Absorbent article

Abstract

To suppress backward leakage at second and preceding evacuation.SOLUTION: An absorbent article includes: a groove 23D provided in an uppermost surface of an absorber 23 and extending in a longitudinal direction LD between a crotch part C2 and a back-side part B2; and an absorption sheet 50 between a top sheet 22 and the uppermost surface of the absorber 23. The absorption sheet 50 includes: an upper sheet 51 and a lower sheet 52 having liquid permeability; a housing part 55 for housing highly absorbent polymer particles 53 between the upper sheet 51 and the lower sheet 52; and a junction 54 disposed so as to surround a periphery of the housing part 55. At least one housing part 55 has a width narrower than a width of the groove 23D, where 80% or more of the width overlaps on the groove 23D. When the groove 23D is trisected into an upper part, an intermediate part, and a bottom part in a depth direction while being deployed and absorbing nothing, the absorption sheet 50 is positioned in the upper part of the groove 23D or higher part.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to disposable diapers and absorbent articles including sanitary napkins.

Background Art

[0002] Many of these absorbent articles can absorb more excretory fluid by spreading excretory fluid such as urine more widely. For example, by providing a slit in the absorbent body or by providing a groove extending rearward from the crotch portion on the uppermost surface of the absorbent body, it is common practice to guide the excretory fluid rearward and use the absorbent body more widely for absorption (see, for example, Patent Documents 1 and 2).

[0003] However, when such a groove is provided in the absorbent body, there is a problem that, at the time of excretion for the second time and later, the induction of the excretory fluid by the groove is strongly promoted, making it easier for back leakage (excretory fluid leaking from the rear end of the product) to occur.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, the main problem of the present invention is to suppress back leakage at the time of excretion for the second time and later.

Means for Solving the Problems

[0006] As a result of studying the cause of post-void leakage due to multiple urinations, the inventor of the present invention has found that the following phenomenon is one of the factors. That is, when the absorber is a mixed aggregate of general superabsorbent polymer particles and short fibers, when the excreted liquid is absorbed, the portions adjacent to both sides in the width direction of the groove in the absorber expand in the thickness direction, so that the groove becomes deeper and the induction of the excreted liquid by the groove is strongly promoted. As a result, in the second and subsequent urinations, the backward induction of the excreted liquid becomes excessive, and post-void leakage is likely to occur. The absorbent article described below that solves the above problems is based on such findings.

[0007] <First Aspect> A crotch portion, a front portion and a rear portion extending forward and backward from the front side and the rear side of the crotch portion, respectively, An absorber extending over the crotch portion and the rear portion, A liquid-permeable topsheet provided on the front side of the absorber, It has a groove extending in the front-rear direction over the crotch portion and the rear portion provided on the uppermost surface of the absorber, The region having the groove in the absorber has a lower basis weight than the portions adjacent to both sides in the width direction of the groove in the absorber, The absorber is a mixed aggregate of superabsorbent polymer particles and short fibers, In a disposable diaper, An absorption sheet is provided between the topsheet and the uppermost surface of the absorber, The absorption sheet has a liquid-permeable upper sheet and a lower sheet, a storage portion in which superabsorbent polymer particles are stored between the upper sheet and the lower sheet, and a joining portion disposed so as to surround the storage portion, At least one of the storage portions has a width narrower than the width of the groove, and 80% or more of its width overlaps with the groove, In an unabsorbed deployed state, when the groove is trisected into an upper portion, a middle portion, and a bottom portion in the depth direction, the absorption sheet is located above the upper portion of the groove, An absorbent article characterized by the above.

[0008] (Function and Effect) This absorbent article is provided with an absorption sheet between a topsheet and the uppermost surface of the absorber (the upper surface of the absorber when the absorber is a single layer, and the upper surface of the upper absorber when the absorber is a two-layer structure). In the unabsorbed and unfolded state, when the groove is trisected into an upper part, a middle part, and a bottom part in the depth direction, the absorption sheet is located above the upper part of the groove. Therefore, at the first excretion, a part of the excreted liquid permeates through the absorption sheet and flows into the space between the absorption sheet and the groove, and is guided backward through this space. Further, in the absorption sheet, the superabsorbent polymer particles in the accommodating part swell due to the excreted liquid (while absorbing and retaining the excreted liquid and expanding), filling the accommodating part, and the accommodating part expands and its thickness increases. At this time, since the width of the accommodating part is narrower than the groove and most of it overlaps with the groove, a part or all of the expanded accommodating part enters deeper into the groove than before expansion. As a result, even if the portions located on both sides in the width direction of the groove expand in the thickness direction and the depth of the groove increases, the expanded accommodating part reduces the cross-sectional area of the groove. Therefore, compared with the case where it does not, the increase in the cross-sectional area of the groove during excretion after the second time, that is, the promotion of the induction of excreted liquid is suppressed (the first effect). Also, since the accommodating part filled with swollen superabsorbent polymer particles has a reduced liquid permeability in the thickness direction, the introduction of excreted liquid into the groove during excretion after the second time is suppressed. Therefore, also in this respect, the promotion of the induction of excreted liquid by the groove is suppressed (the second effect). Therefore, as a result of these, it becomes possible to suppress back leakage due to excretion after the second time.

[0009] <Second Aspect> The absorption sheet has a width narrower than the width of the groove, and has a plurality of the accommodating parts, the width of which 80% or more is located above the groove, spaced apart in the front-rear direction. The absorbent article of the first aspect.

[0010] (Function and Effect) When a plurality of accommodating parts that expand so as to enter the groove are provided in a plurality of rows spaced apart in the front-rear direction, even during excretion after the second time, excreted liquid is introduced into the groove from the portion between the accommodating parts adjacent in the front-rear direction above the groove. Therefore, it is preferable because the absorption action and the induction action of excreted liquid through the groove are surely maintained.

[0011] <Third Aspect> The absorption sheet has three or more rows of the accommodating portions arranged in series with a space therebetween in the front-rear direction and with a space therebetween in the width direction. A plurality of accommodating portions belonging to at least one row located in the middle in the width direction among the rows have a width smaller than the width of the groove, and 80% or more of the width overlaps with the groove, and the other accommodating portions do not overlap with the groove. The absorbent article according to the second aspect.

[0012] (Function and Effect) Thus, when there is an accommodating portion that does not overlap with the groove (that is, does not enter the groove), a raised portion is formed on the surface of the topsheet due to the expansion of this accommodating portion, and this raised portion promotes diffusion by blocking the rearward movement of the excreted liquid on the surface of the topsheet. Therefore, the rearward movement of the excreted liquid during the second and subsequent excretions is suppressed.

[0013] <Fourth Aspect> The shapes and volumes of the accommodating portions are all the same. The amount of the superabsorbent polymer particles accommodated in the accommodating portion located at the rearmost part in the front-rear direction is larger than the amount of the superabsorbent polymer particles accommodated in the accommodating portion located at the foremost part in the front-rear direction. The thickness at the maximum expansion of the accommodating portion located at the rearmost part is thicker than the thickness at the maximum expansion of the accommodating portion located at the foremost part. The absorbent article according to the second or third aspect.

[0014] (Function and Effect) By changing the thickness at the maximum expansion of the accommodating portion in this way, the above-described first and second functions are more effectively exhibited.

[0015] <Fifth Aspect> On at least one of the topsheet and the bottom sheet at the site of the accommodating portion, a recess that is recessed outward is formed by embossing. The depth of the recess of the accommodating portion located at the rearmost part is deeper than the depth of the recess of the accommodating portion located at the foremost part. The thickness of the accommodating part located at the rearmost part at the time of maximum expansion is thicker than the thickness of the accommodating part located at the foremost part at the time of maximum expansion. An absorbent article according to the second or third aspect.

[0016] (Function and effect) When a change is made to the thickness of the accommodating part at the time of maximum expansion as in this aspect, the above-described first and second functions are more effectively exhibited.

[0017] <Sixth aspect> The width of the groove is 15 to 40 mm, The width of the accommodating part is 0.8 to 0.95 times the width of the groove, The length of the accommodating part in the front-rear direction is 1.5 to 3.5 times the width of the accommodating part. An absorbent article according to any one of the first to fifth aspects.

[0018] (Function and effect) The width of the groove and the dimensions of the accommodating part can be appropriately determined, but in the normal case, it is preferably within this range.

[0019] <Seventh aspect> The accommodating part has a shape in which the width gradually widens toward the rear side. An absorbent article according to any one of the first to sixth aspects.

[0020] (Function and effect) The shape of the accommodating part can be appropriately determined, but if it has a shape as in this aspect, the excreted liquid that collides with the expanded accommodating part from the front will move rearward while changing its direction toward both sides in the width direction. Therefore, in the accommodating part located in the groove, the excreted liquid that moves rearward in the groove can be diffused to both sides in the width direction, and in the accommodating part located outside the groove, the excreted liquid that moves rearward on the top sheet surface can be diffused to both sides in the width direction. Thus, the rearward movement of the excreted liquid during the second and subsequent excretions, that is, the rear leakage, can be suppressed.

[0021] <Eighth aspect> The absorber comprises a lower absorber which is an integrated mixture of superabsorbent polymer particles and short fibers, and an upper absorber which is provided on the front side thereof and is an integrated mixture of superabsorbent polymer particles and short fibers. In an intermediate region in the front-rear direction including the crotch portion, a slit having a predetermined width that penetrates the upper absorber only or the upper absorber and the lower absorber in the thickness direction extends in the front-rear direction. The upper absorber has a total basis weight of short fibers and superabsorbent polymer particles of 200 to 700 g / m 2 and a weight ratio of superabsorbent polymer particles to short fibers of 50 to 200%. An absorbent article according to any one of aspects 1 to 7.

[0022] (Function and effect) As an absorber, a mixture of short fibers such as pulp fibers and superabsorbent polymer particles is still widely adopted at present. When performing absorption multiple times using such an absorber, it is preferable to form the absorber into a two-layer structure as in this embodiment and increase the weight ratio of the superabsorbent polymer particles in the upper absorber. However, in this case, since the increase amount of the depth of the groove when absorbing excreted liquid becomes large, the induction of the excreted liquid by the groove is particularly strongly promoted. Therefore, the adoption of the aforementioned absorption sheet is particularly significant technically in such a case.

Effect of the Invention

[0023] As described above, according to the present invention, advantages such as being able to suppress back leakage during excretion after the second time are brought about.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Mode for Carrying Out the Invention

[0025] Hereinafter, examples of absorbent articles will be described in detail with reference to the accompanying drawings. Among the terms, the "crotch portion C2" means a portion corresponding to the crotch of the body during use, and depending on the product, it may be in the range from the center or near the center in the longitudinal direction LD of the article to a predetermined front portion as shown in the illustrated form, or it may be a predetermined range in the center in the longitudinal direction LD of the article. When there is a narrow constricted portion 23n in the middle in the longitudinal direction LD of the article or in the longitudinal direction LD of the absorbent body 23, it means a predetermined longitudinal direction LD range with the minimum width portion of one or both of the constricted portions 23n as the center in the longitudinal direction LD. Further, the "front portion F2 (ventral portion)" means a portion anterior to the crotch portion C2, and the "rear portion B2 (dorsal portion)" means a portion posterior to the crotch portion C2.

[0026] Each component member adjacent in the thickness direction is fixed or joined, as necessary, in the same manner as a known diaper, except for the fixing or joining portions described below. The dot pattern portion in the cross-sectional view indicates an adhesive such as a hot melt adhesive as this fixing or joining means. The hot melt adhesive can be applied by known methods such as slot coating, continuous linear or dotted bead coating, spray coating in a spiral, Z-shape, wave shape, etc., or pattern coating (transfer of hot melt adhesive by a relief printing method). Instead of or together with this, at the fixing portion of the elastic member, the hot melt adhesive can be applied to the outer peripheral surface of the elastic member to fix the elastic member to the adjacent member. As the hot melt adhesive, there are, for example, types such as EVA-based, pressure-sensitive rubber-based (elastomer-based), polyolefin-based, polyester-polyamide-based, etc., and it can be used without particular limitation. As the fixing or joining means for joining each component member, means such as material welding by heat sealing or ultrasonic sealing can also be used. In portions where liquid permeability in the thickness direction is required, the component members adjacent in the thickness direction are fixed or joined in an intermittent pattern. For example, when performing such intermittent fixing or joining with a hot melt adhesive, intermittent pattern coating in a spiral, Z-shape, wave shape, etc. can be preferably used, and when applying in a range wider than the coating width by one nozzle, intermittent pattern coating in a spiral, Z-shape, wave shape, etc. can be performed with or without spacing in the width direction. As the joining means for joining each component member, means such as material welding by heat sealing or ultrasonic sealing can also be used.

[0027] In addition, as the nonwoven fabric in the following description, known nonwoven fabrics can be appropriately used according to the part and purpose. As the constituent fibers of the nonwoven fabric, for example, synthetic fibers such as polyolefins such as polyethylene or polypropylene, polyesters, polyamides, etc. (including composite fibers such as core-sheath in addition to single-component fibers), regenerated fibers such as rayon and cupra, natural fibers such as cotton, etc. can be selected without particular limitation, and these can also be used in combination. In order to enhance the flexibility of the nonwoven fabric, it is preferable that the constituent fibers are crimped fibers. Further, the constituent fibers of the nonwoven fabric may be hydrophilic fibers (including fibers made hydrophilic by a hydrophilizing agent), hydrophobic fibers or water-repellent fibers (including fibers made water-repellent by a water-repellent agent). In addition, nonwoven fabrics are generally classified into short fiber nonwoven fabrics, long fiber nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, thermal bond (air-through) nonwoven fabrics, needle-punched nonwoven fabrics, point-bond nonwoven fabrics, laminated nonwoven fabrics (including SMS nonwoven fabrics, SMMS nonwoven fabrics, etc. with a meltblown layer sandwiched between spunbond layers) according to the fiber length, sheet forming method, fiber bonding method, and laminated structure, etc., and any of these nonwoven fabrics can be used.

[0028] Figs. 1 to 4 show a pad-type disposable diaper 200 as an example of an absorbent article. This pad-type disposable diaper 200 has a crotch portion C2 and a front portion F2 and a rear portion B2 extending on both front and rear sides thereof. The dimensions of each part can be determined appropriately. For example, the overall length (length in the front-rear direction) L of the article can be about 350 to 700 mm, and the overall width W1 can be about 130 to 400 mm (however, wider than the width of the absorbent surface of the diaper). In this case, the length in the front-rear direction of the crotch portion C2 can be about 10 to 150 mm, the length in the front-rear direction of the front portion F2 can be about 50 to 350 mm, and the length in the front-rear direction of the rear portion B2 can be about 50 to 350 mm. Also, the width W3 of the crotch portion C2 can be, for example, 150 mm or more, particularly about 200 to 260 mm in the case of adult use.

[0029] This pad-type disposable diaper 200 has a basic structure including an absorber 23 between a liquid-impermeable sheet 21 and a topsheet 22 having liquid permeability.

[0030] On the back side of the absorber 23, the liquid-impermeable sheet 21 is provided so as to slightly protrude from the periphery of the absorber 23. As the liquid-impermeable sheet 21, in addition to a polyethylene film or the like, a sheet having moisture permeability without impairing water barrier properties from the viewpoint of preventing stuffiness can also be used. This water barrier and moisture permeable sheet can be, for example, a microporous sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet and then stretching it in one or two axial directions.

[0031] Also, the outer surface of the liquid-impermeable sheet 21 is covered by an outer sheet 27 made of a non-woven fabric, and this outer sheet 27 protrudes outward from the periphery of the liquid-impermeable sheet 21 with a predetermined overhang width. Various non-woven fabrics can be used as the outer sheet 27. The outer sheet 27 can also be omitted.

[0032] The front side of the absorber 23 is covered by a topsheet 22 having liquid permeability. In the illustrated embodiment, the absorber 23 partially protrudes from the side edge of the topsheet 22, but the width of the topsheet 22 can also be widened so that the side edge of the absorber 23 does not protrude. Various non-woven fabrics can be used as the topsheet 22. One of the preferred non-woven fabrics as the topsheet 22 is an air-through non-woven fabric formed by thermally bonding thermoplastic synthetic fibers.

[0033] An intermediate sheet (not shown) can be interposed so as to contact the back surface of the top sheet 22. This intermediate sheet is provided to prevent the reverse flow of urine absorbed by the absorber 23, and it is desirable to use a material having low water retention and high liquid permeability, such as various non-woven fabrics and mesh films. When the front end of the top sheet 22 is set to 0% and the rear end of the top sheet 22 is set to 100%, the front end of the intermediate sheet is preferably located in the range of 0 to 11%, and the rear end of the intermediate sheet is preferably located in the range of 92 to 100%. Also, the width of the intermediate sheet is preferably about 50 to 100% of the total width W3 of the absorber 23. The intermediate sheet can also be omitted.

[0034] At both ends in the longitudinal direction LD of the pad-type disposable diaper 200, the liquid-impermeable sheet 21, the outer cover sheet 27, and the top sheet 22 extend to both the front and rear sides of the front and rear ends of the absorber 23 and are bonded together, forming an end flap portion EF where the absorber 23 does not exist. At both side portions of the pad-type disposable diaper 200, the liquid-impermeable sheet 21 and the outer cover sheet 27 extend outward from the side edges of the absorber 23, and on the inner surface of the portion from this extended portion to the side portion of the top sheet 22, the outer portion 24x in the width direction WD of the gather sheet 24s forming the three-dimensional gathers 24 is attached over the entire longitudinal direction LD, constituting a side flap portion SF where the absorber 23 does not exist. These bonded portions are shown as dot patterns in FIG. 1 and can be formed by hot melt adhesive, heat seal, or ultrasonic seal. When the outer cover sheet 27 is not provided, the liquid-impermeable sheet 21 can be extended to the side flap portion SF instead of the outer cover sheet 27 to form the outer surface side of the side flap portion SF.

[0035] As the material of the gather sheet 24s, a plastic sheet or a meltblown non-woven fabric can also be used, but in terms of the feel on the skin, a non-woven fabric treated with a water-repellent agent such as silicone is preferably used.

[0036] The central portion 24c in the width direction of the gather sheet 24s extends onto the top sheet 22, and an elongated elastic member 24G is fixed to the end portion on the central side in the width direction in an extended state along the front-rear direction by a hot melt adhesive or the like. As this elongated elastic member 24G, styrene rubber, polyolefin rubber, urethane rubber, ester rubber, polyurethane, polyethylene, polystyrene, styrene butadiene, silicone, polyester, etc., which are formed in a filamentous, string-like, belt-like shape or the like, can be used as the commonly used materials.

[0037] Also, both gather sheets 24s are bonded and fixed to the inner surface of the article (the surface of the top sheet 22 and the inner surface of the outer packaging sheet 27 in the illustrated form) over the entire front-rear direction at the outer portion 24x in the width direction, and the central portion 24c in the width direction is bonded and fixed to the inner surface of the article (the surface of the top sheet 22 in the illustrated form) at both ends in the front-rear direction, and is not fixed to the inner surface of the article (the surface of the top sheet 22 in the illustrated form) between both ends in the front-rear direction. This unfixed portion is a portion that serves as a leakage prevention wall that elastically stands up with respect to the inner surface of the article (the surface of the top sheet 22 in the illustrated form), and its starting point 24b is located at the boundary between the fixed portion 24x on the outer side in the width direction and the inner portion 24c in the gather sheet 24s.

[0038] The pad-type disposable diaper 200 in this example has an upper absorber 23A located on the outermost side and a lower absorber 23B provided on the back side thereof as an absorber 23 for absorbing and holding the liquid component of excrement. The number of layers of the absorber 23 is not particularly limited, and it can be a single layer as shown in FIG. 9 or three or more layers (not shown). As the absorber 23, one formed by mixing and integrating hydrophilic short fibers such as pulp fibers and superabsorbent polymer particles can be preferably used.

[0039] As the superabsorbent polymer particles contained in the absorber 23, those used in this type of absorbent article can be used as they are. For example, when sieving (shaking for 5 minutes) using a standard sieve of 500 μm (JIS Z8801-1:2006) and then sieving (shaking for 5 minutes) the particles that fall below this sieving sieve using a standard sieve of 180 μm (JIS Z8801-1:2006), it is desirable that the proportion of particles remaining on the 500 μm standard sieve is 30% by weight or less, and the proportion of particles remaining on the 180 μm standard sieve is 60% by weight or more. When laminating a plurality of absorbers as in the case of having the upper absorber 23A and the lower absorber 23B, superabsorbent polymer particles with different particle size distributions can be used for each absorber.

[0040] Also, the superabsorbent polymer particles are not particularly limited, but those with a water absorption rate of 20 to 50 seconds and a water absorption amount of 50 to 80 g / g can be preferably used. As the superabsorbent polymer particles, there are those such as starch-based and synthetic polymer-based ones, and starch-acrylic acid (salt) graft copolymers, saponified products of starch-acrylonitrile copolymers, acrylic acid (salt) polymers, etc. can be used.

[0041] The absorber 23 can be wrapped with a packaging sheet 26 such as crepe paper that has liquid permeability and liquid retention properties, as needed, for shaping and retaining the superabsorbent polymer particles, etc., to form an integral absorbent element. When laminating a plurality of absorbers as in the case of having the upper absorber 23A and the lower absorber 23B, in addition to wrapping each absorber individually with a packaging sheet, the plurality of absorbers can also be integrally wrapped with a packaging sheet. In some cases, the packaging sheet 26 can also be omitted.

[0042] As long as at least one of the absorbers 23 extends over the crotch portion and the rear portion, the dimension in the front-rear direction and the dimension in the width direction can be appropriately determined. In a normal case, it is preferable that the absorber 23 extends from the front portion F2 to the rear portion B2. When having a two-layer absorber, the upper absorber 23A can have the same dimensions as the lower absorber 23B, but as shown in the illustrated example, it is desirable that the overall length and the overall width of the upper absorber 23A are shorter than those of the lower absorber 23B. In a normal case, the overall length of the upper absorber 23A can be about 60 to 90% of the overall length of the lower absorber 23B, and the overall width of the upper absorber 23A can be about 60 to 90% of the overall width of the lower absorber 23B.

[0043] The total basis weight (total of short fibers and superabsorbent polymer particles) of the absorber 23 can be appropriately determined. As an example, in the case of a single-layer absorber 23, the total basis weight can be about 500 to 2000 g / m 2 and in the case of a two-layer absorber 23, the total basis weight of the upper absorber 23A can be about 200 to 700 g / m 2 and the total basis weight of the lower absorber 23B can be about 200 to 700 g / m 2 and can be about that. The ratio of the superabsorbent polymer particles in the absorber 23 can be appropriately determined. As an example, in the case of a single-layer absorber 23, it can contain superabsorbent polymer particles that are 0.4 to 1.5 times (weight ratio) the short fibers, and in the case of a two-layer absorber 23, the upper absorber 23A can contain superabsorbent polymer particles that are 0.5 to 2.0 times (weight ratio) the short fibers, and the lower absorber 23B can contain superabsorbent polymer particles that are 0.2 to 1.0 times (weight ratio) the short fibers. The thickness of the absorber 23 (excluding the region having the groove described later) is not particularly limited. As an example, in the case of a single-layer absorber 23, the thickness can be about 5 to 30 mm, and in the case of a two-layer absorber 23, the thickness of the upper absorber 23A can be about 2.5 to 20 mm, and the thickness of the lower absorber 23B can be about 2.5 to 20 mm.

[0044] The shape of the entire absorber 23 can be appropriately determined, and it can be rectangular, but it preferably has a narrow constricted portion 23n in the middle in the front-rear direction LD including the crotch portion C2. When having a two-layer structure absorber, at least the larger absorber 23 (the lower absorber 23B in the illustrated example) preferably has a predetermined portion in the middle in the front-rear direction including the crotch portion C2 formed as a narrow constricted portion 23n. The minimum width W5 of this constricted portion 23n is preferably about 50 to 65% of the width W3 of the non-constricted portions located before and after the constricted portion 23n. Also, when the front end of the article is 0% and the rear end of the article is 100%, the front end of the constricted portion 23n is preferably located in the range of 10 to 25%, the rear end of the constricted portion 23n is preferably located in the range of 40 to 65%, and the portion where the minimum width W5 of the constricted portion 23n is obtained (minimum width portion) is preferably located in the range of 25 to 30%.

[0045] On the uppermost surface of the absorber 23, a groove 23D extending in the longitudinal direction LD is provided over the crotch portion C2 and the rear portion B2. This groove 23D is formed by making the basis weight of the region of the absorber 23 having the groove 23D lower than that of the other portions, and is not formed by providing a recess on the upper surface of the absorber 23 by compression processing such as embossing. For example, as shown in FIGS. 3 to 5 and FIG. 7, a slit penetrating in the thickness direction from the upper surface to the lower surface of the upper absorber 23A is provided, and no slit is provided in the lower absorber 23B. As a whole of the upper absorber 23A and the lower absorber 23B, the basis weight of the region having the groove 23D can be made lower than that of the other portions. In this case, the bottom surface of the groove 23D is formed by the upper surface of the lower absorber 23B. Also, as shown in FIG. 10, by providing a slit penetrating in the thickness direction from the upper surface of the upper absorber 23A to the lower surface of the lower absorber 23B, as a whole of the upper absorber 23A and the lower absorber 23B, the basis weight of the region having the groove 23D can be made lower than that of the other portions. In this case, the bottom surface of the groove 23D is formed by the liquid-impermeable sheet 21. Similarly, in the case of a single-layer absorber 23, as shown in FIG. 9, by providing a slit penetrating in the thickness direction from the upper surface to the lower surface of the absorber 23, the basis weight of the region of the absorber 23 having the groove 23D can be made lower than that of the other portions. Also in this case, the bottom surface of the groove 23D is formed by the liquid-impermeable sheet 21. The above examples are examples of providing slits in the absorber 23, but instead of the slits, the groove 23D can also be formed by making the accumulation amount of the aggregated short fibers and superabsorbent polymer particles lower than that of the surroundings. In this case, the bottom surface of the groove 23D is formed by the surface of the absorber 23 having the groove 23D.

[0046] The width W2 of the groove 23D can be determined as appropriate. In a normal case, it is preferably 15 to 40 mm, and particularly preferably 20 to 30 mm. The total length of the groove 23D can be determined as appropriate. In a normal case, it is preferably 0.2 to 0.75 times the total length Y1 of the absorber 23, and particularly preferably 0.35 to 0.6 times. The depth D2 of the groove 23D can be determined as appropriate. In the unfolded state of the unabsorbed, it is preferably 0.4 to 1 times the thickness 23t of the absorber 23 (the sum of the thicknesses of all absorbers 23 when there are multiple layers of absorbers 23), and particularly preferably 0.5 to 0.7 times.

[0047] Characteristically, as shown in FIG. 5 and the like, between the topsheet 22 and the uppermost surface of the absorber 23, there is provided an absorption sheet 50 having a liquid-permeable upper sheet 51 and lower sheet 52, a storage portion 55 in which superabsorbent polymer particles 53 are stored between the upper sheet 51 and the lower sheet 52, and a joining portion 54 arranged to surround the periphery of the storage portion 55. The portions of the upper sheet 51 and the lower sheet 52 located in the storage portion 55 are not joined. The number of the storage portions 55 may be one, but it is preferably arranged in a plurality with at least an interval corresponding to the joining portion 54. In this way, by distributing and holding the superabsorbent polymer particles 53 in a large number of storage portions 55, uneven distribution of the superabsorbent polymer particles 53 in the absorption sheet 50 can be prevented.

[0048] To facilitate the arrangement of the superabsorbent polymer particles 53 during manufacturing and to ensure the volume after absorption expansion, as shown in FIG. 16, at least one of the upper sheet 51 and the lower sheet 52 in the storage portion 55 may be a concave portion 50c that is recessed outside the storage portion 55 in the unfolded state. However, as shown in FIG. 6, it may not have the concave portion 50c, and it may simply be that the superabsorbent polymer particles 53 are sandwiched between the upper sheet 51 and the lower sheet 52.

[0049] The recess 50c can be formed by subjecting the target sheet to a shaping process such as embossing. Further, by this embossing process, convex portions that bulge outward are formed in portions of the target sheet that are located in the respective accommodating portions 55. For example, when the recess 50c is formed in the upper sheet 51 by embossing, the portions of the upper sheet 51 that are located in the respective accommodating portions 55 are pushed upward, and convex portions that bulge upward are formed. The depth of the recess 50c is not particularly limited, but it is preferably about 1.0 to 7.0 mm, particularly about 1.0 to 5.0 mm.

[0050] The upper sheet 51 and the lower sheet 52 are not particularly limited as long as they are liquid-permeable materials similar to the top sheet 22. Since the upper sheet 51 and the lower sheet 52 affect the absorption rate, dry nonwoven fabrics made of hydrophilic fibers, particularly natural fibers such as cotton and pulp, and among them, airlaid pulp nonwoven fabrics containing 70% by weight or more of pulp (the remaining amount in the case of less than 100% by weight can be an appropriate synthetic fiber) are one of the particularly suitable materials for the upper sheet 51 and the lower sheet 52. The method for forming the web of the nonwoven fabric is not particularly limited, but in order to prevent the separation of the superabsorbent polymer particles 53, a method with a high fiber density such as the spunbond method or the meltblown method is preferred. Also, the fineness, basis weight, and thickness of the nonwoven fabric are preferably about 2.0 to 7.0 dtex, about 18 to 50 g / m 2 and about 0.10 to 0.60 mm, respectively.

[0051] The basis weight of the superabsorbent polymer particles 53 in the absorption sheet 50 can be appropriately determined in consideration of the maximum volume of the accommodating portion 55, that is, the thickness of the accommodating portion 55 after expansion and the degree of filling of the superabsorbent polymer particles 53 in the accommodating portion 55. That is, in order to basically prevent the joint portion 54 from peeling off, the maximum volume of each accommodating portion 55 (including the volume in a state where the upper sheet 51 and the lower sheet 52 are stretched without breaking within the range where the joint portion 54 does not peel off and the accommodating portion 55 is maintained), the type and amount of the superabsorbent polymer particles 53 arranged in each accommodating portion 55 can be determined so that the volume at the time of saturated absorption of the superabsorbent polymer particles 53 contained in each accommodating portion 55 is the same or smaller. As an example, when both the upper sheet 51 and the lower sheet 52 do not have the recessed portion 50c that depresses outside the accommodating portion 55 in the unfolded state and the superabsorbent polymer particles 53 are simply sandwiched between the upper sheet 51 and the lower sheet 52, the basis weight of the superabsorbent polymer particles 53 in each accommodating portion 55 is, for example, 100 to 300 g / m 2 can be set as such.

[0052] The planar shape of the accommodating portion 55 can be appropriately determined, and can be a hexagon, a rhombus, a square, a rectangle, a circle, an ellipse, or the like. The region between adjacent accommodating portions 55 may be entirely the joint portion 54. However, since the joint portion 54 has low or no liquid permeability, the joint portion 54 is provided only at a position along the edge of the accommodating portion 55 in the region between adjacent accommodating portions 55, and the other portions may be portions where the upper sheet 51 and the lower sheet 52 are not joined. The accommodating portions 55 can be arranged by arranging those having the same planar shape and the same dimensions, or can also be arranged by combining a plurality of types of accommodating portions 55 having at least one of different shapes and dimensions (not shown).

[0053] The planar arrangement of the accommodating portions 55 (similarly, the group of superabsorbent polymer particles 53) can be determined as appropriate, but a regularly repeating planar arrangement is preferred. For example, as shown in FIG. 6 and the like, an arrangement in which the accommodating portions 55 form rows at intervals in the longitudinal direction LD, or as shown in FIG. 12, an arrangement in which rows of the accommodating portions 55 are arranged at intervals in the longitudinal direction LD and a plurality of rows are provided at a predetermined interval in the width direction WD (including a staggered arrangement as in the illustrated example and a matrix arrangement, etc.) is preferably adopted. The accommodating portions 55 can be arranged without gaps with the joining portion 54 as a boundary. In this case, examples of the arrangement of the accommodating portions 55 include a rhombic lattice as shown in FIG. 17(a), a hexagonal lattice as shown in FIG. 17(b) (these are also called staggered), a square lattice as shown in FIG. 17(c), a rectangular lattice as shown in FIG. 17(d), a parallelepiped lattice (as shown in the figure, a form in which two groups of a large number of parallel oblique columns intersect each other) as shown in FIG. 17(e), etc. (including those inclined at an angle of less than 90 degrees with respect to the expansion and contraction direction).

[0054] The dimensions of each accommodating portion 55 can be determined as appropriate. For example, the dimension 55x in the width direction WD can be about 14 to 38 mm. Also, the dimension 55y in the longitudinal direction LD can be about 15 to 200 mm. The area of each accommodating portion 55 can be about 210 to 7600 mm 2 degrees. The interval 55d (the minimum interval when it changes) between adjacent accommodating portions in the longitudinal direction can be about 5 to 30 mm. As shown in FIG. 1 5 When having a plurality of rows of accommodating portions in the width direction, as shown, the interval 55e (the minimum interval when it changes) between adjacent rows of accommodating portions in the width direction can be about 5 to 30 mm.

[0055] The joining portion 54 only needs to be joined so as not to peel off due to the expansion pressure or the like of the superabsorbent polymer particles 53. For example, it can be a welded portion where the upper sheet 51 and the lower sheet 52 are welded like ultrasonic welding or heat sealing, or it can also be an adhesive portion joined via a hot melt adhesive.

[0056] The joint part 54 is arranged so as to surround each accommodating part 55, and as long as it forms the boundary between adjacent accommodating parts 55, it can be formed in a continuous linear shape, or can also be formed in a dotted line shape (intermittent in the direction of surrounding each accommodating part 55). It is preferable that there is no highly absorbent polymer particle 53 or, even if it exists, it is less than that in the accommodating part 55 in the region between adjacent accommodating parts 55.

[0057] The dimensions of the joint part 54 can be determined as appropriate. However, if the area is large, there is a risk that the texture will become hard. Therefore, in the case of an intermittent joint part 54, it is preferable that each individual joint part 54 is small, and in the case of a continuous joint part 54, it is preferable that the width of each individual joint part 54 is narrow.

[0058] Specifically, as shown in FIGS. 5 and 7, at least one accommodating portion 55 in the absorption sheet 50 has a width narrower than the width of the groove 23D, and 80% or more (more preferably 90% or more, particularly preferably the whole as in the illustrated example) of its width is located above the groove 23D. In the unabsorbed deployed state, when the groove 23D is trisected into an upper part, a middle part, and a bottom part in the depth direction, the absorption sheet 50 is located above the upper part of the groove 23D. In this case, at the first excretion, a part of the excreted liquid permeates through the absorption sheet 50 and flows into the space between the absorption sheet 50 and the groove 23D, and is guided backward through this space. Further, in the absorption sheet 50, the superabsorbent polymer particles 53 in the accommodating portion 55 swell (absorb and hold the excreted liquid and expand) due to the excreted liquid and fill the accommodating portion 55, and as shown in FIG. 8, the accommodating portion 55 expands and its thickness increases. At this time, since the width of the accommodating portion 55 is narrower than that of the groove 23D and most of it overlaps with the groove 23D, part or all of the expanded accommodating portion 55 enters deeper into the groove 23D than before expansion. As a result, even if the portions located on both sides in the width direction WD of the groove 23D expand in the thickness direction and the depth of the groove 23D increases, since the expanded accommodating portion 55 reduces the cross-sectional area of the groove 23D, compared with the case where this is not the case, the increase in the cross-sectional area of the groove 23D during excretion after the second time, that is, the promotion of the guidance of the excreted liquid is suppressed (the first effect). Further, since the accommodating portion 55 filled with the swollen superabsorbent polymer particles 53 has a reduced liquid permeability in the thickness direction, the introduction of the excreted liquid into the groove 23D during excretion after the second time is suppressed. Therefore, also in this respect, the promotion of the guidance of the excreted liquid by the groove 23D is suppressed (the second effect). Therefore, as a result of these, it becomes possible to suppress back leakage due to excretion after the second time.

[0059] In particular, when a plurality of rows of accommodating portions that expand so as to enter the groove are provided in series with an interval in the front-rear direction, even during excretion after the second time, the excreted liquid is introduced into the groove from the portion between the accommodating portions adjacent in the front-rear direction above the groove. Therefore, it is preferable because the absorption action through the groove and the guiding action of the excreted liquid are surely maintained. Also from such a viewpoint, the above-described joint portion corresponding to the interval between the accommodating portions is preferably provided intermittently rather than being provided over the entire portion between the accommodating portions.

[0060] Further, the accommodating portion 55 expands not only toward the groove 23D side but also toward the topsheet 22 side due to the filling of the swollen superabsorbent polymer particles 53. Here, when the thickness of the accommodating portion 55 after expansion is larger than the depth of the groove 23D, as shown in FIG. 8, a raised portion is formed on the surface of the topsheet 22, and this raised portion promotes diffusion by blocking the backward movement of the excreted liquid on the surface of the topsheet 22, so that the backward movement of the excreted liquid during the second and subsequent excretions is suppressed. Therefore, also in this respect, the promotion of the induction of the excreted liquid by the groove 23D is suppressed.

[0061] As shown in FIGS. 1, 2, and 5, the absorption sheet 50 may have only the accommodating portion 55 that expands so as to enter the groove 23D. However, as shown in FIGS. 11 to 13, a row of accommodating portions 55 that are arranged in series at intervals in the longitudinal direction LD is provided with three or more rows at intervals in the width direction WD, and it is also preferable to have a row of accommodating portions 55 that expand so as to enter the groove 23D and a row of accommodating portions 55 that do not enter the groove 23D. In this way, when having the accommodating portion 55 that does not overlap with the groove 23D at all, a raised portion is formed on the surface of the topsheet 22 due to the expansion of this accommodating portion 55, and this raised portion promotes diffusion by blocking the backward movement of the excreted liquid on the surface of the topsheet 22, so that the backward movement of the excreted liquid during the second and subsequent excretions is suppressed. In the illustrated example, the row of accommodating portions 55 that expand so as to enter one groove 23D is one row, but the row of accommodating portions 55 that expand so as to enter one groove 23D may be multiple rows.

[0062] The degree of expansion of each accommodating portion 55 in the absorption sheet 50 may be substantially constant (i.e., the volume of each accommodating portion 55 and the amount of the superabsorbent polymer particles 53 accommodated therein are substantially constant). However, the thickness at the maximum expansion of the accommodating portion 55 located at the rearmost part may be made thicker than the thickness at the maximum expansion of the accommodating portion 55 located at the foremost part, or the thickness at the maximum expansion of the accommodating portion 55 that expands so as to enter the groove 23D may be made thicker than the thickness at the maximum expansion of the accommodating portion 55 that does not enter the groove 23D. The thickness at the maximum expansion can be determined by the shape and volume of the accommodating portion 55 and the amount of the superabsorbent polymer particles 53 accommodated therein. For example, when the shapes and volumes of all the accommodating portions 55 are the same, the amount of the superabsorbent polymer particles 53 accommodated in the accommodating portion 55 located at the rearmost part can be made more than the amount of the superabsorbent polymer particles 53 accommodated in the accommodating portion 55 located at the foremost part, and the thickness at the maximum expansion of the accommodating portion 55 located at the rearmost part can be made thicker than the thickness at the maximum expansion of the accommodating portion 55 located at the foremost part. Further, when a concave portion 50c that is recessed outward is formed by embossing at the site of the accommodating portion 55 in at least one of the upper sheet 51 and the lower sheet 52, as shown in FIG. 16, the depth of the concave portion 50c of the accommodating portion 55 located at the rearmost part can be made deeper than the depth of the concave portion 50c of the accommodating portion 55 located at the foremost part, and the thickness at the maximum expansion of the accommodating portion 55 located at the rearmost part can be made thicker than the thickness at the maximum expansion of the accommodating portion 55 located at the foremost part. By varying the thickness at the maximum expansion of the accommodating portion 55 in this way, the above-described first and second actions can be more effectively exhibited.

[0063] In the maximum expansion state of the accommodating portion 55 that expands so as to enter the groove 23D, it is preferable that substantially no gap is formed between the groove 23D and the absorption sheet 50. However, as shown in FIG. 8, a certain degree (for example, 25 to 250 mm 2 ) of gap 28 remains between the corner at the bottom of the groove 23D or between the bottom surface or side surface of the groove 23D and the absorption sheet 50 that has entered the groove 23D, because the guiding action of the excreted liquid backward by the groove 23D remains.

[0064] The dimensions of the accommodating portion 55 that expands to enter the groove 23D may be the same as or different from the dimensions of the accommodating portion 55 that does not enter the groove 23D. In particular, when the width 55x of the accommodating portion 55 that expands to enter the groove 23D is 0.5 to 0.7 times the width W2 of the groove 23D, it is preferable in terms of ease of entry into the groove 23D and suppression of the movement of the excreted liquid in the groove 23D. Further, if the aspect ratio of the accommodating portion 55 becomes too large, the superabsorbent polymer particles 53 tend to be unevenly distributed. Therefore, it is preferable that the dimension 55y in the front-rear direction LD of the accommodating portion 55 is 1.5 to 3.5 times the width 55x.

[0065] The shape of the accommodating portion 55 can be appropriately determined as described above. As shown in FIG. 18, when the shape is such that the width gradually increases toward the rear side, the excreted liquid that collides with the expanded accommodating portion 55 from the front will move rearward while changing its direction toward both sides in the width direction WD. Therefore, in the accommodating portion 55 located within the groove 23D, the excreted liquid that moves rearward within the groove 23D can be diffused to both sides in the width direction WD, and in the accommodating portion 55 located outside the groove 23D, the excreted liquid that moves rearward on the surface of the topsheet 22 can be diffused to both sides in the width direction WD. Thus, the rearward movement of the excreted liquid during the second and subsequent excretions, that is, back leakage, can be suppressed. Note that in the example of the accommodating portion 55 shown in FIG. 18(a), the portion where the width gradually increases toward the rear side has a linear triangular shape, and in the example of the accommodating portion 55 shown in FIG. 18(b), the portion where the width gradually increases toward the rear side has a semi-circular shape, but it is not limited thereto.

[0066] As long as the absorbent sheet 50 is disposed between the topsheet 22 and the absorber 23, it may be disposed between the topsheet 22 and the wrapper sheet 26, or may be disposed between the wrapper sheet 26 and the absorber 23. Further, when an intermediate sheet is provided, the absorbent sheet 50 may be disposed between the intermediate sheet and the absorber 23. The upper sheet 51 of the absorbent sheet 50 is preferably joined to a member in contact with its upper surface, but it may not be joined. The lower sheet 52 of the absorbent sheet 50 is preferably not joined to a member in contact with its lower surface at a position overlapping the groove 23D, but it may be joined if the absorbent sheet 50 can be positioned above the upper portion of the groove 23D. Note that the joining of the absorbent sheet 50 to a member in contact with its upper or lower surface can be performed by welding in addition to a hot melt adhesive. In the illustrated example, the upper surface of the absorbent sheet 50 is joined to the topsheet 22 in contact therewith, but since the member (wrapper sheet 26) in contact with the lower surface of the absorbent sheet 50 is along the inner surface of the groove 23D, the lower surface of the absorbent sheet 50 is not joined to the wrapper sheet 26 at a position overlapping the groove 23D. Also, as can be seen from this example, the sheet interposed between the absorbent sheet 50 and the absorber 23 may be disposed along the inner surface of the groove 23D of the absorber 23, or may be disposed flat so as not to enter the groove 23D.

[0067] The absorbent sheet 50 may be disposed so as to cover the entire length LD in the front-rear direction of the groove 23D, but it is preferably disposed so as to cover only a part of the rear side (for example, 50 to 100% when the front end of the groove 23D is 0% and the rear end is 100%) so that the introduction of excreted liquid into the groove 23D is not excessively restricted. Also, the area ratio of the accommodating portion 55 in the region where the groove 23D and the absorbent sheet 50 overlap in the unabsorbed deployed state is preferably about 10 to 30%. Further, the width 50x of the absorbent sheet 50 may be shorter than the width W2 of the groove 23D, but it is preferably longer, and in particular, both ends of the absorbent sheet 50 are preferably positioned between both side edges of the absorber 23 and the groove 23D.

[0068] <Explanation of Terms in the Specification> When the following terms are used in the specification, they have the following meanings unless otherwise specified in the specification.

[0069] · The "front - rear direction" means the direction (vertical direction) indicated by the symbol LD in the figure, the "width direction" means the direction (left - right direction) indicated by the symbol WD in the figure, and the front - rear direction and the width direction are orthogonal to each other.

[0070] · The "MD direction (machine direction or line flow direction)" and the "CD direction (lateral direction orthogonal to the MD direction)" mean the "MD direction" and the "CD direction" of the processing equipment. Either one of them is the front - rear direction, and the other is the width direction. Also, the MD direction in the product is the direction of the fiber orientation of the non - woven fabric. The fiber orientation is the direction along which the fibers of the non - woven fabric are arranged. For example, it can be discriminated by a measurement method according to the fiber orientation test method by the zero - distance tensile strength of the TAPPI standard method T481 or a simple measurement method for determining the fiber orientation direction from the ratio of the tensile strengths in the front - rear direction and the width direction. In the illustrated embodiment, like most disposable diaper products, the front - rear direction is the MD direction, and the width direction is the CD direction.

[0071] · The "front side" means the side closer to the wearer's skin when worn, and the "back side" means the side farther from the wearer's skin when worn.

[0072] · The "surface" means the side of the member closer to the wearer's skin when worn, and the "back surface" means the side farther from the wearer's skin when worn.

[0073] · The "area ratio" means the ratio of the target part occupying the unit area, and is expressed as a percentage by dividing the total area of the target part (for example, the part where the accommodation part is formed in the unabsorbed absorbent sheet) in the target area by the area of the target area. In the form where a large number of target parts are provided at intervals, it is desirable to set the target area to a size that includes three or more target parts and calculate the area ratio.

[0074] · The "elongation rate" means the value when the natural length is set to 100%. For example, an elongation rate of 200% is synonymous with an elongation magnification of 2 times.

[0075] · "Areal density" is measured as follows. After pre-drying the sample or test piece, it is left in a test chamber or apparatus under standard conditions (test location: temperature 23 ± 1°C, relative humidity 50 ± 2%) until it reaches a constant weight. Pre-drying means making the sample or test piece reach a constant weight in an environment at 100°C. For fibers with a moisture regain of 0.0%, pre-drying may not be necessary. Using a template for sample collection (100 mm × 100 mm), cut out a sample with dimensions of 100 mm × 100 mm from the test piece in a state of constant weight. Measure the weight of the sample, multiply it by 100, and calculate the weight per square meter, which is defined as the areal density.

[0076] · The "thickness" of the absorber is measured using a thickness gauge manufactured by Ozaki Seisakusho Co., Ltd. (Peacock, Dial Thickness Gauge Large Type, Model J-B (measurement range 0 to 35 mm) or Model K-4 (measurement range 0 to 50 mm)), with the sample and the thickness gauge placed horizontally.

[0077] · For "thickness" other than the above, use an automatic thickness measuring device (KES-G5 Handy Compression Measurement Program) and perform automatic measurement under the conditions of load: 0.098 N / cm 2 and pressure area: 2 cm 2

[0078] · The water absorption amount is measured according to JIS K7223-1996 "Test Method for Water Absorption of Super Absorbent Resins".

[0079] · The water absorption rate is defined as the "time to the end point" when performing JIS K7224-1996 "Test Method for Water Absorption Rate of Super Absorbent Resins" using 2 g of super absorbent polymer and 50 g of physiological saline.

[0080] · "Artificial urine" is a mixture of urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt%, and ion-exchanged water: 97.09 wt%, and is used at a temperature of 40°C unless otherwise specified.

[0081] · The "deployed state" means a state in which it is flatly deployed without shrinkage (including any shrinkage such as shrinkage by an elastic member) or slack.

[0082] · The dimensions of each part, unless otherwise specified, mean the dimensions in the deployed state rather than the natural length state.

[0083] · When there is no description about the environmental conditions in a test or measurement, the test or measurement shall be conducted in a test chamber or device under standard conditions (the test location is at a temperature of 23 ± 1°C and a relative humidity of 50 ± 2%).

Industrial Applicability

[0084] The present invention can be used regardless of the form, such as pad - type disposable diapers, tape - type disposable diapers, pants - type disposable diapers, etc., as in the above examples, and can also be used for absorbent articles other than disposable diapers, such as sanitary napkins.

Explanation of Reference Numerals

[0085] 21... liquid - impermeable sheet, 22... top sheet, 23... absorber, 23A... upper absorber, 23B... lower absorber, 23D... groove, 24... three - dimensional gather, 24s... gather sheet, 26... packaging sheet, 27... outer packaging sheet, 50... absorbent sheet, 51... upper sheet, 52... lower sheet, 53... superabsorbent polymer particles, 54... joint portion, 55... accommodating portion, 200... pad - type disposable diaper, B2... rear portion, C2... crotch portion, F2... front portion, LD... longitudinal direction, WD... width direction.

Claims

1. A crotch portion, a front portion and a rear portion extending forward and rearward of the crotch portion respectively, an absorber extending over the crotch portion and the rear portion, a liquid-permeable topsheet provided on the front side of the absorber, and having a groove extending in the front-rear direction over the crotch portion and the rear portion provided on the uppermost surface of the absorber, the area of the absorber having the groove has a lower basis weight than the portions adjacent to both sides in the width direction of the groove in the absorber, the absorber is a mixed integrated body of superabsorbent polymer particles and short fibers, in a disposable diaper, an absorption sheet is provided between the topsheet and the uppermost surface of the absorber, the absorption sheet has a liquid-permeable upper sheet and a lower sheet, a housing portion in which superabsorbent polymer particles are housed between the upper sheet and the lower sheet, and a joining portion disposed so as to surround the periphery of the housing portion, at least one of the housing portions has a width narrower than the width of the groove, and 80% or more of its width overlaps with the groove, in an undeveloped and unabsorbed state, when the groove is divided into an upper portion, a middle portion, and a bottom portion in the depth direction, the absorption sheet is located above the upper portion of the groove, an absorbent article, characterized in that.

2. the absorption sheet has a plurality of the housing portions having a width narrower than the width of the groove and 80% or more of its width located above the groove, spaced apart in the front-rear direction, The absorbent article according to claim 1.

3. the absorption sheet has three or more rows of the housing portions arranged in series with spaces in the front-rear direction and spaced apart in the width direction, a plurality of the housing portions belonging to at least one row located in the middle in the width direction of the rows have a width narrower than the width of the groove, and 80% or more of its width overlaps with the groove, and the other housing portions do not overlap with the groove, The absorbent article according to claim 2.

4. the shapes and volumes of the housing portions are all the same, the amount of the superabsorbent polymer particles housed in the housing portion located at the rearmost portion in the front-rear direction is larger than the amount of the superabsorbent polymer particles housed in the housing portion located at the foremost portion in the front-rear direction, the thickness at the maximum expansion of the housing portion located at the rearmost portion is thicker than the thickness at the maximum expansion of the housing portion located at the foremost portion, The absorbent article according to claim 2 or 3.

5. A concave portion that is recessed outward is formed by embossing on a portion of the accommodating portion in at least one of the upper sheet and the lower sheet. The depth of the concave portion of the accommodating portion located at the rearmost part is deeper than the depth of the concave portion of the accommodating portion located at the foremost part. The thickness of the accommodating portion located at the rearmost part at the time of maximum expansion is thicker than the thickness of the accommodating portion located at the foremost part at the time of maximum expansion. The absorbent article according to claim 2 or 3.

6. The width of the groove is 15 to 40 mm. The width of the accommodating portion is 0.8 to 0.95 times the width of the groove. The length of the accommodating portion in the front-rear direction is 1.5 to 3.5 times the width of the accommodating portion. The absorbent article according to any one of claims 1 to 5.

7. The accommodating portion has a shape in which the width gradually widens toward the rear side. The absorbent article according to any one of claims 1 to 6.

8. The absorbent body is composed of a lower absorbent body that is a mixed integrated body of superabsorbent polymer particles and short fibers, and an upper absorbent body that is a mixed integrated body of superabsorbent polymer particles and short fibers provided on the front side thereof. In an intermediate region in the front-rear direction including the crotch portion, a slit having a predetermined width that penetrates the upper absorbent body alone or the upper absorbent body and the lower absorbent body in the thickness direction extends in the front-rear direction. The upper absorbent body has a total basis weight of short fibers and superabsorbent polymer particles of 200 to 700 g / m ２ , and the weight ratio of the superabsorbent polymer particles to the short fibers is 50 to 200%. The absorbent article according to any one of claims 1 to 7.

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