JP2022140913A - absorbent article - Google Patents

Abstract

To provide an absorbent article having an excellent side leakage preventing performance and also an excellent wearing comfort by reducing a load pressure applied to the legs of a wearer.SOLUTION: An absorbent core 6 has a laminate structure formed by superposing a first layer 7 and a second layer 8 in a thickness direction, where both layers 7 and 8 include particulate water-absorbing polymers. The second layer 8 includes, at least at a crotch part B, lateral extension parts 82 extending outward in a lateral direction Y from side edges along a longitudinal direction X of the first layer 7. The water-absorbing polymers in the second layer 8 have a flow rate under a pressure of 2.0 kPa, lower than that of the polymers in the first layer 7. According to one embodiment of the present invention, the first layer 7 includes a fiber assembly containing hydrophilic fibers, and the water-absorbing polymers are present in gaps between fibers of the fiber assembly. The second layer 8 includes a water-absorbing polymer layer 80 primarily composed of the water-absorbing polymers and containing no fibers.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an absorbent article worn on the crotch and used to absorb and hold excrement.

Absorbent articles such as disposable diapers and sanitary napkins generally comprise an absorbent body that absorbs and retains excrement, a surface sheet disposed on the skin facing side of the absorbent body, and a non-skin facing side of the absorbent body. and a backing sheet disposed on the The absorbent body includes an absorbent core mainly composed of a water-absorbent material, and conventionally, hydrophilic fibers such as wood pulp, particulate water-absorbent polymers, and the like are used as the water-absorbent material.

Patent Literature 1 describes an absorbent article having an absorbent body with a two-layer structure. This two-layer structure absorbent body has an upper absorbent body containing hydrophilic fibers and a lower absorbent body disposed on the non-skin facing side of the upper absorbent body, and the lower absorbent body comprises the upper absorbent body. It has an extension region extending in the longitudinal direction and the width direction from the absorbent body. Patent Document 1 describes that gel blocking and side leakage in the upper absorbent body can be prevented by making the basis weight of the water-absorbent polymer different between the extending regions of the upper absorbent body and the lower absorbent body. , it is not described that the types of water-absorbing polymers are different between the two absorbent bodies.

Patent Literature 2 describes an absorbent article that has an absorbent body that is anti-gel blocking while maintaining a high rate of absorption of excrement. The absorber described in Patent Document 2 includes a fiber layer having a three-dimensional network structure formed by heat-sealing a part of thermoplastic fibers, and disposed dispersedly in the fiber layer, and the absorption speed by the Vortex method is 25 seconds or less, the water-absorbent polymer particles are first particles arranged on the skin-side surface of the absorbent body, and arranged on the non-skin-facing surface side of the absorbent body, and a second particle having a particle size larger than that of the first particle.

In Patent Document 3, an absorbent layer containing a water absorbent resin and an adhesive is arranged between two nonwoven fabrics arranged facing each other as an absorbent body for an absorbent article that is thin and excellent in liquid absorption. configuration is described. The absorbent layer is divided into two layers in the thickness direction by a fiber substrate made of nonwoven fabric, and the saline flow conductivity (SFC) of one of the two layers is set to a specific range. ing.

JP 2019-162526 A JP 2013-252333 A JP 2012-218320 A

When the direction corresponding to the front-rear direction of the wearer of the absorbent article is taken as the longitudinal direction, and the direction perpendicular to the longitudinal direction is taken as the lateral direction, the absorption of the part (crotch part) of the absorbent article corresponding to the crotch part of the wearer When the length in the lateral direction of the body is lengthened, the absorption capacity of the absorbent body increases, and improvement in liquid absorption can be expected. Both legs (thighs) of the wearer present on both sides in the lateral direction are strongly pressed, which may lead to a decrease in wearing comfort. On the other hand, if the lateral length of the absorber in the crotch portion is shortened, the load pressure applied to the wearer's legs by such an absorber can be reduced, but there is a risk of a decrease in liquid absorbency, particularly excrement. So-called side leakage, in which the water leaks out in the lateral direction of the absorbent article, is a concern. No technology has yet been provided that can achieve both prevention of side leakage and reduction of load pressure on the wearer's legs.

TECHNICAL FIELD The present invention relates to providing an absorbent article that has excellent side leakage prevention performance, reduces the load pressure on the wearer's legs, and has excellent wearing comfort.

The present invention has a longitudinal direction extending from the wearer's abdomen to the dorsal side through the crotch part and a lateral direction orthogonal to the longitudinal direction, and has a crotch part arranged in the crotch part, and a crotch part from the crotch part. The absorbent article is divided into an abdominal portion arranged on the wearer's abdomen and a dorsal portion arranged on the wearer's back side rather than the crotch portion, and has an absorbent core for absorbing and holding excrement. It is a sexual item.
In one embodiment of the absorbent article of the present invention, the absorbent core is formed by laminating a first layer and a second layer disposed farther from the wearer's skin than the first layer in the thickness direction. It has a laminated structure, and the first layer and the second layer each contain a particulate water-absorbent polymer.
In one embodiment of the absorbent article of the present invention, the second layer has lateral extensions extending outward in the lateral direction from side edges along the longitudinal direction of the first layer at least in the crotch portion. have an outlet.
In one embodiment of the absorbent article of the present invention, the second layer has a lower liquid permeation speed under pressure of the water absorbent polymer at 2.0 kPa than the first layer.
Other features, advantages and embodiments of the invention are described below.

ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which is excellent in side leak prevention performance, the load pressure to a wearer's leg is reduced, and is excellent in a feeling of wearing is provided.

FIG. 1 is a schematic expanded plan view of the side facing the skin (top sheet side) of a disposable diaper, which is one embodiment of the absorbent article of the present invention, in an expanded and stretched state. FIG. 2 is a schematic cross-sectional view of the cross section taken along the line II of FIG. 1 (the cross section along the thickness direction and lateral direction of the absorbent article). FIG. 3 is a schematic cross-sectional view showing an enlarged absorber shown in FIG. FIG. 4 is a schematic cross-sectional view along the thickness direction and lateral direction of the absorbent core in the crotch portion when the diaper shown in FIG. 1 is worn.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on its preferred embodiments with reference to the drawings. In addition, in the following description of the drawings, the same or similar reference numerals are given to the same or similar parts. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

1 and 2 show a disposable diaper 1 which is one embodiment of the absorbent article of the present invention. The diaper 1 has a longitudinal direction X corresponding to the front-rear direction of the wearer, that is, a direction extending from the abdominal side to the back side through the crotch portion, and a lateral direction Y perpendicular to the longitudinal direction X. As shown in FIG. Further, the diaper 1 includes a crotch portion B including an excretory portion facing portion (not shown) that is arranged in the wearer's crotch portion and faces the excretory portion such as the penis, and a wearer's abdominal side ( It is divided into three parts: an abdominal part A arranged on the front side) and a dorsal part C arranged on the back side (rear side) of the wearer from the crotch part B.

In this embodiment, the diaper 1 is formed symmetrically on one side and the other side with respect to the lateral center line CLy in the unfolded and stretched state as shown in FIG.
The abdomen portion A is part of the front body F of the diaper 1 , and the back portion C is part of the back body R of the diaper 1 . The crotch part B straddles the longitudinal center line CLx in the longitudinal direction X and exists over both the front body F and the back body R. The crotch portion B typically includes a region in which leg edges LS, LS, which are recessed portions for forming leg openings, are formed. The leg edges LS are part of both side edges along the longitudinal direction X of the backsheet 4 .
In the present invention, the abdominal portion A, the crotch portion B, and the back portion C can be respective regions when the diaper 1 in the unfolded and stretched state is divided into three equal parts in the longitudinal direction X.

The horizontal center line CLy is an imaginary straight line extending in the vertical direction X by dividing the diaper 1 in the unfolded and stretched state into two halves in the horizontal direction Y. As shown in FIG. The vertical center line CLx is an imaginary straight line that extends in the horizontal direction Y by halving the diaper 1 in the unfolded and stretched state in the vertical direction X. As shown in FIG.
The above-mentioned "unfolded and stretched state" means that the absorbent article is spread into a flat state to be in a stretched state, and the elastic members of each part of the absorbent article in the stretched state are stretched to the design dimensions (the influence of the elastic members is completely eliminated). It is the same as the dimension when it is spread flat in the state).

In this embodiment, the diaper 1 comprises, as shown in FIG. , 4, and these members 3, 4, 5 constitute the absorbent main body 2. As shown in FIG. Each member constituting the absorbent main body 2 is integrated by joining means such as an adhesive or fusion. The topsheet 3 covers the entire skin-facing surface of the absorbent body 5 , and the backsheet 4 covers the entire non-skin-facing surface of the absorbent body 5 . The top sheet 3 and the back sheet 4 each extend outward in the longitudinal direction X from both ends of the absorbent body 5 in the longitudinal direction X, and extend in the lateral direction Y from both side edges along the longitudinal direction X of the absorbent body 5 . It extends outward. The backsheet 4 extends further outward in the lateral direction Y than the topsheet 3 at least in the lateral direction Y, and forms the outer shape of the diaper 1 in the unfolded state as shown in FIG.

As used herein, the term "skin-facing surface" refers to the surface facing the wearer's skin when the absorbent article is worn, when focusing on the absorbent article or its constituent members (e.g., absorbent body). "Facing side" is the side facing away from the wearer's skin when the absorbent article is worn. That is, the skin-facing surface is the surface relatively close to the wearer's skin, and the non-skin-facing surface is the surface relatively far from the wearer's skin. In addition, "when worn" and "worn state" refer to a state in which the absorbent article is worn while maintaining an appropriate wearing position.

Constituent members of the absorbent main body 2 are limited to those commonly used in this type of absorbent article, on the premise that if there is a description of the member later, the description can be applied. can be used without As the surface sheet 3, various liquid-permeable sheets can be used, such as nonwoven fabric, woven fabric, and paper. As the back sheet 4, a sheet having a leakproof property, specifically, a liquid-impermeable (absolutely liquid-impermeable) or liquid-impermeable (although it cannot be said to be liquid-impermeable, it is difficult for liquid to pass through). properties), and examples thereof include a moisture-permeable resin film and a laminate of the resin film and a nonwoven fabric.

In this embodiment, the diaper 1 is provided with a pair of leak-proof cuffs 10, 10 arranged along both sides along the longitudinal direction X of the absorbent body 2. As shown in FIG. Each leak-proof cuff 10 includes a liquid-impermeable and breathable leak-proof sheet 11, and one end side of the leak-proof sheet 11 in the horizontal direction Y is attached to another member (back sheet 4 in the form shown in FIG. 2). The other end of the leakproof sheet 11 in the horizontal direction Y is a free end that is not fixed to another member. At the free end of the leak-proof sheet 11, a leak-proof cuff-forming elastic member 12 is fixed in a stretched state in the longitudinal direction X so as to be stretchable in the same direction. When the diaper 1 is put on, the contractile force of the elastic member 12 causes the free end portion of the leak-proof sheet 11 to stand up toward the wearer at least in the crotch portion B with the fixed end portion as the standing base end, thereby forming a pair. The anti-leakage cuffs 10, 10 are erected to prevent excretion such as urine from flowing outward in the lateral direction Y. 2 shows the leak-preventing cuff 10 in an upright state for convenience of explanation, the leak-preventing cuff 10 necessarily stands up as shown in FIG. Not that.

As shown in FIG. 1, the diaper 1 includes a pair of fastening tapes 13, 13 arranged on both side edges along the longitudinal direction X of the dorsal portion C, and an abdominal side. a fastening member 15 disposed on the non-skin facing surface of the part A (the non-skin facing surface of the back sheet 4) and capable of detachably fastening the engaging portion 14 of each fastening tape 13; 1, the engaging portion 14 is fastened to the fastening member 15. As shown in FIG.

In this embodiment, as shown in FIG. 2, the diaper 1 includes a flap portion 16 located outside the periphery of the absorbent body 5 (absorbent main body 2). The flap portion 16 is composed of a member arranged to straddle the periphery of the absorbent body 5 , and includes the top sheet 3 , the back sheet 4 and the leak-proof sheet 11 in the illustrated embodiment. A plurality of members forming the flap portion 16 are joined together by known joining means such as adhesive, heat sealing, and ultrasonic sealing. Side flap portions 17 are portions of the flap portion 16 positioned outside in the horizontal direction Y from both side edges along the longitudinal direction X of the absorbent body 5 and imaginary extension lines of the both side edges. Leg gather forming elastic members 18 are stretchably arranged along the leg edges LS (longitudinal direction X) at least in the crotch portion B of each of the pair of side flap portions 17 , 17 . When the diaper 1 is worn, due to the contraction of the elastic members 18, the sheets forming the leg edges LS (the back sheet 4 and the leak-proof sheet 11 in the illustrated embodiment) are stretched in a direction intersecting the contraction direction of the elastic members 18. A plurality of extending pleats (gathers) are formed such that leg gathers are formed in which the pleats are substantially continuous all the way around the legs of the wearer.

The absorbent body 5, which is a characteristic part of the diaper 1, will be described in detail below.
In this embodiment, as shown in FIG. 1, the absorbent body 5 has a shape elongated in one direction (rectangular shape in the embodiment shown in FIG. 2) in a plan view, and the longitudinal direction and the longitudinal direction X of the diaper 1 are aligned. arranged to match. The absorbent body 5 is arranged at least in the crotch part B, and in this embodiment, the absorbent body 5 is arranged so as to extend from the abdominal part A to the back side part C via the crotch part B. As shown in FIG. Both longitudinal side edges (both side edges along the longitudinal direction X) of the absorbent body 5 are located inward of both side edges along the longitudinal direction X of the diaper 1 .

In the present embodiment, the absorbent body 5 includes an absorbent core 6 that forms the main body of the absorbent body 5 and absorbs and retains excrement, and a core wrap sheet 9 that covers the outer surface of the absorbent core 6 . As the core wrap sheet 9, a liquid-permeable sheet can be used, and for example, paper, nonwoven fabric, or woven fabric can be used. In the form shown in FIG. 2 , the skin-facing surface and the non-skin-facing surface of the absorbent core 6 are covered with one core wrap sheet 9 , but the absorbent body 5 includes a plurality of core wrap sheets 9 . Also, for example, one skin-side core wrap sheet covering the skin-facing surface of the absorbent core 6 and one non-skin-side core wrap sheet covering the non-skin-facing surface of the absorbent core 6 You can stay.
In addition, in the present invention, the core wrap sheet 9 is not essential, and the absorbent body 5 may be composed only of the absorbent core 6 .

The absorbent core 6 has a laminated structure in which a first layer 7 and a second layer 8 arranged on the side farther from the wearer's skin than the first layer 7 are laminated in the thickness direction. Therefore, excrement such as urine excreted by the wearer of the diaper 1 normally moves through the absorbent core 6 in the thickness direction in the order of the first layer 7 and the second layer 8 .

In this embodiment, as shown in FIG. The absorbent core 6 has a two-layer structure of a first layer 7 and a second layer 8, which is in contact with the skin-facing surface.
In the present invention, another member (for example, a sheet made of the same material as the core wrap sheet 9) is interposed between the first layer 7 and the second layer 8 on the condition that the gist of the present invention is not deviated. The absorbent core 6 may have a laminated structure of three or more layers.

The first layer 7 and the second layer 8 each contain a particulate water-absorbing polymer. Symbol P in the figure is a water absorbing polymer. As the water-absorbent polymer contained in both layers 7 and 8, those that can be used for this type of absorbent article can be used without any particular limitation, provided that they comply with the description to be described later. can use a hydrogel material capable of absorbing and retaining water, for example, a polymer or copolymer of acrylic acid or an alkali metal salt of acrylic acid. Examples thereof include polyacrylic acid and its salts and polymethacrylic acid and its salts, specifically acrylic acid polymer partial sodium salts. The shape of the particulate water-absorbing polymer is not particularly limited, and may be, for example, spherical, tufted, lumpy, bale-shaped, fibrous, amorphous, or combinations thereof.

In this embodiment, the first layer 7 has a fiber assembly containing hydrophilic fibers, and the water-absorbing polymer exists in the inter-fiber voids of the fiber assembly. The first layer 7 is a so-called fiber stack type absorbent core. The first layer 7 mainly composed of such a fiber aggregate typically contains a water-absorbing polymer and does not contain fibers, such as the water-absorbing polymer layer 80 included in the second layer 8, which will be described later. The absorbent polymer is dispersed throughout the fiber assembly.
In the first layer 7 mainly composed of fiber aggregates, the water-absorbent polymer may be uniformly distributed throughout the first layer 7, or may be unevenly distributed to such an extent that the water-absorbent polymer layer is not formed. good. As a specific example of the latter, a form in which the water-absorbing polymer is unevenly distributed on the skin-facing side or the non-skin-facing side of the first layer 7, that is, one of the skin-facing side and the non-skin-facing side is the other. A form in which the content of the water-absorbing polymer is higher than that in the above can be exemplified. The skin-facing side of the first layer 7 and the non-skin-facing side of the first layer 7 are separated by an imaginary straight line (not shown) that bisects the first layer 7 in the thickness direction.

As the hydrophilic fibers contained in the first layer 7, those that can be used in this type of absorbent core can be used without particular limitation. Examples thereof include cellulose fibers and hydrophilic synthetic fibers. It can be used alone or in combination of two or more. Cellulose fibers include natural fibers such as wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as cotton pulp and hemp pulp; modified pulp such as cationized pulp and mercerized pulp; regenerated fibers such as cupra and rayon. is mentioned.
The content of the hydrophilic fibers in the first layer 7 is preferably 50% by mass or more, and may be 100% by mass, based on the total mass of the fibers contained in the first layer 7 . The first layer 7 may contain fibers other than hydrophilic fibers, such as hydrophobic thermoplastic fibers.

Although the basis weight of the first layer 7, the content of the forming material, and the like are not particularly limited, they can be set as follows from the viewpoint of ensuring that the first layer 7 exhibits a predetermined effect. In particular, when the first layer 7 is mainly composed of the above-mentioned fiber assembly, it is preferable to set as follows.
The basis weight of the first layer 7 is preferably 50 m ² or more, more preferably 100 g/m ² or more, and preferably 1000 g/m ² or less, more preferably 800 g/m ² or less.
The content of fibers in the first layer 7 is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass, based on the total mass of the first layer 7. % by mass or less.
The content of the water-absorbing polymer in the first layer 7 is preferably 20% by mass or more, more preferably 50% by mass or more, and preferably 80% by mass or less, more preferably, with respect to the total mass of the first layer 7. is 90% by mass or less.

The first layer 7 can be manufactured according to a conventional method using a known fiber stacking device equipped with a rotating drum. A fiber stacking device typically has a rotating drum having a collecting recess formed on its outer peripheral surface, and a channel for conveying a forming material (fibers, particulate water-absorbent polymer) to the collecting recess. and a duct, wherein the forming is conveyed on the air flow generated in the flow path by suction from the inside of the rotating drum while rotating the rotating drum around the rotating shaft along the circumferential direction of the drum. The material is stacked in the stacking concave portion. A first layer 7 is formed in the stacking concave portion by such a stacking step.

In this embodiment, the second layer 8 includes a water-absorbing polymer layer 80 that contains a water-absorbing polymer and does not contain fibers, as shown in FIGS. Here, "does not contain fiber" includes not only a form in which the content of fiber is zero, but also a form in which fiber is contained in the water-absorbing polymer layer 80, but the content of the fiber is substantially zero. (preferably 10% by mass or less, more preferably 5% by mass or less with respect to the total mass of the water-absorbent polymer layer 80). The second layer 8 is a so-called sheet-type absorbent core.

In this embodiment, the second layer 8 includes two base sheets 81, 81 that are arranged opposite to each other in the thickness direction of the second layer 8, and the water-absorbing polymer layer 80 is composed of the two base sheets. It is interposed between 81,81. The two base sheets 81, 81 may be identical to each other, or may differ in one or more characteristics such as configuration, material, physical properties, and the like.

The water-absorbent polymer layer 80 typically contains an adhesive such as a hot-melt adhesive, and the adhesive bonds the water-absorbent polymers constituting the water-absorbent polymer layer 80 together, The two base sheets 81, 81 and the base sheet 81 and the water absorbent polymer are bonded together.
Although the basis weight of the water-absorbent polymer layer 80 is not particularly limited, it is preferably 5 g/m ² or more, more preferably 20 g/m ² or more, from the viewpoint of ensuring the predetermined effects of the second layer 8. And it is preferably 1000 g/m ² or less, more preferably 800 g/m ² or less.

As the base sheet 81, a liquid-permeable or liquid-absorbent sheet can be used. The base sheet 81 is typically a fiber sheet mainly composed of fibers, that is, the fiber content exceeds 50% by mass.
Examples of the constituent fibers of the base sheet 81 include natural fibers such as wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as cotton pulp and hemp pulp; modified pulp such as cationized pulp and mercerized pulp. , cellulose fibers); and synthetic fibers containing resins such as polyethylene and polypropylene.
Examples of the form of the base sheet 81 include paper, woven fabric, and nonwoven fabric. Nonwoven fabrics include, for example, air through nonwoven fabric, heat roll nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, and spunbond-meltblown-. Spunbond (SMS) nonwovens may be mentioned. The base sheet 81 typically has a single-layer structure consisting of one of these types, but may have a laminated structure in which two or more types are laminated and integrated.
Although the basis weight of the base sheet 81 is not particularly limited, it is preferably 5 g/m ² or more, more preferably 8 g/m ² or more, and , preferably 100 g/m ² or less, more preferably 80 g/m ² or less.

As shown in FIG. 3, the second layer 8 has, at least at the crotch portion B, laterally extending portions 82 extending outward in the lateral direction Y from the side edges 7S along the longitudinal direction X of the first layer 7. have.
In this embodiment, as shown in FIG. 1, a pair of laterally extending portions 82 are present on both sides in the lateral direction Y with the first layer 7 interposed therebetween. extend continuously over the entire length of the second layer 8 in the longitudinal direction X, and are present not only in the crotch portion B but also in the ventral portion A and the dorsal portion C. As shown in FIG. A lateral length Ly82 (see FIG. 3) of the laterally extending portion 82 is constant over the entire length in the longitudinal direction X of the laterally extending portion 82 .
In the present invention, the laterally extending portion 82 only needs to exist at least in the crotch portion B, and its plan view shape and the like are not particularly limited. and the lateral length Ly82 may be partially different. Also, a plurality of laterally extending portions 82 may exist discontinuously in the longitudinal direction X. As shown in FIG.

Thus, the fact that only the second layer 8 of the first layer 7 and the second layer 8 constituting the absorbent core 6 has the laterally extending portion 82 in the crotch portion B means that the crotch portion The first layer 7, which is located at the same position in the longitudinal direction X as the laterally extending portion 82 in B, has a shorter length (width) in the lateral direction Y than the second layer 8, and is as lateral as the second layer 8. That is, it does not protrude in the Y direction. When the diaper 1 having the absorbent core 6 having such a configuration is worn in a conventional manner, as shown in FIG. Since the legs (thighs) 91, 91 are pinched and can be compressed in the lateral direction Y, the crotch portion 90 side of the leg 91 is pressed by the lateral Y end of the absorbent core 6. , the wearer perceives the load pressure on the leg 91 and may be dissatisfied with the feeling of wearing. However, in the diaper 1, the second layer 8 extends further outward in the lateral direction Y than the first layer 7 at the crotch portion B corresponding to the crotch portion 90 of the wearer, as shown in FIG. Therefore, it is mainly the second layer 8 (laterally extending portion 82) that presses the legs 91 while the diaper 1 is being worn, and the opportunity and pressing force of the first layer 7 to press the legs 91 are reduced. Therefore, compared to the case where the lateral length of the absorbent core (absorbent body) is the same throughout the entire thickness direction as in conventional absorbent articles, the load pressure on the legs 91 is reduced and the wearing comfort is improved. Improvement of feeling is planned.

Particularly in this embodiment, the second layer 8 (laterally extending portion 82), which is the main factor of the load pressure on the wearer's leg, is mainly made of a fiber assembly containing hydrophilic fibers and has a relatively large thickness. Rather than a high-rigidity so-called laminated fiber-type absorbent core, the so-called sheet-type absorbent core is mainly composed of the water-absorbing polymer layer 80 and has a relatively thin thickness and low rigidity. is further reduced, and the feeling of wearing is further improved. In general, sheet-type absorbent cores are thinner and more flexible than fiber-stacked absorbent cores.
As an advantage of the absorbent core having a two-layer structure consisting of a piled-type absorbent core and a sheet-type absorbent core, it is possible to reduce the thickness of the absorbent core while ensuring a certain level of leakage performance. The point is that it is possible to plan

From the viewpoint of more reliably exhibiting the effects of the laterally extending portion 82 of the second layer 8 described above, the portion where the laterally extending portion 82 of the absorbent core 6 exists, as shown in FIG. , the ratio of the lateral length Ly7 (see FIG. 3) of the first layer 7 to the lateral length Ly8 (see FIG. 3) of the second layer 8 (Ly7/ Ly8) is preferably 0.83 or less, more preferably 0.58 or less. In addition, the lower limit of the Ly7/Ly8 ratio is preferably 0.25 or more, more preferably 0.4 or more, from the viewpoint of ensuring the liquid absorption capacity of the first layer 7 and the like.
The lateral length Ly7 of the first layer 7 is specifically For example, when the first layer 7 has a space such as a slit or a through hole, it includes the length in the horizontal direction Y of the non-existing space (space) of such forming material. The same applies to the lateral length Ly8 of the second layer 8 .

From the same viewpoint as above, the lateral length Ly82 (see FIG. 3) of the laterally extending portion 82 is preferably 10 mm or more, more preferably 25 mm or more, and preferably 50 mm or less, more preferably 40 mm or less. be.

By the way, when the laterally extending portion 82 is provided in the second layer 8 of the crotch portion B, the length in the lateral direction Y of the portion at the same position in the longitudinal direction X as the laterally extending portion 82 in the first layer 7 is , the lateral direction Y of the first layer 7 becomes shorter than when the laterally extending portion 82 is not provided (when the length of the lateral direction Y is the same between the first layer 7 and the second layer 8). The absorption capacity of excreta in the body is reduced. As a result, a relatively large amount of excrement migrates to the second layer 8, and the excrement that has migrated to the second layer 8 is diffused in the second layer 8 in the lateral direction Y and spreads laterally of the second layer 8. There is a concern that so-called side leakage, which is leakage to the outside from the end in the direction Y, is likely to occur.
However, in the present invention, a configuration is adopted in which "the second layer 8 has a lower liquid permeation rate under pressure of the water-absorbent polymer at 2.0 kPa than the first layer 7". Since the permeation/diffusion rate of excreta such as urine is lower than that of the first layer 7, side leakage is less likely to occur in the second layer 8, and the above concern is dispelled.
In this way, the diaper 1 has the laterally extending portion 82 of the second layer 8 in the crotch portion B (the first layer 7 is laterally larger than the second layer 8 in a cross-sectional view along the thickness direction and lateral direction Y). There is a short portion in the direction Y), so the load pressure on the wearer's legs is low and the feeling of wearing is excellent. The relationship of "first layer 7 > second layer 8" is established with respect to the liquid permeation rate under pressure of 2.0 kPa of the liquid polymer, and the occurrence is effectively prevented. is also excellent.

In particular, when the first layer 7 is a fiber-stacked type absorbent core as in the present embodiment, the first layer 7 can function as a flow path for liquid (excretion) between adjacent water-absorbent polymers. However, since the hydrophilic fibers are present, the permeation and diffusion of the liquid through the channels may be hindered by the hydrophilic fibers, and there is concern that the liquid permeability of the first layer 7 may be reduced. . Further, when the second layer 8 is a sheet-type absorbent core including the water-absorbing polymer layer 80 as in the present embodiment, the fibers are substantially separated between adjacent water-absorbing polymers in the water-absorbing polymer layer 80. Since it does not exist, the pressure loss is relatively small, and as a result, the liquid (excretion) is likely to spread in the lateral direction Y, and lateral leakage is likely to occur. However, a problem peculiar to the laminated structure of such a laminated fiber type absorbent core (first layer 7) and a sheet type absorbent core (second layer 8) is The problem can be solved by establishing a relationship of "first layer 7>second layer 8" with respect to the liquid permeation speed under pressure.

The liquid permeation rate under pressure can be an index of the diffusion/permeation rate of the liquid in the absorbent core containing the water-absorbent polymer, and the decrease in the liquid permeation rate under pressure is caused by the pressure applied to the absorbent core. It is caused by narrowing of the liquid flow path (gel blocking) in the absorbent core due to adhesion of swollen water-absorbing polymers. Compared to the first layer 7, the second layer 8 has a lower liquid permeation rate under pressure of 2.0 kPa of the water-absorbent polymer, and gel blocking tends to hinder diffusion of liquid (excretion) and decrease liquid permeability. Therefore, the diffusion/permeation speed of liquid (excretion) is lower than that of the first layer 7, and therefore side leakage is less likely to occur. On the other hand, the first layer 7, which is closer to the wearer's skin than the second layer 8, has a higher liquid permeation rate under pressure of 2.0 kPa of the water-absorbing polymer than the second layer 8, and the liquid due to gel blocking ( Since diffusion inhibition of excrement) and decrease in liquid permeability are unlikely to occur, the diffusion and permeation speed of liquid (excretion) is higher than that of the second layer 8, and therefore less liquid remains, and the topsheet 3 feels dry. It is possible to expect effects such as an improvement in the water resistance and prevention of liquid return. An applied force of 2.0 kPa approximately corresponds to the pressure applied to the absorbent core when the absorbent article is worn. The liquid permeation rate under pressure is measured by the following method.

<Method for measuring liquid permeation rate under pressure>
This measurement method conforms to the measurement method described in Japanese Patent Laid-Open No. 2003-235889 (especially see [0008], [0009], FIG. 1, FIG. 2, etc.), specifically in the following procedure. done. This measurement method is performed at 23±2° C. and 50±5% relative humidity. Before the measurement, the water-absorbent polymer, which is a measurement sample, is stored in the same environment for 24 hours or longer.
First, in a 200 mL glass beaker, 0.32 ± 0.005 g of the water-absorbing polymer, which is a measurement sample, and a sufficient amount of physiological saline to swell it (for example, 5 times the saturated absorption amount of the water-absorbing polymer) 0.9 mass % sodium chloride solution) is added, and the water-absorbing polymer is left to stand for 30 minutes while being immersed in the physiological saline.
Next, a wire mesh (opening 150 μm, biocolumn sintered stainless steel filter 30 SUS manufactured by Sansho Co., Ltd.) and a thin tube with a cock (inner diameter 2 mm) were placed at the lower end of the opening of a vertical cylinder (inner diameter 25.4 mm). (inner diameter: 4 mm, length: 8 cm) is arranged, and with the cock closed, the contents of the beaker including the swollen measurement sample are put into the cylinder. Then, the cock is opened to adjust the liquid level in the cylinder to 5 cm above the 60 mL scale line (initial liquid level position).
Next, a cylindrical rod with a diameter of 2 mm having a wire mesh (opening of 150 μm, diameter of 25 mm) at the tip is inserted into the filtration cylindrical tube so that the wire mesh of the cylindrical rod and the measurement sample are in contact, and furthermore, the measurement sample is Place a weight so that a load of 2.0 kPa is applied to the After being left in this state for 1 minute, the cock is opened and the liquid is allowed to flow from the wire mesh arranged at the lower end of the cylinder provided in the filtration cylindrical tube, and the liquid level in the filtration cylindrical tube rises from the initial liquid level position. Measure the time until 20 mL decrease (the time required for 20 mL of physiological saline to pass through the filtration cylindrical tube containing the water-absorbing polymer) T ₁ (seconds), and use the following formula to calculate the measurement sample Calculate the liquid permeation rate under pressure at 2.0 kPa. “T ₀ ” in the following formula is the time (seconds) required for 20 mL of physiological saline to pass through the filtration cylindrical tube containing no water-absorbent polymer.
Liquid permeation rate under pressure (mL / min) = 20 × 60 / (T ₁ - T ₀ )
The measurement is performed five times for one type of measurement sample (first layer or second layer water-absorbent polymer), and the average value of the remaining three points is taken as the measured value, except for the values at one point each above and below.

From the viewpoint of further ensuring the effect (prevention of side leakage) due to the establishment of the magnitude relationship of the liquid permeation speed under pressure described above, the water-absorbing polymer of the second layer 8 is passed under pressure at 2.0 kPa. The ratio (the latter/former) of the water permeation speed under pressure of 2.0 kPa of the water-absorbent polymer of the first layer 7 to the liquid speed is preferably 2.8 or more, more preferably 83 or more. From the viewpoint of preventing side leakage, the ratio is preferably as large as possible, and the upper limit does not have to be considered. 300 or less, more preferably 200 or less.
On the premise that the water-absorbent polymer of the first layer 7 has a liquid permeation rate under pressure of 2.0 kPa higher than that of the second layer 8, it is preferably 30 mL/min or more, more preferably 50 mL/min or more, And it is preferably 1000 mL/min or less, more preferably 400 mL/min or less.
On the premise that the water-absorbing polymer of the second layer 8 has a liquid permeation rate under pressure of 2.0 kPa that is smaller than that of the first layer 7, it is preferably 0.1 mL/min or more, more preferably 2 mL/min. above, and preferably 150 mL/min or less, more preferably 100 mL/min or less.

In the case where the first layer 7 is a laminated fiber type absorbent core and the second layer 8 is a sheet type absorbent core as in the present embodiment, the second layer 8 has It is preferable that the water absorption rate of the water-absorbing polymer by the VORTEX method is large (fast). The water absorption speed obtained by the vortex method can serve as an indicator of the speed at which the water-absorbing polymer fixes the liquid, and is suitable for evaluating the liquid-fixing ability of the water-absorbing polymer. The second layer 8 constitutes the water-absorbent polymer layer 80 because the water-absorbent polymer layer 80 that forms the basis of its liquid-absorbency does not substantially contain hydrophilic fibers that can contribute to the improvement of the liquid-absorbency. From the viewpoint of preventing lateral leakage more reliably by giving the water-absorbent polymer a certain level or more of liquid fixing ability, the relationship of "first layer 7 < second layer 8" is established for the water absorption rate by the vortex method. preferably. The water absorption rate by the vortex method is measured by the following method.
In the present invention, the time required for the water-absorbing polymer to be measured to absorb a predetermined amount of physiological saline is used as an indicator of the water absorption rate by the vortex method. Since the water absorption rate of the water-absorbing polymer is evaluated as high (fast), the numerical value (seconds) of the water-absorbing rate of the water-absorbing polymer of the second layer 8 by the vortex method is preferably smaller than that of the first layer 7. .

<Method for measuring water absorption rate by vortex method>
This measurement method conforms to JIS K 7224 (1996), and is specifically performed according to the following procedure. This measurement method is performed at 23±2° C. and 50±5% relative humidity. Before the measurement, the water-absorbent polymer, which is a measurement sample, is stored in the same environment for 24 hours or more.
In a 100 mL glass beaker, 50 mL of physiological saline (0.9% by mass sodium chloride solution) and a magnetic stirrer tip (central diameter 8 mm, both ends diameter 7 mm, length 30 mm, the surface of which is coated with fluorine resin) ), and place the beaker on a magnetic stirrer (HPS-100 manufactured by AS ONE). Adjust the rotational speed of the magnetic stirrer to 600±60 rpm to stir the physiological saline. 2.0 g of the water-absorbent polymer, which is a measurement sample, is put into the liquid at the center of the vortex of the salt water being stirred, and the water absorption speed (seconds) of the water-absorbent polymer is measured in accordance with JIS K 7224 (1996). Measure. Specifically, start the stopwatch when the addition of the water-absorbing polymer to the beaker is complete, and stop when the stirrer tip is covered with the test liquid (when the vortex disappears and the liquid surface becomes flat). Stop the watch and record the time (in seconds) as the vortex absorption rate.
The measurement is performed five times for one type of measurement sample (first layer or second layer water-absorbent polymer), and the average value of the remaining three points is taken as the measured value, except for the values at one point each above and below.

From the viewpoint of more reliably exhibiting the effect of establishing the magnitude relationship of the water absorption speed by the vortex method described above, the water absorption speed (seconds) of the water-absorbing polymer of the first layer 7 by the vortex method and the second layer 8 The ratio of the water absorption rate (seconds) by the vortex method of the water-absorbing polymer is, on the premise that the former > the latter, the former / the latter is preferably 1.1 or more, more preferably 1.4 or more, and preferably 6 below, and more preferably 4 or below.
On the premise that the water absorption speed (seconds) of the water-absorbent polymer of the first layer 7 by the vortex method is higher than that of the second layer 8 (that is, the speed is slow), it is preferably 30 seconds or more, more preferably 40 seconds. seconds or more, preferably 120 seconds or less, more preferably 60 seconds or less.
On the premise that the water absorption rate (seconds) of the water-absorbing polymer of the second layer 8 by the vortex method is smaller than that of the first layer 7 (that is, the rate is faster), it is preferably 10 seconds or more, more preferably 20 seconds. seconds or more, preferably 40 seconds or less, more preferably 30 seconds or less.

In the case where the first layer 7 is a laminated fiber type absorbent core and the second layer 8 is a sheet type absorbent core as in the present embodiment, the second layer 8 has It is preferable that the average particle size of the water-absorbent polymer is small. As a result, the second layer 8 has a larger specific surface area of the water-absorbent polymer than the first layer 7, so that the liquid absorption speed of the second layer 8 can be expected to be further improved, and side leakage is more assured. can be prevented.

The "average particle size of the water-absorbent polymer" is, for example, the skin-facing surface or non-skin-facing surface of the absorbent core (first layer 7, second layer 8) to be measured, using a microscope. A photograph can be taken at a magnification, the diameter (maximum span length) of each of the plurality of water-absorbent polymer particles in the photographed photograph can be measured, and the arithmetic mean value of the plurality of measured values can be calculated.
More specifically, for example, in a photograph of the skin-facing surface or non-skin-facing surface of the absorbent core taken with a microscope at an observation magnification of 40 times, a square unit area having an area of 1 square centimeter in plan view is arbitrarily setting, the diameter of each water-absorbing polymer particle present in the unit area is measured, and the arithmetic mean value thereof is calculated. The measurement is performed three times for one type of measurement object (for example, the first layer 7), and the arithmetic mean value of the three measurements is taken as the average particle size of the one type of water-absorbent polymer to be measured. In the case of the first layer 7, the surface to be photographed with a microscope is the skin-facing surface, and in the case of the second layer 8, the non-skin-facing surface. In addition, when the skin-facing surface of the absorbent core to be measured is covered with another member such as a core wrap sheet, microscopic photography is performed with the other member removed.

From the viewpoint of more reliably exhibiting the effect of establishing the above-described size relationship of the average particle size of the water-absorbing polymer, the average particle size of the water-absorbing polymer of the first layer 7 and the water-absorbing property of the second layer 8 The ratio of the average particle size of the polymer is premised on the former > the latter, and the former/latter is preferably 1.05 or more, more preferably 1.3 or more, and preferably 4 or less, more preferably 3 or less. be.
Assuming that the average particle size of the water-absorbent polymer of the first layer 7 is larger than that of the second layer 8, it is preferably 300 μm or more, more preferably 400 μm or more, and preferably 1000 μm or less, more preferably 850 μm. It is below.
On the premise that the average particle size of the water-absorbent polymer of the second layer 8 is smaller than that of the first layer 7, it is preferably 100 μm or more, more preferably 200 μm or more, and preferably 600 μm or less, more preferably 500 μm. It is below.

The absorbent article of the present invention is not limited to the spreadable disposable diaper as in the above embodiment, but broadly includes articles used for absorbing excrement (urine, menstrual blood, loose stool, sweat, etc.) excreted from the human body. , pants-type disposable diapers, sanitary napkins, sanitary shorts, etc., which do not have a fastening structure such as the fastening tape 13 and fastening member 15 .

Although the present invention has been described based on the embodiments, the present invention is not limited to the above embodiments and can be modified as appropriate.
For example, in the above-described embodiment, the first layer 7 is a so-called fiber-laminated absorbent core mainly composed of a fiber assembly containing hydrophilic fibers, and the second layer 8 includes a water-absorbent polymer layer 80. Although it was a so-called sheet type absorbent core, in the present invention, the form of both layers 7 and 8 is not limited to this, and can be appropriately set within the scope of the present invention. Both 7 and the second layer 8 may be of the fiber stack type or sheet type, or the first layer 7 may be of the sheet type and the second layer 8 may be of the fiber stack type. However, the most preferred is the embodiment described above.
In addition, from the viewpoint of improving absorbency, leakproofness, etc., a liquid-permeable sheet made of paper or various nonwoven fabrics, which is also called a second sheet or a sublayer sheet, is interposed between the surface sheet 3 and the absorbent body 5. may have been

The following notes are further disclosed with respect to the above-described embodiments of the present invention.
<1>
A crotch portion having a longitudinal direction extending from the wearer's abdomen to the back side through the crotch portion and a lateral direction orthogonal to the longitudinal direction, and a crotch portion arranged in the crotch portion, and a wearer's body extending from the crotch portion. An absorbent article comprising an absorbent core that is divided into an abdominal portion arranged on the abdomen side and a dorsal portion arranged on the back side of the wearer from the crotch portion and that absorbs and retains excrement. hand,
The absorbent core has a laminated structure in which a first layer and a second layer arranged farther from the wearer's skin than the first layer are laminated in a thickness direction. The second layers each contain a particulate water-absorbing polymer,
The second layer has, at least in the crotch portion, a laterally extending portion extending outward in the lateral direction from a side edge along the longitudinal direction of the first layer,
In the absorbent article, the second layer has a lower liquid permeation rate under pressure of the water-absorbent polymer at 2.0 kPa than the first layer.
<2>
The first layer has a fiber assembly containing hydrophilic fibers, and the water-absorbent polymer is present in inter-fiber voids of the fiber assembly,
The absorbent article according to <1>, wherein the second layer includes a water-absorbing polymer layer containing the water-absorbing polymer and not containing fibers.
<3>
The content of the fiber in the first layer is 10% by mass or more and 90% or less, preferably 20% by mass or more and 80% or less by mass, based on the total mass of the first layer. absorbent article.
<4>
The content of the water-absorbing polymer in the first layer is 20% by mass or more and 90% by mass or less, preferably 50% by mass or more and 80% by mass or less, relative to the total mass of the first layer, <2 > or the absorbent article according to <3>.
<5>
The content of fibers with respect to the total weight of the water-absorbing polymer layer is 10% by mass or less, preferably 5% by mass or less, and more preferably, the water-absorbing polymer layer does not contain fibers. 4>, the absorbent article according to any one of the above items.
<6>
The absorbent according to any one of <2> to <5> above, wherein the basis weight of the first layer is 50 m ² or more and 1000 g/m ² or less, preferably 100 g/m ² or more and 800 g/m ² or less. Goods.
<7>
The absorbent according to any one of <2> to <6> above, wherein the water-absorbing polymer layer has a basis weight of 5 m ² or more and 1000 g/m ² or less, preferably 20 g/m ² or more and 800 g/m ² or less. sexual goods.

<8>
The absorbent article according to any one of <2> to <7>, wherein the second layer has a higher water absorption rate by the vortex method of the water-absorbent polymer than the first layer.
<9>
The ratio of the water absorption speed of the water-absorbent polymer of the second layer by the vortex method to the water absorption speed of the water-absorbent polymer of the first layer by the vortex method is 1.1 or more and 6 or less, preferably 1.4 or more and 4 or less. The absorbent article according to <8> above.
<10>
The absorbent article according to <8> or <9> above, wherein the water absorption rate of the water-absorbent polymer of the first layer by a vortex method is 30 seconds or more and 120 seconds or less, preferably 40 seconds or more and 60 seconds or less.
<11>
Any one of <8> to <10> above, wherein the water absorption rate of the water-absorbent polymer of the second layer by a vortex method is 10 seconds or more and 40 seconds or less, preferably 20 seconds or more and 30 seconds or less. absorbent article.

<12>
The absorbent article according to any one of <2> to <11>, wherein the second layer has a smaller average particle size of the water-absorbing polymer than the first layer.
<13>
The ratio of the average particle size of the water-absorbing polymer of the first layer to the average particle size of the water-absorbing polymer of the second layer is 1.05 or more and 4 or less, preferably 1.3 or more and 3 or less, The absorbent article according to <12>.
<14>
The absorbent article according to <12> or <13> above, wherein the water-absorbing polymer of the first layer has an average particle size of 300 μm or more and 1000 μm or less, preferably 400 μm or more and 850 μm or less.
<15>
The absorbent article according to any one of <12> to <14> above, wherein the average particle size of the water-absorbing polymer of the second layer is 100 μm or more and 600 μm or less, preferably 200 μm or more and 500 μm or less.

<16>
The ratio of the liquid permeation speed under pressure of the water absorbent polymer of the first layer at 2.0 kPa to the liquid permeation speed of the water absorbent polymer of the second layer under pressure of 2.0 kPa is 2.8 or more, preferably 2. The absorbent article according to any one of the above <1> to <15>, which is 8 or more and 300 or less, more preferably 83 or more and 200 or less.
<17>
The above <16>, wherein the water-absorbent polymer of the first layer has a liquid permeation rate under pressure of 2.0 kPa of 30 mL/min or more and 1000 mL/min or less, preferably 50 mL/min or more and 400 mL/min or less. absorbent article.
<18>
<16>, wherein the water-absorbent polymer of the second layer has a liquid permeation rate under pressure of 2.0 kPa of 0.1 mL/min or more and 150 mL/min or less, preferably 2 mL/min or more and 100 mL/min or less; Or the absorbent article according to <17>.
<19>
Ratio of the lateral length of the first layer to the lateral length of the second layer in a cross-sectional view along the thickness direction and the lateral direction at the portion of the absorbent core where the laterally extending portion exists is 0.83 or less, preferably 0.25 or more and 0.83 or less, more preferably 0.4 or more and 0.58 or less, the absorbent article according to any one of the above <1> to <18> .
<20>
The absorbent article according to <19> above, wherein the laterally extending portion of the absorbent core has a lateral length of 10 mm or more and 50 mm or less, preferably 25 mm or more and 40 mm or less.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples.

[Examples 1 to 3, Comparative Examples 1 to 3]
Deployable disposable diapers having the same basic configuration as the diaper 1 shown in FIG. 1 were produced as examples and comparative examples. Each example and comparative example are constructed in the same manner except for the absorbent core. Details of main members in the disposable diapers of Examples and Comparative Examples are as follows.
- An air-through nonwoven fabric having a basis weight of 25 g/m ² was used as the surface sheet.
A polyethylene resin film (FL-KDJ100nN, manufactured by Taika Kogyo Co., Ltd.) with a basis weight of 37 g/m ² was used as the back sheet.
- As the absorbent core, a two-layer structure was used in which a first layer and a second layer disposed farther from the wearer's skin than the first layer were laminated in the thickness direction.
As the first layer, a laminated fiber type absorbent core containing bleached softwood kraft pulp (NBKP), which is a hydrophilic fiber, and water-absorbent polymer particles was used. The basis weight of the first layer was 100 g/m ² , the basis weight of the hydrophilic fibers in the first layer was 100 g/m ² , and the basis weight of the water-absorbing polymer in the first layer was 100 g/m ² .
As the second layer, a sheet-type absorbent core was used in which a water-absorbent polymer layer consisting of only water-absorbent polymer particles was interposed between two base sheets. A base paper having a basis weight of 16 g/m ² was used as the base sheet, and the two base sheets and the base sheet and the water-absorbent polymer were bonded together with a hot-melt adhesive. The basis weight of the water-absorbing polymer in the second layer was 100 g/m ² .

[Performance evaluation]
For the disposable diapers of each example and comparative example, the load pressure to the crotch and side leakage were measured and evaluated by the following methods. The results are shown in Table 1 below.

<Evaluation of load pressure to crotch: measurement of ring crush compression strength>
The compressive strength (ring crush compressive strength) of a cylindrical test piece cut out from the absorbent article to be measured is measured.
Specifically, from the absorbent article to be measured, a rectangular shape in plan view with a length of 250 mm in the vertical direction and a length of 160 mm in the horizontal direction, including the central portion of the absorbent article (the central portion of the crotch portion in the horizontal direction), is measured. A test piece is cut out along the entire direction. When the test piece includes an elastic member that constitutes a leak-proof cuff, leg gathers, or the like, the elastic member is cut to lose elasticity. A cylindrical test piece having a diameter of 73 mm is prepared by rolling the test piece in the longitudinal direction (longitudinal direction of the absorbent article) with the surface facing the skin (surface sheet 3 side) of the test piece inside. In the cylindrical test piece, the length in the circumferential direction of the overlapping portion between one end and the other end in the longitudinal direction of the test piece is set to 20 mm, and the overlapping portion is spaced apart in the axial direction of the test piece. The two portions are fixed using staples (for example, No. 10-1M needles manufactured by Max Co., Ltd.). The direction of the staples (needles) is parallel to the circumferential direction of the cylindrical test piece. The cylindrical test piece is set in a predetermined clearance of a Tensilon compression tester (“RTA-100” manufactured by Orientec Co., Ltd.), and the compression plate is moved at a speed of 300 mm / min to narrow the clearance. The test piece set in the clearance is compressed in its axial direction (lateral direction of the absorbent article). Compress the cylindrical test piece until the clearance becomes 20 mm from 170 mm before the start of compression, measure the load (N) at the time when the clearance reaches 20 mm, and use it as the ring crush compression strength of the test piece. . The clearance of 20 mm corresponds to the general crotch width of the wearer of the absorbent article. The measurement is performed 5 times for each type of measurement object, and the average value of the remaining 3 points is taken as the measured value, except for the values at the upper and lower points.
The smaller the numerical value of the ring crush compression strength, the lower the load pressure on the wearer's crotch (leg) when the absorbent article to be measured is worn, and the more comfortable it is to wear. More specifically, in descending order of evaluation, when the ring crush compressive strength is 15 N or less (highest evaluation), when the ring crush compressive strength exceeds 15 N and is 20 N or less, the ring crush compressive strength is 20 N. If it exceeds (minimum evaluation).

<Evaluation of side leakage: measurement of liquid absorption>
A region with a length of 10 mm in the vertical direction and a length of 10 mm in the horizontal direction is cut out from the crotch portion of the absorbent article to be measured (central portion in the longitudinal direction of the absorbent article in the unfolded and stretched state) over the entire thickness direction, and a test piece is obtained. and The test piece was placed on an acrylic plate inclined surface with an angle (angle on the acute angle side) of 10 degrees with the horizontal plane, and artificial urine (physiological saline) was applied to the center of the test piece at a rate of 5 g/sec. Inject 15 g of This artificial urine injection operation is repeated at intervals of 5 minutes until the artificial urine leaks from the test piece, that is, until lateral leakage occurs. When side leakage occurs, the injection of artificial urine is stopped and the weight of the test piece (weight after liquid absorption) is measured, and from the measured value, the weight of the test piece ( Subtract the weight before liquid absorption) to calculate the amount of liquid absorption.
The larger the numerical value of the liquid absorption amount, the more difficult the occurrence of lateral leakage and the higher the evaluation. More specifically, in descending order of evaluation, when the liquid absorption amount is 90 g or more (highest evaluation), when the liquid absorption amount is 80 g or more and less than 90 g, when the liquid absorption amount is 70 g or more and less than 80 g, the above When the amount of liquid absorption is less than 70 g (minimum evaluation).

As shown in Table 1, in the disposable diaper of each example, the second layer has a laterally extending part in the crotch portion, and the second layer has a water-absorbent polymer at 2.0 kPa compared to the first layer. Since the liquid permeation rate under pressure was low (the ratio A/B exceeded 1), the load pressure to the crotch was small and the lateral leakage prevention performance was excellent compared to each of the comparative examples that did not satisfy these requirements.

1 Disposable diaper (absorbent article)
2 Absorbent main body 3 Top sheet 4 Back sheet 5 Absorbent body 6 Absorbent core 7 First layer 8 Second layer 80 Water absorbent polymer layer 81 Base sheet 82 Lateral extension 9 Core wrap sheet P Water absorbent polymer X Vertical Direction Y Lateral direction A Abdominal part B Crotch part C Dorsal part

Claims (6)

A crotch portion having a longitudinal direction extending from the wearer's abdomen to the back side through the crotch portion and a lateral direction orthogonal to the longitudinal direction, and a crotch portion arranged in the crotch portion, and a wearer's body extending from the crotch portion. An absorbent article comprising an absorbent core that is divided into an abdominal portion arranged on the abdomen side and a dorsal portion arranged on the back side of the wearer from the crotch portion and that absorbs and retains excrement. hand,
The absorbent core has a laminated structure in which a first layer and a second layer arranged farther from the wearer's skin than the first layer are laminated in a thickness direction. The second layers each contain a particulate water-absorbing polymer,
The second layer has, at least in the crotch portion, a laterally extending portion extending outward in the lateral direction from a side edge along the longitudinal direction of the first layer,
In the absorbent article, the second layer has a lower liquid permeation rate under pressure of the water-absorbent polymer at 2.0 kPa than the first layer. The first layer has a fiber assembly containing hydrophilic fibers, and the water-absorbent polymer is present in inter-fiber voids of the fiber assembly,
2. The absorbent article according to claim 1, wherein said second layer comprises a water-absorbing polymer layer containing said water-absorbing polymer and not containing fibers. 3. The absorbent article according to claim 2, wherein said second layer has a higher rate of water absorption by the vortex method of said water-absorbent polymer than said first layer. 4. The absorbent article according to claim 2, wherein said second layer has a smaller average particle size of said water absorbent polymer than said first layer. The ratio of the liquid permeation speed under pressure of the water absorbent polymer of the first layer at 2.0 kPa to the liquid permeation speed of the water absorbent polymer of the second layer under pressure at 2.0 kPa is 2.8 or more. The absorbent article according to any one of claims 1-4. Ratio of the lateral length of the first layer to the lateral length of the second layer in a cross-sectional view along the thickness direction and the lateral direction at the portion of the absorbent core where the laterally extending portion exists is 0.83 or less, the absorbent article according to any one of claims 1 to 5.

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