JP7724706B2 - absorbent articles - Google Patents

Description

The present invention relates to an absorbent article that is worn in the crotch area and used to absorb body exudates.

Among known absorbent articles for women, such as sanitary napkins, are those that include an absorbent core that absorbs and retains menstrual blood and other body waste, and flaps that extend outward from the outer edge of the absorbent core and form the contours of the absorbent article (Patent Documents 1 to 4).

The absorbent articles described in Patent Documents 1 to 3 have wing portions, including a vertical center portion, of the portions of the flap portion located on both sides of the absorbent body (side flap portions), which extend laterally outward more than the peripheral portions. The "vertical direction" referred to here corresponds to the front-to-back direction of the wearer of the absorbent article, and the "lateral direction" refers to a direction perpendicular to the vertical direction. The wing portions are used by manually folding them over with the fingers toward the non-skin-facing surface (outer surface) of the crotch portion when fastening the absorbent article to the skin-facing surface (inner surface) of the crotch portion of clothing such as shorts, and a fastening portion is arranged on the surface facing the non-skin-facing surface of the crotch portion of the clothing when folded over . On the other hand, the absorbent article described in Patent Document 4 has a relatively short outward extension length of the side flap portion, and does not have a fastening portion arranged on the side flap portion. When worn, the side flap portion is not folded back onto the non-skin-facing side of the garment, but extends downward along the wearer's legs ([0058] of Patent Document 4).

In the absorbent article described in Patent Document 2, the portions of the side flap portions located longitudinally rearward of the wing portions extend laterally outward to the same extent as the wing portions to form hip hold portions. Patent Document 2 also describes devising the outer contour (outline) of the hip hold portion to ensure a good fit along the shape of the wearer's buttocks and to prevent the hip hold portion from turning up. Furthermore, the absorbent article described in Patent Document 3 has, as shown in Figure 1, two contour lines that start at the rear end of the absorbent article and extend diagonally longitudinally forward and laterally outward, each of which has two convex portions, and two inwardly curved portions between the longitudinally forward convex portion and the rear end of the absorbent article.

Japanese Patent Application Laid-Open No. 2020-5845 Japanese Patent Application Laid-Open No. 2018-29842 Japanese Patent Application Laid-Open No. 2020-146089 International Publication No. 2019/26176

Making the side flap portions of the rear region of an absorbent article wider by extending them laterally outward from the surrounding areas, as in the hip hold portion described in Patent Document 2, is effective in preventing rearward leakage of body waste, but it can also cause strong discomfort to the wearer, particularly around the buttocks. The rear region of an absorbent article corresponds to the wearer's buttocks and is prone to receiving relatively large external forces, such as when the wearer walks. If the rear region is made wider, it becomes less likely to deform when subjected to external forces, reducing the rear region's ability to conform to the wearer's body, potentially causing discomfort to the wearer (a feeling that the absorbent article is not responding to bodily movements). Furthermore, if the apex of the inwardly convex curved portion near the rear end of the hip hold portion H shown in Figure 1 of the same document is located further rearward in the front-to-rear direction than the rear end of the absorber 4, the inwardly convex curved portion is likely to crease or bend, causing discomfort to the wearer.

Furthermore, in the absorbent article of Patent Document 3, multiple inwardly curved portions are formed between the rear end and the convex portion located in the rear region, and therefore the convex portion interposed between two adjacent inwardly curved portions is susceptible to the influence of external forces caused by the wearer's body movements. As a result, the ability of the inwardly curved portions to follow external forces described above is reduced, and kinks and folds in the inwardly curved portions can occur frequently.

There has yet to be an absorbent article that is highly leak-proof, making it difficult for body waste to leak, and that flexibly deforms when the wearer walks, causing no discomfort to the wearer.

The objective of the present invention is to provide an absorbent article that is leak-proof and comfortable to wear.

The present invention provides an absorbent article that includes an absorbent body capable of absorbing and retaining bodily fluids, has a vertical direction corresponding to the front-to-back direction of the wearer, and a horizontal direction perpendicular to the vertical direction, and has an excretory part-facing region that is positioned opposite the wearer's excretory part when worn, a front region that is positioned forward in the vertical direction from the excretory part-facing region, and a rear region that is positioned rearward in the vertical direction from the excretory part-facing region.
One embodiment of the absorbent article of the present invention comprises a flap portion extending outward from the outer edge of the absorbent body and forming the outline of the absorbent article, the flap portion comprising a pair of side flap portions located laterally outward of a pair of imaginary straight lines extending in the vertical direction through the outermost lateral end of the absorbent body, and the absorbent body being located laterally inside the side flap portions.
In one embodiment of the absorbent article of the present invention, the outer edges of the pair of side flap portions have a pair of rear convex portions in the rear region that are located forward in the vertical direction from the rear end of the flap portions and protrude outward in the horizontal direction beyond the peripheral portion.
In one embodiment of the absorbent article of the present invention, the portion of the outer edge of the flap portion sandwiched between the longitudinal rear end of the flap portion and the rear convex portion has an inward convex curved portion having a center of curvature outside the outer edge.
In one embodiment of the absorbent article of the present invention, the inward convex curved portion has a single curved shape consisting of curved lines extending from the longitudinal rear end of the flap portion and the rear convex portion as starting points toward a single convex apex located between the two starting points, and the apex is located longitudinally forward of the longitudinal rear end of the absorbent body.

The present invention provides an absorbent article that is leak-proof and comfortable to wear.

FIG. 1 is a schematic plan view of the skin-facing side of a sanitary napkin, which is one embodiment of the absorbent article of the present invention. FIG. 2 is a schematic cross-sectional view taken along line II in FIG. 1 (a cross-section taken along the thickness and lateral directions of the sanitary napkin). FIG. 3 is a schematic plan view of the skin-facing side of the rear region of the sanitary napkin shown in FIG. 4(a) to 4(c) are explanatory diagrams of a method for measuring the torsional torque value. FIG. 5 is an enlarged view of a portion of FIG. FIG. 6 is a schematic cross-sectional view of the sanitary napkin shown in FIG. 1 taken along the thickness direction and the width direction when worn. 7(a) and 7(b) are schematic plan views of the skin-facing side of sanitary napkins of Experimental Examples 2 and 3. FIG. 8(a) to 8(c) are schematic plan views of the skin-facing side of the sanitary napkins of Experimental Examples 4 to 6. FIG.

The present invention will now be described based on preferred embodiments with reference to the drawings. Note that in the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. The drawings are essentially schematic, and the proportions of each dimension may differ from those of the actual product.

1 to 3 show a sanitary napkin 1 (hereinafter also referred to as "napkin 1"), which is one embodiment of the absorbent article of the present invention. Napkin 1 has a longitudinal direction X, which corresponds to the front-to-back direction of a wearer and extends from the front side (belly side) of the wearer through the crotch region to the rear side (dorsal side), and a transverse direction Y, which is perpendicular to longitudinal direction X.
In the present invention, "vertically forward" refers to a position that is longitudinally forward of a reference position (toward the wearer's ventral side), and "vertically rear" refers to a position that is longitudinally rearward of a reference position (toward the wearer's back side).

In this embodiment, the napkin 1 is elongated in the vertical direction X as shown in FIG.
In this embodiment, the napkin 1 is formed symmetrically on one side and the other side with respect to the horizontal center line CLy. The horizontal center line CLy is an imaginary line extending in the vertical direction X, dividing the napkin 1 in the unfolded state as shown in Figure 1 into two equal parts in the horizontal direction Y.

The napkin 1 comprises an absorbent body 4 capable of absorbing and retaining bodily fluids (menstrual blood, urine, feces, sweat, etc.). In addition, the napkin 1 preferably further comprises a liquid-permeable top sheet 2 that can come into contact with the wearer's skin, and a leak-proof back sheet 3. In this case, the absorbent body 4 is disposed between the top sheet 2 and the back sheet 3, as shown in FIG. 2. In the napkin 1, the top sheet 2 covers the entire skin-facing side of the absorbent body 4, and the back sheet 3 covers the entire non-skin-facing side of the absorbent body 4. Both sheets 2 and 3 can be made of any material commonly used in this type of absorbent article, without any particular restrictions. The top sheet 2 can be made of any liquid-permeable sheet, including, for example, nonwoven fabric, woven fabric, and paper. The backsheet 3 can be a leak-proof sheet, specifically a liquid-impermeable sheet (one that does not allow liquid to pass through at all) or a sheet that is poorly liquid-permeable (one that does not quite allow liquid to pass through, but does not). Examples include a moisture-permeable resin film and a laminate of such a resin film and nonwoven fabric.

In this embodiment, as shown in FIG. 1, a pair of side sheets 5, 5 are arranged on both sides of the skin-facing surface of the napkin 1 (the skin-facing surface of the topsheet 2) along the longitudinal direction X. The pair of side sheets 5, 5 are arranged over substantially the entire length of the longitudinal direction X so as to overlap both sides of the absorbent body 4 along the longitudinal direction X in a plan view. As shown in FIG. 2, of both sides of the side sheet 5 along the longitudinal direction X, the outer portions including the outer edges located on the outer sides in the lateral direction Y are fixed to another member (the backsheet 3 in the illustrated embodiment) to form fixed edges, while the inner portions including the inner edges located on the inner sides in the lateral direction Y are free edges that are not fixed to other members. When the napkin 1 is worn, the free edges of the side sheets 5 rise toward the wearer's skin, thereby preventing the outflow of exudates such as menstrual blood outward in the lateral direction Y. The side sheets 5 can be made of a sheet with the same leak-proof properties as the backsheet 3.

In the present invention, the "skin-facing side" refers to the side of the absorbent article or its constituent member (e.g., absorbent core 4) that faces the wearer's skin when the absorbent article is worn, i.e., the outer surface that is relatively closer to the wearer's skin. The "non-skin-facing side" refers to the outer surface of the absorbent article or its constituent member that faces the opposite side from the skin when the absorbent article is worn, i.e., the outer surface that faces relatively farther from the wearer's skin. Note that "when worn" here refers to the normal, appropriate wearing position, i.e., a state in which the correct wearing position of the absorbent article is maintained.

As shown in Figure 1, the napkin 1 has an excretory area-facing region M that faces the wearer's excretory area, a front region F that is located forward (toward the ventral side) of the excretory area-facing region M in the longitudinal direction X, and a rear region R that is located behind (toward the back) of the excretory area-facing region M in the longitudinal direction X.

In the present invention, the "excretory part-facing region" refers to a region of the absorbent article's absorber-disposed region (region overlapping the absorber in a planar view) that includes a region facing the excretory part and that faces the excretory part. The "excretory part" refers to the site where the wearer of the absorbent article excretes bodily fluids (menstrual blood, urine, feces, sweat, etc.), and is typically the vaginal opening, penis, or anus, depending on the intended use of the absorbent article. The "excretory part-facing region" refers to a region of the absorbent article that overlaps the excretory part in a planar view when worn. The excretory part-facing region can be, for example, the entire region of the absorbent article's absorber-disposed region that is aligned vertically with the excretory part-facing region (the region that overlaps with the horizontal projection of the excretory part-facing region). When the absorbent article is a feminine absorbent article such as a sanitary napkin 1 or a panty liner, the excretory part-facing region refers to a region that faces the vaginal opening when worn.

The boundary between the front region F and the excretory area-facing region M (the front end of the excretory area-facing region M in the longitudinal direction X) is typically located rearward of the front longitudinal end 1F of the napkin 1 in the longitudinal direction X, at a distance of 10 to 40% of the total length of the napkin 1 in the longitudinal direction X. Furthermore, the boundary between the rear region R and the excretory area-facing region M (the rear end of the excretory area-facing region M in the longitudinal direction X) is typically located forward of the rear longitudinal end 1R of the napkin 1 in the longitudinal direction X, at a distance of 10 to 40% of the total length of the napkin 1 in the longitudinal direction X. Here, "the total length of the napkin 1 in the longitudinal direction X" refers to the length along the longitudinal direction X between the front longitudinal end 1F and the rear longitudinal end 1R of the napkin 1 in its natural state (when no external force is applied).

The absorbent body 4 includes at least an absorbent core 40. In this embodiment, the absorbent core 40 has a shape that is elongated in the longitudinal direction X in a plan view, and its longitudinal direction coincides with the longitudinal direction X of the napkin 1.
The absorbent core 40 constitutes the main body of the absorbent body 4 and contains a water-absorbent material that enables it to absorb and retain body fluids. Examples of the water-absorbent material include water-absorbent fibers and water-absorbent polymers, and these may be used alone or in combination. Examples of the water-absorbent fibers include natural fibers such as wood pulp and hydrophilic fibers such as hydrophilic synthetic fibers. Examples of the water-absorbent polymers that may be used include those conventionally used in this type of absorbent body, without particular limitation, and examples thereof include polymers or copolymers of acrylic acid or alkali metal acrylates.
The absorbent core 40 may be of either a stacked fiber type or a sheet type. The stacked fiber type absorbent core typically comprises an aggregate of fibrous materials such as absorbent fibers, with absorbent polymer particles optionally supported on the aggregate. The stacked fiber type absorbent core can be manufactured by a conventional method using a known stacking device equipped with a rotating drum. On the other hand, the sheet type absorbent core typically comprises a fiber sheet having absorbent polymer particles fixed to the interior or surface thereof, and is also referred to as an absorbent sheet. Examples of the fiber sheet include paper and nonwoven fabric. The sheet type absorbent core is thinner and more flexible than the stacked fiber type absorbent core. The sheet type absorbent core may, for example, comprise two opposing fiber sheets with absorbent polymer particles interposed between them.

In this embodiment, as shown in FIG. 2, the absorbent body 4 includes, in addition to the absorbent core 40, a liquid-permeable core wrap sheet 41 that covers the outer surfaces (skin-facing surface and non-skin-facing surface) of the absorbent core 40. The core wrap sheet 41 is used for purposes such as improving the shape retention of the absorbent core 40 and preventing the materials that make up the absorbent core 40, such as water-absorbent polymer particles, from falling off, and is typically made of paper, water-permeable nonwoven fabric, or the like. The core wrap sheet 41 may consist of only one sheet, or may be made up of multiple sheets. The absorbent core 40 and the core wrap sheet 41 may be bonded together with an adhesive, such as a hot-melt adhesive.

In this embodiment, as shown in FIG. 2, the absorbent body 4 has a fiber agglomerate layer 42 in the excretory-facing region M, which is mainly made of fiber agglomerates 11 containing non-absorbent fibers. The fiber agglomerate layer 42 is covered, together with the absorbent core 40, by a core wrap sheet 41. In this embodiment, the fiber agglomerate layer 42 is disposed only over the entire excretory-facing region M, and the region in which the fiber agglomerate layer 42 is disposed is the excretory-facing region M. Regions in the absorbent body 4 where the fiber agglomerate layer 42 is not disposed (portions located in the front region F and rear region R of the absorbent body 4) include an absorbent core 40 but no fiber agglomerate layer 42. Therefore, the region in which the fiber agglomerate layer 42 is disposed is thicker and bulkier than the region in which the fiber agglomerate layer 42 is not disposed. Due to the difference in thickness of the absorbent body 4 resulting from the presence or absence of the fiber agglomeration layer 42, the excretion part-facing region M, where the fiber agglomeration layer 42 is located, is raised on the skin-facing side compared to the front region F and rear region R, where the fiber agglomeration layer 42 is not located, forming a so-called raised center.

The fiber agglomeration layer 42 is present in the region (inter-constricted region) located between the rear constricted region 62 and the front constricted region 61 (described below) in the longitudinal direction X. Due to the presence of the fiber agglomeration layer 42, the inter-constricted region has higher compression recovery than the region adjacent to the inter-constricted region in the longitudinal direction X. The fiber agglomeration layer 42 will be described in more detail later.

1, the napkin 1 includes flap portions 6 that extend outward from the outer edge (periphery) of the absorbent body 4 and form the outline of the napkin 1. The flap portions 6 are areas where the absorbent body 4 is not placed.
In this embodiment, the flap portion 6 is composed of members arranged so as to straddle the outer edge of the absorbent body 4 from the inside to the outside, and in the illustrated embodiment, is composed of one or more of the topsheet 2, the backsheet 3, and the sidesheet 5. The multiple members constituting the flap portion 6 are joined to each other by a joining means such as adhesive, thermal or ultrasonic fusion. In this embodiment, an end seal portion 60 is formed by fusion-bonding the outer edge of the flap portion 6 (the outer edge of the flap portion 6 and its vicinity) all around.

The flap portion 6 is composed of a pair of side flap portions 6S, 6S located outward from the reference in the horizontal direction Y of a pair of imaginary straight lines VL, VL that pass through the outermost end of the absorbent body 4 in the horizontal direction Y and extend in the vertical direction X, a front flap portion 6F located inward from the reference in the horizontal direction Y and in a front region F, and a rear flap portion 6R located inward from the reference in the horizontal direction Y and in a rear region R.
The "laterally outermost end of the absorbent body" is the part located furthest outward in the lateral direction Y on each of the lateral sides Y of the absorbent body 4, and in this embodiment, it is a pair of side edges 4S, 4S along the longitudinal direction of the absorbent body 4.
The side flap portions 6S are required to be positioned outward in the lateral direction Y from the imaginary line VL, and furthermore, the absorbent body 4 is required to be positioned inside the side flap portions 6S in the lateral direction Y. In other words, the side flap portions according to the present invention overlap with the projected image of the absorbent body in the lateral direction.

Typically, a fastening part (not shown) for fastening the napkin 1 to the wearer's clothing is arranged on the non-skin-facing side of the napkin 1 (the non-skin-facing side of the backsheet 3). The fastening part can be any material conventionally used to fasten this type of absorbent article to clothing such as shorts, and can be, for example, a pressure-sensitive adhesive, a pressure-sensitive adhesive, etc.

The napkin 1 has the following outer shape of the rear region R.
First, the outer edges of the pair of side flap portions 6S, 6S have a pair of rear convex portions 65, 65 in the rear region R, which are located forward in the longitudinal direction X from the longitudinal rear end of the flap portion 6 and protrude outward in the transverse direction Y from the peripheral portion. Note that the "longitudinal rear end of the flap portion 6" refers to the longitudinal rear end 1R of the napkin 1.
In addition, the portion of the outer edge of the flap portion 6 sandwiched between the longitudinal rear end 1R and the rear convex portion 65 has an inwardly convexly curved portion 66 having a center of curvature outside the outer edge, and the inwardly convexly curved portion 66 has a single curved shape consisting of curved lines extending from each of the longitudinal rear end 1R and the rear convex portion 65 as starting points toward a single convex apex (maximum point) 66P located between the two starting points 1R and 65.
Furthermore, the apex 66P of the inwardly convex curved portion 66 (an imaginary straight line extending in the transverse direction Y through the pair of left and right apexes 66P, 66P) is located forward in the longitudinal direction X of the rear longitudinal end 4R of the absorbent body 4.

Due to the external shape of the rear region R, the napkin 1 has excellent leak-proofing properties, making it less likely for exudates to leak, and also flexibly twists and deforms when the wearer is walking, etc., making it extremely unlikely for the wearer to feel any discomfort. Specifically, in the napkin 1, the outer edges of the side flaps 6S have rear convex portions 65 in the rear region R, and the outer edges of the side flaps 6S, which are likely to be the starting point for deformation in the rear region R, have a single inwardly convex curved portion 66 between the rear convex portion 65 and the longitudinal rear end 1R. Therefore, when an external force that causes twisting in the rear region R is generated, such as when the wearer of the napkin 1 walks, the rear convex portion 65 becomes the twisting starting point, and the inwardly convex curved portion 66 easily twists and deforms in response to the external force. This ease of deformation can be evaluated using the "torsion torque value" measured by the method described below as an indicator. A napkin 1 having a rear convex portion 65 and a single inwardly convex curved portion 66 connected thereto has a sufficiently small torsion torque value, making it unlikely for the wearer to feel discomfort when twisted and deformed by the wearer's body movements.

Generally, if the rear region R is wide, it will be difficult for the rear region R to deform in response to the movement of the wearer's body (particularly the buttocks), which could cause discomfort when worn. Furthermore, generally, portions of the side flap portions 6S with a relatively narrow width (the length in the horizontal direction Y between the side edges 4S of the absorbent body 4 and the outer edges of the side flap portions 6S) are prone to undesirable deformation such as creases and folding, which could cause discomfort when worn. However, in the napkin 1, the apex 66P of the inwardly convex curved portion 66 is located forward in the vertical direction X of the rear longitudinal end 4R of the absorbent body 4, and therefore the apex 66P is positioned in close proximity to the relatively rigid absorbent body 4, making it less likely for the inwardly convex curved portion 66 to crease or fold.

<Method for measuring torsional torque value>
The absorbent article to be measured is used as a measurement sample. Figure 4 shows a measurement method when a sanitary napkin 100 is used as the measurement sample. The basic configuration of the napkin 100 is the same as that of the napkin 1 described above. As shown in Figure 4(a), both ends of the napkin 100 in the longitudinal direction X (longitudinal direction) are clamped between upper and lower clamps 101 and 102 provided on a tension-controlled torque tester (manufactured by Imada Co., Ltd.), and the napkin 100 is fixed between the upper and lower clamps 101 and 102. Next, as shown in Figures 4(b) and 4(c), the upper clamp 101 is rotated back and forth by 60° in the forward and reverse directions (forward and reverse rotations) around the longitudinal direction X of the napkin 100 as the rotation axis, and the torsional moment value (60° torsional torque value) applied to the napkin 100 is measured. Specifically, the back and forth rotation is performed 10 times, and 10 maximum torsional moment values in each of the forward and reverse directions are obtained. The average of the maximum values of the 10 points is then calculated for each of the forward and reverse directions, and the sum of the absolute values of both average values is taken as the torsional torque value (unit: Ncm) of the object being measured. This measurement is carried out for five measurement samples, and the average of the five measurements is calculated. The measurement is carried out with the tension applied to the measurement sample during rotation in the range of 3 to 6 N. During measurement, the length between the clamps is 175 mm under no tension. The torque tester used is in accordance with the one shown in Figure 2 of JIS K 7244-2.

In order to ensure the aforementioned effects resulting from the external shape of the rear region R are more reliably achieved, it is preferable that a pair of rear convex portions 65, 65 be present in the rearmost region when the napkin 1 is divided into three equal parts in the longitudinal direction X, and that the length (width) of the rearmost region in the transverse direction Y is the longest between the pair of rear convex portions 65, 65. The rearmost region either consists of at least the rear region R, or includes the excretory area facing region M and the rear region R.

To ensure the aforementioned effects resulting from the external shape of the rear region R are more reliably achieved, as shown in FIG. 3, the angle θ formed by two imaginary straight lines V1, V1 connecting the longitudinal rear end of the flap portion 6 and the apexes of the pair of rear convex portions 65, 65 (the outermost ends of the rear convex portions 65 in the horizontal direction Y) is preferably 40° or greater, more preferably 45° or greater, even more preferably 50° or greater, and preferably 100° or less, more preferably 95° or less, and even more preferably 90° or less. By adopting a configuration including a rear convex portion 65 and a single inwardly convex curved portion 66 connected thereto, the torsional torque value is reduced, thereby improving wearing comfort. By setting the angle θ within the above-mentioned preferred range, the length (width) of the rear region R in the horizontal direction Y is more appropriate from the perspective of leak prevention, and leakage of body waste from the rear region R can be more effectively prevented.

From the viewpoint of reducing the torsional torque value and further improving the wearing comfort, as shown in Fig. 3, it is preferable that the outer edge of the longitudinal rear end of the flap portion 6 (longitudinal rear end 1R of the napkin 1) has an outwardly convexly curved portion 67 having a center of curvature on the inside of the outer edge, and that the radius of curvature is smaller than that of the inwardly convexly curved portion 66. In other words, it is preferable that the outer edge of the longitudinal rear end of the flap portion 6 is the outwardly convexly curved portion 67 that is curved convexly outward in the longitudinal direction X of the napkin 1, and that the outwardly convexly curved portion 67 has a smaller radius of curvature and a sharper curve (larger curvature) than the inwardly convexly curved portion 66 connected thereto.

The ratio of the radius of curvature Rb of the outwardly convex curved portion 67 to the radius of curvature Ra of the inwardly convex curved portion 66, Rb/Ra, is preferably 0.05 or more, more preferably 0.1 or more, and preferably 0.9 or less, more preferably 0.85 or less, assuming Rb < Ra.
The radius of curvature Rb of the outwardly convex curved portion 67 is preferably 5 mm or more, more preferably 7 mm or more, and preferably 90 mm or less, more preferably 80 mm or less, provided that the radius of curvature Rb is smaller than the radius of curvature Ra of the inwardly convex curved portion 66.
The radius of curvature Ra of the inwardly convex curved portion 66 is preferably 10 mm or more, more preferably 15 mm or more, and preferably 120 mm or less, more preferably 100 mm or less, provided that the radius of curvature Ra is larger than the radius of curvature Rb of the outwardly convex curved portion 67.

In this embodiment, as shown in Fig. 3, the outer edge of the absorbent body 4 has a rear curved portion 47 that is connected to the longitudinal rear end 4R of the absorbent body 4 and extends along the inwardly curved portion 66 of the outer edge of the flap portion 6. The rear curved portion 47 has a center of curvature outside the outer edge of the absorbent body 4. By configuring the absorbent body 4 in the rear region R in this manner, the flexibility of the outer edge of the rear region R of the napkin 1 and its vicinity (edge portion) is improved, resulting in a further reduction in the torsional torque value and a further improvement in wearing comfort.
The radius of curvature of the rearward curved portion 47 and the radius of curvature of the inwardly convex curved portion 66 may be the same or different.
In order to more reliably achieve the effects attributable to the rearward curved portion 47, the ratio of the radius of curvature of the rearward curved portion 47 to the radius of curvature of the inward convex curved portion 66, as the former/the latter, is preferably 0.6 or more, more preferably 0.7 or more, and is preferably 1.4 or less, more preferably 1.3 or less.

5, when imagining a triangle whose base is an imaginary straight line H1 connecting the longitudinal front end 66A and longitudinal rear end 66B of the inwardly convex curved portion 66 and whose two sides are two imaginary straight lines H2, H3 connecting the apex (maximum point) 66P of the inwardly convex curved portion 66 to the front end 66A and rear end 66B, respectively, the angle (base angle) θ1 formed by the apex of the front end 66A in the triangle and the angle (base angle) θ2 formed by the apex of the rear end 66B in the triangle are preferably between 3° and 35°, and more preferably between 5° and 25°. Having angles θ1 and θ2 within the above ranges further improves the fit to the bulging area between the wearer's gluteal cleft and gluteal crease, and is expected to result in improved absorbency. When the angles θ1 and θ2 are 0°, this means that the apex 66P of the inwardly convex curved portion 66 is located on the imaginary line H1 (the base of the triangle), and when the angles θ1 and θ2 are greater than 0°, this means that the imaginary lines H2 and H3 (the two sides of the triangle other than the base) are located closer to the absorbent body 4 than the imaginary line H1 in the direction perpendicular to the imaginary line H1.

In this embodiment, as shown in FIG. 1 , the front side of the inwardly convex curved portion 66 in the longitudinal direction X, including the front longitudinal end 66A, is at the same position in the longitudinal direction X as the absorbent body 4, and the remaining portion (the rear side in the longitudinal direction X, including the rear longitudinal end 66B) is located rearward of the absorbent body 4 in the longitudinal direction X, and includes a portion that overlaps with the absorbent body 4 in the longitudinal direction X.
In the present invention, the inwardly convexly curved portion 66 does not have to include a portion that overlaps with the absorbent body 4 in the longitudinal direction X, i.e., the proportion of this portion in the inwardly convexly curved portion 66 (hereinafter also referred to as the "absorbent body overlapping portion occupancy rate") may be zero, but from the viewpoint of ensuring that the aforementioned functional effects resulting from the outer shape of the rear region R are achieved, it is preferable that the absorbent body overlapping portion occupancy rate is not zero, as in the present embodiment, and a high absorbent body overlapping portion occupancy rate is more preferable. Specifically, the absorbent body overlapping portion occupancy rate in the inwardly convexly curved portion 66 is preferably 50% or more, and more preferably 70% or more.
5, the absorbent overlapping portion occupancy rate of the inwardly convexly curved portion 66 is "the proportion of a length 66L1 in the extending direction of the portion overlapping with the absorbent 4 in the longitudinal direction X to the length 66L of the inwardly convexly curved portion 66 (i.e., the length of an imaginary line H1 connecting a longitudinal front end 66A and a longitudinal rear end 66B of the inwardly convexly curved portion 66)." The length 66L1 is the length between the longitudinal front end 66A of the inwardly convexly curved portion 66 and a point P1 on the imaginary line H1, and the point P1 is the intersection of the imaginary line H1 and an imaginary line H4 that passes through the longitudinal rear end 4R of the absorbent 4 and extends parallel to the transverse direction Y.

Referring to Figure 3, the ratio L2/L1 of the length L1 in the longitudinal direction X between the rear convexity 65 and the longitudinal rear end of the flap portion 6 (the longitudinal rear end 1R of the napkin 1) to the length (width) L2 in the transverse direction Y of the region in the flap portion 6 (napkin 1) between the rear convexity 65 and the longitudinal rear end of the flap portion 6 (the longitudinal rear end 1R of the napkin 1) is preferably 0.5 or more, more preferably 0.6 or more, and preferably 1.3 or less, more preferably 1.2 or less. With L2/L1 within this range, it becomes possible to secure sufficient space for the absorbent body 4 in the region of the napkin 1 located rearward of the rear convexity 65 in the longitudinal direction X, and further improvement in leak prevention can be expected.

Referring to Figure 3, the length (width) L3 in the transverse direction Y of the flap portion 6 (napkin 1) at the same position in the longitudinal direction X as the longitudinal rear end 4R of the absorbent body 4 is preferably 45 mm or more, more preferably 50 mm or more, and preferably 90 mm or less, more preferably 80 mm or less. By keeping the length L3 within this range, it is possible to relatively increase the area of the longitudinal rear end 4R of the absorbent body 4 and its vicinity, which is expected to improve leak prevention.

In this embodiment, as shown in Figures 1 and 3, the outer edge of the side flap portion 6S has a rear constricted portion 62 that is located forward of the rear convex portion 65 in the longitudinal direction X and is connected to the rear convex portion 65. With this configuration, the napkin 1 has a further reduced torsional torque value, making it less likely for the wearer to feel uncomfortable even when the wearer's body movements are relatively active. From the perspective of more reliably achieving this effect, it is preferable that the rear constricted portion 62 be located in the rear region R and adjacent to the rear convex portion 65, as shown in the figure.

Furthermore, in this embodiment, as shown in Figure 1, the outer edge of the side flap portion 6S has a front constricted portion 61 in the front region F. With this configuration, the napkin 1 has an even lower torsional torque value, making it less likely to cause discomfort to the wearer even when the wearer's body is relatively active.

To further explain the constricted portions 61, 62, in this embodiment, the outer edge of the side flap portion 6S, more specifically, the side edge of the side flap portion 6S along the longitudinal direction X, has a front constricted portion 61 located in the front region F and a rear constricted portion 62 located in the rear region R, as shown in Figure 1, and the portion sandwiched between the constricted portions 61, 62 (an inter-constricted portion region described below) has a curved portion 63 that is convex outward in the lateral direction Y. The curved portion 63 extends over the entire length of the excretory portion-facing region M in the longitudinal direction X.
There is no inflection point in the portion of the outer edge of the side flap portion 6S sandwiched between the two constricted portions 61, 62. Both constricted portions 61, 62 are curved inward in the lateral direction Y. In the present invention, either or both of the two constricted portions 61, 62 may be curved inward in the lateral direction Y and configured as a straight line.
1, the outer edges of the flap portions 6 (side flap portions 6S, front flap portion 6F) have front convex portions 64 that are located forward of the front constricted portion 61 in the longitudinal direction X, are connected to the front constricted portion 61, and protrude in a direction away from the absorbent core 4. Similar to the rear convex portion 65, the front convex portion 64 protrudes outward in the transverse direction Y from the peripheral portion.

In this embodiment, the napkin 1 is a pad-type absorbent article. In the present invention, a "pad-type absorbent article" refers to an absorbent article that does not have wing portions. As described above, the "wing portions" are areas that are manually folded over with the fingers toward the non-skin-facing side of the crotch portion when fastening the absorbent article to the skin-facing side of the crotch portion of clothing such as shorts. Typically, in the case of napkin 1, these are portions of the side flap portions 6S located in the excretory area M that extend farther outward in the lateral direction Y than the surrounding area. Napkin 1 does not have portions, such as wing portions, that are manually folded over with the fingers toward the non-skin-facing side of clothing when worn.

As shown in FIG. 1, in the napkin 1, part of the outer edge of the side flap portion 6S has a curved portion 63 that protrudes outward in the lateral direction Y and extends further outward in the lateral direction Y than the peripheral portion. However, unlike the wing portion, the side flap portion 6S is not folded back toward the non-skin-facing side of the garment by manual manipulation using fingers when fastening the napkin 1 to the garment, and is therefore clearly distinguishable from the wing portion.
In the napkin 1, the distance G1 (see FIG. 1 ) in the horizontal direction Y between the outer edge (side edge along the vertical direction X) of the side flap portion 6S and the absorbent body 4 is typically about 35 mm at most. In contrast, in absorbent articles equipped with wing portions, from the viewpoint of facilitating manual folding of the wing portions with the fingers, the horizontal length of the wing portions, i.e., the distance between the tip (outermost end in the horizontal direction) of the wing portions and the absorbent body, usually significantly exceeds the typical maximum value of 35 mm for the distance G1 .

Because the napkin 1 is a pad-type absorbent article without wings, it can be easily put on without the complicated donning operation that is a problem specific to absorbent articles with wings. That is, when putting the napkin 1 on a wearer's crotch area, the wearer usually first puts shorts over both legs, and before fitting the shorts to the crotch area, fastens the napkin 1 to the skin-facing surface (inner surface) of the crotch area of the shorts via a fastening part (not shown) that the napkin 1 has, and then pulls the shorts toward the crotch area to put the napkin 1 on the crotch area. 6 shows the napkin 1 in this state when worn in the crotch area of the wearer, with the napkin 1 fastened to the skin-facing surface of the crotch area 21 of the shorts 20 via the fastening portion, and with a portion of the side flap area 6S (the curved area 63 and its vicinity) bent along the side edge of the crotch area 21 away from the crotch area and disposed along the wearer's thighs 30. The bent areas of the side flap areas 6S in this worn state have the same function as the wing areas of conventional sanitary napkins, and can provide effects such as preventing the napkin 1 from shifting from its correct position while being worn, improving the fit of the napkin 1 to the wearer's body, and preventing leakage of body waste, but achieving this bent state does not require the manual bending operation using fingers that is required for wing areas. That is, when the napkin 1 is fastened via the fastening portion to the skin-facing surface of the crotch portion 21 of the shorts 20 with the wearer's legs 30, 30 passed through, the portions sandwiched between the front constriction portion 61 and the rear constriction portion 62 of each of the pair of side flap portions 6S, 6S (portions whose outer edges are curved portions 63) extend from both side edges of the crotch portion 21, and when the shorts 20 are pulled toward the wearer's crotch in this state, the extending portions of the side flap portions 6S extending from the crotch portion 21 naturally bend along the side edges of the crotch portion 21 in the opposite direction to the direction in which the shorts 20 are pulled, and when the napkin 1 comes into contact with the crotch, the extending portions follow the wearer's legs (thighs) 30, as shown in Figure 6.
In this way, the extension portion of the side flap portion 6S from the crotch portion 21 can be naturally folded along the side edge of the crotch portion 21 simply by pulling it toward the crotch side of the shorts 20, without any artificial folding operation using fingers, largely due to the action of the two constricted portions 61, 62 provided on the outer edge of the side flap portion 6S. That is, the front constricted portion 61 and the rear constricted portion 62 are arranged at a distance from each other on the outer edge of the side flap portion 6S with the curved portion 63 in between, so that the curved portion 63 of the side flap portion 6S and its vicinity are easily deformed when subjected to an external force. Therefore, by simply fastening the napkin 1 at an appropriate fastening position in the crotch portion 21 so that the curved portion 63 and its vicinity extend from the side edge of the crotch portion 21, all that is required is to pull the shorts 20 toward the crotch, and the curved portion 63 extending from the side edge of the crotch portion 21 and its vicinity will be easily deformed by the external force acting through the wearer's legs (thighs).

In order to further ensure the aforementioned effect of easy donning of the napkin 1, it is preferable that the fastening portion (the component for fastening the napkin 1 to the wearer's clothing) be located in an area that overlaps with the absorbent body 4 in a plan view, and not in the flap portion 6 (side flap portion 6S).

In order to ensure the above-described effects of the flap portion 6, it is preferable to set the dimensions of each portion of the napkin 1 as follows.
The front constricted portion 61 is preferably positioned at a position rearward in the longitudinal direction X from the longitudinal front end 1F of the napkin 1 (the longitudinal front end of the flap portion 6), preferably at least 40 mm, more preferably at least 50 mm, and preferably within 150 mm, more preferably within 140 mm.
The rear constricted portion 62 is preferably positioned at a position forward in the longitudinal direction X from the longitudinal rear end 1R of the napkin 1 (the longitudinal rear end of the flap portion 6), preferably at least 100 mm, more preferably at least 120 mm, and preferably within 350 mm, more preferably within 330 mm.
The distance G2 (see FIG. 1) between the front constricted portion 61 and the rear constricted portion 62 in the longitudinal direction X is preferably 40 mm or more, more preferably 60 mm or more, and is preferably 250 mm or less, more preferably 230 mm or less.
The maximum length (maximum width) of the napkin 1 in the transverse direction Y is preferably 60 mm or more, more preferably 80 mm or more, and preferably 200 mm or less, more preferably 180 mm or less. The portion of the napkin 1 having the maximum width is typically located in the excretory region M, which in the illustrated embodiment is the portion where the apex of the convex curved portion 63 of the side flap portion 6S is located.
The total length of the napkin 1 in the longitudinal direction X is preferably 100 mm or more, more preferably 140 mm or more, and is preferably 450 mm or less, more preferably 420 mm or less.

The distance G3 (see Figure 1) between the apex 66P of the inwardly convex curved portion 66 and the absorbent body 4 is preferably 4 mm or more, more preferably 5 mm or more, and preferably 30 mm or less, more preferably 20 mm or less, from the perspective of ensuring sufficient absorption capacity while reducing the excessive contribution of the rigidity of the absorbent body 4 and making it easier to demonstrate the functional effects of the characteristic outer shape of the rear region R.

1 , in the region overlapping with the absorbent body 4 in a plan view (absorbent body arrangement region), the inter-constriction region located between the rear constriction region 62 and the front constriction region 61 in the longitudinal direction X has higher compression recovery than the region adjacent to the inter-constriction region in the longitudinal direction X. The inter-constriction region with high compression recovery has excellent cushioning properties, deforms responsively to external forces, and quickly returns to its original state when the external force is released. The inter-constriction region extends over the entire length of the excretory part-facing region M in the longitudinal direction X, and therefore the excretory part-facing region M is a region with relatively high compression recovery. This configuration improves the fit of the excretory part-facing region M to the wearer's body , improving the fit and conformability of the entire napkin 1 to the body, and is expected to further improve leak prevention and wearing comfort.

The "compression recoverability" can be evaluated using the compression work (hereinafter also referred to as "WC") and recovery work (hereinafter also referred to as "WC ' ") as indicators. WC is an indicator of the cushioning properties of the object to be measured, and the larger the WC value, the better the cushioning of the object to be measured, and therefore the better the compression recoverability. WC' is an indicator of the recoverability (compression recoverability) of the object to be measured when an external force is applied to the object to compress it and then the external force is removed, and the larger the WC ' value, the better the compression recoverability of the object to be measured. WC and WC ' are each measured by the following methods.

<Method of measuring compression work (WC) and recovery work (WC ' )>
It is generally known that the WC and WC ' to be measured can be expressed as values measured using the KES (Kawabata Evaluation System) manufactured by Kato Tech Co., Ltd. (Reference: Standardization and Analysis of Texture Evaluation (2nd Edition), author Kawabata Toshio, published July 10, 1980). Specifically, WC and WC ' can be measured using a compression testing device KES-G5 manufactured by Kato Tech Co., Ltd. The measurement procedure is as follows.
First, a sample is attached to the test stand of the compression tester. The sample is, for example, an absorbent article such as a napkin 1 or a component thereof (e.g., an absorbent core 4). The sample is dry and has a rectangular shape in plan view, measuring 5 mm in length and 5 mm in width. If the dry sample is an absorbent core or an absorbent article containing the same, the absorbent core is unused, has not absorbed any liquid, and is in a dry state. Next, the sample is compressed between steel plates with a circular flat surface having an area of 2 ^cm2 . The portion to be compressed is the non-recessed portion of the sample, i.e., the portion that has not been subjected to compression processing and retains its original shape. The compression speed is 0.2 cm/sec, the maximum compression load is 2450 mN/ ^cm2 , SENS is 10, and DEF is 20. The recovery process is also measured at the same speed. WC is expressed by the following formula (1), and WC ' is expressed by the following formula (2), each in units of "mN·cm/ ^cm2 ." In the following formula, _Tm represents the thickness under a load of 2450 mN/ ^cm2 (4.9 kPa), and _T0 represents the thickness under a load of 4.902 mN/ ^cm2 (49 Pa). Furthermore, Pa in the following formula (1) and Pb in the following formula (2) represent the measured load (mN/ ^cm2 ) during the compression process and the measured load (mN/ ^cm2 ) during the thickness recovery process, respectively.

It should be noted that WC ' is not displayed on the measurement result screen of the KES-G5, but rather, what is displayed on the measurement result screen is WC and the compression recovery rate or compression resilience (hereinafter also referred to as "RC") calculated from WC ' . In such a case, WC ' is calculated using the parameters (WC, RC) displayed on the testing device by the following formula:

The ratio of the WC of the inter-constriction region to the WC of a region in front of it (e.g., a front region F) or a region behind it (e.g., a rear region R) in the longitudinal direction X is preferably 1.5 or more, more preferably 1.7 or more, assuming that the former is greater than the latter.
The WC of the inter-constricted region is preferably 100 mN cm/ ^cm2 or more, more preferably 120 mN cm/cm2 or ^more . There is no particular upper limit to the WC of the inter-constricted region, but from the viewpoint of reducing the thickness of the absorbent article in an individually packaged state, it is preferably 300 mN cm/ ^cm2 or less, more preferably 280 mN cm/cm2 or ^less .

The ratio of WC ' of the inter-constriction region to WC ' of a region in front of it (e.g., a front region F) or a region in rear of it (e.g., a rear region R) in the longitudinal direction X is preferably 1.5 or more, more preferably 1.7 or more, assuming that the former is greater than the latter.
The WC ' of the inter-constricted region is preferably 100 mN cm/ ^cm2 or more, more preferably 120 mN cm/cm2 or ^more . There is no particular upper limit to the WC ' of the inter-constricted region, but from the viewpoint of reducing the thickness of the individually packaged absorbent article, it is preferably 300 mN cm/cm2 or ^less , more preferably 280 mN cm/cm2 or ^less .

The difference in compression recovery in the napkin 1 (absorbent body 4) described above is due to the presence or absence of the fiber agglomeration layer 42. That is, the inter-constriction region (excretory region M) contains the fiber agglomeration layer 42, and therefore has higher compression recovery than other regions that do not contain it.

As shown in Figure 2, the fiber agglomerate layer 42 is primarily composed of fiber agglomerates 11 containing non-absorbent fibers. Here, "primarily composed of fiber agglomerates" means that the fiber agglomerates 11 account for 90% by mass or more of all fibers constituting the fiber agglomerate layer 42, preferably 95% by mass or more, and more preferably 100% by mass. The fiber agglomerates 11 are fiber aggregates formed by accumulating and integrating a plurality of non-absorbent fibers into agglomerated shapes, and are present in the absorbent body 4 (fiber agglomerate layer 42) while retaining their shape. Due to the shape of the fiber aggregate, the fiber agglomerates 11 primarily contribute to improving the flexibility, cushioning properties, compression recovery, and shape retention of the absorbent body 4.
The non-absorbent fibers that make up the fiber agglomerates 11 are preferably fibers (non-absorbent fibers) that have lower absorbency than the absorbent fibers such as cellulosic fibers used as the absorbent material in the absorbent core 40, and specific examples include synthetic fibers primarily made of thermoplastic resin. By including non-absorbent fibers in the fiber agglomerates 11, the properties of the fiber agglomerates 11, such as flexibility, can be fully exhibited even when the fiber agglomerates 11 come into contact with body fluids.
The shape of the fiber agglomerates 11 is not particularly limited and may be irregular, but regular shapes such as sheet pieces obtained by cutting a synthetic fiber sheet to a certain size can also be used. Examples of such regular fiber agglomerates that can be suitably used include the fiber agglomerates described in JP 2019-063469 A, JP 2019-098157 A, and JP 2020-188918 A, specifically, fiber agglomerates having two opposing base surfaces and a skeletal surface connecting the two base surfaces.

The fiber agglomerate layer 42 is a region in which the fiber agglomerates 11 are present across the entire length of the absorbent body 4 in the lateral direction Y. The fiber agglomerate layer 42 may be composed of only the fiber agglomerates 11, or may contain an absorbent material in addition to the fiber agglomerates 11. A fiber agglomerate layer 42 containing an absorbent material is capable of absorbing and retaining body fluids, thereby improving the absorption performance of the absorbent body 4. Any absorbent material that can be used in the absorbent core 40 can be used for the fiber agglomerate layer 42 without any particular restrictions.

In this embodiment, the fiber agglomerate layer 42 contains fiber agglomerates 11, as shown in FIG. 2 . Typically, the fiber agglomerate layer 42 contains only fiber agglomerates 11. Preferably, the fiber agglomerates 11 are entangled with each other in the fiber agglomerate layer 42. Such a configuration of the fiber agglomerate layer 42 improves the shape retention of the fiber agglomerate layer 42, allowing the absorbent body 4 including the fiber agglomerate layer 42 to deform appropriately and with good followability to external forces received from various directions during wear, and furthermore, to have excellent flexibility, cushioning properties, and compression recovery. The napkin 1 including such an absorbent body 4 easily deforms and recovers from external forces, is resistant to wrinkling, and has an excellent fit to the wearer's body. Furthermore, it is more preferable that the fiber agglomerates 11 of the fiber agglomerate layer 42 and the absorbent core 40 disposed thereon be entangled at the interface between the former and the latter absorbent fibers.
The term "entanglement" as used herein includes both (i) a form in which the entangled objects (fiber agglomerates or fiber agglomerates and absorbent fibers) are not fused to each other, but the bonded state is maintained by the entanglement of the constituent fibers of the fiber agglomerates, and (ii) a form in which, in the natural state of the absorbent article (absorbent body) (a state in which no external force is applied), the fiber agglomerates or the fiber agglomerates and absorbent fibers are not bonded to each other, but when an external force is applied to the absorbent article (absorbent body), the fiber agglomerates or the fiber agglomerates and absorbent fibers can be bonded to each other by the entanglement of the constituent fibers.

In this embodiment, in the excretory part-facing region M, as shown in FIG. 2 , the skin-facing side of the absorbent body 4 comprises an absorbent core 40 mainly composed of absorbent fibers 12 and absorbent polymer particles 13, and does not substantially contain fiber agglomerates 11, whereas the non-skin-facing side of the absorbent body 4 comprises a fiber agglomerate layer 42 mainly composed of fiber agglomerates 11.
More specifically, in this embodiment, in the absorbent 4 in the excretory part-facing region M, the fiber agglomeration rate calculated by the following formula ( A ) is lower on the skin-facing side than on the non-skin-facing side. In other words, in this embodiment, fiber agglomerates 11 are unevenly distributed on the non-skin-facing side of the absorbent 4. More specifically, in the excretory part-facing region M, the skin-facing side of the absorbent 4 may have absorbent fibers 12 unevenly distributed and the content of fiber agglomerates 11 may be zero, whereas the non-skin-facing side of the absorbent 4 may have absorbent fibers 11 unevenly distributed and the content of absorbent fibers 12 may be zero.
Here, the "skin-facing side of the absorbent body" refers to the side that includes the skin-facing surface when the absorbent body 4 is divided into two equal parts in the thickness direction (the side that is relatively closer to the wearer's skin), and the "non-skin-facing side of the absorbent body" refers to the opposite side (the side that is relatively farther from the wearer's skin).
In this way, in the absorbent 4 in the excretory part-facing region M, the above-mentioned magnitude relationship of "skin-facing side of absorbent 4 < non-skin-facing side of absorbent 4" is established for the fiber agglomeration rate, and therefore the action of the absorbent fibers unevenly distributed on the skin-facing side of the absorbent 4 improves the absorbent 4's ability to draw in body fluids (capillary force), thereby improving its liquid absorption, and the action of the fiber agglomerates 11 unevenly distributed on the non-skin-facing side of the absorbent 4 can improve the cushioning properties, etc. of the absorbent 4.

The fiber agglomerate occupancy is determined by measuring the mass of each of the fiber agglomerates and the water-absorbent material present in a predetermined measurement area of the absorbent body, and dividing the measured mass of the fiber agglomerates by the total mass of the fiber agglomerates and the water-absorbent material, expressed as a percentage. The water-absorbent material is as described above, and is typically a water-absorbent fiber and/or a water-absorbent polymer.
Fiber agglomerate occupancy (mass%) = {fiber agglomerate mass/(water-absorbent material mass+fiber agglomerate mass)} × 100 ( A )

The present invention has been described above based on its preferred embodiments, but the present invention is not limited to the above embodiments and can be modified as appropriate within the scope of the invention.
For example, the skin-facing surface of the napkin 1 may have a recess formed by the topsheet 2 and absorber 4 forming the skin-facing surface being recessed integrally toward the non-skin-facing surface (backsheet 3). In this case, the recess may include a linear vertical recess extending in the longitudinal direction X and/or a linear horizontal recess extending in the lateral direction Y.
The absorbent article of the present invention includes articles used to absorb body fluids discharged from the human body (menstrual blood, urine, loose stool, sweat, etc.), and is not limited to the sanitary napkins mentioned above.

The following supplementary notes are further disclosed regarding the above-described embodiment of the present invention.
<1>
An absorbent article comprising an absorbent body capable of absorbing and retaining bodily fluids, having a longitudinal direction corresponding to the front-to-rear direction of a wearer and a lateral direction perpendicular to the longitudinal direction, and having an excretory part facing region that is disposed to face the excretory part of the wearer when worn, a front region that is disposed forward of the excretory part facing region in the longitudinal direction, and a rear region that is disposed rearward of the excretory part facing region in the longitudinal direction,
a flap portion extending outward from the outer edge of the absorbent body and forming an outline of the absorbent article, the flap portion comprising a pair of side flap portions positioned outward in the horizontal direction from a pair of imaginary straight lines extending in the vertical direction through the outermost end of the absorbent body in the horizontal direction;
The absorbent body is located inside the side flap portion in the lateral direction,
The outer edges of the pair of side flap portions have a pair of rear convex portions in the rear region, which are located forward in the longitudinal direction from the rear ends of the flap portions and protrude outward in the lateral direction from the peripheral portions,
a portion of the outer edge of the flap portion sandwiched between the longitudinal rear end of the flap portion and the rear convex portion has an inward convex curved portion having a center of curvature outside the outer edge,
The inward convex curved portion has a single curved shape consisting of curved lines extending from the longitudinal rear end of the flap portion and the rear convex portion as starting points toward a single convex apex located between the two starting points, and the apex is located longitudinally forward of the longitudinal rear end of the absorbent body, in an absorbent article.
<2>
The absorbent article according to <1>, wherein the outer edge of the longitudinal rear end of the flap portion has an outwardly convexly curved portion having a center of curvature on the inside of the outer edge, and has a smaller radius of curvature than the inwardly convexly curved portion.
<3>
The absorbent article according to <1> or <2>, wherein the outer edge of the absorbent body has a rear curved portion that is connected to the longitudinal rear end of the absorbent body and extends along the inward convex curved portion of the outer edge of the flap portion.
＜4＞
The absorbent article according to any one of <1> to <3>, wherein an outer edge of the side flap portion has a rear constricted portion that is located forward of the rear convex portion in the longitudinal direction and is connected to the rear convex portion.
<5>
The absorbent article according to <4>, wherein the outer edges of the side flap portions have a front constricted portion in the front region.
<6>
The absorbent article described in <5>, wherein in a region overlapping with the absorbent body in a planar view, an inter-constriction region located between the rear constriction region and the front constriction region in the longitudinal direction has higher compression recovery than a region adjacent to the inter-constriction region in the longitudinal direction.
＜７＞
The absorbent article described in <6>, wherein the ratio of the compression work WC of the inter-constriction region to the compression work WC of the front region or the rear region in the longitudinal direction is preferably 1.5 or more, more preferably 1.7 or more, assuming that the former is greater than the latter.

＜8＞
The absorbent article according to any one of <1> to <7>, wherein a pair of the rear convex portions is present in the rearmost region when the absorbent article is divided into three equal parts in the longitudinal direction, and the length of the rearmost region in the lateral direction is the longest between the pair of the rear convex portions.
＜９＞
<1> The absorbent article according to any one of <1> to <8>, wherein an angle formed by two imaginary lines connecting the longitudinal rear end of the flap portion and the peaks of the pair of rear convex portions is 40 to 100 degrees.
<10>
The absorbent article according to any one of <1> to <9>, wherein the ratio L2/L1 of the length L1 in the vertical direction between the rear convex portion and the rear end of the flap portion in the vertical direction to the length L2 in the horizontal direction of the region of the flap portion between the rear convex portion and the rear end of the flap portion in the vertical direction is preferably 0.5 or more, more preferably 0.6 or more, and is preferably 1.3 or less, more preferably 1.2 or less.
<11>
The absorbent article according to any one of <1> to <10>, wherein the length (width) (L3) in the horizontal direction of the flap portion at the same position in the vertical direction as the vertical rear end of the absorbent body is preferably 45 mm or more, more preferably 50 mm or more, and preferably 90 mm or less, more preferably 80 mm or less.
<12>
The absorbent article according to any one of <1> to <11>, wherein, when a triangle is imagined, the base of which is an imaginary line connecting the longitudinal front end and the longitudinal rear end of the inwardly convexly curved portion, and the two sides of which are two imaginary lines connecting the apex (maximum point) of the inwardly convexly curved portion to the longitudinal front end and the longitudinal rear end, respectively, an angle (θ1) formed by a vertex of the longitudinal front end of the triangle and an angle (θ2) formed by a vertex of the longitudinal rear end of the triangle are each 3° or more and 35° or less, preferably 5° or more and 25° or less.
<13>
The absorbent article according to any one of <1> to <12>, wherein the inwardly convexly curved portion includes a portion that overlaps with the absorbent body in the longitudinal direction, and a proportion of the inwardly convexly curved portion that is occupied by the portion (absorbent body overlapping portion occupancy rate) is preferably 50% or more, more preferably 70% or more.

<14>
The absorbent article according to any one of <1> to <13>, wherein the absorbent body comprises fiber agglomerates containing absorbent fibers and non-absorbent fibers, and the fiber agglomerates are entangled with each other or with the absorbent fibers.
＜15＞
The absorbent article according to <14>, wherein the absorbent body includes a fiber agglomeration layer mainly composed of the fiber agglomerations.
<16>
The absorbent article according to <15>, wherein the fiber mass layer is present in an inter-constricted portion region located between the rear constricted portion and the front constricted portion in the longitudinal direction.
＜17＞
The absorbent article according to <15> or <16>, wherein in the excretory part facing region, the skin facing side of the absorbent body is made of an absorbent core mainly composed of absorbent fibers and absorbent polymer particles, and the non-skin facing side of the absorbent body is made of the fiber mass layer.
＜18＞
The absorbent article according to any one of <15> to <17>, wherein the fiber agglomeration layer is a region in which the fiber agglomerations are present over the entire length of the absorbent body in the lateral direction.
＜19＞
<15> to <18>, wherein the fiber agglomerates in the fiber agglomerate layer account for 100% by mass.
＜20＞
The absorbent article according to any one of <1> to <19>, wherein the absorbent article is a sanitary napkin.

[Experimental Example]
The present invention will be explained in more detail below by way of experimental examples, but the present invention is not limited to these experimental examples. Experimental Examples 4 to 6 are reference examples.

[Experimental Example 1]
A sanitary napkin was produced having the same basic structure as the napkin 1 shown in Figure 1. Details of the main components of the sanitary napkin of Experimental Example 1 are as follows.
Top sheet: An air-through nonwoven fabric (basis weight 28 g/m ² ) was used.
Back sheet: A polyethylene resin film (basis weight 38 g/m ² ) was used.
Side sheet: A spunbond nonwoven fabric (basis weight 20 g/m ² ) was used.
Absorbent core: A stacked fiber type was used in which absorbent polymer particles (50 g/m ² ) were carried on a fiber aggregate made of absorbent fibers (softwood bleached kraft pulp, basis weight 200 to 210 g/m ² ).
Core wrap sheet: tissue (basis weight 16 g/m ² ) was used.
Fiber agglomerate layer: A mixture of 200 g/m ² of fiber agglomerates and 210 g/m ² of water-absorbing fiber (softwood bleached kraft pulp) was used. The fiber agglomerates were produced by the following method.

(Method for producing fiber mass)
The fiber agglomerates were produced according to the method described in JP 2019-063469 A. Specifically, a raw fiber sheet was cut into a dice pattern to produce rectangular parallelepiped fiber agglomerates (fiber agglomerates having two opposing base surfaces and a skeletal surface connecting the two base surfaces). The raw fiber sheet used was an air-through nonwoven fabric (a fiber sheet having heat-fused portions between the constituent fibers) with a basis weight of 25 g/ ^m² , whose constituent fibers were hydrophobic thermoplastic fibers (non-absorbent fibers, fiber diameter 18 μm) made of polyethylene resin and polyethylene terephthalate resin. The fiber agglomerates had a short side of the base surface of 3.9 mm, a long side of 5 mm, and a thickness of 0.6 mm.

[Experimental Examples 2 to 6]
Sanitary napkins 1A to 1E shown in Figures 7 and 8 were produced. Napkins 1A to 1E are basically constructed in the same manner as the above-mentioned napkin 1 (the sanitary napkin of Experimental Example 1), except for the components described below. In Figures 7 and 8, components in napkins 1A to 1E that are similar to those in napkin 1 are given the same reference numerals as those in napkin 1. For components in napkins 1A to 1E that are not specifically described, the explanation for napkin 1 above applies as appropriate.
The napkin 1A shown in Figure 7(a) differs from the napkin 1 in the radii of curvature Ra, Rb of the inwardly convex curved portion 66 and the outwardly convex curved portion 67 in the rear region R, and in the ratio Rb/Ra between them. Also, the outer shapes of the front region F and the portion of the excretory-facing region M closer to the front region F differ from those of the napkin 1. The rear region R of the napkin 1A is the same as that of the napkin 1. Compared to the napkin 1, the napkin 1A has a sharper curve at the longitudinal front end of the flap portion 6 (the longitudinal front end 1F of the napkin 1), and the distance in the longitudinal direction X between the front constricted portion 61 and the longitudinal front end 1F of the napkin 1 is longer.
The napkin 1B shown in FIG. 7B differs from the napkin 1 in the angle θ as well as the radii of curvature Ra, Rb and the ratio Rb/Ra of the inwardly convexly curved portion 66 and the outwardly convexly curved portion 67 of the rear region R.
The napkin 1C shown in Figure 8(a) and the napkin 1D shown in Figure 8(b) both have significantly different overall external shapes from the napkin 1, but the main differences are that the angle θ exceeds 100° and the apex 66P of the inwardly convex curved portion 66 is located further rearward in the longitudinal direction X than the longitudinal rear end 4R of the absorbent body 4.
The napkin 1E shown in Figure 8(c) differs from the napkin 1 in that the portion of the outer edge of the flap portion 6 between the longitudinal rear end 1R and the rear convex portion 65 does not have an inwardly convexly curved portion 66 having a center of curvature on the outer side of the outer edge. It also differs from the napkin 1 in that the outer edge of the absorbent body 4 does not have a rearly curved portion 47 (see Figure 3) that extends along the inwardly convexly curved portion 66 of the outer edge of the flap portion 6.

The torsional torque value of the sanitary napkins of each experimental example was measured using the method described above. Furthermore, the "recovery work WC' of the fiber aggregate layer region / recovery work WC' of the region adjacent to that region in the longitudinal direction" was calculated. The recovery work WC' was measured using the method described above. Here, the "region adjacent to the fiber aggregate layer region in the longitudinal direction" refers to the region corresponding to the rear region R of the napkin 1. The results are shown in Table 1 below.

1, 1A, 1B, 1C, 1D, 1E Sanitary napkin (absorbent article)
1F: Front end of the sanitary napkin in the vertical direction (front end of the flap in the vertical direction)
1R: The rear end of the sanitary napkin in the vertical direction (the rear end of the flap in the vertical direction)
2 topsheet 3 backsheet 4 absorbent body 40 absorbent core 41 core wrap sheet 42 fiber agglomerate layer 47 rear curved portion 5 sidesheet 6 flap portion 6S side flap portion 61 front constricted portion 62 rear constricted portion 65 rear convex portion 66 inwardly convexly curved portion 66P apex of inwardly convexly curved portion 67 outwardly convexly curved portion 11 fiber agglomerates 12 water-absorbent fiber F front region M excretory portion facing region R rear region X longitudinal direction Y transverse direction

Claims (8)

An absorbent article comprising an absorbent body capable of absorbing and retaining bodily fluids, having a longitudinal direction corresponding to the front-to-rear direction of a wearer and a lateral direction perpendicular to the longitudinal direction, and having an excretory part facing region that is disposed to face the excretory part of the wearer when worn, a front region that is disposed forward of the excretory part facing region in the longitudinal direction, and a rear region that is disposed rearward of the excretory part facing region in the longitudinal direction,
a flap portion extending outward from the outer edge of the absorbent body and forming an outline of the absorbent article, the flap portion comprising a pair of side flap portions positioned outward in the horizontal direction from a pair of imaginary straight lines extending in the vertical direction through the outermost end of the absorbent body in the horizontal direction;
The absorbent body is located inside the side flap portion in the lateral direction,
The outer edges of the pair of side flap portions have a pair of rear convex portions in the rear region, which are located forward in the longitudinal direction from the rear ends of the flap portions and protrude outward in the lateral direction from the peripheral portions,
a portion of the outer edge of the flap portion sandwiched between the longitudinal rear end of the flap portion and the rear convex portion has an inward convex curved portion having a center of curvature outside the outer edge,
the inward convex curved portion has a single curved shape consisting of curved lines extending from the longitudinal rear end of the flap portion and the rear convex portion as starting points toward a single convex apex located between the two starting points, and the apex is located forward in the longitudinal direction of the longitudinal rear end of the absorber ,
the angle formed by two imaginary lines connecting the longitudinal rear end of the flap portion and the peaks of the pair of rear convex portions is 40 to 100 degrees;
The outer edge of the longitudinal rear end of the flap portion has an outwardly convexly curved portion having a center of curvature on the inside of the outer edge, and having a smaller radius of curvature than the inwardly convexly curved portion . 2. The absorbent article according to claim 1, wherein, when a triangle is imagined, the base of which is an imaginary line connecting the longitudinal front end and the longitudinal rear end of the inward convex curved portion, and the two sides of which are two imaginary lines connecting the apex of the inward convex curved portion to the longitudinal front end and the longitudinal rear end, respectively, the angle formed by the vertex of the longitudinal front end of the triangle and the angle formed by the vertex of the longitudinal rear end of the triangle are each between 3° and 35° . The absorbent article according to claim 2 , wherein the inwardly convexly curved portion includes a portion that overlaps with the absorbent body in the longitudinal direction, and the portion occupies 70% or more of the inwardly convexly curved portion. The absorbent article according to any one of claims 1 to 3, wherein the outer edge of the absorbent body has a rear curved portion that is connected to a longitudinal rear end of the absorbent body and extends along the inward convex curved portion of the outer edge of the flap portion. The absorbent article according to any one of claims 1 to 4 , wherein an outer edge of the side flap portion has a rear constricted portion in the rear region, the rear constricted portion being located forward of the rear convex portion in the longitudinal direction and connected to the rear convex portion. The absorbent article according to claim 5 , wherein the outer edges of the side flaps have a front constriction in the front region. 7. The absorbent article according to claim 6, wherein in a region overlapping with the absorbent body in a planar view, an inter-constriction region located between the rear constriction and the front constriction in the longitudinal direction has higher compression recovery than a region adjacent to the inter-constriction region in the longitudinal direction. The absorbent article according to any one of claims 1 to 7, wherein a pair of rear convex portions is present in the rearmost region when the absorbent article is divided into three equal parts in the longitudinal direction, and the length in the lateral direction of the rearmost region is the longest between the pair of rear convex portions.