Absorbent article

Abstract

To hardly transmit gritty feeling of high-absorbent polymer particles.SOLUTION: An absorbent article includes an absorption element 50 including an absorber 56 and a packaging non-woven fabric 58 for packaging the absorber 56. The absorber 56 includes a layer constituted by mixing and accumulating a pulp fiber and high-absorbent polymer particles. When the absorption element 50 is divided into three regions of a first region 50A, a second region 50B, and a third region 50C in a width direction WD, a groove 53 which is dented from a surface of the absorption element 50 to the inside of the absorber 56 and has a bottom part 51 compressed in a thickness direction is provided in a lattice state in the first region 50A and the third region 50C positioned on both sides in the width direction WD and in the second region 50B positioned in the middle in the width direction WD. A depth of the groove 53 in the first region 50A and the third region 50C is shallower than a depth of the groove 53 in the second region 50B.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] This invention relates to absorbent articles such as disposable diapers. [Background technology]

[0002] Absorbent articles generally use absorbents made by mixing and accumulating pulp fibers and superabsorbent polymer particles. Such absorbents are typically incorporated as absorbent elements wrapped in packaging sheets made of crepe paper or the like to improve shape retention during and after manufacturing (see, for example, Patent Documents 1 and 2).

[0003] The absorbent elements of absorbent materials are held between the legs and subjected to forces from both sides in various directions due to leg movements such as walking. Therefore, good fit in the groin area is required, as is shape retention to prevent deformation such as twisting or cracking of the absorbent material. Of course, in the case of disposable diapers, ensuring absorbent performance in the groin area is also required.

[0004] As a method to improve the shape retention of absorbents, it is known to create grooves with a bottom where the absorbent element is compressed in the thickness direction by embossing, etc., in a grid-like or other pattern (see, for example, Patent Documents 1 and 2). However, if the packaging sheet that encloses the absorbent is crepe paper, the crepe paper may tear at the edges of the compressed parts or between adjacent compressed parts when forming the compressed parts. In addition, crepe paper loses strength and becomes more prone to tearing when it is wet from absorbing excrement. If the packaging sheet tears, superabsorbent polymer particles may escape from there and come out onto the surface of the absorbent article, which is undesirable.

[0005] It is known that fine-mesh nonwoven fabric (hereinafter referred to as "packaging nonwoven fabric") can be used as the packaging sheet. However, when packaging nonwoven fabric is used, there is a problem in that when you run your finger along the bottom of the grooves formed on the surface of the absorbent element, you can feel the gritty texture of the superabsorbent polymer particles. This gritty texture is undesirable because if the user feels it, it may worsen the wearing comfort or damage the product image. In particular, the areas on both sides of the absorbent element are areas that are easily pressed against the wearer's skin, so it is preferable to have as little of this gritty texture as possible. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-000236 [Patent Document 2] Patent No. 6380454 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the main objective of the present invention is to make it less likely for the user to perceive the gritty texture of the superabsorbent polymer particles when using nonwoven packaging fabric. [Means for solving the problem]

[0008] The absorbent articles that solve the above problems are as follows: <First aspect> It has a crotch area and a front portion and a rear portion that extend forward and backward from the crotch area, respectively. The absorbent element comprises an absorbent body provided in a position including the groin area, and a nonwoven fabric packaging that encloses the absorbent body. The absorbent material has a layer formed by mixing and accumulating pulp fibers and superabsorbent polymer particles. When the absorbent element is divided into three regions in the width direction, the first and third regions located on both sides in the width direction, and the second region located in the middle in the width direction, are provided in a grid pattern with grooves that are recessed from the surface of the absorbent element into the absorbent body and have a bottom that is compressed in the thickness direction, The depth of the grooves in the first and third regions is shallower than the depth of the grooves in the second region. An absorbent article characterized by the following features.

[0009] (Effects and Benefits) When using nonwoven packaging fabric, if a groove with a compressed bottom in the thickness direction is formed on the surface of the absorbent element, the nonwoven packaging fabric and absorbent material are compressed in the thickness direction at the bottom of the groove. As a result, the amount of superabsorbent polymer particles on and near the surface of the absorbent material increases relatively. Simultaneously, the cushioning capacity of the nonwoven packaging fabric and absorbent material decreases and they become denser in the thickness direction. This causes the superabsorbent polymer particles to remain in a state where they are difficult to move on and near the surface of the hardened absorbent material, and they are then covered by the thinned nonwoven packaging fabric. Therefore, if you run your finger along the surface at the bottom of the groove, you will feel a gritty texture due to the superabsorbent polymer particles. This texture becomes stronger depending on the degree of compression. Furthermore, as mentioned above, the areas where the absorbent elements are located are also areas that are more likely to be pressed against the wearer's skin, so there is a higher risk of feeling a gritty sensation there compared to other areas. In contrast, in this absorbent article, the depth of the grooves in the first and third regions located on both sides in the width direction is shallower than the depth of the grooves in the second region (i.e., the degree of compression at the bottom of the grooves in the first and third regions is weaker and the density is lower than the degree of compression at the bottom of the grooves in the second region). Compared to the case where the groove depth is constant, the increase in the amount of superabsorbent polymer particles on and near the surface of the absorbent is suppressed in the parts with the first and third regions that are more easily pressed against the wearer's skin. At the same time, the decrease in buffering capacity and densification in the thickness direction of the packaging nonwoven fabric and the absorbent are also suppressed. As a result, the gritty feeling of the superabsorbent polymer particles is less likely to be transmitted to the user, or if it is transmitted, the feeling is weaker. Also, in the second region, as well as in the first and third regions, grooves having a bottom that is recessed from the surface of the absorption element into the absorber and compressed in the thickness direction are provided in a lattice pattern, thereby ensuring liquid diffusibility, shape retention of the absorber, and the like.

[0010] <Second Aspect> The basis weight of the pulp fibers in the absorber is 100 to 450 g / m 2 and the pulp fibers: superabsorbent polymer particles in the absorber are in a weight ratio of 30:70 to 70:30, the maximum value of the thickness of the absorption element is 4 to 35 mm, the thickness of the bottom is 10 to 30% of the maximum value of the thickness of the absorption element, the depth of the grooves in the first region and the third region is 0.6 to 0.85 times the depth of the grooves in the second region, An absorbent article of the first aspect.

[0011] (Function and Effect) The material composition of the absorber and the degree of compression of the bottom of the grooves can be appropriately determined, but it is preferable to be within the range of this aspect.

[0012] <Third Aspect> the width of the bottom is 1 to 3 mm, the grooves are continuously lattice-shaped, An absorbent article of the second aspect.

[0013] (Function and Effect) The dimensions and shapes of the grooves and the like can be appropriately determined, but being formed in a diagonal lattice pattern as in this aspect is preferable because it is excellent not only in shape retention and flexibility of the absorber but also in liquid diffusibility.

[0014] <Fourth Aspect> The packaging nonwoven fabric has one or more meltblown layers and one or more protective layers, the basis weight of the packaging nonwoven fabric is 10 to 17 g / m 2 and The constituent fibers of the protective layer are fibers with an average fiber diameter of 10 to 25 μm. The constituent fibers of the meltblown layer are fibers with an average fiber diameter of 5 μm or less. With five layers of the aforementioned nonwoven packaging fabric stacked together, the air permeability measured according to JIS L 1096:2010 using Method A (Fragile method) is 25.5 to 70.0 cm². 3 / cm 2 ·s The aforementioned packaging nonwoven fabric has an elongation rate of 20-100% in the front-to-back direction under standard conditions as defined in JIS L 1913:2010. The elongation rate in the width direction, as specified in JIS L 1913:2010 under standard conditions, is 20-110%. An absorbent article in any one of the first to third embodiments.

[0015] (Effects and Benefits) If the packaging nonwoven fabric is not easily stretchable, it becomes difficult to form firm grooves, and the flexibility of the absorbent elements also decreases. Furthermore, as the packaging nonwoven fabric stretches and thins due to groove formation, and the interfiber gaps expand, the superabsorbent polymer particles can more easily pass through the packaging nonwoven fabric. Therefore, it is preferable to use a nonwoven fabric that is sufficiently thin and stretchable, as in this embodiment, and has a dense meltblown layer. Incidentally, air permeability can also be an indicator of how easily the superabsorbent polymer particles can escape.

[0016] <Fifth aspect> The basis weight of the absorbent in the first and third regions is 0.65 to 0.85 times that of the absorbent in the second region. An absorbent article in any one of the first to fourth embodiments.

[0017] (Effects and Benefits) In order to make the groove depth in the first and third regions shallower than the groove depth in the second region, for example, when forming grooves by embossing using an anvil roll, the height of the protrusions on the surface of the anvil roll may be changed. However, as in this embodiment, changing the basis weight of the absorber changes the thickness of the absorber, and even when using a normal anvil roll with uniform protrusion heights, it is possible to make the groove depth in the first and third regions shallower than the groove depth in the second region, which is preferable.

[0018] <Sixth aspect> The absorbing element has a top sheet adjacent to its surface, The widthwise ends of the absorbing element are not covered by the top sheet. The widthwise ends of the top sheet are non-bonded regions that are not bonded to the surface of the absorbing element, while the regions between these non-bonded regions are bonded regions that are bonded to the surface of the absorbing element with a hot-melt adhesive. The first and third regions extend to the same extent as, or beyond the boundary between, the non-bonded region and the bonded region, towards the center in the width direction. An absorbent article in any one of the first to fifth embodiments.

[0019] (Effects and Benefits) One method to reduce material costs is to place the top sheet adjacent to the surface of the absorbent element and make the width of the top sheet narrower than the width of the absorbent element. In this case, it becomes possible to touch both sides of the surface of the absorbent element, but this in itself is not a problem as the outer surface of the absorbent element is covered by the packaging nonwoven fabric. However, the non-bonded region of the top sheet is at high risk of the top sheet peeling up and the feel of the superabsorbent polymer particles being transmitted to the user, or of superabsorbent polymer particles that have escaped from the absorbent element moving to the surface of the top sheet. In contrast, by defining the widths of the first and third regions as in this embodiment, the entire non-bonded region of the top sheet is preferable because it overlaps with the first and third regions, where the compression at the bottom of the groove is weaker (i.e., the feel of the superabsorbent polymer particles is weaker, and the superabsorbent polymer particles are less likely to escape).

[0020] <Seventh aspect> The packaging nonwoven fabric has a hot melt adhesive that adheres the inner surface to the outer surface of the absorbent, In the first and third regions, a hot melt adhesive is slotted to bond at least the lower surface of the packaging nonwoven fabric to the upper surface of the absorbent. In the second region, at least the lower surface of the nonwoven packaging fabric and the upper surface of the absorbent are intermittently applied. An absorbent article according to any one of the first to sixth embodiments.

[0021] (Effects and Benefits) In this embodiment, at the bottom of the grooves in the first and third regions, the feel of the superabsorbent polymer particles is blocked or significantly reduced by the hot melt adhesive, and the risk of superabsorbent polymer particles escaping from the surface of the absorbent element is also reduced because the interfiber gaps are eliminated or significantly narrowed.

[0022] <Eighth aspect> The basis weight of superabsorbent polymer particles in the first and third regions is less than the basis weight of superabsorbent polymer particles in the second region. An absorbent article according to any one of the first to sixth embodiments.

[0023] (Effects and Benefits) With the configuration described in this embodiment, the feel of the second region's superabsorbent polymer particles is less likely to become strong at the bottom of the grooves in the first and third regions, and the risk of superabsorbent polymer particles escaping from the surface of the absorbent element is also reduced. [Effects of the Invention]

[0024] According to the present invention, when using nonwoven fabric for packaging, advantages such as the reduced sensation of grittiness from the superabsorbent polymer particles are less likely to be felt by the user are obtained. [Brief explanation of the drawing]

[0025] [Figure 1] This is a plan view showing the inner surface of a pant-type disposable diaper in its unfolded state. [Figure 2] This is a plan view showing the outer surface of a pant-type disposable diaper in its unfolded state. [Figure 3] This is a cross-sectional view of section 2-2 in Figure 1. [Figure 4] This is a cross-sectional view of section 3-3 in Figure 1. [Figure 5] (a) A cross-sectional view of line 4-4 in Figure 1, and (b) a cross-sectional view of line 5-5 in Figure 1. [Figure 6] This is a perspective view of a pull-up type disposable diaper. [Figure 7] This is a plan view showing the outer surface of the interior unit in its deployed state, along with the outline of the exterior unit. [Figure 8] This is a plan view showing the surface of the absorbent material along with the outline of the packaging nonwoven fabric. [Figure 9] This is a cross-sectional view showing only the essential parts in an enlarged view. [Figure 10] This is a plan view of the absorption element. [Figure 11] This is a magnified view of the main part of the surface of the absorption element. [Figure 12] This is a cross-sectional view of section 7-7 in Figure 11. [Figure 13] This is a cross-sectional view showing the absorbent element before it is packaged in the nonwoven fabric packaging. [Figure 14] This is a cross-sectional view showing the absorbent element after it has been packaged in nonwoven fabric packaging, but before grooves are formed. [Figure 15] This is a cross-sectional view of another example corresponding to section 2-2 in Figure 1. [Figure 16] This is a cross-sectional view of another example corresponding to section 3-3 in Figure 1. [Figure 17] This is a plan view showing another example of an absorber. [Figure 18] This is a schematic diagram showing a method for manufacturing an absorbent element. [Figure 19] This is an explanatory diagram of the depth measurement method. [Figure 20] This is a schematic diagram of the test apparatus. [Modes for carrying out the invention]

[0026] The following describes a disposable diaper, specifically a pant-type disposable diaper, in detail with reference to the attached drawings. Each adjacent component in the thickness direction is fixed or joined as necessary, in the same way as known diapers, even in addition to the fixing or joining parts described below. The dotted pattern in the cross-sectional view indicates adhesives such as hot melt adhesives used as fixing or joining means. Hot melt adhesives can be applied by known methods such as slot coating, continuous linear 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 conjunction with these methods, in the fixing parts of elastic members, hot melt adhesive can be applied to the outer surface of the elastic member to fix the elastic member to the adjacent member. Examples of hot melt adhesives include EVA-based, adhesive rubber-based (elastomer-based), polyolefin-based, and polyester / polyamide-based adhesives, but they can be used without particular limitation. As fixing or joining means for joining each component, material welding methods such as heat sealing or ultrasonic sealing can also be used. 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 with hot melt adhesive, intermittent pattern coating such as spiral, Z-shaped, or wavy can be suitably used. When coating an area exceeding the coating width of a single nozzle, intermittent pattern coating such as spiral, Z-shaped, or wavy can be performed with or without gaps in the width direction. As a joining means for joining each component, material welding methods such as heat sealing or ultrasonic sealing can also be used.

[0027] Furthermore, in the following description, known nonwoven fabrics can be used as appropriate depending on the part and purpose. The constituent fibers of the nonwoven fabric can be selected without particular limitation, including, for example, polyolefin-based fibers such as polyethylene or polypropylene, polyester-based fibers, polyamide-based fibers, etc. (including single-component fibers as well as composite fibers such as core-sheath fibers), regenerated fibers such as rayon and cupro, and natural fibers such as cotton, and these can also be used in mixtures. To increase the flexibility of the nonwoven fabric, it is preferable to use crimped fibers as constituent fibers. In addition, the constituent fibers of the nonwoven fabric may be hydrophilic fibers (including fibers that have become hydrophilic due to a hydrophilizing agent), hydrophobic fibers, or water-repellent fibers (including fibers that have become water-repellent due to a water-repellent agent). Furthermore, nonwoven fabrics are generally classified according to the length of the fibers, the sheet formation method, the fiber bonding method, and the lamination structure into short fiber nonwoven fabrics, long fiber nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, thermal bond (air-through) nonwoven fabrics, needle punch nonwoven fabrics, point bond nonwoven fabrics, and laminated nonwoven fabrics (including SMS nonwoven fabrics and SMMS nonwoven fabrics, etc., which have a meltblown layer sandwiched between spunbond layers), and any of these nonwoven fabrics can be used.

[0028] Figures 1 to 6 show an example of a pant-type disposable diaper. This pant-type disposable diaper comprises a rectangular front outer body 12F that forms the front waist area and a rectangular rear outer body 12B that forms the rear waist area, 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 area M to the rear outer body 12B. The sides of the front outer body 12F and the sides of the rear outer body 12B are joined to form a side seal 12A, so that the openings formed by the front and rear ends of the outer bodies 12F and 12B become a waist opening WO through which the wearer's waist passes, and the parts enclosed by the lower edges of the outer bodies 12F and 12B and the side edges of the inner body 200 on both sides in the width direction become leg openings LO through which the legs pass. The inner body 200 is the part that absorbs and retains excrement such as urine, and the outer bodies 12F and 12B are the parts that 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 length in the front-to-back direction 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.

[0029] This pant-type disposable diaper has a waist area T defined as a front-to-back range with side seals 12A (a front-to-back range from the waist opening WO to the upper end of the leg opening LO), and an intermediate area L defined as a front-to-back range of the part that forms the leg opening LO (between the front-to-back range of the front body F with side seals 12A and the front-to-back range of the back body B with side seals 12A). The parts of the front outer body 12F and the back outer body 12B located in the waist area T, that is, the front waist area and the back waist area, can be conceptually divided into a "waist area" W that forms the edge of the waist opening and a "lower waist area" U which is the part below the waist area. Typically, if there are boundaries within the front and rear waist sections where the stretch stress in the width direction WD changes (for example, where the thickness or elongation rate of the elastic member changes), the waist section W extends from the boundary closest to the waist opening WO. If there are no such boundaries, the waist extension portion 12E that extends beyond the absorbent body 56 or inner body 200 toward the waist opening WO becomes the waist section W. The lengths of these sections in the front-to-back direction vary depending on the size of the product and can be determined as appropriate. For example, the waist section W can be 15-40 mm, and the lower waist section U can be 65-120 mm. On the other hand, both side edges of the intermediate region L are constricted in a U-shape or curved shape to conform to the wearer's legs, and this is where the wearer's legs are inserted. As a result, the unfolded pant-type disposable diaper has an overall hourglass shape.

[0030] (Interior structure) The inner lining 200 can take any shape, but in the illustrated example, it is a rectangle with its long sides forming the edges on both sides. As shown in Figures 3 to 5, the inner lining 200 comprises a top sheet 30 that faces the body, a liquid-impermeable sheet 11, and an absorbent element 50 interposed between them, and is responsible for absorption and retention functions. Reference numeral 60 indicates riser gathers 60 that extend from both sides of the inner lining 200 to contact the wearer's legs in order to prevent excrement from leaking out from both sides of the inner lining 200.

[0031] (Top sheet) The top sheet 30 is permeable to liquids and can be made of perforated or non-perforated nonwoven fabrics or perforated plastic sheets, for example. The top sheet 30 may consist of a single sheet or a laminated sheet obtained by bonding 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 be omitted.

[0032] The sides of the top sheet 30 may be folded over to the back of the absorbent element 50 at its side edges, or they may be left unfolded and protrude laterally beyond the side edges of the absorbent element 50, as shown in the examples in Figures 15 and 16. Alternatively, as shown in the examples in Figures 3 and 4, the overall width of the top sheet 30 may be shorter than the overall width of the absorbent element 50, so that both side edges of the top sheet 30 are positioned on the absorbent element 50 and both sides of the surface of the absorbent element 50 are exposed on the surface of the diaper.

[0033] To prevent misalignment of the top sheet 30 relative to the back-side component, it is desirable to fix it to the adjacent component on the back side using a joining method that involves material welding, such as heat sealing or ultrasonic sealing, or by using a hot-melt adhesive. In the illustrated example, the top sheet 30 is fixed to the adjacent component on the back side by a hot-melt adhesive applied to its back surface.

[0034] (Intermediate sheet) As shown in the examples in Figures 15 and 16, an intermediate sheet (also called a "second sheet") 40 can be provided, which has a faster liquid permeation rate than the top sheet 30, in order to quickly transfer the liquid that has permeated through the top sheet 30 to the absorbent material 56. This intermediate sheet 40 is intended to quickly transfer the liquid to the absorbent material, enhance the absorption performance of the absorbent material 56, and prevent the "backflow" phenomenon of the absorbed liquid from the absorbent material. As shown in Figures 1 to 5, the intermediate sheet 40 can also be omitted.

[0035] Examples of the intermediate sheet 40 include the same material as the top sheet 30, as well as spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point-bonded nonwoven fabric, or crepe paper. Air-through nonwoven fabric is particularly preferred due to its bulkiness. For air-through nonwoven fabric, it is preferable to use a composite fiber with a core-sheath structure. In this case, the resin used for the core may be polypropylene (PP), but polyester (PET), which has high rigidity, is preferred. The basis weight is 17-80 g / m². 2 Preferably, 25-60 g / m 2 This is more preferable. The thickness of the raw fibers for the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use off-center fibers without a core in the center, hollow fibers, or off-center and hollow fibers as all or part of the mixed fibers of the raw fibers.

[0036] In the illustrated example, the intermediate sheet 40 is shorter than the width of the absorbent body 56 and positioned in the center, but it may also be provided across the entire width. The length of the intermediate sheet 40 in the front-to-back direction may be the same as the total length of the diaper, the same as the length of the absorbent element 50, or it may be within a short length range centered on the area that receives liquid.

[0037] It is desirable to fix the intermediate sheet 40 to the adjacent member on the back side using a joining method that involves material welding, such as heat sealing or ultrasonic sealing, or by hot melt adhesive, for purposes such as preventing misalignment with the member on the back side. In the illustrated example, the intermediate sheet 40 is fixed to the surface of the portion of the packaging nonwoven fabric 58 that is located on the front side of the absorbent 56 by hot melt adhesive applied to its back surface.

[0038] (Liquid-impermeable sheet) The material of the liquid-impermeable sheet 11 is not particularly limited, but examples include plastic films made of polyolefin resins such as polyethylene and polypropylene, laminated nonwoven fabrics with a plastic film on the surface of a nonwoven fabric, and laminated sheets made by layering and bonding a nonwoven fabric to a plastic film. It is preferable to use a material that is both liquid-impermeable and breathable for the liquid-impermeable sheet 11, as this is preferred from the viewpoint of preventing stuffiness. As a breathable plastic film, a microporous plastic film obtained by kneading an inorganic filler into a polyolefin resin such as polyethylene or polypropylene, forming a sheet, and then stretching it in a uniaxial or biaxial direction is widely used. In addition to the above, nonwoven fabrics using microdenier fibers, nonwoven fabrics whose leak-proof properties are enhanced by reducing the voids in the fibers through the application of heat or pressure, and sheets that are made impermeable to liquids without using plastic films, such as those coated with superabsorbent resins, hydrophobic resins, or water-repellent agents, can also be used as impermeable sheets 11. However, it is desirable to use a resin film in order to obtain sufficient adhesive strength when bonding with the cover nonwoven fabric 13, which will be described later, via a hot-melt adhesive.

[0039] The liquid-impermeable sheet 11 is designed to fit behind the absorbent element 50, as shown in the figure. In addition, to enhance leak prevention, it can be extended around both sides of the absorbent element 50 to the sides of the top sheet 30 of the absorbent element 50. The width of this extended portion should be approximately 5 to 20 mm on each side.

[0040] (Absorption element) The absorbent element 50 comprises an absorbent body 56 and a nonwoven packaging fabric 58 that encloses the entire absorbent body 56.

[0041] (Absorbent) The absorbent material 56 is a mixture and aggregate of pulp fibers and superabsorbent polymer particles. The basis weight of the pulp fibers is, for example, 100 to 450 g / m². 2 It can be considered to be of a certain degree.

[0042] Pulp fibers can be used without particular limitations, as long as they are fibers extracted from wood, grass, or other plants by mechanical and / or chemical processing. As raw materials for pulp fibers, in addition to coniferous trees and hardwoods, bamboo, rice, kudzu, pampas grass, hemp, sugarcane, etc. can also be used. Artificial celluloses such as rayon and acetate can also be used. As pulp fibers, in addition to coniferous tree pulp fibers (pulp fibers derived from coniferous trees), hardwood pulp fibers (pulp fibers derived from hardwoods) which have a shorter average fiber length than coniferous tree pulp fibers can also be used, and either one of these may be used alone or both may be used in mixtures. Furthermore, the pulp fibers may contain recycled pulp fibers. For example, the pulp fibers may contain recycled coniferous tree pulp fibers and recycled hardwood pulp fibers.

[0043] In an absorbent material 56 made by mixing coniferous pulp fibers and hardwood pulp fibers, the fiber density is higher than that of an absorbent material 56 made solely of coniferous pulp fibers, which was commonly used in the past, because it includes not only fibers that are relatively long and wide, but also fibers that are relatively short and narrow. Therefore, not only is the liquid retention capacity of the fibers due to capillary action improved, but the superabsorbent polymer particles within the absorbent material 56 (between the pulp fibers) are also improved. child It is particularly preferable because it also improves retention.

[0044] Both the hardwood pulp fibers and softwood pulp fibers are preferably bleached hardwood kraft pulp (LBKP) and bleached softwood kraft pulp (NBKP) produced by the kraft process, but other materials such as soda pulp, sulfite pulp, chemothermetic pulp, chemi-finer mechanical pulp, and thermochemimetic pulp may also be used.

[0045] When using a mixture of coniferous pulp fibers and hardwood pulp fibers, the content of coniferous 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 the total pulp fibers in the absorbent body 56 consist substantially of coniferous pulp fibers and hardwood pulp fibers. Furthermore, the mass ratio of hardwood pulp fibers to other pulp fibers such as coniferous pulp fibers is not limited and can be, for example, 10 / 90 to 90 / 10, but from the viewpoint of operability, it is preferably 20 / 80 to 50 / 50, more preferably 25 / 75 to 38 / 62, even more preferably 25 / 75 or more and less than 38 / 62, even more preferably 26 / 74 to 36 / 64, and particularly preferably 28 / 72 to 35 / 65. In this specification, unless otherwise specified, the amount of pulp fibers or the material thereof refers to the amount added in an oven-dry state, i.e., the mass percentage in an oven-dry state.

[0046] When the absorbent material 56 contains hardwood pulp fibers, it is preferable that the proportion of pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm is 40% or more by mass, and the proportion of pulp fibers with a fiber width of 10 μm or more and less than 35 μm is 90% or more by mass. Furthermore, the proportion of pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm is preferably 42.6% or more, more preferably 43% or more, even more preferably 43.2% or more, 43.7% or more, and 45% or more. %The above can be achieved. Furthermore, the proportion of pulp fibers with a fiber width of 10 μm or more and less than 35 μm can preferably be 90.6% or more, more preferably 91.0% or more, even more preferably 91.2% or more, or 91.4% or more. In this way, by having the absorbent 56 contain specific pulp fiber lengths and specific pulp fiber widths within specific ranges, the advantages of using hardwood pulp fibers are further enhanced. There is no particular upper limit to the proportion of pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm, but due to variations in fiber length resulting from the pulp being a natural material, it may be 80% by mass or less, 60% by mass or less, or 55% by mass or less. Similarly, there is no particular upper limit to the proportion of pulp fibers with a fiber width of 10 μm or more and less than 35 μm, but it may be 98% by mass or less, 95% by mass or less, or 94% by mass or less.

[0047] Furthermore, the fiber length and fiber width of pulp fibers can be measured using the measuring instrument "VALMET FS5" in accordance with JIS-P8226:2011 (ISO16065-2:2007) "Pulp - Method for measuring fiber length by automated optical analysis".

[0048] Furthermore, when the absorbent material 56 contains hardwood pulp fibers, the average fiber length when pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm are measured at 0.02 mm intervals (with a classification width of 0.02 mm) can be set to 0.5 to 0.8 mm, preferably 0.6 to 0.7 mm. This makes it possible to suppress variations in the distribution of voids that may occur in the absorbent material 56 depending on the orientation direction of the pulp fibers.

[0049] Furthermore, when the absorbent material 56 contains hardwood pulp fibers, the standard deviation σ when measuring pulp fibers with a fiber length of 0.5 mm or more and less than 1.1 mm at 0.02 mm intervals (with a classification width of 0.02 mm) can be 0.58 mm or less, preferably 0.56 mm or less, more preferably 0.54 mm or less, and even more preferably 0.50 mm or less. Having the standard deviation within the above range further enhances the advantages of using hardwood pulp fibers.

[0050] Furthermore, when pulp fibers with a fiber width of 10 μm or more and less than 35 μm are measured at 1 μm intervals (with a classification width of 1 μm), the average fiber width is 15 μm or more and 30 μm or less, preferably 18 μm. m The average fiber width can be set to 27 μm or less. By keeping the average fiber width within the above range, it is possible to maintain an appropriate amount of space between fibers and prevent a decrease in absorption rate.

[0051] When pulp fibers with a fiber width of 10 μm or more and less than 35 μm are measured at 1 μm intervals (with a classification width of 1 μm), the standard deviation σ can be 2.9 μm or less, preferably 2.8 μm or less, more preferably 2.75 μm or less, even more preferably 2.6 μm or less, and 2.59 μm or less. By setting the standard deviation within the above range, the advantages of using hardwood pulp fibers become even more apparent.

[0052] Superabsorbent polymer particles include not only "particles" but also "powder." Superabsorbent polymer particles can be those used in this type of disposable diaper, and it is desirable that the percentage of particles remaining on the sieve after sieving (shaking for 5 minutes) using a 500 μm standard sieve (JIS Z8801-1:2006) is 30% by weight or less, and it is also desirable that the percentage of particles remaining on the sieve after sieving (shaking for 5 minutes) using a 180 μm standard sieve (JIS Z8801-1:2006) is 60% by weight or more.

[0053] While there are no particular limitations on the material used for the superabsorbent polymer particles, those with a water absorption capacity of 40 g / g or more are preferred. Examples of superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based materials. Starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked sodium carboxymethylcellulose, and acrylic acid (salt) polymers can be used. While the commonly used granular form is preferred for the superabsorbent polymer particles, other forms can also be used.

[0054] As the highly absorbent polymer particles, those having a water absorption rate of 70 seconds or less, particularly 40 seconds or less, are preferably used. If the water absorption rate is too slow, so-called reverse flow, in which the liquid supplied into the absorber 56 flows back out of the absorber 56, is likely to occur.

[0055] Also, as the highly absorbent polymer particles, those having a gel strength of 1000 Pa or more are preferably used. Thereby, even when the absorber 56 is bulky, the sticky feeling after liquid absorption can be effectively suppressed.

[0056] The basis weight of the highly absorbent polymer particles can be appropriately determined according to the absorption amount required for the use of the absorber 56. Therefore, although it cannot be generally stated, it can be 50 to 350 g / m 2 If the basis weight of the polymer is less than 50 g / m 2 it becomes difficult to secure the absorption amount. If it exceeds 350 g / m 2 the effect saturates.

[0057] The ratio of the pulp fibers and the highly absorbent polymer particles in the absorber 56 is not particularly limited. For example, the pulp fibers: highly absorbent polymer particles can be 40:60 to 65:35 in weight ratio. In particular, when the pulp fibers: highly absorbent polymer particles are 50:50 to 65:35 in weight ratio, it is preferable because the absorber 56 has excellent shape maintainability, absorption speed, ease of forming the groove 53 described later, etc., and the risk of the highly absorbent polymer particles coming out is low. Also, the highly absorbent polymer particles are preferably present substantially uniformly throughout the absorber 56.

[0058] The maximum thickness t2 of the absorber 56 is not particularly limited, but can be, for example, 3 to 15 mm.

[0059] The absorber 56 only needs to extend across both the front and rear sides of the crotch part M so as to include the crotch part M. In the case of a pant-type disposable diaper like this example, the absorber 56 preferably extends to the peripheral edge of the interior body 200 or the vicinity thereof in the longitudinal direction LD and the width direction WD. Note that the symbol 56X indicates the full width of the absorber 56.

[0060] To ensure sufficient absorption in the groin area M, the shape of the absorbent body 56 is preferably approximately rectangular, as shown in the example in Figure 8. Furthermore, to improve the fit in the groin area M, the shape of the absorbent body 56 can be constricted, as shown in the example in Figure 17(a), with the width of the absorbent body 56 in the groin area M being narrower than its front and rear sides. In this case, to ensure sufficient absorption in the groin area M, the width n1 of the narrowest part of the absorbent body 56 in the groin area M is preferably 0.85 times or more the total width 56X of the absorbent body 56.

[0061] The crotch area M refers to the area of ​​the front-to-back LD that has the constricted portion 56n, if the absorbent body 56 has the constricted portion 56n described later; if 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 shown in the illustrated example, it refers to the area of ​​the front-to-back LD that has 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); and if there is no constricted portion, it refers to the part located in the center of the front-to-back LD and where the dimension of the front-to-back LD is 20-30% of the total length of the product. The parts extending forward and backward from the crotch area M become the front part and the rear part, respectively.

[0062] (Low-profile section) As shown in Figures 8 and 17, the absorbent body 56 may have elongated low-weight portions 56L extending in the front-to-back direction LD on both sides in the width direction WD of the crotch area M, or it may not have low-weight portions 56L as shown in Figures 1 to 6. The low-weight portions 56L refer to areas with less weight and do not include areas where the weight does not change, such as the bottom 51 of the groove 53 described later, which is only compressed in the thickness direction. The low-weight portions 56L can also be slits that penetrate in the thickness direction, but it is preferable that they be recesses with a small accumulation of pulp fibers and superabsorbent polymer particles, as shown in the illustrated example, because it is easier to ensure absorption. These recesses may be formed on the surface or the back surface of the absorbent body 56. By providing such low-weight portions 56L on the absorbent body 56, the bending of the absorbent body 56 along the low-weight portions 56L is promoted, improving the fit of the absorbent element 50 in the crotch area M. The total basis weight of pulp fibers and superabsorbent polymer particles in the low basis weight section 56L should be less than the total basis weight of pulp fibers and superabsorbent polymer particles in the parts other than the low basis weight section 56L. For example, it can be 0.1 to 0.5 times the total basis weight of pulp fibers and superabsorbent polymer particles in the parts other than the low basis weight section 56L.

[0063] The low-weight portion 56L may extend linearly along the front-to-back direction LD, as long as it is elongated in the front-to-back direction LD, or it may curve so as it moves laterally toward both sides of the front-to-back direction LD, as shown in the illustrated example. The front and rear ends of the low-weight portion 56L can be shaped appropriately. For example, they may be straight as shown in the example in Figure 17(a), curved (e.g., semi-circular) as shown in the example in Figure 8, or, although not shown, the corners at both ends may be rounded and the middle section straight. The width m1 of the low-weight portion 56L can be determined appropriately. For example, it can be 0.04 to 0.1 times the width n1 of the narrowest part of the crotch area M of the absorbent body 56 (meaning the total width 56X in the case of a rectangle). The width m1 of the low-weight portion 56L may be constant in its length direction or may vary. The dimensions and arrangement of the low-weight portion 56L in the front-to-back direction LD can be determined appropriately. For example, the dimension m2 of the front-to-back LD of the low-weight portion 56L can be 50-120%, more preferably 50-80%, of the dimension of the front-to-back LD of the crotch portion M. Furthermore, even if the low-weight portion 56L is contained within the range of the crotch portion M, it may extend to the front, back, or both front and back sides of the crotch portion M.

[0064] The low-profile sections 56L are provided one on each side (left and right) of the width direction WD in the crotch area M, as well as one in the center of the width direction WD as shown in Figures 8 and 17(a), as shown in Figure 18(b), or one on each side of the width direction WD in the crotch area M, or one in the center of the width direction WD as shown in Figure 18(b).

[0065] (groove) Preferably, as shown in Figures 3, 4, and 9-11, the absorbent element 50 has grooves 53 arranged in a grid pattern, each groove 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. By arranging the grooves 53 on the surface of the absorbent element 50 in a grid pattern in this way, liquid diffusion and shape retention of the absorbent body 56 can be improved. The bottom 51 of the groove 53 is a high-density portion that has been compressed by pressing (direct pressure) and whose thickness is almost equal. Hereinafter, the portion other than the bottom 51 will be referred to as the uncompressed portion 52. The uncompressed portion 52 is thicker and lower in density than the bottom 51, but even in the uncompressed portion 52, near the bottom 51, the absorbent body 56 and the packaging nonwoven fabric 58 deform as if being pulled by the deformation of the bottom 51, resulting in an increase in density as it approaches the bottom 51. As long as the uncompressible portion 52 is thicker and less dense than the bottom portion 51, the entire uncompressible portion 52 may be compressed in the thickness direction simultaneously with, before, or after the compression process that forms the bottom portion 51. The shape and arrangement of the uncompressible portion 52 are determined according to the shape and arrangement of the bottom portion 51.

[0066] When the absorption element 50 is divided into three regions in the width direction WD, namely a first region 50A, a second region 50B, and a third region 50C, it is preferable that the grooves 53 are provided in the first region 50A and the third region 50C located on both sides of the width direction WD, and in the second region 50B located in the middle of the width direction WD. In this case, as long as the grooves 53 are provided in all of the first region 50A, the second region 50B, and the third region 50C, the grid patterns of the grooves 53 in each region may be different, or the patterns of the grooves 53 in adjacent regions may be separated, but it is preferable that the grooves 53 are provided in a single grid pattern that spans all of the first region 50A, the second region 50B, and the third region 50C, as shown in the illustrated example.

[0067] When using the packaging nonwoven fabric 58, if a groove 53 having a compressed bottom 51 in the thickness direction is formed on the surface of the absorbent element 50, the packaging nonwoven fabric 58 and the absorbent body 56 are compressed in the thickness direction at the bottom 51 of the groove 53. As a result, the amount of superabsorbent polymer particles on and near the surface of the absorbent body 56 increases relatively, and the cushioning capacity of the packaging nonwoven fabric 58 and the absorbent body 56 decreases and they become denser in the thickness direction. This causes the superabsorbent polymer particles to remain in a state where they are difficult to move on and near the surface of the hardened absorbent body 56, and they are covered by the thinned packaging nonwoven fabric 58. Therefore, if you run your finger over the surface of the top sheet 30 at the bottom 51 of the groove 53, you will feel a gritty sensation from the superabsorbent polymer particles. This sensation becomes stronger depending on the degree of compression. Also, the areas on both sides of the absorbent element 50 are areas that are easily pressed against the wearer's skin, so there is a higher risk of such a gritty sensation being transmitted there compared to other areas.

[0068] Therefore, it is preferable that the depth d1 of the grooves 53 in the first region 50A and the third region 50C, located on both sides in the width direction WD, be shallower than the depth d2 of the grooves 53 in the second region 50B. The ratio of these depths d1 and d2 can be determined as appropriate, but in the usual case, the depth d1 of the grooves 53 in the first region 50A and the third region 50C is preferably 0.6 to 0.85 times the depth d2 of the grooves 53 in the second region 50B. The depth d2 of the grooves 53 in the second region 50B can be determined as appropriate, but can be about 2.5 to 11 mm. In addition, the density of the bottom 51 of the grooves 53 in the first region 50A and the third region 50C is 120 to 210 kg / m³. 3 Especially 130-150 kg / m 3 It is preferable that this is the case. On the other hand, the density of the bottom 51 of the groove 53 in the second region 50B is 190 to 300 kg / m 3 Especially 200-220 kg / m 3 It is preferable that this be the case.

[0069] In the grooves 53 formed by compression in the thickness direction, the depths d1 and d2 of the grooves 53 represent the degree of compression at the bottom 51 of the grooves 53. Therefore, if the depth d1 of the grooves 53 in the first region 50A and the third region 50C is shallower than the depth d2 of the grooves 53 in the second region 50B, the degree of compression at the bottom 51 of the grooves 53 in the first region 50A and the third region 50C will be weaker and denser than the degree of compression at the bottom 51 of the grooves 53 in the second region 50B. As a result, the increase in the amount of superabsorbent polymer particles on and near the surface of the absorbent material 56 is suppressed in the parts with the first region 50A and the third region 50C, which are more likely to be pressed against the wearer's skin. At the same time, the decrease in the cushioning capacity and densification in the thickness direction of the packaging nonwoven fabric 58 and the absorbent material 56 are also suppressed, making it difficult for the gritty feeling of the superabsorbent polymer particles to be transmitted to the user, or if it is transmitted, the feeling will be weaker. Furthermore, in the second region 50B as well as the first region 50A and the third region 50C, grooves 53 having a bottom 51 that is recessed from the surface of the absorbing element 50 into the absorber 56 and compressed in the thickness direction are provided in a grid pattern, thereby ensuring liquid diffusion and shape retention of the absorber 56.

[0070] From this perspective, it is preferable that the basis weight of the superabsorbent polymer particles in the first region 50A and the third region 50C is less than the basis weight of the superabsorbent polymer particles in the second region 50B. For example, the basis weight of the superabsorbent polymer particles in the second region 50B is 190 to 330 g / m². 2 In this case, the basis weight of the superabsorbent polymer particles in the first region 50A and the third region 50C can be approximately 0.5 to 0.8 times that of the superabsorbent polymer particles in the second region 50B.

[0071] Such an absorbent element 50 can be manufactured by known methods such as embossing. For example, an absorbent element 50 having a groove 53 can be manufactured by a first step of forming an absorbent body 56 made by mixing and accumulating pulp fibers and superabsorbent polymer particles; a second step of forming a package body by wrapping the entire absorbent body 56 with a nonwoven packaging fabric 58; and a third step, as shown in Figure 18, passing the package body 50P between an anvil roll 90 having a number of protrusions 91 arranged at intervals on its outer circumference in the same pattern as the bottom 51 of the groove 53 and a smooth roll 92 having a cylindrical surface (without the protrusions 91) opposite to it, with the surface that will become the back of the absorbent element 50 facing the anvil roll 90, and pressing the portion of the package body 50P sandwiched between the number of protrusions 91 of the anvil roll 90 and the smooth roll 92, thereby forming a groove 53 having a bottom 51 compressed in the thickness direction. Either one or both of the anvil roll 90 and the smooth roll 92 may be heated while pressing, or they may be pressed without heating. In the third step, only the portion of the package 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 package 50P may be pressed while pressing the portion sandwiched between the numerous protrusions 91 of the anvil roll 90 and the smooth roll 92 to the deepest extent.

[0072] In order to make the depth d1 of the grooves 53 in the first region 50A and the third region 50C shallower than the depth d2 of the grooves 53 in the second region 50B, when forming the grooves 53 by embossing using an anvil roll 90, for example, the height of the protrusions on the surface of the anvil roll 90 may be changed. However, in the step of forming the absorber 56, if the basis weight of the absorber 56 in the first region 50A and the third region 50C is made less than the basis weight of the absorber 56 in the second region 50B, for example, about 0.65 to 0.85 times, and the thickness t1 of the absorber 56 in the first region 50A and the third region 50C is made thinner than the thickness t2 of the absorber 56 in the second region 50B, it is preferable that even when using a normal anvil roll 90 with uniform protrusion heights, the depth d1 of the grooves 53 in the first region 50A and the third region 50C can be made shallower than the depth d2 of the grooves 53 in the second region 50B.

[0073] When the basis weight of the absorber 56 in the first region 50A and the third region 50C is reduced compared to the basis weight of the absorber 56 in the second region 50B (making the thickness t1 of the absorber 56 in the first region 50A and the third region 50C thinner than the thickness t2 of the absorber 56 in the second region 50B), there may be steps at the boundary between the first region 50A and the second region 50B, and at the boundary between the second region 50B and the third region 50C, as shown in the illustrated example. Alternatively, although not shown, there may be no steps, and the thickness may decrease continuously from the second region 50B to the first region 50A and the third region 50C. When there are steps, it is preferable that the steps be provided on the front side having the groove 53, but they may also be provided on the back side or on both sides.

[0074] The thickness 50t of the absorption element 50 and the thickness 51t of the bottom of the groove 51 can be determined as appropriate, but for example, the maximum value of the thickness 50t of the absorption element 50 (the maximum value of the thickness of the incompressible portion 52) can be 4 to 35 mm, and is particularly preferably 5 to 13 mm. The thickness 51t of the bottom 51 is usually preferably 15 to 35% of the maximum value of the thickness 50t of the absorption element 50, and more preferably 10 to 30%.

[0075] Preferably, the grooves 53 are continuous in a grid pattern, but they may also be arranged intermittently to form a grid. One preferred pattern of grooves 53 is a diagonal grid pattern consisting of a first part 51a extending in a direction inclined 40 to 50° clockwise with respect to the front-rear direction LD in a plan view, and a second part 51b extending in a direction inclined 40 to 50° counterclockwise with respect to the front-rear direction LD in a plan view, as shown in the example in Figures 10 and 11. In this case, the shape of the unit frame 51f is approximately rhombic. The dimensions of the unit frame 51f can be determined as appropriate, but for example, the dimension 51x in the width direction WD of the unit frame 51f can be about 15 to 20 mm. Also, the dimension 51y in the front-rear direction LD of the unit frame 51f can be about 15 to 20 mm.

[0076] The width 51w of the bottom 51 of the groove 53 can be determined as appropriate, but is usually preferably about 1 to 3 mm, and preferably is approximately constant in the direction of continuity of the groove 53.

[0077] The area ratio of the bottom 51 of the grooves 53 to the surface of the absorption element 50 can be determined as appropriate, but if the bottom 51 of the grooves 53 is excessively densely arranged, the absorption element 50 will become hard, so it is preferable to set it to about 10 to 14%.

[0078] The widths of the first region 50A and the third region 50C can be determined as appropriate. The widths of the first region 50A and the third region 50C can be, for example, about 1 / 10 to 1 / 3 times the width 50W of the absorbing element 50, or about 5 to 50 mm, particularly about 10 to 30 mm. Furthermore, as shown in the illustrated example, if there is a top sheet 30 adjacent to the surface of the absorbing element 50, and both ends of the width direction WD of the absorbing element 50 are not covered by the top sheet 30, and both ends of the width direction WD of the top sheet 30 are non-bonded regions 31 that are not bonded to the surface of the absorbing element 50, and the region between these non-bonded regions 31 is a bonded region 32 bonded to the surface of the absorbing element 50 by a hot melt adhesive HM4, then it is preferable that the first region 50A and the third region 50C extend to the same extent as the boundary between the non-bonded region 31 and the bonded region 32, or further towards the center of the width direction WD, for example, about 5 to 10 mm. In order to reduce material costs, 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, there is a high risk that the non-bonded region 31 of the top sheet 30 may peel up, allowing the user to feel the superabsorbent polymer particles, or that superabsorbent polymer particles that have escaped from the absorbent element 50 may move to the front side of the top sheet 30. In contrast, as shown in the illustrated example, if the first region 50A and the third region 50C are at the same level as the boundary between the non-bonded region 31 and the bonded region 32, or extend about 5 to 10 mm further towards the center in the width direction WD, then the entire non-bonded region 31 of the top sheet 30 overlaps with the first region 50A and the third region 50C, where the compression of the bottom 51 of the groove 53 is weaker. This is preferable because even if the skin touches the surface of the absorbent element 50, the feel of the superabsorbent polymer particles will be weaker, and the superabsorbent polymer particles will be less likely to escape.

[0079] (Packaging non-woven fabric) The packaging nonwoven fabric 58 has a meltblown layer formed of fibers with an average fiber diameter of 5 μm or less, and when five layers are stacked, the air permeability measured according to JIS L 1096:2010 using Method A (Fragile method) is 25.5 to 70.0 cm². 3 / cm 2Nonwoven fabric of type s is preferred. The breathability of five layers of packaging nonwoven fabric 58 is 40.0 to 70.0 cm. 3 / cm 2 It is more preferable that it is s. This air permeability can be measured, for example, using an air permeability meter (model AP-500KZ4) from Daiei Kagaku Seiki Seisakusho. The meltblown layer is a nonwoven fabric layer formed by accumulating ultrafine fibers obtained by spinning molten resin raw material in a high-speed hot gas flow and bonding the fibers together. The average fiber diameter of the constituent fibers is fine, at 10 μm or less, and the fiber length is long, at 30 μm or more, and the fiber spacing is also small. It is preferable that the average fiber diameter of the fibers in the meltblown layer is 2.5 μm or less. Furthermore, the average fiber diameter of the fibers in the meltblown layer can be 1 μm or more, and is preferable to be 2 μm or more.

[0080] The total basis weight (sum of the basis weights of all layers if there are multiple meltblown layers) and total thickness (sum of the thicknesses of all layers if there are multiple meltblown layers) of the meltblown layer can be determined as appropriate. For example, the total basis weight of the meltblown layer can be 0.3 to 6 g / m². 2 This allows for a total meltblown layer thickness of 0.01 to 0.35 mm.

[0081] The packaging nonwoven fabric 58 may be a single-layer nonwoven fabric consisting only of a meltblown layer, as long as it has a meltblown layer. However, a laminated nonwoven fabric having one or more meltblown layers and one or more protective layers is preferred. The laminated nonwoven fabric may be manufactured by sequentially stacking the webs constituting each layer and then bonding the fibers and each layer by thermal bonding (point bonding, hot air bonding, etc.), or by individually forming the nonwoven fabric layers constituting each layer (web formation and inter-fiber bonding), stacking them, and joining the layers thermally or with an adhesive.

[0082] A spunbond layer can be suitably used as a protective layer. As is well known, a spunbond layer is a nonwoven fabric layer formed by accumulating filaments obtained by extruding (spinning) 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 meltblown layer, and the fiber length is also longer than that of the meltblown layer. More specifically, as the packaging nonwoven fabric 58, an SMS nonwoven fabric, SSMMS nonwoven fabric, etc., in which at least one meltblown layer is sandwiched between a pair of spunbond layers on the front and back can be suitably used. The material of the constituent fibers of each layer is not particularly limited; for example, polypropylene fibers, polyethylene / polypropylene bicomponent fibers, etc. can be used in the meltblown layer, and polypropylene fibers, polyethylene / polypropylene bicomponent fibers, etc. can be used in the spunbond layer.

[0083] The fiber diameter of the constituent fibers of the protective layer, the total basis weight (sum of the basis weights of all layers if there are multiple protective layers), and the total thickness (sum of the thicknesses of all layers if there are multiple protective layers) can be determined as appropriate. 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 should be 5 to 17.5 g / m². 2 (especially 5-10g / m 2 Preferably, the total thickness of the protective layer is 0.01 to 0.35 mm (particularly 0.1 to 0.2 mm).

[0084] The basis weight and thickness of the packaging nonwoven fabric 58 can be determined as appropriate. For example, the total basis weight of the packaging nonwoven fabric 58 may be 10 to 17 g / m². 2 It is preferable that the packaging nonwoven fabric 58 has a thickness of 0.2 to 0.8 mm.

[0085] If the packaging nonwoven fabric 58 is not easily stretchable, it will not only 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 nonwoven fabric 58 has a standard elongation rate of 20-100%, particularly 30-60%, in the front-to-back direction LD as specified in JIS L 1913:2010, and a standard elongation rate of 20-110%, particularly 50-70%, in the width direction WD as specified in JIS L 1913:2010. When uniform grooves are formed using such a nonwoven fabric, the gritty feel of the superabsorbent polymer particles is easily transmitted to the user. However, as mentioned above, by making the depth d1 of the grooves 53 in the first region 50A and the third region 50C shallower than the depth d2 of the grooves 53 in the second region 50B, it is possible to improve the shape retention and flexibility of the absorbent 56 while suppressing the transmission of the gritty feel of the superabsorbent polymer particles to the user.

[0086] In particular, when using a nonwoven fabric as the packaging nonwoven fabric 58, which has one or more meltblown layers made of fibers with an average fiber diameter of 5 μm or less, and one or more protective layers made of fibers with an average fiber diameter of 10 to 25 μm, and which has the above-mentioned elongation rate, the basis weight of the packaging nonwoven fabric 58 should be 15 to 17 g / m². 2 Furthermore, adopting the aforementioned bottom 51 thickness change region is preferable because it makes it difficult for the highly absorbent polymer particles to escape to the outside of the packaging nonwoven fabric 58.

[0087] The packaging structure of the nonwoven fabric 58 can be determined as appropriate, but from the viewpoint of ease of manufacturing and preventing leakage of highly absorbent polymer particles from the front and rear edges, it is preferable to wrap it in a cylindrical shape so as to surround the front and back surfaces and both sides of the absorbent 56, as shown in the illustrated example, with the front and rear edges protruding from the front and rear of the absorbent 56, and to join the overlapping portions of the wrapped material and the protruding portions using joining means such as hot melt adhesive or material welding.

[0088] More specifically, the illustrated packaging nonwoven fabric 58 has a surface portion 58s located on the front side of the absorbent 56, a first back portion 58a extending from the surface portion 58s and wrapping around one side edge of the absorbent 56 to the back side of the absorbent 56, and a second back portion 58b extending from the surface portion 58s and wrapping around the other side edge of the absorbent 56 to the back side of the absorbent 56. The first back portion 58a and the second back portion 58b have overlapping laminated portions 58W, in which the first back portion 58a and the second back portion 58b are bonded together by a first hot melt adhesive HM1, and in the region where the packaging nonwoven fabric 58 and the absorbent 56 face each other, the inner surface of the packaging nonwoven fabric 58 and the outer surface of the absorbent 56 are bonded together by a second hot melt adhesive HM2 and a third hot melt adhesive HM3. The wrapping method of the nonwoven packaging fabric may be reversed from the illustrated example, so that the laminated portion 58W is 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 such as spiral, Z-shaped, or wavy patterns is preferably used.

[0089] To reduce the feel of the superabsorbent polymer particles in the first region 50A and the third region 50C, and to prevent the superabsorbent polymer particles from coming loose, as shown in Figure 9, it is preferable to apply the third hot melt adhesive HM3, which adheres at least the lower surface of the packaging nonwoven fabric 58 to the upper surface of the absorbent 56, in slot application (continuous film application), and to apply the second hot melt adhesive HM2, which adheres the remaining parts, intermittently. In particular, as shown in the illustrated example, it is preferable to apply the third hot melt adhesive HM3 in slot application to the region on the inner surface of the packaging nonwoven fabric 58 that extends from the back side of the absorbent 56, around the side of the absorbent 56, to the front side of the absorbent 56 in the first region 50A and the third region 50C, and wrap it around the absorbent 56. Preferably, the third hot melt adhesive HM3 is provided over the entire width WD of the first region 50A and the third region 50C, but may also be provided only on the sides of the first region 50A and the third region 50C. Furthermore, the width WD dimension of the third hot melt adhesive HM3 may differ between the front and back sides of the absorbent 56, in which case it is preferable that the front side of the absorbent 56 is wider.

[0090] As shown in Figure 13, in this structure, a second hot melt adhesive HM2 is applied to the middle of the width direction of the surface of the unfolded packaging nonwoven fabric 58 facing the absorbent 56, a third hot melt adhesive HM3 is applied adjacent to both sides in the width direction, and a first hot melt adhesive HM1 is applied to one end in the width direction. Then, the absorbent 56 is positioned so that it extends from the middle of one of the third hot melt adhesives in the width direction to the middle of the other third hot melt adhesive in the width direction of the packaging nonwoven fabric 58, and then the absorbent 56 is... After applying the second hot-melt adhesive HM2 to almost the entire surface of the opposite side, as shown in Figure 14, the portions of the packaging nonwoven fabric 58 that protrude on both sides of the absorbent 56 are folded back onto the opposite side of the absorbent 56, bonding the outer surface of the absorbent 56 and the inner surface of the packaging nonwoven fabric 58 via the second hot-melt adhesive HM2, and the overlapping portions of the packaging nonwoven fabric 58 are bonded via the first hot-melt adhesive HM1. Subsequently, as shown in Figure 9, grooves 53 are formed by embossing, thereby enabling the manufacturing process.

[0091] To reduce costs, the absorbent element 50 does not necessarily have any other sheet layer such as paper or nonwoven fabric (which may, of course, have an adhesive layer) between the packaging nonwoven fabric 58 and the absorbent body 56, as shown in Figure 9, etc., or it may have other sheet layers on at least one side of the front and back of the absorbent body 56.

[0092] (Gathered up) The rise-up gather 60 has a rise-up portion 68 that rises from the side of the inner lining 200, and this rise-up portion 68 contacts the wearer's groin, legs, and buttocks to prevent leakage from the sides. In the illustrated example, the rise-up gather 60 has the base portion 60B rising diagonally toward the center in the width direction, and the tip portion 60A rising diagonally toward the outside in the width direction from the middle portion, but it is not limited to this, and can be modified as appropriate, such as having the entire garment rising toward the center in the width direction.

[0093] More specifically, the rise-up gather 60 in the illustrated example is made by folding a strip-shaped gather sheet 62, which has a length equal to the front-to-back length of the interior body 200, in the width direction WD at the tip and overlapping it in two. Multiple elongated gather elastic members 63 are fixed between the folded portion and the sheet in the vicinity therein, extended along the longitudinal direction and spaced apart in the width direction WD. The base end of the rise-up gather 60, located opposite the tip (the end opposite the folded portion of the sheet in the width direction WD), is a root portion 65 fixed to the side of the interior body 200, and the portion other than this root portion 65 is a main body portion 66 (the portion on the folded portion side) extending from the root portion 65. The main body portion 66 has a root side portion 60B that extends towards the center in the width direction, and a tip side portion 60A that is folded back at the tip of the root side portion 60B and extends outward in the width direction. Furthermore, while both ends of the main body portion 66 in the front-rear direction are fixed to the side surface of the top sheet 30 in a collapsed state as collapsed portions 67, the middle portion in the front-rear direction located between these is an unfixed upright portion 68, and a gathered elastic member 63 is fixed in an extended state to at least the tip of this upright portion 68 along the front-rear direction LD.

[0094] In the rise-up gather 60 configured as described above, the rise-up portion 68 rises up so as to come into contact with the skin, as indicated by the arrows in Figure 3, due to the contraction force of the gather elastic member 63. In particular, if the base portion 65 is located on the back side of the inner body 200, the rise-up portion 68 stands up so as to open outward in the width direction in the crotch area and its vicinity, so that the rise-up gather 60 comes into contact with the legs over a wider surface, improving the fit. The base portion 65 can also be fixed to the front side of the inner body 200, for example, to the surfaces on both sides of the top sheet 30.

[0095] In a bending structure like the lifting gather 60 in the illustrated example, where the main body portion 66 consists of a base portion 60B extending towards the center in the width direction and a tip portion 60A that is folded back at the tip of the base portion 60B and extends outward in the width direction, the tip portion 60A and the base portion 60B are joined in a collapsed state at the collapsed portion 67, and the base portion 60B is joined to the top sheet 30 in a collapsed state. For joining the opposing surfaces at the collapsed portion 67, at least one of hot melt adhesives applied by various methods and material welding means such as heat sealing or ultrasonic sealing can be used. In this case, the joining of the base portion 60B and the top sheet 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 base portion 60B and the top sheet 30 using a hot melt adhesive, and to join the tip portion 60A and the base portion 60B by material welding.

[0096] As the gathered sheet 62, flexible, uniform, and opaque nonwoven fabrics such as spunbond nonwoven fabric (SS, SSS, etc.), SMS nonwoven fabric (SMS, SSMMS, etc.), and meltblown nonwoven fabric can be suitably used, and may be treated with a water-repellent coating such as silicone as needed. In this case, the fiber weight of the nonwoven fabric should be 10-30 g / m². 2 It is preferable to keep it to a certain extent. Although not shown in the diagram, a waterproof film can also be interposed between the two folded gathered sheets 62.

[0097] As the gathered elastic member 63, a thread elastic or the like can be used. When using spandex thread elastic, the thickness is preferably 470 to 1240 dtex, and more preferably 620 to 940 dtex. The elongation rate of the gathered elastic member 63 when attached is preferably 150 to 350%, and more preferably 200 to 300%. The number of gathered elastic members 63 is preferably 2 to 6, and more preferably 3 to 5. The spacing between the gathered elastic members 63 is appropriately 3 to 10 mm. With this configuration, the gathered elastic member 63 can easily make contact with the skin over a wider area. The gathered elastic member 63 may be placed not only at the tip but also at the base.

[0098] In the raised portion 68 of the raised gather 60, at least one of the following methods can be used to bond the inner and outer layers of the gather sheet 62 and to fix the gathered elastic member 63 sandwiched between them: hot melt adhesive applied by various methods and fixing means such as heat sealing or ultrasonic sealing. Bonding the entire inner and outer layers of the gather sheet 62 would impair flexibility, so it is preferable that the parts of the gathered elastic member 63 other than the bonded portion are not bonded or are weakly bonded. In the illustrated example, hot melt adhesive is applied only to the outer surface of the gathered elastic member 63 using an application means such as a comb gun or Surewrap nozzle, and the member is sandwiched between the inner and outer layers of the gather sheet 62. This structure ensures that the gathered elastic member 63 is fixed to the inner and outer layers of the gather sheet 62 and fixed between the inner and outer layers of the gather sheet 62 using only the hot melt adhesive applied to the outer surface of the gathered elastic member 63.

[0099] Similarly, for fixing the fallen portion 67, at least one of the following methods can be used: hot melt adhesive applied by various methods, and material welding such as heat sealing or ultrasonic sealing.

[0100] (Side flaps) As shown in Figures 1 to 4, side flaps 70 extending laterally from the absorber 56 are provided on both sides of the interior body 200, and it is preferable that a side expansion region SG that expands and contracts in the front-rear direction is formed on these side flaps 70. The side flap 70 in the illustrated example has one or more elongated side elastic members 73 provided along the front-rear direction LD and spaced apart from each other, a first sheet layer 71 facing the outside of the side elastic members 73, and a second sheet layer 72 facing the inside of the side elastic members 73.

[0101] The sheet material forming the first sheet layer 71 and the second sheet layer 72 is not particularly limited, and an appropriate nonwoven fabric can be selected, such as the nonwoven fabric that can be used in the aforementioned rise-up gather 60 or the aforementioned exterior body 12F, 12B. In the illustrated example, as will be described later, the gathered sheet 62 of the rise-up gather 60 is extended to form the first sheet layer 71 and the second sheet layer 72. In this case, the front and rear ends of the side flap 70 coincide with the front and rear ends of the rise-up gather 60 (i.e., the front and rear ends of the interior body 200 in this case).

[0102] The side elastic members 73 are not particularly limited, and elongated elastic members similar to the gathered elastic members 63 described above can be used. The elongation rate of the side elastic members 73 in the installed state is preferably 150 to 350%, and more preferably 200 to 270%. The number of side elastic members 73 is preferably 2 to 16, and more preferably 6 to 10. The spacing between the side elastic members 73 is appropriately 5 to 10 mm.

[0103] The side elastic member 73 is fixed to the first sheet layer 71 and the second sheet layer 72. Various methods of application can be used to bond the first sheet layer 71 and the second sheet layer 72, and to fix the side elastic member 73 sandwiched between them. Hot melt adhesive HM can be applied using various methods, and fixing means such as heat sealing or ultrasonic sealing can be used to weld the material. If the bonding area between the first sheet layer 71 and the second sheet layer 72 is large, flexibility will be impaired, so it is preferable that the parts of the side elastic member 73 other than the bonded parts are not bonded or are weakly bonded. In the illustrated example, hot melt adhesive HM is applied only to the outer circumferential surface of the side elastic member 73 using an application means such as a comb gun or a Surewrap nozzle, and the side elastic member 73 is sandwiched between the first sheet layer 71 and the second sheet layer 72. This structure is such that the side elastic member 73 is fixed to the first sheet layer 71 and the second sheet layer 72, and fixed between the first sheet layer 71 and the second sheet layer 72, using only the hot melt adhesive HM applied to the outer circumferential surface of the side elastic member 73.

[0104] In the illustrated example, the sheet material forming the first sheet layer 71 and the sheet material forming the second sheet layer 72 are folded back at the side edges of the side flap 70, and this folded portion is fixed (sealed) to the back surface of the liquid-impermeable sheet 11. This fixing can be done using hot-melt adhesive HM as shown in the illustrated example, or by welding the materials together.

[0105] The side flaps 70 can be omitted.

[0106] (Exterior) The outer garments 12F and 12B, as shown in the illustrated example, consist of a rectangular front outer garment 12F which constitutes at least the torso portion of the front body F, and a rectangular rear outer garment 12B which constitutes at least the torso portion of the rear body B. The front outer garment 12F and rear outer garment 12B may not be continuous at the crotch and may be separated in the front-to-back direction LD (two-part outer garment type), or they may be continuous from the front to the back (one-piece outer garment type), although this is not shown. In the two-part outer garment type, the separation distance 12d in the front-to-back direction can be, for example, about 40-60% of the total length Y. In the illustrated example, the lower edges of the front outer garment 12F and rear outer garment 12B are straight lines along the width direction WD, but at least one of the lower edges of the front outer garment 12F and rear outer garment 12B may be curved to follow the leg circumference.

[0107] In a two-part outer casing type disposable diaper, the inner casing 200 is exposed between the front outer casing 12F and the rear outer casing 12B. Therefore, to prevent the liquid-impermeable sheet 11 from being exposed on the back surface of the inner casing 200, it is preferable that the back surface of the inner casing 200 is provided with a cover nonwoven fabric 13 extending from between the front outer casing 12F and the inner casing 200 to between the rear outer casing 12B and the inner casing 200. The inner and outer surfaces of the cover nonwoven fabric 13 can be bonded to opposing surfaces via hot-melt adhesive. The nonwoven fabric used for the cover nonwoven fabric 13 can be appropriately selected from the same material as that used for the outer casings 12F and 12B. Although not shown in the figures, the outer casing may extend continuously from the front body F to the back body B, passing through the crotch area. In this case, the outer casing will have a portion corresponding not only to the waist area T but also to the intermediate area L.

[0108] The front outer casing 12F and the rear outer casing 12B have a front waist portion and a rear waist portion that constitute the waist region T. In the examples shown in Figures 1 and 2, the front outer casing 12F and the rear outer casing 12B have the same dimensions in the front-rear direction LD, and neither the front outer casing 12F nor the rear outer casing 12B has a portion corresponding to the intermediate region L. However, as shown in Figure 7, the front-rear dimension of the rear outer casing 12B is longer than that of the front outer casing 12F, and the front outer casing 12F does not have a portion corresponding to the intermediate region L, but the rear outer casing 12B may have a buttock cover portion C extending from the waist region T towards the intermediate region L. Although not shown, the front outer casing 12F may also be provided with an inguinal cover portion extending from the waist region T towards the intermediate region L.

[0109] As shown in Figures 4 and 5, the outer casings 12F and 12B are formed by joining an outer sheet layer and an inner sheet layer adjacent to the outside and inside of the elastic members 16-19, respectively, using joining means such as hot melt adhesive or welding. The outer sheet layer and the inner sheet layer can be formed from two sheet materials 12S and 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 formed in part or all of the outer casings 12F and 12B by the inner and outer portions of a single sheet material that is folded back at the edge of the waist opening WO (which may also be the edge on the crotch side). The illustrated example is the former example, where the sheet material 12S forming the outer sheet layer in the lower part of the waist wraps around the waist opening WO side of the sheet material 12H forming the inner sheet layer in the lower part of the waist and is folded back inwards, and this folded portion 12r extends to cover the end of the inner casing 200 on the waist opening WO side. On the other hand, in the waist area, the folded portion 12r is an inner sheet layer adjacent to the inside of the elastic member.

[0110] The outer casings 12F and 12B incorporate elastic members 16-19 to improve the fit around the wearer's waist, forming an elastic stretch region A2 that stretches elastically in the width direction WD as the elastic members 16-19 expand and contract. In this stretch region A2, the outer casings 12F and 12B contract as the elastic members contract in their natural length state, forming wrinkles or folds. When stretched in the longitudinal direction of the elastic members, they can be stretched to a predetermined elongation rate without wrinkles. As elastic members 16-19, in addition to elongated elastic members such as thread elastic (illustrated example), known elastic members such as strip-shaped, mesh-shaped, or film-shaped members can be used without particular limitation. Synthetic rubber or natural rubber may be used as elastic members 16-19.

[0111] To describe the elastic members 16-19 in the illustrated example in more detail, multiple waist elastic members 17 are attached to the waist portion W of the outer bodies 12F and 12B at intervals in the front-rear direction so as to be continuous throughout the width direction WD. Furthermore, one or more of the waist elastic members 17 located in the region adjacent to the lower waist portion U may overlap with the inner body 200, or they may be provided on both sides in the width direction, excluding the central portion in the width direction that overlaps with the inner body 200. The waist elastic members 17 have a thickness of 155-1880 dtex, particularly around 470-1240 dtex (in the case of synthetic rubber; in the case of natural rubber, the cross-sectional area is 0.05-1.5 mm²). 2 Especially 0.1~1.0mm 2 It is preferable to provide 2 to 15 strands, particularly 4 to 10 strands, of elastic thread (of a certain thickness) at intervals of 2 to 12 mm, especially at intervals of 3 to 7 mm, and the resulting elongation rate of the waist portion W in the width direction WD is preferably 150 to 400%, particularly 220 to 320%. Furthermore, it is not necessary to use elastic members of the same thickness or have the same elongation rate throughout the entire front-to-back direction LD of the waist portion W; for example, the thickness and elongation rate may differ in parts.

[0112] Furthermore, multiple waist-lower elastic members 16 and 19, made of elongated elastic material, are attached to the waist-lower portion U of the outer casings 12F and 12B at intervals in the front-to-back direction, forming a waist-lower expansion region (a region having waist-lower elastic members 16 and 19). The waist-lower elastic members 16 and 19 have a thickness of 155 to 1880 dtex, particularly around 470 to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, the cross-sectional area is 0.05 to 1.5 mm²). 2 Especially 0.1~1.0mm 2 It is preferable to provide about 5 to 30 strands of elastic thread (of a certain thickness) at intervals of 1 to 15 mm, particularly 3 to 8 mm, and the resulting elongation rate of the width direction WD of the lower waist U is preferably 200 to 350%, particularly 240 to 300%. Furthermore, it is not necessary to use elastic members of the same thickness or have the same elongation rate throughout the entire front-to-back direction LD of the lower waist U; the thickness and elongation rate may differ in parts.

[0113] When elastic members 16 and 19 are provided in the front-to-back range having an absorbent 56, as shown in the illustrated example below the waist U, it is preferable that, in order to prevent contraction of the absorbent 56 in the width direction WD in part or all of the area, the middle part in the width direction including part or all of the portion overlapping the absorbent 56 in the width direction WD is designated as a non-stretchable region A1, and both sides of it in the width direction are designated as stretchable regions A2 (in the illustrated example, this becomes the stretchable region below the waist). The width direction dimensions of the stretchable regions A2 provided on both sides of the width direction of the non-stretchable region A1 are made substantially constant in the front-to-back direction LD as shown in the illustrated example, or they can be changed in the front-to-back direction LD, although this is not shown. Furthermore, the width direction WD dimensions of the stretchable regions A2 provided on both sides of the width direction WD of the non-stretchable region A1 are made substantially the same for the front body F and the back body B, or they can be different.

[0114] Such an expandable region A2 and a non-expandable region A1 can be constructed by attaching elastic members 16-17,19 between the inner sheet layer and the outer sheet layer, and then finely cutting the elastic members 16,19 by pressurizing and heating or cutting at one point or almost the entire widthwise middle of the region that will become the non-expandable region A1, thereby retaining elasticity in the expandable region A2 while eliminating elasticity in the non-expandable region A1. In this way, an unnecessary elastic member 18 that does not substantially contribute to the formation of elasticity will remain in the non-expandable region A1.

[0115] The sheet materials 12S and 12H that form the inner and outer sheet layers can be used without particular limitations, but nonwoven fabric is preferred. When using nonwoven fabric, the basis weight per sheet should be 10 to 30 g / m². 2 It is preferable to keep it to a certain extent.

[0116] The elastic members 16-19 can be fixed to the outer casings 12F and 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 outer casings 12F and 12B that have elastic members 16-19, hot melt adhesive HM can be applied only to the outer circumferential surfaces of the elastic members 16-19 using an application means such as a comb gun or a Surewrap nozzle, and then sandwiched between the inner and outer sheet layers. This allows the elastic members 16-19 to be fixed to the inner and outer sheet layers, as well as the inner and outer sheet layers, using only the hot melt adhesive HM applied to the outer circumferential surfaces of the elastic members 16-19.

[0117] (Internal body joint) The interior body 200 can be joined to the exterior bodies 12F and 12B by joining means such as material welding, like heat sealing or ultrasonic sealing, or by using a hot melt adhesive. In the illustrated example, the interior body 200 is fixed to the inner surfaces of the exterior bodies 12F and 12B via a hot melt adhesive applied to the back surface of the interior body 200, that is, in this case, the back surface of the liquid-impermeable sheet 11 and the base portion 65 of the rising gather 60. As shown in Figure 2, the interior body joining portion 201 that joins the interior body 200 and the exterior bodies 12F and 12B can be provided over almost the entire area where the two overlap, and can also be provided in portions excluding both ends in the width direction of the interior body 200, for example.

[0118] As described above, since it is possible to suppress the leakage of superabsorbent polymer particles through the packaging nonwoven fabric 58, it is possible to omit components such as the top sheet 30 and intermediate sheet 40 that cover the surface of the absorbent element 50, and in that case, a significant cost reduction can be achieved. In this case, as long as the intermediate portion of the surface of the absorbent element 50, excluding both ends in the width direction WD, is not covered by other components over the entire length LD in the front-to-back direction, and the packaging nonwoven fabric 58 is exposed on the surface, it is not necessary for only the intermediate portion in the width direction WD to be covered by other components, or for the entire surface of the absorbent element 50 to be not covered by other components.

[0119] <Effectiveness Confirmation Test> Three types of disposable pant-type diapers, 1 to 4, were prepared, each with the structure shown in Figures 1 to 12. In Sample 1, the second hot-melt adhesive HM2 and the third hot-melt adhesive HM3, which bond the packaging nonwoven fabric 58 and the absorbent material 56, were applied in a spiral pattern, and the ratio of pulp fibers to superabsorbent polymer particles was uniformly set at 40:60 in the first region 50A, the second region 50B, and the third region 50C, while the thickness of the absorbent material 56 in the first region 50A and the third region 50C was made thinner than in the second region 50B. Sample 2 was identical to Sample 1 except that the third hot-melt adhesive HM3 was applied in a slotted pattern. Sample 3 was identical to Sample 1 except for changes to the ratio of pulp fibers to superabsorbent polymer particles, the basis weight of pulp fibers in the first region 50A and the third region 50C, the basis weight of superabsorbent polymer particles, the groove depth d1, and the basis weight of superabsorbent polymer particles in the second region 50B. Sample 4 was identical to Sample 1 except for the same basis weight of pulp fibers in the first region 50A and the third region 50C, the basis weight of superabsorbent polymer particles, the ratio of pulp fibers to superabsorbent polymer particles, and the thickness of the absorbent material 56 as in the second region 50B, and the increased depth d1 of the grooves 53 in the first region 50A and the third region 50C. Other specifications are as shown in Table 1. In addition, specifications other than those shown in Table 1 were common to all samples.

[0120] For samples A to C, the surface of the bottom 51 of the grooves 53 in the first region 50A and the third region 50C was lightly traced with a finger, and the presence or absence of a gritty texture from the superabsorbent polymer particles was evaluated in two stages: ○ (not felt or only a few particles felt) or × (gritty texture felt). In addition, the superabsorbent polymer particle detachment confirmation test described below was performed on these samples A to C.

[0121] (Test to confirm the escape of superabsorbent polymer particles) As a pretreatment, each sample was turned inside out and folded in half so that the top sheet 30 was exposed on the outside. Then, the front outer casing 12F and the rear outer casing 12B were cut along the front-to-back direction LD between both side seals 12A and both side edges of the inner casing 200. As shown in Figure 20, the waist portion W of the front outer casing 12F and the center of the waist portion W in the width direction WD of the rear outer casing 12B of the pretreated sample 100 were overlapped and secured by clamping them with the sample holder (clip) 300 of the Hardy Integrity Tester - Disposable Diaper Testing Machine / Model No:130729. At this time, in order to capture the superabsorbent polymer particles that escape from the sample 100 with a bag, a polypropylene recovery bag 301, which is wider and taller than the sample 100, was placed over the outside of the sample 100 and secured together with the sample 100 by clamping them with the sample holder 300. The Hardy Integrity Tester was set to move vertically 10 mm, rotate at 1200 r / min, and reciprocate 500 times, and sample 100 was moved up and down. Afterwards, the number of superabsorbent polymer particles that escaped into the collection bag 301 was counted.

[0122] The test results are shown in Table 1. Sample 4 had a gritty texture and some superabsorbent polymer particles escaped, whereas Samples 1-3, despite having a continuous grid of grooves, did not have a gritty texture and no superabsorbent polymer particles escaped.

[0123] [Table 1]

[0124] <Explanation of terms used in the specification> The following terms in this specification shall have the meanings set forth below, unless otherwise specified in this specification.

[0125] "Front-to-back direction" refers to the direction indicated by the symbol LD in the diagram (vertical direction), and "width direction" refers to the direction indicated by WD in the diagram (left-to-right direction). The front-to-back direction and the width direction are orthogonal to each other.

[0126] "Front side" refers to the side that is closer to the wearer's skin when worn, while "back side" refers to the side that is further away from the wearer's skin when worn.

[0127] "Front side" refers to the side that is closer to the wearer's skin when worn, while "back side" refers to the side that is further away from the wearer's skin when worn.

[0128] • "Elongation rate" refers to the value relative to the natural length, which is set at 100%. For example, an elongation rate of 200% is equivalent to an elongation ratio of 2.

[0129] "Artificial urine" is a mixture of urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt%, and deionized water: 97.09 wt%.

[0130] The "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).

[0131] The "average fiber diameter" is determined by observing the target layer at a magnification of 1000x using a microscope (optical microscope or SEM, etc.), randomly selecting 30 constituent fibers, measuring their fiber diameter (μm), and calculating the average value.

[0132] "Weight" is measured as follows: After pre-drying the sample or test piece, leave it in a test room or apparatus under standard conditions (temperature 23±1°C, relative humidity 50±2%) to reach a constant weight. Pre-drying means bringing the sample or test piece to a constant weight in an environment of 100°C. Note that pre-drying is not necessary for fibers with an official moisture content of 0.0%. Using a sample-taking template (100mm x 100mm), cut out a sample measuring 100mm x 100mm from the test piece that has reached a constant weight. Measure the weight of the sample, multiply it by 100 to calculate the weight per square meter, and this is the weight.

[0133] The "thickness" of thick components such as the absorber 56 and absorbent element 50 is measured using a thickness measuring instrument (Peacock, dial thickness gauge, model JB (measurement range 0-35 mm, circular terminal with a measurement area diameter of 20 mm, measuring force approximately 3.0 N, pressure approximately 30 KPa)) manufactured by Ozaki Seisakusho Co., Ltd., with the sample and the thickness measuring instrument held horizontally.

[0134] The "thickness" of the bottom 51 of the groove 53 is determined by subtracting the depth of the groove 53 from the thickness of the absorption element 50 (uncompressible portion 52).

[0135] The "depth" of groove 53 is measured using a one-shot 3D measuring machine manufactured by Keyence Corporation. stomachMeasurements are performed using a microscope VR-3200 or equivalent, the observation application "VR-H2V," and the analysis application "VR-H2A," or equivalent software. As a general rule, the magnification for measurement is 12x and the field of view is 24mm x 18mm, but 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, the sample is placed on the microscope stage so that the groove 53 to be measured is 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 explained below with reference to Figure 19. That is, using the analysis application, the depth (measured cross-sectional curve) profile of the groove 53 in the image area (XY portion in the figure) shown in a planar view is obtained along the orthogonal line segment Q1 that intersects the part of the groove 53 other than the intersection. From the cross-sectional curve of this depth profile, the surface roughness component with wavelengths shorter than λc:800μm (where λc is the "filter that defines the boundary between the roughness component and the waviness component" as described in JIS-B0601 "3.1.1.2") is removed by a low-pass filter. In the "contour curve Q2" of the image portion (XZ portion in the figure) shown in the cross-sectional view obtained, the positions where the curvature becomes almost flat or where the curvature is strongest and convex upwards are designated as two boundary points P1 and P2, and the minimum height value 51L of the range enclosed by these boundary points P1 and P2 is determined. Furthermore, the average of the height values ​​of boundary points P1 and P2 is taken as the maximum height. Then, the depth of the groove 53 can be determined by subtracting the minimum height value 51L from the maximum height. The two boundary points P1 and P2 are selected visually. When selecting them, the planar view image of the groove 53 during the measurement may be used as a reference. The above measurements are performed at any 10 locations other than the intersections of grooves designed to have the same dimensions and shape, and the results are taken as the average value.

[0136] The "thickness" of thin sheets such as nonwoven fabrics is measured using an automatic thickness measuring instrument (KES-G5 handy compression measurement program) with a load of 0.098 N / cm². 2 , and pressure area: 2cm 2The measurement is performed automatically under these conditions. Note that the "thickness" of the packaging nonwoven fabric refers to the thickness of the portion where the thickness of the absorbent element 50 is 50t, which is the maximum value.

[0137] The "thickness of the layer" of a nonwoven fabric is determined by observing the cross-section of the target layer at the point where the thickness of the absorption element 50 (50t) is at its maximum using a microscope (optical microscope or SEM, etc.) at a magnification of 1000x, randomly selecting five measurement points to measure the apparent thickness, and calculating the average value.

[0138] • "Area ratio" refers to the ratio of the area of ​​the target part per unit area, and is expressed as a percentage by dividing the total area of ​​the target part (e.g., the bottom 51 of the groove 53) within the entire target area (e.g., the back surface of the absorbent element 50) by the area of ​​the target area. When determining the area ratio of the bottom 51 of the groove 53, a rectangular area of ​​any area containing one or more unit frames is brought into view, and the area of ​​the bottom 51 of the groove 53 is determined as described later.

[0139] • The "area" of the bottom 51 of groove 53 is measured using a one-shot 3D measuring machine manufactured by Keyence Corporation. stomachMeasurements are performed using a microscope VR-3200 or equivalent, the observation application "VR-H2V," and the analysis application "VR-H2A," or equivalent software. As a general rule, the magnification for measurement is 12x and the field of view is 24mm x 18mm, but the magnification and field of view can be changed depending on the size of the groove 53. Specifically, when measuring the area, start the observation application, place the sample on the microscope stage so that the groove 53 to be measured is within the field of view, and press the "Measure" button. Next, run the analysis application and press the "Volume / Area" button to move to the volume / area measurement screen in order to analyze the measured 3D information. On the volume / area measurement screen, press the "Recess" button, then the "Set Measurement Area" button, then press the "Minimum Height" button from "Auxiliary Tools 2" to specify an area that includes the groove 53, and select the lowest point within the displayed area. Next, select "Automatic Extraction (Level)" from "Element Tools," specify the lowest point as the reference point, set the crossover height to +0.25mm, and press the "OK" button. Return to the volume / area measurement screen, and the value displayed as the area of ​​the portion from the lowest point within the specified area up to a height of 0.25 mm will be taken as the area of ​​the bottom 51 of the groove 53 in the field of view.

[0140] • Water absorption is measured according to JIS K7223-1996 "Test method for water absorption of superabsorbent polymers".

[0141] The water absorption rate shall be the "time to the endpoint" when 2 g of superabsorbent polymer and 50 g of physiological saline solution are used in the test according to JIS K7224-1996 "Test method for water absorption rate of superabsorbent polymers".

[0142] "Deployed state" refers to a state in which the body is unfolded flat without any contraction (including contraction due to elastic members, etc.) or slack.

[0143] Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not the natural length state.

[0144] Unless otherwise specified, the tests and measurements shall be conducted in a test room or apparatus under standard conditions (temperature 23±1°C, relative humidity 50±2%). [Industrial applicability]

[0145] This invention can be used for disposable diapers such as pant-type disposable diapers, tape-type disposable diapers, and pad-type disposable diapers, as well as for absorbent articles in general, such as sanitary napkins. [Explanation of Symbols]

[0146] 11...Liquid-impermeable sheet, 12A...Side seal, 12B...Rear outer casing, 12E...Waist extension, 12F,12B...Outer casing, 12F...Front outer casing, 12S,12H...Sheet material, 13...Cover nonwoven fabric, 16,19...Waist lower elastic member, 17...Waist elastic member, 18...Unnecessary elastic member, 200...Inner casing, 201...Inner casing joint, 30...Top sheet, 40...Intermediate sheet, 50...Absorbing element, 51...Bottom, 51f...Unit frame, 52...Uncompressible part, 53...Groove, 56...Absorbing material, 56L...Low basis weight part, 58...Packaging nonwoven fabric, 60...Upright gather, 60A...Tip side part, 60B...Base side part, 62...Gathered sheet, 63...Gathered elastic member, 67...Folded part Minutes, 68...rising part, 70...side flap, 71...first sheet layer, 72...second sheet layer, 73...side elastic member, 90...anvil roll, 91...protrusion, 92...smooth roll, A1...non-stretch area, A2...stretch area, B...back body, C...buttocks cover part, F...front body, HM...hot melt adhesive, HM1...first hot melt adhesive, HM2...second hot melt adhesive, HM3...third hot melt adhesive, L...intermediate area, LD...front-back direction, LO...leg opening, M...crotch area, SG...side stretch area, T...waist area, U...lower waist part, W...waist part, WD...width direction, WO...waist opening, 50A...first area, 50B...second area, 50C...third area.

Claims

1. The garment has a crotch portion and a front portion and a rear portion extending forward and rearward from the crotch portion, an absorbent element having an absorbent body provided at a position including the crotch area and a wrapping nonwoven fabric wrapping the absorbent body; The absorbent body has a layer formed by mixing and accumulating pulp fibers and highly absorbent polymer particles, When the absorbent element is divided into three regions in the width direction, namely, a first region, a second region, and a third region, grooves having bottoms recessed from the surface of the absorbent element to the absorbent body and compressed in the thickness direction are provided in a lattice pattern in the first region and the third region located on both sides in the width direction and in the second region located in the middle in the width direction, and a depth of the groove in the first region and the third region is shallower than a depth of the groove in the second region; An absorbent article characterized by:

2. The basis weight of the pulp fiber in the absorbent body is 100 to 450 g / m ２ and the weight ratio of pulp fibers to 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 thickness of said base is 10 to 30% of the maximum thickness of said absorbent element; The depth of the grooves in the first region and the third region is 0.6 to 0.85 times the depth of the grooves in the second region. The absorbent article of claim 1.

3. The width of the bottom is 1 to 3 mm; The grooves are continuous in a lattice pattern. The absorbent article according to claim 2.

4. The packaging nonwoven fabric has one or more meltblown layers and one or more protective layers, The weight of the packaging nonwoven fabric is 10 to 17 g / m ２ and The constituent fibers of the protective layer have an average fiber diameter of 10 to 25 μm, The constituent fibers of the meltblown layer are fibers having an average fiber diameter of 5 μm or less, The air permeability measured in accordance with JIS L 1096:2010 using Method A (Fragile method) in a state where five sheets of the packaging nonwoven fabric are stacked is 25.5 to 70.0 cm ３ / cm ２ s, The packaging nonwoven fabric has a standard elongation rate in the front-rear direction, as defined in JIS L 1913:2010, of 20 to 100%, The standard elongation in the width direction as defined in JIS L 1913:2010 is 20 to 110%. The absorbent article according to any one of claims 1 to 3.

5. The basis weight of the absorbent body in the first region and the third region is 0.65 to 0.85 times the basis weight of the absorbent body in the second region. The absorbent article according to any one of claims 1 to 3.

6. a topsheet adjacent to a surface of the absorbent element; Both ends of the absorbent element in the width direction are not covered by the top sheet, both ends of the top sheet in the width direction are non-bonded regions that are not bonded to the surface of the absorbent element, and the region between these non-bonded regions is an adhesive region that is bonded to the surface of the absorbent element by a hot melt adhesive, The first region and the third region extend to the same extent as the boundary between the non-bonded region and the bonded region or to the center side in the width direction. The absorbent article according to any one of claims 1 to 3.

7. A hot melt adhesive is provided to bond the inner surface of the packaging nonwoven fabric and the outer surface of the absorbent body, In the first region and the third region, a hot melt adhesive is slot-applied to bond at least the lower surface of the packaging nonwoven fabric and the upper surface of the absorbent body, In the second region, a hot melt adhesive is intermittently applied to bond at least the lower surface of the packaging nonwoven fabric and the upper surface of the absorbent body. The absorbent article according to any one of claims 1 to 3.

8. the basis weight of the superabsorbent polymer particles in the first region and the third region is less than the basis weight of the superabsorbent polymer particles in the second region; The absorbent article according to any one of claims 1 to 3.

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