WO2012137519A1

WO2012137519A1 - Disposable absorbent article

Info

Publication number: WO2012137519A1
Application number: PCT/JP2012/002452
Authority: WO
Inventors: Kunihiko Katsuragawa; Kenichi Sasayama; Makoto Ichikawa
Original assignee: Unicharm Corporation
Priority date: 2011-04-08
Filing date: 2012-04-06
Publication date: 2012-10-11
Also published as: JP2012217652A; JP5951189B2

Abstract

A diaper (1) includes an annular waist panel (10) having a longitudinal direction (Y) and a transverse direction (X) and a skin-facing side and a non-skin-facing side and includes an absorbent chassis (30) connected to the annular waist panel (10). The absorbent chassis (30) includes a first sheet (29a), a second sheet (29b), a pair of end flaps (35, 36) extending along opposite ends (31, 32) of the first and second sheets (29a, 29b), respectively, and a pair of side flaps (38) extending along opposite side edges (29c, 29d) of the first and second sheets (29a, 29b), respectively, wherein these side flaps (38) are folded onto the skin-facing side. Linear adhesives (90) serving to bond the first sheet (29a) and the second sheet (29b) to each other continuously extend in the longitudinal direction (Y) from the front end (31) to the rear end (32) of the opposite ends (31, 32) wherein the first sheet (29a), the second sheet (29b) and the linear adhesives (90) cooperate together to define channels (91) opened along one side in the transverse direction (X) and extending in the longitudinal direction (Y).

Description

DISPOSABLE ABSORBENT ARTICLE

This disclosure relates to various types of disposable absorbent articles.

Background

Disposable absorbent articles having longitudinal and transverse directions and provided with an absorbent structure which includes a skin-facing side and a non-skin-facing side are known.

For example, JP 2003-199788A (PTL 1) discloses a disposable absorbent article including a pair of side flaps extending along transversely opposite side edges of an absorbent structure and a pair of end flaps extending along longitudinally opposite ends of the absorbent structure. First elastic members extending in the longitudinal direction are attached under tension to the respective side flaps so as to exert a contractile force upon the associated side flaps. In a similar fashion, second elastic members extending in the transverse direction are attached under tension to the respective end flaps so as to exert a contractile force upon the associated end flaps.

According to this disposable absorbent article, it is possible for the side flaps to prevent body waste such as urine from leaking transversely outward and it is also possible for the end flaps to prevent such body waste from leaking longitudinally outward.

JP 2003-199788A

Summary

In the disposable absorbent article disclosed in PTL 1, the absorbent structure is provided on its transversely opposite sides with the side flaps and the absorbent structure is provided on its longitudinally opposite ends also with the end flaps. The inventor(s) has noted that, with such an arrangement, the wearer's skin might be tightly enclosed by the side flaps, the end flaps and the absorbent structure. In consequence, humidity of an internal space defined between the wearer's skin and the absorbent structure increases as time elapses. In other words, the breathability of the internal space might be poor so that stuffiness generating due to increasing humidity in the internal space and bad odor of body waste pervading in the internal space may make a wearer or a third person such as care personnel serving to exchange the diaper uncomfortable.

A first aspect of this invention relates to a disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, and including:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding the first sheet and the second sheet to each other and extending in the longitudinal direction from the front end to the rear end of the absorbent chassis.

The first aspect of this invention further includes:
the first sheet, the second sheet and the adhesive cooperate together to define channels each opened along one side thereof in the transverse direction and extending in the longitudinal direction.

A second aspect of this invention relates to a disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, and including:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding layers of one of the sheets folded onto one of the skin-facing side and the non-skin-facing side to define bent segments, the adhesive extending in the longitudinal direction from the front end to the rear end of the absorbent chassis.

The second aspect of the invention further includes:
the folded sheet and the adhesive cooperate together to form channels extending in the longitudinal direction.

Fig. 1 is a perspective view of a disposable diaper according to a first embodiment of this invention on the first aspect thereof. Fig. 2 is a partially cutaway developed plan view of the diaper as viewed from its skin-facing side. Fig. 3 is a sectional view taken along line III-III in Fig. 2. Fig. 4 is a sectional view taken along line IV-IV in Fig. 2. Fig. 5 is a perspective view illustrating a manner in which a waist member and an absorbent chassis are bonded to each other. Fig. 6 is a plan view of an absorbent structure. Fig. 7 is a sectional view taken along line VII-VII in Fig. 6. Fig. 8 is a sectional view similar to Fig. 3 and showing a disposable diaper according to a second embodiment of this invention on the first aspect thereof. Fig. 9 is a sectional view similar to Fig. 3 and showing a disposable diaper according to a third embodiment of this invention on the first aspect thereof. Fig. 10 is a sectional view similar to Fig. 3 and showing a disposable diaper according to an embodiment of this invention on the second aspect thereof.

Details of various disposable absorbent articles according to some embodiments of this invention will be described hereunder as disposable diapers which are typical examples of disposable absorbent articles.

<First Embodiment>
Referring to Fig. 1, a diaper 1 of pants-type has a waist-opening 10a and a pair of leg-openings 10b. X indicates a transverse direction, Y indicates a longitudinal direction being orthogonal to the transverse direction X, and Z indicates a front-back direction being orthogonal to both the transverse direction X and the longitudinal direction Y.

The diaper 1 includes an annular waist panel 10 circumferentially extending around the wearer's waist, an absorbent chassis 30 extending in a direction intersecting with this circumferential direction. The waist panel 10 includes a front panel 11 and a rear panel 12 which have respective pairs of

side edges

11a, 12a opposite in the transverse direction X. The front and

rear panels

11, 12 have their inner surfaces joined to each other along the respective pairs of

side edges

11a, 12a at seams 13 arranged continually in the longitudinal direction Y.

Referring to Fig. 2, the diaper 1 is shown in a state where the front and

rear panels

11, 12 are peeled off from each other along the seams 13 and developed in the transverse direction X and the front-back direction Z as viewed from a side of the diaper 1 adapted for facing the wearer's skin (this side may be referred to hereinafter simply as the skin-facing side, and a side opposite to this side may be referred to hereinafter simply as the non-skin-facing side). P-P indicates a longitudinal imaginary center line bisecting the diaper 1 in the transverse direction X and extending in the longitudinal direction Y, and Q-Q indicates a transverse imaginary center line bisecting the diaper 1 in the longitudinal direction Y and extending in the transverse direction X.

Referring to Figs. 3 and 4, the diaper 1 includes a front waist region 2, a rear waist region 3 and a crotch region 4 extending between the front and

rear waist regions

2, 3 so that these

regions

2, 4, 3 lie successively in the longitudinal direction Y. The front waist region 2 is adapted to cover the wearer's front waist region, the rear waist region 3 is adapted to cover the wearer's rear waist region and the crotch region 4 is adapted to cover the wearer's crotch region.

The front and

rear waist regions

2, 3 are respectively defined by the front and

rear panels

11, 12, and the crotch region 4 is defined by the absorbent chassis 30. As illustrated, the front panel 11, the rear panel 12 and the absorbent chassis 30 are respectively symmetric about the longitudinal imaginary center line P-P.

The front and

rear panels

11, 12 respectively include inner sheets 20 lying on the skin-facing side, outer sheets 21 lying on the non-skin-facing side and waist elastic members 22 interposed between these inner and

outer sheets

20, 21. As materials for the inner and

outer sheets

20, 21, moisture-permeable fibrous nonwoven fabrics may be used. The waist inner and

outer sheets

20, 21 are bonded to each other with hot melt adhesives (not shown).

The waist elastic members 22 are interposed under tension between the inner and

outer sheets

20, 21 with hot melt adhesives (not shown) so that these elastic members 22 exert a contractile force on these

sheets

20, 21. In the state illustrated in Fig. 1, the waist elastic members 22 are contracted in the transverse direction X and gathers 15 are in the inner and

outer sheets

20, 21 under the effect of the contractile force of the waist elastic members 22.

As illustrated in Fig. 2, the absorbent chassis 30 includes a backsheet 29 lying on the non-skin-facing side, an absorbent structure 80 disposed on the backsheet 29 and a bodyside liner 28 covering the absorbent structure 80.

As illustrated in Figs. 4 and 6, the absorbent structure 80 includes a liquid absorbent/dispersant upper wrap 81, a lower wrap 82 and an absorbent material 83 interposed between the upper and

lower wraps

81, 82. It should be noted that respective sizes of absorbent polymer particles 84 forming the absorbent material 83 are exaggerated to clarify the presence of the absorbent polymer particles 84.

The upper wrap 81 is formed of a water-permeable fibrous nonwoven fabric made of a thermoplastic synthetic resin and treated to become hydrophilic. For example, the upper wrap 81 may be formed of an SMS (spunbonded, meltblown and spunbonded) fibrous nonwoven fabric made of polypropylene and treated to become hydrophilic. More specifically, as the upper wrap 81, a water-permeable SMS fibrous nonwoven fabric having a basis mass of about 10.0 to about 12.0 g/m² obtained by sandwiching a melt blown nonwoven fabric having a basis mass of about 0.5 to about 2.0 g/m² between a pair of spunbonded nonwoven fabrics each having a basis mass of about 4.0 to about 5.0 g/m² and treated to become hydrophilic is used.

The lower wrap 82 is formed of a water-permeable or poorly water permeable fibrous nonwoven fabric made of a thermoplastic synthetic resin and treated to become hydrophobic or water-repellent. For example, the lower wrap 82 is obtained by treating an SMS fibrous nonwoven fabric made of polypropylene to become hydrophobic or water-repellent. More specifically, as the lower wrap 82, poorly-water permeable SMS fibrous nonwoven fabric having a basis mass of about 10.0 to about 13.0 g/m² obtained by sandwiching a melt blown nonwoven fabric having a basis mass of about 0.5 to about 2.0 g/m² between a pair of spunbonded nonwoven fabrics each having a basis mass of about 4.0 to about 6.0 g/m² and treating such sheet assembly to become hydrophobic or water-repellent is used.

The absorbent material 83 preferably contains none of hydrophilic fibers and is composed of discrete absorbent polymer particles 84 alone. The absorbent polymer particles 84 may be selected from the known polymers which are water-insoluble, water swellable and have absorption capacity corresponding at least to several dozen times or more of own mass thereof, for example, starch-based, acrylic acid-based or amino acid-based particulate or fibriform polymers. However, the material 83 may contain hydrophilic fibers of 30% or less mass.

As illustrated in Fig. 6, the absorbent structure 80 includes absorbing regions 85 in which the absorbent polymer particles 84 are contained and sealing regions 86 in which none of the absorbent polymer particles 84 and the hydrophilic fibers is substantially contained wherein these regions 85 and regions 86 are alternately arranged in the longitudinal direction Y.

As exemplarily illustrated in Fig. 4, in the respective absorbing regions 85, the upper wrap 81 and the lower wrap 82 are spaced from each other and the lower wrap 82 is coated with adhesive 87 such as hot melt adhesive so that the absorbent polymer particles 84 may be bonded to at least the lower wrap 82. The adhesive 87 may be applied to the entire area of the lower wrap 82. In this exemplarily illustrated diaper 1, eight absorbing regions 85 are arranged. The sealing regions 86 are defined between each absorbing region 85 and around a peripheral region of the absorbent structure 80, i.e., around peripheral regions of the upper and

lower wraps

81, 82. In other words, the sealing regions 86 surround each absorbing region 85.

In the sealing regions 86, as illustrated in Figs. 4 and 7, the upper wrap 81 is coated with adhesive 88 such as hot melt adhesive so that the upper wrap 81 is bonded to the lower wrap 82 with

adhesives

87, 88. The adhesive 88 may be applied to the entire areas of the respective sealing regions 86.

The absorbent structure 80 are fixed with hot melt adhesive 78 between the bodyside liner 28 and the upper wrap 81 and with hot melt adhesive 79 between the backsheet 29 and the lower wrap 82.

The absorbent structure 80 configured as has been described has a bending resistance of about 15 to about 140 mm in the longitudinal direction. The bending resistance was measured by the measuring method A for bending resistance prescribed by JIS L 1096 (45 degrees cantilever method). Specifically, test pieces (having a length dimension of 50 mm in the transverse direction X and a length dimension of 150 mm in the longitudinal direction Y) were carefully scissors-cut out from the absorbent chassis 30 of the respective diapers 1 in the vicinity of the transverse imaginary center line Q of the diaper 1 so as not to include the fold lines. Measurement was carried out three times on the upper side and the lower side. The measured values as indicated above were averaged values of such measurements which had been repeated three times.

As a material for the bodyside liner 28, any known material may be used as long as it is a liquid-permeable sheet, for example, it may be selected from the group of air-through nonwoven fabrics, spunbonded nonwoven fabrics, porous plastic films treated to become hydrophilic or a laminate sheet of any one of these nonwoven fabrics and plastic films.

The bodyside liner 28 has a length dimension in the transverse direction X larger than that of the absorbent structure 80 and, as illustrated in Fig. 4, opposite side edges 28a thereof extending outward beyond the absorbent structure 80 are folded onto the lower side of the absorbent structure 80. As illustrated in Fig. 2, the bodyside liner 28 has a length dimension in the longitudinal direction Y larger than that of the absorbent structure 80 to define opposite extensions 28b extending outward beyond the absorbent structure 80 in the longitudinal direction Y. In this way, the bodyside liner 28 covers the entire upper side of the absorbent structure 80.

As a material for the backsheet 29, any known material may be used as long as it is a poorly-liquid permeable or liquid-impermeable. For example, it may be selected from the group of spunbonded/meltblown/spunbonded (SMS) nonwoven fabrics, air-through nonwoven fabrics, point-bonded nonwoven fabrics, spunbonded nonwoven fabrics or laminate sheets composed of any one of these nonwoven fabrics and plastic films. In the exemplarily illustrated backsheet 29, used is a laminate sheet composed of a moisture-permeable first sheet 29a of a fibrous nonwoven fabric and a liquid-impermeable second sheet 29b of a plastic film. The second sheet 29b may be made of, for example, a polyethylene-based thermoplastic synthetic resin having a basis mass of about 16 to about 24 g/m². In a central area 37, the first sheet 29a lies on the non-skin-facing side and the second sheet 29b lies on the skin-facing side. In respective side flaps 38, the first sheet 29a lies on the skin-facing side and the second sheet 29b lies on the non-skin-facing side. As illustrated in Figs. 3 and 4, opposite side edges 29c of the first sheet 29a and opposite side edges 29d of the second sheet 29b extend inward in the transverse direction X by the same distance. In other words, a length dimension of the second sheet 29b in the transverse direction X is smaller than a length dimension of the first sheet 29a in the transverse direction X. The second sheet 29b in this illustrated embodiment is provided with a plurality of through-holes (not shown) extending from the skin-facing side to the non-skin-facing side so that the second sheet 29b also may be air-permeable, but remains liquid-impermeable.

As illustrated in Fig. 2, the backsheet 29 has length dimensions in the transverse direction X as well as in the longitudinal direction Y larger than those of both the bodyside liner 28 and the absorbent structure 80 so that the backsheet 29 have opposite ends 31, 32 extending outward beyond the absorbent structure 80 in the longitudinal direction Y, and the

opposite side edges

29c, 29d extending outward beyond the absorbent structure 80 in the transverse direction X. The absorbent chassis 30 further includes a pair of the side flaps 38 extending along the

opposite side edges

29c, 29d and a pair of front and rear end flaps 35, 36 wherein these flaps are defined by the backsheet 29.

The backsheet 29 has fold lines 39 extending along the

opposite side edges

29c, 29d in the longitudinal direction Y to define the rectangular central area 37 in the transverse direction X, and the side flaps 38 wherein the side flaps 38 are folded onto the skin-facing side of the central area 37.

In Fig. 2, the first sheet 29a is partially cutaway in the vicinity of the rear end 32 of the right side flap 38 to expose leg

elastic members

50, 60 and the first sheet 29a in the crotch region 4 is partially cutaway in the vicinity of the left side flap 38 to expose the leg

elastic members

50, 60 on the left side for convenience of illustration. Specifically, in the respective side flaps 38 of the backsheet 29, paired sets of the first leg elastic members 50 and paired sets of the second leg elastic members 60 are interposed between the first sheet 29a and the second sheet 29b symmetrically about the longitudinal imaginary center line P-P.

As materials for the leg

elastic members

50, 60, strand- or string-like or ribbon-like elastic members may be used. The leg

elastic members

50, 60 may be attached under tension to at least one of the first sheet 29a and the second sheet 29b with hot melt adhesives or the like. In this diaper 1, each of the side flaps 38 of the absorbent chassis 30 is provided with a set of the first leg elastic members 50 and a set of the second leg elastic members 60.

The paired sets of the first leg elastic members 50 are arranged so as to extend continuously in the respective side flaps 38 so that these two sets of the first leg elastic members 50 come closest to each other on the transverse imaginary center line Q, then gradually diverge apart from each other away from the transverse imaginary center line Q, and then extend in parallel to the longitudinal imaginary center line P-P in the vicinity of the opposite ends of the respective side flaps 38.

With the diaper put on the wearer's body, the first leg elastic members 50 contract around the wearer's legs and thereby prevent leak of body waste such as urine from occurring around the wearer's legs.

The second leg elastic members 60 are arranged so as to extend rectilinearly in the longitudinal direction Y. The paired sets of the second leg elastic members 60 extend in parallel to each other and in parallel also to the longitudinal imaginary center line P-P. These paired sets of the second leg elastic members 60 are arranged between the longitudinal imaginary center line P-P and the associated set of the first leg elastic members 50 in the respective side flaps 38.

With the diaper put on the wearer's body, the second leg elastic members 60 contract in the wearer's crotch region and thereby raise the side flaps 38 off the bodyside liner 28 to prevent body waste such as urine or feces from leaking in the transverse direction.

Referring to Fig. 5, the absorbent chassis 30 and the rear panel 12 of the waist panel 10 are bonded to each other with adhesive 74 applied to at least one of the absorbent chassis 30 and the rear panel 12. While this embodiment is described to apply the adhesive 74 to the rear panel 12 alone, it is possible to apply the adhesive 74 to the rear panel 12 alone or to apply the adhesive 74 not only to the rear panel 12 but also to the absorbent chassis 30.

An adhesive coated region 70 on the absorbent chassis 30 coated with the adhesive 74 such as hot melt adhesive includes (i) a first coated zone 71 extending in the transverse direction X in the central area 37, (ii) a pair of second coated zones 72 arranged in the respective side flaps 38, spaced from side edges 71a of the first coated zone 71, opposite to each other in the transverse direction X, and rectilinearly extending away from the longitudinal imaginary center line P-P, and (iii) a pair of third coated zones 73 arranged also in the respective side flaps 38, extending from ends 72a of the respective second zones 72 in the longitudinal direction Y so as to come close to the transverse imaginary center line Q-Q. The adhesive 74 with which the absorbent chassis 30 and the rear panel 12 are bonded to each other may extend continuously in the longitudinal direction Y in the respective side flaps 38 and continuously bond the absorbent chassis 30 to the waist panel 10 in the transverse direction X along the rear end 32 overlapping the rear waist region 3. In this manner, the waist panel 10 is bonded to the absorbent chassis 30 so that a rear pocket 75 is defined between the waist panel 10 and the absorbent chassis 30. In consequence, when the wearer is in a recumbent position, body waste such as feces can be collected in this rear pocket 75 and a waste containment capacity can be improved. In addition, in this diaper 1, the skin-facing side of the absorbent chassis 30 is bonded to the non-skin-facing side of the waist panel 10 and therefore the body waist containment capacity can further improved.

In the front waist region 2, an adhesive coated region 70a coated with the adhesive 74 with which the absorbent chassis 30 and the front panel 11 are bonded to each other is similar to the adhesive coated region 70 except that the respective third zones 73 include front zones 73a spaced from the transverse imaginary center line Q and rear zones 73b close to the transverse imaginary center line Q. The waist panel 10 and the absorbent chassis 30 are bonded to each other so that a front pocket 76 is defined between the waist panel 10 and the absorbent chassis 30.

As illustrated in Figs. 3 and 4, in the central area 37, the first sheet 29a and the second sheet 29b are bonded to each other with adhesive 98 applied to the central area 37. In the respective side flaps 38, the first sheet 29a and the second sheet 29b are bonded to each other with adhesive (not shown) applied to the second leg elastic members 60 and an adhesive 99 applied to at least one of the

sheets

29a, 29b to fix the first leg elastic members 50 to the

sheets

29a, 29b. The adhesive 99 is applied at a mass per unit area of about 5 to about 10 g/m². The adhesive 98 is applied so as to extend from the central area 37 to the side flaps 38 in which the adhesive 98 may overlap the adhesive 99.

An adhesive 90 such as a hot melt adhesive is provided in the form of a pair of linear adhesives continuously extending from the front end 31 to the rear end 32 of the absorbent chassis 30 to be spaced from the side edges 29c, 29d of the

respective sheets

29a, 29b by a dimension L1 as measured in the transverse direction X away from the longitudinal imaginary center line P-P. The dimension L1 is preferably about 1 to about 10 mm and more preferably about 1 to about 5 mm. The adhesive 90 is applied at a mass per unit area of about 3 to about 50 g/m² and this mass per unit area is preferably larger than a mass per unit area of, for example, the adhesive 99. In the respective side flaps 38, the first sheet 29a, the second sheet 29b and the adhesive 90 cooperate together to form channels 91 between the respective linear adhesives 90 and the associated

side edges

29c, 29d and these channels 91 are opened along one side thereof in the transverse direction X and continuously extend from the front end 31 to the rear end 32 of the absorbent chassis 30.

According to this diaper 1, the first sheet 29a, the second sheet 29b and the adhesive 90 cooperate together to form the channels 91 respectively opening inward as viewed in the transverse direction X and extending in the longitudinal direction Y. With this arrangement, the inner space of the diaper 1 defined between the absorbent structure 80 and the wearer's skin is kept in communication with the exterior of the diaper 1 through these channels 91. Specifically, the inner space of the diaper 1 is deformed in response to the wearer's movement such as walking, sitting down or getting up and, in consequence, air or vapor enters and leaves the inner space through the channels 91. In this way, breathability of the diaper 1 can be improved. Particularly in this diaper 1, the channels 91 continuously extending from the front end 31 to the rear end 32 of the absorbent chassis 30 are formed in the side flaps 38 so that these channels 91 longitudinally extend through the inner space of the diaper 1. Such unique arrangement enables it to provide the diaper 1 assuring a high breathability. In this way, it is possible to prevent the humidity within the inner space of the diaper 1 from undesirably increasing and at the same time it is also possible to prevent the inner space of the diaper 1 from being filled with odor of body waste. In addition, the respective linear adhesives 90 are provided between the associated

side edges

29c, 29d of the

sheets

29a, 29b and the associated second leg elastic members 60 as viewed in the transverse direction X and therefore the first sheet 29a and the second sheet 29b of the respective side flaps 38 should not be peeled off from each other in the thickness direction W.

Additionally, as a material for the second sheet 29b adapted to form the channels 91, a thermoplastic synthetic resin having sufficiently high stiffness is used to restrict deformation of the channels 91.

Furthermore, in the central area 37, the first sheet 29a formed of a fibrous nonwoven fabric lies on the non-skin-facing side so that the non-skin-facing side of the absorbent chassis 30 provides comfortable texture. The non-skin-facing side of the second sheet 29b formed of a plastic film is covered with the first sheet 29a formed of a fibrous nonwoven fabric to prevent any foreign matter or particle from coming in direct contact with the second sheet 29b. In this way, it is possible to prevent the second sheet 29b from being perforated and it is also possible to prevent a sound from being emitted due to contact between the second sheet 29b and the foreign matter or particle.

The mass per unit area of the adhesive 90 may be set to be larger than that of the adhesive 99 to assure that the mass per unit area of the adhesive 90 in the vicinity of the side edges 29c, 29d of the first and

second sheets

29a, 29b, respectively, is larger than the mass per unit area of the adhesive 99 lying with a distance from the side edges 29c, 29d and, as a consequence, the adhesive 90 can be dimensioned to be thicker than the adhesive 99 in the thickness direction W. In this way, a clearance between the side edges 29c of the first sheet 29a and the side edges 29d of the second sheet 29b can be dimensioned relatively larger and thereby sectional areas of the respective channels 91 in the longitudinal direction Y can be dimensioned relatively larger.

In this diaper 1, the front end 31 and the rear end 32 of the absorbent chassis 30 are bonded to a region of the waist panel 10 adapted to be subjected to a contractile force of the waist elastic members 22. Consequently, front and

rear ends

91a, 91b of the respective channels 91 are located in the region of the waist panel 10 formed with gathers so that the front and

rear ends

91a, 91b of the respective channels 91 can be prevented from being closed.

In this diaper 1, furthermore, as illustrated in Figs. 1 and 2, the front cover sheet 93 adapted to cover the front end 31 of the absorbent chassis 30 is attached to the non-skin-facing side of the waist panel 10 and the rear cover sheet 94 adapted to cover the rear end 32 of the absorbent chassis 30 is attached to the non-skin-facing side of the waist panel 10. As material for these front and rear cover sheets 93, 94, melt blown nonwoven fabric treated to become hydrophobic is used. In this way, the diaper 1 assures the breathability and, at the same time, maintains the good water-impermeability.

It should be appreciated that the absorbent article may be appropriately modified without departing from the scope of this invention and not limited to the embodiment as has been described above. For example, further embodiments of the invention are not limited to the diaper 1 and applicable to the other articles such as toilet-training pants and the like. As materials for the constructional elements of the diaper 1, not only the materials described in this specification but also the materials used or to be developed in the related technical field may be unlimitedly used unless otherwise stated.

While the diaper 1 has been described hereinabove as one embodiment of this invention wherein, in the central area 37, the first sheet 29a lies on the non-skin-facing side and the second sheet 29b lies on the skin-facing side, an alternative arrangement is also possible wherein, in the central area, the first sheet 29a lies on the skin-facing side and the second sheet 29b lies on the non-skin-facing side.

As one embodiment of the invention, the diaper 1 in which only the backsheet 29 has the side flaps 38 and the front and rear end flaps 35, 36 has been described above. However, it is possible to implement further embodiments of the invention so that only the bodyside liner 28 has the side flaps 38 and the front and rear end flaps 35, 36, or both the bodyside liner 28 and the backsheet 29 have these side flaps 38 and the front and rear end flaps 35, 36. Furthermore, this embodiment has been described so that the backsheet 29 includes the first sheet 29a formed of a fibrous nonwoven fabric and the second sheet 29b formed of a plastic film. However, further embodiments of this invention are not so limited and include an alternative arrangement wherein the bodyside liner 28 includes the first sheet 29a formed of a fibrous nonwoven fabric and the second sheet 29b formed of a plastic film. Apparently another alternative is also possible in which one of the bodyside liner 28 and the backsheet 29 is formed of a fibrous nonwoven fabric to define the first sheet and the other is formed of a plastic film to define the second sheet.

In the diaper 1 according to the embodiment having been described above, the opposite side edges 29c of the first sheet 29a and the opposite side edges 29d of the second sheet 29b have respective distal ends at a same distance in the transverse direction X. It should be appreciated that it is not essential for the opposite side edges 29c of the first sheet 29a and the opposite side edges 29d of the second sheet 29b to extend inward in the transverse direction X by the same distance and the opposite side edges 29d of the second sheet 29b may extend beyond the opposite side edges 29c of the first sheet 29a in the transverse direction X and vice versa.

<Second Embodiment>
Referring to Fig. 8, a basic arrangement of a diaper 100 according to this embodiment is similar to that of the first embodiment and therefore description of this embodiment given hereunder will be limited to the features distinguishable from those of the first embodiment.

The first sheet 129a is a moisture-permeable sheet formed of a fibrous nonwoven fabric and the second sheet 129b is a liquid-impermeable sheet formed of a plastic film. One of the first and second

first sheets

129a, 129b has a dimension in the transverse direction X larger than the other, and is folded along side edges 38a of the respective side flaps 38 to define bent segments. The folded sheet is bonded, e.g., on the non-skin-facing side, to the other sheet between the bent segments and the associated side edges of the folded sheet. For example, as illustrated in Fig. 8, the first sheet 129a has a length dimension in the transverse direction X larger than a length dimension of the second sheet 129b in the transverse direction X and, along the side edges 38a of the respective side flaps 38, the first sheet 129a is bent toward the non-skin-facing side to define bent segments 196 extending outward in the transverse direction X. The folded sheet, i.e., the first sheet 129a, is bonded to the non-skin-facing side of the other sheet, i.e., the second sheet 129b, between the bent segments 196 and the associated side edges 129c of the first sheet 129a.

Between distal ends of the respective bent segments 196 of the first sheet 129a and the second sheet 129b, paired linear adhesives 190 are interposed so as to extend rectilinearly in the longitudinal direction Y. The respective linear adhesives 190 are spaced from the associated side edges 129c of the first sheet 129a in the transverse direction X toward the longitudinal imaginary center line P-P by a dimension L2 and spaced from the associated side edges 129d of the second sheet 129b in the transverse direction X away from the longitudinal imaginary center line P-P by a dimension L3, wherein these linear adhesives 190 continuously extend from the front end 31 to the rear end 32 of the absorbent chassis 30. The dimensions L2, L3 are preferably about 1 to about 10 mm and more preferably about 1 to about 5 mm. In the respective side flaps 38, between the respective linear adhesives 190 and the side edges 129c of the first sheet 129a, the first sheet 129a, the second sheet 129b and the adhesive 190 cooperate together to define the channel 191 extending in the longitudinal direction Y and opened along one side in the transverse direction X. Between the respective linear adhesives 190 and the side edges 129d of the second sheet 129b, the first sheet 129a, the second sheet 129b and the respective linear adhesives 190 cooperate together to define tubular channels 195 extending in the longitudinal direction Y. These

channels

191, 195 are formed so as to extend continuously from the front end 31 to the rear end 32 of the absorbent chassis 30.

By arranging the linear adhesives 190 in the manner as has been described above, two pairs of the

channels

191, 195 extending in the longitudinal direction Y may be formed and thereby the breathability can be further improved. Specifically, the channel 191 contributes to improve breathability in a manner similar to the channel 91 of the first embodiment. The channel 195 is in vapor communication with the inner space of the diaper 100 via the first sheet 129a which is moisture-permeable. Thus, the inner space of the diaper 100 is kept in communication with the exterior of the diaper 100 not only through the channel 191, but also through the channel 195, which further contributes to improve breathability. In this regard, however, it is not essential for the dimension L2 and the dimension L3 to be uniform along the length of the

channels

191, 195 in the longitudinal direction Y. In addition, it is possible to form the first sheet 129a from plastic film and to form the second sheet 129b from a fibrous nonwoven fabric.

<Third Embodiment>
Referring to Fig. 9, a basic arrangement of the diaper 200 according to this embodiment is similar to that of the first embodiment and therefore description of this embodiment given hereunder will be limited to the features distinguishable from those of the first embodiment.

The first sheet 229a is a moisture-permeable sheet formed of a fibrous nonwoven fabric and the second sheet 229b is a liquid-impermeable sheet formed of a plastic film. One of the first and second first sheets 229a, 229b has a dimension in the transverse direction X larger than the other, and is folded along side edges 38a of the respective side flaps 38 to define bent segments. The folded sheet is bonded, e.g., on the skin-facing side, to the other sheet between the bent segments and the associated side edges of the folded sheet. For example, as illustrated in Fig. 9, the first sheet 229a has a length dimension in the transverse direction X larger than a length dimension of the second sheet 229b in the transverse direction X and, along the side edges 38a of the respective side flaps 38, the first sheet 229a is bent toward the non-skin-facing side to define bent segments 296 extending outward in the transverse direction X. The folded sheet, i.e., the first sheet 229a, is bonded to the skin-facing side of the other sheet, i.e., the second sheet 229b, between the bent segments 296 and the associated side edges 229c of the first sheet 229a.

Between distal ends of the respective bent segments 296 of the first sheet 229a and the second sheet 229b, paired linear adhesives 290 are interposed so as to extend rectilinearly in the longitudinal direction Y. The respective linear adhesives 290 such as hot melt adhesives are spaced from the associated side edges 229c of the first sheet 229a in the transverse direction X toward the longitudinal imaginary center line P-P by a dimension L4 and spaced from the associated side edges 229d of the second sheet 229b in the transverse direction X away from the longitudinal imaginary center line P-P by a dimension L5, wherein these linear adhesives 290 continuously extend from the front end 31 to the rear end 32 of the absorbent chassis 30. The dimensions L4, L5 are preferably about 1 to about 10 mm and more preferably about 1 to about 5 mm. In the respective side flaps 38, between the respective linear adhesives 290 and the side edges 229c of the first sheet 229a, the first sheet 229a, the second sheet 229b and the linear adhesives 290 cooperate together to define the tubular channels 295 extending in the longitudinal direction Y. Between the respective linear adhesives 290 and the side edges 229d of the second sheet 229b, the first sheet 229a, the second sheet 229b and the respective linear adhesives 290 cooperate together to define the channels 291 opened along one side in the transverse direction X and extending in the longitudinal direction Y. These

channels

291, 295 are formed to extend continuously from the front end 31 to the rear end 32 of the absorbent chassis 30. The paired sets of the second leg elastic members 60 are provided between distal ends 287 and proximal ends 288 of the bent segments 296 of the first sheet 229a, respectively.

By arranging the linear adhesives 290 in the manner as has been described above, two pairs of the

channels

291, 295 extending in the longitudinal direction Y may be formed and thereby the breathability can be further improved as described with respect to the second embodiments. In this regard, however, it is not essential for the dimension L4 and the dimension L5 to be uniform along the length of the

channels

291, 295 in the longitudinal direction Y. In addition, it is possible to form the first sheet 229a of a plastic film and to form the second sheet 229b of a fibrous nonwoven fabric.

Referring to Fig. 10, a basic arrangement of an embodiment in accordance with the second aspect is similar to that of the first embodiment and therefore description of this embodiment given hereunder will be limited to the features distinguishable from those of the first embodiment.

The first sheet 329a is the moisture-permeable sheet formed of a fibrous nonwoven fabric and the second sheet 329b is the liquid-impermeable sheet formed of a plastic film. One of the first and second sheets is folded onto one of the skin-facing side and the non-skin-facing side to define bent segments, and layers of the folded sheet are bonded to each other. For example, the first sheet 329a has a length dimension in the transverse direction X larger than a length dimension of the second sheet 329b in the transverse direction X and, along the free side edges 38a of the respective side flaps 38, the first sheet 329a is bent toward the non-skin-facing side to define bent segments 396 extending outward in the transverse direction X. The opposite side edges 329c of the first sheet 329a and the associated side edges 329d of the second sheet 329b are spaced one from another by a predetermined dimension, respectively, in the transverse direction X.

Between distal ends 396a and proximal ends 396b of the respective bent segments 396 of the first sheet 329a, paired linear adhesives 390 are provided so as to bond layers of the folded sheet, i.e., the first sheet 329a, and to extend rectilinearly in the longitudinal direction Y. The respective linear adhesives 390 such as hot melt adhesives are spaced from the associated side edges 329c of the first sheet 329a in the transverse direction X toward the longitudinal imaginary center line P-P by a dimension L6 and spaced from proximal ends 400 of the associated bent segments 396 in the transverse direction X away from the longitudinal imaginary center line P-P by a dimension L7, wherein these linear adhesives 390 continuously extend from the front end 31 to the rear end 32 of the absorbent chassis 30. The dimensions L6, L7 are preferably about 1 to about 10 mm and more preferably about 1 to about 5 mm. In the respective side flaps 38, the linear adhesives 390 and the first sheet 329a cooperate together to define the channels 391 extending in the longitudinal direction Y and opened along one side thereof in the transverse direction X. The linear adhesives 390 and the first sheet 329a further cooperate together to define tubular channels 395 extending in the longitudinal direction Y. These

channels

391, 395 are formed so as to extend continuously from the front end 31 to the rear end 32 of the absorbent chassis 30. The paired sets of the second leg elastic members 60 are provided between distal ends 396a and proximal ends 396b of the bent segments 396 of the first sheet 329a, respectively.

These linear adhesives 390 make it possible to form paired sets of the

channels

391, 395 and there to improve further the breathability as described with respect to the second embodiments. In this regard, however, it is not essential for the dimension L6 and the dimension L7 to be uniform along the length of the

channels

391, 395 in the longitudinal direction Y. Furthermore, it is possible to form the first sheet 329a from a plastic film and to form the second sheet 329b from a fibrous nonwoven fabric.

(1) The first aspect of the present invention may be arranged in at least the following features:
A disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, the article comprising:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding the first sheet and the second sheet to each other and extending in the longitudinal direction from the front end to the rear end of the absorbent chassis;
wherein the first sheet, the second sheet and the adhesive cooperate together to define channels each opened along one side thereof in the transverse direction and extending in the longitudinal direction.

(2) The second aspect of the present invention may be arranged in at least the following features:
A disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, the article comprising:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding layers of one of the sheets folded onto one of the skin-facing side and the non-skin-facing side to define bent segments, the adhesive extending in the longitudinal direction from the front end to the rear end of the absorbent chassis;
wherein the folded sheet and the adhesive cooperate together to form channels extending in the longitudinal direction.

These aspects of the present invention described in (1) and (2) may include at least the following embodiments, which may be taken in isolation or in combination with one another:
(i) The annular waist panel includes an inner sheet lying on the skin-facing side, an outer sheet lying on the non-skin-facing side and elastic members interposed under tension between the inner and outer sheets so that the inner and outer sheets are subjected to a contractile force of these elastic members; and
the opposite front and rear ends of the absorbent chassis are bonded to the annular waist panel in a region adapted to be subjected to the contractile force of the elastic members.
(ii) The annular waist panel is provided on the non-skin-facing side thereof with cover sheets that cover the opposite front and rear ends of the absorbent chassis.
(iii) The absorbent chassis includes a central area defined between the side flaps in the transverse direction; and
in the central area, the first sheet lies on the non-skin-facing side and the second sheet lies on the skin-facing side.
(iv) The absorbent chassis includes an absorbent structure and a region of the absorbent chassis occupied by the absorbent structure has a cantilever bending resistance of about 15 to about 140 mm as measured in the longitudinal direction.
(v) The channels extend from the front end to the rear end of the absorbent chassis to provide communication between an inner space of the article and an exterior of the article through the channels.
(vi) The absorbent article further includes leg elastic members interposed between the first sheet and the second sheet, and bonded to the first sheet and the second sheet by a further adhesive;
wherein the adhesive defining the channels has a mass per unit area greater than the further adhesive bonding the leg elastic members.
(vii) The first sheet which lies on the non-skin-facing side is a moisture permeable sheet, and
the second sheet which lies on the skin-facing side is a liquid-impermeable sheet.
(viii) One of the first and second first sheets has a dimension in the transverse direction larger than the other, and is folded along side edges of the respective side flaps to define bent segments; and
the folded sheet is bonded to the other sheet between the bent segments and the associated side edges of the folded sheet.
(ix) The first sheet, the second sheet and the adhesive further cooperate to define tubular channels extending in the longitudinal direction from the front end to the rear end of the absorbent chassis.
(x) The folded sheet is bonded to the non-skin-facing side of the other sheet.
(xi) The folded sheet is bonded to the skin-facing side of the other sheet.
(xii) The adhesive is spaced in the transverse direction from the respective side edges of the first and second sheets by about 1 to about 10 mm.
(xiii) The adhesive is spaced in the transverse direction from the respective side edges of the first and second sheets by about 1 to about 5 mm.
(xiv) Between the adhesive and the associated side edges of the folded sheet, the adhesive and the folded sheet cooperate to define channels each opened at one side thereof in the transverse direction and extending from the front end to the rear end of the absorbent chassis to provide communication between an inner space of the article and an exterior of the article through the channels.
(xv) Between the adhesive and the bent segments of the folded sheet, the adhesive and the folded sheet cooperate to define tubular channels extending from the front end to the rear end of the absorbent chassis.
(xvi) The adhesive is spaced in the transverse direction from the respective side edge of the folded sheet by about 1 to about 10 mm.
(xvii) The adhesive is spaced in the transverse direction from the bent segment of the folded sheet by about 1 to about 10 mm.

The described aspects and/or embodiments provide one or more of the following effects:
In the disposable absorbent article according to one or more embodiments of this invention on the first aspect thereof, the first sheet, the second sheet and the linear adhesives cooperate together to define the channels opened along one side in the transverse direction and extending in the longitudinal direction so as to provide the disposable absorbent article assuring high breathability.
In the disposable absorbent article according to one or more embodiments of this invention on the second aspect thereof, the sheets and the linear adhesives cooperate together so as to form the side flaps with the channels extending in the longitudinal direction and thereby to provide the disposable absorbent article assuring high breathability.

This application claims the benefit of Japanese Application No. 2011-086828 the entire disclosure of which is incorporated by reference herein.

Claims

A disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, the article comprising:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding the first sheet and the second sheet to each other and extending in the longitudinal direction from the front end to the rear end of the absorbent chassis;
wherein the first sheet, the second sheet and the adhesive cooperate together to define channels each opened along one side thereof in the transverse direction and extending in the longitudinal direction.
A disposable absorbent article having a longitudinal direction, a transverse direction, a skin-facing side and a non-skin-facing side, the article comprising:
an annular waist panel; and
an absorbent chassis connected to the annular waist panel, wherein the absorbent chassis includes
a first sheet,
a second sheet,
opposite front and rear ends extending in the transverse direction,
a pair of side flaps extending along opposite side edges of the first and second sheets and folded onto the skin-facing side, and
an adhesive bonding layers of one of the sheets folded onto one of the skin-facing side and the non-skin-facing side to define bent segments, the adhesive extending in the longitudinal direction from the front end to the rear end of the absorbent chassis;
wherein the folded sheet and the adhesive cooperate together to form channels extending in the longitudinal direction.
The absorbent article defined by Claim 1 or 2, wherein: the annular waist panel includes an inner sheet lying on the skin-facing side, an outer sheet lying on the non-skin-facing side and elastic members interposed under tension between the inner and outer sheets so that the inner and outer sheets are subjected to a contractile force of these elastic members; and
the opposite front and rear ends of the absorbent chassis are bonded to the annular waist panel in a region adapted to be subjected to the contractile force of the elastic members.
The absorbent article defined by Claim 3, wherein the annular waist panel is provided on the non-skin-facing side thereof with cover sheets that cover the opposite front and rear ends of the absorbent chassis.
The absorbent article defined by any one of Claims 1 to 4, wherein:
the absorbent chassis includes a central area defined between the side flaps in the transverse direction; and
in the central area, the first sheet lies on the non-skin-facing side and the second sheet lies on the skin-facing side.
The absorbent article defined by any one of Claims 1 to 5, wherein the absorbent chassis includes an absorbent structure and a region of the absorbent chassis occupied by the absorbent structure has a cantilever bending resistance of about 15 to about 140 mm as measured in the longitudinal direction.
The absorbent article defined by any one of Claims 1 to 6, wherein the channels extend from the front end to the rear end of the absorbent chassis to provide communication between an inner space of the article and an exterior of the article through the channels.
The absorbent article defined by any one of Claims 1 to 7, further comprising leg elastic members interposed between the first sheet and the second sheet, and bonded to the first sheet and the second sheet by a further adhesive;
wherein the adhesive defining the channels has a mass per unit area greater than the further adhesive bonding the leg elastic members.
The absorbent article defined by any one of Claims 5 to 8, wherein
the first sheet which lies on the non-skin-facing side is a moisture permeable sheet, and
the second sheet which lies on the skin-facing side is a liquid-impermeable sheet.
The absorbent article defined by any one of Claims 1 and 3 to 9, wherein
one of the first and second first sheets has a dimension in the transverse direction larger than the other, and is folded along side edges of the respective side flaps to define bent segments; and
the folded sheet is bonded to the other sheet between the bent segments and the associated side edges of the folded sheet.
The absorbent article defined by Claim 10, wherein the first sheet, the second sheet and the adhesive further cooperate to define tubular channels extending in the longitudinal direction from the front end to the rear end of the absorbent chassis.
The absorbent article defined by Claim 10 or 11, wherein the folded sheet is bonded to the non-skin-facing side of the other sheet.
The absorbent article defined by Claim 10 or 11, wherein the folded sheet is bonded to the skin-facing side of the other sheet.
The absorbent article defined by any one of Claims 1 and 3 to 13, wherein the adhesive is spaced in the transverse direction from the respective side edges of the first and second sheets by about 1 to about 10 mm.
The absorbent article defined by any one of Claims 1 and 3 to 13, wherein the adhesive is spaced in the transverse direction from the respective side edges of the first and second sheets by about 1 to about 5 mm.