorbent material can be gradually changed over the entire length, a sudden change in basis weight can be prevented midway through the absorbent body, and continuity between the front low basis weight portion 4Lf and the rear intermediate basis weight portion 4Mb is improved. Therefore, when there is a large difference in basis weight between the front low basis weight portion 4Lf and the rear intermediate basis weight portion 4Mb, it is possible to prevent discontinuity in the absorbent body.

[0090] Furthermore, one aspect of the present invention may be a method for manufacturing an absorbent article using an absorbent body manufactured by the above-described manufacturing method.

[0091] <Relationship between absorbent articles and individual packaging> Below, we will also explain the folding positions when individually packaging the absorbent article of this embodiment with a packaging sheet. When obtaining an individually packaged absorbent article (individually packaged absorbent article), the absorbent article is placed on the inner surface of the packaging sheet, and both the absorbent article and the packaging sheet are folded inward (toward the top sheet) in the longitudinal direction at least in thirds. Fig. 17 shows the absorbent article 1 shown in Fig. 1 placed on the packaging sheet 20. Fig. 18 also shows a schematic cross section taken along line III-III in Fig. 17. Fig. 19 shows the individually packaged absorbent article 100 obtained by folding the absorbent article 1 and packaging sheet 20 from the state shown in Fig. 18.

[0092] As shown in FIG. 17 , the absorbent article 1 and the packaging sheet 20 are folded along three fold lines (FL1, FL2, and FL3) extending along the lateral direction D2. That is, they are folded in four. When folding, the end of the absorbent article 1 is folded back along a third fold line FL3 near the boundary between the front buttocks-facing region (gluteal cleft-facing region) B1 and the rear buttocks-facing region B2, and then the rear portion is folded back along a second fold line FL2 passing through the perineum-facing region M. Furthermore, the front portion is folded back along a first fold line FL1 near the boundary between the front region F and the bodily fluid outlet-facing region C. Note that the fastening tape 22 is positioned after the absorbent article 1 is folded and packaged together with the packaging sheet 20, but is also shown in FIGS. 17 and 18 to indicate the position of the fastening tape 22.

[0093] The schematic diagrams of Figures 18 and 19 also show the positions of the front middle basis weight portion 4Mf, the high basis weight portion 4H, the front low basis weight portion 4Lf, the rear low basis weight portion 4Lb, and the rear middle basis weight portion 4Mb. Although the basis weight height is not necessarily reflected in the thickness depending on the process after absorbent body production, the schematic diagrams of Figures 18 and 19 reflect the basis weight in the thickness. As shown in Figure 18, in this embodiment, the fold line is positioned to avoid the high basis weight portion 4H, making the folding process easier. Furthermore, the ease of folding is further improved by arranging the second fold line FL2 to pass through the front low basis weight portion 4Lf and the third fold line FL3 to pass through the rear low basis weight portion 4Lb.

[0094] 19, in the individually packaged absorbent article 100, the fastening tape 22 overlaps the front low basis weight portion 4Lf, not the region including the rear low basis weight portion 4Lb and the rear middle basis weight portion 4Mb. The low basis weight portion 4Lb can be a depression in the center in the lateral direction D2, which may make it difficult for the fastening tape 22, which is also located in the center in the lateral direction D2, to adhere. In contrast, according to this embodiment, the fastening tape 22 can be more reliably adhered by overlapping the front low basis weight portion 4Lf, which has a uniform basis weight across the lateral direction D2.

[0095] Although the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments. Furthermore, the above embodiments can be variously changed, modified, substituted, added, deleted, and combined within the scope of the claims, and these also fall within the technical scope of the present invention. [Explanation of symbols]

[0096] 1. Absorbent articles (sanitary napkins) 2 Back Seat 3 Topsheet 4, 4' absorber 4H High absorbent area 4L Low basis weight of absorbent body 4Lb Rear low weight section (slim low weight section) 4Lf Front low weight part 4M Medium weight of absorbent body 4Mb Rear middle area 4Mf Front center area 4V Weight change part 4V1 Part 1 4V2 Part 2 7 Side seats 8. Main body (absorbent article main body) 10 Central compression groove 10bt Rear end of central compression groove 11 First rear compression groove 11h Horseshoe-shaped compression groove 11s Lateral compression groove 12 Second rear compression groove 13 Front compression groove 20 Packaging Sheet 22 Fastening tape 50, 50' absorbent type 51 Recess 52 Non-perforated convex parts 55 Open hole 60 Absorbent manufacturing equipment 61 Pulp supply section 62 Duct 63 Polymer particle introduction section 64 Scuffing Roll 65 Fiber drum 66 Transportation 67 Compression Method B Area opposite the buttocks B1 Anterior buttock opposing area (gluteal cleft opposing area) B2 Posterior buttock opposing area C Area facing body fluid outlet CL longitudinal centerline D1 Longitudinal direction D2 Lateral direction F Anterior area FL1, FL2, FL3 fold lines HF Hip Hold Flap M Middle area (opposite perineum area) WF Wing Flap Z Mf Front intermediate accumulation zone Z Mb Rear middle accumulation zone Z L Low concentration zone Z V Change Accumulation Zone

Claims

1. An elongated absorbent article comprising a skin-side top sheet, a non-skin-side back sheet, and an absorbent body disposed between the top sheet and the back sheet, the absorbent body has a medium basis weight portion and a low basis weight portion adjacent to the medium basis weight portion and having a basis weight lower than that of the medium basis weight portion, The low basis weight portion includes a front low basis weight portion and a rear low basis weight portion having a width shorter than that of the front low basis weight portion, The longitudinal length of the front low basis weight portion is 40 to 120% of the lateral length of the absorbent body, the intermediate basis weight portion includes a front intermediate basis weight portion adjacent to the front low basis weight portion on the front side, and a rear intermediate basis weight portion adjacent to the rear of the front low basis weight portion and adjacent to both sides and rear of the rear low basis weight portion, a varying basis weight portion is formed between the front low basis weight portion and the rear intermediate basis weight portion, At least the top sheet and the absorbent body are formed with compressed grooves recessed from the top sheet side to the back sheet side, and the compressed grooves include a pair of central compressed grooves extending along the longitudinal direction of a body fluid discharge outlet facing region that faces the body fluid discharge outlet of the wearer when worn, The absorbent article, wherein the pair of central compressed grooves extend rearward beyond the rear end of the front low basis weight portion and onto the varying basis weight portion.

2. The absorbent article according to claim 1 , wherein the lateral length of the front low basis weight portion is equal to the lateral length of the absorbent body.

3. 3. The absorbent article according to claim 1, wherein the lateral length of the rear low basis weight portion is 5 to 25% of the lateral length of the absorbent body.

4. 3. The absorbent article according to claim 1, wherein the basis weight in the varying basis weight portion is higher than the basis weight of the front low basis weight portion, lower than the basis weight of the rear intermediate basis weight portion, and gradually or stepwise increases toward the rear.

5. 5. The absorbent article according to claim 4, wherein the absorber further has a high basis weight portion, surrounded by the front middle basis weight portion and having a basis weight higher than that of the front middle basis weight portion, in a region facing the body fluid discharge outlet that faces the body fluid discharge outlet of the wearer when worn.

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