JP6674249B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article such as a disposable diaper.

  A typical form of the absorbent article includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and a vertically long absorbent body disposed between the sheets. In addition, the absorbent includes a liquid-retentive absorbent core formed by stacking a core forming material including wood pulp and a water-absorbing polymer, and a water-permeable core wrap sheet that covers the absorbent core. Is known. The core wrap sheet functions as a sheet for receiving a core forming material at the time of manufacturing the absorbent body, and plays a role of wrapping and shaping the absorbent core after manufacturing. Regarding the core wrap sheet, for example, Patent Literature 1 discloses a core wrap sheet mainly for the purpose of avoiding the problem that the water-absorbing polymer particles contained in the absorbent core fall out of the absorbent core and leak to the outside of the absorber. It is described that it is preferable to make the maximum pore diameter smaller than 60 μm.

  By the way, as one of the technical problems in the absorbent article, there is an improvement in the ability to absorb loose stool. Loose stool is an excretion that is particularly common in low-month-old infants, and has a higher water content and higher fluidity than ordinary stool. Therefore, if the soft stool absorption performance of the diaper is insufficient, the soft stool may not be absorbed into the diaper, but may leak to the outside through the surface sheet, and the wearer's skin may have a lot of time in contact with the soft stool. This may cause skin irritation. For example, Patent Literature 2 discloses a technique for improving the absorbability of loose stool, which includes a permeable sheet, also called a second sheet, between a top sheet made of a perforated sheet and a core wrap sheet in an absorber. In the article, the magnitude relation of the soft stool transmission speed is set to “surface sheet> transmission sheet> core wrap sheet”, that is, the sheet material closer to the skin of the wearer has a larger soft stool transmission speed.

  Patent Document 3 discloses that an absorbent core in an absorbent article includes a diffusion layer located on a side relatively closer to the wearer's skin, and an absorption storage layer located on a side relatively far from the wearer's skin. It is described that the absorbent storage layer contains a water-absorbent resin composite composed of water-absorbent polymer particles in which fibers are composited. Further, this water-absorbent resin composite includes a portion where fibers are adhered to the surface of the water-absorbent polymer particles. Patent Document 3 discloses a water-absorbent resin composite from the viewpoint of appropriately controlling the adhesive force. It is also described that at least a part of the constituent fibers of the composite is preferably a fiber having a contact angle with water of 60 ° or less. In addition, the technique described in Patent Document 3 avoids inconveniences that may occur when a large amount of a water-absorbing polymer is contained in an absorbent core for the purpose of improving liquid absorbability (reduction in fit, generation of gel blocking, etc.). The main technical task is to take soft stool absorbency into account.

Japanese Patent Publication No. 10-500330 JP 2006-141647 A JP 2005-204817 A

  An object of the present invention is to provide an absorbent article which is excellent in absorbing excrement including loose stool and hardly causes stool leakage.

  The present invention includes an absorbent body and a surface sheet disposed on the skin-facing surface side of the absorbent body, wherein the absorbent body has an absorbent core formed by stacking a core forming material mainly composed of a fiber material. A skin-side core wrap sheet that covers the skin-facing surface of the absorbent core and is mainly composed of a fiber material, and has a longitudinal direction corresponding to the front-rear direction of the wearer and a lateral direction perpendicular to the longitudinal direction. An absorbent article, wherein the skin-facing surface side surface layer portion of the absorbent core has a larger average inter-fiber distance of constituent fibers and a contact angle of constituent fibers with water, as compared to the skin-side core wrap sheet. It is intended to provide a small absorbent article.

  ADVANTAGE OF THE INVENTION According to this invention, the absorptive article which is excellent in absorbency of excrement including loose stool, and is hard to cause stool leakage is provided.

FIG. 1 is an exploded perspective view of a disposable diaper as an embodiment of the absorbent article according to the present invention, in which a resilient member of each part is stretched to expand the disposable diaper in a planar manner, that is, a partially broken plane on a skin facing surface side. FIG. FIG. 2 is a schematic cross-sectional view taken along line II of FIG. 1 (the site where the non-stacking portion exists). FIG. 3 is a schematic plan view of the absorbent core in the diaper shown in FIG. 1 on the skin facing surface side. FIG. 4 is a schematic partial cutaway plan view of the top sheet and the absorbent body on the skin-facing surface side of the diaper shown in FIG. 1, and is a diagram showing an arrangement pattern of through holes in the top sheet. FIGS. 5A and 5B are schematic plan views (corresponding to FIG. 3) of the absorbent core according to another embodiment of the present invention on the skin-facing surface side. 6 (a) to 6 (c) are schematic cross-sectional views of a topsheet and an absorbent body at a portion corresponding to line II in FIG. 1 in another embodiment of the absorbent article of the present invention, respectively. It is. FIG. 7 is a schematic partially broken plan view (a view corresponding to FIG. 4) of the surface sheet and the absorbent body on the skin-facing surface side in still another embodiment of the absorbent article of the present invention. FIG. 8 is a schematic cross-sectional view (corresponding to FIG. 2) of the absorbent article according to still another embodiment of the present invention, taken along a line II in FIG. 1.

  Hereinafter, the absorbent article of the present invention will be described with reference to the drawings based on a disposable diaper which is a preferred embodiment thereof. 1 and 2 show a disposable diaper 1A of the present embodiment. The diaper 1A has an abdominal portion 1F arranged on the abdomen of the wearer and a dorsal portion 1R arranged on the dorsal side when worn, and a crotch portion 1M located therebetween. It extends to the back side part 1R via the crotch part 1M and has a vertical direction X corresponding to the front-back direction of the wearer and a horizontal direction Y orthogonal to this. The abdominal part 1F, the crotch part 1M, and the back part 1R correspond to each area when the diaper 1 is divided into three in the vertical direction X. The crotch portion 1M has an excretion portion opposing portion that is disposed to face both the urine excretion portion and the feces excretion portion (anus) of the wearer when the diaper 1 is worn. In the vertical direction X or in the vicinity thereof.

  The diaper 1A includes a liquid-retentive absorber 4, a liquid-permeable topsheet 2 which is disposed on the skin-facing surface side of the absorber 4 and can come into contact with a wearer's skin when worn. A liquid-impermeable or water-repellent back sheet 3 disposed on the non-skin-facing surface side, and in a plan view as shown in FIG. It is constricted and has a vertically long hourglass shape that is long in one direction, that is, the vertical direction X.

  In the present specification, the “skin-facing surface” is a surface of the absorbent article or a component thereof (for example, the absorbent body 4) that faces the wearer's skin when the absorbent article is worn, that is, a relatively worn surface. The side near the wearer's skin, the "non-skin facing surface" is the side opposite to the skin side when the absorbent article is worn, that is, the side relatively far from the wearer's skin, in the absorbent article or its components. It is the side that is turned to. Further, in the present specification, “at the time of wearing” means a normal proper wearing position, that is, a state where the correct wearing position of the absorbent article is maintained, and the absorbent article is in a state shifted from the wearing position. Case is not included.

  The top sheet 2 and the back sheet 3 each have a size larger than the absorber 4 and extend outward from the periphery of the absorber 4. The back sheet 3 forms the outer shape of the diaper 1A in the unfolded and expanded state as shown in FIG. As the top sheet 2 and the back sheet 3, various ones conventionally used for this type of absorbent article can be used without particular limitation. For example, various types of nonwoven fabrics and apertured films can be used as the top sheet 2, and a resin film or a laminate of a resin film and a nonwoven fabric can be used as the back sheet 3. The back sheet 3 includes, for example, a liquid impermeable film sheet alone and a non-skin facing surface of the film sheet, that is, a form in which an exterior sheet is stacked and arranged on the outer surface side. It is a non-woven fabric.

  Between the top sheet 2 and the back sheet 3 at the waist of the abdomen 1F and the back 1R, that is, at the end in the longitudinal direction X, a thread-like elastic member 31 is extended in the lateral direction Y. As a result, the elastic member 31 contracts to form waist gathers at the waist portion when the diaper 1A is worn. Further, side sheets 34 are disposed on both left and right sides of the diaper 1A along the longitudinal direction X on the top sheet 2 side. The side sheet 34 has an inner edge along the vertical direction X, and an outer edge along the vertical direction X located outside of the inner edge in the horizontal direction Y, and has a flat surface as shown in FIG. As viewed, the inner edge overlaps the absorber 4, and the outer edge extends outward from the side edge along the longitudinal direction X of the absorber 4 in the lateral direction Y and is joined to the back sheet 3. Between the side sheet 34 and the back sheet 3 in the left and right legs arranged around the wearer's leg, a thread-like elastic member 32 is fixed in a stretched state along the vertical direction X. A pair of leg gathers is formed on the leg portion when the diaper 1A is worn by contraction of the elastic member 32. Further, a thread-like elastic member 33 is fixed to the inner edge of the side sheet 34 in an extended state along the longitudinal direction X, so that when the diaper 1A is worn, the elastic member 33 contracts and at least the crotch 1M. A three-dimensional gather is formed at the bottom. The top sheet 2, the back sheet 3, the absorber 4, the elastic members 31, 32, 33, and the side sheet 34 are joined to each other by a known joining means such as a hot melt adhesive.

  The diaper 1A is a so-called unfoldable disposable diaper. As shown in FIG. 1, a pair of fastening tapes 35 are provided on both side edges along the longitudinal direction X of the back side 1R of the diaper 1A. I have. A fastening portion (not shown) made of a male member of a mechanical hook-and-loop fastener is attached to the fastening tape 35. Further, on the non-skin-facing surface of the abdominal portion 1F of the diaper 1A, a fastening region 36 made of a female member of a mechanical surface fastener is formed. The attachment region 36 is formed by attaching a female member of a mechanical surface fastener to the non-skin-facing surface of the back sheet 3 forming the non-skin-facing surface of the abdominal portion 1F by a known joining means, for example, an adhesive or a heat seal. The fastening portion of the fastening tape 35 is detachably fastened.

  The absorbent body 4 includes a liquid-retentive absorbent core 40, a skin-side core wrap sheet 41 covering the skin-facing surface of the absorbent core 40, and a non-skin covering the non-skin-facing surface of the absorbent core 40. The side core wrap sheet 42 is included. The absorbent core 40 and the core wrap sheets 41 and 42 are joined by a known joining means such as a hot melt type adhesive. The absorbent core 40 has a single-layer structure, and has an hourglass shape in which a central portion in the vertical direction X is inwardly confined in a plan view as shown in FIG.

  The absorbent core 40 is a fiber aggregate formed by stacking a core forming material mainly composed of a fiber material. The stacking of the core forming material can be performed by a known method using a known stacking device. Here, “mainly composed of a fiber material” means that the content of the fiber material in the core forming material, that is, the absorbent core 40 is 40% by mass or more. The content of the fiber material is preferably 50% by mass or more based on the total mass of the absorbent core 40, and 100% by mass, that is, the absorbent core 40 may be composed of only the fiber material.

The thickness of the absorbent core 40 under no load (the thickness of the portion other than the non-stacking portion 5 described later) is not particularly limited, but is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, and more preferably Preferably it is 6 mm or less.
The grammage of the absorbent core 40 (the grammage of a portion other than the non-stacking portion 5 described later) is preferably 120 g / m ² or more, more preferably 150 g / m ² or more, and preferably 250 g / m ² or less. And more preferably 220 g / m ² or less.

  Both the skin-side core wrap sheet 41 and the non-skin-side core wrap sheet 42 are mainly made of a fiber material. The meaning of “mainly a fiber material” here is as described above. The skin-side core wrap sheet 41 and the non-skin-side core wrap sheet 42 may be 1) a single continuous sheet or 2) separate sheets. In the diaper 1A, the above item 1) is adopted. That is, in the diaper 1A, one continuous core wrap sheet having a width of twice or more and three times or less the length of the absorbent core 40 in the lateral direction Y is adopted. As shown in FIG. 2, covers the entire area of the skin-facing surface of the absorbent core 40, and extends outward in the lateral direction Y from both side edges along the longitudinal direction X of the absorbent core 40. The portion is rolled down below the absorbent core 40 to cover the entire non-skin-facing surface of the absorbent core 40. In this one core wrap sheet, the portion covering the skin facing surface of the absorbent core 40 is the skin side core wrap sheet 41, and the portion covering the non-skin facing surface of the absorbent core 40 is the non-skin side core wrap. The sheet 42.

  In the case of the above 2), the length in the width direction Y, that is, the width, of the skin-side core wrap sheet 41 and the non-skin-side core wrap sheet 42 may be the same or different. When the widths of the two sheets 41 and 42 are different, either one may be longer. For example, the skin-side core wrap sheet 41 has the same width as the maximum width of the skin-facing surface of the absorbent core 40, that is, has a size capable of covering the entire area of the skin-facing surface of the absorbent core 40. The skin-side core wrap sheet 42 can be wider than the sheet 41. The wide non-skin side core wrap sheet 42 covers the entire non-skin-facing surface of the absorbent core 40 and extends outward in the width direction Y from both side edges along the longitudinal direction X of the absorbent core 40. The extended portion may be wound up on the skin-side core wrap sheet 41 disposed opposite to the skin-facing surface of the absorbent core 40, and may cover both side edges along the longitudinal direction X of the sheet 41. .

  As the fiber material constituting the absorbent core 40, the fiber material usually used for the liquid absorbing element in this type of absorbent article is particularly limited on the premise that the following rules regarding the inter-fiber distance and hydrophilicity are satisfied. Natural pulp such as wood pulp and non-wood pulp; modified pulp such as cationized pulp and mercerized pulp; regenerated cellulose fiber such as rayon; synthetic fiber comprising synthetic resin such as polyethylene resin and polyethylene terephthalate resin A synthetic fiber obtained by subjecting the synthetic fiber to a hydrophilization treatment with a hydrophilic agent such as a surfactant, and the like. One of these fibers can be used alone, or two or more can be used in combination. As the core wrap sheets 41 and 42, for example, paper, nonwoven fabric, or the like can be used, and as the constituent fibers, the same fibers as those of the absorbent core 40 can be used.

  One of the main features of the diaper 1A of the present embodiment is that the skin facing surface side surface portion of the absorbent core 40 has a larger average inter-fiber distance of the constituent fibers and the constituent fibers than the skin side core wrap sheet 41. Has a small contact angle with water. The “skin-facing surface-side surface layer portion of the absorbent core” here is the skin-facing surface of the absorbent core 40, that is, the surface facing the skin-side core wrap sheet 41 and the surface layer portion in the vicinity of the thickness direction thereof, and more specifically. Specifically, it is a region extending within 30% of the maximum thickness of the absorbent core 40 inward in the thickness direction from the skin-facing surface of the absorbent core 40. That is, the skin-facing surface side surface layer of the absorbent core 40 is a portion of the absorbent core 40 that first comes into contact with the excrement of the wearer. The average inter-fiber distance and contact angle are each measured by the following methods. The method for measuring the average inter-fiber distance differs between the absorbent core and the core wrap sheet.

<Method for measuring average fiber-to-fiber distance of constituent fibers of absorbent core>
The average inter-fiber distance of a fiber aggregate such as a nonwoven fabric or paper is determined by an equation based on Wrotnowski's assumption. An expression based on Wrotnowski's assumption is generally used to determine the inter-fiber distance of a fiber assembly. Under Wrotnowski's assumption, the fibers are cylindrical and the fibers are regularly arranged without intersecting.
The inter-fiber distance LS of the absorbent core, which is a kind of fiber aggregate, is determined by the following equation (1) based on the thickness t, basis weight W, fiber density ρ, and fiber diameter D of the constituent fibers of the fiber aggregate.
Three 10 cm × 10 cm samples to be measured are prepared, and the weight of each sample is measured to determine the basis weight W. The thickness under a load of 0.5 g / cm ² was measured using a laser displacement meter (manufactured by KEYENCE CORPORATION, CCD laser displacement sensor LK-080) at any five locations for one measurement sample, for a total of 15 locations. Is the thickness t of the fiber assembly.
The surface of the sample is magnified 250 times with a scanning electron microscope (SEM), the fiber diameter is measured at 15 points, and the average value is defined as the fiber diameter D of the constituent fibers.
The fiber density ρ is an average value obtained from a generally known value of each resin and the resin ratio of the fiber, and is defined as a fiber density ρ.

<Method of measuring average fiber-to-fiber distance of constituent fibers of core wrap sheet>
When the core wrap sheet to be measured has a single-layer structure, the core wrap sheet is determined by the above formula (1) according to the above <Method for measuring average fiber-to-fiber distance of constituent fibers of absorbent core>.
When the core wrap sheet to be measured has a multilayer structure such as an SMS non-woven fabric, it is determined according to the following procedure.
First, the average inter-fiber distance of each layer constituting the multilayer structure is calculated by the above equation (1). At this time, the thickness t, basis weight W, fiber density ρ, and fiber diameter D used in the above formula (1) are those for the layer to be measured, and the thickness t is the thickness direction of the layer to be measured. Is measured by microscopic observation of a cross section along the line. The thickness t, the basis weight W, and the fiber diameter D are the average values of the measured values at a plurality of measurement points, respectively, as in the above <Method of measuring average fiber-to-fiber distance of constituent fibers of absorbent core>. Next, by multiplying the average fiber-to-fiber distance of each layer by the ratio of the thickness of the layer to the total thickness of the multilayer structure, and further summing up the values for each layer obtained in this manner, the desired multilayer structure The average inter-fiber distance of the constituent fibers of the core wrap sheet is determined. For example, in an SMS nonwoven fabric having a three-layer structure including two S layers and one M layer, the two S layers are collectively treated as one layer, and the thickness t of the entire three-layer structure is 0.11 mm. When the thickness t of the S layer is 0.1 mm, the average inter-fiber distance LS of the S layer is 47.8 μm, the thickness t of the M layer is 0.01 mm, and the average inter-fiber distance LS of the M layer is 3.2 μm. The average fiber-to-fiber distance of the constituent fibers of the SMS nonwoven fabric is 43.8 μm [= (47.9 × 0.1 + 3.2 × 0.01) /0.11].

<Measurement method of contact angle>
The fiber is taken out from the measurement object (the skin-facing surface side surface portion or the non-skin-facing side surface layer portion of the absorbent core or the skin-side core wrap sheet), and the contact angle of water with the fiber is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used for measuring the contact angle. The amount of liquid discharged from an ink jet type water droplet discharge unit (Cluster Technology Co., Ltd., pulse injector CTC-25 having a discharge unit hole diameter of 25 μm) is set to 20 picoliters, and a water droplet is dropped just above the fiber. The state of the drop is recorded on a high-speed recording device connected to a horizontally installed camera. The recording device is preferably a personal computer in which a high-speed capture device is incorporated from the viewpoint of performing image analysis later. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water droplets adhering to the fiber taken out of the laminated nonwoven fabric was attached to the attached software FAMAS (software version: 2.6.2, analysis method: droplet method, analysis method: θ / 2 Method, image processing algorithm is non-reflective, image processing image mode is frame, threshold level is 200, curvature correction is not performed), and image analysis is performed to determine the angle between the surface of the water droplet that comes into contact with air and the fiber. Calculate and use as the contact angle. The fiber taken out from the object to be measured is cut into a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and kept horizontal. Two different contact angles are measured for each fiber. N = 5 contact angles are measured to one digit after the decimal point, and a value obtained by averaging the measured values at a total of 10 points (rounded to the second digit after the decimal point) is defined as “contact angle of the constituent fibers with water”. . Such a small value of the contact angle means that the site where the constituent fiber is present has a high degree of hydrophilicity, and a large value of the contact angle means that the site where the component fiber is present is low in the degree of hydrophilicity. I do.

  During the wearing of the diaper 1A, the excrement excreted from the excretion part of the wearer is first received on the skin-facing surface of the topsheet 2, and then, ideally, the topsheet 2 and the skin-side core wrap sheet 41 are removed. The light is sequentially transmitted and absorbed and held by the absorbent core 40. Therefore, in order to enhance the excrement absorbability and to promptly absorb and hold the excrement on the skin-facing surface of the topsheet 2 with the absorbent core 40, the permeability and permeability of the excrement of these members are improved. Is essential. In this regard, in the diaper 1A, the skin-side core wrap sheet 41, which is in contact with the skin-facing surface side of the absorbent core 40 and located on the wearer's skin side of the surface layer in contact with the surface layer, is as described above. As described above, 1) focusing on the “average inter-fiber distance of constituent fibers” as an element that can be a rate-limiting factor of the excrement permeation rate, and comparing the average inter-fiber distance with “skin-side core wrap sheet 41 <absorbent core 40. By defining it as "skin-facing surface side surface layer portion", the excretion rate in the absorbent core 40 can be increased so that the excrement can be held quickly, and 2) it is an index of the hydrophilicity of the constituent fibers. Focusing on the “contact angle of the constituent fibers with water”, the magnitude relation of the contact angle is defined as “skin-side core wrap sheet 41> skin-facing surface-side surface portion of absorbent core 40”, that is, the magnitude of hydrophilicity. The relationship is described as “Skin side core wrap sheet 41 < By defining the skin facing side surface portion "of Osamusei core 40, it is adapted to quickly absorb efficiently pull out excrement excrement from the skin-side core wrap sheet 41. Due to the effects of the above 1) and 2), the diaper 1A can efficiently absorb the excrement on the skin-facing surface of the topsheet 2 into the absorbent core 40. There is no danger of flowing on the skin-facing surface and leaking to the outside, and the excreta diffusion area on the skin-facing surface of the topsheet 2 is smaller than that of the conventional product.

  In particular, the diaper 1A is suitable as a disposable diaper for low-month-old children due to such features. That is, low-month-old infants who are a few months old give loose loose stools, such as diarrhea stool, many times a day with a lot of water and less solid matter, and such loose stools are excreted in conventional disposable diapers. Then, the water in the loose stool is absorbed inside the diaper, but the solid matter in the loose stool remains on the inner surface of the diaper (skin-facing surface of the topsheet) without being absorbed, although it is in a relatively small amount. In the excretion, loose stool is excreted on the solid residue remaining on the inner surface of the diaper. Then, the absorption of loose stool by the second and subsequent excretion is hindered by the solid residue remaining on the inner surface of the diaper, and the loose stool becomes inside the diaper. Before being absorbed, the diaper sometimes leaked to the outside through the inner surface. In addition, such a decrease in soft stool absorbability leads to an increase in the time for the wearer's skin to come in contact with soft stool, which may cause skin irritation. On the other hand, the diaper 1A can quickly absorb the excrement into the inside even if the excrement is soft stool peculiar to a low-month-old child due to the effects of the above 1) and 2). The stool diffusion area on the surface is small, and it is difficult to cause stool leakage and skin irritation.

From the viewpoint of ensuring the effects of 1) and 2) above, the difference in the average fiber-to-fiber distance between the constituent fibers is determined as follows: “Skin-side core wrap sheet 41 <Skin-facing surface side surface layer of absorbent core 40”. In the magnitude relationship of the “parts”, (the latter average inter-fiber distance) − (the former average inter-fiber distance) is preferably 20 μm or more, more preferably 50 μm or more. The upper limit of the difference in the average inter-fiber distance is not particularly limited, but is preferably 400 μm or less.
From the same viewpoint, the difference in the contact angle of the constituent fibers with water is represented by (the former contact angle) − (the former contact angle) − (the skin side core wrap sheet 41> the skin facing side surface layer portion of the absorbent core 40). (The latter contact angle) is preferably 10 ° or more, more preferably 20 ° or more. The upper limit of the difference between the contact angles is not particularly limited, but is preferably 90 ° or less.
From the same viewpoint, the absorbent core 40 has not only the skin-facing surface side surface layer portion but also the entirety, as compared with the skin-side core wrap sheet 41, having a large average inter-fiber distance of the constituent fibers and water of the constituent fibers. Is preferably small.

The skin-facing surface side surface layer of the absorbent core 40, preferably the average inter-fiber distance of the constituent fibers of the whole, is preferably 50 μm or more, more preferably 100 μm or more, and preferably 280 μm or less, more preferably 180 μm or less. It is.
The contact angle of the constituent fibers of the absorbent core 40 on the skin-facing surface side, preferably the whole, with water is preferably 60 ° or less, more preferably 50 ° or less.

  As a preferred example of the absorbent core 40, a structure in which water-absorbing polymer particles are supported on a fiber aggregate made of a natural pulp such as a wood pulp may be mentioned. Another preferable example of the absorbent core 40 includes a structure composed of only a fiber aggregate of regenerated cellulose fibers, that is, a structure not containing a water-absorbing polymer. In general, the regenerated cellulose fiber has a longer fiber length than other fibers, so the fiber aggregate of the regenerated cellulose fiber is bulky, and the average inter-fiber distance is larger than that in the fiber aggregate of the other fibers. Tend. As the regenerated cellulose fiber, a fiber obtained by a viscose method, a copper ammonia method, or an organic solvent method can be used.For example, a rayon fiber formed by a viscose method can be used, and the rayon fiber is fibril. Can also be used.

  The average inter-fiber distance of the constituent fibers of the skin-side core wrap sheet 41 is preferably 15 μm or more, more preferably 30 μm or more, and preferably 100 μm or less, and further preferably 70 μm or less. When the average fiber-to-fiber distance of the constituent fibers of the skin-side core wrap sheet 41, which can be a rate-determining rate of the loose stool transmission rate, is in such a range, the soft stool absorbability can be further improved. That is, if the average fiber-to-fiber distance of the constituent fibers of the skin-side core wrap sheet 41 is too short, the permeation rate of excrement such as loose stool may be reduced. Contains water-absorbing polymer particles, when the water-absorbing polymer particles fall off from the absorbent core 40, there is a possibility that the water-absorbing polymer particles may leak through the skin-side core wrap sheet 41 to the outside.

The contact angle of the constituent fibers of the skin-side core wrap sheet 41 with water is preferably 50 ° or more, more preferably 60 ° or more, and preferably 120 ° or less, and more preferably 90 ° or less.
As the skin side core wrap sheet 41, from the viewpoint of ensuring the function and effect of the above 1) and 2) more reliably and ensuring sufficient strength for practical use, spunbond-meltblown-spunbond (SMS). Nonwovens or spunbonded nonwovens are preferred. In addition, polypropylene fibers are preferable as constituent fibers of the skin-side core wrap sheet 41 made of a nonwoven fabric.

  In the diaper 1A of the present embodiment, as means for improving the absorbability of excrement such as loose stool, the average distance between the constituent fibers and the contact angle of the absorbent core 40 and the skin-side core wrap sheet 41 described above are used. In addition to the specific magnitude relationship, as shown in FIGS. 1 to 3, it is adopted to form the non-stacking portion 5 extending in a predetermined direction (longitudinal direction X) on the skin facing surface of the absorbent core 40. I have. The non-woven fiber portion 5 functions as a flow path for excrement having fluidity such as urine and loose stool, promotes the diffusion of excrement in the surface direction, and can contribute to effective utilization of the absorption performance of the absorbent core 40. .

As shown in FIG. 2, the non-stacking portion 5 in the diaper 1 </ b> A is a through-hole (that is, the basis weight is zero) in which the core forming material constituting the absorbent core 40 does not exist at all. However, in the non-laid portion according to the present invention, in addition to the form of the through-hole such as the non-laid portion 5, a smaller amount (specifically, about 20 g / m ² ) than other regions of the absorbent core is used. (See FIGS. 6 (a) and 6 (b)). This is because the same effect (liquid diffusion action or the like) as that of the non-stacking portion composed of the through-holes is exerted even by the non-stacking portion composed of such a small amount of piled-up portion. In consideration of the liquid diffusion effect and the like, the non-stacking portion made up of the through-holes is more preferable than the non-stacking portion made up of the small amount stacking portion.

  As shown in FIG. 3, the non-stacking portion 5 is 30 mm rearward from the center of the diaper 1 </ b> A in the vertical direction X on the skin-facing surface of the absorbent core 40 (on the side of the dorsal longitudinal end 40 </ b> R of the absorbent core 40). It is formed at least in a square region Q (a region surrounded by a dotted line in FIG. 3) centered on the separated position (the position indicated by reference numeral 40RC in FIG. 3) and having a square of 10 cm in plan view. The position indicated by reference numeral 40RC is a portion facing the anus of the wearer of the diaper 1A, and is a defecation point at which stool such as loose stool is excreted. Since the non-stacking portion 5 is formed in the square region Q on the skin-facing surface of the absorbent core 40, the contact area of the absorbent core 40 with soft stool or the like increases, thereby increasing the stool permeation speed, Stool absorption can be further improved.

The occupied area ratio of the non-stacking portion 5 in the square region Q, that is, the ratio of the total area of the non-stacking portion 5 to the area (100 cm ² ) of the square region Q is preferably 1% or more, more preferably 2% or more. And it is preferably 30% or less, more preferably 15% or less. If the occupied area ratio is too small, the significance of forming the non-stacking portion 5 is poor, and if it is too large, the amount of stool accumulated in the non-stacking portion 5 increases and may return to the topsheet 2 side. However, when the occupied area ratio is in the range of 1% or more and 30% or less, such a concern is greatly reduced.

  In the diaper 1A, as shown in FIGS. 1 and 3, a pair of non-stacking portions 5, 5 extending in the vertical direction X divide the diaper 1A or the absorbent core 40 into two in the horizontal direction Y and in the vertical direction X. It is formed symmetrically with respect to a virtual straight line (not shown) extending. Each non-stacking portion 5 has a rectangular shape in plan view, and its longitudinal direction matches the longitudinal direction X. On the skin-facing surface of the absorbent core 40, the length (namely, the width) of each non-laid portion 5 in the horizontal direction Y is constant over the entire length in the longitudinal direction (vertical direction X). The non-woven fiber portion 5 is arranged such that the absorbent core 40 in the dorsal portion 1R is located at a position in the longitudinal direction X of the abdominal longitudinal end 40F of the absorbent core 40 in the abdominal portion 1F via the crotch portion 1M. Is continued over an inner position in the vertical direction X from the back side vertical end 40R.

The length of the non-stacking portion 5 in the longitudinal direction X is preferably 20 mm or more, more preferably 40 mm or more, and preferably 170 mm or less, more preferably 150 mm or less.
The length, that is, the width, of the non-laid portion 5 in the lateral direction Y is preferably 1 mm or more, more preferably 1.5 mm or more, and preferably 20 mm or less, and more preferably 10 mm or less.
The cross-sectional shape of the non-laid fiber portion 5 in the thickness direction of the absorbent core is not limited to a square shape as shown in FIG. 2, and any shape can be selected, for example, a circular shape may be used.

  The non-stacking portion 5 (non-stacking portion formed of through-holes) intentionally inhibits stacking of the core forming material in the stacking process of the core forming material such as wood pulp during the production of the absorbent core 40. It is a part formed by. The absorbent core 40 having the non-stacking portion 5 can be manufactured according to a conventionally known method of manufacturing an absorbent core. For example, a core forming material supplied by being placed in an air stream is formed on the outer peripheral surface of a rotary drum. In the method of obtaining the absorbent core 40 by sucking and depositing on the formed forming die, the forming die having a predetermined pattern as the forming die, for example, a portion corresponding to the non-stacking portion 5 is located upward as compared with the peripheral portion. It can be manufactured by using a protruding mold. In the absorbent core 40 obtained by such a method, a portion where the core forming material does not exist is the non-stacking portion 5. In addition, as another manufacturing method of the absorbent core 40 having the non-stacking portion 5, an absorbent core having no non-stacking portion is manufactured, and a predetermined portion of the absorbent core is subjected to die cutting or cutting. Although it is also possible to adopt a method of forming a non-stacking portion by performing post-processing such as the above, as described above, the average inter-fiber distance of the constituent fibers of the absorbent core 40 is set to be larger than that of the skin-side core wrap sheet 41. From the viewpoint of increasing the size, it is preferable to use a method of forming the non-stacking portion at the beginning of the manufacturing of the absorbent core as described above, instead of the post-processing of the absorbent core. The absorbent core having the above-mentioned "non-stacking portion composed of a small amount of stacking portion" can also be manufactured according to the above method.

  In the diaper 1A, as shown in FIG. 2, the skin-side core wrap sheet 41 and the topsheet 2 enter the non-stacking portion 5. With such a configuration, the absorbability of excrement including loose stool can be further improved. As shown in FIG. 2, “the sheet has entered the non-stacking portion” means that the sheets 2, 42 are in contact with the entire wall of the absorbent core 40 defining the non-stacking portion 5, as shown in FIG. Not only the state in which the sheets 2 and 42 are present but also the state in which the sheets 2 and 42 exist in the non-stacking portion 5 without contact with the wall portion is essential.

  In the diaper 1A of the present embodiment, as means for improving the absorbability of excrement such as loose stool, the average distance between the constituent fibers and the contact angle of the absorbent core 40 and the skin-side core wrap sheet 41 described above are used. In addition to the specific size relationship and the absorbent core 40 having the non-woven portion 5 on the skin-facing surface, a topsheet 2 having through holes 21 is further employed as shown in FIG. That is, the topsheet 2 has the through-holes 21 at positions overlapping the non-stacking portion 5 on the skin-facing surface of the absorbent core 40. According to such a configuration, excrement such as loose stool existing on the skin-facing surface of the topsheet 2 is promptly transferred to the non-stacking portion 5 of the absorbent core 40 through the through-hole 21, and The transmission speed can be further improved. The shape of the through-hole 21 in plan view is not limited to a circular shape as shown in FIG. 4, and an arbitrary shape such as a square shape can be selected.

  In the present embodiment, as shown in FIG. 4, a plurality of through holes 21 are intermittently provided over the entire length of the topsheet 2 in the vertical direction X at the same position in the horizontal direction Y as that of the non-laying portion 5 in the topsheet 2. In addition to the portion overlapping the non-stacking portion 5 in plan view of the topsheet 2, the outer portion of the non-stacking portion 5 in the vertical direction X (the non-stacking portion 5 is moved in the vertical direction X). The through-hole 21 is also provided in a portion where the virtual extension region is overlapped with the virtual extension region when viewed virtually in plan view). However, the arrangement pattern of the through-holes 21 in the topsheet 2 is not limited to that shown in FIG. 4, and the point is that the through-holes 21 may be arranged in a portion overlapping the non-stacking portion 5. It may be intermittently arranged only in a portion overlapping with the fiber portion 5, or may be arranged in a scattered manner over the entire topsheet 2. Alternatively, the entire portion of the topsheet 2 that overlaps the non-stacking portion 5 in plan view corresponds to the through hole, that is, the pair of non-stacking portions 5, 5 extending in the longitudinal direction X. A pair of rectangular through-holes may be formed in the topsheet 2, but in this case, the above-described form of “the topsheet 2 enters the non-stacking portion 5” will not be possible. .

  The occupancy rate (opening ratio) of the through holes 21 in the topsheet 2, that is, the ratio of the total area of the through holes 21 to the entire area of the portion overlapping the absorbent core 40 in the topsheet 2 is preferably 1% or more, and more preferably 1% or more. Is 5% or more, and preferably 70% or less, more preferably 50% or less. If the opening ratio is too small, the significance of forming the through-holes 21 is insignificant. Conversely, if the opening ratio is too large, the stool that has once passed through the topsheet 2 may return to the topsheet 2 side. When the porosity is in the range of 1% or more and 70% or less, such a concern is greatly reduced.

  5 to 8 show a main part of another embodiment of the absorbent article of the present invention. For other embodiments described later, components different from the disposable diaper 1A of the above embodiment will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. The description of the diaper 1A is appropriately applied to components that are not particularly described.

  FIG. 5 shows another embodiment of the absorbent core according to the present invention, more specifically, a variation of a non-stacking portion that can be formed on the skin-facing surface of the absorbent core. On the skin-facing surface of the absorbent core 40A shown in FIG. 5A, a pair of linear non-laying portions 5X and 5X extending in the vertical direction X and a plurality of (six) linear non-woven fibers extending in the horizontal direction Y are provided. The non-stacking portions 5Y intersect with each other to form a lattice as a whole, and the plurality of non-stacking portions 5Y respectively traverse between a pair of non-stacking portions 5X, 5X and both non-stacking portions 5X. The fibers 5X, X extend outward in the horizontal direction Y from the outer edges extending in the vertical direction X. In the absorbent core 40B shown in FIG. 5B, a pair of arc-shaped non-stacking portions 5Z extending in the vertical direction X and projecting inward in the horizontal direction Y are formed, and the pair of arc-shaped non-stacking portions is formed. The fibers 5Z, 5Z are symmetrically arranged with respect to a virtual straight line (not shown) extending in the vertical direction X by bisecting the absorbent core 40B in the horizontal direction Y. In both the absorbent core 40A and the absorbent core 40B, the non-stacking portion 5X, 5Y or 5Z is formed in a square region Q of 10 cm square in plan view centered on the defecation point 40RC.

  FIG. 6 shows a topsheet and an absorbent body at a portion corresponding to line II of FIG. 1 (a central portion in the vertical direction X) in another embodiment of the absorbent article of the present invention. The non-stacking portion 5 in the diaper 1A is a through-hole in which no core-forming material is present (see FIG. 2), and the non-stacking portion 5 in the diaper 1D shown in FIG. On the other hand, in the diaper 1B shown in FIG. 6 (a) and the diaper 1C shown in FIG. 6 (b), the core forming material exists in the non-stacking portion 5 in a smaller amount than the peripheral portion. In addition, the skin-facing surface of the absorbent core 40 is concavely depressed at the position where the nonwoven fabric portion 5 is formed, whereas the non-skin-facing surface of the absorbent core 40 is flat over its entire area. In the diaper 1A, both the topsheet 2 and the skin-side core wrap sheet 41 enter the non-woven portion 5 (see FIG. 2). Neither of them enters the non-stacking portion 5, and in the diaper 1C and the diaper 1D, only the skin-side core wrap sheet 41 enters the non-stacking portion 5, and the topsheet 2 is non-stacking. It has not entered part 5.

  As described above, the diapers 1A to 1D are mutually different in terms of the form of the non-stacking portion 5 (through holes or depressions), and whether or not the topsheet 2 and the skin-side core wrap sheet 41 enter the non-stacking portion 5. Differently, from the viewpoint of improving the absorbability of excrement including loose stool, the most preferable of these is that the non-stacking portion 5 is a through hole and both sheets 2 and 41 are non-stacking portions 5. The diaper 1A has entered the diaper 1A, and the diaper 1D, the diaper 1C, and the diaper 1B are arranged in a preferred order. That is, from the viewpoint of improving the excrement absorbability, the form of the non-woven fiber portion 5 is more than that of the hollow portion shown in FIG. 6A and FIG. 6) is preferable, and at least the skin side core wrap sheet 41 preferably enters the non-laying portion 5 as shown in FIGS. 6B and 6C. It is more preferable that both the skin-side core wrap sheet 41 and the topsheet 2 enter as shown in FIG.

  The diaper 1E shown in FIG. 7 differs from the diaper 1A shown in FIG. 4 in the form of the through holes 21 in the topsheet 2. That is, in the topsheet 2 of the diaper 1E, in a plan view as shown in FIG. 7, all the non-stacking portions 5 (the entire pair of non-stacking portions 5, 5) on the skin-facing surface of the absorbent core 40 are included. The whole of the portion overlapping with one continuous area is a through hole, and a rectangular opening sheet 22 in a plan view, which covers the entire through hole, is arranged on the skin facing surface of the topsheet 2. The aperture sheet 22 is a sheet separate from the topsheet 2, and has a through hole 21 at a position overlapping the non-stacking portion 5 on the skin-facing surface of the absorbent core 40. The aperture sheet 22 is joined to the topsheet 2 by a known joining means such as an adhesive or heat sealing. The material of the aperture sheet 22 may be the same as or different from that of the topsheet 2.

  In the diaper 1F shown in FIG. 8, another absorbent core 45 separate from the absorbent core 40 is disposed directly on the non-skin-facing surface of the absorbent core 40. That is, the absorbent body 4 in the diaper 1F is configured to include a laminate of an absorbent core 40 as an upper layer and another absorbent core 45 as a lower layer, and the outer surface of the laminate is a skin-side core. It is covered with one continuous sheet having a wrap sheet 41 and a non-skin side core wrap sheet 42. The other absorbent core 45 has a single-layer structure, has the same shape and the same size as the absorbent core 40 in a plan view, and has an hourglass shape in which a central portion in the vertical direction X is inwardly confined in a plan view. It has a long shape in the direction X.

  The skin facing surface side surface portion of the other absorbent core 45 has a smaller average inter-fiber distance of the constituent fibers and the water content of the constituent fibers than the non-skin facing surface side surface portion of the absorbent core 40. Small contact angle. The “skin-facing surface side surface layer portion of the other absorbent core” referred to here is the skin-facing surface of the other absorbent core 45, that is, the surface facing the absorbent core 40 and the surface layer portion near the thickness direction thereof, More specifically, it is a region extending within 30% of the maximum thickness of the other absorbent core 45 from the skin facing surface of the other absorbent core 45 to the inside in the thickness direction. That is, the skin-facing surface side surface portion of the other absorbent core 45 is a portion of the other absorbent core 45 that first comes into contact with the excrement of the wearer. The “non-skin-facing surface side surface layer portion of the absorbent core” refers to the non-skin-facing surface of the absorbent core 40, that is, the surface facing the other absorbent core 45 and the surface layer portion in the vicinity of the thickness direction thereof. Specifically, it is a region extending within 30% of the maximum thickness of the absorbent core 40 inward in the thickness direction from the non-skin-facing surface of the absorbent core 40.

  At least the skin-facing surface side surface portion of the other absorbent core 45 absorbs soft stool due to the small average inter-fiber distance of the constituent fibers in comparison with the non-skin facing surface side surface layer portion of the absorbent core 40. It has excellent retention ability and has strong capillary force due to the small contact angle of water with the constituent fibers, that is, high hydrophilicity. By overlapping without intervening, further improvement in the absorbency of excrement including loose stool can be expected.

From the viewpoint of more reliably exerting the function and effect of the other absorbent core 45, the difference in the average inter-fiber distance of the constituent fibers is determined as follows: "the non-skin-facing surface side surface layer of the absorbent core 40> In the magnitude relationship of the "surface layer portion on the skin facing surface side of the core 45", (the former average inter-fiber distance)-(the latter average inter-fiber distance) is preferably 30 μm or more, more preferably 60 μm or more. The upper limit of the difference between the average inter-fiber distances is not particularly limited, but is preferably 500 μm or less.
From the same viewpoint, the difference in the contact angle of the constituent fibers with water is determined by the magnitude relationship of “the non-skin facing surface side surface layer of the absorbent core 40> the skin facing surface side surface portion of the other absorbent core 45”. (The former contact angle)-(the latter contact angle) is preferably 5 ° or more, more preferably 8 ° or more. The upper limit of the difference between the contact angles is not particularly limited, but is preferably 80 ° or less.
From the same point of view, the other absorbent core 45 has not only the skin-facing surface side surface layer but also the entirety thereof, compared to the non-skin-facing surface side surface layer of the absorbent core 40, the average inter-fiber distance of the constituent fibers. And the contact angle of the constituent fibers with water is preferably small.

The skin-facing surface side surface portion of the other absorbent core 45, preferably the average inter-fiber distance of the constituent fibers of the whole is preferably 30 μm or more, more preferably 50 μm or more, and preferably 150 μm or less, more preferably It is 100 μm or less.
The contact angle of the surface fibers of the other absorbent core 45 on the skin-facing surface side, preferably the whole, of the constituent fibers with water is preferably 45 ° or less, more preferably 40 ° or less.

The other absorbent core 45 can be configured basically in the same manner as the absorbent core 40. As a preferable example of the other absorbent core 45, a structure in which a water-absorbing polymer particle is supported on a fiber aggregate made of natural pulp such as wood pulp is given.
The thickness of the other absorbent core 45 under no load is not particularly limited, but is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, more preferably 6 mm or less.
The basis weight of the other absorbent core 45 is preferably 250 g / m ² or more, more preferably 300 g / m ² or more, and preferably 500 g / m ² or less, more preferably 450 g / m ² or less.

The other absorbent core 45 preferably has a higher water-absorbing polymer content than the absorbent core 40. With such a configuration, the effect of the use of the laminated body of the two absorbent cores 40 and 45 is more reliably exhibited, and further improvement in the absorption of excrement including loose stools can be expected. The difference in the content of the water-absorbing polymer between the two absorbent cores 40 and 45 is represented by (the latter content of the water-absorbing polymer) − (the former) Is preferably 5% by mass or more, more preferably 10% by mass or more.
The content of the water-absorbing polymer in the other absorbent core 45 is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass with respect to the total mass of the other absorbent core 45. Or less, more preferably 60% by mass or less.
Incidentally, the content of the water-absorbing polymer in the absorbent core 40 may be 0% by mass as described above, and the absorbent core 40 is composed of only fiber aggregates such as regenerated cellulose fibers and does not contain the water-absorbing polymer. Is also good.

Although the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately changed. For example, the shape and arrangement of each of the non-stacking portion of the absorbent core and the through-hole of the topsheet are not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention. All the parts of only one embodiment described above can be mutually used as appropriate.
The absorbent article of the present invention is not limited to the deployable disposable diaper as in the above embodiment, but broadly encompasses articles used for absorbing body fluids (urine, menses, loose stools, sweat, etc.) discharged from the human body. , Pants-type disposable diapers, sanitary napkins, sanitary shorts, and the like.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to such Examples.

[Examples 1 to 3 and Comparative Example 1]
According to a conventional method, a deployable disposable diaper having the same basic configuration as the diaper 1A shown in FIGS. 1 and 2 was produced.
An air-through nonwoven fabric having a basis weight of 25 g / m ² was used as a top sheet, and a liquid-impermeable and moisture-permeable polyethylene resin film (containing calcium carbonate) having a basis weight of 20 g / m ² was used as a back sheet. The topsheet does not have the aforementioned “through hole formed at a position overlapping the non-stacking portion of the absorbent core”.
The absorbent core, 1) as a structure obtained by holding the particulate water-absorbing polymer in the fiber aggregate, the total basis weight consisting of a homogeneous mixture of fluff pulp 200 g / m ² and the water-absorbing polymer 186 g / m ² Absorptive core of 386 g / m ² , 2) absorptive core composed only of a fiber aggregate of regenerated cellulose fibers (Toyobo, rayon fiber), or a two-layer absorbent composed of a laminate of the above 1) and 2) A core was used. In Table 1 below, the absorbent core having the single-layer structure is referred to as “upper absorbent core”, and the absorbent core having the two-layer structure is referred to as “upper absorbent core” which is relatively close to the wearer's skin. And a "lower absorbent core" (corresponding to the "other absorbent core"), which is relatively far from the skin of the subject. The total length in the vertical direction (longitudinal direction) of the absorbent core was 360 mm, and the total length (maximum length) in the horizontal direction (width direction) was 110 mm. The absorbent core does not have the non-laid portion.
As the core wrap sheet, an SMS nonwoven fabric having a basis weight of 8 g / m ² or a paper having a basis weight of 14 g / m ² is used, and the entire area of the skin-facing surface and the non-skin-facing surface of the absorbent core is covered with one core wrap sheet. Was coated.

〔Evaluation test〕
For the diapers of each of the examples and comparative examples, the stool diffusion area was evaluated by the following method. The results are shown in Table 1 below.

<Method of measuring stool diffusion area>
The diaper to be measured is spread out in a plane and placed horizontally so that the skin-facing surface side (top sheet side) faces upward, and a portion separated 30 mm rearward from the vertical center of the diaper (the defecation point in FIG. 3). After injecting 10 g of simulated loose stool at a time at a flow rate of 6 g / sec into a portion corresponding to 40RC), a non-water-permeable resin film is superimposed on the injection position, and a weight is further placed on the resin film. By mounting, a pressure of 3 kPa was applied to the injection position for 1 minute. The pressure of “3 kPa” is assumed to be a pressure (pressure resistance) applied to the back of the diaper when a low-aged infant wearing the diaper is lying on his back. The pseudo loose stool used was a suspension prepared by dissolving or dispersing bentonite in water, and had a viscosity of 40 mPa · s and a bentonite concentration of 15% by mass. After the pressure treatment, the weight and the resin film were removed, and the diffusion area of the pseudo loose stool was measured. For each diaper to be measured, three measurement samples were prepared, and the above measurements were performed for each. The average value of the measured values was defined as the stool diffusion area of the diaper. The smaller the stool diffusion area, the better the soft stool absorbency and the higher the evaluation.

1A, 1B, 1C, 1D, 1E, 1F Absorbent articles (disposable diapers)
1F Abdominal part of absorbent article 1M Crotch part of absorbent article 1R Back part of absorbent article 2 Surface sheet 21 Through hole 22 Perforated sheet 3 Back sheet 4 Absorber 40, 40A, 40B Absorbent core 45 Other Absorbent core 41 Skin-side core wrap sheet 42 Non-skin-side core wrap sheet 5, 5X, 5Y, 5Z Non-stacking portion X Vertical direction Y Horizontal direction

Claims (9)

An absorbent core comprising an absorbent body and a surface sheet disposed on the skin-facing surface side of the absorbent body, wherein the absorbent body is formed by stacking a core forming material mainly composed of a fiber material; An absorbent article comprising a skin-side core wrap sheet that covers the skin-facing surface of the core and is mainly composed of a fiber material, and has a vertical direction corresponding to the front-back direction of the wearer and a horizontal direction orthogonal thereto. So,
The fiber material of the absorbent core is at least one selected from the group consisting of natural pulp, modified pulp, regenerated cellulose fiber and synthetic fiber, and the skin-side core wrap sheet is made of paper or nonwoven fabric,
An absorbent article in which the skin facing surface side surface portion of the absorbent core has a larger average inter-fiber distance and a smaller contact angle with water of the constituent fibers than the skin side core wrap sheet.   The skin-facing surface side surface layer portion of the absorbent core has an average fiber-to-fiber distance of at least 20 μm and a contact angle with water of the constituent fibers of at least 10 ° smaller than the skin-side core wrap sheet. Item 2. The absorbent article according to Item 1.   The absorbent article according to claim 1, wherein the skin-side core wrap sheet is made of a spunbond-meltblown-spunbond nonwoven fabric or a spunbond nonwoven fabric.   On the skin facing surface of the absorbent core, a non-stacking portion is formed so as to extend in a predetermined direction in a square area of 10 cm square in plan view centered on a position 30 mm rearward from the longitudinal center of the absorbent article. The absorbent article according to any one of claims 1 to 3, wherein an occupied area ratio of the non-laid fiber portion in the square region is 1% or more and 30% or less.   The absorbent article according to claim 4, wherein the skin-side core wrap sheet and the topsheet enter the non-stacking portion.   The absorbent article according to claim 4, wherein the topsheet has a through hole at a position overlapping the non-stacking portion.   Another absorbent core separate from the absorbent core is disposed directly on the non-skin facing surface of the absorbent core, and the skin facing surface side surface portion of the other absorbent core is The non-skin-facing surface side surface layer of the absorbent core has a smaller average fiber-to-fiber distance and a smaller contact angle with water of the constituent fibers. Goods.   The skin-facing surface side surface portion of the other absorbent core is smaller than the non-skin-facing surface side surface portion of the absorbent core by an average fiber-to-fiber distance of at least 30 μm and water of the constituent fibers. The absorbent article according to claim 7, wherein the contact angle is smaller than 5 °.   The absorbent article according to claim 7, wherein the other absorbent core has a higher content of the water-absorbing polymer than the absorbent core.

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