CN114206290A

CN114206290A - absorbent articles

Info

Publication number: CN114206290A
Application number: CN202080056407.XA
Authority: CN
Inventors: 高木祐里香; 松冈宏树; 山下有一
Original assignee: Daio Paper Corp
Current assignee: Daio Paper Corp
Priority date: 2019-09-27
Filing date: 2020-09-17
Publication date: 2022-03-18
Anticipated expiration: 2040-09-17
Also published as: WO2021060134A1; JP2021052901A; TWI864111B; CN114206290B; TW202112331A; JP7291053B2

Abstract

Absorbency for viscous liquids can be improved. The above problem is solved by the following absorbent article, characterized in that the absorbent article includes: an absorber (70); and a liquid-permeable topsheet (30) disposed on the front side of the absorber (70), The absorber (70) includes a chamber absorbent sheet (50) having a liquid-permeable upper sheet (51) and a lower sheet (52), and a chamber (55) which is a top sheet ( 51 ) and the joint portion ( 54 ) of the lower sheet ( 52 ) are surrounded around the portion where the upper sheet ( 51 ) and the lower sheet ( 52 ) are not joined together; and contain superabsorbent polymer particles ( 53 ) The powder and granular body is accommodated in the chamber (55), and the upper sheet (51) is a superabsorbent non-woven fabric with a Kremlin water absorption of 50 mm or more.

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article having improved absorption performance.

Background

The absorbent article is provided with: an absorbent body; a liquid-permeable top sheet covering the front surface side of the absorbent body; and a liquid-impermeable sheet covering the back surface side of the absorbent body, and excretory fluid such as urine or menstrual blood is absorbed and retained by the absorbent body through the top sheet. As the absorbent body, an absorbent body in which super absorbent polymer particles (SAP) are mixed with hydrophilic short fibers such as pulp fluff and are stacked in a cotton shape is widely used, but in order to satisfy requirements such as further thinning, weight reduction, and cost reduction while securing a sufficient absorbable amount, various absorbent sheets (hereinafter, also referred to as chamber absorbent sheets) having: a plurality of chambers (cells) surrounded by a joint portion of an upper sheet and a lower sheet having liquid permeability and formed without joining the upper sheet and the lower sheet; and a particulate material containing superabsorbent polymer particles, which is contained in the chamber (see, for example, patent documents 1 to 6 below).

However, the chamber absorbent sheet is suitable for absorbing a large amount of a non-viscous liquid such as urine as an absorption amount because absorption performance depends on the superabsorbent polymer particles, but absorption speed is slow. Therefore, when the absorption object is a viscous liquid such as muddy feces, watery feces, or a liquid component in soft stool, there are the following problems: the viscous liquid remains on the surface of the diaper for a long period of time and moves on the surface of the absorbent article, and is liable to leak from the surroundings.

Documents of the prior art

Patent document

Patent document 1: japanese Kohyo publication Hei 09-504207

Patent document 2: japanese Kokai publication Hei-2014-500736

Patent document 3: japanese patent laid-open publication No. 2011-189067

Patent document 4: japanese laid-open patent publication No. 10-137291

Patent document 5: japanese patent laid-open publication No. 2017-176507

Patent document 6: japanese laid-open patent publication No. 2010-522595

Disclosure of Invention

Problems to be solved by the invention

Therefore, a main object of the present invention is to improve the absorbability for viscous liquids.

Means for solving the problems

The absorbent article solving the above problems is as follows.

< mode 1 >)

An absorbent article characterized in that,

the absorbent article is provided with: an absorbent body; and a liquid-permeable top sheet disposed on the front surface side of the absorbent body,

the absorbent body includes a cavity absorbent sheet having: an upper sheet and a lower sheet having liquid permeability; a chamber which is a portion surrounded by the joining portion of the upper sheet and the lower sheet and in which the upper sheet and the lower sheet are not joined together; and a powder or granule containing superabsorbent polymer particles, which is contained in the chamber,

the upper sheet is a high water absorption non-woven fabric with the gram water absorption degree of more than 100 mm.

(Effect)

Although it is important to improve the permeability of viscous liquid in the layer covering the front side of the absorbent body, the rapid permeability of viscous liquid is promoted by the rapid intake of the absorbent body. That is, the initial absorption rate of the uppermost portion of the absorbent body is extremely important for the absorption of viscous liquid. The present absorbent article is based on such an insight. The absorbent article is characterized in that a material specially used for absorbing viscous liquid is used for the upper sheet of the chamber absorber. That is, the top sheet is a high water-absorbent nonwoven fabric having a Klebs water absorption degree of 100mm or more, and can rapidly absorb and diffuse even a viscous liquid. Therefore, the absorbability of the viscous liquid can be remarkably improved. In addition, the viscous liquid absorbed and diffused by the top sheet can be transferred to the super absorbent polymer particles in the chamber absorbent sheet and absorbed and held by the super absorbent polymer particles.

< 2 nd mode >)

The absorbent article according to claim 1, wherein the super absorbent nonwoven fabric constituting the top sheet contains 50% or more of pulp fibers or rayon fibers and has a basis weight of 25g/m²～50g/m²The wet nonwoven fabric of (1).

(Effect)

The use of such a wet nonwoven fabric is preferable because the non-viscous liquid can be rapidly absorbed and diffused by capillary action due to the minute fiber gaps. In addition, since such a wet nonwoven fabric has a high klemm water absorption degree and is very thin and flexible, it is possible to suppress a decrease in flexibility and an increase in thickness of the entire chamber absorbent sheet.

< mode 3 >)

The absorbent article according to claim 2, wherein the wet nonwoven fabric has: a support layer comprising long fibers of a synthetic resin; and a pulp layer composed only of pulp fibers, which is located at a position most on the front surface side.

(Effect)

Such a wet nonwoven fabric is preferable because the water retention property on the upper side of the upper sheet can be improved by the pulp layer and the strength can be improved by the presence of the support layer.

< 4 th mode >)

The absorbent article according to any one of aspects 1 to 3, wherein the chamber absorbent sheet contains superabsorbent polymer particles adjacent to the back surface of the top sheet.

(Effect)

It is preferable that the chamber absorption sheet has superabsorbent polymer particles adjacent to the back surface of the top sheet, since the viscous liquid absorbed and diffused by the top sheet can be efficiently transferred to the superabsorbent polymer particles.

< 5 th mode >)

The absorbent article according to any one of aspects 1 to 4, wherein a portion of the upper sheet located in each chamber is pushed out upward, and a pair of concave and convex portions is formed on an upper surface and a lower surface of the upper sheet.

(Effect)

In the chamber absorbent sheet, in order to ensure the volume when the superabsorbent polymer particles inside absorb and expand, it is preferable that at least one of the upper sheet and the lower sheet has a concave portion in which a portion located in each chamber is extruded outward in the thickness direction. Here, if the upper sheet has the concave portion, the surface area of the upper sheet is increased, and the liquid can be supplied to the super absorbent polymer particles in the chamber absorbent sheet in a wider range, which is preferable.

< mode 6 >)

The absorbent article according to any one of aspects 1 to 5, wherein the absorbent article includes a liquid-impermeable sheet disposed on a back side of the absorber,

the lower sheet is a high-water-absorption nonwoven fabric having a Klelm water absorption of 50mm or more, a water retention under load of 0.1g or more, and a water retention under no load of 0.5g or more.

(Effect)

As described above, since the absorption speed of the chamber absorbent sheet is slow, the non-viscous liquid that has passed through the chamber absorbent sheet moves on the liquid impermeable sheet, and seeps out from the periphery of the chamber absorbent sheet toward the skin side, and may adhere to the skin or leak. In contrast, in the present absorbent article, the non-viscous liquid that has reached the lower sheet without being absorbed by the superabsorbent polymer particles, among the non-viscous liquid supplied to the chamber absorbent sheet, is absorbed by the lower sheet, retained and diffused in the lower sheet, and then can be sucked up by the superabsorbent polymer particles in the chamber absorbent sheet. Therefore, the following concerns can be reduced: the non-viscous liquid that has passed through the chamber absorbent sheet moves on the liquid-impermeable sheet, and seeps out from the periphery of the chamber absorbent sheet toward the skin side to adhere to the skin or leak. As a result, the liquid absorbent composition can simultaneously achieve both the absorbency for viscous liquids and the absorbency for non-viscous liquids.

< 7 th mode >)

The absorbent article according to claim 6, wherein the portions of the lower sheet located in the chambers are pushed out downward, and a pair of concave portions and convex portions are formed on the upper surface and the lower surface of the lower sheet.

(Effect)

If the lower sheet has a recess, the surface area of the lower sheet becomes large, and the water holding amount of the lower sheet is preferably larger than that in the case where the lower sheet is flattened without being subjected to shaping.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention has the following advantages: the absorbability to the viscous liquid can be improved.

Drawings

Fig. 1 is a plan view showing the inner surface of a tape-type disposable diaper in a state where the diaper is unfolded.

Fig. 2 is a plan view showing the outer surface of the tape-type disposable diaper in a state where the diaper is unfolded.

Fig. 3 is a cross-sectional view taken along line 6-6 of fig. 1.

Fig. 4 is a cross-sectional view taken along line 7-7 of fig. 1.

Fig. 5 (a) is a sectional view taken along line 8-8 of fig. 1, and (b) is a sectional view taken along line 9-9 of fig. 1.

Fig. 6 is a cross-sectional view taken along line 5-5 of fig. 1.

Fig. 7 (a) is a sectional bottom view of an important part of the absorbent body, and (b) is a sectional view thereof taken along the line 1-1.

Fig. 8 is a plan view of the absorber.

Fig. 9 is a plan view of the absorber.

Fig. 10 is a cross-sectional view taken along line 2-2 in fig. 8 and 9.

Fig. 11 is a plan view schematically showing the absorber of the joint portion.

Fig. 12 is a schematic plan view showing various arrangement examples of the chamber.

Fig. 13 is a sectional view of various chamber absorbent sheets.

Fig. 14 is a sectional view of various chamber absorbent sheets.

Fig. 15 is a sectional view showing the layer structure of the absorber and the wrapping sheet.

Fig. 16 is a cross-sectional view showing a change in absorption.

Fig. 17 is a sectional view schematically showing the layer structure of the super absorbent nonwoven fabric.

Detailed Description

Hereinafter, a tape type disposable diaper will be described as an example of the absorbent article with reference to the drawings. Fig. 1 to 6 show an example of a tape-type disposable diaper, in which the reference numeral X denotes the full width of the diaper except for the fastening tape, and the reference numeral L denotes the entire length of the diaper. The respective components adjacent in the thickness direction are fixed or joined as necessary in the same manner as in a known diaper except for the fixing or joining portions described below. The dotted portions in the cross-sectional view indicate adhesives such as hot melt adhesives as the fixing or joining means. The hot melt adhesive can be applied by a known method such as slit coating, continuous linear or dotted droplet coating, spiral, zigzag, wavy spray coating, or pattern coating (transfer of hot melt adhesive in relief). Instead of these methods or together with these methods, a hot-melt adhesive can be applied to the outer circumferential surface of the elastic member at the fixing portion of the elastic member to fix the elastic member to an adjacent member. Examples of the hot melt adhesive include EVA adhesives, adhesive rubber adhesives (elastic adhesives), olefin adhesives, and polyester polyamide adhesives, and can be used without particular limitation. As a fixing or joining means for joining the respective constituent members together, a material-based welding means such as heat sealing or ultrasonic sealing may be employed. In a portion where liquid permeability in the thickness direction is required, constituent members adjacent in the thickness direction are fixed or joined in a discontinuous pattern. For example, when such intermittent fixing or bonding is performed by a hot-melt adhesive, it is possible to appropriately apply intermittent pattern coating such as spiral, Z-shaped, wave-shaped, or the like, and when the coating is applied to a range of a coating width by one nozzle or more, it is possible to apply intermittent pattern coating such as spiral, Z-shaped, wave-shaped, or the like with or without an interval in the width direction.

The tape-type disposable diaper has a basic structure of: the absorbent body 70 is interposed between the top sheet having liquid permeability and the liquid-impermeable sheet on the back side. The tape-type disposable diaper has end flaps EF which are portions extending to the front side and the rear side of the absorbent body 70, respectively, and which are portions not having the absorbent body 70, and a pair of side flaps SF extending to the side than the side edges of the absorbent body 70. The side flaps SF have a shape that narrows so as to extend along the leg circumferences, but may have a straight shape. The side flaps SF in the back-side portion B are provided with fastening tapes 13, respectively, and the fastening tapes 13 are locked to appropriate portions of the outer surface of the abdomen-side portion F in a state where the side flaps SF of the back-side portion B are superposed on the outer sides of the side flaps SF of the abdomen-side portion F when the diaper is worn.

In this tape-type disposable diaper, the entire outer surface except the fastening tape 13 is formed of the outer-cover nonwoven fabric 12. In particular, in the region including the absorbent body 70, the liquid-impermeable sheet 11 is fixed to the inner surface side of the outer-covering nonwoven fabric 12 with an adhesive such as a hot-melt adhesive, and the absorbent body 70, the intermediate sheet 40, and the top sheet 30 are laminated in this order on the inner surface side of the liquid-impermeable sheet 11. The top sheet 30 and the liquid-impermeable sheet 11 are rectangular in the illustrated example and have a dimension slightly larger than the absorbent body 70 in the front-back direction LD and the width direction WD, and the peripheral edge portion of the top sheet 30 that extends beyond the side edge of the absorbent body 70 and the peripheral edge portion of the liquid-impermeable sheet 11 that extends beyond the side edge of the absorbent body 70 are joined together by a hot-melt adhesive or the like. In addition, the liquid-impermeable sheet 11 is formed to be slightly wider than the top sheet 30.

Further, standing gather portions 60 standing up toward the skin of the wearer are provided on both sides of the tape-type disposable diaper, and gather sheets 62 forming the standing gather portions 60 are fixed in the range from the both side portions of the top sheet 30 to the inner surface of each side flap SF.

The details of each part will be described in turn below. As the nonwoven fabric in the following description, a known nonwoven fabric can be used as appropriate depending on the location and the purpose. As the constituent fibers of the nonwoven fabric, for example, synthetic fibers such as olefin-based fibers (e.g., polyethylene, polypropylene, etc.), polyester-based fibers, polyamide-based fibers (composite fibers having a structure such as a core-sheath in addition to single-component fibers), regenerated fibers such as rayon, cuprammonium fiber, etc., natural fibers such as cotton, etc., can be used without particular limitation, and these fibers may be mixed together. In order to improve the flexibility of the nonwoven fabric, the constituent fibers are preferably crimped fibers. The constituent fibers of the nonwoven fabric may be hydrophilic fibers (including fibers having hydrophilicity with a hydrophilic agent), or hydrophobic fibers or water-repellent fibers (including fibers having water repellency with a water-repellent agent). The nonwoven fabric is generally classified into a short fiber nonwoven fabric, a long fiber nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, a hot-rolled (hot-air) nonwoven fabric, a needle-punched nonwoven fabric, a point-bonded nonwoven fabric, a laminated nonwoven fabric (an SMS nonwoven fabric, an SMMS nonwoven fabric, or the like in which a meltblown layer is sandwiched between spunbond layers) and the like according to the length of the fiber, the sheet forming method, the fiber bonding method, and the laminated structure, and any of these nonwoven fabrics can be used.

(nonwoven fabric for exterior application)

The outer nonwoven fabric 12 constitutes the outer surface of the product and serves to give the outer surface a cloth-like appearance and a skin touch. The weight of the fiber unit area of the exterior nonwoven fabric is preferably 10 to 50g/m²Particularly preferably 15 to 30g/m². The outer-covering nonwoven fabric 12 may be omitted, and in this case, the liquid-impermeable sheet 11 may be formed in the same shape as the outer-covering nonwoven fabric 12 to form the outer surface of the product.

(liquid-impermeable sheet)

The material of the liquid-impermeable sheet 11 is not particularly limited, and examples thereof include olefin resins such as polyethylene and polypropylene, laminated nonwoven fabrics obtained by laminating nonwoven fabrics on polyethylene sheets, and nonwoven fabrics having substantially secured liquid-impermeability with a waterproof film interposed therebetween (in this case, the liquid-impermeable sheet is composed of a waterproof film and a nonwoven fabric). Of course, in addition to these, a material having liquid impermeability and moisture permeability which is preferably used in recent years from the viewpoint of prevention of stuffiness and wetness can be exemplified. As the sheet of the material having liquid impermeability and moisture permeability, for example, a microporous sheet obtained by the following method can be exemplified: the inorganic filler is kneaded with an olefin resin such as polyethylene or polypropylene to form a sheet, and then the sheet is uniaxially or biaxially stretched. Further, as the liquid-impermeable sheet 11, a sheet having liquid-impermeability without using a waterproof film may be used, and such a sheet achieves liquid-impermeability by the following method: a non-woven fabric using micro fine denier fiber is used; a leak-proof reinforcing treatment for reducing the voids of the fibers by applying heat or pressure; coating high water absorption resin or hydrophobic resin or water repellent.

(Top sheet)

The top sheet 30 has a liquid-permeable property, and examples thereof include a porous or non-porous nonwoven fabric, a porous plastic sheet, and the like. Both side portions of the top sheet 30 may be folded back toward the back side of the absorbent body 70, or may extend laterally from the side edges of the absorbent body 70 without being folded back as in the illustrated example.

For the purpose of preventing positional deviation with respect to the back side member, it is desirable that the top sheet 30 is fixed to a member adjacent on the back side by a bonding means based on material fusion such as heat sealing or ultrasonic sealing, or a hot melt adhesive. In the illustrated example, the top sheet 30 is fixed to the front surface of the intermediate sheet 40 and the front surface of the portion of the packaging sheet 45 on the front surface side of the absorbent body 70 by a hot melt adhesive applied to the back surface thereof.

(intermediate sheet)

The intermediate sheet 40 is joined to the back surface of the top sheet 30 in order to quickly move the excreta liquid that has passed through the top sheet 30 toward the absorbent body 70 and to prevent backflow. The joining of the intermediate sheet 40 and the top sheet 30 may be performed by hot embossing or ultrasonic welding, in addition to using a hot-melt adhesive.

As the intermediate sheet 40, a resin film having a plurality of through holes may be used in addition to the nonwoven fabric. The nonwoven fabric may be made of the same material as the top sheet 30, but is preferably a nonwoven fabric having higher hydrophilicity than the top sheet 30 or a nonwoven fabric having higher fiber density than the top sheet 30 because the nonwoven fabric has excellent transfer characteristics for transferring liquid from the top sheet 30 to the intermediate sheet 40.For example, as the intermediate sheet 40, a hot air nonwoven fabric can be suitably used. In the air-through nonwoven fabric, a composite fiber having a core-sheath structure is preferably used, and in this case, the resin used for the core may be polypropylene (PP), but Polyester (PET) having high rigidity is preferred. The weight per unit area is preferably 17 to 80g/m²More preferably 25 to 60g/m². The thickness of the raw material fiber of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is preferable to use a bias fiber, a hollow fiber, or a bias and hollow fiber having no core at the center as a mixed fiber of all or a part of the raw material fibers.

The intermediate sheet 40 in the illustrated example is shorter than the width of the absorber 70 and is disposed at the center, and may be provided over the entire width. The dimension of the intermediate sheet 40 in the front-rear direction LD may be the same as the entire length of the diaper, may be the same as the dimension of the absorbent body 70, or may be within a short length range centered on the liquid-receiving region.

(vertical gather part)

In order to prevent lateral movement of excrement on the top sheet 30 and to prevent side leakage, it is preferable to provide standing gather portions 60 that protrude (stand) from the inner surfaces on both sides of the product in the width direction WD.

The standing gather portion 60 is constituted by: a gusset 62; and an elongated gather portion elastic member 63 fixed to the gather sheet 62 in an extended state along the front-rear direction LD. As the gather sheet 62, a water repellent nonwoven fabric can be used, and as the elastic member 63, a rubber thread or the like can be used. As shown in fig. 1 and 3, a plurality of elastic members may be provided on each side, or 1 elastic member may be provided on each side.

The inner surface of the gather sheet 62 has a fixing start end in the width direction WD on the side portion of the top sheet 30, and the portion outside in the width direction WD from the fixing start end is fixed to the side portion of the liquid-impermeable sheet 11 and the side portion of the outer-covering nonwoven fabric 12 positioned in this portion by a hot-melt adhesive or the like.

In the leg hole portions, the opposite end portions in the product front-rear direction LD inside in the width direction WD from the fastening start end of the standing gather portion 60 are fixed to the top sheet 30, but the portion between the opposite end portions is an unfixed free portion, and the free portion stands up by the contraction force of the elastic member 63. When the diaper is worn, the diaper is boat-shaped and worn on the body, and since the contraction force of the elastic member 63 acts, the standing gather portion 60 stands up by the contraction force of the elastic member 63 and is closely attached to the periphery of the leg portion. As a result, so-called side leakage from around the leg is prevented.

Unlike the illustrated example, both end portions in the front-rear direction LD in the portion inside the width direction WD of the gather sheet 62 may be fixed in a folded state having the following portions, and the portion between the both end portions may be an unfixed free portion: a proximal end portion extending inward from an outer portion in the width direction WD; and a distal end portion that is folded back toward the body side from an end edge on the center side in the width direction WD of the proximal end portion and extends outward in the width direction WD.

(Flat gather part)

As shown in fig. 1 to 3, in each side flap SF, a leg-surrounding elastic member 64 made of an elongated elastic member such as a rubber thread is fixed between the gather sheet 62 and the liquid-impermeable sheet 11 in an extended state along the front-rear direction LD outside in the width direction WD near the fixing start end in the fixing portion of the gather sheet 62, and thus the leg-surrounding portion of each side flap SF is configured as a planar gather portion. The leg hole elastic members 64 may be disposed between the liquid-impermeable sheet 11 and the outer-covering nonwoven fabric 12 in the side flaps SF. The leg hole elastic members 64 may be provided only by 1 on each side, in addition to the plurality of members provided on each side as in the illustrated example.

(fastening tape)

As shown in fig. 1, 2 and 6, the fastening tape 13 has: a sheet base material that constitutes a belt attaching portion 13C fixed to a side portion of the diaper and a belt body portion 13B protruding from the belt attaching portion 13C; and a locking portion 13A for the ventral side provided in a middle portion in the width direction WD of the belt main body portion 13B in the sheet base material, and a portion closer to the distal end side than the locking portion 13A is set as a grasping portion. The tape attaching portion 13C of the fastening tape 13 is sandwiched between the gather sheet 62 constituting the inner layer of the side flap SF and the exterior nonwoven fabric 12 constituting the outer layer, and is bonded to these sheets by a hot melt adhesive. The locking portion 13A is fixed to the sheet base material with an adhesive.

As the locking portion 13A, a hook (a projection) of a mechanical fastener (a surface fastener) is preferable. The hook has a plurality of engaging projections on an outer surface side thereof. The shape of the engaging projection may be レ -shaped, J-shaped, mushroom-shaped, T-shaped, double J-shaped (a shape in which J-shaped structures are joined back to back), or the like, but may be any shape. Of course, an adhesive layer may be provided as the locking portion of the fastening tape 13.

As a sheet base material forming a portion from the tape mounting portion 13C to the tape main body portion 13B, various nonwoven fabrics such as spun bond nonwoven fabric, hot air nonwoven fabric, and spunlace nonwoven fabric, as well as a plastic film, polyethylene laminated nonwoven fabric, paper, or a composite material thereof can be used.

(target sheet)

Preferably, a target piece 12T having a target for facilitating the locking is provided at a portion of the ventral portion F to be locked with the fastening band 13. In the target sheet 12T, when the locking portion 13A is a hook material, a target sheet in which a plurality of loop lines around which the engaging protrusions of the hook material are wound are provided on the surface of a sheet base material made of a plastic film or a nonwoven fabric may be used, and when the locking portion 13A is an adhesive material layer, a target sheet in which a peeling treatment is performed on the surface of a sheet base material made of a plastic film having a smooth surface such as a high adhesiveness may be used as the target sheet 12T. In the case where the locking portion of the stomach-side portion F to be locked with the fastening tape 13 is formed of a nonwoven fabric (for example, the exterior nonwoven fabric 12 illustrated in the figure is formed of a nonwoven fabric) and the locking portion 13A of the fastening tape 13 is a hook member, the hook member may be hung on the nonwoven fabric of the exterior nonwoven fabric 12 to be locked without the target piece 12T. In this case, the target sheet 12T may be provided between the outer nonwoven fabric 12 and the liquid-impermeable sheet 11.

(absorber)

As shown in fig. 1, 3, 5, and 15, the absorbent body 70 is a portion that absorbs and retains the liquid component of excrement. The absorber 70 can be bonded to at least one of the front and back surfaces thereof with an adhesive 50h such as a hot melt adhesive.

As shown in the drawing, the absorbent body 70 is preferably a cavity absorbent sheet 50 having: a plurality of chambers 55 (cells) surrounded by the joint portions 54 of the upper sheet 51 and the lower sheet 52 having liquid permeability and not joined together with the upper sheet 51 and the lower sheet 52; and a powder containing superabsorbent polymer particles 53 contained within the chamber 55.

The chamber absorption sheet 50 is explained in more detail. As shown in fig. 7 in an enlarged manner, the chamber absorption sheet 50 has: an upper sheet 51; a lower sheet 52 disposed on the back side thereof; a chamber (small chamber) 55 which is a portion surrounded by the joining portion 54 of the upper sheet 51 and the lower sheet 52 and in which the upper sheet 51 and the lower sheet 52 are not joined together; and superabsorbent polymer particles 53 contained within the chamber 55. The chamber 55 is arranged in plural at intervals corresponding to the amount of the engaging portion 54. In this way, by distributing and holding the superabsorbent polymer particles 53 in the plurality of chambers 55 surrounded entirely around the joined portion 54, it is possible to prevent the superabsorbent polymer particles 53 in the chamber absorbent sheet 50 from being unevenly distributed.

In order to facilitate the disposition of the super absorbent polymer particles 53 at the time of production and to secure the volume after the absorption and expansion, it is preferable that at least one of the upper sheet 51 and the lower sheet 52 in the chamber 55 is a concave portion 50c that is concave outward of the chamber 55 in the expanded state, but the super absorbent polymer particles 53 may be sandwiched only between the upper sheet 51 and the lower sheet 52 without the concave portion 50 c.

The concave portion 50c can be formed by applying shaping processing such as embossing processing to the target sheet. Further, by this embossing, convex portions 50p bulging outward are formed in the portions of the target sheet located in the respective cavities 55. That is, when the concave portions 50c are formed in the upper sheet 51 by the embossing process, the portions of the upper sheet 51 located in the respective cavities 55 are pushed out upward to form the convex portions 50p bulging upward. The depth 50d of the recess 50c is not particularly limited, but is preferably 1.0 to 7.0mm, and particularly preferably about 1.0 to 5.0 mm.

The size of the projection 50p can be determined as appropriate, but from such a viewpoint, it is preferable that the size 55L of the projection 50p of the upper sheet 51 in the front-rear direction LD is 6 to 30mm, the size 55W of the projection 50p of the upper sheet 51 in the width direction WD is 7 to 50mm, the width 54W of the joint 54 is 1.0 to 1.8mm, and the depth 50d of the valley of the upper sheet 51 (the height of the projection 50 p) is 1.0 to 7.0 mm.

On the other hand, as shown in fig. 7 (b), fig. 13 (a), and the like, an intermediate sheet 80 made of nonwoven fabric is preferably interposed between the upper sheet 51 and the lower sheet 52, but as shown in fig. 14 (b), the intermediate sheet 80 may not be provided. In the case where the intermediate sheet 80 is provided, three layers of the upper sheet 51, the intermediate sheet 80, and the lower sheet 52 are joined at the joining portion 54. In addition, it is preferable that the intermediate sheet 80 is compressed in the thickness direction at the portion located at the joint 54, and expands into the recess 50c at the portion located in the cavity 55 (in other words, the fiber density decreases the further away from the joint). Thus, the concave portions 50c (and therefore also the convex portions) are less likely to be crushed by the pressure applied in the packaged state of the product or the pressure applied when worn, and even if crushed, the shape can be restored to at least the portion into which the intermediate sheet 80 enters or the volume close thereto by the elasticity of the intermediate sheet 80. Further, when the excretory fluid is absorbed, the superabsorbent polymer can expand the fiber space of the intermediate sheet 80 and enter therebetween, or easily compress the intermediate sheet 80, or swell through both, so the presence of the intermediate sheet 80 hardly hinders the superabsorbent polymer particles 53 from swelling. Further, since the fibers of the intermediate sheet 80 spreading into the concave portions 50c ensure a liquid passage toward each superabsorbent polymer particle 53, even after the superabsorbent polymer particles 53 start to swell, a decrease in diffusibility is suppressed, and gel blocking is less likely to occur. Therefore, the absorption rate (particularly at the initial stage of absorption) of the disposable diaper including the present chamber absorbent sheet 50 is improved by the synergistic effect of these factors.

(Upper piece)

The top sheet 51 is preferably a high water-absorbent nonwoven fabric having a Klelm water absorption of 100mm or more. By providing such an upper sheet 51, as shown by an arrow in fig. 16 (a), even a viscous liquid N can be rapidly absorbed and diffused, transferred to the super absorbent polymer particles 53, and absorbed and held by the super absorbent polymer particles 53. Therefore, the absorption of viscous liquid by the absorbent body 70 can be significantly improved. In particular, if the chamber absorbent sheet 50 has the super absorbent polymer particles 53 adjacent to the back surface of the top sheet 51, the viscous liquid N absorbed and diffused by the top sheet 51 can be efficiently transferred to the super absorbent polymer particles, which is preferable.

It is particularly preferable that the superabsorbent nonwoven fabric constituting the top sheet 51 has a klem water absorption of 130mm or more. The upper limit of the klemm water absorbency of the super absorbent nonwoven fabric constituting the top sheet 51 is not particularly limited, but is preferably about 180mm, and particularly preferably 160 mm.

The water retention capacity under load of the superabsorbent nonwoven fabric 42 of the top sheet 51 is preferably more than 0g and not more than 0.15g, and particularly preferably more than 0g and not more than 0.12 g. The water retention capacity under no load of the superabsorbent nonwoven fabric 42 of the top sheet 51 is preferably more than 0g and not more than 0.7g, and particularly preferably more than 0g and not more than 0.3 g.

The high water-absorbent nonwoven fabric constituting the top sheet 51 is not limited by the material and the production method, but is preferably one containing 50% or more pulp fibers or rayon fibers and having a basis weight of 25 to 50g/m²The wet nonwoven fabric (particularly, wet spunlace nonwoven fabric) of (1). For fibers other than pulp fibers and rayon fibers, synthetic fibers (including composite fibers such as core-sheath fibers in addition to single-component fibers) such as olefin-based fibers, polyester-based fibers, and polyamide-based fibers, such as polyethylene and polypropylene, can be used. The use of such a wet nonwoven fabric is preferable because the viscous liquid can be rapidly absorbed and diffused by capillary action due to the minute fiber gaps. In particular, since such a wet nonwoven fabric has a high klemm water absorption degree and is very thin and flexible, it is possible to suppress a decrease in flexibility and an increase in thickness of the entire chamber absorbent sheet 50. The thickness of the super absorbent nonwoven fabric constituting the top sheet 51 is not limited, but is preferably about 0.13 to 0.48mm in the case of the above-mentioned basis weight.

As the super absorbent nonwoven fabric constituting the upper sheet 51, as shown in fig. 17, a two-layer or three-layer or more super absorbent nonwoven fabric 42 having a support layer 42b containing long fibers of synthetic resin and a pulp layer 42a composed only of pulp fibers on the front surface side is particularly suitable. Such a super absorbent nonwoven fabric 42 is preferable because the pulp layer 42a can increase the klemm water absorption and the support layer 42b can increase the strength.

If the upper sheet 51 has the concave portions 50c, the surface area of the upper sheet 51 is increased, and the liquid can be supplied to the superabsorbent polymer particles in the chamber absorbent sheet 50 in a wider range, which is preferable.

The material of the lower sheet 52 is not particularly limited, but is preferably a high water-absorbent nonwoven fabric having a Klebs water absorption of 50mm or more, a water retention under load of 0.1g or more, and a water retention under no load of 0.5g or more. As shown by the arrows in fig. 16 (b), the non-viscous liquid U such as urine supplied to the chamber absorbent sheet 50 is absorbed by the superabsorbent polymer particles 53 in the chamber absorbent sheet 50, and the non-viscous liquid U reaching the lower sheet 52 without being absorbed by the superabsorbent polymer particles 53 is absorbed by the lower sheet 52, and after being retained and diffused in the lower sheet 52, can be sucked up by the superabsorbent polymer particles 53 in the chamber absorbent sheet 50. The joining portion 54 of the chamber absorbent sheet 50, which does not have the superabsorbent polymer particles 53, continuously extends toward the periphery of the chamber absorbent sheet 50, and when the projection 50p is present on the back surface of the chamber absorbent sheet 50, the gap between the back surface and the opposing surface of the chamber absorbent sheet 50 also continuously extends toward the periphery of the chamber absorbent sheet 50. Therefore, if the water retentivity of the chamber absorbent sheet 50 is low, the non-viscous liquid U that has passed through the chamber absorbent sheet 50 moves on the liquid-impermeable sheet 11 and seeps out from the periphery of the absorbent body 70 to the skin side, and may adhere to the skin or leak.

It is particularly preferable that the superabsorbent nonwoven fabric constituting the lower sheet 52 has a klem water absorption of 70mm or more. The upper limit of the klemm water absorbency of the high water absorbent nonwoven fabric constituting the lower sheet 52 is not particularly limited, but is preferably about 150mm, and particularly preferably 100 mm. In particular, the water retention under load of the superabsorbent nonwoven fabric constituting the lower sheet 52 is preferably 0.13g or more. The upper limit of the water retention under load of the high water-absorbent nonwoven fabric constituting the lower sheet 52 is not particularly limited, but is preferably about 0.30g, and particularly preferably 0.26 g. In particular, the water retention capacity under no load of the super absorbent nonwoven fabric constituting the lower sheet 52 is preferably 0.70g or more. The upper limit of the water retention under load of the high water-absorbent nonwoven fabric constituting the lower sheet 52 is not particularly limited, but is preferably about 1.40g, and particularly preferably 1.20 g.

As the high water absorbent nonwoven fabric constituting the lower sheet 52, a high water absorbent nonwoven fabric similar to the upper sheet 51 can be suitably used. When the joint 54 of the upper sheet 51 and the lower sheet 52 is formed by welding, the high water absorbent nonwoven fabric constituting the lower sheet 52 is preferably a heat-welded fiber such as a polyethylene fiber or a conjugate fiber containing a polyethylene component. The high water-absorbent nonwoven fabric used for the lower sheet 52 is preferably higher in water retention than the upper sheet 51 because it is intended to temporarily store the non-viscous liquid U such as urine. For example, in the super absorbent nonwoven fabric constituting the lower sheet 52, the water retention under load is preferably 2 to 4 times that of the super absorbent nonwoven fabric of the upper sheet 51. More specifically, the weight per unit area of the high water absorbent nonwoven fabric constituting the lower sheet 52 is 1.2 to 1.8 times the weight per unit area of the high water absorbent nonwoven fabric constituting the upper sheet 51, or a plurality of high water absorbent nonwoven fabrics equivalent to the upper sheet 51 can be arranged in a superposed manner as the high water absorbent nonwoven fabric constituting the lower sheet 52.

If the lower sheet 52 has the recesses 50c, the surface area of the lower sheet 52 is increased, and the water holding amount of the lower sheet 52 is preferably increased as compared with the case where the lower sheet 52 is flattened without being subjected to shaping.

The intermediate sheet 80 is not particularly limited as long as it is a nonwoven fabric, but the fineness of the constituent fibers of the nonwoven fabric is preferably about 1.6 to 7.0dtex, and more preferably 5.6 to 6.6 dtex. The nonwoven fabric of the intermediate sheet 80 preferably has a void ratio of 80 to 98%, more preferably 90 to 95%. When the fineness and the void ratio of the intermediate sheet 80 are in this range, the elasticity of the intermediate sheet 80 can be secured as much as possible, and the super absorbent polymer particles 53 can easily enter the fiber gaps of the intermediate sheet 80 before and during absorption of the excretory fluid. Therefore, the fibers of the intermediate sheet 80 spreading in the concave portions 50c ensure a liquid passage toward each superabsorbent polymer particle 53 at the time of absorption, and therefore, even after the superabsorbent polymer particles 53 start to swell, the diffusibility decreasesIs suppressed and gel blocking is hardly generated. The thickness of the intermediate sheet 80 may be appropriately determined in consideration of the depth 50d of the recess 50c, the degree of penetration into the recess 50c, and the like, but the thickness is preferably 10% to 90%, more preferably 70% to 90%, of the depth 50d of the recess 50 c. The basis weight of the intermediate sheet 80 may be appropriately determined for the same reason, but is preferably about 25 to 40g/m within the above thickness range². In order to increase the porosity (increase the fiber gap) of the nonwoven fabric of the intermediate sheet 80, the constituent fibers are preferably crimped fibers. In addition, if the constituent fibers of the nonwoven fabric of the intermediate sheet 80 are hydrophilic fibers (including fibers rendered hydrophilic by a hydrophilic agent), the water retentivity becomes high, and if they are hydrophobic fibers, the diffusibility becomes high. The fiber bonding method of the nonwoven fabric is not particularly limited, but a hot air nonwoven fabric in which fibers are bonded by hot air heating is preferable for the intermediate sheet 80 in order to increase the porosity (increase the fiber gap) and sufficiently bond the fibers to ensure elasticity.

As long as the surface of the intermediate sheet 80 facing the recess 50c enters the recess 50c, it preferably contacts the inner surface of the recess 50c as shown in fig. 13 (a) and (c) and fig. 14 (a) and (c), respectively, but may be separated as shown in fig. 13 (b). When the surface of the intermediate sheet 80 facing the recess 50c is separated from the inner surface of the recess 50c, the separation distance 80s can be determined as appropriate, but is preferably 30% or less of the depth 50d of the recess 50 c. In this way, when a gap is generated in the cavity 55, the convex portion 50p (concave portion 50c) may be crushed in accordance with the gap in the product state.

As shown in fig. 13 (a) to (c) and fig. 14 (a), the intermediate sheet 80 may be bonded to at least one of the upper sheet 51 and the lower sheet 52 by a hot-melt adhesive 80h in both the cavity 55 and the bonding portion 54, or may not be bonded to both the upper sheet 51 and the lower sheet 52 as shown in fig. 14 (c).

It is preferable that almost all (for example, 95% or more) of the super absorbent polymer particles 53 are not fixed to the upper sheet 51, the lower sheet 52, and the intermediate sheet 80 and can move freely. However, a part or almost all (for example, 95% or more) of the super absorbent polymer particles 53 may be bonded or adhered to at least one of the upper sheet 51, the lower sheet 52, and the intermediate sheet 80. Fig. 14 (b) shows an example in which a part of the super absorbent polymer particles 53 is bonded to the lower sheet 52 with an adhesive 53h such as a hot melt adhesive. The super absorbent polymer particles 53 may be agglomerated to some extent. In particular, in the case where the super absorbent polymer particles 53 are freely movable in the chamber 55, if there is a hollow portion in the chamber 55, the super absorbent polymer particles 53 move in the chamber 55 during use, and there is a concern as follows: sound is generated or absorption is hindered due to the presence of the superabsorbent polymer particles 53 biased within the chamber 55. Therefore, to solve this problem, a preferred mode is: as described above, the surface of the intermediate sheet 80 facing the concave portion 50c and the inner surface of the concave portion 50c are brought into contact with each other, in other words, the fibers of the intermediate sheet 80 having a high porosity are filled almost entirely in the chamber 55 including the concave portion 50 c. Thus, the superabsorbent polymer particles 53 are caught by the fibers of the intermediate sheet 80, or pressed against the upper sheet 51 or the lower sheet 52, or both, and therefore, free movement is hardly caused. Therefore, the expansion of the super absorbent polymer particles 53 can be prevented from being hindered, and the generation of sound due to the movement of the super absorbent polymer particles 53 and the absorption due to the misalignment of the super absorbent polymer particles 53 in the chamber 55 can be prevented from being hindered.

As in the examples shown in fig. 13 (a), (b), and fig. 14 (c), the superabsorbent polymer particles 53 are present at the most on the upper surface of the intermediate sheet 80, and decrease from this position toward the lower side, so that when the user touches the outer surface of the diaper with a hand, the intermediate sheet 80 is interposed, and the feel of the brush pull (uncomfortable feeling) of the superabsorbent polymer particles 53 is less likely to be transmitted to the hand, which is preferable. In particular, when the intermediate sheet 80 is a bulky nonwoven fabric having a high porosity, the superabsorbent polymer particles 53 can enter the fiber gaps of the intermediate sheet 80 before and during absorption of the excretory fluid, and thus the absorption rate is further increased. That is, in the initial stage of absorption, absorption proceeds on the upper surface of the intermediate sheet 80 where a large number of superabsorbent polymer particles 53 are distributed, but the speed thereof is limited. Therefore, in the initial stage of the absorption, the excretory fluid also enters the middle sheet 80 having a small number of superabsorbent polymer particles 53, and is absorbed by the superabsorbent polymer particles 53 in the middle sheet 80, temporarily stored until absorbed by the superabsorbent polymer particles 53, or diffused into the surrounding chamber 55. The excretory fluid diffused to the surroundings is absorbed by the superabsorbent polymer particles 53 present in the intermediate sheet 80 therein, or is absorbed by the superabsorbent polymer particles 53 present in a large amount thereabove. Further, in the process of absorbing the excretory fluid by each superabsorbent polymer particle 53, the superabsorbent polymer expands while expanding the fiber space and entering between them, or expands while compressing the intermediate sheet 80. By such an absorption mechanism, the excretory fluid rapidly diffuses over a wide range of the chamber absorbent sheet 50 and is contained in the chamber absorbent sheet 50, and therefore the absorption rate is improved and the backflow prevention property is also excellent. In order to satisfactorily exhibit such an absorption mechanism, it is preferable that the concave portion 50c is formed at least in a portion of the upper sheet 51 constituting each chamber 55.

The degree of distribution of the super absorbent polymer particles 53 in the chamber 55 can be determined as appropriate, but in a normal case, the weight proportion of the super absorbent polymer particles 53 present on the upper surface of the intermediate sheet 80 is preferably 50% or more of the total amount, and the weight proportion of the super absorbent polymer held in the intermediate sheet 80 (i.e., not on the lower sheet 52) is preferably 45% or more of the total amount.

Of course, the distribution of the superabsorbent polymer particles 53 within the chamber 55 is not limited thereto. Therefore, when importance is attached to the absorbency of the high water-absorbent nonwoven fabric constituting the lower sheet 52, it is preferable to adopt a distribution such that: the superabsorbent polymer particles 53 are present most on the upper surface of the lower sheet 52 and decrease therefrom toward the upper side. As shown in fig. 14 (a), the following distribution may be adopted: the superabsorbent polymer particles 53 are present on the upper surface of the intermediate sheet 80 and the upper surface of the lower sheet 52 in a larger amount than in the portion therebetween. Further, although not shown, the following distribution is also possible: the superabsorbent polymer particles 53 are present most at the middle in the thickness direction of the intermediate sheet 80, and decrease from there toward the upper and lower sides. This embodiment can be formed by forming the intermediate sheet 80 as a double-layered nonwoven fabric and sandwiching the super absorbent polymer particles 53 between layers.

The weight per unit area of the super absorbent polymer particles 53 may be determined as appropriate, but may be set to 150 to 250g/m in a normal case, for example². Generally, when the superabsorbent polymer particles 53 have a weight per unit area of less than 150g/m²When the amount exceeds 250g/m, it is difficult to ensure the absorption amount²In this case, when the user touches the outer surface of the product with a hand, the feeling of brush pull (uncomfortable feeling) of the super absorbent polymer particles 53 is easily transmitted to the hand.

The planar shape of the chamber 55 may be determined as appropriate, and may be hexagonal, rhombic, square, rectangular, circular, elliptical, or the like as shown in fig. 8 and the like, but in order to form a more dense arrangement, it is preferably polygonal, and it is preferably arranged without a gap as shown in the illustrated example. The chambers 55 may be arranged by combining a plurality of chambers 55 having different shapes and/or sizes, although not shown, in addition to the arrangement of the chambers having the same shape and the same size.

The planar arrangement of the chambers 55 (that is, the aggregated portions of the super absorbent polymer particles 53 are also the same) may be appropriately determined, but a regularly repeating planar arrangement is preferable, and the planar arrangement may be regularly repeated, such as an oblique square lattice as shown in fig. 12 (a), a hexagonal lattice as shown in fig. 12 (b) (these may also be referred to as a staggered pattern), a square lattice as shown in fig. 12 (c), a rectangular lattice as shown in fig. 12 (d), or a parallel body lattice as shown in fig. 12 (e) (as shown in the figure, a pattern in which a plurality of parallel oblique columns are arranged so as to intersect each other as 2 groups), or the like (including a pattern in which the groups of the oblique columns are inclined at an angle of less than 90 degrees with respect to the stretching direction), patterns, characters, etc.) are regularly repeated.

The dimensions of each chamber 55 can be determined as appropriate, and for example, the dimension 55L in the front-rear direction LD (equal to the dimension of the projection 50p in the front-rear direction LD) can be set to about 6 to 30mm, and the dimension 55W in the width direction WD (equal to the dimension of the projection 50p in the width direction WD) can be set to about 7 to 50 mm. The area of each chamber 55 may be about 31-1650 mm²。

The joining portion 54 for joining the upper sheet 51 and the lower sheet 52 is preferably joined by welding the upper sheet 51 and the lower sheet 52 as in ultrasonic welding or heat sealing, but may be joined by a hot melt adhesive.

The joint portion 54 of the upper sheet 51 and the lower sheet 52 may be formed in a continuous line shape, in addition to a broken line shape (intermittently formed in a direction surrounding each chamber 55) as in the illustrated example, as long as it is arranged so as to surround each chamber 55 and becomes a boundary between adjacent chambers. In the case where the joining portions 54 are formed intermittently, it is preferable that the superabsorbent polymer particles 53 are not present between the joining portions 54 in the direction surrounding the chamber 55, or are less than the inside of the chamber 55 if present. In particular, if the joint portions are provided in a dotted line shape (intermittently), the fiber group of the intermediate sheet extends between the plurality of chambers through between the adjacent joint portions. Accordingly, since the liquid diffusion path is formed between the adjacent joint portions, the absorption rate is improved by improving the liquid diffusibility between the chambers.

As shown in fig. 10, the joint 54 may be a weak joint 54b that can be peeled off by the expansion force of the super absorbent polymer particles 53 in the adjacent chamber 55, or may be a strong joint 54a that is not substantially peeled off by the expansion force of the super absorbent polymer particles 53 in the adjacent chamber 55. In order to cope with the expansion of the superabsorbent polymer particles 53 of the volume of each chamber 55 or more, it is preferable that a part or all of the joint portions 54 be weak joint portions 54 b. By having the weak bond portions 54b, the chambers 55 adjacent to each other with the weak bond portions 54b interposed therebetween can be peeled off and united by the absorption expansion pressure of the super absorbent polymer particles 53 in the chambers 55, thereby forming one large chamber 55.

On the other hand, the strong bonding portion 54a is a portion that does not substantially peel off even if the chambers 55 on both sides thereof absorb expansion, and therefore, it continues in a specific direction, thereby having the following effects: the diffusivity is improved; preventing the flow of the gelled substance of the superabsorbent polymer particles 53; and reducing the contact area on the surface side. Therefore, by combining this with the weak bonding portion, the chamber absorption sheet 50 having various characteristics as described later can be constructed. The bonding portions 54 located on the outermost sides in the width direction WD are preferably strong bonding portions 54a because there is a possibility that the super absorbent polymer particles 53 or the gelled substance thereof may leak to the sides of the chamber absorbent sheet 50 when they are peeled off. From the same viewpoint, it is preferable that the upper sheet 51 and the lower sheet 52 extend outward in the width direction WD to a certain extent from the cavity 55 forming region, and in this extending portion, the edge joining portion 54c is applied in advance for reinforcement.

The difference in bonding strength can be formed simply by changing the area of the bonding portion 54, but is not limited to this, and for example, when the bonding portion 54 is formed by a hot melt adhesive, a method of varying the type of the hot melt adhesive depending on the location may be employed. In particular, in the case where the joint 54 is formed by welding the upper sheet 51 and the lower sheet 52, the weak joint 54b can be formed by enlarging the dot interval 54D by merely forming the joint 54 into a dotted line shape, but since the joint 54 is a portion that becomes a boundary between the adjacent chambers 55, if the dot interval 54D is excessively enlarged, a gap increases at the boundary between the adjacent chambers 55, and the super absorbent polymer particles 53 easily move. Therefore, if the width 54W of the joint 54 is combined with the width of the dot interval 54D to form the weak joint 54b in a dashed line shape, the weak joint 54b is likely to peel off though the gap is small.

The size of the joint 54 that joins the upper sheet 51 and the lower sheet 52 can be determined as appropriate, and for example, the width (the size in the direction perpendicular to the direction surrounding the cavity 55, equal to the interval between the cavities 55) 54W can be set to approximately 1.0 to 1.8 mm. In the case where the joint 54 is formed in a dotted line shape (intermittently in the direction surrounding the cavity 55), it is preferable that the dimension 54L of the joint 54 in the direction surrounding the cavity 55 is about 0.6 to 1.5mm, and the dot interval 54D is about 0.8 to 3.0 mm. In particular, in the case of the strong joining portion 54a, it is preferable that the width 54W is about 1.3 to 1.8mm, the dimension 54L of the joining portion 54 is about 1.0 to 1.5mm, and the dot interval 54D is about 0.8 to 2.0 mm. In the case of the weak bond 54b, the width 54W is preferably about 1.0 to 1.3mm, the dimension 54L of the bond 54 is preferably about 0.6 to 1.0mm, and the dot spacing 54D is preferably about 1.5 to 3.0 mm.

In order to enable the weak bond portions 54b to be peeled off, the type and amount of the super absorbent polymer particles 53 disposed in each chamber 55 can be determined so that the volume of the super absorbent polymer particles 53 in the chamber 55 at the time of saturated absorption is sufficiently larger than the volume of the chamber 55 adjacent to the weak bond portions 54 b. In addition, in order to prevent the strong bond portions 54a from being substantially peeled off, the type and amount of the super absorbent polymer particles 53 disposed in each chamber 55 can be determined as follows: the volume at the time of saturated absorption of the super absorbent polymer particles 53 contained in the bondable chamber 55 is smaller than the volume after bonding of the chamber 55 bondable by peeling off the weak bond 54 b.

The width of the joining portion 54 when the joining portion 54 is formed in a continuous linear shape and the width 54W when the joining portion 54 is formed in a dashed linear shape may be changed in addition to being fixed in the direction surrounding the cavity 55. The shape of each joint portion 54 when the joint portion 54 is formed in a dashed line shape can be appropriately determined, and may be different depending on the portion except for the same shape. In particular, when the shape of each chamber 55 is polygonal, it is preferable to provide the joint portion 54 at least one of the middle position and the vertex position of each side. In addition, in the case of the strong bonding portions 54a, it is preferable to provide them at the respective vertex positions, but in the case of the weak bonding portions 54b, it is preferable that the weak bonding portions 54b are easily peeled off and the chamber 55 is smoothly combined when they are not provided at the respective vertex positions.

As shown in fig. 8 and 11, it is preferable that the chamber absorption sheet 50 is provided with: a longitudinal strong bonding line 58 formed by connecting the strong bonding portion 54a in the front-rear direction LD; and a diffusibility-improving portion 57 formed of low expansion chambers 55s adjacent to both sides thereof. The low expansion chamber 55s of the diffusibility improvement section 57 has a smaller amount of contained superabsorbent polymer particles 53 per unit area than the chambers 55 adjacent to both sides of the diffusibility improvement section 57, and the joint 54 between the low expansion chamber 55s and the chambers 55 adjacent to both sides of the diffusibility improvement section 57 is a weak joint 54 b. In this case, as shown in fig. 10, at the beginning of absorption of the excretory fluid, a wide groove having the diffusion improving section 57 as a bottom is formed due to the difference in the amount of expansion between the diffusion improving section 57 and the surrounding portion, and diffusion of the fluid is promoted by this groove. This state continues until the weak bonding portions 54b between the low expansion chambers 55s of the diffusibility improvement portions 57 and the chambers 55 on both sides thereof are detached by the expansion force of the superabsorbent polymer particles 53 in the chambers 55 around the diffusibility improvement portions 57, and even after the weak bonding portions 54b are detached, the strong bonding portions 54a are not detached, and therefore, although the groove width is narrowed, the grooves with the strong bonding portions 54a as bottoms remain and the diffusibility is maintained. That is, in the initial stage of absorption where diffusion of a large amount of the excreted liquid becomes important, the groove width is large, and thereafter, although the low-expansion chamber 55s of the diffusibility enhancement portion 57 is also integrated with the surrounding chamber 55 to avoid the occurrence of gel blocking or the like, the groove remains at the strong bonding portion 54a, and the diffusibility enhancement effect is maintained.

The amount of the superabsorbent polymer particles 53 contained in the low expansion chamber 55s is preferably not more than 1/3 in the adjacent chamber 55 in terms of weight ratio, and particularly preferably not contained at all.

In fig. 11, the strong bond portions 54a are indicated by thick broken lines, and the other weak bond portions 54b are indicated by thin broken lines, and diagonal line patterns are marked in fig. 11 for the chambers 55 containing the super absorbent polymer particles 53 (i.e., the chambers 55 other than the low expansion chambers 55s and the later-described void chambers 56).

The diffusibility improvement portion 57 may be provided over the entire length of the chamber absorbent sheet 50 as shown in fig. 8, or may be provided only in the middle portion (particularly, over both the front and rear sides including the crotch portion) of the front-rear direction LD as shown in fig. 11. In addition, as shown in fig. 8 and 11, the diffusibility improvement portion 57 is provided at one place in the center of the width direction WD, and may be provided at a plurality of places at intervals in the width direction WD, although not shown.

If the chambers 55 can be combined with each other over the entire front-rear direction LD of the chamber absorbent sheet 50, the gelled product of the super absorbent polymer particles 53 that swell during absorption can move greatly in the front-rear direction LD in the combined chamber 55, and the gelled product may gather at a low portion such as the crotch portion and deteriorate the wearing feeling. Therefore, as shown in fig. 8, the following is a preferable mode: the strong bonding portions 54a are provided in plurality in the front-rear direction LD at intervals in the transverse direction 59 (see fig. 7), which is a portion that is continuous or intermittently (in a continuous line or a broken line) in the width direction WD or in an oblique direction. This can prevent the movement of the gelled substance of the super absorbent polymer particles 53 in the front-rear direction LD by the strong bonding portions 54a that are not substantially peeled off during absorption, and can prevent the deformation of the shape of the chamber absorption sheet 50. Of course, as shown in fig. 11, the transversely strong bonding line 59 may not be provided.

In particular, as in the embodiment shown in fig. 8, if the longitudinal strong bond lines 58, which are portions of the strong bond portions 54a continuous in the front-rear direction LD over the entire length of the chamber absorbent sheet 50, are provided on both sides of the width direction WD, along the side edges of the chambers 55 located outermost in the width direction WD, and also in the middle of the width direction WD, and the transverse strong bond line 59 is a portion continuous in the width direction WD or in an oblique direction over the space between the longitudinal strong bond lines 58 adjacent in the width direction WD, the chambers 55 are not bonded to or above the maximum expansion section 55G surrounded by the strong bond portions 54a, and therefore, the gelled substance of the high-absorbent polymer particles 53 swollen during absorption does not move outside the maximum expansion section 55G, and the shape deformation of the chamber absorbent sheet 50 during absorption can be effectively prevented. Further, the longitudinal direction strong bonding line 58, which is a portion where the strong bonding portion 54a is continuous in the front-rear direction LD, improves the liquid diffusibility in the longitudinal direction, and the lateral direction strong bonding line 59, which is a portion where the strong bonding portion 54a is continuous in the width direction WD or in an oblique direction, improves the liquid diffusibility in the lateral direction. For example, in the embodiment shown in fig. 8, when urine is discharged to the position indicated by reference numeral Z, the urine spreads around this position as shown in fig. 9, and the superabsorbent polymer particles 53 at each position absorb the urine. At this time, as shown in fig. 9 and 10, the chambers 55 in which the swelling pressure of the super absorbent polymer particles 53 is increased cannot be peeled off completely against the swelling pressure at the peripheral weak bond portions 54b, and are united with the adjacent chambers 55. As long as the absorption expansion of the super absorbent polymer particles 53 can peel off the weak bond 54b, the united body continues and can be advanced up to the chamber 55 having the strong bond 54a around it.

The size, shape, and arrangement of the maximum expansion section 55G (that is, the arrangement of the strong bonding portions 54 a) can be determined as appropriate, but if the maximum expansion section 55G is made too small, the meaning of providing the strong bonding portions 54a is lost, and even if the number of chambers 55 is large, the combined shape of the chambers 55 becomes a shape that is difficult to expand when formed to be long and narrow.

In the embodiment shown in fig. 8 to 10, the longitudinal direction strong bonding lines 58 are provided at the center and both side portions in the width direction WD of the chamber absorbent sheet 50, respectively, and the transverse direction strong bonding lines 59 are formed in a zigzag shape extending in the front-rear direction while being repeatedly bent in the left-right direction between the longitudinal direction strong bonding line 58 at the center and the longitudinal direction strong bonding lines 58 at both side portions. As a result, the substantially triangular maximum expansion sections 55G having the apexes at the positions of the central longitudinal strength bonding lines 58 and the substantially triangular maximum expansion sections 55G having the apexes at the positions of the longitudinal strength bonding lines 58 on both side portions are alternately and repeatedly formed in the front-rear direction. When the transverse direction strong bonding lines 59 are formed in a zigzag shape as described above, the transverse direction liquid diffusion can be effectively promoted by the small number of transverse direction strong bonding lines 59, and the maximum expansion section 55G is formed in a substantially triangular shape which is easily expanded, and the increase in the chamber volume with respect to the number of combined chambers 55 is also excellent, which is preferable.

Instead of the low expansion chamber 55s, only the longitudinal strong bonding wire 58 may be provided. In this case, since the strong joining portions 54a do not come off when the excretory fluid is absorbed, the diffusibility due to the remaining grooves having the strong joining portions 54a as bottoms can be improved.

On the other hand, as shown in fig. 8 and the like, a hollow chamber 56 in which the amount of the super absorbent polymer particles 53 contained per unit area is smaller than that of the other chambers may be provided. In fig. 11, the chambers 55 containing the super absorbent polymer particles 53 (i.e., the chambers 55 other than the low expansion chambers 55s and the later-described cavity chambers 56) are marked with diagonal line patterns. Here, the region with the diagonal line pattern in fig. 8 is assumed to be the scattering region 53A of the super absorbent polymer particles 53 at the time of manufacture, and therefore, there is a portion without the diagonal line pattern in the peripheral chamber 55, but when the super absorbent polymer particles 53 can move in the chamber 55, the presence position of the super absorbent polymer particles 53 in the chamber 55 is not fixed in the product, and the super absorbent polymer particles 53 can be distributed over the entire inside of the chamber 55 as in the case of the other figures. The amount of the superabsorbent polymer particles 53 contained in the empty chamber 56 is preferably 1/2 or less of the other chambers in terms of weight ratio, and particularly preferably no contained therein at all. For example, since the front and rear ends of the chamber absorbing sheet 50 are formed by cutting the chamber absorbing sheet 50 at the time of manufacture, if the superabsorbent polymer particles 53 are contained at the positions, the life of the blade of the cutting device may be shortened. Therefore, it is preferable that at least the chamber 55 at the position where the front and rear ends of the chamber absorption sheet 50 pass is the empty chamber 56. Further, by making the chambers 55 on both side portions in the middle of the chamber absorbent sheet 50 in the front-rear direction LD as the empty chambers 56, the portions are less expanded even after absorption, and therefore the chamber absorbent sheet 50 is shaped to fit around the leg portions even after absorption.

In the above example, only the super absorbent polymer particles 53 are contained in the chamber 55, but powder or granules other than the super absorbent polymer particles such as deodorant particles may be contained together with the super absorbent polymer particles 53.

(superabsorbent polymer particles)

As the super absorbent polymer particles 53, super absorbent polymer particles used in such an absorbent article can be used as they are. The particle diameter of the super absorbent polymer particles 53 is not particularly limited, but for example, the proportion of particles exceeding 500 μm is 30 wt% or less, the proportion of particles exceeding 500 μm and exceeding 180 μm is 60 wt% or more, the proportion of particles exceeding 106 μm and being 180 μm or less is 10 wt% or less, and the proportion of particles not exceeding 106 μm is 10 wt% or less. The particle diameters of these particles were measured as follows. That is, a standard sieve (JIS Z8801-1: 2006) of 500. mu.m, 180. mu.m, and 106 μm and a tray were arranged in this order from above, 10g of a sample of superabsorbent polymer particles was put into the uppermost 500 μm sieve, and after sieving (shaking for 5 minutes), the weight of the particles remaining on each sieve was measured. As a result of the screening, the weight ratios of the sample remaining on each of the sieves of 500 μm, 180 μm and 106 μm and the sample remaining on the tray with respect to the input amount were respectively defined as a ratio of particles exceeding 500 μm, a ratio of particles exceeding 500 μm and 180 μm, a ratio of particles exceeding 106 μm and 180 μm or less and a ratio of particles not exceeding 106 μm and 106 μm.

The super absorbent polymer particles 53 may be used without particular limitation, but super absorbent polymer particles having a water absorption capacity of 40g/g or more are preferable. Further, it is preferable that the super absorbent polymer particles 53 are produced by a crushing method because gel blocking is less likely to occur. The super absorbent polymer particles 53 include high absorbent polymer particles such as starch-based, cellulose-based, and synthetic polymers, and high absorbent polymer particles such as starch-acrylic acid (salt) -grafted polymers, saponified products of starch-acrylonitrile copolymers, crosslinked sodium carboxymethylcellulose, and acrylic acid (salt) -based polymers can be used. The shape of the super absorbent polymer particles 53 is preferably a powder shape which is generally used, but other shapes may be adopted.

As the super absorbent polymer particles 53, super absorbent polymer particles having a water absorption rate of 70 seconds or less, particularly 40 seconds or less are preferably used. If the water absorption rate is too slow, so-called back flow in which the liquid supplied into the absorbent body 70 returns to the outside of the absorbent body 70 tends to occur.

In addition, as the super absorbent polymer particles 53, super absorbent polymer particles having a gel strength of 1000Pa or more are preferably used. This can effectively suppress the sticky feeling after the liquid absorption.

(packaging sheet)

As shown in fig. 3 and fig. 15 (a), the absorbent body 70 can be wrapped with a wrapping sheet 45. In this case, in addition to winding one packaging sheet 45 in a roll shape so as to surround the front and back surfaces and both side surfaces of the

absorbent body

70, 2 packaging sheets 45 can be used to package the absorbent body while sandwiching the absorbent body from the front and back surfaces. As the packaging sheet 45, a tissue paper (tissue paper), particularly, crepe paper, nonwoven fabric, polyethylene laminated nonwoven fabric, a sheet with small holes, or the like can be used. Among these, a sheet that does not cause the super absorbent polymer particles 53 to fall out is preferable. When a nonwoven fabric is used for the packaging sheet 45, a hydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularly suitable, and polypropylene, a polyethylene/polypropylene composite material, or the like can be used as the material. The weight per unit area of the nonwoven fabric for the packaging sheet 45 is preferably 5 to 40g/m²Particularly preferably 10 to 30g/m²。

As shown in fig. 15 (b), the wrapping sheet 45 is preferably wound from the back surface of the absorbent body 70 to both side portions of the upper surface of the absorbent body 70 via both sides in the width direction WD of the absorbent body 70, and a region 45S not covered with the wrapping sheet 45 is preferably provided in the middle portion in the width direction WD of the upper surface of the absorbent body 70. The absorbent body 70 is usually covered with the wrapping sheet 45 in order to prevent leakage of the super absorbent polymer particles during production, before use, or after absorption, but when the absorbency of the viscous liquid in the absorbent body 70 is taken into consideration, it is desirable that the top sheet 51 promptly comes into contact with the viscous liquid N. Therefore, as shown in fig. 15 (b), the covering area of the wrapping sheet 45 is preferably limited so that the upper sheet 51 is exposed on the upper surface of the absorbent body 70. Even with such a structure, the top sheet 51 is based on a high water-absorbent nonwoven fabric having a high degree of klem water absorption (i.e., a dense nonwoven fabric), and therefore, the effect of preventing leakage of superabsorbent polymer particles can be exhibited substantially the same as the structure in which the entire absorbent body 70 is covered with the wrapping sheet 45.

< description of words in the specification >)

When the following terms are used in the specification, they have the following meanings unless otherwise specified in the specification.

"MD direction" and "CD direction" refer to a conveying direction (MD direction) in a manufacturing apparatus and a transverse direction (CD direction) perpendicular to the conveying direction, and either one of them becomes a front-back direction of a product, and the other becomes a width direction of the product. The MD direction of a nonwoven fabric is the direction in which the fibers of the nonwoven fabric are oriented. The fiber orientation is a direction along which the fibers of the nonwoven fabric are oriented, and can be determined by, for example, the following measurement method: a measurement method according to a fiber orientation test method, wherein the fiber orientation test method is a test method based on a zero distance tensile strength of TAPPI standard method T481; alternatively, a simple measurement method for determining the fiber orientation direction from the ratio of the tensile strength in the front-back direction and the width direction.

"front-rear direction" means a direction (longitudinal direction) indicated by reference numeral LD in the drawing, "width direction" means a direction (left-right direction) indicated by WD in the drawing, and the front-rear direction is perpendicular to the width direction.

"front side" means the side that is closer to the wearer's skin when worn, and "back side" means the side that is farther from the wearer's skin when worn.

"front" refers to the side of the component that is closer to the wearer's skin when worn, and "back" refers to the side that is further from the wearer's skin when worn.

"expanded state" refers to a state of flat expansion without contraction and relaxation.

"elongation" means a value when the natural length is 100%. For example, an elongation of 200% means the same as an elongation magnification of 2 times.

"Artificial urine" means that urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt% and ion-exchanged water: 97.09 wt% was used at a temperature of 37 ℃ unless otherwise specified.

The "gel strength" is measured as follows. To 49.0g of the artificial urine, 1.0g of a super absorbent polymer was added and stirred by a stirrer. The resultant gel was allowed to stand in a constant temperature and humidity bath at 40 ℃ X60% RH for 3 hours and then returned to normal temperature, and the gel strength was measured by a curdometer-MAX ME-500 (manufactured by I.techno Engineering Co.).

The "weight per unit area" is measured as follows. The sample or test piece is dried and placed in a laboratory or apparatus in a standard state (the temperature in the test site is 23. + -. 1 ℃ C., and the relative humidity is 50. + -. 2%) so as to be in a constant state. The preliminary baking means that the sample or the test piece is made constant in an environment at a temperature of 100 ℃. In addition, the fibers having a official moisture regain of 0.0% may not be subjected to preliminary drying. Using a template (100 mm. times.100 mm) for sample selection, a sample having a size of 100 mm. times.100 mm was cut out from the test piece in a constant state. The weight of the sample was measured, and the weight per square meter was calculated as a weight per unit area by 100 times.

"thickness" is measured using an automatic thickness measuring apparatus (KES-G5 Portable compression tester) at a load of 0.098N/cm²The pressure area is 2cm²Is automatically measured under the conditions of (1).

The "void ratio" is measured by the following method. That is, the portion of the intermediate sheet other than the joint portion was cut into a rectangular shape to obtain a sample. The length, width, thickness, weight of the test specimen were measured. The virtual weight when the porosity was 0% was calculated from the material density of the nonwoven fabric in the same volume as the sample. The void ratio was obtained by substituting the sample weight and the virtual weight into the following equation.

Void ratio [ ((virtual weight-sample weight)/virtual weight) ] x 100

The "water absorption" is measured according to JIS K7223-1996 "Water absorption test method of super absorbent resin".

The "water absorption rate" is the "time to end point" when JIS K7224-1996 "Water absorption Rate test method for superabsorbent resin" was carried out using 2g of a superabsorbent polymer and 50g of physiological saline.

"Cramer water absorption" means a value determined by JIS P8141: klemm water absorption measured by the "paper and board water absorption test method-klemm method" specified in 2004.

The "water retention amount" refers to a value measured by the following method. 10cm in MD direction was prepared by 10cm in CD direction (area: 100 cm)²) The test piece of (4), and the weight before absorption was measured. Next, after the test piece was immersed in artificial urine for 5 seconds, any 1 corner portion was gently pinched with the thumb and forefinger (gently pinched so as not to squeeze out water as much as possible), and the opposite corner portion was lifted up so as to face downward, and left for 30 seconds to drop water droplets. Then, in order to measure the "water retention under load", 8 sheets of filter paper (150 mm in length × 150mm in width) were laid one on top of another, a test piece was placed, a quadrangular prism-shaped weight (weight: 3kg) having a bottom surface of 100mm in length × 100mm in width was placed so as to apply a load to the entire upper surface of the test piece, and the weight was removed at the time of 5 minutes to measure the weight of the test piece after absorption. In the case of measuring the "water retention under no load", 8 sheets of filter paper were laid one on top of the other, and then the test piece was placed thereon, and the weight of the test piece after absorption was measured at the time when 5 minutes passed. Based on these measurement results, the difference between the weight after absorption and the weight before absorption was measured at every 10cm²The values obtained by converting the area of (b) are referred to as "water retention under load" and "water retention under no load".

The dimensions of each portion are not particularly described, but are dimensions in the expanded state rather than the natural length state.

The test or measurement is carried out in a laboratory or apparatus in a standard state (in the test site, the temperature is 23 ± 1 ℃, and the relative humidity is 50 ± 2%) without describing the environmental conditions in the test or measurement.

Industrial applicability

The present invention can be used not only in a tape-type disposable diaper as in the above-described example, but also in all absorbent articles such as a pants-type disposable diaper, a pad-type disposable diaper, and a sanitary napkin.

Description of the reference symbols

LD: a front-back direction; n: a viscous liquid; u: a non-viscous liquid; WD: a width direction; 11: a liquid-impermeable sheet; 12: a non-woven fabric is externally arranged; 12T: target sheet; 13: a fastening tape; 13A: a card-holding section; 13B: a belt main body portion; 13C: a belt mounting portion; 30: a topsheet; 40: an intermediate sheet; 42: high water absorption non-woven fabrics; 42 a: a pulp layer; 42 b: a support layer; 45: packaging the sheet; 50: a chamber absorber plate; 50 c: a recess; 50 d: depth; 50 p: a convex portion; 51: loading the wafer; 52: carrying out sheet discharging; 53: superabsorbent polymer particles; 54: a joint portion; 54 a: a strong joint portion; 54 b: a weak bond; 54 c: an edge joint portion; 55: a chamber; 55G: maximally expanding the partitions; 55 s: a low expansion chamber; 56: a hollow chamber; 57: a diffusivity-improving section; 58: a longitudinal strong bond line; 59: a transverse strong bond line; 60: raising a gather portion; 62: a gusset; 70: an absorbent body; 80: an intermediate sheet.

Claims

1. An absorbent article characterized in that,

2. The absorbent article of claim 1,

the high water absorption non-woven fabric forming the upper sheet contains more than 50% of pulp fiber or rayon fiber, and has a weight per unit area of 25g/m²～50g/m²The wet nonwoven fabric of (1).

3. The absorbent article of claim 2, wherein,

the wet nonwoven fabric comprises: a support layer comprising long fibers of a synthetic resin; and a pulp layer composed only of pulp fibers, which is located at a position most on the front surface side.

4. The absorbent article according to any one of claims 1 to 3, wherein,

the chamber absorbent sheet contains superabsorbent polymer particles adjacent to the back surface of the upper sheet.

5. The absorbent article according to any one of claims 1 to 4, wherein,

the upper sheet is pushed upward at a portion thereof located in each chamber, and a pair of concave and convex portions is formed on an upper surface and a lower surface of the upper sheet.

6. The absorbent article according to any one of claims 1 to 5, wherein,

the absorbent article comprises a liquid-impermeable sheet disposed on the back side of the absorbent body,

7. The absorbent article of claim 6,

the lower sheet is pushed downward at portions thereof located in the respective chambers, and a pair of concave portions and convex portions are formed on an upper surface and a lower surface of the lower sheet.