GB2579975A

GB2579975A - Pull-up absorbent article

Info

Publication number: GB2579975A
Application number: GB2003616.6A
Authority: GB
Inventors: Tadai Tomohiro; Kawaguchi Hiroko; Okuda Yasuyuki
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2017-08-31
Filing date: 2017-08-31
Publication date: 2020-07-08
Anticipated expiration: 2037-08-31
Also published as: GB2579975B; DE112017007983T5; JPWO2019043885A1; CN110891537B; RU2736267C1; WO2019043885A1; GB202003616D0; CN110891537A; JP6982084B2

Abstract

This pull-up absorbent article (1) is provided with a belly-side section (2A), a back-side section (2B), and an absorbent body (3). The belly-side section (2A) and the back-side section (2B) respectively have side panels (29A, 29B) extending further outward in a width direction (Y) than side edges of the absorbent body (3). The side panels (29A, 29B) have composite sheets provided with outer sheets (22) and inner sheets (23). The composite sheets are stretchable in the width direction (Y) and have a plurality of rows of gathers (29a, 29b) arranged in the width direction (Y) and extending in a longitudinal direction (X). In the side panels (29A, 29B), the gathers extending in the longitudinal direction (X) are offset in the width direction (Y) at predetermined positions in the longitudinal direction (X).

Description

DESCRIPTION

Title of the Invention: PULL-UP ABSORBENT ARICLE

Technical Field [0001]

The present invention relates to a pull-on absorbent article.

Background Art

[0002] To pull-on absorbent articles including pull-on disposable diapers, elasticity may be imparted over a waist region and a below-waist region in the width direction in order to improve the fitting properties to the body of a wearer. To impart elasticity, typically, a plurality of elastic members in a stretched state are so fixed as to extend in the width direction to a sheet constituting the area to which elasticity is intended to be imparted. The elastic members fixed in such a manner form, in the width direction, a plurality of creases each extending in the longitudinal direction on the sheet. For example, the applicant has disclosed a pull-on disposable diaper including an outer cover that includes an outer sheet constituting an outer surface of a diaper, an inner sheet provided on an inner surface of the outer sheet, and a plurality of filamentous elastic members provided in a stretched state in a lateral direction between the outer sheet and the inner sheet. The outer sheet and the inner sheet are joined together in a plurality of joined regions, the elastic members are arranged so as not to pass through the joined regions, and thus the outer cover has a plurality of creases each extending in the longitudinal direction over the plurality of elastic members (see Patent Literature 1).

Citation List Patent Literatures [0003] Patent Literature 1: JP 2008-131968 A

Summary of Invention [0004]

The present invention provides a pull-on absorbent article including a front portion to be placed on a front of a wearer, a rear portion to be placed on a rear of the wearer, an absorbent assembly, and a pair of side seals that are formed on lateral side edge portions of the front portion and the rear portion by joining the front portion and the rear portion.

Each of the front portion and the rear portion includes side panels extending outward in a width direction from lateral side edges of the absorbent assembly.

Each side panel includes a composite sheet including an outer sheet and an inner sheet, and the composite sheet is stretchable in the width direction and has, in the width direction, a plurality of lines of creases extending in a longitudinal direction.

On the side panels of at least one of the front portion and the rear portion, at least some of the plurality of lines of creases which extend in the longitudinal direction do not align in the width direction on a predetermined position in the longitudinal direction.

Brief Description of Drawings [0005]

[Fig. 1] Fig. 1 is a perspective view showing a pull-on disposable diaper as an embodiment of a pull-on absorbent article of the present invention.

[Fig. 2] Fig. 2 is a plan view of the diaper shown in Fig. 1, and the diaper is in its flat-out, uncontracted state and is viewed from a skin-facing surface side.

[Fig. 3] Fig. 3 is a sectional view taken along line III-Ili in Fig. 2.

[Fig. 4] Fig. 4 is a sectional view taken along line IV-IV in Fig. 2.

[Fig. 5] Fig. 5 is a plan view of a principal part of the diaper shown in Fig. 1, and the principal part is around a side seal and is in its flat-out, uncontracted state.

[Fig. 6] Fig. 6 is a partially broken perspective view showing a principal part of a front side panel of the diaper shown in Fig. I. [Fig. 7] Fig. 7 is a schematic view showing a wearing state of the diaper shown in Fig. I_ [Fig. 8] Fig. 8 is a plan view of a principal part of a diaper in another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

[Fig. 9] Fig. 9 is a plan view of a principal part of a diaper in another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

[Fig. 10] Fig. 10 is a plan view of a principal part of a diaper in a still another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

[Fig. 11] Fig. 11 is a plan view of a principal part of a diaper in a still another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

[Fig. 12] Fig. 12 is a plan view of a principal part of a diaper in a still another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

[Fig. 13] Fig. 13 is a plan view of a principal part of a diaper in a still another embodiment of the present invention, and the principal part is around a side seal and is in its flat-out, uncontracted state (corresponding to Fig. 5).

Description of Embodiments

[0006] The body of a wearer wearing a pull-on absorbent article, especially, the body of an infant, has such a complicated shape as to protrude from the waist to the hip and to curve from the abdomen to the hypogastrium. Currently, industrially manufactured pull-on absorbent articles, however, typically have a substantially cylindrical shape, and thus when such an article is intended to be fitted with the body of a wearer wearing the article, the creases may be distorted to conversely deteriorate the fitting properties, or the wearing comfort may get worse. The present invention is therefore intended to provide a pull-on absorbent article that overcomes such disadvantages.

[0007] The present invention will now be described on the basis of preferred embodiments thereof with reference to drawings. Fig. 1 and Fig. 2 show a pull-on disposable diaper 1 as an embodiment of a pull-on absorbent article of the present invention. The diaper 1 includes a front portion A to be placed on the front of a wearer wearing the diaper and a rear portion B to be placed on the rear of the wearer. The front portion A and the rear portion B extend from a crotch portion C therebetween in a front-to-rear direction as the longitudinal direction X. The diaper 1 further includes an absorbent assembly 3. The absorbent assembly 3 has a substantially rectangular shape having a longitudinal direction X from the front portion A of the diaper 1 to the rear portion B and having a width direction Y orthogonal thereto, and the longitudinal direction X of the absorbent assembly 3 is coincident with the longitudinal direction X of the diaper 1.

[0008] The diaper 1 includes a front panel 2A constituting the front portion A and a rear panel 2B constituting the rear portion B. The aforementioned absorbent assembly 3 bridges the front panel 2A and the rear panel 2B and is fixed to the panels 2A, 2B. The diaper 1 includes a pair of side seals S, S that are formed by joining side regions including lateral side edges 2a1, 2a1 of the front panel 2A constituting the front portion A and side regions including lateral side edges 2b1, 2b1 of the rear panel 2B constituting the rear portion B. The diaper 1 further includes a waist opening WO and a pair of leg openings LO, LO.

[0009] As shown in Fig. 2 and Fig. 3, the absorbent assembly 3 includes a liquid permeable topsheet 31, a liquid impermeable or water repellent backsheet 32, and a liquid-retentive absorbent member 33 interposed between the sheets 31, 32. The absorbent member 33 includes an absorbent core 331 including a fiber aggregate such as pulp fibers and a nonwoven fabric or an absorbent core 331 in which such a fiber aggregate holds water absorbing polymer particles and a core-wrap sheet 332 covering the absorbent core 331.

[0010] As shown in Fig. 2 and Fig. 3, leak-proof cuffs 34, 34 extending in the longitudinal direction X are provided on both sides in the width direction Y of the absorbent assembly 3. The leak-proof cuffs 34 are made from a liquid resistant or water repellent and breathable sheet member. In the vicinity of the free end of each leak-proof cuff 34, leakproof cuff elastic members 35 are provided in a stretched state. When a wearer wears the diaper 1, the leak-proof cuff elastic members 35 shrink to raise the leak-proof cuffs 34 toward the body of the wearer. Accordingly, a liquid is effectively prevented from leaking out of the absorbent assembly 3 from the lateral side edges.

[0011] As shown in Fig. 3, the absorbent assembly 3 includes, at the non-skin-facing surface side of the absorbent assembly 3 in the crotch portion C, an outer sheet 36 on the backsheet 32. The outer sheet 36 is used for reinforcing the strength of the backsheet 32 or for improving the texture of the diaper 1 Hence, for example, a nonwoven fabric or a film can be used as the outer sheet 36.

[0012] The absorbent assembly 3 includes leg cuffs 37, 37 extending in the longitudinal direction X, outside the respective leak-proof cuffs 34 in the width direction Y. To the free end of each leg cuff 37, leg cuff elastic members 38 extending in the longitudinal direction X are attached in a stretched state. The leg cuffs 37 are to fit with the legs of a wearer wearing the diaper 1.

[0013] As shown in Fig. 2 and Fig. 4, the absorbent assembly 3 overlaps with the rear panel 2B in one end region in the longitudinal direction X. In the overlapping region, both are fixed through an adhesive 39. Similarly, the absorbent assembly 3 overlaps with the front panel 2A in the other end region in the longitudinal direction X, and both are fixed through an adhesive (not shown) in the overlapping region.

[0014] As shown in Fig. 2, each of the front panel 2A and the rear panel 2B has a substantially rectangular shape. These panels 2A, 2B have substantially the same dimension in the width direction Y, and the rear panel 2B has a greater dimension in the longitudinal direction X than that of the front panel 2A. While the upper ends of the lateral side edges 2a1 of the panel 2A are allowed to be coincident with those of the corresponding lateral side edges 2b1 of the panel 2B, the side regions are joined to form side seals S. Hence, the length of each side seal S in the longitudinal direction Xis the same as the length of the front panel 2A in the longitudinal direction X. Meanwhile, when viewed in the longitudinal direction X, the rear panel 2B is divided into a region with the side seals S and a region extending from the side seals S toward the crotch portion C. In the following description, when the rear panel 2B is viewed in the longitudinal direction X, the region with the side seals S is called a rear main portion 20b, and the region extending downward from the side seals S is called a rear extension portion 21b. Of the rear extension portion 21b, the regions located outside the lateral side edges of the absorbent assembly 3 in the width direction Y are hip covering portions that cover the hip of a wearer wearing the diaper 1.

[0015] The front portion A and the rear portion B of the diaper 1 include front side panels 29A and rear side panels 29B, respectively, each extending outward in the width direction Y from an imaginary line 3b that extends in the longitudinal direction and passes on the corresponding lateral side edge 3a of the absorbent assembly 3. Each front side panel 29A is located, in terms of width direction Y, between the corresponding lateral side edge 2a1 of the front panel 2A and the corresponding lateral side edge 3a of the absorbent assembly 3. In terms of longitudinal direction X, the front side panel 29A is located between one end edge 2a2 of the front panel 2A and the other end edge 2a3. Each rear side panel 29B is located, in terms of width direction Y, between the corresponding lateral side edge 2b1 of the rear panel 2B and the corresponding lateral side edge 3a of the absorbent assembly 3. In terms of longitudinal direction X, the rear side panel 29B is located from an end edge 2b2 of the rear panel 2B at the waist opening side to the boundary between the rear main portion 20b and the rear extension portion 21b.

[0016] The front side panels 29A and the rear side panels 29B partly constitute the front panel 2A and the rear panel 2B, respectively. The front panel 2A including the front side panels 29A includes a composite sheet including an outer sheet 22 constituting the outer surface of the diaper and an inner sheet 23 provided at the inner surface side of the outer sheet 22. Similarly, the rear panel 2B including the rear side panels 29B includes a composite sheet including the outer sheet 22 constituting the outer surface of the diaper and the inner sheet 23 provided at the inner surface side of the outer sheet 22. As each of the outer sheet 22 and the inner sheet 23, for example, a non-elastic sheet can be used. As one of the outer sheet 22 and the inner sheet 23, an elastic sheet can be used. For example, when an elastic sheet is used as the outer sheet 22, and a non-elastic sheet is used as the inner sheet 23, creases are formed only on the inner sheet 23, and thus fitting properties and breathability are improved advantageously. When both the outer sheet 22 and the inner sheet 23 are elastic sheets, the elastic sheets can have different stretch ratios.

[0017] The composite sheets constituting the front side panels 29A and the rear side panels 29B include a plurality of elastic members 24 that are provided between the outer sheet 22 and the inner sheet 23 and extend in the width direction Y. Each elastic member 24 is fixed in a stretched state. Accordingly, the composite sheets including the front side panels 29A and the rear side panels 2911 are stretchable in the width direction Y Of the elastic members 24, elastic members in regions 24a overlapping with the absorbent assembly 3 are so processed as not to express elasticity. Examples of such a process include, but are not necessarily limited to, a process of finely cutting elastic members 24 in the regions 24a.

[0018] As shown in Fig. 2 and Fig. 5, in each front side panel 29A, the outer sheet 22 and the inner sheet 23 are joined at joined regions 25, 27 that are intermittently formed in the longitudinal direction X and the width direction Y of the side panel 29A. Elastic members 24 are so arranged as not to pass through the joined regions 25, 27. The elastic members 24 are joined neither to the outer sheet 22 nor to the inner sheet 23 in the region between the respective ends in the width direction Y and are fixed to the outer sheet 22 and the inner sheet 23 only at the respective ends in the width direction Y. Fig. 5 is a plan view of a principal part of the diaper 1 shown in Fig. 1, and the principal part is around a side seal S and is in its flat-out, uncontracted state.

[0019] Similarly, in each rear side panel 29B, the outer sheet 22 and the inner sheet 23 are joined at joined regions 26, 28 that are intermittently formed in the longitudinal direction X and the width direction Y of the side panel 29B. Elastic members 24 are so arranged as not to pass through the joined regions 28. The elastic members 24 are joined neither to the outer sheet 22 nor to the inner sheet 23 in the region between the respective ends in the width direction Y and are fixed to the outer sheet 22 and the inner sheet 23 only at the respective ends in the width direction Y [0020] The joined regions 25, 27 and the joined regions 26, 28 can be formed, for example, with various adhesives such as a hot melt adhesive or by fusing such as heat sealing. When a hot melt adhesive is used, a stripe coater is preferably used for coating, or summits, spirals, or the like may be coated in the longitudinal direction X. When heat sealing is performed, the joined regions may continue, but from the viewpoint of allowing the side panels 29A, 29B to maintain softness and of improving the breathability, the joined regions are preferably intermittently formed in the longitudinal direction X. [0021] A plurality of the joined regions 25 formed on the front side panel 29A are so arranged as to form joined region straight lines 25L in the longitudinal direction X of the front side panel 29A. A plurality of the joined region lines 25L are formed at intervals over the width direction Y of the front side panel 29A Similarly, a plurality of the joined regions 27 are so arranged as to form joined region straight lines 27L in the longitudinal direction X of the front side panel 29A. A plurality of the joined region lines 27L are formed at intervals over the width direction Y of the front side panel 29A [0022] A plurality of the joined regions 26 formed on the rear side panel 29B are so arranged as to form joined region straight lines 26L in the longitudinal direction X of the rear side panel 29B. A plurality of the joined region lines 26L are formed at intervals over the width direction Y of the rear side panel 29B. Similarly, a plurality of the joined regions 28 are so arranged as to form joined region straight lines 28L in the longitudinal direction X of the rear side panel 29B. A plurality of the joined region lines 28L are formed at intervals over the width direction Y of the rear side panel 29B.

[0023] On the front side panel 29A, when the elastic members 24 provided in a stretched state shrink in a relaxed state or in a natural state of the diaper 1, the outer sheet 22 between joined region lines 25L, 25L adjacent to each other in the width direction Y is so deformed as to rise outward, and the inner sheet 23 is so deformed as to rise toward the body of a wearer, as shown in Fig. 6. Between the adjacent joined region lines 25L, 25L, creases 29a, 29a of the outer sheet 22 and the inner sheet 23 are formed. In other words, each of the outer sheet 22 and the inner sheet 23 forms a plurality of lines of creases 29a extending continuously across a plurality of elastic members 24. Between the outer sheet 22 and the inner sheet 23, hollow portions 2FI each surrounded by a crease 29a and a crease 29a are formed. The creases 29a and the hollow portions 2H extend in the longitudinal direction X of the side panel 29A.

[0024] Similarly, between the joined region lines 27L, 27L adjacent in the width direction Y, the outer sheet 22 is so deformed as to rise outward, and the inner sheet 23 is so deformed as to rise toward the body of a wearer, as shown in Fig. 6. Between the adjacent joined region lines 27L, 27L, creases 29b, 29b of the outer sheet 22 and the inner sheet 23 are formed. Between the outer sheet 22 and the inner sheet 23, hollow portions (not shown) each surrounded by a crease 29b and a crease 29b are formed. The creases 29b and the hollow portions (not shown) extend in the longitudinal direction X of the side panel 29A.

[0025] In a similar manner to the front side panel 29A, as for the rear side panel 29B, the outer sheet 22 between the joined region lines 26L, 26L and the joined region lines 28L, 28L is so deformed as to rise outward, and the inner sheet 23 is so deformed as to rise toward the body of a wearer. Accordingly, between the adjacent joined region lines 26L, 26L and between the adjacent joined region lines 28L, 28L, creases of the outer sheet 22 and the inner sheet 23 are formed (not shown), and hollow portions are also formed (not shown). The creases (not shown) and the hollow portions (not shown) extend in the longitudinal direction X of the side panel 29B.

[0026] As shown in Fig. 2 and Fig. 5, the joined region lines 25L and the joined region lines 27L formed on the front side panel 29A each extend in the longitudinal direction X, but the joined region lines 25L, 27L do not align with each other and do not align in the width direction Y. Consequently, as shown in Fig. 6, the creases 29a formed by the joined region lines 25L do not align with the creases 29b formed by the joined region lines 27L, and the creases 29a, 29b do not align with each other in the width direction Y. In other words, on the front side panel 29A, the creases 29a and the creases 29b do not align in the width direction Y on a predetermined position in the longitudinal direction X and lack continuity in the longitudinal direction X. In the present embodiment, the predetermined position is on a boundary P between the joined region lines 25L and the joined region lines 27L as shown in Fig. 5 and Fig. 6. The boundary P between the joined region lines 25L and the joined region lines 27L linearly extends in the width direction Y. [0027] Also on the rear side panel 29B, as shown in Fig. 2 and Fig. 5, the joined region lines 26L and the joined region lines 28L formed on the rear side panel 29B each extend in the longitudinal direction X, but the joined region lines 26L, 28L do not align with each other and do not align in the width direction Y. Consequently, creases (not shown) formed by the joined region lines 26L do not align with creases (not shown) formed by the joined region lines 28L, and the creases do not align with each other in the width direction Y. In other words, on the rear side panel 29B, the creases do not align in the width direction Y on a predetermined position (see Fig. 5) in the longitudinal direction X and lack continuity in the longitudinal direction X. In the present embodiment, the predetermined position is on a boundary Q between the joined region lines 26L and the joined region lines 28L as shown in Fig. 5. The boundary Q between the joined region lines 26L and the joined region lines 28L linearly extends in the width direction Y. The boundary Q and the above boundary P are on the same position when the diaper 1 is viewed in the longitudinal direction X. The boundary Q and the boundary P are on the same straight line extending in the width direction Y. The boundary P and the boundary Q are preferably located on any position in a region with the side seal S when the diaper 1 is viewed in the longitudinal direction X. The "same position" means that the distance from the end edge 2a2 of the front panel 2A to the boundary P is equal to the distance from the end edge 2b2 of the rear panel 2B to the boundary Q, and the difference of these distances is not more than 10 mm for infant diapers or is not more than 20 mm for adult diapers.

[0028] In the present embodiment, a crease lacking continuity in the longitudinal direction X on the boundary P, Q means that a roof of the crease bends on the boundary P, Q. In order to allow creases to lack continuity in the longitudinal direction X on the boundaries P, Q, the non-alignment degree in the width direction Y between the joined region lines 25L and the joined region lines 27L and the non-alignment degree in the width direction Y between the joined region lines 26L and the joined region lines 28L are preferably each independently set at 1 mm or more and 20 mm or less, more preferably set at 2 mm or more and 15 mm or less, and even more preferably set at 3 mm or more and 10 mm or less.

[0029] When a wearer wears the diaper 1 of the embodiment, the side panels 29A, 29B deform corresponding to a body unevenness of the wearer. According to the deformation, the creases formed in the longitudinal direction X on the front side panels 29A and the rear side panels 29B also bend on the boundaries P, Q. When the boundaries P, Q are on the same position in the wearing state, bending portions continue on the boundaries P, Q as shown in Fig. 7. As a result, the diaper 1 has satisfactory fitting properties when worn and exhibits satisfactory wearing comfort. From this viewpoint, the non-alignment position of the creases in the width direction Y is preferably identical between the front side panels 29A and the rear side panels 29B when the diaper 1 is worn.

[0030] The positions of the boundaries P, Q can be appropriately set in consideration of fitting properties and the like of the side panels 29A, 29B in the diaper 1. For example, as shown in Fig. 2, when each of the side panels 29A, 29B is divided in the longitudinal direction X into a waist region D1 including the waist opening WO of the diaper 1, a crotch region D2 located at the crotch portion side, and a middle region D3 located between these regions, at least some of the plurality of lines of creases extending in the longitudinal direction X do not preferably align in the width direction Y in the middle region D3 to lack the continuity of the creases in the longitudinal direction X, in each of the side panels 29A, 29B. As for the division into the waist region Dl, the crotch region D2, and the middle region D3 in each of the side panels 29A, 29B, for example, the middle region D3 is preferably a region 15% or more and 85% or less distant from the lower end of the side seal, the waist region D1 is preferably a region closer to the waist opening than the middle region D3, and the crotch region D2 is preferably a region closer to the crotch portion C than the middle region D3.

[0031] The boundaries P, Q on which the creases do not align in the width direction Y are preferably each independently 15% or more distant from the lower end of the side seal relative to the length in the longitudinal direction X of the side seal S, particularly 20% or more distant, and especially 25% or more distant. The boundaries P, Q are preferably each independently 85% or less distant from the lower end of the side seal S, particularly 70% or less distant, and especially 60% or less distant. Specifically, the boundaries P, Q are preferably each independently in an area 15% or more and 85% or less distant from the lower end of the side seal S, particularly in an area 20% or more and 7O% or less distant, and especially in an area 25% or more and 60% or less distant. By providing the boundaries P, Q within the area, the diaper 1 has higher fitting properties when worn, and the diaper 1 exhibits higher wearing comfort.

[0032] At least some of the creases formed on the front side panels 29A and the rear side panel 29B may not be aligned in the width direction Y on a predetermined position in the longitudinal direction X, and the creases may lack continuity in the longitudinal direction X. Alternatively, from the viewpoint of further improving the fitting properties when the diaper 1 is worn and of further improving the wearing comfort of the diaper 1, creases may be formed over the entire region in the width direction Y of the front side panels 29A and the rear side panels 29B, the creases may not be aligned in the width direction Y on a predetermined position in the longitudinal direction X over the entire region in the width direction Y of the side panels 29A, 29B, and the creases may lack continuity in the longitudinal direction X [0033] As shown in Fig. 5, on the front side panel 29A with the boundary P on which the creases do not align in the width direction Y, the pitch L I of creases closer to the waist opening than the boundary P is identical with the pitch L2 of creases closer to the crotch portion than the boundary P An identical pitch means that the pitch Ll is equal to the pitch L2, and the difference between the pitches is not more than 2 mm for infant diapers or is not more than 4 mm for adult diapers (the same is applied to the pitch L3 and the pitch L4 described later). Also on the rear side panel 29B with the boundary Q on which the creases do not align in the width direction Y, the pitch L3 of creases closer to the waist opening than the boundary Q is identical with the pitch L4 of creases closer to the crotch portion than the boundary P. With this structure, the diaper 1 has higher fitting properties when worn, and the diaper 1 exhibits higher wearing comfort. In this case, the pitch Ll may be the same as or different from the pitch L3. Creases are formed when the diaper 1 is in a relaxed state, but Fig. 5 shows the diaper 1 in its uncontracted state, and the pitches LI to L4 represent pitches of joined region lines. Hence, the pitch differs from the pitch of actual creases. However, the pitch of creases typically correlates with the pitch of joined region lines, and thus the pitch of joined region lines has been described for the pitch of creases [0034] The pitch Ll on the front side panel 29A and the pitch L3 on the rear side panel 29B are preferably each independently 1 mm or more and 20 mm or less, more preferably 3 mm or more and 15 mm or less, and even more preferably 5 mm or more and 10 mm or less on the condition that the non-alignment degree in the width direction Y between the joined region lines 25L and the joined region lines 27L and the non-alignment degree in the width direction Y between the joined region lines 26L and the joined region lines 28L are within the above ranges.

[0035] Fig. 8 to Fig. 13 show other embodiments of the pull-on absorbent article of the present invention. These embodiments will be described on different points from the embodiment shown in Fig. 1 to Fig. 7, and to points not specifically described, the description for Fig. 1 to Fig. 7 will be appropriately applied. In Fig. 8 to Fig. 13, identical members to those in Fig. 1 to Fig. 7 are indicated by the same signs.

[0036] In the embodiment shown in Fig. 1 to Fig. 7, the creases lack continuity in the longitudinal direction X in both the front side panel 29A and the rear side panel 29B. Alternatively, creases may lack continuity in the longitudinal direction X only in one of the front side panel 29A and the rear side panel 29B. For example, in an embodiment shown in Fig. 8, in a front side panel 29A, the formation positions of joined region lines 25L do not align in the width direction Y from the formation positions of joined region lines 27L so that creases lack continuity in the longitudinal direction X on a boundary R In a rear side panel 29B, only joined region lines 26L are formed over the entire region in the longitudinal direction X, and thus crease formed by the joined region lines 26L maintain continuity in the longitudinal direction X in the entire region of the rear side panel 29B.

[0037] In the embodiment shown in Fig. 1 to Fig. 7, the boundary P, on which creases lack continuity in the longitudinal direction X on the front side panel 29A, is on the same position as the boundary Q, on which creases lack continuity in the longitudinal direction X on the rear side panel 29B, when the diaper is viewed in the longitudinal direction X. Alternatively, a boundary P and a boundary Q may be provided on different positions as shown in Fig. 9 when a diaper is viewed in the longitudinal direction X. In an embodiment shown in the figure, a boundary P is closer to the waist opening than a boundary Q. In this case, the boundary P is preferably located in an area 5% or more and 70% or less distant from the lower end of the side seal S, more preferably in an area 10% or more and 60% or less distant, and even more preferably in an area 15% or more and 50% or less distant. The boundary Q is preferably located in an area 10% or more and 80% or less distant from the lower end of the side seal S, more preferably in an area 15% or more and 70% or less distant, and even more preferably in an area 20% or more and 60% or less distant, on the condition that the boundary Q is closer to the crotch portion than the boundary P The present embodiment achieves higher fitting properties when the diaper is worn, and the diaper 1 exhibits higher wearing comfort advantageously.

[0038] In the embodiment shown in Fig. 1 to Fig. 7, in each of the front side panel 29A and the rear side panel 29B, a crease lacks continuity in the longitudinal direction X only at one position or only on the boundary P or the boundary Q, but a crease may lack continuity at a plurality of positions. For example, as shown in Fig. 10, the formation positions of joined region lines 25L do not align in the width direction Y from the formation positions of joined region lines 27L so that creases lack continuity in the longitudinal direction X on boundaries P1 and P2 in a front side panel 29A. Specifically, on the boundary Pt, the formation positions of upper joined region lines 25L do not align in the width direction Y from the formation positions of lower joined region lines 27L. On the boundary P2, the formation positions of upper joined region lines 27L do not align in the width direction Y from the formation positions of lower joined region lines 25L [0039] Similarly, in a rear side panel 29B, the formation positions of joined region lines 26L do not align in the width direction Y from the formation positions of joined region line 28L so that creases lack continuity in the longitudinal direction X on boundaries Q1 and Q2. Specifically, on the boundary Ql, the formation positions of upper joined region lines 26T. do not align in the width direction Y from the formation positions of lower joined region line 28L. On the boundary Q2, the formation positions of upper joined region lines 26L do not align in the width direction Y from the formation positions of lower joined region lines 26L. The present embodiment achieves higher fitting properties when the diaper is worn, and the diaper 1 exhibits higher wearing comfort advantageously (the diaper 1 has such a shape as to fit with the body more closely).

[0040] In the embodiment shown in Fig. 10, the boundary P1 formed on the front side panel 29A is on the same position as the boundary Q1 formed on the rear side panel 29B when the diaper 1 is viewed in the longitudinal direction X. Alternatively, the boundary P1 and the boundary Q1 may be formed on different positions in terms of the longitudinal direction X. The boundary P2 formed on the front side panel 29A is on the same position as the boundary Q2 formed on the rear side panel 29B. Alternatively, the boundary P2 and the boundary Q2 may be formed on different positions in terms of the longitudinal direction X. [0041] In the embodiment shown in Fig. 10, the length in the longitudinal direction of the creases between the boundary P1 and the boundary P2 and the length in the longitudinal direction of the creases between the boundary Q1 and the boundary Q2 are preferably each independently not less than 5% and not more than 60% of the length of a side seal S, more preferably not less than 10% and not more than 50%, and even more preferably not less than 15% and not more than 40%.

[0042] In an embodiment shown in Fig. 11, in a front side panel 29A with a boundary P, the pitch Lt of joined region lines 25L closer to the waist opening than the boundary P differs from the pitch L2 of joined region lines 27L closer to the crotch portion than the boundary P. Specifically, the pitch Ll is greater than the pitch L2. As a result, the pitch of creases formed by the joined region lines 25L is greater than the pitch of creases formed by the joined region lines 27L.

[0043] In a rear side panel 29B with a boundary Q, the pitch L3 of joined region lines 26L closer to the waist opening than the boundary Q differs from the pitch L4 of joined region lines 28L closer to the crotch portion than the boundary Q. Specifically, the pitch L3 is greater than the pitch L4. As a result, the pitch of creases formed by the joined region lines 26L is greater than the pitch of creases formed by the joined region lines 28L.

[0044] In the embodiment shown in Fig. 11, the pitch Ll on the front side panel 29A may be the same as or different from the pitch L3 on the rear side panel 29B. Similarly, the pitch L2 on the front side panel 29A may be the same as or different from the pitch L4 on the rear side panel 29B.

[0045] In an embodiment shown in Fig. 12, creases are not entirely formed in the region in the width direction Y of a front side panel 29A and a rear side panel 29B, and the side panels have crease unformed regions in the vicinity of a side seal S. Specifically, on the front side panel 29A, a crease unformed region M1 is formed closer to the waist opening than a boundary P, and a crease unformed region M2 is formed closer to the crotch portion than the boundary P. In the rear side panel 29B, a crease unformed region M3 is formed closer to the waist opening than a boundary Q, and a crease unformed region M4 is formed closer to the crotch portion than the boundary Q. The crease unformed regions M1 to M4 are in contact with the side seal S. The crease unformed regions M1 to M4 can be formed as follows, for example: in the regions Ml to M4, no elastic members 24 are arranged, and an outer sheet 22 and an inner sheet 23 are joined in the entire regions on the counter faces thereof [0046] In an embodiment shown in Fig. 13, a front side panel 29A and a rear side panel 29B have crease unformed zones Z1, Z2 in which no creases are formed in the width direction Y. The crease unformed zones Z1, Z2 are each a rectangular region having a length and a width greater than the length. The crease unformed zones Z1, Z2 are formed in the entire regions in the width direction Y of the front side panel 29A and the rear side panel 29B In the front side panel 29A and the rear side panel 29B, joined region lines 25L, 26L closer to the waist opening than the crease unformed zones Z1, Z2 do not align in the width direction Y from joined region lines 27L, 28L closer to the crotch portion than the zones, and the joined region lines lack continuity in the longitudinal direction X. As a result, on the front side panel 29A and the rear side panel 29B, creases closer to the waist opening than the crease unformed zones Z1, Z2 do not align in the width direction from creases closer to the crotch portion than the zones, and the creases lack continuity in the longitudinal direction X. In the present embodiment, a crease lacking continuity in the longitudinal direction X means that a roof of the crease does not continue in the crease unformed zone Z1, Z2.

[0047] The present embodiment has such advantages that the creases ensure breathability in the longitudinal direction X, the crease unformed zones Z1, Z2 ensure breathability in the width direction Y, and the diaper is more unlikely to become stuffy. This structure helps a user to catch the crease unformed zones Z1, Z2 by fingers, and thus the user can smoothly pull up the diaper advantageously. From the viewpoint of more markedly achieving the advantage, the lengths in the longitudinal direction X of the crease unformed zones Z1, Z2 are preferably each independently not less than 3% of the length in the longitudinal direction of the side seal S, more preferably not less than 5%, and even more preferably not less than 7%. The lengths in the longitudinal direction X of the crease unformed zones Z I, Z2 are preferably each independently not more than 50% of the length in the longitudinal direction of the side seal S, more preferably not more than 25%, and even more preferably not more than 20%. Specifically, the lengths in the longitudinal direction X of the crease unformed zones Z1, Z2 are preferably each independently not less than 3% and not more than 50% of the length in the longitudinal direction of the side seal S, more preferably not less than 5% and not more than 25%, and even more preferably not less than 7% and not more than 20%.

[0048] In the present embodiment, when an elastic sheet is used as the inner sheet 23, and a non-elastic sheet is used as the outer sheet 22, creases are formed only on the outer sheet 22, and thus the breathability and the easy catching of the crease unformed zones Z1, Z2 by fingers are improved advantageously.

[0049] The crease unformed zones Z1, Z2 are preferably formed in the middle region D3 described above when the diaper is viewed in the longitudinal direction X in term of improvement in fitting properties of the diaper. In particular, the crease unformed zones Z1, Z2 are preferably formed in a region that is in contact with the region from the iliac crest to the anterior superior iliac spine of a wearer wearing the diaper.

[0050] The side panels 29A, 29B preferably include, in the region other than the crease unformed zones Z1, Z2, a plurality of elastic members 24 extending in the width direction Y between an outer sheet 22 and an inner sheet 23 included in the side panels 29A, 29B and preferably include, in the crease unformed zones Z1, Z2, no elastic members 24. Such a structure is preferred because the crease unformed zones Z1, Z2 further improve the fitting properties and the wearing comfort of the diaper.

[0051] The present invention has been described on the basis of the preferred embodiments thereof, but the present invention is not limited to the above embodiments. For example, in the diaper of the above embodiments, the front portion A and the rear portion B are formed from different sheet members, and the absorbent assembly 3 is provided to bridge the sheet members. Alternatively, a single sheet member may be provided on the outer surface of the absorbent assembly from the front portion to the rear portion.

[0052] In the above embodiments, the rear extension portions 21b are formed in the rear portion B, but the rear extension portions 21b may not be formed.

[0053] The above embodiments relate to a pull-on disposable diaper. Alternatively, the present invention can be applied to other pull-on absorbent articles including disposable sanitary shorts.

[0054] In the above embodiments, both the outer sheet 22 and the inner sheet 23 rise outward to form creases. Alternatively, only one of the outer sheet 22 and the inner sheet 23 may rise outward to form creases. Alternatively, both the outer sheet 22 and the inner sheet 23 may be integrally deformed into a waveshape to form creases.

[0055] In the above embodiments, the outer sheet and the inner sheet are joined at joined regions that are intermittently formed in the longitudinal direction X and the width direction Y of the side panels, and the elastic members are arranged so as not to pass through the joined regions and are fixed at the respective ends to the sheets. Alternatively, in another embodiment, an outer sheet and an inner sheet may be joined on a plurality of lines of joined regions formed continuously in the longitudinal direction X of side panels and formed intermittently in the width direction Y, and elastic members may be fixed to the sheets so as to intersect the joined regions. Even when any embodiment is adopted, an outer sheet and an inner sheet are preferably joined at least at joined regions that are intermittently formed in the width direction of side panels, and accordingly each of the outer sheet and the inner sheet preferably forms a plurality of lines of creases extending continuously over a plurality of elastic members.

[0056] In relation to the foregoing embodiment, the present invention further discloses the following pull-on absorbent article.

< I > A pull-on absorbent article comprising: a front portion to be placed on a front of a wearer; a rear portion to be placed on a rear of the wearer; an absorbent assembly; and a pair of side seals that are formed on lateral side edge portions of the front portion and the rear portion by joining the front portion and the rear portion, wherein each of the front portion and the rear portion includes side panels extending outward in a width direction from imaginary lines that extend in a longitudinal direction and pass on lateral side edges of the absorbent assembly, each side panel includes a composite sheet including an outer sheet and an inner sheet, the composite sheet is stretchable in the width direction and has, in the width direction, a plurality alines of creases extending in the longitudinal direction, and on the side panels of at least one of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction on a predetermined position in the longitudinal direction.

[0057] <2> The pull-on absorbent article as set forth in clause 1, wherein each side panel is divided in the longitudinal direction into a waist region including a waist opening of the article, a crotch region located at a side of a crotch portion, and a middle region located between the regions, and on the side panels of at least one of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction in the middle region.

<3> The pull-on absorbent article as set forth in clause I or 2, wherein the position on which the creases do not align in the width direction is in an area 15% or more and 85% or less distant from a lower end of the side seals relative to a length in the longitudinal direction of the side seals.

<4> The pull-on absorbent article as set forth in any one of clauses 1 to 3, wherein each side panel has the creases over an entire region in the width direction, and over the entire region in the width direction of the side panel, the creases do not align in the width direction on the position.

<5> The pull-on absorbent article as set forth in any one of clauses 1 to 4, wherein the position on which the creases do not align in the width direction is a boundary, and a pitch of creases closer to the waist opening than the position is equal to a pitch of creases closer to the crotch portion than the position.

<6> The pull-on absorbent article as set forth in any one of clauses 1 to 5, wherein the side panel includes, in the width direction, a crease unformed zone in which the creases are not formed, and creases closer to the waist opening than the crease unformed zone do not align in the width direction from creases closer to the crotch portion than the crease unformed zone.

[0058] <7> The pull-on absorbent article as set forth in clause 6, wherein the lengths in the longitudinal direction of the crease unformed zones are preferably independently not less than 3% of the length in the longitudinal direction of the side seal, more preferably not less than 5%, and even more preferably not less than 7%. The lengths in the longitudinal direction of the crease unformed zones are preferably not more than 50% of the length in the longitudinal direction of the side seal, more preferably not more than 25%, and even more preferably not more than 20%.

<8> The pull-on absorbent article as set forth in clause 6 or 7, wherein the side panel includes, in a region other than the crease unformed zone, a plurality of elastic members extending in the width direction between the outer sheet and the inner sheet included in the side panel.

[0059] <9> The pull-on absorbent article as set forth in any one of clauses 1 to 8, wherein the side panel includes the outer sheet, the inner sheet, and a plurality of elastic members extending in the width direction between the sheets, the outer sheet and the inner sheet are joined at joined regions intermittently formed in the width direction of the side panel, and each of the outer sheet and the inner sheet forms the plurality of lines of creases extending over the plurality of elastic members.

<10> The pull-on absorbent article as set forth in any one of clauses 1 to 9, wherein the outer sheet and the inner sheet are joined at joined regions intermittently formed in the longitudinal direction and the width direction of the side panel, and the elastic members are so arranged in a stretched state as not to pass through the joined regions, are fixed at ends thereof to the sheets, and are joined neither to the outer sheet not to the inner sheet in a region between the ends.

<11> The pull-on absorbent article as set forth in clause 10, wherein the outer sheet is deformed to rise outward, the inner sheet is deformed to rise toward a wearer body, each of the outer sheet and the inner sheet forms creases, and between the outer sheet and the inner sheet, hollow portions surrounded by the creases are formed.

<12> The pull-on absorbent article as set forth in any one of clauses 1 to 11, wherein on the side panels of the front portion, a non-alignment degree in the width direction of the creases is set at 1 mm or more and 20 mm or less, more preferably set at 2 mm or more and 15 mm or less, and even more preferably set at 3 mm or more and 10 mm or less.

<13> The pull-on absorbent article as set forth in any one of clauses I to 12, wherein on the side panels of the rear portion, a non-alignment degree in the width direction of the creases is set at 1 mm or more and 20 mm or less, more preferably set at 2 mm or more and 15 mm or less, and even more preferably set at 3 mm or more and 10 mm or less.

<14> The pull-on absorbent article as set forth in any one of clauses 1 to 13, wherein each side panel is divided in the longitudinal direction into a waist region including the waist opening of the article, a crotch region located at the side of the crotch portion, and a middle region located between the regions, and on the side panels of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction in the middle region.

[0060] <15> The pull-on absorbent article as set forth in any one of clauses 1 to 14, wherein a boundary P that is the position on which the creases do not align in the width direction on the side panels of the front portion and a boundary Q that is the position on which the creases do not align in the width direction on the side panels of the rear portion are preferably each independently 15% or more distant from the lower ends of the side seals relative to the length in the longitudinal direction of the side seals, particularly 20% or more distant, and especially 25% or more distant. The boundaries P, Q are preferably each independently 85% or less distant from the lower end of the side seal, particularly 70% or less distant, and especially 60% or less distant.

<16> The pull-on absorbent article as set forth in clause 15, wherein the boundary Q is located closer to the crotch portion than the boundary P <17> The pull-on absorbent article as set forth in any one of clauses 1 to 1 5, wherein between the side panels of the front portion and the side panels of the rear portion, the creases do not align in the width direction on an identical position when the article is worn. <18> The pull-on absorbent article as set forth in any one of clauses 1 to 17, wherein the front portion includes a front panel, the rear portion includes a rear panel, and the rear panel has a greater length in the longitudinal direction than the front panel.

<19> The pull-on absorbent article as set forth in any one of clauses 1 to 18, wherein each of the outer sheet and the inner sheet independently includes a non-elastic sheet. <20> The pull-on absorbent article as set forth in any one of clauses 1 to 18, wherein one of the outer sheet and the inner sheet includes an elastic sheet.

[0061] <21> The pull-on absorbent article as set forth in any one of clauses 1 to 18, wherein the outer sheet includes an elastic sheet, and the inner sheet includes a non-elastic sheet. <22> The pull-on absorbent article as set forth in any one of clauses 1 to 21, wherein the creases lack continuity in the longitudinal direction on a plurality of positions.

<23> The pull-on absorbent article as set forth in clause 22, wherein on the front side panels, the creases lack continuity in the longitudinal direction on boundaries P1 and P2, on the rear side panels, the creases lack continuity in the longitudinal direction on boundaries Q1 and Q2, and a length in the longitudinal direction of the creases between the boundary P1 and the boundary P2 and a length in the longitudinal direction of the creases between the boundary Q1 and the boundary Q2 are preferably each independently not less than 5% and not more than 60% of a length of the side seals, more preferably not less than 10% and not more than 50%, and even more preferably not less than 15% and not more than 40%.

Industrial Applicability

[0062] As specifically described above, the pull-on absorbent article according to the present invention has high fitting properties and satisfactory wearing comfort in a wearing state.

Claims

CLAIMS1.A pull-on absorbent article comprising: a front portion to be placed on a front of a wearer; a rear portion to be placed on a rear of the wearer; an absorbent assembly; and a pair of side seals that are formed on lateral side edge portions of the front portion and the rear portion by joining the front portion and the rear portion, wherein each of the front portion and the rear portion includes side panels extending outward in a width direction from imaginary lines that extend in a longitudinal direction and pass on lateral side edges of the absorbent assembly, each side panel includes a composite sheet including an outer sheet and an inner sheet, the composite sheet is stretchable in the width direction and has, in the width direction, a plurality of lines of creases extending in the longitudinal direction, and on the side panels of at least one of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction on a predetermined position in the longitudinal direction.
2. The pull-on absorbent article according to claim 1, wherein each side panel is divided in the longitudinal direction into a waist region including a waist opening of the article, a crotch region located at a side of a crotch portion, and a middle region located between the regions, and on the side panels of at least one of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction in the middle region.
3. The pull-on absorbent article according to claim 1 or 2, wherein the position on which the creases do not align in the width direction is in an area 15% or more and 85% or less distant from a lower end of the side seals relative to a length in the longitudinal direction of the side seals.
4. The pull-on absorbent article according to any one of claims 1 to 3, wherein each side panel has the creases over an entire region in the width direction, and over the entire region in the width direction of the side panel, the creases do not align in the width direction on the position.
5. The pull-on absorbent article according to any one of claims 1 to 4, wherein the position on which the creases do not align in the width direction is a boundary, and a pitch of creases closer to the waist opening than the position is equal to a pitch of creases closer to the crotch portion than the position.
6. The pull-on absorbent article according to any one of claims 1 to 5, wherein the side panel includes, in the width direction, a crease unformed zone in which the creases are not formed, and creases closer to the waist opening than the crease unformed zone do not align in the width direction from creases closer to the crotch portion than the crease unformed zone.
7. The pull-on absorbent article according to claim 6, wherein a length in the longitudinal direction of the crease unformed zone is not less than 3% and not more than 50% of a length in the longitudinal direction of the side seal.
8. The pull-on absorbent article according to claim 6 or 7, wherein the side panel includes, in a region other than the crease unformed zone, a plurality of elastic members extending in the width direction between the outer sheet and the inner sheet included in the side panel.
9. The pull-on absorbent article according to any one of claims 1 to 8, wherein the side panel includes the outer sheet, the inner sheet, and a plurality of elastic members extending in the width direction between the sheets, the outer sheet and the inner sheet are joined at joined regions intermittently formed in the width direction of the side panel, and each of the outer sheet and the inner sheet forms the plurality of lines of creases extending over the plurality of elastic members.
10. The pull-on absorbent article according to any one of claims 1 to 9, wherein the outer sheet and the inner sheet are joined at joined regions intermittently formed in the longitudinal direction and the width direction of the side panel, and the elastic members are so arranged in a stretched state as not to pass through the joined regions, are fixed at ends thereof to the sheets, and are joined neither to the outer sheet not to the inner sheet in a region between the ends.
11. The pull-on absorbent article according to claim 10, wherein the outer sheet is deformed to rise outward, the inner sheet is deformed to rise toward a wearer body, each of the outer sheet and the inner sheet forms creases, and between the outer sheet and the inner sheet, hollow portions surrounded by the creases are formed.
12. The pull-on absorbent article according to any one of claims 1 to 11, wherein on the side panels of the front portion, a non-alignment degree in the width direction of the creases is set at 1 mm or more and 20 mm or less.
13. The pull-on absorbent article according to any one of claims 1 to 12, wherein on the side panels of the rear portion, a non-alignment degree in the width direction of the creases is set at 1 mm or more and 20 mm or less.
14. The pull-on absorbent article according to any one of claims 1 to 13, wherein each side panel is divided in the longitudinal direction into a waist region including the waist opening of the article, a crotch region located at the side of the crotch portion, and a middle region located between the regions, and on the side panels of the front portion and the rear portion, at least some of the plurality of lines of creases extending in the longitudinal direction do not align in the width direction in the middle region.
15. The pull-on absorbent article according to any one of claims 1 to 14, wherein a boundary P that is the position on which the creases do not align in the width direction on the side panels of the front portion and a boundary Q that is the position on which the creases do not align in the width direction on the side panels of the rear portion are each independently 15% or more distant from the lower ends of the side seals relative to the length in the longitudinal direction of the side seals, and the boundaries P, Q are each independently 85% or less distant from the lower ends of the side seals.
16. The pull-on absorbent article according to claim 15, wherein the boundary Q is located closer to the crotch portion than the boundary P.
17. The pull-on absorbent article according to any one of claims 1 to 15, wherein between the side panels of the front portion and the side panels of the rear portion, the creases do not align in the width direction on an identical position when the article is worn.
18. The pull-on absorbent article according to any one of claims 1 to 17, wherein the front portion includes a front panel, the rear portion includes a rear panel, and the rear panel has a greater length in the longitudinal direction than the front panel.
19. The pull-on absorbent article according to any one of claims 1 to 18, wherein each of the outer sheet and the inner sheet independently includes a non-elastic sheet.
20. The pull-on absorbent article according to any one of claims 1 to 19, wherein one of the outer sheet and the inner sheet includes an elastic sheet.
21. The pull-on absorbent article according to any one of claims 1 to 20, wherein the outer sheet includes an elastic sheet, and the inner sheet includes a non-elastic sheet.
22. The pull-on absorbent article according to any one of claims 1 to 21, wherein the creases lack continuity in the longitudinal direction on a plurality of positions.
23. The pull-on absorbent article according to claim 22, wherein on the front side panels, the creases lack continuity in the longitudinal direction on boundaries PI and P2, on the rear side panels, the creases lack continuity in the longitudinal direction on boundaries Q1 and Q2, and a length in the longitudinal direction of the creases between the boundary P1 and the boundary P2 and a length in the longitudinal direction of the creases between the boundary Q1 and the boundary Q2 are each independently not less than 5% and not more than 60% of a length of the side seals.