CN112672721B

CN112672721B - Absorbent article

Info

Publication number: CN112672721B
Application number: CN201880097212.2A
Authority: CN
Inventors: 曽我部瑶介; 大村夏美; 黑田贤一郎; 野田祐树
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2018-09-10
Filing date: 2018-09-11
Publication date: 2023-04-04
Anticipated expiration: 2038-09-11
Also published as: CN112672721A; JP2020039570A; JP6445732B1; KR102557595B1; WO2020053966A1; TW202010888A; TWI816817B; KR20210041050A

Abstract

In the absorptive article (1), the absorption performance can be improved while the skin touch of the top sheet (2) is improved. In an absorbent article (1), a topsheet (2) includes: a 1 st fiber layer (2 a) containing water-retentive fibers; and a 2 nd fiber layer (2 b) adjacent to the non-skin side of the 1 st fiber layer (2 a) and containing a hydrophobic fiber and a water-retentive fiber. The skin-side surface of the 1 st fiber layer (2 a) constitutes the skin-side surface of the topsheet (2). The proportion of the water-retentive fibers in the fibers constituting the 1 st fiber layer (2 a) is greater than the proportion of the water-retentive fibers in the fibers constituting the 2 nd fiber layer (2 b). The average fiber length of the water-retentive fibers of the 2 nd fiber layer (2 b) is shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer (2 a).

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article.

Background

As a topsheet of an absorbent article, a sheet containing water-retentive fibers such as cotton fibers which absorb and retain water is known. For example, patent document 1 discloses a fiber sheet containing cotton fibers as a surface sheet. The fiber sheet comprises a cotton fiber layer and a nonwoven fabric of synthetic fibers, and is formed in a state in which a part of the cotton fiber layer is inserted into the nonwoven fabric.

In general, a water-retentive fiber such as a cotton fiber has a good skin touch and is therefore suitable for use in underwear and the like that come into contact with the skin. However, since cotton fibers have high water retentivity, when a sheet containing cotton fibers is used as a topsheet of an absorbent article, the topsheet may absorb and retain liquid excrement (liquid excrement) excreted from a wearer and maintain a moist state. In this case, the wearer may feel discomfort because of the continuous contact with the wet topsheet. That is, when a sheet containing cotton fibers is used for the surface sheet, there is a problem that the dryness is low.

According to the description of patent document 1, the fiber sheet containing cotton fibers disclosed in patent document 1 has the following characteristics. In the fiber sheet, the cotton fiber layer penetrates into the nonwoven fabric in the thickness direction, and therefore the amount of fibers gradually increases from the cotton fiber layer toward the center portion of the fiber sheet in the thickness direction, that is, the inter-fiber distance gradually decreases. As a result, the capillary force gradually increases from the cotton fiber layer toward the center portion of the fiber sheet in the thickness direction, and the drawing-in property of the liquid from the cotton fiber layer into the sheet increases. The surface of the fiber sheet can be dried more efficiently.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2004-324038

Disclosure of Invention

Problems to be solved by the invention

However, the fiber sheet containing cotton fibers of patent document 1 has the following problems. The synthetic fiber layer of the fiber sheet on the opposite side of the cotton fiber layer across the center in the thickness direction is a synthetic fiber-only layer. Therefore, the fiber amount gradually decreases from the center portion in the thickness direction of the fiber sheet toward the layer of the synthetic fibers, that is, the inter-fiber distance gradually increases. As a result, the capillary force gradually decreases from the central portion in the thickness direction of the fiber sheet toward the layer of synthetic fibers. In this case, the fiber sheet can introduce the liquid absorbed from the cotton fiber layer side into the central portion in the thickness direction of the fiber sheet, but it is difficult to transfer the liquid to the synthetic fiber layer side. Therefore, when the fibrous sheet is used as a topsheet of an absorbent article, the topsheet can draw liquid excrement excreted from the wearer from the cotton fiber layer to the central portion in the thickness direction, but it is difficult to transfer the excrement from the central portion in the thickness direction to the synthetic fiber layer. That is, the liquid excrement is less likely to migrate from the topsheet to the absorbent body, and the absorbent performance of the absorbent article may be deteriorated, for example, the absorption rate may be decreased or the absorption amount may be decreased.

The purpose of the present invention is to provide an absorbent article that can improve the absorption performance while improving the tactile sensation of the topsheet.

Means for solving the problems

The absorbent article of the present invention is as follows. (1) An absorbent article comprising a front sheet, a back sheet, and an absorber positioned between the front sheet and the back sheet, wherein the front sheet comprises: a 1 st fiber layer containing water-retentive fibers; and 2 nd fibrous layer, its with the non-skin side of 1 st fibrous layer is adjacent, contains hydrophobic fiber and water-retaining fibre, the surface of the skin side of 1 st fibrous layer constitutes the surface of the skin side of surface piece, the surface of the non-skin side of 2 nd fibrous layer constitutes the surface of the non-skin side of surface piece constitutes in the fibre of 1 st fibrous layer the proportion of water-retaining fibre is greater than the constitution in the fibre of 2 nd fibrous layer the fibrous proportion of water-retaining, 2 nd fibrous layer the fibrous average fiber length of water-retaining compares the fibrous average fiber length of water-retaining of 1 st fibrous layer is short.

In the present absorbent article, the ratio of the water-retentive fibers in the 1 st fibrous layer located on the skin side of the topsheet is relatively high, and therefore the skin feel of the topsheet can be improved. Further, since the average fiber length of the water-retentive fibers contained in the 1 st fiber layer is relatively long, it is possible to suppress the occurrence of fluffing due to insufficient interlacing of the fibers caused by an excessively short average fiber length, and to suppress a decrease in the skin feel of the surface sheet.

At this time, since the average fiber length of the water-retentive fibers contained in the 2 nd fibrous layer is shorter than the average fiber length of the water-retentive fibers contained in the 1 st fibrous layer, the fibers constituting the 2 nd fibrous layer can be brought closer to each other. Therefore, the average distance between fibers of the 2 nd fiber layer can be made shorter than the average distance between fibers of the 1 st fiber layer, so that the capillary phenomenon can be more strongly generated in the 2 nd fiber layer, and the liquid excrement excreted to the skin-side surface of the 1 st fiber layer can be quickly drawn into the 2 nd fiber layer. In addition, the liquid excrement introduced into the 2 nd fiber layer can be rapidly transferred to the absorbent body through the 2 nd fiber layer by the hydrophobic fibers.

In this case, in the 1 st fiber layer, the liquid excrement can be taken into the 2 nd fiber layer while being spread over a wide range in the planar direction by the water-retentive fibers having a relatively long average fiber length. This makes it possible to absorb liquid excreta that spreads over a wide range in the planar direction in the topsheet using a region of the absorbent body that is large in the planar direction, and therefore, the absorption performance can be improved.

This can improve the skin feel of the topsheet and improve the absorption performance.

In the absorbent article of the present invention, there may be (2) an absorbent article including a front sheet, a back sheet, and an absorbent body located between the front sheet and the back sheet, wherein the front sheet includes: a 1 st fiber layer containing water-retentive fibers; and the 2 nd fibrous layer, its with the non-skin side of the 1 st fibrous layer is adjacent, contains hydrophobic fiber and water-retaining fibre, the surface of the skin side of the 1 st fibrous layer constitutes the surface of the skin side of surface piece, the surface of the non-skin side of the 2 nd fibrous layer constitutes the surface of the non-skin side of surface piece constitutes in the fibre of the 1 st fibrous layer the fibrous proportion of water-retaining is greater than and constitutes in the fibre of the 2 nd fibrous layer the fibrous proportion of water-retaining, the fibre density of the 1 st fibrous layer is less than the fibre density of the 2 nd fibrous layer. Here, the fiber density is a density of the number of fibers.

In the present absorbent article, the ratio of the water-retentive fibers in the 1 st fibrous layer positioned on the skin side of the topsheet is relatively high, and therefore the skin feel of the topsheet can be improved.

In this case, since the fiber density of the 2 nd fiber layer is higher than that of the 1 st fiber layer, the fibers constituting the 2 nd fiber layer can be brought closer to each other. Therefore, the average distance between the fibers of the 2 nd fiber layer can be made shorter than the average distance between the fibers of the 1 st fiber layer, so that the capillary phenomenon can be more strongly generated in the 2 nd fiber layer, and the liquid excrement excreted to the skin-side surface of the 1 st fiber layer can be quickly introduced into the 2 nd fiber layer. In addition, the liquid excrement introduced into the 2 nd fiber layer can be rapidly transferred to the absorbent body through the 2 nd fiber layer by the hydrophobic fibers.

In this case, in the 1 st fiber layer, the liquid excrement can be taken into the 2 nd fiber layer while being spread over a wide range in the planar direction by the water-retentive fibers. This allows the liquid excrement spreading over a wide range in the planar direction in the topsheet to be absorbed by the region of the absorbent body that is large in the planar direction, and therefore, the absorption performance can be improved.

An absorbent article of the present invention may be (3) the absorbent article according to the above (2), further comprising an auxiliary sheet having a fiber density higher than that of the 2 nd fiber layer between the topsheet and the absorbent body.

In the present absorbent article, since the auxiliary sheet having a fiber density higher than that of the 2 nd fiber layer is further included, the liquid excrement introduced into the 2 nd fiber layer can be stably transferred to the auxiliary sheet by utilizing the capillary phenomenon. This makes it possible to transfer the liquid excrement from the topsheet to the absorbent body more stably via the auxiliary sheet, and thus to improve the skin feel of the topsheet and the absorption performance.

The absorbent article of the present invention may be (4) the absorbent article according to any one of (1) to (3), wherein the hydrophobic fibers contained in the 2 nd fiber layer include heat-fusible fibers heat-fused to each other.

In the present absorbent article, the heat-fusible fibers are heat-fused to each other in the 2 nd fiber layer, whereby the shape of the 2 nd fiber layer can be stably maintained. Therefore, even if the average fiber length of the water-retentive fibers contained in the 2 nd fiber layer is relatively short, the water-retentive fibers can be stably held between the hydrophobic fibers without being biased. This enables the liquid excrement introduced into the 2 nd fiber layer to be stably transferred to the absorbent body without being biased, and the absorption performance can be improved.

An absorbent article of the present invention may be (5) the absorbent article according to the item (4), wherein at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed on a surface of the 1 st fiber layer on the skin side.

In the present absorbent article, since a part of the heat-fusible fibers of the 2 nd fiber layer is present in the 1 st fiber layer so as to be exposed on the surface of the 1 st fiber layer, the water-retentive fibers of the 1 st fiber layer can be stably held between the heat-fusible fibers. Thus, even if the average distance between the fibers of the 1 st fiber layer is relatively long and the strength of the 1 st fiber layer is relatively weak, collapse can be suppressed. Moreover, fuzz can also be suppressed by holding the water-retentive fibers of the 1 st fiber layer between the heat-fusible fibers. This makes it possible to improve the texture of the 1 st fiber layer. Further, since a part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer is present in the 1 st fiber layer, the transfer of the liquid excrement from the 1 st fiber layer to the 2 nd fiber layer through the heat-fusible fibers can be promoted. This makes it possible to stably transfer the liquid excrement to the absorbent body.

The absorbent article of the present invention may be (6) the absorbent article according to (4) or (5), wherein the absorbent article has a compressed portion obtained by compressing the topsheet and the absorbent body in a thickness direction of the absorbent article, and at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed on a surface inside the compressed portion.

In the absorbent article of the present invention, since a part of the heat-fusible fibers of the 2 nd fiber layer is present in the 1 st fiber layer so as to be exposed on the inner surface of the compressed portion, the water-retentive fibers of the 1 st fiber layer in the compressed portion can be stably held between the heat-fusible fibers. Thus, even if the strength of the 1 st fiber layer in the compressed portion is relatively weak, collapse and fuzz can be suppressed, and the skin touch of the 1 st fiber layer in the compressed portion can be made better. Further, since a part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer is present in the 1 st fiber layer in the compressed part, the transfer of the liquid excrement from the 1 st fiber layer in the compressed part to the 2 nd fiber layer via the heat-fusible fibers can be promoted. This makes it possible to transfer the liquid excrement more stably to the absorbent body.

The absorbent article of the present invention may be (7) the absorbent article according to the above (6), wherein the compressing portion includes: a low-density portion having a shallow depth in the thickness direction of the absorbent article; and a high-density portion having a deep depth in the thickness direction of the absorbent article, wherein at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed on the surface of the low-density portion.

In the absorbent article of the present invention, since a part of the heat-fusible fibers of the 2 nd fiber layer is present in the 1 st fiber layer so as to be exposed to the surface of the low-density portion, the water-retentive fibers of the 1 st fiber layer in the low-density portion can be stably held between the heat-fusible fibers. Thus, even if the strength of the 1 st fiber layer in the low-density portion is relatively weak, collapse and fuzz can be suppressed, and the skin touch of the 1 st fiber layer in the low-density portion can be made better. Further, since a part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer is present in the 1 st fiber layer in the low-density portion, the transfer of the liquid excrement from the 1 st fiber layer in the low-density portion to the 2 nd fiber layer via the heat-fusible fibers can be promoted. This makes it possible to transfer the liquid excrement to the absorbent body more stably.

The absorbent article of the present invention may be (8) the absorbent article according to any one of (1) to (7), wherein the top sheet has: a plurality of protrusions extending in the longitudinal direction of the absorbent article and located at positions spaced apart in the width direction of the absorbent article; and a plurality of concave portions extending in the longitudinal direction of the absorbent article and located between the convex portions adjacent to each other, wherein, in the topsheet, S1 < S3 < S2 is obtained when the fiber density at the top of the convex portions is S1, the fiber density at the bottom of the concave portions is S2, and the fiber density in the region between the top of the convex portions and the bottom of the concave portions is S3.

In the absorbent article according to claim 8, in the topsheet, the capillary phenomenon acts from the top of the convex portion having a low fiber density toward the bottom of the concave portion having a high fiber density via the region between the top of the convex portion having a medium fiber density and the bottom of the concave portion. Therefore, the liquid excrement excreted on the surface of the topsheet closest to the skin (the top of the convex portion or the vicinity thereof) can be more easily drawn into the bottom of the concave portion located in the vicinity of the surface of the topsheet closest to the non-skin. This makes it possible to transfer the liquid excrement from the skin-side surface of the topsheet to the absorbent body more stably through the non-skin-side surface of the topsheet. Further, the liquid excrement temporarily absorbed can be made less likely to be rewet by the gradient of the fiber density. Further, since the fiber density of the convex portions is low, the wearer can feel softness. Therefore, the top sheet can have a good tactile sensation to the skin and improved absorption performance.

An absorbent article of the present invention may be (9) the absorbent article according to the above (8), wherein the top sheet has a plurality of depressions in each of the plurality of depressions, the depressions compressing the 1 st fiber layer and the 2 nd fiber layer in a thickness direction of the absorbent article.

In the present absorbent article, the 1 st fiber layer and the 2 nd fiber layer are compressed and fixed to each other in the plurality of depressions, and therefore the water-retentive fibers of the 1 st fiber layer are compressed. This can suppress fluffing of the water-retentive fibers and can maintain the skin feel of the top sheet satisfactorily.

The absorbent article of the present invention may be (10) the absorbent article according to any one of the above (1) to (9), wherein the average fiber length of the hydrophobic fibers of the 2 nd fiber layer is longer than the average fiber length of the water-retentive fibers of the 1 st fiber layer and the 2 nd fiber layer.

In the present absorbent article, the average fiber length of the hydrophobic fibers of the 2 nd fiber layer is longer than the average fiber length of the water-retentive fibers of the 1 st fiber layer and the 2 nd fiber layer. Therefore, at least a part of the hydrophobic fibers of the 2 nd fiber layer can reach the inside of the 1 st fiber layer. This makes it possible to more easily transfer the liquid excrement in the 1 st fiber layer to the 2 nd fiber layer and to more easily transfer the liquid excrement transferred to the 2 nd fiber layer to the absorbent body.

The absorbent article of the present invention may be (11) the absorbent article according to any one of (1) to (10), wherein the water-retentive fibers contained in the top sheet are cellulosic fibers, the absorbent body contains cellulosic fibers (excluding pulp fibers), and a part of the cellulosic fibers contained in the top sheet is in contact with the cellulosic fibers contained in the absorbent body.

In the absorbent article of the present invention, the cellulose-based fibers having high liquid diffusibility are communicated from the 1 st fiber layer of the topsheet to the absorbent body through the 2 nd fiber layer. Therefore, by utilizing the liquid diffusion of the liquid excrement by the cellulose fiber, the liquid excrement can be directly diffused from the topsheet to the absorbent body. Thereby enabling the absorption performance to be improved.

The absorbent article of the present invention may be (12) the absorbent article according to any one of (1) to (11), wherein the fibers constituting the top sheet at both ends in the width direction of the top sheet are oriented in the longitudinal direction of the top sheet, compared to the fibers constituting the top sheet at the center in the width direction of the top sheet.

In the absorbent article of the present invention, the fibers of the top sheet are randomly oriented in the central portion, whereby the liquid excrement can be spread concentrically without being lost, and the fibers are oriented in the longitudinal direction in both end portions, whereby the liquid excrement reaching both end portions can be spread in the longitudinal direction. That is, the absorbent article can be used as a whole, thereby improving the absorption performance. In addition, since the number of fibers exposed from the edge is small at both ends of the topsheet, friction against the skin is reduced, and a decrease in the tactile sensation of the skin can be suppressed.

The absorbent article of the present invention may be (13) the absorbent article according to any one of (1) to (12) above, wherein the water-retentive fibers contained in the top sheet are cotton.

In the absorbent article of the present invention, since the water-retentive fibers are cotton, the skin feel of the topsheet can be further improved, and the absorption performance can be further maintained or improved.

The absorbent article of the present invention may be (14) the absorbent article according to any one of (1) to (13), further comprising an auxiliary sheet positioned between the top sheet and the absorbent body, wherein the dimension of the top sheet in the width direction is smaller than the dimension of the auxiliary sheet in the width direction.

When the edges of the surface sheet containing a large amount of water-retentive fibers are rubbed, the water-retentive fibers are easily separated from the edges and fall off. Therefore, in the present absorbent article, the dimension in the width direction of the auxiliary sheet is larger than the dimension in the width direction of the surface sheet containing a large amount of water-retentive fibers. That is, the auxiliary sheet has a pair of projecting portions formed at positions outside both end edges in the width direction of the front sheet in a plan view. Therefore, the force applied from the wearer's thighs to the absorbent article can be received by the pair of extension portions at the both ends in the width direction of the auxiliary sheet, and the both end edges in the width direction of the topsheet and the thighs can be made less likely to rub against each other. This can prevent the water-retentive fibers from being separated and detached from the widthwise opposite end edges of the top sheet by rubbing the widthwise opposite end edges of the top sheet, thereby preventing a decrease in the tactile sensation of the skin.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an absorbent article can be provided which can improve the absorption performance while improving the tactile sensation of the topsheet.

Drawings

Fig. 1 is a plan view showing a configuration example of an absorbent article according to the embodiment.

Fig. 2 is a sectional view taken along line II-II of fig. 1.

Fig. 3 is a plan view and a sectional view showing a configuration example of the front sheet of the embodiment.

Fig. 4 is a schematic diagram showing a configuration example of the apparatus for manufacturing an absorbent article according to the embodiment.

Fig. 5 is a sectional view illustrating a method of manufacturing an absorbent article according to the embodiment.

Detailed Description

The absorbent article according to the embodiment will be described by taking a sanitary napkin as an example. However, the type and use of the absorbent article of the present invention are not limited to this example, and the present invention can be applied to other absorbent articles as long as the type and use do not depart from the scope of the subject matter of the present invention. Examples of other absorbent articles include pantiliners, light incontinence pads, and disposable diapers.

(embodiment 1)

Fig. 1 to 2 are views showing a configuration example of a sanitary napkin 1 according to an embodiment. Fig. 1 is a plan view showing a state where a sanitary napkin 1 is unfolded, fig. 2 (a) is a cross-sectional view taken along the line II-II in fig. 1, and fig. 2 (b) is a partially enlarged cross-sectional view of fig. 2 (a). The sanitary napkin 1 of the present embodiment has a longitudinal direction L, a width direction W, and a thickness direction T that are orthogonal to each other. In the sanitary napkin 1 shown in fig. 1, the upper side and the lower side in the drawing are respectively defined as the front side and the rear side in the longitudinal direction L, the left side and the right side are respectively defined as the left side and the right side in the width direction W, and the front side and the back side with respect to the paper surface are respectively defined as the upper side and the lower side in the thickness direction T. The sanitary napkin 1 has a longitudinal centerline C extending in the longitudinal direction L through the center in the width direction W _L (imaginary line) and a width-direction center line C passing through the center of the longitudinal direction L and extending in the width direction W _W (phantom line). Will be oriented toward the longitudinal center line C _L Is set as the inward direction and the inward side of the width direction W, and is away from the center line C in the length direction _L Is set to the width direction and one side is set to the width directionThe outward direction and the outer side of W. On the other hand, will be oriented toward the width direction center line C _W Is set to be inward and inward of the longitudinal direction L and is away from the center line C in the width direction _W Is set as the outward direction and the outer side of the length direction L, respectively. The angle of view of the sanitary napkin 1 placed on a plane including the longitudinal direction L and the width direction W as viewed from above in the thickness direction T is referred to as "top view", and the shape grasped in the top view is referred to as "top view shape". An arbitrary direction in a plane including the longitudinal direction L and the width direction W is referred to as a "plane direction". When a wearer who is positioned above wears the sanitary napkin 1, the side relatively close to the skin surface of the wearer and the side far from the skin surface of the wearer in the thickness direction T are referred to as the "skin side" and the "non-skin side". The above definitions are also common to the respective materials of the sanitary napkin 1.

In the present embodiment, the sanitary napkin 1 (excluding the wing portions) has a substantially rectangular shape that is long in the longitudinal direction L and short in the width direction W in a plan view, and has a shape in which both end edges in the longitudinal direction L are substantially semicircular. However, the shape is not particularly limited as long as it is long in the longitudinal direction L and short in the width direction W, and examples thereof include a rounded rectangle, an ellipse, an hourglass shape, and shapes similar to these shapes. The sanitary napkin 1 includes flaps 9 extending outward in the width direction W from a substantially rectangular portion, and the flaps 9 have a substantially trapezoidal shape. However, the shape of the wing 9 may be, for example, a semicircular shape or a semi-elliptical shape.

In the present embodiment, the sanitary napkin 1 includes a front sheet 2 constituting the skin-side front surface of the sanitary napkin 1, a back sheet 3 constituting the non-skin-side front surface of the sanitary napkin 1, and an absorbent body 4 disposed between the front sheet 2 and the back sheet 3. In the present embodiment, the sanitary napkin 1 further includes an auxiliary sheet 5 and a pair of

side sheets

6 and 6. The auxiliary sheet 5 is disposed so as to overlap the non-skin side of the top sheet 2. The pair of

side pieces

6, 6 are joined so that the inner ends in the width direction W overlap with the respective ends of the both ends in the width direction W on the non-skin side of the auxiliary piece 5, and protrude outward in the width direction W. Therefore, in the present embodiment, the absorber 4 is positioned between the front sheet 2, the auxiliary sheet 5, and the pair of

side sheets

6 and 6, and the back sheet 3. However, an exterior sheet may be provided on the non-skin side of the back sheet 3.

The top sheet 2 is a liquid-permeable sheet and includes a 1 st fiber layer 2a and a 2 nd fiber layer 2b. The skin-side surface of the 1 st fiber layer 2a constitutes the skin-side surface of the surface sheet 2. The 2 nd fibrous layer 2b is adjacent to the non-skin side of the 1 st fibrous layer 2a. In the present embodiment, the non-skin side surface of the 2 nd fibrous layer 2b constitutes the non-skin side surface of the topsheet 2, and thus the topsheet 2 has a two-layer structure. However, the 2 nd fibrous layer 2b may contain one or more fibrous layers on the non-skin side, and thus the topsheet 2 as a whole may have a three-layer or multi-layer structure.

The 1 st fiber layer 2a contains water-retentive fibers.

The water-retentive fiber is not particularly limited as long as it has a property of absorbing and retaining water (water retentivity). Examples of the water-retentive fibers include cellulosic fibers. The cellulose-based fiber is not particularly limited as long as it is a fiber containing cellulose, and examples thereof include natural cellulose fibers, regenerated cellulose fibers, purified cellulose fibers, and semi-synthetic cellulose fibers. Examples of the natural cellulose fiber include plant fibers, such as seed fibers (e.g., cotton), bast fibers (e.g., hemp), vein fibers (e.g., manila hemp), and fruit fibers (e.g., coconut). Examples of cotton include upland cotton (exemplified by upland cotton), sea island cotton (barbadense), tree cotton (arboreum), and grass cotton (herbaceum). Cotton may be Organic Cotton or Pre Organic Cotton (trademark). The Organic Cotton is Cotton certified with GOTS (Global Organic Textile Standard). Examples of the regenerated cellulose fibers include rayon, for example, viscose rayon obtained from viscose, high wet modulus viscose, and cuprammonium rayon (also referred to as "cupro") obtained from a cuprammonium salt solution of cellulose. Examples of the refined cellulose fibers include lyocell, specifically, a material obtained by dissolving pulp in an aqueous solution of N-methylmorpholine-N-oxide to prepare a dope (dope) and extruding the dope into a diluted solution of N-methylmorpholine-N-oxide to prepare fibers. Purified cellulose is commercially available, for example, as Tencel (trademark). Examples of the semi-synthetic cellulose fibers include semi-synthetic cellulose, such as acetate fibers, and fibers such as triacetate and diacetate. Among them, natural cellulose fibers are preferable, cotton is more preferable, and upland cotton is further preferable, from the viewpoint of water retentivity and skin touch. In the present embodiment, the water-retentive fiber is upland cotton (hereinafter, also simply referred to as "cotton").

The 2 nd fiber layer 2b contains hydrophobic fibers and water-retentive fibers.

The hydrophobic fiber is not particularly limited as long as it is a fiber having hydrophobicity. Examples of the hydrophobic fibers include thermoplastic resin fibers. The thermoplastic resin fiber is not particularly limited as long as it contains a thermoplastic resin. Examples of the thermoplastic resin include known resins such as olefin resins including Polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA), polyester resins including polyethylene terephthalate (PET) and polylactic acid (PLA), and polyamide resins including 6-nylon, and these resins may be used alone or in combination of two or more. The structure of the fiber made of such a thermoplastic resin is not particularly limited, and examples thereof include composite fibers such as sheath-core fibers, side-by-side fibers, and sea-island fibers; hollow-type fibers; flat, Y-shaped, C-shaped and other special-shaped section fibers; a latent crimp or crimp-apparent stereocrimped fiber; fibers having these structures may be used alone or in combination of two or more types of fibers, such as split fibers that are split by physical load such as water flow, heat, embossing, and the like. In the present embodiment, the hydrophobic fiber is a PET/PE sheath-core composite fiber. The water-retentive fibers are the same as the water-retentive fibers of the 1 st fibrous layer 2a. The term "hydrophobicity" refers to a property of being difficult to be dissolved in water or to retain water, and means, for example, that a contact angle with ion-exchanged water (for example, a specific resistance value of 10 M.OMEGA.cm) is about 80 to 100 degrees.

In the 1 st fiber layer 2a and the 2 nd fiber layer 2b, the proportion of the water-retentive fibers in the fibers constituting the 1 st fiber layer 2a is larger than the proportion of the water-retentive fibers in the fibers constituting the 2 nd fiber layer 2b. This makes it possible to improve the tactile sensation of the top sheet 2. Further, in the 1 st fiber layer 2a and the 2 nd fiber layer 2b, the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b is shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a. This makes it possible to draw liquid excrement strongly by bringing at least the fibers constituting the 2 nd fiber layer 2b closer to each other, that is, shortening the distance between the fibers, and thus strongly generating a capillary phenomenon. Specifically, for example, the following is shown.

From the viewpoint of improving the skin feel of the top sheet 2, the proportion of the water-retentive fibers in the fibers constituting the 1 st fibrous layer 2a is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, and still more preferably 90 to 100 mass%. By setting the amount to 70 mass% or more, the wearer can easily recognize the 1 st fiber layer 2a as a water-retentive fiber, and thus good comfort can be ensured. The fibers other than the water-retentive fibers among the fibers constituting the 1 st fiber layer 2a are not particularly limited as long as they can form a liquid-permeable layer, and examples thereof include thermoplastic resin fibers. In the present embodiment, the proportion of the water-retentive fibers is 100 mass%.

The fineness of the water-retentive fibers in the 1 st fiber layer 2a is not particularly limited, and examples thereof include 0.8dtex to 15dtex. The water-retentive fibers of the 1 st fiber layer 2a have a fiber length of, for example, 10 to 80mm. In the case where the fiber length is less than 10mm, the fiber length is too short, and the fibers are difficult to interlace with each other, and sufficient strength may not be obtained. When the fiber length is greater than 80mm, some of the fibers may protrude in the width direction W and stretch from the edge of the wearer's thigh to the edge of the other thigh, and in this case, liquid excrement adhering to the center portion in the width direction W of the sanitary napkin 1 may diffuse to both thighs due to the liquid diffusion effect of the water-retentive fibers, and may give a sense of discomfort to the wearer. The fiber length is preferably 15mm to 60mm, more preferably 20mm to 40mm. In contrast, the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a is, for example, 15 to 50mm, more preferably 20 to 45mm, and still more preferably 25 to 40mm.

In addition, the latitude, fiber length, and average fiber length of the fibers other than the water-retentive fibers in the 1 st fibrous layer 2a are preferably on the same level (within a range of 0.5 to 2 times) as those of the water-retentive fibers, from the viewpoint of not adversely affecting the skin touch of the water-retentive fibers. However, in the present embodiment, fibers other than the water-retentive fibers are not used.

The ratio of the water-retentive fibers in the fibers constituting the 2 nd fiber layer 2b is not particularly limited as long as it is smaller than the ratio of the water-retentive fibers in the 1 st fiber layer 2a. The proportion of the water-retentive fibers is, for example, 50 to 90 mass%. When the proportion of the water-retentive fibers is less than 50 mass%, the touch comfort in a state where pressure is applied in the thickness direction may be reduced. When the proportion of the water-retentive fibers is greater than 90% by mass, the effect of preventing fuzz formation by the hydrophobic fibers may be reduced. The proportion of the water-retentive fibers is preferably 60 to 85 mass%, more preferably 70 to 80 mass%. In contrast, the proportion of the hydrophobic fibers in the 2 nd fiber layer 2b is, for example, 10 to 50 mass%, preferably 15 to 40 mass%, and more preferably 20 to 30 mass%. The 2 nd fiber layer 2b may contain the 3 rd fibers in addition to the water-retentive fibers and the hydrophobic fibers.

The fineness of the water-retentive fibers in the 2 nd fiber layer 2b is not particularly limited, and examples thereof include 0.8dtex to 15dtex. The fiber length of the water-retentive fibers in the 2 nd fiber layer 2b is not particularly limited as long as the average fiber length is shorter than the average fiber length of the water-retentive fibers in the 1 st fiber layer 2a, and examples thereof include 3mm to 40mm. In the case where the fiber length is less than 3mm, the fiber length is too short, and the fibers are difficult to be entangled with each other, failing to obtain sufficient strength. When the fiber length is more than 40mm, the degree of freedom of the dynamic state of the fibers in the web state in the production process of the 2 nd fiber layer 2b is low, and the water-retentive fibers cannot enter the gaps between the hydrophobic fibers, and as a result, it is difficult to shorten the distance between the fibers in the 2 nd fiber layer 2b, and it is difficult to increase the fiber density. The water-retentive fibers of the 2 nd fiber layer 2b preferably have a fiber length of 5 to 35mm, more preferably 10 to 35mm. In contrast, the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b is, for example, 5 to 30mm, preferably 10 to 25mm, and more preferably 15 to 20mm.

Further, a mixed water-retentive fiber in which the water-retentive fiber having a fiber length within the above range is mixed with at least two types of water-retentive fibers, i.e., a water-retentive fiber having a long fiber length and a water-retentive fiber having a short fiber length, may be used. As an example thereof, the water-retentive fiber having a long fiber length can be set to a fiber length of, for example, 15mm to 40mm (preferably 20mm to 35 mm), and the water-retentive fiber having a short fiber length can be set to a fiber length of, for example, 3mm to 25mm (preferably 5mm to 20 mm). In this case, the water retentivity and the texture of the 2 nd fiber layer 2b can be improved by the water retentivity fibers having a long fiber length, and the distance between the fibers of the 2 nd fiber layer 2b can be shortened by the water retentivity fibers having a short fiber length.

The latitude of the hydrophobic fibers of the 2 nd fiber layer 2b is not particularly limited, and examples thereof include 1.1dtex to 8.8dtex. However, from the viewpoint of easiness of entanglement of the hydrophobic fibers of the 2 nd fiber layer 2b and the water-retentive fibers as main fibers of the 1 st fiber layer 2a, that is, easiness of transfer of liquid excrement from the 1 st fiber layer 2a, and peeling prevention property of preventing peeling between the 1 st fiber layer 2a and the 2 nd fiber layer 2b, it is preferable that the latitude of the hydrophobic fibers of the 2 nd fiber layer 2b is smaller than the fineness of the water-retentive fibers of the 1 st fiber layer 2a (smaller fiber diameter).

The fiber length of the hydrophobic fibers in the 2 nd fiber layer 2b is not particularly limited, and examples thereof include 10mm to 80mm. However, from the viewpoint of easiness of inter-interlacing of the hydrophobic fibers of the 2 nd fiber layer 2b and the water-retentive fibers which are main fibers of the 1 st fiber layer 2a, that is, easiness of transfer of liquid excrement from the 1 st fiber layer 2a, and peeling prevention property of preventing peeling between the 1 st fiber layer 2a and the 2 nd fiber layer 2b, it is preferable that the fiber length of the hydrophobic fibers of the 2 nd fiber layer 2b is longer than the fiber lengths of the water-retentive fibers of the 1 st fiber layer 2a and the 2 nd fiber layer 2b. In contrast, the average fiber length of the hydrophobic fibers in the 2 nd fiber layer 2b is, for example, 15 to 50mm.

The thickness of each of the 1 st fiber layer 2a and the 2 nd fiber layer 2b is not particularly limited, and may be, for example, 0.05mm to 4mm, preferably 0.1mm to 3mm, and more preferably 0.2mm to 2mm. However, from the viewpoint of making the 1 st fiber layer 2a feel good to the skin and suppressing rewet to the skin of the wearer, it is preferable that the thickness of the 1 st fiber layer 2a is relatively thick and the thickness of the 2 nd fiber layer 2b is relatively thin. The thickness of the top sheet 2 is not particularly limited, and may be, for example, 0.1mm to 5mm, preferably 0.4mm to 4mm, and more preferably 0.8mm to 3mm.

Here, the ratio of the types of fibers in a sheet such as a fiber layer is measured as follows.

That is, the ratio of the kind of the fiber is measured by coloring the water-retentive fiber and the hydrophobic fiber with different colors, respectively. (1) the surface sheet 2 was cut into a size of 70mm X70 mm to prepare a sample. (2) By coloring with a reagent KayastainQ (カヤステイン Q) (color dyeing, ltd.), only the water-retentive fibers were dyed blue and only the hydrophobic fibers were dyed yellow. (3) The ratio of blue to yellow observed from the skin side (the 1 st fiber layer 2 a) of the sample was measured in a range of 50mm × 50mm using a digital microscope VHX-100 manufactured by kynz co, ltd, as the ratio of the types of fibers in the 1 st fiber layer 2a. On the other hand, the ratio of blue to yellow when viewed from the non-skin surface (2 nd fibrous layer 2 b) was measured in a range of 50mm × 50mm as the ratio of the types of fibers in the 2 nd fibrous layer 2b.

Further, the distance between fibers in a sheet such as a fiber layer was measured according to the following measurement method. (1) the surface sheet 2 was cut into a size of 10 mm. Times.10 mm to prepare a sample. (2) Images were taken from the front surface (the 1 st fiber layer 2 a) and the back surface (the 2 nd fiber layer 2 b) of the front sheet 2 at a magnification of 200 times and a measurement area of 1300 μm in the vertical direction × 1735 μm in the horizontal direction using a digital microscope VHX-100 (lens VH-Z20R + variable lighting fixture VH-K20) manufactured by kynski co. In this case, a total of five images are taken at a depth of 20 μm for each of the front and back surfaces in the range of 0 μm to 100 μm. (3) The area of the portion where no fiber is present is determined from each of the obtained images. At this time, the presence or absence of a fiber in each pixel is determined based on whether the luminance in each pixel in each obtained image is lower or higher than a predetermined luminance (threshold value), and the presence or absence of a fiber in the imaging region in each image is determined. In this case, only the portion where no fiber exists transmits light and is bright, that is, the brightness is increased. The area of the portion where no fiber exists in the imaging region is thus determined. (4) The void ratio is calculated by subtracting the area of the portion where no fiber is present from the area of the shot region (measured area) and dividing the subtracted area by the area of the shot region (measured area). This calculation was performed using images at intervals of 20 μm in depth, and five void fractions were calculated. (5) The void ratios of the front surface (1 st fiber layer 2 a) and the back surface (2 nd fiber layer 2 b) of the front sheet 2 were each determined by calculating an average value of five void ratios. By comparing the void ratio, the distance between fibers can be determined. That is, when the porosity is large, the distance between fibers can be regarded as large. For example, the void ratio is 25.4% on the skin surface side (the 1 st fiber layer 2a: e.g., the surface of Cotton 100%) which is the front surface of the top sheet 2, and 24.5% on the non-skin surface side (the 2 nd fiber layer 2b: e.g., the surface of Cotton60% + 40% of synthetic fibers) which is the back surface.

Further, in compliance with JIS L1015: "A7.1.1" measurement of a7.1 fiber length "of appendix a of 2010 method of measuring the length of individual fibers on a glass plate with a scale of method a (standard method)" method of measuring the fiber length and average fiber length of fibers of a sheet such as a fiber layer. The above method is a test method corresponding to ISO 6989 released in 1981.

The mass per unit area of a sheet such as a fiber layer was measured according to the following measurement method. The fiber layer was cut into 5cm × 5cm pieces, and the mass was measured after drying treatment in an atmosphere of 100 ℃ or higher. Next, the mass per unit area of the sample was calculated by dividing the measured mass by the area of the sample. The average of the mass per unit area of the 10 samples was defined as the mass per unit area of the sheet.

Further, the thickness of a sheet such as a fiber layer was measured in accordance with the following measurement method. An enlarged image was taken from a direction perpendicular to the cut surface of the surface sheet 2 using a digital microscope VHX-100 manufactured by kynshi co. The magnified image is an image magnified to a magnification at which the entire surface sheet 2 in the thickness direction T can be captured, and the magnification is, for example, 20 to 50 times. The thickness of each fiber layer is measured in a 2D image converted from the resulting 3D image. The average of the thicknesses measured in the cut surfaces of the three different locations was taken as the thickness of the surface sheet 2.

As described above, in the sanitary napkin 1, the ratio of the water-retentive fibers in the 1 st fibrous layer 2a on the skin side of the topsheet 2 is relatively high, and therefore the skin feel of the topsheet 2 can be improved. Further, since the average fiber length of the water-retentive fibers contained in the 1 st fiber layer 2a is relatively long, it is possible to suppress the occurrence of fluffing due to insufficient interlacing between the fibers caused by excessively short average fiber length, and to suppress the decrease in the skin touch of the top sheet 2.

At this time, since the average fiber length of the water-retentive fibers contained in the 2 nd fiber layer 2b is shorter than the average fiber length of the water-retentive fibers contained in the 1 st fiber layer 2a, the fibers constituting the 2 nd fiber layer 2a can be brought closer to each other. Therefore, the average distance between the fibers of the 2 nd fiber layer 2b can be made shorter than the average distance between the fibers of the 1 st fiber layer 2a, so that the capillary phenomenon can be more strongly generated in the 2 nd fiber layer 2b, and the liquid excrement excreted to the skin-side surface of the 1 st fiber layer 2a can be quickly introduced into the 2 nd fiber layer 2b. In addition, the liquid excrement introduced into the 2 nd fiber layer 2b can be rapidly transferred to the absorbent body 4 through the 2 nd fiber layer 2b by the hydrophobic fibers.

In this case, in the 1 st fiber layer 2a, the liquid excrement can be drawn into the 2 nd fiber layer 2b while spreading over a wide range in the planar direction by the water-retentive fibers having a relatively long average fiber length. This allows the liquid excrement widely diffused in the planar direction in the topsheet 2 to be absorbed by the region of the absorbent body 4 large in the planar direction, and therefore, the absorption performance can be improved.

This improves the absorption performance of the sanitary napkin 1 while improving the tactile sensation of the topsheet 2.

In the case where the 2 nd fibrous layer 2b includes one or more fibrous layers on the non-skin side, that is, in the case where the top sheet 2 as a whole has a three-layer or multilayer structure, it is preferable that the proportion of the water-retentive fibers be relatively lower and the average fiber length of the water-retentive fibers be shorter as the fibrous layer closer to the non-skin side surface of the top sheet 2 is from the viewpoint of further improving the liquid permeability.

In the present embodiment, the fiber density of the 1 st fiber layer 2a is smaller than that of the 2 nd fiber layer 2b. That is, there is a gradient in fiber density such that the fiber density increases from the 1 st fiber layer 2a toward the 2 nd fiber layer 2b.

In the sanitary napkin 1 having such a structure, first, liquid excrement excreted to the skin side surface of the topsheet 2, that is, the surface of the 1 st fiber layer 2a when worn can be introduced into the 1 st fiber layer 2a. Then, the liquid excrement introduced into the 1 st fiber layer 2a can be stably transferred to the 2 nd fiber layer 2b by utilizing the gradient of the fiber density. This allows liquid excrement to be stably transferred from the 1 st fiber layer 2a containing relatively many water-retentive fibers to a layer (exemplified by the auxiliary sheet and the absorbent body 4) in contact with the non-skin side of the 2 nd fiber layer 2b through the 2 nd fiber layer 2b containing relatively few water-retentive fibers. Therefore, the top sheet 2 can have a good tactile sensation to the skin and improved absorption performance. The topsheet 2 of the sanitary napkin 1 may not have such a gradient in fiber density.

In the case where the non-skin side surface of the 2 nd fibrous layer 2b further includes one or more fibrous layers, that is, in the case where the surface sheet 2 has a three-layer or multi-layer structure, it is preferable that the fiber density is relatively higher as the fibrous layer is closer to the non-skin side surface of the surface sheet 2. This can further improve the liquid permeability from the skin-side fibrous layer to the non-skin-side fibrous layer, and can more stably transfer liquid excrement to the auxiliary sheet and the absorbent body 4.

In the case where the 2 nd fibrous layer 2b includes one or more fibrous layers on the non-skin side, that is, in the case where the surface sheet 2 as a whole has a three-layer or multi-layer structure, it is preferable that the fiber density is relatively higher as the fibrous layer is closer to the non-skin side surface of the surface sheet 2. This can further improve the liquid permeability from the skin-side fibrous layer to the non-skin-side fibrous layer, and can more stably transfer liquid excrement to the auxiliary sheet and the absorbent body 4.

The fiber density of a sheet such as a fiber layer is measured by the following measurement method, for example.

(1) The surface sheet 2 was cut into a size of 10mm × 10mm to obtain a sample. (2) The cut surface parallel to the thickness direction T of the sample was observed under magnification using a scanning electron microscope (JCM-5100, manufactured by Nippon electronics Co., ltd.). The magnification is a magnification (for example, 150 to 500 times) that can measure the cross section of 30 to 60 fibers in one screen. (3) The number of cross sections of the fibers in each fiber layer was measured by trisecting the observation area in the thickness direction T into a skin surface side layer, an intermediate layer, and a non-skin surface side layer, with the skin surface side layer being the 1 st fiber layer 2a and the non-skin surface side layer being the 2 nd fiber layer 2b. That is, the number of cross sections of the fibers cut in the cut section of a predetermined area is counted. (4) The number of cross sections of the obtained fibers was converted to 1mm per unit ² The number of cross sections of the fibers (2) is defined as the fiber density (root/mm) ² ). The measurement was performed at three places, and the average value of the measured values was taken as the fiber density of the sample. That is, as the fiber density, the density of the number of fibers is used. In other words, the number of fibers per unit area in a cross section parallel to the thickness direction T is used as the fiber density. In addition, as the fiber density, the root of the fiber per unit volume may be usedAnd (4) counting. The number of fibers per unit volume is determined by analysis using, for example, X-ray CT. The fiber density per unit area and the fiber density per unit volume are different in numerical value, but the relative comparison of the fiber densities between the fiber layers (example: comparison of the sizes) is the same.

In the present embodiment, the hydrophobic fibers contained in the 2 nd fiber layer 2b include heat-fusible fibers that are heat-fused to each other. That is, the heat-fusible fibers included in the hydrophobic fibers have bonding points (fusion points) where the heat-fusible fibers are bonded to each other by heat fusion at portions where the heat-fusible fibers are in contact with each other. Such mutually bonded heat-fusible fibers can be regarded as forming a matrix of thermoplastic resin fibers within the 2 nd fiber layer 2b.

In the sanitary napkin 1 having such a structure, the shape of the 2 nd fiber layer 2b can be stably maintained in the 2 nd fiber layer 2b by the heat-fusible fibers heat-fused to each other. Therefore, even if the average fiber length of the water-retentive fibers contained in the 2 nd fiber layer 2b is relatively short, the water-retentive fibers can be stably held between (in the matrix of) the heat-fusible fibers without being biased. This enables the liquid excrement introduced into the 2 nd fiber layer 2b to be stably transferred to the absorbent body 4 (and the auxiliary sheet 5) without being biased, thereby improving the absorption performance. The hydrophobic fibers of the sanitary napkin 1 may not include such heat-fusible fibers that are heat-fused to each other.

In the present embodiment, at least a part of the heat-fusible fibers of the 2 nd fiber layer 2b is exposed on the skin-side surface of the 1 st fiber layer 2a. That is, the heat-fusible fibers of the 2 nd fiber layer 2b continuously enter the 1 st fiber layer 2a from the 2 nd fiber layer 2b at least in part while stably maintaining the shape of the 2 nd fiber layer 2b, and these heat-fusible fibers reach the skin-side surface of the 1 st fiber layer 2a.

In the sanitary napkin 1 having such a structure, the heat-fusible fibers of the 2 nd fiber layer 2b continuously extend into the 1 st fiber layer 2a, whereby the water-retentive fibers of the 1 st fiber layer 2a can be stably held between the heat-fusible fibers. Thus, even if the average distance between the fibers of the 1 st fiber layer 2a is relatively long and the strength of the 1 st fiber layer 2a is relatively weak, collapse can be suppressed. Moreover, fuzz can also be suppressed by holding the water-retentive fibers of the 1 st fiber layer 2a between the heat-fusible fibers. This makes it possible to improve the texture of the first fiber layer 2a. Further, since a part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer 2b is present in the 1 st fiber layer 2a, transfer of liquid excrement from the 1 st fiber layer 2a to the 2 nd fiber layer 2b via the heat-fusible fibers can be promoted. This enables liquid excrement to be stably transferred to the absorbent body 4 (and the auxiliary sheet 5). The heat-fusible fibers of the 2 nd fiber layer 2b of the sanitary napkin 1 may not be exposed on the surface of the 1 st fiber layer 2a.

In the present embodiment, the fibers constituting the surface sheet 2 at both ends in the width direction W of the surface sheet 2 are oriented in the longitudinal direction L of the surface sheet 2, compared to the fibers constituting the surface sheet 2 at the center in the width direction W of the surface sheet 2. That is, in the top sheet 2, the orientation in the longitudinal direction L of the fibers is relatively small in the central portion in the width direction W, and the orientation in the longitudinal direction L of the fibers is relatively large in both end portions in the width direction W.

In the sanitary napkin 1 having such a configuration, since the fiber orientation of the topsheet 2 is relatively random in the central portion, the liquid excrement can be spread out in a substantially concentric manner, and since the fiber orientation is in the longitudinal direction L at both end portions, the liquid excrement reaching both end portions can be spread out in the longitudinal direction L. That is, the sanitary napkin 1 can be used as a whole, thereby improving the absorption performance. Further, since the number of fibers exposed from the edge is small at both ends of the top sheet 2 in the width direction W, friction against the skin is reduced, and a decrease in the tactile sensation of the skin can be suppressed. The fiber orientation of the topsheet 2 of the sanitary napkin 1 may be such that the fiber orientation in the longitudinal direction L is not relatively increased at both ends in the width direction W.

In the sanitary napkin 1, the excretory opening contact region XA is set slightly forward of the center in the longitudinal direction L and at the center in the width direction W in a plan view. The excretory opening contact region XA is a region that faces or contacts the excretory opening of the wearer when the sanitary napkin 1 is worn. The excretory opening contact region XA is set according to the type and use of the absorbent article. The excretory opening contact region XA is set to a length of about 1/4 to 1/2 of the total length of the absorbent body 4 in the longitudinal direction L, for example, at a position slightly forward of the center of the absorbent body 4 in the longitudinal direction L, and is set to a width of about 1/2 to 1/3 of the total length of the absorbent body 4 in the width direction W, at substantially the center of the absorbent body 4 in the width direction W.

In the present embodiment, the sanitary napkin 1 includes a pair of compressed portions (compressed grooves) 12, 12 continuously or intermittently located on both outer sides in the width direction W of the excretory opening contact region XA. In the present embodiment, the sanitary napkin 1 further includes a pair of compressing portions (compressing grooves) 13 and 13 at the rear of the pair of compressing

portions

12 and 12 in the longitudinal direction L, compressing portions (compressing grooves) 11 and 14 at the front and rear of the excretory opening contact region XA in the longitudinal direction L, and a plurality of dot-shaped compressing portions 15 in the excretory opening contact region XA. The compressed portions 11 to 15 are formed by compressing the topsheet 2 and the absorbent body 4 in the thickness direction T. That is, the topsheet 2, the auxiliary sheet 5, and the absorber 4 (the skin-side core wrap 4b and the absorbent core 4 a) are compressed in the thickness direction T. In this case, each of the compressed parts has a low-density part LPA formed at a shallow position by being weakly compressed and having a relatively low fiber density, and a high-density part HPA formed at a deep position by being strongly compressed and having a relatively high fiber density. The references of "shallow" and "deep" are the skin-side surface of the surface sheet 2. The low-density portion LPA and the high-density portion HPA can be referred to as a bottom at a shallow position and a bottom at a deep position of each compression portion. The low-density portion LPA and the high-density portion HPA of the compression portions 11 to 15 are positioned within the absorbent core 4 a. However, the high-density portions HP may reach the core wrap 4b on the non-skin side. The shapes of the compression portions 11 to 15 are arbitrary. The sanitary napkin 1 may not include at least one of the compressed portions 11 to 15.

In the present embodiment, at least a part of the heat-fusible fibers of the 2 nd fiber layer 2b is exposed on the surface inside the compressed part in at least one of the compressed parts 11 to 15.

In the sanitary napkin 1 having such a configuration, the heat-fusible fibers are present in the 1 st fiber layer 2a so as to be exposed on the inner surface of the compressed portion, and the water-retentive fibers of the 1 st fiber layer 2a can be stably held between the heat-fusible fibers even in the compressed portion. Thus, even in the compressed portion, even if the strength of the 1 st fiber layer 2a is relatively weak, collapse and fuzz can be suppressed, and the texture of the 1 st fiber layer 2a in the compressed portion can be made better. Further, since part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer 2b is present in the 1 st fiber layer 2a in the compression part, the transfer of the liquid excrement from the 1 st fiber layer 2a in the compression part to the 2 nd fiber layer 2b through the heat-fusible fibers can be promoted. This makes it possible to more stably transfer the liquid excrement to the absorbent body 4 (and the auxiliary sheet 5). In the sanitary napkin 1, the heat-fusible fibers may not be exposed on the surface inside the compressed portion.

In the present embodiment, at least a part of the heat-fusible fibers of the 2 nd fiber layer 2b is exposed on the surface of the low-density portion LPA of at least one of the compressed portions 11 to 15.

In the sanitary napkin 1 having such a structure, the heat-fusible fibers are present in the 1 st fiber layer 2a so as to be exposed on the surface of the low-density portion LPA, whereby the water-retentive fibers of the 1 st fiber layer 2a in the low-density portion LPA can be stably held between the heat-fusible fibers. As a result, even if the strength of the 1 st fiber layer 2a in the low-density portion LPA is relatively weak, collapse and fuzz can be suppressed, and the skin feel of the 1 st fiber layer 2a in the low-density portion LPA can be made better. Further, since a part of the heat-fusible fibers having no water retentivity in the 2 nd fiber layer 2b is present in the 1 st fiber layer 2a in the low density portion LPA, the transfer of the liquid excrement from the 1 st fiber layer 2a in the low density portion LPA to the 2 nd fiber layer 2b via the heat-fusible fibers can be promoted. This makes it possible to more stably transfer the liquid excrement to the absorbent body 4 (and the auxiliary sheet 5) in the end. In the sanitary napkin 1, the heat-fusible fibers may not be exposed on the surface of the low-density portion LPA.

In the present embodiment, the surface sheet 2 has a concavo-convex structure. Fig. 3 shows a configuration example of the top sheet 2 of the embodiment, fig. 3 (a) is a plan view of the top sheet 2, and fig. 3 (b) is a cross-sectional view taken along line IIb-IIb of fig. 3 (a). The 1 st fiber layer 2a has a 1 st upper surface 2aE on the upper side and a 1 st lower surface 2aF on the lower side in the thickness direction T, and the 2 nd fiber layer 2b has a 2 nd upper surface 2bE on the upper side and a 2 nd lower surface 2bF on the lower side in the thickness direction T. The 1 st lower surface 2aF and the 2 nd upper surface 2bE are virtual boundaries between the two fiber layers, but are not strict boundaries because some of the fibers of the two fiber layers enter into the other fiber layer by being entangled. The 1 st fiber layer 2a has a plurality of protrusions 21 extending continuously in the 1 st upper surface 2aE in the longitudinal direction L and located at positions spaced apart in the width direction W, and a plurality of recesses 22 extending continuously in the longitudinal direction L and located between the protrusions 21 adjacent to each other. In the present embodiment, each of the plurality of projections 21 is formed to be solid. Since the plurality of projections 21 are formed to be solid in this way, the projections 21 are less likely to be deformed, and the liquid transfer from the projections 21 which are likely to come into contact with the body of the wearer to the absorbent body 4 is excellent, so that the dryness of the surface of each projection 21 can be improved.

The 2 nd fiber layer 2b has a substantially flat shape except for a recessed portion 23 (described later) formed by compression. However, the 2 nd upper surface 2bE may slightly rise in the upward direction of the thickness direction T at a position corresponding to the convex portion 21. Similarly to the first fiber layer 2a (but in the opposite direction to the thickness direction T), the 2 nd lower surface 2bF may have a plurality of projections extending continuously in the longitudinal direction L and located at positions spaced apart in the width direction W, and a plurality of recesses extending continuously in the longitudinal direction L and located between projections adjacent to each other, in the 2 nd fiber layer 2b. In this case, it is preferable that the positions of the convex portions 21 and the concave portions 22 of the 1 st fiber layer 2a are the same as the positions of the convex portions and the concave portions of the 2 nd fiber layer 2b in a plan view.

The 1 st fiber layer 2a and the 2 nd fiber layer 2b are joined to each other by being interwoven. Examples of the interlacing method include a Spunlace (Spunlace) method and a Water jet (Water jet) method. However, the interlacing method is not limited to this example, and other interlacing methods such as a hot air method may be used.

In the present embodiment, S1 < S3 < S2 where S1 denotes the fiber density of the top portion 21T of the convex portion 21, S2 denotes the fiber density of the bottom portion 22B of the concave portion 22, and S3 denotes the fiber density of the region MP between the top portion 21T of the convex portion 21 and the bottom portion 22B of the concave portion 22.

In the sanitary napkin 1 having such a structure, in the topsheet, the capillary phenomenon acts from the top 21T of the convex portions 21 having a low fiber density S1 toward the bottom 22B of the concave portions 22 having a high fiber density S3 via the region MP having a medium fiber density S2. Therefore, the liquid excrement excreted on the surface of the topsheet 2 closest to the skin (the top 21T of the projection 21 or the vicinity thereof) can be more easily drawn into the bottom 22B of the depressed portion 22 located in the vicinity of the surface of the topsheet 2 on the non-skin side. This enables the liquid excrement to be transferred more stably from the skin-side surface of the topsheet 2 to the absorbent body 4 (and the auxiliary sheet 5) through the non-skin-side surface of the topsheet 2. Further, the liquid excrement temporarily absorbed can be made less likely to be rewet by the gradient of the fiber density (S1 < S3 < S2). Further, since the fiber density of the convex portions 21 is low, the wearer can feel softness. Therefore, the surface sheet can have a good tactile sensation to the skin and improved absorption performance. The sanitary napkin 1 may not have the above-described uneven structure in the topsheet 2, or may not have the above-described fiber density gradient.

In the present embodiment, the top sheet 2 has a plurality of depressions 23 formed by compressing the 1 st fiber layer 2a and the 2 nd fiber layer 2b in the thickness direction T in each of the plurality of depressions 22. The plurality of recessed portions 23 are disposed at regular or non-regular intervals intermittently along the longitudinal direction L in each recessed portion 22. The recessed portions 23 may or may not be at the same position in the longitudinal direction L in the recessed portions 22 adjacent to each other in the width direction W. In the present embodiment, the concave portions 22 are arranged in a lattice pattern. The shape of the recessed portion 23 in plan view is arbitrary, such as an elliptical shape.

In the sanitary napkin 1 having such a configuration, the 1 st fiber layer 2a and the 2 nd fiber layer 2b are fixed by compression in the thickness direction T in the plurality of depressions 23, and therefore, the water-retentive fibers of the 1 st fiber layer are compressed. This can suppress fluffing of the water-retentive fibers and can maintain the skin feel of the top sheet satisfactorily. The sanitary napkin 1 may not have the depressions 23 in the topsheet 2.

In the present embodiment, the auxiliary sheet 5 is a liquid-permeable sheet. Examples of the auxiliary sheet 5 include a liquid-permeable nonwoven fabric, a woven fabric, and a composite sheet of these nonwoven fabric and woven fabric. The auxiliary sheet 5 has a shape slightly larger than the surface sheet 2 in the width direction W. The auxiliary piece 5 has a pair of

ring portions

5L, 5L at both ends in the width direction W. The pair of

ring portions

5L and 5L are formed by folding back the both side portions of the auxiliary sheet 5 in the width direction W in a ring shape toward the inner side and the non-skin side (lower side in the thickness direction T) of the auxiliary sheet 5 in the width direction W. The end portions of both side portions of the folded-back auxiliary sheet 5 are joined to a pair of inner end portions of the pair of

side sheets

6, 6 facing each other by a pair of adhesive portions (not shown) intermittently or continuously extending in the longitudinal direction L. In addition, the ring portion 5L does not include an elastic member. The end portions of the folded-back auxiliary sheet 5 on both sides are joined to the non-skin-side surface of the auxiliary sheet 5 by a pair of adhesive portions intermittently or continuously extending in the longitudinal direction L.

In the surface sheet 2 containing a large amount of water-retentive fibers of the present embodiment, when the edges thereof are rubbed, the water-retentive fibers are easily separated from the edges thereof and fall off. Here, in the present embodiment, the dimension of the auxiliary sheet 5 in the width direction W is larger than the dimension of the front sheet 2 in the width direction W. That is, in a plan view, the auxiliary sheet 5 is formed to have a pair of protruding portions protruding outward in the width direction W from both end edges in the width direction W of the front sheet 2. In the present embodiment, a pair of

loop portions

5L, 5L are formed as the pair of projecting portions at both ends of the auxiliary piece 5 in the width direction W. This allows the pair of

loop portions

5L, 5L (the pair of projecting portions) to receive the force applied from the thighs of the wearer by the sanitary napkin 1, and the edges of the topsheet 2 in the width direction W and the thighs can be made less likely to rub against each other. This can suppress friction between the both end edges in the width direction W of the top sheet 2, and the water-retentive fibers can be prevented from coming loose and falling off from the both end edges in the width direction W of the top sheet 2, thereby suppressing a decrease in the tactile sensation of the skin. In particular, when the pair of

loop portions

5L, 5L are used as the pair of protruding portions, the force applied from the thighs of the wearer to the sanitary napkin 1 can be softly received by the cushioning effect of the pair of loop portions 5L, and the feel of the skin felt by the wearer can be further improved. In particular, when the water-retentive fibers are cotton, the above-described effects are remarkable.

In the present embodiment, the auxiliary sheet 5 has a fiber density higher than that of the 2 nd fiber layer 2b. In the sanitary napkin 1 having such a structure, the liquid excrement drawn into the 2 nd fiber layer 2b can be transferred to the auxiliary sheet 5 more stably by utilizing the capillary phenomenon. This makes it possible to transfer the liquid excrement from the topsheet 2 to the absorbent body 4 more stably through the auxiliary sheet 5, and to improve the skin feel of the topsheet 2 and the absorption performance. In addition, when the fiber density of the 1 st fiber layer 2a < the fiber density of the 2 nd fiber layer 2b < the fiber density of the auxiliary sheet 5, the liquid excrement can be transferred to the auxiliary sheet 5 more stably by utilizing the capillary phenomenon, which is preferable. The sanitary napkin 1 may not include the auxiliary sheet 5 or the ring portion 5L.

In the present embodiment, when the auxiliary sheet 5 contains water-retentive fibers corresponding to the surface sheet 2 and the surface sheet 2 contains cellulosic fibers (preferably cotton), it is preferable that the auxiliary sheet 5 contains cellulosic fibers (preferably cotton). In the sanitary napkin 1 having such a structure, the water-retentive fibers, preferably cellulosic fibers, and more preferably cotton, having high liquid diffusibility are communicated from the 1 st fibrous layer of the top sheet 2 to the auxiliary sheet 5 through the 2 nd fibrous layer. Therefore, by utilizing the liquid diffusion of the liquid excrement by the fibers, the liquid excrement can be transferred more stably from the topsheet 2 to the absorbent body 4 via the auxiliary sheet 5, and the skin feel of the topsheet 2 can be improved and the absorption performance can be improved. In the sanitary napkin 1, the auxiliary sheet 5 may not contain water-retentive fibers, cellulose fibers, or cotton. In this case, as the auxiliary sheet 5, for example, a nonwoven fabric of hydrophobic fibers can be cited, and among them, a nonwoven fabric of thermoplastic resin fibers is suitably used.

The absorbent body 4 is a layer having liquid absorbing performance and liquid retaining performance, and in the present embodiment, has a shape that is long in the longitudinal direction L and both ends in the longitudinal direction L are substantially semicircular in a plan view. In the present embodiment, the absorbent body 4 includes an absorbent core 4a and a core wrap 4b covering the absorbent core 4 a. Examples of the absorbent core 4a include a liquid-retaining material containing water-absorbent fibers such as pulp fibers, and a water-absorbent material such as a Super Absorbent Polymer (SAP). The core wrap layer 4b may be a liquid-permeable sheet including a hydrophilic nonwoven fabric, such as tissue paper.

In the present embodiment, when the top sheet 2 contains a cellulose fiber (preferably cotton), the absorbent member 4 preferably contains a cellulose fiber (preferably cotton) corresponding to the top sheet 2. In this case, it is preferable that a part of the cellulose fibers contained in the top sheet 2 contact the cellulose fibers contained in the absorbent member 4.

In the sanitary napkin 1 having such a structure, the cellulose-based fibers having high liquid diffusibility are communicated from the 1 st fiber layer 2a of the topsheet 2 to the absorbent member 4 via the 2 nd fiber layer 2b (via the auxiliary sheet 5 as the case may be). Therefore, by utilizing the liquid diffusion of the liquid excrement by the cellulose fiber, the liquid excrement can be directly diffused from the topsheet 2 to the absorbent member 4. Thereby enabling the absorption performance to be improved. In the sanitary napkin 1, the absorbent member 4 may not contain cellulose fibers or cotton.

In the present embodiment, the side sheet 6 is a waterproof sheet. Examples of the side sheet 6 include a nonwoven fabric subjected to a water repellent treatment and a synthetic resin film having air permeability. In the present embodiment, the back sheet 3 is a liquid impermeable sheet. Examples of the back sheet 3 include a liquid-impermeable nonwoven fabric, a synthetic resin film, and a composite sheet of these nonwoven fabric and synthetic resin film. In the present embodiment, the wing portions 9 are formed by the side sheets 6 and the back sheet 3.

In the sanitary napkin 1 of the present embodiment, the topsheet 2 is bonded to the auxiliary sheet 5 with an adhesive (hot melt adhesive, for example), and the auxiliary sheet 5 and the portions of the pair of

side sheets

6 and 6 facing the absorbent body 4 are bonded to the absorbent body 4 with an adhesive. The pair of

side sheets

6, 6 and the portion of the absorbent body 4 facing the back sheet 3 are joined to the back sheet 3 with an adhesive or the like.

In the present embodiment, the sanitary napkin 1 further includes a plurality of bonded portions 7 and a pair of bonded

portions

8 and 8. The plurality of adhesive sections 7 have, for example, a substantially rectangular shape, are arranged on the non-skin side surface of the back sheet 4 so as to overlap the absorbent body 4 in plan view, extend continuously along the longitudinal direction L, and are arranged intermittently in the width direction W. The pair of

adhesive portions

8, 8 have, for example, a substantially rectangular shape, are arranged on the surface of the back sheet 4 on the non-skin side so as to overlap the pair of wing portions 9, 9 in plan view, and extend continuously along the longitudinal direction L. Examples of the

adhesive portions

7 and 8 include hot melt adhesives.

Next, an example of a method for manufacturing the sanitary napkin 1 according to the present embodiment will be described.

Fig. 4 is a schematic diagram showing a configuration example of a manufacturing apparatus 300 for a sanitary napkin 1. Fig. 5 is a diagram schematically illustrating a method of manufacturing the sanitary napkin 1. The manufacturing apparatus 300 is related to conveyance of a material such as a sheet or a semi-finished product, and has a conveyance direction MD, a transverse direction CD, and a vertical direction TD. In the present embodiment, the material and the semi-finished product have the same longitudinal direction, the same width direction, and the same thickness direction as the conveyance direction MD, the transverse direction CD, and the vertical direction TD.

First, a 2 nd web P11 corresponding to the 2 nd fiber layer 2b is formed by the 1 st carding machine 110. Carding machine 1 is a dry roller card (roller card) that uses a single cylinder card (single card) or a double cylinder card (double card) commonly used to form webs. The 2 nd web P11 contains water-retentive fibers and hydrophobic fibers. The 2 nd web P11 is conveyed in the conveyance direction MD by a conveying device (not shown).

Next, a 1 st web P12 corresponding to the 1 st fiber layer 2a is formed by the 2 nd carding machine 120. No. 2 card 120 is also a dry roller card similar to No. 1 card 110. The 1 st web P12 contains water-retentive fibers. The 1 st web P12 is stacked on the 2 nd web P11 being conveyed by the conveying device. Thereby, the 1 st web P12 and the 2 nd web P11 are stacked to form the composite web P13 having a double-layer structure, and are conveyed in the conveyance direction MD by the conveyance device. In addition, the ratio of each fiber in each web can be controlled by the ratio of the raw material fiber supplied to each carding machine.

Next, the composite fiber web P13 having the double-layer structure is subjected to water jet treatment by the water jet treatment machine 130 to interlace fibers with each other. Thereby forming a 1 st continuous sheet (spunlace nonwoven) P14. Here, the water jet treatment is carried out by placing the composite fiber web P13 on a continuously moving mesh belt, and jetting water at high pressure from the upper surface side of the composite fiber web P13 to interlace fibers with each other. The properties of the 1 st continuous sheet P14 obtained by the water jet treatment can be appropriately adjusted or changed depending on the mass of each web, the hole diameter of the jet nozzle, the number of holes (pitch) of the jet nozzle, the web passing speed, and the like. Thereafter, the 1 st continuous sheet P14 having passed through the water jet processing machine 130 is dried by the dryer 140. The dried 1 st continuous sheet P15 is conveyed in the conveyance direction MD by the conveyance device.

The method of forming the fiber web corresponding to each fiber layer is not limited to the above-described method, and for example, a wet method or the like may be used. The method of bonding the web is not limited to the above-described method, and for example, water-jet interlacing, needle punching, or the like may be employed. Further, the 1 st continuous sheet P15 may be produced at a manufacturing plant different from the manufacturing plant of the sanitary napkin 1, wound into a roll, and then supplied in the rolled state to the manufacturing plant of the sanitary napkin 1.

Next, the 1 st continuous sheet P16, which is the 1 st continuous sheet P15 conveyed by the conveying device (not shown) or unwound from the roll (not shown), is conveyed in the conveyance direction MD and supplied to the shaping device 210. The shaping device 210 includes shaping

rollers

210a and 210b, and the shaping

rollers

210a and 210b have concave and convex portions extending in the circumferential direction on the outer circumferential surface thereof and engaging with each other. Then, the 1 st continuous sheet P16 is nipped between the uneven portions of the shaping

rollers

210a and 210b, and an uneven structure extending in the conveyance direction MD is provided. After that, the 1 st continuous sheet P16 is conveyed in the conveyance direction MD. Thereby forming a continuous surface sheet P16 for the surface sheet 2.

Next, the continuous auxiliary sheet AS for the auxiliary sheet 5 unwound from the material roll WR3 is conveyed in the conveyance direction MD and supplied to the heating device 220. Next, the continuous auxiliary sheet AS is heat-treated to restore the volume, and then supplied to the coating device 302. Next, an adhesive (exemplified by a hot-melt adhesive) is applied in a predetermined pattern (exemplified by a spiral pattern) to one surface of the continuous auxiliary sheet AS. Thereafter, the continuous auxiliary sheet AS and the continuous-surface sheet P16 are conveyed in the conveyance direction MD and fed to the joining device 230, and are nipped between the pair of joining

rollers

230a and 230b of the joining device 230 to be joined. Thereby, as shown in fig. 5 (a), a continuous surface sheet P17 is formed.

Subsequently, the continuous surface sheet P17 is conveyed in the conveyance direction MD and supplied to the coating device 303. Then, the continuous-surface sheet P17 is coated with an adhesive (exemplified by a hot-melt adhesive) in a predetermined pattern along the conveyance direction MD on a surface below (the continuous auxiliary sheet AS of) the continuous-surface sheet P17 in the vertical direction TD and at an end in the transverse direction CD. Subsequently, the continuous surface sheet P17 is conveyed in the conveyance direction MD and supplied to the loop forming device 240. Then, both end portions in the transverse direction CD of the continuous auxiliary sheet AS of the continuous surface sheet P17 are folded back into a loop toward the central portion by a folding jig such AS a flap of the loop forming device 240. As a result, a pair of side portions ASL, ASL corresponding to the pair of

ring portions

5L, 5L are formed on both sides of the continuous surface sheet P17 in the transverse direction CD. Thereby, as shown in fig. 5 (b), a continuous surface sheet P18 is formed.

Next, the continuous side sheet SS for the side sheet 6 unwound from the material roll WR4 is conveyed in the conveyance direction MD and supplied to the cutting device 250. Then, the continuous side sheet SS is cut in the transverse direction CD in two halves along the conveyance direction MD at the center position in the transverse direction CD to form a pair of continuous side sheets SSa, SSb adjacent to each other in the transverse direction CD. Thereafter, the pair of continuous side pieces SSa, SSb are supplied to the pair of coating devices 303a, 303b. Then, an adhesive (exemplified by a hot-melt adhesive) is applied in a predetermined pattern (exemplified by a stripe pattern) to the inner ends in the transverse direction CD of each of the pair of continuous side sheets SSa, SSb. Next, the pair of continuous side sheets SSa, SSb and the continuous surface sheet P8 are conveyed in the conveyance direction MD and supplied to the joining device 260, and are nipped between the pair of joining

rollers

260a, 260b of the joining device 260 and joined. Thereby, the pair of side portions ASL, ASL of the continuous surface sheet P18 are joined to the pair of continuous side sheets SSa, SSb, respectively. Thereby, as shown in fig. 5 (c), the continuous surface sheet P2 is formed.

Next, the continuous surface sheet P2 is supplied to the application device 305, and an adhesive (hot melt adhesive, for example) is applied in a predetermined pattern to the surface of the continuous side sheet P on the side close to the pair of continuous side sheets SSa, SSb. Next, the continuous surface sheet P2 and the absorbent bodies P3 aligned in the conveyance direction MD at predetermined intervals are conveyed in the conveyance direction MD and supplied to the joining device 270. Then, the continuous surface sheet P2 and the absorbent body P3 are nipped between a pair of joining

rollers

270a, 270b of the joining device 270 and joined. Thereby forming a semi-finished product P4. Next, the semi-finished product P4 is conveyed in the conveyance direction MD and supplied to the compression device 280. In the compression device 280, an emboss roller 280a having a convex portion for compression on the outer peripheral surface and an anvil roller 280b are disposed to face each other. Then, the half product P4 is nipped between the emboss roller 280a and the anvil roller 280b to be compressed. As a result, compressed portions 11 to 15 extending from the continuous topsheet P2 to the absorbent body P3 in the vertical direction TD are formed, thereby forming the semi-finished product P5. Further, the respective compression portions may be compressed by different compression devices. Subsequently, the continuous back sheet BS for the back sheet 3 is conveyed in the conveyance direction MD from the 4 th material roller WR4 and supplied to the joining device 290. An adhesive (hot melt adhesive, for example) is applied to one surface of the continuous back sheet BS by the application device 306. On the other hand, the semi-finished product P5 is conveyed in the conveyance direction MD and supplied to the joining device 290. Then, the continuous back sheet BS and the semi-finished product P5 are nipped between a pair of joining

rollers

290a, 290b of the joining device 290 for joining. Thereby, as shown in fig. 5 (d), a semi-finished product P6 is formed in which the continuous back sheet BS and the semi-finished product P5 are stacked in the vertical direction TD. Thereafter, the release sheet CT (adhesive portions 7 and 8) with an adhesive is joined to the semi-finished product P6, and the periphery of the semi-finished product P6 to which the release sheet CT is joined is cut into the shape of the sanitary napkin 1, thereby forming the sanitary napkin 1.

The sanitary napkin 1 is manufactured as described above.

However, as a method of interlacing the composite fiber web P13 having the double-layer structure, a hot air method may be used. That is, the method is a method in which the composite web P13 is conveyed to a heating device, and the fibers of the composite web P13 are entangled with each other by heated air in the heating device.

(embodiment 2)

Hereinafter, differences from the sanitary napkin 1 according to embodiment 1 will be mainly described with respect to the sanitary napkin 1 according to embodiment 2. The sanitary napkin 1 of the present embodiment is different from the sanitary napkin 1 of embodiment 1 in that the fiber density of the 1 st fiber layer 2a is smaller than the fiber density of the 2 nd fiber layer 2b. That is, in the sanitary napkin 1 of the present embodiment, there is a gradient in fiber density such that the fiber density increases from the 1 st fiber layer 2a toward the 2 nd fiber layer 2b. Here, the fiber density is a density of the number of fibers.

In the sanitary napkin 1 having such a structure, the fibers constituting the 2 nd fiber layer 2b can be brought closer to each other because the fiber density of the 2 nd fiber layer 2b is higher than the fiber density of the 1 st fiber layer 2a. Therefore, the average distance between the fibers of the 2 nd fiber layer 2b can be made shorter than the average distance between the fibers of the 1 st fiber layer 2a, so that the capillary phenomenon can be more strongly generated in the 2 nd fiber layer 2b, and the liquid excrement excreted to the skin-side surface of the topsheet 2, that is, the surface of the 1 st fiber layer 2a when worn can be taken into the 1 st fiber layer 2a. Then, the liquid excrement introduced into the 2 nd fiber layer 2b can be quickly transferred to the absorbent body 4 through the 2 nd fiber layer 2b by the hydrophobic fibers. This enables stable transfer of liquid excrement from the 1 st fiber layer 2a containing relatively large amounts of water-retentive fibers to a layer (exemplified by an auxiliary sheet and an absorbent body 4) in contact with the non-skin side of the 2 nd fiber layer 2b through the 2 nd fiber layer 2b containing relatively small amounts of water-retentive fibers.

In this case, in the 1 st fiber layer 2a, the liquid excrement can be taken into the 2 nd fiber layer 2b while being spread over a wide range in the planar direction by the water-retentive fibers. This allows the liquid excrement spreading widely in the planar direction in the topsheet 2 to be absorbed by the region of the absorbent body 4 large in the planar direction, and therefore, the absorption performance can be improved.

Therefore, the top sheet 2 can have a good tactile sensation to the skin and improved absorption performance.

In the present embodiment, the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b may be shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a, as in the case of the 1 st embodiment, but conversely, the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b may not be shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a. When the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b is shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a, the same effect as that obtained when the fiber density of the 1 st fiber layer 2a is lower than that of the 2 nd fiber layer 2b in embodiment 1 can be obtained.

On the other hand, when the average fiber length of the water-retentive fibers of the 2 nd fiber layer 2b is not shorter than the average fiber length of the water-retentive fibers of the 1 st fiber layer 2a, the fiber length of the water-retentive fibers of the 2 nd fiber layer 2b is not particularly limited, and may be, for example, the same value as that of the 1 st fiber layer 2a, and may be, for example, 10mm to 80mm.

The absorbent article of the present invention is not limited to the above-described embodiments, and can be appropriately combined, modified, and the like without departing from the object and the gist of the present invention.

Description of the reference numerals

1. Sanitary napkins (absorbent articles); 2. a surface sheet; 2a, a 1 st fiber layer; 2b, 2 nd fiber layer.

Claims

1. An absorbent article comprising a surface sheet, a back sheet, and an absorbent body located between the surface sheet and the back sheet, wherein,

the surface sheet includes:

a 1 st fiber layer containing water-retentive fibers; and

a 2 nd fibrous layer adjacent to the non-skin side of the 1 st fibrous layer and comprising hydrophobic fibers and water-retentive fibers,

the water-retentive fibers are fibers having the property of absorbing and retaining water,

the skin-side surface of the 1 st fiber layer constitutes the skin-side surface of the surface sheet,

the non-skin side surface of the 2 nd fibrous layer constitutes the non-skin side surface of the topsheet,

constitute the fibrous proportion of water retention in the fibre of 1 st fibrous layer is greater than constitute the fibrous proportion of water retention in the fibre of 2 nd fibrous layer,

the average fiber length of the water-retentive fibers of the 2 nd fibrous layer is shorter than the average fiber length of the water-retentive fibers of the 1 st fibrous layer,

the fibrous average fiber length of hydrophobicity is compared respectively of 2 nd fibrous layer 1 st fibrous layer and 2 nd fibrous layer the fibrous average fiber length of water retention is long.

2. The absorbent article of claim 1, wherein,

the hydrophobic fibers contained in the 2 nd fiber layer include heat-fusible fibers thermally fused to each other.

3. The absorbent article of claim 2, wherein,

at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed at the skin-side surface of the 1 st fiber layer.

4. The absorbent article according to claim 2 or 3, wherein,

the absorptive article has a compressed part formed by compressing the top sheet and the absorptive body in the thickness direction of the absorptive article,

at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed on the surface inside the compressed part.

5. The absorbent article according to claim 4,

the compression section includes:

a low-density portion having a shallow depth in the thickness direction of the absorbent article; and

a high-density portion having a deep depth in the thickness direction of the absorbent article,

at least a part of the heat-fusible fibers of the 2 nd fiber layer is exposed at a surface of the low-density portion.

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

the surface sheet has:

a plurality of protrusions extending in the longitudinal direction of the absorbent article and located at positions spaced apart in the width direction of the absorbent article; and

a plurality of concave portions extending in a longitudinal direction of the absorbent article and located between mutually adjacent convex portions,

in the surface sheet, S1 < S3 < S2 where S1 is the fiber density at the top of the convex portion, S2 is the fiber density at the bottom of the concave portion, and S3 is the fiber density in the region between the top of the convex portion and the bottom of the concave portion.

7. The absorbent article of claim 6,

the top sheet has a plurality of concave portions compressed from the 1 st fiber layer toward the 2 nd fiber layer in the thickness direction of the absorbent article in each of the plurality of concave portions.

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

the water-retentive fibers contained in the surface sheet are cellulose-based fibers,

the absorbent body contains a cellulose fiber,

a part of the cellulose-based fibers contained in the top sheet is in contact with the cellulose-based fibers contained in the absorbent.

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

the fibers constituting the surface sheet at both ends in the width direction of the surface sheet are oriented in the longitudinal direction of the surface sheet, compared to the fibers constituting the surface sheet at the center in the width direction of the surface sheet.

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

the water-retentive fiber contained in the surface sheet is cotton.

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

the absorbent article further comprises an auxiliary sheet positioned between the topsheet and the absorbent body,

the dimension of the surface sheet in the width direction is smaller than the dimension of the auxiliary sheet in the width direction.

12. An absorbent article comprising a front sheet, a back sheet, and an absorbent body located between the front sheet and the back sheet, wherein,

the surface sheet includes:

a 1 st fiber layer containing water-retentive fibers; and

the fiber density of the 1 st fiber layer is less than the fiber density of the 2 nd fiber layer,

13. The absorbent article of claim 12,

an auxiliary sheet having a higher fiber density than that of the 2 nd fiber layer is further included between the surface sheet and the absorbent body.

14. The absorbent article according to claim 12 or 13, wherein,

15. The absorbent article of claim 14,

16. The absorbent article of claim 14,

17. The absorbent article of claim 16, wherein,

the compression section includes:

18. The absorbent article according to claim 12 or 13, wherein,

the surface sheet has:

in the surface sheet, S1 < S3 < S2, where S1 is a fiber density at the top of the convex portion, S2 is a fiber density at the bottom of the concave portion, and S3 is a fiber density in a region between the top of the convex portion and the bottom of the concave portion.

19. The absorbent article of claim 18,

20. The absorbent article according to claim 12 or 13, wherein,

the absorbent body contains a cellulose fiber,

21. The absorbent article according to claim 12 or 13, wherein,

22. The absorbent article according to claim 12 or 13, wherein,

the water-retentive fiber contained in the surface sheet is cotton.

23. The absorbent article according to claim 12 or 13, wherein,