Absorbent article, and method for manufacturing a core wrap sheet

Abstract

The present invention provides an absorbent article, and a manufacturing method of a core wrap sheet, which is capable of maintaining liquid absorbency at a higher level even in the case of repeatedly absorbing body fluid such as urine. An absorbent body (7A) has a skin-facing surface (15) and a non-skin-facing surface (17), and includes an absorbent core (9A) and a core wrap sheet (11A) disposed on at least one side of the skin-facing surface (15) and the non-skin-facing surface (17). The core wrap sheet (11A) has an inner layer (16A) and an outer layer (18A). The inner layer (16A) contains 50% by mass or more of cellulose fibers, and has a core-facing surface (21) in contact with the absorbent core (9A), a non-core-facing surface (23), and a plurality of openings (27). The outer layer (18A) contains 50% by mass or more of thermoplastic synthetic fibers, and has a first surface (29) in contact with the non-core-facing surface (23), a second surface (31), a plurality of first grooves (33) recessed in a thickness direction from the first surface (29), and a plurality of second grooves (35) recessed in a thickness direction from the second surface (31).

Description

Technical Field

[0001] This invention relates to absorbent articles and methods for manufacturing core-coated sheets. Background Technology

[0002] Previously, absorbent products such as disposable diapers and sanitary napkins used absorbent cores covered with core-coating sheets, which were composed of hydrophilic fibers such as wood pulp fibers and highly absorbent polymer particles dispersed in the hydrophilic fibers.

[0003] Patent Document 1 discloses an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet. The absorbent body includes an absorbent core and a core-covering sheet covering its lower surface. The core-covering sheet comprises 50% by mass or more thermoplastic synthetic fibers and has a plurality of grooves and ridges alternately provided on its surface. The plurality of grooves and ridges extend along the long side direction of the absorbent core and are alternately provided at predetermined intervals along the short side direction of the absorbent core.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-525 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the case of Patent Document 1, by ensuring recoverable liquid delivery channels between the absorbent core and the core-covering sheet, and between the core-covering sheet and the liquid-impermeable backing sheet, the strength is not easily reduced even when a large amount of bodily fluid is absorbed, thus maintaining high absorbency. Since the maintenance of such absorbency is related to the improvement of the wearing comfort of absorbent articles, absorbent articles with further improved liquid absorbency are expected.

[0009] The purpose of this invention is to provide an absorbent article and a method for manufacturing a core-coated sheet that can maintain a higher level of liquid absorbency even when repeatedly absorbing bodily fluids such as urine.

[0010] Solution for solving the problem

[0011] The absorbent article of the present invention comprises: a liquid-permeable top sheet; a liquid-impermeable back sheet; and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body comprises: an absorbent core having a skin-facing side and a non-skin-facing side opposite to the skin-facing side, and having a long side direction, a short side direction, and a thickness direction; and a core-covering sheet disposed on at least one of the skin-facing side and the non-skin-facing side, the core-covering sheet having an inner layer and an outer layer, the inner layer comprising more than 50% by weight of cellulose fibers. The outer layer comprises more than 50% by mass of thermoplastic synthetic fibers and has a first surface in contact with the absorbent core, a second surface opposite to the first surface, a plurality of first grooves recessed in the first surface in the thickness direction, and a plurality of second grooves recessed in the second surface in the thickness direction. Each of the plurality of first grooves and each of the plurality of second grooves are alternately arranged at a predetermined interval.

[0012] The effects of the invention

[0013] The absorbent article of the present invention can maintain a higher level of liquid absorbency even when repeatedly absorbing bodily fluids such as urine. Attached Figure Description

[0014] Figure 1 This is a top view of the absorbent article according to the first embodiment.

[0015] Figure 2 It is along the first embodiment Figure 1 A cross-sectional view of the absorber along line II-II.

[0016] Figure 3 This is a partially enlarged cross-sectional view of the absorber in the first embodiment.

[0017] Figure 4 This is a partial cross-sectional perspective view of the core-coated sheet according to the first embodiment.

[0018] Figure 5 This is a schematic diagram illustrating an example of a manufacturing apparatus for producing the core-coated sheet according to the first embodiment.

[0019] Figure 6 This is a schematic diagram showing a shaping roller that can be used in a manufacturing apparatus for manufacturing the core-coated sheet of the first embodiment.

[0020] Figure 7A It is a variation (1) of the first embodiment along Figure 1 A cross-sectional view of the absorber along line II-II.

[0021] Figure 7B It is a variation (2) of the first embodiment along Figure 1 A cross-sectional view of the absorber along line II-II.

[0022] Figure 8 This is a partially enlarged cross-sectional view of the absorber in a modified example (3) of the first embodiment.

[0023] Figure 9 This is a partial cross-sectional perspective view of the core-coated sheet according to the second embodiment.

[0024] Figure 10 This is a top view of the core-coated sheet according to the second embodiment.

[0025] Figure 11 This is a schematic diagram showing a shaping roller that can be used in a manufacturing apparatus for manufacturing the core-coated sheet of the second embodiment.

[0026] Figure 12 This is a top view of the absorbent core of the absorbent article according to the third embodiment.

[0027] Figure 13 It is along the third embodiment Figure 12 A cross-sectional view of the absorption core of the XIII-XIII line.

[0028] Figure 14 It is a variation of the third embodiment along Figure 12 A cross-sectional view of the absorption core of the XIII-XIII line. Detailed Implementation

[0029] The embodiments of the present invention relate to the following methods.

[0030] [Method 1]

[0031] An absorbent article comprising: a liquid-permeable top sheet; a liquid-impermeable back sheet; and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body comprises: an absorbent core having a skin-facing side and a non-skin-facing side opposite to the skin-facing side, and having a long side direction, a short side direction, and a thickness direction; and a core-covering sheet disposed on at least one of the skin-facing side and the non-skin-facing side, the core-covering sheet having an inner layer and an outer layer, the inner layer comprising more than 50% by weight of fibers. The outer layer comprises 50% by mass or more thermoplastic synthetic fibers and has a core-facing surface in contact with the absorbent core, a non-core-facing surface opposite to the core-facing surface, and a plurality of openings extending from the core-facing surface to the non-core-facing surface. It also has a first surface in contact with the non-core-facing surface, a second surface opposite to the first surface, a plurality of first grooves recessed in the thickness direction on the first surface, and a plurality of second grooves recessed in the thickness direction on the second surface. Each of the plurality of first grooves and each of the plurality of second grooves are alternately arranged at predetermined intervals.

[0032] Body fluids excreted onto the top sheet surface permeate through the top sheet. When the core-covered sheet covers the skin-facing side, the body fluids permeate through the outer layer to the space between the outer and inner layers, and through multiple openings in the inner layer to the space between the inner layer and the absorbent core. Conversely, when the core-covered sheet covers the non-skin-facing side, a portion of the body fluids permeating through the top sheet is absorbed by the absorbent core, while the unabsorbed fluids reach the space between the absorbent core and the inner layer, and through multiple openings in the inner layer to the space between the inner and outer layers. The space between the absorbent core and the inner layer is referred to as the first diffusion space, and the space between the inner and outer layers is referred to as the second diffusion space. In either case, due to the diffusivity of the inner layer, which contains 50% or more cellulose fibers, the body fluids diffuse within the inner layer via capillary action, and diffuse in both the first and second diffusion spaces. Furthermore, the body fluids diffuse through a third diffusion space having a second groove. Therefore, in addition to diffusion in the first, second, and third diffusion spaces, this absorbent article can also utilize the capillary effect generated inside the inner layer to diffuse body fluid more efficiently, thus maintaining a higher level of liquid absorbency. The outer layer, containing more than 50% by mass of thermoplastic synthetic fibers, does not easily lose strength even with repeated absorption of body fluid, thus suppressing deformation of the multiple first and second channels. Therefore, this absorbent article can diffuse a large amount of body fluid through the multiple first and second channels even with repeated absorption of body fluid.

[0033] [Method 2]

[0034] In the absorbent article of method 1, the non-core facing surface and the first surface are not joined together.

[0035] Because this absorbent article more reliably forms a second diffusion space, bodily fluids can diffuse more reliably within this space. Therefore, this absorbent article can maintain liquid absorbency at a higher level. When the non-core facing surface and the first surface are bonded together with an adhesive, or when the non-core facing surface and the first surface are bonded together by the interlacing of fibers in the inner and outer layers, the diffusion of bodily fluids is hindered because the second diffusion space is blocked. When the non-core facing surface and the first surface are bonded together by an embossing process, bodily fluids remain in the portion where the fiber density increases due to the embossing process, hindering the diffusion of bodily fluids.

[0036] [Method 3]

[0037] In the absorbent article described in method 1 or 2, each of the plurality of first grooves and each of the plurality of second grooves extends in a direction parallel to the long side direction and is alternately arranged in a direction parallel to the short side direction at predetermined intervals.

[0038] Because bodily fluids can easily diffuse along the long side through multiple first grooves and multiple second grooves, this absorbent article allows for more efficient and flexible use of the absorbent core.

[0039] [Method 4]

[0040] In any one of the absorbent articles of methods 1 to 3, the inner layer has a plurality of inner layer grooves recessed along the thickness direction on the core-facing surface.

[0041] Body fluid diffuses through multiple inner layer grooves between the core-facing surfaces of the absorbent core and the inner layer, thus enabling the absorbent article to diffuse body fluid more efficiently.

[0042] [Method 5]

[0043] In the absorbent article of method 4, each of the plurality of inner layer grooves overlaps with each of the plurality of first grooves, respectively.

[0044] Even under repeated absorption of bodily fluids, deformation of the multiple first grooves and multiple inner grooves can be suppressed. Therefore, this absorbent article can maintain liquid absorbency at a higher level because it can diffuse a large amount of bodily fluid through each of the multiple first grooves that overlap with each of the multiple inner grooves.

[0045] [Method 6]

[0046] In any one of the absorbent articles of methods 1 to 5, the inner layer is a paper towel and the outer layer is a spunbond nonwoven fabric.

[0047] Because the inner layer is made of tissue paper, bodily fluids can diffuse more easily within it. Since the outer layer is spunbond nonwoven fabric, the second and third diffusion spaces can be formed more reliably. Therefore, this absorbent article can maintain liquid absorbency at a higher level. With each inner layer groove overlapping each of the plurality of first grooves, tissue paper with excellent hydrophilicity can be used for the core-covered sheet by utilizing the low support strength of the spunbond nonwoven fabric. Because the elongation of the tissue paper is lower than that of the spunbond nonwoven fabric, when forming the plurality of first and second grooves while the inner and outer layers are overlapped, the tissue paper cannot follow the deformation of the spunbond nonwoven fabric, resulting in partial cracking on the tissue paper and thus forming multiple openings. Therefore, by forming multiple first and second grooves on the outer layer while simultaneously forming multiple openings in the inner layer, the core-covered sheet can be formed efficiently.

[0048] [Method 7]

[0049] In the absorbent article of method 6, the inner layer and the absorbent core are joined by a hot melt adhesive.

[0050] Because the inner layer is made of tissue paper, it has a high fiber density, resulting in a larger contact area between the inner layer and the hot-melt adhesive, thus providing strong adhesion to the absorbent core. The outer layer does not easily lose strength even after repeated absorption of bodily fluids, thus preventing deformation of the multiple first and second grooves. Therefore, this absorbent article can prevent deformation even after repeated absorption of bodily fluids.

[0051] [Method 8]

[0052] In any one of the absorbent articles of methods 1 to 7, the outer layer and the absorbent core are joined through the plurality of openings.

[0053] Because the outer layer and the absorbent core are directly bonded, misalignment between the outer layer and the absorbent core can be prevented even if the inner layer deforms after absorbing bodily fluids. Therefore, this absorbent article can more reliably suppress distortion even when repeatedly absorbing bodily fluids.

[0054] [Method 9]

[0055] In any one of the absorbent articles of methods 1 to 8, the absorbent core has a low unit area weight portion where the absorbent material has a smaller unit area weight than the surrounding material, and the inner layer is colored in a different color than the absorbent core.

[0056] For absorbents that have not absorbed bodily fluids, the location of the low-weight area can be identified by the color of the inner layer through which the low-weight area is visible. Therefore, when dry, the user can use the low-weight area as a marker for alignment. However, after absorbing bodily fluids, the absorbent becomes wet, making it difficult to visually identify the color of the inner layer through which the low-weight area is visible. Therefore, when wet, the user can visually confirm the state of fluid absorption.

[0057] [Method 10]

[0058] In any one of the absorbent articles of methods 1 to 9, the core-coated sheet is disposed on the non-skin-facing side.

[0059] Bodily fluids excreted onto the top sheet permeate through the top sheet, with a portion being absorbed by the absorbent core. The unabsorbed fluids reach the first diffusion space from the non-skin-facing side of the absorbent core and then through multiple openings in the inner layer to the second diffusion space. Due to the diffusivity of the inner layer, which contains at least 50% cellulose fibers, the fluids diffuse within the inner layer, the first diffusion space, and the second diffusion space. Furthermore, the fluids permeate through the outer layer to the second surface, and then diffuse through the third diffusion space. Therefore, this absorbent article can diffuse bodily fluids more efficiently through the inner layer, the first diffusion space, the second diffusion space, and the third diffusion space.

[0060] [Method 11]

[0061] In the absorbent article of method 10, the inner layer has a plurality of inner layer grooves recessed along the thickness direction on the core-facing surface, and each of the plurality of inner layer grooves is respectively formed with each of the plurality of openings.

[0062] The bodily fluid diffuses within the inner layer groove while simultaneously permeating through multiple openings between the non-core facing surface and the first surface, thus diffusing between them. Therefore, this absorbent article can diffuse bodily fluids more efficiently.

[0063] [Method 12]

[0064] In any one of the methods 1 to 11, the absorbent core includes: a skin-facing side layer containing the skin-facing surface and a non-skin-facing side layer containing the non-skin-facing surface, the skin-facing side layer or the non-skin-facing side layer comprising: a plurality of grooves, the plurality of grooves including a plurality of main grooves extending along the thickness direction; and a plurality of bases, each of the plurality of grooves and each of the plurality of bases being alternately arranged.

[0065] Excreted bodily fluids are transported through multiple channels to a location on the absorbent core furthest from the excretion site, allowing for absorption over a larger area and thus further enhancing the overall absorbency of the absorbent core. Because the liquid is transported from the excretion site, the reduction in absorbency of the absorbent core near the excretion site is prevented.

[0066] [Method 13]

[0067] An absorbent article comprising: a liquid-permeable top sheet; a liquid-impermeable back sheet; and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body comprises: an absorbent core having a skin-facing side and a non-skin-facing side opposite to the skin-facing side, and having a long side direction, a short side direction, and a thickness direction; and a core-covering sheet disposed on at least one of the skin-facing side and the non-skin-facing side, the absorbent core comprising: a skin-side layer including the skin-facing side and a non-skin-side layer including the non-skin-facing side, the skin-side layer or the non-skin-side layer having a plurality of grooves and a plurality of bases, the plurality of grooves including along the... The core-covering sheet comprises a plurality of main grooves extending through the thickness direction, each of the plurality of grooves and each of the plurality of bases being alternately arranged. The core-covering sheet has an inner layer and an outer layer. The inner layer contains more than 50% by mass of cellulose fibers and has a core-facing surface in contact with the absorbent core and a non-core-facing surface opposite to the core-facing surface. The outer layer contains more than 50% by mass of thermoplastic synthetic fibers and has a first surface in contact with the non-core-facing surface, a second surface opposite to the first surface, a plurality of first grooves recessed in the thickness direction on the first surface, and a plurality of second grooves recessed in the thickness direction on the second surface. Each of the plurality of first grooves and each of the plurality of second grooves are alternately arranged at a predetermined interval.

[0068] This absorbent material, like Method 1, has a first diffusion space, a second diffusion space, and a third diffusion space, and therefore can achieve the same effect as Method 1.

[0069] [Method 14]

[0070] A method for manufacturing a core-coated sheet is a method for manufacturing an absorbent body comprising an absorbent core and an absorbent core-coated sheet, wherein the core-coated sheet comprises: an outer layer comprising 50% by mass or more thermoplastic synthetic fibers and having a first side and a second side opposite to the first side; and an inner layer comprising 50% by mass or more cellulose fibers and having a core-facing side and a non-core-facing side opposite to the core-facing side, the method for manufacturing the core-coated sheet comprising: forming an absorbent body with an absorbent core and an absorbent core-coated sheet; wherein the outer layer comprises a core-facing side and a ... The steps include: preheating the outer continuous body; and conveying the preheated outer continuous body and the inner continuous body composed of the inner layer to a pair of shaping members having a first shaping member and a second shaping member, with the first surface and the non-core facing surface in contact, to form a plurality of core facing grooves recessed in the thickness direction on the core facing surface, a plurality of non-core facing grooves recessed in the thickness direction on the second surface, and a plurality of openings penetrating from the core facing surface to the non-core facing surface in the inner continuous body.

[0071] By forming multiple core-facing grooves, multiple non-core-facing grooves, and multiple openings in a state of overlapping outer and inner continuous layers, a core-coated sheet with an integrated inner and outer layer can be easily manufactured. When the resulting core-coated sheet covers at least one of the skin-facing and non-skin-facing surfaces of the absorbent core, bodily fluids diffuse more efficiently in the space between the absorbent core and the inner layer (i.e., the first diffusion space), the space between the inner and outer layers (i.e., the second diffusion space), the third diffusion space with the second groove, and within the inner layer itself.

[0072] The absorbent article according to the embodiments will be described below.

[0073] In this instruction manual, unless otherwise specified, "viewing an object from above or below its thickness direction when it is placed on a horizontal surface in an unfolded state" is referred to as "top view." When the object is an absorbent article, the view from the surface side along the thickness direction when the absorbent article is unfolded is sometimes simply referred to as "top view." When the object is an absorbent core, the view from the non-skin-facing side of the absorbent core along the thickness direction when the absorbent article is unfolded is sometimes simply referred to as "top view."

[0074] Unless otherwise specified, the various directions used in this specification are as follows: "Long side direction" refers to the direction along which the object's length is longer when viewed from above; "short side direction" refers to the direction along which the object's length is shorter when viewed from above; and "thickness direction" refers to the direction perpendicular to an object placed unfolded on a horizontal surface. These long side, short side, and thickness directions are all orthogonal to each other. It should be noted that directions include two opposite directions, but in the cases shown in the accompanying drawings, sometimes only one direction orthogonal to the paper is shown.

[0075] 1. First Implementation Method

[0076] The absorbent article of the first embodiment will be described with reference to the accompanying drawings. Figure 1 As shown, the absorbent article 1 is an example of a disposable diaper, comprising a liquid-permeable top sheet 3, a liquid-impermeable back sheet 5, and an absorbent body 7A disposed between the top sheet 3 and the back sheet 5. The absorbent article 1 is divided along its long side L into three regions: a front waist region FW, a back waist region RW, and a crotch region C between the front waist region FW and the back waist region RW. The absorbent article 1 also includes: a pair of leak-proof walls 101 including elastic members 103, a fixing part 105 for fixing the leak-proof walls 101 to the top sheet 3, elastic members 107 around the legs, and fasteners 109, etc. It should be noted that these are well known in the art, therefore, descriptions are omitted.

[0077] The absorbent 7A absorbs and retains bodily fluids excreted into the top sheet 3. The absorbent 7A has a long side direction L, a short side direction W, and a thickness direction T. The absorbent 7A is disposed across these three regions. At both ends of the absorbent 7A in the long side direction L, there are first end portions 2 and second end portions 6 with the same length in the short side direction W. At the central portion in the long side direction L, there is a constricted portion 4 with a length in the short side direction W shorter than that of the first end portions 2 and the second end portions 6. The first end portion 2 and the constricted portion 4, and the second end portion 6 and the constricted portion 4, are connected via inclined edges that slope inward toward the constricted portion 4 in the short side direction W.

[0078] like Figure 2As shown, the absorbent body 7A includes an absorbent core 9A and a core-covering sheet 11A. It should be noted that in this embodiment, since the long side direction, short side direction, and thickness direction of the absorbent article 1 are the same as these directions of the absorbent body 7A, the long side direction L, short side direction W, and thickness direction T are also used as these directions of the absorbent article 1. The absorbent core 9A contains absorbent fibers and superabsorbent polymer particles (SAP). The absorbent fibers can be pulp fibers. There are no particular limitations on the pulp fibers as long as they can be used in hygiene products; for example, cellulose fibers can be cited. Examples of cellulose fibers include wood pulp (e.g., softwood pulp, hardwood pulp), cross-linked pulp, and non-wood pulp. There are no particular limitations on the superabsorbent polymer particles as long as they can be used in hygiene products; for example, polyacrylate-based, polysulfonate-based, and maleic anhydride-based superabsorbent polymer particles can be cited. The average area weight of the absorbent fibers in the absorbent core 9A is preferably 50 to 450 g / m². 2 More preferably 80–350 g / m 2 The average weight per unit area of ​​the highly absorbent polymer particles in the absorbent core 9A is preferably 100–500 g / m². 2 More preferably, it is 150–400 g / m 2 The average weight per unit area of ​​the absorbent core was determined according to the following method. Samples were cut into 5cm × 5cm pieces, dried in an atmosphere above 100°C, and their mass was measured. The measured mass was then divided by the area of ​​the sample to calculate the weight per unit area. The average weight per unit area of ​​the 10 samples was taken as the average weight per unit area of ​​the absorbent core. The method for determining the average weight per unit area of ​​the highly absorbent polymer particles was as follows. Five samples of a specified length and width (e.g., 4mm × 4mm) were cut from the absorbent core. The highly absorbent polymer particles contained in each sample were sorted, and the total mass of the highly absorbent polymer particles contained in each sample was measured. The average weight per unit area was obtained by averaging the values ​​obtained by dividing this measured value by the sample area. Furthermore, the average density was obtained by dividing the average weight per unit area by the sample thickness described below.

[0079] The absorber core 9A has a skin-facing surface 15 and a non-skin-facing surface 17 opposite to the skin-facing surface 15, and has a long side direction L, a short side direction W, and a thickness direction T. The absorber core 9A has a shape that is substantially the same as that of the absorber body 7A. The thickness of the absorber core 9A is preferably 0.2 to 10 mm, more preferably 1.0 to 8.0 mm, and even more preferably 2.0 to 6.0 mm. It should be noted that, unless otherwise specified in this specification, the thickness (mm) of the object (e.g., absorber body, absorber core) refers to the thickness of the object as measured by the FS-60DS [measuring surface 44 mm (diameter), measuring pressure 3 g / cm] manufactured by Daiei Scientific Instruments Co., Ltd. 2 Under standard conditions (temperature 23±2℃, relative humidity 50±5%), pressure was applied to five different parts of the absorber, and the thickness at each part was measured after 10 seconds of pressure application, resulting in the average of the five measured values.

[0080] The core-covered sheet 11A encapsulates the absorbent core 9A. The core-covered sheet 11A can also be bonded to the absorbent core 9A via multiple linear or dot-shaped adhesive portions (not shown). These adhesive portions can be formed, for example, by a hot-melt adhesive. The core-covered sheet 11A has an upper core-covered sheet 12A and a lower core-covered sheet 14A. The upper core-covered sheet 12A covers the skin-facing surface 15 of the absorbent core 9A. The upper core-covered sheet 12A has the same or a smaller shape than the skin-facing surface 15 and is formed of the same hydrophilic nonwoven fabric as the outer layer described later. The lower core-covered sheet 14A covers the non-skin-facing surface 17 and sides of the absorbent core 9A. The lower core cover 14A covers the side from the non-skin-facing surface 17, and in a state where the end of the short side direction W of the lower core cover 14A overlaps with the end of the short side direction W of the upper core cover 12A, it is joined to the upper core cover 12A on the skin-facing surface 15.

[0081] like Figure 3 As shown, the lower core-covering sheet 14A has an inner layer 16A and an outer layer 18A. The inner layer 16A is in contact with the absorbent core 9A. The inner layer 16A is bonded to the absorbent core 9A by the aforementioned hot-melt adhesive. The inner layer 16A comprises a nonwoven fabric as an aggregate layer of fibers containing more than 50% by mass of cellulose fibers. Examples of cellulose fibers include, but are not limited to, wood pulp (e.g., softwood pulp, hardwood pulp), cross-linked pulp, and non-wood pulp. In addition to cellulose fibers, the inner layer 16A may also contain thermoplastic synthetic fibers and paper strength enhancers. The thickness of the inner layer 16A is preferably 0.1 to 0.5 mm. The inner layer 16A may also be a tissue. A tissue refers to a tissue with a wet strength of 10 g / m². 2 ~20g / m 2The inner layer 16A has a core-facing surface 21 facing the absorbent core 9A and a non-core-facing surface 23 opposite to the core-facing surface 21. The inner layer 16A has the same shape as the absorbent core 9A, a shape smaller than the absorbent core, or the same shape as the outer layer 18A. The inner layer 16A may also have a plurality of inner layer grooves 25 recessed along the thickness direction T on the core-facing surface 21. The plurality of inner layer grooves 25 extend along the long side direction L and are arranged at predetermined intervals along the short side direction W.

[0082] like Figure 4 As shown, the inner layer 16A has an opening 27 extending along the thickness direction of the inner layer 16A. The opening 27 extends between the core-facing surface 21 and the non-core-facing surface 23, from the core-facing surface 21 to the non-core-facing surface 23. Unlike the pores formed between fibers, the opening 27 is intentionally formed in the inner layer 16A and has a much larger area than the pores formed between fibers. Multiple openings 27 are connected along the long side direction L and arranged in multiple rows between the bottom and top of the inner layer groove 25. Multiple openings 27 may also be formed mainly in the middle part between the bottom and top of the inner layer groove 25. Figure 4 The arrangement and shape of the openings 27 shown are the same, but in practice, the arrangement and shape of the openings 27 do not necessarily have to be the same. The shape of the openings 27 is approximately circular, elliptical in the long side direction L, or rhomboid. The openings 27 do not need to be linearly symmetrical. The openings 27 may not be completely open spaces. The openings 27 may also be a mixture of fibers embedded in their internal space and some protruding fibers. The length of the long side direction L of the openings 27 is 0.1 to 5 mm, preferably 0.2 to 2 mm, and the length of the short side direction W is 0.05 to 3 mm, preferably 0.1 to 1 mm. The core-facing surface 21 of the inner layer 16A contacts the non-skin-facing surface 17 at the top between the inner layer grooves 25. The porosity of the internal space of the openings 27 is preferably 1 to 50%, more preferably 1.5 to 35%, and even more preferably 2.5 to 20%.

[0083] The outer layer 18A is positioned on the opposite side of the inner layer 16A from the absorber core 9A. Figure 3The outer layer 18A has a non-skin-facing surface 17 covering the absorbent core 9A and its side profile. The outer layer 18A may also not be bonded to the inner layer 16A. The outer layer 18A is formed of a hydrophilic nonwoven fabric. The outer layer 18A may, for example, include any one or more of spunbond nonwoven fabric, meltblown nonwoven fabric, hot-air nonwoven fabric, and air-laid nonwoven fabric. The outer layer 18A contains 50% by mass or more of thermoplastic synthetic fibers. Examples of thermoplastic synthetic fibers include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and ionomer resins; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, and polylactic acid; and polyamides such as nylon. Examples of other constituent fibers include wood or non-wood pulp fibers, natural fibers (e.g., wool, cotton), regenerated cellulose fibers (e.g., rayon, acetate fiber), and inorganic fibers (e.g., glass fiber, carbon fiber). The fibers constituting the outer layer 18A can be composite fibers such as core-sheath type fibers, parallel type fibers, and island type fibers; hollow fibers; profiled fibers such as flat, Y-shaped, and C-shaped fibers; three-dimensionally crimped fibers with potential or obvious crimp; or split fibers that have been divided by physical loads such as water flow, heat, or embossing. The area weight per unit area of ​​the outer layer is typically 10–75 g / m². 2 Preferably, it is 10–45 g / m 2 More preferably, it is 10–25 g / m 2 The thickness of the outer layer is typically 0.1–5 mm, preferably 0.2–3 mm, and more preferably 0.4–2 mm. The outer layer 18A can also be a 3-layer SMS nonwoven fabric consisting of spunbond nonwoven fabric sandwiching meltblown nonwoven fabric, or a 4-layer SMMS nonwoven fabric consisting of spunbond nonwoven fabric sandwiching two pieces of meltblown nonwoven fabric.

[0084] like Figure 4As shown, the outer layer 18A has: a first surface 29 facing the non-core facing surface 23, a second surface 31 on the opposite side of the first surface 29, a plurality of first grooves 33 recessed in the thickness direction T on the first surface 29, and a plurality of second grooves (also referred to as non-core facing grooves) 35 recessed in the thickness direction T on the second surface 31. Each of the plurality of first grooves 33 and each of the plurality of second grooves 35 are arranged alternately at predetermined intervals. Each of the plurality of first grooves 33 and each of the plurality of second grooves 35 extends in a direction parallel to the long side direction L and is arranged alternately in a direction parallel to the short side direction W at predetermined intervals. The second grooves 35 form a first ridge 37 that protrudes in the thickness direction T when viewed from the first surface 29. The first ridges 37 are disposed between the first grooves 33 and contact the non-core facing surface 23. The first ridges 37 can also be joined to the non-skin facing surface 17 by means of the aforementioned adhesive portion through the opening 27. The first grooves 33 form a second ridge 39 that protrudes in the thickness direction T when viewed from the second surface 31. The second ridge 39 is disposed between the second grooves 35 and contacts the back sheet 5 (not shown in this figure). Each of the plurality of first grooves 33 may also overlap with each of the plurality of inner layer grooves 25 respectively. The overlapping first grooves 33 and inner layer grooves 25 are referred to as core-facing grooves 24. Figure 3 The non-core facing surface 23 and the aforementioned first surface 29 are not joined together.

[0085] The height from the bottom of the first groove 33 of the outer layer 18A to the top of the first ridge 37 (hereinafter referred to as "upper surface side ridge height") is preferably 0.1 to 5 mm, more preferably 0.2 to 3 mm, and even more preferably 0.25 to 2 mm. It should be noted that the top of the first ridge 37 is located approximately at the center of the first ridge 37 in the short side direction W. On the first surface 29 side, the interval between the tops of adjacent first ridges 37 (hereinafter referred to as "upper surface side ridge interval") is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and even more preferably 0.75 to 2 mm. With respect to these ranges of upper surface side ridge height and upper surface side ridge interval, a space is formed between the inner layer 16A and the outer layer 18A, and between the outer layer 18A and the back sheet 5, which functions as a liquid transport channel, allowing bodily fluids to be introduced into and diffused within this space. From the viewpoint of improving liquid diffusivity, it is preferable that the aforementioned plurality of first ridges 37 and first grooves 33 extend continuously from one end edge of the outer layer 18A to the other end edge in a direction parallel to the long side direction L of the absorber core 9A. The height of the aforementioned upper surface side ridges and the spacing between the upper surface side ridges are measured using a two-dimensional laser displacement meter. As a two-dimensional laser displacement meter, for example, the high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation can be cited.

[0086] The manufacturing method of the core-coated sheet 11A is described below. Figure 5This is a schematic diagram illustrating an example of a manufacturing apparatus for producing the core-coated sheet according to the first embodiment. Figure 6 This is a schematic diagram showing a shaping roller that can be used in a manufacturing apparatus for manufacturing the core-coated sheet of the first embodiment. Figure 5 The manufacturing apparatus 41 shown includes a first winding device 43, a preheating device 45, a second winding device 47, a shaping device 49A, and a winding device 52. The first winding device 43 winds the outer continuous body 118, which is composed of the outer layer 18A, into a roller shape and winds the outer continuous body 118 out in the conveying direction. The preheating device 45 preheats the wound outer continuous body 118. In this embodiment, the preheating device 45 includes a pair of upper and lower heating rollers 44 and 46. The preheating device 45 winds the conveyed outer continuous body 118 onto the rotating lower heating roller 44 for heating. After the outer continuous body 118 is heated by the lower heating roller 44, the outer continuous body 118 is transferred to the rotating upper heating roller 46, and the outer continuous body 118 is heated again by the upper heating roller 46. The second winding device 47 winds the inner continuous body 116, which is composed of the inner layer 16A, into a roller shape and winds the inner continuous body 116 out in the conveying direction.

[0087] like Figure 6 As shown, the shaping device 49A includes a pair of upper and lower stretching rollers 48 and 50A. The upper stretching roller 50A has a plurality of protrusions 51 and a plurality of grooves 53 disposed between each of the protrusions 51. The plurality of protrusions 51 and the plurality of grooves 53 extend circumferentially and are arranged alternately at certain intervals in the roller width direction. On the other hand, the lower stretching roller 48 has a plurality of grooves 57 disposed on its outer peripheral surface in a manner that engages with the protrusions 51 of the upper stretching roller 50A and a plurality of protrusions 55 disposed in a manner that engages with the grooves 53 of the upper stretching roller 50A.

[0088] When manufacturing the core-coated sheet 11A using the manufacturing apparatus 41, a preheating process is performed sequentially, which involves preheating the outer continuous layer 118 wound from the first winding device 43, and a shaping process is performed in which the preheated outer continuous layer 118 and the inner continuous layer 116 wound from the second winding device 47 are overlapped, and then shaped. The preheating process is performed by bringing the outer continuous layer 118 into contact with the outer peripheral surfaces of the upper and lower pair of heating rollers 44, 46 in sequence. The preheating temperature is a temperature lower than the melting point of the thermoplastic synthetic fiber contained in the outer continuous layer 118. For example, when the thermoplastic synthetic fiber contained in the outer continuous layer 118 is a core-sheath type composite fiber of polyethylene terephthalate (PET) and high-density polyethylene (HDPE), the preheating temperature is preferably about 60 to 120°C.

[0089] In the shaping process, the inner continuous layer 116 and the outer continuous layer 118, which has been conveyed from the preheating process, are fed in the shaping device 49A between a pair of meshing and rotating stretching rollers 48 and 50A, with the non-core facing surface 23 in contact with the first surface 29. The pair of stretching rollers 48 and 50A stretch the inner continuous layer 116 and the outer continuous layer 118 between the protrusions 51 and grooves 53 of the meshing upper stretching roller 50A and the grooves 57 and protrusions 55 of the lower stretching roller 48. At this time, the upper stretching roller 50A forms a core facing groove 24 by pressing the part of the protrusion 51 that contacts the inner continuous layer 116 into the groove 57 of the lower stretching roller 48. The lower stretching roller 48 forms a non-core facing groove (second groove) 35 by pressing the part of the protrusion 55 that contacts the outer continuous layer 118 into the groove 53 of the upper stretching roller 50A. It should be noted that, in the shaping process, to facilitate shaping, the stretching rollers 48 and 50A can be heated to 60–120°C while shaping. The core-coated sheet continuous body 111 after the shaping process is wound using the winding device 52, and the core-coated sheet continuous body 111 is used as the core-coated sheet 11A for absorbent article 1, thus enabling the manufacture of absorbent article 1 according to known methods.

[0090] During the shaping process, the protrusion 51 of the upper stretching roller 50A is pressed into the groove 57 of the lower stretching roller 48, while the protrusion 55 of the lower stretching roller 48 is pressed into the groove 53 of the upper stretching roller 50A. The outer continuous body 118 is stretched in the portion between the protrusions 51 and 55 (hereinafter referred to as the "engaging portion"), and deformed along the protrusions 51 and 55, thereby forming the first groove 33 and the second groove 35.

[0091] When the inner continuous layer 116 is formed from tissue paper and the outer continuous layer 118 is formed from spunbond nonwoven fabric, the elongation of the tissue paper is smaller than that of the spunbond nonwoven fabric. Therefore, since the inner continuous layer 116 does not elongate as much as the outer continuous layer 118, it is partially torn at the aforementioned interlocking portion. As a result, the inner continuous layer 116 cannot follow the deformation of the outer continuous layer 118, causing the cellulose fibers to break, thereby partially creating cracks on the surface and forming multiple openings 27 penetrating the inner continuous layer 116. Therefore, since multiple openings 27 can be formed simultaneously with multiple core-facing grooves 24, the core-coated sheet 11A can be manufactured more efficiently.

[0092] The function and effect of the absorbent article 1 described above will be explained. First, bodily fluids excreted onto the surface of the top sheet 3 permeate through the top sheet 3. The bodily fluids permeating through the top sheet 3 pass through the upper core covering sheet 12A from the skin-facing surface 15 into the interior of the absorbent core 9A, and a portion is absorbed by the absorbent core 9A. The bodily fluids not absorbed by the absorbent core 9A seep out from the non-skin-facing surface 17, reaching the first diffusion space between the non-skin-facing surface 17 and the core-facing surface 21, and reaching the second diffusion space between the non-core-facing surface 23 and the first surface 29 through the multiple openings 27 of the inner layer 16A. Since the inner layer 16A has excellent diffusivity due to containing more than 50% by mass of cellulose fibers, the bodily fluids diffuse inside the inner layer 16A, in the first diffusion space, and in the second diffusion space. Furthermore, the bodily fluids reaching the first surface 29 diffuse through the first groove 33 while passing through the interior of the outer layer 18A to reach the third diffusion space between the second surface 31 and the back sheet 5. The bodily fluid reaching the space between the second surface 31 and the back surface 5 diffuses through the third diffusion space. Therefore, in addition to diffusion through the first, second, and third diffusion spaces, the absorbent article 1 can also utilize the capillary effect generated inside the inner layer 16A to diffuse the bodily fluid more efficiently, thus maintaining a higher level of liquid absorbency. The outer layer 18A, containing more than 50% by mass of thermoplastic synthetic fibers, does not easily lose strength even with repeated absorption of bodily fluid, thus suppressing deformation of the multiple first grooves 33 and multiple second grooves 35. Therefore, even with repeated absorption of bodily fluid, the absorbent article 1 can diffuse a large amount of bodily fluid through the multiple first grooves 33 and multiple second grooves 35.

[0093] When the non-core facing surface 23 and the first surface 29 are not joined together, the second diffusion space can be more reliably secured. Therefore, bodily fluids can diffuse more reliably in the second diffusion space. With the inner layer groove 25, bodily fluids passing through the core facing surface 21 of the absorbent core 9A and the inner layer 16A can diffuse in the inner layer groove 25. With the core facing groove 24 having the inner layer groove 25 overlapping the first groove 33, the inner layer groove 25 of the core facing groove 24 is held by the first groove 33, thus suppressing deformation of the core facing groove 24 even during repeated absorption of bodily fluids. Therefore, the absorbent article 1 can diffuse a large amount of bodily fluids through the core facing groove 24. When the inner layer 16A is formed of tissue paper and the inner layer 16A and the absorbent core 9A are joined by a hot-melt adhesive, the tissue paper of the inner layer 16A has a high fiber density, and correspondingly, the contact area between the inner layer 16A and the hot-melt adhesive becomes larger, thus resulting in high adhesion to the absorbent core 9A. Therefore, the absorbent article 1 can suppress deformation even when repeatedly absorbing bodily fluids. The outer layer 18A, as described above, has multiple first ridges 37 (second grooves 35) and multiple first grooves 33, thereby improving the softness and elasticity of the outer layer 18A and enhancing the ability of the core covering sheet 11A to deform in accordance with the wearer's movements, thus improving the wearing comfort of the absorbent article 1. When the first ridges 37 are joined to the non-skin-facing surface 17 via the openings 27 using the aforementioned adhesive portion, misalignment between the outer layer 18A and the absorbent core 9A can be prevented even if the inner layer 16A, which has absorbed bodily fluids, deforms.

[0094] The absorbent article of the present invention is not limited to the embodiments described above, and can be appropriately combined and modified without departing from the purpose and spirit of the invention. For example, although the case where the inner groove 25, the first groove 33, and the second groove 35 extend along the long side direction L has been described, they can also be formed to extend along the short side direction W. In this case, Figure 5 In the shaping process shown, it can also replace Figure 6 The pair of stretching rollers 48 and 50A shown are a pair of stretching rollers (not shown) with multiple protrusions and multiple grooves facing different directions. For example, the multiple protrusions and multiple grooves of the upper stretching roller extend along the width direction of the roller and are alternately arranged at certain intervals in the circumferential direction of the roller. On the other hand, the lower stretching roller has multiple grooves and multiple protrusions on its outer peripheral surface that are provided to engage with the protrusions of the upper stretching roller. When the inner groove 25, the first groove 33 and the second groove 35 extend along the short side direction W, the opening can be an elongated elliptical or rhomboid shape in the short side direction W.

[0095] Figure 7A It is a variation (1) of the first embodiment along Figure 1A cross-sectional view of the absorber 7B along line II-II. The core-covering sheet 11B can also be joined to the non-skin-facing surface 17. The core-covering sheet 11B has an upper core-covering sheet 12B and a lower core-covering sheet 14B. The lower core-covering sheet 14B has the same or slightly smaller shape than the non-skin-facing surface 17, and has an inner layer 16A and an outer layer 18B. The upper core-covering sheet 12B covers the skin-facing surface 15 and the side surface. The upper core-covering sheet 12B is joined to the lower core-covering sheet 14B on the non-skin-facing surface 17 while covering the side surface from the skin-facing surface 15 and overlapping the end of the lower core-covering sheet 14B in the short side direction W.

[0096] Figure 7B It is a variation (2) of the first embodiment along Figure 1 A cross-sectional view of the absorber 7C along line II-II. The core-covered sheet 11C can also be a single sheet formed by integrating the upper and lower core-covered sheets. The core-covered sheet 11C, formed by the single sheet, has a non-skin-facing region 59 covering the non-skin-facing surface 17, a pair of side regions 61 covering the side surfaces, and a pair of skin-facing regions 63 covering the skin-facing surface 15. The non-skin-facing region 59 is disposed at the center of the core-covered sheet 11C in the short side direction W. An inner layer 16A is disposed between the core-covered sheet 11C in the non-skin-facing region 59 and the absorber core 9A. In the non-skin-facing region 59, the core-covered sheet 11C has: a first surface 29 in contact with the non-core-facing surface 23, a second surface 31 on the opposite side of the first surface 29, a plurality of first grooves 33 recessed in the thickness direction T of the first surface 29, and a plurality of second grooves 35 recessed in the thickness direction T of the second surface 31. A pair of side regions 61 are continuously arranged at both ends of the short side direction W of the non-skin-facing region 59. A pair of skin-facing regions 63 are continuously arranged at the ends of the short side direction W of each of the pair of side regions 61. The core-covering sheet 11C covers the non-skin-facing surface 17 and the inner layer 16A together with the non-skin-facing region 59, and covers both sides of the absorbent core 9A with the pair of side regions 61 respectively. When the pair of skin-facing regions 63 are overlapped with the skin-facing surface 15, the pair of skin-facing regions 63 are joined to each other on the skin-facing surface 15.

[0097] The core-coating sheet is not limited to covering the entire absorbent core 9A, including the non-skin-facing side 17; it may also cover only the non-skin-facing side 17 or only the skin-facing side 15. The core-coating sheet may also cover the skin-facing side 15 and the non-skin-facing side 17, excluding the sides of the absorbent core 9A.

[0098] Figure 8This is a partially enlarged cross-sectional view of the absorber 7D of a variation (3) of the first embodiment. The core-covering sheet 11D has an upper core-covering sheet 12C covering the skin-facing surface 15. The upper core-covering sheet 12C has an inner layer 16A facing the absorber core 9A and an outer layer 18A disposed on the side of the inner layer 16A opposite to the absorber core 9A. The outer layer 18A is in contact with the top sheet 3. In this case, bodily fluids that drain onto the surface of the top sheet 3 and permeate through the top sheet 3 reach a third diffusion space between the top sheet 3 and the outer layer 18A, and also reach a second diffusion space between the outer layer 18A and the inner layer 16A through the outer layer 18A. The bodily fluids then reach a first diffusion space between the inner layer 16A and the absorber core 9A through a plurality of openings 27 (not shown in this figure) of the inner layer 16A. Through the diffusivity of the inner layer 16A, the bodily fluids diffuse inside the inner layer 16A, in the first diffusion space, and in the second diffusion space, respectively. Furthermore, the bodily fluid diffuses through the third diffusion space having the second groove 35. Therefore, the same effect as the first embodiment described above can be obtained.

[0099] The openings in the inner layer can also be formed, for example, by inserting a needle along the thickness direction of the inner layer. The inner layer with pre-formed openings can also be overlapped with an outer layer having a first and a second groove, and used as a core-coated sheet.

[0100] In the first embodiment, the case where the absorbent material is a disposable diaper was described, but the present invention is not limited thereto. Examples of absorbent materials include absorbent materials that primarily absorb urine, such as urination pads and animal diapers, and absorbent materials that primarily absorb menstrual blood, such as sanitary napkins and panty liners.

[0101] 2. Second Implementation Method

[0102] The absorbent article of the second embodiment differs from that of the first embodiment in that the core-coating sheet is different. The same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted. It should be noted that... Figure 9 The core-clad sheet shown only shows the lower core-clad sheet, but it can also be shown as... Figure 8 The example shown is applied to the upper core-coated sheet.

[0103] Figure 9The core-covered sheet 11E shown includes a lower core-covered sheet 14C comprising an inner layer 16B and an outer layer 18D. The outer layer 18D has a first surface 29 and a second surface 31. The first surface 29 has a plurality of first grooves 33, and the second surface 31 has a plurality of second grooves 35. A first ridge 37 protruding from the first surface 29 in the thickness direction T is provided between each other in the first grooves 33. The first grooves 33 and the first ridges 37 extend in a direction parallel to the long side direction L and are alternately arranged at predetermined intervals in the short side direction W. The first grooves 33 have a first bottom 65 at the center in the short side direction W. A recess 67 is formed in the first bottom 65. The recess 67 is recessed from the first bottom 65 in the thickness direction T and is discontinuously arranged in the long side direction L. Each recess 67 has a peripheral wall portion 68 and a second bottom 71. The peripheral wall portion 68 has a pair of first peripheral wall portions 69 extending along the long side direction L and facing each other, and a pair of second peripheral wall portions 70 extending along the short side direction W and facing each other.

[0104] The peripheral wall portion 68 may also have a hole 72 that penetrates the peripheral wall portion 68 and leads to the second surface 31. Since body fluid can transfer from the first surface 29 side of the outer layer 18D to the second surface 31 side through the hole 72, the transfer of body fluid from the first surface 29 side of the outer layer 18D to the second surface 31 side can be promoted. The hole 72 is formed in the first peripheral wall portion 69 at a position near the second bottom 71 of the recess 67, and there are two holes 72 in each recess 67. The hole 72 is not provided in the second peripheral wall portion 70. The case where the hole 72 is provided in a pair of first peripheral wall portions 69 has been described, but it can also be provided in a pair of second peripheral wall portions 70, or it can be provided in any one of the peripheral wall portions 68.

[0105] On the first surface 29 side, the distance from the height of the first bottom 65 to the height of the upper surface side of the second bottom 71 (hereinafter referred to as the "upper surface side recess depth") is preferably 10-80% of the height of the upper surface side ridge, more preferably 15-70%, and even more preferably 20-60%. If the upper surface side recess depth is within the above range, sufficient space for storing bodily fluids can be ensured within the recess 67. The length of the long side L of the recess 67 is preferably 0.25-5 mm, more preferably 0.5-3 mm, and even more preferably 0.75-2 mm. The length of the short side W of the recess 67 depends on the spacing of the upper surface side ridges, but is preferably 0.25-5 mm, more preferably 0.5-3 mm, and even more preferably 0.75-2 mm. If the lengths of the long side L and / or the short side W of the recess 67 are within the above range, the effect of temporarily storing bodily fluids that have permeated the absorbent core in the recess 67 can be fully utilized. The depth of the recess on the upper surface side, the length L of the recess 67 in the long side direction, and the length W of the recess 67 in the short side direction are measured using a two-dimensional laser displacement meter. For example, a high-precision two-dimensional laser displacement meter from Keyence Corporation, specifically the LJ-G series (model: LJ-G030), can be cited as a two-dimensional laser displacement meter.

[0106] The pore 72 opens toward the second groove 35 adjacent to the recess 67. The second groove 35 functions as a liquid transport channel, thus facilitating the transfer of bodily fluids from the first surface 29 to the second surface 31 and from the second surface 31 back to the first surface 29. As a result, the absorbent article can promote the diffusion of bodily fluids in the in-plane direction of the outer layer 18D. The pore 72 is preferably not formed by melting the thermoplastic synthetic fibers of the outer layer 18D. When the thermoplastic synthetic fibers are melted and cut, the fiber diameter increases due to the melting and rounding of the fiber ends. Consequently, capillary action is difficult to occur at the periphery of the pore 72. Therefore, it is preferable to form the pore 72 by breaking the thermoplastic synthetic fibers. Preferably, the internal space of the pore 72 is a mixture of fibers anchored within it and some protruding fibers, rather than a completely open space. The porosity of the internal space of the pore 72 is preferably 1–50%, more preferably 1.5–35%, and even more preferably 2.5–20%. If the porosity of the internal space of the hole 72 is within the above-mentioned range, the effect brought by the hole 72 is sufficient to suppress the reduction in strength of the first peripheral wall portion 69 on which the hole 72 is provided. However, the porosity of the internal space of the hole 72 can be arbitrarily set outside the above-mentioned range depending on the type and purpose of the absorbent article according to the present invention.

[0107] The inner layer 16B has an inner layer groove 25 that overlaps with the first groove 33. The inner layer 16B has a plurality of openings 27 in the inner layer groove 25. The plurality of openings 27 are spaced at predetermined intervals along the long side direction L, and are arranged in multiple rows from the bottom to the top of the inner layer groove 25. For example... Figure 10 As shown, the openings 27 are respectively positioned on both sides of the short side direction W corresponding to the recess 67. Figure 10 As shown, the openings 27 can also be arranged in 2 rows and 3 columns (6 openings each) on both sides of the short side W of the recess 67.

[0108] The core-coated sheet 11E, when viewed from above, has an outer layer 18D that is recessed in two stages, thus exhibiting high volume recovery in the thickness direction. Therefore, absorbent articles equipped with this core-coated sheet 11E can maintain a high fluid absorption rate even under repeated exposure to large amounts of bodily fluids such as urine. Furthermore, since the recess 67 of the outer layer 18D has an opening facing the absorbent core, the bodily fluid passing through the absorbent core can be diffused using the first groove 33 and the second groove 35, and the bodily fluid can be temporarily stored in the space within the recess 67. The bodily fluid stored in the recess 67 diffuses through the first groove 33 and / or is transferred to the second surface 31 side via capillary action and flows on the second surface 31 side, diffusing inwards towards the outer layer 18D. The bodily fluid transferred to the second surface 31 side, after diffusion, again passes through the outer layer 18D to the first surface 29 side, and is transferred between the inner layer 16B and the absorbent core through the opening 27 and absorbed by the absorbent core.

[0109] The core-coated sheet of this embodiment can be passed through Figure 5 In the manufacturing apparatus 41 shown, the shaping device 49A is replaced with... Figure 11 The forming device 49B shown is manufactured using this method. The forming device 49B includes a pair of upper and lower stretching rollers 48 and 50B. The lower stretching roller 48 has multiple protrusions 55 and multiple grooves 57 disposed between each of the protrusions 55. The protrusions 55 and grooves 57 extend circumferentially and are alternately arranged at certain intervals in the roller width direction. On the other hand, the upper stretching roller 50B has multiple pins 54 on its outer peripheral surface, which are provided to engage with the grooves 57 of the lower stretching roller 48. The pins 54 are arranged at certain intervals in the roller width direction without contacting the protrusions 55 of the upper stretching roller 50B, and are arranged approximately in a straight line at certain intervals along the outer peripheral surface in the circumferential direction of the roller. Alternatively, the upper stretching roller 50B may have multiple pins 54 arranged in an alternating pattern on its outer peripheral surface.

[0110] In the shaping process, the lower stretching roller 48 presses the portion of the protrusion 55 that contacts the outer continuous body 118 toward the upper stretching roller 50B, thereby shaping the first ridge 37 (second groove 35). On the other hand, a plurality of pins 54 arranged in a row in the circumferential direction on the upper stretching roller 50B press the inner continuous body 116 that contacts the front end of the pin 54 into the same groove 57 of the lower stretching roller 48. At this time, the portion of the inner continuous body 116 and the outer continuous body 118 that is pulled into the groove 57 in a non-contact state with the pin 54 becomes the core-facing groove 24. In addition, since the portion that contacts the front end of the pin 54 is forcefully pressed into the groove 57 and shaped, the first ridge 37 and the first groove 33 form a recess 67, which has a first peripheral wall portion 69 extending along the long side direction L, a second peripheral wall portion 70 extending along the roller width direction, and a second bottom 71. It should be noted that when the second bottom 71 of the recess 67 is formed, the front end of the pin 54 presses the abutting portion of the outer continuous body 118 into the groove 57 while the upper stretching roller 50B and the lower stretching roller 48 are biting into the inner continuous body 116 and the outer continuous body 118.

[0111] In the outer continuous body 118, the portions that contact the two ends of the front end of the pin 54 in the width direction (roller width direction) are also subjected to tension generated when the outer continuous body 118 is pressed upward toward the stretching roller 50B by the protrusion 55. This tension causes the pin 54 to push apart the thermoplastic synthetic fibers forming the first peripheral wall portion 69, or to break the fibers to form broken fibers with broken ends. As a result, a hole 72 containing the broken ends of the broken fibers is formed in the recess 67. It should be noted that a portion of the thermoplastic synthetic fibers remain in the internal space of the hole 72, while the broken ends of a portion of the broken fibers protrude into the internal space. Here, the hole 72 is formed in the direction of the conveying direction MD of the outer continuous body 118, that is, the rotation direction of the stretching roller 48, which is the direction in which the first ridge 37 and the first groove 33 extend. Therefore, the hole 72 is also formed in the first peripheral wall portion 69 in the direction in which the first ridge 37 and the first groove 33 extend. Although the case where the recess 67 is formed into a generally rectangular parallelepiped shape has been described, the shape of the recess 67 can be any shape such as cylindrical or prismatic.

[0112] In the case where the inner continuous layer 116 is formed of paper towel and the outer continuous layer 118 is formed of spunbond nonwoven fabric, the elongation of the paper towel is smaller than that of the spunbond nonwoven fabric. Therefore, since the inner continuous layer does not elongate as much as the outer continuous layer 118, it is torn at the point where the pin 54 abuts. Thus, particularly in the portion of the outer continuous layer 118 where the recess 67 is formed, the cellulose fibers cannot follow the deformation of the outer continuous layer 118, causing them to break. This partially creates cracks, forming multiple openings 27 in the inner continuous layer 116. It should be noted that some cellulose fibers remain embedded within the internal space of the openings 27, while the broken ends of some of the broken cellulose fibers extend into the internal space. Figure 9 as well as Figure 10 The diagram illustrates a case where the opening 27 is discontinuous along the long side direction L, that is, partially formed at the position corresponding to the recess 67. However, it is not limited to this case; openings can also be formed between the recesses 67.

[0113] 3. Third Implementation Method

[0114] The absorbent article of the third embodiment differs from that of the first embodiment in that its absorbent core is different. The absorbent core of the third embodiment has a groove. The groove can extend along the long side direction L or the short side direction W, and can extend in a straight line, a non-straight line, or, for example, a curved line. The groove can also be formed as a ring when viewed from above. The groove can also have a main groove. The groove can also have a main groove and a secondary groove. In the following description, "main groove" refers not only to a groove extending in a direction parallel to the long side direction L, but also to a groove extending along the long side direction L. The angle between the main groove and the long side direction L is preferably less than 45°, more preferably less than 30°, and even more preferably less than 15°. The main groove can extend in a straight line, a non-straight line, or, for example, a curved line. In this specification, the width of the main groove refers to the length of the main groove in the direction orthogonal to the direction in which the main groove extends. "Secondary groove" refers not only to a groove extending in a direction parallel or substantially parallel to the short side direction W, but also to a groove extending in a direction other than the long side direction L. When the secondary groove is connected to the main groove, the angle between the connected portion (base end) and the main groove (or the tangent of the main groove) is preferably 45° or more, more preferably 60° or more, and even more preferably 80° or more. The secondary groove can extend in a straight line, a non-straight line, or, for example, a curved line. In this specification, the width of the secondary groove refers to the length of the secondary groove in the direction orthogonal to the direction in which it extends, within the object portion.

[0115] Figure 12 The absorber core 9B shown has the same characteristics as... Figure 1 The absorber 7A shown has the same external shape. That is, the absorber core 9B has a first end portion 121, a constricted portion 141, and a second end portion 131 in sequence along its long side. Figure 13 As shown, the absorbent core 9B includes a skin-side layer 76A on the skin-facing side 15 and a non-skin-facing side layer 78A on the non-skin-facing side 17. The skin-side layer 76A has a plurality of grooves 80A extending through the skin-side layer 76A in the thickness direction T and bases 82A disposed between the plurality of grooves 80A.

[0116] The groove portion 80A has a plurality of main groove portions 79A and a plurality of secondary groove portions 81A. The plurality of main groove portions 79A are recessed from the skin-facing surface 15 toward the non-skin-facing surface 17 along the thickness direction T of the absorbent core 9B and extend along the long side direction L. In the third embodiment, four main groove portions 79A are evenly arranged in the short side direction W, with each portion having an end 84 of the first end portion 121 and an end 85 of the second end portion 131 as its base. The two innermost of these four main groove portions 79A of the first end portion 121 and the second end portion 131 each have a front end at a position closer to the first end portion 12 and the second end portion 13 than the contraction portion 141. The main groove portion 79A has a width that is preferably 0.5 to 3.0 times, more preferably 0.8 to 2.5 times, and even more preferably 1.0 to 2.0 times the thickness of the absorbent body 7A. When the width of the main channel 79A is within the aforementioned range, the main channel 79A easily maintains its water-permeable function after the absorbent article 1 absorbs bodily fluids. The base ends of each of the plurality of secondary channels 81A communicate with the main channel 79A, and each has a front end extending along the short side direction W. The secondary channels 81A extend along the short side direction W from the first end 121 to the constriction 141, and from the second end 131 to the constriction 141, within the inclined range of the main channel 79A. The depth and width of the secondary channels 81A are the same as the depth of the main channel 79A. The secondary channels 81A are generally formed on both sides of the main channel 79A, but in the main channels 79A located at the outermost ends in the short side direction W of the absorbent core 9B, the secondary channels 81A outside the main channel 79A may be omitted. The base 82A has a narrow portion 86 located between the secondary channels 81A and a wide portion 88 located between the main channels 79A.

[0117] In the thickness direction T, the non-skin side layer 78A, being a low weight-per-unit-area portion with a small weight-per-unit-area for highly absorbent polymer particles, has multiple groove-corresponding portions 92 at positions overlapping with multiple groove portions 80A, and multiple base-corresponding portions 94 at positions overlapping with multiple base portions 82A. The non-skin-facing surface 17 of the non-skin side layer 78A is flat. The multiple base portions 82A, the multiple groove-corresponding portions 92, and the multiple base-corresponding portions 94 can also be integrally formed.

[0118] The absorbent core 9B comprises absorbent fibers 93 and superabsorbent polymer particles (SAP) 95, and functions to absorb and retain bodily fluids discharged into the absorbent article 1. The ratio of superabsorbent polymer particles contained in the non-skin side layer (groove corresponding portion 92, base corresponding portion 94) 78A to the total superabsorbent polymer particles contained in the absorbent core 9B is 0% or more and less than 50%, preferably 0% or more and less than 30%, more preferably 0% or more and less than 20%. The average area weight of the absorbent fibers in both the skin side layer 76A and the non-skin side layer 78A is preferably 50 to 250 g / m². 2 More preferably 80–200 g / m 2 The average weight per unit area of ​​the highly absorbent polymer particles in the non-skin side layer 78A is preferably 0–200 g / m². 2 More preferably 0–150 g / m 2 The average weight per unit area of ​​the highly absorbent polymer particles in the skin lateral layer 76A is preferably 100–500 g / m². 2 More preferably, it is 150–400 g / m 2 The average density of the highly absorbent polymer particles in the non-skin side layer 78A (hereinafter referred to as the "first average density") is smaller than the average density of the highly absorbent polymer particles in the skin side layer (base 82A) 6A (hereinafter referred to as the "second average density"). The first average density is, for example, 0 to 0.15 g / cm³. 3 0~0.1g / cm 3 0~0.08g / cm 3 The second average density is, for example, 0.03–0.4 g / cm³. 3 0.04~0.35g / cm 3 0.05~0.3g / cm 3 .

[0119] The absorbent core 9B can be formed, for example, by depositing materials constituting the absorbent core 9B (e.g., pulp and SAP) in a mold including a recess, the recess having a protrusion in the area corresponding to the main groove 79A or the area corresponding to the main groove 79A and the secondary groove 81A. Specifically, it can be formed according to the methods described in Japanese Patent Application Publication Nos. 2010-233839 and 2014-136126, etc., by the same applicant. Specifically, the pulp is pulverized into a cotton-like state using a hammer mill while air is supplied to the forming recess of the suction box, and the layers are stacked. The forming recess has a protrusion corresponding to the groove. After being removed from the forming recess, the absorbent core 9B can be formed by inverting it. The mixing rate of the superabsorbent polymer particles (SAP) can be adjusted by dividing the pulp supply time into a first half and a second half, and changing the SAP supply amount. The first half of the pulp and SAP supply time corresponds to the skin-side layer 76A, and the second half corresponds to the non-skin-side layer 78A. By increasing the amount of SAP supplied during the first half of the pulp and SAP supply time and decreasing the amount of SAP supplied during the second half, it is possible to produce an absorbent core 9B with a groove corresponding to a low unit area weight portion formed in the non-skin-side layer 78A.

[0120] Bodily fluid flowing into the tank 80A is transported from the discharge site to the long side L of the absorbent core 9B via the main tank 79A, and is absorbed into the interior of the absorbent core 9B from the main tank 79A and the secondary tank 81A connected to the main tank 79A. Furthermore, bodily fluid passing through the tank corresponding portion 92 diffuses through the base corresponding portion 94 and is simultaneously drawn up to the base 82A, which contains a large number of highly absorbent polymer particles and has a high density, thus being retained within the highly absorbent polymer particles. In this way, the absorbent article transports bodily fluid to a position on the absorbent core away from the discharge site through multiple tanks, thereby absorbing bodily fluid over a larger area of ​​the absorbent core and suppressing the decrease in absorbency of the absorbent core near the discharge site. Therefore, even with repeated absorption of bodily fluid, by repeatedly performing the above cycle, the absorbent article 1 can maintain the overall absorbency of the absorbent core, such as the absorption rate.

[0121] The absorbent core 9B of the third embodiment is enclosed within a core-coating sheet and used in absorbent articles. The core-coating sheet has an inner layer containing 50% by mass or more cellulose fibers and an outer layer containing 50% by mass or more thermoplastic synthetic fibers. By having an absorbent core with grooves and an inner layer with excellent diffusion properties, the absorbent article can maintain liquid absorbency at a higher level. The absorbent article also has improved deformation resistance due to the inner layer. When an absorbent article with an inner layer is worn on a doll while absorbing artificial urine, and certain movements are performed, the amount of deformation is found to be less compared to conventional absorbent articles without an inner layer.

[0122] The inner layer may also have multiple openings extending along its thickness direction. The outer layer has multiple first grooves recessed in the thickness direction T on a first surface and multiple second grooves recessed in the thickness direction T on a second surface 31. Each of the multiple first grooves and each of the multiple second grooves are alternately arranged at predetermined intervals in a direction parallel to the short side direction W. The inner layer may also be colored a different color from the absorbent core. The colored inner layer can be visually confirmed through the low unit area weight portion of the absorbent. The position of the groove corresponding portion 92 of the absorbent that has not absorbed bodily fluid can be confirmed by the color of the inner layer, which is the groove corresponding portion 92 of the low unit area weight portion. Therefore, when dry, the user can align it by using the low unit area weight portion as a marker. Since the absorbent is wetted by the absorbed bodily fluid after absorption, it is difficult to visually confirm the inner layer through the low unit area weight portion. Therefore, when wet, the user can visually confirm the absorption status of the bodily fluid. Here, the colorant used for coloring the inner layer is not particularly limited, and any colorant known in the art (e.g., pigments, dyes, etc.) can be used. Furthermore, the coloring method of the colorant is not particularly limited; the inner layer can be colored, for example, by applying or printing the colorant, or by including the colorant in the components of the inner layer.

[0123] The absorbent core may also have grooves on the non-skin side layer. Figure 14 The absorbent core 9B' shown has multiple grooves 80A extending through the non-skin side layer 78B in the thickness direction T, and base portions 82B disposed between the multiple grooves 80A as low weight per unit area. The skin side layer 76B has a base corresponding portion 98 and a groove corresponding portion 96 disposed at a position corresponding to the grooves 80A as a low weight per unit area. The average density of the highly absorbent polymer particles in the base portion 82B is preferably 0 to 0.15 g / cm³. 3 More preferably 0–0.1 g / cm³ 3 The average density of the highly absorbent polymer particles in the corresponding portion 96 of the groove is preferably 0 to 0.15 g / cm³. 3 More preferably 0–0.1 g / cm³ 3 The average density of the highly absorbent polymer particles corresponding to the base portion 98 is preferably 0.1 to 0.3 g / cm³. 3 More preferably, it is 0.1–0.2 g / cm³. 3 The absorbent core 9B' is manufactured using the same method as the absorbent core 9B. After being removed from the molding recess, it is kept in its original orientation without being upside down, thus obtaining the absorbent core 9B'. The third embodiment can be combined with the first embodiment or the second embodiment described above, and by combining them, the same effect as the first embodiment can be obtained.

[0124] 4. Evaluation

[0125] Absorbent articles corresponding to the above-described embodiments were actually manufactured and evaluated. Hereinafter, embodiments are shown to illustrate the present invention, but the present invention is not limited to these embodiments.

[0126] (1) Sample

[0127] [Lower core-covered sheet A]

[0128] Hydrophilic polypropylene spunbond (PPSB) nonwoven fabric (unit area weight: 15g / m²) 2 ) as raw material, used Figure 5 as well as Figure 11 The manufacturing apparatus 41 shown is used to process the lower core-covered sheet A. Specifically, the polypropylene spunbond nonwoven fabric is preheated with a pair of heating rollers with an outer peripheral surface temperature of 90-95°C, and then shaped by a pair of stretching rollers. The nonwoven fabric is conveyed at a speed of 150 m / min. The shaped nonwoven fabric has multiple first grooves and second grooves, and has multiple grooves on the surface that abuts against the stretching rollers. Figure 9 The recesses shown are correspondingly recessed. The aforementioned plurality of first grooves and second grooves extend continuously from one end edge of the core-covering sheet to the other end edge. In the shaped nonwoven fabric, the side having the plurality of recesses corresponds to the core-facing side of the sheet in the absorbent article. The shaped nonwoven fabric is cut to a size of 355mm × 140mm to produce a lower core-covering sheet A. As determined by electron microscopy, on the upper surface side of the lower core-covering sheet A, the height from the bottom of the continuous first groove to the top of the continuous first ridge is 1.0mm, and the interval between the tops of adjacent first ridges is 1.0mm. The recesses have a generally cuboid space, and the depth of the recesses is approximately 0.2mm.

[0129] [Lower core-covered sheet B]

[0130] Paper towels made from wood pulp, which is a cellulose fiber (weight per unit area: 16g / m²) 2 A lower core covering sheet (355mm × 140mm) is used as the inner layer, and the aforementioned lower core covering sheet A is superimposed on the inner layer to form the lower core covering sheet B. The tissue paper of the lower core covering sheet B is not shaped.

[0131] [Lower core-covered sheet C]

[0132] Paper towels made from wood pulp, which is a cellulose fiber (weight per unit area: 16g / m²) 2 As the inner continuous layer 116, hydrophilic polypropylene spunbond (PPSB) nonwoven fabric (unit area weight: 15g / m²) is used. 2 As the outer continuum 118, using Figure 5 as well as Figure 11The manufacturing apparatus 41 shown is used for processing. The specific conditions are the same as those for the lower core-covered sheet A described above. The two overlapping nonwoven fabrics being shaped are held in a state where tissue paper and polypropylene spunbond nonwoven fabric overlap, having multiple core-facing grooves and non-core-facing grooves (second grooves). Regarding the core-facing grooves, the inner groove of the tissue paper overlaps with the first groove of the polypropylene spunbond nonwoven fabric. The inner and outer continuous layers have multiple equivalent... Figure 9 The opening shown is equivalent to the recess. The nonwoven fabric to be shaped is cut to a size of 355mm × 100mm to make the lower core covering sheet C.

[0133] [Lower core-covered sheet D]

[0134] In the process of making the lower core covering sheet C, two overlapping nonwoven fabrics are shaped, and a tissue is peeled from the polypropylene spunbond nonwoven fabric. The tissue is cut into 355mm × 100mm pieces, and the polypropylene spunbond nonwoven fabric is cut into 355mm × 140mm pieces. The tissue is then overlapped again on the polypropylene spunbond nonwoven fabric with their short sides aligned at their centers to create the lower core covering sheet D. Because the tissue is peeled from the polypropylene spunbond nonwoven fabric in one step, the inner groove of the tissue and the first groove of the polypropylene spunbond nonwoven fabric are offset and do not overlap.

[0135] [Upper core-covered sheet]

[0136] Hydrophilic polypropylene spunbond (PPSB) nonwoven fabric (unit area weight: 15g / m²) 2 Cut the sheet to 355mm×100mm or 355mm×140mm and make two sizes of upper core covering sheet D.

[0137] like Figure 2 As shown, when the lower core-covering sheet covers the side of the absorbent core from the non-skin-facing side, an upper core-covering sheet with dimensions of 355mm × 100mm is used. This upper core-covering sheet covers the skin-facing side, and the lower and upper core-covering sheets are joined on the skin-facing side. For absorbents joined on the skin-facing side, in Table 1 below, the "joint position of the upper and lower core-covering sheets" is indicated as "upper surface side".

[0138] like Figure 7A As shown, when the upper core cover sheet covers the side of the absorbent core from the skin-facing side, an upper core cover sheet with dimensions of 355mm × 140mm is used. The lower core cover sheet covers the non-skin-facing side, and the upper and lower core cover sheets are joined on the non-skin-facing side. For absorbents joined on the non-skin-facing side, in Table 1 below, the "joint position of the upper and lower core cover sheets" is indicated as "lower surface side".

[0139] [Absorption Core A]

[0140] While using a hammer mill to pulverize absorbent fibers (pulp) into a cotton-like state, air is supplied to a forming recess with dimensions of 335mm × 100mm (long side × short side) in the suction box. The fibers are then stacked to achieve the unit area weight listed in Table 1. After being removed from the forming recess, the core is formed by inverting the core. The mixing ratio of superabsorbent polymer particles (SAP) is adjusted by dividing the pulp supply time into a first half and a second half, and varying the amount of SAP supplied. The first half of the pulp and SAP supply time corresponds to the skin side layer, and the second half corresponds to the non-skin side layer. By making the SAP supply amounts the same in both the first and second halves, a uniformly mixed core A is obtained.

[0141] [Absorbing Core B]

[0142] Absorbent core B, which has grooves on the skin-facing side, is manufactured using the same steps as absorbent core A, except that it employs molding recesses with protrusions corresponding to the grooves. The 100 / 0 mixing ratio of highly absorbent polymer particles (SAP) in the skin-side layer and the non-skin-side layer is achieved by layering the components, supplying the total amount of SAP in the first half and not supplying SAP in the second half. This results in a product with a material in the skin-side layer equivalent to... Figure 12 The absorber core B of the groove shown is located in the groove section. The short side length of the main groove section is 4 mm, the short side length of the secondary groove section is 6 mm, and the long side length of the secondary groove section is 4 mm.

[0143] [Absorbent Items]

[0144] An absorbent core is fabricated by covering the absorbent core with a lower core-covering sheet disposed on the non-skin-facing side and an upper core-covering sheet disposed on the skin-facing side. The thickness of the absorbent core is adjusted by stamping the absorbent core using a hydraulic press. Then, a liquid-permeable sheet (hot-air nonwoven fabric) is attached to the skin-side layer of each absorbent core, and a liquid-impermeable sheet (polyethylene film) is attached to the non-skin-facing side layer. Thus, simple absorbent articles of Examples 1-5, Comparative Example 1, and Reference Example 1 are produced.

[0145] (2) Test methods

[0146] The absorbent article samples obtained by the following test methods are presented in Table 1 below, along with the structure of the absorbent.

[0147] [Absorption Test]

[0148] (1) Mark a cross at the center position A along the long side of the absorbent article, and then mark a cross at position B 50 mm from the ventral side along its long side. Place the absorbent article in a U-shaped device that is approximately U-shaped when viewed from the side. It should be noted that the absorbent article is placed in the U-shaped device such that the center position A along the long side of the absorbent is aligned with the center (lowest position) of the U-shaped device.

[0149] <First Cycle>

[0150] (2) At position B of the absorbent, inject 80 mL of artificial urine from the burette at a rate of 80 mL / 10 seconds (first time).

[0151] (3) The time from the first injection of artificial urine to the disappearance of artificial urine in the U-shaped device is recorded as the absorption time (80 mL).

[0152] <Second Cycle>

[0153] (4) Ten minutes after the first artificial urine injection, inject 80 mL of artificial urine (second injection) from the burette at position B of the absorbent at a rate of 80 mL / 10 seconds.

[0154] (5) The time from the second injection of artificial urine to the disappearance of artificial urine in the U-shaped device is recorded as the absorption time (160 mL).

[0155] <Third Cycle>

[0156] (6) Repeat steps (4) and (5) to determine the absorption time (240 mL).

[0157] It should be noted that artificial urine is prepared by dissolving 200g of urea, 80g of sodium chloride, 8g of magnesium sulfate, 3g of calcium chloride, and about 1g of pigment: Blue No. 1 in 10L of ion-exchange water.

[0158] [Table 1]

[0159]

[0160] In Examples 1-5, the core-coated sheet has an inner layer and an outer layer. The inner layer contains more than 50% by mass of cellulose fibers, and the outer layer contains more than 50% by mass of thermoplastic synthetic fibers. It has a plurality of first grooves recessed in the thickness direction on a first surface and a plurality of second grooves recessed in the thickness direction on a second surface. Each of the plurality of first grooves and each of the plurality of second grooves is alternately arranged at a predetermined interval. Comparing Examples 1-5 with Comparative Example 1, it is evident that by having an inner layer in the core-coated sheet, the absorption time in the third cycle is shortened. The inner layers of Examples 1-4 have a plurality of openings, but the inner layers of Examples 5 and Reference Example 1 do not have openings. Comparing Examples 1 and 2 with Reference Example 1, it is confirmed that by having openings in the inner layer, the absorption time in the third cycle is shortened. The absorbent cores of Examples 1 and 2 do not have grooves, but the absorbent cores of Examples 3 and 4 do have grooves. Comparing Examples 1 and 2 with Examples 3 and 4, it is confirmed that by having grooves in the absorbent core, the absorption time in the third cycle is further shortened. The inner layer of Example 5 does not have openings, but the absorbent core has grooves. Compared with Reference Example 1, Example 5 confirms that by giving the absorbent core a groove, the absorption time is significantly shortened.

[0161] Explanation of reference numerals in the attached figures

[0162] 1 Absorbent Item

[0163] 3 top films

[0164] 5 back pieces

[0165] 7A-7D absorbers

[0166] 9A and 9B absorption cores

[0167] 11A~11E core-coated sheets

[0168] 15 Skin-to-Skin Face

[0169] 16A, 16B inner layers

[0170] 17 Non-skin-to-skin face

[0171] 18A, 18D outer layer

[0172] 21-core phased surface

[0173] 23 Non-core facing surfaces

[0174] 25 inner groove

[0175] 27 opening

[0176] 29 First page

[0177] 31 Second page

[0178] 33 First Slot

[0179] 35 Second Slot

[0180] 76A, 76B Skin Lateral Layer

[0181] 78A, 78B Non-skin side layer

[0182] 80A slot

[0183] 82A base

Claims

1. An absorbent article, said absorbent article comprising: Liquid-permeable top sheet; Liquid-impermeable backing sheet; as well as An absorber, disposed between the top sheet and the back sheet, in, The absorber includes: An absorbent core having a skin-facing surface and a non-skin-facing surface opposite to the skin-facing surface, and having a long side direction, a short side direction, and a thickness direction; and A core-coated sheet, wherein the core-coated sheet is disposed on the non-skin-facing side. The core-coated sheet has an inner layer and an outer layer. The inner layer comprises more than 50% by mass of cellulose fibers and has a core-facing surface in contact with the absorbent core, a non-core-facing surface opposite to the core-facing surface, a plurality of openings extending from the core-facing surface to the non-core-facing surface, and a plurality of inner layer grooves recessed along the thickness direction on the core-facing surface. The outer layer comprises more than 50% by mass of thermoplastic synthetic fibers and has a first surface in contact with the non-core facing surface, a second surface opposite to the first surface, a plurality of first grooves recessed in the thickness direction on the first surface, and a plurality of second grooves recessed in the thickness direction on the second surface. Each of the plurality of first slots and each of the plurality of second slots are arranged alternately at a predetermined interval. Each of the plurality of first slots and each of the plurality of second slots extends in a direction parallel to the long side direction and is alternately arranged in a direction parallel to the short side direction at predetermined intervals. Each of the plurality of inner grooves extends in a direction parallel to the long side and is arranged at predetermined intervals in a direction parallel to the short side. The core-coated sheet has the following characteristics: A first diffusion space, the first diffusion space having the inner layer groove, is formed between the absorber core and the inner layer; A second diffusion space, having the first groove, is formed between the inner layer and the outer layer, overlapping the inner layer groove; and A third diffusion space, wherein the third diffusion space has the second groove. The plurality of openings are connected along the long side, and multiple rows are arranged between the bottom and top of the inner layer groove. The outer layer and the absorbent core are joined together through the plurality of openings.

2. The absorbent article as claimed in claim 1, wherein, The non-core facing surface and the first surface are not joined together.

3. The absorbent article as described in claim 1 or 2, wherein, The inner layer is a paper towel, and the outer layer is a spunbond nonwoven fabric.

4. The absorbent article as claimed in claim 3, wherein, The inner layer and the absorbent core are joined by a hot melt adhesive.

5. The absorbent article as claimed in claim 1 or 2, wherein, The absorbent core has a low weight-per-unit-area portion where the weight-per-unit-area of ​​the absorbent material is smaller than that of the surrounding material. The inner layer is colored a different color than the absorbent core.

6. The absorbent article as claimed in claim 1, wherein, The inner layer has each of the plurality of openings formed in each of the plurality of inner layer grooves.

7. The absorbent article as claimed in claim 1 or 2, wherein, The absorbent core includes: a skin-facing side layer containing the skin-facing surface and a non-skin-facing side layer containing the non-skin-facing surface. The skin side layer or the non-skin side layer has: Multiple grooves, the multiple grooves including multiple main grooves extending along the thickness direction; and Multiple bases, Each of the plurality of slots and each of the plurality of bases are arranged alternately.

8. An absorbent article, said absorbent article comprising: Liquid-permeable top sheet; Liquid-impermeable backing sheet; as well as An absorber, disposed between the top sheet and the back sheet, in, The absorber includes: An absorbent core having a skin-facing surface and a non-skin-facing surface opposite to the skin-facing surface, and having a long side direction, a short side direction, and a thickness direction; and A core-coated sheet, wherein the core-coated sheet is disposed on the non-skin-facing side. The absorbent core includes a skin-facing side layer and a non-skin-facing side layer, each skin-facing side layer having a plurality of grooves and a plurality of bases. The plurality of grooves includes a plurality of main grooves extending along the thickness direction. Each of the plurality of grooves and each of the plurality of bases is alternately arranged. The core-coated sheet has an inner layer and an outer layer. The inner layer comprises more than 50% by mass of cellulose fibers and has a core-facing surface in contact with the absorbent core, a non-core-facing surface opposite to the core-facing surface, a plurality of openings extending from the core-facing surface to the non-core-facing surface, and a plurality of inner layer grooves recessed along the thickness direction on the core-facing surface. The outer layer comprises more than 50% by mass of thermoplastic synthetic fibers and has a first surface in contact with the non-core facing surface, a second surface opposite to the first surface, a plurality of first grooves recessed in the thickness direction on the first surface, and a plurality of second grooves recessed in the thickness direction on the second surface. Each of the plurality of first slots and each of the plurality of second slots are arranged alternately at a predetermined interval. Each of the plurality of first slots and each of the plurality of second slots extends in a direction parallel to the long side direction and is alternately arranged in a direction parallel to the short side direction at predetermined intervals. Each of the plurality of inner grooves extends in a direction parallel to the long side and is arranged at predetermined intervals in a direction parallel to the short side. The core-coated sheet has the following characteristics: A first diffusion space, the first diffusion space having the inner layer groove, is formed between the absorber core and the inner layer; A second diffusion space, having the first groove, is formed between the inner layer and the outer layer, overlapping the inner layer groove; and A third diffusion space, wherein the third diffusion space has the second groove. The plurality of openings are connected along the long side, and multiple rows are arranged between the bottom and top of the inner layer groove. The outer layer and the absorbent core are joined together through the plurality of openings.

9. A method for manufacturing a core-coated sheet, comprising an absorber core and an absorber core-coated sheet, wherein... The core-coated sheet comprises: The inner layer comprises more than 50% by mass of cellulose fibers and has a core-facing surface, a non-core-facing surface opposite to the core-facing surface, a plurality of openings extending from the core-facing surface to the non-core-facing surface, and a plurality of inner layer grooves recessed in the core-facing surface along the thickness direction. The outer layer comprises more than 50% by mass of thermoplastic synthetic fibers and has a first surface, a second surface opposite to the first surface, a plurality of first grooves recessed in the thickness direction on the first surface, and a plurality of second grooves recessed in the thickness direction on the second surface. A first diffusion space, the first diffusion space having the inner layer groove, is formed between the absorber core and the inner layer; A second diffusion space having the first groove is formed between the inner layer and the outer layer, overlapping the inner layer groove; as well as A third diffusion space, wherein the third diffusion space has the second groove. Each of the plurality of first slots and each of the plurality of second slots are arranged alternately at a predetermined interval. Each of the plurality of first slots and each of the plurality of second slots extends in a direction parallel to the long side and is alternately arranged in a direction parallel to the short side at predetermined intervals. Each of the plurality of inner grooves extends in a direction parallel to the long side and is arranged at predetermined intervals in a direction parallel to the short side. The plurality of openings are connected along the long side, and multiple rows are arranged between the bottom and top of the inner layer groove. The outer layer and the absorbent core are joined together through the plurality of openings. The method for manufacturing the core-coated sheet comprises: The step of preheating the outer continuum composed of the outer layer; and The steps involve conveying the preheated outer continuous body and the inner continuous body composed of the inner layer, with the first surface and the non-core facing surface in contact, between a pair of shaping components having a first shaping component and a second shaping component, to form a plurality of core facing grooves in a state where the core facing surface is recessed along the thickness direction and the first groove and the inner layer groove overlap, a plurality of second grooves in a state where the second surface is recessed along the thickness direction, and a plurality of openings penetrating the inner continuous body from the core facing surface to the non-core facing surface.

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