Disposable diaper

Abstract

To provide a disposable diaper which can suppress degradation of feeling of wearing on a crotch part of a wearer, and improve maintaining property of a urine reception space.SOLUTION: There is provided a disposable diaper comprising: an absorption element 50 having an absorber 56 and a packaging sheet 58 wrapping the absorber 56. The absorber 56 has a layer formed by mixing and accumulating pulp fibers and high absorbent polymer particles. The absorption element 50 has: side regions 50A, 50C which are provided near side parts relative to a first low weight part 56L and a second low weight part 56L; and a center region 50B between the first low weight part 56L and the second low weight part 56L. On the side regions 50A, 50C and the center region 50B, grooves 53 having bottom parts 51 recessed from a surface of the absorption element 50 into the absorber 56 and compressed in a thickness direction, are provided in a lattice state. The center region 50B has a reinforcement region 50R where grooves 53 deeper than the grooves 53 of the side regions 50A, 50C, are continuously provided in a lattice state.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to disposable diapers such as pad-type, tape-type, and pants-type diapers. [Background technology]

[0002] Disposable diapers generally use an absorbent body made by mixing and accumulating pulp fibers and superabsorbent polymer particles, and in order to improve the shape retention of such absorbent bodies during and after manufacturing, they are generally built in as an absorbent element wrapped in a wrapping sheet made of crepe paper or the like (see, for example, Patent Documents 1 and 2).

[0003] The absorbent element of a disposable diaper is sandwiched between the legs and is subjected to forces in various directions from both sides in the width direction due to leg movements such as walking, so it is required to have a good fit in the crotch area, while also being able to maintain its shape to prevent deformation of the absorbent body such as twisting and cracking. Of course, the absorbent element of a disposable diaper is also required to ensure absorption performance in the crotch area.

[0004] For example, when worn, the crotch area of ​​a typical disposable diaper has a base at the middle of its width and side walls that rise to form a roughly U-shaped cross section. As a result, a urine-receiving space is formed between the surface of the crotch area of ​​the disposable diaper and the skin, making it less likely to leak, even when a large amount of urine is voided at one time.

[0005] To facilitate deformation to a generally U-shaped cross-section, conventionally, low basis weight sections consisting of a pair of slits or the like penetrating the thickness direction are formed along the front-to-rear direction on both sides of the absorbent body in the width direction in the crotch region. In this case, the absorbent body is more likely to bend at the low basis weight sections, and the center region between the pair of low basis weight sections forms the bottom, while the side regions lateral to each low basis weight section rise up to form side walls. This not only facilitates the generally U-shaped cross-section of the crotch region of the diaper, but also increases the rigidity of the side walls by including the absorbent body (i.e., the urine-receiving space is less likely to collapse), providing an absorbing function. However, this function is lost or significantly reduced when the superabsorbent polymer particles expand due to urine absorption, reducing the shape retention of the absorbent body.

[0006] A known method for improving the shape retention of an absorbent body is to provide grooves with bottoms in a grid pattern or the like by compressing the absorbent element in the thickness direction by embossing or the like (see, for example, Patent Documents 1 and 2). However, since providing grooves by compression leads to improved rigidity, if compressed grooves are provided uniformly throughout the absorbent body in consideration of shape retention after absorbing urine, there is a risk that the high rigidity of the side walls, which tend to come into contact with the groin and surrounding areas, will result in a worsening wearing comfort when the crotch area is deformed into a roughly U-shaped cross section. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-000236 [Patent Document 2] Patent No. 6380454 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, a main object of the present invention is to improve the maintenance of the urine receiving space while suppressing deterioration of the wearing comfort in the crotch area. [Means for solving the problem]

[0009] The absorbent article that solves the above problems is as follows. <First aspect> The garment has a crotch portion and a front portion and a rear portion extending forward and rearward from the crotch portion, respectively; an absorbent element including an absorbent body provided in a range in the front-rear direction including the crotch area and a packaging sheet that wraps the absorbent body; The absorbent body has a layer formed by mixing and accumulating pulp fibers and highly absorbent polymer particles, At least a portion of the absorbent body located in the crotch region has a plurality of elongated low basis weight portions extending in the front-rear direction and spaced apart in the width direction, The low basis weight portion is a portion having a basis weight lower than that of the entire surrounding area, The absorbent element has a center region defined between a first low basis weight portion located closest to one side in the width direction and a second low basis weight portion located closest to the other side in the width direction, and a pair of side regions defined between the first low basis weight portion and an edge on one side of the absorbent body, and between the second low basis weight portion and an edge on the other side of the absorbent body, In the center region and the side regions, grooves are provided in a grid pattern, each groove extending from the front or back surface of the absorbent element to the absorbent body and having a bottom compressed in the thickness direction; The center region has a reinforcement region in which grooves deeper than the grooves in the side regions are arranged in a grid pattern. A disposable diaper characterized by:

[0010] (Action and effect) As will be described below, the present disposable diaper is improved in both the maintenance of the urine receiving space in the crotch area and the ability to conform to changes in shape. (a) The absorbent body is more likely to bend at the low basis weight portion, and the center region forms the bottom while the side regions rise to form side walls, which not only makes it easier for the crotch area of ​​the diaper to have an approximately U-shaped cross-section, but also makes it easier for the shape of the part corresponding to the bottom to be maintained, making it easier to maintain the urine-receiving space. (b) In both the center region and the side region, grooves are provided in a predetermined pattern that extend from at least one of the front and back surfaces of the absorbent element into the absorbent body and have bottoms that are compressed in the thickness direction. This makes it easier for the absorbent body to maintain its shape even after absorbing urine, and improves liquid diffusion in the direction along the grooves, compared to cases where this is not the case. (c) While having the advantages of (a) and (b) above, the provision of a reinforced region in the center region in which the groove depth is deeper than that in the side regions (i.e., the degree of compression at the bottom of the groove in the center region is stronger than that at the bottom of the groove in the side region, resulting in a higher density and superior shape retention), makes it possible to improve the maintenance of the urine receiving space while suppressing deterioration in the wearing comfort in the crotch area.

[0011] <Second aspect> the grooves are provided in a uniform grid pattern throughout the center region and the side regions; The depth of the groove is 60 to 90% of the maximum thickness of the absorbent element, The depth of the grooves in the reinforcement region is 1.1 to 1.6 times the depth of the grooves in the side region. A disposable diaper according to a first embodiment.

[0012] (Action and effect) The groove pattern can be determined as desired, but a uniform grid pattern across the entire center and side regions, as in this embodiment, is preferred for ease of manufacture. The groove depth (degree of compression at the bottom) can also be determined as desired, but is preferably within a range.

[0013] <Third aspect> The basis weight of the pulp fibers in the absorbent body is 100 to 450 g / m 2 and the weight ratio of the pulp fibers to the superabsorbent polymer particles in the absorbent body is 30:70 to 70:30; The maximum thickness of the absorbent element is 4 to 35 mm, The width of the bottom is 1 to 3 mm, The area ratio of the bottom of the groove to the surface of the absorbent element is 10 to 14%. A disposable diaper according to a second embodiment.

[0014] (Action and effect) The composition and dimensions of the absorbent body and the width of the bottom of the groove can be determined as appropriate, but if configured as in this embodiment, it is preferable because it not only provides the absorbent body with excellent shape retention and flexibility, but also has excellent liquid diffusion properties.

[0015] <Fourth aspect> The center region has a non-reinforced region across the entire width of the front side, the non-reinforced region having the same depth as or shallower than the grooves in the side regions. A disposable diaper according to any one of the first to third aspects.

[0016] (Action and effect) If a reinforced region is provided in front of the center region, the fit to the genitals of a male wearer may be reduced, resulting in a poor wearing comfort. Therefore, it is preferable to provide a non-reinforced region in front of the center region, as in this embodiment.

[0017] <Fifth aspect> Both side edges of the reinforcing region are located on both side edges of the center region, respectively. A disposable diaper according to any one of the first to fourth aspects.

[0018] (Action and effect) By having both side edges of the reinforcing region coincide with both side edges of the center region in this way, the absorbent body is particularly likely to bend in the low basis weight portion, which is preferable.

[0019] <Sixth aspect> The basis weight of the absorbent body in the reinforcement region is 1.1 to 1.6 times the basis weight of the absorbent body in the side region. A disposable diaper according to any one of the first to fifth aspects.

[0020] (Action and effect) To make the groove depth in the side regions shallower than that in the reinforcing regions, for example, when forming grooves by embossing using an anvil roll, the height of the protrusions on the anvil roll surface may be changed. However, changing the basis weight of the absorbent body as in this embodiment changes the thickness of the absorbent body, and this is preferable because it allows the groove depth in the reinforcing regions to be deeper than that in the side regions using a normal anvil roll with uniform protrusion height and without positioning in the MD and CD on the production line. In particular, making the maximum thickness of the absorbent elements in the center region and side regions uniform is preferable because it allows the side edges of the reinforcing regions to be aligned with the side edges of the center region using a normal anvil roll with uniform protrusion height and without positioning in the MD and CD on the production line.

[0021] <Seventh aspect> a liquid-permeable top sheet that is provided on the outer side of the absorbent body and forms a surface that comes into contact with the wearer's skin; an intermediate sheet provided between the top sheet and the absorbent body, The side edges of the intermediate sheet are located at the same position as the side edges of the center region or closer to the center in the width direction. A disposable diaper according to any one of the first to sixth aspects.

[0022] (Action and effect) By positioning the intermediate sheet in this manner, the absorbent body is more likely to bend at the low basis weight portion, which is preferable. [Effects of the Invention]

[0023] According to the present invention, it is possible to improve the maintenance of the urine receiving space while suppressing deterioration of the wearing comfort in the crotch area. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 2 is a plan view showing the inner surface of the pants-type disposable diaper in an unfolded state. [Figure 2]FIG. 2 is a plan view showing the outer surface of the pants-type disposable diaper in an unfolded state. [Figure 3] 2 is a cross-sectional view taken along line 2-2 of FIG. 1. [Figure 4] 3 is a cross-sectional view of FIG. 1 taken along line 3-3. [Figure 5] 1(a) is a cross-sectional view taken along line 4-4 in FIG. 1, and FIG. 1(b) is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 1 is a perspective view of a pants-type disposable diaper. [Figure 7] FIG. 2 is a plan view showing the outer surface of the inner body in the deployed state together with the outline of the outer body. [Figure 8] FIG. 2 is a plan view showing the surface of the absorbent body together with the outline of the wrapped nonwoven fabric. [Figure 9] FIG. 2 is an enlarged cross-sectional view showing only the main part. [Figure 10] FIG. [Figure 11] FIG. 2 is an enlarged view of a main part of the surface of the absorbent element. [Figure 12] 7 is a cross-sectional view taken along line 7-7 in FIG. [Figure 13] FIG. 3 is a cross-sectional view showing the absorbent element in a state before the absorbent body is wrapped with the wrapping nonwoven fabric. [Figure 14] FIG. 2 is a cross-sectional view showing the absorbent element in a state after the absorbent body has been wrapped with a wrapping nonwoven fabric and before the grooves have been formed. [Figure 15] 2 is a cross-sectional view of another example corresponding to the cross section 2-2 of FIG. 1. FIG. [Figure 16] 3 is a cross-sectional view of another example corresponding to the cross section 3-3 of FIG. 1. FIG. [Figure 17] FIG. 10 is a plan view showing another example of the absorbent body. [Figure 18] 1A to 1C are schematic diagrams illustrating a method for manufacturing an absorbent element. [Figure 19] FIG. 10 is an explanatory diagram of a depth measurement method. [Figure 20] 1 is a cross-sectional view schematically showing a main part of a pants-type disposable diaper in a worn state. [Figure 21] FIG. 10 is a plan view of another absorbent element. [Figure 22] FIG. 10 is a plan view of another absorbent element. DETAILED DESCRIPTION OF THE INVENTION

[0025] Below, a pants-type disposable diaper will be described in detail as an example of a disposable diaper, with reference to the accompanying drawings. Adjacent components in the thickness direction are fixed or joined as needed, in addition to the fixed or joined portions described below, in the same manner as known diapers. The dotted patterns in the cross-sectional diagram indicate adhesives such as hot melt adhesives used as the fixing or joining means. Hot melt adhesives can be applied by known methods, such as slot coating, continuous or dotted bead coating, spiral, Z-shaped, or wavy spray coating, or pattern coating (transfer of hot melt adhesive using a relief printing method). Alternatively or in addition to this, hot melt adhesive can be applied to the outer surface of the elastic member to fix the elastic member to the adjacent member. Hot melt adhesives include, for example, EVA-based, adhesive rubber-based (elastomer-based), polyolefin-based, and polyester / polyamide-based types, but no particular limitations apply. Material welding methods, such as heat sealing and ultrasonic sealing, can also be used to fix or join the components. In areas where liquid permeability in the thickness direction is required, adjacent components in the thickness direction are fixed or joined in an intermittent pattern. For example, when such intermittent fixing or joining is performed using a hot melt adhesive, intermittent pattern application such as a spiral, Z-shape, or wavy pattern can be suitably used. When applying to an area greater than the application width of a single nozzle, intermittent pattern application such as a spiral, Z-shape, or wavy pattern can be performed with or without gaps in the width direction. Material welding methods such as heat sealing and ultrasonic sealing can also be used to join the components.

[0026] Furthermore, as the nonwoven fabric in the following description, known nonwoven fabrics can be used as appropriate depending on the location and purpose. The constituent fibers of the nonwoven fabric can be selected without particular limitation, for example, synthetic fibers such as polyolefins (e.g., polyethylene or polypropylene), polyesters, and polyamides (including single-component fibers as well as core-sheath and other composite fibers), regenerated fibers (e.g., rayon or cupra), and natural fibers (e.g., cotton), and mixtures of these can also be used. To increase the flexibility of the nonwoven fabric, it is preferable to use crimped fibers as the constituent fibers. Furthermore, the constituent fibers of the nonwoven fabric can 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). Furthermore, nonwoven fabrics are generally classified into staple 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 and SMMS nonwoven fabrics in which a meltblown layer is sandwiched between spunbond layers), etc. depending on the fiber length, sheet formation method, fiber bonding method, and laminated structure, and any of these nonwoven fabrics can be used.

[0027] 1 to 6 show an example of a pants-type disposable diaper. This pants-type disposable diaper includes a rectangular front outer body 12F constituting a front waist-surrounding portion, a rectangular rear outer body 12B constituting a rear waist-surrounding portion, and an inner body 200 provided inside the outer bodies 12F and 12B so as to extend from the front outer body 12F through the crotch region M to the rear outer body 12B. Side seals 12A are formed by joining both sides of the front outer body 12F and both sides of the rear outer body 12B, and thus an opening formed by the front and rear ends of the outer bodies 12F and 12B serves as a waist opening WO through which the wearer's waist passes. The portions of the inner body 200 on both widthwise sides, surrounded by the lower edges of the outer bodies 12F and 12B and the side edges of the inner body 200, serve as leg openings LO through which the legs pass. The inner body 200 absorbs and retains excrement such as urine, and the outer bodies 12F and 12B support the inner body 200 against the wearer's body. Furthermore, the symbol Y indicates the total length of the diaper in the unfolded state when the front outer body 12F and the rear outer body 12B are not joined by the side seal 12A (the front-to-rear length from the edge of the waist opening WO of the front body F to the edge of the waist opening WO of the rear body B), and the symbol X indicates the total width of the diaper in the unfolded state.

[0028] This pants-type disposable diaper has a waist region T defined as the region between one side seal 12A and the other side seal 12A (the front-to-back range from the waist opening WO to the top of the leg openings LO), and an intermediate region L defined as the region between the edge of one leg opening LO and the edge of the other leg opening LO (between the front-to-back region having the side seal 12A of the front body F and the front-to-back region having the side seal 12A of the back body B). The portions of the front exterior body 12F and the rear exterior body 12B located in the waist region T, i.e., the front waist region and the rear waist region, can be conceptually divided into a "waist region" W that forms the edge of the waist opening, and a "lower waist region" U that is below this. Typically, when the front and rear waist regions have a boundary where the stretch stress in the width direction WD changes (e.g., where the thickness or elongation rate of the elastic member changes), the waist region W is the portion closer to the waist opening WO than the boundary closest to the waist opening WO. When no such boundary exists, the waist region W is the waist extension 12E extending further toward the waist opening WO than the absorbent body 56 or inner body 200. Their front-to-rear lengths vary depending on the product size and can be determined as appropriate. For example, the waist region W may be 15 to 40 mm, and the lower waist region U may be 65 to 120 mm. Meanwhile, both side edges of the middle region L are constricted in a U-shape or curved shape to fit around the wearer's legs, and these are the areas into which the wearer's legs are inserted. As a result, the pants-type disposable diaper in its unfolded state has a generally hourglass shape overall.

[0029] (interior body) The inner body 200 can have any shape. As an example, the inner body 200 can be a rectangle with both side edges forming the long sides, as shown in the illustration. As shown in Figures 3 to 5, the inner body 200 comprises a top sheet 30 that faces the body, a liquid-impermeable sheet 11, and an absorbent element 50 interposed between these, and is the part that performs the absorption and retention functions. Reference numeral 60 denotes rising gathers 60 that extend from both sides of the inner body 200 so as to come into contact with the wearer's legs in order to prevent excrement from leaking out the sides of the inner body 200.

[0030] (Top sheet) The top sheet 30 is liquid permeable, and examples thereof include a perforated or non-perforated nonwoven fabric and a perforated plastic sheet. The top sheet 30 may consist of a single sheet, or a laminated sheet obtained by laminating two or more sheets together. Similarly, the top sheet 30 may consist of a single sheet, or two or more sheets in the planar direction. The top sheet 30 may also be omitted.

[0031] The side edges of the top sheet 30 may be folded back to the back of the absorbent element 50 at the side edges of the absorbent element 50, or may not be folded back and may extend out to the sides of the side edges of the absorbent element 50 as in the examples shown in Figures 15 and 16. Alternatively, as in the examples shown in Figures 3 and 4, the overall width of the top sheet 30 may be made shorter than the overall width of the absorbent element 50, so that both side edges of the top sheet 30 are positioned above the absorbent element 50 and both side edges of the surface of the absorbent element 50 are exposed on the surface of the diaper.

[0032] The top sheet 30 is preferably secured to the adjacent member on the back side by a material welding joining means such as heat sealing or ultrasonic sealing, or by a hot melt adhesive, in order to prevent misalignment relative to the member on the back side. In the illustrated example, the top sheet 30 is secured to the adjacent member on the back side by a hot melt adhesive applied to its back surface.

[0033] (middle seat) As shown in the examples in Figures 15 and 16, an intermediate sheet 40 (also called a "second sheet") 40 that has a faster liquid permeability rate than the top sheet 30 can be provided to quickly transfer liquid that has passed through the top sheet 30 to the absorbent body 56. This intermediate sheet 40 is intended to quickly transfer liquid to the absorbent body 56, improving the absorption performance of the absorbent body 56 and preventing the phenomenon of absorbed liquid "backflowing" from the absorbent body 56. As shown in Figures 1 to 5, the intermediate sheet 40 can also be omitted.

[0034] Examples of the intermediate sheet 40 include the same material as the top sheet 30, spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point-bond nonwoven fabric, and crepe paper. Air-through nonwoven fabric is particularly preferred because of its bulkiness. For the air-through nonwoven fabric, it is preferable to use composite fibers with a core-sheath structure, and in this case, the resin used for the core may be polypropylene (PP), but polyester (PET) with high rigidity is preferred. The basis weight is 17 to 80 g / m 2 is preferable, and 25 to 60 g / m 2 The thickness of the raw material fibers of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use eccentric fibers, hollow fibers, or eccentric and hollow fibers as all or part of the raw material fibers.

[0035] In the illustrated example, the intermediate sheet 40 is positioned in the center and is shorter than the width of the absorbent body 56, but it may be provided across the entire width. The length of the intermediate sheet 40 in the front-to-rear direction may be the same as the entire length of the diaper, the same as the length of the absorbent element 50, or may be within a short length range centered on the liquid-receiving region.

[0036] In order to prevent the intermediate sheet 40 from shifting relative to the backside member, it is desirable to fix the intermediate sheet 40 to the backside adjacent member by a joining means that uses material welding such as heat sealing or ultrasonic sealing, or by a hot melt adhesive. In the illustrated example, the intermediate sheet 40 is fixed to the surface of the portion of the packaging sheet 58 that is located on the front side of the absorbent body 56 by a hot melt adhesive applied to the backside of the intermediate sheet 40.

[0037] (Liquid-impermeable sheet) The material of the liquid-impermeable sheet 11 is not particularly limited, but examples thereof include a plastic film made of a polyolefin resin such as polyethylene or polypropylene, a laminated nonwoven fabric in which a plastic film is provided on the surface of a nonwoven fabric, and a laminated sheet in which a nonwoven fabric or the like is overlaid and bonded to a plastic film. A liquid-impermeable and moisture-permeable material, which is preferred from the viewpoint of preventing stuffiness, is preferably used for the liquid-impermeable sheet 11. A widely used moisture-permeable plastic film is a microporous plastic film obtained by kneading an inorganic filler into a polyolefin resin such as polyethylene or polypropylene, forming the sheet, and then stretching the sheet in a uniaxial or biaxial direction. In addition, nonwoven fabrics using microdenier fibers, nonwoven fabrics whose leak-proofing properties have been enhanced by reducing the voids in the fibers through the application of heat or pressure, and sheets that have been made liquid-impermeable without using a plastic film by coating with a highly absorbent resin or a hydrophobic resin or a water-repellent agent can also be used as the liquid-impermeable sheet 11, but it is preferable to use a resin film in order to obtain sufficient adhesive strength when bonding with the cover nonwoven fabric 13 described below via a hot melt adhesive.

[0038] The liquid-impermeable sheet 11 may be wide enough to fit behind the absorbent element 50 as shown in the figure, or may be made to wrap around both sides of the absorbent element 50 and extend to both sides of the absorbent element 50 on the sides of the top sheet 30. The liquid-impermeable sheet 11 may also be omitted.

[0039] (Absorption element) The absorbent element 50 preferably includes an absorbent body 56 and a packaging sheet 58 that encases the entire absorbent body 56 .

[0040] (absorbent) The absorbent body 56 is preferably a mixture of pulp fibers and highly absorbent polymer particles. The basis weight of the pulp fibers is, for example, 100 to 450 g / m 2 It can be about.

[0041] Pulp fibers can be any fibers extracted from wood, grass, or other plants by mechanical and / or chemical processing. Pulp fibers can be made from softwood, hardwood, bamboo, rice, dregs, Japanese pampas grass, hemp, sugarcane, and other materials. Artificial cellulose fibers such as rayon and acetate can also be used. Pulp fibers can be softwood pulp fibers (pulp fibers derived from softwoods) or hardwood pulp fibers (pulp fibers derived from hardwoods), which have a shorter average fiber length than softwood pulp fibers. Either one of these fibers can be used alone, or both can be used in combination. Pulp fibers can also contain regenerated pulp fibers (recycled pulp fibers). For example, the pulp fibers can contain recycled softwood pulp fibers and recycled hardwood pulp fibers.

[0042] In an absorbent body 56 made from a mixture of softwood pulp fibers and hardwood pulp fibers, not only are fibers with a relatively long fiber length and a wide fiber width mixed in, but also fibers with a relatively short fiber length and a narrow fiber width, resulting in a higher fiber density than the conventional absorbent body 56 made solely of softwood pulp fibers. This is particularly preferable in that it not only improves the liquid retention ability of the fibers through capillary action, but also improves the retention of superabsorbent polymer particles and antibacterial granules within the absorbent body 56 (between the pulp fibers).

[0043] Both the hardwood pulp fibers and the softwood pulp fibers are preferably bleached hardwood kraft pulp (LBKP) and bleached softwood kraft pulp (NBKP) produced by the kraft process, but other types of pulp, such as soda pulp, sulfite pulp, chemi-thermomechanical pulp, chemi-reiner mechanical pulp, and thermo-chemi-mechanical pulp, may also be used.

[0044] When a mixture of softwood pulp fibers and hardwood pulp fibers is used, the content of softwood pulp fibers and hardwood pulp fibers in the total pulp fibers is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more. In particular, it is preferable that all pulp fibers in the absorbent body 56 consist essentially of softwood pulp fibers and hardwood pulp fibers. The blending amount of pulp fiber refers to the bone-dry internal amount, i.e., the mass ratio in the bone-dry state.

[0045] The term "superabsorbent polymer particles" includes not only "particles" but also "powder." The superabsorbent polymer particles used in this type of disposable diaper can be used as is. For example, when sieved using a 500 μm standard sieve (JIS Z8801-1:2006) (shaking for 5 minutes), the percentage of particles remaining on the sieve is preferably 30% by weight or less. Furthermore, when sieved using a 180 μm standard sieve (JIS Z8801-1:2006) (shaking for 5 minutes), the percentage of particles remaining on the sieve is preferably 60% by weight or more.

[0046] The material of the superabsorbent polymer particles is not particularly limited, but a water absorption capacity of 40 g / g or more is preferred. Examples of superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based materials, such as starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked products of sodium carboxymethylcellulose, and acrylic acid (salt) polymers. The shape of the superabsorbent polymer particles is preferably the commonly used powder-like form, but other shapes can also be used.

[0047] The highly absorbent polymer particles preferably have a water absorption rate of 70 seconds or less, particularly 40 seconds or less. If the water absorption rate is too slow, the liquid supplied into the absorbent body 56 tends to flow back out of the absorbent body 56, which is known as backflow.

[0048] Furthermore, the highly absorbent polymer particles preferably have a gel strength of at least 1000 Pa. This effectively prevents the sticky feeling after absorbing liquid, even when the absorbent body 56 is bulky.

[0049] The basis weight of the highly absorbent polymer particles can be determined appropriately depending on the absorption amount required for the application of the absorbent body 56. Therefore, although it cannot be generalized, it is generally in the range of 50 to 350 g / m 2 The polymer weight can be 50 g / m 2 If it is less than 350g / m, it will be difficult to ensure sufficient absorption. 2 Above this, the effect saturates.

[0050] The ratio of pulp fibers to superabsorbent polymer particles in the absorbent body 56 is not particularly limited, and can be, for example, a weight ratio of pulp fibers:superabsorbent polymer particles of 40:60 to 65:35. A weight ratio of pulp fibers:superabsorbent polymer particles of 50:50 to 65:35 is particularly preferable because it provides excellent shape retention, absorption speed, and ease of forming grooves 53 (described below) in the absorbent body 56, as well as a low risk of the superabsorbent polymer particles slipping out. It is also preferable that the superabsorbent polymer particles are distributed approximately uniformly throughout the absorbent body 56.

[0051] The maximum thickness t2 of the absorber 56 is not particularly limited, but can be, for example, 3 to 15 mm.

[0052] The absorbent body 56 may extend across both the front and rear of the crotch region M so as to include the crotch region M. In the case of a pants-type disposable diaper such as this example, it is preferable that the absorbent body 56 extends to or near the peripheral edge of the inner body 200 in both the front-to-rear direction LD and the width direction WD. The reference symbol 56X indicates the overall width of the absorbent body 56.

[0053] To ensure a sufficient absorption capacity in the crotch region M, the shape of the absorber 56 is preferably a substantially rectangular shape, as shown in the example of Fig. 8. Furthermore, to improve the fit in the crotch region M, the shape of the absorber 56 can also be a constricted shape, in which the width of the absorber 56 in the crotch region M is narrower than the front and rear sides. In this case, the width of the narrowest part of the absorber 56 in the crotch region M can be appropriately determined, for example, to be 0.85 times or more the overall width 56X of the absorber 56.

[0054] In addition, the crotch region M means the range in the front-to-back direction LD including the constricted portion 56n when the absorbent body 56 has the constricted portion 56n described below; when the absorbent body 56 does not have the constricted portion 56n but the outer shape of the diaper in the unfolded state has a constricted portion as in the illustrated example, it means the range in the front-to-back direction LD including the constricted portion of the outer shape of the diaper (in the illustrated example, between the front outer body 12F and the rear outer body 12B); when there are no constricted portions, it means the portion located in the center in the front-to-back direction LD and whose dimension in the front-to-back direction LD is 20 to 30% of the total length of the product.

[0055] (Low basis weight part) As shown in FIGS. 8 and 17 , the absorbent body 56 preferably has elongated low basis weight portions 56L extending in the front-to-rear direction LD at intervals in the width direction WD in the portion located in the crotch region M. The low basis weight portions 56L refer to portions having a lower basis weight than the entire surrounding area, and do not include portions that are compressed in the thickness direction but have no change in basis weight. The low basis weight portions 56L are preferably slits that penetrate the absorbent body 56 in the thickness direction, because this facilitates bending along the low basis weight portions 56L. However, recesses with a low accumulation of pulp fibers and superabsorbent polymer particles are also preferred, as this facilitates ensuring sufficient absorption. These recesses may be formed on either the front or back surface of the absorbent body 56. Providing such low basis weight portions 56L in the absorbent body 56 encourages bending of the absorbent body 56 along the low basis weight portions 56L, improving the fit of the absorbent element 50 in the crotch region M. The total basis weight of the pulp fibers and superabsorbent polymer particles in the low basis weight portion 56L may be less than the total basis weight of the pulp fibers and superabsorbent polymer particles in the portion other than the low basis weight portion 56L, and may be, for example, 0.1 to 0.5 times the total basis weight of the pulp fibers and superabsorbent polymer particles in the portion other than the low basis weight portion 56L. When the low basis weight portion 56L is a slit, the total basis weight of the pulp fibers and superabsorbent polymer particles is 0.

[0056] As long as the low basis weight portion 56L is elongated in the front-to-rear direction LD, it may extend linearly along the front-to-rear direction LD as shown in Fig. 17(b), or may be curved so as to be positioned laterally from the middle of the front-to-rear direction LD toward both sides of the front-to-rear direction LD as shown in the examples shown in Figs. 17(a) and 17(c). Alternatively, the front side may be a linear portion along the front-to-rear direction, and the rear side may be curved so as to be positioned laterally toward the rear as shown in the example shown in Fig. 17(d). The low basis weight portion 56L may have a bent shape with connected linear portions, or may be partially or entirely curved, such as in an arc shape. As long as portions of the low basis weight portion 56L other than the front and rear ends are away from the side edges 56e and the front and rear edges of the absorbent body 56, it is preferable that the front and rear ends of the low basis weight portion 56L are away from the side edges 56e and the front and rear edges of the absorbent body 56 as shown in Figures 17(a) and (b). However, at least one of the front and rear ends of the low basis weight portion 56L may reach the side edges 56e of the absorbent body 56 as shown in Figures 17(c) and (d). The width m1 of the low basis weight portion 56L can be determined as appropriate, and can be, for example, 0.04 to 0.1 times the width n1 of the narrowest portion of the crotch region M of the absorbent body 56 (meaning the overall width 56X in the case of a rectangle). The width m1 of the low basis weight portion 56L may be constant along its length or may vary. The dimensions and arrangement of the low basis weight portion 56L in the front-to-rear direction LD can be determined as appropriate. For example, the dimension m2 of the low basis weight portion 56L in the front-to-back direction LD can be 50 to 120%, and more preferably 50 to 80%, of the dimension of the crotch region M in the front-to-back direction LD. The low basis weight portion 56L may be contained within the crotch region M, or may extend to the front, back, or both the front and back of the crotch region M.

[0057] The low basis weight portion 56L may be provided on either side (left and right sides) of the crotch region M in the width direction WD, or may be provided in the center of the width direction WD as shown in Figure 17(a), or may be provided on either side of the width direction WD in the crotch region M, with only one on each side, as shown in Figure 17(b).

[0058] (groove) As shown in Figures 3, 4, and 9 to 11, the absorbent element 50 preferably has grooves 53 arranged in a grid pattern, each groove 53 having a bottom 51 that is recessed from the surface of the absorbent element 50 into the absorbent body 56 and compressed in the thickness direction. Although not shown, the grooves 53 may be arranged so as to recess from the back surface of the absorbent element 50 into the absorbent body 56 (in other words, the front and back of the illustrated absorbent element 50 may be reversed). By arranging the grooves 53 in a grid pattern on the surface of the absorbent element 50 in this way, it is possible to improve liquid diffusion properties and the shape retention of the absorbent body 56. The bottoms 51 of the grooves 53 are high-density portions that have been compressed by pressure (direct pressure) and have a substantially uniform thickness. Hereinafter, portions other than the bottoms 51 will be referred to as non-compressed portions 52. The uncompressed portions 52 are thicker and less dense than the bottom portion 51, but even in the uncompressed portions 52, the absorbent body 56 and the packaging sheet 58 deform near the bottom portion 51 as if pulled by the deformation of the bottom portion 51, and as a result, the density increases toward the bottom portion 51. As long as the uncompressed portions 52 are thicker and less dense than the bottom portion 51, the entire uncompressed portions 52 may be compressed in the thickness direction simultaneously with, before, or after the compression process to form the bottom portion 51. The shape and arrangement of the uncompressed portions 52 are determined according to the shape and arrangement of the bottom portion 51.

[0059] The absorbent element 50 has a center region 50B defined between the first low basis weight portion 56L located closest to one side in the width direction WD and the second low basis weight portion 56L located closest to the other side in the width direction WD, and a pair of side regions 50A, 50C defined respectively as between the first low basis weight portion 56L and one edge of the absorbent body 56 and between the second low basis weight portion 56L and the other edge of the absorbent body 56, and it is preferable that the center region 50B and the side regions 50A, 50C are provided with a grid-like groove 53 that extends from the surface of the absorbent element 50 into the absorbent body 56 and has a bottom 51 compressed in the thickness direction.

[0060] As long as the center region 50B and the side regions 50A, 50C have grooves 53 arranged in a grid pattern, regions other than the center region 50B and the side regions 50A, 50C may or may not have grooves 53 arranged in a grid pattern. Furthermore, the center region 50B, the side regions 50A, 50C, and / or some of the other regions may not have grooves 53 arranged in a grid pattern. For example, grooves 53 may not be present on both sides of the center region 50B or on the sides of the side regions 50A, 50C, but the entire absorbent element 50 may have grooves 53 arranged in a grid pattern. The grid patterns of the grooves 53 in each region may be different, but it is preferable that the grooves 53 be arranged in a uniform (single) grid pattern throughout the center region 50B and the side regions 50A, 50C, and more preferably throughout the entire absorbent element 50, as in the illustrated example.

[0061] The center region 50B preferably has a reinforcement region 50R in which grooves 53 deeper than those in the side regions 50A and 50C are connected in a grid pattern. In FIG. 9, the depth of the grooves 53 in the side regions 50A and 50C is indicated by d1, and the depth of the grooves 53 in the reinforcement region 50R is indicated by d2. In FIGS. 10, 21, and 22, the dotted portions of the grooves 53 (bottoms 51) indicate the reinforcement region 50R. The depths d1 and d2 of the grooves 53 can be determined as appropriate, for example, to be 70 to 90% of the maximum thickness of the absorbent element 50. The ratio of the depths d1 and d2 can be determined as appropriate. Generally, the depth d2 of the grooves 53 in the reinforcement region 50R is preferably 1.1 to 1.6 times, and more preferably 1.4 to 1.5 times, the depth d1 of the grooves 53 in the side regions 50A and 50C. The depth d2 of the grooves 53 in the reinforced region 50R can be determined as appropriate, but may be about 2.5 to 11 mm. The density of the bottom 51 of the grooves 53 in the side regions 50A and 50C is 120 to 210 kg / m 3 , especially 130-150 kg / m 3 On the other hand, the density of the bottom 51 of the groove 53 in the reinforced region 50R is preferably 190 to 300 kg / m 3, especially 200-220 kg / m 3 It is preferable that:

[0062] By providing the low basis weight portions 56L, the grooves 53, and the reinforced regions 50R, the maintenance and conforming deformation of the urine receiving space SP in the crotch area are improved, as will be described below. (a) As shown in Figure 20, the absorbent body 56 is easily bent at the low basis weight portion 56L, and the center region 50B forms the bottom while the side regions 50A, 50C rise to form side walls, which not only makes it easier for the crotch region M of the diaper to have an approximately U-shaped cross-section, but also makes it easier to maintain the urine receiving space SP by improving the shape retention of the part corresponding to the bottom. (b) In both the center region 50B and the side regions 50A and 50C, grooves 53 are provided in a predetermined pattern, which extend from at least one of the front and back surfaces of the absorbent element 50 into the absorbent body 56 and have bottoms 51 compressed in the thickness direction. This makes it easier for the absorbent body 56 to maintain its shape even after absorbing urine, and improves liquid diffusion in the direction along the grooves 53, compared to cases where this is not the case. (c) Furthermore, while having the advantages of (a) and (b) above, the reinforced region 50R in the center region 50B has grooves 53 that are deeper than those in the side regions 50A and 50C (i.e., the degree of compression at the bottoms 51 of the grooves 53 in the center region 50B is greater than the degree of compression at the bottoms 51 of the grooves 53 in the side regions 50A and 50C, resulting in a higher density and superior shape retention), thereby improving the maintenance of the urine receiving space SP while suppressing deterioration in the wearing comfort in the crotch area.

[0063] The reinforced region 50R may be a part of the center region 50B as shown in Figures 21 and 22, or it may be the entire center region 50B as shown in Figure 10. For example, if the reinforced region 50R is provided in the front of the center region 50B as shown in Figure 10, it may reduce the fit to the genitals of a male wearer, resulting in a poor wearing comfort. Therefore, as shown in Figure 21, the center region 50B may have a non-reinforced region 50N across the entire front side in the width direction WD that is the same depth as or shallower than the grooves 53 in the side regions 50A and 50C. Furthermore, the reinforced region 50R may be provided in regions other than the center region 50B and the side regions 50A and 50C, as long as grooves 53 deeper than the grooves 53 in the side regions 50A and 50C are continuous in a grid pattern (i.e., the reinforced region 50R is not provided in the side regions 50A and 50C). For example, the reinforcing region 50R may extend from the center region 50B to either the front or rear or both sides thereof, or may be continuous over the entire absorbent element 50 in the front-to-rear direction LD as in the example shown in FIG.

[0064] Furthermore, it is preferable that the side edges of the reinforcement region 50R coincide with the side edges of the center region 50B, respectively (i.e., located at the central edge of the first low basis weight portion 56L in the width direction WD and the central edge of the second low basis weight portion 56L in the width direction WD), as in the examples shown in Figures 10 and 21, because this makes it particularly easy for the absorbent body 56 to bend at the low basis weight portion 56L; however, as in the example shown in Figure 22, the side edges of the reinforcement region 50R may be spaced away from the side edges of the center region 50B toward the center in the width direction WD.

[0065] The absorbent element 50 having such grooves 53 can be manufactured by a known method such as embossing. For example, the absorbent element 50 having grooves 53 can be manufactured by carrying out the following steps: a first step of forming an absorbent body 56 by accumulating a mixture of pulp fibers and superabsorbent polymer particles in a predetermined mold; a second step of forming a package 50P by wrapping the entire absorbent body 56 in a package sheet 58; and a third step of passing the package 50P between an anvil roll 90 having numerous protrusions 91 arranged at intervals on its outer circumferential surface in the same pattern as the bottoms 51 of the grooves 53 and a smooth roll 92 having a cylindrical surface (without protrusions 91) facing the anvil roll 90, with the surface that will become the back surface of the absorbent element 50 facing the anvil roll 90, and pressing the portions of the package 50P that are sandwiched between the numerous protrusions 91 of the anvil roll 90 and the smooth roll 92, thereby forming grooves 53 having bottoms 51 compressed in the thickness direction. The anvil roll 90 and / or the smooth roll 92 may be pressed while being heated, or may be pressed without being heated. In the third step, only the portion of the packaging body 50P that is sandwiched between the numerous protrusions 91 of the anvil roll 90 and the smooth roll 92 may be pressed, or the entire packaging body 50P may be pressed while the portion that is sandwiched between the numerous protrusions 91 of the anvil roll 90 and the smooth roll 92 is pressed to the deepest extent.

[0066] In order to make the depth d2 of the grooves 53 in the reinforcing region 50R deeper than the depth d1 of the grooves 53 in the side regions 50A and 50C, for example, when the grooves 53 are formed by embossing using an anvil roll 90, the height of the protrusions on the surface of the anvil roll 90 may be changed. That is, the height of the protrusions of the anvil roll 90 for forming the grooves 53 in the area that will become the reinforcing region 50R may be made higher than the height of the protrusions for forming the grooves 53 in the area that will become the side regions 50A and 50C. This allows the reinforcing region 50R to be formed even if the basis weight of the absorbent body 56 is constant throughout almost the entire absorbent body 56, including the reinforcing region 50R and other areas, as shown in Figures 15 and 16. On the other hand, in the step of forming the absorbent body 56, if the basis weight of the absorbent body 56 in the reinforcing region 50R is made greater than the basis weight of the absorbent body 56 in the side regions 50A and 50C, for example, 1.1 to 1.6 times, more preferably 1.4 to 1.5 times, and the thickness t2 of the absorbent body 56 in the reinforcing region 50R is made thinner than the thickness t1 of the absorbent body 56 in the side regions 50A and 50C, this is preferable because it allows the use of a normal anvil roll 90 with uniform protrusion heights and enables the depth d2 of the grooves 53 in the reinforcing region 50R to be greater than the depth d1 of the grooves 53 in the side regions 50A and 50C without having to position the grooves in the MD and CD directions on the production line. In particular, if the maximum thickness of the absorbent elements 50 in the center region 50B and the side regions 50A, 50C are uniform, it is possible to use a normal anvil roll 90 with uniform protrusion heights and to align both side edges of the reinforcing region 50R with both side edges of the center region 50B, as in the examples shown in Figures 10 and 21, without having to position the absorbent elements 50 in the MD and CD directions on the production line. An absorbent body 56 in which the basis weight of the area that will become the reinforcing region 50R is greater than that of the other areas can be formed, for example, by making the depth of the part of the mold that forms the reinforcing region 50R deeper than that of the other areas.

[0067] When the basis weight of the absorbent body 56 in the reinforced region 50R is made greater than the basis weight of the absorbent body 56 in the side regions 50A, 50C (when the thickness t2 of the absorbent body 56 in the reinforced region 50R is made greater than the thickness t1 of the absorbent body 56 in the side regions 50A, 50C), there may be a step at the boundary between the reinforced region 50R and the side regions 50A, 50C, as in the example shown in Fig. 9, or, although not shown, there may be no step and the thickness may decrease continuously from the reinforced region 50R to the side regions 50A, 50C. When there is a step, it is preferable that the step be provided on the front side having the grooves 53, but it may also be provided on the back side or on both sides.

[0068] The thickness 50t of the absorbent element 50 and the thickness 51t of the bottom 51 of the groove 53 can be determined as appropriate. For example, the maximum value of the thickness 50t of the absorbent element 50 (the maximum value of the uncompressed portion 52) can be 4 to 35 mm, and preferably 5 to 13 mm. The thickness 51t of the bottom 51 is usually preferably 10 to 40% of the maximum value of the thickness 50t of the absorbent element 50, and more preferably 15 to 30%. The width 51w of the bottom 51 of the groove 53 can be determined as appropriate, and can be, for example, about 1 to 5 mm, and more preferably about 1 to 3 mm. The width 51w of the bottom 51 of the groove 53 is preferably approximately constant in the direction in which the groove 53 continues, but may vary.

[0069] The direction of the grooves 53 can be determined as appropriate. The grooves 53 may be arranged in a grid pattern, with the grooves 53 aligned along the front-rear direction LD repeated at intervals in the width direction WD and the grooves 53 aligned along the width direction WD repeated at intervals in the front-rear direction LD. Alternatively, one or both of the intersecting grooves 53 may be arranged diagonally. One preferred pattern of the grooves 53 is a diagonal grid pattern, as shown in FIGS. 10 and 11 , consisting of a first portion 51a extending in a direction tilted 40 to 50 degrees clockwise relative to the front-rear direction LD in a plan view and a second portion 51b extending in a direction tilted 40 to 50 degrees counterclockwise relative to the front-rear direction LD in a plan view. In this case, the shape of the unit frame 51f is generally rhombic. The dimensions of the unit frame 51f can be determined as appropriate. For example, the dimension 51x of the unit frame 51f in the width direction WD can be approximately 15 to 20 mm. The dimension 51y of the unit frame 51f in the front-rear direction LD can be approximately 15 to 20 mm.

[0070] The area ratio of the bottoms 51 of the grooves 53 to the surface of the absorbent element 50 can be determined as appropriate, but if the bottoms 51 of the grooves 53 are arranged too densely, the absorbent element 50 will become hard, so it is preferable to set it to about 5 to 20%, particularly about 10 to 14%.

[0071] The widths of the side regions 50A, 50C (maximum values, if any) can be determined as appropriate. The widths of the side regions 50A, 50C can be, for example, approximately 1 / 10 to 1 / 3 times the overall width 50W of the absorbent element 50, or approximately 5 to 50 mm, particularly approximately 10 to 30 mm. As shown in the illustrated example, in a configuration in which a top sheet 30 is provided adjacent to the surface of the absorbent element 50, both ends of the absorbent element 50 in the width direction WD are not covered by the top sheet 30, and both ends of the top sheet 30 in the width direction WD are non-bonded regions 31 that are not bonded to the surface of the absorbent element 50, and the region between these non-bonded regions 31 is bonded to the surface of the absorbent element 50 with hot melt adhesive HM4, it is preferable that the side regions 50A, 50C extend, for example, approximately 5 to 10 mm toward the center in the width direction WD. If the top sheet 30 is placed adjacent to the surface of the absorbent element 50 and the width of the top sheet 30 is made narrower than the width of the absorbent element 50 in order to reduce material costs, there is a high risk that the top sheet 30 will roll up in the non-bonded region 31 of the top sheet 30, causing the user to feel the tactile sensation of the absorbent element 50. In contrast, if the side regions 50A, 50C are at the same level as the boundary between the non-bonded region 31 and the bonded region 32 or extend further toward the center in the width direction WD than that, for example, by about 5 to 10 mm, as in the illustrated example, the entire non-bonded region 31 of the top sheet 30 will overlap with the side regions 50A, 50C, where the compression of the bottoms 51 of the grooves 53 is weaker, and even if the surface of the absorbent element 50 comes into contact with the skin, the tactile sensation felt by the wearer will be softer than that of the reinforced region 50R, which is preferable.

[0072] (packaging sheet) The packaging sheet 58 can be made of a liquid-permeable material such as tissue paper, particularly crepe paper, nonwoven fabric, polylaminated nonwoven fabric, or a perforated sheet. However, it is preferable that the sheet be one that does not allow the superabsorbent polymer particles to escape. When using nonwoven fabric instead of crepe paper, a hydrophilic nonwoven fabric having a dense layer is preferred. A particularly suitable nonwoven fabric is a laminated nonwoven fabric (including an SMS nonwoven fabric, an SSMMS nonwoven fabric, etc.) that has one or more meltblown layers and one or more protective layers such as a spunbond layer that protects the meltblown layer. The material can be polypropylene, a polyethylene / polypropylene composite, or the like.

[0073] In particular, the packaging sheet 58 has a meltblown layer formed of fibers having an average fiber diameter of 5 μm or less, and has an air permeability of 25.5 to 70.0 cm , measured in accordance with JIS L 1096:2010, in a state where five sheets are stacked, according to Method A (Fragile method). 3 / cm 2 A nonwoven fabric having a thickness of 40.0 to 70.0 cm is suitable. When five layers of this nonwoven fabric are stacked, the air permeability is 40.0 to 70.0 cm. 3 / cm 2 ·s is more preferable. This breathability can be measured, for example, using an air permeability measuring device (model AP-500KZ4) manufactured by Daiei Kagaku Seiki Seisakusho. As is well known, the meltblown layer is a nonwoven fabric layer formed by accumulating ultrafine fibers obtained by spinning a molten resin raw material into a high-velocity hot gas stream and bonding the fibers together. The constituent fibers have an average fiber diameter of 10 μm or less, long fiber lengths of 30 μm or more, and small fiber spacing. The average fiber diameter of the fibers in the meltblown layer is preferably 2.5 μm or less. The average fiber diameter of the fibers in the meltblown layer can be 1 μm or more, and is preferably 2 μm or more.

[0074] The total basis weight of the meltblown layer (if there are multiple meltblown layers, the sum of the basis weights of all layers) and the total thickness (if there are multiple meltblown layers, the sum of the thicknesses of all layers) can be determined appropriately. For example, the total basis weight of the meltblown layer is 0.3 to 6 g / m 2The total thickness of the meltblown layer can be 0.01 to 0.35 mm.

[0075] The laminated nonwoven fabric may be produced by stacking the webs that make up each layer in order, and then bonding the fibers and the layers together by thermal bonding (point bonding, hot air bonding, etc.), or by forming the nonwoven fabric layers that make up each layer individually (web formation and fiber bonding), and then stacking them and bonding the layers together thermally or with an adhesive.

[0076] A spunbond layer can be suitably used as the protective layer. As is well known, a spunbond layer is a nonwoven fabric layer formed by accumulating filaments obtained by extruding (spinning) a molten resin raw material from a nozzle and bonding the fibers together. The average fiber diameter of the constituent fibers is larger than that of the fibers in the meltblown layer, and the fiber length is also longer than that of the meltblown layer.

[0077] The fiber diameter, total basis weight (sum of basis weights of all layers when there are multiple protective layers), and total thickness (sum of thicknesses of all layers when there are multiple protective layers) of the constituent fibers of the protective layer can be appropriately determined. For example, the constituent fibers of the protective layer preferably have an average fiber diameter of 10 to 25 μm (particularly 15 to 20 μm). The total basis weight of the protective layer is preferably 5 to 17.5 g / m. 2 (Especially 5-10g / m 2 ), and the total thickness of the protective layer is preferably 0.01 to 0.35 mm (particularly 0.1 to 0.2 mm).

[0078] The basis weight and thickness of the packaging sheet 58 can be determined as appropriate. For example, when the packaging sheet 58 is a laminated nonwoven fabric, the basis weight of the packaging sheet 58 is 10 to 17 g / m 2 The thickness of the packaging sheet 58 is preferably 0.2 to 0.8 mm.

[0079] If the packaging sheet 58 is not stretchable, not only will it be difficult to form firm grooves 53, but the flexibility of the absorbent element 50 will also decrease. Therefore, it is preferable that the packaging sheet 58 has a standard elongation rate, as specified in JIS L 1913:2010, in the front-to-rear direction LD of 20 to 100%, particularly 30 to 60%, and a standard elongation rate, as specified in JIS L 1913:2010, in the width direction WD of 20 to 110%, particularly 50 to 70%.

[0080] The packaging structure of the packaging sheet 58 can be determined as appropriate, but from the standpoint of ease of manufacturing and preventing leakage of superabsorbent polymer particles from the front and rear edges, it is preferable to wrap the sheet around the absorbent body 56 in a cylindrical shape so as to surround the front, back, and both side surfaces, as shown in the illustrated example, with the front and rear edges extending beyond the front and rear of the absorbent body 56, and to join the overlapping wound portions and the overlapping portions of the extending front and rear edges by a joining means such as a hot melt adhesive or material welding.

[0081] More specifically, the packaging sheet 58 in the illustrated example has a surface portion 58s located on the front side of the absorbent body 56, a first back side portion 58a that continues from the surface portion 58s, wraps around one side edge of the absorbent body 56 to reach the back side of the absorbent body 56, and a second back side portion 58b that continues from the surface portion 58s, wraps around the other side edge of the absorbent body 56 to reach the back side of the absorbent body 56, and the first back side portion 58a and the second back side portion 58b have a laminated portion 58W in which they overlap each other, and in this laminated portion 58W the first back side portion 58a and the second back side portion 58b are bonded together by a first hot melt adhesive HM1, and in the area where the packaging sheet 58 and the absorbent body 56 face each other, the inner surface of the packaging sheet 58 and the outer surface of the absorbent body 56 are bonded together by a second hot melt adhesive HM2 and a third hot melt adhesive HM3. The wrapping nonwoven fabric may be wrapped upside down from the illustrated example, with the laminated portion 58W positioned on the front side of the absorbent element 50. The application patterns of the first hot melt adhesive HM1, the second hot melt adhesive HM2, and the third hot melt adhesive HM3 are not particularly limited, but from the viewpoint of liquid permeability, intermittent application in a spiral, Z-shape, wave-like pattern, or the like is preferably used.

[0082] 9, in the side regions 50A, 50C, it is preferable that the third hot melt adhesive HM3, which bonds at least the lower surface of the packaging sheet 58 and the upper surface of the absorbent body 56, be slot-coated (applied in a continuous film), and that the second hot melt adhesive HM2, which bonds the remaining portions, be intermittently applied. In particular, as shown in the example, it is preferable that the third hot melt adhesive HM3 be slot-coated in a region of the inner surface of the packaging sheet 58 that extends from the back side of the absorbent body 56, around the sides of the absorbent body 56, and continue to the front side of the absorbent body 56 in the side regions 50A, 50C, and then wrapped around the absorbent body 56. The third hot melt adhesive HM3 is preferably provided over the entire width direction WD of the side regions 50A, 50C, but may be provided only on the sides of the side regions 50A, 50C. Furthermore, the dimension of the third hot melt adhesive HM3 in the width direction WD may be different between the front side and the back side of the absorbent body 56, and in this case, it is preferable that the front side of the absorbent body 56 is wider.

[0083] Such a structure can be produced by, as shown in Figure 13, applying the second hot melt adhesive HM2 to the widthwise middle of the surface of the unfolded packaging sheet 58 facing the absorbent 56, applying the third hot melt adhesive HM3 adjacent to both widthwise sides of that, applying the first hot melt adhesive HM1 to one widthwise end, and then arranging the absorbent 56 so that it extends from the widthwise middle of one of the third hot melt adhesives on the packaging sheet 58 to the widthwise middle of the other third hot melt adhesive, and then applying the second hot melt adhesive HM2 over almost the entire opposite surface of the absorbent 56, and then, as shown in Figure 14, folding back the portions of the packaging sheet 58 that extend on both sides of the absorbent 56 onto the opposite surface of the absorbent 56, so that the outer surface of the absorbent 56 and the inner surface of the packaging sheet 58 are bonded together with the second hot melt adhesive HM2 and the overlapping portions of the packaging sheet 58 are bonded together with the first hot melt adhesive HM1, and then forming grooves 53 by embossing, as shown in Figure 9, etc.

[0084] When an intermediate sheet 40 is provided as in the example shown in Figures 15 and 16, it is preferable that the side edges of the intermediate sheet 40 are positioned at the same position as the side edges of the center region 50B or closer to the center in the width direction WD, as also shown in Figure 10, because this makes it easier for the absorbent body 56 to bend at the low basis weight portion 56L.

[0085] (Get up and gather) The rising gathers 60 have rising portions 68 that rise from the sides of the inner body 200, and these rising portions 68 come into contact with the area from the wearer's groin through the legs to the buttocks to prevent side leakage. In the illustrated example, the rising gathers 60 have a base side portion 60B that rises obliquely toward the center in the width direction, and a portion 60A from the middle portion to the tip side that rises obliquely toward the outside in the width direction, but this is not limited to this and appropriate modifications are possible, such as ones that rise toward the center in the width direction as a whole. The rising gathers 60 can also be omitted.

[0086] More specifically, the rising gathers 60 in the illustrated example are formed by folding a strip-shaped gathered sheet 62, having a length equal to the longitudinal length of the inner body 200, in two by folding back the leading end in the width direction WD, and by fixing a plurality of elongated gathered elastic members 63 between the folded-back portion and the sheet in the vicinity thereof in a stretched state along the longitudinal direction at intervals in the width direction WD. A base end portion of the rising gathers 60 opposite the leading end (the end portion opposite the folded-back portion of the sheet in the width direction WD) serves as a root portion 65 fixed to the side portion of the inner body 200, and the portion other than the root portion 65 serves as a main body portion 66 (the portion on the folded-back portion side) extending from the root portion 65. The main body portion 66 further has a root portion 60B extending toward the center in the width direction and a tip portion 60A folded back at the leading end of the root portion 60B and extending outward in the width direction. The front-to-rear end portions of the main body portion 66 are formed as fallen portions 67 which are fixed in a fallen state to the side surfaces of the top sheet 30, while the front-to-rear intermediate portion between them is formed as an unfixed raised portion 68, and a gathered elastic member 63 extending along the front-to-rear direction LD is fixed in a stretched state to at least the tip portion of this raised portion 68.

[0087] In the rising gathers 60 configured as described above, the contractile force of the gather elastic member 63 causes the rising portions 68 to rise up so as to come into contact with the skin as shown by the arrows in Fig. 3. In particular, when the base portion 65 is located on the back side of the inner body 200, the rising portions 68 rise up so as to open outward in the width direction in the crotch region M and its vicinity, so that the rising gathers 60 come into contact with the surrounding legs with a surface thereof, improving fit. The base portion 65 can also be fixed to the front side of the inner body 200, for example, to the surfaces of both side portions of the top sheet 30.

[0088] In a bent structure such as the illustrated example of the rising gathers 60, in which the main body portion 66 is composed of a base portion 60B extending toward the center in the width direction and a tip portion 60A folded back at the tip of the base portion 60B and extending outward in the width direction, the tip portion 60A and the base portion 60B are joined in a folded state at the fallen portion 67, and the base portion 60B is joined in a folded state to the topsheet 30. To join the opposing surfaces at the fallen portion 67, at least one of various application methods of hot melt adhesive and material welding means such as heat sealing and ultrasonic sealing can be used. In this case, the joining of the base portion 60B and the topsheet 30 and the joining of the tip portion 60A and the base portion 60B may be performed by the same means or by different means. For example, it is preferable to join the root side portion 60B and the top sheet 30 with a hot melt adhesive, and to join the tip side portion 60A and the root side portion 60B with material welding.

[0089] As the gathered sheet 62, a nonwoven fabric that is soft and has excellent uniformity and hiding power, such as a spunbond nonwoven fabric (SS, SSS, etc.), an SMS nonwoven fabric (SMS, SSMMS, etc.), or a meltblown nonwoven fabric, and that has been subjected to a water-repellent treatment with silicone or the like as necessary, can be suitably used. In this case, the fiber weight of the nonwoven fabric is 10 to 30 g / m 2 Although not shown, a waterproof film can be interposed between the two folded gathered sheets 62.

[0090] The gathered elastic members 63 can be made of rubber thread or the like. When spandex rubber thread is used, the thickness is preferably 470 to 1240 dtex, more preferably 620 to 940 dtex. The elongation percentage of the gathered elastic members 63 in the attached state is preferably 150 to 350%, more preferably 200 to 300%. The number of gathered elastic members 63 is preferably 2 to 6, more preferably 3 to 5. The appropriate spacing between the gathered elastic members 63 is 3 to 10 mm. With this configuration, the gathered elastic members 63 can easily contact the skin over their entire surface within the range where they are arranged. The gathered elastic members 63 may be arranged not only on the tip side but also on the base side.

[0091] In the rising portion 68 of the rising gathers 60, at least one of various application methods of hot melt adhesive and material welding, such as heat sealing or ultrasonic sealing, can be used to bond the inner and outer layers of the gathered sheet 62 together and to secure the gathered elastic member 63 sandwiched therebetween. Since bonding the entire inner and outer layers of the gathered sheet 62 together reduces flexibility, it is preferable to leave the areas other than the adhesive portion of the gathered elastic member 63 unbonded or to only weakly bond them. In the illustrated example, hot melt adhesive is applied only to the outer peripheral surface of the gathered elastic member 63 using an application means such as a comb gun or a SureWrap nozzle, and the gathered elastic member 63 is sandwiched between the inner and outer layers of the gathered sheet 62. This results in a structure in which the gathered elastic member 63 is secured to the inner and outer layers of the gathered sheet 62 and the inner and outer layers of the gathered sheet 62 are secured together solely by the hot melt adhesive applied to the outer peripheral surface of the gathered elastic member 63.

[0092] Similarly, the fallen portion 67 can be fixed by at least one of various application methods of hot melt adhesive and material welding such as heat sealing or ultrasonic sealing.

[0093] (Side flap) 1 to 4, etc., side flaps 70 extending out to the sides of the absorbent body 56 are provided on both sides of the inner body 200, and it is preferable that side stretchable regions SG that stretch in the front-to-rear direction are formed in these side flaps 70. The side flaps 70 in the illustrated example have one or more elongated side elastic members 73 arranged along the front-to-rear direction LD and spaced apart from one another, a first sheet layer 71 facing the outside of the side elastic member 73, and a second sheet layer 72 facing the inside of the side elastic member 73.

[0094] The sheet material forming the first sheet layer 71 and the second sheet layer 72 is not particularly limited, and any suitable nonwoven fabric can be selected, such as the nonwoven fabric that can be used for the above-mentioned rising gathers 60 and the above-mentioned outer bodies 12F, 12B. In the illustrated example, the first sheet layer 71 and the second sheet layer 72 are formed by extending the gathered sheet 62 of the rising gathers 60, as will be described later. In this case, the front and rear ends of the side flaps 70 coincide with the front and rear ends of the rising gathers 60 (i.e., the front and rear ends of the inner body 200 in this case).

[0095] The side elastic members 73 are not particularly limited, and can be elongated elastic members similar to the gathered elastic members 63 described above. The extension percentage of the side elastic members 73 in the attached state is preferably 150 to 350%, more preferably 200 to 270%. The number of side elastic members 73 is preferably 2 to 16, more preferably 6 to 10. The appropriate spacing between the side elastic members 73 is 5 to 10 mm.

[0096] The side elastic members 73 are fixed to the first sheet layer 71 and the second sheet layer 72. Various application methods of hot melt adhesive HM or material welding methods such as heat sealing and ultrasonic sealing can be used to bond the first sheet layer 71 and the second sheet layer 72 together and to secure the side elastic members 73 sandwiched between them. Because a large bonded area between the first sheet layer 71 and the second sheet layer 72 reduces flexibility, it is preferable to leave the portions of the side elastic members 73 unbonded or to only weakly bond them. In the illustrated example, the hot melt adhesive HM is applied only to the outer peripheral surfaces of the side elastic members 73 using an application method such as a comb gun or a SureWrap nozzle, and then the side elastic members 73 are sandwiched between the first sheet layer 71 and the second sheet layer 72. The hot melt adhesive HM applied only to the outer peripheral surfaces of the side elastic members 73 secures the side elastic members 73 to the first sheet layer 71 and the second sheet layer 72 and secures the first sheet layer 71 and the second sheet layer 72 together.

[0097] In the illustrated example, the sheet material constituting the first sheet layer 71 and the sheet material constituting the second sheet layer 72 are folded back at the side edges of the side flaps 70, and these folded back portions are fixed (the bag is closed) to the back surface of the liquid-impermeable sheet 11. This fixing can be performed with a hot melt adhesive HM as in the illustrated example, or by welding the materials.

[0098] The side flaps 70 may be omitted.

[0099] (exterior body) As shown in the figure, the exterior bodies 12F, 12B are composed of a rectangular front exterior body 12F that constitutes at least the waistline of the front body F, and a rectangular back exterior body 12B that constitutes at least the waistline of the back body B. The front exterior body 12F and the rear exterior body 12B may not be continuous at the crotch side and may be spaced apart in the front-to-back direction LD (two-piece exterior type), or may be continuous from the front body F to the back body B (one-piece exterior type), although this is not shown. In the two-piece exterior type, the separation distance 12d in the front-to-back direction LD can be, for example, approximately 40 to 60% of the total length Y. In the figure, the lower edges of the front exterior body 12F and the rear exterior body 12B are linear and extend along the width direction WD, but the lower edge of at least one of the front exterior body 12F and the rear exterior body 12B may be curved to fit around the legs.

[0100] In a two-piece outer-casing pants-type disposable diaper, the inner body 200 is exposed between the front outer body 12F and the rear outer body 12B. Therefore, to prevent the liquid-impermeable sheet 11 from being exposed on the back surface of the inner body 200, a cover nonwoven fabric 13 is preferably provided on the back surface of the inner body 200, extending from between the front outer body 12F and the inner body 200 to between the rear outer body 12B and the inner body 200. The inner and outer surfaces of the cover nonwoven fabric 13 can be bonded to their respective opposing surfaces with a hot-melt adhesive. The nonwoven fabric used for the cover nonwoven fabric 13 can be selected appropriately from a material similar to that of the outer bodies 12F and 12B. Although not shown, the outer body may be continuous from the front body F to the back body B, passing through the crotch area. In this case, the outer body will have not only a portion corresponding to the waist region T but also a portion corresponding to the middle region L.

[0101] The front exterior body 12F and the rear exterior body 12B have a front waist portion and a rear waist portion that form the waist region T. In the example shown in Figures 1 and 2, the front exterior body 12F and the rear exterior body 12B have the same dimensions in the front-to-rear direction LD, and the front exterior body 12F and the rear exterior body 12B do not have a portion corresponding to the middle region L, but as shown in Figure 7, the rear exterior body 12B may have a longer dimension in the front-to-rear direction than the front exterior body 12F, and the front exterior body 12F does not have a portion corresponding to the middle region L, but the rear exterior body 12B may have a buttocks cover portion C extending from the waist region T toward the middle region L. Although not shown, the front exterior body 12F may also be provided with a groin cover portion extending from the waist region T toward the middle region L.

[0102] As shown in Figures 4 and 5, the exterior bodies 12F, 12B are formed by joining an outer sheet layer and an inner sheet layer adjacent to the outer and inner sides of the elastic members 16-19 (described later) using a joining method such as a hot melt adhesive or welding. The outer sheet layer and the inner sheet layer can be formed from two sheets 12S, 12H as shown in the illustrated example, or from a single sheet material. For example, in the latter case, the inner sheet layer and the outer sheet layer are respectively formed by the inner and outer portions of a single sheet material folded back at the edge of the waist opening WO (which may be the edge on the crotch side) in part or all of the exterior bodies 12F, 12B. The illustrated example shows the former case, in which the sheet material 12S forming the outer sheet layer in the lower waist portion is folded back around the waist opening WO side of the sheet material 12H forming the inner sheet layer in the lower waist portion and folded back inward, with this folded back portion 12r extending to cover the edge of the interior body 200 on the waist opening WO side. On the other hand, in the waist portion, the folded portion 12r serves as an inner sheet layer adjacent to the inside of the elastic member.

[0103] The exterior bodies 12F, 12B incorporate elastic members 16-19 to improve the fit around the wearer's waist, and form a stretchable region A2 that stretches elastically in the width direction WD in response to the stretching of the elastic members 16-19. In this stretchable region A2, the exterior bodies 12F, 12B contract in their natural length state as the elastic members contract, forming wrinkles or creases. When stretched in the longitudinal direction of the elastic members, they can be stretched to a predetermined stretch rate without wrinkles. The elastic members 16-19 can be elongated elastic members such as rubber threads (illustrated example), as well as known elastic members in strip, net, film, and other shapes, without any particular limitation. The elastic members 16-19 may be made of synthetic or natural rubber.

[0104] To explain the elastic members 16-19 in the illustrated example in more detail, a plurality of waist elastic members 17 are attached to the waist portion W of the outer bodies 12F, 12B at intervals in the front-to-rear direction so as to be continuous over the entire width direction WD. Of the waist elastic members 17, one or more arranged in the region adjacent to the lower waist portion U may overlap the inner body 200, or may be provided on both sides in the width direction except for the central portion in the width direction that overlaps with the inner body 200. The waist elastic members 17 should have a thickness of 155-1880 dtex, particularly about 470-1240 dtex (in the case of synthetic rubber; in the case of natural rubber, a cross-sectional area of ​​0.05-1.5 mm). 2 , especially 0.1 to 1.0 mm 2 It is preferable to provide about 2 to 15, and especially about 4 to 10, rubber threads of about 1 / 4" thick (approximately 1 / 4" thick) at intervals of 2 to 12 mm, especially 3 to 7 mm, and the resulting elongation rate in the width direction WD of the waist portion W is preferably about 150 to 400%, especially about 220 to 320%. Furthermore, it is not necessary for the waist portion W to use elastic members of the same thickness or to have the same elongation rate all along the front-to-back direction LD, and for example, the thickness or elongation rate may be different in some areas.

[0105] Additionally, a plurality of lower waist elastic members 16, 19 made of elongated elastic members are attached to the lower waist portion U of the exterior bodies 12F, 12B at intervals in the front-to-back direction to form a lower waist stretchable region (a region having lower waist elastic members 16, 19). The lower waist elastic members 16, 19 have a thickness of 155 to 1880 dtex, particularly about 470 to 1240 dtex (in the case of synthetic rubber, or a cross-sectional area of ​​0.05 to 1.5 mm in the case of natural rubber). 2 , especially 0.1 to 1.0 mm 2 It is preferable to provide about 5 to 30 elastic threads of about 100 mm thick (approximately 1 / 2" thick) at intervals of 1 to 15 mm, especially 3 to 8 mm, and the resulting elongation rate in the width direction WD of the waist lower portion U is preferably about 200 to 350%, especially about 240 to 300%. Furthermore, it is not necessary for the waist lower portion U to use elastic members of the same thickness or have the same elongation rate all over its front-to-back direction LD, and thicknesses and elongation rates may vary in some areas.

[0106] When elastic members 16, 19 are provided in the front-to-back range including the absorbent body 56, as in the lower waist portion U in the illustrated example, in order to prevent contraction of the absorbent body 56 in the width direction WD in part or all of the region, it is preferable to designate the widthwise middle portion, including part or all of the portion overlapping with the absorbent body 56, as a non-elasticated region A1, and designate both sides of the non-elasticated region A1 as elasticated regions A2 (in the illustrated example, these are lower-waist elasticated regions). The widthwise dimension of the elasticated regions A2 provided on both sides of the non-elasticated region A1 may be substantially constant in the front-to-back direction LD as in the illustrated example, or may vary in the front-to-back direction LD, although not shown. Furthermore, the widthwise dimension of the elasticated regions A2 provided on both sides of the non-elasticated region A1 in the width direction WD may be substantially the same in the front body portion F and the back body portion B, or may be different.

[0107] The stretchable region A2 and non-stretchable region A1 can be constructed by attaching elastic members 16-17, 19 between the inner and outer sheet layers, and then cutting the elastic members 16, 19 into small pieces by applying pressure and heat or cutting them at one location in the middle of the width of the region that will become the non-stretchable region A1, or across almost the entire region, leaving stretchability in the stretchable region A2 while eliminating stretchability in the non-stretchable region A1. Note that unnecessary elastic members 18 that do not substantially contribute to the formation of stretchability will remain in the non-stretchable region A1.

[0108] The sheet materials 12S, 12H forming the inner and outer sheet layers can be used without any particular limitation, but nonwoven fabric is preferred. When nonwoven fabric is used, the basis weight per sheet is 10 to 30 g / m 2 It is preferable to set it to about this level.

[0109] The elastic members 16-19 can be fixed to the exterior bodies 12F, 12B by known methods. The inner sheet layer and the outer sheet layer can also be joined to each other by known methods. For example, in the portions of the exterior bodies 12F, 12B having the elastic members 16-19, a hot melt adhesive HM can be applied only to the outer peripheral surfaces of the elastic members 16-19 using an application means such as a comb gun or a SureWrap nozzle, and the elastic members can then be sandwiched between the inner sheet layer and the outer sheet layer. The hot melt adhesive HM applied only to the outer peripheral surfaces of the elastic members 16-19 can then be used to fix the elastic members 16-19 to the inner sheet layer and the outer sheet layer, and the inner sheet layer and the outer sheet layer together.

[0110] (Interior body joint) The inner body 200 can be joined to the outer bodies 12F, 12B by a joining method that uses material welding, such as heat sealing or ultrasonic sealing, or by a hot melt adhesive. In the illustrated example, the inner body 200 is fixed to the inner surfaces of the outer bodies 12F, 12B via a hot melt adhesive that is applied to the back surface of the inner body 200, that is, in this case, the back surface of the liquid-impermeable sheet 11 and the base portions 65 of the rising gathers 60. The inner body joining portion 201 that joins the inner body 200 and the outer bodies 12F, 12B can be provided over almost the entire overlapping area, as shown in Figure 2, and can also be provided in a portion excluding both widthwise ends of the inner body 200, for example.

[0111] <Explanation of terms used in the specification> In the present specification, the following terms have the following meanings unless otherwise specified in the specification.

[0112] "Front-rear direction" refers to the direction indicated by the symbol LD in the drawing (longitudinal direction), and "width direction" refers to the direction indicated by the symbol WD in the drawing (left-right direction), with the front-rear direction and width direction being perpendicular to each other.

[0113] "Front side" means the side closest to the wearer's skin when worn, and "reverse side" means the side farthest from the wearer's skin when worn.

[0114] "Front" means the side closest to the wearer's skin when worn, and "back" means the side away from the wearer's skin when worn.

[0115] "Elongation rate" refers to the value when the natural length is 100%. For example, an elongation rate of 200% is equivalent to an elongation ratio of 2 times.

[0116] "Artificial urine" is a mixture of 2 wt% urea, 0.8 wt% sodium chloride, 0.03 wt% calcium chloride dihydrate, 0.08 wt% magnesium sulfate heptahydrate, and 97.09 wt% ion-exchanged water.

[0117] "Gel strength" is measured as follows: 1.0 g of superabsorbent polymer is added to 49.0 g of artificial urine and stirred with a stirrer. The resulting gel is left in a constant temperature and humidity chamber at 40°C and 60% RH for 3 hours, then returned to room temperature, and the gel strength is measured using a card meter (I.techno Engineering: Curdmeter-MAX ME-500).

[0118] "Basis weight" is measured as follows: After pre-drying the sample or test piece, leave it in a test room or device under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%) until it reaches a constant weight. Pre-drying refers to bringing the sample or test piece to a constant weight in an environment at a temperature of 100°C. Note that pre-drying is not necessary for fibers with an official moisture regain of 0.0%. From the test piece that has reached a constant weight, use a sample collection template (100mm x 100mm) to cut out a sample measuring 100mm x 100mm. Measure the weight of the sample and multiply it by 100 to calculate the weight per square meter, which is the basis weight.

[0119] The "thickness" of thick members such as the absorber 56 and the absorption element 50 is measured using a thickness measuring device (Peacock, Dial Thickness Gauge, Model JB (measuring range 0 to 35 mm, measuring area 20 mm diameter circular terminal, measuring force approximately 3.0 N, pressure approximately 30 KPa)) manufactured by Ozaki Manufacturing Co., Ltd., with the sample and the thickness measuring device positioned horizontally.

[0120] The "thickness" of the bottom 51 of the groove 53 is calculated by subtracting the depth of the groove 53 from the thickness of the absorbent element 50 (non-compressed portion 52).

[0121] The "depth" of the groove 53 is measured using a Keyence Corporation One-Shot 3D Measuring Macroscope VR-3200 or its equivalent, the observation application "VR-H2V," and the analysis application "VR-H2A," or their equivalent software. Generally, the measurement magnification is 12x and the field of view is 24mm x 18mm. However, the magnification and field of view can be changed depending on the size of the groove 53. To measure the specific depth, the observation application is launched, a sample is placed on the microscope stage so that the groove 53 to be measured is positioned within the field of view, and the "Measure" button is pressed. Next, the analysis application is executed to analyze the measured 3D information. The analysis procedure is described below with reference to Figure 19. Specifically, the analysis application is used to obtain a depth (measured cross-sectional curve) profile along line Q1, which intersects the area other than the intersection of the groove 53 in the image area (XY area in the figure) shown in planar perspective. The cross-sectional curve of this depth profile is filtered using a low-pass filter to remove surface roughness components with wavelengths shorter than λc:800 μm (where λc is the "filter defining the boundary between roughness and waviness components" as described in JIS-B0601, section 3.1.1.2). The image portion (XZ portion in the figure) shown from a cross-sectional perspective is then filtered to obtain a "contour curve Q2." Two boundary points P1 and P2 are defined as the positions where the curve is nearly flat or where the curve is most pronounced upward. The minimum height value 51L of the range between these boundary points P1 and P2 is then calculated. Furthermore, the average value of the height values ​​of boundary points P1 and P2 is defined as the maximum height. The depth of groove 53 can then be calculated by subtracting minimum height value 51L from the maximum height value. The two boundary points P1 and P2 are visually selected. The planar image of the groove 53 being measured may be used as a reference for this selection. The above measurements are carried out at 10 arbitrary locations other than the intersections of the groove 53 designed to have the same dimensions and shape, and the results are taken as the average value.

[0122] The "thickness" of thin sheets such as nonwoven fabrics was measured using an automatic thickness measuring device (KES-G5 handy compression measurement program) with a load of 0.098 N / cm 2 , and pressure area: 2cm 2The measurement is automatically performed under the following conditions: The "thickness" of the packaged nonwoven fabric refers to the thickness of the portion where the thickness 50t of the absorbent element 50 is at its maximum.

[0123] The "layer thickness" of the nonwoven fabric is determined by observing the cross section of the target layer at the point where the thickness 50t of the absorption element 50 is at its maximum using a microscope (optical microscope, SEM, etc.) at 1000x magnification, measuring the apparent thickness at five randomly selected measurement points, and calculating the average value.

[0124] "Area ratio" means the proportion of the area of ​​the target portion per unit area, and is expressed as a percentage by dividing the total area of ​​the target portion (e.g., bottom 51 of groove 53) in the entire target area (e.g., the back surface of absorbent element 50) by the area of ​​the target area. When calculating the area ratio of bottom 51 of groove 53, a rectangular area of ​​any area including one or more unit frames 51f is aligned with the field of view, and the area of ​​bottom 51 of groove 53, which will be described later, is calculated.

[0125] The area of ​​the bottom 51 of the groove 53 is measured using a Keyence Corporation One-Shot 3D Measuring Macroscope VR-3200 or its equivalent, the observation application "VR-H2V," and the analysis application "VR-H2A," or their equivalent software. Generally, the measurement magnification is 12x and the field of view is 24mm x 18mm. However, the magnification and field of view can be changed depending on the size of the groove 53. Specifically, to measure the area, the observation application is launched, the sample is placed on the microscope stage so that the groove 53 to be measured is positioned within the field of view, and the "Measure" button is pressed. Next, the analysis application is launched, and to analyze the measured 3D information, the "Volume / Area" button is pressed to move to the volume / area measurement screen. On the volume / area measurement screen, the "Recess" button is pressed, the "Set Measurement Area" button is pressed, and then the "Minimum Height" button in "Auxiliary Tools 2" is pressed to specify an area that includes the groove 53, and the lowest point within the displayed area is selected. Next, select "Auto Extraction (Level)" from "Element Tools," then specify the lowest point as the reference point, set the height of the intersection setting to +0.25 mm, and press the "OK" button. Return to the volume / area measurement screen, and use the value displayed as the area of ​​the portion from the lowest point to a height of 0.25 mm within the specified region as the area of ​​the bottom 51 of the groove 53 in the field of view.

[0126] The water absorption capacity is measured according to JIS K7223-1996 "Test method for water absorption capacity of superabsorbent resins."

[0127] 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."

[0128] "Deployed state" means a flat, deployed state without contraction (including any contraction, such as contraction due to elastic members) or slack.

[0129] Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not in the natural length state.

[0130] 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 of 23±1°C, relative humidity of 50±2%). [Industrial Applicability]

[0131] The present invention can be used for all types of disposable diapers, including pants-type disposable diapers, tape-type disposable diapers, and pad-type disposable diapers. [Explanation of symbols]

[0132] 11...liquid-impermeable sheet, 12A...side seal, 12B...rear outer body, 12E...waist extension portion, 12F, 12B...outer body, 12F...front outer body, 12S, 12H...sheet material, 13...cover nonwoven fabric, 16, 19...waist lower elastic member, 17...waist elastic member, 18...unnecessary elastic member, 200...inner body, 201...inner body joint portion, 30...top sheet, 40...intermediate sheet, 50...absorbent element, 50A, 50C...side region, 50B...center region, 50N...non-reinforced region, 50R...reinforced region, 51...bottom, 51f...unit frame, 52...non-compressed portion, 53...groove, 56...absorbent body, 56L...low basis weight portion, 58...packaging sheet, 60...rising gathers, 60A...tip side portion, 60B...base side portion minutes, 62...gathered sheet, 63...gathered elastic member, 67...falling portion, 68...rising portion, 70...side flap, 71...first sheet layer, 72...second sheet layer, 73...side elastic member, 90...anvil roll, 91...projection portion, 92...smooth roll, A1...non-stretchable region, A2...stretchable region, B...back body, C...buttocks covering portion, F...front body, HM...hot melt adhesive, HM1...first hot melt adhesive, HM2...second hot melt adhesive, HM3...third hot melt adhesive, L...middle region, LD...front and rear direction, LO...leg opening, M...crotch region, SG...side stretchable region, SP...urine receiving space, T...torso region, U...lower waist portion, W...waist portion, WD...width direction, WO...waist opening.

Claims

1. The garment has a crotch portion and a front portion and a rear portion extending forward and rearward from the crotch portion, respectively; an absorbent element including an absorbent body provided in a range in the front-rear direction including the crotch area and a packaging sheet that wraps the absorbent body; The absorbent body has a layer formed by mixing and accumulating pulp fibers and superabsorbent polymer particles, At least a portion of the absorbent body located in the crotch region has a plurality of elongated low basis weight portions extending in the front-rear direction and spaced apart in the width direction, The low basis weight portion is a portion having a basis weight lower than that of the entire surrounding area, The absorbent element has a center region defined between a first low basis weight portion located closest to one side in the width direction and a second low basis weight portion located closest to the other side in the width direction, and a pair of side regions defined between the first low basis weight portion and an edge on one side of the absorbent body, and between the second low basis weight portion and an edge on the other side of the absorbent body, In the center region and the side regions, grooves are provided in a grid pattern, each groove extending from the front or back surface of the absorbent element to the absorbent body and having a bottom compressed in the thickness direction; The center region has a reinforcement region in which grooves deeper than the grooves in the side regions are arranged in a grid pattern. A disposable diaper characterized by:

2. the grooves are provided in a uniform grid pattern throughout the center region and the side regions; the depth of the groove is 60 to 90% of the maximum thickness of the absorbent element; The depth of the grooves in the reinforcement region is 1.1 to 1.6 times the depth of the grooves in the side region. The disposable diaper according to claim 1.

3. The basis weight of the pulp fibers in the absorbent body is 100 to 450 g / m ２ and the weight ratio of the pulp fibers to the superabsorbent polymer particles in the absorbent body is 30:70 to 70:30; The maximum thickness of the absorbent element is 4 to 35 mm, The width of the bottom is 1 to 3 mm, The area ratio of the bottom of the groove to the surface of the absorbent element is 10 to 14%. The disposable diaper according to claim 2.

4. The center region has a non-reinforced region across the entire width of the front side, the non-reinforced region having the same depth as or shallower than the grooves in the side regions. The disposable diaper according to any one of claims 1 to 3.

5. Both side edges of the reinforcing region are located on both side edges of the center region, respectively. The disposable diaper according to any one of claims 1 to 3.

6. The basis weight of the absorbent body in the reinforcement region is 1.1 to 1.6 times the basis weight of the absorbent body in the side region. The disposable diaper according to any one of claims 1 to 3.

7. a liquid-permeable top sheet that is provided on the outer side of the absorbent body and forms a surface that comes into contact with the wearer's skin; an intermediate sheet provided between the top sheet and the absorbent body, The side edges of the intermediate sheet are located at the same position as the side edges of the center region or closer to the center in the width direction. The disposable diaper according to any one of claims 1 to 3.

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