WO2024135458A1

WO2024135458A1 - Absorbent, and absorbent article

Info

Publication number: WO2024135458A1
Application number: PCT/JP2023/044459
Authority: WO
Inventors: 貴志野本; 明寛木村; 耕出谷; 貴司野口; 友美衛藤
Original assignee: ユニ・チャーム株式会社
Priority date: 2022-12-20
Filing date: 2023-12-12
Publication date: 2024-06-27

Abstract

An absorbent (10) is used in an absorbent article (1), the absorbent being characterized by: being constituted of one or more nonwoven fabrics (2, 3) comprising a plurality of fibers (2f, 3f) including latently-crimped fibers; having voids formed by the plurality of fibers (3f); and the value obtained by dividing the weight of the latently-crimped fibers by the weight of the plurality of fibers being 70% or greater.

Description

Absorbent bodies and absorbent articles

The present invention relates to an absorbent body and an absorbent article.

　Conventionally, absorbent articles such as sanitary napkins, disposable diapers, and absorbent pads are known. For example, Patent Document 1 discloses a sanitary napkin having a top sheet arranged on the skin contact side, a back sheet arranged on the non-skin contact side, and an absorbent body arranged between the top sheet and the back sheet. The absorbent body in Patent Document 1 is made of pulp fibers, etc.

JP 2013-176412 A

When an absorbent article such as a sanitary napkin as described in Patent Document 1 is worn, the humidity increases when excrement is absorbed, making the wearer prone to feel stuffy, and the absorbent article may become wrinkled or deformed when worn for a long period of time, causing discomfort to the wearer. For this reason, it is desirable to improve the breathability of the absorbent article while reducing deformation of the absorbent article even when worn.

The present invention was made in consideration of the above problems, and its purpose is to provide an absorbent body that improves breathability while reducing twisting and deformation.

The main invention for achieving the above-mentioned object is an absorbent body for use in absorbent articles, which is composed of at least one nonwoven fabric having a plurality of fibers including latent crimp fibers, has voids formed by the plurality of fibers, and is characterized in that the weight of the latent crimp fibers divided by the weight of the plurality of fibers is 70% or more.
Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings.

The present invention makes it possible to create an absorbent that retains excrement in the voids formed by the fibers, while improving breathability and reducing twisting and deformation.

FIG. 2 is a plan view of the sanitary napkin 1 as seen from the skin side. 2 is a schematic cross-sectional view of the napkin 1 taken along the line AA. 1A and 1B are diagrams illustrating the configuration of a napkin 1. 1 is a diagram illustrating an absorbent layer 10 of a napkin 1. FIG. Fig. 5A is a diagram showing a schematic cross section of the skin side layer 2. Fig. 5B is a diagram showing a schematic cross section of the non-skin side layer 3. 5 is a schematic cross-sectional view taken along line BB in FIG. 4. FIG. 2 is a diagram illustrating the napkin 1 30 minutes after horse blood is dripped onto it. FIG. 4 is a diagram illustrating a measurement region Y. FIG. 13 is a diagram for explaining an outline of a method for evaluating the narrowness of a gap Z. FIG. 2 is a diagram showing the measurement results of an absorption test of the absorbent layer 10. Fig. 11A is a diagram showing the measurement results of the bending property of the absorbent layer 10 by the KES method. Fig. 11B is a diagram showing the measurement results of the compression property of the absorbent layer 10 by the KES method. 1 is a diagram showing the measurement results of an elongation test of the absorbent layer 10. FIG. 11A and 11B are diagrams illustrating a modified example of a napkin 100 according to the present embodiment. FIG. 2 is a diagram illustrating the skin side layer 2 of the napkin 100.

At least the following points will become apparent from the description of this specification and the accompanying drawings.
(Aspect 1)
The absorbent body is used in absorbent articles and is composed of at least one nonwoven fabric having a plurality of fibers including latent crimp fibers, has voids formed by the plurality of fibers, and is characterized in that the weight of the latent crimp fibers divided by the weight of the plurality of fibers is 70% or more.

The absorbent body of aspect 1 can retain excrement in the voids formed by the fibers, while improving breathability and reducing wrinkling and deformation.

(Aspect 2)
The absorbent body according to aspect 1, wherein the air flow resistance is 0.32 kPa·s/m or less.

The absorbent body of aspect 2 can improve the breathability of the absorbent article compared to when the airflow resistance value is greater than 0.32 kPa·s/m, thereby reducing discomfort for the wearer of the absorbent article.

(Aspect 3)
3. The absorbent body according to

claim

1 or 2, wherein the plurality of fibers are not fused to one another.

The absorbent of aspect 3 reduces the risk that the fused parts will hinder the absorption and diffusion of excrement.

(Aspect 4)
The absorbent body is described in any one of aspects 1 to 3, and has a thickness direction and voids formed by the plurality of fibers, and when the absorbent body is divided into three equal parts in the thickness direction, with the region closest to the skin being the skin side region, the region closest to the skin being the non-skin side region, and the region between the skin side region and the non-skin side region being the intermediate region, the average narrowness of the non-skin side regions in a narrowness evaluation test for quantitatively evaluating the narrowness of the voids is smaller than the average narrowness of the skin side regions in the narrowness evaluation test.

The absorbent of aspect 4 makes it easier for waste to be drawn from the skin-side region to the non-skin-side region by capillary action and to be diffused in the non-skin-side region, reducing the risk of waste remaining on the surface of the skin-side region.

(Aspect 5)
The absorbent body is described in any one of aspects 1 to 4, and has a thickness direction and voids formed by the plurality of fibers, and when the absorbent body is divided into three equal parts in the thickness direction, with the region closest to the skin being the skin side region, the region closest to the skin being the non-skin side region, and the region between the skin side region and the non-skin side region being an intermediate region, the void ratio of the non-skin side region in a void ratio evaluation test for quantitatively evaluating the ratio of the voids in a specified region is smaller than the void ratio of the skin side region in the void ratio evaluation test.

The absorbent of aspect 5 allows excrement to be drawn into the non-skin side area more easily than into the skin side area due to capillary action, and is more easily dispersed in the non-skin side area, reducing the risk of liquid remaining on the surface of the skin side area.

(Aspect 6)
The absorbent body is described in any one of aspects 1 to 5, and has a thickness direction and voids formed by the plurality of fibers. When the absorbent body is divided into three equal parts in the thickness direction, with the region closest to the skin being the skin side region, the region closest to the skin being the non-skin side region, and the region between the skin side region and the non-skin side region being an intermediate region, the hydrophilicity of the skin side region is lower than the hydrophilicity of the non-skin side region.

The absorbent of aspect 6 makes it easier for excrement absorbed in the skin-side region to be directed toward the non-skin-side region and to be dispersed in the non-skin-side region, thereby reducing the risk of excrement remaining on the surface of the skin-side region and reducing discomfort for the wearer.

(Aspect 7)
An absorbent body as described in any one of aspects 1 to 6, which has a thickness direction and has voids formed by the plurality of fibers, and when the absorbent body is divided into thirds in the thickness direction, with the region closest to the skin being the skin side region, the region closest to the skin being the non-skin side region, and the region between the skin side region and the non-skin side region being an intermediate region, at least a portion of the fibers in the non-skin side region are more hydrophilic than the fibers in the skin side region, and a portion of the fibers in the non-skin side region are exposed on the skin side surface of the absorbent body.

According to the absorbent of aspect 7, the exposed fibers of the non-skin side region tend to draw the excrement absorbed from the skin side toward the non-skin side region, facilitating the diffusion of the excrement within the non-skin side region, and reducing the risk of liquid remaining on the surface of the skin side region.

(Aspect 8)
An absorbent body as described in any one of aspects 1 to 7, having a thickness direction, wherein a first region is a region closer to the skin than the center in the thickness direction of the absorbent body, and a second region is a region closer to the non-skin side than the center in the thickness direction of the absorbent body, and the maximum fiber thickness of the first region is greater than the maximum fiber thickness of the second region.

In the absorbent of aspect 8, the thicker the fibers, the larger the voids formed by the fibers tend to be, making it easier for waste material to be drawn into the second region, which has smaller voids, and easier for waste material to be dispersed in the second region, reducing the risk of waste material continually coming into contact with the wearer and reducing discomfort to the wearer.

(Aspect 9)
Aspect 9. The absorbent body according to any one of aspects 1 to 8, wherein the basis weight of the plurality of fibers of the absorbent body is 80 gsm or more and 350 gsm or less.

The absorbent body of aspect 9 is more likely to absorb excrement than when the fiber basis weight of the absorbent body is less than 80 gsm, and the risk of the absorbent body becoming excessively thick or hard is reduced compared to when the fiber basis weight of the absorbent body is greater than 350 gsm.

(Aspect 10)
The absorbent body according to any one of aspects 1 to 9 has a longitudinal direction, a width direction, and a thickness direction, the longitudinal length of the absorbent body is longer than the width direction length, and the bending stiffness B of a central portion of the absorbent body in the longitudinal direction and in the width direction is 1.2 gf·cm ² /cm or less, as measured by the KES method.

According to the absorbent body of aspect 10, the absorbent article can be made more flexible than when the flexural rigidity B of the absorbent body is greater than 1.2 gf·cm ² /cm, and therefore the absorbent article can more easily conform to the body of the wearer wearing the absorbent article.

(Aspect 11)
The absorbent body according to any one of aspects 1 to 10 has a longitudinal direction, a width direction, and a thickness direction, the length of the absorbent body in the longitudinal direction is longer than the length of the width direction, and the bending hysteresis 2HB of the central part of the absorbent body in the longitudinal direction and the central part in the width direction, as measured by the KES method, is 0.93 gf·cm ² /cm or less.

According to the absorbent body of aspect 11, the absorbent body that has been deformed while being worn can be more easily returned to its original shape than when the bending hysteresis 2HB of the absorbent body is greater than 0.93 gf·cm ² /cm, thereby reducing the discomfort felt by the wearer due to the deformation of the absorbent body and the risk of excrement leaking from the absorbent body.

(Aspect 12)
The absorbent body according to any one of aspects 1 to 11, which has a longitudinal direction, a width direction, and a thickness direction, the length of the absorbent body in the longitudinal direction is longer than the length of the width direction, and the linearity LC of the compression characteristics of the absorbent body in the longitudinal direction and the width direction, as measured by the KES method, is 0.6 or more at a central portion of the absorbent body.

According to the absorbent body of aspect 12, the absorbent body can be made more compressively rigid than when the linearity LC of the compression characteristics of the absorbent body is less than 0.6, and deformation of the absorbent body can be reduced, thereby reducing the discomfort felt by the wearer due to deformation of the absorbent body and reducing the risk of excrement leaking from the absorbent body.

(Aspect 13)
An absorbent body according to any one of aspects 1 to 12, which has a longitudinal direction, a width direction, and a thickness direction, the longitudinal length of the absorbent body is longer than the width direction length, and the compression resilience RC of the central portion of the absorbent body in the longitudinal direction and the central portion of the width direction, as measured by the KES method, is 38.0% or more.

The absorbent body of aspect 13 allows the absorbent body to return to its original shape when worn more easily than when the compression resilience of the absorbent body is less than 38%, which reduces the discomfort felt by the wearer due to deformation of the absorbent body and reduces the risk of excrement leaking from the absorbent body.

(Aspect 14)
14. The absorbent body according to any one of aspects 1 to 13, wherein, in an elongation test for measuring the magnitude of force required to elongate the length of the absorbent body in the longitudinal direction to a length that is 1.3 times the length of the absorbent body in the longitudinal direction, a value obtained by dividing the value of the magnitude of force obtained in a 10th measurement of the elongation test of the absorbent body by the value of the magnitude of force obtained in a first measurement of the elongation test of the absorbent body is 50% or more.

In the absorbent of aspect 14, the value obtained by dividing the force magnitude value from the 10th measurement in the elongation test by the force magnitude value from the first measurement is 50% or more, which reduces damage to the absorbent even when worn, and makes it possible to produce an absorbent article that is more likely to follow the shape and movements of the wearer's body than when the value obtained by dividing the force magnitude value from the 10th measurement in the elongation test by the force magnitude value from the first measurement is less than 50%.

(Aspect 15)
14. An absorbent article according to any one of aspects 1 to 13, which has a longitudinal direction, a width direction, and a thickness direction, and the longitudinal length of the absorbent body is longer than its width direction length, and when viewed in the thickness direction, the central portion of the absorbent article in the longitudinal direction and the central portion of the width direction are defined as a predetermined region, and the weight of the predetermined region before it absorbs distilled water is defined as a pre-absorption weight, and the weight of the predetermined region after it is immersed in distilled water for 60 seconds and then pulled out of the distilled water and hung for 90 seconds is defined as a post-absorption weight, and when the value obtained by subtracting the pre-absorption weight from the post-absorption weight is defined as the absorption weight of the distilled water, the value obtained by dividing the absorption weight by the pre-absorption weight is 5 or more.

According to the absorbent article of aspect 15, the absorbent article is more likely to diffuse the absorbed liquid over a wider area in the absorbent body while still maintaining its liquid absorption function, compared to when the value obtained by dividing the absorbed weight by the weight before absorption is less than 5.

====Embodiment====
An embodiment of the absorbent article according to the present invention will be described taking a sanitary napkin 1 (hereinafter also referred to as "napkin 1") as an example of the absorbent article according to the present invention. However, the absorbent article according to the present invention may be a pants-type disposable diaper or a tape-type disposable diaper for adults or infants, sanitary shorts, sanitary napkin, light incontinence pad, absorbent pad, disposable diaper or absorbent sheet for animals, drip sheet, etc. In the case of a drip sheet or the like, the "wearing state" in the following embodiment becomes the "use state" and the wearer becomes the "user, etc." Hereinafter, the wearing state is also referred to as the "use state" and the wearer is also referred to as the "user, etc."

<<<<Configuration of sanitary napkin 1>>>
FIG. 1 is a plan view of a sanitary napkin 1 (hereinafter also referred to as "napkin") as seen from the skin side. FIG. 2 is a schematic cross-sectional view of the napkin 1 taken along the line A-A. FIG. 3 is a diagram for explaining the configuration of the napkin 1. The napkin 1 has a longitudinal direction, a width direction, and a thickness direction which are perpendicular to one another. In the thickness direction, the side that contacts the wearer's skin is the skin side, and the opposite side is the non-skin side. The skin side in the thickness direction is the side that receives excrement (liquid) when worn, and is also referred to as the "absorbent side". The non-skin side in the thickness direction is the side opposite to the absorbent side, and is also referred to as the "non-absorbent side". The center line C-C shown in FIG. 1 etc. indicates the center (central position) of the napkin 1 in the width direction.

The napkin 1 has a skin-side layer (nonwoven fabric sheet) 2, a non-skin-side layer (nonwoven fabric sheet) 3, a back sheet 4, and a side sheet 5. As shown in FIG. 3 etc., the napkin 1 is layered in the thickness direction in the following order from the skin side: side sheet 5, skin-side layer 2, non-skin-side layer 3, and back sheet 4. Each member layered in the thickness direction is fixed together with an adhesive such as a hot melt adhesive.

The skin-side layer 2 is the skin-side sheet located closest to the skin in the widthwise center of the napkin 1, and is an absorbent member that abuts against the excretory opening when worn and receives excrement discharged from the excretory opening. The skin-side layer 2 is substantially rectangular in shape and is long in the longitudinal direction, with the longitudinal length L2 being longer than the widthwise length W2. By providing the skin-side layer 2 at the wearer's crotch position when the napkin 1 is worn, when the napkin 1 absorbs excrement, the skin-side layer 2 can absorb the excrement and diffuse the absorbed excrement toward the non-skin-side layer 3. This can reduce discomfort to the wearer caused by excrement leaking from the napkin 1 or excrement remaining locally on the surface of the skin-side layer 2, etc.

The non-skin side layer 3 is a non-skin side sheet provided between the skin side layer 2 and the back sheet 4 in the thickness direction, and the non-skin side layer 3 is slightly smaller than the skin side layer 2 in a plan view. The non-skin side layer 3 is substantially rectangular in shape and is long in the longitudinal direction, and the longitudinal length L3 is longer than the widthwise length W3. The non-skin side layer 3 is an absorbent member that absorbs the excrement absorbed by the skin side layer 2 and retains the excrement. By providing the non-skin side layer 3 at the crotch position of the wearer when the napkin 1 is worn, when the napkin 1 absorbs excrement, the non-skin side layer 3 can absorb the excrement and disperse the excrement within the non-skin side layer 3. This can reduce discomfort to the wearer caused by excrement leaking from the napkin 1 or excrement remaining locally on the surface of the skin side layer 2, etc.

The skin-side layer 2 and the non-skin-side layer 3 are nonwoven fabrics (nonwoven fabric sheets) made of latent crimped fibers 2f and latent crimped fibers 3f (see FIG. 5), respectively. In this embodiment, the skin-side layer 2 and the non-skin-side layer 3 are nonwoven fabrics made of only latent crimped fibers (latent crimped fibers are 100%). However, the layers (nonwoven fabrics) making up the skin-side layer 2 and the non-skin-side layer 3 may use, in addition to latent crimped fibers, fibers made of polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters (PET and PBT), polyamides, etc., and composite fibers of these, as well as hydrophilic fibers such as rayon, pulp, and cotton. Hereinafter, the latent crimped fibers 2f and the latent crimped fibers 3f are also simply referred to as "fibers 2f" and "fibers 3f".

"Nonwoven fabric" refers to a fiber sheet, web, or batt in which the fibers are oriented in one direction or randomly and are bonded by entanglement and/or fusion and/or adhesion (JIS L0222:2001 Nonwoven fabric terminology 101). In other words, nonwoven fabric is a sheet in which the fibers are integrated without being woven, with a breaking strength of 5 [N]/25 mm or more. The breaking strength can be measured by a well-known method, for example, by the following method. A tensile tester (Shimadzu Corporation: Autograph, AGS-1kNG) equipped with a load cell with a maximum load capacity of 50 N is used. When measuring the separation strength of a nonwoven fabric sheet, one chuck grips the tip of one side of the nonwoven fabric sheet in the longitudinal or transverse direction, and the other chuck grips the other side of the nonwoven fabric sheet. Using a tensile tester, the two chucks are pulled at a constant speed (e.g., 100 mm/min) so that the distance between them increases, while the load applied to the two chucks is measured. The load at which the nonwoven fabric sheet breaks is the breaking strength.

Examples of nonwoven fabrics include nonwoven fabrics obtained by the meltblown method (meltblown nonwoven fabric), nonwoven fabrics obtained by the electrospinning method (electrospinning nonwoven fabric), nonwoven fabrics obtained by the spunbond method (spunbond nonwoven fabric), nonwoven fabrics produced by the air-through method (air-through nonwoven fabric), nonwoven fabrics produced by the spunlace method (spunlace nonwoven fabric), nonwoven fabrics produced by the needlepunch method (needlepunch nonwoven fabric), or laminates of two or more of these nonwoven fabrics, or laminates of these nonwoven fabrics with other nonwoven fabrics or other materials. The skin-side layer 2 and the non-skin-side layer 3 of this embodiment are each a spunlace nonwoven fabric in which no adhesive is used and the fibers are entangled by a water flow.

The nonwoven fabric sheet of the skin side layer 2 of the napkin 1 of this embodiment is formed by the spunlace method through the following steps.
(a) First, hydrophilic fibers 2fb (fibers 2f forming at least a part of the non-skin side region Rd described below) are processed by a carding machine or the like to form a non-skin side fiber web having a form such as a carded web.
(b) Next, the hydrophobic fibers 2fa (fibers 2f forming at least a part of the skin side region Ru) are processed using a carding machine or the like to obtain a skin side fiber web having the form of a carded web or the like, which is then fed onto the non-skin side fiber web while transporting the non-skin side fiber web, and laminated to obtain a laminated web.
(c) A high-pressure water jet treatment such as a water jet is applied from the skin side to the non-skin side in the thickness direction of the laminated web to entangle the fibers between each fiber layer and the fibers between each web, thereby obtaining a laminate.
(d) Finally, the laminate is placed in a dryer and heated to a temperature at which the latent crimpable fibers can shrink, thereby obtaining an integrated nonwoven fabric sheet (skin side layer 2). This nonwoven fabric sheet has voids formed by the plurality of fibers 2f.

The nonwoven fabric sheet of the non-skin side layer 3 of the napkin 1 of this embodiment is formed in the same manner as the nonwoven fabric sheet of the skin side layer 2. However, the nonwoven fabric sheet of the non-skin side layer 3 differs from the skin side layer 2 in that it does not use hydrophobic fibers, but is made by laminating only a web of hydrophilic fibers 3f.

Latently crimped

fibers

2f and 3f are fibers that shrink when heated to develop a helical shape. Examples of latent crimpable fibers include side-by-side composite fibers in which high and low shrinkage components are arranged in parallel, and eccentric core-sheath composite fibers in which the high shrinkage component is the core and the low shrinkage component is the sheath, with the centers of gravity of both components not overlapping at a single point. When the crimp of the latent crimpable fiber is developed, the latent crimpable fiber shrinks, for example, into a coil shape.

As the multiple resins with different thermal shrinkage rates or thermal expansion rates that form the

latent shrinkage fibers

2f and 3f, any combination of resins with different thermal shrinkage rates or thermal expansion rates can be used without any particular limitations, and may be a combination of the same or a single resin, or a combination of different resins. Specific examples of combinations of resins with different thermal shrinkage rates or thermal expansion rates that form the latent shrinkage fibers include combinations of polyester resins and combinations of polyamide resins.

The nonwoven fabric of the skin side layer 2 and the non-skin side layer 3 in this embodiment is a combination of polyester resins (single component resins), specifically, a latent shrink fiber of a combination of polyethylene terephthalate (PET) and modified PET is used. The modified PET is PET modified by copolymerizing ethylene glycol and terephthalic acid, which are the components of PET, with a minor amount of a diol component other than ethylene glycol or a dicarboxylic acid component other than terephthalic acid. Specific examples of diol components other than ethylene glycol include, for example, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, etc. Specific examples of dicarboxylic acid components other than terephthalic acid include, for example, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, etc. Then, a web made of latently crimpable fibers of a combination of PET and modified PET is formed using a web forming means such as a carding machine, the fibers of this web are entangled by the spunlace method to form a nonwoven fabric, and this is heated to a predetermined temperature to cause the latently crimpable fibers to crimp, thereby producing the nonwoven fabric of the skin side layer 2 and the non-skin side layer 3. As a result, the basis weight of the latently crimped fibers in the nonwoven fabric after heating is greater than the basis weight of the latently crimpable fibers in the nonwoven fabric before heating. In other words, the nonwoven fabric shrinks due to the crimping of the latently crimpable fibers, and the basis weight of the fibers increases.

The skin-side layer 2 and the non-skin-side layer 3 are each an absorbent layer 10 having a predetermined thickness that is liquid-permeable and has the ability to absorb and retain liquid. In this embodiment, the absorbent of the present invention will be described as the absorbent layer 10. FIG. 4 is a diagram illustrating the absorbent layer 10 of the napkin 1. In the napkin 1, the skin-side layer 2 is a skin-side sheet that contacts the wearer's skin, and is a member that first receives excrement when worn, absorbing the received excrement within the skin-side layer 2 and allowing it to permeate towards the non-skin side. The non-skin-side layer 3 is a member that absorbs and retains excrement that has permeated from the skin-side layer 2.

As shown in FIG. 5, the skin side layer 2 and the non-skin side layer 3 each have a void formed by a plurality of fibers (latently crimped fibers) 2f, 3f. FIG. 5A is a schematic diagram of the cross section of the skin side layer 2, and FIG. 5B is a schematic diagram of the cross section of the non-skin side layer 3, and the dimensions are not necessarily accurate. The voids in the skin side layer 2 and the non-skin side layer 3 may be voids between discontinuous fibers (a plurality of fibers), voids formed by a single continuous fiber being curved or spiral, or voids formed by a combination of these. The voids formed by a plurality of

fibers

2f, 3f refer to spaces/areas in the skin side layer 2 and the non-skin side layer 3 where a plurality of

fibers

2f, 3f are not provided. The voids may be not only spaces surrounded by the

fibers

2f, 3f or spaces closed by the fibers, but also spaces that are at least partially open in the voids formed by the

fibers

2f, 3f.

The skin-side layer 2 and the non-skin-side layer 3 each contain latent

crimped fibers

2f and 3f, and as a result of the crimping of the

fibers

2f and 3f, the

fibers

2f and 3f form a spiral shape that intertwines and threads between them. For example, the distance between the

fibers

2f and 3f and the

fibers

2f and 3f may be shortened by the crimping, or another fiber may be inserted between the shortened

fibers

2f and 3f and the

fibers

2f and 3f, further reducing the gap between the

fibers

2f and 3f and the

fibers

2f and 3f. Therefore, the gap formed by the

fibers

2f and 3f containing latent crimped fibers is smaller than the gap formed by multiple fibers in a typical nonwoven fabric formed from non-shrunk fibers.

Furthermore, the latent

crimped fibers

2f, 3f provided in the skin side layer 2 and non-skin side layer 3, respectively, are not likely to absorb liquid into the fibers themselves. For example, fibers such as pulp fibers absorb liquid (excrement) and become thicker, but the latent

crimped fibers

2f, 3f of the skin side layer 2 and non-skin side layer 3 are not likely to absorb liquid into the inside of the fibers even when they come into contact with liquid. Therefore, in the skin side layer 2 and non-skin side layer 3, even when the napkin 1 absorbs excrement while being worn, the latent

crimped fibers

2f, 3f of the skin side layer 2 and non-skin side layer 3 are not likely to become thicker themselves. Because the fibers themselves are not likely to become thicker, the size of the voids formed by the

fibers

2f, 3f are not likely to become smaller, and the voids are not likely to be crushed. For this reason, the skin side layer 2 and the non-skin side layer 3 can retain liquid (excrement) in the voids formed by the

fibers

2f and 3f, and therefore the skin side layer 2 and the non-skin side layer 3 are layers that are permeable to liquid and can absorb and retain liquid. In addition, the skin side layer 2 and the non-skin side layer 3 are nonwoven fabric sheets formed by the

fibers

2f and 3f, respectively, and have excellent breathability due to the voids formed by the

fibers

2f and 3f, and can reduce stuffiness and rough skin caused to the wearer when worn, improving comfort when worn.

As described above, the latent crimp fiber 2f in the skin side layer 2 is a latent crimp fiber that is a combination of PET and modified PET, and fibers of the same thickness are used throughout the entire area. In this embodiment, the thickness of the latent crimp fiber 2fa is 2.2 dtex. The average narrowness of the gaps in the skin side layer 2 is 104 μm. The proportion of gaps in the skin side layer 2 (the proportion of the area of the skin side layer 2 where fiber 2f is not provided) is 94%. The basis weight of the skin side layer 2 is approximately 170 gsm. It is preferable to use hydrophobic fibers on the skin side and hydrophilic fibers on the non-skin side in the skin side layer 2.

The latent crimp fibers 3f in the non-skin side layer 3 are all latent crimp fibers that are a combination of PET and modified PET, and fibers of the same thickness are used throughout the thickness direction. The thickness of the latent crimp fibers 3f in the non-skin side layer 3 in this embodiment is 2.2 dtex. The basis weight of the non-skin side layer 3 is approximately 120 gsm. It is preferable that the basis weight of the fibers 3f in the non-skin side layer 3 is 80 gsm or more and 200 gsm or less.

The non-skin side layer 3 has linear high density parts DH where the density of the fibers 3f is higher than the surrounding area (low density parts DL), and low density parts DL where the density of the fibers 3f is lower than the high density parts DH. The high density parts DH are thinner than the surrounding area (low density parts DL) and the fibers are not fused to each other.

The back sheet 4 is a liquid-impermeable sheet (outer layer) that is disposed on the non-skin side of the non-skin side layer 3. An example of a liquid-impermeable sheet is a polyethylene (PE) resin film. The side sheet 5 is a sheet that extends outward from both sides in the width direction of the skin side of the skin side layer 2. An example of the side sheet 5 is a hydrophobic air-through nonwoven fabric or a hydrophobic spunbond nonwoven fabric.

The napkin 1 also has a pair of wing portions 1w extending outward in the width direction at approximately the center in the longitudinal direction. The wing portions 1w are formed by a side sheet 5 and a back sheet 4. Note that the napkin 1 does not necessarily have to have wing portions 1w. If the napkin 1 does not have wing portions 1w, it may or may not have a side sheet 5.

The napkin 1 also has a compressed portion 20 where the skin side layer 2 and the non-skin side layer 3 are recessed in the thickness direction. The compressed portion 20 can fix the positions of the skin side layer 2 and the non-skin side layer 3 and improve the liquid diffusion properties of the napkin 1.

In the compressed portion 20, the thickness of the napkin 1 is thinner than the surrounding area, and the fiber density of the napkin 1 (skin side layer 2 and non-skin side layer 3) is higher. These comparisons may be made by known methods. Examples of the comparison of the thickness of the napkin 1 include a visual comparison method, and a method in which a dial thickness gauge ID-C1012C manufactured by Mitutoyo Corporation or an equivalent is used to obtain and compare values measured by applying a pressure of, for example, 3.0 gf/ ^cm2 to a target area. Examples of the comparison of the density of the napkin 1 include a comparison method based on an image of a cross section of the napkin 1 cut in the thickness direction, enlarged by an electron microscope or the like. The shape of the compressed portion 20 is not limited to that shown in FIG. 1. For example, a plurality of dot-like compressed portions may be arranged discretely.

<<<About the Absorbing Layer 10>>>
As described above, the absorbent layer 10 is an absorbent body used in the napkin 1 having a predetermined thickness and having a function of absorbing and retaining liquid. That is, the skin side layer 2 is capable of absorbing liquid and retaining liquid. The non-skin side layer 3 is capable of absorbing liquid and retaining liquid. In the napkin 1, the skin side layer 2 and the non-skin side layer 3 are used as an absorbent body in a state of being overlapped in the thickness direction. That is, the napkin 1 is composed of two nonwoven fabric

sheets having fibers

2f, 3f including latent crimp fibers. The absorbent layer 10 has voids formed by a plurality of

fibers

2f, 3f. Specifically, the skin side layer 2 has a plurality of fibers 2f having latent crimp fibers and has voids formed by the fibers 2f. The non-skin side layer 3 has a plurality of fibers 3f having latent crimp fibers and has voids formed by the fibers 3f. In this absorbent layer 10, the weight of the potentially crimped fibers divided by the weight of the plurality of

fibers

2f, 3f is 70% or more.

The absorbent layer 10 of the napkin 1 is constructed by overlapping a skin-side layer 2 and a non-skin-side layer 3, each of which has an absorption function. The skin-side layer 2 and the non-skin-side layer 3 may be fixed with an adhesive such as a hot melt adhesive, or no adhesive may be provided. In particular, by not providing adhesive between the skin-side layer 2 and the non-skin-side layer 3 in the center of the width direction when looking at the napkin 1 in the thickness direction, it is possible to reduce the risk that the adhesive will interfere with the absorption of excrement when the napkin 1 is worn.

The skin-side layer 2 is a nonwoven fabric sheet with a thickness of H2 and is composed of multiple fibers 2f. The non-skin-side layer 3 is a nonwoven fabric sheet with a thickness of H3 and is composed of multiple fibers 3f. In other words, the absorbent layer 10 is composed of two nonwoven fabrics with a thickness of H10 (H2+H3). In each layer, the gaps formed by the

multiple fibers

2f and 3f can absorb and hold excrement, and the gaps improve breathability. By improving the breathability of the absorbent layer 10, discomfort such as stuffiness when the napkin 1 is worn by the wearer can be reduced. In addition, in the absorbent layer 10, when the value obtained by dividing the weight of the latent crimped fiber by the weight of the

multiple fibers

2f and 3f is 70% or more, the nonwoven fabric sheet in the absorbent layer 10 is more likely to be strong and flexible due to the crimped fibers than when the value obtained by dividing the weight of the latent crimped fiber by the weight of the

multiple fibers

2f and 3f is less than 70%. This reduces twisting and deformation of the absorbent layer 10. A napkin 1 using this absorbent layer 10 reduces the leakage of excrement caused by twisting and deformation of the absorbent layer 10, and reduces the sense of incongruity and discomfort felt by the wearer due to twisting and deformation of the absorbent layer 10, improving comfort when worn.

The absorbent layer 10 of this embodiment is composed of a skin-side layer 2 of fiber 2f (100% latent crimp fiber) consisting only of latent crimp fiber, and a non-skin-side layer 3 of fiber 3f (100% latent crimp fiber) consisting only of latent crimp fiber, so the weight of the latent crimp fiber divided by the weight of the

multiple fibers

2f and 3 is 100%.

The

fibers

2f and 3f in the absorbent layer 10 do not necessarily have to be only latent crimp fibers (100% latent crimp fibers). Either one or both of the

fibers

2f and 3f may contain fibers other than latent crimp fibers (for example, liquid-absorbent fibers such as pulp fibers). Even in such a case, it is sufficient that the weight of the latent crimp fibers in the entire absorbent layer 10 divided by the weight of the

multiple fibers

2f and 3f is 70% or more. Furthermore, the absorbent layer 10 may contain not only the

fibers

2f and 3f but also a superabsorbent polymer (SAP) or the like.

The absorbent layer 10 preferably has an airflow resistance of 0.32 kpa·s/m or less. By making the airflow resistance of the absorbent layer 10 of the napkin 1 0.32 kpa·s/m or less, the breathability of the napkin 1 can be improved compared to when the airflow resistance is greater than 0.32 kpa·s/m, and discomfort such as stuffiness felt by the wearer of the napkin 1 can be reduced.

The airflow resistance of the absorbent layer 10 can be measured by a known method. For example, the absorbent layer 10 is cut into a circular sample of a given size (e.g., 70 mm diameter x 70 mm diameter). Then, using a Kato Tech Co., Ltd. air permeability tester (KES-F8) or an equivalent air permeability tester, the standard air flow rate is set to 2 cm/s and the air permeability of the sample is measured. This measurement is performed multiple times (e.g., 5 times), and the average value can be used as the air permeability of the absorbent layer 10.

Furthermore, if the fibers 2f of the skin side layer 2 or the fibers 3f of the non-skin side layer 3 are fused, the fused portions will have collapsed voids, which may reduce the absorption function, or the fusion of the

fibers

2f, 3f may cause the skin side layer 2 or the non-skin side layer 3 to harden. For this reason, it is preferable that the

multiple fibers

2f, 3f in the absorbent layer 10 are not fused to each other. This reduces the risk that the absorption and diffusion of excrement will be hindered in the absorbent layer 10, reducing the absorption function of the absorbent layer 10. It also reduces the risk that the fusion will cause the absorbent layer 10 to harden.

Figure 6 is a schematic diagram showing a cross section taken along the line B-B in Figure 4. In the thickness direction of the absorbent layer 10, the side that contacts the wearer's skin (the side that receives liquid) is the skin side, and the side opposite the skin side is the non-skin side (non-absorbent surface side). The absorbent layer 10 is divided into thirds in the thickness direction, with the area closest to the skin being the skin side area Qu, the area closest to the skin being the non-skin side area Qd, and the area between the skin side area Qu and the non-skin side area Qd being the intermediate area Qm.

In a narrowness evaluation test for quantitatively evaluating the narrowness of the gaps formed by the

fibers

2f and 3f, the average narrowness of the non-skin side region Qd is narrower than the average narrowness of the skin side region Qu in the narrowness test. The narrowness evaluation test will be described later. Therefore, the non-skin side region Qd is more likely to draw in liquid (excrement) by capillary action than the skin side region Qu.

Generally, absorbent cores using liquid-absorbent fibers such as pulp fibers are widely used in absorbent articles. Although this absorbent core has voids formed by the liquid-absorbent fibers, when the absorbent article absorbs excrement while being worn, the liquid-absorbent fibers themselves may absorb the liquid and become thicker, crushing the voids. Furthermore, if the absorbed excrement remains on the skin side in the thickness direction of the absorbent article or spreads on the skin side, the area over which the excrement spreads on the skin side of the absorbent article may become large, giving the impression that the excrement is not absorbed within the absorbent article or that the excrement that should have been absorbed by the absorbent article is in contact with the wearer's skin.

In contrast, since the average narrowness of the non-skin side region Qd in the narrowness evaluation test is narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test, the excrement received on the skin side of the skin side region Qu of the absorbent layer 10 in the worn state is more easily drawn toward the non-skin side region Qd by capillary action. Also, the excrement drawn into the non-skin side region Qd is more easily diffused over a wide area within the non-skin side region Qd. This reduces the amount of excrement absorbed from the skin side of the skin side region Qu remaining on the skin side of the skin side region Qu or within the skin side region Qu in the worn state, thereby reducing the discomfort caused by excrement continuing to come into contact with the wearer's skin and the risk of skin irritation. Also, even if a large amount of excrement is discharged at once, it is easier to promote the diffusion of excrement from the skin side region Qu toward the non-skin side region Qd, thereby reducing the risk of excrement leaking from the napkin 1 along the surface of the skin side region Qu. In particular, when the absorbent layer 10 contacts the wearer's skin, as in the case of the napkin 1, by making the average narrowness of the non-skin side region Qd in the narrowness evaluation test narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test, it becomes easier to diffuse excrement from the skin side to the non-skin side within the absorbent layer 10, thereby reducing the amount of excrement remaining on the skin side of the absorbent layer 10 and improving the comfort provided to the wearer when worn.

In addition, in the absorbent layer 10, by making the average narrowness of the non-skin side region Qd in the narrowness evaluation test narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test to promote diffusion from the skin side region Qu to the non-skin side region Qd, the diffusion area of the excrement in the skin side region Qu can be narrowed and the diffusion area of the excrement in the non-skin side region Qd can be made wider than when the average narrowness of the non-skin side region Qd in the narrowness evaluation test is wider than the average narrowness of the skin side region Qu in the narrowness evaluation test. This makes it easier to promote diffusion of excrement from the skin side to the non-skin side in the absorbent layer 10, and easier to promote diffusion of excrement in the non-skin side part of the absorbent layer 10 than in the skin side part, so that as shown in Figure 7, it is easier to make the diffusion area B3 of excrement in the non-skin side layer 3 wider than the diffusion area B2 of excrement in the skin side layer 2. Figure 7 is a diagram illustrating the napkin 1 30 minutes after horse blood has been dripped. Figure 7 is a diagram illustrating the state of the napkin 1 after 30 minutes have passed since 6 mm of horse blood was dropped onto the center of the length and width of the napkin 1. In this way, the area of the excrement diffusion area B3 in the non-skin side layer 3 is larger than the area of the excrement diffusion area B2 in the skin side layer 2, which makes it easier for the user to get the impression that the napkin 1 has excellent absorbency.

Furthermore, the

fibers

2f, 3f themselves, which contain latent shrinkage fibers, provided in the absorbent layer 10 of the napkin 1, have the property of being less likely to absorb liquid (excrement) than liquid-absorbent fibers such as pulp fibers. Therefore, by providing the

fibers

2f, 3f with latent shrinkage fibers in the absorbent layer 10, the

fibers

2f, 3f themselves are less likely to thicken even when excrement is absorbed while the napkin is being worn. In other words, by providing the absorbent layer 10 with latent shrinkage fibers, it becomes easier to maintain the gaps formed by the

fibers

2f, 3f.

As described above, in the napkin 1 of this embodiment, the nonwoven fabric sheets of the skin side layer 2 and the non-skin side layer 3 are formed by the spunlace method, and by applying a water flow from the skin side to the non-skin side, the

fibers

2f and 3f are easily pushed from the skin side to the non-skin side, so that the average narrowness of the non-skin side region Qd in the narrowness evaluation test is narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test. In addition, when the skin side layer 2 and the non-skin side layer 3 constituting the absorbent layer 10 are compared, the average narrowness of the non-skin side layer 3 in the narrowness evaluation test is narrower than the average narrowness of the skin side layer 2 in the narrowness evaluation test. This difference in the average narrowness of each layer is set by, for example, the amount and basis weight of the

fibers

2f and 3f used in each layer, the degree of entanglement of the

fibers

2f and 3f by the spunlace method, etc.

Note that the method of making the average narrowness of the non-skin side region Qd in the narrowness evaluation test narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test is not limited to this. For example, the thickness (fiber diameter) of the fibers in the non-skin side region Qd may be made thinner than the thickness (fiber diameter) of the fibers in the skin side region Qu. In addition, the average narrowness of the non-skin side region Qd in the narrowness evaluation test may be made narrower than the average narrowness of the skin side region Qu in the narrowness evaluation test by using latent shrinkage fibers that have a stronger shrinkage property than the fibers used in the skin side region Qu for the fibers used in the non-skin side region Qd.

In addition, it is preferable that the void ratio of the non-skin side region Qd in a void ratio evaluation test for quantitatively evaluating the void ratio in a specified region (measurement region Y) is smaller than the void ratio of the skin side region Qu in the void ratio evaluation test. The void ratio evaluation test will be described later. This makes it easier for the napkin 1 (absorbent layer 10) to draw excrement from the skin side region Qu to the non-skin side region Qd, which has a smaller void ratio, by capillary action when the napkin 1 (absorbent layer 10) absorbs excrement, and makes it easier to promote the diffusion of excrement within the non-skin side region Qd. In addition, it makes it easier to reduce the amount of excrement remaining in the skin side region Qu when the napkin 1 is worn, thereby reducing the discomfort caused by excrement coming into contact with the wearer's skin.

In the napkin 1 of this embodiment, as described above, the nonwoven fabric sheets of the skin side layer 2 and the non-skin side layer 3 are formed by the spunlace method, and by applying a water flow from the skin side to the non-skin side, the

fibers

2f, 3f are pushed from the skin side to the non-skin side, so that the void ratio of the non-skin side region Qd in the void ratio evaluation test is smaller than the void ratio of the skin side region Qu in the void ratio evaluation test. Note that the method of making the void ratio of the non-skin side region Qd in the void ratio evaluation test smaller than the void ratio of the skin side region Qu in the void ratio evaluation test is not limited to this. For example, the fiber thickness (fiber diameter) of the non-skin side region Qd may be made thinner than the fiber thickness (fiber diameter) of the skin side region Ru. In addition, by using latent crimp fibers that have a stronger tendency to crimp than the fibers used in the skin side region Ru as the fibers used in the non-skin side region Rd, the proportion of voids in the non-skin side region Rd in the void ratio evaluation test may be made smaller than the proportion of voids in the skin side region Ru in the void ratio evaluation test.

<Narrowness evaluation test method and void ratio evaluation test method>
The narrowness evaluation test and the void ratio evaluation test can be performed in the following manner.
First, X-ray CT measurement is performed on the absorber layer 10. Non-destructive tomography (CT measurement) is performed under the following conditions using a high-resolution 3D X-ray microscope nano3DX manufactured by Rigaku Corporation.
X-ray source: Cu
Tube voltage-tube current: 40kV-30mA
Detector: sCMOS camera (lens: 1080)
Resolution: 2.51 μm/voxel

A measurement area (predetermined area) Y of the absorbent layer 10 is randomly extracted from the three-dimensional data obtained by photography, and the voids are analyzed. The measurement area Y for this analysis is a rectangular parallelepiped (or cube) whose length in the thickness direction is the thickness H10 of the absorbent layer 10, within any range in the surface direction of the absorbent layer 10.

In this embodiment, as shown in FIG. 8, when the measurement area Y is divided into three equal parts in the thickness direction, the lowest part is the first area Y1, the highest part is the third area Y3, and the part between the first area Y1 and the third area Y3 is the second area Y2. FIG. 8 is a diagram explaining the measurement area Y, in which the

fibers

2f and 3f are the colored (gray) parts, the voids are the colored (white) parts, and the lattice part indicates the range of the measurement area randomly extracted from the absorbent layer 10. The first area Y1 is the skin side area Qu of the absorbent layer 10 (a part of the skin side area Qu when viewed in the thickness direction), the second area Y2 is the middle area Qm of the absorbent layer 10 (a part of the middle area Qm when viewed in the thickness direction), and the third area Y3 is the non-skin side area Qd of the absorbent layer 10 (a part of the non-skin side area Qd when viewed in the thickness direction).

The cross-sectional image obtained by X-ray CT shows low-density (void) components that easily transmit X-rays in black, and high-density (fiber) components that easily absorb X-rays in white. From this image, the void ratio and average void narrowness of each region Y1 to Y3 are calculated.

The void ratio of each of the regions Y1 to Y3 can be calculated by obtaining the volume of the void in each of the regions Y1 to Y3 and the volume of the measurement region Y from a tomographic image obtained by X-ray CT. For example, the void ratio of the first region Y1 is as follows.
Void ratio of first region Y1=(volume of void in first region Y1)/(volume of first region Y1)
The volume of the first region Y1 is the sum of the volume of the fibers in the first region Y1 and the volume of the voids in the first region Y1.

The gap narrowness of each region Y1 to Y3 is calculated by applying the thickness of "A new method for the model-independent assessment of thickness in three-dimensional images" (T. HILDEBRANDO & P. RUEGSEGGER, Journal of Microscopy, Vol. 185, Pt1, January 1997, pp. 67-75) to the spatial portion, and the distribution of gap narrowness and the average gap narrowness are calculated based on the partial narrowness of the volume (gap). In other words, the "thickness" in the definition in the above-mentioned document corresponds to the "narrowness of the gap" in the skin-side layer 2 (each of the regions Y1 to Y3), and by identifying the narrowness in each part of the volume portion that corresponds to the gap in the tomographic image obtained by X-ray CT, the distribution of gap narrowness and the average gap narrowness can be obtained.

A quantitative evaluation method for the narrowness of a gap (for example, gap Z) in each of the analyzed regions Y1 to Y3 will be described below. Figure 9 is a diagram for explaining the outline of the narrowness evaluation method for gap Z. For example, as shown in Figure 9, at any point P1 to P4 inside gap Z, the largest sphere in the region including each point is assumed, and the diameters D1 to D4 of each sphere are obtained. Note that the process of obtaining the diameters D1 to D4 of the spheres at four points (points P1 to P4) was described using Figure 9, but in an actual quantitative evaluation of the narrowness of a gap, a process of obtaining the diameters D of the spheres at multiple points P inside gap Z is performed. This process is performed at all points in each of the regions Y1 to Y3, the distribution of the obtained diameters is calculated, and the average value is obtained, so that the average narrowness of the gaps in each of the regions Y1 to Y3 can be quantitatively evaluated.

Furthermore, it is preferable that the hydrophilicity of the skin side region Qu is lower than that of the non-skin side region Qd. As shown in FIG. 5A, the skin side layer 2 of this embodiment includes an upper layer 2A formed mostly of hydrophobic fibers 2fa and a lower layer 2B formed mostly of hydrophilic fibers 2fb, and the non-skin side layer 3 is formed of hydrophilic fibers 3f as shown in FIG. 5B. In other words, in the absorbent layer 10 in which the skin side layer 2 and the non-skin side layer 3 are superimposed, the hydrophilicity of the non-skin side region Qd (fibers 2fb, 3f of the lower layer 2B and non-skin side layer 3 located on the non-skin side of the upper layer 2A) is higher than that of the skin side region Qu (fibers 2fa in the upper layer 2A) which is closest to the skin. This reduces the risk that excrement absorbed in the skin side region Qu will remain in the skin side region Qu when worn, and makes it easier to draw it toward the non-skin side region Qd. Furthermore, excrement that reaches the non-skin side region Qd can be easily dispersed within the non-skin side region Qd, reducing the risk of excrement returning from the non-skin side region Qd to the skin side region Qu. This reduces the risk of excrement staying in the skin side region Qu and continuing to come into contact with the wearer's skin.

The hydrophilicity of each region is determined based on the contact angle with water. The contact angle between each region and water can be measured by the following method.
First, a rectangular shape in plan view with a length of 150 mm and a width of 70 mm is cut out from the region to be measured to obtain a measurement sample (if it is difficult to cut out, the maximum length and maximum width are not limited to the example values as long as they are within the range that can be measured). Then, a droplet of ion-exchanged water is attached to the surface to be measured for the contact angle of each measurement sample, the droplet is recorded, and the contact angle is measured based on the recorded image. More specifically, a microscope VHX-1000 manufactured by Keyence Corporation is used as the measurement device, and a medium-magnification zoom lens is attached to it in a state inclined at 90°. Each measurement sample is set on the measurement stage of the measurement device so that the surface to be measured faces upward and can be observed from the width direction of each measurement sample. Then, a droplet of 3 μL of ion-exchanged water is attached to the surface to be measured of each measurement sample set on the measurement stage, and an image of the droplet is recorded and taken into the measurement device. From the recorded images, 10 images in which both ends or one end of the droplet in the width direction are clear are selected, the contact angle of the droplet is measured for each of the 10 images, and the average of the contact angles is taken as the contact angle of the measurement target area (fiber layer). The measurement environment is 20°C/50% RH.

The smaller the contact angle with water measured by the above method, the higher the hydrophilicity (lower hydrophobicity), and the larger the contact angle, the lower the hydrophilicity (higher hydrophobicity). If the contact angle is less than 90 degrees, it is hydrophilic, and if it is 90 degrees or more, it is hydrophobic. In other words, in the skin-side layer 2, the contact angle with water on the skin-side region Ru side is larger than the contact angle with water on the non-skin-side region Rd.

In the present embodiment, the absorbent layer 10 has hydrophobic fibers 2fa provided on the side closest to the skin in the thickness direction (upper layer 2A of the skin-side layer 2), and hydrophilic fibers 2fb and 3f provided on the non-skin side of the upper layer 2A, making the hydrophilicity of the skin-side region Qu lower than that of the non-skin-side region Qd, but this is not limited to this. For example, the entire area of the nonwoven fabric sheet of the absorbent layer 10 (skin-side region Qu, middle region Qm, non-skin-side region Qd) may be formed of

fibers

2f and 3f with a constant hydrophilicity, and the skin-side region Qu of the absorbent layer 10 (two nonwoven fabric sheets) may be processed to apply a hydrophobic agent, and the non-skin-side region Qd may be processed to apply a hydrophilic agent.

Furthermore, it is preferable that the basis weight of the

fibers

2f, 3f of the absorbent layer 10 is 80 gsm or more and 350 gsm or less. By making the basis weight of the

fibers

2f, 3f of the absorbent layer 10 80 gsm or more, the texture is improved and the absorbency and liquid retention of excrement are ensured, making it easier to absorb excrement, compared to when the basis weight of the

fibers

2f, 3f of the absorbent layer 10 is less than 80 gsm. Furthermore, by making the basis weight of the

fibers

2f, 3f of the absorbent layer 10 350 gsm or less, it is possible to reduce discomfort during wearing caused by the absorbent layer 10 being excessively thick or excessively stiff, compared to when the basis weight of the

fibers

2f, 3f of the absorbent layer 10 is more than 350 gsm.

The absorbent layer 10 has a desired absorption function. The absorption function of the absorbent layer 10 can be measured by the following absorption test.
<Method of measuring absorption function>
(1) First, the absorbent layer 10 (the skin side layer 2 and the non-skin side layer 3) is removed from the napkin 1.
(2) Next, when viewed in the thickness direction of the napkin 1, the center in the longitudinal direction and the center in the width direction of the absorbent layer 10 are defined as a predetermined region, and this predetermined region is cut out as a sample. In the napkin 1 of this embodiment, the sample has a size of 70 mm x 70 mm.
(3) Then, the weight of this sample, i.e., pre-absorption weight a, is measured using a balance with a sensitivity of 0.01 g. Pre-absorption weight a is the weight of the sample before it absorbs distilled water.
(4) Next, one end of the sample is clamped with a clip so that the tip of the clip and the sample are perpendicular to the vertical direction.
The sample, together with the clip, is immersed in a water tank containing distilled water (or deionized water) at 23±1° C., with the skin side of the absorbent layer 10 facing up. The sample is gently pressed toward the water, and the state in which the entire sample is completely immersed in the distilled water is maintained for 60 seconds.
(5) Thereafter, the clip is pulled up, the sample is pulled out of the distilled water, and the sample is clamped with the clip while being completely removed from the water surface of the tank, and the sample is left hanging from the clip for 90 seconds.
(6) Then, the mass of the sample excluding the clip is weighed to obtain the post-absorption weight A, which is the weight of the sample after absorption.
(7) The absorbed weight b is calculated by subtracting the weight a before absorption from the weight A after absorption.
(Absorption weight b) = (Weight after absorption A) - (Weight before absorption a)
It is preferable that the value obtained by dividing the obtained absorption weight b by the weight a before absorption is 5 or more.
Absorption weight b÷weight before absorption a≧5
The above steps (1) to (7) are carried out for each of the five samples, and the average value of the results for the five samples is regarded as the measurement result.

Figure 10 shows the measurement results of the absorption test of the absorbent layer 10. Numbers 1 to 3 in Figure 10 each indicate the average results of five samples. As shown in Figure 10, in the absorbent layer 10 of the napkin 1 of this embodiment, the values obtained by dividing the weight of absorbed distilled water (absorption weight b) by the weight of a specified area before absorbing distilled water are each greater than 7. In other words, the value obtained by dividing the absorption weight b by the pre-absorption weight a is clearly 5 or greater. Therefore, the absorbent layer 10 of the napkin 1 has a sufficient absorption capacity to absorb excrement, and the risk of excrement leaking from the napkin 1 can be reduced.

The greater the value obtained by dividing the absorption weight b by the pre-absorption weight a, the more distilled water the absorbent layer 10 can absorb, and therefore the more excrement it can absorb. By making the value obtained by dividing the absorption weight b by the pre-absorption weight a 5 or more, the napkin 1 equipped with the absorbent layer 10 can ensure sufficient liquid absorption function compared to when the value obtained by dividing the absorption weight b by the pre-absorption weight a is less than 5. In addition, it becomes possible to retain the absorbed liquid within the absorbent layer 10. In this way, the absorbent layer 10 has an absorption function that is sufficient to absorb excrement, and it becomes possible to diffuse and retain the absorbed excrement within the absorbent layer 10.

The bending stiffness B of the absorbent layer 10 in the napkin 1 at the longitudinal center and the width center is preferably 1.2 gf·cm ² /cm or less according to the KES method. In this embodiment, the longitudinal center of the absorbent layer 10 is the crotch region, and the longitudinal center and the width center are also the excretory opening contact region when worn. Generally, the greater the value of the bending stiffness B, the greater the bending stiffness. By setting the bending stiffness B at the longitudinal center and the width center of the absorbent layer 10 at 1.2 gf·cm ² /cm or less according to the KES method, the absorbent layer 10 can be made more flexible than when the bending stiffness B at the longitudinal center and the width center of the absorbent layer 10 is greater than 1.2 gf·cm ² /cm, and the napkin 1 using the absorbent layer 10 can be made more flexible. Therefore, when worn, the napkin 1 can easily conform to the shape and movements of the wearer's body, reducing the sense of discomfort felt by the wearer and improving comfort when worn.

<Method for measuring bending rigidity B>
The bending stiffness B (gf·cm ² /cm) at the center of the length and width of the absorbent layer 10 can be measured by a known method. For example, the value of bending stiffness B (gf·cm ² /cm) can be measured using a large bending tester KES-FB2-L manufactured by Kato Tech Co., Ltd. First, the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) is removed from the napkin 1, and a portion of 50 mm×50 mm in the center of the length and width of the absorbent layer 10 is cut out as a sample. This sample is fixed between the chucks of the tester so that it can be measured by bending it along the length of the absorbent layer 10. The measurement is performed by bending the absorbent layer 10 to the front side to a maximum curvature of +0.5 cm ⁻¹ , then bending it to the back side to a maximum curvature of −0.5 cm ⁻¹ , and then returning it to its original state. The bending stiffness value B (gf·cm ² /cm) is calculated from the average value of the bending moment gradient for a curvature of 0.1 to 0.3 when bent to the front side and the gradient for a curvature of -0.1 to -0.3 when bent to the back side.

FIG. 11A shows the results of measuring the bending properties using the KES method. FIG. 11A shows the results of measuring the bending properties using the KES method for the absorbent layer 10 of the napkin 1 of this embodiment and the absorbent body (absorbent layer) of the comparative product X, which is an existing sanitary napkin.

Comparative Product X is a sanitary napkin with a conventionally well-known configuration, which is comprised of a top sheet, absorbent, and back sheet in that order from the skin side. The top sheet of Comparative Product X is a sheet member that has excellent liquid permeability but has difficulty absorbing or retaining liquid. The absorbent of Comparative Product X is a polymeric foam structure that can absorb and retain liquid. The back sheet of Comparative Product X is a liquid-impermeable sheet member. Since the top sheet of Comparative Product X allows liquid to pass through but has difficulty absorbing or retaining liquid, it was determined that the absorbent layer of Comparative Product X is only the absorbent, and the absorbent was removed from Comparative Product X and the bending properties were measured using the above-mentioned KES method at the longitudinal center and width center of Comparative Product X, in the same manner as with Napkin 1.

11A, the bending stiffness B (gf·cm ² /cm) at the longitudinal center and width center of the absorbent layer 10 of the napkin 1 of this embodiment is 0.1008 to 1.1017 gf·cm ² /cm, which is less than 1.2 gf·cm ² /cm. In contrast, the bending stiffness B (gf·cm ² /cm) at the longitudinal center and width center of the absorbent body of the comparative product X is 0.5493 to 6.1168 gf·cm ² /cm. Furthermore, the average value of the measurement results of the bending stiffness B of the absorbent layer 10 of the napkin 1 (0.5390 gf·cm ² /cm) is smaller than the average value of the measurement results of the bending stiffness B of the absorbent body of the comparative product X (2.5294 gf·cm ² /cm). From these results, it can be seen that the absorbent layer 10 of the napkin 1 is softer than the absorbent body of the comparative product X, and therefore the napkin 1 can be made softer than the comparative product X. As a result, the napkin 1 can more easily conform to the shape and movements of the wearer's body when worn than the comparative product X, reducing the discomfort felt by the wearer and improving comfort when worn.

The bending hysteresis 2HB measured by the KES method at the longitudinal center and width center of the absorbent layer 10 in the napkin 1 is preferably 0.93 gf·cm ² /cm or less. The 2HB value indicates bending recovery, and the larger the bending hysteresis 2HB value, the worse the recovery. By setting the bending hysteresis 2HB measured by the KES method at the longitudinal center and width center of the absorbent layer 10 to 0.93 gf·cm ² /cm or less, the absorbent layer 10 deformed by an external force or ^the like when worn can be easily restored to its original shape, compared to when the bending hysteresis 2HB measured by the KES method at the longitudinal center and width center of the absorbent layer 10 is greater than 0.93 gf·cm 2 /cm, and the discomfort and unease caused to the wearer by the deformation of the absorbent layer 10 can be reduced.

<Method of measuring bending hysteresis 2HB>
The bending hysteresis 2HB (bending recovery) can be measured by a known method, for example, using an automated bending tester (KES-FB2-L) manufactured by Kato Tech Co., Ltd.
First, the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) is removed from the napkin 1, and a portion measuring 50 mm×50 mm is cut out as a sample from the longitudinal center and width center of the absorbent layer 10.
Next, both ends of the sample in the longitudinal direction are held by chucks. The sample is then bent in both positive and negative directions at a curvature change rate of 0.1 cm-1/min, with a curvature of 0.5 cm-1 on the positive side and 0.5 cm-1 on the negative side, to obtain a hysteresis curve of the bending moment required for bending in each direction. The amount of hysteresis of the bending moment when the curvature is 0.1 cm-1 is defined as the bending hysteresis 2HB.

Similar to the bending rigidity B, Figure 11A shows the measurement results of bending hysteresis 2HB (gf· ^cm2 /cm) by the KES method at the longitudinal center and width center of the absorbent layer 10 of the napkin 1 of this embodiment, and the measurement results of bending hysteresis 2HB (gf· ^cm2 /cm) by the KES method at the longitudinal center and width center of the absorbent body of the comparative product X.

11A, the bending hysteresis 2HB (gf·cm ² /cm) at the longitudinal center and width center of the absorbent layer 10 of the napkin 1 of this embodiment is 0.8204-0.9253 gf·cm ² /cm, which is less than 0.93 gf·cm ² /cm. In contrast, the bending hysteresis 2HB (gf·cm ² /cm) at the longitudinal center and width center of the absorbent body of the comparative product X is 4.0183-4.8341 gf·cm ² /cm, which is clearly greater than 0.93 gf·cm ² /cm. From this result, the napkin 1 is easier to restore the absorbent layer 10 to its original shape when worn, even if the absorbent layer 10 is deformed by external forces such as the wearer's body shape or the wearer's movement, and can reduce the discomfort and strangeness caused to the wearer by the deformation of the absorbent layer 10, compared to the comparative product.

It is preferable that the linearity LC (compression hardness) of the compression characteristics of the absorbent layer 10 of the napkin 1 at the longitudinal center and the width center is 0.6 or more, as determined by the KES method. The larger the value of the linearity LC (compression hardness) of the compression characteristics, the stiffer the compression is. By making the linearity LC (compression hardness) of the compression characteristics 0.6 or more, the deformation of the absorbent layer 10 can be reduced more than when the linearity LC (compression hardness) of the compression characteristics is less than 0.6, and therefore the discomfort felt by the wearer due to the deformation of the absorbent layer 10 when worn can be reduced. In addition, the risk of excrement leaking from the absorbent layer 10 due to the deformation of the absorbent layer 10 can be reduced.

In addition, the compression resilience RC (compression recovery) of the absorbent layer 10 in the napkin 1 at the longitudinal center and width center is preferably 38.0% or more. The closer the compression resilience RC (compression recovery) value is to 100%, the higher the recovery. Even if the absorbent layer 10 is deformed by the application of force to the napkin 1 when worn, by setting the compression resilience RC (compression recovery) at the longitudinal center and width center of the absorbent layer 10 at 38.0% or more, the shape of the absorbent layer 10 can be restored more easily than when the compression resilience RC (compression recovery) at the longitudinal center and width center of the absorbent layer 10 at the KES method is less than 38.0%, so that the discomfort caused by the deformation of the absorbent layer 10 when worn by the wearer can be reduced.

<Method of measuring linearity LC and compression resilience RC of compression characteristics>
The linearity LC (compressive hardness) and compressive resilience RC (compressive recovery) of the compression characteristics can be measured by a known method, for example, using an automated compression tester KES-FB3 AUTO-A manufactured by Kato Tech Co., Ltd.
First, the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) is removed from the napkin 1, and a portion measuring 50 mm×50 mm is cut out as a sample from the longitudinal center and width center of the absorbent layer 10.
Each sample is compressed in a predetermined area between steel plates having a circular, flat terminal with an area of ²⁰⁰ mm2 at a compression speed of 50 sec/mm and a maximum compression load of 50 gf/ ^cm2 to measure the compression characteristics of the sample.
The compression characteristics are also measured during the recovery process at the same speed, and the linearity LC of the compression characteristic curve obtained from the measurement and the compression recovery rate RC [%] are calculated.

FIG. 11B shows the results of measuring the compression characteristics using the KES method. FIG. 11B shows the results of measuring the compression characteristics using the KES method for the absorbent layer 10 of the napkin 1 of this embodiment and the absorbent body (absorbent layer) of comparative product X, which is an existing sanitary napkin. Note that comparative product X is the same product whose bending characteristics were measured using the KES method described above.

11B, the linearity LC of the compression characteristics at the longitudinal center and width center of the absorbent layer 10 of the napkin 1 of this embodiment is 0.609 to 0.653, which is 0.6 or more. In contrast, the linearity LC of the compression characteristics at the longitudinal center and width center of the absorbent body of the comparative product X is 0.365 to 0.757. In addition, the average value of the linearity LC of the compression characteristics at the longitudinal center and width center of the absorbent layer 10 of the napkin 1 of this embodiment is 0.632, while the linearity LC of the compression characteristics at the longitudinal center and width center of the absorbent body of the comparative product X is 0.575. From this result, the absorbent layer 10 of the napkin 1 can reduce deformation more than the absorbent body of the comparative product X, and can reduce the discomfort caused by the deformation of the absorbent layer 10 that is given to the wearer when worn. In addition, the absorbent layer 10 of Napkin 1 can reduce leakage of excrement caused by deformation of the absorbent layer 10 more than the absorbent body of Comparative Product X.

As for the compression resilience RC, as shown in FIG. 11B, the compression resilience RC at the longitudinal and widthwise central portions of the absorbent layer 10 of the napkin 1 of this embodiment is 38.80-40.18%, which is clearly greater than 38%. In contrast, the compression resilience RC at the longitudinal and widthwise central portions of the absorbent body of the comparative product X is 41.50-59.216%. In other words, the absorbent layer 10 of the napkin 1 of this embodiment has the same compression resilience RC characteristics as the comparative product X, which makes it easier for the absorbent layer 10 to return to its original shape, reduces discomfort caused by deformation of the absorbent layer 10 when worn, and improves breathability, thereby improving comfort when worn.

Furthermore, in an elongation test for measuring the magnitude of force required to elongate the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) to a predetermined length, it is preferable that the value obtained by dividing the value of the force magnitude in the tenth measurement of the elongation test of the absorbent layer 10 by the value of the force magnitude in the first measurement of the elongation test of the absorbent layer 10 is 50% or more. By dividing the value of the force magnitude in the tenth measurement of the elongation test by the value of the force magnitude in the first measurement being 50% or more, damage to the absorbent layer 10 can be reduced even when the absorbent layer 10 is worn, compared to when the value of the force magnitude in the tenth measurement of the elongation test divided by the value of the force magnitude in the first measurement is less than 50%, and a predetermined stress can be maintained even when the absorbent layer 10 is repeatedly stretched by applying force to it, so that the napkin 1 equipped with the absorbent layer 10 can easily follow the shape and movement of the wearer's body. In other words, a napkin 1 equipped with such an absorbent layer 10 can be made to be a napkin 1 in which the absorbent layer 10 is less likely to break when external force is applied to the absorbent layer 10 while it is being worn, and in which the absorbent layer 10 easily adapts to the shape and movements of the wearer's body.

<Measurement method for elongation test>
The elongation test can be performed by a cycle test using an autograph tensile tester, for example, model AG-1KNI, manufactured by Shimadzu Corporation. The specific measurement method is as follows.
First, the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) which is the measurement target area is taken out from the napkin 1 to be measured, and a sample is prepared. The cut-out sample is fixed to the chuck of the tester with the chuck distance set to 100 mm. Next, the sample is stretched in the longitudinal direction at a speed of 100 mm/min to 130% of the chuck distance of 100 mm, i.e., to a chuck distance of 130 mm, and then returned to the position of the chuck distance of 100 mm at a speed of 100 mm/min. The maximum value of the force magnitude (N) at this time is taken as the measurement result value of the first stretching test (the force magnitude value from the first measurement).
Next, the sample with the chuck distance of 100 mm is stretched in the longitudinal direction at a speed of 100 mm/min to 130% of the chuck distance of 100 mm, that is, to a chuck distance of 130 mm, and then returned to the chuck distance of 100 mm at a speed of 100 mm/min. The maximum value of the force magnitude (N) at this time is taken as the measurement result value of the second extension test (the force magnitude value from the second measurement). The extension test is performed in the same manner, and the measurement result values of the third to tenth tests are obtained.
Then, a value is calculated by dividing the tenth measurement result value (the value of the magnitude of the force from the tenth measurement) by the first measurement result value (the value of the magnitude of the force from the first measurement).

Figure 12 shows the measurement results of an elongation test of the absorbent layer 10. Figure 12 shows the measurement results of an elongation test of the absorbent layer 10 of the napkin 1 of this embodiment and the absorbent body (absorbent layer) of comparative product X, which is an existing sanitary napkin. Note that comparative product X is the same product whose bending properties were measured using the KES method described above.

The measurement results (force magnitude) of the extension test of napkin 1 are shown in FIG. 12, and the measurement result (force magnitude) of the 10th extension test of the absorbent layer 10 of napkin 1 is 15.270 N. The force magnitude value from the 10th measurement of the extension test of napkin 1 (15.270 [N]) divided by the force magnitude value from the first measurement (20.967 [N]) is 15.270 [N] / 20.967 [N] = 0.7283, which is clearly more than 50%. In contrast, in comparison product X, the absorbent body broke in the second extension test, and no measurement result could be obtained from the 10th extension test. In other words, it was 0 N. Since the 10th measurement result of the absorbent layer 10 of napkin 1 is greater than 0 N, damage or breakage of the absorbent layer 10 can be reduced even when an external force is applied while the napkin is being worn. Therefore, the absorbent layer 10 of the napkin 1 of this embodiment is less likely to break or rupture when worn than the absorbent of the comparative product X. In addition, the force magnitude value (15.270 [N]) from the 10th measurement of the elongation test divided by the force magnitude value (20.967 [N]) from the first measurement is 15.270 [N] / 20.967 [N] = 0.7283, which is clearly 50% or more. This makes it easier for the absorbent layer 10 to adapt to the wearer's body and movements than when the force magnitude value from the 10th measurement of the elongation test divided by the force magnitude value from the first measurement is less than 50%, making it easier for the wearer to feel comfortable when wearing the napkin.

In the above embodiment, the fibers (latent shrink fibers) 2f, 3f constituting the absorbent layer 10 have the same thickness (2.2 dtex) throughout the entire area of each nonwoven fabric, but this is not limited to this. The thickness (fiber diameter) of the

fibers

2f, 3f in the absorbent layer 10 (skin side layer 2, non-skin side layer 3) can be selected arbitrarily. For example, when the skin side of the center in the thickness direction of the absorbent layer 10 is defined as the first region, and the non-skin side of the center in the thickness direction of the absorbent layer 10 is defined as the second region, the maximum fiber thickness of the first region may be greater than the maximum fiber thickness of the second region. In general nonwoven fabrics, the thicker the fibers are, the larger the gaps formed by the multiple fibers are likely to be. Therefore, by capillary action, it becomes easier to draw excrement into the second region, which has a smaller maximum fiber thickness than the first region, and it becomes easier to diffuse excrement in the second region, thereby reducing the risk of excrement remaining on the skin side of the first region. This reduces the risk of excrement coming into contact with the wearer's skin while the garment is being worn, improving comfort while it is being worn.

In the above embodiment, the skin side layer 2 and the non-skin side layer 3 that are overlapped while being in contact with each other are used as the absorbent layer 10, but this is not limited to this. Even if a highly liquid permeable sheet member that does not have the function of absorbing and retaining liquid is sandwiched between the skin side layer 2 and the non-skin side layer 3, the skin side layer 2 and the non-skin side layer 3 may form the absorbent layer 10. Furthermore, the number of nonwoven fabrics containing fibers containing latent crimped fibers that constitute the absorbent layer 10 is not limited to two (skin side layer 2 and non-skin side layer 3). The number of nonwoven fabrics containing fibers containing latent crimped fibers that constitute the absorbent layer 10 may be one (only the skin side layer 2 or only the non-skin side layer 3), or may be three or more. The configuration of the above embodiment can be applied even if the number of nonwoven fabrics containing fibers containing latent crimped fibers that constitute the absorbent layer 10 is one or three or more.

FIG. 13 is a diagram illustrating a napkin 100 that is a modified example of this embodiment. As with the napkin 100 shown in FIG. 13, the napkin 100 may be made up of only the skin side layer 2, which is the absorbent layer 10 (absorbent body), and the back sheet 4. Note that, unlike the napkin 100, it is not necessarily required to have a side sheet 5.

The skin-side layer 2 of the napkin 100 is a member that contacts the wearer's skin and is an absorbent member that can hold liquid (excrement) in the gaps formed by the fibers 2f. The back sheet 4 is a liquid-impermeable sheet, as described above.

The skin-side layer 2 (absorbent layer 10) of the napkin 100 is a layer that is capable of absorbing liquid and retaining liquid. Figure 14 is a diagram illustrating the skin-side layer 2 of the napkin 100. The skin-side layer 2 is a nonwoven fabric sheet formed of fibers 2f that are only latent crimp fibers (100% latent crimp fibers). The skin-side layer 2 has voids formed by the multiple fibers 2f. In this skin-side layer 2, the weight of the latent crimp fibers divided by the weight of the multiple fibers 2f is 70% or more.

In the skin-side layer 2, the gaps formed by the multiple fibers 2f can absorb and retain excrement, and the gaps formed by the fibers 2f improve breathability. By improving the breathability of the skin-side layer 2, it is possible to reduce discomfort such as stuffiness when the wearer of the napkin 1 is wearing the napkin. In addition, in the skin-side layer 2, when the weight of the latent crimped fiber divided by the weight of the multiple fibers 2f is 70% or more, the nonwoven fabric sheet in the skin-side layer 2 is more likely to be strong and flexible due to the crimped fiber than when the weight of the latent crimped fiber divided by the weight of the multiple fibers 2f is less than 70%. Therefore, it is possible to reduce twisting and deformation of the skin-side layer 2. The napkin 1 using this skin-side layer 2 as the absorbent layer 10 can reduce leakage of excrement due to twisting and deformation of the skin-side layer 2, and reduce the sense of incongruity and discomfort caused to the wearer due to twisting and deformation of the skin-side layer 2, thereby improving comfort when worn. Furthermore, when the number of components used is small (skin side layer 2 and back sheet 4), as in the case of napkin 100, production costs can be reduced. Furthermore, by reducing the number of components used, the rigidity of the components and adhesives used to bond the components can be reduced, and the rigidity of the napkin can be reduced and the napkin can be made softer, reducing the discomfort felt when worn and improving comfort when worn.

14, the skin side layer 2 is divided into three equal parts in the thickness direction, the region closest to the skin is the skin side region Ru, the region closest to the skin is the non-skin side region Rd, and the region between the skin side region Ru and the non-skin side region Rd is the intermediate region Rm, and when at least a part of the fibers 2f in the non-skin side region Rd is more hydrophilic than the fibers 2f in the skin side region Ru, a part of the fibers 2f in the non-skin side region Rd may be exposed on the skin side surface of the skin side layer 2. Specifically, as shown in FIG. 14, when the skin side layer 2 has hydrophilic fibers 2fb in the non-skin side region that are more hydrophilic than the fibers 2f in the skin side region Ru, the skin side layer 2 may have hydrophilic fibers 2fb exposed on the skin side surface. The hydrophilic fibers 2fb exposed on the skin side surface of the skin side layer 2 make it easier to draw excrement absorbed from the skin side toward the non-skin side region Rd. This makes it easier to promote the diffusion of excrement from the skin side to the non-skin side in the skin side layer 2, and also makes it easier to promote the diffusion of liquid in the non-skin side region Rd, reducing the risk of excrement remaining on the skin side (surface) of the skin side region Rd, reducing the discomfort caused by excrement continuing to come into contact with the wearer's skin, and improving comfort when worn.

In the process of forming this nonwoven fabric sheet, the hydrophobic fibers 2fa in the skin side region Ru and the hydrophilic fibers 2fb in the non-skin side region Rd are laminated together and then subjected to high-pressure water jet processing, such as water jetting, to entangle the fibers between the fiber layers and the fibers between the webs (step (d) of forming a nonwoven fabric by the spunlace method described above). At this time, the water flow that passes through the hydrophobic fibers 2fa and then the hydrophilic fibers 2fb is reflected by the conveyor belt and directed toward the skin side in the order of the hydrophilic fibers 2fb and the hydrophobic fibers 2fa, thereby pulling the hydrophilic fibers 2fb up toward the skin side region Ru. This provides the hydrophilic fibers 2fb exposed on the skin side surface of the skin side layer 2.

The method for providing the hydrophilic fibers 2fb exposed on the skin-facing surface of the skin-side layer 2 is not limited to this. Any well-known method can be used. For example, the fibers 2f may be intertwined with each other by the spunlace method, and then the hydrophilic fibers 2fb may be exposed on the skin-facing surface of the skin-side layer 2 by the needle punch method.

The napkin 100, in which the skin-side layer 2 is the absorbent body (absorbent layer 10) of the present invention, is an absorbent article consisting of the skin-side layer 2 and the back sheet 4, but is not limited to this. Even if the skin-side layer 2 is the absorbent layer 10, the absorbent article can be made by combining any members. For example, in the case of a napkin having the skin-side layer 2, the non-skin-side layer 3, and the back sheet 4, the non-skin-side layer 3 may be a member that does not have the function of absorbing and retaining liquid, and an additional sheet member that does not have the function of absorbing liquid may be arranged on the non-skin side of the back sheet 4. In addition, in the case of an absorbent article in which the skin-side layer 2 is the absorbent body (absorbent layer 10) of the present invention or in the case in which the skin-side layer 2 and the non-skin-side layer 3 are the absorbent body (absorbent layer 10) of the present invention, another sheet member (for example, a liquid-permeable top sheet) may be arranged on the skin side of the skin-side layer 2.

Similarly, the napkin (not shown) may be composed only of the non-skin side layer 3, which is the absorbent layer 10 (absorbent body), and the back sheet 4. Furthermore, when the napkin has the skin side layer 2, the non-skin side layer 3, and the back sheet 4, the skin side layer 2 may be a member that does not have the function of absorbing and retaining liquid.

Furthermore, the sanitary napkin may be a napkin (not shown) formed of an absorbent layer 10 consisting only of the skin side layer 2 (or non-skin side layer 3) without a back sheet 4. For example, the napkin may have a water-repellent finish applied to the non-skin side of the skin side layer 2 (non-skin side layer 3). By making the napkin formed only of the skin side layer 2 (or non-skin side layer 3), the number of components can be reduced. In this way, by reducing the number of components used, production costs can be reduced and the rigidity of the components and adhesives for bonding the components can be reduced, and the rigidity of the napkin can be reduced to make it softer, thereby reducing the discomfort felt when worn and improving comfort when worn.

===Other embodiments===
The above-described embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

1. Napkins (sanitary napkins, absorbent articles),
1w wing part,
2. Skin side layer (absorbent body),
2f latent crimp fiber (fiber),
3. Non-skin side layer (absorbent body),
3f latent crimp fiber (fiber),
4 Back sheet (outer layer),
5 side seats,
10 Absorbing layer (absorber),
20 Compression section,
DH high density part;
DL low density part,
Ru skin side region,
Rm intermediate region;
Qd non-skin side region;
Qu skin side area,
Qm intermediate region,
Qd Non-skin side area

Claims

An absorbent body for use in an absorbent article,
The nonwoven fabric comprises at least one nonwoven fabric having a plurality of fibers, the fibers including the latent crimp fibers.
A void formed by the plurality of fibers,
The absorbent body according to claim 1, wherein the weight of the latent crimped fiber divided by the weight of the plurality of fibers is 70% or more.
The absorbent body according to claim 1,
An absorbent body having an air flow resistance of 0.32 kpa·s/m or less.
The absorbent body according to claim 1 or 2,
An absorbent body, wherein the plurality of fibers are not fused to one another.
The absorbent body according to claim 1 or 2,
With a thickness direction,
A void formed by the plurality of fibers,
When the absorbent body is divided into three equal parts in the thickness direction, the region closest to the skin is defined as the skin side region, the region closest to the skin is defined as the non-skin side region, and an intermediate region is defined between the skin side region and the non-skin side region,
The average narrowness of the non-skin side region in a narrowness evaluation test for quantitatively evaluating the narrowness of the gap is
The absorbent body is characterized in that the narrowness is smaller than the average narrowness of the skin side region in the narrowness evaluation test.
The absorbent body according to claim 1 or 2,
With a thickness direction,
A void formed by the plurality of fibers,
When the absorbent body is divided into three equal parts in the thickness direction, the region closest to the skin is defined as the skin side region, the region closest to the skin is defined as the non-skin side region, and an intermediate region is defined between the skin side region and the non-skin side region,
The void ratio of the non-skin side region in a void ratio evaluation test for quantitatively evaluating the ratio of the voids in a predetermined region is
An absorbent body characterized in that the void ratio is smaller than the void ratio of the skin side region in the void ratio evaluation test.
The absorbent body according to claim 1 or 2,
With a thickness direction,
A void formed by the plurality of fibers,
When the absorbent body is divided into three equal parts in the thickness direction, the region closest to the skin is defined as the skin side region, the region closest to the skin is defined as the non-skin side region, and an intermediate region is defined between the skin side region and the non-skin side region,
An absorbent body, characterized in that the hydrophilicity of the skin side region is lower than the hydrophilicity of the non-skin side region.
The absorbent body according to claim 1 or 2,
With a thickness direction,
A void formed by the plurality of fibers,
When the absorbent body is divided into three equal parts in the thickness direction, the region closest to the skin is defined as the skin side region, the region closest to the skin is defined as the non-skin side region, and an intermediate region is defined between the skin side region and the non-skin side region,
At least a portion of the fibers in the non-skin side region have a higher hydrophilicity than the fibers in the skin side region;
An absorbent body, characterized in that a portion of the fibers in the non-skin side region is exposed on the skin side surface of the absorbent body.
The absorbent body according to claim 1 or 2,
having a thickness direction,
A first region is a region closer to the skin than a center in the thickness direction of the absorbent body,
When the non-skin side of the center in the thickness direction of the absorbent body is defined as a second region,
An absorbent body, characterized in that the maximum fiber thickness of the first region is greater than the maximum fiber thickness of the second region.
The absorbent body according to claim 1 or 2,
An absorbent body, characterized in that the basis weight of the plurality of fibers of the absorbent body is 80 gsm or more and 350 gsm or less.
The absorbent body according to claim 1 or 2,
The film has a longitudinal direction, a width direction, and a thickness direction,
The length of the absorbent body in the longitudinal direction is longer than the length of the absorbent body in the width direction,
An absorbent body, characterized in that a bending rigidity B of the absorbent body in a central portion in the longitudinal direction and in a central portion in the width direction is 1.2 gf·cm 2 /cm or less, as measured by a KES method.
The absorbent body according to claim 1 or 2,
The film has a longitudinal direction, a width direction, and a thickness direction,
The length of the absorbent body in the longitudinal direction is longer than the length of the absorbent body in the width direction,
An absorbent body, wherein a bending hysteresis 2HB of the absorbent body in the longitudinal direction and in the width direction is 0.93 gf·cm 2 /cm or less, as measured by a KES method.
The absorbent body according to claim 1 or 2,
The film has a longitudinal direction, a width direction, and a thickness direction,
The length of the absorbent body in the longitudinal direction is longer than the length of the absorbent body in the width direction,
An absorbent body, characterized in that the linearity LC of compression characteristics in a central portion of the absorbent body in the longitudinal direction and in the central portion of the absorbent body in the width direction is 0.6 or more, as determined by a KES method.
The absorbent body according to claim 1 or 2,
The film has a longitudinal direction, a width direction, and a thickness direction,
The length of the absorbent body in the longitudinal direction is longer than the length of the absorbent body in the width direction,
An absorbent body, characterized in that a compression resilience RC of the absorbent body in the longitudinal center and in the width direction is 38.0% or more, as measured by the KES method.
The absorbent body according to claim 1 or 2,
In an elongation test for measuring the magnitude of a force required to elongate the length of the absorbent body in the longitudinal direction to a length 1.3 times the length of the absorbent body in the longitudinal direction,
An absorbent body, characterized in that the value of the force magnitude obtained by measuring the 10th time in the elongation test of the absorbent body divided by the value of the force magnitude obtained by measuring the 1st time in the elongation test of the absorbent body is 50% or more.
An absorbent article comprising the absorbent body according to claim 1 or 2,
The film has a longitudinal direction, a width direction, and a thickness direction,
The length of the absorbent body in the longitudinal direction is longer than the length of the absorbent body in the width direction,
When viewed in the thickness direction, a central portion in the longitudinal direction and a central portion in the width direction of the absorbent article are defined as a predetermined region,
The weight of the predetermined area before absorbing distilled water is defined as a pre-absorption weight,
The weight of the predetermined area after immersing the predetermined area in distilled water for 60 seconds and then lifting it out of the distilled water and hanging it for 90 seconds is defined as the post-absorption weight.
When the value obtained by subtracting the weight before absorption from the weight after absorption is defined as the absorption weight of the distilled water,
An absorbent article, characterized in that a value obtained by dividing the absorption weight by the weight before absorption is 5 or more.