WO2013035317A1

WO2013035317A1 - Disposable wearing article

Info

Publication number: WO2013035317A1
Application number: PCT/JP2012/005614
Authority: WO
Inventors: Takaya Arayama; Hirotomo Mukai
Original assignee: Unicharm Corporation
Priority date: 2011-09-07
Filing date: 2012-09-05
Publication date: 2013-03-14
Also published as: CN103813768A; JP2013055994A; TW201325570A; AU2012305779A1; JP5848068B2

Abstract

A disposable wearing article includes an absorber includes a urinating region to be in contact with a urinating portion of the wearer, a buttock region to be in contact with buttocks of the wearer, and an absorbent sheet which has absorbent polymer sandwiched between liquid-permeable sheets. The absorbent sheet is arranged in the buttock region, but not in the urinating region. The absorber is positioned at the urinating region and has a body fluid guiding unit which extends from the urinating region towards the buttock region. The buttock region has buttock elastic members that are extensible and contractible in the longitudinal direction.

Description

DISPOSABLE WEARING ARTICLE

The present disclosure relates to a disposable wearing article.

Disposable wearing articles such as pants-type diapers with high absorption properties have recently been developed to include absorbent polymer for absorbing body fluids. For instance, Japanese Unexamined Patent Application Publication No. H08-66426 describes a disposable wearing article having a super absorbent material, such as an absorbent polymer.

This disposable wearing article has a backsheet and an absorbent structure arranged on the backsheet. The absorbent structure includes an absorption layer containing a front end and a back end, and a serge layer arranged on the absorption layer. An absorbent panel is laminated at the front end of the absorption layer, and the absorption layer and the absorbent panel are laminated at the front end of the absorbent structure, thus forming a thick front absorbent region. The absorption layer and the absorbent panel included in the front absorbent region contain the super absorbent material described above. The disposable wearing article configured as described above maintains absorption properties as a large amount of the super absorbent material is arranged at the front absorbent region that is in contact with a front side of a wearer, and thus can absorb body fluid discharged from the wearer at the front absorbent region.

[PTL 1] Japanese Unexamined Patent Application Publication No. H08-66426 (Fig. 3, Fig. 5, Paragraphs 0011, 0015, 0016, etc.)

However, the inventor(s) has/have recognized that the above-noted disposable wearing article might have the following problems.
Since a large amount of the super absorbent material is arranged at the front absorbent region, bodily fluid absorption is localized at the front absorbent region. Accordingly, the front absorbent region may become partially heavy and hang down with absorbed body fluid. This leads to the formation of a gap between the front absorbent region and the wearer's body, and side leakage, resulting in poor fit, deteriorating a feeling to wear.

Therefore, it is an object of the present invention to provide a disposable wearing article that is capable of restraining impairment of a wearing feeling or an occurrence of a leakagecaused by the absorption of body fluid, while maintaining absorbent property.

A disposable wearing article in accordance with some embodiments includes a liquid-permeable topsheet; a backsheet; an absorber that is provided between the topsheet and the backsheet and has a longitudinal direction and a widthwise direction which is orthogonal to the longitudinal direction; a urinating region that is adapted to be in contact with a wearer's urinating portion, and a buttock region that is positioned behind the urinating region and is adapted to be in contact with buttocks of the wearer; and an absorbent sheet which includes absorbent polymer sandwiched between liquid-permeable layers, and is positioned between the topsheet and the backsheet. The absorbent sheet is arranged at the buttock region but not at the urinating region. The absorber is positioned at least at the urinating region and has a body fluid guiding unit which extends from the urinating region towards the buttock region. The buttock region has buttock elastic members that are extensible and contractible at least in the longitudinal direction.

A disposable wearing article in accordance with some embodiments includes a liquid-permeable topsheet; a backsheet; an absorber that is provided between the topsheet and the backsheet and has a longitudinal direction and a widthwise direction which is orthogonal to the longitudinal direction; a urinating region that is adapted to be in contact with a wearer's urinating portion, and a buttock region that is positioned behind the urinating region and is adapted to be in contact with buttocks of the wearer. The absorber has a first region including absorbent polymer and a second region in which absorbent polymer has a lower basis weight than a basis weight in the first region. The first region is arranged at the buttock region of the absorber. The second region is arranged at the urinating region of the absorber. The absorber has a body fluid guiding unit which extends from the urinating region towards the buttock region. The buttock region has buttock elastic members that are extensible and contractible at least in the longitudinal direction.

Fig. 1 is a simplified perspective schematic view of a disposable diaper 1 according to at least one embodiment. Fig. 2 is an expansion plan view of the disposable diaper 1 . Fig. 3 is a widthwise sectional view of the disposable diaper 1, viewed along line X1-X'1 in Fig. 2. Fig. 4 is a front-back sectional view of the disposable diaper 1, viewed along line X2-X'2 in Fig. 2. Fig. 5 is a widthwise sectional view of the disposable diaper 1, viewed along line X3-X'3 in Fig. 2. Fig. 6 is a plan view of an absorber according to at least one embodiment. Fig. 7 is a sectional view along line X1-X'1, schematically illustrating the wearing state of the disposable diaper 1. Figs. 8(a), 8(b), 8(c), 8(d), 8(e), 8(f), 8(g) and 8(h) are plan views and sectional views of absorbents of disposable diapers according to various modifications. Fig. 9 is a plan view of a disposable diaper according to a modification.

Next, embodiments of a disposable diaper 1 according to the present disclosure will be described with reference to the drawings. It is to be noted that in the following description of the drawings, same or similar constituent elements are designated by same or similar reference numerals. However, it should be kept in mind that the drawings are schematic representations and are not drawn to scale unless otherwise specified. Moreover, the drawings do not necessarily reflect the actual dimensional relationships and ratios of component. Therefore, specific dimensions or the like should be determined in consideration of the following description. In addition, relations or ratios among such dimensions may be different from one drawing to another.

The disposable wearing article according to at least one embodiment has a region in which absorbent polymer for absorbing body fluid has a high basis weight, at the buttock region. The basis weight of the absorbent polymer at the region is 168g/m², for example.

(1) Overall schematic configuration of the disposable wearing article
Fig. 1 is a simplified perspective schematic view of the disposable diaper 1 that configures the disposable wearing article in at least one embodiment. Fig. 2 is an expansion plan view of the disposable diaper 1. Fig. 3 is a widthwise sectional view of the disposable diaper 1, viewed along line X1-X'1 in Fig. 2. Fig. 4 is a front-back sectional view of the disposable diaper 1, viewed along line X2-X'2 in Fig. 2. Fig. 5 is a widthwise sectional view of the disposable diaper 1, viewed along line X3-X'3 in Fig. 2. The disposable diaper 1 is, for example, a pants-type disposable diaper.

The disposable diaper 1, as illustrated in Fig. 2, has, in the longitudinal direction of the absorbent article 1, a front waistline region S1 which corresponds to the front waistline of a wearer, a back waistline region S2 that corresponds to the back waistline of the wearer, and a urinating region S3 that corresponds to the crotch portion of the wearer and is adapted to be in contact with the urinating portion of the wearer. The urinating region S3 is a region closer to the front, including the center, of the absorber in the longitudinal direction. The back waistline region S2 is a region behind the center of the absorber in the longitudinal direction, and is arranged behind the urinating region S3 and is a buttock region that is adapted to be in contact with the buttocks of the wearer.

Additionally, in case of a rectangular absorber, the front and back of the absorber are identifiable in some embodiments by coloring an absorbent sheet or by printing a front and back display on a backsheet or on a fastening tape, especially in pad-type diapers.

A front waistline edge portions 4, 4' of the front waistline region S1 are bonded to rear waistline edge portions 6, 6' of the rear waistline region S2, whereby the disposable diaper 1 is formed into the pants type.

The disposable diaper 1 has a topsheet 10, an absorber 40, sidesheets 60, a foreside exterior topsheet 70F, a backside exterior topsheet 70R, an exterior center sheet 100, a foreside exterior backsheet 80F, and a backside exterior backsheet 80R. They are bonded with an adhesive, thermal fusion bonding, or the like.

The foreside exterior topsheet 70F, the backside exterior topsheet 70R, the foreside exterior backsheet 80F, the backside exterior backsheet 80R, and the exterior center sheet 100 configure the exterior portion of the disposable diaper 1. The absorber 40 configured from cotton-like pulp and highly polymerized water absorbent polymer is provided on the inner side (skin contact surface side) of the foreside exterior topsheet 70F, the backside exterior topsheet 70R, and the exterior center sheet 100.

The topsheet 10 is a sheet that forms the skin contact surface that can be in direct contact with the skin of the wearer. The topsheet 10 is formed by a liquid-permeable sheet, such as a hydrophilic nonwoven cloth and woven cloth, an aperture plastic film, or an aperture hydrophobic nonwoven cloth. The topsheet 10 according to at least one embodiment is formed of a hydrophilic spun bond nonwoven cloth that is made of polypropylene and has the basis weight of 23 g/m².

An auxiliary sheet 15 is joined with the non-skin contact surface side of the topsheet 10. The auxiliary sheet 15 is arranged between the topsheet 10 and the absorber 40. By providing the auxiliary sheet 15, body fluid is absorbed at a faster rate and the back-flow of body fluid is prevented after absorption.

The absorber of the disposable diaper 1 of at least one embodiment is configured so as to be in close contact with the crotch portion of a wearer, thereby improving comfort after excretion by restraining the body fluid from flowing back after absorption. For the auxiliary sheet 15, for instance, an air-through nonwoven cloth, an aperture film, or the like is used. The auxiliary sheet 15 of at least one embodiment is formed of an (hydrophilic) air-through nonwoven cloth of 50 g/m².

The absorber 40 is arranged between a composite sheet in which the topsheet 10 and the auxiliary sheet 15 are bonded together, and an absorber backside covering sheet 30 (as a backsheet). The absorber 40 has the longitudinal direction from the front waistline region S1 towards the back waistline region S2, and the widthwise direction W that is orthogonal to the longitudinal direction . The absorber 40 has an inward direction IN towards a wearer of the disposable diaper 1, and an outward direction OUT towards the direction opposite to the inward direction. The absorber 40 is formed of the mixed powder of ground pulp, highly absorbent polymer, and the like.

The absorber 40 is configured of a first layer 41 arranged at the non-skin contact surface side of a wearer, and a second layer 42 that is laminated on the first layer 41 and is at the skin contact surface side of the wearer. A central aperture 45 is formed at the center of the first layer 41 of the absorber 40 in the widthwise direction W. A pair of first side slits 46 are formed on both outer sides in the widthwise direction of the central aperture 45. The configuration of the absorber 40 will be explained below in detail. The central aperture and the first side slits function as a curving unit which will be described below, and also as a body fluid guiding unit.

An absorbent sheet 90 is arranged at the skin contact surface side of the absorber in the back waistline region. The absorbent sheet is arranged behind the auxiliary sheet 15. The absorbent sheet is a composite sheet which includes absorbent polymer to hold body fluid at the back waistline region and prevent the body fluid held at the absorber from returning toward the wearer. The configuration of the absorbent sheet will be explained below in detail.

The absorbent article 1 has a central elastic member 44 that is arranged so as to overlap the central aperture 45 in the thickness direction T of the absorbent article 1.

As a result of the elastic members and slits formed in the absorber 40, the absorber 40 is configured to curve when the disposable diaper 1 is worn. In at least one embodiment, the central elastic member 44 and the central aperture 45 configure the central curving unit, and the first side slits 46 configure the first curving units.

Sidesheets 60 are arranged on both ends in the widthwise direction W of the absorber 40 so as to wrap the topsheet 10 and the absorber backside covering sheet in one body. The sidesheets 60 are formed of a sheet such as a liquid-impermeable nonwoven fabric. The sidesheets 60 of at least one embodiment are the polypropylene SMS (spunbond-meltblown-spunbond) nonwoven cloth of 15 g/m².

Both the sidesheets overlap at the end in the widthwise direction of the sidesheets 60. At the sections where the sidesheets overlap each other, leakage-preventing elastic members 53 (see Fig. 3) are provided in an extended state along the longitudinal direction. A leakage-preventing wall is configured of the sidesheet 60 and the leakage-preventing elastic member 53 for preventing the side leakage of body wastes.

The leakage-preventing walls are provided along the longitudinal direction of the absorbent article 1 on both ends in the widthwise direction of the absorber 40. A plurality of the leakage-preventing elastic members 53 are provided, between the folded-down sidesheets 60, along the longitudinal direction of the absorbent article 1 in an extended state in the longitudinal direction of the absorbent article 1.

Spandex is used for the leakage-preventing elastic members 53 of at least one embodiment, and every group of two elastic members is extended and fixed at left and right with a thickness of 780 dtex and 3.0 times in extension magnification. The sidesheets 60 are fixed to the non-skin contact surface side of the absorber backside covering sheet and are folded down towards the topsheet from both ends in the widthwise direction of the absorber. The sidesheets 60 are fixed to the topsheet 10 with a plurality of lines of hot-melt adhesive in the weight of 0.1 g/m by a bead coating.

An exterior topsheet has the foreside exterior topsheet 70F arranged at the front waistline region S1, and the backside exterior topsheet 70R arranged at the back waistline region S2. In the thickness direction T, the foreside exterior topsheet 70F is arranged between the foreside exterior backsheet 80F and the absorber 40. In the thickness direction T, the backside exterior topsheet 70R is arranged between the backside exterior backsheet 80R and the absorber 40. In the longitudinal direction , the exterior center sheet 100 is arranged between the foreside exterior topsheet 70F and the backside exterior topsheet 70R.

The front end of the exterior center sheet 100 is joined with the back end of the foreside exterior topsheet 70F, and the back end of the exterior center sheet 100 is joined with the front end of the backside exterior topsheet 70R. The exterior center sheet 100 is arranged to straddle the foreside exterior topsheet 70F and the backside exterior topsheet 70R. The exterior center sheet 100 is joined to the surface of the exterior topsheets by continuously coating a hot-melt adhesive using a slot coater.

The exterior center sheet 100 is configured of a nonwoven fabric or the like. The exterior topsheet of at least one embodiment is configured of a polypropylene SMS nonwoven cloth having the basis weight of 15 g/m². The exterior center sheet 100 is positioned inside the exterior topsheet (skin contact surface side) at diaper wearing state.

The foreside exterior topsheet 70F and the backside exterior topsheet 70R are formed wider than the urinating region S3 in the widthwise direction W at the front waistline region S1 and the back waistline region S2. The foreside exterior topsheet 70F and the backside exterior topsheet 70R can be formed by an air-through nonwoven cloth, a spun bond nonwoven cloth, an SMS nonwoven cloth, or a water-resistive film. The exterior topsheet of at least one embodiment is configured of a polypropylene SMS nonwoven cloth having the basis weight of 15 g/m².

The foreside exterior backsheet 80F is provided towards the non-skin contact surface side closer than the foreside exterior topsheet 70F at the front waistline region S1. The backside exterior backsheet 80R is provided towards the non-skin contact surface side closer than the backside exterior topsheet 70R at the back waistline region S2. One end of the foreside exterior backsheet 80F (backside exterior backsheet 80R) in the longitudinal direction is folded towards the skin contact surface side so as to cover the end in the longitudinal direction of the foreside exterior top sheet 70F (backside exterior topsheet 70R).

The foreside exterior backsheet 80F and the backside exterior backsheet 80R may be formed of an air-through nonwoven cloth, a spun bond nonwoven cloth, an SMS nonwoven cloth, a water-resistive film, or the like. The foreside exterior backsheet 80F and the backside exterior backsheet 80R of at least one embodiment are configured of a polypropylene spun bond nonwoven cloth having the basis weight of 17 g/m².

The absorber backside covering sheet 30 is partially bonded to the foreside exterior top sheet 70F, the backside exterior topsheet 70R, and the exterior center sheet 100.

Waist gathers 3 are provided at the front waistline region S1 and the back waistline region S2. The waist gathers 3 have an elongated waist elastic member 3A of synthetic rubber, for example, that is laid out to extend and contract along the widthwise direction W of the absorber 40. The waist elastic member 3A is joined between the foreside exterior top sheet 70F and the foreside exterior backsheet 80F, and between the backside exterior topsheet 70R and the backside exterior backsheet 80R with an adhesive (for instance, hot-melt adhesive) in the extended state in the widthwise direction W of the disposable diaper 1.

As a waistline elastic member is arranged, the disposable wearing article can be held up around the waistline without hanging down as a whole. Therefore, body fluid is kept at the absorbent sheet 90 as described below, thereby preventing the absorber from hanging down and also restraining a gap from being formed between the absorber 40 and a wearer's body even when the back side of the absorber becomes heavy due to the absorbed body fluid.

The waist gathers 3 continue from one front waistline edge 4 to another front waistline edge 4' of the absorbent article 1 in the front waistline region S1, and continue from one back waistline edge 6 to another back waistline edge 6' of the absorbent article 1 in the back waistline region S2.

The backside exterior backsheet 80R is formed with leg gathers 5. The leg gathers 5 are formed along the legs of a wearer. The leg gathers 5 are formed to run along the leg portions of the wearer. The leg hole elastic members include a front leg hole elastic member 5F arranged at the front waistline region S1 and a back leg hole elastic member 5R arranged at the back waistline region S2. The leg gathers 5 are provided so as not to cross (or overlap) the absorber 40.

The leg hole elastic members function as buttock elastic members that prevent the back waistline region S2 (as the buttock region at the absorbent sheet 90) from hanging down as described below. When body fluid concentrates on the absorbent sheet 90, the back waistline region S2 where the absorbent sheet 90 is arranged is likely to fall downward. However, the leg hole elastic members, which are extensible and contractible at least in the longitudinal direction, are arranged outboard of the absorbent sheet in the widthwise direction, thus preventing the back waistline region S2 from hanging down. Based on this view, the leg hole elastic members are arranged in some embodiments around the front end of the absorbent sheet 90.

Additionally, the buttock elastic members are configured in some embodiments so as to extend and contract in the longitudinal direction before being worn by a wearer. For example, in a state of being worn by the wearer, a portion of the absorber 40 arranged at the back waistline region S2 is oriented in the top and bottom direction while it is oriented in the longitudinal direction before being worn. Therefore, the buttock elastic members extend and contract in the top and bottom direction after being worn by a wearer, preventing the back waistline region S2 from hanging downward.

The buttock elastic members are sufficiently configured in some embodiments to extend and contract at least in the longitudinal direction. The buttock elastic members are configured in some embodiments to be elastic not only in the longitudinal direction but also in the widthwise direction. For instance, the material may be an elastic member that extends and contracts in an oblique direction relative to the longitudinal direction and that has an elastic component in the widthwise direction and an elastic component in the longitudinal direction. Thus, the material may be arranged oblique to the longitudinal direction in some embodiment, or may be arranged along the longitudinal direction in further embodiments.

The leg hole elastic members are joined between the foreside exterior topsheet 70F and the foreside exterior backsheet 80F, and between the backside exterior topsheet 70R and the backside exterior backsheet 80R.

Three of the leg hole elastic members of at least one embodiment are fixed in an extended state at the thickness of 780 dtex and 1.5 to 3.5 times in extension magnification. The leg hole elastic members are arranged at each portion with a different grade in magnification.

The leg hole elastic members are fixed with the hot melt adhesive already coated on the exterior topsheet. The hot melt adhesive is coated by a spiral spray. The coating weight of the leg hole elastic members is 7 g/m². An adhesive is coated by a slot coater at a location where the vicinity of the exterior topsheet ends (at about 5 mm from the ends) overlaps at least the leg hole elastic member. With this adhesive coating, the leg hole elastic members are prevented from hanging down out from the ends of the exterior surface sheet.

When an adhesive is coated by a non-contact type spiral spray, the adhesive near the ends of the exterior topsheet may protrude, causing manufacturing problems. However, an adhesive may be prevented from protruding by coating using a contact type slot coater. The coating weight of the slot coater is 10 g/m².

The central elastic member 44 is arranged along the longitudinal direction so as to overlap the central aperture 45 in the thickness direction T of the disposable diaper 1. The central elastic member 44 is formed so as to overlap the absorber 40 in the longitudinal direction, allowing the absorber 40 to curve and project towards the inward direction IN; in other words, to curve and project towards a wearer. The central elastic member 44 is arranged in an extended state along the longitudinal direction at the center in the widthwise direction of an absorbent article. The central elastic member 44 is arranged at the urinating region S3.

The central elastic member 44 is provided between an elastic member covering sheet 43 and an absorber backside covering sheet 30 in an extended state. The central elastic member 44 is arranged at the extension magnification of 1.4 to 3.0 times. The central elastic member of at least one embodiment has central elastic members at the center in the widthwise direction, and central auxiliary elastic members arranged outboard of the central elastic members in the widthwise direction.

The central elastic members are arranged at the extension magnification of 1.4 to 3.0 times. Three of the center elastic members of at least one embodiment are fixed in an extended manner at the thickness of 620 dtex and 2.5 times in extension magnification. The central elastic members have a 5 mm gap therebetween, and adhesion lengths are all 120 mm. The central auxiliary elastic members are arranged at the stress of 1.2 to 2.5 times which is lower than the stress at the central elastic members. Every one of the central auxiliary elastic members of at least one embodiment is extended and fixed with a thickness of 620 dtex and 1.8 times in extension magnification. From both ends of the central elastic members, the central auxiliary elastic members are arranged with a 5 mm gap at the same locations in the longitudinal direction as the central elastic members with a gap of 5 mm in the widthwise direction from both ends of the central elastic members.

The central elastic member 44 is spandex, and hot melt adhesive is coated therefor by a V-slot method. An elastic nonwoven fabric may be used for the central elastic member 44. The elastic member covering sheet 43 is configured of a sheet such as nonwoven fabrics. In at least one embodiment, a (hydrophilic) SMS nonwoven cloth made of polypropylene and having the basis weight of 15 g/m² was used.

Examples of the material of the central elastic member 44 include synthetic rubber such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, elastic polyolefin, spandex, and foamed polyurethane. Additionally, the material of the central elastic member 44 may include elastic sheets, such as elastic nonwoven fabric formed by mixing elastomer fibers of urethane, polystyrene or the like with stretchable thermoplastic fibers of polyolefin, polyester or the like and then by drawing processing.

A side end elastic member 49 is joined between the absorber backside covering sheet 30 and the sidesheet 60 on both sides in the widthwise direction of the absorber with an adhesive. The side end elastic member 49 is arranged along the longitudinal direction , straddling the urinating region S3 and one portion of the back waistline region S2.

The side end elastic member 49 is fixed with hot melt adhesive or the like. Spandex is used for the side end elastic member 49 of at least one embodiment, and hot melt adhesive is directly coated by a V-slot method. Every group of three side end elastic members 49 of at least one embodiment is extended and fixed at a thickness of 780 dtex and the extension magnification of 2.3 times on both right and left sides.

Moreover, the side end elastic members 49 and the front leg hole elastic members 5F, and the side end elastic members 49 and the back leg hole elastic members 5R are arranged roughly in a row in the plan view. By this arrangement, the materials can extend and contract around leg holes, thereby making leg holes more fitting and preventing a diaper from slipping off or leaking.

Note that the extension stress of the elastic members can be measured as described below, for example.
(1) A material including sandwiched elastic members is cut out so as to include all the elastic members which form the projecting convex portion, in the widthwise direction. Specifically, for example, for the worn article relating to at least one embodiment, a material having sandwiched central elastic members - every group of three of which were positioned with a gap of 5 mm therebetween - is extended without sagging, and is then cut out at 13 mm in width times 100 mm in length. In the same extended state, the material is marked at each 10 mm inner side from both ends in the longitudinal direction. For the measurement of extension stress, a tensile testing machine by Instron Japan Company, Ltd. (for instance, Model: 5564), or Autograph manufactured by Shimadzu Corporation (for instance, Model: AGS-1kNG) was used.

(2) The test sample of (1) is held with a top chuck so as to let one marking be at the inner end of the chuck and also with a bottom chuck so as to let the other marking be at the inner end of the chuck. The length of the test sample between the chucks is 80 mm. Note that when the effective length of the gathers of the elastic members is shorter than 100 mm, the length that is 20 mm shorter than the shortest length in the effective length of the gathers of the elastic members is set as the length of the test sample between the chucks. In order not to add tension initially to the test sample, the initial distance between the chucks is set shorter than the shrunk length (natural length) of the test sample. In order to alienate the chucks from each other, the test sample is pulled up and down under a condition of 100 mm/min, and the test sample is extended.

(3) The test sample is extended until the sample length between the chucks would be 90%, based on that the sample length between the chucks is 100% when the material sandwiching the elastic members is extended without sagging, and then the stress is measured during the sample extension process and is considered as the extension stress of the elastic members. That is, in the above embodiment, the extension stress when the test sample is extended up to 72 mm, which is 90% of 80 mm - the 100% length of the text sample, is measured.

The thickness of the absorber 40 is measured by sandwiching a measuring portion into a thickness gauge while the absorber 40 is in a stretched state in the lengthwise and widthwise direction (in other words, in a flat condition without wrinkles). A thickness gauge manufactured by PEACOCK (measurement part: 5-mm diameter, pressure at the time of measurement: 163 g/cm²) can be used as the measurement device, for example.

As for each member configuring the aforementioned disposable diaper 1, the material described in Japanese Unexamined Patent Publication No. 2006-346439, which is incorporated by reference herein in its entirety, may be used.

(2) Configuration of Absorbent Sheet
Subsequently, the absorbent sheet 90 arranged on the skin contact surface side of the absorber 40 at the back waistline region S2, will be explained. The absorbent sheet 90 is a composite sheet which includes an absorbent polymer 91 sandwiched between at least two liquid-permeable layers, e.g., liquid-

permeable sheets

92 and 93. For the liquid-

permeable sheets

92 and 93, for instance, nonwoven fabrics are used. Additionally, an absorbent sheet may be prepared by sandwiching the absorbent polymer 91 with three or more liquid-permeable sheets, or by sandwiching the absorbent polymer with one folded-up liquid permeable sheet.

The absorbent polymer 91 is a polymer which absorbs water, for instance an absorbent polymer having a three-dimensional mesh structure in which water-insoluble polymers are adequately cross-linked. Although such an absorbent polymer absorbs water by several hundred to a thousand times in volume in comparison with the volume before the water is absorbed, it is essentially water insoluble. Once water is being absorbed, the water is unlikely released even with some added pressure.

The absorbent polymer 91 includes, for example, starch based, acrylic acid based or amino acid based polymer in a particle or fiber shape. After the absorbent polymer 91 is sandwiched between two liquid-

permeable sheets

92 and 93, the two liquid-

permeable sheets

92 and 93 are joined, thus forming the absorbent sheet 90. In some embodiments, after the absorbent polymer 91 is sandwiched between the two liquid-

permeable sheets

92 and 93, the absorbent polymer 91 has a particle diameter which is not as fine as a gap between the fibers of the liquid-

permeable sheets

92 and 93 in order to prevent the absorbent polymer 91 from falling off.

For the liquid

permeable sheets

92, 93, e.g., a spun bond nonwoven cloth, a point bonded nonwoven cloth, an air-through nonwoven cloth, a SMS nonwoven cloth, etc., may be used. The liquid-

permeable sheets

92 and 93 have permeability for urine, so that, in some embodiments, the sheets are treated with a hydrophilic treatment. In at least one embodiment, an air-through nonwoven cloth of 25 g/m² treated with a hydrophilic treatment was used as the liquid-

permeable sheets

92 and 93.

The liquid-

permeable sheets

92 and 93 have a plurality of adhesive regions (not shown) that extend in the longitudinal direction and are positioned in parallel in the widthwise direction at the surfaces for sandwiching the absorbent polymer 91. The adhesive regions may be provided at one of the surfaces for sandwiching the absorbent polymer 91 of the liquid-

permeable sheets

92 and 93. The adhesive regions are formed by, for instance, coating a hot melt adhesive in lines.

As a result, the absorbent polymer 91 is fixed to the liquid-

permeable sheets

92 and 93. The adhesive regions extend in the longitudinal direction and are lined up in plurality in the widthwise direction, in other words, the adhesive regions are in a stripe pattern. This is because the permeability of urine is likely to decrease at the adhesive regions, and a region with no adhesive is provided to ensure sufficient urine permeability. As long as a coating method can provide a region with no adhesive , specifically, as long as a coating method can provide intermittently the adhesive regions, the method is not limited only to a stripe-pattern coating method but to a non-contact coating method such as an omega coating.

As the adhesive regions are provided intermittently at an absorbent polymer containing region 96 described below, the absorbent polymer 91 is prevented from concentrating in the absorbent polymer containing region 96. A distance between the adjacent adhesive regions provided at the liquid-permeable sheet 93 on the side of the absorber 40 is smaller than a distance between the adjacent adhesive regions provided at the liquid-permeable sheet 92 at the topsheet 10 side. Thus, the absorbent polymer is evenly fixed to the liquid-permeable sheet 93 on the side of the absorber 40.

By providing the stripe-pattern adhesive regions colored in blue or the like to the liquid-

permeable sheets

92 and 93, a blue stripe pattern is added to the absorbent article 1 and the appearance of the absorbent article 1 improves. Furthermore, the adhesive regions may be provided only to the surface which sandwiches the absorbent polymer, of the liquid-permeable sheet 93 on the side of the absorber 40. By providing the adhesive regions to the liquid-permeable sheet 92 and/or 93, the absorbent polymer is prohibited from shifting within the absorbent sheet 90 before the polymer swells up. In some embodiments, the absorbent sheet 90 is arranged at least in the back waistline region S2.

Thus, by arranging the absorbent polymer locally at the back waistline region S2, an absorption capability at the back waistline region S2 would improve, and leakage from the back waistline region which mostly occurs from sitting and sleeping would be reduced.

In the absorbent sheet 90, the absorbent polymer is arranged separately in a plurality of absorbent polymer containing regions 96, and a region 97 with no absorbent polymer (referred to as absorbent polymer non-containing region hereinafter) is arranged between each pair of the adjacent absorbent polymer containing regions 96. Fig. 2 illustrates the absorbent polymer containing regions 96 with diagonal lines.

By alternately providing polymer containing regions and a polymer non-containing region, urine passes through the absorbent polymer non-containing region 97 and is absorbed by the absorber 40 even when the absorbent polymer of the absorbent polymer containing regions 96 absorbed urine and swelled up with no further absorption capacity. Additionally, for an absorbent article which does not have to be in use until the absorbent polymer swells up, it is unnecessary to provide the absorbent polymer non-containing region for the absorbent sheet.

The plan shape of an absorbent polymer containing region 96 is convex from the front waistline region S1 towards the back waistline region S2 in the longitudinal direction of the absorbent article 1, and is roughly a V-shape which extends in the widthwise direction of the absorbent article 1. Specifically, the plan shape of an absorbent polymer containing region 96 is roughly a V-shape where the apex is directed rearwardly from the front waistline region S1 and pointed to the back waistline region S2 in the longitudinal direction of the absorbent article 1. However, the absorbent polymer containing region 96 that is furthest apart from the front waistline region S1, is roughly in a V-shape or an arc-shape with two separate portions split in half at the center of the article in the widthwise direction. The roughly V-shape of the absorbent polymer containing regions 96 matches the buttocks of a wearer, so that the absorbent polymer containing regions 96 fit the buttocks of a wearer and a space between the wearer and the absorbent article 1 is unlikely to form. Additionally, when there is an absorbent polymer non-containing region, the shape of the absorbent polymer containing regions is not limited to a roughly V-shape. For instance, the absorbent polymer containing regions may be in the shape of arc, circle, rectangle, triangle, and the like.

As described above, the absorbent sheet 90 is prepared by joining the two liquid-

permeable sheets

92 and 93 after the absorbent polymer is sandwiched between the two liquid-

permeable sheets

92 and 93. The region where the absorbent polymer is sandwiched between the two liquid-

permeable sheets

92 and 93 is an absorbent polymer containing region 96. The region which has no absorbent polymer sandwiched between the two liquid-

permeable sheets

92 and 93 and where the two liquid-

permeable sheets

92 and 93 are joined together, is an absorbent polymer non-containing region 97.

The bonding of the two liquid

permeable sheets

92, 93 is strong enough to resist expansion power from the swelling of the absorbent polymer. For instance, when the two liquid-

permeable sheets

92 and 93 peel off from each other due to the swelling of the absorbent polymer, a gap is formed between the two liquid-

permeable sheets

92 and 93 and the absorbent polymer comes into the gap, so that the absorbent polymer non-containing region 97 is not always formed. For the bonding of the liquid-

permeable sheets

92 and 93, heat seal, sonic seal, adhesives, or the like may be used.

As a linear pressure in the widthwise direction of the heat seal becomes more constant in joining the liquid-

permeable sheets

92 and 93 with the heat seal, sealing strength becomes even as a whole. Therefore, in some embodiments, a linear load in the widthwise direction of the heat seal is constant. In order to make a linear load in the widthwise direction of heat seal constant, the total length in the widthwise direction of a region to be sealed is made constant. For instance, as described above, the absorbent polymer containing regions 96 are shaped roughly in a V-shape or an arc-shape and are arranged in the longitudinal direction, so that an absorbent polymer non-containing region 97 has nearly a constant total length in the widthwise direction. In joining the liquid-

permeable sheets

92 and 93 together with an adhesive, the liquid-

permeable sheets

92 and 93 are wet when the absorbent polymer is swollen. Therefore, in some embodiments, an adhesive that is strong even when the sheets are wet is used.

Since the absorbent polymer swells up after urine absorption, the absorbent polymer in some embodiments has enough capacity to swell up between the two liquid-

permeable sheets

92 and 93 at the absorbent polymer containing region 96. If the absorbent polymer is filled between the two liquid-

permeable sheets

92 and 93 too densely, the absorbent polymer would not be able to swell fully, so that the absorption capacity of absorbent polymer may not be fully utilized.

When more absorbent polymer containing regions 96 are provided at the absorbent sheet 90, the area of the absorbent polymer non-containing region 97 increases. However, as the total capacity of the absorbent polymer at the absorbent sheet 90 becomes small, the amount of urine to be absorbed by the absorbent sheet 90 decreases. On the other hand, when fewer absorbent polymer containing regions 96 are provided at the absorbent sheet 90, the total capacity of the absorbent polymer at the absorbent sheet 90 becomes large and the amount of urine to be absorbed by the absorbent sheet 90 increases. However, the area of the absorbent polymer non-containing region 97 becomes small, and urine is difficult to permeate through the absorbent sheet 90 to be absorbed by the absorber 40 after the absorbent polymer swells up.

In some embodiments, the number of absorbent polymer containing regions 96 is selected in consideration of a balance between the amount of urine and the permeability of urine at the absorbent sheet 90 after the absorbent polymer is swollen, and also of urine permeability after the swelling based on the kinds and input amounts of the absorbent polymer. For instance, when the absorbent sheet is 180 mm times 130 mm in size, 2 g of absorbent polymer which absorbs 60 g of physiological salt solution per 1 g, is arranged separately at five absorbent polymer containing regions, thus providing an absorbent sheet having a preferable balance between urine absorption properties and urine permeability after the absorbent polymer is swollen.

The absorbent sheet 90 may be arranged on the non-skin contact surface side of the absorber 40, but it is preferable to arrange the absorbent sheet on the skin surface side thereof. When a wearer is in a sitting or sleeping position, the urine absorbed by the absorber 40 at the back waistline region S2 seeps out as pressure from weight (body pressure) is added to the absorber 40. However, the absorbent sheet 90 makes it hard to let the seeping urine touch the skin of a wearer. Since the absorbent sheet 90 is mostly made of absorbent polymer, urine hardly seeps out even with added body pressure. Thus, even after urine is released, the skin of a wearer remains dry without causing irritation to the skin of the wear resulting from the released urination.

Additionally, with the lift-up effect of the leg hole elastic members, the absorbent sheet 90 stays in contact with skin even when the absorbent sheet 90 absorbed liquid and became heavy. Accordingly, a gap between the absorber and skin is unlikely to form, so that leakage particularly through the surface of skin is decreased. In a configuration where the absorber is made so as not to be apart from skin, skin is likely to become irritated especially when the body fluid seeping from the absorber 40 can reach the skin of the wearer easily. Therefore, it is more preferable to arrange the absorbent sheet 90 on the skin surface side of the absorber 40.

(3) Structure of Absorber
Fig. 6 is a plan view of the absorber 40. As shown in Fig. 6, the absorber 40 has the first layer 41 and the second layer 42 laminated on the first layer 41. The first layer 41 is positioned at the non-skin contact surface side of the wearer, and the second layer 42 is positioned at the skin contact surface side of the wearer.

The first layer 41 and the second layer 42 are configured by cotton-like pulp and highly polymerized absorbent polymer (SAP). The absorber 40 is formed by mixing, for instance, 0 to 500 g/m² of the pulp and 0 to 500 g/m² of SAP.

The first layer 41 of at least one embodiment is formed by mixing 280 g/m² of the pulp and 170 g/m² of SAP, and the thickness thereof is about 3.1 mm. The second layer 42 of at least one embodiment is formed by mixing 260 g/m² of the pulp and 160 g/m² of SAP, and the thickness thereof is about 2.9 mm. Thus, the thickness of the absorber 40 is 6.0 mm.

The first layer 41 is formed with the central aperture 45 and a pair of the first side slits 46. The central aperture 45 is formed at the center in the widthwise direction W. The central aperture 45 and the first side slits 46 have an elongated shape which extends along the longitudinal direction. The central aperture 45 and the first side slits 46 are formed at the urinating region S3, extending in the longitudinal direction, and function as body fluid guiding units for guiding the body fluid absorbed by the absorber 40 of the urinating region S3 to the absorbent sheet 90 at the back waistline region S2.

The back end of the central aperture 45 may be arranged so as to overlap the absorbent sheet 90, or may be arranged adjacent to the absorbent sheet without overlapping the absorbent shet. Also, the absorbent sheet may be arranged on an extension line that extends towards the back of the central aperture.

By arranging the central aperture and the absorbent sheet as described above, the center portion of an absorber is easily curved towards the skin of a wearer. Moreover, the liquid absorbed by the absorber through the central aperture 45 and the first side slits 46 can be smoothly guided to the back waistline region S2 through the central aperture, etc. By guiding the body fluid to the absorbent sheet 90 at the back waistline region S2, the body fluid can be localized to the portions with high absorption capability.

Thus, by effectively utilizing absorbent capacity, the absorption capability of an absorbent article as a whole will improve. Moreover, when discharged urine is held mostly at the crotch portion, the absorber bulges out at the crotch portion, so that a wearer would have a hard time closing the legs, i.e., a major discomfort making walking difficult. However, by guiding urine away from the urinating region towards the absorbent sheet and holding the urine mostly there, absorption efficiency can improve and leakage can be reduced while decreasing the discomfort caused by a thickened absorber due to an expansion of the absorbent polymer after the absorption of urine at the crotch portion.

There is also a distance of about 10 mm in a plan view between an absorbent polymer containing region 96 and the central aperture 45. A gap between the absorbent polymer containing region 96 and the back end of the central aperture 45 is mentioned as an intermediate region 110 herein. The intermediate region 110 is configured to spread body fluid so as to localize the fluid at the absorbent polymer containing region 96 even when urination is repeated. Based on this standpoint, the weight ratio of the absorbent polymer at the intermediate region is below 80%. At the intermediate region of at least one embodiment, the weight ratio of the absorbent polymer is 38%.

The body fluid guiding units of at least one embodiment include apertures such as slits formed at the absorber, but are not limited to this configuration. The body fluid guiding units may be formed of, for instance, a low basis weight region having a lower basis weight than the basis weight of the surrounding region at the absorber, or a compressed portion compressed in the thickness direction of the absorber. In some embodiments, the body fluid guiding units which are formed of regions with a low basis weight are better than body fluid guiding units which are formed of a compressed portion in a sense that passages for fluid are not blocked even after repeated fluid absorption, since the basis weight of the absorbent polymer at the low basis weight region is lower than the basis weight of the absorbent polymer at the compressed portion.
However, in further embodiments, the body fluid guiding units configured of compressed portions are superior in that the compressed portions have a high density and thus have excellent diffusibility, so that the compressed portions can spread fluid well even in the direction against gravity better than the body fluid guiding units with a low basis weight region.

The low basis weight regions in some embodiments of the present invention include a region having a basis weight at the ratio of less than 50% in comparison with the average basis weight at the surrounding region that surrounds the low basis weight region. The basis weight can be measured by, for instance, the following method. First, at the target region of a product, the topsheet is marked at the size of 10 mm wide and 50 mm long. The absorber is cut out at the above-mentioned size for every sheet member, and its initial weight is measured. This weight is mentioned as A (g).

Subsequently, the sheet members (topsheet, auxiliary sheet, backside covering sheet, etc.) that were cut out altogether are washed with an organic solvent such as toluene, and are dried. Then, the weights are measured so as to find the total weight of the sheet members. This weight is referred to as B (g).

The basis weight of the absorber is calculated from "(A - B) / Sampling size" with the initial weight (A) and the weight (B) of sheet members. Specifically, the basis weight of at least one embodiment can be calculated from (A - B)/ (10 times 50/1000/1000) (g/m²). The above-noted weight is the weight including hot melt adhesive, but the adhesive weighs much less than the absorber, etc., so that the weight of adhesive may be ignored.
A basis weight ratio is calculated in accordance with the basis weight of the absorber found in the above-noted method.
Basis Weight Ratio = (Basis Weight of Absorber at Low Basis Weight Region)/ (Basis Weight of Absorber at Surrounding Region) times100
The low basis weight region is the region having the basis weight ratio below 50%.
In other words, the region which meets the following condition is identified as the low basis weight region.
(Basis weight of the absorber in the low basis weight region) / (Basis weight of the peripheral absorber) times 100 =50 (%) or (Basis weight of the absorber in the low basis weight region) / (Basis weight of the peripheral absorber) times 100 <50 (%).

When the low basis weight region is at a location where other absorption layers are not overlapping (for instance, a region that is formed with the first absorption layer 41 but is not covered with the second absorption layer 42), the basis weight of the absorption layer at the targeted low basis weight region and the basis weight of the absorption layer at the surrounding region are calculated from the method mentioned above.

When the low basis weight region is at a location where other absorption layers are overlapping (for instance, a region that is formed at the first absorption layer 41 and is covered with the second absorption layer 42), it is difficult to measure the basis weight of one absorption layer at the low basis weight region. Therefore, the basis weight of the low basis weight region is measured by calculating the basis weight X1 of an overlapping portion of the absorption layers at the targeted low basis weight region, the basis weight X2 of a surrounding region of the absorber, and the basis weight X3 of a single layer portion that is not overlapping.

Furthermore, in this case, when (1) the absorption layer having the low basis weight region is the single layer mentioned above, the low basis weight region can be expressed by (X1 - X2 plus X3) / X3 times 100 = 50 (%) or (X1 - X2 plus X3) / X3 times 100 < 50 (%).
On the other hand, when (2) the absorption layer having the low basis weight region is not the single layer mentioned above, the low basis weight region can be expressed by (X1 - X3) / (X2 - X3) times 100 = 50 (%) or (X1 - X3) / (X2 - X3) times 100 < 50 (%).
Specifically, depending on the structure of the low basis weight region, the basis weight can be found by the aforementioned three methods.

Additionally, as the central aperture 45 is formed, a center portion 40C can be easily curved and protruded in the inward direction IN towards a wearer. The first side slits 46 are formed outboard of the central aperture 45 in the widthwise direction. The first side slits 46 have an elongated shape which extends along the longitudinal direction. A pair of the first side slits 46 is formed in the absorber 40 along the longitudinal direction so as to curve and project the absorber 40 in the outward direction OUT, in other words, in the opposite direction to the projecting direction of the central aperture 45.

The second layer 42 is roughly in an hourglass shape. The second layer crosses over a boundary between the back waistline region S2 and the urinating region S3, and has boundaries 40b in the direction toward the inner direction of the widthwise direction between an overlapping portion and a non-overlapping portion therewith towards the urinating region in the longitudinal direction. The overlapping portion 40e is an area where the first layer 41 and the second layer 42 are laminated. The overlapping portion 40e has a higher flexural rigidity than the non-overlapping portion 40n, so that a deformation that is generated by the first side slit in the urinating region and that curves in the outward direction OUT is not conveyed beyond the boundary portion between the overlapping portion of the first layer and the non-overlapping portion thereof.

In some embodiments, the width of the absorber is 120 mm to 250 mm at the front waistline region S1 and the back waistline region S2, and 120 mm to 250 mm at the urinating region S3.

The central aperture 45 in the longitudinal direction is longer than the first side slits 46 in the longitudinal direction. In at least one present embodiment, the central aperture is 40 mm wide and the first side slits 46 are 10 mm wide respectively.

At the urinating region S3, the outside ends 42W in the widthwise direction of the second layer 42 overlap the inside ends 41W of the first side slits 46 of the first layer, and are positioned along the longitudinal direction. The absorber 40 is configured only of the first layer 1 outboard of the outside ends 42W in the widthwise direction, and includes the first layer 41 and the second layer 42, except the portion formed with the central aperture 45, inboard of the outside ends 42W. With the inside ends 41W of the first layer 41 and the outside ends 42W of the second layer 42 as boundaries, the rigidity and thickness of the absorber 40 change. In at least one embodiment, the absorber is curved at the outside ends 42W of the second layer as boundaries where the rigidity and the like change.

Also, as the topsheet 10 and the absorber backside covering sheet 30 are stuck and fixed together at the central aperture 45, the absorber can be curved without losing its shape.

(3) Changes in the shape of the absorber
Fig. 7 is a sectional view (along line X1-X'1 in Fig. 1), schematically illustrating the wearing state of the disposable diaper 1. While the disposable diaper 1 is being worn, the urinating region S3 of the absorber contacts the crotch of a wearer. Pressure is added to the absorber inwardly in the widthwise direction by the legs, etc. of a wearer. The absorber 40 curves at the central elastic member 44 and the central aperture 45, and the first side slits 46 as base points, so that the cross-sectional shape of the disposable diaper 1 along the widthwise direction W transforms into a wavy form. Thus, the urinating region 33 of the absorber 40 turns into an evenly folded-up condition.

The absorber 40 contacts the crotch portion of a wearer with its top surface projected towards the inward direction IN by the central elastic member 44. The portion projected by the central curving unit includes only the second layer 42, and is relatively thin. The first layer 41 and the second layer 42 overlap each other between the portion projected by central curving unit and the portions projected by the first curving units, and the overlapping portion is relatively thick and has a high rigidity. With the portions having a high rigidity between the central curving unit and the first curving units, the portion projected by the central curving unit can be supported, thus improving the stability of the convex shape projected by the central curving unit.

A center groove or a slit that extends in the longitudinal direction, may be provided at the center of the central curving unit. By providing the center groove or the slit extending in the longitudinal direction at the center of the central curving unit, a concave portion that is directed towards the non-skin contact surface side, may be formed at the center in the widthwise direction of the central curving unit that is projecting towards the skin contact surface side. For instance, when a slit is formed at a location opposite to the central aperture of the second layer, the absorber is not arranged at the portion formed with the slit, so that the topsheet of the portion may be deformed so as to curve towards the backsheet and thus to curve so as to project outwardly .

Moreover, when a wearer closes both legs, the absorber is folded up at the central curving unit and also at the first curving units, and is positioned closely and compactly under the crotch portion, based on the cross-sectional shape of the disposable diaper 1.

The central curving unit formed by the central elastic member 44 and the central aperture 45, is positioned so as to be in contact with the crotch portion of a wearer. On the other hand, the first curving units formed by the first side slits 46, project towards the non-skin contact surface side and do not contact a wearer's excretion portion.

The absorber is in close contact with the crotch portion of a wearer, so that body fluid is prevented from leaking even when urine is released rather slowly along the wearer's skin. Also, at the curving units of the absorber that are folded away from the skin, concavities extending in the longitudinal direction are formed, so that body fluid can be spread out in the longitudinal direction and side leakage can be prevented.

The absorber is folded up at the central aperture 45 and the first side slits 46 formed in the absorber as the base points, so that the absorber 40 can curve more easily even when swollen with liquid than the absorber 40 having a portion protruded by forming a thinner portion. The cross section of the absorbent 40, deformed by wearing the disposable diaper 1, has a tapering shape from the non-skin contact surface side towards the skin contact surface side. Thus, the diaper is likely to fit into the crack of the crotch portion of a wearer with little discomfort.

The convex portion formed by the central curving unit is configured only of the second layer 42, and is thinner than the portion of a laminated first layer 41 and second layer 42. In other words, due to a thin and high structure, the convex portion formed by the central curving unit can be easily inserted in the thin gap of the crotch portion, and easily comes in close contact with the excretion portion. Since the urethral opening is in close contact with the absorber, excreted urine can be quickly absorbed. The absorber is folded up in such a way that the absorber is thin at a portion close to the skin of a wearer's crotch portion and is thick at a portion away from the skin, thus providing a comfortable fit.

Since the portion is likely to get into a narrow crack at the crotch portion of a body, the central aperture 45 is positioned closer to a urinating portion. By narrowing a distance between the central aperture 45 and the urinating portion, excreted urine can be spread in the longitudinal direction by the central aperture 45 and can be guided to the absorbent sheet 90 at the back waistline region S2. By smoothly guiding body fluid to the absorbent sheet 90, the fluid is localized to a portion with high absorbent capacity, so that absorption properties can be further increased by using the absorption capability more effectively.

As a method of manufacturing the absorbent article configured thereby, the absorbent article can be manufactured by a method including the steps of, for instance, forming a first layer of an absorber, forming a second layer of the absorber, combining the first layer and the second layer, transporting the absorber, etc. by a belt conveyor or the like, and joining sheet materials such as an absorbent sheet and a topsheet during the transporting process. For other steps, various manufacturing methods may be applied.

When an aperture and side slits are provided at both first layer and second layer, there may be a problem in aligning the layers together in case of laminating the first and the second layers. For instance, when the layers are not aligned in the widthwise direction, the width of a pair of the left and right side slits become narrow and the absorber might not be evenly deformed or may have an unbalanced shape between the right and left sides, which may cause negative effects on absorbency and fit. However, by providing an aperture or side slits to at least one of the first layer and the second layer, the side slits or the like are prevented from being dislocated from each other.

(Disposable Diaper of First Modification)
Subsequently, the configurations of absorbers of disposable diapers relating to various modifications will be explained by referring to the figures. For the same configuration as in the above-mentioned embodiments, the same reference numerals are used and the explanation thereof is omitted.

Fig. 8(a) and Fig. 8(b) show the absorber relating to a first modification. Fig. 8(a) is a plan view, and Fig. 8(b) is a sectional view along the longitudinal direction at the center of the absorber in the widthwise direction.

An absorber 40G relating to the first modification is configured of one layer having a roughly hourglass shape. The absorber 40G has a first region R1 having absorbent polymer, and a second region R2 in which absorbent polymer has a lower basis weight than the absorbent polymer in the first region R1. The first region is illustrated with oblique lines in Figs. 8A and 8B. The region surrounding the first region at the absorber is the second region. The first region is configured by providing the absorbent polymer intermittently, and is provided at the non-skin contact surface side of the back waistline region S2 that is adapted to be in contact with a buttock. For example, the first region R1 is defined by an absorbent sheet, such as the absorbent sheet 90, disposed on the non-skin contact surface side of the back waistline region S2.
Additionally, as long as the second region has a lower basis weight than the absorbent polymer of the first region, the second region may not have the absorption polymer (the basis weight of the absorbent polymer is 0 g/m²).

Fig. 8(c) and Fig. 8(d) show an absorber 40H relating to a second modification. Fig. 8(c) is a plan view, and Fig. 8(d) is a sectional view along the longitudinal direction at the center of the absorber in the widthwise direction.

The absorber 40H relating to the second modification is configured of one layer having a roughly hourglass shape. The first region R1 is configured by arranging a highly absorbent core that is a high basis weight region in which absorbent polymer has a higher basis weight than the second region R2 surrounding the first region. The first region R1 is arranged at the non-skin contact surface side of the back waistline region S2 that is adapted to be in contact with the buttock portion. For example, the first region R1 is defined by an absorbent sheet, such as the absorbent sheet 90, disposed on the skin contact surface side of the back waistline region S2.

The back end of the central aperture of the absorber overlaps the first region in the thickness direction. By overlapping the body fluid guiding unit with the first region like this, the body fluid absorbed at the urinating region S3 can be directly guided to the first region. Accordingly, body fluid is swiftly and precisely shifted to the first region, thus improving the utilization ratio of the absorbent polymer arranged at the first region.

Since the first region is arranged at the skin contact surface side at the central aperture of the absorber, the body fluid guided through the central aperture is absorbed from the non-skin contact side of the first region. Therefore, body fluid is unlikely to stick to skin with little wet feeling.

Fig. 8(e) and Fig. 8(f) show an absorber 40J relating to a third modification. Fig. 8(e) is a plan view, and Fig. 8(f) is a sectional view along the longitudinal direction at the center of the absorber in the widthwise direction.

The absorber 40J of the third modification includes one layer in a roughly hourglass shape. The first region R1 is formed of a portion of the absorber in which absorbent polymer has a higher basis weight, and is arranged at the back waistline region S2 that is adapted to be in contact with the buttock portion.
In the configuration where, as in the third modification, the first region is integrated with the absorber, the weight ratio of the absorbent polymer can be measured by, for example, the following method.
The absorber is divided into the absorber of the skin contact surface side and the absorber of the non-skin contact surface side in the thickness direction. With respect to the absorber of the skin contact surface side, a sieve or the like is used to separate the polymer and the pulp fibers, and the weights of each of the polymer weight C (g) and the pulp fiber weight D (g) are measured. Any of various means can be used for the means for separating, provided that both can be substantially entirely separated. For example, by utilizing a difference in particle size, a fine mesh may be used for the sieve separation, or the difference in weight may be used, where the sample is placed under an air flow such that only the pulp is scattered and the weight before and after scattering is measured.
The calculation can be performed such that the absorbent polymer weight ratio (%) = polymer weight (C)/ (polymer weight (C) plus pulp fiber weight (D)) times 100.
Additionally, the absorber shown in Figs. 8 (e) and 8 (f) can be manufactured by, for instance, the following methods. In the first manufacturing method, after an absorbent material constituting the second region R2 is deposited, an absorbent material constituting the first region R1 and SAP are deposited on the absorbent material constituting the second region R2. Then, the whole surface of the laminated absorbent materials is pressed in a thickness direction to thereby form the absorber with a uniform thickness. Further, in the second manufacturing method, absorbent material is deposited, and a thickness of the absorbent material as a part defined as the first region S1 is made thinner than that of the absorbent material within its surrounding region (the second region). Yet further, SAP is mixed in the absorbent material as a part defined as the first region R1. Subsequently, the whole surface of the laminated absorbent material is pressed in the thickness direction to thereby form the absorber with a uniform thickness. With such a structure, the absorber shown in Figs. 8 (e) and 8 (f) can be manufactured.

Fig. 8(g) and Fig. 8(h) show the absorber 40K relating to a fourth modification. Fig. 8(g) is a plan view, and Fig. 8(h) is a sectional view along the longitudinal direction at the center of the absorber in the widthwise direction.

The absorber 40K relating to the fourth modification includes one layer in a roughly hourglass shape. The first region R1 is configured by providing the absorbent polymer intermittently. For example, the first region R1 is defined by an absorbent sheet, such as the absorbent sheet 90, disposed on the skin contact surface side of the back waistline region S2. In the absorber, a low basis weight region 47 which functions as the body fluid guiding unit and the curving unit, is formed along the longitudinal direction.

Fig. 9 is a plan view of a disposable diaper relating to a further modification. In the disposable diaper, the inside end of the leg hole elastic member in the widthwise direction extends to the center of the absorber in the widthwise direction, and the left and right leg hole elastic members are continuous. These continuous elastic members function as widthwise elastic members which are elastic in the widthwise direction and extend across the absorber.

Since the leg hole elastic members for left legs and right legs are arranged continuously, the leg hole elastic member can be continuously lifted up, thus allowing the back waistline region to lift up efficiently.

In such a configuration, it is normally seen that the absorber is wrinkled by the shrinkage of the leg hole elastic members, thus deteriorating absorption performance. However, in at least one embodiment, since rigidity is added by the first region overlapping the widthwise elastic members, the absorber is unlikely to form wrinkles. The first region has a large amount of absorbent polymer, so that the rigidity further increases after liquid absorption. Thus, the absorber is less likely to form wrinkles, preventing absorption performance from deteriorating.

(Other Embodiments]
As mentioned above, although several embodiments of the present invention have been disclosed, the descriptions and drawings that form a part of this disclosure are not to be considered as limitation to the present invention. From this disclosure, a variety of alternate embodiments, examples, and applicable techniques will become apparent to one ordinarily skilled in the art.

For example, in the above embodiments, a pants-type disposable diaper was explained, however, the present invention is not limited thereto, and can be applied to an open-type disposable diaper, incontinence pad, sanitary napkin, and other types of absorptive products.

In the aforementioned embodiments, the absorber was configured to be curved by using slits, elastic members, and/or boundary portions where the rigidity changes, however, the absorber can also be configured to be curved by reducing the thickness of the absorber and by performing embossing in the absorber.

Although the absorbent article of the described embodiments has the side end elastic members 49, the article may not include the side end elastic members 49 in further embodiments. Additionally, the leakage-preventing walls have uprising portions (leakage-preventing elastic members 53) so as to prohibit side leakage from a crotch portion may be omitted in some embodiments.

The absorber 40 of the described embodiments has a two-layer structure including the first layer 41 and the second layer 42, but the absorber 40 of the worn article in further embodiments of the invention may be configured of only one layer, or three or more layers.

Although the central curving unit and the first curving units are provided in the described embodiments, a plurality of curving units, such as the second curving unit and the third curving unit, may be provided outboard of the first curving units in the widthwise direction in some embodiments.

In the third modification, as an example, the first region R1 is formed by providing an absorbent polymer having a higher basis weight at a portion of a single-layer absorber. However, in some embodiments, absorbent polymer may be arranged on the top at the center in the widthwise direction of the absorber; absorbent polymer may be arranged nearly over the entire absorber in the widthwise direction; or absorbent polymer may be scattered on the surface of an absorber.

As described above, needless to say, the present invention includes various embodiments and the like not described here. Therefore, the scope of the present invention is defined only by the appended claims in view of the foregoing description.

The entire contents of Japanese Patent Application No. 2011-195206 (filed on September 7, 2011) are incorporated in the present specification by reference.

According to the characteristic provided by some embodiments of the present invention, it is possible to provide a disposable wearing article, in which the body fluid guiding units extending from the urinating region to the buttock region are formed so that the body fluid absorbed at the urinating region may be guided smoothly to an absorbent sheet at the buttock region. As body fluid is guided from the urinating region to the buttock region, the absorbed body fluid can be held not only at the absorber at the urinating region but also at the absorbent sheet arranged at the buttock region. By maintaining an absorption area, absorption properties can be kept. Thus, by effectively utilizing absorbent capacity, the absorption capability of the absorbent article as a whole will improve.

Moreover, when discharged urine is held mostly at the crotch portion, the absorber bulges out at the crotch portion, so that a wearer would have a hard time closing their legs, i.e., a major discomfort making walking difficult. However, by guiding urine away from the urinating region towards the absorbent sheet and holding the urine mostly there, absorption efficiency can improve and leakage can be reduced while decreasing the discomfort caused by a thickened absorber due to an expansion of the absorbent polymer after the absorption of urine at the crotch portion.
The buttock region has the buttock elastic members extensible and contractible at least in the longitudinal direction, so that the buttock elastic members can lift up the waistline or buttock region even when the absorbent polymer absorbs body fluid and the buttock region becomes heavy.

1: Disposable diaper (Disposable wearing article); 3: Waist gathers; 3A: Waist elastic member; 4, 4': Front waistline side edge; 5: Leg gathers; 5F: Front leg hole elastic member; 5R: Back leg hole elastic member; 6, 6': Back waistline edge; 8: middle inside leg edge; 10: Topsheet; 15: Auxiliary sheet; 30: Absorber backside covering sheet; 40, 40G, 40H, 40J, 40K: Absorber; 41: First layer; 41W: Inside end; 42: Second Layer; 42W: Outside end; 43: Elastic member covering sheet; 44: Central elastic member; 45: Central aperture; 46: First side slit; 47: Low base weight region; 49: Side end elastic member; 53: Leakage-preventing elastic member; 60: Sidesheet; 70F: Foreside exterior topsheet; 70R: Backside exterior topsheet; 80F: Foreside exterior backsheet; 80R: Backside exterior backsheet; 90: Absorbent sheet; 92, 93: Liquid-permeable sheet; 96: Absorbent polymer arranging region; 97: Absorbent polymer non-containing Region; 100: Exterior center sheet; 110: Intermediate region; R1: First region; R2: Second region; S1: Front waistline region; S2: Back waistline region; S3: Urinating Region

Claims

A disposable wearing article, comprising:
a liquid-permeable topsheet;
a backsheet;
an absorber that is provided between the topsheet and the backsheet and has a longitudinal direction and a widthwise direction which is orthogonal to the longitudinal direction;
a urinating region that is adapted to be in contact with a wearer's urinating portion, and a buttock region that is positioned behind the urinating region and is adapted to be in contact with buttocks of the wearer; and
an absorbent sheet which includes absorbent polymer sandwiched between liquid-permeable layers, and is positioned between the topsheet and the backsheet, wherein:
the absorbent sheet is arranged at the buttock region but not at the urinating region;
the absorber is positioned at least at the urinating region and has a body fluid guiding unit which extends from the urinating region towards the buttock region; and
the buttock region has buttock elastic members that are extensible and contractible at least in the longitudinal direction.
A disposable wearing article, comprising:
a liquid-permeable topsheet;
a backsheet;
an absorber that is provided between the topsheet and the backsheet and has a longitudinal direction and a widthwise direction which is orthogonal to the longitudinal direction;
a urinating region that is adapted to be in contact with a wearer's urinating portion, and a buttock region that is positioned behind the urinating region and is adapted to be in contact with buttocks of the wearer, wherein:
the absorber has a first region including absorbent polymer and a second region in which absorbent polymer has a lower basis weight than a basis weight in the first region;
the first region is arranged at the buttock region of the absorber;
the second region is arranged at the urinating region of the absorber;
the absorber has a body fluid guiding unit which extends from the urinating region towards the buttock region; and
the buttock region has buttock elastic members that are extensible and contractible at least in the longitudinal direction.
The disposable wearing article according to claim 1 or 2, wherein the body fluid guiding unit comprises at least one selected from the group consisting of:
slits that are formed at the absorber;
a compressed region; and
a low basis weight region which has a lower basis weight than a surrounding region, and is formed at the absorber.
The disposable wearing article according to any one of claims 1 to 3, wherein the buttock elastic members include a pair of leg hole elastic members that are arranged along leg holes of the article.
The disposable wearing article according to claim 4, wherein the pair of leg hole elastic members are widthwise elastic members that extend across the absorber and are extensible and contractible in the widthwise direction.
The disposable wearing article according to any one of claims 1 to 5, wherein the buttock region has waistline elastic members that are adapted to be arranged along a waistline of the wearer, and are extensible and contractible in the widthwise direction.
The disposable wearing article according to any one of claims 1 to 6, wherein
the buttock region has a plurality of polymer containing regions which the absorbent polymer is arranged, and a polymer non-containing region in which the absorbent polymer is not arranged; and
the polymer non-containing region is positioned between the adjacent polymer containing regions.
The disposable wearing article according to claim 1, wherein the absorber is further positioned at the buttock region.
The disposable wearing article according to any one of claims 1 to 8, wherein the buttock elastic members are further extensible and contractible in the widthwise direction.
The disposable wearing article according to any one of claims 7 to 9, wherein the polymer containing regions define a V-shape where the apex is directed rearwardly in the longitudinal direction.
The disposable wearing article according to any one of claims 1 to 10, wherein the absorbent sheet or the first region is arranged at a non-skin-contact side of the absorber.
The disposable wearing article according to any one of claims 1 to 11, wherein the absorbent sheet or the first region overlaps the body fluid guiding unit.
The disposable wearing article according to claim 5, wherein the absorbent sheet or the first region overlaps the widthwise elastic members.