GB2585293A

GB2585293A - Pant-type absorbent article

Info

Publication number: GB2585293A
Application number: GB2013122.3A
Authority: GB
Inventors: Onda Aiko; Urayama Yusuke; Onishi Reiko
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2018-04-02
Filing date: 2019-03-06
Publication date: 2021-01-06
Anticipated expiration: 2039-03-06
Also published as: GB202013122D0; RU2757895C1; GB2585293B; WO2019193906A1; CN111405887A; CN111405887B; DE112019000549T5

Abstract

A pant-type absorbent article according to an embodiment of the present invention has an absorbent body, a waist part, and a crotch part. The absorbent body is located at the crotch. The waist part has a belly-side section and a back-side section which are located around a trunk. The crotch part is located between the belly-side section and the back-side section, and holds the absorbent body together with the belly-side section and the back-side section. At least one among the belly-side section and the back-side section is constituted by a stretchable sheet including a first region and a second region located on a vertically upper side in the vertical direction perpendicular to the circumferential direction of the trunk. The stretchable sheet is constituted by including an elastic resin and a nonwoven fabric layer including the elastic resin, circumferential shrinkage stresses thereof differ in the first region and the second region, and the dimensions of the first region and the second region are the same in the circumferential direction in a natural state.

Description

Title of the Invention: PANT-TYPE ABSORBENT ARTICLE

Field of the Invention

[0001] The present invention relates to a pant-type absorbent article such as a disposable diaper. Background of the Invention [0002] Pant-type absorbent articles including an absorbent member and an exterior member that fixes the absorbent member, such as diapers, include one using a stretchable non-woven fabric for a waist portion of the exterior member for the purpose of improving fitting property around the trunk of a wearer, for example (see, for example, Patent Literature 1).

Citation List Patent Literature [0003] Patent Literature 1: Japanese Patent Application Laid-open No. 2008-106378

Summary of the Invention

[0004] A pant-type absorbent article according to one embodiment of the present invention comprises an absorbent member, a waist portion, and a crotch portion.

The absorbent member is positioned in a crotch.

The waist portion includes an abdominal portion and a dorsal portion that are positioned around a trunk.

The crotch portion is positioned between the abdominal portion and the dorsal portion and holds the absorbent member together with the abdominal portion and the dorsal portion. At least one of the abdominal portion and the dorsal portion includes a stretchable sheet, the stretchable sheet including a first region and a second region, the second region being positioned on an upper side of the first region in an up-down direction orthogonal to a circumferential direction of the trunk.

The stretchable sheet includes an elastic resin and a non-woven fabric layer that contains the elastic resin. The first region and the second region have mutually different contraction stresses in the circumferential direction. The first region and the second region have an equal dimension in the circumferential direction in a natural state.

[0005] A stretchable sheet according to one embodiment of the present invention comprises a plurality of elastic filaments and two non-woven fabrics.

The plurality of elastic filaments are stretchable in a first direction.

The two non-woven fabrics are disposed facing each other via the plurality of elastic filaments.

The non-woven fabric includes a plurality of Projections that are intermittently disposed along the first direction and extend along a second direction orthogonal to the first direction, and a flat portion that is disposed between projections adjacent to each other among the plurality of projections and extends along the second direction.

The projections include a first projection and a second projection along the second direction, the first projection and the second projection having mutually different heights, the second projection having a higher height than the height of the first projection.

Brief Description of the Drawings

[0006] [Fig. 1] Fig. 1 is a perspective view of a disposable diaper according to first to sixth embodiments of the present invention.

[Fig. 2] Fig. 2 is a schematic exploded perspective view of an unfolded state of the disposable diaper according to the first embodiment.

[Fig. 3] Fig. 3 is a plan view showing the unfolded state of the disposable diaper according to the first embodiment and is a view seen from the inside.

[Fig. 4] Fig. 4 is a plan view showing an unfolded state of an exterior member of the disposable diaper according to the first embodiment and is a view for describing a pattern of a bonding layer in the exterior member.

[Fig. 5] Fig. 5 is a developed schematic perspective view of a region surrounded by an ellipse V of Fig. 3, showing a natural state where extension of the exterior member is released and showing a state where a folded-back portion is unfolded.

[Fig. 6] Fig. 6 is a cross-sectional view taken along the line VI-VI of Fig. 3.

[Fig. 7] (A) is a plan view showing in an enlarged manner a first sheet 11 in a region surrounded by an ellipse VIIA of Fig. 4 and schematically showing the structure of the first sheet 11, and (B) is a cross-sectional view taken along the line VIIB-VIIB of (A) of Fig. 7.

[Fig. 8] Fig. 8 is a plan view showing an unfolded state of a disposable diaper of a second embodiment and is a view seen from the inside.

[Fig. 9] Fig. 9 is a plan view showing an unfolded state of an exterior member of a disposable diaper of a third embodiment and is a view for describing a pattern of a bonding layer in the exterior member.

[Fig. 10] Fig. 10 is a plan view showing an unfolded state of an exterior member of a disposable diaper of a fourth embodiment and is a view for describing a pattern of bonding layer in the exterior member. a [Fig. 11] Fig. 11 is a plan view showing an unfolded state of an exterior member of a disposable diaper of a fifth embodiment and is a view for describing a pattern of bonding layer in the exterior member. a [Fig. 12] Fig. 12 is a plan view showing an unfolded state of an exterior member of a disposable diaper of a sixth embodiment and is a view for describing a pattern of bonding layer in the exterior member. a [Fig. 13] Fig. 13 is an enlarged plan view of another first sheet constituting an exterior member of a seventh embodiment and is a view schematically showing a structure of the first sheet.

[Fig. 14] Fig. 14 is a perspective view schematically showing a natural state of a stretchable sheet according to an eighth embodiment of the present invention.

[Fig. 15] (A) is a cross-sectional view schematically showing a state where the stretchable sheet of Fig. 14 is cut along the line IIA-IIA along a stretching direction, and (B) is a cross-sectional view schematically showing a state where the stretchable sheet of Fig. 14 is cut along the line IIB-IIB. [Fig. 16] Fig. 16 is a perspective view schematically showing a state where the stretchable sheet of Fig. 14 is made straight without extending elastic filaments such that the undulations of the corrugated shape of the elastic filaments are made straight, and a boundary surface between a first non-woven fabric and a second non-woven fabric is spread in a planar shape.

[Fig. 17] Fig. 17 is a schematic plan view of the stretchable sheet of Fig. 14 and is a plan view showing a state where the boundary surface between the first non-woven fabric and the second non-woven fabric is spread in a planar shape as in Fig. 16.

[Fig. 18] Fig. 18 is a partially enlarged cross-sectional view schematically showing the vicinity of a projection in a natural state and in an extended state of the stretchable sheet of Fig. 16, in which (A) shows a natural state, and (B) shows a state where the stretchable sheet is extended in a stretching direction (Y-axis direction).

[Fig. 19] Fig. 19 is a schematic plan view showing a state where the stretchable sheet of Fig. 14 is extended in the stretching direction.

[Fig. 20] (A) is a cross-sectional view schematically showing a state corresponding to Fig. 16, and (B) is a cross-sectional view corresponding to Fig. 14 and schematically showing a state where the corrugated shape of the elastic filaments of the stretchable sheet and of the boundary surface between the first non-woven fabric and the second non-woven fabric is maintained.

[Fig. 21] Fig. 21 is a schematic enlarged plan view of a non-woven fabric, showing positions of thermally-fused portions constituting part of the stretchable sheet of Fig. 14. [Fig. 22] Fig. 22 is a cross-sectional view schematically showing a stretching apparatus of one embodiment, which is used when the stretchable sheet is produced.

[Fig. 23] (A) is a perspective view of a toothed stretching roll used in the stretching apparatus of Fig. 22, and (B) is a perspective view of a tooth provided to the toothed stretching roll.

[Fig. 24] Fig. 24 is a view schematically showing a state where projections of the stretchable sheet are formed by roll stretching, in which each view of (A), (B), and (C) shows, in its upper part, a partially enlarged view of the stretching apparatus of Fig. 22 at the time of roll stretching and shows, in its lower part, a cross-sectional view of a laminate or a stretchable sheet at the time of processing shown in the upper part in a state where it is extended in a planar shape without extending the elastic filaments.

[Fig. 25] Fig. 25 is a perspective view of a disposable diaper using the stretchable sheet.

[Fig. 26] Fig. 26 is a schematic exploded perspective view of an unfolded state of the disposable diaper of Fig. 25.

[Fig. 27] Fig. 27 is a plan view showing an unfolded state of an exterior member of the disposable diaper of Fig. 25.

[Fig. 28] Fig. 28 is a partially enlarged cross-sectional view of a stretchable sheet according to a ninth embodiment and is a view schematically showing a state corresponding to Fig. 16.

[Fig. 29] Fig. 29 is a schematic exploded perspective view of an unfolded state of a disposable diaper according to another embodiment.

Detailed Description of the Invention

[0007] In pant-type absorbent articles, one presenting an appearance and the sense of touch like pants as underwear is expected. The present invention has an object related to a pant-type absorbent article presenting an appearance and the sense of touch like pants as underwear (fabric) while maintaining fitting property. Further, the present invention has an object related to a stretchable sheet suitable for a pant-type absorbent article or the like for which fitting property around a trunk is expected.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The drawings show the X-axis, the Y-axis, and the Z-axis orthogonal to one another as necessary.

[0009] <First Embodiment> [Overall Configuration of Disposable Diaper] A disposable diaper 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. The disposable diaper 1 is a pant-type absorbent article for catching the excreta of a baby or infant being a wearer without leaking it.

The disposable diaper 1 includes an exterior member 8 and an absorbent member 9. The exterior member 8 constitutes the exterior of the disposable diaper 1. The absorbent member 9 is held inside of the exterior member 8. In other words, the exterior member 8 is disposed on the surface side on the outside of the absorbent member 9, which faces to the side opposite to the skin side of a wearer when the disposable diaper is worn. Hereinafter, the inside in each configuration indicates a side, of the disposable diaper, positioned on the skin side of a wearer when the disposable diaper is worn, and the outside indicates the opposite side of the skin side of the wearer.

[0010] The exterior member 8 includes a waist portion 16 and a crotch portion 17 that are continuously formed. The waist portion 16 forms a waist opening 7 and is disposed around the trunk of the wearer. The waist portion 16 includes a stretchable sheet that is stretchable over the circumferential direction of the trunk so as to be fitted around the trunk of the wearer. The crotch portion 17 is positioned on the lower side of the waist portion 16 in Fig. 1 and disposed in the crotch of the wearer.

[0011] The waist portion 16 includes an abdominal portion 16a disposed on the front side when the disposable diaper is worn, and a dorsal portion 16b disposed on the rear side.

The abdominal portion 16a and the dorsal portion 16b are joined in side seal portions 18 provided to both ends in a width direction orthogonal to a front-back direction by, for example, heat sealing or ultrasonic sealing. Thus, the waist portion 16 has a tubular shape and forms the waist opening 7 between the abdominal portion 16a and the dorsal portion 16b.

[0012] The crotch portion 17 is positioned between the abdominal portion 16a and the dorsal portion 16b. The crotch portion 17 connects the abdominal portion 16a and the dorsal portion 16b to each other so as to form a pair of leg openings 14, into which the legs of the wearer are inserted, on both sides of the crotch portion 17 in the width direction. The crotch portion 17 includes leg gathers 19 that are disposed along the leg openings 14 and include rubber threads 19a. The leg gathers 19 fit the legs of the wearer, which are inserted into the leg openings 14, by extension and contraction of the rubber threads 19a.

[0013] The disposable diaper 1 and the exterior member 8 shown in Figs. 2 to 4 are in a state where the side seal portions 18 are torn off to separate the abdominal portion 16a and the dorsal portion 16b from each other, and the exterior member 8 and the absorbent member 9 are further extended and spread along the X-Y plane from the state shown in Fig. 1.

Fig. 3 shows that a second sheet 12 is positioned on the near side and a first sheet 11 is positioned on the far side, the second sheet 12 and the first sheet 11 constituting the exterior member 8. For the purpose of convenience, Fig. 3 shows the absorbent member 9 in a dotted line. In Fig. 3, in order to show the laminated state of the exterior member 8, the lower right-hand corner portion of the dorsal oortion 16b of the second sheet 12 and a bonding layer 13 positioned to correspond thereto are cut out to show the first sheet 11 positioned on the far side in the figure. It should be noted that the same holds true for Fig. 8 to be described later.

Fig. 4 shows that the first sheet 11 is positioned on the near side and the second sheet 12 is positioned on the far side, the first sheet 11 and the second sheet 12 constituting the exterior member 8. For the purpose of convenience, Fig. 4 shows the bonding layer 13 in a solid line. In Fig. 4, in order to show the laminated state of the exterior member 8, the lower right-hand corner portion of the first sheet 11 and the bonding layer 13 positioned to correspond thereto are cut out to show the second sheet 12 positioned on the far side in the figure. It should be noted that the same holds true for Figs. 9 to 12 to be described later.

[0014] As shown in Fig. 2, the exterior member 8 includes a composite sheet 10 in which the first sheet 11 and the second sheet 12 are attached to each other with the bonding layer 13. The first sheet 11 constituting the exterior member 8 is folded inward at opening circumferential edges 15 of the waist opening 7 of the disposable diaper 1. Fig. 3 shows a state where a folded-back portion 20 of the first sheet 11 is folded inward, and Fig. 4 shows a state where the folded-back portion 20 is unfolded.

[0015] In the disposable diaper 1 shown in Figs. 2 and 3 and the exterior member 8 shown in Fig. 4, the X-axis direction corresponds to the front-back direction, the Y-axis direction corresponds to the width direction, and the Z-axis direction corresponds to the thickness direction. The circumferential direction of the trunk in the abdominal portion 16a and the dorsal portion 16b of the waist portion 16 in Fig. 1 corresponds to the width direction Y in Figs. 3 and 4.

Hereinafter, in the description for the waist portion 16, an up-down direction will be described in some cases. The up-down direction corresponds to the up-down direction of the disposable diaper 1 when a wearer standing up wears the disposable diaper 1. The front-back direction and the up-down direction are the same direction. Hereinafter, the disposable diaper 1 will be described in the form shown in Figs. 2 to 4.

[0016] As shown in Figs. 1 to 3, the absorbent member 9 is configured to be capable of catching excreta and also absorbing liquid included in the excreta. The absorbent member 9 is formed into a belt-like shape and is disposed in a wide range in the exterior member 8 from the crotch portion 17 to the abdominal portion 16a and the dorsal portion 16b of the waist portion 16. Thus, in the disposable diaper 1, the absorbent member 9 covers the wide range of the crotch of the wearer, and thus the excreta is less likely to leak even when the wearer moves.

Further, the absorbent member 9 absorbs liquid mainly in a region for catching excreta in the crotch portion 17. The liquid absorbed in the absorbent member 9 does not remain in that region and is soaked up toward the waist portion 16. In other words, the absorbent member 9 can retain the liquid in the wide range over the crotch portion 17 and the waist portion 16. Thus, the disposable diaper 1 allows a sufficient amount of liquid to be absorbed by the absorbent member 9.

[0017] As shown in Fig. 2, the exterior member 8 includes the composite sheet 10 that is a stretchable sheet. The composite sheet 10 includes the first sheet 11 made of a stretchable non-woven fabric including a non-woven fabric layer containing an elastic resin, the second sheet 12 made of a non-stretchable non-woven fabric facing the first sheet 11, and the bonding layer 13 that bonds the first sheet 11 and the second sheet 12 to each other. The first sheet is a stretchable sheet, and the second sheet is a non-stretchable sheet. Here, the stretchable non-woven fabric means a fabric having 70% or more of a recovery rate (extension recovery rate) when the fabric is extended by 100% in at least the same direction as a contraction direction. Further, the degree of elongation of the stretchable non-woven fabric (first sheet) used in this embodiment is preferably 100G or more, and more preferably 150% or more. In this embodiment, the second sheet 12 is provided to face the inside of the first sheet 11, and the first sheet 11 is positioned on the side of an outer surface 8a of the exterior member 8. Each of the sheets 11 and 12 and the bonding layer 13 constituting the exterior member 8 will be described later in detail.

[0018] The waist portion 16 of the exterior member 8 has stretch property in the circumferential direction of the trunk. As shown in Fig. 3, in the waist portion 16 of the exterior member 8 that needs stretch property in the circumferential direction of the trunk, the abdominal portion 16a (dorsal portion 16b) includes a first region 31a (first region 31b), a second region 32a (second region 32b), and a third region 33a (third region 33b), which have mutually different contraction stresses in the circumferential direction of the trunk. The first region 31a (first region 31b), the second region 32a (second region 32b), and the third region 33a (third region 33b) have an equal dimension in the circumferential direction of the trunk in a natural state (stress release state). Hereinafter, when the sheet is extended to 185') of the length in a natural state in the circumferential direction and then contracted to 140 of the length, a tensile load (cN) per unit length (1 mm) is assumed to be a contraction stress of the sheet.

[0019] The first region 31 (second region 32, third region 33) includes the first region 31a of the abdominal portion (second region 32a of abdominal portion, third region 33a of abdominal portion) and the first region 31b of the dorsal portion (second region 32b of dorsal portion, third region 33b of dorsal portion), and unless otherwise distinguished therebetween, both of them are referred to as the first region 31 (second region 32, third region 33).

In Figs. 3 and 4, the stretchable regions are shown in a dot pattern, and the degree of magnitude of the contraction stress in each region is expressed by the density of the dot pattern. As the contraction stress increases, the density of the dot pattern increases, and as the contraction stress decreases, the density of the dot pattern decreases.

Hereinafter, the same holds true for the dot patterns of the figures to be used for description of other embodiments to be described later.

[0020] The first region 31, the second region 32, and the third region 33 have mutually different contraction stresses.

Specifically, in this embodiment, the contraction stress is the highest in the first region 31, the second highest in the third region 33, and the lowest in the second region 32. In other words, the first to third regions 31 to 33 are configured to have different forces to return to the original state by contraction (contraction stress) in each region when the first to third regions 31 to 33 are extended at the same extension rate. Thus, when the waist portion 16 is extended at the same extension rate, different tightening pressures for each of the regions are to be applied to the wearer. In this embodiment, the second region 32 and the third region 33 are positioned on the upper side of the first region 31 in the up-down direction orthogonal to the circumferential direction of the trunk. In other words, the lower side of the waist portion 16 is configured to have a higher contraction stress than that of the upper side of the waist portion 16.

[0021] The third region 33 is positioned at the opening circumferential edge 15 that is an edge portion of the exterior member 8 on the upper side. The composite sheet 10 constituting the exterior member 8 is folded inward and downward in the up-down direction, thus forming the third region 33. The length of the third region 33 in the up-down direction is 1/2 or less, in this embodiment, approximately 1/3, of the length of the second region 32 in the up-down direction.

Specifically, as shown in Fig. 2, in the composite sheet 10, the first sheet 11 has portions extended from the second sheet 12 at both ends in the front-back direction, and those extended portions are to be the folded-back portions 20. The folded-back portions 20 are folded back with the positions of both end edges of the second sheet 12 in the front-back direction being as folded-back positions. The folded-back positions correspond to the positions of the opening circumferential edges 15 when the disposable diaper 1 is obtained.

[0022] [Detailed Structure of Exterior Member] Hereinafter, each configuration of the exterior member 8 will be described in detail with reference to Figs. 2 to 7.

While Figs. 5 and 6 each show a partial view of the dorsal portion 16b, the abdominal portion 16a also has a similar configuration.

[0023] (First Sheet) The first sheet 11 is a single-layer stretchable non-woven fabric continuously formed from the abdominal portion 16a to the dorsal portion 16b through the crotch portion 17, that is, a stretchable non-woven fabric including one layer.

As shown in Figs. 2, 4, and 5, the first sheet 11 includes extended portions that are extended from the second sheet 12 at both ends in the front-back direction. The extended portions are the folded-back portions 20 folded inward. Folded portions obtained by folding back the folded-back portions 20 are to be the third regions 33. As shown in Fig. 6, in the third region 33, two first sheets 11, one second sheet 12, and two bonding layers 13 are laminated, thus providing a structure in which the first sheet 11 is doubled.

[0024] As shown in Fig. 4, the first sheet 11 in the waist portion 16 of the exterior member 8 includes high contraction stress regions P1 and low contraction stress regions P2, which have different contraction stresses in the front-back direction, in an unfolded state where the folded-back portions 20 are unfolded. The high contraction stress region P1 and the low contraction stress region P2 are different from each other in contraction stress. In this embodiment, the contraction stress of the low contraction stress region P2 is lower than the contraction stress of the high contraction stress region P1. Further, a width dimension of the low contraction stress region P2 is equal to a width dimension of the high contraction stress region P1.

The high contraction stress region P1 corresponds to the first region 31.

The low contraction stress region P2 corresponds to the second region 32 and the third region 33. In the second region 32, the low contraction stress region P2 of the first sheet 11 is positioned as a single layer, whereas in the third region 33, the low contraction stress region P2 of the first sheet 11 is positioned as a doubled layer. Thus, the third region 33 has a higher contraction stress than the contraction stress of the second region 32.

In such a manner, the first sheet 11 of the exterior member 8 in this embodiment includes the high contraction stress regions P1 and the low contraction stress regions P2 that have mutually different contraction stresses in the front-back direction, in a state before assembled to be the exterior member 8.

[0025] As shown in Fig. 7, the first sheet 11 is a stretchable non-woven fabric including a plurality of elastic filaments 42 and a non-woven fabric layer 41 containing the elastic filaments 42. The first sheet 11 includes the nonwoven fabric layer 41 extending along the X-Y plane, and the elastic filaments 42 serving as elastic resin contained in the non-woven fabric layer 41.

The non-woven fabric layer 41 is formed of a non-woven fabric including a fiber having low elasticity. The nonwoven fabric forming the non-woven fabric layer 41 is not limited to a specific kind and is selectable from, for example, an air-through non-woven fabric, a heat roll non-woven fabric, a spun lace non-woven fabric, a spun-bonded non-woven fabric, and a melt-blown non-woven fabric. Further, the fiber constituting the non-woven fabric layer 41 is not limited to a specific kind and is selectable from, for example, chemical fibers of polyethylene, polypropylene, polyester, polyamide, and the like. Moreover, the non-woven fabric layer 41 may be made of a composite fiber including a plurality of kinds of chemical fibers. In addition, the fiber constituting the non-woven fabric layer 41 may contain natural fibers such as cotton and silk.

The elastic filaments 42 are thread-like elastic members that extend along the Y-axis direction. The elastic filaments 42 are arranged at regular intervals in the X-axis direction in the waist portion 16. The elastic filaments 42 can be formed of, for example, an elastic material such as thermoplastic elastomer or rubber. In particular, the elastic filaments 42 are preferably formed of thermoplastic elastomer, which is easily fused to the fiber constituting the non-woven fabric layer 41. For the thermoplastic elastomer to form the elastic filaments 42, for example, styrene elastomer, olefinic elastomer, polyester elastomer, polyurethane elastomer, or the like can be used. Further, the elastic filaments 42 can be formed in combination of a plurality of kinds of thermoplastic elastomer. Moreover, the elastic filaments 42 may be a core-sheath type or side-byside type composite fiber.

[0026] Further, in the first sheet 11, stretchable portions 11a and connection portions llb that extend in the X-axis direction are alternately arranged along the Y-axis direction. In the first sheet 11, a basis weight of the nonwoven fabric layer 41 in the stretchable portion lla is lower than a basis weight of the non-woven fabric layer 41 in the connection portion 11b. Thus, the stretchable portion 11a is easier to deform in the Y-axis direction than the connection portion 11b. In the non-woven fabric layer 41, the connection portion 11b that is difficult to deform ensures the strength.

[0027] In the extended state of the first sheet 11 in the waist portion 16, when a force to extend in the Y-axis direction is applied, the stretchable portions 11a mainly extend in the Y-axis direction. In this embodiment, in the extended first sheet 11, the connection portions 11b and the stretchable portions lla each extend, but the stretchable portions 11a more largely extend than the connection portions 11b. It should be noted that the connection portions 11b do not need to be substantially extended, and it may suffice that the stretchable portions 11a have a lager degree of extension than that of the connection portions 11b. Meanwhile, when the force to extend in the Y-axis direction is released from the extended state, the first sheet 11 in the waist portion 16 is contracted in the Y-axis direction due to the elastic force of the elastic filaments 42. The contracted first sheet 11 has a smaller dimension of the stretchable portion 11a in the Y-axis direction than that of the extended first sheet 11. As described above, the first sheet 11 is a stretchable non-woven fabric that is stretchable in the Y-axis direction.

[0028] The elastic filaments 42 are made of an elastic fiber and arranged at regular intervals in the X-axis direction. In this embodiment, elastic filaments 42a made of relatively thick elastic fibers are disposed in the first region 31, and elastic filaments 42b made of relatively thin elastic fibers are disposed in the second region 32. This can cause the contraction stress to differ between the first region 31 and the second region 32.

[0029] In such a manner, in the composite sheet 10, the first sheet 11 is stretchable by itself due to the elastic force of the elastic filaments 42. Thus, in the composite sheet 10, the waist portion 16 of the exterior member 8 can be extended and contracted in the circumferential direction of the trunk in Fig. 1 by using the stretch property of the first sheet 11. Therefore, the composite sheet 10 can have a configuration including no elastic member such as a rubber thread between the first sheet 11 and the second sheet 12.

[0030] The first sheet 11 can be produced by an arbitrary production method. For example, the first sheet 11 can be produced using the elastic filaments 42 and two non-woven fabrics. In this production method, first, the elastic filaments 42, which are made by melt spinning, are sandwiched between the two non-woven fabrics to form a laminate. Thus, the non-woven fabrics and the elastic filaments 42 are fused.

In the first sheet 11 at this stage, a basis weight of the non-woven fabric layer 41 is constant, and the stretchable portions lla and the connection portions llb are not formed. In order to form the stretchable portions lla and the connection portions llb in the first sheet 11, for example, stretching for elongation in the Y-axis direction can be performed on only the stretchable portions 11a. Thus, only the basis weight of the stretchable portions lla can be reduced while maintaining the basis weight of the connection portions 11b.

[0031] An arbitrary method can be used for the stretching for forming the stretchable portions lla and the connection portions 11b in the first sheet 11. For example, roll stretching using two toothed rolls meshed with each other can be used. In this roll stretching, the first sheet 11 is bitten between the rotating toothed rolls and is thus intermittently stretched to alternately form the stretchable portions lla and the connection portions 11b. The laminate formed by sandwiching the elastic filaments 42 between the two non-woven fabrics is subjected to the roll stretching to stretch the two non-woven fabrics, thus forming the non-woven fabric layer 41.

In such a manner, the non-woven fabrics and the elastic filaments 42 sandwiched between the non-woven fabrics are fused to constitute the first sheet 11, and thus the elastic filaments 42 are not exposed from the surface of the nonwoven fabric layer 41 and are contained in the non-woven fabric layer 41. The first sheet 11 has a single-layer stretchable configuration.

[0032] In this production method, the first sheet 11 can be produced without using adhesives. Thus, in the first sheet 11, the touch feeling of the non-woven fabric layer 41 is not impaired by adhesives. Further, in the first sheet 11, the touch feeling of the non-woven fabric layer 41 is not also impaired by the elastic filaments 42 contained in the non-woven fabric layer 41. Thus, in the first sheet 11, the original soft touch feeling of the non-woven fabric layer 41 is obtained as it is.

[0033] Further, the elastic resin contained in the non-woven fabric layer 41 of the first sheet 11 only needs to have a configuration with elasticity at least in the Y-axis direction and is not limited to the configuration using the elastic filaments 42.

For example, the elastic resin contained in the non-woven fabric layer of the first sheet 11 may be elastic fibers made of, for example, short fibers. While the elastic filaments are arranged such that the elastic fibers extend in one direction without intersecting with each other, in the case of using elastic fibers made of short fibers, such elastic fibers may be disposed at random or may be disposed to be oriented in one arbitrary direction. Also in those configurations, the non-woven fabric layer 41 is capable of being fused to the elastic resin, and thus the first sheet 11 can be produced without using adhesives.

[0034] (Bonding Layer) As shown in Fig. 2, the bonding layer 13 includes a plurality of bonding portions 21 disposed between the first sheet 11 and the second sheet 12. As shown in Fig. 5, the bonding layer 13 is disposed so as to form a sequence of patterns over the first region 31a (first region 31b) and the second region 32a (second region 32b) of the abdominal portion 16a (dorsal portion 16b).

[0035] In this embodiment, the bonding layer 13 is provided in a sequence of patterns over the entire region of the abdominal portion 16a and the entire region of the dorsal portion 16b, which include the stretchable regions. The bonding layer 13 includes the plurality of bonding portions 21 disposed at intervals therebetween in the circumferential direction of the trunk. The bonding portions 21 extend over the first region 31a (first region 31b) and the second region 32a (second region 32b) of the abdominal portion 16a (dorsal portion 16b). The plurality of bonding portions 21 extend continuously in a long thin belt-like shape with an equal width along one direction, in this embodiment, along the up-down direction, and are intermittently arranged at regular intervals in the circumferential direction of the trunk.

It should be noted that this embodiment has described the example in which the bonding layer 13 is provided in the waist portion 16 including the stretchable regions, but the bonding layer 13 may also be provided in the crotch portion 17 continuously with the waist portion 16 in a sequence of patterns.

[0036] The bonding layer 13 is typically formed of an adhesive. For the method of forming the bonding layer, for example, various printing methods, various transfer methods, and the like are available. For the printing methods, for example, gravure printing, letterpress printing, offset printing, and the like are available. For the transfer methods, for example, roll transfer, thermal transfer, and the like are available.

For the adhesive to form the bonding layer 13, a hot-melt adhesive is used. It should be noted that the bonding layer 13 can be formed of various adhesives such as a thermoplastic adhesive and a reactive adhesive, other than the hot-melt adhesive. Further, the bonding layer 13 can also be formed of various bonding members other than adhesives. Examples of such bonding members include a sheet-like member having viscosity on both surfaces, such as a double-sided tape.

[0037] (Second Sheet) The second sheet 12, which is made of a non-stretchable non-woven fabric and constitutes part of the composite sheet 10, can be formed of an arbitrary non-stretchable member that is difficult to extend and contract in the Y-axis direction.

For the non-stretchable member constituting the second sheet 12, for example, a non-woven fabric, a woven fabric, paper, and the like can be used. As an example, the second sheet 12 can be formed of a non-woven fabric using a fiber similar to that of the non-woven fabric layer 41 of the first sheet 11 in order to obtain a touch feeling like the first sheet 11.

[0038] As shown in Fig. 2, the outer shape of the second sheet 12 is almost the same as the shape of the first sheet 11, which excludes the folded-back portions 20 from the extended first sheet 11. The bonding layer 13 extends in the up-down direction and is intermittently arranged in the circumferential direction of the trunk. Thus, after the extended first sheet 11 and the second sheet 12 are attached to each other via the bonding layer 13, the second sheet 12 forms a plurality of raised portions 35 that are raised to the side opposite to the first sheet 11, as shown in Fig. 5, in a natural state of the exterior member 8 in which the extended state of the first sheet 11 is released. Each of the raised portions 35 is formed between adjacent rows of the bonding portions 21 by the second sheet 12 bulging in a direction away from the first sheet 11.

[0039] In this embodiment, as shown in Fig. 4, since the plurality of bonding portions 21 constituting the bonding layer 13 are intermittently arranged at regular intervals in the circumferential direction of the trunk, the raised portions 35 each extend along the up-down direction while having an equal width and are arranged at regular intervals in the circumferential direction, to form folds with a uniform pattern in the in-plane direction on the inside of the waist portion 16 of the exterior member 8. In such a manner, in the disposable diaper 1, the plurality of raised portions 35 of the second sheet 12 form a sequence of patterns in a natural state where extension is not applied. Here, the sequence of patterns refers to a state where a pattern formed by the plurality of raised portions 35 formed in the first region 31 is the same as a pattern formed by the plurality of raised portions 35 formed in the second region 32, and the flow of the pattern formed in each region continues also in the vicinity of the boundary between the first region 31 and the second region 32 without being disconnected.

[0040] In this embodiment, since the second sheet 12 is disposed inside of the disposable diaper 1, the raised portions 35 are formed inside of the disposable diaper 1. Meanwhile, since the first sheet 11 is positioned outside of the disposable diaper 1, the outer surface of the disposable diaper 1 includes no raised portions.

[0041] [Method of Producing Exterior Member] The exterior member 100 is formed by disposing the bonding layer 13 on the first sheet 11 extended at a constant extension rate and attaching the second sheet 12 thereto. Here, attaching at a constant extension rate refers to attaching the second sheet 12 in a state where the high contraction stress regions P1 and the low contraction stress regions P2 of the first sheet 11 are extended at the same extension rate.

[0042] Specifically, in the state where the first sheet 11 is extended at a constant extension rate, as shown in Fig. 4, the bonding layer 13 is disposed on the entire surface of the region corresponding to the waist portion 16 including the folded-back portions 20 as well. The second sheet 12 is superimposed on the first sheet 11 on which the bonding layer 13 is disposed, and both of them are bonded to each other by the bonding layer 13. In this state, the folded-back portions 20 are extended from the regions in which the first sheet 11 and the second sheet 12 overlap each other, and the bonding layer 13 is disposed on the folded-back portions 20.

After the second sheet 12 is attached to the first sheet 11, the extended folded-back portions 20 are folded toward the inside of the exterior member 8, and the folded-back portions 20 and the second sheet 12 are attached to each other. Thus, the exterior member 8 is formed.

Next, after the absorbent member 9 is bonded and fixed to the inside of the extended exterior member 8, the dorsal portion 16b and the abdominal portion 16a are superimposed on each other while maintaining the extended state, and corresponding side edge portions are joined to from the side seal portions 18. Thus, a pull-on disposable diaper 1 is produced.

In the produced disposable diaper 1, the raised portions 35 having a sequence of patterns are formed inside in a natural state where no tension is applied from the outside.

[0043] [Method of Measuring Extension Recovery Rate and Degree of Elongation] The extension recovery rate and the degree of elongation of the stretchable non-woven fabric used for the first sheet 11 can be measured as follows.

(Method of Measuring Extension Recovery Rate) A sample piece of a stretchable non-woven fabric having a length of 50 mm and a width of 25 mm is prepared. After the sample piece is fixed at a chuck interval LO and extended to a length of L2 (L2 = L0x2) at 100% extension at a rate of 300 ram/min by using a Tensilon tensile tester ("Autograph AG-X" manufactured by Shimadzu Corporation), when the sample piece starts to recover at a rate similar to a tensile rate and a tensile load reaches zero, the length of the sample piece is assumed as a length Ll after extension recovery. The extension recovery rate at 100% extension is calculated from the following expression.

Extension recovery rate at 100% extension (%) = {(52-L1)/(L2-L0)1x100 (Method of Measuring Degree of Elongation) A sample piece with the same dimension as the dimension of the sample piece used in the method of measuring an extension recovery rate is extended under conditions similar to those in the method of measuring an extension recovery rate, and the degree of elongation obtained when the sample piece is broken is assumed as the degree of elongation.

[0044] [Method of Measuring Dimensions of First Region and Second Region in Circumferential Direction] The disposable diaper 1 is placed on a desk in a natural state, and a width in the circumferential direction between the side seal portion 18 and a region sandwiched by extended lines of a pair of both side edge portions of the absorbent member 9 that define the width direction of the absorbent member 9 is measured. Thus, a dimension relationship in the circumferential direction between the first region 31 and the second region 32 of the exterior member 8 in a natural state can be found.

In this embodiment, the first region and the second region have an equal dimension in the circumferential direction in a natural state. In other words, the first region and the second region have an equal distance in the circumferential direction between the side seal portion 18 and the extended line of the side edge portion of the absorbent member 9. Here, being equal means that a value of the distance in one region is within the range of 95% to 105' of the distance in the other region.

[0045] [Contraction Stress Value, Dimension in Each Region, and Method of Measuring Contraction Stress Value] (Contraction Stress Value and Dimension in Each Region) A preferable contraction stress value in the exterior member 8 is as follows.

The contraction stress of the first region 31 is preferably 1.4 cN/mm or more and more preferably 2 cN/mm or more, and further, preferably 5 cN/mm or less. The contraction stress of the first region 31 is preferably 1.4 cN/mm or more and 5 cN/mm or less, and more preferably 2 cN/mm or more and 5 cN/mm or less.

The contraction stress of the second region 32 is preferably 0.1 cN/mm or more and more preferably 0.5 cN/mm or more, and further, preferably 3 cN/mm or less and more preferably 2.5 cN/mm or less. The contraction stress of the second region 32 is preferably 0.1 cN/mm or more and 3 cN/mm or less, and more preferably 0.5 cN/mm or more and 2.5 cN/mm or less.

The contraction stress of the third region 33 is preferably 1.4 cN/mm or more and more preferably 1.5 cN/mm or more, and further, preferably 4 cN/mm or less and more preferably 3.5 cN/mm or less. The contraction stress of the third region 33 is preferably 1.4 cN/mm or more and 4 cN/mm or less, and more preferably 1.5 cN/mm or more and 3.5 cN/mm or less.

It should be noted that those numerical values are appropriately set in accordance with the size of a disposable diaper corresponding to the body size of a wearer.

[0046] The contraction stress of the first region 31 is preferably 1.2 times or more and more preferably 1.4 times or more the contraction stress of the second region 32, and further, preferably 3 times or less and more preferably 2.5 times or less the contraction stress of the second region 32.

The contraction stress of the first region 31 is preferably 1.2 times or more and 3 times or less, and more preferably 1.4 times or more and 2.5 times or less the contraction stress of the second region 32.

The contraction stress of the first region 31 is preferably 1.1 times or more and more preferably 1.5 times or more the contraction stress of the third region 33, and further, preferably 2.5 times or less and more preferably 2 times or less the contraction stress of the third region 33. The contraction stress of the first region 31 is preferably 1.1 times or more and 2.5 times or less, and more oreferably 1.5 times or more and 2 times or less the contraction stress of the third region 33.

[0047] Further, the dimension in each region is preferably set as follows.

The length of the first region 31 in the up-down direction is preferably 1.0 times or more and more preferably 1.2 times or more the length of the second region 32, and further, preferably 2 times or less and more preferably 1.8 times or less the length of the second region 32. The length of the first region 31 in the up-down direction is preferably 1.0 times or more and 2 times or less, and more preferably 1.2 times or more and 1.8 times or less the length of the second region 32.

The length of the third region 33 in the up-down direction is preferably 1/2 or less of the length of the second region 32.

The length of the third region 33 in the up-down direction is preferably 0.5 cm or more, and further, preferably 5 cm or less, more preferably 3 cm or less, and even more preferably 1.5 cm or less. The length of the third region 33 in the up-down direction is preferably 0.5 cm or more and 5 cm or less, more preferably 0.5 cm or more and 3 cm or less, and even more preferably 0.5 to 1.5 cm or less. Specific dimensions differ depending on the size of the disposable diaper 1.

[0048] The contraction stresses of the first to third regions 31 to 33 of the exterior member 8 can be measured as follows.

(Method of Creating Samples for Measuring Contraction Stresses of Exterior member) The side seal portions 18 of the disposable diaper 1 are peeled, and the exterior member 8 is extended at the same ratio in each of the first to third regions 31 to 33 of the exterior member 8 to be unfolded and spread on the plane. Each of the abdominal portion 16a and the dorsal portion 16b is cut along straight lines parallel to the width direction and further cut along straight lines parallel to the front-back direction, to cut out rectangular samples from the respective regions of the first to third regions 31 to 33.

The samples are cut out of, in plan view, a region of the exterior member 8 other than the region facing the absorbent member 9 and a region of the exterior member 8 outside of the region sandwiched by the extended lines of the pair of both side edge portions of the absorbent member 9 that define the width direction of the absorbent member 9. The samples are cut out to have a belt-like shape and a size of 70 mm along the width direction and 50 mm along the front-back direction in a stress release state (natural state) after cutting, thus creating the samples each having a width of 50 mm and a length of 70 mm. It should be noted that if it is difficult to form a sample having a length of 70 mm in the width direction of the diaper, the length is appropriately changed.

(Measurement Method) Both sides of the cut-out sample of each region in the length direction (corresponding to the width direction of the disposable diaper) are fixed between a pair of chucks of the Tensilon tensile tester described above. To fix the sample, a portion with a 10-mm width from the end edge in each of both the ends of the sample in the length direction is nipped with the chuck to be fixed. A chuck interval is set to 50 mm, and the sample is fixed in a natural state (naturally contracted state without application of external force). It should be noted that the chuck interval is appropriately adjusted in accordance with the length of the sample piece.

The sample is then extended at 300 mm/min in the same direction as the width direction of the diaper (length direction of sample). After the sample is extended until the length of the sample (distance between chucks) is 185% of the length in a natural state, when the sample is contracted to the length of 140%, a tensile load (cN) per unit length (1 mm) in the width direction is assumed as a contraction stress.

It should be noted that setting 140% as an index is for reproducing the extended state of the sample when the pull-on disposable diaper 1 is worn.

[0049] [Thickness of Elastic Fiber] The thickness of the elastic fiber of the elastic filaments 42a used for the first region 31 is preferably 20 pm or more and more preferably 40 pm or more, and further, preferably 400 pm or less and more preferably 300 pm or less. The above-mentioned thickness is preferably 20 pm or more and 400 pm or less, and more preferably 40 pm or more and 300 pm or less.

The thickness of the elastic fiber of the elastic filaments 42b used for the second region 32 is preferably 10 pm or more and more preferably 20 pm or more, and further, preferably 300 pm or less and more preferably 250 pm or less.

The above-mentioned thickness is preferably 10 pm or more and 300 um or less, and more preferably 20 pm or more and 250 pm or less.

The thickness of the elastic fiber used for the first region 31 is preferably 1.2 or more and more preferably 1.5 times or more the thickness of the elastic fiber used for the second region 32, and further, preferably 3 times or less and more preferably 2.5 times or less the thickness of the elastic fiber used for the second region 32. The above-mentioned thickness is preferably 1.2 times or more and 3 times or less, and more preferably 1.5 times or more and 2.5 times or less the thickness of the elastic fiber used for the second region 32.

It should be noted that the thickness of the elastic fiber corresponds to a fiber diameter of the elastic fiber.

[0050] [Function and Effect of This Embodiment] In the disposable diaper 1 of this embodiment, the first sheet 11 for providing stretch property to the composite sheet 10 including the abdominal portion 16a and the dorsal portion 16b is a single seamless member and has a configuration including the regions having mutually different contraction stresses in the up-down direction. This can provide the disposable diaper 1 being seamless in the sheet in the entire abdominal portion 16a and the entire dorsal portion 16b and having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric.

[0051] Further, in this embodiment, the second sheet 12 is attached in a state where the high contraction stress region P1 corresponding to the first region 31 of the first sheet 11 and the low contraction stress region P2 corresponding to the second region 32 and the third region 33 are extended at a constant extension rate, to produce the exterior member 8. Thus, when the extension is released, the exterior member 8 can be provided with a uniform texture like a fabric in the entire region of the waist portion 16 irrespective of the regions having different magnitudes in contraction stress. Further, the exterior member 8 thus produced has an equal dimension in the circumferential direction in the first region 31 and the second region 32 of the exterior member 8 in a natural state and has mutually different contraction stresses in the circumferential direction of the trunk between the first region 31 and the second region 32.

[0052] Further, in this embodiment, the first region 31 positioned on the lower side of the waist portion 16 is configured to have a higher contraction stress than the contraction stress of the second region 32 and the third region 33 positioned on the upper side of the waist portion 16, which makes it possible to effectively prevent the disposable diaper 1 from slipping down during wearing. A wearer, particularly an infant, has a bulging abdominal region as a physical feature. If a tightening force for a portion, of the waist portion, which is to abut on the bulging abdominal region, is increased, because of the high tightening force, the waist portion of the disposable diaper is gradually squeezed and is likely to slip down to a slim part of the abdominal region.

In this embodiment, the first region 31 having a high contraction stress is provided to the lower side of the waist portion 16 such that a region of the waist portion 16 having a relatively high tightening force abuts on the slim part around the trunk, which makes it possible to effectively prevent the disposable diaper from slipping down during wearing. In order to effectively prevent such slipping down during wearing, the relationship of the contraction stress between the second region 32 and the third region 33 positioned on the upper side of the waist portion 16 and the first region 31 positioned on the lower side thereof is preferably set to the ranges described above.

[0053] In such a manner, in this embodiment, the abdominal portion 16a and the dorsal portion 16b are each configured to include the regions having mutually different contraction stresses by using a seamless stretchable non-woven fabric (first sheet 11), and thus the disposable diaper 1 having good fitting property and having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric while having the function of a diaper can be obtained.

[0054] Further, in this embodiment, the vicinity of the opening circumferential edge 15 of the waist opening 7 corresponds to the third region 33. The third region 33 has a higher contraction stress than the contraction stress of the second region 32 adjacently positioned immediately below the third region 33. Further, the third region 33 has a lower contraction stress than the contraction stress of the first region 31.

In general pants as underwear, rubber is used in the waist portion. In this embodiment, providing the third region 33 having a higher contraction stress than the contraction stress of the second region 32 can give a moderate tightening feeling at the waist opening end to a wearer when the disposable diaper is worn, and can provide a wearing feeling like pants as underwear to the wearer.

Further, providing the third region 33 can give a feeling of elongation like pants as underwear to an operating person, for example, at the wearing operation when the operating person widens the waist opening 7 of the disposable diaper 1 and passes the legs of a wearer into the leg openings 14.

[0055] Further, setting the length of the third region 33 in the front-back direction to the ranges described above can give a wearing feeling, which is similar to that of general pants as underwear in which rubber is used in the waist portion, to the wearer.

[0056] Further, in this embodiment, in the abdominal portion 16a and the dorsal portion 16b, the raised portions 35 form a sequence of patterns over the first region 31 and the second region 32. Thus, in the abdominal portion 16a and the dorsal portion 16b of the disposable diaper 1, a seamless smooth pattern is formed, and the disposable diaper 1 having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric can be obtained.

Further, each raised portion 35 forms a hollow portion extending along the up-down direction together with the first sheet 11. Simultaneously, when the disposable diaper is worn, the raised portion 35 forms a hollow portion extending along the up-down direction also between each raised portion 35 and the skin (outside of raised portion 35). The hollow portions, which are formed inside and outside of the raised portions 35, can function as ventilation passages through which air flows, and allow the composite sheet 10 to have excellent cushioning property and excellent air permeability.

[0057] <Other Embodiments> Hereinafter, second to seventh embodiments will be described as other embodiments. In any of the embodiments, as in the first embodiment, the composite sheet including the first sheet and the second sheet attached to each other via the bonding layer is used in the abdominal portion and the dorsal portion, and the composite sheet having a contraction stress distribution similar to that of the first embodiment is used in the waist portion of the exterior member.

[0058] Also in the following embodiments, as in the first embodiment, the first sheet including the first region and the second region having mutually different contraction stresses in the up-down direction is made of a single seamless stretchable non-woven fabric. Thus, the disposable diaper having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric in the entire abdominal portion and the entire dorsal portion can be obtained.

Further, also in the following embodiments, the first region positioned on the lower side of the waist portion is configured to have a higher contraction stress than the contraction stress of the second region and the third region positioned on the upper side of the waist portion, which makes it possible to effectively prevent the disposable diaper from slipping down during wearing. It should be noted that the contraction stress of the third region may be configured to be the same as that of the first contraction region, and the first region positioned on the lower side has a higher contraction stress than that of the second region positioned on the upper side, which similarly makes it possible to effectively prevent slipping down during wearing.

Further, also in the following embodiments, providing the third region having a higher contraction stress than the contraction stress of the second region can give a moderate tightening feeling at the waist opening end to a wearer when the disposable diaper is worn, and can provide a wearing feeling like underwear to the wearer. Further, providing the third region can give a feeling of elongation like underwear to an operating person, for example, at the wearing operation when the operating person widens the waist opening of the disposable diaper and passes the legs of a wearer into the leg openings.

Further, also in the following embodiments, the raised portions formed by the second sheet form a sequence of patterns over the first region and the second region in the waist portion. Thus, in the abdominal portion and the dorsal portion, a seamless smooth pattern is formed, and the disposable diaper having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric can be obtained.

Hereinafter, the second to seventh embodiments will be described in detail. Configurations similar to those in the first embodiment will be denoted by similar reference symbols and description thereof will be omitted in some cases.

[0059] <Second Embodiment> A disposable diaper 2 according to this embodiment will be described with reference to Figs. 1 and 8. Fig. 8 shows a state where folded-back portions 20 are not unfolded.

The disposable diaper 2 shown in Fig. 1 includes an exterior member 28 and an absorbent member 9. The disposable diaper 2 of this embodiment has a configuration in which an elastic member 29 is additionally provided to the configuration of the disposable diaper 1 shown in the first embodiment. As shown in Fig. 8, the elastic member 29 is disposed in a third region 33. For the form of the elastic member 29, a thread-like one such as a rubber thread, which has a rectangular, circular, or multangular cross-section, a string-like one such as a flat rubber thread, or the like can be used. The elastic member 29 is disposed along the circumferential direction of the trunk within a folded-back composite sheet (stretchable sheet) 10 in the third region 33.

[0060] The elastic member 29 is disposed in each of an abdominal portion 16a and a dorsal portion 16b over the entire width along the circumferential direction such that, in a natural state where no tension is applied, the elastic member 29 has a length equal to or larger than the width of each of the abdominal portion 16a and the dorsal portion 16b in a natural state.

Thus, in the disposable diaper 2 in a natural state, creases due to the elastic member 29 do not occur at an opening circumferential edge 15 of a waist opening 7, and the disposable diaper 2 having a neat appearance like underwear can be obtained.

Further, providing the elastic member 29 can retain stretch property at the end on the waist opening 7 side by the elastic member 29 even if the stretch property is destroyed and looseness occurs at the end on the waist opening 7 side of the first sheet 11 during use, and the disposable diaper 2 with a stable quality can be obtained.

Further, the elastic member 29 is extended when the disposable diaper 2 is worn, and a tightening feeling is given to the wearer. Thus, a feeling of use like underwear can be given to the wearer.

[0061] Next, examples in which the pattern form of the bonding layer is different from that of the first embodiment will be described as the third to sixth embodiments.

In the embodiments described above, the bonding layer has the pattern in which the plurality of bonding portions continuously extending along the up-down direction are disposed away from each other at regular intervals in the width direction, but the pattern of the bonding layer is not limited thereto. As shown in the following embodiments, in the abdominal portion and the dorsal portion, the plurality of bonding portions only need to be disposed at intervals therebetween in the circumferential direction and disposed continuously or discontinuously along one direction over the first region 31 and the second region 32.

Thus, the plurality of raised portions formed by the second sheet 12 form a sequence of patterns, and a seamless smooth pattern is formed in the entire abdominal portion and the entire dorsal portion.

[0062] The following third to sixth embodiments are different from the first embodiment in the pattern of the bonding layer and thus different only in the form of the pattern formed by the raised portions. Here, the pattern form of the bonding layer will be mainly described. While each of the following third to sixth embodiments will be described using a plan view showing an unfolded state of an exterior member of a disposable diaper, each of those plan views shows a state where the side seal portions of the disposable diaper shown in Fig. 1 are torn off to separate the abdominal portion and the dorsal portion from each other, and the exterior member is further extended and spread along the X-Y plane. Further, in order to describe an arrangement pattern of the bonding layer constituting part of the exterior member, each of those plan views of the exterior member omits illustration of the second sheet and illustrates only the first sheet and the bonding layer.

[0063] <Third Embodiment> A disposable diaper 3 according to this embodiment will be described with reference to Figs. 1 and 9.

The disposable diaper 3 shown in Fig. 1 includes an exterior member 38 and an absorbent member 9. The exterior member 38 shown in Fig. 9 includes a waist portion 36 and a crotch portion 37 that are continuously formed, and the waist portion 36 includes an abdominal portion 36a and a dorsal portion 36b. The exterior member 38 includes a first sheet 11 and a second sheet 12 attached to each other via a bonding layer 22.

[0064] The bonding layer 22 includes a plurality of bonding portions 25 that are disposed between the first sheet 11 and the second sheet 12 and each have a long thin belt-like shape continuously extending with an equal width in the width direction. The plurality of bonding portions 25 each have the same width and are disposed away from each other at regular intervals in the up-down direction. The bonding portions 25 are arranged in a sequence of patterns over the total length in the width direction of each of the abdominal portion 36a and the dorsal portion 36b including the stretchable regions of the exterior member 38.

[0065] The disposable diaper 3 of this embodiment includes a plurality of raised portions formed by the second sheet 12, which bulges in a direction away from the first sheet 11, between adjacent rows of the bonding portions 25 in a natural state. The raised portions each extend in the width direction and are formed away from each other at regular intervals in the up-down direction, to form folds with a uniform pattern in the in-plane direction on the inside of the waist portion 36 of the exterior member 38.

[0066] <Fourth Embodiment> A disposable diaper 4 according to this embodiment will be described with reference to Figs. 1 and 10.

The disposable diaper 4 shown in Fig. 1 includes an exterior member 48 and an absorbent member 9. The exterior member 48 shown in Fig. 10 includes a waist portion 46 and a crotch portion 47 that are continuously formed, and the waist portion 46 includes an abdominal portion 46a and a dorsal portion 46b. The exterior member 48 includes a first sheet 11 and a second sheet 12 attached to each other via a bonding layer 23.

[0067] The bonding layer 23 includes a plurality of bonding portions 26 disposed between the first sheet 11 and the second sheet 12. The plurality of bonding portions 26 each have a long thin belt-like shape continuously extending with an equal width in an oblique direction with respect to the width direction and the up-down direction. The plurality of bonding portions 26 each have the same width and are disposed away from each other at regular intervals. The bonding portions 26 are arranged in a sequence of oatterns over the entire abdominal portion 46a and the entire dorsal portion 46b including the stretchable regions of the exterior member 48.

The disposable diaper 4 includes a plurality of raised portions formed by the second sheet 12, which bulges in a direction away from the first sheet 11, between adjacent rows of the bonding portions 26 in a natural state. The raised portions each extend with an equal width obliquely with respect to the circumferential direction and the up-down direction and are arranged away from each other at regular intervals.

It should be noted that this embodiment has the form in which the bonding portions 26 each continuously extend on one straight line in the oblique direction, but the present invention is not limited thereto. For example, the plurality of bonding portions may constitute a bonding portion group in which the plurality of bonding portions are discontinuously disposed on one straight line in the oblique direction, and a plurality of such bonding portion groups may be intermittently disposed in the circumferential direction to constitute the bonding layer.

[0068] <Fifth Embodiment> A disposable diaper 5 according to this embodiment will be described with reference to Figs. 1 and 11.

The disposable diaper 5 shown in Fig. 1 includes an exterior member 58 and an absorbent member 9. The exterior member 58 shown in Fig. 11 includes a waist portion 56 and a crotch portion 57 that are continuously formed, and the waist portion 56 includes an abdominal portion 56a and a dorsal portion 56b. The exterior member 58 includes a first sheet 11 and a second sheet 12 attached to each other via a bonding layer 24.

[0069] The bonding layer 24 is includes a plurality of bonding portion groups 27 that are disposed between the first sheet 11 and the second sheet 12 and disposed away from each other at regular intervals in the circumferential direction of the trunk. Each bonding portion group 27 includes a plurality of bonding portions 27a intermittently disposed away from each other at regular intervals along the up-down direction. In other words, the bonding portion group 27 includes the plurality of bonding portions 27a discontinuously disposed on one straight line along the up-down direction.

The disposable diaper 5 in this embodiment includes a plurality of raised portions formed by the second sheet 12, which bulges in a direction away from the first sheet 11, between adjacent rows of the bonding portion groups 27 in a natural state. The raised portions are disposed in a matrix.

In the disposable diaper 5, the plurality of raised portions in the abdominal portion 56a and the dorsal portion 56b spatially communicate with each other through the hollow portions thereof, and thus good air permeability is obtained.

[0070] <Sixth Embodiment> A disposable diaper 6 according to this embodiment will be described with reference to Figs. 1 and 12.

The disposable diaper 6 shown in Fig. 1 includes an exterior member 68 and an absorbent member 9. The exterior member 68 shown in Fig. 12 includes a waist portion 66 and a crotch portion 67 that are continuously formed, and the waist portion 66 includes an abdominal portion 66a and a dorsal portion 66b. The exterior member 68 includes a first sheet 11 and a second sheet 12 attached to each other via a bonding layer 63.

[0071] The bonding layer 63 includes a plurality of bonding portions 64 disposed between the first sheet 11 and the second sheet 12 in a staggered manner. The plurality of bonding portions 64 are intermittently disposed at intervals therebetween in the circumferential direction of the trunk and intermittently disposed at intervals therebetween also in the up-down direction. The plurality of bonding portions 64 are discontinuously disposed along the up-down direction. Here, the staggered manner indicates an arrangement in which, between adjacent bonding portion groups each including the plurality of bonding portions 64 discontinuously disposed along the up-down direction, the bonding portions are alternately disposed.

The disposable diaper 6 includes a plurality of raised portions formed by the second sheet 12, which bulges in a direction away from the first sheet 11, between adjacent bonding portions 64 in a natural state. The plurality of raised portions are arranged in a staggered manner.

Since the disposable diaper 6 includes a plurality of raised portions almost uniformly in both the width direction and the up-down direction in the entire abdominal portion 66a and the entire dorsal portion 66b, the exterior member 68 having a cushioning feeling and a soft-looking impression can be obtained.

[0072] While the embodiments described above have described some examples of the bonding layer pattern, the present invention is not limited to those patterns. For example, the first, fourth, fifth, and sixth embodiments have described the examples in which the bonding portions continuously extending in the up-down direction or the oblique direction or the bonding portion groups each including a plurality of bonding portions discontinuously disposed are arranged at regular intervals in the circumferential direction.

In contrast to this, the bonding portions or the bonding portion groups extending along the up-down direction or the oblique direction may also be arranged at different arrangement intervals in the circumferential direction. For example, in each of the dorsal portion and the abdominal portion that constitute the waist portion, an arrangement interval between the bonding portions or bonding portion groups disposed in both side portions in the width direction, which are close to the side seal portions, may be narrower than an arrangement interval width for the bonding portions or bonding portion groups at the center portion in the width direction. Further, the arrangement interval may be changed to be narrower stepwisely or continuously from the center portion toward the both side portions of each of the dorsal portion and the abdominal portion.

Even if the arrangement interval between the bonding portions in the width direction is changed to intermittently arrange the bonding portions in such a manner, the high contraction stress region P1 and the low contraction stress region P2 disposed along the up-down direction have the same arrangement pattern for the bonding portions. Thus, the plurality of raised portions formed by the second sheet form a sequence of patterns over the high contraction stress regions P1 and the low contraction stress regions P2.

Thus, in the entire abdominal portion and the entire dorsal portion, a seamless smooth pattern is formed from the high contraction stress region P1 to the low contraction stress region P2.

[0073] <Seventh Embodiment> The first embodiment has described the example in which the thickness of the elastic fibers constituting the elastic resin is made different to constitute the first sheet 11 including the high contraction stress regions P1 and the low contraction stress regions P2, but the present invention is not limited thereto.

For example, the arrangement interval between the elastic filaments may be made different.

In a first sheet 50 shown in Fig. 13, elastic filaments 62 constituting an elastic resin are made of elastic fibers having the same thickness, for example, here, having a thickness of 100 pm in the first region 31 to be the high contraction stress region P1 and in the second region 32 to be the low contraction stress region P2. A plurality of elastic filaments 62a used for the first region 31 and a plurality of elastic filaments 62b used for the second region 32 extend along the circumferential direction and are disposed at intervals therebetween in the up-down direction.

An arrangement interval between the elastic filaments 62a in the first region 31 is narrower than an arrangement interval between the elastic filaments 62b in the second region 32. Thus, the contraction stress of the first region 31 can be set higher than the contraction stress of the second region 32.

The arrangement interval between the elastic filaments 62a disposed in the first region 31 is preferably 0.2 mm or more and more preferably 0.5 mm or more, and further, preferably 2.5 mm or less and more preferably 2 mm or less.

The above-mentioned arrangement interval is preferably 0.2 mm or more and 2.5 mm or less, and more preferably 0.5 mm or more and 2 mm or less.

The arrangement interval between the elastic filaments 62b disposed in the second region 32 is preferably 0.5 mm or more and more preferably 0.8 mm or more, and further, preferably 5.0 mm or less and more preferably 3.0 mm or less. The above-mentioned arrangement interval is preferably 0.5 mm or more and 5.0 mm or less, and more preferably 0.8 mm or more and 3.0 mm or less.

The arrangement interval between the elastic filaments 62b disposed in the second region 32 is preferably 1.2 times or more and more preferably 1.5 times or more the arrangement interval between the elastic filaments 62a disposed in the first region 31, and further, preferably 3 times or less and more preferably 2.5 times or less the arrangement interval between the elastic filaments 62a disposed in the first region 31. The above-mentioned arrangement interval is preferably 1.2 times or more and 3 times or less, and more preferably 1.5 times or more and 2.5 times or less the arrangement interval between the elastic filaments 62a disposed in the first region 31.

[0074] Alternatively, the contraction stress of the first region 31 may be set to be higher than the contraction stress of the second region 32 by making the weight of the elastic resin per unit area of the first region 31 heavier than the weight of the second region 32.

The weight per unit area of the elastic resin disposed in the first region 31 is preferably 5 g/m2 or more and more preferably 7 g/m2 or more, and further, preferably 15 g/m2 or less and more preferably 12 g/m2 or less. The weight per unit area of the elastic resin disposed in the first region 31 is preferably 5 g/m2 or more and 15 g/m2 or less, and more preferably 7 g/m2 or more and 12 g/m2 or less.

The weight per unit area of the elastic resin disposed in the second region 32 is preferably 4 g/m2 or more and more preferably 5 g/m2 or more, and further, preferably 12 g/m2 or less and more preferably 10 g/m2 or less. The weight per unit area of the elastic resin disposed in the second region 32 is preferably 4 g/m2 or more and 12 g/m2 or less, and more preferably 5 g/m2 or more and 10 g/m2 or less.

The weight per unit area of the elastic resin used in the first region 31 is preferably 1.2 times or more and more preferably 1.5 times or more that in the second region 32, and further, preferably 3 times or less and more preferably 2.5 times or less that in the second region 32. The weight per unit area of the elastic resin used in the first region 31 is preferably 1.2 times or more and 3 times or less, and more preferably 1.5 times or more and 2.5 times or less that in the second region 32.

[0075] Alternatively, the contraction stress of the first region 31 may be set to be higher than the contraction stress of the second region 32 by making the density of the plurality of elastic fibers constituting the elastic resin of the first region 31 higher than the density of the plurality of elastic fibers constituting the elastic resin of the second region 32.

The density of the plurality of elastic fibers constituting the elastic resin used in the first region 31 is preferably 1.2 times or more and more preferably 1.5 times or more that in the second region 32, and further, preferably 3 times or less and more preferably 2.5 times or less that in the second region 32. The density of the plurality of elastic fibers constituting the elastic resin used in the first region 31 is preferably 1.2 times or more and 3 times or less, and more preferably 1.5 times or more and 2.5 times or less that in the second region 32.

[0076] <Still Other Embodiments> Hereinabove, the embodiments of the present invention have been described, but the present invention is not limited to the embodiments described above and can be variously modified without departing from the gist of the present invention.

For example, in the embodiments described above, the bonding layer is provided such that the raised portions form a sequence of patterns. However, at the production of the exterior member, it is only necessary to extend the first sheet at a constant extension rate and attach the second sheet thereto, and it is not necessary to provide the bonding layer such that the raised portions are formed in a sequence of patterns. The first sheet is extended at a constant extension rate and the second sheet is attached thereto to produce the exterior member, and thus the disposable diaper having an appearance and the sense of touch like pants as underwear having a uniform texture over a plurality of regions having different contraction stresses of the exterior member can be obtained.

[0077] Further, in the embodiments described above, the exterior member includes the first sheet and the second sheet, but the exterior member may include only the first sheet (stretchable sheet). The side seal portions may be formed in a state where the abdominal portion and the dorsal portion are extended at a constant extension rate, and then attached to each other.

Further, in the embodiments described above, both the abdominal portion and the dorsal portion of the waist portion include the stretchable regions, but at least one of the abdominal portion or the dorsal portion may include a stretchable region.

Further, in the waist portion of the exterior member in the embodiments described above, a laminate sheet in which the first sheet (stretchable sheet) and the second sheet (non-stretchable sheet) are laminated is used, and when the laminate sheet is applied to the disposable diaper, the first sheet being a stretchable sheet is disposed on the outer surface side and the second sheet is disposed on the inner surface side. However, the first sheet may be disposed on the inner surface side and the second sheet may be disposed on the outer surface side. In such a configuration, the raised portions are formed on the outer surface of the disposable diaper and form a sequence of patterns, and thus the waist portion of the disposable diaper can be provided with an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric having a sense of unity as a whole.

[0078] Further, the embodiments described above have described the example in which the folded-back portion obtained by folding back the first sheet is provided at the opening circumferential edge of the waist opening, but the folded-back portion does not need to be provided. In this case, the exterior member includes a composite sheet in which a first sheet (stretchable sheet) and a second sheet (non-stretchable sheet) having the same outer shape are laminated. It should be noted that also in the case where the exterior member includes only the first sheet, the folded-back portion may be provided, or no folded-back portion may be orovided. In the case where no folded-back portion is provided, for example, when the bonding layer patterns as in the first, fourth, fifth, and sixth embodiments are provided, the raised portions form an opening together with the first sheet at the opening circumferential edge of the waist opening. Thus, the air flowing inside the raised portions each having a hollow shape easily flows to the outside of the disposable diaper via the opening formed by the raised portions, which provides more excellent air permeability.

[0079] Further, in the embodiments described above, part of an elastic element of the stretchable sheet in a region, of the waist portion, facing the absorbent member may be cut or removed to obtain a non-stretchable region. This allows no creases to occur in the absorbent member due to the action of the contraction of the stretchable sheet on the absorbent member and does not inhibit liquid absorbing performance of the absorbent member.

[0080] Further, the pant-type absorbent article according to the present invention does not need to be a pull-on disposable diaper that is formed into a pants shape in advance by joining with the side seal portions as in the embodiments described above. In other words, the pant-type absorbent article according to the present invention may be a tape-type disposable diaper that includes a tape such as a hook-and-loop fastener instead of the side seal portions and takes a pants shape by attaching the tape when the diaper is to be worn.

[0081] Moreover, the pant-type absorbent article according to the present invention does not need to be a disposable diaper for a baby or infant and may be, for example, a disposable diaper for an adult or a child. Moreover, the pant-type absorbent article according to the present invention does not need to be a disposable diaper as long as it is an absorbent article of a type to be worn on the lower half of a body. Examples of such a pant-type absorbent article include a pull-on sanitary napkin and a pull-on incontinence pad.

[0082] Next, description will be given on the stretchable sheet including the high contraction stress regions P1 and the low contraction stress regions P2, which is applicable to the above-mentioned pant-type absorbent article.

[0083] The stretchable sheet according to the present invention is a sheet that is seamless and continuous in a planar direction and that includes a plurality of regions having mutually different tensile stresses due to contraction (hereinafter, referred to as contraction stress). Means for forming a sheet including a plurality of regions having mutually different tensile stresses due to contraction includes means for constituting a sheet by connecting a plurality of separate sheets having different contraction stresses. The stretchable sheet according to the present invention is not constituted by connecting a plurality of separate sheets and thus has not only excellent strength with respect to an external force such as a contact with an object or a grip by a handler but also an appearance having a sense of unity as a whole. Additionally, with the seamless configuration, extension is not limited in the vicinity of seams generated when the separate sheets are connected to each other in the contracted state, contraction is not limited in the vicinity of seams generated when the separate sheets are connected to each other in the extended state, and a strain such as a crease is prevented from occurring in the stretchable sheet. Thus, it is preferably to provide no seams. Here, the contraction stress refers to a tensile stress due to contraction obtained when the stretchable sheet in a natural state is extended and then returns to the original state by contraction. Further, in this specification, unless otherwise specifically described, the natural state indicates a state where the stretchable sheet is placed still on a horizontal plane without applying an external force that causes deformation such as extension or crush. In addition, for example, in the case where such a stretchable sheet is used for the exterior member of the absorbent article, because of the seamless configuration, oozing or wetting and spreading of excreta, and leakage to the outside of the article are less likely to occur.

Such a stretchable sheet is suitable for an exterior member of a pull-on disposable diaper that is, for example, an absorbent article that needs stretch property around a trunk.

[0084] <Eighth Embodiment> Hereinafter, description will be sequentially given on a stretchable sheet, a stretching apparatus used at the time of production of a stretchable sheet, a method of producing a stretchable sheet, and a pull-on disposable diaper using the stretchable sheet according to an eighth embodiment.

[0085] [Configuration of Stretchable Sheet] First, a stretchable sheet according to the first embodiment will be described with reference to Figs. 14 to 17.

A stretchable sheet 70 includes a plurality of elastic filaments 87a and two layers of a first non-woven fabric 85 and a second non-woven fabric 86 that are disposed facing each other via the elastic filaments 87a.

The plurality of elastic filaments 87a are stretchable in a first direction (Y-axis direction) and constitute an elastic layer 87. The plurality of elastic filaments 87a allows the stretchable sheet 70 to be stretchable in the Y-axis direction. The Y-axis direction corresponds to a stretching direction of the stretchable sheet 70. The Z-axis direction corresponds to a thickness direction of the stretchable sheet 70. The X-axis direction as a second direction corresponds to a direction orthogonal to the stretching direction and the thickness direction.

[0086] The first non-woven fabric 85 and the second non-woven fabric 86 are not limited to specific kinds and are selectable from, for example, an air-through non-woven fabric, a heat roll non-woven fabric, a spun lace non-woven fabric, a spun-bonded non-woven fabric, and a melt-blown non-woven fabric.

Further, the fiber constituting the non-woven fabric is not limited to a specific kind and is selectable from, for example, chemical fibers of polyethylene, polypropylene, polyester, polyamide, and the like. Moreover, the non-woven fabric may be a composite fiber including a plurality of kinds of chemical fibers. In addition, the fiber constituting the non-woven fabric may contain natural fibers such as cotton and silk, for example.

[0087] In this embodiment, the first non-woven fabric 85 and the second non-woven fabric 86 are the same kind of nonwoven fabric.

The elastic filaments 87a are thread-like elastic members extending along the Y-axis direction. The filaments 87a are arranged at regular intervals in the X-axis direction orthogonal to the Y-axis direction. The elastic filaments 87a are directly welded to each of the first non-woven fabric 85 and the second non-woven fabric 86. In other words, the elastic filaments 87a, the first non-woven fabric 85, and the second non-woven fabric 86 are joined via no adhesives or the like. In such a manner, the first non-woven fabric 85, the second non-woven fabric 86, and the elastic filaments 87a sandwiched between those non-woven fabrics are fused to constitute the stretchable sheet 70, and thus the elastic filaments 87a are contained in the non-woven fabric layer without being exposed from a surface of the stretchable sheet 70. The stretchable sheet 70 is configured to be stretchable by itself.

[0088] The elastic filaments 87a are formed of, for example, an elastic material such as thermoplastic elastomer.

In particular, the elastic filaments 87a are preferably formed of thermoplastic elastomer, which is easily fused to the fiber constituting the non-woven fabric.

For the thermoplastic elastomer to from the elastic filaments, for example, styrene elastomer, olefinic elastomer, polyester elastomer, polyurethane elastomer, and the like can be used. Further, the elastic filaments can be formed in combination of a plurality of kinds of thermoplastic elastomer. Moreover, the elastic filaments may be a core-sheath type or side-by-side type composite fiber.

[0089] In this embodiment, as shown in Figs. 14 and 15, the elastic filaments 87a are formed into a corrugated shape in a natural state. The stretchable sheet 70 also has a corrugated shape along the corrugated shape of the elastic filaments 87a. In other words, a boundary surface between the first non-woven fabric 85 and the second non-woven fabric 86 is formed into a corrugated shape along the corrugated shape of the elastic filaments 87a.

The corrugated-shaped stretchable sheet 70 has a corrugated shape in which top portions 81 positioned on the first non-woven fabric 85 side and trough portions 82 positioned on the second non-woven fabric 86 side are alternately arranged. The top portions 81 and the trough portions 82 are continuous with each other via wall portions 83.

[0090] The first non-woven fabric 85 (second non-woven fabric 86) includes a plurality of projections 74 (71) and a plurality of flat portions 75 (72), which are made of the fiber constituting the non-woven fabric. As shown in Fig. 16, in a state where the corrugated shape of the stretchable sheet 70 is elongated into a planar shape, the projections 74 (71) and the flat portions 75 (72) are extended in the X-axis direction and alternately arranged along the Y-axis direction.

It should be noted that this embodiment describes as an example a case where the boundary surface between the first non-woven fabric 85 and the second non-woven fabric 86 has the corrugated shape in a natural state, but the boundary surface may have a planar shape. In this case, the stretchable sheet takes the form as shown in Fig. 16 in a natural state.

In this embodiment, as shown in Figs. 14 and 15, the projections 74 and the projections 71 are positioned in the wall portions 83 of the stretchable sheet 70 having the corrugated shape. The flat portions 75 and the flat portions 72 are positioned in the top portions 81 or the trough portions 82 of the stretchable sheet 70 having the corrugated shape.

[0091] In such a manner, in this embodiment, in addition to the projections 74 provided to the first non-woven fabric 85 and the projections 71 provided to the second non-woven fabric 86, the stretchable sheet 70 has the corrugated shape. Thus, when the stretchable sheet 70 is used for the exterior member of a disposable diaper, a contact area between the skin of a wearer of the disposable diaper and the stretchable sheet 70 can be reduced, and stuffiness, rash, and the like can be effectively prevent from occurring. Moreover, since the difference between the length of the stretchable sheet 70 in the Y-axis direction in a natural state and the length thereof when extended can be increased, the disposable diaper can be applied to wearers of wide variety of body types.

[0092] The fiber constituting the projections 74 and the projections 71 is a fiber that is plastically deformed by roll stretching, which will be described later, and that remains extended by the roll stretching, and is further a fiber that is peeled from the elastic filaments 87a by the roll stretching. The fiber constituting the flat portions 75 and the flat portions 72 is a fiber that is not plastically deformed by the roll stretching to be described later.

The projections 74 (71) form stretchable portions of the first non-woven fabric 85 (second non-woven fabric 86), and the flat portions 75 (72) form connection portions of the first non-woven fabric 85 (second non-woven fabric 86). The stretchable portions and the connection portions will be described later.

The density of the fiber of the projections 74 (71) is relatively lower than the density of the fiber of the flat portions 75 (72).

In this embodiment, in the thickness direction, a projection 71 on one surface of the stretchable sheet 70 is configured to be positioned at a position of a projection 74 on the other surface, and a flat portion 72 on the one surface is configured to be positioned at a position of a flat portion 75 on the other surface. In such a manner, in this embodiment, the projections 74 and the projections 71 have an almost plane-symmetric shape on the boundary surface between the first non-woven fabric 85 and the second non-woven fabric 86. Moreover, the regions to be the connection portions of the first non-woven fabric 85 and the second nonwoven fabric 86 are also positioned facing each other in the thickness direction of the stretchable sheet 70.

Thus, this embodiment will be described without distinguishing the stretchable portions and the connection portions of the first non-woven fabric 85, and the stretchable portions and the connection portions of the second non-woven fabric 86 from each other. The stretchable portions of both the non-woven fabrics are referred to as stretchable portions 70a of the stretchable sheet 70, and the connection portions of both the non-woven fabrics are referred to as connection portions 70b of the stretchable sheet 70.

[0093] Part of the fiber constituting the first non-woven fabric 85 (second non-woven fabric 86) is peeled from the elastic filaments 87a and plastically deformed, and in the stretchable sheet 70 in a natural state, protrudes in a loop shape to form the projections 74 (projections 71). The projections 74 (projections 71) are room for extension when the stretchable sheet 70 is extended. A region in which the fiber of the non-woven fabrics thus plastically deformed is disposed is the stretchable portion 70a of the stretchable sheet 70. In such a manner, the projections 74 and the projections 71 constitute the stretchable portions 70a stretchable in the Y-axis direction.

Meanwhile, of the fiber constituting the first non-woven fabric 85 (second non-woven fabric 86), a fiber that is not extended by roll stretching and is not plastically deformed is a fiber with a length that is little changed from the length before being subjected to the roll stretching. Such a fiber forms the flat portions 75 (72). A region in which such a fiber of the non-woven fabrics, which is not plastically deformed, is disposed is the connection portion 70b of the stretchable sheet 70. In such a manner, the flat portions 75 and the flat portions 72 constitute the connection portions 70b that are more difficult to extend and contract in the Y-axis direction than the stretchable portions 70a.

Thus, a welded-joined region per unit area between the elastic filaments 87a and the first non-woven fabric 85 (second non-woven fabric 86) in the stretchable portions 70a is smaller than that in the connection portions 70b.

[0094] As shown in Fig. 17, in the stretchable sheet 70, the stretchable portions 70a and the connection portions 70b that each extend in the X-axis direction are intermittently disposed and alternately arranged along the Y-axis direction. The connection portions 70b are intermittently disposed along the Y-axis direction and extend along the X-axis direction.

The connection portion 70b is disposed between stretchable portions 70a adjacent to each other among the plurality of stretchable portions 70a and connects the stretchable portions 70a adjacent to each other.

In the extended state of the stretchable sheet 70, when a force to extend in the Y-axis direction is applied, the stretchable portions 70a are mainly extended in the Y-axis direction. In other words, the stretchable sheet 70 in the extended state is not substantially extended in the connection portions 70b. It should be noted that the stretchable sheet 70 in the extended state may be extended also in the connection portions 70b by a smaller amount than in the stretchable portions 70a.

When the force to extend in the Y-axis direction is released from the extended state, the stretchable sheet 70 is contracted in the Y-axis direction due to the elastic force of the elastic filaments 87a. The stretchable sheet 70 in the contracted state has a smaller dimension of the stretchable portion 70a in the Y-axis direction than that in the stretchable sheet 70 in the extended state. In such a manner, in the stretchable sheet 70, the stretchable sheet 70 is stretchable by itself due to the elastic force of the elastic filaments 87a without having a configuration including an elastic member such as a rubber thread.

[0095] As shown in (A) of Fig. 18, in the stretchable sheet 70 in a natural state, the elastic filaments 87a are not extended and are in a contracted state. The fiber constituting the first non-woven fabric 85 (second non-woven fabric 86) forms the projections 74 (71) in the stretchable portions 70a, and the projections 74 (71) protrude in a direction away from the elastic filaments 87a.

As shown in (B) of Fig. 18, in the stretchable portions 70a of the stretchable sheet 70 in the extended state, the fiber of the first non-woven fabric 85 constituting the projections 74 and the fiber of the second non-woven fabric 86 constituting the projections 71 are plastically deformed and extended by roll stretching, and thus portions having protruded in association with the contraction of the elastic filaments 87a are pulled so as to be straight. Meanwhile, in the connection portions 70b, the fiber of the non-woven fabrics positioned in the connection portions 70b are not plastically deformed and are difficult to extend.

[0096] In this embodiment, the plurality of projections 74 and projections 71 seamlessly continuously extend along the X-axis direction and are projections having partially different heights as shown in Figs. 14 to 17.

Each projection 74 (71) includes high projections 74b (71b) as second projections, and low projections 74a (71a) as first projections, which have mutually different heights along the X-axis direction. As shown in Figs. 15 and 16, the high projections 74b (71b) have a higher height and a lower fiber density than those of the low projections 74a (71a).

Such high projections 74b (71b) and low projections 74a (71a) having different fiber densities can be formed by adjusting the amount of mesh in a tooth space at the time of roll stretching using toothed stretching rolls, or the like. The production method will be described later.

In the stretchable portions 70a of the stretchable sheet 70 in the extended state, when the stretchable sheet 70 is extended, the portions having protruded in a loop shape are pulled so as to be straight in association with the extension of the elastic filaments 87a. In other words, as the height of the projections becomes higher, the extension amount at the time of extension increases.

[0097] Therefore, the stretchable portions 70a in which the high projections 74b (71b) are positioned have a larger extension amount at the time of extension than the extension amount of the stretchable portions 70a in which the low projections 74a (71a) are positioned. Thus, in the stretchable sheet 70, a possible extension amount at the time of extension differs between the region in which the high projections 74b (71b) are positioned and the region in which the low projections 74a (71a) are positioned. In other words, the region in which the high projections 74b (71b) are positioned is easier to extend than the region in which the low projections 74a (71a) are positioned. When both the regions are extended at the same extension rate, the contraction stress of the stretchable sheet 70 to return to the original state is higher in the region in which the low projections 74a (71a) are positioned than in the region in which the high projections 74b (71b) are positioned.

[0098] As shown in Figs. 14 and 16, in the stretchable sheet 70, a region in which the plurality of high projections 74b (71b) extending in the X-axis direction are disposed away from each other in the Y-axis direction constitutes a low contraction stress region P2. A region in which the plurality of low projections 74a (71a) extending in the X-axis direction are disposed away from each other in the Y-axis direction constitutes a high contraction stress region P1.

In each of the high contraction stress region P1 and the low contraction stress region P2, the plurality of elastic filaments 87a are arranged at regular arrangement intervals. In the stretchable sheet 70 of this embodiment, the low contraction stress region P2, the high contraction stress region P1, and the low contraction stress region P2 are sequentially positioned along the X-axis direction. The stretchable sheet 70 is a sheet in which a region in the center portion in the X-axis direction has a higher contraction stress than the contraction stress of the other regions.

Thus, as shown in Fig. 19, when the stretchable sheet 70 is extended in the Y-axis direction at a uniform extension rate, the upper portion and the lower portion of the stretchable sheet 70 in the X-axis direction are easily extended, and the center portion thereof is difficult to extend. Thus, the center portion in the X-axis direction has a constricted shape.

[0099] While the first non-woven fabric 85 will be described as an example with reference to Fig. 21, the second non-woven fabric 86 also have a configuration similar to the configuration of the first non-woven fabric 85.

The first non-woven fabric 85 is formed by, for example, a spunbonding method in this embodiment, and is subjected to embossing to obtain a plurality of thermally-fused portions 61. The thermally-fused portions 61 are formed in a constant pattern over the entire surface of the first non-woven fabric 85, and can thus provide a uniform touch feeling in the in-plane direction as a whole. It should be noted that the thermally-fused portion in the present invention means a portion in which the fibers in the non-woven fabric are thermally fused to each other. The non-woven fabric is not necessarily subjected to embossing. For example, a spot at which fibers are fused to each other by hot air in an air-through non-woven fabric is also the thermally-fused portion in the present invention.

[0100] When the stretchable sheet 70 is formed using the first non-woven fabric 85, the thermally-fused portions 61 are also disposed away from each other, in some cases, on a boundary 69 between the high contraction stress region P1 and the low contraction stress region P2 of the first non-woven fabric 85. Here, assumed is a rectangular thermally-fusedportion-non-existence region 65, which is surrounded by the thermally-fused portions 61 disposed adjacently to each other on the boundary 69 and the thermally-fused portions 61 disposed adjacently to each other along the X-axis direction via the boundary 69. Each side of the rectangular thermallyfused-portion-non-existence region 65 is parallel to the boundary 69 (extending in the Y-axis direction) or an imaginary line (extending in the X-axis direction) orthogonal to the boundary 69, and is in contact with the thermally-fused portion 61. The thermally-fused-portion-non-existence region 65 desirably has a longer length in the X-axis direction than the length in the Y-axis direction. This can makes it difficult to cause material fracture of the first non-woven fabric 85.

[0101] In general, the thermally-fused portions (embossed portions) formed by embossing have a reduced thickness as compared to a region other than the embossed portions, and there are steps in the vicinity of the margin of the embossed portion. Moreover, the embossed portions are likely to be deteriorated and broken due to the impact of heat, and the margin of the embossed portion is likely to be a start point of the material fracture.

In the present invention, when the stretchable sheet 70 is extended, a force in a shear direction acts in the boundary 69 between the high contraction stress region P1 and the low contraction stress region P2. Here, in the thermally-fused-portion-non-existence region 65, the length of the thermally-fused-portion-non-existence region 65 in the X-axis direction is set to be longer than the length thereof in the Y-axis direction, and thus the amount of displacement at the time of extension can be reduced as compared to a case where the length in the Y-axis direction is longer than the length in the X-axis direction.

Therefore, in the vicinity of the boundary 69 in which a load is likely to be applied to the material by the extension of the stretchable sheet 70, sufficient strength can be obtained without using a separate support for ensuring the strength.

It should be noted that, in the stretchable sheet 70, the length of the thermally-fused-portion-non-existence region 65 in the X-axis direction only needs to be longer than the length thereof in the Y-axis direction in at least one of the first non-woven fabric 85 and the second non-woven fabric 86.

[0102] [Stretching Apparatus] Next, a stretching apparatus used to produce the stretchable sheet 70 described above will be described with reference to Figs. 22 and 23. The stretchable sheet 70 described above is produced when a laminate 70' to be described later is subjected to roll stretching using a stretching apparatus.

A stretching apparatus 90 includes a pair of toothed stretching rolls 91 and 92. It should be noted that drive means (not shown) for driving the rolls is connected to each roll of the stretching apparatus 90. The drive means rotates each roll.

On the circumferential surface of the toothed stretching roll 91 (92), a plurality of teeth 79 (80) are provided radially from a rotation shaft in a direction orthogonal to the rotation direction of the roll, and recesses/projections are formed by those teeth along the rotation direction. In the recesses/projections, the projections correspond to the teeth 79 (80), and the recesses correspond to grooves each positioned between adjacent teeth 79 (80).

[0103] Hereinafter, a sheet in a state before the stretchable sheet 70 is subjected to roll stretching is referred to as the laminate 70' and is distinguished from a stretchable sheet 70 that has been subjected to roll stretching and has stretch property. The laminate 70' is formed by supplying heated elastic filaments 87a between two fabrics, which are to be base materials, an unprocessed first non-woven fabric (denoted by reference symbol 85' in Fig. 24 to be described later) and an unprocessed second non-woven fabric (denoted by reference symbol 86' in Fig. 24 to be described later), and by laminating them with a pressure. In the laminate 70', the elastic filaments 87a are directly welded to the unprocessed first non-woven fabric 85' and the unprocessed second non-woven fabric 86' by the heat of the elastic filaments 87a obtained by melt spinning. The unprocessed first non-woven fabric 85' and the unprocessed second non-woven fabric 86' each include the plurality of thermally-fused portions 61.

[0104] The laminate 70' is sandwiched between the pair of toothed stretching rolls 91 and 92 and is fed by the rotation of the toothed stretching rolls 91 and 92. The laminate 70' is caused to pass between the teeth 79 of one toothed stretching roll 91 and the grooves of the toothed stretching roll 92 that face and are meshed with the teeth 79, and between the teeth 80 of the toothed stretching roll 92 and the grooves of the toothed stretching roll 91 that face and are meshed with the teeth 80, thus performing roll stretching. As shown in (B) of Fig. 23, the tooth 79 (80) includes large depth portions 77b (78b) and a small depth portion 77a (78a) having a smaller depth than the depth of the large depth portions 77b (78b).

In this embodiment, in the tooth 79 (80), the small depth portion 77a (78a) is positioned in the center portion obtained when the tooth is equally divided into three along an axial direction orthogonal to the rotation direction. The large depth portions 77b (78b) are positioned on both sides of the small depth portion 77a (78a), and the tooth 79 (80) has a small depth in the center portion along the axial direction.

A region in which the small depth portion 77a of the tooth 79 is positioned and a region in which the small depth portion 78a of the tooth 80 is positioned face each other, and a region in which the large depth portions 77b of the tooth 79 are positioned and a region in which the large depth portions 78b of the tooth 80 are positioned face each other by roll stretching.

[0105] Further, in this embodiment, a web roll 76 formed of the wound-up laminate 70' is rotatably provided on the upstream side of the toothed stretching rolls 91 and 92 in the stretching apparatus 90, and the laminate 70' can be drawn out in the direction of the arrow C. A pair of infeed rolls 93 is provided between the web roll 76 and the above-mentioned toothed stretching rolls 91 and 92.

When the rotation rate of the infeed rolls 93 is adjusted, the supply rate of the laminate 70' to be supplied between the toothed stretching rolls 91 and 92 is adjusted. The laminate 70' can be supplied between the toothed stretching rolls 91 and 92 while a tension is being applied by the pair of infeed rolls 93 and the toothed stretching rolls 91 and 92.

[0106] Moreover, a pair of outfeed rolls 94 is orovided on the downstream side of the toothed stretching rolls 91 and 92.

When the rotation rate of the pair of outfeed rolls 94 is adjusted, the feed rate of the stretchable sheet 70 fed from between the toothed stretching rolls 91 and 92 is adjusted.

The stretchable sheet 70 subjected to roll stretching is then fed by the outfeed rolls 94 in the direction of the arrow D. The stretchable sheet 70 is drawn out between the toothed stretching rolls 91 and 92 while a tension is being applied by the outfeed rolls 94. Since the stretchable sheet is easily extended by a small tension, a tension to be applied by the pair of outfeed rolls 94 to the stretchable sheet 70 obtained after the stretching is preferably made weaker than a tension to be applied by the pair of infeed rolls 93 to the laminate 70' before stretching.

[0107] The laminate 70' that has passed between the pair of infeed rolls 93 is not yet subjected to roll stretching and is thus not provided with stretch property. The laminate 70' provided with no stretch property is subjected to roll stretching by the mesh of the teeth 79 and the teeth 80 while being positioned between the toothed stretching rolls 91 and 92, and the stretchable portions 70a and the connection portions 70b are formed. Thus, the stretch property is generated in the stretchable sheet 70.

Adjusting the degree of stretching in the regions to be the stretchable portions 70a is performed by adjusting the rotation rate of the toothed stretching rolls 91 and 92 and the rotation rate of the pair of infeed rolls 93. By adjusting a ratio of the rotation rate of the infeed rolls 93 and the rotation rate of the toothed stretching rolls 91 and 92, a tension to be applied to the laminate 70' when the laminate 70' is loaded to the toothed stretching rolls 91 and 92 is adjusted. For example, in the case where the height of the projections 74 formed of the non-woven fabric in the stretchable portions 70a is relatively increased, a tension to be applied to the laminate 70' to be loaded between the toothed stretching rolls 91 and 92 is strengthened.

[0108] The amount of mesh between the small depth portion 77a and the small depth portion 78a is configured to be smaller than the amount of mesh between the large depth portion 77b and the large depth portion 78b. Thus, a draw ratio in the region in which the large depth portion 77b and the large depth portion 78b are meshed with each other is higher than that in the region in which the small depth portion 77a and the small depth portion 78a are meshed with each other.

[0109] In regions of the laminate 70', which are processed at a relatively high draw ratio, the high projections 74b and the high projections 71b are formed. Regions passing between the large depth portions 77b of the teeth 79 and the large depth portions 78b of the teeth 80 of the laminate 70' become the low contraction stress regions P2 in which the high projections 74b and the high projections 71b of the stretchable sheet 70 are formed.

Meanwhile, in a region of the laminate 70', which is processed at a relatively low draw ratio, the low projections 74a and the low projections 71a are formed. A region passing between the small depth portions 77a of the teeth 79 and the small depth portions 78a of the teeth 80 of the laminate 70' becomes the high contraction stress region P1 in which the low projections 74a and the low projections 71a of the stretchable sheet 70 are formed.

[0110] In such a manner, in the roll stretching of this embodiment, providing regions having different amounts of mesh between the upper and lower teeth leads to performing processing on the laminate 70' such that the draw ratio differs in each region, thus forming the projections 74 (71) including the high projections 74b (71b) and the low projections 74a (71a).

Further, adjusting the ratio of the rotation rate of the infeed rolls 93 and the rotation rate of the toothed stretching rolls 91 and 92 can appropriately set the draw ratio.

It should be noted that in this embodiment the teeth of each of the toothed stretching rolls 91 and 92 include the large depth portions and the small depth portions. However, only the teeth of one of the toothed stretching rolls may include the large depth portions and the small depth portions, and the teeth of the other toothed stretching roll may have the same depth in the axial direction.

[0111] [Method of Producing Stretchable Sheet] Next, a method of producing the stretchable sheet 70 using the above-mentioned stretching apparatus 90 will be described with reference to Figs. 22 and 23.

Views in the upper part of Fig. 24 show that the laminate 70' is processed while being sandwiched between the pair of toothed stretching rolls 91 and 92 of the stretching apparatus 90. The laminate 70' being subjected to roll stretching naturally has an irregular shape, and the stretchable sheet 70 further has a corrugated shape as a whole in some cases. However, for the purpose of convenience, (B) and (C) of Fig. 24 show the irregular shape and the corrugated shape that are elongated into a planar shape, without extending the elastic filaments 871.

[0112] As shown in the lower view of (A) of Fig. 24, in the laminate 70' before roll stretching is performed, the fibers of the unprocessed first non-woven fabric 85' and the unprocessed second non-woven fabric 86' are welded to the elastic filaments 87a at the interface. The laminate 70' in this stage does not have stretch property. The elastic filaments 87a extend along the conveying direction of the laminate 70'. The conveying direction corresponds to the Y-axis direction of the stretchable sheet 70.

[0113] Next, as shown in (B) of Fig. 24, the laminate 70' is meshed between the rotated toothed stretching rolls 91 and 92 and is thus partially extended. Specifically, when the teeth 79 and the teeth 80 are meshed with each other, a region of the laminate 70' that is positioned between a top land 88 of the tooth 79 and a top land 89 of the tooth 80 adjacent to the tooth 79 is extended, and regions that abut on the top land 88 of the tooth 79 and the top land 89 of the tooth 80 are scarcely extended.

In the extended region of the laminate 70', the elastic filaments 87a are extended, and the fibers constituting the unprocessed first non-woven fabric 85' and the unprocessed second non-woven fabric 86' are stretched and plastically deformed to be extended. Further, part of the fibers welded to the elastic filaments 87a are peeled from the elastic filaments 87a.

Meanwhile, in the region in which the laminate 70' is not extended, the elastic filaments 87a are not extended, and the fibers constituting the unprocessed first non-woven fabric 85' and the unprocessed second non-woven fabric 86' are not plastically deformed. Further, peeling of the fibers from the elastic filaments 87a scarcely occurs.

[0114] Subsequently, when the extension of the elastic filaments 87a by the roll stretching is released, as shown in (C) of Fig. 24, the fibers keeping extended due to plastic deformation by roll stretching and the fibers peeled from the elastic filaments 87a protrude in a loop shape so as to be away from the elastic filaments 87a in association with the contraction of the elastic filaments 87a, thus forming the projections 74 and the projections 71. The projections 74 and the projections 71, i.e., the protruding fibers of the non-woven fabrics, are room for extension when the stretchable sheet 70 is extended. Such regions in which the plastically deformed fibers of the non-woven fabrics are disposed are the stretchable portions 70a of the stretchable sheet 70.

Meanwhile, the non-woven fabrics in the regions in which, at the time of roll stretching, the elastic filaments 87a are not extended and the fibers are not plastically deformed and are kept welded to the elastic filaments 87a form the flat portions 75 and 72. Such regions in which the fibers of the non-woven fabrics, which are not plastically deformed, are disposed are the connection portions 70b of the stretchable sheet 70.

[0115] In such a manner, when the teeth 79 and the teeth are meshed with each other at the time of roll stretching, the regions of the laminate 70' that abut on the top land 88 of the tooth 79 and the top land 89 of the tooth 80 are the connection portions 70b, and the region of the laminate 70' that is positioned between the top land 88 of the tooth 79 and the top land 89 of the tooth 80 adjacent to the tooth 79 is the stretchable portion 70a. The stretchable portions 70a and the connection portions 70b are alternately formed in the Y-axis direction.

[0116] In the roll stretching of this embodiment, the small depth portion 77a of the toothed stretching roll 91 and the small depth portions 78 of the toothed stretching roll 92 abut on the center portion obtained when the laminate 70' is equally divided into three in the X-axis direction orthogonal to the conveying direction, and the large depth portions 77b of the toothed stretching roll 91 and the large depth portions 78b of the toothed stretching roll 92 abut on both side portions in the X-axis direction.

In this embodiment, the amount of mesh between the small depth portions 77a and 78a was set to 2 mm, and the amount of mesh between the large depth portions 77b and 78b was set to 3 mm. Thus, a draw ratio of the region, in the center portion in the X-axis direction, which is stretched by the mesh between the small depth portions 77a and 78a, is lower than that in the regions of both the side portions in the X-axis direction, which are stretched by the mesh between the large depth portions 77b and 78b.

[0117] In this production method, the stretchable sheet 70 can be produced without using adhesives. Thus, in the stretchable sheet 70, the touch feeling of the first nonwoven fabric 85 and the second non-woven fabric 86 can be kept soft due to the adhesives. Further, in the stretchable sheet 70, the elastic filaments 87a are contained by the first non-woven fabric 85 and the second non-woven fabric 86.

The touch feeling of the first non-woven fabric 85 and the second non-woven fabric 86 is not also impaired by the elastic filaments 87a, and the original soft touch feeling of the non-woven fabrics is obtained as it is.

[0118] [Configuration of Disposable Diaper] Fig. 25 is a perspective view of a disposable diaper 30 (hereinafter, referred to as diaper 30) according to an embodiment of the present invention, in which the above-mentioned stretchable sheet 70 including the regions having mutually different contraction stresses is applied to an exterior member 39. The diaper 30 is a pant-type absorbent article for catching the excreta of a baby or infant being a wearer without leaking it.

The diaper 30 includes the exterior member 39 and an absorbent member 9. The exterior member 39 constitutes an exterior of the diaper 30. The absorbent member 9 is held inside of the exterior member 39. In other words, the exterior member 39 is disposed on the surface side on the outside of the absorbent member 9, which faces to the side opposite to the skin side of a wearer when the disposable diaper is worn.

Hereinafter, the inside in each configuration indicates a side, of the diaper, positioned on the skin side of a wearer when the diaper is worn, and the outside indicates the opposite side of the skin side of the wearer.

[0119] The absorbent member 9 is configured to be capable of catching excreta and also absorbing liquid included in the excreta. The absorbent member 9 is formed into a belt-like shape and is disposed in a wide range in the exterior member 39 from a crotch portion 40 to an abdominal portion 34a and a dorsal portion 34b of a waist portion 34.

[0120] The exterior member 39 includes the waist portion 34 and the crotch portion 40 that are continuously formed. The waist portion 34 forms a waist opening 7 and is disposed around the trunk of the wearer. The waist portion 34 includes a stretchable member that is stretchable over the circumferential direction of the trunk so as to be fitted around the trunk of the wearer. The crotch portion 40 is positioned on the lower side of the waist portion 34 in Fig. and disposed in the crotch of the wearer.

The waist portion 34 includes the abdominal portion 34a disposed on the front side when the diaper is worn, and the dorsal portion 34b disposed on the rear side. The abdominal portion 34a and the dorsal portion 34b are joined in side seal portions 18 provided to both ends in a width direction orthogonal to a front-back direction by, for example, heat sealing or ultrasonic sealing. Thus, the waist portion 34 has a tubular shape and forms the waist opening 7 between the abdominal portion 34a and the dorsal portion 34b.

The crotch portion 40 is positioned between the abdominal portion 34a and the dorsal portion 34b. The crotch portion 40 connects the abdominal portion 34a and the dorsal portion 34b to each other so as to form a pair of leg openings 14, into which the legs of the wearer are inserted, on both sides of the crotch portion 40 in the width direction. The crotch portion 40 includes leg gathers 19 that are disposed along the leg openings 14 and include rubber threads 19a.

[0121] The diaper 30 and the exterior member 39 shown in Figs. 26 and 27 are in a state where the side seal portions 18 are torn off to separate the abdominal portion 34a and the dorsal portion 34b from each other, and the exterior member 39 and the absorbent member 9 are further extended along the X-Y plane from the state shown in Fig. 25.

Fig. 27 is a plan view showing an unfolded state of the exterior member 39 of the diaper 30 of Fig. 25, showing positions of high contraction stress regions P1 and low contraction stress regions P2. Fig. 27 corresponds to a view of the exterior member 39 seen from the outside, in which a first sheet 44 to be described later is positioned on the near side. Stretchable regions of the exterior member 39 are shown in a dot pattern, and the degree of magnitude of the contraction stress in each region is expressed by the density of the dot pattern. As the contraction stress increases, the density of the dot pattern increases, and as the contraction stress decreases, the density of the dot pattern decreases.

[0122] The exterior member 39 includes a stretchable sheet.

The exterior member 39 of this embodiment includes a composite sheet 60 that is a stretchable member, in which the first sheet 44 and a second sheet 12 that is a base sheet are attached to each other with a bonding layer 13. The first sheet 44 is constituted using the stretchable sheet 70 having a plurality of regions having mutually different contraction stresses described above. Regions corresponding to the abdominal portion 34a and the dorsal portion 34b of the first sheet 44 are stretchable in the circumferential direction of the trunk.

The first sheet 44 is a stretchable non-woven fabric made of a non-woven fabric containing an elastic resin layer. The second sheet 12 is a non-stretchable sheet made of a non-stretchable non-woven fabric disposed to face the first sheet 44. The bonding layer 13 bonds the first sheet 44 and the second sheet 12 to each other. In this embodiment, the second sheet 12 is provided to face the inside of the first sheet 44, and the first sheet 44 is positioned on an outer surface 39a side of the exterior member 39.

In the diaper 30 shown in Figs. 25 and 26 and the exterior member 39 shown in Fig. 27, the X-axis direction corresponds to the front-back direction, the Y-axis direction corresponds to the width direction, and the Z-axis direction corresponds to the thickness direction. The circumferential direction of the trunk in the abdominal portion 34a and the dorsal portion 34b of the waist portion 34 in Fig. 25 corresponds to the width direction Y in Figs. 26 and 27. Further, the stretching direction Y of the stretchable sheet 70 described above and the width direction Y of the diaper 30 are the same direction.

Hereinafter, in the description for the waist oortion 34, an up-down direction will be described in some cases. The up-down direction corresponds to the up-down direction of the diaper 30 when a wearer standing up wears the diaper 30. The front-back direction and the up-down direction are the same direction.

[0123] The waist portion 34 of the exterior member 39 has stretch property in the circumferential direction of the trunk. As shown in Fig. 27, in the waist portion 34 of the first sheet 44 constituting the exterior member 39 that needs stretch property in the circumferential direction of the trunk, the abdominal portion 34a (dorsal portion 34b) includes a first region 31a (first region 31b) and two second regions 32a (second regions 32b), which have mutually different contraction stresses.

In the abdominal portion 34a (dorsal portion 34b), which is equally divided into three regions in the up-down direction orthogonal to the circumferential direction of the trunk, the first region 31a (first region 31b) is oositioned in the center region positioned at the center of those regions. In this embodiment, the second regions 32a (second regions 32b) are positioned in both of a pair of end regions positioned to face each other in the up-down direction via the center region. It should be noted that, in this embodiment, high projections are disposed on both the pair of end regions to be the second regions, but the high projections may be provided to at least one of the end regions.

The first region 31 (second region 32) includes the first region 31a of the abdominal portion (second regions 32a of abdominal portion) and the first region 31b of the dorsal portion (second regions 32b of dorsal portion), and unless otherwise distinguished therebetween, both of them are referred to as the first region 31 (second region 32).

[0124] The first region 31 and the second region 32 have mutually different contraction stresses. The first region 31 is a high contraction stress region P1, and the second region 32 is a low contraction stress region P2. The first region 31 includes low projections 71a and 74a, and the second region 32 includes high projections 71b and 74b. The contraction stress is relatively high in the first region 31 and low in the second region 32. Further, the width dimension (the length in the Y-axis direction) of the low contraction stress region P2 and the width dimension of the high contraction stress region P1 are almost equal to each other.

In other words, the waist portion 34 is configured to have different forces to return to the original state by contraction (contraction stress) in each region when the first region 31 and the second region 32 are extended at the same extension rate. Thus, when the waist portion 34 is extended at the same extension rate, different tightening pressures for each of the regions are to be applied to the wearer.

In this embodiment, the upper side of the waist portion 34 (near the waist opening 7) and the lower side thereof (region near the crotch portion 40 of the waist portion 34) are configured to have a lower contraction stress, that is, a smaller tightening pressure than those of the center portion of the waist portion 34 in the up-down direction.

[0125] (Structure of Exterior Member) Each configuration of the exterior member 39 will be described with reference to Figs. 26 and 27.

The first sheet 44 is a seamlessly continuous, stretchable sheet that is continuously formed from the abdominal portion 34a to the dorsal portion 34b through the crotch portion 40.

In the composite sheet 60, the first sheet 44 is stretchable by itself due to the elastic force of the elastic filaments 87a, and the composite sheet 60 functions as a stretchable sheet. Thus, in the composite sheet 60, the waist portion 34 of the exterior member 39 can be extended and contracted in the circumferential direction of the trunk in Fig. 25 by using the stretch property of the first sheet 44. Therefore, the composite sheet 60 can have a configuration including no elastic member such as a rubber thread between the first sheet 44 and the second sheet 12.

[0126] The bonding layer 13 includes a plurality of bonding portions 21 disposed between the first sheet 44 and the second sheet 12. The bonding layer 13 is disposed over the first region 31a (first region 31b) and the two second regions 32a (second regions 32b) of the abdominal portion 34a (dorsal portion 34b). The plurality of bonding portions 21 continuously extend in the up-down direction and are intermittently arranged in the circumferential direction of the trunk.

The bonding layer 13 is typically formed of an adhesive.

For the adhesive to form the bonding layer 13, a hot-melt adhesive is used. It should be noted that the bonding layer 13 can be formed of various adhesives such as a thermoplastic adhesive and a reactive adhesive, other than the hot-melt adhesive.

[0127] The second sheet 12, which is made of a non-stretchable non-woven fabric and constitute part of the composite sheet 60, can be formed of an arbitrary non-stretchable sheet that is difficult to extend and contract in the Y-axis direction. For the non-stretchable sheet constituting the second sheet 12, for example, a non-woven fabric, a woven fabric, paper, and the like can be used. As an example, the second sheet 12 can be formed of a non-woven fabric using a fiber similar to that of the first non-woven fabric 85 and the second non-woven fabric 86 of the first sheet 44 in order to obtain a touch feeling like the first sheet 44.

[0128] The diaper 30 is produced as follows.

The exterior member 39 is formed by disposing the bonding layer 13 on the first sheet 44 extended at a constant extension rate and attaching the second sheet 12 thereto.

Here, attaching at a constant extension rate refers to attaching the second sheet 12 in a state where the high contraction stress regions P1 and the low contraction stress regions P2 of the first sheet 44 are extended at the same extension rate.

Next, after the absorbent member 9 is superimposed on the inside of the exterior member 39 in the extended state and both of them are bonded and fixed to each other, the abdominal portion 34a and the dorsal portion 34b are superimposed on each other while maintaining the extended state, and corresponding side edge portions are joined to from the side seal portions 18. Thus, a pull-on diaper 30 is produced.

[0129] In the diaper 30 of this embodiment, the stretchable sheet 70 is applied as the first sheet 44 for providing stretch property to the composite sheet 60 constituting the abdominal portion 34a and the dorsal portion 34b. Thus, the disposable diaper 30 having a high body following ability and good fitting property around the trunk can be obtained.

Moreover, in the diaper 30 of this embodiment, as described above, the stretchable sheet 70 that is a single seamless member and includes regions having mutually different contraction stresses in the X-axis direction is used as the first sheet 44. This can provide the diaper 30 being seamless in the entire abdominal portion 34a and the entire dorsal portion 34b and having an appearance and the sense of touch like pants as underwear having a uniform texture like a fabric.

[0130] Further, in the diaper 30 of this embodiment, the center portion of the waist portion 34 in the up-down direction is configured to have a higher contraction stress and a higher tightening pressure when the disposable diaper is worn, than those of the upper and lower sides of the waist portion 34, which makes it possible to effectively prevent the diaper 30 from slipping down during wearing.

A wearer, particularly an infant, has a bulging abdominal region as a physical feature. If a tightening force for a portion, of the waist portion, which is to abut on the bulging abdominal region, is increased, because of the high tightening force, the waist portion of the disposable diaper is gradually squeezed and is likely to slip down to a slim part of the abdominal region.

In this embodiment, the first region 31 having a high contraction stress is provided to the center portion of the waist portion 34 in the up-down direction such that a region of the waist portion 34 having a relatively high tightening force abuts on the slim part around the trunk, which makes it possible to effectively prevent the disposable diaper from slipping down during wearing. In order to effectively prevent such slipping down during wearing, the relationship of the contraction stress between the center portion of the waist portion 34 in the up-down direction and the upper and lower sides of the waist portion 34 is preferably set to the following ranges.

[0131] Hereinafter, description will be given on a

contraction stress value, a dimension of each configuration, and the like that are suitable for a case where the stretchable sheet 70 is used for an exterior member of an absorbent article such as a diaper. The numerical values to be described here are examples, and a dimension and the like of each configuration of the stretchable sheet may be appropriately set so as to have a contraction stress distribution suitable for an article using the stretchable sheet.

[Contraction Stress Value] (Contraction Stress Value in Stretchable Sheet) Assuming that the stretchable sheet of the present invention is used for an exterior member of an absorbent article or the like, a contraction stress at the degree of elongation 50% of the low contraction stress regions P2 and the high contraction stress regions P1 in the stretchable sheet is set to the upper limit or less, which will be described later, to avoid leaving a depression on the skin of the wearer, and is set to the lower limit or less, which will be described later, to keep a proper wearing state.

Here, the exterior member may be made of a single stretchable sheet or may be made of a composite sheet in which a stretchable sheet and a non-stretchable sheet are laminated as in the diaper 30 described above. In any configuration of those cases, setting the contraction stress value of the stretchable sheet to fall within the ranges to be described later can provide a contraction stress distribution suitable for the exterior member.

[0132] Specifically, the contraction stress at the degree of elongation 50% of the low contraction stress regions P2 in which the high projections 74b (71b) are disposed is preferably 1 cN/mm or more and more preferably 1.5 cN/mm or more, and further, preferably 3 cN/mm or less and more preferably 2.5 cN/mm or less. Such a contraction stress is preferably 1 cN/mm or more and 3 cN/mm or less, and more preferably 1.5 cN/m or more and 2.5 cN/mm or less. In this embodiment, such a contraction stress is 2 cN/mm.

The contraction stress at the degree of elongation 100% of the low contraction stress regions P2 in which the high projections 74b (71b) are disposed is preferably 2 cN/mm or more and more preferably 2.5 cN/mm or more, and further, preferably 4 cN/mm or less, and more preferably 3.5 cN/mm or less. Such a contraction stress is preferably 2 cN/mm or more and 4 cN/mm or less, and more preferably 2.5 sN/mm or more and 3.5 cN/mm or less. In this embodiment, such a contraction stress is 3 cN/mm.

[0133] The contraction stress at the degree of elongation 50_ of the high contraction stress regions P1 in which the low projections 74a (71a) are disposed is preferably 2 cN/mm or more and more preferably 2.5 cN/mm or more, and further, preferably 4 cN/mm or less and more preferably 3.5 cN/mm or less. Such a contraction stress is preferably 2 cN/mm or more and 4 cN/mm or less, and more preferably 2.5 sN/m or more and 3.5 cN/mm or less. In this embodiment, such a contraction stress is 4 cN/mm.

The contraction stress at the degree of elongation 100, of the high contraction stress regions P1 in which the low projections 74a (71a) are disposed is preferably 40 cN/mm or more and more preferably 50 cN/mm or more, and further, preferably 90 cN/mm or less, and more preferably 80 cN/mm or less. Such a contraction stress is preferably 40 cN/mm or more and 90 cN/mm or less, and more preferably 50 cN/mm or more and 80 cN/mm or less. In this embodiment, such a contraction stress is 67 cN/mm.

[0134] In such a manner, in the stretchable sheet 70, a contraction stress per unit length of the low contraction stress region P2 in the Y-axis direction is lower than that of the high contraction stress region P1.

[0135] In this embodiment, the elastic filaments 87a are arranged at regular intervals in the X-axis direction in each region of the high contraction stress regions P1 and the low contraction stress regions P2. Further, the thickness and the density of the elastic filaments 87a are the same. Thus, in the stretchable sheet 70, the difference in contraction stress due to the difference in height between the high projections 74b (71b) and the low projections 74a (71a) is effectively generated.

For example, it is unnecessary to use different elastic filaments as follows: elastic filaments having a high elastic stress are disposed to provide high contraction stress regions, and elastic filaments having a low elastic stress are disposed to provide low contraction stress regions.

So, the stretchable sheet 70 is preferably configured to include high projections and low projections and configured such that the contraction stresses at the degrees of elongation 50% and 100% of the high contraction stress regions P1 and the low contraction stress regions P2 fall within the ranges of the numerical values described above.

[0136] Hereinafter, a method of creating samples to be used to measure the contraction stresses of the stretchable sheet and a method of measuring the samples will be described. (Method of Creating Samples for Measuring Contraction Stresses of Stretchable Sheet) In an absorbent article including the stretchable sheet as part of its configuration, in the case where only a portion made of elastic filaments and non-woven fabrics directly joined thereto, i.e., a minimum configuration unit of the stretchable sheet, is exposed, only the exposed portion is cut out with scissors or a cutter to be obtained. In the case where the above-mentioned exposed portion does not exist and the stretchable sheet is joined to another constituent with an adhesive, after the absorbent article is immersed in acetone, toluene, or butyl acetate for 24 hours, the above-mentioned minimum configuration unit is _picked up on a metal tray and subjected to air drying for 96 hours within a fume hood, to obtain the stretchable sheet. In the case where the above-mentioned exposed portion does not exist and the stretchable sheet is joined to another constituent by thermal fusion or the like, the stretchable sheet is obtained by being carefully taken off manually so as not to be damaged.

The stretchable sheet obtained by the above-mentioned technique is cut along straight lines parallel to the stretching direction (corresponding to the Y-axis direction) and further cut along straight lines parallel to a direction orthogonal to the stretching direction (corresponding to the X-axis direction), to cut out rectangular samples from the respective regions of the high contraction stress region P1 and the low contraction stress region P2. The samples are cut out to have a belt-like shape and a size of 70 mm along the Y-axis direction and 50 mm along X-axis direction in a natural state after cutting. It should be noted that if it is difficult to form a sample having a 70 mm in the width direction, the length is appropriately changed.

(Measurement Method) Both sides of the cut-out sample of each region in the length direction (corresponding to the Y-axis direction) are fixed between a pair of chucks of a Tensilon tensile tester ("Autograph AG-X" manufactured by Shimadzu Corporation). The chuck part is assumed to have a length of 20 mm in the tensile direction and a length of 60 mm in a direction orthogonal to the tensile direction. To fix the sample, a portion with a 10-mm width from the end edge in each of both ends of the sample in the length direction is nipped with the chuck so as to be included in the chuck part and is fixed at an air pressure of at least 1 MPa. A chuck interval is set to 50 mm, and the sample is fixed in a natural state. It should be noted that the chuck interval is appropriately adjusted in accordance with the length of the sample piece.

The sample is then extended at 300 mm/min. Tensile loads (cN) per unit length (1 mm) at the points when the length of the sample (distance between chucks) is 150% and 200% of the length in a natural state are respectively assumed as a contraction stress at the degree of elongation 50% and a contraction stress at the degree of elongation 100%.

[0137] (Contraction Stress Value in Exterior Member) In the case where the exterior member 39 of the diaper is constituted using the composite sheet 60, preferable contraction stress values in the composite sheet 60 are as follows.

The contraction stress of the high contraction stress region P1 (first region 31) is preferably 1.4 cN/mm or more and more preferably 2 cN/mm or more, and further, oreferably 5 cN/mm or less. Such a contraction stress is preferably 1.4 cN/mm or more and 5 cN/mm or less, and more preferably 2 cN/mm or more and 5 cN/mm or less.

The contraction stress of the second region 32 is preferably 0.1 cN/mm or more and more preferably 0.5 cN/mm or more, and further, preferably 3 cl\l/mm or less and more preferably 2.5 cN/mm or less. Such a contraction stress is preferably 0.1 cN/mm or more and 3 cN/mm or less, and more preferably 0.5 cN/mm or more and 2.5 cN/mm or less.

The contraction stress of the first region 31 is preferably 1.2 times or more and more preferably 1.4 times or more the contraction stress of the second region 32, and further, preferably 3 times or less and more preferably 2.5 times or less the contraction stress of the second region 32.

[0138] Hereinafter, a method of creating samples to be used to measure the contraction stresses of the exterior member and a method of measuring the samples will be described.

(Method of Creating Samples for Measuring Contraction Stresses of Exterior Member) The side seal portions 18 of the disposable diaper 30 are peeled, and the exterior member 39 is extended at the same ratio in each of the first region 31 and the second region 32 of the exterior member 39 to be unfolded and spread on the plane. Each of the abdominal portion 34a and the dorsal portion 34b is cut along straight lines parallel to the width direction and further cut along straight lines parallel to the front-back direction, to cut out rectangular samples from the respective regions of the first region 31 and the second region 32. The samples are cut out of, in plan view, a region of the exterior member 39 other than the region facing the absorbent member 9 and a region of the exterior member 39 outside of the region sandwiched by the extended lines of the pair of both side edge portions of the absorbent member 9 that define the width direction of the absorbent member 9. The samples are cut out to have a size of 70 mm along the Y-axis direction and 50 mm along the X-axis direction in a natural state after cutting, as with the case of creating the samples of the stretchable sheet. (Measurement Method) As in the measurement method for the stretchable sheet, the cut-out sample of each region is fixed to the Tensilon tensile tester described above. Next, the sample is extended at 300 ram/min. After the sample is extended until the length of the sample (distance between chucks) is 185% of the length in a natural state, when the sample is contracted to the length of 140%, a tensile load (cN) per unit length (1 mm) in the width direction is assumed as contraction stress. It should be noted that setting 140% as an index is for reproducing the extended state of the sample when the pull-on disposable diaper 30 is worn.

[0139] [Dimension of Each Configuration of Stretchable Sheet]

Description will be given on examples of specific

dimensions of the respective configurations in the case where the stretchable sheet 70 has the contraction stress values described above.

First, the positions indicated by the respective configurations will be described with reference to Figs. 17 and 20.

As shown in Fig. 20, a height h of the projection 74 (71) represents a distance from the center of the elastic filament 87a in the Z-axis direction to the top of the projection 74 (71).

A width w of the projection 74 (71), that is, the length thereof in the Y-axis direction represents a distance between the boundaries with the flat portions 75 (72) positioned on both sides of each projection 74 (71).

A distance c between the projections 74 (71) represents a distance between the tops of the projections 74 (71) positioned adjacently to each other on the same surface side of the stretchable sheet 70.

A width d of the flat portion 75 (72), that is, the length thereof in the Y-axis direction represents a distance between the boundaries with the projections 74 (71) positioned on both sides of each flat portion 75 (72).

A wave width e represents a distance between the top portion 81 and the trough portion 82 of the stretchable sheet 70 having a corrugated shape and corresponds to the thickness of the stretchable sheet 70 having a corrugated shape as shown in (B) of Fig. 20.

As shown in Fig. 17, an arrangement interval f between the elastic filaments 87a represents a center distance between the adjacent elastic filaments 87a.

[0140] (Dimension of Each Configuration) A two-point threshold of human fingertips is known as being approximately 2 mm. Because of this, in order to obtain uniformity on a surface of the stretchable sheet in terms of the sense of touch, each of the above-mentioned height h, width w, distance c, width d, wave width e, and interval f is preferably set to 2 mm or less.

More specifically, the height h of the high projection 74b (71b) positioned in the low contraction stress region P2 is preferably 750 pm or more and 950 pm or less. In this embodiment, the height h of the high projection 74b (71b) is 841 pm.

The width w of the high projection 74b (71b) is preferably 900 pm or more and 1100 pm or less. In this embodiment, the width w of the high projection 74b (715) is 998 pm.

The distance c between the high projections 74b (71b), that is, the arrangement interval between the projections 74 (71) in the low contraction stress region P2 is preferably 1400 pm or more and 1600 pm or less. In this embodiment, the distance c between the high projections 74b (71b) is 1526 pm.

The width d of the flat portion 75 (72) in the low contraction stress region P2 is preferably 500 pm or more and 750 pm or less. In this embodiment, the width d of the flat portion 75 (72) in the low contraction stress region P2 is 620 pm.

The wave width e in the low contraction stress region P2 is preferably 350 pm or more and 600 pm or less. In this embodiment, the wave width e in the low contraction stress region P2 is 481 pm.

[0141] The height h of the low projection 74a (71a) positioned in the high contraction stress region P1 is preferably 450 pm or more and 650 pm or less. In this embodiment, the height h of the low projection 74a (71a) is 544 pm.

The width w of the low projection 74a (71a) is preferably 850 pm or more and 1050 pm or less. In this embodiment, the width w of the low projection 74a (71a) is 957 pm.

The distance c between the low projections 74a (71a), that is, the arrangement interval between the projections 74 (71) in the high contraction stress region P1 is preferably 1500 pm or more and 1700 pm or less. In this embodiment, the distance c between the low projections 74a (71a) is 1602 pm. The width d of the flat portion 75 (72) in the high contraction stress region P1 is preferably 500 pm or more and 750 pm or less. In this embodiment, the width d of the flat portion 75 (72) is 636 pm.

The wave width e in the high contraction stress region P1 is preferably 350 pm or more and 600 pm or less. In this embodiment, the wave width e in the high contraction stress region P1 is 491 pm.

The arrangement interval f between the elastic filaments 87a is preferably 0.5 mm or more and 2 mm or less. In this embodiment, the arrangement interval f between the elastic filaments 87a is 1 mm.

[0142] In the low projection 74a (71a) and the high projection 74b (71b) disposed on the same surface side of the stretchable sheet 70, the height of the low projection 74a (71a) is preferably 0.5 times or more and more preferably 0.6 times or more the height of the high projection 74b (71b), and further, preferably 0.8 times or less and more preferably 0.7 times or less the height of the high projection 74b (71h). The height of the low projection 74a (71a) is preferably 0.5 times or more and 0.8 times or less, and more preferably 0.6 times or more and 0.7 times or less the height of the high projection 74b (71b). In this embodiment, the height of the low projection 74a (71a) is approximately 0.65 times the height of the high projection 74b (71b).

[0143] In this embodiment, the distance c between the high projections 74b (71b) in the low contraction stress region P2 and the distance c between the low projections 74a (71a) in the high contraction stress region Fl are almost the same.

Further, since the width w of the high projection 74b (71b) and the width w of the low projection 74a (71a) are almost the same, the widths in the stretching direction in the high contraction stress region P1 and the low contraction stress region P2 of the stretchable sheet 70 are almost the same in a natural state. Such a stretchable sheet 70 has an appearance having a sense of unity, in which the boundary between the high contraction stress region P1 and the low contraction stress region P2 is difficult to recognize.

Irrespective of such an appearance having a sense of unity, the stretchable sheet 70 is a sheet capable of generating the function of providing a different contraction stress for each of the regions at the time of extension.

Here, in this specification of the subject application, "almost the same" means that one value is in the range of 90% to 110% of another value.

In the stretchable sheet 70, in each region of the high contraction stress region P1 and the low contraction stress region P2 on each surface of the stretchable sheet 70 in a natural state, a ratio (h/c) of the height h of the projection to the distance c between projections desirably has a value of 1 or less. Setting the ratio to the upper limit or less allows the stretchable sheet 70 to have an appearance having a sense of unity in the in-plane direction of the non-woven fabrics and allows the hubbly sheet surface to be smoothed as a whole, which makes it difficult to cause material fracture due to being hooked.

[0144] (Method of Measuring Dimension of Each Configuration of Stretchable Sheet) In the stretchable sheet 70 at the time of non-extension described above, the height and width of the projection, the distance between the projections, the dimension of the width of the flat portion, the wave width, the arrangement interval between the elastic filaments 87a, and the size of the thermally-fused-portion-non-existence region 65 to be described later are measured as follows.

Five pieces of samples are obtained by pressing the edge of a single-edged razor blade for trimming (3-Facet.009"/. 23 mm), which is manufactured by Nisshin EM Co., Ltd., to the stretchable sheet 70 at a strain rate of at least 100 Hz to cut the stretchable sheet 70. The cross section of each of the cut samples can be observed using a microscope (VHX-1000 manufactured by KEYENCE CORPORATION) by a factor of 20 to 100, and each dimension can be measured. An average of the measured results of the five samples is calculated as a dimension.

[0145] [Dimension of Thermally-fused-portion-non-existence Region] The length of the thermally-fused-portion-non-existence region 65 in the Y-axis direction in the stretchable sheet 70 is preferably 0.2 mm or more and more preferably 0.4 mm or more, and further, preferably 1.4 mm or less and more preferably 1.2 mm or less. The length described above is preferably 0.2 mm or more and 1.4 mm or less, and more preferably 0.4 mm or more and 1.2 mm or less. In this embodiment, the length described above is 0.79 mm.

The length of the thermally-fused-portion-non-existence region 65 in the X-axis direction is preferably 1.2 mm or more and more preferably 1.4 mm or more, and further, preferably 2.4 mm or less and more preferably 2.2 mm or less. The length described above is preferably 1.2 mm or more and 2.4 mm or less, and more preferably 1.4 mm or more and 2.2 mm or less. In this embodiment, the length described above is 1.84 mm.

The length of the thermally-fused-portion-non-existence region 65 in the X-axis direction is preferably 1.5 times or more and more preferably 1.8 times or more the length thereof in the stretching direction Y, and further, preferably 3 times or less and more preferably 2.8 times or less the length thereof in the stretching direction Y. The length described above is preferably 1.5 times or more and 3 times or less, and more preferably 1.8 times or more and 2.8 times or less the length thereof in the stretching direction Y. In this embodiment, the length described above is approximately 2.3 times the length in the stretching direction Y. [0146] [Residual Strain of Fiber of Non-woven Fabric] In at least one layer of the non-woven fabrics 85 and 86 constituting the stretchable sheet 70, it is desirable that the residual strain, which is obtained after application of 100% extension, of the fiber constituting the non-woven fabric is preferably 70% or less and more preferably 65% or less, and further preferably 50',; or more and more Preferably 55(:, or more. The residual strain described above is preferably SO', or more and 707. or less, and more preferably 55% or more, and is preferably 50% or more and 70% or less, and more preferably 559, or more and 65', or less.

At the time of extension, in the boundary 69, an oblique shear stress acts on the boundary 69. In order to make it difficult to cause material damage at the time of extension, the first non-woven fabric 85 or the second non-woven fabric 86 is desirably a sheet having elasticity capable of tolerating this shear stress.

In the case where the first non-woven fabric 85 and the second non-woven fabric 86 are formed using a fiber with a large elastic behavior amount in which the residual strain has the above-mentioned upper limit or less, the shear stress can be tolerated in the vicinity of the boundary 69 between the high contraction stress region P1 and the low contraction stress region P2, and the material damage can be less likely to occur at the time of extension.

Thus, the residual strain, which is obtained after application of 100% extension, of the fiber constituting at least one layer of the first non-woven fabric 85 and the second non-woven fabric 86 that are to be the base material more preferably has the above-mentioned upper limit or less. Such a non-woven fabric having a small residual strain can be obtained by, for example, a spunbonding method using a resin containing isotactic polypropylene and a propylene-ethylene-a-olefin copolymer mixed with each other.

[0147] Here, a combination of forces is assumed in the case where the high contraction stress region P1 and the low contraction stress region P2 are each provided with an imaginary square having the same size and using the boundary 69 as a side thereof, and the imaginary squares of the respective regions are arranged such that the diagonal lines of them are on one straight line.

In the case where a shear strain along the stretching direction is provided to the stretchable sheet 70, the amount of extension caused in the diagonal direction of the imaginary square provided in the vicinity of the boundary 69 is approximately 1.41 times the amount of extension generated in the direction of a side of the square along the stretching direction. Therefore, an inelastic behavior amount of the fiber constituting the non-woven fabric is tolerated, at the maximum, up to approximately 70% obtained by dividing the length of the side of the imaginary square by the length of the diagonal line of the imaginary square and then multiplying the obtained value by 100.

Therefore, in at least one layer of the non-woven fabrics 85 and 86, it is desirable that the residual strain, which is obtained after application of 100% extension, of the fiber constituting the non-woven fabric is preferably 70% or less. This makes it difficult to cause the material damage.

[0148] (Method of Measuring Residual Strain of Fiber of Non-woven Fabric) The residual strain of the fiber constituting the non-woven fabrics 85 and 86 of the stretchable sheet 70 is measured as follows.

In a region including no thermally-fused portion in the flat portion of the stretchable sheet 70, a razor blade is pressed to the stretchable sheet in a manner similar to the above-mentioned method of measuring the dimension of each configuration, and a maximum rectangle in the range excluding the thermally-fused portion is cut out such that two of the four sides are parallel to the X-axis direction or the Y-axis direction. In the cut-out pieces of the stretchable sheet, the first non-woven fabric 85 and the second non-woven fabric 86 are pulled with tweezers to be peeled from the elastic filaments 87a and are then separated from each other. In the stretchable sheet 70, the first non-woven fabric 85 and the second non-woven fabric 86 are welded to the elastic filaments 87a at the interface, and thus they can be separated in such a manner.

Next, in the non-woven fabric pieces of the peeled and separated non-woven fabrics 85 and 86, all fibers are pulled out with the tweezers from the cross section of the stretchable sheet along the X-axis direction, to obtain a fiber group. One fiber is taken out of the fiber group, and both sides of the fiber are fixed between a pair of chucks of the Tensilon tensile tester described above. To fix the sample, a portion having 20% of the fiber length from the end edge in each of both ends of the sample in the length direction is nipped with the chuck to be fixed. A chuck interval is set to 60% of the fiber length. It should be noted that the chuck interval is appropriately adjusted in accordance with the length of the sample piece. After the sample is extended at 50 ram/min and at the extension rate of 100% in the length direction of the sample, the extended state is gradually released for contraction, to obtain a strain (%) when the tensile stress reaches 0.1 cN/mm.

Further, the sample is extended at the rate of 50 mm/min, and a degree of elongation obtained when the extension of the sample stops is obtained as a maximum degree of elongation (%). The residual strain (%) is obtained by dividing the strain, which is obtained when the tensile stress reaches 0.1 cN/mm, by the maximum degree of elongation and by multiplying the obtained value by 100. This measurement is performed on all the fiber groups described above to obtain residual strains, and an average value thereof is assumed as a residual strain of the fiber constituting the non-woven fabric.

[0149] [Residual Strain of Elastic Filaments] Further, in the case where the stretchable sheet 70 is applied to the exterior member 39 of the diaper 30, it is desirable that the elastic filaments 87a have a residual strain that is 60% or less after application of 100% extension for six hours under the temperature condition of 40°C. Further, the residual strain is preferably 50% or more.

Here, 40°C is for providing a temperature close to a body temperature of a wearer of the disposable diaper when the stretchable sheet 70 is applied to the exterior member of the disposable diaper, and is set to a temperature close to an actual use environment.

In such a manner, with the elastic filaments 87a having a small degree of stress relaxation, i.e., having a residual strain that is 60T-or less after application of 100T-extension for six hours under the temperature condition of 40°C, the stretch property of the stretchable sheet 70 can be maintained. Thus, a comfortable wearing feeling can be provided to the wearer.

It should be noted that in the case where only the elasticity of the elastic filaments 87a is focused on, the lower limit of the residual strain is not limited.

[0150] (Method of Measuring Residual Strain of Elastic Filaments) The residual strain of the elastic filaments described above is measured as follows.

In a manner similar to the above-mentioned method of measuring the residual strain of the fiber of the non-woven fabric, a piece of the stretchable sheet is cut out of the stretchable sheet 70, and the non-woven fabrics 85 and 86 are separated from the elastic filaments 87a.

Next, the separated elastic filaments 87a are cut in the length of 10 mm to create five samples. Both sides of the cut-out sample in the length direction are fixed between a pair of chucks of the Tensilon tensile tester described above.

To fix the sample, a portion with a 2.5-mm width from the end edge in each of both ends of the sample in the length direction is nipped with the chuck to be fixed at an air pressure of at least 1 MPa. A chuck interval is set to 5 mm, and the sample is fixed in a natural state. It should be noted that the chuck interval is appropriately adjusted in accordance with the length of the sample piece. The sample is then extended at 50 mm/min in the length direction of the sample up to the extension rate of 100%, and such a state of the sample is maintained for six hours under the temperature condition of 40°C. Subsequently, the extended state is gradually released for contraction, and the degree of elongation of the sample when the tensile stress is zero is measured to obtain a residual strain.

[0151] [Extension Recovery Rate and Degree of Elongation of Stretchable Sheet and Non-stretchable Sheet] The exterior member 39 of the disposable diaper 30 described above includes the first sheet 44 as a stretchable sheet, and the second sheet 12 as a non-stretchable sheet.

The stretchable non-woven fabric means a fabric having 70% or more of a recovery rate (extension recovery rate) when the fabric is extended by 100% in at least the same direction as a contraction direction. Further, a degree of elongation of the stretchable non-woven fabric used in this embodiment is preferably 100% or more, and more preferably 150% or more. The extension recovery rate and the degree of elongation can be measured as follows.

(Measurement for Extension Recovery Rate) A sample piece of a stretchable sheet having a length of 50 mm and a width of 25 mm is prepared. After the sample piece is fixed at a chuck interval LO and extended to a length of L2 (L2 = L0x2) at 100 extension at a rate of 300 mm/min by using the Tensilon tensile tester described above, when the sample piece starts to recover at a rate similar to a tensile rate and a tensile load reaches zero, the length of the sample piece is assumed as a length Ll after extension recovery. The extension recovery rate at 100% extension is calculated from the following expression.

Extension recovery rate at 100% extension (%) = {(52-L1)/(L2-LO)Ix100 (Method of Measuring Degree of Elongation) A sample piece with the same dimension as the dimension of the sample piece used in the method of measuring the extension recovery rate is extended under conditions similar to those in the method of measuring the extension recovery rate, and the degree of elongation when the sample piece is broken is assumed as the degree of elongation.

[0152] <Ninth Embodiment> A stretchable sheet 99 according to this embodiment will 113 be described with reference to Fig. 28. It should be noted that configurations similar to those in the above embodiments will be denoted by similar reference symbols and description thereof will be omitted in some cases.

Fig. 28 is a schematic cross-sectional view of the stretchable sheet 99. Fig. 28 is a view showing a state where a boundary surface between a first non-woven fabric 85 and a second non-woven fabric 86 is spread in a planar shape such that the undulations of the corrugated shape of elastic filaments 87a are made straight, with the elastic filaments 87a being not extended.

The stretchable sheet 70 of the first embodiment has been configured such that the projections 71 on one surface are positioned to face the positions of the projections 74 on the other surface in the thickness direction.

In contrast to this, as shown in Fig. 28, the stretchable sheet 99 of the ninth embodiment is configured such that a projection 71 on one surface is positioned to face a position between projections 74 adjacent to each other on the other surface in the thickness direction.

[0153] In the stretchable sheet 99, the projection 74 of the first non-woven fabric 85 is positioned in a stretchable portion 95 of the first non-woven fabric 85, and a flat portion 75 is positioned in a connection portion 96. The projection 71 of the second non-woven fabric is positioned in a stretchable portion 97 of the second non-woven fabric 86, and a flat portion 72 is positioned in a connection portion 98. The length of the projection 74 (projection 71) in the Y-axis direction is longer than the length of the flat portion 75 (flat portion 72).

In this embodiment, the stretchable portion 95 in the first non-woven fabric 85 and the stretchable portion 97 in the second non-woven fabric 86 are positioned to partially face each other in the thickness direction. The stretchable portion 95 in the first non-woven fabric 85 faces, in the thickness direction, the connection portion 98 in the second non-woven fabric 86 and part of each of the stretchable portions 97 and 97 adjacent to the connection portion 98 and positioned on both sides of the connection portions 98.

In other words, in the stretchable sheet 99, there are no regions where a region including the connection portion 96 in the first non-woven fabric 85 and a region including the connection portion 98 in the second non-woven fabric 86 face each other in the thickness direction. In other words, the stretchable sheet 99 is configured to have no region including only the connection portions on the X-Y plane.

[0154] Here, the connection portions 96 (98) are indispensable to fix the first non-woven fabric 85 (second non-woven fabric 86) and the elastic filaments 87a, but the connection portions 96 (98) fail to generate stretch property.

In the stretchable sheet 99 of this embodiment, the flat portions (connection portions) on one surface are orovided to face the projections (stretchable portions) on the other surface in the thickness direction, and thus the projections (stretchable portions) can cancel out the non-generation of the stretch property in the flat portions (connection portions), and the stretch property can be generated also in the regions where the projections on one surface and the flat portions on the other surface face each other. Thus, the extension in the Y-axis direction can be generated on the entire X-Y plane.

[0155] In this embodiment, as in the first embodiment, the projections 74 and the projections 71 include high projections and low projections, respectively, and have dimensions similar to those in the first embodiment. In the stretchable sheet 99 including such high projections and low projections, relatively, a region in which the high projections are disposed is a low contraction stress region P2, and a region in which the low projections are disposed is a high contraction stress region Pl.

Such a stretchable sheet 99 having mutually different contraction stresses can be applied to an exterior member of a disposable diaper and the like, as with the case of the stretchable sheet 70 of the first embodiment.

[0156] <Other Embodiments of Stretchable Sheet> Hereinabove, the embodiments of the present invention have been described. However, the present invention is not limited to the embodiments described above and can be variously modified without departing from the gist of the present invention.

For example, in the stretchable sheet 70 of the first embodiment, the center of the projection 74 in the Y-axis direction, which is disposed on one surface, and the center of the projection 71 in the Y-axis direction, which is disposed on the other surface and faces the projection 74 in the thickness direction, are almost the same. Further, in the stretchable sheet 99 of the second embodiment, the center of the projection 74 in the Y-axis direction, which is disposed on one surface, and the center of the flat portion 72 in the Y-axis direction, which is disposed on the other surface and faces the projection 74 in the thickness direction, are almost the same. However, the positions at which the projections 74 and the projections 71 are disposed are not limited thereto.

[0157] For another example, the projection 71 and the flat portion 72 adjacent to one side of the projection 71 on one surface may be disposed facing, in the thickness direction, the projection 74 disposed on the other surface. In this case, the center of the projection 74 in the Y-axis direction, which is disposed on the other surface, is positioned between the center of the flat portion 72 in the Y-axis direction, which is disposed facing the projection 74, and the center of the projection 71 in the Y-axis direction, which is disposed facing the projection 74. Also in such a configuration, the projections are formed of the high projections and the low projections, and thus a stretchable sheet including a high contraction stress and a low contraction stress can be obtained. Further, such a positional relationship between the projections on one surface and the projections on the other surface can be adjusted by changing the positions of the teeth to be meshed of the toothed stretching rolls 91 and 92.

[0158] Further, in the embodiments of the disposable diapers described above, the exterior member includes the first sheet and the second sheet, but the exterior member may include only the first sheet. For the first sheet, the stretchable sheet 70 or the stretchable sheet 99 as described above can be used.

Further, in the embodiments described above, both the abdominal portion and the dorsal portion of the waist portion include the stretchable regions, but at least one of the abdominal portion or the dorsal portion may include the stretchable region.

[0159] Further, the composite sheet in which the first sheet (stretchable sheet) and the second sheet (non-stretchable sheet) are laminated is used for the waist portion of the exterior member of the disposable diaper in the first embodiment, and when the composite sheet is applied to a disposable diaper, the first sheet serving as a stretchable sheet is disposed on the outer surface side, and the second sheet is disposed on the inner surface side. However, the first sheet may be disposed on the inner surface side, and the second sheet may be disposed on the outer surface side.

Further, in the disposable diaper, part of an elastic element of the stretchable sheet in a region, of the waist portion, facing the absorbent member may be cut or removed to obtain a non-stretchable region. This allows no creases to occur in the absorbent member due to the action of the contraction of the stretchable sheet on the absorbent member and does not inhibit liquid absorbing performance of the absorbent member.

[0160] Further, the exterior member of the disposable diaper in the first embodiment includes the seamless sheet in which the abdominal portion and the dorsal portion are continuous with each other via the crotch portion. In contrast to this, as in a disposable diaper 45 shown in Fig. 29, the stretchable sheet according to the present invention can be used for an exterior member 59 in which the abdominal portion and the dorsal portion are separated from each other.

The exterior member 59 includes a composite sheet 49 including an abdominal portion 53a, a dorsal portion 53b, a bonding layer 13, and second sheets 12a and 12b. The stretchable sheets 70 and 99 according to the present invention can be applied to the abdominal portion 53a and the dorsal portion 53b, to obtain the diaper 45 having stretch property around the trunk.

[0161] Further, the absorbent article according to the present invention does not need to be a pull-on disposable diaper that is formed into a pants shape in advance by joining with the side seal portions as in the embodiments described above. In other words, the pant-type absorbent article according to the present invention may be a tape-type disposable diaper including a tape such as a hook-and-loop fastener instead of the side seal portions.

[0162] Moreover, the absorbent article according to the present invention does not need to be a disposable diaper for a baby or infant and may be, for example, a disposable diaper for an adult or a child. Moreover, the absorbent article according to the present invention does not need to be a disposable diaper as long as it is an absorbent article of a type to be worn on the lower half of a body. Examples of such an absorbent article include a pull-on sanitary napkin or a pull-on incontinence pad.

[0163] Regarding the embodiments as described above, the present invention further discloses the following absorbent articles. <1>

A pant-type absorbent article, comprising: an absorbent member positioned in a crotch; a waist portion including an abdominal portion and a dorsal portion that are positioned around a trunk; and a crotch portion that is positioned between the abdominal portion and the dorsal portion and holds the absorbent member together with the abdominal portion and the dorsal portion, at least one of the abdominal portion and the dorsal portion including a stretchable sheet, the stretchable sheet including a first region and a second region, the second region being positioned on an upper side of the first region in an up-down direction orthogonal to a circumferential direction of the trunk, the stretchable sheet including an elastic resin and a non-woven fabric layer that contains the elastic resin, the first region and the second region having mutually different contraction stresses in the circumferential direction, the first region and the second region having an equal dimension in the circumferential direction in a natural state. <2>

The pant-type absorbent article according to <1>, wherein the stretchable sheet includes a first sheet including the non-woven fabric layer that contains the elastic resin, a second sheet including a non-stretchable nonwoven fabric that faces the first sheet, and a bonding layer that bonds the first sheet and the second sheet to each other. <3>

The pant-type absorbent article according to <2>, wherein the second sheet includes a plurality of raised portions that are raised on a side opposite to the first sheet, the plurality of raised portions forming a sequence of patterns, and the bonding layer is disposed over the first region and 121 the second region. <4>

The pant-type absorbent article according to <3>, wherein the bonding layer includes a plurality of bonding portions that are disposed away from each other in the circumferential direction and are continuously or discontinuously disposed along one direction over the first region and the second region. <5>

The pant-type absorbent article according to <4>, wherein the plurality of bonding portions are continuously or discontinuously disposed along the up-down direction. <6>

The pant-type absorbent article according to <4>, wherein the plurality of bonding portions are arranged in a staggered manner. <7>

The pant-type absorbent article according to <1>, wherein the stretchable sheet is a single first sheet including the non-woven fabric layer that contains the elastic resin. <8>

The pant-type absorbent article according to any one of <1> to <7>, wherein the contraction stress of the first region is higher than the contraction stress of the second region. <9>

The pant-type absorbent article according to any one of <1> to <8>, wherein a weight of the elastic resin per unit area in the first region is heavier than a weight of the elastic resin per unit area in the second region. <10>

The pant-type absorbent article according to any one of <1> to <8>, wherein the elastic resin includes a plurality of elastic fibers, and a density of the plurality of elastic fibers in the first region is higher than a density of the plurality of elastic fibers in the second region. <11>

The pant-type absorbent article according to any one of <1> to <8>, wherein the elastic resin includes a plurality of elastic fibers, and a thickness of the plurality of elastic fibers in the first region is thicker than a thickness of the plurality of elastic fibers in the second region. <12>

The pant-type absorbent article according to any one of <1> to <8>, wherein the elastic resin includes a plurality of elastic filaments continuous in a stretching direction, and the plurality of elastic filaments are disposed away from each other in the up-down direction along the circumferential direction, and an arrangement interval of the plurality of elastic filaments in the first region is narrower than an arrangement interval of the plurality of elastic filaments in the second region. <13>

The pant-type absorbent article according to <12>, wherein a thickness of the plurality of elastic filaments is identical in the first region and in the second region. <14>

The pant-type absorbent article according to any one of <1> to <13>, wherein the stretchable sheet further includes a third region that is positioned in an edge portion on the upper side in the up-down direction and is obtained by folding back the stretchable sheet toward a lower side in the up-down direction, and the contraction stress of the third region in the circumferential direction is identical to or lower than the contraction stress of the first region and is higher than the contraction stress of the second region. <15> The pant-type absorbent article according to <14>, wherein a length of the third region in the up-down direction is equal to or smaller than a half of a length of the second region. <16>

The pant-type absorbent article according to <14> or <15>, further comprising an elastic member disposed along the circumferential direction within the stretchable sheet folded back in the third region. <17>

The pant-type absorbent article according to any one of <1> to <16>, wherein the contraction stress of the first region is preferably 1.4 cN/mm or more and more preferably 2 cN/mm or more, and further, preferably 5 cN/mm or less, and is preferably 1.4 cN/mm or more and 5 cN/mm or less, and more preferably 2 cN/mm or more and 5 cN/mm or less. <18>

The pant-type absorbent article according to any one of <1> to <17>, wherein the contraction stress of the second region is preferably 0.1 cN/mm or more and more preferably 0.5 cN/mm or more, and further, preferably 3 cN/mm or less and more preferably 2.5 cN/mm or less, and is preferably 0.1 cN/mm or more and 3 cN/mm or less, and more preferably 0.5 cN/mm or more and 2.5 cN/mm or less. <19>

The pant-type absorbent article according to any one of <14> to <16>, wherein the contraction stress of the third region is preferably 1.4 cN/mm or more and more preferably 1.5 cN/mm or more, and further, preferably 4 cN/mm or less and more preferably 3.5 cN/mm or less, and is preferably 1.4 cN/mm or more and 4 cN/mm or less, and more preferably 1.5 cN/mm or more and 3.5 cN/mm or less. <20>

The pant-type absorbent article according to any one of <1> to <19>, wherein the contraction stress of the first region is preferably 1.2 times or more and more preferably 1.4 times or more the contraction stress of the second region, and further, preferably 3 times or less and more preferably 2.5 times or less the contraction stress of the second region, and is preferably 1.2 times or more and 3 times or less, and more preferably 1.4 times or more and 2.5 times or less the contraction stress of the second region. <21>

The pant-type absorbent article according to any one of <14> to <16> and <19>, wherein the contraction stress of the first region is preferably 1.1 times or more and more preferably 1.5 times or more the contraction stress of the third region, and further, preferably 2.5 times or less and more preferably 2 times or less the contraction stress of the third region, and is preferably 1.1 times or more and 2.5 times or less, and more preferably 1.5 times or more and 2 times or less the contraction stress of the third region. <22>

The pant-type absorbent article according to any one of <1> to <21>, wherein a length of the first region in the up-down direction is preferably 1.0 times or more and more preferably 1.2 times or more a length of the second region, and further, preferably 2 times or less and more preferably 1.8 times or less the length of the second region, and is preferably 1.0 times or more and 2 times or less, and more preferably 1.2 times or more and 1.8 times or less the length of the second region. <23>

The pant-type absorbent article according to any one of <14> to <16>, <19>, and <21>, wherein a length of the third region in the up-down direction is preferably 0.5 cm or more, and further, preferably 5 cm or less, more preferably 3 cm or less, and even more preferably 1.5 cm or less, and is preferably 0.5 cm or more and 5 cm or less, more preferably 0.5 cm or more and 3 cm or less, and even more preferably 0.5 to 1.5 cm or less. <24>

The pant-type absorbent article according to <16>, wherein the elastic member is disposed in each of the abdominal portion and the dorsal portion over an entire width along the circumferential direction such that, in a natural state where no tension is applied, the elastic member has a length equal to or larger than the width of each of the abdominal portion and the dorsal portion along the circumferential direction in a natural state.

[0164] <25> A stretchable sheet, comprising: a plurality of elastic filaments stretchable in a first direction; and two non-woven fabrics that are welded to the elastic filaments and disposed facing each other via the plurality of elastic filaments, the non-woven fabrics each including a plurality of projections that are intermittently disposed along the first direction and extend along a second direction orthogonal to the first direction, and a flat portion that is disposed between Projections adjacent to each other among the plurality of projections and extends along the second direction, the projections including a first projection and a second projection along the second direction, the first projection and the second projection having mutually different heights, the second projection having a higher height than the height of the first projection.

[0165] <26> The stretchable sheet according to <25>, wherein at least one of the two non-woven fabrics includes a fiber having a residual strain that is 70% or less after application of 100% extension. <27>

The stretchable sheet according to <25> or <26>, wherein in at least one of the two non-woven fabrics, the fiber constituting the non-woven fabric is a fiber having a residual strain that is 50% or more and 70% or less after application of 100% extension. <28>

The stretchable sheet according to <26> or <27>, wherein the fiber has a residual strain that is 55% or more and 65% or less after application of 100% extension. <29>

The stretchable sheet according to any one of <25> to <28>, wherein the elastic filaments have a residual strain that is 60% or less after application of 100% extension for six hours under a temperature condition of 40°C. <30>

The stretchable sheet according to any one of <25> to <29>, wherein the elastic filaments have a residual strain that is 50% or more and 60% or less after application of 100% extension for six hours under the temperature condition of 40°C. [0166] <31> The stretchable sheet according to any one of <25> to <30>, wherein the stretchable sheet includes a low contraction stress region in which the second projection is disposed, and a high contraction stress region in which the first projection is disposed, each of the non-woven fabrics includes a plurality of thermally-fused portions in which a plurality of fibers constituting the non-woven fabric are thermally fused to each other, and a thermally-fused-portion-non-existence region having a rectangular shape is surrounded by the thermally-fused portions disposed adjacently to each other on a boundary between the high contraction stress region and the low contraction stress region and the thermally-fused Portions disposed adjacently to each other along the second direction via the boundary, and each side of the thermally-fused-portion-non-existence region is in contact with the thermally-fused portion and is parallel to the boundary or to an imaginary line orthogonal to the boundary, the thermallyfused-portion-non-existence region having a length in the second direction that is longer than a length of the thermally-fused-portion-non-existence region in the first direction. <32>

The stretchable sheet according to <31>, wherein the length of the thermally-fused-portion-non-existence region in the second direction is 1.5 times or more and 3 times or less the length of the thermally-fused-portion-non-existence region in the first direction. <33>

The stretchable sheet according to <31>, wherein the length of the thermally-fused-portion-non-existence region in the second direction is 1.8 times or more and 2.8 times or less the length of the thermally-fused-portion-nonexistence region in the first direction. <34>

The stretchable sheet according to any one of <25> to <33>, wherein the stretchable sheet includes a low contraction stress region in which the second projection is disposed, and a high contraction stress region in which the first projection is disposed, and a contraction stress per unit length in the first direction in the low contraction stress region is lower than a contraction stress per unit length in the first direction in the high contraction stress region.

[0167] <35> The stretchable sheet according to any one of <25> to <34>, wherein the stretchable sheet is a sheet that is continuous and seamless in a planar direction. <36>

The stretchable sheet according to any one of <25> to <35>, wherein the elastic filaments are directly welded to the nonwoven fabrics. <37>

The stretchable sheet according to any one of <25> to <36>, wherein a boundary surface between the two non-woven fabrics of the stretchable sheet has a corrugated shape. <38>

The stretchable sheet according to any one of <25> to <37>, wherein a fiber constituting the projection is peeled from the elastic filaments. <39>

The stretchable sheet according to any one of <25> to <38>, wherein a fiber density of the projection is lower than a fiber density of the flat portion.

[0168] <40> The stretchable sheet according to any one of <25> to <39>, wherein in the thickness direction, the projection on one surface of the stretchable sheet is configured to be positioned at a position of the projection on the other surface, and the flat portion on the one surface is positioned at a position of the flat portion on the other surface. <41>

The stretchable sheet according to any one of <25> to <40>, wherein the plurality of projections are seamlessly continuous along the second direction. <42>

The stretchable sheet according to any one of <25> to <41>, wherein a height of the first projection is 0.5 times or more and 0.8 times or less a height of the second projection. <43>

The stretchable sheet according to any one of <25> to <42>, wherein the height of the first projection is 0.6 times or more and 0.7 times or less the height of the second projection. <44>

The stretchable sheet according to any one of <25> to <43>, wherein a ratio of the height of the projection to a distance between the projections (height of projection/distance between projections) has a value of 1 or less. <45> The stretchable sheet according to any one of <25> to <44>, wherein the projection constitutes a stretchable portion that is stretchable in the first direction, and the flat portion constitutes a connection portion that is more difficult to extend and contract in the first direction than the stretchable portion.

[0169] <46> An absorbent article, comprising the stretchable sheet according to any one of <25> to <45>. <47>

The absorbent article according to <46>, wherein the absorbent article comprises: an absorbent member positioned in a crotch; a waist portion including an abdominal portion and a dorsal portion that are positioned around a trunk, at least one of the abdominal portion and the dorsal portion being constituted using the stretchable sheet that is stretchable in a circumferential direction of the trunk; and a crotch portion that is positioned between the abdominal portion and the dorsal portion and holds the absorbent member together with the abdominal portion and the dorsal portion, and the waist portion constituted using the stretchable sheet includes a center region positioned at the center among regions obtained by equally dividing the waist portion into three in a direction orthogonal to the circumferential direction, and a pair of end regions positioned facing each other via the center region, the first projection being disposed in the center region, the second projection being disposed in at least one of the pair of end regions. <48>

The absorbent article according to <47>, wherein the waist portion constituted using the stretchable sheet includes the second projections disposed in both the pair of end regions positioned facing each other via the center region. <49>

The absorbent article according to any one of <46> to <48>, wherein the absorbent article includes an exterior member and the absorbent member, and the exterior member includes the stretchable sheet. <50>

The absorbent article according to <49>, wherein the exterior member includes the stretchable sheet and a base sheet, and the stretchable sheet and the base sheet are joined without an elastic member. <51>

The absorbent article according to any one of <46> to <50>, wherein the absorbent article is a disposable diaper for a baby or infant.

[0170] <52> A method of producing a stretchable sheet, comprising: the step of obtaining a laminate by supplying heated elastic filaments between a first non-woven fabric and a second non-woven fabric and laminating the heated elastic filaments, the first non-woven fabric, and the second non-woven fabric with pressure; and the stretching step of performing roll stretching by passing the laminate through a pair of toothed stretching rolls, each of the toothed stretching rolls including a large depth portion and a small depth portion having a smaller depth than a depth of the large depth portion. <53>

The method of producing a stretchable sheet according to <52>, wherein a tension to be applied to the stretchable sheet after the stretching step is made weaker than a tension to be applied to the laminate before the stretching. <54>

A method of producing an absorbent article, comprising: the step of extending the stretchable sheet produced by the production method according to <52> or <53> at a constant extension rate and obtaining an exterior member by attaching a base sheet to the stretchable sheet; and the step of superimposing an absorbent member and the exterior member on each other. <55>

The method of producing an absorbent article according to <54>, wherein the stretchable sheet and the base sheet are joined without an elastic member.

Industrial Applicability

[0171] According to the present invention, an appearance and the sense of touch like pants as underwear (fabric) are presented while maintaining fitting property and a fundamental performance for a diaper. Further, according to the present invention, a stretchable sheet including regions having mutually different contraction stresses is obtained.

Claims

Claims [1] A pant-type absorbent article, comprising: an absorbent member positioned in a crotch; a waist portion including an abdominal portion and a dorsal portion that are positioned around a trunk; and a crotch portion that is positioned between the abdominal portion and the dorsal portion and holds the absorbent member together with the abdominal portion and the dorsal portion, at least one of the abdominal portion and the dorsal portion including a stretchable sheet, the stretchable sheet including a first region and a second region, the second region being positioned on an upper side of the first region in an up-down direction orthogonal to a circumferential direction of the trunk, the stretchable sheet including an elastic resin and a non-woven fabric layer that contains the elastic resin, the first region and the second region having mutually different contraction stresses in the circumferential direction, the first region and the second region having an equal dimension in the circumferential direction in a natural state.[2] The pant-type absorbent article according to claim 1, wherein the stretchable sheet includes a first sheet including the non-woven fabric layer that contains the elastic resin, a second sheet including a non-stretchable non-woven fabric that faces the first sheet, and a bonding layer that bonds the first sheet and the second sheet to each other.[3] The pant-type absorbent article according to claim 2, wherein the second sheet includes a plurality of raised portions that are raised on a side opposite to the first sheet, the plurality of raised portions forming a sequence of patterns, and the bonding layer is disposed over the first region and the second region.[4] The pant-type absorbent article according to claim 3, wherein the bonding layer includes a plurality of bonding portions that are disposed away from each other in the circumferential direction and are continuously or discontinuously disposed along one direction over the first region and the second region.[5] The pant-type absorbent article according to claim 4, wherein the plurality of bonding portions are continuously or discontinuously disposed along the up-down direction.[6] The pant-type absorbent article according to claim 4, wherein the plurality of bonding portions are arranged in a staggered manner.[7] The pant-type absorbent article according to any one of claims 1 to 6, wherein the contraction stress of the first region is higher than the contraction stress of the second region.[8] The pant-type absorbent article according to any one of claims 1 to 7, wherein a weight of the elastic resin per unit area in the first region is heavier than a weight of the elastic resin per unit area in the second region.[9] The pant-type absorbent article according to any one of claims 1 to 7, wherein the elastic resin includes a plurality of elastic fibers, and a density of the plurality of elastic fibers in the first region is higher than a density of the plurality of elastic fibers in the second region.[10] The pant-type absorbent article according to any one of claims 1 to 7, wherein the elastic resin includes a plurality of elastic fibers, and a thickness of the plurality of elastic fibers in the first region is thicker than a thickness of the plurality of elastic fibers in the second region.[11] The pant-type absorbent article according to any one of claims 1 to 7, wherein the elastic resin includes a plurality of elastic filaments continuous in a stretching direction, and the plurality of elastic filaments are disposed away from each other in the up-down direction along the circumferential direction, and an arrangement interval of the plurality of elastic filaments in the first region is narrower than an arrangement interval of the plurality of elastic filaments in the second region.[12] The pant-type absorbent article according to claim 11, wherein a thickness of the plurality of elastic filaments is identical in the first region and in the second region.[13] The pant-type absorbent article according to any one of claims 1 to 12, wherein the stretchable sheet further includes a third region that is positioned in an edge portion on the upper side in the up-down direction and is obtained by folding back the stretchable sheet toward a lower side in the up-down direction, and the contraction stress of the third region in the circumferential direction is identical to or lower than the contraction stress of the first region and is higher than the contraction stress of the second region.[14] The pant-type absorbent article according to claim 13, wherein a length of the third region in the up-down direction is equal to or smaller than a half of a length of the second region.[15] The pant-type absorbent article according to claim 13 or 14, further comprising an elastic member disposed along the circumferential direction within the stretchable sheet folded back in the third region.[16] The pant-type absorbent article according to claim 1, wherein the elastic resin includes an elastic filament, the stretchable sheet is a stretchable sheet including a plurality of the elastic filaments stretchable in a first direction, and two non-woven fabrics that are welded to the elastic filaments and disposed facing each other via the plurality of the elastic filaments, the non-woven fabric includes a plurality of projections that are intermittently disposed along the first direction and extend along a second direction orthogonal to the first direction, and a flat portion that is disposed between Projections adjacent to each other out of the plurality of projections and extends along the second direction, and the projections include a first projection and a second projection along the second direction, the first projection and the second projection having mutually different heights, the second projection having a higher height than a height of the first projection.[17] A stretchable sheet, comprising: a plurality of elastic filaments stretchable in a first direction; and two non-woven fabrics that are welded to the elastic filaments and disposed facing each other via the plurality of elastic filaments, the non-woven fabric including a plurality of projections that are intermittently disposed along the first direction and extend along a second direction orthogonal to the first direction, and a flat portion that is disposed between projections adjacent to each other among the plurality of projections and extends along the second direction, the projections including a first projection and a second projection along the second direction, the first projection and the second projection having mutually different heights, the second projection having a higher height than the height of the first projection.[18] The stretchable sheet according to claim 17, wherein at least one of the two non-woven fabrics includes a fiber having a residual strain that is 70% or less after application of 100% extension.[19] The stretchable sheet according to claim 17 or 18, wherein the elastic filaments have a residual strain that is 60% or less after application of 100% extension for six hours under a temperature condition of 40°C.[20] The stretchable sheet according to any one of claims 17 to 19, wherein the stretchable sheet includes a low contraction stress region in which the second projection is disposed, and a high contraction stress region in which the first projection is disposed, each of the non-woven fabrics includes a plurality of thermally-fused portions in which a plurality of fibers constituting the non-woven fabric are thermally fused to each other, and a thermally-fused-portion-non-existence region having a rectangular shape is surrounded by the thermally-fused portions disposed adjacently to each other on a boundary between the high contraction stress region and the low contraction stress region and the thermally-fused Portions disposed adjacently to each other along the second direction via the boundary, and each side of the thermally-fused-portion-non-existence region is in contact with the thermally-fused portion and is parallel to the boundary or to an imaginary line orthogonal to the boundary, the thermallyfused-portion-non-existence region having a length in the second direction that is longer than a length of the thermally-fused-portion-non-existence region in the first direction.[21] The stretchable sheet according to any one of claims 17 to 20, wherein the stretchable sheet includes a low contraction stress region in which the second projection is disposed, and a high contraction stress region in which the first projection is disposed, and a contraction stress per unit length in the first direction in the low contraction stress region is lower than a contraction stress per unit length in the first direction in the high contraction stress region.[22] An absorbent article, comprising the stretchable sheet according to any one of claims 17 to 21.[23] The absorbent article according to claim 22, wherein the absorbent article comprises: an absorbent member positioned in a crotch; a waist portion including an abdominal portion and a dorsal portion that are positioned around a trunk, at least one of the abdominal portion and the dorsal portion being constituted using the stretchable sheet that is stretchable in a circumferential direction of the trunk; and a crotch portion that is positioned between the abdominal portion and the dorsal portion and holds the absorbent member together with the abdominal portion and the dorsal portion, and the waist portion constituted using the stretchable sheet includes a center region positioned at the center among regions obtained by equally dividing the waist portion into three in a direction orthogonal to the circumferential direction, and a pair of end regions positioned facing each other via the center region, the first projection being disposed in the center region, the second projection being disposed in at least one of the pair of end regions.[24] A method of producing a stretchable sheet, comprising: the step of obtaining a laminate by supplying heated elastic filaments between a first non-woven fabric and a second non-woven fabric and laminating the heated elastic filaments, the first non-woven fabric, and the second nonwoven fabric with pressure; and the stretching step of performing roll stretching by passing the laminate through a pair of toothed stretching rolls, each of the toothed stretching rolls including a large depth portion and a small depth portion having a smaller depth than a depth of the large depth portion.