Disposable diaper

Abstract

To provide a disposable diaper which can improve maintaining properties of a urine reception space and tracking deformation properties, in a crotch of a wearer.SOLUTION: A disposable diaper is configured so that: an absorber 56 has a pair of slender slits 56L extending in a cross direction LD provided on one side and the other side in a width direction WD in a crotch M, and has a center region 56C defined as a clearance between the one slit 56L and the other slit 56L, and a pair of side regions 56S defined as a clearance between a side edge of the absorber 56 and the slits 56L on both sides in the width direction WD. In the center region 56C and the side region 56S, grooves 53 having bottoms 51 recessed into the absorber 56 from any one of a front surface and a rear surface of the absorber 56 and compressed in a thickness direction are provided at a pattern continuous in the width direction WD in a range of the cross direction LD of 60% or more of the center region and the side region, the center region 56C has a constant thickness of the bottom 51 of the groove 53 and has a low area ratio of the bottom 51 of the groove 53, as compared with the side region 56S.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] This invention relates to a disposable diaper that improves the maintenance of the urine receiving space (the gap between the surface of the crotch area of ​​the disposable diaper and the skin) and improves its conformability and deformation in the groin area. [Background technology]

[0002] In disposable diapers, it is common to use an absorbent material made by mixing and accumulating pulp fibers and superabsorbent polymer particles. To improve shape retention during and after manufacturing, such an absorbent material is typically incorporated as an absorbent element wrapped in a packaging sheet made of crepe paper or the like (see, for example, Patent Document 1).

[0003] The absorbent element of a disposable diaper is sandwiched between the legs and subjected to forces from various directions on both sides in the width direction due to leg movements such as walking. Therefore, it is required to have conforming deformability that can deform to follow the width of the crotch, while also having shape retention properties that maintain a desirable fit. Of course, the absorbent element of a disposable diaper is also required to ensure sufficient absorption in the crotch area.

[0004] For example, in a typical disposable diaper, the crotch area forms a roughly U-shaped cross-section when worn, with the middle of the crotch area forming the bottom and both sides rising up to form side walls. As a result, a urine-receiving space is formed between the surface of the crotch area of ​​the disposable diaper and the skin, making it less likely to leak even when a large amount of urine is urinated at once.

[0005] To facilitate deformation into a roughly U-shaped cross-section, it has been conventional to form a pair of slits that penetrate in the thickness direction along the front-to-back direction on both sides in the width direction of the absorbent material in the crotch area. In this case, the absorbent material becomes easier to bend at the slits, and the center region between the pair of slits forms the bottom, while the side regions to the sides of each slit rise up to form the side walls. This not only makes it easier for the crotch area of ​​the diaper to take on a roughly U-shaped cross-section, but the rigidity of the side walls, which contain the absorbent material, is also increased (i.e., the urine receiving space is less likely to collapse), and the absorbent function is also enhanced. However, this function is lost or drastically reduced when the superabsorbent polymer particles expand due to urine absorption, reducing the shape retention of the absorbent material, and the slits collapse.

[0006] As a method to improve the shape retention of an absorbent material, it is known to provide grooves with a bottom portion compressed in the thickness direction in a grid-like or other pattern (see, for example, Patent Document 1). However, since providing grooves by compression leads to increased rigidity, if grooves are provided by compression in a uniformly dense pattern throughout the entire absorbent material, considering shape retention after urine absorption, the bottom portion becomes less likely to bend when the crotch area deforms into a roughly U-shaped cross-section, and it becomes less likely to deform to follow the width of the crotch (reduced conforming deformability). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-000236 [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, the main objectives of the present invention are to improve the maintenance of the urine-receiving space and the conforming deformation of the groin area. [Means for solving the problem]

[0009] The following disposable diapers solve the above problems. <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 over a range in the front-to-back direction including the crotch area, and a packaging sheet that encloses the absorbent body. The absorbent material is made by mixing and accumulating pulp fibers and superabsorbent polymer particles. The absorbent body has a pair of elongated slits extending in the front-to-back direction, provided on one and the other sides in the width direction of the crotch area, The absorbent has a center region defined as the space between one slit and the other slit, and a pair of side regions defined as the space between the slit and the side edge of the absorbent on both sides in the width direction. The center region and the side region are provided with grooves extending over 60% or more of their lengthwise direction, each groove having a bottom that is recessed from at least one of the front and back surfaces of the absorbent into the absorbent body and compressed in the thickness direction, in a continuous pattern in the width direction. The center region, compared to the side region, has either a constant thickness at the bottom of the groove and a low area ratio at the bottom of the groove, or a constant area ratio at the bottom of the groove and a thicker thickness at the bottom of the groove, or a low area ratio at the bottom of the groove and a thicker thickness at the bottom of the groove. Disposable diapers characterized by the following features.

[0010] (Effects and Benefits) This disposable diaper offers improved maintenance and conformability of the urine-receiving space in the groin area for the following reasons: (a) The absorbent material becomes more flexible at the slits, with the center region forming the bottom and each side region rising up to form the side walls. This not only makes the crotch area of ​​the diaper more likely to have a roughly U-shaped cross-section, but also increases the rigidity of the side walls (i.e., the urine receiving space is less likely to collapse), and provides an absorbent function. (i) In both the center and side regions, grooves are provided in a predetermined pattern that extend from at least one of the front and back surfaces of the absorbent element into the absorbent body and have a bottom that is compressed in the thickness direction. Therefore, compared to cases where this is not the case, the absorbent body is more likely to maintain its shape after absorbing urine. (c) Furthermore, while possessing the advantages of (a) and (b) above, the center region is relatively flexible and the side regions are relatively shape-retaining, so when the crotch area of ​​the diaper is worn in a U-shaped cross-section, the side walls become more rigid, making the urine-receiving space less likely to collapse, while the bottom part becomes more flexible and more easily deforms to conform to the width of the crotch.

[0011] <Second aspect> The center region and the side region are regions in which the grooves are continuous in a grid pattern, The thickness and width of the bottom of the groove are the same in the center region and the side region, The maximum area of ​​the unit frame consisting of the grooves in the center region is 1.5 to 4 times the maximum area of ​​the unit frame consisting of the grooves in the side region. A disposable diaper of the first type.

[0012] (Effects and Benefits) When grooves having a bottom that is recessed from the surface of the absorber into the absorber and compressed in the thickness direction are provided in the absorber in a pattern that is continuous in a lattice shape, at least the bottoms of the grooves that are highly dense and highly rigid are continuous in at least the width direction, so that the region having the grooves has particularly high shape retention, at least in the width direction. There is also an advantage that the liquid diffusibility in the direction along the grooves is improved. Here, although the shape retention changes depending on the thickness of the bottom of the groove of the absorber, the range of the change is not large. Also, when the width of the bottom of the groove is increased, the feel of the hard bottom of the groove is likely to be transmitted to the skin. Therefore, as in this embodiment, it is preferable to make the area of the unit frame formed by the grooves different in the center region and the side region while making the thickness of the bottom of the groove and the width of the bottom of the groove the same. As a result, not only is the shape retention improved, but the liquid diffusibility in the side region is higher than that in the center region, and lateral leakage is less likely to occur.

[0013] <The third aspect> The absorber is composed of one or more layers formed by mixing and integrating pulp fibers and superabsorbent polymer particles. The basis weight of the pulp fibers in the absorber is 80 to 450 g / m 2 and the ratio of pulp fibers to superabsorbent polymer particles in the absorber is 20:80 to 80:20 by weight. The maximum value of the thickness of the absorber is 1 to 20 mm. The thickness of the bottom is 5 to 40% of the maximum value of the thickness of the absorber. the law of nature and the width of the bottom is 1 to 3 mm. The area of the unit frame formed by the grooves in the center region is 150 to 500 mm 2 and The disposable diaper of the second aspect.

[0014] (Function and effect) The dimensions of the grooves can be determined as appropriate, but in the absorber as in this embodiment, it is preferable to form the grooves within the range of this embodiment.

[0015] <The fourth aspect> The groove is formed in an oblique grid pattern, consisting of a first portion inclined 40 to 60° clockwise in a plan view with respect to the front-rear direction, and a second portion inclined 40 to 60° counterclockwise in a plan view with respect to the front-rear direction. Disposable diapers of the second or third form.

[0016] (Effects and Benefits) The groove pattern can be determined as appropriate, but a diagonal grid pattern as in this embodiment is preferred.

[0017] <Fifth aspect> The widthwise dimension of the unit frame in the side region is 0.5 times or less the minimum widthwise dimension of the side region. A disposable diaper in any one of the second to fourth forms.

[0018] (Effects and Benefits) With the configuration described in this embodiment, at least one unit frame exists in the side region, and even if the position of the grid pattern is slightly shifted due to manufacturing tolerances, this configuration is particularly favorable in terms of both improved rigidity and improved diffusivity.

[0019] <Sixth aspect> The groove pattern in both side regions consists only of a slit-adjacent frame consisting of the side edge of the slit and the groove, a side-edge-adjacent frame consisting of the side edge of the absorber and the groove, and a complete unit frame having the same dimensions and shape. The area of ​​each slit-adjacent frame and the area of ​​each side-edge-adjacent frame in both of the aforementioned side regions are smaller than the area of ​​the unit frame. A disposable diaper of the fifth type.

[0020] (Effects and Benefits) This configuration is preferable because, when the diaper has a roughly U-shaped cross-section, the rigidity of both side walls becomes particularly high, making it less likely for the urine receiving space to collapse.

[0021] <Seventh aspect> The two side edges of the absorbent extend linearly along the front-to-back direction, The pair of slits extend from the middle in the front-rear direction toward the front and rear sides, respectively, approaching the side edges of the absorber. Disposable diapers in any one of the 1st to 6th embodiments

[0022] (Effects and Benefits) With the slit shaped as in this embodiment, the center region forms the bottom and each side region rises to form the side wall, resulting in a roughly U-shaped cross-section for the crotch area of ​​the diaper. Not only does this allow the side wall to fit easily to the inside of the thigh joint, but the height of the side wall decreases towards both the front and back, making it less likely to fold, so the urine receiving space is particularly less likely to collapse in that vicinity. [Effects of the Invention]

[0023] According to the present invention, it is possible to improve the maintenance of the urinary reception space and the conforming deformation of the groin area. [Brief explanation of the drawing]

[0024] [Figure 1] This is a plan view showing the surface of a pull-up type disposable diaper in its unfolded state. [Figure 2] This is a plan view showing the back of a pull-up type disposable diaper in its unfolded state. [Figure 3] This is a cross-sectional view of section 3-3 in Figure 1. [Figure 4] This is a cross-sectional view of section 4-4 in Figure 1. [Figure 5] This is a cross-sectional view of section 5-5 in Figure 1. [Figure 6] This is a plan view showing the surface of the interior lining. [Figure 7] This is a perspective view of a pull-up type disposable diaper, seen from the front and slightly below. [Figure 8] This is a cross-sectional view of the main part showing the installed state. [Figure 9] This is a cross-sectional view of the absorption element. [Figure 10] A plan view of the absorber. [Figure 11] This is a plan view showing an enlarged view of the main part of Figure 10. [Figure 12] A plan view of the absorber. [Figure 13] A plan view of the absorber. [Figure 14] This is a plan view of the absorber in its unfolded state, showing an example of a slit. [Modes for carrying out the invention]

[0025] The disposable diapers described above will be explained in detail below, referring to the example of a pant-type disposable diaper shown in the attached drawing. Note that adjacent components in the thickness direction are 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 application, continuous linear or dotted bead application, spiral, Z-shaped, or wavy (regular or irregular) spray application, 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.

[0026] 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.

[0027] Figures 1 to 7 show an example of a pant-type disposable diaper. This pant-type disposable diaper 100 comprises a rectangular front outer body 12F that constitutes the front waist area FT and a rectangular rear outer body 12B that constitutes the rear waist area BT, and an inner body 200 that is joined to the front outer body 12F and 12B in the width direction WD 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 edges of the outer bodies 12F and 12B become a waist opening WO through which the wearer's torso 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 WD become leg openings LO through which the legs pass. The inner lining 200 is the part that absorbs and retains excrement such as urine, and the outer linings 12F and 12B are the parts that support the inner lining 200 against the wearer's body. The symbol Y indicates the total length of the diaper in the unfolded state (the length in the front-to-back direction from the edge of the waist opening WO of the front panel F to the edge of the waist opening WO of the back panel B), and the symbol X indicates the total width of the diaper in the unfolded state.

[0028] The disposable pant-type diaper 100 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 portion forming 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 portions of the front outer body 12F and the back outer body 12B located in the waist area T, that is, the front waist portion FT and the back waist portion BT, can be conceptually distinguished into a "waist portion" W that forms the edge of the waist opening and a "lower waist portion" U which is the portion below the waist portion. Typically, if there is a boundary within the front waist circumference FT and rear waist circumference BT where the stretch stress in the width direction WD changes (for example, the thickness or elongation rate of the elastic member changes), the waist portion W extends beyond the boundary closest to the waist opening WO. If there is no such boundary, the waist portion W extends beyond the absorbent material 56 or inner lining 200 toward the waist opening WO. These lengths in the front-to-back direction vary depending on the size of the product and can be determined as appropriate. For example, the waist portion W can be 15-40 mm, and the lower waist portion 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 follow the circumference of 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.

[0029] (Fixed area of ​​interior components) The interior body 200 can be fixed to the exterior bodies 12F and 12B by joining means such as material welding, like heat sealing or ultrasonic sealing, or by hot melt adhesive HM3. In the illustrated example, the back surface of the interior body 200 is fixed to the inner surfaces of the exterior bodies 12F and 12B via hot melt adhesive HM3. In the illustrated example, the fixing area 201 of the interior body 200 is provided in the area where the front fuselage section FT and the rear fuselage section BT overlap with the interior body 200. Preferably, the fixing area of ​​the interior body extends substantially over the entire area, excluding the periphery of the area where the exterior bodies 12F and 12B overlap with the interior body 200.

[0030] (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 front torso section FT (the torso section of the front body F) and a rectangular rear outer garment 12B which constitutes at least the rear torso section BT (the torso section 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 body F through the crotch section M to the rear body B (one-piece outer garment type). 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.

[0031] 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 layer 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 layer 13 can be bonded to opposing surfaces via a second hot melt adhesive HM2 and a third hot melt adhesive HM3, respectively. The nonwoven fabric used for the cover nonwoven fabric layer 13 can be appropriately selected from the same material as that used for the outer casings 12F and 12B.

[0032] In the examples shown in Figures 1 and 2, the rear exterior body 12B is longer in the front-to-rear direction than the front exterior body 12F, the front exterior body 12F does not have a portion corresponding to the intermediate region L, and the rear exterior body 12B has a buttock cover portion 14 that extends from the torso region T towards the intermediate region L. However, the dimensions of the front exterior body 12F and the rear exterior body 12B in the front-to-rear direction LD are equal, and the front exterior body 12F and the rear exterior body 12B do not necessarily have portions corresponding to the intermediate region L.

[0033] As shown in Figures 3 to 5, the outer casings 12F and 12B are formed by joining the outer sheet layer 12S and inner sheet layer 12H adjacent to the outside and inside of the elastic members 15 to 17, respectively, using joining means such as hot melt adhesive or welding. The outer sheet layer 12S and inner sheet layer 12H are formed by folding a single sheet material so that the fold is located on the waist opening side, as shown in Figure 5, or, although not shown, by bonding two sheet materials together.

[0034] The sheet material used for the outer sheet layer 12S and the inner sheet layer 12H can be any material without particular limitations, but nonwoven fabric is preferred. When using nonwoven fabric, the basis weight per sheet should be 8 to 20 g / m². 2 It is preferable to keep it to a certain extent.

[0035] In the outer casings 12F and 12B, elastic members 15 to 17 are attached between the outer sheet layer 12S and the inner sheet layer 12H at a predetermined elongation rate to improve the fit around the wearer's waist, forming an expandable region that elastically expands and contracts in the width direction WD together with the elastic members 15 to 17. The expandable region can expand and contract between a natural length state in which wrinkles or folds are formed when it is contracted together with the elastic members 15 to 17, and an expanded state in which it is stretched in the width direction to a predetermined elongation rate that is completely wrinkle-free together with the elastic members 15 to 17. As elastic members 15 to 17, 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 15 to 17. For bonding the outer sheet layer 12S and the inner sheet layer 12H of the exterior bodies 12F and 12B, and for fixing the elongated elastic members 15-17 sandwiched between them, at least one of hot-melt adhesives applied by various methods and fixing means such as heat sealing or ultrasonic sealing can be used. Since firmly fixing the entire surface of the exterior bodies 12F and 12B would impair flexibility, it is preferable that the parts of the elongated elastic members 15-17 other than the bonded parts are not bonded or are weakly bonded. In the illustrated example, hot-melt adhesive is applied only to the outer circumferential surfaces of the elongated elastic members 15-17 using an application means such as a comb gun or Surewrap nozzle, and they are sandwiched between the two sheet layers 12S and 12H. This structure ensures that the elongated elastic members 15-17 are fixed to the two sheet layers 12S and 12H, and that the two sheet layers 12S and 12H are fixed together using only the hot-melt adhesive applied to the outer circumferential surfaces of the elongated elastic members 15-17.

[0036] To describe the elastic members 15-17 in the illustrated example in more detail, a plurality of waist elastic members 17 are attached between the outer sheet layer 12S and the inner sheet layer 12H in the waist portion W of the outer bodies 12F and 12B, spaced apart in the front-rear direction and stretched along the width direction at a predetermined elongation rate, thereby forming a continuous waist stretching region over the entire width direction WD. .MaFurthermore, of the waist elastic members 17, one or more members arranged in the region adjacent to the lower waist portion U may overlap with the interior body 200, or they may be provided on both sides of the width direction WD, excluding the central portion in the width direction that overlaps with the interior body 200. The waist elastic members 17 have a thickness of 300 to 940 dtex, particularly about 470 to 780 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 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 300%, particularly 200 to 280%. 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.

[0037] Furthermore, multiple waist-lower elastic members 15, made of elongated elastic material, are attached between the outer sheet layer 12S and the inner sheet layer 12H in the waist-lower portion U of the outer bodies 12F and 12B, spaced apart in the front-to-back direction and stretched along the width direction at a predetermined elongation rate. This forms waist-lower stretchable regions on both sides of the width direction WD, excluding the width-direction center portion that overlaps with the inner body 200. The waist-lower elastic members 15 have a thickness of 300 to 940 dtex, particularly around 470 to 780 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.

[0038] Further, between the outer seat layer 12S and the inner seat layer 12H in the hip cover portion 14 of the rear exterior body 12B, one or more hip cover elastic members 16 made of elongated elastic members are attached at intervals in the vertical direction and in a state of being stretched along the width direction WD at a predetermined elongation rate on both sides of the width direction WD excluding the central portion in the width direction that overlaps with the interior body 200, and hip cover expansion and contraction regions are formed on both sides of the width direction WD excluding the central portion in the width direction that overlaps with the interior body 200. As the hip cover elastic member 16, yarn rubber having a thickness of 300 to 940 dtex, particularly about 470 to 780 dtex (in the case of synthetic rubber. In the case of natural rubber, the cross-sectional area is 0.05 to 1.5 mm 2 , particularly about 0.1 to 1.0 mm 2 degree) is preferably fixed at intervals of 5 to 40 mm, particularly 5 to 20 mm, in about 2 to 10 strands, each at an elongation rate of 150 to 300%, particularly 180 to 260%.

[0039] Among the front torso surrounding portion FT and the rear torso surrounding portion BT, the first region consisting of the portion overlapping with the absorber 56 and the portion between this and the side seal 12A is an intermittent stretchable band A1 having a non-stretchable region 12X provided at least in the middle portion in the width direction WD in the portion overlapping with the absorber 56 and stretchable regions provided between each of the non-stretchable region 12X and the side seal 12A, and the second region located between this intermittent stretchable band A1 and the waist opening WO is preferably a continuous stretchable band A2 in which the stretchable region is continuous in the width direction WD from one side seal 12A to the other side seal 12A.

[0040] In the illustrated example, the intermittent expansion band A1 may extend beyond the range of the first region (beyond the absorber 56) to the waist opening WO side, as long as it includes the first region. In the illustrated example, in the rear waist section BT, only the first region is the intermittent expansion band A1, and the area between the first region and the waist opening WO is the continuous expansion band A2, and in the front waist section FT, the area consisting of the part overlapping with the fixed region 201 of the inner lining 200 and the part between this and the side seal 12A (the area extending further towards the waist opening WO side than the first region) is the intermittent expansion band A1, but it is not limited to this. Therefore, these may be reversed, and in both the front waist section FT and the rear waist section BT, the area consisting of the part overlapping with the fixed region 201 of the inner lining 200 and the part between this and the side seal 12A may be the intermittent expansion band A1, or in both the front waist section FT and the rear waist section BT, only the first region may be the intermittent expansion band A1. Furthermore, although the intermittent stretchable band A1 in the illustrated example is formed in a range LD in the front-rear direction that includes only the stretchable area below the waist having the waist elastic member 15, the range may be expanded toward the waist opening WO to include a part of the stretchable area below the waist having the waist elastic member 17.

[0041] In the illustrated example, the continuous stretchable band A2 is formed only by a waist stretchable region having a waist elastic member 17 in the front waist circumference FT, and by the entire waist stretchable region having a waist elastic member 17 and a part of the lower waist stretchable region including a lower waist elastic member 15 in the rear waist circumference BT, but it is not limited to these. Therefore, these may be reversed, and the continuous stretchable band A2 in both the front waist circumference FT and the rear waist circumference BT may be formed only by a waist stretchable region having a waist elastic member 17, or by the entire waist stretchable region having a waist elastic member 17 and a part of the lower waist stretchable region having a lower waist elastic member 15.

[0042] As shown in the figure, if the first region consisting of the portion overlapping with the absorber 56 and the portion between it and the side seal 12A is an intermittent expandable band A1 rather than a continuous expandable band A2, the absorber 56 will not contract excessively in the width direction WD, preventing a decrease in fit, a bulky and unsightly appearance, or a decrease in absorbency. Such an intermittent expandable band A1 includes cases where elastic members 15 and 16 are present only on both sides in the width direction WD, as well as cases where elastic members 15 and 16 are present across the absorber 56 from one side to the other in the width direction WD, but the middle or entire widthwise portion of the overlapping part with the absorber 56 is a non-stretchable region 12X where the contraction force hardly acts (essentially equivalent to not having elastic members 15 and 16) due to the elastic members 15 and 16 being finely cut, while both sides in the width direction WD are expandable regions (parts where contraction force acts). The non-stretchable region 12X is preferably located between the side edges of the interior body 200, and more preferably between the side edges of the absorber 56. The width WD dimension of the non-stretchable region 12X can be determined as appropriate, but is preferably 0.6 to 1.2 times the maximum width of the absorber 56, and more preferably 0.8 to 1.0 times. Furthermore, the width WD dimension of the non-stretchable region 12X is preferably 0.5 to 1.0 times the width WD dimension of the continuous stretchable band A2, and more preferably 0.6 to 0.8 times.

[0043] (Interior structure) The shape of the inner lining 200 is arbitrary, but in the illustrated example it is rectangular. As shown in Figures 3 to 5, the inner lining 200 comprises a liquid-permeable top sheet 30 that faces the wearer's skin, a liquid-impermeable sheet 11, and an absorbent element 50 interposed between them. Reference numeral 60 indicates a side flap 60 having a flat gather.

[0044] (Top sheet) The top sheet 30 can be made of any liquid-permeable material, such as a perforated or non-perforated nonwoven fabric or a perforated plastic sheet, without any particular limitations. However, as shown in the examples in Figures 3 and 4, if the top sheet 30 also serves as a covering material for the liquid-impermeable sheet layer 64, a nonwoven fabric is preferred for the top sheet 30.

[0045] The sides of the top sheet 30 may be folded back to the back of the absorption element 50 at the side edges of the absorption element 50, or they may be left unfolded and protrude laterally beyond the side edges of the absorption element 50. If necessary, the overall width of the top sheet 30 may be made shorter than the overall width of the absorption element 50, so that the side edges of the top sheet 30 are positioned on the absorption element 50.

[0046] (Intermediate sheet) Although not shown in the diagram, an intermediate sheet (also called a "second sheet") 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. This intermediate sheet is intended to quickly transfer the liquid to the absorbent, enhance the absorption performance of the absorbent, and prevent the "backflow" phenomenon of the absorbed liquid from the absorbent. The intermediate sheet can also be omitted.

[0047] (Liquid-impermeable sheet) The material of the liquid-impermeable sheet 11 provided on the back side of the absorbent 56 is not particularly limited, but examples include plastic films made of polyolefin resins such as polyethylene and polypropylene. It is preferable to use a material that is both liquid-impermeable and moisture-permeable for the liquid-impermeable sheet 11, which has been favored in recent years from the viewpoint of preventing stuffiness. As a moisture-permeable 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.

[0048] The liquid-impermeable sheet 11 can be configured to extend into the side flaps to improve the waterproofness of the flat gathers, as shown in the examples in Figures 3 and 4, or it can be made to have a width that fits on the back side of the absorbent element 50 (not shown), or it can be folded back to the front side at the side edge of the absorbent element 50 and extended between the absorbent element 50 and the top sheet 30.

[0049] (Absorption element) As shown in Figures 3, 4, and 9, the absorbent element 50 includes an absorbent body 56 and a packaging sheet 58 that encloses the entire absorbent body 56. The packaging sheet 58 may be omitted.

[0050] (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, 80 to 450 g / m². 2 Approximately, more preferably 80-200 g / m² 2 It can be considered to be of a certain degree.

[0051] Superabsorbent polymer particles are mixed into the fiber aggregate. 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.

[0052] 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 (JIS K7223-1996 "Test Method for Water Absorption of Superabsorbent Resins") 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. The shape of the superabsorbent polymer particles is preferably the commonly used granular form, but other shapes can also be used.

[0053] As superabsorbent polymer particles, those with a water absorption rate of 70 seconds or less, and particularly 40 seconds or less, are preferably used. If the water absorption rate is too slow, the liquid supplied into the absorbent material 56 is likely to flow back out of the absorbent material 56, a phenomenon known as backflow.

[0054] Furthermore, as the superabsorbent polymer particles, those with a gel strength of 1000 Pa or more are preferably used. This effectively suppresses the sticky feeling after liquid absorption, even when a bulky absorbent material 56 is used.

[0055] The basis weight of the superabsorbent polymer particles can be appropriately determined according to the amount of absorption required for the application of the absorbent material 56. Therefore, it is not possible to say definitively, but it is generally between 50 and 350 g / m². 2 This can be achieved. The basis weight of the polymer is 50 g / m². 2 Below 350g / m², it becomes difficult to ensure sufficient absorption. 2 Beyond a certain point, the effect saturates.

[0056] The ratio of fibers to superabsorbent polymer particles in the absorbent body 56 is not particularly limited. For example, the weight ratio of pulp fibers to superabsorbent polymer particles can be 20:80 to 80:20, more preferably 40:60 to 60:40. In particular, when the weight ratio of pulp fibers to superabsorbent polymer particles is 40:60 to 60:40, a thinner absorbent body 56 can be made when comparing the same area and the same absorption capacity. The thickness 56t of the absorbent body 56 is not particularly limited, but can be 1 to 20 mm, more preferably 2 to 5 mm.

[0057] The absorbent material 56 is provided over a range LD in the front-to-back direction, including the crotch area M. Preferably, the absorbent material 56 extends from the front waist area FT to the rear waist area BT. Preferably, the portion of the absorbent material 56 located in the fixing area 201 of the inner body 200 is fixed to the outer body 12F, 12B via a packaging sheet 58, a liquid-impermeable sheet 11, a hot-melt adhesive HM3, etc. Reference numeral 56X indicates the maximum width (total width) of the absorbent material 56.

[0058] The absorbent body 56 is preferably roughly rectangular in shape, as shown in the illustrated example, because it makes it easier to ensure sufficient absorption in the crotch area M. However, it may also have a constricted portion in the crotch area M (that is, the absorbent body 56 has a minimum width portion located midway along the front-to-back direction LD, and widening portions that gradually increase in width from this minimum width portion to the maximum width portion in front of the crotch area M, and from the maximum width portion behind the crotch area M).

[0059] The crotch area M refers to the area LD in the front-to-back direction that has the slit described later, with the front and rear portions extending forward and backward from this area, respectively.

[0060] (slit) The absorbent material 56 has a pair of elongated slits 56L extending in the front-to-back direction LD on one side and the other side in the width direction WD of the crotch area M. By providing such slits 56L in the absorbent material 56, as shown in Figure 8, the flexion of the absorbent material 56 along the slits 56L is promoted when worn, causing the crotch area M of the diaper to deform into a roughly U-shaped cross-section. That is, the center region 56C, which is determined as the space between one slit 56L and the other slit 56L, forms the bottom, and the pair of side regions 56S, which are determined as the space between the slits 56L on both sides in the width direction WD and the side edges 56e of the absorbent material 56, rise up to form side walls, so that the crotch area M of the diaper has a roughly U-shaped cross-section. The center region 56C and the pair of side regions 56S are shown as a dot pattern in Figure 14.

[0061] As long as the slit 56L is elongated and extends in the front-rear direction LD, it may extend linearly along the front-rear direction LD as shown in Figure 14(b), or it may extend in a way that approaches the side edge of the absorber 56 as it moves from the middle of the front-rear direction LD toward the front and rear, respectively, as shown in Figure 14(a), etc. At least one of the front and rear ends of the slit 56L may be spaced apart from the side edge of the absorber 56, as shown in Figures 14(a) and (b), or one or both ends of the front or rear may reach the side edge of the absorber 56, as shown in Figures 14(c) and (d). The front and rear ends of the slit 56L can also be shaped appropriately. For example, they may be straight as shown in the example in Figure 14(d), curved (e.g., semi-circular) as shown in the example in Figure 14(a), etc., or the corners at both ends may be rounded and the middle part straight, although these are not shown. The width m1 of the slit 56L can be determined as appropriate, for example, it can be 4 to 12 mm. The width m1 of the slit 56L may be constant in its longitudinal direction or may vary. The dimensions and arrangement of the front-to-back LD of the slit 56L can be determined as appropriate. For example, the dimension m2 of the front-to-back LD of the slit 56L (equal to the dimension of the front-to-back LD of the crotch area M) can be 200 to 600%, more preferably 300 to 500%, of the minimum distance CW between both slits 56L.

[0062] (Packaging sheet) When using the packaging sheet 58, the material can be a liquid-permeable material such as tissue paper, especially crepe paper, nonwoven fabric, poly-laminated nonwoven fabric, or a sheet with small holes. However, it is desirable that the sheet does not allow the superabsorbent polymer particles to escape. When using nonwoven fabric instead of crepe paper, a hydrophilic nonwoven fabric having a dense layer is preferred. Such a nonwoven fabric may consist of one or more meltblown layers and one or more layers protecting them. vinegar Laminated nonwoven fabrics (including SMS nonwoven fabrics, SSMMS nonwoven fabrics, etc.) with a protective layer such as a Panbond layer laminated together are particularly preferred, and the material can be polypropylene, polyethylene / polypropylene composite material, etc. The basis weight of the packaging sheet 58 is, for example, 5 to 40 g / m². 2Preferably 8-20 g / m 2 It can be done this way.

[0063] The packaging structure of the packaging sheet 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 that the packaging sheet 58 is wrapped around the front, back and both sides of the absorbent body 56 in a cylindrical shape. The packaging sheet 58 may extend beyond the front and rear edges of the absorbent body, or, as shown in the illustrated example, the front and rear edges of the packaging sheet 58 may substantially coincide with the front and rear edges of the absorbent body.

[0064] (Side flaps) The inner lining 200 preferably has side flaps 60, as shown in Figures 1 to 4, 7 and 8. The side flaps 60 are a pair of portions extending from the side edge of the absorbent 56 to both sides in the width direction WD, and each extends in the front-to-back direction LD from the area overlapping with the waist elasticity region of the front body F (in the illustrated example, the area having the lower waist elastic member 15) to the area overlapping with the waist elasticity region of the back body B (in the illustrated example, the area having the lower waist elastic member 15). The side flaps 60 also have a side nonwoven fabric 66 extending from the surface of the side flap 60 through the side edge of the side flap 60 to the back surface of the side flap 60, and elongated gathered elastic members 631 to 633 provided along the front-to-back direction LD between the surface portion 61 and the back portion 62. The surface portion 61 and the back portion 62 extend over the entire front-to-back direction LD of the side flap 60. In the illustrated example, the surface portion 61 is formed by the folded portion 66r of the side nonwoven fabric 66, but is not limited to this. The front and rear ends of the side flap 60 do not contract in the front-to-back direction LD together with the gathered elastic members 631-633, and the surface portion 61 has a fixing portion 67 fixed to the back portion 62, forming a side non-stretchable region 70. The portion of the side flap 60 between the front and rear side non-stretchable regions 70 is a planar gathered region 80 to which the gathered elastic members 631-633 are fixed, which contracts in the front-to-back direction LD together with the gathered elastic members 631-633, and which can also be stretched in the front-to-back direction LD together with the gathered elastic members 631-633. This pant-type disposable diaper does not have three-dimensional gathers that rise up on the outer side, and only has planar gathers on the side flap 60. In the illustrated example of the fixing portion 67, the surface portion 61 is indirectly fixed to the back portion 62 via a liquid-impermeable sheet layer 64. However, if other members such as the liquid-impermeable sheet layer 64 are not interposed, it will be fixed directly.

[0065] The dimensions of the front-rear LD of the side non-expandable region 70 may differ at the front and rear ends of the side flap 60, as shown in the illustrated example, or they may be the same. In the figure, reference numeral 60w indicates the widthwise WD dimension of the side flap 60. Reference numeral w1 indicates the widthwise WD distance (first distance) between the fixing portion 67 and the side edge of the side non-expandable region 70, reference numeral w2 indicates the widthwise WD dimension (second distance) of the portions on both sides of the interior body (side flaps) that are not fixed to the exterior body 12, reference numeral w3 indicates the widthwise WD dimension of the fixing portion 67, reference numeral w4 indicates the widthwise WD distance (third distance) between the fixing portion 67 and the side edge of the absorber 56, and reference numeral w5 indicates the widthwise WD distance (fourth distance) between the fixing portion 67 and the central edge of the widthwise WD of the surface portion 61.

[0066] As the gathered elastic members 631 to 633, elongated elastic members such as thread-like rubber or strip-like rubber can be used. When thread-like rubber is used, the thickness of the gathered elastic members 631 to 633 is preferably 400 to 950 dtex, and more preferably 470 to 780 dtex. In addition, the elongation rate of the gathered elastic members 631 to 633 is preferably 200 to 320%, and more preferably 240 to 320%. In the figure, reference numeral 631 indicates the first gathered elastic member located first from the absorber 56 side, reference numeral 632 indicates the second gathered elastic member located second, and reference numeral 633 indicates the third or later gathered elastic member. Furthermore, the symbol d1 indicates the distance in the width direction WD between the side edge of the widest portion of the absorber 56 and the first gathered elastic member 631 (first distance), the symbol d2 indicates the distance in the width direction WD between the first gathered elastic member 631 and the second gathered elastic member 632 (second distance), and the symbol d3 indicates the distance in the width direction WD between the second gathered elastic member 632 and the third gathered elastic member 633 and the distance in the width direction WD between adjacent third gathered elastic members 633 (third distance).

[0067] In the side flap 60, at least one of hot melt adhesives applied by various methods and fixing means such as heat sealing or ultrasonic sealing can be used to bond adjacent layers in the thickness direction and to fix the gathered elastic members 631-633 sandwiched between them. Since bonding the entire surface of the layers adjacent to the front and back sides of the gathered elastic members 631-633 would impair flexibility, it is preferable that the parts of the gathered elastic members 631-633 other than the bonded parts are not bonded or are weakly bonded. In the illustrated example, hot melt adhesive is applied only to the outer circumferential surface of the gathered elastic members 631-633 using an application means such as a comb gun or Surewrap nozzle, and they are sandwiched between the layers adjacent to their front and back sides. This structure allows the gathered elastic members 631-633 to be fixed to the layers adjacent to their front and back sides, and to the layers adjacent to the front and back sides of the gathered elastic members 631-633, using only the hot melt adhesive applied to the outer circumferential surface of the gathered elastic members 631-633. If there are edges of the nonwoven fabric or sheet that are separated from the gathered elastic members 631-633, such as the edges of the top sheet 30 in the illustrated example, a separate hot melt adhesive (first hot melt adhesive HM1 in the illustrated example) can be applied to fix them in place.

[0068] As the side nonwoven fabric 66, flexible, uniform, and opaque nonwoven fabrics such as spunbond nonwoven fabrics (SS, SSS, etc.), SMS nonwoven fabrics (SMS, SSMMS, etc.), and meltblown nonwoven fabrics, which have been treated with a water-repellent coating such as silicone as needed, can be suitably used, and the fiber basis weight should be 10-30 g / m². 2 It is preferable to have a degree of difference. As can be seen from the example shown in Figures 3 and 4, where the surface nonwoven fabric layer on the base end side of the nonwoven fabric-free portion 65 is formed by the top sheet 30, it is possible to partially differ the materials of the surface nonwoven fabric layer and the back nonwoven fabric layer, and it is also possible to differ the materials of the surface nonwoven fabric layer and the back nonwoven fabric layer.

[0069] (groove) Preferably, the absorbent 56 is provided with a groove 53 having a bottom 51 that is recessed from the surface of the absorbent 56 into the absorbent 56 and compressed in the thickness direction, as shown in Figures 9 to 11. The bottom 51 of the groove 53 is a high-density portion that has been compressed by pressing (direct pressure) and whose thickness is approximately equal. Hereinafter, the portion other than the bottom 51 will be referred to as the uncompressible portion 52. The uncompressible portion 52 is a portion that is thicker and lower in density than the bottom 51, but even in the uncompressible portion 52, near the periphery of the bottom 51, the absorbent 56 deforms as if being pulled by the compression formation of the bottom 51, and as a result, the density increases as it approaches the bottom 51. As long as the uncompressible portion 52 is thicker and lower in density than the bottom 51, the entire portion may be compressed in the thickness direction at the same time as, before, or after the compression process that forms the bottom 51. The shape and arrangement of the uncompressible portion 52 are determined according to the shape and arrangement of the bottom 51.

[0070] The grooves 53 of the absorbent body 56 may be formed by embossing the absorbent body 56 alone, either with or without heating. Alternatively, they may be formed including the absorbent body 56 and other laminated members by embossing the absorbent body 56 together with other laminated members, such as the absorbent element 50 (i.e., together with the packaging sheet 58) or the inner body 200.

[0071] If the aforementioned grooves 53 are provided in a continuous pattern in the width direction WD over a range of 60% or more in the front-to-back direction LD in the center region 56C and the side region 56S, the compressed bottom portion 51 will be high density and highly rigid, thereby improving the shape retention of the center region 56C and the side region 56S. However, since providing a compressed bottom portion 51 leads to increased rigidity, if the bottom portion 51 is compressed in a uniformly dense pattern over the center region 56C and the side region 56S, taking into consideration shape retention after urine absorption, the portion located at the bottom (center region 56C) will be less likely to bend when the crotch area M is deformed into a roughly U-shaped cross-section, and will be less likely to deform in accordance with the width of the crotch (reduced conforming deformability). Therefore, it is preferable that the thickness of the bottom portion 51 of the grooves 53 is constant and the area ratio of the bottom portion 51 of the grooves 53 is lower in the center region 56C compared to the side region 56S. Alternatively, although not shown in the figures, the center region 56C may have a constant area ratio of the bottom 51 of the groove 53 and a thicker thickness of the bottom 51 of the groove 53 compared to the side region 56S, or it may have a lower area ratio of the bottom 51 of the groove 53 and a thicker thickness of the bottom 51 of the groove 53. By changing at least one of the area ratio of the bottom 51 of the groove 53 and the thickness of the bottom 51 in this way, the rigidity of the center region 56C in the groin area M is lowered compared to the side region 56S, and for the following reasons, both the maintenance and conforming deformation of the urine receiving space SP in the groin area are improved, as shown in Figure 8. (a) The absorbent material 56 becomes more easily bent at the slit 56L, the center region 56C forms the bottom, and each side region 56S rises up to form the side wall, which not only makes the crotch area M of the diaper more likely to have a roughly U-shaped cross-section, but also increases the rigidity of the side wall (i.e., the urine receiving space SP is less likely to collapse), and also provides an absorbent function. (i) Both the center region 56C and the side region 56S are provided with grooves 53 in a predetermined pattern, which are recessed from at least one of the front and back surfaces of the absorbent element 50 into the absorbent body 56 and have a bottom portion 51 that is compressed in the thickness direction. Therefore, compared to cases where this is not the case, the absorbent body 56 is more likely to maintain its shape after absorbing urine. (c) Furthermore, while possessing the advantages of (a) and (b) above, the center region 56C is relatively flexible and the side region 56S is relatively shape-retaining, so when the crotch area M of the diaper is worn in a U-shaped cross-section, the side walls become more rigid, making the urine receiving space SP less likely to collapse, while the bottom part becomes more flexible and more easily deforms to conform to the width of the crotch.

[0072] The grooves 53 described above may be formed over 80% or more of the longitudinal LD ​​range, as long as they are provided in a pattern that is continuous in the width direction WD over 60% or more of the longitudinal LD ​​range of the center region 56C and side region 56S, or they may be formed over the entire longitudinal LD ​​as shown in the illustrated example, or they may be formed only over 60% to less than 100% of the longitudinal LD ​​range from the front or rear end of the center region 56C and side region 56S, or they may not be formed at the front and rear ends of the center region 56C and side region 56S, but only in the intermediate part between them. In particular, it is preferable that the pattern of the grooves 53 continues uniformly over the entire longitudinal LD ​​range from in front of the front end of the center region 56C and side region 56S to behind the rear end of the center region 56C and side region 56S (the entire longitudinal LD ​​of the absorber 56 in the illustrated example), as this eliminates the need to position the grooves 53 in the longitudinal LD ​​and simplifies manufacturing. However, the region including more than 60% of the longitudinal LD ​​range of the center region 56C and the side region 56S may have grooves 53 with different patterns from the other regions.

[0073] The dimensions and number of the bottom portions 51 of the grooves 53 can be determined as appropriate, but the depth 51h of the bottom portions 51 (thickness 56t of the absorbent body 56 - thickness 51t of the bottom portion of the groove) is preferably 0.5 to 5 mm, and the area ratio of the bottom portions 51 of the grooves 53 (the ratio of the area of ​​the bottom portions 51 to the surface of the absorbent element 50) is preferably 20 to 40%.

[0074] The grooves 53 having a bottom portion 51 can be arranged in a grid-like continuous pattern as shown in Figures 10 and 11, as long as they are continuous in the width direction WD, or, although not shown, multiple grooves 53 along the width direction WD can be provided at intervals in the front-to-back direction LD (horizontal stripe pattern), multiple grooves 53 along the diagonal direction can be provided at intervals in a direction perpendicular to the continuous direction of the grooves 53 (diagonal stripe pattern), multiple grooves 53 extending in a wavy line can be provided at intervals in the front-to-back direction LD, or they can be arranged in other geometric patterns, or in a continuous pattern based on motifs such as letters, animals, or plants. Thus, the uncompressible portion 52 is arranged intermittently at least in the front-to-back direction LD. In particular, if the grooves 53 are arranged in a grid-like continuous pattern, the pulp fibers and superabsorbent polymer particles constituting the absorber 56 are constrained within a unit frame 54 (minimum frame) consisting of the bottom portion 51 compressed in the thickness direction, which helps to reduce twisting and cracking of the absorber 56.

[0075] The width 51w of the bottom 51 of the groove 53 can be determined as appropriate, but it is usually preferable to have a width of about 1 to 3 mm.

[0076] The thickness 51t of the bottom 51 of the groove 53 can be determined as appropriate, but it is usually preferably 5 to 40%, particularly 5 to 30%, of the maximum thickness 50t of the absorption element 50.

[0077] When grooves 53 are arranged in a grid pattern, the shape of the unit frame 54 is not particularly limited, and in addition to a roughly square as shown in the illustrated example, it can also be a roughly diamond shape (excluding squares). )、 Almost rectangular , omitted Other polygonal shapes, such as triangles, may also be used. Furthermore, as long as the bottom of the groove 51 is arranged in a grid pattern, it may include unit frames 54 of different shapes.

[0078] One preferred grid pattern of the groove 53 is a diagonal grid pattern consisting of a first portion 51a extending in a direction inclined 40 to 60° (more preferably 45 to 50°) clockwise with respect to the front-rear direction LD in a plan view, and a second portion 51b extending in a direction inclined 40 to 60° (more preferably 45 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 54 is approximately rhombic. It is particularly preferable that the angle of the first portion 51a and the second portion 51b with respect to the front-rear direction LD be 45 degrees.

[0079] The dimensions of the unit frame 54 can be determined as appropriate, but if it is too large, the effect of improving rigidity will be poor, and if it is too small, it will become too rigid. Therefore, in the usual case, the width dimension WD of the unit frame 54, 54x, is preferably about 15 to 20 mm. Also, the front-to-back dimension LD of the unit frame 54, 54y, is preferably about 15 to 20 mm.

[0080] When changing the area ratio of the bottom 51 of the groove 53, the width of the bottom 51 of the groove 53 can be changed while keeping the groove pattern 53 approximately constant, the groove pattern 53 can be changed while keeping the width 51w of the bottom 51 of the groove 53 approximately constant, or both the groove pattern 53 and the width 51w of the bottom 51 of the groove 53 can be changed. However, if the width 51w of the bottom 51 of the groove 53 is increased in order to increase the area ratio of the bottom 51 of the groove 53, the feel of the hard bottom 51 of the groove 53 will be more easily transmitted to the skin. Therefore, as shown in the illustrated example, it is preferable to change the groove pattern 53 (specifically, the number of grooves 53 per unit area) while keeping the width 51w of the bottom 51 of the groove 53 approximately constant. Furthermore, when the thickness of the bottom 51 of the groove 53 is changed in the width direction WD of the absorber 56, the range of change in the shape retention of the absorber 56 is not large, the impact on absorption performance such as liquid diffusion is large, and the ease of manufacturing is also reduced. Therefore, it is possible to change the thickness of the bottom 51 of the groove 53 while keeping the area ratio of the bottom 51 of the groove 53 approximately constant, but it is preferable to change the area ratio of the bottom 51 of the groove 53 while keeping the thickness of the bottom 51 of the groove 53 approximately constant.

[0081] Figures 10 to 13 show some preferred examples of groove patterns. In these examples, the width 51w and thickness of the bottom 51 of the groove 53 are approximately constant, while the groove pattern 53 changes in the width direction WD such that the area ratio of the bottom 51 of the groove 53 is larger in the side region 56S than in the center region 56C.

[0082] When the groove pattern 53 is grid-like, as shown in Figures 10, 11, and 12, by combining multiple shapes of unit frames 54 to create a pattern in which the area of ​​the unit frames 54 gradually decreases from the center of the width direction WD towards both edges, the area ratio of the bottom 51 of the groove 53 in the side region 56S can be made higher than that of the center region 56C. Also, as shown in Figure 13, by combining unit frames 54 of the same shape (the illustrated example is rhombus (square)) but of different sizes, a pattern can be created in which the area of ​​the unit frames 54 gradually decreases from the center of the width direction WD towards both edges, thereby making the area ratio of the bottom 51 of the groove 53 in the side region 56S higher than that of the center region 56C.

[0083] The size of the area of ​​each unit frame 54 can be determined as appropriate, but it is preferable that the area of ​​the larger unit frame 54 is 1.1 to 2.5 times the area of ​​the smaller unit frame 54 among a pair of unit frames 54 adjacent in the width direction WD with a common side. Furthermore, it is preferable that the maximum area of ​​the unit frame 54 consisting of grooves 53 in the center region 56C is 1.5 to 4 times the maximum area of ​​the unit frame 54 consisting of grooves 53 in the side region 56S. In this case, the area of ​​the unit frame 54 consisting of grooves 53 in the center region 56C is 150 to 500 mm². 2 It would be preferable if this were the case.

[0084] More specifically, the groove pattern in the example shown in Figures 10 and 11 is a diagonal grid. This pattern consists of a group of first rhombus-shaped unit frames 54a, which have the largest area, arranged without gaps in the center of the width direction WD and continuing in the front-to-back direction LD. Along the side edges of this group of first unit frames 54a, there are groups of rectangular second unit frames 54b, which share one side with the first unit frames 54a and whose short side intersecting the common side is 2 / 3 of the length of the common side, and L-shaped third unit frames 54c, which share two sides with the first unit frames 54a and whose short side intersecting the common side is 2 / 3 of the length of the common side, arranged without gaps and continuing in the front-to-back direction LD. Along the side edges of this group of second unit frames 54b and third unit frames 54c, there are groups of rhombus-shaped fourth unit frames 54d, whose side length is 2 / 3 of the length of one side of the first unit frame 54a, arranged without gaps and continuing in the front-to-back direction LD. In this case, the area of ​​the unit frame 54 of the groove 53 is 4 / 9 of the maximum area, which is a smaller change compared to the two examples described later. However, from the viewpoint of ease of manufacturing, this change is preferable.

[0085] Furthermore, the pattern of the groove 53 in the example shown in Figure 12 is also a diagonal grid. In this pattern, the first rhombus-shaped unit frame 54e, which has the largest area, is arranged without gaps in the center in the width direction WD and continues in the front-to-back direction LD, forming a group, and along the side edge of this group of first unit frames 54e, the length of one side of the first unit frame 54e is Length of one side A group is formed by arranging two rhombic second unit frames 54f, which are 1 / 2 the size of the first unit frame 54e, and an L-shaped third unit frame 54g, whose two long sides are the same length as one side of the first unit frame 54e, and whose four short sides are 1 / 2 the length of one side of the first unit frame 54e, without any gaps, and continuing in the front-to-back direction LD. Along the side edge of the group of third unit frames 54g, a group is formed by arranging two rhombic second unit frames 54f, whose side length is 1 / 2 the length of one side of the first unit frame 54e, without any gaps, and continuing in the front-to-back direction LD. In this case, the area of ​​the unit frames 54e~g is 1 / 4 of the maximum area.

[0086] Furthermore, the groove pattern 53 in the example shown in Figure 13 is also a diagonal grid. In this pattern, the first rhombus-shaped unit frame 54h, which has the largest area, is arranged without gaps in the center in the width direction WD and continues in the front-to-back direction LD, forming a group, and along the side edge of this group of first unit frames 54h, the length of one side of the first unit frame 54h is Length of one side The second rhombus-shaped unit frame 54i, which is 1 / 2 in size, are arranged without gaps to form a group that continues in the front-to-back direction LD, and along the side edge of this group of second unit frames 54i, the length of one side is the same as that of the first unit frame 54h. Length of one side This is a group of rhombic third unit frames 54j, each 1 / 3 in size, arranged without gaps, continuing in the front-to-back direction LD. In this case, the area of ​​the unit frames 54h~j is 1 / 9 of the maximum area, with a minimum area of ​​1.

[0087] When the groove pattern 53 is grid-like, as shown in the example in Figure 10, if the widthwise WD dimension of the unit frame 54 in the side region 56S is 0.5 times or less, preferably 0.3 to 0.5 times, the side region 56S will have at least one unit frame 54, which is particularly preferable in terms of both improved rigidity and improved diffusivity, even if the position of the grid pattern is slightly shifted due to manufacturing tolerances.

[0088] In this case, as shown in the example in Figure 10, the groove pattern 53 in both side regions 56S consists only of a slit-adjacent frame 54m made up of the side edge of the slit 56L and the groove 53, a side edge-adjacent frame 54n made up of the side edge 56e of the absorbent material 56 and the groove 53, and a complete (non-missing) unit frame 54 having the same dimensions and shape. It is preferable that the area of ​​each slit-adjacent frame 54m and each side edge-adjacent frame 54n is smaller than the area of ​​the unit frame 54, as this increases the rigidity of the side walls when the diaper has a roughly U-shaped cross-section, making it less likely for the urine-receiving space SP to collapse.

[0089] Of course, in the side region 56S, the area of ​​some or all of the slit-adjacent frames 54m (and the same applies to the side edge-adjacent frames 54n) may be larger than the area of ​​the unit frame 54, as shown in the examples in Figure 12 and Figure 13.

[0090] On the other hand, the groove pattern 53 in the center region 56C preferably has a complete (non-missing) unit frame 54 having the same dimensions and shape, as shown in the illustrated example. In this case, as shown in the illustrated example, there may be a slit-adjacent frame 54m consisting of the side edge of the slit 56L and the groove 53.

[0091] Although not shown in the diagram, by aligning the direction and position of the side edge of the slit 56L with the direction and position of the groove 53, the pattern of at least one of the grooves 53 in the side region 56S and the center region 56C can be made into a pattern consisting only of complete (non-missing) unit frames 54.

[0092] On the other hand, while the shape of the absorbent body 56 and the shape of the slit 56L are as described above, as shown in Figure 14(a), both side edges of the absorbent body 56 extend linearly along the anterior-posterior direction LD, and the pair of slits 56L extend from the middle of the anterior-posterior direction LD toward the front and rear, respectively, approaching the side edge 56e of the absorbent body 56. This has the advantage that when the crotch area M of the diaper has a roughly U-shaped cross-section, the side walls fit easily to the inside of the thigh joint, and the height of the side walls decreases toward both the anterior and rear sides, making them less likely to fold, so that the urine receiving space SP is particularly less likely to collapse in that vicinity.

[0093] <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.

[0094] "Front-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-right direction). The front-back direction and the width direction are orthogonal to each other.

[0095] "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.

[0096] "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.

[0097] • "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.

[0098] The "gel strength" is measured as follows: 49.0 g of artificial urine (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%) is mixed with 1.0 g of superabsorbent polymer and stirred with a stirrer. The resulting gel is left in a constant temperature and humidity chamber at 40°C × 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).

[0099] "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.

[0100] The "thickness" of thick components such as the absorber 56, absorbent element 50, and groove bottom 51 is measured using a thickness measuring instrument (Peacock, dial thickness gauge, model H (measurement range 0-10 mm, measurement area diameter 10 mm circular terminal, measuring force approximately 1.7 N, pressure approximately 21.7 KPa)) manufactured by Ozaki Seisakusho Co., Ltd., with the sample and thickness measuring instrument held horizontally.

[0101] 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 2 Automatic measurement is performed under these conditions.

[0102] • Water absorption is measured according to JIS K7223-1996 "Test method for water absorption of superabsorbent polymers".

[0103] 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 JIS K7224-1996 "Test method for water absorption rate of superabsorbent polymers".

[0104] "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.

[0105] "Maximum elongation" refers to the maximum value of elongation in the stretching direction within the stretching region (i.e., elongation at the elastic limit, which is equal to the elongation in the unfolded state), and is expressed as a percentage of the length in the unfolded state, with the natural length being 100%.

[0106] Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not the natural length state.

[0107] 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]

[0108] The present invention can be used for all types of disposable diapers, including not only the pant-type disposable diapers described above, but also tape-type disposable diapers, pad-type disposable diapers, and so on. [Explanation of symbols]

[0109] 11...Liquid-impermeable sheet, 12A...Side seal, 12B...Rear outer casing, 12F...Front outer casing, 12H...Inner sheet layer, 12S...Outer sheet layer, 12X...Non-stretchable area, 13...Cover nonwoven fabric layer, 14...Buttocks cover section, 15...Waist lower elastic member, 16...Buttocks cover elastic member, 17...Waist elastic member, 200...Inner casing, 201...Fixed area, 30...Top sheet, 50...Absorbing element 51...Bottom, 52...Uncompressed section, 53...Groove, 54...Unit frame, 54m...Slit adjacent frame, 54n...Side edge adjacent frame, 56...Absorbent, 56C...Center area, 56L...Slit, 56S...Side area, 58...Packaging sheet, 60...Side flap, 61...Surface section, 62...Back section, 631~633...Gathered elastic member, 631...First gathered elastic member, 632...Second gathered elastic member, 6 33...Third gathered elastic member, 64...Liquid impermeable sheet layer, 65...Nonwoven fabric absent area, 66...Side nonwoven fabric, 66r...Folded portion, 67...Fixing portion, 70...Side non-stretch area, 80...Planar gathered area, A1...Intermittent stretch band, A2...Continuous stretch band, B...Back body, BT...Back waist area, F...Front body, FT...Front waist area, HM1...First hot melt adhesive, HM2...Second hot melt adhesive Adhesive, HM3...Third hot melt adhesive, L...Intermediate region, LD...Front-to-back direction, M...Crotch area, SP...Urine receiving space, T...Waist area, U...Lower waist area, W...Waist area, WD...Width direction, WO...Waist opening, d1...First interval, d2...Second interval, d3...Third interval, w1...First distance, w2...Second distance, w3...Width dimension of the fixing part, w4...Third distance, w5...Fourth distance.

Claims

1. 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 over a range in the front-to-back direction including the crotch area, and a packaging sheet that encloses the absorbent body. The absorbent material is made by mixing and accumulating pulp fibers and superabsorbent polymer particles. The absorbent body has a pair of elongated slits extending in the front-to-back direction, provided on one and the other sides in the width direction of the crotch area, The absorbent has a center region defined as the space between one slit and the other slit, and a pair of side regions defined as the space between the slit and the side edge of the absorbent on both sides in the width direction. In the center region and the side region, grooves are provided in a continuous pattern in the width direction, extending over 60% or more of their front-to-back range, with grooves having a bottom that is recessed from at least one of the front and back surfaces of the absorbent into the absorbent and compressed in the thickness direction. The center region, compared to the side region, has either a constant thickness at the bottom of the groove and a low area ratio at the bottom of the groove, or a constant area ratio at the bottom of the groove and a thicker thickness at the bottom of the groove, or a low area ratio at the bottom of the groove and a thicker thickness at the bottom of the groove. Disposable diapers characterized by the following features.

2. The center region and the side region are regions in which the grooves are continuous in a grid pattern, The thickness and width of the bottom of the groove are the same in the center region and the side region, The maximum area of ​​the unit frame consisting of the grooves in the center region is 1.5 to 4 times the maximum area of ​​the unit frame consisting of the grooves in the side region. A disposable diaper according to claim 1.

3. The absorbent material consists of one or more layers formed by mixing and accumulating pulp fibers and superabsorbent polymer particles. The basis weight of the pulp fibers in the absorbent material is 80 to 450 g / m². ２ And, The weight ratio of pulp fibers to superabsorbent polymer particles in the absorbent material is 20:80 to 80:

20. The maximum thickness of the absorbent is 1 to 20 mm. The thickness of the bottom portion is 5 to 40% of the maximum thickness of the absorber. The width of the bottom is 1 to 3 mm. The area of ​​the unit frame consisting of the groove in the center region is 150 to 500 mm². ２ That is, The disposable diaper according to claim 2.

4. The groove is formed in an oblique grid pattern, consisting of a first portion inclined 40 to 60° clockwise in a plan view with respect to the front-rear direction, and a second portion inclined 40 to 60° counterclockwise in a plan view with respect to the front-rear direction. A disposable diaper according to claim 2 or 3.

5. The widthwise dimension of the unit frame in the side region is 0.5 times or less the minimum widthwise dimension of the side region. A disposable diaper according to claim 2 or 3.

6. The groove pattern in both side regions consists only of a slit-adjacent frame consisting of the side edge of the slit and the groove, a side-edge-adjacent frame consisting of the side edge of the absorber and the groove, and a complete unit frame having the same dimensions and shape. The area of ​​each slit-adjacent frame and the area of ​​each side-edge-adjacent frame in both of the aforementioned side regions are smaller than the area of ​​the unit frame. A disposable diaper according to claim 5.

7. The two side edges of the absorbent extend linearly along the front-to-back direction, The pair of slits extend from the middle in the front-rear direction toward the front and rear sides, respectively, approaching the side edges of the absorber. A disposable diaper according to claim 1 or 2.

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