GB2560470A

GB2560470A - Disposable diaper

Info

Publication number: GB2560470A
Application number: GB1809270.0A
Authority: GB
Inventors: Kajiwara Jun; Koyama Izumi; Fukuda Yuko; Okuda Yasuyuki
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2015-12-22
Filing date: 2016-11-30
Publication date: 2018-09-12
Anticipated expiration: 2036-11-30
Also published as: DE112016005877T5; RU2676993C1; CN108366886B; WO2017110395A1; JP6208208B2; GB201809270D0; JP2017113187A; GB2560470B; CN108366886A

Abstract

This disposable diaper (1) has abdominal waist flaps (FA) and back waist flaps (FB) located to the outside of the front and back ends (23A, 23B) in the longitudinal direction (X) of an absorbent (23) and extending in the transverse direction (Y). The back waist flaps (FB) have a hydrophobic skin-side sheet (4) and a hydrophilic non-skin-side sheet (5). The skin-side sheet (4) is provided with depressions (41) that form hollows toward the non-skin-side sheet (5) and openings (44) in the depressions (41) that pass through to the skin-side sheet (4). The thickness of the depressions (41) of the skin-side sheet (4) is smaller closer to the openings (44).

Description

(54) Title of the Invention: Disposable diaper Abstract Title: Disposable diaper (57) This disposable diaper (1) has abdominal waist flaps (FA) and back waist flaps (FB) located to the outside of the front and back ends (23A, 23B) in the longitudinal direction (X) of an absorbent (23) and extending in the transverse direction (Y). The back waist flaps (FB) have a hydrophobic skin-side sheet (4) and a hydrophilic non-skin-side sheet (5). The skin-side sheet (4) is provided with depressions (41) that form hollows toward the non-skin-side sheet (5) and openings (44) in the depressions (41) that pass through to the skin-side sheet (4). The thickness of the depressions (41) of the skin-side sheet (4) is smaller closer to the openings (44).

Y

1/5

FIG. 1

CL1 B

Y

2/5

FIG. 2

Ο ,3T1 ο 3a1 ·, Ρ

X

A

Β

23Β

3/5

FIG. 3(a)

FIG. 3(b)

4/5

FIG. 4

5/5

DESCRIPTION

Title of Invention: DISPOSABLE DIAPER

Technical Field [0001]

The present invention relates to a disposable diaper.

Background Art [0002]

Conventionally, there is a known disposable diaper whose surface that comes into contact with skin is provided with a sheet or the like for absorbing sweat, thereby effectively preventing eczema, heat rashes, rashes, and the like (Patent Literature 1, for example).

[0003]

Patent Literature 1 discloses a disposable diaper whose end flaps and side flaps are provided with a composite sheet in which a hydrophobic first fiber nonwoven fabric on the skin-facing surface and a hydrophilic second fiber nonwoven fabric on the non-skinfacing surface are laminated and fixed to each other at fusion bonded portions, in order to absorb sweat. Furthermore, Patent Literature 1 describes that a large number of openings are formed through the first fiber nonwoven fabric of the composite sheet.

[0004]

As another technique, the applicant of the present invention previously proposed a pull-on disposable diaper whose outer cover is formed of tubular portions extending in the longitudinal direction and successively arranged along the width direction, and a plurality of openings that are in communication with the inside of the tubular portions are intermittently formed along the longitudinal direction in projections of a sheet forming the tubular portions and arranged on the skin-contacting surface side (Patent Literature 2, for example).

Citation List

Patent Literatures [0005]

Patent Literature 1: JP 2004-298467A

Patent Literature 2: JP 2011-78477A

Summary of Invention [0006]

The present invention is directed to a disposable diaper comprising, in a longitudinal direction, a front region, a rear region, and a crotch region positioned between the front region and the rear region, having an absorbent member spanning from the front region to the rear region, and having a front waist flap and a rear waist flap extending in a lateral direction and positioned outward of front and rear end portions, respectively, in the longitudinal direction of the absorbent member. At least the rear waist flap has a hydrophobic skin-side sheet that forms a skin-contacting surface, and a hydrophilic nonskin-side sheet that is positioned on a non-skin-facing surface side of the skin-side sheet. The skin-side sheet includes a plurality of depressed portions depressed toward the nonskin-side sheet, and openings formed through the skin-side sheet respectively in the depressed portions. Each depressed portion of the skin-side sheet has a thickness that becomes smaller toward the opening.

Brief Description of Drawings [0007] [FIG. 1] FIG. 1 is a perspective view showing a pull-on disposable diaper in a natural state according to an embodiment of the present invention.

[FIG. 2] FIG. 2 is an unfolded plan view of the diaper shown in FIG. 1 in its flat-out, uncontracted state, viewed from the skin-contacting surface side.

[FIG. 3] FIG. 3(a) is an enlarged plan view of a main portion of a part of an outer cover of the diaper shown in FIG. 2, viewed from the skin-contacting surface side, and FIG. 3(b) is an enlarged plan view of a part of a depressed portion shown in FIG. 3(a).

[FIG. 4] FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. 2.

[FIG. 5] FIG. 5 is a perspective view showing an exploded state of a part of the outer cover of the diaper shown in FIG. 2.

[FIG. 6] FIG. 6 is an enlarged cross-sectional view showing a cross-section taken along the lateral direction (Y direction) of a waist elasticized portion in the diaper shown in FIG. 1.

Description of Embodiments [0008]

The disposable diaper disclosed in Patent Literature 1 is such that fusion bonded portions are formed while maintaining the fiber form of their constituent fibers in order to shift sweat therefrom as well through capillary action. If fusion bonded portions are formed while maintaining the fiber form of their constituent fibers in this manner, the thickness of peripheral edges of the fusion bonded portions cannot be sufficiently thin, the capillary action is unstable, and thus sweat cannot be sufficiently absorbed via the openings.

[0009]

Furthermore, Patent Literature 2 has no mention of the thickness of peripheral edges of the openings formed through the outer cover.

[0010]

The present invention relates to a disposable diaper that can solve the abovementioned problems in the related art.

[0011]

Hereinafter, the present invention will be described with reference to the drawings on the basis of preferred embodiments thereof.

The disposable diaper of the present invention includes, along a longitudinal direction X, a front region A, a rear region B, and a crotch region C that is positioned between the front region A and the rear region B, has an absorbent member 23 spanning from the front region A to the rear region B, and has a front waist flap FA and a rear waist flap FB extending in the lateral direction Y and positioned outward of front and rear ends 23 A and 23B, respectively, in the longitudinal direction X of the absorbent member 23. The front region A is a region that is worn about a front side of a wearer when the disposable diaper is worn, and the rear region B is a region that is worn about a rear side of the wearer when the disposable diaper is worn. The front waist flap FA refers to a region obtained by adding a region extending in the lateral direction Y and positioned outward in the longitudinal direction X from an edge of the front end 23 A on the front region A side in the longitudinal direction X of the absorbent member 23 and regions extending in the lateral direction Y from the front end 23 A on the front region A side in the longitudinal direction X of the absorbent member 23. Furthermore, the rear waist flap FB refers to a region obtained by adding a region extending in the lateral direction Y and positioned outward in the longitudinal direction X from an edge of the rear end 23B on the rear region B side in the longitudinal direction X of the absorbent member 23 and regions extending in the lateral direction Y from the rear end 23B on the rear region B side in the longitudinal direction X of the absorbent member 23.

[0012]

FIGS. 1 and 2 show a pull-on disposable diaper 1 (hereinafter, alternatively referred to as a “diaper 1”) that is a disposable diaper according to an embodiment of the present invention. As shown in FIGS. 1 and 2, the diaper 1 includes an absorbent assembly 2, and an outer cover 3 that is arranged on the non-skin-facing surface side of the absorbent assembly 2 and fixes the absorbent assembly 2. The outer cover 3 has the front waist flap FA and the rear waist flap FB extending in the lateral direction Y and positioned outward of the front and rear ends 23 A and 23B, respectively, in the longitudinal direction X of the absorbent member 23 forming the absorbent assembly 2. The diaper 1 is a disposable diaper in which both lateral side edges 3al,3al of the front region A of the outer cover 3 and both lateral side edges 3bl,3bl of the rear region B of the outer cover 3 are joined to each other, and form a pair of side seals S,S, a waist opening WO, and a pair of leg openings LO,LO. Preferably, as shown in FIG. 2, in plan view of the diaper 1 in its flat-out, uncontracted state, the outer cover 3 is divided into the front region A that is worn about a front side of a wearer when worn, the rear region B that is worn about a rear side of the wearer when worn, and the crotch region C that is positioned between the front region A and the rear region B.

[0013]

The above-described flat-out, uncontracted state of the diaper 1 is, as shown in FIG. 2, a state in which the side seals S are peeled away so that the diaper 1 is in a flat-out state, elastic members at respective portions of the diaper 1 in the flat-out state are uncontracted so that the dimensions of the diaper matches its design dimensions (that is the same as the dimensions when the diaper 1 is spread out in a planar shape while completely eliminating the influence of the elastic members).

[0014]

In this specification, “skin-contacting surface” refers to a surface of the diaper 1 or a constituent element thereof (e.g., the outer cover 3) that is in contact with the skin of the wearer when the diaper 1 is worn. Furthermore, “skin-facing surface” is a surface of the diaper 1 or a constituent element thereof that faces the skin of the wearer when the diaper 1 is worn, and “non-skin-facing surface” is a surface of the diaper 1 or a constituent element thereof that faces the side opposite to the skin of the wearer (clothing side) when the diaper 1 is worn. In the diaper 1, the longitudinal direction (X direction) is a direction from the front region A to the rear region B in plan view of the diaper 1 in its flat-out, uncontracted state. Furthermore, the lateral direction (Y direction) is a direction that is orthogonal to the longitudinal direction (X direction) and is the width direction of the diaper 1 in plan view of the diaper 1 in its flat-out, uncontracted state.

Furthermore, the diaper 1 is bilaterally symmetric about a longitudinal center line CL1 extending in the longitudinal direction (X direction) shown in FIG. 2. ACL2 in FIG.

is a lateral center line extending in the lateral direction (Y direction) and dividing the diaper 1 into two halves, and is orthogonal to the longitudinal center line CL1.

[0015]

In the diaper 1, as shown in FIG. 2, the absorbent assembly 2 has an oblong shape that is relatively oblong in the longitudinal direction (X direction) in the flat-out, uncontracted state of the diaper 1. The absorbent assembly 2 includes a liquid permeable topsheet 21 that forms the skin-facing surface, a sparingly liquid permeable (or water repellent) backsheet 22 that forms the non-skin-facing surface, and a liquid-retentive absorbent member 23 that is positioned between the sheets 21 and 22. Furthermore, as shown in FIG. 2, leak-proof cuffs 24,24 having leak-proof cuff forming elastic members 25 arranged in a state of being stretched in the longitudinal direction (X direction) are provided on both sides along the longitudinal direction (X direction) of the absorbent assembly 2. Specifically, the leak-proof cuffs 24 are made of a liquid impermeable or water repellent and air permeable material, and the leak-proof cuff forming elastic members 25 are arranged in a state of being stretched in the longitudinal direction (X direction), near free ends of the leak-proof cuffs 24. When the diaper is worn, the free ends of the leak-proof cuffs 24 stand up due to contraction of the leak-proof cuff forming elastic members 25, thereby preventing a bodily fluid from flowing out in the lateral direction (Y direction).

[0016]

As shown in FIG. 2, the thus configured absorbent assembly 2 is joined to the middle of the outer cover 3 using an assembly fixing adhesive such that the longitudinal direction (X direction) of the absorbent assembly 2 matches the longitudinal direction (X direction) of the diaper 1 in its flat-out, uncontracted state. In this manner, the outer cover is arranged on and adhesively fixed to the non-skin-facing surface side of the backsheet 22 forming the absorbent assembly 2 in the thickness direction of the disposable diaper 1. Accordingly, in the diaper 1, the absorbent member 23 forming the absorbent assembly 2 is arranged spanning from the front region Ato the rear region B.

[0017]

At least the rear waist flap FB of the front waist flap FA and the rear waist flap FB extending in the lateral direction Y and positioned outward of the front and rear ends 23 A and 23B, respectively, in the longitudinal direction X of the absorbent member 23 includes a hydrophobic skin-side sheet 4 that forms the skin-contacting surface, and a hydrophilic non-skin-side sheet 5 that is positioned on a non-skin-facing surface side of the skin-side sheet 4. As shown in FIG. 2, in the diaper 1, the front waist flap FA and the rear waist flap FB have a skin-side sheet 4 and the non-skin-side sheet 5, and further have a hydrophobic outer sheet 6 on the non-skin-facing surface side of the non-skin-side sheet 5.

[0018]

Preferably, as shown in FIG. 2, in the diaper 1, the outer cover 3 includes the front waist flap FA and the rear waist flap FB extending in the lateral direction Y and positioned outward of the front and rear ends 23 A and 23B, respectively, in the longitudinal direction X of the absorbent member 23. As shown in FIGS. 2 and 4, the outer cover 3 includes the outer sheet 6 on the non-skin-facing surface side that forms the outer face of the diaper 1, skin-side sheets 4 on the side that is closest to the skin-facing surface, and an inner sheet that is positioned between the outer sheet 6 and the skin-side sheet 4. In the diaper 1, the inner sheet corresponds to the non-skin-side sheet 5.

[0019]

More preferably, as shown in FIG. 2, in the diaper 1, the sheet material forming the outer sheet 6 in both the front region A and the rear region B is folded back toward the skin-facing surface of the non-skin-side sheet 5 along the peripheral edges of the waist openings WO, and the folded-back portions 6R cover the front and rear ends 23 A and 23B in the longitudinal direction (X direction) of the absorbent member 23 forming the absorbent assembly 2. The skin-side sheets 4, the non-skin-side sheet (inner sheet) 5, and the outer sheet 6 may be separate sheets, but, in the diaper 1, the skin-side sheets 4 are formed of the folded-back portions 6R of the outer sheet 6. In this manner, in the diaper 1, the skin-side sheets 4 are arranged on the skin-facing surface side of the non-skin-side sheet 5 in the rear waist flap FB and the front waist flap FA. As shown in FIG. 2, in the diaper 1, the outer sheet 6 other than the folded-back portions 6R and the non-skin-side sheet 5 are inwardly narrowed toward the longitudinal center line CL1 at the middle in the longitudinal direction (X direction), and are formed so as to have the same shape and the same size. The skin-side sheets 4 formed of the folded-back portions 6R of the outer sheet 6 are each formed in the shape of a rectangle that is elongated in the lateral direction (Y direction).

[0020]

As shown in FIG. 4, the skin-side sheets 4 include a plurality of depressed portions 41 depressed toward the non-skin-side sheet 5, and openings 44 formed through the skinside sheets 4 respectively in the depressed portions 41. In the diaper 1, the skin-side sheets 4 include bonded portions 42 in which constituent fibers of the skin-side sheets 4 are bonded to each other, in the respective depressed portions 41. The bonded portions 42 include portions in which constituent fibers of the skin-side sheets 4 are melted and bonded to each other with no gap therebetween. The portions that are bonded refer to portions in which constituent fibers are melted with no gap therebetween to the extent that the constituent fibers do not return to their original fiber shape even when peeled away from the portions that are bonded. The portions that are bonded are liquid impermeable portions that do not allow liquids to pass therethrough. In the bonded portions 42 of the diaper 1, the portions that are bonded are in the shape of a film. As shown in FIGS. 3 and 4, in the diaper 1, the openings 44 are formed inside the bonded portions 42.

[0021]

In order to improve the sweat absorbing properties, the openings 44 (the bonded portions 42 in which the openings 44 are arranged) are arranged in the skin-side sheets 4, preferably at least on the side positioned outward in the longitudinal direction X of the edge of the rear end 23B (on the side opposite to the lateral center line CL2) in the longitudinal direction (X direction) of the absorbent member 23 forming the absorbent assembly 2, and, in the diaper 1, the openings 44 are intermittently arranged throughout the skin-side sheets as shown in FIG. 2. Preferably, the bonded portions 42 in which the openings 44 are arranged are intermittently arranged in a row along the longitudinal direction (X direction), and a plurality of bonded portion rows 42L formed of the plurality of bonded portions 42 are arranged at intervals along the lateral direction (Y direction). In order to improve the sweat dispersing properties, as shown in FIGS. 2 and 3, the bonded portions 42 in which the openings 44 are arranged are preferably arranged at positions that do not overlap joined regions 8, which will be described later, and, in the diaper 1, the bonded portion rows 42L and later-described joined region rows 8L formed of the plurality of joined regions 8 are alternately arranged in the lateral direction (Y direction).

[0022]

The bonded portions 42 in which the openings 44 are arranged can be formed by heat embossing only the skin-side sheets 4 and heating the skin-side sheets 4 until openings are formed therethrough. The heat embossing apparatus may be an apparatus including an embossing roller and an anvil roller, wherein the outer peripheral face of the embossing roller has a projection that conforms to the bonded portions 42. As processing for forming the bonded portions 42, ultrasonic sealing, a laser, and the like may be used instead of heat embossing. When forming the bonded portions 42 in which the openings 44 are arranged through heat embossing, the embossing intensity when forming the bonded portions 42 is preferably higher than the embossing intensity when forming the joined regions 8, which will be described later.

[0023]

In order to improve the sweat absorbing properties and not to allow sweat to return from the non-skin-side sheet 5 to the skin, in plan view of the diaper 1 in its flat-out, uncontracted state as shown in FIG. 2, the interval between the bonded portions 42,42 that are adjacent to each other in the longitudinal direction (X direction) forming the bonded portion rows 42F extending in the longitudinal direction (X direction) is preferably 1 mm or greater, and more preferably 3 mm or greater, is preferably 20 mm or less, and more preferably 18 mm or less, and, specifically, is preferably from 1 to 20 mm, and more preferably from 3 to 18 mm.

Furthermore, in order to improve the sweat dispersing properties, in plan view of the diaper 1 in its flat-out, uncontracted state as shown in FIG. 2, the interval between the bonded portion rows 42L,42L that are adjacent to each other in the lateral direction (Y direction) is preferably 4 mm or greater, and more preferably 6 mm or greater, is preferably 20 mm or less, and more preferably 16 mm or less, and, specifically, is preferably from 4 to 20 mm, and more preferably from 6 to 16 mm.

[0024]

As shown in FIGS. 4 and 5, each depressed portion 41 has a thickness that becomes smaller toward the opening 44. The state in which the thickness becomes smaller toward the opening 44 has a meaning that encompasses a state in which the thickness continuously becomes smaller toward the opening 44 and a state in which the thickness becomes smaller toward the opening 44 in a stepwise manner. As shown in FIGS. 4 and 5, an outer periphery 43 of each opening 44 in the depressed portions 41 included in the skin-side sheets 4 has a thickness that gradually becomes smaller toward an inner peripheral wall 42e (the peripheral edge of the opening 44) of the bonded portion 42 forming the opening 44. The outer periphery 43 refers to a portion from the inner peripheral wall 42e of the bonded portion 42 that is the peripheral edge (contour) of the opening 44 to the bonded portion 42 on the outer side. Preferably, each outer periphery 43 is formed in the shape of a ring starting from the inner peripheral wall 42e (the peripheral edge of the opening 44) of the bonded portion 42 in the depressed portion 41. In order to shift the wearer’s sweat toward the non-skin-side sheet 5, when the depth of each depressed portion 41 at the inner peripheral wall 42e of the bonded portion 42 is taken as d3 (see FIG. 4), the thickness at a position that is distanced outward from the inner peripheral wall 42e of the bonded portion 42 by a distance that is 0.50 times the depth (d3) is preferably from 20 to 75%, and more preferably from 30 to 65%, of a thickness d2 of portions other than the depressed portions 41, and the thickness at a position that is distanced outward from the inner peripheral wall 42e of the bonded portion 42 by a distance that is 1.5 times the depth (d3) is preferably from 55 to 95%, and more preferably from 70 to 90%, of the thickness d2 of portions other than the depressed portions 41. The depth (d3) of each depressed portion 41 at the inner peripheral wall 42e of the bonded portion 42 and the thickness at a position that is distanced therefrom are measured according to a method similar to that for a thickness d5 of the inner peripheral wall 42e of the bonded portion 42, which will be described later.

Furthermore, the thickness d2 of portions other than the depressed portions 41 included in the skin-side sheets 4 is measured using a thickness gauge in a state where 0.05 kPa of pressure is applied to the skin-side sheets 4. A laser displacement gauge manufactured by Omron Corporation is used as a thickness gauge. The thickness is measured at ten points, and an average thereof is calculated as the thickness of portions other than the depressed portions 41.

The state in which the outer periphery 43 of the opening 44 has a thickness that gradually becomes smaller toward the inner peripheral wall 42e of the bonded portion 42 can be seen from the fact that the thickness at a position that is distanced outward from the inner peripheral wall 42e of the bonded portion 42 by a distance that is 0.50 times the depth (d3) is smaller than the thickness at a position that is distanced outward from the inner peripheral wall 42e of the bonded portion 42 by a distance that is 1.5 times the depth (d3).

[0025]

In order to shift the wearer’s sweat toward the non-skin-side sheet 5, in the diaper 1, the openings 44 of the skin-side sheets 4 are each such that the inner peripheral wall 42e of the bonded portion 42 has a thickness d5 (see FIG. 4) that is preferably 60 pm or less, and more preferably 45 pm or less, and the lower limit thereof is 10 pm. The thickness d5 of the inner peripheral wall 42e of the bonded portion 42 is measured as follows. A portion including the opening 44 is cut in the thickness direction using a knife, a cutter, a razor, or the like such that the cut face of the inner peripheral wall 42e of the bonded portion 42 does not collapse, the cut cross-section is observed using a microscope, and thus the thickness of the inner peripheral wall 42e of the bonded portion 42 is measured. The thickness is measured at ten different inner peripheral walls 42e, and an average thereof is calculated as the thickness of the inner peripheral wall 42e of the bonded portion 42.

[0026]

Furthermore, in order to shift the wearer’s sweat toward the non-skin-side sheet 5, in the diaper 1, each opening 44 of the skin-side sheets 4 has a diameter LI (see FIG. 3) that is preferably 0.5 mm or greater, and more preferably 1 mm or greater, is preferably 3 mm or less, and more preferably 2.5 mm or less, and, specifically, is preferably from 0.5 to 3 mm, and more preferably from 1 to 2.5 mm. The diameter LI (see FIG. 3) of each opening 44 refers to the length of the opening 44 at the narrowest position.

[0027]

Furthermore, in the diaper 1, in order to shift the wearer’s sweat toward the nonskin-side sheet 5, each inner peripheral wall 42e of the bonded portions 42 of the skin-side sheets 4 has a thickness d5 (see FIG. 4) that is preferably 1/10 or less, and more preferably 1/30 or less, of the diameter LI (see FIG. 3) of the opening 44, and the lower limit thereof is 1/50.

[0028]

Furthermore, in the diaper 1, the openings 44 of the skin-side sheets 4 are such that the opening area of one opening 44 is preferably 0.5 mm² or greater, and more preferably 0.75 mm² or greater, in order to shift the wearer’s sweat toward the non-skinside sheet 5, and, furthermore, the opening area is preferably 5 mm² or less, and more preferably 4 mm² or less, in order to not allow sweat to return from the non-skin-side sheet 5 to the skin, and, specifically, the opening area is preferably from 0.5 to 5 mm², and more preferably from 0.75 to 4 mm².

[0029]

Furthermore, in plan view of the diaper 1 in its flat-out, uncontracted state as shown in FIG. 2, the rear waist flap FB of the diaper 1 is such that the proportion of the area of all openings 44 with respect to the total area of the skin-side sheet 4 is preferably 1% or greater, and more preferably 3% or greater, in order to efficiently shift the wearer’s sweat to the non-skin-side sheet 5, and, furthermore, the proportion is preferably 15% or less, and more preferably 10% or less, in order to not allow sweat to return from the nonskin-side sheet 5 to the skin, and, specifically, the proportion is preferably from 1 to 15%, and more preferably from 3 to 10%.

[0030]

Furthermore, in the diaper 1, in order to shift the wearer’s sweat toward the nonskin-side sheet 5, each opening 44 of the skin-side sheets 4 is preferably formed in a thin region 43T with a thickness that is 70% or less of the thickness d2 (see FIG. 4) of portions other than the depressed portion 41 in the skin-side sheets 4, inside the outer periphery 43, and more preferably formed in an opening-side thin region 43 ST with a thickness that is 40% or less of the thickness d2 (see FIG. 4), in the thin region 43 T. In the diaper 1, not only each opening 44 is formed in the thin region 43T, but also each bonded portion 42 is formed in the thin region 43T.

Furthermore, in order to not allow sweat to return from the non-skin-side sheet 5 to the skin, the thickness d2 (see FIG. 4) of portions other than the depressed portions 41 in the skin-side sheets 4 is preferably 600 pm or less, and more preferably 350 pm or less, and the lower limit thereof is 100 pm.

[0031]

In the diaper 1, each thin region 43T of the outer peripheries 43 of the openings 44 in the depressed portions 41 is formed in the shape of a ring as in the case of the outer peripheries 43. In order to shift the wearer’s sweat toward the non-skin-side sheet 5, each thin region 43T of the depressed portions 41 has a diameter L2 (see FIGS. 3(a) and 3(b)) that is preferably 1.5 times or greater, and more preferably 2 times or greater, of the diameter LI of the opening 44 (see FIGS. 3(a) and 3(b)), and the upper limit thereof is 3 times. The diameter L2 (see FIGS. 3(a) and 3(b)) of each ring-shaped thin region 43T refers to the length of the thin region 43 T at the narrowest position in the outer periphery thereof.

[0032]

The skin-side sheets 4 have a basis weight that is 30 g/m² or less, is preferably 20 g/m² or less in order to shift the wearer’s sweat toward the non-skin-side sheet 5, is preferably 9 g/m² or greater, and more preferably 10 g/m² or greater, in order to allow the skin-side sheets 4 to secure a space between the non-skin-side sheet 5 that has absorbed liquid and the skin, thereby further reliably preventing the wearer’s sweat that has been shifted to the non-skin-side sheet 5 from returning to the skin and preventing the sheet that has absorbed sweat from sticking to the skin, and, specifically, is preferably from 9 to 30 g/m², and more preferably from 10 to 20 g/m². The basis weight of the skin-side sheets 4 can be measured from the area and the weight of a sheet that can be measured. This measurement is performed at 23 ± 2°C and a relative humidity of 50 ± 5% on a sample that has been stored in the same environment for 24 hours or more before measurement.

[0033]

Furthermore, in the outer cover 3, the skin-side sheets 4 and the non-skin-side sheet 5 may be fixed to each other, for example, via the joined regions 8 through heat embossing, which will be described later, but, in the diaper 1, they are bonded to each other via an adhesive 9 as shown in FIG. 4. The adhesive 9 is applied to the non-skin-facing surface of the skin-side sheets 4 or the skin-facing surface of the non-skin-side sheet 5, for example, in the form of a spiral. In order to shift the wearer’s sweat toward the non-skinside sheet 5, the position at which the adhesive 9 is arranged preferably overlaps the bonded portions 42 of the skin-side sheets 4 when viewed in a cross-section as in FIG. 4.

[0034]

Furthermore, in the diaper 1, as shown in FIGS. 2 and 3, the outer cover 3 has a plurality of elastic members 71 arranged in a state of being stretched in the lateral direction (Y direction) between the non-skin-side sheet 5 and the outer sheet 6 and intermittently arranged along the longitudinal direction (X direction). In the diaper 1, waist elasticized portions G1 and below-waist lower elasticized portions G2 are formed by providing the plurality of elastic members 71. Furthermore, in the diaper 1, as shown in FIG. 2, a plurality of leg elastic members 72 in a stretched state are arranged between the non-skinside sheet 5 and the outer sheet 6. In the diaper 1, leg elasticized portions G3 are formed by providing the plurality of leg elastic members 72.

[0035]

As shown in FIG. 2, in the diaper 1, the waist elasticized portions G1 are formed in the end flaps that are positioned outward in the longitudinal direction X of the edges of the front and rear ends 23 A and 23B in the longitudinal direction (X direction) of the absorbent member 23 forming the absorbent assembly 2 (on the side opposite to the lateral center line CL2), in the longitudinal direction (X direction). Furthermore, in the diaper 1, the below-waist lower elasticized portions G2 are formed in the side flaps that are positioned between lower ends on the lateral center line CL2 side of the waist elasticized portions G1 and lower ends of the side seals S, in the longitudinal direction (X direction). The rear waist flap FB and the front waist flap FA described above are regions obtained by adding the end flaps (the waist elasticized portions Gl) and part of the side flaps (the belowwaist lower elasticized portions G2). Furthermore, as shown in FIG. 2, in the diaper 1, the leg elasticized portions G3 are formed along the peripheral edges of the leg openings LO.

[0036]

As shown in FIGS. 2 and 3, in the diaper 1, the outer cover 3 includes the plurality of joined regions 8 that join the non-skin-side sheet 5 and the outer sheet 6. As described above, in the diaper 1, the joined regions 8 are not formed on the skin-side sheets 4. In the diaper 1, the rear waist flap FB and the front waist flap FA are formed by joining and fixing the non-skin-side sheet 5 and the outer sheet 6 to each other via the plurality of joined regions 8 through fusion bonding arranged in a dispersed manner.

[0037]

Preferably, as shown in FIG. 2, in the diaper 1, the joined regions 8 obtained by fusion bonding the non-skin-side sheet 5 and the outer sheet 6 are intermittently arranged in a row along the longitudinal direction (X direction) in a region spanning from the waist elasticized portion G1 to the below-waist lower elasticized portion G2 of each of the front region A and the rear region B, and a plurality of joined region rows 8L formed of the plurality of joined regions 8 are arranged at intervals along the lateral direction (Y direction).

[0038]

The joined regions 8 are formed by laminating the non-skin-side sheet 5 and the outer sheet 6, and melting and solidifying the laminated portions through heat embossing. The heat embossing apparatus may be an apparatus including an embossing roller and an anvil roller, wherein the outer peripheral face of the embossing roller has a projection that conforms to the joined regions 8. As processing for forming the joined regions 8, ultrasonic sealing, a laser, and the like may be used instead of heat embossing.

[0039]

In order to improve the sweat dispersing properties, in the diaper 1, the interval between joined regions 8,8 that are adjacent to each other in the longitudinal direction (X direction) forming the joined region rows 8L extending in the longitudinal direction (X direction) is preferably 1 mm or greater, and more preferably 3 mm or greater, is preferably 20 mm or less, and more preferably 18 mm or less, and, specifically, is preferably from 1 to 20 mm, and more preferably from 3 to 18 mm.

Furthermore, in order to improve the ability to evaporate sweat that has been absorbed, the interval between joined region rows 8L,8L that are adjacent to each other in the lateral direction (Y direction) is preferably 4 mm or greater, and more preferably 6 mm or greater, is preferably 20 mm or less, and more preferably 16 mm or less, and, specifically, is preferably from 4 to 20 mm, and more preferably from 6 to 16 mm.

[0040]

The diaper 1 includes the plurality of elastic members 71 arranged in a state of being stretched in the lateral direction (Y direction) and intermittently arranged along the longitudinal direction (X direction), between the non-skin-side sheet 5 and the outer sheet 6 fixed to each other via the joined regions 8. Preferably, as shown in FIG. 2, in the diaper 1, in a region spanning from the waist elasticized portion G1 to the below-waist lower elasticized portion G2 of each of the front region A and the rear region B, the plurality of elastic members 71 are arranged in a state of being stretched in the lateral direction (Y direction) through gaps between the joined regions 8 of the plurality of joined region rows 8L. As shown in FIGS. 2 and 3, in order to not allow sweat to return from the non-skinside sheet 5 to the skin, in the diaper 1, the bonded portions 42 are preferably arranged, and the openings 44 of the skin-side sheets 4 are also preferably arranged, between the elastic members 71,71 that are adjacent to each other in the longitudinal direction (X direction).

[0041]

Furthermore, as shown in FIG. 2, in the diaper 1, a pair of outer-side fixing regions 3T1,3T1 formed by joining the non-skin-side sheet 5 and the outer sheet 6 using an elastic member fixing adhesive are arranged in both lateral side edges 3al,3al of the front region A of the outer cover 3 and both lateral side edges 3b 1,3b 1 of the rear region B of the outer cover 3, and a pair of assembly-side fixing regions 3T2,3T2 formed by joining the nonskin-side sheet 5 and the outer sheet 6 using an elastic member fixing adhesive are arranged near both sides along the longitudinal direction (X direction) of the absorbent assembly 2.

[0042]

In each of the waist elasticized portions G1 of the diaper 1, the plurality of elastic members 71 are arranged spanning between the pair of outer-side fixing regions 3T1,3T1, and the elastic members 71 are fixed between the non-skin-side sheet 5 and the outer sheet 6 in both the pair of outer-side fixing regions 3T1,3T1, but are not fixed to either the nonskin-side sheet 5 or the outer sheet 6 between the pair of outer-side fixing regions 3T1,3T1.

Furthermore, in each of the below-waist lower elasticized portions G2 of the diaper 1, the plurality of elastic members 71 are arranged spanning from the outer-side fixing region 3T1 to the assembly-side fixing region 3T2, and the elastic members 71 are fixed between the non-skin-side sheet 5 and the outer sheet 6 in all the outer-side fixing regions 3T1 and the assembly-side fixing regions 3T2, but are not fixed to either the nonskin-side sheet 5 or the outer sheet 6 between the outer-side fixing regions 3T1 and the assembly-side fixing regions 3T2. In each of the below-waist lower elasticized portions G2 of the diaper 1, the elastic members 71 are not arranged between the pair of assemblyside fixing regions 3T2,3T2, or are arranged therebetween in a state of being finely cut so as not to exert their elasticity.

[0043]

In each of the leg elasticized portions G3 of the diaper 1, the plurality of leg elastic members 72 arranged in a state of being stretched along the peripheral edges of the leg openings LO are fixed between the non-skin-side sheet 5 and the outer sheet 6 via an elastic member fixing adhesive arranged in a planar shape along the peripheral edges of the leg openings LO.

[0044]

As shown in FIGS. 1 and 6, the diaper 1 includes a gather portion G formed by the skin-side sheets 4 deforming so as to be warped inward into the diaper 1 due to contraction of the plurality of elastic members 71 arranged in a state of being stretched in the lateral direction (Y direction) between the non-skin-side sheet 5 and the outer sheet 6 and intermittently arranged along the longitudinal direction (X direction). Preferably, in the outer cover 3 of the diaper 1, the gather portion G is formed by the outer sheet 6 between the joined region rows 8L,8L that are adjacent to each other in the lateral direction (Y direction) deforming so as to be warped outward and the skin-side sheets 4 and the nonskin-side sheet 5 fixed to each other via the adhesive 9 deforming so as to be warped inward, due to contraction of the plurality of elastic members 71 arranged in a state of being stretched in the lateral direction (Y direction) between the non-skin-side sheet 5 and the outer sheet 6 and intermittently arranged along the longitudinal direction (X direction), in the waist elasticized portions G1 and the below-waist lower elasticized portions G2. Creases 3F formed of the outer sheet 6 or the skin-side sheets 4 and the non-skin-side sheet are generated between the joined region rows 8L,8L that are adjacent to each other, and hollow portions 3H surrounded by the creases 3F and creases 3F are formed between the outer sheet 6, and the skin-side sheets 4 and the non-skin-side sheet 5.

[0045]

In order to shift the wearer’s sweat toward the non-skin-side sheet 5, when viewed in a cross-section of the gather portion G formed through contraction of the elastic members 71 as in FIG. 6, preferably 60% or greater of all of the bonded portions 42, and more preferably 75% or greater of all of the bonded portions 42 are arranged from a position that is at half a depth d4 of depressions depressed toward the non-skin side of the skin-side sheets 4 to the projection side (the skin-facing surface side), and the upper limit thereof is preferably 100%.

[0046]

Hereinafter, materials for forming the constituent elements of the diaper 1 will be described.

The skin-side sheets 4 are sheets formed of a hydrophobic nonwoven fabric or the like made of a hydrophobic fiber, and the non-skin-side sheet 5 is a sheet formed of a hydrophilic nonwoven fabric or the like made of a hydrophilic fiber.

In the diaper 1, the skin-side sheets 4 forming the outer cover 3 are formed of the folded-back portions 6R of the outer sheet 6, and thus the entire outer sheet 6 including the folded-back portions 6R (the skin-side sheets 4) is formed of a hydrophobic sheet made of a hydrophobic fiber, and the non-skin-side sheet 5 that is separate from the outer sheet 6 is formed of a hydrophilic sheet.

[0047]

The hydrophobic fiber forming the hydrophobic sheet used for the outer sheet 6 (including the skin-side sheets 4) may be a synthetic fiber, and specifically may be those ordinarily used as constituent fibers of various nonwoven fabrics, and examples thereof include: polyolefin fibers such as a polyethylene (PE) fiber and a polypropylene (PP) fiber; fibers using a thermoplastic resin such as polyethylene terephthalate (PET) or polyamide alone; and composite fibers such as core-sheath type and side-by-side type composite fibers.

[0048]

The hydrophilic fiber forming the hydrophilic sheet used for the non-skin-side sheet 5 may be a fiber obtained by hydrophilizing a synthetic fiber, and specifically may be a fiber obtained by treating a hydrophobic synthetic fiber with a hydrophilizing agent, or a fiber obtained by kneading a hydrophilizing agent into a fiber. Furthermore, a composite nonwoven fabric obtained by mixing a naturally hydrophilic fiber such as a natural or seminatural fiber with a synthetic fiber also may be used. There is no particular limitation on the synthetic fiber, and examples thereof include: polyolefin fibers such as a polyethylene (PE) fiber and a polypropylene (PP) fiber; fibers using a thermoplastic resin such as polyethylene terephthalate (PET) or polyamide alone; and composite fibers such as coresheath type and side-by-side type composite fibers. There is no particular limitation on the hydrophilizing agent used to hydrophilize a synthetic fiber, as long as it is an ordinary hydrophilizing agent used for hygiene products. Specific examples of the hydrophilic fiber include: natural cellulose fibers such as wood pulps and non-wood pulps such as a cotton pulp and a straw pulp; and regenerated cellulose fibers such as rayon and cupro. Furthermore, examples of the hydrophilic sheet may include hydrophilic clothing in addition to hydrophilic nonwoven fabrics. Examples of the types of hydrophilic nonwoven fabrics include air-through nonwoven fabric, spunbonded nonwoven fabric, heat-rolled nonwoven fabric, spunlaced nonwoven fabric, and meltblown nonwoven fabric.

[0049]

Whether the fiber forming the sheet is hydrophilic or hydrophobic may be determined based on a contact angle of a constituent fiber measured using “Method for Measuring Fiber Contact Angle”, which will be described below. Specifically, if the contact angle is 90° or greater, it is determined that the fiber is a hydrophobic fiber with low hydrophilicity, and, if the contact angle is less than 90°, it is determined that the fiber is a hydrophilic fiber with high hydrophilicity.

Method for Measuring Fiber Contact Angle

A contact angle is measured, for example, using a contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. Specifically, immediately after ion exchange water (about 20 picoliters) is dropped onto a surface of a fiber forming the outer peripheries 43, the contact angle is measured using the contact angle meter. The measurement is performed at five or more points on fiber forming a portion near the inner peripheral walls 42e of the bonded portions 42 or fiber forming a portion near the outer edges of the depressed portions 41, and an average thereof is calculated as the contact angle. Note that the measurement environment temperature is set to 20°C.

[0050]

As the topsheet 21, the backsheet 22, the absorbent member 23, the leak-proof cuffs 24, and the like forming the absorbent assembly 2, various types of members conventionally used for absorbent articles such as disposable diapers can be used without any specific limitation. For example, the topsheet 21 may be a monolayered or multilayered nonwoven fabric, an apertured film, or the like. The backsheet 22 may be a moisture permeable resin film or the like. The absorbent member 23 may be an absorbent core made of absorbent polymer particles and fiber materials wrapped in tissue paper. Furthermore, the leak-proof cuffs 24 may be a water repellent monolayered or multilayered nonwoven fabric, or the like.

[0051]

Examples of the material for forming the elastic members (the leak-proof cuff forming elastic members 25, the elastic members 71, the leg elastic members 72, etc.) include a synthetic rubber, such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, elastic polyolefin, and polyurethane. With respect to the form of the elastic members, filamentous elastic members (rubber thread, etc.) or string-like elastic members (flat rubber string, etc.) having a rectangular, square, circular, elliptical, or polygonal cross-sectional shape or the like can be preferably used.

[0052]

As the elastic member fixing adhesive for fixing the adhesive 9, the elastic members (the leak-proof cuff forming elastic members 25, the elastic members 71, the leg elastic members 72, etc.), and the assembly fixing adhesive for fixing the outer cover 3, the absorbent assembly 2, and the like, various types of hot melt adhesives and the like conventionally used for absorbent articles such as disposable diapers can be used without any specific limitation.

[0053]

Hereinafter, actions and effects obtained when using the diaper 1 of the foregoing embodiment of the present invention will be described.

As shown in FIGS. 2 to 5, in the diaper 1, at least the rear waist flap FB has a hydrophobic skin-side sheet 4 and the hydrophilic non-skin-side sheet 5, the hydrophobic skin-side sheet 4 includes the depressed portions 41 depressed toward the non-skin-side sheet 5 and the openings 44 in the respective depressed portions 41. The thickness of each depressed portion 41 of the skin-side sheets 4 becomes smaller toward the opening 44. That is to say, the inter-fiber distance between constituent fibers gradually becomes smaller toward the openings 44. Accordingly, when the diaper 1 is worn, the wearer’s sweat is likely to be drawn from portions other than the depressed portions 41 toward the depressed portions 41, and the thickness of the depressed portions 41 becomes smaller toward the opening 44, and thus sweat is likely to quickly shift from the openings 44 to the hydrophilic non-skinside sheet 5. The thus shifted wearer’s sweat inside the hydrophilic non-skin-side sheet 5 is not likely to return to the hydrophobic skin-side sheets 4 or the skin. In this manner, the wearer’s sweat that has been shifted to the non-skin-side sheet 5 on the non-skin-facing surface side is not likely to come into contact with the skin, and thus skin issues such as eczema, heat rashes, and rashes can be reduced.

[0054]

Furthermore, as shown in FIGS. 2 and 4, in the diaper 1, the bonded portions 42 in which constituent fibers of the skin-side sheets 4 are bonded to each other are arranged in the respective depressed portions 41. Furthermore, the bonded portions 42 include portions in which constituent fibers of the skin-side sheets 4 are melted and bonded to each other with no gap therebetween. In the diaper 1, the openings 44 are formed inside the bonded portions 42. The fiber density of the bonded portions 42 is higher than the fiber density of the outer peripheries 43 of the openings 44 at the depressed portions 41, and the fiber density of the outer peripheries 43 is higher than the fiber density of portions other than the depressed portions 41. The portions that are bonded with no gap therebetween are liquid impermeable portions that do not allow liquids to pass therethrough, but are portions with relatively high hydrophilicity, and thus, when the diaper 1 is worn, the wearer’s sweat is more likely to be drawn from portions other than the depressed portions 41 toward the depressed portions 41, and sweat is more likely to quickly shift from the outer peripheries 43 with high fiber density via the openings 44 of the bonded portions 42 to the hydrophilic non-skin-side sheet 5. In this manner, the wearer’s sweat is more likely to shift to the non-skin-side sheet 5 on the non-skin-facing surface side, and thus skin issues such as eczema, heat rashes, and rashes can be further reduced. Furthermore, in the diaper 1, the portions that are bonded with no gap therebetween are in the form of a film, and thus the above-described effects are more reliably achieved. Furthermore, if the basis weight of the skin-side sheets 4 is 30 g/m² or less, the above-described effects are more reliably achieved.

[0055]

Furthermore, as shown in FIG. 2, in the diaper 1, the hydrophobic outer sheet 6 is arranged on the non-skin-facing surface side of the non-skin-side sheet 5, and the plurality of elastic members 71 are arranged in a state of being stretched in the lateral direction (Y direction) through gaps between the joined regions 8 of the plurality of joined region rows 8L, in regions spanning respectively from the waist elasticized portions G1 to the belowwaist lower elasticized portions G2. As shown in FIG. 6, when the elastic members 71 arranged in a state of being stretched are contracted, the creases 3F formed of the skin-side sheets 4 and the non-skin-side sheet 5, and the outer sheet 6 are generated between the joined region rows 8F,8F that are adjacent to each other, and the hollow portions 3H surrounded by the creases 3F and the creases 3F are formed between the skin-side sheets 4 and the non-skin-side sheet 5, and the outer sheet 6. Accordingly, the ability to evaporate the wearer’s sweat that has been shifted to the non-skin-side sheet 5 is improved, and skin issues such as eczema, heat rashes, and rashes can be further reduced.

[0056]

In order to facilitate the reliable shift of wearer’s sweat to the non-skin-side sheet 5, the inter-fiber distance between constituent fibers forming the skin-side sheets 4 at the depressed portions 41 is preferably smaller on the openings 44 side than on the outer side of the openings 44. More specifically, the inter-fiber distance between fibers forming the opening-side thin regions 43 ST at the outer peripheries 43 is preferably 4/5 or less, and more preferably 2/5 or less of the inter-fiber distance between fibers forming portions near the outer edges of the depressed portions 41 at the outer peripheries 43.

The inter-fiber distance between fibers forming the opening-side thin regions 43 ST at the outer peripheries 43 and the inter-fiber distance between fibers forming portions near the outer edges of the depressed portions 41 are measured using the following method. A smaller value of the inter-fiber distance measured using the following method indicates higher hydrophilicity.

[0057]

Method for Measuring Inter-Fiber Distance

At each measurement portion, the basis weight, the thickness, and the fiber denier are measured, and the inter-fiber distance is calculated according to Formula 1. When different portions of the same sheet are measured, the basis weight and the fiber denier of the sheet do not change, and only the thickness thereof changes. The thickness is measured as follows. The thickness of the sheet is measured by cutting the sheet including a measurement portion in the thickness direction using a knife, a cutter, a razor, or the like such that the cut face does not collapse, and observing the cut cross-section using a microscope, thereby measuring the thickness of the measurement portion. The thickness is measured at ten different points, and an average thereof is calculated as the thickness of the measurement portion.

[0058]

In order to facilitate the above-described effects, the contact angle between the skin-side sheets 4 at the depressed portions 41 and ion exchange water is preferably smaller on the openings 44 side than on the outer side of the openings 44. In other words, the hydrophilicity of the skin-side sheets 4 at the depressed portions 41 is preferably larger on the openings 44 side than on the outer side of the openings 44. More specifically, the skinside sheets forming the openings 44 side (the opening-side thin regions 43 ST) at the outer peripheries 43 have a contact angle with respect to ion exchange water that is preferably 120° or less, and more preferably 110° or less. There is no particular limitation on the lower limit of the contact angle of the thus configured skin-side sheets, but the lower limit is 90° because the skin-side sheets are hydrophobic.

Furthermore, the skin-side sheets forming the outer side of each opening 44 (near the outer edges of the depressed portions 41 at the outer peripheries 43) have a contact angle with respect to ion exchange water that is preferably 120° or greater, and more preferably 130° or greater. If the upper limit of the contact angle of the thus configured skin-side sheets is 180°, sufficiently satisfactory results are obtained.

Furthermore, a difference between the contact angle between the skin-side sheets on the opening 44 side (the opening-side thin regions 43 ST) and ion exchange water and the contact angle between the outer side of the opening 44 (near the outer edges of the depressed portions 41 at the outer peripheries 43) and ion exchange water is preferably large. More specifically, the difference between the contact angles is preferably 10° or greater, and more preferably 20° or greater.

The contact angle between the skin-side sheets forming the opening-side thin regions 43 ST at the outer peripheries 43 or the skin-side sheets forming portions near the outer edges of the depressed portions 41 at the outer peripheries 43 and ion exchange water is measured using the following method. A smaller value of the contact angle measured using the following method indicates higher hydrophilicity.

[0059]

Method for Measuring Contact Angle of Sheet

Measurement was performed using a medium-magnification zoom lens inclined at 90° with respect to a microscope VHX-1000 manufactured by Keyence Corporation. The sheet cut into a portion with a size of MD direction 150 mm x CD direction 70 mm was used as a measurement sample. The measurement environment was set to 20°C/50%RH, and the measurement sample was set on a measurement stage with the measurement face being oriented upward such that the sheet could be observed from the CD direction thereof. Then, 3 pL of ion exchange water was applied to measurement portions (the opening-side thin regions 43 ST at the outer peripheries 43 and portions near the outer edges of the depressed portions 41 at the outer peripheries 43) of the measurement sample set on the measurement stage, and an image thereof was captured. The contact angle was measured at ten points where observation results of both or one end of a water drop on the sheet were clearly in focus, and an average thereof was calculated as “contact angle”.

[0060]

In order to absorb a large amount of sweat and reduce the amount of sweat that comes into contact with skin, and not to allow sweat to return from the non-skin-side sheet to the skin, the non-skin-side sheet 5 has a basis weight that is preferably 10 g/m² or greater, and more preferably 20 g/m² or greater, is preferably 50 g/m² or less, and more preferably 30 g/m² or less, and, specifically, is preferably from 10 to 50 g/m², and more preferably from 20 to 30 g/m².

From the same point of view, the non-skin-side sheet 5 is such that portions thereof other than the depressed portions 41 have a thickness that is preferably 100 pm or greater, and more preferably 150 pm or greater, is preferably 800 pm or less, and more preferably 500 pm or less, and, specifically, is preferably from 100 to 800 pm, and more preferably from 150 to 500 pm. The thickness of the non-skin-side sheet 5 is measured using a thickness gauge in a state where 0.05 kPa of pressure is applied to the non-skin-side sheet 5. A laser displacement gauge manufactured by Omron Corporation is used as a thickness gauge. The thickness is measured at ten points, and an average thereof is calculated as the thickness.

[0061]

In order to facilitate the reliable shift of wearer’s sweat to the non-skin-side sheet 5, the non-skin-side sheet 5 has a hydrophilic fiber content with respect to all constituent fibers of preferably 80% by mass or greater, and more preferably 90% by mass or greater, and the lower limit thereof is preferably 70% by mass.

[0062]

Furthermore, in order to facilitate the reliable shift of wearer’s sweat to the nonskin-side sheet 5, the non-skin-side sheet 5 has a Klemm water absorption height at 30 mm width, as measured according to JIS P 8141, of preferably 20 mm or greater at 60 seconds, and more preferably 25 mm or greater at 60 seconds. There is no particular limitation on the upper limit of the Klemm water absorption height of the non-skin-side sheet 5, but sufficiently satisfactory results are obtained if it is 30 mm at 60 seconds.

The Klemm water absorption height of the non-skin-side sheet 5 is measured using the following method.

[0063]

Method for Measuring Klemm Water Absorption Height

When taking the non-skin-side sheet 5 out of the outer cover of the pull-on disposable diaper, if the skin-side sheets 4, the non-skin-side sheet 5, and the outer sheet 6 are fusion bonded or fixed via an adhesive to each other, the fixed portions are eliminated through melting or the like using a solvent or hot air from a drier or the like, and thus the non-skin-side sheet 5 is taken out. The taken out non-skin-side sheet 5 is taken as a sample and the Klemm water absorption height thereof is measured according to the test method as defined in JIS P 8141. Specifically, the taken out non-skin-side sheet 5 is cut into a portion with a width (the length in the longitudinal direction (X direction) of the diaper 1) of 30 mm and a length (the length in the lateral direction (Y direction) of the diaper 1) of 150 mm. When performing the cutting, cutting methods with which a sample may collapse due to pressure, such as those using a pushing cutter, are not preferable because the results may be severely affected. Thus, when performing the cutting, the sample is cut using a knife, a cutter, a razor, or the like such that the cut face thereof does not collapse. Next, the cut sample is set on a jig as defined in JIS P 8141, the Klemm water absorption height after 60 seconds is measured using water as a test liquid. The test liquid may be colored as appropriate using a dye such as Blue No.l or methylene blue such that the absorption height can be easily seen. This measurement is performed five times, and an average thereof is calculated as the Klemm water absorption height of the non-skin-side sheet 5. Note that the measurement environment temperature is set to 22°C.

[0064]

Furthermore, in order to facilitate the reliable shift of wearer’s sweat to the nonskin-side sheet 5, the non-skin-side sheet 5 has a saturated water-absorption amount of ion exchange water of preferably 75 g/m² or greater, and more preferably 100 g/m² or greater. There is no particular limitation on the upper limit of the saturated water-absorption amount of the non-skin-side sheet 5, but sufficiently satisfactory results are obtained if it is 300 g/m².

The saturated water-absorption amount of the non-skin-side sheet 5 is measured using the following method.

[0065]

Method for Measuring Saturated Water-Ab sorption Amount

A measurement sample is produced by cutting the non-skin-side sheet into a portion with a width of 50 mm and a length of 50 mm. The measurement sample is immersed in ion exchange water whose temperature is adjusted to 25°C. The sample is taken out of the ion exchange water five minutes after the immersion is started, and is then drained by being vertically suspended for 30 seconds. The mass of the sample that has absorbed water is measured, and the targeted saturated water-absorption amount is calculated using the following formula. The calculation is performed as follows: Saturated water-absorption amount (g/m²) = (sample mass (g) after water absorption sample mass (g) before water absorption) / (measurement sample area 0.05 m x 0.05 m). This measurement is performed five times, and an average thereof is calculated as the saturated water-absorption amount of the non-skin-side sheet.

[0066]

Although the present invention has been described above, the present invention is not limited to the foregoing embodiment, and changes can be made thereto as appropriate.

For example, the above-described diaper 1 is such that the skin-side sheets 4 forming the outer cover 3 are formed of the folded-back portions 6R of one outer sheet 6 as shown in FIG. 2, but may be hydrophobic sheets (nonwoven fabrics) that are separate from the outer sheet 6. If such skin-side sheets 4 are arranged as separate members, it is sufficient that at least the rear waist flap FB of the front waist flap FA and the rear waist flap FB is provided with such a skin-side sheet 4 as a separate member.

[0067]

Furthermore, as shown in FIG. 4, in the diaper 1, the number of hydrophilic nonskin-side sheets 5 provided at least in the rear waist flap FB is one, but may be two or more. If the number of hydrophilic non-skin-side sheets 5 is two or more in this manner, their hydrophilicity preferably increases in accordance with an increase in the distance from the wearer’s skin. That is to say, in comparison with a non-skin-side sheet that is adjacent to the skin-side sheet 4, at least any one of the above-described hydrophilic fiber content with respect to all constituent fibers, the above-described basis weight of the non-skin-side sheet, the above-described Klemm water absorption height, and the above-described saturated water-absorption amount is preferably larger than that of the non-skin-side sheet that is adjacent to the skin-side sheet 4, in accordance with an increase in the distance from the skin-side sheet 4. Furthermore, in comparison with a non-skin-side sheet that is adjacent to the skin-side sheet 4, at least any one of the inter-fiber distance between fibers forming the non-skin-side sheet and the contact angle between the fibers forming the non-skin-side sheet and ion exchange water is preferably smaller than that of the non-skin-side sheet that is adjacent to the skin-side sheet 4, in accordance with an increase in the distance from the skin-side sheet 4. The contact angle between the fibers forming the non-skin-side sheet and ion exchange water is measured using the above-described method. Furthermore, the inter-fiber distance between fibers forming the non-skin-side sheet is measured using the following method.

t

P oii Σ — i-1 Di [0068]

Method for Measuring Inter-Fiber Distance

The inter-fiber distance can be obtained using Formula 1 below.

Inter-fiber distance (pm) -1(/ —

9w v where L is the thickness (cm) of a sheet (the outer sheet 4, the skin-side sheet 5, or the inner sheet 6), w is the basis weight (g/m²) of the sheet, Di is the fiber denier of a constituent fiber i forming the sheet, and oci is the weight proportion (%) of the constituent fiber i.

[0069]

Furthermore, as shown in FIG. 2, in the outer cover 3 of the diaper 1, the outer sheet 6 and the non-skin-side sheet 5 joined and fixed to each other via the plurality of joined regions 8 through fusion bonding, and the skin-side sheets 4 and the non-skin-side sheet 5 are fixed to each other via the adhesive 9, but the adhesive 9 may not be provided. Furthermore, as shown in FIG. 2, in the outer cover 3 of the diaper 1, the elastic members 71 are arranged between the outer sheet 6 and the non-skin-side sheet 5, but the elastic members 71 may not be provided therebetween.

[0070]

Furthermore, as shown in FIG. 2, the above-described disposable diaper 1 is a pullon disposable diaper in which the outer cover 3 is in the shape of an hourglass or the like continuously extending from the front region A via the crotch region C to the rear region B, but may be a pull-on disposable diaper in which the outer cover 3 is of a separate type and is divided into separate members composed of a front outer cover, a rear outer cover, and a crotch outer cover.

[0071]

Furthermore, as shown in FIG. 1, the above-described disposable diaper 1 is a pullon disposable diaper having the outer cover 3, but may be an open type disposable diaper. In the case of an open type disposable diaper including a liquid permeable topsheet, a sparingly liquid permeable backsheet, and an absorbent member between these sheets, the topsheet corresponds to the non-skin-side sheet 5. It is sufficient that at least the rear waist flap FB of the front waist flap FA and the rear waist flap FB extending in the lateral direction Y and positioned outward of the front and rear ends, respectively, in the longitudinal direction X of the absorbent member is provided with a hydrophobic skin-side sheet 4 as a separate member that forms the skin-contacting surface.

[0072]

With regard to the foregoing embodiments, the following disposable diapers will be further disclosed.

[0073] < 1 > A disposable diaper comprising, in a longitudinal direction, a front region, a rear region, and a crotch region positioned between the front region and the rear region, having an absorbent member spanning from the front region to the rear region, and having a front waist flap and a rear waist flap extending in a lateral direction and positioned outward of front and rear end portions, respectively, in the longitudinal direction of the absorbent member,wherein at least the rear waist flap has a hydrophobic skin-side sheet that forms a skin-contacting surface, and a hydrophilic non-skin-side sheet that is positioned on a nonskin-facing surface side of the skin-side sheet,the skin-side sheet includes a plurality of depressed portions depressed toward the non-skin-side sheet, and openings formed through the skin-side sheet respectively in the depressed portions, and each depressed portion of the skin-side sheet has a thickness that becomes smaller toward the opening.

<2> The disposable diaper as set forth in clause < 1 >, wherein each opening of the skin-side sheet has a diameter that is from 0.5 to 3 mm.

<3> The disposable diaper as set forth in clause < 1 > or < 2 >, wherein a peripheral edge of each opening of the skin-side sheet has a thickness that is 1/10 or less of a diameter of the opening.

<4> The disposable diaper as set forth in any one of clauses <1> to < 3 >, wherein each opening of the skin-side sheet is formed in a thin region of the depressed portion with a thickness that is 70% or less of a thickness of portions other than the depressed portion in the skin-side sheet.

[0074] < 5 > The disposable diaper as set forth in clause < 4 >, wherein the thin region of each depressed portion is in the shape of a ring, and has a diameter that is 1.5 times or greater of a diameter of the opening.

< 6 > The disposable diaper as set forth in any one of clauses < 1 > to < 5 >, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portion includes a portion in which constituent fibers of the skin-side sheet are melted and bonded to each other with no gap therebetween, and the opening is formed inside the bonded portion.

<7> The disposable diaper as set forth in any one of clauses <1> to < 6>, wherein the skin-side sheet at the depressed portion has a hydrophilicity that is larger on the opening side than on the outer side of the opening.

< 8 > The disposable diaper as set forth in any one of clauses < 1 > to < 7 >, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the non-skin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and each opening of the skin-side sheet is arranged between the elastic members that are adjacent to each other in the longitudinal direction.

< 9 > The disposable diaper as set forth in any one of clauses < 1 > to < 8 >, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the skin-side sheet and the non-skin-side sheet are bonded to each other via an adhesive, and the portion in which the adhesive is arranged overlaps the bonded portion of the skin-side sheet.

[0075] <10> The disposable diaper as set forth in any one of clauses <1> to < 9>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and the bonded portion is such that the portion that is bonded is in the form of a film.

<11> The disposable diaper as set forth in any one of clauses <1> to <10>, wherein the disposable diaper has a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and the skin-side sheet is formed of a folded-back portion of the outer sheet.

<12> The disposable diaper as set forth in any one of clauses <1> to < 11 >, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and the openings (the bonded portions in which the openings are arranged) are intermittently arranged throughout the skin-side sheet.

<13> The disposable diaper as set forth in any one of clauses <1> to <12>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portions respectively have the openings and are intermittently arranged in a row along the longitudinal direction, and a plurality of bonded portion rows formed of the plurality of bonded portions are arranged at intervals along the lateral direction.

< 14 > The disposable diaper as set forth in clause < 13 >, wherein an interval between the bonded portions that are adjacent to each other in the longitudinal direction and that form the bonded portion rows extending in the longitudinal direction is preferably 1 mm or greater, and more preferably 3 mm or greater, is preferably 20 mm or less, and more preferably 18 mm or less.

[0076] <15> The disposable diaper as set forth in clause <13> or <14>, wherein an interval between the bonded portion rows that are adjacent to each other in the lateral direction is preferably 4 mm or greater, and more preferably 6 mm or greater, is preferably 20 mm or less, and more preferably 16 mm or less.

<16> The disposable diaper as set forth in any one of clauses <1> to <15>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and, when a depth of the depressed portion at an inner peripheral wall of the bonded portion is taken as d3, a thickness at a position that is distanced outward from the inner peripheral wall of the bonded portion by a distance that is 0.50 times the depth d3 is preferably from 20 to 75%, and more preferably from 30 to 65%, of a thickness d2 of portions other than the depressed portion. <17> The disposable diaper as set forth in any one of clauses <1> to <16>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and a thickness at a position that is distanced outward from an inner peripheral wall of the bonded portion by a distance that is 1.5 times the depth d3 is preferably from 55 to 95%, and more preferably from 70 to 90%, of a thickness d2 of portions other than the depressed portion.

<18> The disposable diaper as set forth in any one of clauses <1> to <17>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portion of the skin-side sheet is such that an inner peripheral wall of the bonded portion has a thickness d5 that is preferably 60 pm or less, and more preferably 45 pm or less, and a lower limit thereof is 10 pm.

<19> The disposable diaper as set forth in any one of clauses <1> to <18>, wherein each opening of the skin-side sheet has a diameter LI that is preferably 0.5 mm or greater, and more preferably 1 mm or greater, is preferably 3 mm or less, and more preferably 2.5 mm or less, and, specifically, is preferably from 0.5 to 3 mm, and more preferably from 1 to 2.5 mm..

[0077] <20> The disposable diaper as set forth in any one of clauses <1> to <19>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and an inner peripheral wall of the bonded portion has a thickness d5 that is preferably 1/10 or less, and more preferably 1/30 or less, of a diameter LI of the opening, and a lower limit thereof is 1/50 thereof.

<21 > The disposable diaper as set forth in any one of clauses <1> to <20>, wherein the openings of the skin-side sheet are such that an opening area of one opening is is preferably 0.5 mm² or greater, and more preferably 0.75 mm² or greater, is preferably 5 mm² or less, and more preferably 4 mm² or less.

<22 > The disposable diaper as set forth in any one of clauses <1> to <21>, wherein a proportion of an area of all openings with respect to a total area of the skin-side sheet is preferably 1% or greater, and more preferably 3% or greater, is preferably 15% or less, and more preferably 10% or less.

<23> The disposable diaper as set forth in any one of clauses <1> to <22>, wherein each opening of the skin-side sheet is preferably formed in a thin region of the depressed portion with a thickness that is 70% or less of a thickness d2 of portions other than the depressed portion in the skin-side sheet, inside an outer periphery of the depressed portion, and more preferably formed in an opening-side thin region with a thickness that is 40% or less of the thickness d2, in the thin region.

<24> The disposable diaper as set forth in any one of clauses <1> to <23>, wherein a thickness d2 of portions other than the depressed portion in the skin-side sheet is preferably 600 pm or less, and more preferably 350 pm or less,, and a lower limit thereof is 100 pm.

[0078] <25> The disposable diaper as set forth in any one of clauses <1> to <24>, wherein a thin region of an outer periphery of each opening in the depressed portions is formed in the shape of a ring as in the case of the outer periphery.

<26> The disposable diaper as set forth in any one of clauses <1> to <25>, wherein a thin region of each depressed portion has a diameter L2 that is preferably 1.5 times or greater, and more preferably 2 times or greater, of a diameter LI of the opening, and an upper limit thereof is 3 times thereof.

<27> The disposable diaper as set forth in any one of clauses <1> to <26>, wherein the skin-side sheet has a basis weight that is 30 g/m² or less, is preferably 20 g/m²or less, is preferably 9 g/m² or greater, and more preferably 10 g/m² or greater.

<28> The disposable diaper as set forth in any one of clauses <1> to <27>, wherein the rear waist flap and the front waist flap are formed by joining and fixing the non-skin-side sheet 5 and an outer sheet 6 to each other via a plurality of joined regions 8 arranged in a dispersed manner.

<29> The disposable diaper as set forth in any one of clauses <1> to <28>, wherein a hydrophobic outer sheet is provided on the non-skin-facing surface side of the non-skin-side sheet, joined regions of the non-skin-side sheet and the outer sheet are intermittently arranged in a row along the longitudinal direction in a region spanning from a waist elasticized portion to a below-waist lower elasticized portion of each of the front region and the rear region, and a plurality of joined region rows formed of the plurality of joined regions are arranged at intervals along the lateral direction.

[0079] <30> The disposable diaper as set forth in clause <29>, wherein an interval between the joined regions that are adjacent to each other in the longitudinal direction and form the joined region rows extending in the longitudinal direction is preferably 1 mm or greater, and more preferably 3 mm or greater, is preferably 20 mm or less, and more preferably 18 mm or less.

<31> The disposable diaper as set forth in clause <29> or <30>, wherein an interval between the joined region rows that are adjacent to each other in the lateral direction is preferably 4 mm or greater, and more preferably 6 mm or greater, is preferably 20 mm or less, and more preferably 16 mm or less.

<32> The disposable diaper as set forth in any one of clauses <1> to <31 >, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the nonskin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and the skin-side sheet has a bonded portion in each of the depressed portions, and the bonded portions are preferably arranged, and the openings of the skin-side sheet are also preferably arranged between the elastic members that are adjacent to each other in the longitudinal direction.

<33> The disposable diaper as set forth in any one of clauses <1> to <32>, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the nonskin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and the skin-side sheet has a bonded portion in each of the depressed portions, and when viewed in a cross-section of a gather portion formed through contraction of the elastic members, preferably 60% or greater of all of the bonded portions, and more preferably 75% or greater of all of the bonded portions are arranged from a position that is at half a depth d4 of depressions depressed toward the non-skin side of the skin-side sheet to the projection side (the skin-facing surface side), and the upper limit thereof is preferably 100%.

<34> The disposable diaper as set forth in any one of clauses <1> to <33>, wherein an inter-fiber distance between constituent fibers forming the skin-side sheet in each depressed portion is preferably smaller on the opening side than on the outer side of the opening.

[0080] <35> The disposable diaper as set forth in any one of clauses <1> to <34>, wherein an inter-fiber distance between fibers forming an opening-side thin region with a thickness that is 40% or less of a thickness d2 of portions other than the depressed portion, in an outer periphery of the opening, inside a thin region with a thickness that is 70% or less of the thickness d2, is preferably 4/5 or less, and more preferably 2/5 or less of an interfiber distance between fibers forming a portion near an outer edge of the depressed portion at the outer periphery.

<36> The disposable diaper as set forth in any one of clauses <1> to <35>, wherein the skin-side sheet forming an opening-side thin region with a thickness that is 40% or less of a thickness d2 of portions other than the depressed portion, in an outer periphery of the opening, inside a thin region with a thickness that is 70% or less of the thickness d2, has a contact angle with respect to ion exchange water that is preferably 120° or less, and more preferably 110° or less.

<37> The disposable diaper as set forth in any one of clauses <1> to <36>, wherein the skin-side sheet forming a portion near an outer edge of the depressed portion in an outer periphery of the opening has a contact angle with respect to ion exchange water that is preferably 120° or greater, and more preferably 130° or greater.

<38> The disposable diaper as set forth in any one of clauses <1> to <37>, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and a difference between a contact angle between a portion near the bonded portion and ion exchange water and a contact angle between a portion near an outer edge of the depressed portion in an outer periphery of the opening and ion exchange water is preferably large, and the difference between the contact angles is preferably 10° or greater, and more preferably 20° or greater. <39> The disposable diaper as set forth in any one of clauses <1> to <38>, wherein the non-skin-side sheet has a basis weight that is preferably 10 g/m² or greater, and more preferably 20 g/m² or greater, is preferably 50 g/m² or less, and more preferably 30 g/m² or less.

[0081] <40> The disposable diaper as set forth in any one of clauses <1> to <39>, wherein the non-skin-side sheet is such that portions thereof other than the depressed portions have a thickness that is preferably 100 pm or greater, and more preferably 150 pm or greater, is preferably 800 pm or less, and more preferably 500 pm or less.

<41 > The disposable diaper as set forth in any one of clauses <1> to <40>, wherein the non-skin-side sheet has a hydrophilic fiber content with respect to all constituent fibers of preferably 80% by mass or greater, and more preferably 90% by mass or greater, and the lower limit thereof is preferably 70% by mass.

<42> The disposable diaper as set forth in any one of clauses <1> to <41>, wherein the non-skin-side sheet has a Klemm water absorption height at 30 mm width, as measured according to JIS P 8141, of preferably 20 mm or greater at 60 seconds, and more preferably 25 mm or greater at 60 seconds.

<43> The disposable diaper as set forth in any one of clauses <1> to <42>, wherein the non-skin-side sheet has a saturated water-absorption amount of ion exchange water of preferably 75 g/m² or greater, and more preferably 100 g/m² or greater.

Industrial Applicability [0082]

According to the present invention, sweat that has been absorbed can be quickly shifted to the non-skin-facing surface side, skin issues such as eczema, heat rashes, and rashes can be reduced.

Claims

CLAIMS [Claim 1] A disposable diaper comprising, in a longitudinal direction, a front region, a rear region, and a crotch region positioned between the front region and the rear region, having an absorbent member spanning from the front region to the rear region, and having a front waist flap and a rear waist flap extending in a lateral direction and positioned outward of front and rear end portions, respectively, in the longitudinal direction of the absorbent member, wherein at least the rear waist flap has a hydrophobic skin-side sheet that forms a skin-contacting surface, and a hydrophilic non-skin-side sheet that is positioned on a nonskin-facing surface side of the skin-side sheet, the skin-side sheet includes a plurality of depressed portions depressed toward the non-skin-side sheet, and openings formed through the skin-side sheet respectively in the depressed portions, and each depressed portion of the skin-side sheet has a thickness that becomes smaller toward the opening.
[Claim 2] The disposable diaper according to claim 1, wherein each opening of the skin-side sheet has a diameter that is from 0.5 to 3 mm.
[Claim 3] The disposable diaper according to claim 1 or 2, wherein a peripheral edge of each opening of the skin-side sheet has a thickness that is 1/10 or less of a diameter of the opening.
[Claim 4] The disposable diaper according to any one of claims 1 to 3, wherein each opening of the skin-side sheet is formed in a thin region of the depressed portion with a thickness that is 70% or less of a thickness of portions other than the depressed portion in the skin-side sheet.
[Claim 5] The disposable diaper according to claim 4, wherein the thin region of each depressed portion is in the shape of a ring, and has a diameter that is 1.5 times or greater of a diameter of the opening.
[Claim 6] The disposable diaper according to any one of claims 1 to 5, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portion includes a portion in which constituent fibers of the skin-side sheet are melted and bonded to each other with no gap therebetween, and the opening is formed inside the bonded portion.
[Claim 7] The disposable diaper according to any one of claims 1 to 6, wherein the skin-side sheet at the depressed portion has a hydrophilicity that is larger on the opening side than on the outer side of the opening.
[Claim 8] The disposable diaper according to any one of claims 1 to 7, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the non-skin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and each opening of the skin-side sheet is arranged between the elastic members that are adjacent to each other in the longitudinal direction.
[Claim 9] The disposable diaper according to any one of claims 1 to 8, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the skin-side sheet and the non-skinside sheet are bonded to each other via an adhesive, and the portion in which the adhesive is arranged overlaps the bonded portion of the skin-side sheet.
[Claim 10]

The disposable diaper according to any one of claims 1 to 9, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and the bonded portion is such that the portion that is bonded is in the form of a film.
[Claim 11] The disposable diaper according to any one of claims 1 to 10, wherein the disposable diaper has a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and the skin-side sheet is formed of a folded-back portion of the outer sheet.
[Claim 12] The disposable diaper according to any one of claims 1 to 11, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and the openings are intermittently arranged throughout the skin-side sheet.
[Claim 13] The disposable diaper according to any one of claims 1 to 12, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portions respectively have the openings and are intermittently arranged in a row along the longitudinal direction, and a plurality of bonded portion rows formed of the plurality of bonded portions are arranged at intervals along the lateral direction.
[Claim 14] The disposable diaper according to claim 13, wherein an interval between the bonded portions that are adjacent to each other in the longitudinal direction and that form the bonded portion rows extending in the longitudinal direction is from 1 to 20 mm.
[Claim 15] The disposable diaper according to claim 13 or 14, wherein an interval between the bonded portion rows that are adjacent to each other in the lateral direction is from 4 to 20 mm.
[Claim 16] The disposable diaper according to any one of claims 1 to 15, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and, when a depth of the depressed portion at an inner peripheral wall of the bonded portion is taken as d3, a thickness at a position that is distanced outward from the inner peripheral wall of the bonded portion by a distance that is 0.50 times the depth d3 is from 20 to 75% of a thickness d2 of portions other than the depressed portion.
[Claim 17] The disposable diaper according to any one of claims 1 to 16, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and a thickness at a position that is distanced outward from an inner peripheral wall of the bonded portion by a distance that is 1.5 times the depth d3 is from 55 to 95% of a thickness d2 of portions other than the depressed portion.
[Claim 18] The disposable diaper according to any one of claims 1 to 17, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, the bonded portion of the skin-side sheet is such that an inner peripheral wall of the bonded portion has a thickness d5 of from 10 to 60 pm.
[Claim 19] The disposable diaper according to any one of claims 1 to 18, wherein each opening of the skin-side sheet has a diameter LI of from 0.5 to 3 mm.
[Claim 20] The disposable diaper according to any one of claims 1 to 19, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and an inner peripheral wall of the bonded portion has a thickness d5 that is from 1/50 to 1/10 of a diameter LI of the opening.
[Claim 21] The disposable diaper according to any one of claims 1 to 20, wherein the openings of the skin-side sheet are such that an opening area of one opening is from 0.5 to 5 mm².
[Claim 22] The disposable diaper according to any one of claims 1 to 21, wherein a proportion of an area of all openings with respect to a total area of the skin-side sheet is from 1 to 15%.
[Claim 23] The disposable diaper according to any one of claims 1 to 22, wherein each opening of the skin-side sheet is formed in a thin region and an opening-side thin region, the thin region is a portion included inside an outer periphery of the depressed portion and having a thickness that is 70% or less of a thickness d2 of portions other than the depressed portion in the skin-side sheet, and the opening-side thin region is a portion of the thin region having a thickness that is 40% or less of the thickness d2.
[Claim 24] The disposable diaper according to any one of claims 1 to 23, wherein a thickness d2 of portions other than the depressed portion in the skin-side sheet is from 100 to 600 pm.
[Claim 25] The disposable diaper according to any one of claims 1 to 24, wherein a thin region of an outer periphery of each opening in the depressed portions is formed in the shape of a ring as in the case of the outer periphery.
[Claim 26] The disposable diaper according to any one of claims 1 to 25, wherein a thin region of each depressed portion has a diameter L2 that is from 1.5 to 3 times of a diameter LI of the opening.
[Claim 27] The disposable diaper according to any one of claims 1 to 26, wherein the skin-side sheet has a basis weight that is from 9 to 30 g/m².
[Claim 28] The disposable diaper according to any one of claims 1 to 27, wherein the rear waist flap and the front waist flap are formed by joining and fixing the non-skin-side sheet and an outer sheet to each other via a plurality of joined regions arranged in a dispersed manner.
[Claim 29] The disposable diaper according to any one of claims 1 to 28, wherein a hydrophobic outer sheet is provided on the non-skin-facing surface side of the non-skinside sheet, joined regions of the non-skin-side sheet and the outer sheet are intermittently arranged in a row along the longitudinal direction in a region spanning from a waist elasticized portion to a below-waist lower elasticized portion of each of the front region and the rear region, and a plurality of joined region rows formed of the plurality of joined regions are arranged at intervals along the lateral direction.
[Claim 30] The disposable diaper according to claim 29, wherein an interval between the joined regions that are adjacent to each other in the longitudinal direction and form the joined region rows extending in the longitudinal direction is from 1 to 20 mm.
[Claim 31] The disposable diaper according to claim 29 or 30, wherein an interval between the joined region rows that are adjacent to each other in the lateral direction is from 4 to 20 mm.
[Claim 32] The disposable diaper according to any one of claims 1 to 31, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the non-skin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and the skin-side sheet has a bonded portion in each of the depressed portions, and the bonded portion, and the opening of the skin-side sheet are arranged between the elastic members that are adjacent to each other in the longitudinal direction.
[Claim 33] The disposable diaper according to any one of claims 1 to 32, wherein the disposable diaper includes a hydrophobic outer sheet on the non-skin-facing surface side of the non-skin-side sheet, and a plurality of elastic members arranged in a state of being stretched in the lateral direction of the disposable diaper between the non-skin-side sheet and the outer sheet and intermittently arranged along the longitudinal direction of the disposable diaper, and the skin-side sheet has a bonded portion in each of the depressed portions, and when viewed in a cross-section of a gather portion formed through contraction of the elastic members, 60% to 100% of all of the bonded portions are arranged from a position that is at half a depth d4 of depressions depressed toward the non-skin side of the skin-side sheet to the projection side.
[Claim 34] The disposable diaper according to any one of claims 1 to 33, wherein an inter-fiber distance between constituent fibers forming the skin-side sheet in each depressed portion is smaller on the opening side than on the outer side of the opening.
[Claim 35] The disposable diaper according to any one of claims 1 to 34, wherein an inter-fiber distance between fibers forming an opening-side thin region with a thickness that is 40% or less of a thickness d2 of portions other than the depressed portion, in an outer periphery of the opening, inside a thin region with a thickness that is 70% or less of the thickness d2, is 4/5 or less of an inter-fiber distance between fibers forming a portion near an outer edge of the depressed portion at the outer periphery.
[Claim 36]

The disposable diaper according to any one of claims 1 to 35, wherein the skin-side sheet forming an opening-side thin region with a thickness that is 40% or less of a thickness d2 of portions other than the depressed portion, in an outer periphery of the opening, inside a thin region with a thickness that is 70% or less of the thickness d2, has a contact angle with respect to ion exchange water that is 120° or less.
[Claim 37] The disposable diaper according to any one of claims 1 to 36, wherein the skin-side sheet forming a portion near an outer edge of the depressed portion in an outer periphery of the opening has a contact angle with respect to ion exchange water that is 120° or greater.
[Claim 38] The disposable diaper according to any one of claims 1 to 37, wherein the skin-side sheet includes, in each depressed portion, a bonded portion in which constituent fibers of the skin-side sheet are bonded to each other, and a difference between a contact angle between a portion near the bonded portion and ion exchange water and a contact angle between a portion near an outer edge of the depressed portion in an outer periphery of the opening and ion exchange water is 10° or greater.
[Claim 39] The disposable diaper according to any one of claims 1 to 38, wherein the non-skin-side sheet has a basis weight that is from 10 to 50 g/m².
[Claim 40] The disposable diaper according to any one of claims 1 to 39, wherein the non-skin-side sheet is such that portions thereof other than the depressed portions have a thickness of from 100 to 800 μιη.
[Claim 41] The disposable diaper according to any one of claims 1 to 40, wherein the non-skin-side sheet has a hydrophilic fiber content with respect to all constituent fibers of from 70 to80% by mass.
[Claim 42]

The disposable diaper according to any one of claims 1 to 41, wherein the non-skin-side sheet has a Klemm water absorption height at 30 mm width, as measured according to JIS P 8141, of 20 mm or greater at 60 seconds.
[Claim 43] The disposable diaper according to any one of claims 1 to 42, wherein the non-skin-side sheet has a saturated water-absorption amount of ion exchange water of 75 g/m² or greater.