Underpants-type disposable diaper

Abstract

An underpants-type disposable diaper according to one embodiment comprises: an absorbent body that includes a ventral part positioned on the ventral side of a wearer when worn, a dorsal part positioned on the dorsal side of the wearer, and a crotch part disposed between the ventral part and the dorsal part, the absorbent body extending in a longitudinal direction between the ventral side and the dorsal side when worn; and a waist part that is bonded to the ventral part and the dorsal part and that extends in the waist direction of the wearer, the waist part including a skin surface sheet disposed on a skin surface side, a non-skin surface sheet disposed on a non-skin surface side, and a plurality of elastic members arranged between the skin surface sheet and the non-skin surface sheet. The waist part includes a stretchable region which is stretchable in the waist direction in response to expansion and contraction of the plurality of elastic members, and a low-stretch region having a lower stretchability than that of the stretchable region. The low-stretch region has a through-hole penetrating the waist part in the thickness direction, and the skin surface sheet and the non-skin surface sheet in the low-stretch region are directly bonded to each other at least around the through-hole.

Description

Pants-type disposable diapers

[0001] The present disclosure relates to pant-type disposable diapers.

[0002] Patent Document 1 describes a diaper that includes an absorbent main body having an absorbent body, a ventral outer member that covers the ventral side of the wearer, and a dorsal outer member that covers the dorsal side of the wearer, and that has through-holes that pass through the ventral outer member and the dorsal outer member from the skin side to the non-skin side so as to overlap with the elastic members of the ventral outer member and the dorsal outer member.

[0003] International Publication No. 2017 / 175289

[0004] In the diaper described in Patent Document 1, through-holes are formed in the ventral and dorsal outer members to improve the breathability of the diaper. However, the opening area of ​​the through-holes depends on the body shape and posture of the wearer. For example, in the case of a slightly underweight wearer, the through-holes do not widen sufficiently in the direction of the wearer's waist, making it difficult to ensure the desired opening area. On the other hand, in the case of a slightly overweight wearer, the through-holes may widen too much in the direction of the wearer's waist, causing them to collapse in the vertical direction, making it impossible to ensure the desired opening area. Therefore, depending on the wearer's body shape and posture, it may be difficult to achieve the desired breathability.

[0005] Therefore, an object of the present disclosure is to provide a pants-type diaper that can improve breathability.

[0006] A pants-type disposable diaper according to one embodiment includes an absorbent main body that, when worn, extends longitudinally between the abdominal and dorsal sides of the diaper; an absorbent body that, when worn, extends longitudinally between the abdominal and dorsal sides of the diaper; and a waist portion that is joined to the abdominal and dorsal sides and extends in the waist direction of the wearer, the waist portion including a skin-facing sheet arranged on the skin-facing side, a non-skin-facing sheet arranged on the non-skin-facing side, and a plurality of elastic members arranged between the skin-facing sheet and the non-skin-facing sheet. The waist portion includes a stretchable region that can stretch in the waist direction in accordance with the stretching of the plurality of elastic members, and a low-stretch region that has lower stretchability than the stretchable region. The low-stretch region has a through-hole that penetrates the waist portion in the thickness direction, and the skin-facing sheet and the non-skin-facing sheet in the low-stretch region are directly joined to each other at least around the through-hole.

[0007] In the above-mentioned pants-type disposable diaper, the through-holes are formed in the low-stretch region, which has relatively low stretchability, so that deformation of the through-holes due to stretching of the multiple elastic members in accordance with the wearer's body shape, posture, etc. is suppressed, making it easier to maintain the opening area of ​​the through-holes, and as a result, the breathability of the pants-type diaper can be improved.

[0008] The skin-facing sheet and the non-skin-facing sheet may be directly bonded to each other with an adhesive throughout the entire low-elasticity region, which prevents the skin-facing sheet from peeling from the through-holes formed in the low-elasticity region.

[0009] The skin-facing sheet and the non-skin-facing sheet in the stretched region may have a non-adhesive region between the multiple elastic members that is not directly bonded to each other. The presence of the non-adhesive region between the multiple elastic members allows wrinkles to form in the non-adhesive region when the multiple elastic members contract, allowing the stretched region to efficiently contract in the waist direction. As described above, the contractile force of the multiple elastic members acts efficiently on the stretched region, making it less likely for the contractile force to act on the low-stretch region. Therefore, contraction of the low-stretch region is suppressed, and as a result, deformation of the through-holes can be suppressed.

[0010] The pants-type disposable diaper may further include a cover sheet attached to the skin-facing sheet of the waist portion from the skin-facing side so as to cover the through-holes. By providing the cover sheet so as to cover the through-holes, the feel of the diaper can be improved and urine leakage through the through-holes can be suppressed.

[0011] The cover sheet includes an adhesive region that is adhered to the skin-facing sheet with an adhesive and a non-adhesive region that is not adhered to the skin-facing sheet with an adhesive, and the adhesive region may overlap at least a portion of the stretch region and the non-adhesive region may overlap the low-stretch region when viewed in the thickness direction of the waistband section. By arranging the non-adhesive region so that it overlaps the low-stretch region, it is possible to prevent the adhesive from leaking out through the through-holes formed in the low-stretch region.

[0012] The non-adhesive area of ​​the cover sheet may be embossed to be pressed onto the face sheet, which allows the cover sheet and face sheet to be joined together while preventing adhesive from leaking out of the through holes formed in the low-stretch area.

[0013] The recesses or protrusions formed by embossing may be arranged in a direction inclined relative to the waistline direction. If embossing is performed in a direction parallel to the waistline direction, the formation of the recesses or protrusions may be hindered by the elastic member extending in the waistline direction. In contrast, by performing embossing in a direction inclined relative to the waistline direction, the formation of the recesses or protrusions is prevented from being hindered by the elastic member. As a result, the cover sheet and the skin-contact sheet can be firmly bonded.

[0014] The contour line of the through hole may be a smooth curve having a continuous curvature, in which case peeling between the skin-facing sheet and the non-skin-facing sheet is suppressed starting from the part corresponding to the corner of the through hole.

[0015] The contour line of the through hole may have a radius of curvature of 2.5 mm or more. By increasing the radius of curvature of the contour line of the through hole, peeling between the skin-facing sheet and the non-skin-facing sheet can be effectively suppressed starting from the parts corresponding to the corners of the through hole.

[0016] The ventral and dorsal portions of the absorbent main body are bonded to the skin-facing sheet of the waistband portion via an adhesive layer, which may extend continuously in the waistband direction. In this case, the rigidity of the absorbent main body is improved, suppressing shrinkage of the low-elasticity region in the waistband direction. As a result, deformation of the through-holes can be suppressed.

[0017] A method for manufacturing a pants-type disposable diaper according to one embodiment includes a waist portion including a skin-facing sheet disposed on the skin-facing side, a non-skin-facing sheet disposed on the non-skin-facing side, and a plurality of elastic members disposed between the skin-facing sheet and the non-skin-facing sheet. The method includes the steps of: applying an adhesive to the plurality of elastic members; arranging the plurality of adhesive-coated elastic members along the conveyance direction between a strip-shaped skin-facing sheet in which the skin-facing sheet is continuous in the conveyance direction and a strip-shaped non-skin-facing sheet in which the non-skin-facing sheet is continuous in the conveyance direction, thereby forming a bonded sheet in which the strip-shaped skin-facing sheet and the strip-shaped non-skin-facing sheet are bonded to each other via the plurality of elastic members; cutting a portion of the plurality of elastic members while forming through-holes that penetrate the bonded sheet in the thickness direction to form stretchable regions that are stretchable in the conveyance direction and low-stretch regions that have lower stretchability than the stretchable regions; and cutting the bonded sheet at predetermined intervals in the conveyance direction to form a waist portion including the stretchable regions and the low-stretch regions.

[0018] According to the above method, a pants-type disposable diaper having a waist portion including a stretchable region and a low-stretchable region, with a through-hole formed in the low-stretchable region, is manufactured. By forming the through-hole in the low-stretchable region, which has relatively low stretchability, deformation of the through-hole in response to stretching of the multiple elastic members is suppressed, making it easier to maintain the opening area of ​​the through-hole. As a result, the breathability of the pants-type diaper manufactured can be improved.

[0019] The method may further include a step of removing by suction some of the elastic members cut when the through holes are formed, in which case the elastic members cut when the through holes are formed are less likely to remain in the low-elasticity region.

[0020] The method may further include a step of making a slit in the low-elasticity region of the bonded sheet along a direction perpendicular to the conveying direction, in which case the elastic member remaining in the low-elasticity region is cut off, thereby reducing the elasticity of the low-elasticity region.

[0021] The above method may further include the step of applying an adhesive to the intended bonding areas of the strip-like skin face sheet or the strip-like non-skin face sheet to directly bond the strip-like skin face sheet and the strip-like non-skin face sheet to each other in the intended bonding areas before forming the through holes, and forming through holes in the joining sheet so as to pass through the intended bonding areas. By directly bonding the strip-like skin face sheet and the strip-like non-skin face sheet in the intended bonding areas, it is possible to prevent the strip-like skin face sheet and the strip-like non-skin face sheet from peeling off when the through holes are formed.

[0022] The method may include the steps of placing a cover sheet on the strip-shaped skin-facing sheet of the joining sheet so as to cover the through-holes, adhering the cover sheet to the stretchable region of the joining sheet with an adhesive, and embossing the cover sheet to press the cover sheet to the low-stretchable region of the joining sheet. By pressing the cover sheet to the low-stretchable region by embossing, the cover sheet can be firmly joined to the skin-facing sheet while preventing adhesive from leaking out of the through-holes formed in the low-stretchable region.

[0023] According to various aspects of the present invention, the breathability of a pants-type disposable diaper can be improved.

[0024] 5 is a perspective view schematically illustrating a pants-type disposable diaper according to one embodiment; FIG. 6 is a plan view of the pants-type disposable diaper as viewed from the skin-facing side; FIG. 7 is a plan view of the pants-type disposable diaper as viewed from the non-skin-facing side; FIG. 8 is a schematic cross-sectional view of the absorbent main body taken along line A-A in FIG. 2; FIG. 9 is a schematic plan view of the back waist portion as viewed from the non-skin-facing side; and FIG. 10 is a schematic cross-sectional view of the back waist portion taken along line B-B in FIG. 5. (a) to (d) are diagrams showing examples of opening shapes of perforations. FIG. 11 is a flowchart illustrating a method for manufacturing a pants-type disposable diaper according to one embodiment; and FIG. 12 is a diagram schematically illustrating an example of a manufacturing apparatus for a pants-type disposable diaper. (a) is a plan view showing a portion of a strip-shaped non-skin-facing sheet, and (b) is a plan view showing a portion of a bonded sheet in which through-holes are formed.

[0025] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios are not limited to those shown in the drawings.

[0026] A pants-type disposable diaper 1 (hereinafter referred to as "diaper 1") according to one embodiment will be described below. Fig. 1 is a perspective view of the diaper 1 according to one embodiment. Fig. 2 is a plan view of the diaper 1 as viewed from the skin-facing side Z1, and Fig. 3 is a plan view of the diaper 1 as viewed from the non-skin-facing side Z2.

[0027] The skin-facing side Z1 is the side that faces the wearer's skin when the diaper 1 is worn, and the non-skin-facing side Z2 is the side that faces away from the wearer's skin when the diaper 1 is worn. In the following description, a person who wears the diaper 1 will be referred to as a "wearer," and a person who helps the wearer put the diaper 1 on will be referred to as a "user." Typically, the wearer is a child or a person being cared for, and the user is a parent or caregiver.

[0028] 2 and 3 show the diaper 1 in an unfolded state in which the diaper 1 has been cut at side end portions 34 of the ventral waistband portion 3 and side end portions 44 of the back waistband portion 4, which will be described later, and stretched to a state in which no wrinkles are formed. As shown in FIGS. 2 and 3, the diaper 1 in the unfolded state extends in a transverse direction X and a longitudinal direction Y. The longitudinal direction Y corresponds to the longitudinal direction L of the diaper 1, which extends between the ventral side and the back side of the wearer when the diaper 1 is worn. The transverse direction X is a direction perpendicular to the longitudinal direction Y, and is a width direction extending from side to side of the wearer when the diaper 1 is worn. The thickness direction Z is a direction perpendicular to the transverse direction X and the longitudinal direction Y.

[0029] The diaper 1 includes a ventral waistband portion 3, a rear waistband portion 4, and an absorbent body 10. The absorbent body 10 has a generally rectangular planar shape that is elongated in the longitudinal direction Y of the diaper 1. As shown in FIGS. 2 and 3 , the absorbent body 10 includes a ventral portion 10a disposed at one end of the longitudinal direction Y, a rear portion 10b disposed at the other end of the longitudinal direction Y, and a crotch portion 10c disposed between the ventral portion 10a and the rear portion 10b in the longitudinal direction Y. The ventral portion 10a is positioned on the ventral side of the wearer when worn, and the rear portion 10b is positioned on the rear side of the wearer when worn. The crotch portion 10c is positioned to cover the crotch of the wearer when worn. In the following description, the direction from the ventral portion 10a to the rear portion 10b in the longitudinal direction Y may be referred to as the "rear side," and the direction from the rear portion 10b to the ventral portion 10a may be referred to as the "rear side."

[0030] The ventral waist portion 3 is joined to the ventral portion 10a of the absorbent main body 10 from the non-skin-facing side Z2. The back waist portion 4 is joined to the back portion 10b of the absorbent main body 10 from the non-skin-facing side Z2. The diaper 1 is formed by folding the absorbent main body 10 in half so that the ventral waist portion 3 and the back waist portion 4 face each other, and joining the lateral end portions 34 of the ventral waist portion 3 in the lateral direction X to the lateral end portions 44 of the back waist portion 4 in the lateral direction X at the joining portions 18, thereby connecting the ventral waist portion 3 and the back waist portion 4 in a belt-like manner. As a result, the diaper 1 is formed into a pants-type diaper, as shown in FIG. 1 . In the following description, the state in which the ventral waist portion 3 and the back waist portion 4 are connected in a belt-like manner as described above will be referred to as a "connected state." The ventral waist portion 3 and the back waist portion 4 in the connected state constitute the waist portion 2 that extends in the waist circumference direction R of the wearer when worn. The waist portion 2 expands and contracts in the waist direction R in response to expansion and contraction of a plurality of elastic members 33, 43, which will be described later. As shown in Fig. 1, the diaper 1 in the connected state has a waist opening BH through which the wearer's waist passes and a pair of leg openings LH through which the wearer's legs pass.

[0031] Figure 4 is a schematic cross-sectional view of the absorbent main body 10 taken along line A-A in Figure 2. As shown in Figure 4, the absorbent main body 10 includes a topsheet 11, a backsheet 12, an exterior sheet 13, and an absorbent body 14. The topsheet 11 constitutes the surface of the absorbent main body 10 that contacts the wearer, and is disposed on the skin-facing side Z1. The topsheet 11 is made of a water-permeable nonwoven fabric such as a spunbond nonwoven fabric, and covers the absorbent body 14 from the skin-facing side Z1. The topsheet 11 is adhered to the surface of the skin-facing side Z1 of the absorbent body 14 with, for example, a hot melt adhesive HM.

[0032] The backsheet 12 is disposed closer to the non-skin-facing side Z2 than the topsheet 11. The backsheet 12 is made of a water-impermeable film and covers the absorbent body 14 from the non-skin-facing side Z2. The backsheet 12 is adhered to the surface of the non-skin-facing side Z2 of the absorbent body 14 with, for example, a hot melt adhesive HM.

[0033] The exterior sheet 13 is disposed on the non-skin-facing side Z2 of the back sheet 12 and constitutes the outermost layer of the absorbent body 10. The exterior sheet 13 is made of, for example, a water-impermeable nonwoven fabric. Typically, the exterior sheet 13 is plain white. The width of the exterior sheet 13 in the lateral direction X is greater than the width of the back sheet 12, and the exterior sheet 13 extends beyond the back sheet 12 on both sides in the lateral direction X.

[0034] The absorbent body 14 is disposed between the topsheet 11 and the backsheet 12 of the absorbent main body 10, and absorbs the wearer's urine that has permeated through the topsheet 11. As shown in Fig. 4, the absorbent body 14 includes an absorbent core 15 and a core wrap 16. The absorbent core 15 contains pulp fibers and a superabsorbent polymer (SAP) and absorbs the wearer's urine. In one embodiment, the absorbent core 15 has a layered structure in which a lower covering sheet 15a, a lower SAP layer 15b, an intermediate sheet 15c, an upper SAP layer 15d, and an upper covering sheet 15e are layered in this order from the bottom up.

[0035] The lower covering sheet 15a is a hydrophilic sheet containing pulp and covers the lower surface of the lower SAP layer 15b. The lower SAP layer 15b is a water-absorbing layer containing super absorbent polymers (SAP) and is disposed between the lower covering sheet 15a and the intermediate sheet 15c. The intermediate sheet 15c is a water-permeable sheet such as a nonwoven fabric and is disposed between the lower SAP layer 15b and the upper SAP layer 15d. The upper SAP layer 15d is a water-absorbing layer containing super absorbent polymers and is disposed between the intermediate sheet 15c and the upper covering sheet 15e. The upper covering sheet 15e is a hydrophilic sheet containing pulp and covers the upper surface of the upper SAP layer 15d.

[0036] Pulp constituting the lower covering sheet 15a and the upper covering sheet 15e may be, for example, chemical pulp, or cellulose fibers such as rayon or acetate. Superabsorbent polymers may be, for example, particulate or fibrous starch-, acrylic acid-, or amino acid-based polymers. The core wrap 16 is, for example, a tissue or nonwoven fabric sheet, and covers the skin-facing side Z1 and non-skin-facing side Z2 of the absorbent core 15. The core wrap 16 is adhered to the non-skin-facing side Z2 of the lower covering sheet 15a and the skin-facing side Z1 of the upper covering sheet 15e, for example, with a hot melt adhesive HM. Urine and other excrement excreted in the absorbent body 10 passes through the topsheet 11 and the upper covering sheet 15e and is absorbed by the upper SAP layer 15d. Excrement not absorbed by the upper SAP layer 15d passes through the intermediate sheet 15c and is absorbed by the lower SAP layer 15b.

[0037] As shown in Figures 2 and 4, a pair of channel portions 20 are formed in the upper SAP layer 15d of the absorbent core 15. The basis weight of the pair of channel portions 20 is set lower than the basis weight of the remaining portions of the absorbent core 15. That is, the density of the superabsorbent polymer in the pair of channel portions 20 is lower than the density of the superabsorbent polymer in the remaining portions of the absorbent core 15. In one embodiment, as shown in Figure 4, the pair of channel portions 20 are non-penetrating grooves recessed from the surface of the skin-facing side Z1 of the upper SAP layer 15d toward the non-skin-facing side Z2. Note that the pair of channel portions 20 may also be slits penetrating the upper SAP layer 15d in the thickness direction Z.

[0038] As shown in Fig. 2, the pair of channel portions 20 are disposed symmetrically with respect to the center line CW of the absorbent main body 10 in the transverse direction X, and extend linearly in the longitudinal direction Y across substantially the entire area of ​​the absorbent core 15. The formation of the pair of channel portions 20 in the absorbent core 15 allows urine excreted by the wearer to be diffused in the longitudinal direction Y. In other words, the pair of channel portions 20 have the function of controlling the flow direction of urine. Two of the multiple through holes 50 described below are disposed on an extension line of the pair of channel portions 20. This forms a path for air to pass through the pair of channel portions 20 and head toward the two through holes 50 within the diaper 1.

[0039] As shown in Fig. 2, the absorbent main body 10 has a pair of leak-proof gathers 80. The leak-proof gathers 80 are arranged on the outer sides of the absorbent core 15 in the lateral direction X, and prevent urine excreted into the absorbent core 15 from leaking in the lateral direction X. As shown in Fig. 4, the leak-proof gathers 80 are formed by folding inward both left-right side portions of the outer sheet 13. The pair of leak-proof gathers 80 are upright three-dimensional gathers and are provided on the absorbent main body 10 along the longitudinal direction Y.

[0040] The leak-proof gathers 80 include a pair of elastic members 22 extending in the vertical direction Y, an upright portion 81 that stands up due to contraction of the pair of elastic members 22, a horizontal fixing portion 82 that serves as an upright fulcrum for the upright portion 81 in the horizontal direction X, and a vertical fixing portion 83 that serves as an upright fulcrum for the upright portion 81 in the vertical direction Y.

[0041] The pair of elastic members 22 are disposed between the inwardly folded outer sheet 13 and extend in the longitudinal direction Y. The pair of elastic members 22 are, for example, rubber threads or flat elastic members that are contractible in the longitudinal direction. The pair of elastic members 22 are disposed spaced apart from each other across a center line CW that divides the absorbent main body 10 into two in the transverse direction X, and are fixed to the outer sheet 13 in a stretched state in the longitudinal direction Y. The ventral side ends of the pair of elastic members 22 are disposed in the ventral side portion 10a, and the dorsal side ends of the pair of elastic members 22 are disposed in the dorsal side portion 10b.

[0042] The lateral fixing parts 82 are formed on the outer sides of the standing parts 81 in the lateral direction X, over substantially the entire area of ​​the absorbent main body 10 in the longitudinal direction Y. The lateral fixing parts 82 are part of the exterior sheet 13, and are joined to the topsheet 11 or the backsheet 12. For example, a hot melt adhesive HM is used to join the lateral fixing parts 82 (see FIG. 4 ). The lateral fixing parts 82 serve as standing fulcrums for the standing parts 81 in the lateral direction X.

[0043] The vertical fixing portions 83 are formed at positions inside the horizontal fixing portions 82 in the horizontal direction X. The vertical fixing portions 83 are part of the exterior sheet 13 and are joined to the top sheet 11 or the back sheet 12. For example, a hot melt adhesive is used to join the vertical fixing portions 83. The vertical fixing portions 83 include a ventral side fixing portion 84 and a dorsal side fixing portion 85. The ventral side fixing portion 84 is formed on the ventral side portion 10a of the absorbent main body 10. The dorsal side fixing portion 85 is formed on the dorsal side portion 10b of the absorbent main body 10. The vertical fixing portions 83 serve as standing fulcrums for the standing portions 81 in the vertical direction Y.

[0044] The standing portion 81 is formed between the ventral fixing portion 84 and the dorsal fixing portion 85. That is, the standing portion 81 is positioned more inward in the lateral direction X than the lateral fixing portion 82, and more inward in the longitudinal direction Y than the longitudinal fixing portion 83. The standing portion 81 is a part of the exterior sheet 13 that is not fixed to the topsheet 11 or the backsheet 12. An elastic member 22 stretched in the longitudinal direction Y is connected to the standing portion 81. When the elastic member 22 contracts in the longitudinal direction Y, the standing portion 81 stands up from the lateral fixing portion 82 as a starting point. In this way, the standing portion 81 stands up so as to sandwich the absorbent core 15 from the lateral direction X, thereby preventing urine leakage.

[0045] As shown in FIG. 2 , the diaper 1 further includes a plurality of leg elastic members 40 that are stretchable in the longitudinal direction. The leg elastic members 40 are arranged outward in the transverse direction X from the pair of elastic members 22. The ventral ends of the leg elastic members 40 are arranged in the ventral portion 10a, and the dorsal ends of the leg elastic members 40 are arranged in the dorsal portion 10b. The leg elastic members 40 are made of a stretchable material, such as rubber or spandex, that is stretchable in the longitudinal direction. They are connected to the outer sheet 13 of the absorbent main body 10 along the side edges 10S of the absorbent main body 10 in a stretched state in the longitudinal direction Y. When the diaper 1 is worn, the leg elastic members 40 contract in the longitudinal direction Y, allowing the side edges 10S of the absorbent main body 10 to fit the legs of the wearer.

[0046] As shown in Fig. 3, the diaper 1 may have an indicator 72 that changes color upon contact with moisture. The indicator 72 is disposed at a position overlapping the absorbent body 14 when viewed from the thickness direction Z, and is provided on the outer sheet 13 so as to be visible from the non-skin-facing side Z2 of the absorbent main body 10. The indicator 72 changes color upon reaction with bodily fluid absorbed by the absorbent body 14. The color change of the indicator 72 allows the user to know the wetness of the absorbent body 14.

[0047] As shown in Fig. 3, the diaper 1 includes a post-treatment tape 24 for holding the diaper 1 in a rolled state when discarding it. The post-treatment tape 24 is a strip-shaped fastening tape provided on the outer surface of the back waistband 4 of the diaper 1. When discarding the diaper 1, the user tears the connected diaper 1 along the side end portions 34 of the ventral waistband 3 and the side end portions 44 of the back waistband 4, rolls the diaper 1 with the topsheet 11 facing inward, and adheres the post-treatment tape 24 to the outer surface of the diaper 1. This keeps the diaper 1 in a rolled state. The post-treatment tape 24 may be provided on the ventral waistband 3 or the outer sheet 13, as long as it is on the outer surface of the diaper 1. The post-treatment tape 24 is positioned so as not to overlap the multiple through-holes 50, which will be described later.

[0048] The ventral waist portion 3 has a generally rectangular planar shape with its longitudinal direction aligned with the transverse direction X of the diaper 1, and is disposed closer to the non-skin-facing side Z2 than the ventral portion 10a of the absorbent main body 10. The ventral waist portion 3 includes a skin-facing sheet 31 disposed on the skin-facing side Z1, a non-skin-facing sheet 32 ​​disposed on the non-skin-facing side Z2, and a plurality of elastic members 33. The ventral portion 10a of the absorbent main body 10 is adhered to the skin-facing sheet 31 of the ventral waist portion 3 via an adhesive layer. The adhesive layer may extend continuously in the waist-surrounding direction R.

[0049] Typically, the skin-facing sheet 31 and the non-skin-facing sheet 32 ​​are made of a plain white nonwoven fabric. For example, the skin-facing sheet 31 and the non-skin-facing sheet 32 ​​are made of an SMS nonwoven fabric in which spunbond, meltblown, and spunbond are laminated in this order, a spunbond nonwoven fabric, an air-through nonwoven fabric, or a laminate of these nonwoven fabrics. The skin-facing sheet 31 and the non-skin-facing sheet 32 ​​are joined to each other with a hot melt adhesive applied to the multiple elastic members 33. Therefore, non-adhesive regions are formed between the multiple elastic members 33 where the skin-facing sheet 31 and the non-skin-facing sheet 32 ​​are not directly adhered to each other.

[0050] In one embodiment, the non-skin-facing sheet 32 ​​may be made of a nonwoven fabric having numerous apertures, and the skin-facing sheet 31 may be made of a nonwoven fabric having no apertures. Note that the apertures referred to here do not refer to gaps between the fibers of the nonwoven fabric, but rather to through-holes formed by perforation processing. Therefore, the non-skin-facing sheet 32 ​​has a higher aperture rate than the skin-facing sheet 31. By making the aperture rate of the skin-facing sheet 31 relatively low, the feel of the diaper 1 against the skin is improved.

[0051] The plurality of elastic members 33 are disposed between the skin-facing sheet 31 and the non-skin-facing sheet 32, and are arranged at intervals d1 in the longitudinal direction Y. These plurality of elastic members 33 extend in the lateral direction X between the lateral end portions 34 of the ventral waistband 3. Therefore, the ventral waistband 3 stretches in the lateral direction X, i.e., in the waist-circumference direction R, while fitting around the waist of the wearer. The plurality of elastic members 33 are made of an elastic material such as rubber or spandex.

[0052] 2 and 3 , the ventral waist portion 3 has an upper edge 3a located on one side in the longitudinal direction Y and a lower edge 3b located on the other side in the longitudinal direction Y. In the longitudinal direction Y, the upper edge 3a is located closer to the ventral side than the ventral edge 10F of the absorbent main body 10. The lower edge 3b is located closer to the dorsal side than the ventral edge 10F of the absorbent main body 10. When worn, the longitudinal direction Y of the ventral waist portion 3 is oriented in a vertical direction perpendicular to the waist circumference direction R of the wearer, with the upper edge 3a located on the ventral side of the wearer and the lower edge 3b located on the crotch side of the wearer. The multiple elastic members 33 of the ventral waist portion 3 are arranged at intervals d1 in the longitudinal direction Y between the upper edge 3a and the lower edge 3b.

[0053] 3, the ventral waistline portion 3 includes a first highly elastic region R31, a second highly elastic region R32, a third highly elastic region R33, and a low-elastic region R34. The first highly elastic region R31, the second highly elastic region R32, and the third highly elastic region R33 are regions in which a plurality of elastic members 33 are arranged between the skin-facing sheet 31 and the non-skin-facing sheet 32, and are stretchable in the lateral direction X.

[0054] 3 , the first high-elasticity region R31 is disposed adjacent to the side edge 34 of the ventral waistline portion 3. The second high-elasticity region R32 is disposed adjacent to the side edge 34 and is spaced apart from the first high-elasticity region R31 in the lateral direction X (waistline direction R). The third high-elasticity region R33 is disposed at a position offset from the first high-elasticity region R31 and the second high-elasticity region R32 in the longitudinal direction Y, and is provided across the entire ventral waistline portion 3 in the lateral direction X. For example, the third high-elasticity region R33 is disposed between the low-elasticity region R34 and the upper edge 3 a of the ventral waistline portion 3.

[0055] The low-elasticity region R34 is disposed between the first high-elasticity region R31 and the second high-elasticity region R32. The low-elasticity region R34 is a region where the multiple elastic members 33 are not substantially disposed between the skin-facing sheet 31 and the non-skin-facing sheet 32, and has lower elasticity than the first high-elasticity region R31, the second high-elasticity region R32, and the third high-elasticity region R33. The low-elasticity region R34 is formed, for example, by cutting some of the multiple elastic members 33 midway in the lateral direction X. Note that some of the cut multiple elastic members 33 may remain in the low-elasticity region R34. The low-elasticity region R34 is disposed in a position overlapping the absorbent main body 10 when viewed from the thickness direction Z. By arranging the low-elasticity region R34 so as to overlap the absorbent main body 10, the contractile force of the multiple elastic members 33 is less likely to act on the absorbent main body 10, thereby suppressing contraction of the absorber 14 in the lateral direction X.

[0056] As described above, the low-elasticity region R34 is disposed adjacent to the first high-elasticity region R31 and the second high-elasticity region R32 in the lateral direction X, and adjacent to the third high-elasticity region R33 in the longitudinal direction Y. Typically, the low-elasticity region R34 is disposed in the central portion of the ventral waistline portion 3 in the lateral direction X. The width W2 of the low-elasticity region R34 in the lateral direction X may be smaller than the width W1 of the ventral side edge 10F of the absorbent main body 10 in the lateral direction X.

[0057] 1, a decoration 25 may be applied to the exterior sheet 13 in a position overlapping the low-stretch region R34. The decoration 25 may have a design that evokes high breathability. Examples of the decoration 25 that evokes high breathability include an illustration of an open window or an illustration of wavy lines representing wind.

[0058] The back waist portion 4 has a generally rectangular planar shape that is elongated in the lateral direction X of the diaper 1, and is disposed closer to the non-skin-facing side Z2 than the back portion 10b of the absorbent main body 10. The back waist portion 4 includes a skin-facing sheet 41 disposed on the skin-facing side Z1, a non-skin-facing sheet 42 disposed on the non-skin-facing side Z2, and a plurality of elastic members 43. The back portion 10b of the absorbent main body 10 is adhered to the skin-facing sheet 41 of the back waist portion 4 via an adhesive layer. The adhesive layer may extend continuously in the lateral direction X (waist-surrounding direction R).

[0059] Typically, the skin-facing sheet 41 and the non-skin-facing sheet 42 are made of a plain white nonwoven fabric. For example, the skin-facing sheet 41 and the non-skin-facing sheet 42 are made of an SMS nonwoven fabric in which spunbond, meltblown, and spunbond are laminated in this order, a spunbond nonwoven fabric, an air-through nonwoven fabric, or a laminate of these nonwoven fabrics. The skin-facing sheet 41 and the non-skin-facing sheet 42 are joined to each other with a hot melt adhesive applied to multiple elastic members 43. Therefore, non-adhesive regions where the skin-facing sheet 41 and the non-skin-facing sheet 42 are not directly adhered to each other are formed between the multiple elastic members 43.

[0060] In one embodiment, the non-skin-facing sheet 42 may be made of a porous nonwoven fabric having numerous openings, and the skin-facing sheet 41 may be made of a nonwoven fabric having no openings. Note that the openings referred to here do not refer to gaps between the fibers of the nonwoven fabric, but rather to through-holes formed by perforation. Therefore, the opening rate of the non-skin-facing sheet 42 is higher than that of the skin-facing sheet 41. By making the opening rate of the skin-facing sheet 41 relatively low, the feel of the diaper 1 against the skin is improved.

[0061] The plurality of elastic members 43 are disposed between the skin-facing sheet 41 and the non-skin-facing sheet 42 and are arranged at intervals d2 in the longitudinal direction Y. The plurality of elastic members 43 extend in the lateral direction X between the lateral end portions 44 of the back-side waistband portion 4 in the lateral direction X. Therefore, the back-side waistband portion 4 stretches in the lateral direction X, i.e., in the waist-circumference direction R, while fitting around the waist of the wearer. The plurality of elastic members 43 are made of an elastic material such as rubber thread or spandex.

[0062] 2 and 3, the back waist portion 4 has an upper edge 4a located on one side in the longitudinal direction Y and a lower edge 4b ​​located on the other side in the longitudinal direction Y. In the longitudinal direction Y, the upper edge 4a is located on the dorsal side of the dorsal edge 10R of the absorbent main body 10. The lower edge 4b ​​is located on the ventral side of the dorsal edge 10R of the absorbent main body 10. When worn, the longitudinal direction Y of the back waist portion 4 is oriented in a vertical direction perpendicular to the waist direction R of the wearer, with the upper edge 4a located on the dorsal side of the wearer and the lower edge 4b ​​located on the crotch side of the wearer. The multiple elastic members 33 of the back waist portion 4 are arranged at a predetermined interval d2 in the longitudinal direction Y between the upper edge 4a and the lower edge 4b.

[0063] Fig. 5 is a schematic plan view of the back waist portion 4 as seen from the non-skin-facing side Z2. Fig. 6 is a schematic cross-sectional view of the back waist portion 4 taken along line B-B in Fig. 5. Note that in the cross-sectional view shown in Fig. 6, for ease of explanation, the components are shown spaced apart in the thickness direction Z, but in reality, they are in contact with each other in the thickness direction Z. In one embodiment, as shown in Fig. 6, the non-skin-facing sheet 42 includes a folded-back portion 45 folded back toward the skin-facing side Z1 at the upper edge 4a. At least a portion of the folded-back portion 45 is positioned closer to the skin-facing side Z1 than the skin-facing sheet 41.

[0064] 3 and 5, the back waist portion 4 includes a first highly elastic region R41, a second highly elastic region R42, a third highly elastic region R43, and a low-elastic region R44. The first highly elastic region R41, the second highly elastic region R42, and the third highly elastic region R43 are regions in which a plurality of elastic members 43 are arranged between the skin-facing sheet 41 and the non-skin-facing sheet 42, and are stretchable in the lateral direction X.

[0065] 5 , the first high-elasticity region R41 is disposed adjacent to a side edge 44 of the back waistline portion 4. The second high-elasticity region R42 is disposed adjacent to the side edge 44 and is spaced apart from the first high-elasticity region R41 in the horizontal direction X (waistline direction R). The third high-elasticity region R43 is disposed at a position offset from the first high-elasticity region R41 and the second high-elasticity region R42 in the vertical direction Y and is provided across the entire back waistline portion 4 in the horizontal direction X. For example, the third high-elasticity region R43 is disposed between the low-elasticity region R44 and the upper edge 4a of the back waistline portion 4.

[0066] The low-elasticity region R44 is disposed between the first high-elasticity region R41 and the second high-elasticity region R42. The low-elasticity region R44 is a region where substantially no elastic members 43 are disposed between the skin-facing sheet 41 and the non-skin-facing sheet 42, and has lower elasticity than the first high-elasticity region R41, the second high-elasticity region R42, and the third high-elasticity region R43. The low-elasticity region R44 is formed, for example, by cutting some of the elastic members 43 midway in the lateral direction X. Note that some of the cut elastic members 43 may remain in the low-elasticity region R44.

[0067] As described above, the low-elasticity region R44 is disposed adjacent to the first high-elasticity region R41 and the second high-elasticity region R42 in the lateral direction X, and adjacent to the third high-elasticity region R43 in the longitudinal direction Y. Typically, the low-elasticity region R44 is disposed in the center of the back waistband portion 4 in the lateral direction X. As shown in FIG. 3 , the width W3 of the low-elasticity region R44 in the lateral direction X may be smaller than the width W4 of the back edge 10R of the absorbent main body 10 in the lateral direction X. By making the width W3 of the low-elasticity region R44 smaller than the width W4 of the back edge 10R of the absorbent main body 10 in the lateral direction X, contraction of the low-elasticity region R44 is suppressed by the rigidity of the absorbent main body 10.

[0068] Furthermore, the width L2 of the low-elasticity region R44 in the longitudinal direction Y may be equal to or less than one-fourth the length of the side end portion 44 of the back waist portion 4 in the longitudinal direction Y, i.e., the length L1 of the joint portion 18 (see FIG. 3 ). By making the width L2 of the low-elasticity region R44 in the longitudinal direction Y relatively small, the contractile force of the waist portion 2 in the waist direction R is ensured, thereby improving the fit of the diaper 1.

[0069] As shown in Fig. 5, the low-elasticity region R44 is formed with a plurality of through-holes 50 that penetrate the back waistband 4 in the thickness direction Z. As shown in Fig. 6, the through-holes 50 penetrate the skin-facing sheet 41 and the non-skin-facing sheet 42 of the back waistband 4 in the thickness direction Z. The through-holes 50 have the function of discharging air from within the diaper 1 to the outside of the diaper 1, thereby improving breathability. In particular, since a wearer is prone to sweating on their backs, forming the through-holes 50 in the back waistband 4 can improve comfort when wearing the diaper 1.

[0070] The through-hole 50 is formed by making an annular cut in the low-elasticity region R44 and hollowing out a portion of the skin-facing sheet 41 and the non-skin-facing sheet 42 in the low-elasticity region R44. That is, the through-hole 50 has a certain opening area. Note that the annular cut means cutting a portion of the low-elasticity region R44 of the back waistline portion 4 all the way around, and the planar shape is not limited to a circular ring, but may include any ring shape such as a rectangular ring or a polygonal ring.

[0071] For example, as shown in FIG. 5 , the through hole 50 has a heart-shaped opening. As shown in FIGS. 7( a ) to 7 ( d ), the opening shape of the through hole 50 is not limited to a heart shape and can have various other shapes. FIG. 7( a ) shows a round through hole 50, and FIG. 7( b ) shows an animal (cat)-shaped through hole 50. FIG. 7( c ) shows a wing-shaped through hole 50, and FIG. 7( d ) shows a through hole 50 with a shape combining a heart and a wing. The opening shape of the through hole 50 may be elliptical, semicircular, teardrop-shaped, diamond-shaped, polygonal, or the like. Because the through hole 50 is formed in the low-elasticity region R44, there is a region around the through hole 50 where the multiple elastic members 43 are not arranged. Therefore, the contractile force of the multiple elastic members 43 prevents the through hole 50 from closing.

[0072] The contour line of the through hole 50 may be a smooth curve having a continuous curvature. For example, the contour line of the through hole 50 may have a radius of curvature of 2.5 mm or more. The radius of curvature of the contour line refers to the minimum radius of curvature of the contour line of the through hole 50. When the contour line of the through hole 50 is a smooth curve, peeling of the skin-contact sheet 41 and the non-skin-contact sheet 42 of the back waistline portion 4 from the portions corresponding to the corners of the through hole 50 is suppressed. Furthermore, the portions corresponding to the corners are prevented from coming into contact with the wearer, thereby preventing the diaper 1 from feeling uncomfortable against the skin.

[0073] Furthermore, the opening width H of the through-holes 50 in the vertical direction Y (the up-down direction when worn) may be larger than the predetermined spacing d2 between the multiple elastic members 43 in the vertical direction Y. The opening width H means the maximum width of the through-holes 50 in the vertical direction Y. By increasing the opening width H of the multiple through-holes 50, the opening area of ​​the multiple through-holes 50 increases, thereby improving the breathability of the diaper 1.

[0074] In one embodiment, as shown in FIG. 5 , the plurality of through holes 50 are arranged in the horizontal direction X (the waist-circumference direction R) within the low-stretch region R44. The plurality of through holes 50 may also be arranged in the vertical direction Y, or in a direction inclined relative to the horizontal direction X and the vertical direction Y. The plurality of through holes 50 may also be arranged along an arch-shaped curve, or may be distributed two-dimensionally within the low-stretch region R44. The opening areas of the through holes 50 may be equal to or different from each other. The opening area of ​​the through holes 50 can be measured as follows. First, the diaper 1 is removed from the package, and the waist portion 2 is pulled left and right to smooth out any wrinkles in the low-stretch region R44. Next, a photograph is taken from directly above the through hole 50. Finally, the photographed image is analyzed using general area analysis software to measure the opening area of ​​the through hole 50. It is sufficient that at least one through hole 50 is formed in the low-stretch region R44. 5, four through holes 50 are arranged in the horizontal direction X. Of the four through holes 50, the two central through holes 50 in the horizontal direction X are arranged on an extension line of a pair of channel portions 20 (see FIG. 2).

[0075] When the upper region 46 of the low-elasticity region R44 is located closer to the upper edge 4a than the center line CL of the low-elasticity region R44 in the longitudinal direction Y, and the lower region 47 is located closer to the lower edge 4b ​​than the center line CL of the low-elasticity region R44 in the longitudinal direction Y, the opening area of ​​the plurality of through holes 50 in the upper region 46 may be larger than the opening area of ​​the plurality of through holes 50 in the lower region 47. For example, when the plurality of through holes 50 are arranged in the longitudinal direction Y, the opening area of ​​each through hole 50 may decrease from the back side to the ventral side. This increases the opening area of ​​the plurality of through holes 50 on the back side where sweating is more likely, allowing moisture inside the diaper 1 to be efficiently discharged through the plurality of through holes 50.

[0076] The skin-facing sheet 41 and the non-skin-facing sheet 42 in the low-elasticity region R44 are directly bonded to each other at least around the through-holes 50. Direct bonding of the skin-facing sheet 41 and the non-skin-facing sheet 42 means that the skin-facing sheet 41 and the non-skin-facing sheet 42 are bonded in contact with each other without an elastic member 43 interposed between them. In one embodiment, the skin-facing sheet 41 and the non-skin-facing sheet 42 may be directly bonded to each other with an adhesive throughout substantially the entire low-elasticity region R44. As described above, in the first high-elasticity region R41, the second high-elasticity region R42, and the third high-elasticity region R43, the skin-facing sheet 41 and the non-skin-facing sheet 42 are bonded to each other via the elastic member 43, whereas in the low-elasticity region R44, the skin-facing sheet 41 and the non-skin-facing sheet 42 are directly bonded to each other with an adhesive.

[0077] 3 and 6 , the plurality of through-holes 50 are arranged in the longitudinal direction Y between the back edge 10R of the absorbent main body 10 and the upper edge 4a of the back waistline portion 4. That is, the plurality of through-holes 50 are arranged at positions that do not overlap with the absorbent main body 10 when viewed from the thickness direction Z. As a result, the flow of air through the plurality of through-holes 50 is not obstructed, and the breathability of the diaper 1 can be improved.

[0078] In one embodiment, the diaper 1 further includes a cover sheet 60. As shown in Fig. 2, the cover sheet 60 includes a ventral cover sheet 61 attached to the skin-facing sheet 31 of the ventral waist portion 3 from the skin-facing side Z1, and a back cover sheet 62 attached to the skin-facing sheet 41 of the back waist portion 4 from the skin-facing side Z1. The ventral cover sheet 61 has a long strip shape in the lateral direction X and is joined to the absorbent main body 10 and the skin-facing sheet 31 of the ventral waist portion 3 so as to cover the ventral edge 10F of the absorbent main body 10. The back cover sheet 62 has a long strip shape in the lateral direction X and is joined to the absorbent main body 10 and the skin-facing sheet 41 of the back waist portion 4 so as to cover the back edge 10R of the absorbent main body 10. The widths in the horizontal direction X of the ventral cover sheet 61 and the back cover sheet 62 are substantially equal to the widths in the horizontal direction X of the ventral waistline portion 3 and the back waistline portion 4, respectively, and the widths in the vertical direction Y of the ventral cover sheet 61 and the back cover sheet 62 are smaller than the widths in the vertical direction Y of the ventral waistline portion 3 and the back waistline portion 4, respectively. The ventral cover sheet 61 and the back cover sheet 62 are arranged along the waist of the wearer when connected. Hereinafter, when there is no need to particularly distinguish between the ventral cover sheet 61 and the back cover sheet 62, the ventral cover sheet 61 and the back cover sheet 62 may be collectively referred to as cover sheet 60.

[0079] The cover sheet 60 is made of, for example, polyethylene terephthalate (PET) fibers, polypropylene (PP) fibers, or mixtures thereof, rayon, fibrillated rayon, or other regenerated cellulose fibers, cotton, or natural cellulose fibers such as ground pulp, whose fiber surfaces have been hydrophilically treated. The cover sheet 60 may be a sweat-absorbent sheet having a higher water absorbency than the skin-facing sheets 31, 41 and the non-skin-facing sheets 32, 42. The high water absorbency of the cover sheet 60 allows moisture in the diaper 1 to be absorbed by the cover sheet 60, thereby preventing the diaper from becoming stuffy during wear.

[0080] 2 and 6 , the back cover sheet 62 is disposed so as to overlap at least a portion of the low-elasticity region R44 as viewed in the thickness direction Z, and covers the through-holes 50 from the skin-facing side Z1. In one embodiment, the ventral edge 62F of the back cover sheet 62 is disposed more ventrally than the back edge 10R of the absorbent main body 10, and the back edge 62R of the back cover sheet 62 is disposed more dorsally than the low-elasticity region R44. As a result, the back cover sheet 62 is disposed so as to overlap a portion of the absorbent main body 10, the first high-elasticity region R41, the second high-elasticity region R42, and the low-elasticity region R44 as viewed in the thickness direction Z. Covering the through-holes 50 with the back cover sheet 62 improves the feel of the diaper 1 against the skin and suppresses urine leakage through the through-holes 50.

[0081] The back cover sheet 62 may include an adhesive region 63 that is bonded to the absorbent main body 10 and the skin-facing sheet 41 with an adhesive, and a non-adhesive region 64 that is not bonded to the skin-facing sheet 41 with an adhesive (see FIGS. 2 and 6 ). The adhesive region 63 of the back cover sheet 62 is a region of the back cover sheet 62 that overlaps a portion of the absorbent main body 10, the first high-elasticity region R41, and the second high-elasticity region R42, when viewed from the thickness direction Z. The adhesive region 63 is bonded to a portion of the absorbent main body 10, the first high-elasticity region R41, and the second high-elasticity region R42 with a hot melt adhesive HM. The non-adhesive region 64 of the back cover sheet 62 overlaps the low-elasticity region R44 when viewed from the thickness direction Z. The non-adhesive region 64 is not bonded to the low-elasticity region R44 with the hot melt adhesive HM. Instead, the non-adhesive region 64 is pressure-bonded to the low-elasticity region R44 of the skin-facing sheet 41 by embossing. Here, when the non-adhesive region 64 of the back cover sheet 62 is pressed against the skin-facing sheet 41, the recesses or protrusions formed by embossing may be arranged along a direction inclined with respect to the waist-circumference direction R. By pressing the non-adhesive region 64 against the low-elasticity region R44 by embossing, leakage of the hot melt adhesive HM from the multiple through-holes 50 is prevented.

[0082] The cover sheet 60 may be colored a different color from the non-skin-facing sheets 32, 42. For example, the cover sheet 60 may have a color difference ΔE of 4 or more relative to the non-skin-facing sheets 32, 42 in the L*a*b* color space. The color difference ΔE is calculated using the following formula. The larger the color difference ΔE, the greater the color difference. ΔE=((L2-L1) ２ + (a2-a1) ２ + (b2-b1) ２ ) １／２ L2: L value of non-skin-facing sheets 32, 42 L1: L value of cover sheet 60 a2: a value of non-skin-facing sheets 32, 42 a1: a value of cover sheet 60 b2: b value of non-skin-facing sheets 32, 42 b1: b value of cover sheet 60

[0083] Increasing the color difference ΔE between the cover sheet 60 and the non-skin-facing sheets 32, 42 allows the colored cover sheet 60 to be seen through the multiple through-holes 50 when viewing the diaper 1 from the non-skin-facing side Z2. This improves the visibility of the multiple through-holes 50, thereby impressing on the user that the diaper 1 has high breathability. The color difference ΔE can be measured, for example, using a spectrophotometer 3nh (model number: CR8) manufactured by Shenzhen Threenh Technology Co., Ltd. For example, 10 cm x 10 cm test pieces are cut from each of ten diapers 1 and placed on a reference plate with sample number No. 502515 in a constant temperature and humidity chamber. The color difference ΔE is then measured using the spectrophotometer 3nh described above, and the average value is taken as the color difference ΔE.

[0084] Moisture-laden air within the diaper 1 is discharged to the outside through the back cover sheet 62 and the through-holes 50. The portion of the back waist portion 4 where the plurality of through-holes 50 are formed has higher breathability than other portions. For example, the airflow resistance of the first air passage P1 passing through the back cover sheet 62 and the through-holes 50 may be half or less of the airflow resistance of the second air passage P2 passing through the back cover sheet 62, the skin-facing sheet 41, and the non-skin-facing sheet 42 (see FIG. 6 ). The airflow resistance can be determined, for example, by cutting test pieces of predetermined dimensions from the back waist portion 4 of three diapers 1, measuring the airflow resistance of each of the three test pieces using a Kato Tech Co., Ltd. air permeability tester (KES-F8) or an equivalent air permeability tester, and calculating the average value.

[0085] When putting the diaper 1 on a wearer, the wearer first places both legs through the waist opening BH and the pair of leg openings LH, and then pulls up the diaper 1. This positions the waist section 2 around the wearer's waist, and positions the crotch section 10c of the absorbent main body 10 so as to cover the wearer's crotch. Since the multiple through-holes 50 formed in the back waist section 4 are positioned on the back side of the wearer, moisture, including sweat, from the wearer is expelled to the outside of the diaper 1 through the back cover sheet 62 and the multiple through-holes 50. This prevents the diaper 1 from becoming stuffy. In particular, since the multiple through-holes 50 are formed in the low-stretch region R44, which has low stretchability, the multiple through-holes 50 are prevented from closing due to contraction of the multiple elastic members 43. As a result, air can enter and exit through the multiple through-holes 50, improving the breathability of the diaper 1.

[0086] Next, a method for manufacturing the diaper 1 described above will be described with reference to Figures 8 and 9. Figure 8 is a flowchart showing a method for manufacturing the diaper 1 according to one embodiment. Figure 9 is a schematic diagram showing an exemplary manufacturing apparatus 100 to which the method for manufacturing the diaper 1 according to one embodiment can be applied. This diaper manufacturing method continuously manufactures the diaper 1 described above by carrying out each of the steps described below. In the following description, the terms "upstream" and "downstream" are used with reference to the conveying direction CD, which will be described later.

[0087] As shown in Figure 8, the manufacturing apparatus 100 includes a conveying roller 102, an elastic member supply device 104, a coater 106, a joining roller 108, an absorbent body supply device 110, a perforation roller 112, a cover sheet supply device 114, an embossing roller 116, and a cutting device 118.

[0088] In one embodiment of the method for manufacturing a pet diaper, first, the conveying rollers 102 convey the skin-contact strip 141, which is the skin-contact sheet 41 of the diaper 1 that is continuous in the conveying direction CD, and the non-skin-contact strip 142, which is the non-skin-contact strip 42 that is continuous in the conveying direction CD, in the conveying direction CD (step ST1). The conveying direction CD in which the skin-contact strip 141 and the non-skin-contact strip 142 are conveyed is a direction along the lateral direction X of the diaper 1.

[0089] Next, the elastic member supplying device 104 supplies a plurality of elastic members 43 onto the strip-shaped non-skin-facing sheet 142 (step ST2). The plurality of elastic members 43 are arranged on the strip-shaped non-skin-facing sheet 142 along the conveying direction CD. Next, the coater 106 applies hot melt adhesive to the plurality of elastic members 43 (step ST3). As shown in FIG. 10( a), the coater 106 also applies hot melt adhesive to a planned bonding region 150 of the strip-shaped non-skin-facing sheet 142 (step ST4). The planned bonding region 150 is an area where a plurality of through holes 50 will be formed in a subsequent process. Meanwhile, the coater 106 does not apply hot melt adhesive to areas of the strip-shaped non-skin-facing sheet 142 other than the planned bonding region 150.

[0090] Next, the joining roller 108 presses the strip-shaped skin-face sheet 141 and the strip-shaped non-skin-face sheet 142 in the thickness direction. This forms a joined sheet 140 in which the strip-shaped skin-face sheet 141 and the strip-shaped non-skin-face sheet 142 are joined to each other via the multiple elastic members 43 (step ST5). At this time, the strip-shaped non-skin-face sheet 142 and the strip-shaped non-skin-face sheet 142 are directly bonded to each other in the intended bonding region 150. Meanwhile, in regions other than the intended bonding region 150, the strip-shaped non-skin-face sheet 142 and the strip-shaped non-skin-face sheet 142 are bonded to each other via the multiple elastic members 43 to which adhesive is applied.

[0091] Next, the absorbent main body supply device 110 arranges a plurality of absorbent main bodies 10 on the joining sheet 140 downstream of the joining roller 108 (step ST6). The plurality of absorbent main bodies 10 are arranged on the joining sheet 140 at predetermined intervals in the conveyance direction CD. Hot melt adhesive is continuously applied to the back side portion 10b of the absorbent main body 10 along the conveyance direction CD, and the back side portion 10b is adhered to the joining sheet 140.

[0092] Next, the perforation roller 112 forms a plurality of through holes 50 in the bonded sheet 140 downstream of the absorbent body supply device 110 (step ST7). As shown in FIG. 8 , the perforation roller 112 is equipped with a plurality of first cutters 112A for forming the plurality of through holes 50. The plurality of first cutters 112A form the plurality of through holes 50 in the bonded region 150 by cutting and cutting out portions of the strip-shaped skin-face sheet 141 and the strip-shaped non-skin-face sheet 142 in the bonded region 150. At this time, since the strip-shaped skin-face sheet 141 and the strip-shaped non-skin-face sheet 142 are directly bonded in the bonded region 150, peeling of the strip-shaped skin-face sheet 141 and the strip-shaped non-skin-face sheet 142 is prevented. As described above, the plurality of through holes 50 are formed in the bonded sheet 140 from the skin-face side Z1.

[0093] By forming the plurality of through holes 50 in the bonding sheet 140, the plurality of elastic members 43 are cut by the plurality of first cutters 112A in the intended bonding region 150. The perforation roller 112 may be disposed adjacent to the plurality of first cutters 112A and include suction ports connected to a suction device (not shown). Some of the plurality of elastic members 43 cut during the formation of the plurality of through holes 50 are sucked through the suction ports and removed from the bonding sheet 140. As a result, as shown in FIG. 10( b), the bonding sheet 140 is formed with a first high-elasticity region R41, a second high-elasticity region R42, a third high-elasticity region R43, and a low-elasticity region R44. That is, the region where the plurality of through holes 50 are formed in the intended bonding region 150 of the bonding sheet 140 and the plurality of elastic members 43 are removed becomes the low-elasticity region R44.

[0094] Next, the perforation roller 112 makes slits 152 in the low-elasticity region R44 of the bonding sheet 140 along a direction perpendicular to the conveyance direction CD (step ST8). As shown in FIG. 8, the perforation roller 112 is equipped with a second cutter 112B for making the slits 152. The second cutter 112B makes slit-shaped slits 152 along a direction perpendicular to the conveyance direction CD, cutting the multiple elastic members 43 remaining in the low-elasticity region R44. This more reliably reduces the elasticity of the low-elasticity region R44. The slits 152 may be formed simultaneously with the multiple through-holes 50.

[0095] Next, the cover sheet supply device 114 places the cover sheet 60 on the bonding sheet 140 downstream of the perforation roller 112 (step ST9). Hot melt adhesive is applied to a portion of the cover sheet 60. The adhesive regions of the cover sheet 60 to which the hot melt adhesive is applied are adhered to the first high-elasticity region R41, the second high-elasticity region R42, and the third high-elasticity region R43 of the bonding sheet 140. Meanwhile, the non-adhesive regions of the cover sheet 60 to which the hot melt adhesive is not applied are placed on the low-elasticity region R44 of the bonding sheet 140.

[0096] Next, the embossing roller 116 embosses the bonding sheet 140 downstream of the cover sheet supply device 114 (step ST10). The embossing is performed by compressing the non-adhesive region of the cover sheet 60 and the low-elasticity region R44 of the bonding sheet 140 with the embossing roller 116, which has a plurality of protrusions. This embossing causes the non-adhesive region of the cover sheet 60 to be pressed against the low-elasticity region R44 of the bonding sheet 140.

[0097] Next, the cutting device 118 cuts the bonded sheet 140 at predetermined intervals in the conveyance direction CD. As a result, the diaper 1 is manufactured, which includes the waist portion 2 and the absorbent main body 10, each having a first high-elasticity region R41, a second high-elasticity region R42, a third high-elasticity region R43, and a low-elasticity region R44. The low-elasticity region R44 of the diaper 1 manufactured as described above has a plurality of through-holes 50 formed therein, thereby providing the diaper 1 with high breathability.

[0098] While the diaper 1 according to various embodiments has been described above, the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit of the invention. In other words, it should be noted that the above-described embodiments are for illustrative purposes only and do not limit the scope of the present invention. The above-described various embodiments can be combined within a consistent range.

[0099] For example, in the above embodiment, a plurality of through holes 50 are formed in the low-elasticity region R44 of the back-side waistline portion 4, but it is sufficient that at least one through hole 50 is formed in the back-side waistline portion 4. Furthermore, it is sufficient that the through hole 50 is formed in at least one of the ventral waistline portion 3 and the back-side waistline portion 4. For example, one or more through holes 50 may be formed only in the low-elasticity region R34 of the ventral waistline portion 3, or one or more through holes 50 may be formed in both the low-elasticity region R34 of the ventral waistline portion 3 and the low-elasticity region R44 of the back-side waistline portion 4.

[0100] In the embodiment shown in Fig. 2, the cover sheet 60 is attached to the skin-facing sheets 31, 41 of the waistline portion 2 from the skin-facing side Z1, but the cover sheet 60 does not have to be attached to the skin-facing sheets 31, 41 as long as it is attached to the waistline portion 2 so as to overlap the through-hole 50 when viewed from the thickness direction Z. For example, the cover sheet 60 may be attached to the non-skin-facing sheets 32, 42 from the non-skin-facing side Z2 so as to cover the through-hole 50. The cover sheet 60 may also be disposed between the skin-facing sheet 31 and the non-skin-facing sheet 32, and between the skin-facing sheet 41 and the non-skin-facing sheet 42. Even in such cases, providing the cover sheet 60 so as to overlap the through-hole 50 can prevent urine leakage from the through-hole 50.

[0101] The present disclosure includes the following: [1] A pants-type disposable diaper comprising: an absorbent main body including a abdominal portion located on the abdominal side of a wearer when worn, a dorsal portion located on the dorsal side of the wearer, and a crotch portion disposed between the abdominal portion and the dorsal portion, and extending in a longitudinal direction between the abdominal portion and the dorsal portion when worn; a waist portion joined to the abdominal portion and the dorsal portion and extending in a waist direction of the wearer, the waist portion including a skin-facing sheet disposed on the skin-facing side, a non-skin-facing sheet disposed on the non-skin-facing side, and a plurality of elastic members disposed between the skin-facing sheet and the non-skin-facing sheet, wherein the waist portion includes a stretchable region that can stretch in the waist direction in accordance with stretching of the plurality of elastic members, and a low-stretch region having lower stretchability than that of the stretchable region, the low-stretch region having a through-hole that penetrates the waist portion in the thickness direction, and the skin-facing sheet and the non-skin-facing sheet in the low-stretch region being directly joined to each other at least around the through-hole.

[0102] [2] The pants-type disposable diaper according to [1], wherein the skin-facing sheet and the non-skin-facing sheet are directly bonded to each other with an adhesive throughout the entire low-elasticity region.

[0103] [3] The pants-type disposable diaper according to [1] or [2], wherein the skin-facing sheet and the non-skin-facing sheet in the stretchable region have non-adhesive regions between the plurality of elastic members that are not directly adhered to each other.

[0104] [4] The pants-type disposable diaper according to any one of [1] to [3], further comprising a cover sheet attached to the waist portion so as to overlap the through-hole when viewed in the thickness direction.

[0105] [5] The pants-type disposable diaper according to [4], wherein the cover sheet is attached to the skin-facing sheet from the skin-facing side so as to cover the through-holes.

[0106] [6] The pants-type disposable diaper according to [4], wherein the cover sheet is attached to the non-skin-facing sheet from the non-skin-facing side so as to cover the through-holes.

[0107] [7] The pants-type disposable diaper according to [4], wherein the cover sheet is disposed between the skin-facing sheet and the non-skin-facing sheet.

[0108] [8] The pants-type disposable diaper according to [5], wherein the cover sheet includes an adhesive region that is adhered to the skin-facing sheet with an adhesive and a non-adhesive region that is not adhered to the skin-facing sheet with an adhesive, and when viewed in the thickness direction of the waistband, the adhesive region overlaps at least a portion of the stretch region, and the non-adhesive region overlaps the low-stretch region.

[0109] [9] The pants-type disposable diaper according to [8], wherein the non-adhesive region of the cover sheet is pressure-bonded to the skin-facing sheet by embossing.

[0110]

[10] The pants-type disposable diaper according to [9], wherein the recesses or protrusions formed by the embossing are arranged in a direction inclined with respect to the waist circumference direction.

[0111]

[11] The pants-type disposable diaper according to any one of [1] to

[10] , wherein the contour line of the through-hole is a smooth curve having a continuous curvature.

[0112]

[12] The pants-type disposable diaper according to

[11] , wherein the contour line of the through-hole has a radius of curvature of 2.5 mm or more.

[0113]

[13] The pants-type disposable diaper according to any one of [1] to

[12] , wherein the ventral side portion and the dorsal side portion of the absorbent main body are adhered to the skin-facing sheet of the waist portion via an adhesive layer, and the adhesive layer extends continuously in the waist direction.

[0114]

[14] A method for manufacturing a pants-type disposable diaper having a waistline portion including a skin-facing sheet arranged on the skin-facing side, a non-skin-facing sheet arranged on the non-skin-facing side, and a plurality of elastic members arranged between the skin-facing sheet and the non-skin-facing sheet, the method comprising the steps of: applying adhesive to the plurality of elastic members; arranging the plurality of elastic members, to which the adhesive has been applied, along the conveyance direction between a strip-shaped skin-facing sheet in which the skin-facing sheet is continuous in the conveyance direction and a strip-shaped non-skin-facing sheet in which the non-skin-facing sheet is continuous in the conveyance direction, to form a joined sheet in which the strip-shaped skin-facing sheet and the strip-shaped non-skin-facing sheet are joined to each other via the plurality of elastic members; cutting some of the plurality of elastic members while forming through-holes that pass through the joined sheet in the thickness direction, to form in the joined sheet high-elasticity regions that can stretch in the conveyance direction and low-elasticity regions that have elasticity lower than that of the high-elasticity regions; and cutting the joined sheet at predetermined intervals in the conveyance direction to form the waistline portion including the high-elasticity regions and the low-elasticity regions.

[0115]

[15] The method according to

[14] , further comprising the step of removing by suction some of the elastic members cut when the through holes are formed.

[0116]

[16] The method according to

[14] or

[15] , further comprising a step of making a slit in the low-elasticity region of the joined sheet along a direction perpendicular to the conveying direction.

[0117]

[17] The method according to any one of

[14] to

[16] , further comprising the step of applying adhesive to the intended bonding area of ​​the strip-shaped skin-face sheet or the strip-shaped non-skin-face sheet before forming the through hole, thereby directly bonding the strip-shaped skin-face sheet and the strip-shaped non-skin-face sheet to each other in the intended bonding area, wherein the through hole is formed in the joining sheet so as to pass through the intended bonding area.

[0118]

[18] The method according to any one of

[14] to

[17] , comprising the steps of: placing a cover sheet on the strip-shaped skin sheet of the joining sheet so as to cover the through-hole; adhering the cover sheet to the high-elasticity region of the joining sheet with an adhesive; and pressing the cover sheet to the low-elasticity region of the joining sheet by embossing.

[0119] 1...pants-type disposable diaper, 2...waist portion, 10a...abdominal portion, 10b...dorsal portion, 10c...crotch portion, 31, 41...skin-facing sheet, 32, 42...non-skin-facing sheet, 33, 43...elastic member, 50...through hole, 60...cover sheet, 63...adhesive region, 64...non-adhesive region, 140...bonding sheet, 141...strip-shaped skin-facing sheet, 142...strip-shaped non-skin-facing sheet, 150...proposed adhesive region, 152...slit, CD...conveyance direction, L...longitudinal direction, R...waist direction, R34, R44...low-elasticity region, Z1...skin-facing side, Z2...non-skin-facing side.

Claims

1. A pants-type disposable diaper comprising: an absorbent main body including a abdominal portion located on the abdominal side of a wearer when worn, a dorsal portion located on the dorsal side of the wearer, and a crotch portion located between the abdominal portion and the dorsal portion, and extending longitudinally between the abdominal portion and the dorsal portion when worn; and a waist portion joined to the abdominal portion and the dorsal portion and extending in the waist direction of the wearer, the waist portion including a skin-facing sheet located on the skin-facing side, a non-skin-facing sheet located on the non-skin-facing side, and a plurality of elastic members located between the skin-facing sheet and the non-skin-facing sheet, wherein the waist portion includes a stretchable region that can stretch in the waist direction in accordance with the stretching of the plurality of elastic members, and a low-stretch region having lower stretchability than that of the stretchable region, the low-stretch region having a through-hole that passes through the waist portion in the thickness direction, and the skin-facing sheet and the non-skin-facing sheet in the low-stretch region being directly joined to each other at least around the through-hole.

2. The pants-type disposable diaper according to claim 1, wherein the skin-facing sheet and the non-skin-facing sheet are directly bonded to each other with an adhesive throughout the entire low-elasticity region.

3. The pants-type disposable diaper according to claim 1, wherein the skin-facing sheet and the non-skin-facing sheet in the stretchable region have non-adhesive regions between the plurality of elastic members where they are not directly adhered to each other.

4. The pants-type disposable diaper according to claim 1, further comprising a cover sheet attached to the waistband portion so as to overlap the through-hole when viewed in the thickness direction.

5. The pants-type disposable diaper according to claim 4, wherein the cover sheet is attached to the skin-facing sheet from the skin-facing side so as to cover the through-holes.

6. The pants-type disposable diaper according to claim 4, wherein the cover sheet is attached to the non-skin-facing sheet from the non-skin-facing side so as to cover the through-hole.

7. The pants-type disposable diaper according to claim 4, wherein the cover sheet is disposed between the skin-facing sheet and the non-skin-facing sheet.

8. A pants-type disposable diaper as described in claim 5, wherein the cover sheet includes an adhesive region that is adhered to the skin-facing sheet with an adhesive and a non-adhesive region that is not adhered to the skin-facing sheet with an adhesive, and when viewed in the thickness direction of the waistband portion, the adhesive region overlaps at least a portion of the stretch region, and the non-adhesive region overlaps the low-stretch region.

9. The pants-type disposable diaper according to claim 8, wherein the non-adhesive areas of the cover sheet are pressed onto the skin-facing sheet by embossing.

10. The pants-type disposable diaper according to claim 9, wherein the recesses or protrusions formed by the embossing are arranged in a direction inclined relative to the waist circumference direction.

11. The pants-type disposable diaper according to claim 1, wherein the contour line of the through-hole is a smooth curve having a continuous curvature.

12. The pants-type disposable diaper according to claim 11, wherein the contour line of the through-hole has a radius of curvature of 2.5 mm or more.

13. The pants-type disposable diaper according to claim 1, wherein the ventral side and back side of the absorbent main body are adhered to the skin-facing sheet of the waist area via an adhesive layer, and the adhesive layer extends continuously in the waist area direction.

14. A method for manufacturing pants-type disposable diapers having a waistline including a skin-facing sheet arranged on the skin-facing side, a non-skin-facing sheet arranged on the non-skin-facing side, and a plurality of elastic members arranged between the skin-facing sheet and the non-skin-facing sheet, the method comprising the steps of: applying adhesive to the plurality of elastic members; arranging the plurality of elastic members, to which the adhesive has been applied, along the conveyance direction between a strip-shaped skin-facing sheet in which the skin-facing sheet is continuous in the conveyance direction and a strip-shaped non-skin-facing sheet in which the non-skin-facing sheet is continuous in the conveyance direction, to form a joined sheet in which the strip-shaped skin-facing sheet and the strip-shaped non-skin-facing sheet are joined to each other via the plurality of elastic members; cutting some of the plurality of elastic members while forming through-holes that pass through the joined sheet in the thickness direction, to form in the joined sheet high-stretch regions that can stretch in the conveyance direction and low-stretch regions that have lower stretchability than the high-stretch regions; and cutting the joined sheet at predetermined intervals in the conveyance direction to form the waistline including the high-stretch regions and the low-stretch regions.

15. The method according to claim 14, further comprising the step of removing by suction the portions of the plurality of elastic members that are cut when the through holes are formed.

16. The method according to claim 14, further comprising the step of making slits in the low-elasticity region of the bonded sheet along a direction perpendicular to the conveying direction.

17. The method according to claim 14, further comprising the step of applying adhesive to the intended bonding area of ​​the strip-shaped skin-face sheet or the strip-shaped non-skin-face sheet before forming the through hole, thereby directly bonding the strip-shaped skin-face sheet and the strip-shaped non-skin-face sheet to each other in the intended bonding area, and the through hole is formed in the joining sheet so as to pass through the intended bonding area.

18. The method according to claim 14, comprising the steps of: placing a cover sheet on the strip-shaped skin sheet of the joining sheet so as to cover the through-hole; adhering the cover sheet to the high-stretch area of ​​the joining sheet with an adhesive; and pressing the cover sheet to the low-stretch area of ​​the joining sheet by embossing.

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