Absorbent pad

Abstract

This absorbent pad 1 comprises: a surface layer (2) that has protruding sections (21) protruding toward the skin side and recess sections (22) each having an open hole (23) in the bottom; a gap forming layer (4) that is composed of a liquid-permeable member, has protruding sections protruding toward the skin side and recess sections that include internal spaces (S3), and forms, between the gap forming layer (4) and the surface layer (2), an excreta dispersion space (V) that causes excreta supplied via the open holes to be dispersed in a direction intersecting the thickness direction of the absorbent pad; and a drawing-in layer (5) that is formed from a fiber assembly (5A), has portions (50) that enter into the internal space (S3), and draws in a low-viscosity component from the excreta in the excreta dispersion space (V).

Description

Absorbent pad

[0001] The present invention relates to an absorbent pad.

[0002] Studies have been conducted on the treatment and retention of liquid feces with respect to constituent members of absorbent articles such as diapers. For example, Patent Document 1 discloses an absorbent article including: a top sheet that allows liquid feces and the like to permeate and faces the skin; an absorbent body that retains liquid feces and the like; a second sheet interposed between the top sheet and the absorbent body, which allows liquid feces and the like to permeate and covers an outer surface of the absorbent body; a liquid feces-impermeable sheet located on the non-skin-contacting side of the absorbent body and covering the outer surface of the absorbent body; and a back sheet that covers the outer side of the liquid feces-impermeable sheet and serves as the non-skin-contacting surface of the absorbent article.

[0003] Japanese Unexamined Patent Publication No. 2021-045393

[0004] The present invention relates to an absorbent pad comprising a surface layer having convex portions protruding toward the skin side and concave portions having an opening at the bottom. In one embodiment, it is preferable that the absorbent pad comprises a gap-forming layer made of a liquid-permeable member, which has convex portions protruding toward the skin side and having an internal space, and concave portions, and forms a feces diffusion space between the gap-forming layer and the surface layer, the feces diffusion space diffusing feces supplied through the opening in a direction intersecting the thickness direction of the absorbent pad. In one embodiment, it is preferable that the absorbent pad further comprises a drawing layer formed of a fiber aggregate, the drawing layer having a portion entering the internal space and drawing a low-viscosity component from the feces in the feces diffusion space.

[0005] The present invention also relates to an absorbent article comprising the absorbent pad described above and a diaper used by overlapping the absorbent pad on the skin-facing surface side.

[0006] Figure 1 is a schematic plan view of one embodiment of the absorbent pad of the present invention, viewed from the skin-facing side. Figure 2 is a schematic enlarged cross-sectional view along the line I-I in Figure 1. Figure 3 is a schematic enlarged perspective view of the main part of the uneven sheet constituting the surface layer of the absorbent pad shown in Figure 1. Figure 4 is a schematic enlarged cross-sectional view of the main part of the uneven sheet shown in Figure 3. Figure 5 is a schematic enlarged perspective view of the main part of the uneven sheet constituting the gap-forming layer of the absorbent pad shown in Figure 1. Figure 6 is a schematic enlarged cross-sectional view of the main part of the uneven sheet shown in Figure 5. Figures 7(a) and (b) are explanatory diagrams of the absorption mechanism of the absorbent pad of the present invention. Figures 8(a) and (b) are explanatory diagrams of the absorption mechanism of the absorbent pad of the present invention. Figures 9(a) and (b) are explanatory diagrams of the absorption mechanism of the absorbent pad of the present invention. Figure 10 is an enlarged perspective view of the main part showing the surface layer and gap-forming layer of another embodiment of the absorbent pad of the present invention. Figure 11 is a schematic cross-sectional view along the thickness direction of another embodiment of the absorbent pad of the present invention. Figure 12 is a schematic cross-sectional view along the thickness direction of another embodiment of the absorbent pad of the present invention. Figure 13 is a schematic plan view of another embodiment of the absorbent pad of the present invention as seen from the skin-facing side. Figure 14 is a diagram corresponding to Figure 2 of another embodiment of the absorbent pad of the present invention. Figure 15 is an explanatory diagram of the absorption mechanism of the absorbent pad shown in Figure 14. Figure 16 is an explanatory diagram of the absorption mechanism of the absorbent pad shown in Figure 14. Detailed description of the invention

[0007] Absorbent articles such as diapers and absorbent pads generally have an absorbent core as the main part that absorbs excrement. The absorbent core generally contains absorbent materials such as fluff pulp or absorbent polymers, but in such cases, high viscosity or solid components contained in liquid stool may not be absorbed by the absorbent core and remain on the sheet or other material located on the skin side of the absorbent core, causing clogging between the fibers of the sheet and reducing the liquid absorption performance of the absorbent article. In absorbent articles equipped with such an absorbent core, when stool containing a large amount of high viscosity or solid components is discharged, rapid absorption of the stool may not be possible. The absorbent article described in Patent Document 1 did not consider the case when stool containing a large amount of high viscosity or solid components is discharged, and there was room for improvement.

[0008] Therefore, the present invention relates to an absorbent pad that can quickly absorb stool even when stool containing high viscosity or a large amount of solid components is expelled.

[0009] The present invention will be described below with reference to the drawings, based on preferred embodiments thereof. Figure 1 shows an absorbent pad 1, which is one embodiment of the present invention. The absorbent pad 1 of this embodiment has a horizontal direction Y and a vertical direction X perpendicular thereto, and is preferably used by overlapping it with the skin-facing surface (inner surface) of an absorbent article such as a diaper, with the direction extending from the wearer's abdominal side through the groin area to the back aligned with the vertical direction X. That is, the absorbent pad is preferably used in combination with an absorbent article such as a diaper as an inner layer, and is used to absorb and hold feces.

[0010] In this specification, the "skin-facing side" of an absorbent pad refers to the side of the absorbent pad or its components that faces the wearer's skin when the absorbent pad is worn, i.e., the side that is relatively closer to the wearer's skin. The "non-skin-facing side" of an absorbent pad refers to the side of the absorbent pad or its components that faces away from the skin (towards the clothing) when the absorbent pad is worn, i.e., the side that is relatively further away from the wearer's skin. Here, "when worn" means the normal and proper wearing position, i.e., the state in which the correct wearing position of the absorbent pad is maintained.

[0011] As shown in Figure 2, the absorbent pad 1 comprises a retaining layer 3 and a surface layer 2 that covers one side of the retaining layer 3. In this embodiment, the surface layer 2 covers one side of the retaining layer 3 and forms the skin-facing surface. The surface layer 2 has convex portions 21 that protrude toward the skin-facing surface and recesses 22 that have openings 23 at their bottoms 22T. More specifically, as shown in Figures 3 and 4, the surface layer 2 is composed of an uneven sheet 2A with an uneven structure, which has a plurality of convex portions 21 that protrude toward the skin-facing surface and have an internal space S1, and a plurality of recesses 22 that protrude toward the non-skin-facing surface and have an internal space S2 and openings at their bottoms.

[0012] When the surface layer 2 is viewed from above, it is preferable that the convex portions 21 and concave portions 22 are arranged alternately and continuously along two different directions that intersect each other. Here, it is preferable that the two different directions are such that an arbitrary first direction in the plane and the intersecting second direction intersect at an angle of 30 degrees or more and 90 degrees or less. For example, in the surface layer 2 of this embodiment, they intersect at 90 degrees. That is, for example, in the absorbent pad 1, one of the two directions is the transverse direction Y1, and the other of the two directions is the vertical direction X1. Therefore, when the uneven sheet 2A is viewed from above, the convex portions 21 and concave portions 22 are arranged alternately and continuously along the vertical direction X1 and the transverse direction Y1. In the configuration shown in Figure 3, the convex portions viewed from the skin-facing side are the convex portions 21, and the concave portions are the concave portions 22. Conversely, the convex portions viewed from the non-skin-facing side are the concave portions 22, and the concave portions are the convex portions 21.

[0013] In the absorbent pad 1, the uneven sheet 2A of the surface layer 2, as shown in Figures 3 and 4, has a wall portion 21W between its top portion 21T and the opening 21H of its internal space S1. Similarly, the recessed portion 22 has a wall portion 22W between its bottom portion 22T and the opening 22H of its internal space S2. The bottom portion 22T of the multiple recessed portions 22 has a lower fiber density than its surrounding portion and has an opening 23. In this embodiment, all of the multiple recessed portions 22 have an opening 23, but some of the multiple recessed portions 22 may have an opening 23. When some of the multiple recessed portions 22 have an opening 23, the uneven sheet 2A has recessed portions 22 that have both a bottom portion 22T with a penetrating opening 23 and a bottom portion 22T that does not have an opening 23 and has a lower fiber density than its surrounding portion. If some of the multiple recesses 22 have openings 23, it is preferable that the recesses 22 having openings 23 are uniformly distributed in a plan view of the uneven sheet 2A. The protrusions 21 of the surface layer 2 may be solid and not have an internal space S1.

[0014] The protrusions 21 and recesses 22 of the uneven sheet 2A are as follows: the protrusion of the protrusion 21 is hemispherical, while the protrusion of the recess 22 is a cone or frustocone shape with a rounded base. However, the protrusion shapes of the protrusions 21 and recess 22 are not limited to the above shapes and can be any shape. For example, they may be conical shapes such as a cone, frustocone, pyramidal pyramid, frustocone, or oblique cone.

[0015] Preferably, the uneven sheet 2A having convex portions 21 and concave portions 22 does not have any bent portions and is composed of a continuous curved surface throughout. Here, "continuous" means that there are no discontinuous portions or small holes other than the openings 23 formed at the bottom 22T of the concave portions 22. However, micropores such as gaps between fibers are not included in the small holes.

[0016] As the textured sheet 2A, any liquid-permeable sheet conventionally used in the art can be used without particular limitation. Examples of the textured sheet 2A include paper such as tissue paper, fiber sheets such as hydrophilic nonwoven fabrics (spunbond nonwoven fabrics, spunlace nonwoven fabrics, etc.), and films. The textured sheet 2A is preferably liquid-permeable and hydrophilic, as described above. The method for manufacturing the textured sheet 2A having openings is not particularly limited. For example, when manufacturing a nonwoven fabric by the water flow entanglement method, fiber fibers are placed on a net having an uneven surface, and a water flow is applied to the extent that openings are created in the parts located at the tops of the protrusions to obtain a nonwoven fabric having openings. The obtained nonwoven fabric is then inverted so that the parts with openings are located at the bottom of the recesses 22, and used as the textured sheet 2A having openings 23.

[0017] The absorbent pad 1 comprises a surface layer 2, a gap-forming layer 4, and a retraction layer 5, arranged in this order from the skin-facing side to the non-skin-facing side. Note that in some figures, for ease of explanation, the surface layer 2 and the gap-forming layer 4 are depicted as separated, but in reality, they are in partial contact. In the absorbent pad 1, the surface layer 2 forms the skin-facing surface, and the retention layer 3 is the part that absorbs and retains excrement. As shown in Figure 2, the retention layer 3 has a laminated structure in which the gap-forming layer 4, the retraction layer 5, the diffusion layer 6, and the absorbent layer 7 are stacked in this order from the skin-facing side to the non-skin-facing side. The names "gap-forming layer," "retraction layer," "diffusion layer," and "absorbent layer" indicate their functional characteristics. It is preferable that the absorbent pad 1 has a leak-proof layer 8 on the non-skin-facing side. The leak-proof layer 8 can be formed from a liquid-impermeable sheet. Liquid impermeability includes low liquid permeability, and low liquid permeability sheets also include sheets formed using moisture-permeable films, etc.

[0018] The gap-forming layer 4 is adjacent to the surface layer 2 in the thickness direction of the absorbent pad 1. The gap-forming layer 4 is a part that plays a role in forming a stool diffusion space V, which will be described later, between the surface layer 2 and the gap-forming layer 4. The gap-forming layer 4 has an uneven structure in order to form a gap that becomes the stool diffusion space V between it and the surface layer 2. Specifically, in this embodiment, the gap-forming layer 4 is composed of an uneven sheet 4A having an uneven structure that includes a convex portion 41 that protrudes toward the skin-facing surface and has an internal space S3, and a concave portion 42 that protrudes toward the non-skin-facing surface and has an internal space S4, similar to the surface layer 2. When the gap-forming layer 4 is viewed from above, the uneven sheet 4A is arranged alternately and continuously along two different directions in which the convex portion 41 and concave portion 42 intersect each other (see Figures 5 and 6). The uneven sheet 4A is a component that is also called a second sheet or sub-layer sheet in this art.

[0019] As the textured sheet 4A, a liquid-permeable material can be used. Examples of such sheets include nonwoven fabrics (spunbond nonwoven fabrics, spunlace nonwoven fabrics, etc.), urethane sheets, etc. One of these can be used alone, or two or more can be used in combination.

[0020] In the absorbent pad 1 of the present invention, a stool diffusion space V is formed between the surface layer 2 and the gap-forming layer 4 (see Figure 2). The stool diffusion space V is a part that plays a role in diffusing the stool supplied through the opening 23 in a direction intersecting the thickness direction Z. From the viewpoint of forming a stool diffusion space V with excellent stool diffusion properties, as described above, it is preferable that the gap-forming layer 4 is adjacent to the surface layer 2 in the thickness direction of the absorbent pad 1, and at least a part of it is in contact with the surface layer 2. In particular, from the viewpoint of more reliably securing the stool diffusion space V, it is preferable that, for example, the surface layer 2 and the gap-forming layer 4 overlap in a state in which the recesses 22 of the surface layer 2 and the protrusions 41 of the gap-forming layer 4 are in contact. The stool diffusion space V is a space in which the internal space S1 of the protrusions 21 in the uneven sheet 2A and the internal space S4 of the recesses 42 in the uneven sheet 4A are in communication. More specifically, the stool diffusion space V is a space in which the internal space S1 of the protrusions 21 and the internal space S4 of the recesses 42 are continuous in the planar direction. The fecal diffusion space V is preferably formed continuously around the entire perimeter of a single recess 22 in the uneven sheet 2A, and it is preferable that the space surrounding each recess 22 is in communication with the spaces surrounding other recesses 22. Furthermore, the fecal diffusion space V is preferably formed continuously around the entire perimeter of a single protrusion 41 in the uneven sheet 4A, and it is preferable that the space surrounding each protrusion 41 is in communication with the spaces surrounding other protrusions 41. The fecal diffusion space V has little to no constituent material of the uneven sheet 2A and the uneven sheet 4A. Here, "little to no" means that ideally, each constituent material is not present at all, but it does not exclude the possibility that some of each constituent material may be present due to fuzzing, damage, etc.

[0021] The retraction layer 5 is located on the non-skin-facing side of the gap-forming layer 4 in the thickness direction Z and is adjacent to the gap-forming layer 4. The retraction layer 5 has the role of separating the low-viscosity components contained in the stool from the stool in the stool diffusion space V. The low-viscosity components are the parts of the stool, especially liquid stool, that have had the high-viscosity and solid components removed, and are the highly fluid parts that contain a lot of water. From the viewpoint of making it easier to retract the low-viscosity components of the stool into the retraction layer 5 without letting them remain in the gap-forming layer 4, it is preferable that the inter-fiber distance of the fiber aggregate 5A constituting the retraction layer 5 is smaller than that of the uneven sheet 4A constituting the gap-forming layer 4. It is also preferable that the hydrophilicity of the fiber aggregate 5A constituting the retraction layer 5 is higher than that of the uneven sheet 4A constituting the gap-forming layer 4. From the viewpoint of improving the retractability of the low-viscosity components of the stool, it is preferable that the fiber aggregate 5A contains hydrophilic fibers. It is preferable that the constituent fibers constituting the fiber aggregate 5A do not have joints with each other. Using such a fiber aggregate 5A increases the degree of freedom of movement of the constituent fibers, making it possible to deform to conform to the shape of the internal space S3 of the uneven sheet 4A. Preferably, the fiber aggregate 5A constituting the pull-in layer 5 is made of, for example, flap pulp (cotton-like pulp), a stack of short fibers made of synthetic fibers, and a tow (fiber bundle) made of synthetic or semi-synthetic long fibers such as cellulose acetate. Preferably, these do not have bonds between constituent fibers that are bonded together by fusion, binders, etc. As the fiber aggregate 5A, a nonwoven fabric that does not have the above-mentioned bonds or a nonwoven fabric with weak constraints between fibers, such as a spunlace nonwoven fabric, can also be used. From the viewpoint of improving the pull-in of low-viscosity components of stool, it is preferable to use flap pulp as the fiber aggregate 5A.

[0022] Examples of fibers included in the fiber aggregate 5A include natural fibers such as wood pulp (coniferous pulp, hardwood pulp, etc.) and non-wood pulp (cotton pulp, hemp pulp, etc.); modified pulp (cationic pulp, mercerized pulp, etc.); regenerated cellulose fibers (all cellulose fibers) such as rayon and cupro; hydrophilic synthetic fibers such as polyvinyl alcohol fibers and polyacrylonitrile fibers; and synthetic fibers such as polyethylene fibers, polypropylene fibers, and polyester fibers that have been hydrophilized with a hydrophilizing agent such as a surfactant. One of these can be used alone or two or more can be used in combination. The content of hydrophilic fibers in the fiber aggregate 5A is not particularly limited, but is preferably 80% by mass or more of the total mass of the fiber aggregate 5A, and preferably 100% by mass, i.e., the fiber aggregate 5A is composed only of hydrophilic fibers. Furthermore, from the viewpoint of more smoothly transferring the low-viscosity components contained in the stool to the diffusion layer 6, it is preferable that the fiber aggregate 5A does not contain absorbent polymers. In this context, "free of absorbent polymers" means substantially free of absorbent polymers, and that the mass percentage of absorbent polymers is less than 10% of the weight of the indentation layer 5.

[0023] As shown in Figure 2, the fiber aggregate 5A in this embodiment has a portion 50 that extends into the internal space S3 of the uneven sheet 4A. Having this extended portion 50 increases the contact area between the uneven sheet 4A and the fiber aggregate 5A compared to when they are in contact on a flat surface, thus enabling the draw-in of low-viscosity components contained in the stool into the draw-in layer 5 more quickly. From this viewpoint, the height h1 of the portion 50 of the fiber aggregate 5A that extends into the internal space S3 of the uneven sheet 4A (hereinafter also referred to as the portion inside the protrusion 50) is preferably 50% or more, more preferably 80% or more, and even more preferably 100%, that is, the height T inside the protrusion 41 and the height h1 of the portion inside the protrusion 50 are approximately the same. As shown in Figure 2, the height h1 of the inner portion 50 of the protrusion is the distance from the recess 42 to the top of the inner portion 50 of the protrusion, and the height T of the inside of the protrusion 41 is the distance from the non-skin-facing side of the recess 42 to the non-skin-facing side of the top 41T of the protrusion 41.

[0024] The internal height T of the protrusion 41 is preferably 0.5 mm to 10 mm, and more preferably 0.7 mm to 8 mm. The internal height h1 of the protrusion portion 50 is preferably 0.4 mm to 8 mm, and more preferably 0.6 mm to 6 mm.

[0025] The diffusion layer 6 is the part that plays the role of diffusing the low-viscosity components of the stool supplied via the draw-in layer 5 in a direction intersecting the thickness direction Z of the layer. The diffusion layer 6 is adjacent to the draw-in layer 5. The diffusion layer 6 is composed of a diffusion sheet 6A. In this embodiment, the non-skin-facing side of the diffusion sheet 6A constituting the diffusion layer 6 has an extension that extends outward in the lateral direction Y from the non-skin-facing side of the absorption layer 7, and this extension is rolled up towards the skin-facing side to cover the skin-facing side of the absorption layer 7 (not shown). The diffusion sheet 6A may be composed of two sheets, in which case one diffusion sheet 6A covers the entire non-skin-facing side of the absorption layer 7, and the other diffusion sheet 6A covers the entire skin-facing side of the absorption layer 7 and extends outward from both side edges in the lateral direction Y of the absorption layer 7, and this extension may be rolled down towards the non-skin-facing side of the absorption layer 7 and overlap with the other diffusion sheet 6A.

[0026] The diffusion sheet 6A is preferably arranged to cover the entire lateral Y area of ​​at least the skin-facing side of the absorbent layer 7, and more preferably to cover the entire skin-facing and non-skin-facing sides of the absorbent layer 7. With this configuration, the low-viscosity components of the stool can be quickly transferred to the absorbent layer 7.

[0027] From the viewpoint of reliably achieving the above functions, fiber sheets and urethane sheets are preferably used as the diffusion sheet 6A. As fiber sheets, thin paper such as tissue paper and nonwoven fabrics such as spunbond-meltblown-spunbond (SMS) nonwoven fabrics are preferably used. As urethane sheets, porous materials are used, and for example, it is preferable to use urethane foam with open cells so that the low viscosity components of stool can diffuse inside.

[0028] The absorption layer 7 is adjacent to the diffusion layer 6. The absorption layer 7 is responsible for absorbing the low-viscosity components diffused in the diffusion layer 6. The absorption layer 7 can contain a superabsorbent polymer. For example, the absorption layer 7 may consist of a superabsorbent polymer, or it may be composed of a mixed layer of hydrophilic fibers such as pulp fibers and a superabsorbent polymer.

[0029] As the superabsorbent polymer contained in the absorbent layer 7, a hydrogel material capable of absorbing and retaining water can generally be used, for example, polymers or copolymers of acrylic acid or alkali metal acrylate salts can be used. Examples include polyacrylic acid and its salts, and polymethacrylic acid and its salts, and specifically, partially sodium salts of acrylic acid polymers. The shape of the superabsorbent polymer is not particularly limited and can be spherical, tufted, lumpy, barrel-shaped, fibrous, irregularly shaped, or a combination thereof. If the absorbent layer 7 contains hydrophilic fibers, examples of hydrophilic fibers include pulp fibers, rayon fibers, cotton fibers, cellulose acetate, and other cellulose-based fibers. In addition to cellulose-based hydrophilic fibers, fibers made of synthetic resins such as polyolefins, polyesters, and polyamides that have been made hydrophilic with surfactants can also be used.

[0030] As described above, the absorbent pad 1 of this embodiment is preferably used in conjunction with absorbent articles such as diapers. That is, the wearer's excrement is excreted onto the absorbent pad 1. When stool (feces P) containing a large amount of high viscosity or solid components is excreted onto the absorbent pad 1, the feces P is smoothly absorbed into the absorbent pad 1. The mechanism of absorption in this invention will be explained in more detail. The space between the top 21T of the convex portion 21 and the bottom 22T of the concave portion 22 is an inclined surface, and even if the high viscosity or solid components of the feces P supplied from the skin-facing side are supplied near the top 21T of the convex portion 21, they are guided along the inclined surface to the concave portion 22 (see Figure 7(a)), and then move to the gap-forming layer 4 side through the opening 23 in the concave portion 22. After passing through the surface layer 2, the high-viscosity or solid components of the stool P reach the stool diffusion space V (see Figure 7(b)), where they are diffused laterally in the direction Y (see Figure 8(a)) and contained (see Figure 8(b)).

[0031] On the other hand, the low-viscosity components contained in the stool P rapidly migrate from the openings 23 in the recesses 22 to the stool diffusion space V, where they diffuse laterally in the lateral direction Y (see Figure 8(a)). The low-viscosity components of the stool P are then drawn into the inclusion layer 5 via the gap-forming layer 4 (see Figure 8(b)). In the inclusion layer 5, the low-viscosity components of the stool P diffuse into the interior of the fiber aggregate 5A and migrate to the diffusion layer 6. In the diffusion layer 6, they diffuse in a direction intersecting the thickness direction Z of the diffusion layer 6 (see Figure 9(a)), and rapidly migrate to the absorption layer 7 (see Figure 9(b)). The low-viscosity components are then incorporated into the absorption layer 7, which contains an absorbent polymer, and absorbed. In this way, the inclusion of high-viscosity or solid components of the stool P occurs mainly through a path centered on the openings 23, allowing for smooth inclusion of stool even when a large amount of high-viscosity or solid components are discharged. As a result, even in cases of multiple large bowel movements, for example, high-viscosity or solid components are incorporated and contained within the stool diffusion space V, effectively suppressing stool leakage.

[0032] As described above, in the absorbent pad 1 of this embodiment, when the surface layer 2 is viewed from above, the convex portions 21 and concave portions 22 are arranged alternately and continuously along two different directions that intersect each other. This arrangement allows high-viscosity or solid components contained in the stool to be guided into the concave portions 22 more quickly, enabling smooth absorption of the stool.

[0033] When the diffusion sheet 6A is composed of a fiber sheet, it is preferable that the diffusion sheet 6A be made of a nonwoven fabric in which the constituent fibers are entangled or bonded, from the viewpoint of rapidly diffusing the low-viscosity components of the stool in a direction intersecting the thickness direction Z of the layer. Specifically, it is preferable to use a backing such as tissue paper. Here, "entanglement" means a state in which the constituent fibers are sufficiently intertwined with each other, and a state in which the fiber layers are simply stacked on top of each other is not included in entanglement.

[0034] In the present invention, the pitch of the irregularities of the uneven sheet 2A constituting the surface layer 2 and the pitch of the irregularities of the uneven sheet 4A constituting the gap-forming layer 4 may be the same or different. In this embodiment, as shown in Figure 2, the pitch P2 of the irregularities of the uneven sheet 4A constituting the gap-forming layer 4 is finer than the pitch P1 of the irregularities of the uneven sheet 2A constituting the surface layer 2. More specifically, the pitch P2 of the uneven sheet 4A is smaller than the pitch P1 of the uneven sheet 2A. Pitch is the distance between the tops of adjacent protrusions or recesses, and if there are multiple protrusions or recesses around a protrusion or recess that are at different distances from that protrusion or recess, the pitch is the distance between the closest protrusion and recess. In the embodiment shown in Figure 2, the position of the recess 22 of the uneven sheet 2A and the position of the recess 42 of the uneven sheet 4A do not overlap in the thickness direction Z, and the position of the protrusion 21 of the uneven sheet 2A and the position of the protrusion 41 of the uneven sheet 4A do not coincide. By incorporating this configuration, the surface area of ​​the uneven sheet 4A is improved, and the space of the stool diffusion space V can be widened, allowing for smoother drawing in of high-viscosity or solid components and low-viscosity components of the stool. The difference in the pitch of the unevenness can be created during the manufacturing of the uneven sheet, for example, by adjusting the stretch ratio between the uneven sheet 2A and the uneven sheet 4A. Alternatively, a difference in the pitch of the unevenness can be created during manufacturing by widening one direction of the uneven sheet.

[0035] From the viewpoint of increasing the surface area of ​​the gap-forming layer 4 and improving the efficiency of drawing in low-viscosity components of stool, the ratio of pitch P1 to pitch P2 (P1 / P2) is preferably 1 or more, and more preferably 1.2 or more. If pitch P2 is too large, the number of recesses 42 decreases, which reduces the number of places where high-viscosity or solid components can be incorporated. Therefore, from the viewpoint of ensuring an appropriate number of recesses 42, the ratio of pitch P1 to pitch P2 (P1 / P2) is preferably 5 or less, and more preferably 4.5 or less. Taking the above into consideration, the ratio of pitch P1 to pitch P2 (P1 / P2) is preferably 1 or more and 5 or less, and more preferably 1.2 or more and 4.5 or less.

[0036] From the viewpoint of enabling the more rapid incorporation of low-viscosity components contained in stool, it is preferable that the diffusion sheet 6A constituting the diffusion layer 6 has a higher hydrophilicity than the fiber aggregate 5A constituting the incorporation layer 5. In this invention, "hydrophilicity" is an indicator of the contact angle of the constituent fibers of the sheet, measured by the method described below, and is determined based on the contact angle. Specifically, high hydrophilicity is synonymous with a small contact angle, and low hydrophilicity is synonymous with a large contact angle. Therefore, in the absorbent pad 1 of this embodiment, the relationship "contact angle of diffusion sheet 6A ≤ contact angle of fiber aggregate 5A" holds true. In this specification, "contact angle" refers to the contact angle measured by the method described below, unless otherwise specified. In this specification, if the contact angle is 90 degrees or less, the sheet is hydrophilic, and if the contact angle is greater than 90 degrees, the sheet is hydrophobic. The difference between the contact angle of the fiber aggregate 5A and the contact angle of the diffusion sheet 6A is preferably 5 degrees or more, more preferably 10 degrees or more, preferably 70 degrees or less, more preferably 65 degrees or less, and also preferably 5 degrees or more and 70 degrees or less, more preferably 10 degrees or more and 65 degrees or less. The contact angle of the fiber aggregate 5A is preferably 30 degrees or more, more preferably 40 degrees or more, preferably 100 degrees or less, more preferably 90 degrees or less, and more specifically, preferably 30 degrees or more and 100 degrees or less, and more preferably 40 degrees or more and 90 degrees or less. The contact angle of the diffusion sheet 6A is preferably 30 degrees or more, more preferably 40 degrees or more, preferably 95 degrees or less, more preferably 85 degrees or less, preferably 30 degrees or more and 95 degrees or less, and more preferably 40 degrees or more and 85 degrees or less.

[0037] <Method for Measuring Contact Angle> The fiber aggregate 5A and diffusion sheet 6A will be used as the measurement targets. A 10 mm x 10 mm rectangular shape will be cut out from the measurement targets to serve as a measurement sample, and the contact angle of water with respect to this sample will be measured. An automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. will be used as the measurement device. Deionized water will be used to measure the contact angle. The amount of liquid dispensed from the inkjet type water droplet ejection unit (CTC-25 pulse injector with an ejection unit pore diameter of 25 μm, manufactured by Cluster Technology Co., Ltd.) will be set to 20 picoliters, and water droplets will be dropped directly onto the fibers. The dropping process will be recorded on a high-speed recording device connected to a horizontally mounted camera. From the perspective of later image analysis, a personal computer with a built-in high-speed capture device is preferable as the recording device. In this measurement, images will be recorded every 17 msec. In the recorded video, the first image of a water droplet landing on the fiber is analyzed using the included FAMAS software (software version 2.6.2, analysis method: droplet method, analysis method: θ / 2 method, image processing algorithm: non-reflective, image processing image mode: frame, threshold level: 200, curvature correction: none), and the angle between the air-exposed surface of the water droplet and the fiber is calculated and defined as the contact angle. A measurement sample cut from the object to be measured is placed on the sample stand of the contact angle meter and kept horizontal. Two different contact angles are measured for each measurement sample. The contact angles of N=5 samples are measured to one decimal place, and the average value of the total 10 measured values ​​(rounded to two decimal places) is defined as the contact angle of the measurement sample with water. The measurement environment is room temperature 22±2℃ and humidity 65±2%RH. Furthermore, if the sheet to be measured is joined to other components by adhesive, fusion, or other means within the absorbent pad, the adhesive force should be removed from the joint by methods such as blowing cold air from a cold spray before removal. This method of removal from the absorbent pad can also be used for other measurements.

[0038] When the diffusion layer 6 is composed of a fiber sheet, it is preferable that the fiber sheet constituting the diffusion layer 6 has a smaller inter-fiber distance than the fiber aggregate 5A, from the viewpoint of enabling faster incorporation of low-viscosity components contained in the stool and further improving the absorbability of the low-viscosity components of the ingested stool. From the same viewpoint as above, the inter-fiber distance of the fiber aggregate 5A is preferably 10 μm or more, more preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less, preferably 10 μm or more and 100 μm or less, and more preferably 20 μm or more and 80 μm or less. From the same viewpoint as above, the inter-fiber distance of the fiber sheet constituting the diffusion layer 6 is preferably greater than 0 μm, more preferably 2 μm or more, preferably 80 μm or less, more preferably 60 μm or less, preferably greater than 0 μm and 80 μm or less, and more preferably 2 μm or more and 60 μm or less. The interfiber distance of the fiber aggregate 5A is preferably 1.2 times or more, more preferably 1.4 times or more, preferably 15 times or less, more preferably 13 times or less, and also preferably 1.2 times or more and 15 times or less, and more preferably 1.4 times or more and 13 times or less, compared to the interfiber distance of the fiber sheets constituting the diffusion layer 6. The interfiber distance is measured by the following method.

[0039] <Method for Measuring Interfiber Distance> The interfiber distance of fiber sheets, fiber assemblies, etc., is determined by the following formula (1) based on Wrotnowski's assumption. Formula (1) is generally used when determining the interfiber distance of fiber sheets, fiber assemblies, etc. Under Wrotnowski's assumption, the fibers are cylindrical, and each fiber is arranged regularly without intersecting. First, the interfiber distance in each fiber sheet constituting the fiber assembly 5A and the diffusion layer 6 is calculated using formula (1) below. In this case, the thickness t, basis weight W, fiber resin density ρ, and fiber diameter D used in formula (1) below are those for each fiber sheet constituting the fiber assembly 5A and the diffusion layer 6 to be measured. The thickness t, basis weight W, and fiber diameter D are the average values ​​of measurements at multiple measurement points. The thickness t (mm) is measured by the following method. The fiber sheets constituting the fiber assembly 5A and the diffusion layer 6 are the sheets to be measured. First, the sheet to be measured is cut into pieces measuring 50 mm in length and 50 mm in width to create a cut piece. However, if it is not possible to create a cut piece of this size from the sheet to be measured, the largest possible cut piece is created. Next, this cut piece is placed on a flat plate, and a flat glass plate is placed on top of it. Weights are evenly distributed on the glass plate so that the total load including the glass plate is 49 Pa, and the thickness of the cut piece is measured. The measurement environment is set to a temperature of 20 ± 2°C and a relative humidity of 65 ± 5%, and a microscope (VHX-1000, manufactured by Keyence Corporation) is used as the measuring instrument. To measure the thickness of the cut piece, first, a magnified photograph of the cut surface of the cut piece is obtained. Known dimensions are simultaneously captured in this magnified photograph. Next, a scale is aligned with the magnified photograph of the cut surface of the cut piece, and the thickness of each part of the sheet to be measured in the cut piece is measured. The above operation is performed three times, and the average value of the three measurements is taken as the thickness t of the sheet to be measured.

[0040] Basis weight W (g / m ２ The basis weight (G / m²) is determined by cutting the sheet to be measured to a predetermined size (e.g., 12 cm x 6 cm), measuring the mass, and then dividing the mass measurement by the area obtained from that predetermined size ("Basis weight W (g / m²)"). ２) = mass ÷ area determined from a given size). Repeat this measurement four times and the average value is taken as the basis weight. Fiber resin density ρ (g / cm³). ２ The fiber diameter D is measured using a density gradient tube in accordance with the measurement method of the density gradient tube method described in JIS L1015 Chemical Fiber Staple Test Method (URL: http: / / kikakurui.com / l / L1015-2010-01.html, or in book form, JIS Handbook Fibers-2000, (Japanese Standards Association), pp. 764-765). The method for measuring the fiber diameter D follows the <Method for Measuring Fiber Diameter> described below.

[0041]

[0042] <Method for Measuring Fiber Diameter> The sheet to be measured is cut with a razor (for example, a single-edged razor manufactured by Feather Safety Razor Co., Ltd.) to obtain a measurement piece with a rectangular shape in plan view (8 mm x 4 mm). When cutting the sheet to be measured, care should be taken to ensure that the structure of the cut surface of the measurement piece formed by the cutting is not damaged by the pressure during cutting. A preferred method for cutting the sheet to be measured is to freeze the sheet thoroughly in liquid nitrogen before cutting it. The measurement piece is attached to the sample stage using double-sided tape (Nichiban Co., Ltd. Nicetack NW-15). Next, the measurement piece is platinum coated. For coating, an ion sputtering device E-1030 (product name) manufactured by Hitachi Naka Seiki Co., Ltd. is used, and the sputtering time is 30 seconds. The cut surface of the measurement piece is observed at a magnification of 1000x using a Hitachi, Ltd. S-4000 field emission scanning electron microscope. For the constituent fibers of the sheet to be measured, the length of 10 fibers in the width direction relative to the longitudinal direction is measured, and the average value is taken as the fiber diameter.

[0043] When the sheet to be measured is a porous material, for example, a urethane sheet, the interfiber distance is defined as the pore diameter of the porous material. The pore diameter of the porous material is measured using the following method. The sheet to be measured is cut with a razor (for example, a single-edged razor manufactured by Feather Safety Razor Co., Ltd.) to obtain a rectangular piece (8 mm x 4 mm) in plan view. When cutting the sheet to be measured, care should be taken to ensure that the structure of the cut surface of the piece formed by the cutting is not damaged by the pressure during cutting. A preferred method for cutting the sheet to be measured is to freeze it thoroughly in liquid nitrogen before cutting. The piece to be measured is attached to the sample stage using double-sided tape (Nichiban Co., Ltd. Nicetack NW-15). Next, the piece to be measured is platinum coated. For coating, an ion sputtering device E-1030 (product name) manufactured by Hitachi Naka Seiki Co., Ltd. is used, and the sputtering time is 30 seconds. The cross-section of the sample is observed at a magnification of 1000x using a Hitachi S-4000 field emission scanning electron microscope. Ten porous pores are arbitrarily selected from the two-dimensional image, and their maximum span lengths are directly read. The arithmetic mean of these lengths is defined as the pore diameter of the porous material.

[0044] The uneven sheet 2A is designed so that even if the protrusions 21 are crushed by body pressure during wear and inward pressure from the wearer's thighs, the shape of the protrusions 21 recovers to its original shape, allowing excreted bodily fluids to be quickly absorbed into the absorbent material, suppressing the diffusion of excreted bodily fluids on the surface of the uneven sheet 2A, and suppressing the return of bodily fluids absorbed into the absorbent layer 7. From this viewpoint, the compressibility of the uneven sheet 2A of the surface layer 2 is preferably 5% or more, more preferably 10% or more, preferably 98% or less, more preferably 95% or less, preferably 10% to 95%, and more preferably 30% to 90%. The compressibility of the uneven sheet 2A can be measured using a KES compression tester. The larger the value measured using the KES compression tester, the better the cushioning performance can be evaluated. The compression ratio of the textured sheet 2A measured by the KES compression tester is specified in "Standardization and Analysis of Texture Evaluation (2nd Edition)" [by Sueo Kawabata, published by the Texture Measurement and Standardization Research Committee of the Textile Machinery Society of Japan (July 10, 1980)], and is a physical property related to the compression characteristics of the fabric. The method for measuring the compression ratio of the textured sheet 2A using the KES compression tester is as follows.

[0045] <Method for measuring the compressibility> A KES-FB3 compression tester manufactured by Kato Tech Co., Ltd. will be used as the measuring device. Using this tester, the compression area will be 2 cm². ２ The sample (surface layer 2, uneven sheet 2A) was 0.5 gf / cm². ２ The thickness T0 under load is measured. Next, the sample is compressed at a pressing rate of 20 μm / sec. The load increases as compression progresses. The compression load is 35 gf / cm. ２ Continue until it reaches 35 gf / cm². ２ The thickness Tm is measured under load. The value obtained by subtracting thickness Tm from thickness T0 is divided by thickness T0, and this is multiplied by 100 to calculate the compressibility (%) of the uneven sheet 2A of the surface layer 2 as measured by the compression testing machine. In other words, the compressibility (%) is calculated from (T0 - Tm) / T0 × 100.

[0046] The compression energy of the uneven sheet 2A is preferably 0.98 mN・m / cm, from the viewpoint of providing a pleasant feel against the skin when the protrusions 21 come into contact with the skin and allowing the protrusions 21 to follow the body's movements, due to the body pressure during wear and the inward pressing force from the wearer's thighs.２ or more, more preferably 3.43 mN·m / cm ２ or more, preferably 9.8 mN·m / cm ２ or less, more preferably 6.86 mN·m / cm ２ or less, preferably 0.98 mN·m / cm ２ or more and 9.8 mN·m / cm ２ or less, more preferably 3.43 mN·m / cm ２ or more and 6.86 mN·m / cm ２ or less is even more preferable. The compression energy of the uneven sheet 2A of the surface layer 2 can be measured using a KES compression tester. It can be evaluated that the larger the WC value measured using a KES compression tester is, the more easily the uneven sheet 2A is crushed. The method for measuring the compression energy of the uneven sheet 2A using a KES compression tester is as follows.

[0047] <Method for measuring compression energy> A KES-G5 handy compression tester manufactured by Kato Tech Co., Ltd. is used as the measuring device. Using this tester, a 5 cm × 10 cm sample (uneven sheet 2A) is prepared and attached to a test table. Next, the sample is placed on an area of 2 cm ２ and compressed between steel plates having a circular plane. The compression speed is 20 μm / sec, and the maximum compression load is 4.9 kPa. Measurement is also performed at the same speed during the recovery process. The compression energy (WC) of the uneven sheet 2A is represented by the following formula. Tm, T0 and P are respectively 3.43 kPa (35 gf / cm ２ ) thickness under load, 49 Pa (0.5 gf / cm ２ ) the thickness under load and the load during measurement.

[0048]

[0049] Next, preferred configurations and other details of each embodiment described above will be elaborated. From the viewpoint of further improving the ability to absorb high viscosity or solid components contained in stool and making it easier for high viscosity or solid components contained in stool to pass through, the size of the opening 23, i.e., the opening width, is preferably 0.2 mm or more, more preferably 0.5 mm or more, also preferably 5.0 mm or less, more preferably 4.8 mm or less, also preferably 0.2 mm or more and 5.0 mm or less, more preferably 0.5 mm or more and 4.8 mm or less. The opening 23 is a portion with a lower fiber density than the surrounding area of ​​the recess 22.

[0050] The fiber density around the bottom portion 22T is preferably 120 fibers / mm², from the viewpoint of making it less likely to collapse under high load and reducing the amount of liquid return. ２ The above is a more precise 150 lines / mm ２ The above is preferable, with a preferred value of 500 threads / mm ２ More preferably, 450 strands / mm ２ Preferably, 120 strands / mm ２ 500 pieces / mm or more ２ More preferably, 120 strands / mm ２ 450 pieces / mm ２ More preferably, 150 strands / mm ２ 330 pieces / mm ２ The following applies: From the viewpoint of further improving the uptake of high-viscosity or solid components contained in stool and facilitating the passage of high-viscosity or solid components contained in stool, the fiber density of the opening 23 is preferably 0 fibers / mm². ２ Above, a comfortable rate of 20 strands / mm ２ The above is preferable, preferably 180 strands / mm ２ More preferably, 150 strands / mm ２ Preferably, 0 strands / mm ２ 180 pieces / mm ２ More preferably 0 lines / mm ２ 150 pieces / mm ２ More preferably, the number of strands per mm is 20. ２ 150 pieces / mm ２ The following applies: Fiber density is 1 mm ２The evaluation was performed by measuring the number of fibers per unit area. The method for measuring fiber density is as follows:

[0051] <Measurement of Fiber Density> The uneven sheet 2A was cut, and the cut surface was observed under magnification using a scanning electron microscope. The cross-sectional area of ​​the fibers cut per unit area of ​​the cut surface was counted. The magnification was adjusted to a level (150x to 500x) that allowed for the measurement of approximately 30 to 60 fiber cross-sections. Next, 1 mm ２ Convert this to the number of fiber cross-sections per unit area, and use this as the fiber density (fibers / mm²). ２ The fiber density of each sample was measured at three locations and averaged. The scanning electron microscope used was the JCM-5100 (product name) manufactured by JEOL Ltd.

[0052] From the viewpoint of further improving the ability to draw in low-viscosity components contained in stool, the basis weights of the uneven sheet 4A, the fiber aggregate 5A, and the diffusion sheet 6A are preferably within the following ranges. The basis weight of the uneven sheet 4A is preferably 15 g / m². ２ Above, a comfortable 20 g / m² ２ The above is preferable, and more preferably 70 g / m ２ More preferably, 65 g / m ２ The following is also preferred: 15 g / m² ２ 70g / m or more ２ More preferably, 20 g / m ２ 65g / m or more ２ The following applies: The basis weight of the fiber aggregate 5A is preferably 100 g / m². ２ More comfortably, 120 g / m² ２ The above is true, and preferably 400 g / m² ２ More preferably, 350 g / m ２ The following, and more preferably 100 g / m² ２ More than 400g / m ２ More preferably, 120 g / m² ２ 350g / m or more ２ The following applies: The basis weight of the diffusion sheet 6A is preferably 8 g / m². ２ More preferably, 10 g / m ２ The above is preferable, and more preferably 20 g / m ２More preferably, 18 g / m ２ The following is also preferred: 8 g / m ２ 20g / m or more ２ More preferably, 10 g / m ２ 18g / m or more ２ The following applies:

[0053] In the absorbent pad 1, the spaces between the uneven sheet 2A and the uneven sheet 4A, between the uneven sheet 4A and the fiber aggregate 5A, between the fiber aggregate 5A and the diffusion sheet 6A, and between the diffusion sheet 6A and the absorbent layer 7 are fixed by applying an adhesive, for example. The adhesive can be applied using known means, such as a slot coat gun, spiral spray gun, spray gun, or dot gun, and in the absorbent pad 1, it is preferable to apply it in a spiral manner using a spiral spray gun. As the adhesive to be applied, for example, a hot melt adhesive is preferably used. The amount of hot melt adhesive to be applied is 0.5 g / m². ２ 50g / m or more ２ The following is preferable:

[0054] The absorbent pad of the present invention is not limited to the embodiments shown in Figures 1 to 9 described above. Another embodiment of the absorbent pad according to the present invention will be described below. In the following, the components of the other embodiment will be described mainly in terms of components that differ from those of the embodiments shown in Figures 1 to 9, and similar components will be denoted by the same reference numerals and their description will be omitted. For components that are not specifically described, the description of the embodiments shown in Figures 1 to 9 will be applied as appropriate.

[0055] Figure 14 is a cross-sectional view showing another embodiment of the absorbent pad. The absorbent pad 1a of this embodiment, like the absorbent pad 1 of the embodiment described above, comprises a surface layer 2, a gap-forming layer 4, and a retraction layer 5 in this order from the skin-facing side to the non-skin-facing side. In the absorbent pad 1 of the embodiment described above, the convex portions 41 of the uneven sheet 4A constituting the gap-forming layer 4 did not have openings at the top portions 41T, but in the absorbent pad 1a, the convex portions 41 of the uneven sheet 4B constituting the gap-forming layer 4 have openings 44 at the top portions 41T. The method for manufacturing the uneven sheet 4B having openings is not particularly limited. For example, when manufacturing a nonwoven fabric by the water flow entanglement method, fiber febs are placed on an uneven net, and a water flow is applied to the extent that openings are created in the portions located at the tops of the convex portions to obtain a nonwoven fabric having openings. The obtained nonwoven fabric is used as an uneven sheet 4B having openings 44, such that the portion where the opening occurs is located at the top 41T of the protrusion 41. In the absorbent pad 1a of this embodiment, all of the multiple protrusions 41 have openings 44, but some of the multiple protrusions 41 may have openings 44. From the viewpoint of further suppressing fecal leakage, the ratio of the number of protrusions having openings 44 to the total number of protrusions 41 is preferably 10% or more and 100% or less, more preferably 15% or more and 95% or less. When some of the multiple protrusions 41 have openings 44, it is preferable that the protrusions 41 having openings 44 are uniformly distributed in a plan view of the uneven sheet 4B.

[0056] The absorbent pad 1a of this embodiment is preferably used on top of an absorbent item such as a diaper. That is, the wearer's excrement is excreted onto the absorbent pad 1a. Since the absorbent pad 1a has the same layer structure as the embodiment described above, when feces P are excreted onto the absorbent pad 1a, the feces P are smoothly absorbed into the absorbent pad 1a by a mechanism substantially the same as that of the absorbent pad 1. Specifically, when feces P are excreted onto the absorbent pad 1a, the high viscosity or solid components of the feces P migrate from the openings 23 in the recesses 22 of the uneven sheet 2A to the gap-forming layer 4 side, and diffuse laterally in the feces diffusion space V and are contained within the feces diffusion space V. On the other hand, the low viscosity components of the feces P also migrate from the openings 23 in the recesses 22 to the gap-forming layer 4 side. Then, the low-viscosity components of the stool P migrate from the openings 44 in the protrusions 41 to the draw-in layer 5 (as indicated by the symbol A in Figure 15), or, similar to the absorbent pad 1 of the embodiment described above, they diffuse laterally in the stool diffusion space V and are drawn into the draw-in layer 5 via the gap-forming layer 4. After passing through the draw-in layer 5, the low-viscosity components of the stool P are taken into the absorbent layer 7 via the diffusion layer 6 and absorbed.

[0057] The advantages of having an opening 44 at the top 41T of the protrusion 41 of the uneven sheet 4B constituting the gap-forming layer 4 in the absorbent pad 1a of this embodiment are as follows. Since the absorbent pad 1a of this embodiment has an opening 44 at the top 41T of the protrusion 41, it can take in feces P without leaking out, even in the case of a large amount of localized defecation. Specifically, when there is a large amount of localized defecation, the low viscosity component of feces P may not be drawn into the draw-in layer 5 via the gap-forming layer 4, and feces may leak out. However, since an opening 44 is provided at the top 41T of the protrusion 41, the low viscosity component of feces P that could not be drawn in via the gap-forming layer 4 can be transferred from the opening 44 to the draw-in layer 5 (the state shown by the symbol B in Figure 15). As a result, the absorbent pad 1a can take in feces with less leakage.

[0058] Furthermore, since the absorbent pad 1a has an opening 44 at the top 41T of the convex portion 41, even if pressure is applied to the absorbent pad 1a, there is no risk of the stool absorbed by the absorbent pad 1a leaking out. Specifically, when pressure is applied to the absorbent pad 1a, the low-viscosity component of the stool P absorbed by the absorbent pad 1a may overflow from the opening 44. However, since the opening 44 is provided at the top 41T of the convex portion 41, even if the low-viscosity component of the stool P overflows from the opening 44, it can be guided to the recess 42 along the inclined surface between the top 41T of the convex portion 41 and the bottom 42T of the recess 42 (see Figure 16). As a result, the low-viscosity component can be moved back to the intake layer 5, so there is no risk of the stool P leaking out. In this way, by having an opening 44 at the top 41T of the convex portion 41 of the uneven sheet 4B, the absorbent pad 1a can smoothly absorb stool while further suppressing stool leakage.

[0059] From the viewpoint of further diffusing the feces contained in the feces diffusion space V in a direction intersecting the thickness direction Z, it is preferable that in the region where the surface layer 2 and the gap-forming layer 4 overlap, the total area of ​​the openings 23 in the surface layer 2 is greater than or equal to the total area of ​​the openings 44 in the gap-forming layer 4. Specifically, when the area and number of openings in the same area where the surface layer 2 and the gap-forming layer 4 overlap are measured and compared, it is preferable that the total area A1 of the openings 23 in the uneven sheet 2A is greater than or equal to the total area A2 of the openings 44 in the uneven sheet 4B, and it is more preferable that the total area A1 of the openings 23 in the surface layer 2 is greater than the total area A2 of the openings 44 in the gap-forming layer 4. From the viewpoint of promoting the diffusion of feces in a direction intersecting the thickness direction Z, the ratio (A1 / A2) of the total area A1 of the openings 23 in the uneven sheet 2A to the total area A2 of the openings 44 in the uneven sheet 4B is preferably 1 or more, more preferably 1.1 or more. From the viewpoint of achieving rapid intake of stool, the ratio (A1 / A2) of the total area A1 of the openings 23 in the uneven sheet 2A to the total area A2 of the openings 44 in the uneven sheet 4B is preferably 2 or less, and more preferably 1.8 or less.

[0060] For each of the textured sheet 2A and textured sheet 4B, the area is 100 cm². ２ The total area of ​​the openings is preferably as follows: The total area A1 of the openings 23 in the uneven sheet 2A is preferably 70 mm². ２ 9000mm or more ２ More preferably 300 mm ２ 6000mm or more ２ The following applies: The total area A2 of the openings 44 in the uneven sheet 4B is preferably 30 mm ２ 9000mm or more ２ More preferably 150 mm ２ 6000mm or more ２ The following applies: The total area A1 of the openings 23 and the total area A2 of the openings 44 can be adjusted by appropriately adjusting the pitch of the irregularities, the number of openings, the area of ​​the openings, etc. The total area of ​​the openings is measured by the following method.

[0061] <Method for measuring the total area of ​​openings> In a plan view of the absorbent pad, a 100 mm x 100 mm square area is cut out from the region where the uneven sheet 2A and the uneven sheet 4B overlap, and the uneven sheet 2A and the uneven sheet 2B within this region are used as the measurement piece. If a 100 mm x 100 mm measurement piece cannot be cut out, a measurement piece is cut out to create the largest possible area. Next, the measurement piece is placed on black paper or a jig, and an image is taken at 20x magnification using a KEYENCE VHX-6000 microscope to obtain an image of the observation field. The size of the observation field is 12 mm x 16 mm. The area of ​​the openings is determined using the captured image in the "Measurement / Scale Mode" for image processing within the VHX-6000. Specifically, "Maximum Area Measurement" is selected under "Special Measurement" in the Measurement / Scale Mode. The extraction target is the dark area. When the area corresponding to the recess 22 is enclosed with the mouse, the black area corresponding to the opening 23 is automatically colored, and the length and width of the maximum area, treated as a rectangle, are displayed in the software. The length and width are recorded, and the opening 23 within that rectangle is approximated as an ellipse, and the area of ​​one opening 23 is calculated as the area of ​​the ellipse. This operation is performed for all recesses 22 in one image, and the results are summed up to obtain the total area of ​​the openings 23 in the observation field. Five images are taken, and the total area of ​​the openings 23 is calculated for each of the five images using the method described above. From these five images, the average of the total area of ​​the openings 23 is obtained from the three images excluding the largest and smallest total area. From the ratio of the total area of ​​the openings 23 (the average of the three images) to the area of ​​the observation field, the total area of ​​the openings 23 located in a 100 mm x 100 mm square area in the plan view of the absorbent pad 1 is calculated and taken as the total area of ​​the openings 23 of the uneven sheet 2A. For example, if the ratio of the total area of ​​the openings 23 to the area of ​​the observation field is 5.0%, then the total area of ​​the openings 23 is 10,000 mm². ２ 5.0% of 500 mm ２The method for measuring the total area of ​​the uneven sheet 4B is the same as for measuring the total area A1 of the openings 23 of the uneven sheet 2A, except that the uneven sheet 2B located within the 100 mm x 100 mm square area cut out in the method for measuring the total area of ​​the uneven sheet 2A is used as the measurement piece. When capturing an image of the observation field, the side of the uneven sheet 4B with the openings 44 is positioned towards the black paper or jig when taking the image. When measuring a part of an absorbent pad, if the part to be removed is joined to another part with adhesive, the adhesive force should be removed from the joint by blowing cold air from a cold spray before removal.

[0062] It is preferable that the relationship in which the total area A2 of the openings 44 in the uneven sheet 4B is greater than the total area A1 of the openings 23 in the uneven sheet 2A, and more preferably the ratio (A1 / A2) is 1.1 or more, is established at least in the central region of the pad or the region facing the anus. Whether or not the above relationship is established in the central region of the pad or the region facing the anus is determined by cutting out a region where the uneven sheet 2A and the uneven sheet 4B overlap, preferably a square region of 100 mm x 100 mm in plan view, from the central region of the pad or the region facing the anus, and comparing the total area of ​​only the openings located within that region for both the openings 23 of the uneven sheet 2A and the openings 44 of the uneven sheet 4B. For the central region of the pad, the center point of the square region in plan view is taken as the center point of the pad in the vertical and horizontal directions. For the area opposite the anus, the center point of the square-shaped area in plan view is defined as the point where the distance from one end of the pad is 1 / 3 of the total length of the pad in the vertical direction, and where the horizontal length of the pad is bisected.

[0063] From the viewpoint of more smoothly incorporating stool, it is preferable that the area of ​​each opening 23 in the surface layer 2 and the area of ​​each opening 44 in the gap-forming layer 4 be approximately the same. Specifically, it is preferable that the area A3 of each opening 23 in the uneven sheet 2A and the area A4 of the opening 44 in the uneven sheet 4B be approximately the same. Here, "approximately the same" preferably means that the ratio (A3 / A4) of the area A3 of each opening 23 in the uneven sheet 2A to the area A4 of each opening 44 in the uneven sheet 4B is 0.8 or more and 1.2 or less, more preferably 0.9 or more and 1.1 or less, and even more preferably 1.0. The area A3 of each opening 23 in the uneven sheet 2A is preferably 2 mm ２ 200mm or more ２ More preferably 5 mm ２ 180mm or more ２ The following applies: The area A4 of each opening 44 in the uneven sheet 4B is preferably 2 mm ２ 200mm or more ２ More preferably 5 mm ２ 180mm or more ２ The area of ​​each opening is measured by the following method.

[0064] <Method for measuring the area of ​​individual openings> In the same manner as the method for measuring the total area of ​​openings described above, five images of a 12 mm x 16 mm observation field are acquired, and the total area of ​​openings is calculated for each image. From the three images excluding the one with the largest and smallest total area, the average value of the total area of ​​openings is obtained. From the three images, the average value of the number of openings contained in each image is calculated and taken as the average number of openings. The value obtained by dividing the average total area of ​​openings by the average number of openings is taken as the "area of ​​individual openings". The area A3 of individual openings 23 is measured using a measurement piece obtained from the uneven sheet 2A, and the area A4 of individual openings 44 is measured using a measurement piece obtained from the uneven sheet 4B.

[0065] The pitch P4 of the uneven sheet 4B was smaller than the pitch P3 of the uneven sheet 2A, but the pitch P4 of the uneven sheet 4B may be smaller (see Figure 14), or the pitch P3 of the uneven sheet 2A and the pitch P4 of the uneven sheet 4B may be the same. From the viewpoint of further diffusing the stool contained in the stool diffusion space V in a direction intersecting the thickness direction Z, it is preferable that in the absorbent pad 1a, the pitch of the unevenness of the uneven sheet 2A constituting the surface layer 2 is finer than the pitch of the unevenness of the uneven sheet 4B constituting the gap-forming layer 4. From this viewpoint, it is preferable that the ratio of the pitch P4 of the uneven sheet 4B to the pitch P3 of the uneven sheet 2A (P4 / P3), the pitch P3 of the uneven sheet 2A, and the pitch P4 of the uneven sheet 4B are within the following ranges. The ratio of pitch P3 to pitch P4 (P4 / P3) is preferably 1 to 5, and more preferably 1.2 to 4.5, assuming that pitch P4 is larger than pitch P3. Pitch P3 is preferably 2 mm to 20 mm, and more preferably 5 mm to 15 mm. Pitch P4 is preferably 2 mm to 20 mm, and more preferably 5 mm to 15 mm, assuming that pitch P4 is larger than pitch P3.

[0066] Although the present invention has been described above based on its preferred embodiments, the absorbent pads of the present invention are not limited in any way to the absorbent pads 1 and 1a of the above embodiments and can be modified as appropriate. For example, the uneven sheet 2A and uneven sheet 4A of the above-described form have a plurality of protrusions having internal spaces and a plurality of recesses having internal spaces, and when viewed from above, the protrusions and recesses are arranged alternately and continuously along two different directions that intersect each other. However, for example, as shown in Figure 10, sheets with an uneven structure in which protrusions having unidirectional striate internal spaces and recesses having unidirectional striate internal spaces are arranged alternately may be used as the uneven sheet 2A and uneven sheet 4A. In this case, as shown in Figure 10, the unidirectional striate protrusions 21 and unidirectional striate recesses 22 of the uneven sheet 2A may be arranged to intersect with the unidirectional striate protrusions 41 and unidirectional striate recesses 42 of the uneven sheet 4A.

[0067] Furthermore, although the height T1 of the protrusions 21 of the uneven sheet 2A and the height T2 of the protrusions 41 of the uneven sheet 4A were approximately the same in the above-described configuration, they may be different. For example, as shown in Figure 11, the height T1 of the protrusions 21 of the uneven sheet 2A may be higher than the height T1 of the protrusions 41 of the uneven sheet 4A. By doing so, it is possible to secure a wider stool diffusion space V and to make it more difficult for the stool contained in the stool diffusion space V to return to the skin. From the viewpoint of further achieving the above-described effects, the ratio of the height T2 of the protrusions 41 to the height T1 of the protrusions 21 (T2 / T1) is preferably 0.5 or more, and more preferably 0.6 or more. From the viewpoint of improving the draw-in efficiency of the draw-in layer 5, the ratio of the height T2 of the protrusions 41 to the height T1 of the protrusions 21 (T2 / T1) is preferably 3 or less, and more preferably 2.8 or less. Based on the above, the ratio of the height T2 of the protrusion 41 to the height T1 of the protrusion 21 (T2 / T1) is preferably 0.5 or more and 3 or less, and more preferably 0.6 or more and 2.8 or less. The height T1 of the protrusion 21 and the height T2 of the protrusion 41 are both the distance from the non-skin-facing side of the recess to the skin-facing side of the protrusion.

[0068] The height T1 of the protrusion 21 is preferably 0.5 mm or more and 10 mm or less, and more preferably 0.7 mm or more and 8 mm or less. The height T1 of the protrusion 41 is preferably 0.5 mm or more and 10 mm or less, and more preferably 0.7 mm or more and 8 mm or less.

[0069] Furthermore, in the absorbent pad 1 of the above-described embodiment, the pitch P2 of the uneven sheet 4A was smaller than the pitch P1 of the uneven sheet 2A, but the pitch P1 of the uneven sheet 2A may be smaller (see Figure 12), or the pitch P1 of the uneven sheet 2A and the pitch P2 of the uneven sheet 4A may be the same. Moreover, in the absorbent pad 1 of the above-described embodiment, the recesses 42 of the uneven sheet 4A constituting the gap-forming layer did not have openings, but the recesses 42 may have openings 43 (see Figure 12). Note that if the recesses 42 have openings 43, not all recesses 42 have openings 43. Furthermore, in the absorbent pad 1 of the above-described embodiment, the positions of the recesses 22 of the uneven sheet 2A and the recesses 42 of the uneven sheet 4A do not overlap in the thickness direction Z, and the positions of the protrusions 21 of the uneven sheet 2A and the protrusions 41 of the uneven sheet 4A do not coincide. However, the positions of the recesses 22 of the uneven sheet 2A and the recesses 42 of the uneven sheet 4A, and the positions of the protrusions 21 of the uneven sheet 2A and the protrusions 41 of the uneven sheet 4A may overlap. Also, as shown in Figure 13, the absorbent pads 1 and 1a may have slits (through holes) 26 that penetrate the gap-forming layer 4, the indentation layer 5, the diffusion layer 6, and the absorbent layer 7 in the thickness direction Z.

[0070] In the absorbent pad 1a of the above-described form, the opening 44 was provided only at the top 41T of the uneven sheet 4B, but openings may also be provided at locations other than the top 41T. For example, openings 43 may be provided in the recesses 42 of the uneven sheet 4B. In this case, it is preferable that the number of recesses 42 having openings 43 is less than the number of protrusions 41 having openings 44, and the ratio of the number of recesses 42 having openings 43 to the number of protrusions 41 having openings 44 is preferably 0 or more and 0.1 or less, more preferably 0 or more and 0.1 or less.

[0071] Further relating to the embodiments of the present invention described above, the following absorbent pad is disclosed: <1> An absorbent pad comprising: a surface layer having a convex portion projecting toward the skin and a recess having an opening at its bottom; a gap-forming layer made of a liquid-permeable material, having a convex portion projecting toward the skin and a recess having an internal space, and forming a stool diffusion space between itself and the surface layer, which diffuses stool supplied through the opening in a direction intersecting the thickness direction of the absorbent pad; and a retraction layer made of a fiber aggregate, having a portion that penetrates the internal space, which draws in low-viscosity components from the stool in the stool diffusion space.

[0072] <2> The absorbent pad according to <1>, wherein the protrusions of the gap-forming layer have openings at their tops. <3> The absorbent pad according to <2>, wherein in a region where the surface layer and the gap-forming layer overlap, the total area of ​​the openings in the surface layer is equal to or greater than the total area of ​​the openings in the gap-forming layer. <4> The absorbent pad according to any one of <1> to <3>, wherein the protrusions of the gap-forming layer have openings at their tops, and the area of ​​each opening in the surface layer is approximately the same as the area of ​​each opening in the gap-forming layer. <5> The absorbent pad according to any one of <1> to <4>, further comprising a diffusion layer that diffuses the low-viscosity component incorporated into the draw-in layer in a direction intersecting the thickness direction of the absorbent pad, and an absorbent layer that absorbs the low-viscosity component diffused by the diffusion layer. <6> The absorbent pad according to <5>, wherein, when the surface layer is viewed in plan view, the convex portions and concave portions of the surface layer are arranged alternately and continuously along two different directions that intersect each other.

[0073] <7> The absorbent pad according to <5> or <6>, wherein the member constituting the diffusion layer has a higher hydrophilicity than the fiber aggregate constituting the inclusion layer. <8> The absorbent pad according to any one of <5> to <7>, wherein the diffusion layer is composed of a fiber sheet, and the inter-fiber distance of the fiber sheet is smaller than that of the fiber aggregate constituting the inclusion layer. <9> The absorbent pad according to any one of <5> to <8>, wherein the absorbent layer contains a superabsorbent polymer. <10> The absorbent pad according to any one of <5> to <9>, wherein the diffusion layer is composed of a fiber sheet, and the constituent fibers of the fiber sheet are entangled or joined together. <11> An absorbent article comprising the absorbent pad according to any one of <1> to <10>, and a diaper used by overlapping the absorbent pad on the skin-facing side.

[0074] According to the present invention, an absorbent pad is available that can quickly absorb stool even when stool containing high viscosity or a large amount of solid components is expelled.

Claims

1. An absorbent pad comprising: a surface layer having a convex portion that protrudes toward the skin and a recess with an opening at its bottom; a gap-forming layer made of a liquid-permeable material, having a convex portion that protrudes toward the skin and has an internal space, and forming a stool diffusion space between itself and the surface layer, which diffuses the stool supplied through the opening in a direction intersecting the thickness direction of the absorbent pad; and an inclusion layer made of a fiber aggregate, having a portion that penetrates the internal space, which draws in low-viscosity components from the stool in the stool diffusion space.

2. The absorbent pad according to claim 1, wherein the protrusion of the gap-forming layer has an opening at its apex.

3. In the region where the surface layer and the gap-forming layer overlap, the total area of ​​the openings in the surface layer is equal to or greater than the total area of ​​the openings in the gap-forming layer, as described in claim 2.

4. The absorbent pad according to claim 3, wherein the area of ​​each of the openings in the surface layer and the area of ​​each of the openings in the gap-forming layer are substantially the same.

5. The absorbent pad according to claim 1 or 2, further comprising: a diffusion layer that diffuses the low-viscosity component incorporated into the intake layer in a direction intersecting the thickness direction of the absorbent pad; and an absorbent layer that absorbs the low-viscosity component diffused by the diffusion layer.

6. The absorbent pad according to claim 5, wherein, when the surface layer is viewed from above, the convex portions and concave portions of the surface layer are arranged alternately and continuously along two different directions that intersect each other.

7. The absorbent pad according to claim 5, wherein the member constituting the diffusion layer has a higher hydrophilicity than the fiber aggregate constituting the inclusion layer.

8. The absorbent pad according to claim 5, wherein the diffusion layer is composed of a fiber sheet, and the inter-fiber distance of the fiber sheet is smaller than that of the fiber aggregate constituting the inclusion layer.

9. The absorbent pad according to claim 5, wherein the absorbent layer comprises a superabsorbent polymer.

10. The absorbent pad according to claim 5, wherein the diffusion layer is composed of a fiber sheet, and the constituent fibers of the fiber sheet are entangled or bonded together.

11. An absorbent article comprising an absorbent pad according to claim 5 and a diaper used with the absorbent pad placed on the skin-facing side.

Images