Absorbent article

Abstract

To suppress deterioration in diffusion performance by the crushing of a slit in an absorption layer.SOLUTION: An absorber 56 from a front part F to a back part B is formed of two absorption layers 55. The absorption layer 55a having a slit 40 is provided with the slit 40 which is continuous in a front-back direction LD without branching. Two side edges 59 of the slit 40 are separated from each other in the width direction WD in the developed state. The slit 40 includes a first part 40a in which an interval d1 in the width direction WD of the two side edges 59 is minimum and a second part 40b in which an interval d2 in the width direction WD is wider than that of the first part 40a and maximum so that even when the absorber 56 is compressed in the width direction WD and the two side edges 59 of the slit 40 come in contact with each other, the gap of the slit 40 is maintained in the part other than the first part 40a.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an absorbent article provided with an absorber having a slit.

Background Art

[0002] In various disposable diapers, sanitary napkins, and other absorbent articles of a general pad type, tape type, pants type, etc., by spreading excretions such as urine more widely, it becomes possible to absorb more excretions. For example, if a slit extending in the front-rear direction is provided in the middle region in the width direction of the absorber, the excretions are guided in the front-rear direction through the slit, and the absorber can be used more widely for absorption (see, for example, Patent Documents 1 and 2).

[0003] However, since the absorbent article is sandwiched between the wearer's thighs, in a situation where the legs are closed, etc., as a result of the portion having the absorber being compressed in the width direction, a decrease in the area of the slit is inevitable. And, when both side edges of the slit of a conventional absorbent article are in a parallel straight line shape along the front-rear direction, when the portion having the absorber is compressed in the width direction, the slit partially or almost entirely disappears due to the contact of both side edges of the slit, resulting in a problem that the diffusion performance deteriorates.

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, a main problem of the present invention is to suppress a decrease in diffusion performance due to the slit being crushed, etc.

Means for Solving the Problems

[0006] The above problems are solved by the absorbent article described below. <First Aspect> A crotch portion, a front portion and a rear portion extending forward and rearward of the crotch portion, respectively, An absorber including at least one absorbent layer that extends in the front-rear direction without branching and is provided at least in the crotch portion and has a slit extending in the front-rear direction, An absorbent article comprising a liquid-permeable topsheet provided on the front side of the absorbent layer, Both side edges of the slit are spaced apart in the width direction over the entire front-rear direction in the unfolded state, The slit has a first portion where the widthwise interval between both side edges of the slit is minimum and a second portion where the widthwise interval between both side edges of the slit is wider than the first portion and maximum in the unfolded state, An absorbent article characterized by the above.

[0007] (Function and Effect) In this absorbent article, when the portion having the absorber is not compressed in the width direction or even if it is compressed, the both side edges of the slit do not contact at all, the entire front-rear direction of the slit contributes to the improvement of the diffusion performance. And even when the portion having the absorber is compressed in the width direction and the both side edges of the slit contact, the both side edges in the first portion contact first, and further compression deformation in the width direction is inhibited, so that the gap (interval between both side edges) of the slit is likely to be maintained in the portion other than the first portion (including the second portion). As a result, in this absorbent article, it is possible to suppress the deterioration of the diffusion performance due to the slit being crushed.

[0008] <Second Aspect> The slit has the first portion and the second portion alternately and repeatedly, The ratio of the front-rear dimension other than the first portion to the front-rear dimension of the slit is 50 to 80%, The absorbent article of the first aspect.

[0009] (Function and Effect) In order to achieve both the function of preventing the slit from collapsing by the first part and the diffusion performance by the parts other than the first part, it is desirable to configure as in this embodiment.

[0010] <The Third Embodiment> Both side edges of a part or all of the slit are wavy parts having an amplitude in the width direction, The wavy part of one side edge of the slit and the wavy part of the other side edge of the slit have the same waveform and are in antiphase or out of phase. The absorbent article of the first or second embodiment.

[0011] (Function and Effect) The shape of the side edge of the slit is not particularly limited as long as it has the aforementioned first part and second part. However, it is preferable to have wavy parts with the same waveform on both side edges as in this embodiment because the deformation characteristics and appearance of the absorbent article will be good.

[0012] <The Fourth Embodiment> Of both side edges of a part or all of the slit, one side edge is a wavy part having an amplitude in the width direction, and the other side edge is linear. The absorbent article of the first or second embodiment.

[0013] (Function and Effect) In the third embodiment, when the slit is compressed in the width direction with one side of the absorbent layer having the slit being displaced in the front-rear direction with respect to the other side across the slit, there is a possibility that the wavy parts may mesh and the function of preventing collapse by the first part may not be exerted. However, it is preferable to be configured as in this embodiment because such meshing does not occur.

[0014] <The Fifth Embodiment> Of both side edges of a part or all of the slit, one side edge is a first wavy part having an amplitude in the width direction, and the other side edge is a second wavy part having an amplitude smaller than that of the first wavy part. The absorbent article according to the first or second aspect.

[0015] (Function and effect) In the third aspect, when the slit in the absorbent layer having the slit is compressed in the width direction with one side on one side of the slit shifted in the front-rear direction with respect to the other side, the wavy portions may mesh and the function of preventing crushing by the first portion may not be exhibited. However, if it is configured as in this aspect, it does not mesh completely and a gap remains between the first wavy portion and the second wavy portion, which is preferable.

[0016] <The sixth aspect> The absorber has an absorbent layer having the slit and an absorbent layer not having the slit. The absorbent layer not having the slit has a length extending over the entire front-rear direction of the slit and a width extending on both sides in the width direction of the slit. The absorbent article according to any one of the first to fifth aspects.

[0017] (Function and effect) When the absorber includes only one absorbent layer having the slit, the slit is easily compressed in the width direction. However, if it has an absorbent layer having the slit and an absorbent layer not having the slit as in this aspect, the absorbent layer not having the slit resists deformation, making it difficult for the entire absorber to be compressed in the width direction. Not only is the slit less likely to be crushed, but also one side of the absorbent layer having the slit on one side of the slit is less likely to be displaced in the front-rear direction with respect to the other side, which is preferable.

[0018] <The seventh aspect> The absorbent layer not having the slit is provided directly below the absorbent layer having the slit. The absorbent layer not having the slit has grooves provided on the surface. Part or all of the grooves overlap the slit outside the first portion. The absorbent article according to the sixth aspect.

[0019] (Function and effect) As described above, when the both side edges in the first part of the slit come into contact, the inflow of excreted liquid into the slit and the diffusion of the excreted liquid in the direction along the slit are inhibited at this contact part. On the other hand, when a groove is formed on the surface of the absorbent layer directly below the absorbent layer having the slit as in this embodiment, and a part or all of the groove is configured to overlap with a part other than the first part of the slit (including the second part), even when the both side edges in the first part of the slit come into contact, the excreted liquid that has flowed into the slit in the part other than the first part can diffuse through the groove, so that a decrease in diffusibility can be suppressed as compared with the case where there is no such groove. Note that the groove and the slit overlapping means that the bottom of the groove overlaps between the both side edges of the slit.

[0020] <The eighth aspect> In a range of 60% or more in the front-rear direction of the crotch part, not having the groove The absorbent article of the seventh aspect.

[0021] (Function and effect) When a groove is provided in the absorbent layer, the absorption amount of the absorbent layer decreases. Therefore, it is desirable to limit the range where the groove is provided as in this embodiment.

[0022] <The ninth aspect> The groove extends across the front and rear both sides of the first part in the slit. The absorbent article of the seventh or eighth aspect.

[0023] (Function and effect) When the groove is arranged in this way, even when the both side edges in the first part of the slit come into contact, the groove serves as a tunnel to connect the gaps on the front and rear both sides of the first part. Therefore, a decrease in diffusibility can be suppressed as compared with the case where there is no such groove.

[0024] <The tenth aspect> The slit is continuous from the front end to the rear end of the absorbent layer having the slit. The absorbent article of any one of the first to ninth aspects.

[0025] (Function and effect) When the slit is continuous (perforating) from the front end to the rear end of the absorbent layer as in this embodiment, the slit is particularly likely to be compressed in the width direction. Therefore, each of the above-described embodiments is particularly significant when having such a slit.

Advantages of the Invention

[0026] According to the present invention, advantages such as suppressing a decrease in diffusion performance due to crushing of the slit are brought about.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out the Invention

[0028] Hereinafter, as an example of an absorbent article, an example of a pad-type disposable diaper will be described in detail with reference to the accompanying drawings. Each constituent member adjacent in the thickness direction is fixed or joined in the same manner as a known diaper as necessary, except for the fixing or joining portions described below. The dot pattern portion 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 shape, Z shape, wave shape, etc., or pattern coating (transfer of hot melt adhesive in 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 an 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 constituent member, means such as heat sealing or ultrasonic sealing by material welding can also be used. In a portion where liquid permeability in the thickness direction is required, the constituent 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 shape, Z shape, wave shape, etc. can be preferably used. When applying in a range wider than the coating width by one nozzle, intermittent pattern coating in a spiral shape, Z shape, wave shape, etc. can be performed with or without an interval in the width direction WD. As the joining means for joining each constituent member, means such as heat sealing or ultrasonic sealing by material welding can also be used.

[0029] 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 punch 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.

[0030] Figs. 1 to 5 show an example of a pad-type disposable diaper 100. This pad-type disposable diaper 100 is used by being laid on the inner surface of an outer such as a pant-type disposable diaper, etc., has a narrow width, and does not have a side flap SF extending laterally from the absorber 56. Although not shown, it may have a pair of side flaps SF without an absorber 56 that extend laterally from both side edges of the absorber 56. The pad-type disposable diaper 100 of this example has a crotch portion C, a front portion F extending forward from the crotch portion C, and a rear portion B extending rearward from the crotch portion C. Here, the crotch portion C means the range in the longitudinal direction LD having this constricted region 56N when the absorber 56 has the constricted region 56N described later, and when the absorber 56 does not have the constricted region 56N, it means the portion located at the center in the longitudinal direction LD and having a dimension in the longitudinal direction LD of 20 to 30% of the total product length Y.

[0031] The disposable diaper 100 of this pad type has a constricted area 56N with cutouts on both sides of the crotch area C, but it can also be appropriately deformed, such as having cutouts at the four corners, not having the constricted area 56N, or being a rectangle having long sides (both side edges 59) along the longitudinal direction LD.

[0032] As shown in FIGS. 1 to 5, the disposable diaper 100 of this pad type includes an absorber 56 that absorbs and holds urine, a packaging sheet 58 that wraps the absorber 56, a top sheet 30 provided on the front side of the absorber 56, a back waterproof sheet 11 provided on the back side of the absorber 56, and rising gathers 60 that rise from a starting end 61 extending along the longitudinal direction LD and are respectively provided on both sides in the width direction WD of the surface.

[0033] (Top sheet) The top sheet 30 has liquid permeability, and examples thereof include a perforated or non-perforated nonwoven fabric, a perforated plastic sheet, and the like. Also, the top sheet 30 may be composed of a single sheet or a laminated sheet obtained by laminating two or more sheets. Similarly, the top sheet 30 may be composed of a single sheet or two or more sheets in the planar direction.

[0034] In addition to extending as shown in the illustrated example so as to form a part of the rising gathers 60, both sides of the top sheet 30 may be folded back to the back side at the side edges of the absorption element 50 and passed between the back waterproof sheet 11 and the rising gathers 60 to reach the back side of the absorption element 50, or may protrude laterally from the side edges of the absorption element 50 without being folded back at the side edges of the absorption element 50 to form a part of the side flap SF.

[0035] The top sheet 30 is preferably fixed to a member adjacent to the back side by a bonding means such as heat sealing or ultrasonic sealing, or a hot melt adhesive for the purpose of preventing displacement relative to the back side member. In the illustrated example, the top sheet 30 is fixed to a portion located on the front side of the absorber 56 in the packaging sheet 58 by a hot melt adhesive applied to its back surface.

[0036] (Back waterproof sheet) The material of the back waterproof sheet 11 is not particularly limited, and examples thereof include a waterproof resin film made of a polyolefin resin such as polyethylene or polypropylene, and a non-woven fabric having waterproof properties. As the back waterproof sheet 11, it is preferable to use a material having moisture permeability from the viewpoint of preventing stuffiness. As the waterproof resin film having moisture permeability, a microporous waterproof resin film obtained by kneading an inorganic filler in a polyolefin resin such as polyethylene or polypropylene, forming a sheet, and then stretching it in a uniaxial or biaxial direction is suitable.

[0037] (Absorber) The absorber 56 (that is, each layer of the absorption layer 55 described later) can be formed by an aggregate of fibers. As this fiber aggregate, in addition to a product obtained by laminating short fibers such as cotton pulp and synthetic fibers, a filament aggregate obtained by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as needed can also be used. The fiber basis weight of the entire absorber 56, when laminating cotton pulp or short fibers, can be, for example, about 100 to 450 g / m 2 and in the case of a filament aggregate, for example, 30 to 120 g / m 2It can be set to a certain degree. In the case of synthetic fibers, the fineness is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. In the case of a filament aggregate, the filaments may be non-crimped fibers, but are preferably crimped fibers. The degree of crimp of the crimped fibers can be, for example, 5 to 75 per 2.54 cm, preferably 10 to 50, and more preferably about 15 to 50. Also, uniformly crimped crimped fibers can be used. It is preferable to disperse and hold superabsorbent polymer particles in the absorber 56.

[0038] As long as the absorber 56 continues from the front part F to the rear part B, its dimensions can be appropriately determined, but it is preferable that it extends to the peripheral part of the product or the vicinity thereof in the front-rear direction LD and the width direction WD. Note that the symbol 56X indicates the total width of the absorber 56, and the symbol 56Y indicates the total length of the absorber 56.

[0039] The absorber 56 may have a rectangular shape, but as shown in FIG. 1, it has a constricted region 56N that is located between the front part F, the rear part B and has a narrower width than the front part F and the rear part B (forming a substantially hourglass shape in plan view), which is preferable because the fit of the absorber 56 itself and the rising gathers 60 around the legs is improved. In this case, the width of the constricted region 56N (the width of the narrowest part in the absorber 56) can be appropriately determined, but can be, for example, 0.5 to 0.8 times the total width 56X of the absorber 56.

[0040] (Superabsorbent polymer particles) In the absorber 56 (i.e., each layer of the absorption layer 55 described later), highly absorbent polymer particles can be contained in part or in whole. The highly absorbent polymer particles include "powder" in addition to "particles". As the highly absorbent polymer particles, those used for this type of disposable diaper can be used as they are. For example, it is desirable that the proportion of particles remaining on the sieve in the sieving (shaking for 5 minutes) using a 500 μm standard sieve (JIS Z8801-1:2006) is 30% by weight or less, and it is also desirable that the proportion of particles remaining on the sieve in the sieving (shaking for 5 minutes) using an 180 μm standard sieve (JIS Z8801-1:2006) is 60% by weight or more.

[0041] As the material of the highly absorbent polymer particles, it can be used without particular limitation, but those with a water absorption of 40 g / g or more are preferable. As the highly absorbent polymer particles, there are those such as starch-based, cellulose-based, and synthetic polymer-based. Those such as starch-acrylic acid (salt) graft copolymer, saponified product of starch-acrylonitrile copolymer, cross-linked product of sodium carboxymethyl cellulose, and acrylic acid (salt) polymer can be used. As the shape of the highly absorbent polymer particles, usually used powdery or granular ones are preferable, but other shapes can also be used.

[0042] As the highly absorbent polymer particles, those with a water absorption rate of 70 seconds or less, particularly 40 seconds or less, are preferably used. If the water absorption rate is too slow, so-called reverse flow, in which the liquid supplied into the absorber 56 flows back outside the absorber 56, is likely to occur.

[0043] Also, as the highly absorbent polymer particles, those with a gel strength of 1000 Pa or more are preferably used. Thereby, even when the absorber 56 is bulky, the stickiness after liquid absorption can be effectively suppressed.

[0044] The basis weight of the highly absorbent polymer particles can be appropriately determined according to the absorption amount required for the use of the absorber 56. Therefore, although it cannot be generally stated, as a whole of the absorber 56, it is 50 to 350 g / m 2It can be set as such. When the basis weight of the polymer is less than 50 g / m 2 , it becomes difficult to ensure the absorption amount. When it exceeds 350 g / m 2 , the effect saturates.

[0045] The ratio of the fiber and the superabsorbent polymer particles in the absorber 56 is not particularly limited. For example, the fiber:superabsorbent polymer particles can be 40:60 to 65:35 by weight ratio.

[0046] (Packaging sheet) To ensure or enhance the shape retention of the absorber 56, it is preferable to wrap the entire absorber 56 with the packaging sheet 58, or wrap each layer of the absorption layer 55 described later with separate packaging sheets 58. The packaging sheet 58 can also be omitted. When using the packaging sheet 58, as its material, tissue paper, especially crepe paper, non-woven fabric, poly-laminated non-woven fabric, a sheet with small holes, etc. can be used. However, when the absorber 56 contains superabsorbent polymer particles, it is desirable that the sheet is one that does not allow the superabsorbent polymer particles to escape. When using a non-woven fabric instead of crepe paper, a hydrophilic SMS non-woven fabric (SMS, SSMMS, etc.) is particularly suitable, and its material can use polypropylene, polyethylene / polypropylene composite materials, etc. The basis weight is 5 - 40 g / m 2 , especially 10 - 30 g / m 2 is desirable.

[0047] The packaging form of the packaging sheet 58 can be determined as appropriate. From the viewpoints of ease of manufacturing and prevention of leakage of superabsorbent polymer particles from the front and rear edges, etc., it is preferably wound cylindrically so as to surround the front and back surfaces and both side surfaces of the absorber 56, and the front and rear edge portions thereof protrude from the front and rear of the absorber 56, and the overlapping portions of the wound overlapping portion and the front and rear protruding portions are joined by joining means such as hot melt adhesive and material welding.

[0048] (Outer non-woven fabric) In cases where it is undesirable for the back waterproof sheet 11 to be exposed on the back surface, such as when the back waterproof sheet 11 is a waterproof resin film, an outer nonwoven fabric 12 can be provided on the back surface of the product to cover the back waterproof sheet 11, as in the illustrated example. The outer nonwoven fabric 12 can also be omitted. If necessary, a joining member 8 can be provided on the outside of the outer nonwoven fabric 12, which can be fixed or joined to an outer diaper or underwear, as in known pad-type disposable diapers, but this is not necessary.

[0049] (Get up and gather) The rising gathers 60 are provided on both sides of the front surface in the width direction WD so as to rise from starting ends 61 extending in the front-to-back direction LD. The rising gathers 60 are preferably provided from the front portion F to the rear portion B, and particularly preferably extend from a position in front of the front end of the absorbent body 56 to a position in back of the rear end of the absorbent body 56.

[0050] 2 to 4 includes a main portion 66 extending from a starting end 61 extending in the front-to-back direction LD toward the center in the width direction WD, a front collapsed portion 67F formed by fixing the front end of the main portion 66 in a collapsed state, a rear collapsed portion 67B formed by fixing the rear end of the main portion 66 in a collapsed state, an unfixed risen portion 68 located between the front collapsed portion 67F and the rear collapsed portion 67B of the main portion 66, and a plurality of gathered elastic members 63 attached to the risen portion 68 at intervals in the width direction WD and extending along the front-to-back direction LD. The gathered elastic members 63 are fixed to the risen portions 68 in a stretched state along the front-to-back direction LD. As a result, the risen portions 68 contract and rise together with the gathered elastic members 63 when at their natural length, and also stretch together with the gathered elastic members 63 in response to external forces, thereby conforming to and fitting the body surface.

[0051] (Absorbent layer with slits) As shown in FIGS. 1 to 6, the absorber 56 is an absorption layer 55 extending from the front portion F to the rear portion B, and preferably includes one or more absorption layers 55a having a slit 40 that extends in the front-rear direction LD without branching and is provided at least in the crotch portion C. Although it is preferable that a plurality of absorption layers 55 are laminated, as long as the absorption layer 55a having the slit 40 is included, the absorption layer 55 may be only one layer as shown in FIGS. 12 and 13. The presence of the slit 40 at least in the crotch portion C improves the diffusibility of urine.

[0052] The thickness of the absorption layer 55 can be appropriately determined. For example, the thickness of the absorption layer 55a having the slit 40 can be, for example, 3 to 12 mm. Further, the thickness of the absorption layer 55b not having the slit 40 can be, for example, 2 to 11 mm.

[0053] When a plurality of absorption layers 55 are laminated, it is preferable to have an absorption layer 55a having a slit 40 and an absorption layer 55b not having a slit 40 because it is possible to suppress a decrease in the absorption amount due to the provision of the slit 40. In this case, the absorption layer 55a having the slit 40 may be any layer in the thickness direction. However, it is preferable that at least the uppermost layer is the absorption layer 55a having the slit 40 and includes an absorption layer 55b not having the slit 40 below it because it is easier to effectively exhibit the diffusibility of urine. Although not shown, conversely, the uppermost layer may be an absorption layer 55b not having a slit 40 and may include an absorption layer 55a having a slit 40 below it (at least one of the intermediate layer and the lowermost layer). Further, all the absorption layers 55 may have the slit 40. FIGS. 2 and 3 illustrate an absorber 56 having a two-layer structure in which the upper absorption layer 55 is an absorption layer 55a having a slit 40 and the lower absorption layer 55 is an absorption layer 55b not having a slit 40.

[0054] If both side edges 59 of the linear slit 40 in the front - rear direction LD are parallel linear along the front - rear direction LD in the crotch part C like a conventional pad - type disposable diaper, even if the both side edges 59 of the slit 40 are separated in the width direction WD over the entire front - rear direction LD in the unfolded state, when the wearer stands up or moves, and when the part having the absorber 56 is compressed in the width direction WD due to foot pressure, there is a possibility that the slit 40 may partially or almost entirely disappear due to the contact of the both side edges 59 of the slit 40. Therefore, as in the examples shown in FIGS. 1 to 6, it is preferable that the both side edges 59 of the slit 40 have a slit 40 having a first part 40a where the interval in the width direction WD between the both side edges 59 of the slit 40 is minimum and a second part 40b where the interval in the width direction WD between the both side edges 59 is maximum while being separated in the width direction WD over the entire front - rear direction LD in the unfolded state. In this pad - type disposable diaper 100, when the part having the absorber 56 is not compressed in the width direction WD or even if it is compressed and the both side edges 59 of the slit 40 do not contact at all, the entire front - rear direction LD of the slit 40 contributes to the improvement of the diffusion performance. And when the wearer closes the thighs, etc., even when the part having the absorber 56 is compressed in the width direction WD as shown in FIG. 9 and the both side edges 59 of the slit 40 contact, the both side edges 59 in the first part 40a contact first, and further compression deformation in the width direction WD is inhibited. Therefore, in the part other than the first part 40a (including the second part 40b), the gap (interval d3 between the both side edges 59) of the slit 40 is likely to be maintained. As a result, in this pad - type disposable diaper 100, it is possible to suppress the deterioration of the diffusion performance due to the slit 40 being crushed.

[0055] The slit 40 may be provided as a single one at the center in the width direction WD as shown in the illustrated example, or may be provided as a plurality of slits spaced apart in the width direction WD. Further, a plurality of slits 40 may be provided at intervals in the front-rear direction LD, and although not shown, for example, they may be provided independently in each of the crotch portion C, the front portion F, and the rear portion B. Furthermore, the slit 40 extending in the front-rear direction LD without branching may be connected in a plurality via a branching portion as in those described in Patent Document 1 and Patent Document 2. That is, the term "slit" means one that does not include a branching portion or a part. Also, the "slit extending in the front-rear direction LD" means a slit in which the angle formed by the front-rear direction LD and the center line (or a tangent line if not a straight line) of the slit 40 is 45 degrees or less, particularly 30 degrees or less. On the other hand, the slit along the front-rear direction LD means a slit in which the front-rear direction LD and the center line (or a tangent line if not a straight line) of the slit 40 are parallel (the formed angle is approximately 0 degrees).

[0056] As shown in FIGS. 1 and 5, the slit 40 only needs to be provided at least in the crotch portion C as shown in FIGS. 1 and 5, but it is preferably extended from the crotch portion C to the rear portion B, and more preferably extended from the front portion F through the crotch portion C to the rear portion B. Specifically, the length of the slit 40 in the front-rear direction LD desirably has a length of 290 mm or more, preferably 380 mm or more. The upper limit of the length of the slit 40 in the front-rear direction LD is the total length of the absorption layer 55 having the slit 40. As shown in FIG. 7 and the like, the slit 40 may be continuous from the front end to the rear end of the absorption layer 55a in which it is formed, or may be provided only in the middle in the front-rear direction LD in the absorption layer 55a as shown in FIG. 14(a), or may have a shape that is continuous to the front end in the absorption layer 55a as shown in FIG. 14(b) but not continuous to the rear end, or although not shown, may have a shape that is continuous to the rear end in the absorption layer 55a but not continuous to the front end.

[0057] The illustrated example does not have a spacer between the two side edges 59 of the slit 40 to ensure a gap, but such a spacer may be provided. Examples of such a spacer include, although not shown, an independent absorption layer provided independently in the same layer as the absorption layer 55a having the slit 40 and between the two side edges 59 of the slit 40, or a convex portion protruding from the adjacent absorption layer 55b of the absorption layer 55a having the slit 40 so as to enter between the two side edges 59 of the slit 40.

[0058] As long as the slit 40 has one or more first portions 40a and second portions 40b respectively, as shown in FIG. 7(c), the first portion 40a may be one, or as shown in FIGS. 7(a), (b), (d), (e), and (f), the first portion 40a and the second portion 40b may be alternately repeated along the direction of the slit 40. When emphasizing the diffusion performance in a state where the portion having the absorber 56 is not compressed in the width direction WD, the former is preferable, but the latter is preferable in order to achieve both the function of preventing the slit 40 from being crushed by the first portion 40a and the diffusion performance by the portion other than the first portion 40a. Further, in the latter case, it is more preferable that the ratio of the dimension in the longitudinal direction LD of the portion other than the first portion 40a to the dimension in the longitudinal direction LD of the slit 40 is 50 to 80%.

[0059] The planar shape of the two side edges 59 of the slit 40 is not particularly limited as long as it has the first portion 40a and the second portion 40b, but it is preferable that it is any one of the following (i) to (iii) because the first portion 40a and the second portion 40b are alternately repeated along the direction of the slit 40. (i) As shown in FIGS. 7(a) to (e), the two side edges 59 in at least a part of the slit 40 are wavy portions having an amplitude in the width direction WD, and the wavy portion on one side edge of the slit 40 and the wavy portion on the other side edge of the slit 40 are out of phase or have a phase shift. (ii) As shown in FIG. 7(f), one side edge is a wavy portion having an amplitude in the width direction WD, and the other side edge is a straight line along the longitudinal direction or the like. (iii) As shown in FIG. 14(c), both side edges 59 in at least a part of the slit 40 are wavy portions having an amplitude in the width direction WD, one side edge is a first wavy portion 40c having an amplitude in the width direction WD, and the other side edge is a second wavy portion 40d having an amplitude smaller than that of the first wavy portion 40c.

[0060] When providing wavy portions on the side edges of the slit 40, the shape of the wavy portions is not particularly limited, and may be a shape in which the inclination continuously changes (for example, a sine wave shape) as shown in FIG. 7(a) etc., or a rectangular wave shape in which the amplitude changes intermittently as shown in FIG. 7(e), or a triangular wave shape in which the inclination changes intermittently (not shown).

[0061] When the waveforms of the wavy portions of both side edges 59 of the slit 40 are the same, when the slit 40 is compressed in the width direction WD while the phases of the wavy portions of both side edges 59 are shifted due to the movement of the wearer, the waveforms may mesh, and the slit 40 may be blocked as shown in FIG. 8 without the function of preventing crushing by the first portion 40a. This problem is particularly likely to occur when the slit 40 is continuous from the front end to the rear end of the absorption layer 55 having the same as shown in FIGS. 7(a) and 7(e), and this problem is even more likely to occur when the absorber 56 is composed only of such an absorption layer 55 as shown in FIGS. 12 and 13. Therefore, when the waveforms of the wavy portions of both side edges 59 of the slit 40 are the same, as in the example shown in FIG. 7(f), one of the both side edges 59 of the slit 40 can be made linear and the other can be made wavy, so that they do not mesh in the first place. This shape also has the advantage that since one side of the slit 40 is linear, it does not cut the absorption layer 55, and thus the urine absorption amount can be reduced without decreasing. Further, as another example of a shape that does not mesh even when the slit 40 is displaced, as shown in FIG. 14(c), the waveforms of the wavy portions of both side edges 59 of the slit 40 are made into a first wavy portion 40c and a second wavy portion 40d having an amplitude smaller than that of the first wavy portion 40c, the amplitude in the width direction WD is changed, and the wavy portions of both side edges 59 of the slit 40 can be made into different shapes.

[0062] Also, as in the examples shown in FIGS. 1 to 6, it is also preferable to dispose an absorbent layer 55 having no slit 40 above or below the absorbent layer 55 having the slit 40, with a length extending in the longitudinal direction of the slit 40 and a width extending on both sides in the width direction WD of the slit 40. Thereby, the absorbent layer 55b having no slit 40 resists deformation and is less likely to be compressed in the width direction WD as a whole absorbent body 56. Not only is the slit 40 less likely to be crushed, but also one side of the absorbent layer 55 having the slit 40 is less likely to shift in the longitudinal direction LD with respect to the other side across the slit 40. The absorbent layer 55 having no slit 40 preferably has a dimension in the width direction WD that is larger than that of the absorbent layer 55 having the slit 40 in the range (preferably the entire length) in the longitudinal direction LD having the slit 40, and it is more preferable that both side portions protrude beyond both sides in the width direction WD of the absorbent layer 55 having the slit 40.

[0063] The interval d1 in the width direction WD of the first portion 40a can be appropriately determined, but for example, it is preferably about 5 to 20 mm, and more preferably about 10 to 15 mm. Also, the interval d2 in the width direction WD of the second portion 40b can be appropriately determined, but for example, it is preferably 1.5 to 3.0 times the interval d1 in the width direction WD of the first portion 40a, and more preferably 2.0 to 2.5 times.

[0064] When the side edges of the slit 40 are wavy, the separation distance d5 between the apexes of the convex portions adjacent in the front-back direction LD can be appropriately determined. For example, it is preferably 50 to 205 mm, and more preferably 68.5 to 102.5 mm. The separation distance d6 between the apexes of the concave portions adjacent in the front-back direction LD can also be appropriately determined. For example, it is preferably 50 to 205 mm, and more preferably 68.5 to 102.5 mm. When the side edges of the slit 40 are periodic waveforms, the separation distance (wavelength) d5 between the apexes of the convex portions adjacent in the front-back direction LD and the separation distance (wavelength) d6 between the apexes of the concave portions adjacent in the front-back direction LD are of the same length. The length (amplitude) e in the width direction WD from the apex of the convex portion to the apex of the concave portion can be appropriately determined. For example, it is preferably 5 to 30 mm, and more preferably 10 to 15 mm. In the example shown in FIG. 14(c), the length (amplitude) e1 in the width direction WD from the apex of the convex portion to the apex of the concave portion of the first wavy portion 40c can be appropriately determined. It is preferably 10 to 35 mm, and more preferably 15 to 25 mm. Also, the length (amplitude) e2 in the width direction WD from the apex of the convex portion to the apex of the concave portion of the second wavy portion 40d is preferably 1 / 1.5 to 1 / 4.0 of the length (amplitude) e1 in the width direction WD from the apex of the convex portion to the apex of the concave portion of the first wavy portion 40c, and more preferably 1 / 1.5 to 1 / 2.0 of it.

[0065] (Groove) As shown in FIGS. 1 and 6, when an absorption layer 55b without the slit 40 is provided below the absorption layer 55a having the slit 40, it is preferable to provide a groove 57 on the surface of the absorption layer 55b without the slit 40. The groove 57 may be formed by embossing the absorption layer 55, or may be formed by reducing the basis weight of a material such as fibers in a portion that becomes the groove 57 according to the shape of the mold when manufacturing the absorption layer 55. In the former case, the bottom of the groove 57 is compressed in the thickness direction and becomes denser than the portions other than the groove 57. In the latter case, the density at the bottom of the groove 57 and the other portions is substantially the same. By providing the absorption layer 55 having the groove 57 below the absorption layer 55a having the slit 40, it is possible to further enhance the diffusibility of urine while reducing the decrease in the absorption amount.

[0066] Furthermore, as shown in FIGS. 4 and 5, when a groove 57 is provided directly below the absorption layer 55a having the slit 40 and an absorption layer 55b without the slit 40 is provided, it is preferable that part or all of the groove 57 overlaps with the slit 40. As described above, when the both side edges 59 in the first part 40a of the slit 40 come into contact, the inflow of urine into the slit 40 and the diffusion of urine in the direction along the slit 40 are inhibited at this contact part. On the other hand, when the groove 57 is formed on the surface of the absorption layer 55 directly below the absorption layer 55 having the slit 40 and is configured such that part or all of it overlaps with a part other than the first part 40a of the slit 40 (including the second part 40b), even when the both side edges 59 in the first part 40a of the slit 40 come into contact, the urine that has flowed into the slit 40 in the part other than the first part 40a diffuses through the groove 57 of the lower absorption layer 55, and urine can be supplied to a wider range of the lower absorption layer 55. Therefore, it is possible to suppress a decrease in diffusibility compared to the case where such a groove 57 is not provided.

[0067] As shown in FIG. 10(a) etc., a plurality of grooves 57 may be provided at intervals in an arbitrary direction such as the front-rear direction LD or the width direction WD, or only one groove 57 may be provided as shown in FIG. 11(a). When a plurality of grooves 57 are provided, all the grooves 57 may have a portion overlapping with the slit 40 as shown in FIG. 10(a) etc., or in addition to the groove 57 overlapping with the slit 40, there may be a groove 57 that does not overlap with the slit 40 as shown in FIG. 10(c).

[0068] The degree of overlap between one groove 57 and the slit 40 can be determined as appropriate. For example, as shown in FIGS. 10(a)(b) and 11(a), when the groove 57 is provided along the center of the slit 40, the groove 57 preferably extends across both front and rear sides of the first portion 40a. More preferably, the overlapping region between one groove 57 and the slit 40 extends across a plurality of second portions 40b. In this case, the width of the groove 57 is preferably greater than 0.6 times (particularly 1 time) the interval d1 in the width direction WD between the both side edges 59 of the slit 40 in the first portion 40a, and less than the interval d2 in the width direction WD between the both side edges 59 of the slit in the second portion 40b. Also, as shown in FIGS. 10(d) and 11(b), it is also preferable that 50% or more, particularly 60% or more of the area of the groove 57 extends to a region that does not overlap with the slit 40. In this case, the area of the region where the groove 57 and the slit 40 overlap is preferably greater than half of the square of the width of the groove 57.

[0069] As illustrated in FIGS. 10 and 11, the extending direction of the groove 57 is not particularly limited. It may extend along the slit 40 (along the front-rear direction LD in the illustrated example), or may extend along an oblique direction intersecting the slit 40 as shown in FIGS. 10(d) and 11(b), or may extend in a lateral direction (not shown). In the example shown in FIG. 10, the groove 57 extends linearly, but it may be bent as shown in FIG. 11(b), or may extend in a curved shape (not shown).

[0070] Since the groove 57 itself becomes a portion with a small urine absorption amount, it is also preferable that the groove 57 is not provided in a range of 60% or more in the front-rear direction LD of the crotch portion C. Also, for the same reason, the ratio of the area of the bottom of the groove 57 in the absorbent layer 55b having the groove 57 (the sum of the areas of the bottoms of all the grooves 57 when there are a plurality of grooves 57) is preferably 0.5% to 4.0%, and more preferably 1.2% to 2.0%. The specific dimensions of the groove 57 can be determined as appropriate, but the length can be, for example, 51 to 205 mm, and more preferably 90 to 102.5 mm. Also, the width of the groove 57 can be, for example, 1 to 10 mm, and more preferably 3 to 5 mm.

[0071] The groove 57 extending in an inclined direction such as diagonally forward or diagonally backward as shown in FIGS. 10(d) and 11(b) is preferable because it is particularly excellent in diffusibility.

[0072] <Explanation of Terms in the Specification> The following terms in the specification have the following meanings unless otherwise specified in the specification.

[0073] · The "front-rear direction" means the direction indicated by the symbol LD in the figure (vertical direction), the "width direction" means the direction indicated by the symbol WD in the figure (left-right direction), and the front-rear direction and the width direction are orthogonal to each other.

[0074] · 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.

[0075] · The "surface" means the side closer to the wearer's skin when worn, and the "back surface" means the side farther from the wearer's skin when worn.

[0076] · The "areal weight" 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 a temperature of 100°C. For fibers with a moisture regain of 0.0%, pre-drying may not be necessary. From the test piece in a constant weight state, a sample template (100 mm × 100 mm) for sample collection is used to cut out a sample with dimensions of 100 mm × 100 mm. The weight of the sample is measured, multiplied by 100, and the weight per square meter is calculated as the areal weight.

[0077] · The water absorption is measured according to JIS K7223-1996 "Test Method for Water Absorption of Super Absorbent Resins".

[0078] The water absorption rate is the "time to the end point" when 2g of superabsorbent polymer and 50g of physiological saline are used and the test is carried out in accordance with JIS K7224-1996 "Test method for water absorption rate of superabsorbent polymers."

[0079] "Deployed state" means a flat, deployed state without contraction (including any contraction, such as contraction due to elastic members) or slack.

[0080] Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not in the natural length state.

[0081] If no environmental conditions are specified for a test or measurement, the test or measurement shall be carried out in a test room or device under standard conditions (temperature 23±1°C, relative humidity 50±2%). [Industrial Applicability]

[0082] The present invention is suitable for pants-type disposable diapers such as those in the above examples. [Explanation of symbols]

[0083] 11...back waterproof sheet, 30...top sheet, 40...slit, 40a...first portion, 40b...second portion, 40c...first wavy portion, 40d...second wavy portion, 55...absorbent layer, 55a...absorbent layer with slit, 55b...absorbent layer without slit, 56...absorbent body, 56N...constricted region, 57...groove, 58...packaging sheet, 59...side edges, 60...rising gathers, 61...starting end, 63...gathered elastic member, 63a...first gathered elastic member, 63b...second gathered elastic member, 63c...third gathered elastic member, 66...main portion, 67F...front collapsed portion, 67B...rear collapsed portion, 68...rising portion, B...rear portion, F...front portion, LD...front-to-back direction, C...crotch portion, WD...width direction, SF...side flaps.

Claims

1. A crotch portion, a front portion and a rear portion extending forward and backward from the front and rear sides of the crotch portion respectively, An absorber including one or more absorber layers that are absorber layers extending in the front-rear direction without branching and provided at least in the crotch portion, extending from the front portion to the rear portion and having slits, An absorbent article comprising a liquid-permeable topsheet provided on the front side of the absorber layer, Both side edges of the slit are spaced apart in the width direction over the entire front-rear direction in the deployed state, The slit has a first portion where the interval in the width direction between both side edges of the slit is minimum and a second portion where the interval in the width direction between both side edges of the slit is wider than the first portion and maximum in the deployed state, An absorbent article characterized by the above.

2. The slit has the first portion and the second portion alternately and repeatedly, The ratio of the dimension in the front-rear direction other than the first portion to the dimension in the front-rear direction of the slit is 50 to 80%, The absorbent article according to Claim 1.

3. Both side edges in part or all of the slit are wavy portions having an amplitude in the width direction, The wavy portion on one side edge of the slit and the wavy portion on the other side edge of the slit have the same waveform and are in opposite phases or have a phase shift, The absorbent article according to Claim 1 or 2.

4. Of both side edges in part or all of the slit, one side edge is a wavy portion having an amplitude in the width direction and the other side edge is linear, The absorbent article according to Claim 1 or 2.

5. Of both side edges in part or all of the slit, one side edge is a first wavy portion having an amplitude in the width direction and the other side edge is a second wavy portion having an amplitude smaller than that of the first wavy portion, The absorbent article according to Claim 1 or 2.

6. The absorber has an absorber layer having the slit and an absorber layer not having the slit, The absorber layer not having the slit has a length extending over the entire front-rear direction of the slit and a width extending on both sides in the width direction of the slit, The absorbent article according to Claim 1 or 2.

7. The absorber layer not having the slit is provided directly below the absorber layer having the slit, The absorber layer not having the slit has grooves provided on the surface, Part or all of the grooves overlap with the slit except for the first portion, The absorbent article according to Claim 6.

8. not having the groove in a range of 60% or more in the front-rear direction of the crotch portion, The absorbent article according to claim 7.

9. The groove extends across both the front and rear sides of the first portion in the slit, The absorbent article according to claim 7.

10. The slit is continuous from the front end to the rear end of the absorbent layer having the slit, The absorbent article according to claim 1.

Images