Absorbent article

Abstract

The utility model provides an absorbent article which is not easy to generate wrinkle on the skin side. An absorbent article (1) is characterized by having a length direction, a width direction and a thickness direction in an unfolded state, and having: a skin side layer (2) which is provided at a position closest to the skin side in a central portion in the width direction; a non-skin side layer (3) which is provided at a position closer to the non-skin side than the skin side layer (2); and a liquid-impermeable outer layer (4) which is provided at a position closer to the non-skin side than the non-skin side layer (3), the skin side layer (2) and the non-skin side layer (3) each having a plurality of fibers including latent crimped fibers, and the plurality of fibers in the skin side layer (2) and the non-skin side layer (3) are not fused to each other.

Description

Technical Field

[0001] This utility model relates to an absorbent article. Background Technology

[0002] Previously, absorbent articles such as sanitary napkins, disposable diapers, and absorbent pads were known. For example, Patent Document 1 discloses a sanitary napkin having a surface sheet disposed on the skin-contact side, a back sheet disposed on the non-skin-contact side, and an absorbent body disposed between the surface sheet and the back sheet. The absorbent body in Patent Document 1 is formed of pulp fibers or the like.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-176412 Utility Model Content

[0006] Problems to be solved by utility models

[0007] In patent document 1, absorbent articles such as sanitary napkins may develop wrinkles and creases on the skin-friendly side due to the wearer's body shape and movement while wearing them. There are concerns that these wrinkles and creases may detract from the aesthetics of the absorbent article, cause discomfort to the wearer's skin due to the rigidity of the wrinkles, or cause waste to flow along the wrinkles and leak outside the absorbent article.

[0008] This invention was made in view of the above-mentioned problems, and its purpose is to provide an absorbent article that is less prone to wrinkling on the side of the skin.

[0009] Solution for solving the problem

[0010] The main utility model for achieving the above-mentioned objective is an absorbent article, characterized in that, in its unfolded state, the absorbent article has a length direction, a width direction, and a thickness direction, and comprises: a skin-side layer, the central portion of which is located closest to the skin in the width direction; a non-skin-side layer, located closer to the non-skin side than the skin-side layer; and a liquid-impermeable outer layer, located closer to the non-skin side layer than the non-skin-side layer, wherein the skin-side layer and the non-skin-side layer each have a plurality of fibers comprising potentially curled fibers, and the plurality of fibers in the skin-side layer and the non-skin-side layer are not fused together.

[0011] Preferably, the non-skin side layer has a linear high-density portion where the fiber density is higher than the surrounding area.

[0012] Preferably, the absorbent article has a recessed portion along the thickness direction on the skin side of the non-skin side layer.

[0013] Preferably, no adhesive is provided between the skin side layer and the non-skin side layer at the central portion in the width direction.

[0014] Preferably, the thickness of the skin side layer is greater than the thickness of the non-skin side layer.

[0015] Preferably, the skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, the average narrowness of the non-skin side region in the narrowness evaluation test used to quantitatively evaluate the narrowness of the gaps is smaller than the average narrowness of the skin side region in the narrowness evaluation test.

[0016] Preferably, the skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, the gap ratio of the non-skin side region in the gap ratio evaluation test used to quantitatively evaluate the proportion of the gaps in the predetermined region is smaller than the gap ratio of the skin side region in the gap ratio evaluation test.

[0017] Preferably, the hydrophilicity of the skin side layer is lower than that of the non-skin side layer.

[0018] Preferably, the skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, at least a portion of the fibers in the non-skin side region have higher hydrophilicity than the fibers in the skin side region, and a portion of the fibers in the non-skin side region are exposed on the skin side surface of the skin side region.

[0019] Preferably, the maximum thickness of the fibers in the skin side layer is greater than the maximum thickness of the fibers in the non-skin side layer.

[0020] Preferably, the potential coiled fibers of the skin side layer and the non-skin side layer are fibers composed of a single resin.

[0021] Preferably, the potential coiled fibers of the skin side layer and the non-skin side layer are fibers composed of polyethylene terephthalate.

[0022] Preferably, with the skin side layer and the non-skin side layer overlapping, the bending stiffness B in the KES method at the central portion of the skin side layer and the non-skin side layer in the length direction and at the central portion in the width direction is 1.2 gf·cm. 2 / cm or less.

[0023] Preferably, with the skin side layer and the non-skin side layer overlapping, the bending hysteresis 2HB in the KES method at the central portion of the skin side layer and the non-skin side layer in the length direction and at the central portion in the width direction is 0.93 gf·cm. 2 / cm or less.

[0024] Preferably, when the skin side layer and the non-skin side layer overlap, the linearity LC of the compression characteristics of the central portion in the length direction and the central portion in the width direction of the skin side layer and the non-skin side layer in the KES method is 0.6 or more.

[0025] Preferably, when the skin side layer and the non-skin side layer overlap, the compressive resilience RC of the central portion in the length direction and the central portion in the width direction of the skin side layer and the non-skin side layer in the KES method is 38.0% or more.

[0026] Preferably, with the skin side layer and the non-skin side layer overlapping, the compressive work WC in the KES method at the central portion of the skin side layer and the non-skin side layer in the length direction and at the central portion in the width direction is 1.3 gf·cm / cm. 2 above.

[0027] Preferably, when viewed along the thickness direction, the central portion of the absorbent article in the length direction and the central portion in the width direction is defined as a predetermined area. The weight of the predetermined area before absorbing distilled water is defined as the pre-absorption weight. The weight of the predetermined area after immersing it in distilled water for 60 seconds, pulling it out of the distilled water, and suspending it for 90 seconds is defined as the post-absorption weight. The value obtained by subtracting the pre-absorption weight from the post-absorption weight is defined as the absorbed weight of the distilled water. In this case, the value obtained by dividing the absorbed weight by the pre-absorption weight is 5 or more.

[0028] Preferably, in the state where the skin side layer and the non-skin side layer overlap, in an elongation test that measures the magnitude of the force used to elongate the length of the skin side layer and the non-skin side layer in the length direction to a length that is 1.3 times the length of the skin side layer and the non-skin side layer in the length direction, the value of the force measured in the 10th elongation test of the skin side layer and the non-skin side layer divided by the value of the force measured in the 1st elongation test of the skin side layer and the non-skin side layer is 50% or more.

[0029] Preferably, the air permeability resistance value of the overlapping state of the skin side layer and the non-skin side layer is less than 0.32 kPa·s / m.

[0030] Other features of this utility model will become clear from the description in this specification and the accompanying drawings.

[0031] Effects of the utility model

[0032] According to this invention, wrinkles are less likely to form on the skin side of absorbent materials. Attached Figure Description

[0033] Figure 1 This is a top view obtained by observing the sanitary napkin 1 from the skin side.

[0034] Figure 2 This is a schematic cross-sectional view of sanitary napkin 1 from the AA direction.

[0035] Figure 3 This is a diagram illustrating the structure of sanitary napkin 1.

[0036] Figure 4 This diagram illustrates the absorbent layer 10 of the sanitary napkin 1.

[0037] Figure 5 A is a schematic diagram showing a cross-section of the skin's lateral layer 2. Figure 5 B is a schematic diagram showing a cross-section of the non-skin side layer 3.

[0038] Figure 6 yes Figure 4 A magnified view of part X in the image.

[0039] Figure 7 yes Figure 6 A rough cross-sectional view of BB direction in the middle.

[0040] Figure 8 This is a diagram illustrating a sanitary napkin 1 that has been soaked with horse blood for 30 minutes.

[0041] Figure 9 This is a diagram illustrating the measurement area Y.

[0042] Figure 10 This diagram illustrates a summary of the evaluation method for the narrowness of gap Z.

[0043] Figure 11 This is a graph showing the results of the narrowness evaluation test and the void ratio evaluation test.

[0044] Figure 12 Figure A is a graph representing the measurement results of the bending characteristics of the absorber layer 10 based on the KES method. Figure 12 B is a graph representing the measurement results of the compressibility characteristics of the absorber layer 10 based on the KES method.

[0045] Figure 13 This is a graph showing the measurement results of the elongation test of the absorber layer 10.

[0046] Figure 14 This is a diagram illustrating a modified example of the sanitary napkin 100 according to this embodiment. Detailed Implementation

[0047] Based on the description in this specification and the accompanying drawings, at least the following matters become clear.

[0048] (Option 1)

[0049] An absorbent article, characterized in that, in its unfolded state, it has a length direction, a width direction, and a thickness direction, and comprises: a skin-side layer, the central portion of which is located closest to the skin in the width direction; a non-skin-side layer, located further away from the skin-side layer than the skin-side layer; and a liquid-impermeable outer layer, located further away from the non-skin-side layer than the non-skin-side layer, wherein the skin-side layer and the non-skin-side layer each have a plurality of fibers comprising potentially curled fibers, wherein the plurality of fibers in the skin-side layer and the non-skin-side layer are not fused together.

[0050] According to the absorbent material of Scheme 1, by ensuring that the fibers in the skin-side layer and the non-skin-side layer do not fuse together, the decrease in absorbency in both the skin-side layer and the non-skin-side layer can be reduced, or concerns about the skin-side layer and the non-skin-side layer becoming stiff can be alleviated. Furthermore, by having skin-side layer and non-skin-side layer with potentially shrinkable fibers, concerns about the skin-side layer and the non-skin-side layer becoming too stiff can be reduced, and even when the absorbent material is bent or compressed in its packaging state, or when force is applied to the absorbent material while wearing it, wrinkles are less likely to form on the skin-side of the absorbent material.

[0051] (Option 2)

[0052] According to the absorbent article described in Scheme 1, the non-skin side layer has a linear high-density portion with a higher fiber density than the surrounding area.

[0053] According to the absorbent article of Scheme 2, since the narrow gaps between the fibers can be arranged in a linear pattern, it is easy to utilize capillary action to promote the diffusion of absorbed excretions in the non-skin side layer. Furthermore, the density of the fibers around the high-density portion is lower than that of the fibers in the high-density portion itself, making the area around the high-density portion softer. Therefore, the area around the high-density portion in the non-skin side layer can easily cushion the force applied to the absorbent article, making it less likely for wrinkles to form on the skin side of the absorbent article due to the force applied.

[0054] (Option 3)

[0055] According to the absorbent article described in Scheme 1 or 2, the non-skin side layer has a recessed portion along the thickness direction on the skin side.

[0056] According to the absorbent material of Scheme 3, the concave portion becomes a part separated from the skin side layer, thus reducing concerns about excretions absorbed by the non-skin side layer returning to the skin side layer. Furthermore, compared to a flat skin side layer, the concave portion on the skin side layer makes it more deformable, allowing it to cushion the force applied to the absorbent material and reducing the likelihood of wrinkles forming on the skin side layer of the absorbent material.

[0057] (Option 4)

[0058] According to any of the embodiments 1 to 3, in the central part of the width direction, no adhesive is provided between the skin side layer and the non-skin side layer.

[0059] According to the absorbent article of Option 4, concerns about adhesives hindering the absorption of excrement can be reduced. Furthermore, by eliminating the need for adhesives between the skin-side layer and the non-skin-side layer, thus preventing the fibers of both layers from being fixed with adhesives, concerns about restricted deformation of the fibers in both layers can be reduced, and the hardening of the parts fixed with adhesives can be prevented. Therefore, concerns that the force applied to the absorbent article is concentrated on the skin-side layer and the parts of the non-skin-side layer fixed with adhesives can be reduced.

[0060] (Option 5)

[0061] According to the absorbent article described in any of Schemes 1 to 4, the thickness of the skin side layer is greater than the thickness of the non-skin side layer.

[0062] According to Option 5, the absorbent material, compared to a material where the skin-side layer is thinner than the non-skin-side layer, allows the non-skin-side layer to be further away from the wearer's skin. This reduces concerns about excretions temporarily absorbed by the non-skin-side layer returning to the skin-side layer and improves the feel against the wearer's skin. Furthermore, compared to a material where the skin-side layer is thinner than the non-skin-side layer, the skin-side layer is less prone to bending, thus reducing the likelihood of wrinkles forming on the skin-side of the absorbent material.

[0063] (Option 6)

[0064] According to the absorbent article described in any of Schemes 1 to 5, the skin side layer has a gap formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, the average narrowness of the non-skin side region in the narrowness evaluation test used to quantitatively evaluate the narrowness of the gap is smaller than the average narrowness of the skin side region in the narrowness evaluation test.

[0065] According to the absorbent material of Scheme 6, it is easy to utilize capillary action to introduce excretions from the skin-side area to the non-skin-side area, and it is easy for excretions absorbed from the skin-side layer to diffuse to the non-skin-side. Therefore, it is easy to promote the diffusion of excretions from the skin-side layer to the non-skin-side layer, which can reduce concerns about excretion residue on the surface of the skin-side layer. In addition, the narrower the gaps formed by the fibers, the denser the fiber structure, the more difficult the fibers are to move, and the easier it is for the fibers to recover their shape when force is applied to the fibers. Therefore, compared with the case where the average narrowness of the skin-side area is smaller than the average narrowness of the non-skin-side area, the average narrowness of the skin-side area is larger than the average narrowness of the non-skin-side area, which makes it less likely for the fiber structure of the skin-side area to become dense, making it easier for the fibers to move. As a result, the recovery of the fibers when force is applied is better, thus reducing concerns about wrinkles and creases forming on the skin-side area compared to the non-skin-side area. Therefore, it is easy to reduce wrinkles and creases generated on the skin-side of the absorbent material.

[0066] (Option 7)

[0067] According to the absorbent article described in any of the schemes 1 to 6, the skin side layer has voids formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, the void ratio of the non-skin side region in the void ratio evaluation test used to quantitatively evaluate the proportion of voids in the predetermined region is smaller than the void ratio of the skin side region in the void ratio evaluation test.

[0068] According to the absorbent material of Scheme 7, it is easy to utilize capillary action to introduce excretions into the non-skin side area compared to the skin side area. This facilitates the diffusion of excretions absorbed from the skin side layer to the non-skin side layer, thus reducing concerns about excretion residue on the skin side layer surface. Furthermore, the smaller the proportion of voids formed by the fibers, the denser the fiber structure, the more difficult the fibers are to move, and the easier it is for the fibers to regain their shape when force is applied. Therefore, compared to a situation where the proportion of voids in the skin side area is smaller than that in the non-skin side area, a larger proportion of voids in the skin side area makes it less likely for the fiber structure in the skin side area to become denser, facilitating fiber movement. This results in better resilience when force is applied to the fibers, reducing concerns about wrinkles and creases forming on the skin side area compared to the non-skin side area. Therefore, it is easier to reduce wrinkles and creases on the skin side of the absorbent material.

[0069] (Option 8)

[0070] According to the absorbent articles described in any of Schemes 1 to 7, the hydrophilicity of the skin side layer is lower than that of the non-skin side layer.

[0071] According to the absorbent material of scheme 8, it is easy to promote the diffusion of excrement absorbed in the skin side layer to the non-skin side layer, thus reducing concerns about excrement remaining on the surface of the skin side layer and reducing concerns about leakage of excrement from the absorbent material.

[0072] (Option 9)

[0073] According to any of the embodiments 1 to 8, the absorbent article has a skin-side layer with a gap formed by the plurality of fibers. When the skin-side layer is divided into three equal parts along the thickness direction and the region closest to the skin side is designated as the skin-side region, the region closest to the non-skin side is designated as the non-skin-side region, and the region between the skin-side region and the non-skin-side region is designated as the intermediate region, at least a portion of the fibers in the non-skin-side region have a higher hydrophilicity than the fibers in the skin-side region, and a portion of the fibers in the non-skin-side region are exposed on the skin-side surface of the skin-side region.

[0074] According to the absorbent material of scheme 9, the fibers of the exposed non-skin side area can easily introduce excrement absorbed from the skin side towards the non-skin side area, which can easily promote the diffusion of excrement in the non-skin side area and facilitate the diffusion of excrement from the skin side layer to the non-skin side layer, thereby reducing concerns about excrement residue on the surface of the skin side area.

[0075] (Option 10)

[0076] According to the absorbent article described in any of Schemes 1 to 9, the maximum value of the thickness of the fibers in the skin side layer is greater than the maximum value of the thickness of the fibers in the non-skin side layer.

[0077] According to the absorbent material of Scheme 10, the coarser the fibers, the larger the gaps formed by the fibers. This makes it easier for the gaps formed by the fibers in the non-skin side layer to be narrower compared to those in the skin side layer. Therefore, it is easier to utilize capillary action to introduce excretions from the skin side layer to the non-skin side layer, thus improving diffusion in the non-skin side layer. Conversely, the finer the fibers, the narrower the gaps formed by the fibers, the denser the fiber structure, the more difficult the fibers are to move, and the easier it is for the fibers to regain their shape when force is applied. Therefore, compared to a situation where the fibers in the skin side area are thinner than those in the non-skin side area, having coarser fibers in the skin side area makes it less likely for the fiber structure in the skin side area to become denser, facilitating fiber movement. This results in better resilience when force is applied to the fibers, reducing concerns about wrinkles and creases forming in the skin side area compared to the non-skin side area, and thus reducing wrinkles and creases on the skin side of the absorbent material.

[0078] (Option 11)

[0079] According to the absorbent articles described in any of Schemes 1 to 10, the potential coiled fibers of the skin side layer and the non-skin side layer are fibers composed of a single resin.

[0080] According to the absorbent article of Scheme 11, the physical properties of the skin-side layer and non-skin-side layer, which utilize potentially curled fibers made of a single-component resin, are easily made uniform, thus preventing wrinkles from forming on the skin-side of the absorbent article. Furthermore, by using a single-component resin in both the skin-side layer and non-skin-side layer, the number of components in the manufacture of the absorbent article can be reduced, thereby reducing manufacturing costs and improving the workability of manufacturing and recycling.

[0081] (Option 12)

[0082] According to the absorbent article described in any of Schemes 1 to 11, the potential curled fibers of the skin side layer and the non-skin side layer are respectively composed of polyethylene terephthalate fibers.

[0083] According to the absorbent article of Scheme 12, the physical properties of the skin-side layer and non-skin-side layer, which utilize potentially shrinkable fibers composed of polyethylene terephthalate, tend to become uniform, thus reducing the likelihood of wrinkles forming on the skin-side of the absorbent article. Furthermore, by using polyethylene terephthalate in both the skin-side layer and non-skin-side layer, the number of components in the manufacture of the absorbent article can be reduced, thereby reducing manufacturing costs and improving the workability of manufacturing and recycling.

[0084] (Option 13)

[0085] According to the absorbent article described in any of Schemes 1 to 12, with the skin-side layer and the non-skin-side layer overlapping, the bending stiffness B in the KES method at the central portion of the skin-side layer and the non-skin-side layer in the length direction and at the central portion in the width direction is 1.2 gf·cm. 2 / cm or less.

[0086] According to Scheme 13, the absorbent material has a flexural stiffness B ratio of 1.2 gf·cm compared to the skin-side layer and the non-skin-side layer. 2 Compared to a size larger than 6cm, it can make absorbent items softer, thus reducing concerns about wrinkles forming on absorbent items.

[0087] (Option 14)

[0088] According to the absorbent article described in any of Schemes 1 to 13, with the skin-side layer and the non-skin-side layer overlapping, the bending hysteresis 2HB at the central portion in the length direction and the central portion in the width direction of the skin-side layer and the non-skin-side layer in the KES method is 0.93 gf·cm. 2 / cm or less.

[0089] According to Scheme 14, the absorbent material exhibits a bending hysteresis of 2HB compared to that of the skin-side layer and the non-skin-side layer, which is 0.93 gf·cm. 2 Compared to cases with a size of / cm, it is easier to restore the skin-side and non-skin-side layers that have deformed while being worn to their original shape, reducing concerns about wrinkles forming in absorbent items.

[0090] (Option 15)

[0091] According to any of the embodiments 1 to 14, the linearity LC of the compressibility of the absorbent article in the KES method, in a state where the skin side layer and the non-skin side layer overlap, is 0.6 or more at the central portion of the skin side layer and the non-skin side layer in the length direction and the central portion in the width direction.

[0092] According to the absorbent material of Scheme 15, compared with the case where the linearity LC ratio of the compression properties of the skin side layer and the non-skin side layer is smaller than 0.6, the skin side layer and the non-skin side layer can be made more resistant to compression, thus reducing the deformation of the skin side layer and the non-skin side layer and reducing concerns about wrinkles forming in the absorbent material.

[0093] (Option 16)

[0094] According to any of the embodiments 1 to 15, the absorbent article, in a state where the skin side layer and the non-skin side layer overlap, has a compression resilience RC of 38.0% or more in the KES method at the central portion of the skin side layer and the central portion of the non-skin side layer in the length direction and the central portion in the width direction.

[0095] According to the absorbent material of Scheme 16, compared with the compression resilience of the skin-side layer and the non-skin-side layer being less than 38%, it is easier to restore the shape of the skin-side layer and the non-skin-side layer under the wearing condition, thus reducing concerns about wrinkles forming in absorbent materials.

[0096] (Option 17)

[0097] According to the absorbent article described in any of Schemes 1 to 16, with the skin-side layer and the non-skin-side layer overlapping, the compressive work WC in the KES method at the central portion of the skin-side layer and the central portion of the non-skin-side layer in the length direction and the width direction is 1.3 gf·cm / cm. 2 above.

[0098] According to Scheme 17, the compressive work in the KES method at the central portion in the length direction and the central portion in the width direction of the absorbent article relative to the skin side layer and non-skin side layer is less than 1.3 gf·cm / cm. 2Compared to other layers, the skin side layer and the non-skin side layer are easier to compress and have better compression recovery, making it easier for the skin side layer and the non-skin side layer to regain their shape, thus reducing concerns about wrinkles forming on absorbent items.

[0099] (Option 18)

[0100] According to any of the schemes 1 to 17, when viewed along the thickness direction, the central part of the absorbent article in the length direction and the central part in the width direction is defined as a predetermined area. The weight of the predetermined area before absorbing distilled water is defined as the pre-absorption weight. The weight of the predetermined area after immersing it in distilled water for 60 seconds, pulling it out of the distilled water, and suspending it for 90 seconds is defined as the post-absorption weight. The value obtained by subtracting the pre-absorption weight from the post-absorption weight is defined as the absorbed weight of the distilled water. At this time, the value obtained by dividing the absorbed weight by the pre-absorption weight is 5 or more.

[0101] According to Scheme 18, the absorbent article can ensure the liquid absorption function of the absorbent article and reduce concerns about wrinkles forming in the absorbent article, compared to cases where the value obtained by dividing the absorbed weight by the weight before absorption is less than 5.

[0102] (Option 19)

[0103] According to any of the embodiments 1 to 18, in an elongation test in which the force used to elongate the length of the skin side layer and the non-skin side layer in the length direction to a length that is 1.3 times the length of the skin side layer and the non-skin side layer in the length direction is measured, the value of the force measured in the 10th elongation test of the skin side layer and the non-skin side layer is divided by the value of the force measured in the 1st elongation test of the skin side layer and the non-skin side layer, and the result is 50% or more.

[0104] According to Scheme 19, the absorbent article can be configured such that, compared to cases where the value obtained by dividing the magnitude of the force measured in the 10th elongation test by the magnitude of the force measured in the 1st elongation test is less than 50%, the value obtained by dividing the magnitude of the force measured in the 10th elongation test by the magnitude of the force measured in the 1st elongation test is more than 50%, thereby reducing damage to the skin side layer and non-skin side layer even when worn, and easily following the shape and movement of the wearer's body.

[0105] (Option 20)

[0106] According to any of the embodiments 1 to 19, the absorbent article in which the skin side layer and the non-skin side layer overlap has an air permeability resistance value of 0.32 kPa·s / m or less.

[0107] According to Scheme 20, the breathability of the absorbent material can be improved compared to the case where the air resistance value is greater than 0.32 kPa·s / m when the skin side layer and non-skin side layer overlap, thus reducing the discomfort of the wearer.

[0108] ===Implementation Methods===

[0109] As an absorbent article of this invention, a sanitary napkin 1 (hereinafter also referred to as "sanitary napkin 1") will be used as an example to describe the embodiments. However, the absorbent article of this invention may also be adult or infant underwear-type disposable diapers, strip-type disposable diapers, menstrual panties, menstrual sanitary napkins, incontinence pads, absorbent pads, animal disposable diapers, absorbent sheets, fresh absorbent pads (Japanese: ドリップシート), etc. Furthermore, in the case of fresh absorbent pads, etc., the "wearing state" in the following embodiments will be referred to as the "use state," and the wearer will be referred to as the "user, etc." Hereinafter, the wearing state will also be referred to as the "use state," and the wearer will also be referred to as the "user, etc."

[0110] <<<Structure of Sanitary Napkin 1>>>

[0111] Figure 1 This is a top view of the sanitary napkin 1 (hereinafter also referred to as "sanitary napkin") viewed from the skin side. Figure 2 This is a schematic cross-sectional view of sanitary napkin 1 from the AA direction. Figure 3 This diagram illustrates the structure of sanitary napkin 1. Sanitary napkin 1 has mutually orthogonal longitudinal, width, and thickness directions. The side in the thickness direction that contacts the wearer's skin is called the skin side, and the opposite side is called the non-skin side. The skin side in the thickness direction is the side that receives excrement (liquid) when worn, and is also called the "absorbent side." The non-skin side in the thickness direction is the opposite side of the absorbent side, and is also called the "non-absorbent side." Figure 1 The center line CC shown indicates the center (central position) in the width direction of sanitary napkin 1.

[0112] Sanitary napkins 1 have a skin-friendly side layer 2, a non-skin-friendly side layer 3, a backing (outer layer) 4, and side sheets 5. For example Figure 3 As shown, the sanitary napkin 1 is constructed by sequentially overlapping the side sheet 5, the skin-side layer 2, the non-skin-side layer 3, and the backing sheet 4 in the thickness direction, starting from the skin side. The overlapping components along the thickness direction are fixed together using adhesives such as hot melt adhesives.

[0113] The skin-side layer 2 is a skin-side sheet located at the center of the sanitary napkin 1 in the width direction, closest to the skin. It is an absorbent component that abuts against the discharge opening and receives excrement discharged from the opening when the sanitary napkin 1 is worn. The skin-side layer 2 is approximately rectangular in shape, with its length L2 being longer than its width W2. By positioning the skin-side layer 2 at the crotch area of ​​the wearer when the sanitary napkin 1 is worn, it can absorb excrement even after the sanitary napkin 1 has absorbed it, allowing the absorbed excrement to diffuse towards the non-skin-side layer 3. Therefore, it can reduce discomfort caused to the wearer by leakage of excrement from the sanitary napkin 1 or localized retention of excrement on the surface of the skin-side layer 2.

[0114] The non-skin side layer 3 is a non-skin side layer located between the skin side layer 2 and the backing sheet 4 in the thickness direction. When viewed from above, the non-skin side layer 3 is slightly smaller than the skin side layer 2. The non-skin side layer 3 is approximately rectangular in shape, with its length L3 being longer than its width W3. The non-skin side layer 3 is an absorbent component that absorbs and retains the excrement absorbed by the skin side layer 2. By placing the non-skin side layer 3 at the crotch area of ​​the wearer when the sanitary napkin 1 is worn, it absorbs excrement even after the sanitary napkin 1 has absorbed it, allowing the excrement to diffuse within the non-skin side layer 3. Therefore, it reduces discomfort caused to the wearer by leakage of excrement from the sanitary napkin 1 or localized retention of excrement on the surface of the skin side layer 2.

[0115] Skin side layer 2 and non-skin side layer 3 are respectively composed of potential coiled fiber 2f and potential coiled fiber 3f (refer to...) Figure 5 The nonwoven fabric (nonwoven sheet) is composed of skin-side layer 2 and non-skin-side layer 3 in this embodiment. The nonwoven fabric is formed only by potentially curled fibers (100% potentially curled fibers). However, for the layers (nonwoven fabric) constituting skin-side layer 2 and non-skin-side layer 3, in addition to using potentially curled fibers, fibers composed of polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters (PET, PBT), polyamides, and their composite fibers can also be used. In addition, hydrophilic fibers such as rayon, pulp, and cotton can also be used. Hereinafter, potentially curled fiber 2f will be simply referred to as "fiber 2f" and potentially curled fiber 3f will be simply referred to as "fiber 3f".

[0116] "Nonwoven fabric" refers to a fabric formed in which fibers are oriented in one direction or randomly within a sheet, web, or pad, and are bonded together by interlacing, and / or welding, and / or bonding (JIS L0222:2001 Nonwoven Fabric Terminology 101). In other words, nonwoven fabric is a fabric that is integral without weaving fibers, and is a sheet with a breaking strength of 5 [N] / 25 mm or higher. Breaking strength can be measured using known methods, for example, using a tensile testing machine (manufactured by Shimadzu Corporation: AUTOGRAPH, AGS-1kNG) equipped with a force sensor with a maximum load capacity of 50 N. When measuring the breaking strength of the nonwoven sheet, one chuck holds the front end of one side of the nonwoven sheet in the long or short direction, and another chuck holds the other side of the nonwoven sheet. Using a tensile testing machine, the two chucks are stretched at a certain speed (e.g., 100 mm / min) with the spacing between them widened, and the load applied to the two chucks is measured. The load at which the nonwoven fabric breaks is defined as the breaking strength.

[0117] Examples of nonwoven fabrics include: nonwoven fabrics obtained by meltblowing (meltblown nonwoven fabric), nonwoven fabrics obtained by electrospinning (electrospinned nonwoven fabric), nonwoven fabrics obtained by spunbonding (spunbonded nonwoven fabric), nonwoven fabrics manufactured by hot air method (hot air nonwoven fabric), nonwoven fabrics manufactured by hydroentangling method (spunlace nonwoven fabric), or nonwoven fabrics manufactured by needle punching method (needle-punched nonwoven fabric), or laminates of two or more of these nonwoven fabrics, or laminates of these nonwoven fabrics and nonwoven fabrics other than these nonwoven fabrics, or other materials. In this embodiment, the skin-side layer 2 and the non-skin-side layer 3 are both hydroentangled nonwoven fabrics formed by interweaving fibers with water flow without using an adhesive.

[0118] In this embodiment, the nonwoven fabric sheet of the skin-side layer 2 of the sanitary napkin 1 is formed by hydroentangling through the following process.

[0119] (a) First, hydrophilic fibers 2fb (at least local fibers 2f forming the non-skin side region Rd described later) are processed using a combing machine or the like to form a non-skin side fiber mesh with a combed mesh or the like.

[0120] (b) Next, while conveying the non-skin side fiber mesh, the skin side fiber mesh, which has been processed by a combing machine or the like to form a combed mesh, is supplied to the non-skin side fiber mesh and stacked to obtain a stacked mesh.

[0121] (c) By applying high-pressure water jet or other water jet treatment from the skin side to the non-skin side in the thickness direction of the laminated mesh, the fibers between the fiber layers and the fibers of each mesh interweave with each other to obtain a laminated body.

[0122] (d) Finally, the laminate is placed in a dryer and heated to a temperature at which the potentially shrinkable fibers can shrink, thereby obtaining an integrated nonwoven sheet (skin-side layer 2). This nonwoven sheet has voids formed by multiple fibers 2f.

[0123] The non-skin side layer 3 of the sanitary napkin 1 in this embodiment is also formed using the same method as the non-skin side layer 2. However, the non-skin side layer 3 differs from the skin side layer 2 in that it does not use hydrophobic fibers, but instead uses a mesh of only hydrophilic fibers 3f.

[0124] Potentially crimped fibers 2f and 3f are fibers that have been crimped into a helical shape by heat treatment. Examples of potentially crimped fibers include parallel composite fibers with high-shrinkage and low-shrinkage components arranged side-by-side, and core-sheath type composite fibers with the high-shrinkage component as the core and the low-shrinkage component as the sheath, where the centers of gravity of the two components do not overlap at a single point. When a potentially crimped fiber is crimped, it may, for example, crimp in a coiled manner.

[0125] As multiple resins with different heat shrinkage rates or heat expansion rates for forming potential shrinkable fibers 2f and 3f, there are no particular limitations on their use, as long as they are combinations of resins with different heat shrinkage rates or heat expansion rates. Combinations of similar or single resins, or combinations of different types of resins, are also acceptable. Specific examples of combinations of resins with different heat shrinkage rates or heat expansion rates for forming the potential shrinkable fiber include combinations of polyester resins and combinations of polyamide resins.

[0126] In this embodiment, the nonwoven fabric of the skin-side layer 2 and the non-skin-side layer 3 is a combination of polyester resins (single-component resins), specifically, a potentially shrinkable fiber using a combination of polyethylene terephthalate (PET) and modified PET. Furthermore, the modified PET is obtained by copolymerizing a diol component other than ethylene glycol or a dicarboxylic acid component other than terephthalic acid with ethylene glycol and terephthalic acid, which are components of PET, as a small amount of the modified PET. Specific examples of diol components other than ethylene glycol include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, cyclohexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene ether glycol, etc. Specific examples of dicarboxylic acid components other than terephthalic acid include isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, etc. Furthermore, a web-forming unit, such as a carding machine, is used to form a web composed of potentially shrinkable fibers of a combination of PET and modified PET. This web is then spun into a nonwoven fabric state by hydroentangling the fibers, and heated to a predetermined temperature to cause the potentially shrinkable fibers to curl. This process produces a nonwoven fabric consisting of a skin-side layer 2 and a non-skin-side layer 3. Consequently, the area weight per unit area of ​​the potentially shrinkable fibers in the heated nonwoven fabric is greater than that in the unheated state. In other words, the nonwoven fabric shrinks due to the curling of the potentially shrinkable fibers, increasing the area weight per unit area of ​​the fibers.

[0127] The skin-side layer 2 and the non-skin-side layer 3 are respectively absorbent layers 10 with predetermined thickness that are permeable to liquid, have liquid absorption function and liquid retention function. Figure 4 This diagram illustrates the absorbent layer 10 of the sanitary napkin 1. In the sanitary napkin 1, the skin-side layer 2 is the skin-side sheet that contacts the wearer's skin. It is the component that initially receives excrement when worn, and it is the component that absorbs the received excrement within the skin-side layer 2 and allows the excrement to permeate towards the non-skin side. The non-skin-side layer 3 is the component that absorbs and retains the excrement that permeates from the skin-side layer 2.

[0128] like Figure 5 As shown, the skin side layer 2 and the non-skin side layer 3 each have a gap formed by multiple fibers (potentially coiled fibers) 2f and 3f. Figure 5 A is a schematic cross-section of the lateral layer 2 of the skin. Figure 5B is a schematic cross-section of the non-skin side layer 3, and the dimensions may not be accurate. Furthermore, the gaps in the skin side layer 2 and the non-skin side layer 3 can be gaps between discontinuous fibers (multiple fibers), gaps formed by a continuous fiber bending or spiraling, or gaps formed by combinations of the above. Gaps formed by multiple fibers 2f and 3f refer to spaces or regions in the skin side layer 2 and the non-skin side layer 3 where multiple fibers 2f and 3f are not present. Moreover, gaps are not only spaces surrounded or closed by fibers 2f and 3f, but can also be spaces at least partially open within gaps formed by fibers 2f and 3f.

[0129] The skin-side layer 2 and the non-skin-side layer 3, each containing potentially curled fibers 2f and 3f respectively, form a spiral shape by intertwining the fibers 2f and 3f with each other through the curling. For example, the gaps between fibers 2f and 3f are further reduced due to the curling or the entry of other fibers between fibers 2f and 3f where the distance is shortened. Therefore, the gaps formed by fibers 2f and 3f containing potentially curled fibers are smaller than the gaps formed by multiple fibers in a typical nonwoven fabric formed by non-curled fibers.

[0130] Furthermore, the potential coiled fibers 2f and 3f, respectively located in the skin-side layer 2 and the non-skin-side layer 3, do not readily absorb liquid. For example, in fibers such as pulp fibers, the fiber thickness increases when liquid (excrement) is absorbed, but even when the potential coiled fibers 2f and 3f in the skin-side layer 2 and the non-skin-side layer 3 come into contact with liquid, the inner side of the fibers does not readily absorb liquid. Therefore, in the skin-side layer 2 and the non-skin-side layer 3, even when the sanitary napkin 1 has absorbed excrement during wear, the thickness of the potential coiled fibers 2f and 3f in the skin-side layer 2 and the non-skin-side layer 3 does not readily increase. Because the thickness of the fibers does not readily increase, the size of the gaps formed by the fibers 2f and 3f does not readily decrease, and the gaps do not readily flatten. Thus, in the skin-side layer 2 and the non-skin-side layer 3, liquid (excrement) can be retained in the gaps formed by the fibers 2f and 3f. Therefore, the skin-side layer 2 and the non-skin-side layer 3 are layers that allow liquid to pass through, and layers that can absorb and retain liquid. In addition, the skin-side layer 2 and the non-skin-side layer 3 are non-woven fabric sheets formed by fibers 2f and 3f, respectively. They have gaps formed by fibers 2f and 3f, so they have excellent breathability, which can reduce the stuffiness and roughness of the wearer and improve the comfort of wearing them.

[0131] As described above, the potential crimped fibers 2f in the skin-side layer 2 are a combination of PET and modified PET, and fibers of the same thickness are used throughout the entire area. In this embodiment, the thickness of the potential crimped fibers 2fa is set to 2.2 dtex. Furthermore, the average narrowness of the voids in the skin-side layer 2 is 104 μm. Also, the proportion of voids in the skin-side layer 2 (the proportion of the area in the skin-side layer 2 without fibers 2f) is 94%. The weight per unit area of ​​the skin-side layer 2 is approximately 170 gsm. Additionally, it is preferable that hydrophobic fibers are used on the skin side and hydrophilic fibers are used on the non-skin side in the skin-side layer 2.

[0132] The potential shrinkable fibers 3f in the non-skin side layer 3 are all potential shrinkable fibers composed of a combination of PET and modified PET, and fibers of the same thickness are used throughout the entire thickness direction. The thickness of the potential shrinkable fibers 3f in the non-skin side layer 3 of this embodiment is set to 2.2 dtex. The area weight of the non-skin side layer 3 is approximately 120 gsm. Preferably, the area weight of the fibers 3f in the non-skin side layer 3 is 80 gsm or more and 200 gsm or less.

[0133] The non-skin side layer 3 has a linear high-density section DH with a higher fiber density than the surrounding area (low-density section DL) and a low-density section DL with a lower fiber density than the high-density section DH. The high-density section DH is a section that is thinner than the surrounding area (low-density section DL) and the fibers are not fused together.

[0134] The backing sheet 4 is a liquid-impermeable sheet (outer layer) positioned on the non-skin side of the skin-side layer 3. Examples of liquid-impermeable sheets include polyethylene (PE) resin films. The side sheets 5 are sheets extending outward from both sides of the skin-side layer 2 in the width direction. Examples of side sheets 5 include hydrophobic hot-air nonwoven fabrics and hydrophobic spunbond nonwoven fabrics.

[0135] Additionally, the sanitary napkin 1 has a pair of wings 1w extending outward from approximately the center in the length direction towards the width direction. The wings 1w are formed by side panels 5 and a backing panel 4. Alternatively, the sanitary napkin 1 may not necessarily have the wings 1w. If the sanitary napkin 1 does not have the wings 1w, it may or may not have the side panels 5.

[0136] In addition, the sanitary napkin 1 has a compression section 20 formed by the skin side layer 2 and the non-skin side layer 3 being recessed along their thickness direction. The compression section 20 can be used to fix the position of the skin side layer 2 and the non-skin side layer 3, or to improve the liquid spreadability of the sanitary napkin 1.

[0137] In the compression section 20, the sanitary napkin 1 is thinner than its surroundings, and the fiber density of the sanitary napkin 1 (skin-side layer 2 and non-skin-side layer 3) is higher. These comparisons are preferably made using known methods. Examples of methods for comparing the thickness of the sanitary napkin 1 include visual comparison, using a dial-type thickness gauge ID-C1012C manufactured by Mitutoyo Co., Ltd., or an equivalent instrument to obtain the thickness of the target area, for example, at 3.0 gf / cm². 2 A method for comparing values ​​measured by applying pressure. As an example of comparing the density of the sanitary napkin 1, a method based on comparing images obtained by magnifying a cross-section of the sanitary napkin 1 cut along its thickness direction using an electron microscope or similar instrument. Furthermore, the shape of the compression section 20 is not limited to... Figure 1 The shape shown. For example, it could also be a shape in which multiple point-like compression sections are discretely arranged.

[0138] <<<About Absorption Layer 10>>>

[0139] As described above, the sanitary napkin 1 has an absorbent layer 10 (skin-side layer 2, non-skin-side layer 3), a backing sheet 4, and side sheets 5 (see reference). Figure 3 (etc.). The sanitary napkin 1 has a skin-side layer 2 located at the center of its width, closest to the skin, a non-skin-side layer 3 located further away from the skin-side layer 2, and a liquid-impermeable backing sheet (outer layer) 4 located further away from the skin-side layer 3. The skin-side layer 2 has a plurality of fibers 2f containing potentially curled fibers, and the non-skin-side layer 3 has a plurality of fibers 3f containing potentially curled fibers. Furthermore, the fibers 2f and 3f in the skin-side layer 2 and the non-skin-side layer 3 are not fused together. That is, the fibers 2f of the skin-side layer 2 and the fibers 3f of the non-skin-side layer 3 are not fused together based on the melting of fibers 2f and 3f, and the skin-side layer 2 and the non-skin-side layer 3 are non-woven sheets formed by each fiber 2f and 3f being highly intertwined by their own individual fibers. The skin side layer 2 and the non-skin side layer 3 are able to retain excrement (liquid) in the gaps formed by multiple fibers 2f and 3f, respectively. Therefore, the skin side layer 2 and the non-skin side layer 3 are absorbent bodies (absorbent layers) that can absorb excrement.

[0140] If fibers 2f of the skin-side layer 2 and fibers 3f of the non-skin-side layer 3 are fused together, the fused portion becomes a compressed void. Therefore, there are concerns about decreased absorbency or hardening of the skin-side layer 2 and non-skin-side layer 3 due to the fusion of fibers 2f and 3f. Furthermore, if the skin-side layer 2 and non-skin-side layer 3 harden, wrinkles are likely to form on the skin-side of the absorbent material when it is bent, compressed in its packaging, or when force is applied to the absorbent material due to the wearer's weight or movements. Wrinkles on the skin-side of the absorbent material raise concerns that not only will the aesthetics of the absorbent material be reduced, but also that excrement may flow along the wrinkles or the absorbent material may bend in ways contrary to its intended purpose, leading to leakage.

[0141] In contrast, in sanitary napkin 1, multiple fibers 2f and 3f are not highly fused together in the skin-side layer 2 and the non-skin-side layer 3. This reduces the likelihood of decreased absorbency in both the skin-side layer 2 and the non-skin-side layer 3. Furthermore, concerns about the skin-side layer 2 and the non-skin-side layer 3 becoming stiff due to the fusion of fibers 2f and 3f are reduced. Moreover, since the skin-side layer 2 is formed of fibers 2f containing potentially curled fibers, and the non-skin-side layer 3 is formed of fibers 3f containing potentially curled fibers, concerns about excessive stiffness of the absorbent layer 10 can be reduced by utilizing the softness of fibers 2f and 3f. Because the skin-side layer 2, located closest to the skin, contains fibers 2f containing potentially curled fibers, wrinkles are less likely to form on the skin-side surface of the skin-side layer 2. In other words, because the fibers 2f containing potentially curled fibers have a spiral (coiled) fiber structure, the skin-side layer 2 is made soft and elastic. Therefore, compared to sheets or layers that do not contain potentially shrinkable fibers, the skin-side layer 2 is elastic and less prone to wrinkles or creases. Similarly, in the non-skin-side layer 3, because the fibers 3f containing potentially shrinkable fibers have a spiral (coiled) structure, the non-skin-side layer 3 is easily made soft and elastic. For a sanitary napkin 1 with these skin-side layers 2 and 3, even when the sanitary napkin 1 is bent (folded) or compressed in its packaged state, or when force is applied to the sanitary napkin 1 due to the wearer's body shape or weight, the fibers 2f and 3f easily absorb the force applied to the sanitary napkin 1, thus preventing wrinkles from forming on the skin-side of the sanitary napkin 1. By preventing wrinkles from forming on the skin-side of the sanitary napkin 1, the aesthetics of the sanitary napkin 1 can be improved, or concerns about leakage of excrement from the sanitary napkin 1 can be reduced. Furthermore, it can reduce the following concerns: when worn, the folds created by the sanitary napkin 1 become the starting point for bending, causing the sanitary napkin 1 to bend at a position contrary to the wearer's intention, which may cause discomfort to the wearer.

[0142] Furthermore, it is preferable that the skin-side layer 2 is located at the center of the sanitary napkin 1 in the width direction, closest to the skin, and that no sheet member is provided in the center of the sanitary napkin 1 in the width direction, at a position closer to the skin than the skin-side layer 2. However, a sheet member that is significantly thinner than the absorbent layer 10 (skin-side layer 2 and non-skin-side layer 3) may be provided in the center of the width direction, closer to the skin than the skin-side layer 2. As for the sheet member that is significantly thinner than the absorbent layer 10, it is sufficient to have a sheet member with a unit area weight of less than 1 / 10 of the unit area weight of the absorbent layer 10 (skin-side layer 2 and non-skin-side layer 3). If such a sheet member is significantly thinner than the absorbent layer 10, then even when force is applied to the sanitary napkin 1 in the wearing or packaged state, it is less likely that wrinkles or creases will form on the thinner sheet member located closer to the skin than the skin-side layer 2. Therefore, in the case of a sheet component in which the absorbent layer 10 (skin side layer 2 and non-skin side layer 3) fibers 2f and 3f are provided in the central part of the width direction of the sanitary napkin 1 at a position closer to the skin side than the skin side layer 2, the skin side layer 2 is provided as a component "located at the position closest to the skin side".

[0143] Furthermore, it is preferable that the potential shrinkage fibers 2f and 3f of the skin side layer 2 and the non-skin side layer 3 are each composed of a single-component resin. In particular, it is more preferable that each potential shrinkage fiber 2f and 3f is composed of polyethylene terephthalate (PET).

[0144] The skin-side layer 2 and non-skin-side layer 3, each composed of a single-component resin, particularly polyethylene terephthalate (PET), with its potential shrinkable fibers 2f and 3f, are easily made into components with uniform physical properties. Therefore, the nonwoven fabric of the skin-side layer 2 and non-skin-side layer 3 is easily made into a sheet component with approximately uniform properties, thus reducing the likelihood of wrinkles forming on the skin-side of the sanitary napkin 1. Furthermore, by using a single-component resin (e.g., polyethylene terephthalate) in the skin-side layer 2 and non-skin-side layer 3, the number of components in the manufacture of the sanitary napkin 1 can be reduced, thereby reducing the manufacturing cost of the sanitary napkin 1 or improving the workability of manufacturing and recycling.

[0145] Furthermore, preferably, the non-skin side layer 3 has a linear high-density portion DH with a higher density of fibers 3f than the surrounding area. It also has a low-density portion DL with a lower density of fibers 3f than the high-density portion DH. As described above, in the non-skin side layer 3, the fibers 3f are not fused together and are thinner than the surrounding area (low-density portion DL). Figure 6 yes Figure 4 A magnified view of part X in the image. Figure 7 yes Figure 6A rough cross-sectional view of BB direction in the middle.

[0146] The narrower the gaps between fibers, the easier it is for excrement (liquid) to diffuse. Therefore, in the high-density layer DH, compared to the case where fibers are fused together, by preventing fibers 3f from fusing together, concerns about hindering the diffusion of absorbed liquid (excrement) can be reduced. Furthermore, the non-skin side layer 3 is an absorbent material formed from a nonwoven fabric with potentially shrinkable fibers. Thus, the interweaving of multiple fibers maintains its shape, making it easier to maintain the shape of the gaps formed by the multiple fibers. Moreover, concerns that pulp fibers might absorb liquid and expand, flattening the gaps formed by fibers 3f, can be reduced. Therefore, in the non-skin side layer 3 after absorbing liquid (excrement), it is easy to maintain the gaps between fibers 3f, and it is easy to utilize the capillary phenomenon based on the high-density layer DH to promote the introduction of liquid into the high-density layer DH, facilitating the diffusion of absorbed liquid within the non-skin side layer 3. Furthermore, by facilitating diffusion within the non-skin side layer 3, concerns can be reduced regarding the following: when the sanitary napkin 1 is worn, the excrement absorbed by it remains in the skin side layer 2, or the excrement that temporarily reaches the non-skin side layer 3 returns to the skin side layer 2, causing discomfort to the wearer. Additionally, the high-density portion DH is surrounded by a low-density portion DL, where the fiber density is lower than that of the high-density portion. The low-density portion DL is softer than the high-density portion DH. Furthermore, in this embodiment, the low-density portion DL has a thickness compared to the high-density portion DH. That is, as... Figure 7 As shown, the length H3 of the low-density portion DL in the thickness direction is longer than the length Hdh of the high-density portion DH in the thickness direction (Hdh < H3). Therefore, it is easy to use the low-density portion DL in the non-skin side layer 3, which is located around the high-density portion DH, to buffer the force applied to the sanitary napkin 1. As a result, concerns about the force applied to the sanitary napkin 1 being concentrated on the skin side of the sanitary napkin 1 are easily reduced, and wrinkles are less likely to occur.

[0147] The "linear" high-density section DH is not limited to sections that are continuously formed in a linear fashion with a density higher than the surrounding sections. When multiple high-density sections are intermittently arranged in a linear or dotted pattern, the area between adjacent high-density sections is also defined as a linear high-density section DH. The area between adjacent high-density sections that are close to each other is a region where the fiber density is lower than the fiber density of the section formed as a high-density section, but the fiber density is higher than the surrounding area; therefore, as a whole, it forms a linear high-density section.

[0148] For the high-density portion DH of the sanitary napkin 1 in this embodiment, a plurality of high-density portions DH are arranged at predetermined intervals along the width direction, continuing continuously in the length direction from the upper end to the lower end of the non-skin side layer 3. The continuous high-density portion DH in the length direction has a wavy shape with alternating concave and convex portions on both sides in the width direction. For example... Figure 7 As shown, in the sanitary napkin 1 of this embodiment, the length in the thickness direction of the low-density portion DL is the length H3 in the thickness direction of the non-skin side layer 3, and the length Hdh in the thickness direction of the high-density portion DH is shorter than the length H3 in the thickness direction of the low-density portion DL (Hdh < H3). The comparison of the thicknesses of the high-density portion DH and the low-density portion DL of the non-skin side layer 3 can be performed using known methods, for example, by the method described above.

[0149] The high-density section DH can be formed, for example, by clamping and conveying a nonwoven fabric sheet with approximately uniform thickness in the non-skin side layer 3 between a pair of rollers during the manufacturing process. One of the rollers is a heat-embossing roller with protrusions on its outer peripheral surface, and the other roller is an anvil roller with a smooth outer peripheral surface. By heating the fiber 3f to a temperature higher than the softening point but lower than the melting point of the potentially crimped fiber 3f in the non-skin side layer 3, the fiber 3f is prevented from fusing in the high-density section DH, making it easier to maintain a thickness in the high-density section DH that is thinner than that in the low-density section DL.

[0150] Furthermore, it is preferable that the non-skin side layer 3 has a recessed portion DH that is concave in the thickness direction on the skin side surface. In the sanitary napkin 1 of this embodiment, the high-density portion DH is the recessed portion DH. Since the portion DH of the non-skin side layer 3 can be used to provide a part that is separated from the skin side layer 2, concerns about excrement temporarily absorbed by the non-skin side layer 3 returning to the skin side layer 2 can be reduced. As a result, discomfort to the wearer's skin can be reduced. In addition, compared to the case where the skin side surface of the non-skin side layer 3 is flat, by having a recessed portion DH on the skin side surface of the non-skin side layer 3, the non-skin side layer 3 can easily deform by utilizing the stiffness difference between the recessed portion DH and the low-density portion DL when force is applied to the sanitary napkin 1. Therefore, it is easy to use the non-skin side layer 3 to buffer the force applied to the sanitary napkin 1, it is easy to reduce concerns about force concentration on the skin side layer 2 of the sanitary napkin 1, and it is easy to prevent wrinkles from forming on the skin side surface of the sanitary napkin 1.

[0151] Furthermore, in the non-skin side layer 3 of the sanitary napkin 1, the skin side has a recessed portion facing the non-skin side, and the non-skin side has a flat surface, but is not limited to this. Recesses may also be present on both the skin side and the non-skin side of the non-skin side layer 3. Additionally, when viewed along the thickness direction, the recesses on the skin side and the non-skin side may be located in the same position or in different positions. Furthermore, the recess DH of the non-skin side layer 3 of the sanitary napkin 1 may be a high-density portion DH, but is not limited to this. For example, the recess DH may also be a portion having the same fiber density as the low-density portion DL.

[0152] In sanitary napkin 1, the skin-side layer 2 and the non-skin-side layer 3 overlap each other in a contacting state. Furthermore, the skin-side layer 2 and the non-skin-side layer 3 can be fixed together using an adhesive such as a heat-melt adhesive, or no adhesive may be used. In particular, when viewing sanitary napkin 1 along its thickness direction, no adhesive is used between the skin-side layer 2 and the non-skin-side layer 3 in the central part of the width direction. This reduces concerns that the adhesive might hinder the absorption of excrement while worn. Furthermore, when an adhesive is used between the skin-side layer 2 and the non-skin-side layer 3, the fibers of the skin-side layer 2 and the non-skin-side layer 3 are fixed together by the adhesive, thereby restricting the movement and deformation of the fibers 2f of the skin-side layer 2 and the fibers 3f of the non-skin-side layer 3. Additionally, the stiffness of the portion fixed by the adhesive is easily increased. Therefore, when an adhesive is provided between the skin-side layer 2 and the non-skin-side layer 3, the force applied to the sanitary napkin 1 tends to concentrate on the portion of the skin-side layer 2 and the non-skin-side layer 3 that is fixed by the adhesive, and wrinkles are easily formed on the skin-side of the sanitary napkin 1 due to the locally concentrated force. In contrast, when no adhesive is provided between the skin-side layer 2 and the non-skin-side layer 3, since the fibers of the skin-side layer 2 and the non-skin-side layer 3 are not fixed by the adhesive, concerns about restricted movement and deformation of the fibers 2f of the skin-side layer 2 and the fibers 3f of the non-skin-side layer 3 can be reduced. This prevents the stiffness of the fibers 2f of the skin-side layer 2 and the fibers 3f of the non-skin-side layer 3 from increasing due to the use of adhesive for fixation. Thus, by not providing an adhesive between the skin-side layer 2 and the non-skin-side layer 3, concerns about wrinkles forming on the skin-side of the sanitary napkin 1 due to locally concentrated force on the fixed portion between the skin-side layer 2 and the non-skin-side layer 3 can be reduced.

[0153] In addition, such as Figure 5As shown, preferably, the thickness H2 of the skin-side layer 2 is thicker than the thickness H3 of the non-skin-side layer 3 (H2 > H3). Compared to the case where the thickness H2 of the skin-side layer 2 is thinner than the thickness H3 of the non-skin-side layer 3, the thicker thickness H2 of the skin-side layer 2 allows the non-skin-side layer 3 to be kept away from the wearer's skin during wear. Therefore, concerns about excrement temporarily absorbed by the non-skin-side layer 3 returning to the skin-side side of the skin-side layer 2 can be reduced. In addition, the thicker thickness of the skin-side layer 2 that contacts the wearer's skin improves the skin feel of the sanitary napkin 1 during wear. Furthermore, compared to the case where the thickness H2 of the skin-side layer 2 is thinner than the thickness H3 of the non-skin-side layer 3, the thicker thickness H2 of the skin-side layer 2 makes it less prone to bending, thus reducing the likelihood of wrinkles forming on the skin-side side of the sanitary napkin 1.

[0154] Regarding the second layer of the skin, such as Figure 5 As shown in Figure A, when the skin-side layer 2 is divided into three equal parts along its thickness direction, with the region closest to the skin side designated as the skin-side region Ru, the region closest to the non-skin side designated as the non-skin-side region Rd, and the area between the skin-side region Ru and the non-skin-side region Rd designated as the intermediate region Rm, the average narrowness of the non-skin-side region Rd in the narrowness evaluation test, used to quantitatively evaluate the narrowness of the voids formed by the fibers 2f, is narrower than the average narrowness of the skin-side region Ru in the narrowness evaluation test. Therefore, it is easier to utilize capillary action to introduce liquid into the non-skin-side region Rd compared to the skin-side region Ru.

[0155] Regarding the potentially shrinkable fibers in the skin-side layer 2 of the sanitary napkin 1, the fibers 2f themselves have the property of not absorbing liquid (excrement) as easily as liquid-absorbent fibers such as pulp fibers. Therefore, because the skin-side layer 2 has fibers 2f with potentially shrinkable fibers, even when excrement is absorbed while wearing the napkin, the fibers 2f themselves are not prone to thickening, and the gaps formed by the fibers 2f can be maintained. Furthermore, since the average narrowness of the non-skin-side region Rd in the narrowness evaluation test is narrower than the average narrowness of the skin-side region Ru in the narrowness evaluation test, it is easier to utilize capillary action to guide excrement received by the skin-side side of the skin-side region Ru towards the non-skin-side region Rd while wearing the napkin. In addition, it is easier for the excrement introduced into the non-skin-side region Rd to diffuse over a larger area within the non-skin-side region Rd. Therefore, concerns can be reduced that, while wearing the sanitary napkin, excrement absorbed from the skin-side area RU remains on the skin-side area RU and within the skin-side area RU, causing continuous contact between the excrement and the wearer's skin, resulting in discomfort and roughness. Furthermore, even when a large amount of excrement is expelled at once, it easily diffuses from the skin-side area RU towards the non-skin-side area Rd, thus reducing concerns about leakage from the sanitary napkin 1 due to excrement flowing along the surface of the skin-side area RU. Moreover, the average narrowness of the non-skin-side area Rd in the narrowness evaluation test is narrower than the average narrowness of the skin-side area RU in the narrowness evaluation test, facilitating the diffusion of excrement within the skin-side layer 2 from the skin-side to the non-skin-side, and from the skin-side layer 2 towards the non-skin-side layer 3. This reduces the amount of excrement remaining on the skin-side surface of the skin-side layer 2, improving comfort for the wearer.

[0156] Furthermore, in the skin side layer 2, compared to the case where the average narrowness of the non-skin side region Rd in the narrowness evaluation test is wider than the average narrowness of the skin side region Ru in the narrowness evaluation test, by making the average narrowness of the non-skin side region Rd in the narrowness evaluation test narrower than the average narrowness of the skin side region Ru in the narrowness evaluation test, the diffusion of excrement from the skin side region Ru to the non-skin side region Rd is promoted. This results in a smaller diffusion area of ​​excrement in the skin side region Ru and a larger diffusion area of ​​excrement in the non-skin side region Rd. Therefore, it is easier to promote the diffusion of excrement from the skin side layer 2 to the non-skin side layer 3, and it is easier to promote the diffusion of excrement in the non-skin side layer 3. Figure 8 As shown, the diffusion area B3 of excrement in the non-skin side layer 3 is larger than the diffusion area B2 of excrement in the skin side layer 2. Figure 8 This is a diagram illustrating a sanitary napkin 1 that has been soaked with horse blood for 30 minutes. Figure 8This diagram illustrates the state of sanitary napkin 1 after 30 minutes, following a 6mm drop of horse blood onto its central portion along both its length and width. In this way, the area of ​​the diffusion region B3 of the excrement in the non-skin side layer 3 is larger than the area of ​​the diffusion region B2 of the excrement in the skin side layer 2, thus easily giving the user the impression that sanitary napkin 1 has excellent absorbency.

[0157] Furthermore, generally speaking, the narrower the gaps formed by fibers 2f, the denser the fiber structure, the more difficult it is for fibers 2f to move, and the easier it is for the fiber shape to recover when force is applied to fibers 2f (skin side layer 2). Skin side layer 2 is a non-woven sheet formed by fibers 2f intertwining. Therefore, the denser the fiber structure, the more restricted the movement of the intertwined fibers 2f. When force is applied to skin side layer 2 from the outside, the degree of freedom of fibers 2f is easily reduced, making it difficult for the fiber shape to recover. In contrast, compared to the case where the average narrowness of skin side region Ru is smaller than the average narrowness of non-skin side region Rd, the average narrowness of skin side region Ru is larger than the average narrowness of non-skin side region Rd, making it less likely for the fiber structure of skin side region Ru to become denser, facilitating fiber movement, and thus improving the recovery of fiber 2f when force is applied. Therefore, by reducing concerns about wrinkles and creases forming on the skin-side area Ru compared to the non-skin-side area Rd, it is easier to reduce wrinkles and creases on the skin-side of the sanitary napkin 1.

[0158] As described above, in the sanitary napkin 1 of this embodiment, a nonwoven sheet of skin-side layer 2 is formed using a hydroentangling process. By pouring water from the skin side toward the non-skin side, the fibers 2f are easily pressed in from the skin side toward the non-skin side. In the narrowness evaluation test, the average narrowness of the non-skin side region Rd is narrower than the average narrowness of the skin side region Ru. Furthermore, the method for making the average narrowness of the non-skin side region Rd narrower than the average narrowness of the skin side region Ru in the narrowness evaluation test is not limited to this. For example, the thickness (fiber diameter) of the fibers 2f in the non-skin side region Rd may be made finer than the thickness (fiber diameter) of the fibers 2f in the skin side region Ru. Alternatively, by using a potentially shrinkable fiber with stronger shrinkage properties for the fibers 2f used in the non-skin side region Rd than for the fibers 2f used in the skin side region Ru, the average narrowness of the non-skin side region Rd in the narrowness evaluation test may be narrower than the average narrowness of the skin side region Ru in the narrowness evaluation test.

[0159] Preferably, the proportion of voids in the non-skin side region Rd in the void ratio evaluation test, used to quantitatively evaluate the proportion of voids in the measurement area Y, is smaller than the proportion of voids in the skin side region Ru in the void ratio evaluation test. The void ratio evaluation test can be performed using the method described later. Therefore, when the sanitary napkin 1 (skin side layer 2) absorbs excrement, it is easier to utilize capillary action to introduce excrement from the skin side region Ru to the non-skin side region Rd, where the void ratio is smaller, thus facilitating the diffusion of excrement from the skin side region Ru to the non-skin side region Rd. Furthermore, it is easier to promote the diffusion of excrement within the non-skin side region Rd. Therefore, when worn, it is easier to reduce the amount of excrement remaining in the skin side region Ru, thereby reducing discomfort caused by the contact between excrement and the wearer's skin. In addition, generally speaking, the smaller the void ratio of fiber 2f, the denser the fiber structure, the more difficult the fiber 2f is to move, and the easier it is for the fiber shape to recover when force is applied to fiber 2f (skin side layer 2). In contrast, compared to a situation where the porosity of the skin-side region Ru is smaller than that of the non-skin-side region Rd, a larger porosity of the skin-side region Ru makes it less likely for the fiber structure of the skin-side region Ru to become denser, facilitating fiber movement. This, in turn, improves the resilience of fiber 2f when force is applied. Consequently, by reducing concerns about wrinkles and creases forming on the skin-side side of the sanitary napkin 1 compared to the non-skin-side region Rd, wrinkles and creases on the skin-side of the sanitary napkin 1 are reduced.

[0160] In the sanitary napkin 1 of this embodiment, as described above, a nonwoven fabric sheet with a skin-side layer 2 is formed using a hydroentangling process. By pouring water from the skin side toward the non-skin side, the fibers 2f are pressed in from the skin side toward the non-skin side. Therefore, in the porosity evaluation test, the porosity ratio of the non-skin side region Rd is smaller than that of the skin side region Ru. Furthermore, the method for making the porosity ratio of the non-skin side region Rd smaller than that of the skin side region Ru in the porosity evaluation test is not limited to this. For example, the fiber diameter of the non-skin side region Rd may be made finer than that of the fiber diameter of the skin side region Ru. Alternatively, a potential shrinkage fiber with stronger shrinkage properties than the fiber diameter of the skin side region Ru may be used for the fiber 2f used in the non-skin side region Rd, thereby making the porosity ratio of the non-skin side region Rd smaller than that of the skin side region Ru in the porosity evaluation test.

[0161] <Test methods for evaluating narrowness and evaluation of void ratio>

[0162] The narrowness evaluation test and the void ratio evaluation test (described later) of the skin side layer 2 of the sanitary napkin 1 in this embodiment were conducted by Toray Research Center Co., Ltd.

[0163] Narrowness evaluation tests and void ratio evaluation tests can be conducted, for example, using the following methods.

[0164] First, X-ray CT measurements were performed on the lateral layer 2 of the skin. Non-destructive computed tomography (CT measurements) was performed using a Rigaku nano3DX high-resolution 3DX X-ray microscope under the following conditions.

[0165] X-ray source: Cu

[0166] Tube voltage - tube current: 40kV-30mA

[0167] Detector: sCMOS camera (lens: 1080)

[0168] Resolution: 2.51μm / voxel

[0169] The measurement area (predetermined area) Y of the skin side layer 2 is randomly extracted from the 3D data obtained by photography, and the voids are analyzed. In addition, the measurement area Y used for this analysis is a cuboid (or cube) located in any range in the face direction of the skin side layer 2 and whose length in the thickness direction is the thickness H2 of the skin side layer 2.

[0170] In this embodiment, such as Figure 9 As shown, when the measurement area Y is divided into three equal parts along the thickness direction, the bottom side is designated as the first area Y1, the top side is designated as the third area Y3, and the area between the first area Y1 and the third area Y3 is designated as the second area Y2. Figure 9 This diagram illustrates the measurement area Y. Fiber 2f represents the colored (gray) portion, the gaps represent the colored (white) portion, and the grid represents the range of the measurement area randomly sampled from the skin side layer 2. Region 1 Y1 is a portion of the skin side region Ru of skin side layer 2 (viewed along the thickness direction). Region 2 Y2 is a portion of the middle region Rm of skin side layer 2 (viewed along the thickness direction). Region 3 Y3 is a portion of the non-skin side region Rd of skin side layer 2 (viewed along the thickness direction).

[0171] The tomographic images obtained using X-ray CT are such that the low-density (void) components that are easily transmitted by X-rays are represented in black, while the high-density (fibrous) components that easily absorb X-rays are represented in white. Based on this image, the proportion of voids and the average narrowness of the voids in each region Y1 to Y3 are calculated.

[0172] The void ratios of each region Y1 to Y3 can be calculated by obtaining the void volume in each region Y1 to Y3 and the volume of the measurement region Y from the tomographic images obtained using X-ray CT. For example, the void ratio of region Y1 is as follows.

[0173] The void ratio of region Y1 = (volume of voids in region Y1) / (volume of region Y1)

[0174] Furthermore, the volume of region Y1 is the sum of the volume of the fibers in region Y1 and the volume of the voids in region Y1.

[0175] Regarding the narrowness of the gaps in each region Y1–Y3, the concept of "Thickness" from "A new method for the mode-independent assessment of thickness in three-dimensional images" (T. HILDEBRAND & P. ​​RUEGSEGGER, Journal of Microscopy, Vol. 185, Pt1, January 1997, pp. 67-75) is applied to the spatial portion, and the distribution of gap narrowness and the average narrowness of the gaps are calculated based on the narrowness of a portion of the volume (gap). In other words, the "Thickness" defined in the aforementioned literature corresponds to the "narrowness of the gaps" in the skin lateral layer 2 (regions Y1–Y3), specifying the narrowness in each portion of the volumetric portion of the gap in the tomographic image obtained using X-ray CT. This allows for the acquisition of the distribution of gap narrowness and the average narrowness of the gaps.

[0176] A summary of the quantitative evaluation method for the narrowness of the voids (e.g., void Z) within each analyzed region Y1 to Y3 is provided. Figure 10 This diagram illustrates a general overview of the evaluation method for the narrowness of gap Z. For example, as... Figure 10 As shown, for any points P1 to P4 inside the gap Z, assuming the largest sphere within the region containing each point, the diameters D1 to D4 of each sphere are calculated. Furthermore, using... Figure 10 The process of determining the diameters D1 to D4 of the spheres at four points (P1 to P4) has been explained. However, for the quantitative evaluation of the actual narrowness of the gap, the following process is used: the diameter D of the spheres at multiple points P inside the gap Z is determined. This process is performed on all points within each region Y1 to Y3, the distribution of the obtained diameters is calculated, and the average value is obtained. This allows for a quantitative evaluation of the average narrowness of the gap in each region Y1 to Y3.

[0177] Figure 11 This is a graph showing the results of the narrowness evaluation test and the void ratio evaluation test. Figure 11 The figure shows the average void width (μm), minimum void width (μm), maximum void width (μm), standard deviation, and porosity (%) of each region of measurement region Y, region 1 Y1, region 2 Y2, and region 3 Y3 obtained through the above measurements. In this embodiment, the average void width of region 1 Y1 of measurement region Y is 117 μm, and the average void width of region 3 Y3 is 91 μm. Therefore, it is clear that the average void width of region 3 Y3 is narrower than that of region 1 Y1. According to this result, it can be seen that in the skin side layer 2, the average void width of the non-skin side region Rd in the void width evaluation test is narrower than the average void width of the skin side region Ru in the void width evaluation test.

[0178] Regarding the skin side layer 2, preferably, when at least a portion of the fibers 2f in the non-skin side region Rd has a higher hydrophilicity than the fibers 2f in the skin side region Ru, a portion of the fibers 2f in the non-skin side region Rd is exposed on the skin-side surface of the skin side layer 2. Specifically, preferably, as... Figure 5 As shown in Figure A, the skin-side layer 2 has hydrophilic fibers 2fb in the non-skin-side region that have a higher hydrophilicity than the fibers 2f in the skin-side region Ru, and also has hydrophilic fibers 2fb on the skin-side surface exposed to the skin side of the skin-side layer 2. The hydrophilicity of each region is determined based on the contact angle with water. The measurement of the contact angle with water in each region will be described later. The hydrophilic fibers 2fb on the skin-side surface exposed to the skin side of the skin-side layer 2 easily introduce excrement absorbed from the skin-side towards the non-skin-side region Rd. Therefore, in the skin-side layer 2, it is easy to promote the diffusion of excrement from the skin side to the non-skin side, and it is easy to promote the diffusion of liquid in the non-skin-side region Rd. This reduces concerns about excrement residue on the skin-side surface of the skin-side region Ru, and reduces discomfort caused by continuous contact between excrement and the wearer's skin, thereby improving wearing comfort.

[0179] For the skin-side layer 2 of this embodiment, during the formation of the nonwoven fabric sheet, high-pressure water jet treatment, such as water jetting, is performed while the hydrophobic fibers 2fa in the skin-side region Ru and the hydrophilic fibers 2fb in the non-skin-side region Rd are stacked, thereby interweaving the fibers between each fiber layer and the fibers of each mesh (step (d) of forming nonwoven fabric based on the above-described hydroentangling method). At this time, the water flow passing through in the order of hydrophobic fibers 2fa and hydrophilic fibers 2fb is reflected by the conveyor belt and directed towards the skin side in the order of hydrophilic fibers 2fb and hydrophobic fibers 2fa, thereby pulling the hydrophilic fibers 2fb towards the skin-side region Ru. Thus, the hydrophilic fibers 2fb are provided on the skin-side surface exposed to the skin side of the skin-side layer 2.

[0180] Furthermore, the method for setting the hydrophilic fibers 2fb on the skin-side surface exposed to the skin side layer 2 is not limited to this. Known methods can be used. For example, after interlacing the fibers 2f using hydroentangling, the hydrophilic fibers 2fb can be exposed on the skin-side surface of the skin side layer 2 using acupuncture.

[0181] Furthermore, preferably, the hydrophilicity of the skin side layer 2 is lower than that of the non-skin side layer 3. For example... Figure 5 As shown in Figure A, the skin-side layer 2 of this embodiment comprises an upper layer 2A mostly formed of hydrophobic fibers 2fa and a lower layer 2B mostly formed of hydrophilic fibers 2fb. The hydrophilicity of fiber 2fb is higher than that of fiber 2fa. Hydrophobic fibers 2fa are provided on the skin side, and hydrophilic fibers 2fb are provided on the non-skin side. The non-skin-side layer 3 is formed of hydrophilic fibers 3f. Figure 5 (B) Furthermore, the skin-side layer 2 is more hydrophobic, while the non-skin-side layer 3 is more hydrophilic than the skin-side layer 2. Therefore, when worn, it reduces the amount of excrement absorbed by the skin-side layer 2 remaining on it, and facilitates its introduction towards the non-skin-side layer 3. Additionally, it facilitates the diffusion of excrement that reaches the non-skin-side layer 3 within it, reducing concerns about excrement returning from the non-skin-side layer 3 to the skin-side layer 2. Thus, it reduces concerns about continuous contact between excrement and the wearer's skin.

[0182] The hydrophilicity of each layer is determined based on its contact angle with water. The contact angle of each layer with water can be measured using the following methods.

[0183] First, a quadrilateral shape, 150 mm in length and 70 mm in width, is cut from the area (layer) of the object to be measured, to serve as the measurement sample (if it is difficult to cut, the maximum length and width are not limited to the illustrated values ​​as long as they are within the measurable range). Then, a droplet of ion-exchanged water is attached to the surface of the sample to be measured, and the image of the droplet is recorded. The contact angle is measured based on the recorded image. More specifically, a VHX-1000 microscope manufactured by Keyence Corporation is used as the measuring device, and a medium-magnification zoom lens is mounted on the device at a 90° inverted position. Each measurement sample is placed on the measuring stage of the measuring device with the surface to be measured facing upwards, allowing observation from the width direction of each sample. Then, a droplet of 3 μL of ion-exchanged water is attached to the surface of the sample placed on the measuring stage, and the image of the droplet is recorded and input into the measuring device. Of the recorded images, 10 images with both ends or one end of the droplet clearly visible in the width direction were selected. The contact angle of the droplet was measured for each of these 10 images, and the average of these contact angles was taken as the contact angle of the measurement area (fiber layer). The measurement environment was set to 20℃ / 50%RH.

[0184] The smaller the contact angle with water measured using the above method, the higher the hydrophilicity (the lower the hydrophobicity); the larger the contact angle, the lower the hydrophilicity (the higher the hydrophobicity). If the contact angle is less than 90 degrees, it is hydrophilic; if the contact angle is greater than 90 degrees, it is hydrophobic. In other words, the contact angle between the skin side layer 2 and water is larger than that between the non-skin side layer 3 and water.

[0185] In this embodiment, the skin-side layer 2 has fibers 2fa, which are hydrophobic fibers, on the skin side in the thickness direction, and fibers 2fb, which are hydrophilic fibers, on the non-skin side in the thickness direction. On the other hand, the non-skin side layer 3 has fibers 3f, which are hydrophilic fibers. Thus, the hydrophilicity of the skin-side layer 2 is lower than that of the non-skin side layer 3, but this is not a limitation. For example, the entire area of ​​each nonwoven fabric sheet of the skin-side layer 2 and the non-skin side layer 3 can be formed of fibers 2f and 3f with constant hydrophilicity, and a process of coating the skin-side layer 2 with a hydrophobic agent can be performed, as can a process of coating the non-skin side layer 3 with a hydrophilic agent.

[0186] Furthermore, the sanitary napkin 1 possesses the desired absorbency. The absorbency of the sanitary napkin 1 can be measured using the following absorbency test.

[0187] <Methods for measuring absorption function>

[0188] (1) First, prepare 1 sanitary napkin.

[0189] (2) Next, observe the sanitary napkin 1 along the thickness direction, and designate the central portion in both the length and width directions as a predetermined area, and cut out this predetermined area as a sample. In the sanitary napkin 1 of this embodiment, the sample is 70mm × 70mm in size.

[0190] (3) Then, the weight a before absorption, which is the weight of the sample, is measured using a balance with a sensitivity of 0.01g. The weight a before absorption is the weight of the sample before absorbing distilled water.

[0191] (4) Next, use a clamp to hold one end of the sample and set the front end of the clamp and the sample to be perpendicular in the longitudinal direction.

[0192] Immerse the sample and fixture together in a water bath containing distilled water (or deionized water) at 23±1℃. At this time, the skin side of the absorbent layer 10 should be facing upwards. Gently press the sample towards the water, keeping it completely immersed in the distilled water for 60 seconds.

[0193] (5) Then, pull up the clamp to lift the sample from the distilled water, and hold the sample with the clamp while it is completely out of the water surface of the tank, and suspend the sample from the clamp for 90 seconds.

[0194] (6) After that, weigh the mass of the sample excluding the fixture to obtain the weight after absorption, A, which is the weight of the sample after absorption.

[0195] (7) Then, the weight a before absorption is subtracted from the weight A after absorption to obtain the weight b after absorption.

[0196] (Absorbed weight b) = (Weight after absorption A) - (Weight before absorption a)

[0197] Preferably, the value obtained by dividing the absorbed weight b by the weight a before absorption is 5 or more.

[0198] Absorbed weight b ÷ unabsorbed weight a ≥ 5

[0199] Perform steps (1) to (7) above on 5 samples respectively, and take the average of the results of the 5 samples as the measurement result.

[0200] The larger the value obtained by dividing the absorbed weight b by the initial weight a, the more distilled water the sanitary napkin 1 can absorb, and therefore the more waste it can absorb. Compared to a value less than 5, setting the value of 5 or more ensures that the sanitary napkin 1 can adequately absorb liquid. In other words, it reduces concerns about wrinkles or creases on the sides of the skin and keeps absorbed liquid within the sanitary napkin 1. Thus, the sanitary napkin 1 is less prone to wrinkles or creases on the sides of the skin and has sufficient absorption capacity, allowing the absorbed waste to spread and be retained within the sanitary napkin 1.

[0201] Preferably, the bending stiffness B of the absorbent layer 10 in the sanitary napkin 1, which overlaps the skin-side layer 2 and the non-skin-side layer 3, at its central portion in both the length and width directions, is 1.2 gf·cm based on the KES method. 2 / cm or less. In this embodiment, the central portion of the absorbent layer 10 in the length direction is the crotch area, and the central portion in both the length and width directions is also the area where the excretion opening abuts when worn. Generally speaking, the larger the value of the bending stiffness B, the stronger the bending resistance. The bending stiffness B of the central portion in both the length and width directions of the absorbent layer 10 is 1.2gf·cm. 2 Compared to cases with a large / cm, the bending stiffness B based on the KES method is set to 1.2gf·cm at the central part of the absorption layer 10 in both the length and width directions. 2 The absorbent layer 10 is softened to a depth of less than 6 cm, making it easier to soften the sanitary napkin 1 that uses the absorbent layer 10. Therefore, even when force is applied to the sanitary napkin 1, wrinkles are less likely to form on the skin side of the sanitary napkin 1. In addition, when worn, the sanitary napkin 1 easily follows the shape and movement of the wearer's body, reducing discomfort to the wearer and improving comfort when worn.

[0202] <Method for measuring bending stiffness B>

[0203] The bending stiffness B (gf·cm) of the central portion in the length direction and the central portion in the width direction of the absorbing layer 10 2 B(gf·cm) can be measured using well-known methods. For example, bending stiffness B (gf·cm) 2The value ( / cm) can be measured using the KES-FB2-L large-scale bending tester manufactured by Kado Technology Co., Ltd. First, the absorbent layer 10 is removed from the sanitary napkin 1 (with the skin-side layer 2 and non-skin-side layer 3 overlapping), and a 50mm x 50mm portion of the central part of the absorbent layer 10 in both the length and width directions is cut out as a sample. This sample is then fixed between the chucks of the tester in a way that allows measurement by bending it along the length of the absorbent layer 10. The bending is performed towards the front side to the maximum curvature +0.5cm. -1 Next, bend towards the back side to the maximum curvature of -0.5cm. -1 The structure is then restored, and measurements are taken based on this restoration. Bending stiffness B (gf·cm) 2 The value ( / cm) is calculated based on the average of the slope of the bending moment relative to curvatures of 0.1 to 0.3 when bending towards the front side and the slope relative to curvatures of -0.1 to -0.3 when bending towards the back side.

[0204] Figure 12 Figure A shows the measurement results of bending characteristics based on the KES method. Figure 12 A shows the measurement results of the bending characteristics of the absorbent layer 10 of the sanitary napkin 1 of this embodiment and the absorbent body (absorbent layer) of a comparative product X, which is a conventional sanitary napkin for menstrual use, based on the KES method.

[0205] Comparative Product X has a well-known structure, consisting of a surface sheet, absorbent core, and backing sheet, arranged sequentially from the skin side. The surface sheet of Comparative Product X is a sheet material that exhibits excellent liquid permeability while effectively absorbing or retaining liquid. The absorbent core of Comparative Product X is a polymer foam structure capable of absorbing and retaining liquid. The backing sheet of Comparative Product X is a liquid-impermeable sheet material. Since the surface sheet of Comparative Product X allows liquid to pass through but does not effectively absorb or retain liquid, it is determined that the absorbent layer of Comparative Product X consists only of the absorbent core. The absorbent core was removed from Comparative Product X, and its bending characteristics were measured at the center of both the length and width directions, similar to those of Sanitary Napkin 1, using the aforementioned KES method.

[0206] like Figure 12 As shown in Figure A, the bending stiffness B (gf·cm) of the absorbent layer 10 of the sanitary napkin 1 in this embodiment is the central portion in both the length and width directions. 2 / cm) is 0.1008gf·cm 2 / cm~1.1017gf·cm 2 / cm, which is 1.2gf·cm 2 / cm or less. In contrast, compare the bending stiffness B (gf·cm) of the central portion of the absorber in the length direction and the central portion in the width direction of product X. 2 / cm) is 0.5493gf·cm 2 / cm~6.1168gf·cm 2 / cm. Additionally, the average value of the measured bending stiffness B of the absorbent layer 10 of the sanitary napkin 1 (0.5390 gf·cm) 2 The bending stiffness B of the absorber of comparison product X (2.5294 gf·cm) is less than the average value of the measured results (2.5294 gf·cm). 2 According to the results, the absorbent layer 10 of sanitary napkin 1 is softer than the absorbent body of comparative product X, thus making sanitary napkin 1 softer than comparative product X, and therefore sanitary napkin 1 is less prone to wrinkling compared to comparative product X. Furthermore, compared to comparative product X, sanitary napkin 1 more easily follows the shape and movement of the wearer's body when worn, reducing discomfort and improving comfort during wear.

[0207] Preferably, the bending hysteresis 2HB of the absorbent layer 10 in the sanitary napkin 1, at the center of its length direction and at the center of its width direction, is 0.93 gf·cm. 2 / cm or less. The 2HB value represents bending recoverability; the larger the bending hysteresis 2HB value, the worse the recoverability. The bending hysteresis 2HB based on the KES method at the central portion of the absorber layer 10 in both the length and width directions is greater than 0.93 gf·cm. 2 Compared to the case of / cm, the bending hysteresis 2HB based on the KES method is set to 0.93gf·cm at the central part of the absorption layer 10 in both the length and width directions. 2 The absorbent layer 10 is shaped to a minimum of 0.5 cm, making it easier for it to return to its original shape after being deformed by external forces while worn. Therefore, even when force is applied to the sanitary napkin 1, concerns about wrinkles forming on the skin-friendly side of the napkin 1 are reduced. Furthermore, discomfort and unease caused to the wearer due to deformation of the absorbent layer 10 are reduced.

[0208] <Method for measuring bending hysteresis 2HB>

[0209] The bending hysteresis 2HB (bending resilience) can be measured using known methods. For example, it can be measured using an automated bending testing machine (KES-FB2-L) manufactured by Kado Technology Co., Ltd.

[0210] First, take out the absorbent layer 10 from the sanitary napkin 1 (with the skin side layer 2 and non-skin side layer 3 overlapping), and cut out a 50mm × 50mm portion of the absorbent layer 10 at the center of its length and width as a sample.

[0211] Next, use a chuck to hold the sample at both ends along its length. Then, move the sample at a rate of curvature change of 0.1 cm. -1 / min becomes 0.5cm on the positive side of the curvature. -1 And it becomes 0.5cm to the negative side. -1 Within a certain range, bending in both positive and negative directions yields hysteresis curves representing the bending moment required for bending in each direction. The curvature is 0.1 cm. -1 The hysteresis of the bending moment is set as the bending hysteresis 2HB.

[0212] Similar to bending stiffness B, in Figure 12 Figure A shows the bending hysteresis 2HB (gf·cm) of the absorbent layer 10 of the sanitary napkin 1 in this embodiment, which is the central part in the length direction and the central part in the width direction, based on the KES method. 2 The measurement results ( / cm) and the bending hysteresis 2HB (gf·cm) of the absorber of product X at the center of the length direction and the center of the width direction based on the KES method were compared. 2 The measurement results ( / cm).

[0213] like Figure 12 As shown in Figure A, the bending hysteresis 2HB (gf·cm) of the absorbent layer 10 of the sanitary napkin 1 in this embodiment is located at the center of the absorbent layer 10 in both the length and width directions. 2 / cm) is 0.8204gf·cm 2 / cm~0.9253gf·cm 2 / cm, therefore it is 0.93gf·cm 2 / cm or less. In contrast, the bending hysteresis 2HB (gf·cm) at the central part of the absorber in the length direction and the central part in the width direction of product X is compared. 2 / cm) is 4.0183gf·cm 2 / cm~4.8341gf·cm 2 / cm, significantly higher than 0.93gf·cm 2 / cm. Based on this result, for sanitary napkin 1, compared to the comparative product, even when the absorbent layer 10 is deformed due to external forces such as the wearer's body shape and movement while worn, it is easier for the absorbent layer 10 to return to its original shape. Even when force is applied to the sanitary napkin 1, it is less prone to wrinkling compared to the comparative product X. Furthermore, compared to the comparative product X, it reduces discomfort and unpleasantness caused to the wearer due to deformation of the absorbent layer 10.

[0214] Preferably, the linearity LC (compression stiffness) of the compression characteristics based on the KES method at the central portion of the absorbent layer 10 in the sanitary napkin 1, both in the length and width directions, is 0.6 or higher. A higher linearity LC (compression stiffness) value indicates stronger compression resistance. Compared to a linearity LC (compression stiffness) less than 0.6, setting the linearity LC (compression stiffness) to 0.6 or higher reduces deformation of the absorbent layer 10. Therefore, even when force is applied to the sanitary napkin 1, concerns about wrinkles forming on the skin-friendly side of the sanitary napkin 1 are reduced. Furthermore, discomfort caused by deformation of the absorbent layer 10 during wear is reduced. Additionally, concerns about leakage of excrement from the absorbent layer 10 due to deformation are also reduced.

[0215] Furthermore, it is preferable that the compression resilience (RC) of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction of the sanitary napkin 1 is 38.0% or more based on the KES method. The closer the compression resilience (RC) value is to 100%, the higher the resilience. Even when the absorbent layer 10 is deformed due to force applied to the sanitary napkin 1 while wearing it, compared to a case where the compression resilience (RC) of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction is less than 38.0%, by setting the compression resilience (RC) of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction to 38.0% or more, the shape of the absorbent layer 10 is easily restored. Therefore, even when force is applied to the sanitary napkin 1, concerns about wrinkles forming on the skin side of the sanitary napkin 1 can be reduced. In addition, discomfort caused to the wearer by deformation of the absorbent layer 10 while wearing it can be reduced.

[0216] Furthermore, preferably, the compression work WC of the absorbent layer 10 in the sanitary napkin 1, located at the center of its length and width, is 1.3 gf·cm / cm. 2The higher the value of the compression work WC, the easier it is to compress. Therefore, a compression work WC less than 1.3 gf·cm / cm² is considered favorable. 2 In contrast, by setting the compression work WC of the central portion of the absorption layer 10 in both the length and width directions to 1.3 gf·cm / cm, the KES-based method is used. 2 Therefore, the absorbent layer 10 is easily compressed and less prone to wrinkling. Furthermore, the compression work WC is less than 1.3 gf·cm / cm. 2 Compared to other cases, the absorbent layer 10 has better shape recovery, thus reducing concerns about wrinkles forming on the skin-friendly side of the sanitary napkin 1. Furthermore, it reduces discomfort caused by deformation of the absorbent layer 10 during wear.

[0217] <Measuring methods for linearity (LC), compression resilience (RC), and compression work (WC) of compression properties>

[0218] The linearity of compression properties, LC (compression stiffness) and RC (compression resilience), can be measured using known methods. For example, they can be measured using the KES-FB3 AUTO-A automated compression testing machine manufactured by Kado Technology Co., Ltd.

[0219] First, take out the absorbent layer 10 from the sanitary napkin 1 (with the skin side layer 2 and non-skin side layer 3 overlapping), and cut out a 50mm × 50mm portion of the absorbent layer 10 at the center of its length and width as a sample.

[0220] For the predetermined area with a diameter of 200mm 2 Each sample was compressed between steel plates of circular planar terminals with a compression rate of 50 sec / mm and a maximum compression load of 50 gf / cm. 2 The compressibility characteristics of the sample were measured.

[0221] For the recovery process, the compression characteristics are also measured at the same rate, and the linearity LC and compression recovery rate RC [%) and compression work WC [gf·cm / cm] of the compression characteristics obtained from the measurements are determined. 2 ].

[0222] Figure 12 B is a graph representing the measurement results of the compression characteristics based on the KES method. Figure 12 B shows the measurement results of the compression characteristics of the absorbent layer 10 of the sanitary napkin 1 of this embodiment and the absorbent body (absorbent layer) of a comparative product X, which is a conventional menstrual sanitary napkin, based on the KES method. Furthermore, the comparative product X is the same as the product for which the bending characteristics were measured based on the KES method described above.

[0223] like Figure 12 As shown in B, the linearity LC of the compression characteristics of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction of the sanitary napkin 1 of this embodiment is 0.609 to 0.653, which is 0.6 or higher. In contrast, the linearity LC of the compression characteristics of the central portion of the absorbent body in the length direction and the central portion in the width direction of the comparative product X is 0.365 to 0.757. Furthermore, the average value of the linearity LC of the compression characteristics of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction of the sanitary napkin 1 of this embodiment is 0.632, while the linearity LC of the compression characteristics of the central portion of the absorbent body in the length direction and the central portion in the width direction of the comparative product X is 0.575. According to these results, the deformation of the absorbent layer 10 of the sanitary napkin 1 can be reduced compared to the absorbent body of the comparative product X. Therefore, compared to the comparative product X, even when force is applied to the sanitary napkin 1, concerns about wrinkles forming on the skin side of the sanitary napkin 1 can be reduced. In addition, it can reduce the discomfort caused to the wearer by the deformation of the absorbent layer 10 while wearing the sanitary napkin 1. Compared with the absorbent body of the comparative product X, it can reduce the leakage of excrement caused by the deformation of the absorbent layer 10.

[0224] For compression-resilience RC, also as Figure 12 As shown in Figure B, the compression resilience RC of the central portion of the absorbent layer 10 in the length direction and the central portion in the width direction of the sanitary napkin 1 of this embodiment is 38.80% to 40.18%, which is significantly greater than 38%. In contrast, the compression resilience RC of the central portion of the absorbent body in the length direction and the central portion in the width direction of the comparative product X is 41.50% to 59.45%. In other words, the absorbent layer 10 of the sanitary napkin 1 of this embodiment has the same compression resilience RC as the comparative product X, making it easier for the absorbent layer 10 to recover its shape and reducing concerns about wrinkles forming on the skin side of the sanitary napkin 1. In addition, it can reduce discomfort caused by deformation of the absorbent layer 10 during wear and improve breathability, thus improving comfort during wear.

[0225] For compression work WC, also as Figure 12 As shown in Figure B, the compression work WC of the absorbent layer 10 of the sanitary napkin 1 in this embodiment, at the center of both the length and width directions, is 1.365 gf·cm / cm. 2 ~1.646 gf·cm / cm 2 , is 1.3 gf·cm / cm 2 That's all. In contrast, the compressive work WC of the central portion of the absorber in the length direction and the central portion in the width direction of product X is 0.673 gf·cm / cm. 2 ~1.287 gf·cm / cm2 Less than 1.3 gf·cm / cm 2 Based on the compression work WC value, the absorbent layer 10 of sanitary napkin 1 is more easily compressed than that of comparative product X, exhibiting better resilience. Therefore, compared to the wrinkles formed on the skin-side of comparative product X, wrinkles are less likely to form on the skin-side of sanitary napkin 1. Furthermore, sanitary napkin 1 is less likely to cause discomfort due to deformation of the absorbent layer 10 (absorbent core) compared to comparative product X.

[0226] Furthermore, preferably, in the elongation test, which measures the force used to stretch the absorbent layer 10 (in a state where the skin-side layer 2 and the non-skin-side layer 3 overlap) by a predetermined length, the value obtained by dividing the force measured in the 10th elongation test of the absorbent layer 10 by the force measured in the 1st elongation test of the absorbent layer 10 is 50% or more. Because the value obtained by dividing the force measured in the 10th elongation test by the force measured in the 1st elongation test by the force measured in the 1st elongation test by 50% or more reduces damage to the absorbent layer 10 even when worn, and compared to cases where the value obtained by dividing the force measured in the 10th elongation test by the force measured in the 1st elongation test by less than 50%, the predetermined stress can be maintained even when the absorbent layer 10 is repeatedly stretched by applying force. Therefore, the sanitary napkin 1 with the absorbent layer 10 can easily follow the shape and movement of the wearer's body. In other words, a sanitary napkin 1 with such an absorbent layer 10 can be formed such that, when force is applied to the absorbent layer 10 from the outside while it is being worn, the absorbent layer 10 is not easily damaged, and the absorbent layer 10 easily adapts to the shape and movement of the wearer's body.

[0227] <Measuring Methods for Elongation Test>

[0228] Elongation tests can be performed using a cyclic test on an AUTOGRAPH type tensile testing machine manufactured by Shimadzu Corporation, such as the AG-1KNI model. The specific measurement method is as follows.

[0229] First, the absorbent layer 10 (with the skin-side layer 2 and non-skin-side layer 3 overlapping) of the sanitary napkin 1 (designated as the target area) is removed to prepare the sample. The absorbent layer 10 is fixed to the chuck of the testing machine with a chuck spacing of 100 mm for the cut sample. Next, the sample is stretched in the length direction at a speed of 100 mm / min to 130% of the chuck spacing of 100 mm, i.e., 130 mm, and then returned to the chuck spacing of 100 mm at a speed of 100 mm / min. The maximum value of the force (N) at this point is set as the measurement result value of the first elongation test (the value of the force measured in the first measurement).

[0230] Next, the material, initially with a chuck spacing of 100 mm, is stretched along its length at a speed of 100 mm / min to 130% of the 100 mm spacing, i.e., 130 mm, and then returned to the 100 mm spacing position at a speed of 100 mm / min. The maximum force (N) at this point is set as the measurement result of the second elongation test (the force value measured in the second test). Elongation tests are performed similarly to obtain the measurement results for the 3rd to 10th tests.

[0231] Then, the value obtained by dividing the 10th measurement result (the magnitude of the force measured in the 10th measurement) by the 1st measurement result (the magnitude of the force measured in the 1st measurement) is calculated.

[0232] Figure 13 This is a graph showing the measurement results of the elongation test of the absorber layer 10. Figure 13 The results of the elongation test of the absorbent layer 10 of the sanitary napkin 1 of this embodiment and the absorbent body (absorbent layer) of a comparative product X, which is a conventional menstrual sanitary napkin, are shown. Furthermore, the comparative product X is the same as the product for which the bending characteristics were measured using the KES method described above.

[0233] The measurement results (magnitude of force) of the elongation test of the absorbent layer 10 of sanitary napkin 1 are as follows: Figure 13 As shown, the measurement result (force magnitude) of the first elongation test of the absorbent layer 10 of sanitary napkin 1 is 20.967 N. The measurement result (force magnitude) of the tenth elongation test of the absorbent layer 10 of sanitary napkin 1 is 15.270 N. The value of the force magnitude measured in the tenth elongation test (15.270 [N]) divided by the value of the force magnitude measured in the first elongation test (20.967 [N]) yields a value of 15.270 [N] / 20.967 [N] = 0.7283, which is significantly higher than 50%. In contrast, in comparative product X, the absorbent core broke in the second elongation test, making it impossible to obtain the measurement result for the tenth elongation test. That is, the result is 0 N. For the absorbent layer 10 of the sanitary napkin 1, the value is also greater than 0N in the 10th measurement. Therefore, even when an external force is applied while wearing the napkin, damage or breakage of the absorbent layer 10 can be reduced. Thus, compared to the absorbent body of the comparative product X, the absorbent layer 10 of the sanitary napkin 1 of this embodiment is less prone to damage or breakage while wearing. Furthermore, compared to cases where the value obtained by dividing the force of the 10th elongation test by the force of the 1st elongation test is less than 50%, the absorbent layer 10 easily adapts to the wearer's body and movement, providing a comfortable wearing experience.

[0234] Furthermore, it is preferable that the air permeability resistance of the absorbent layer 10 (in the state where the skin-side layer 2 and the non-skin-side layer 3 overlap) is 0.32 kPa·s / m or less. Compared to cases where the air permeability resistance is greater than 0.32 kPa·s / m, by setting the air permeability resistance of the absorbent layer 10 to 0.32 kPa·s / m or less, the breathability of the sanitary napkin 1 can be improved. This reduces discomfort such as stuffiness caused by the sanitary napkin 1 to the wearer.

[0235] The air permeability resistance value of the absorbent layer 10 can be measured using known methods. For example, the absorbent layer 10 is cut out to a predetermined size (e.g., a circle with a diameter of 70 mm × 70 mm) and used as a sample. Then, using a KES-F8 air permeability testing machine manufactured by Gato Technology Co., Ltd. or an equivalent air permeability testing machine, the standard air permeability speed is set to 2 cm / s, and the air permeability resistance value of the sample is measured. This measurement is performed multiple times (e.g., 5 times), and the average value can be taken as the air permeability resistance value of the absorbent layer 10.

[0236] In the above embodiment, the fibers (potentially coiled fibers) 2f constituting the skin side layer 2 and the fibers (potentially coiled fibers) 3f constituting the non-skin side layer 3 are set to have the same thickness (2.2 dtex), but are not limited thereto. The thickness (fiber diameter) of the fibers 2f in the skin side layer 2 and the thickness (fiber diameter) of the fibers 3f in the non-skin side layer 3 can be selected arbitrarily. For example, the maximum value of the thickness of the fibers in the skin side layer 2 can also be greater than the maximum value of the thickness of the fibers in the non-skin side layer 3. In general nonwoven fabrics, the thicker the fibers, the easier it is for the gaps formed by the multiple fibers to become larger. Therefore, by making the maximum value of the thickness of the fibers in the skin side layer 2 greater than the maximum value of the thickness of the fibers in the non-skin side layer 3, it is easier to introduce excretions into the non-skin side layer 3 by utilizing capillary phenomena compared to the skin side layer 2, and it is easier for the excretions to diffuse within the non-skin side layer 3. Therefore, while wearing the garment, concerns about continuous contact between excrement and the wearer's skin are reduced, thus improving comfort. Furthermore, generally speaking, the finer the fiber 2f, the denser the fiber structure, the less likely the fiber 2f is to move, and the easier it is for the fiber 2f (skin-side layer 2) to regain its shape when force is applied. Conversely, compared to a situation where the fiber 2f in the skin-side region Ru is thinner than the fiber 2f in the non-skin-side region Rd, the fiber 2f in the skin-side region Ru is thicker than the fiber 2f in the non-skin-side region Rd, making it less likely for the fiber structure of the skin-side region Ru to become dense, facilitating fiber movement, and thus improving the fiber 2f's resilience when force is applied. This reduces concerns about wrinkles and creases forming in the skin-side region Ru compared to the non-skin-side region Rd, thus reducing wrinkles and creases on the skin-side of the sanitary napkin 1.

[0237] In the above embodiment, the absorbent layer 10 is formed by overlapping the skin-side layer 2 (which is a non-woven fabric sheet) and the non-skin-side layer 3 (which is a non-woven fabric sheet) in a state of mutual contact, but it is not limited to this. Figure 14 This diagram illustrates a modified example of the sanitary napkin 100 according to this embodiment. It can also be as follows: Figure 14 The sanitary napkin 100 shown has a structure in which the skin-side layer 2 and the non-skin-side layer 3, which serve as the absorbent layer 10, are joined together and constitute the absorbent layer 10 by a single component. Alternatively, it could be an absorbent article composed of two components, the absorbent layer 10 and the backing sheet 4, as shown in the sanitary napkin 100. Furthermore, it could be like the sanitary napkin 100, which may not necessarily have a side sheet 5. Moreover, other components, such as a sheet material, may be provided between the absorbent layer 10 and the backing sheet 4.

[0238] ===Other Implementation Methods===

[0239] The above-described embodiments are provided for ease of understanding of the present invention and are not intended to limit the interpretation of the present invention. The present invention can be modified and improved without departing from its spirit, and it is self-evident that the present invention includes its equivalents.

[0240] Explanation of reference numerals in the attached figures

[0241] 1. Sanitary napkin (menstrual pad, absorbent); 1w, wings; 2. Skin side layer (absorbent component); 2f, potential shrinkage fiber (fiber); 3. Non-skin side layer; 3f, potential shrinkage fiber (fiber); 4. Backing (outer layer); 5. Side sheet; 10. Absorbent layer; 20. Compression section; DH, high-density section, concave section; DL, low-density section; Ru, skin side area; Rm, middle area; Rd, non-skin side area.

Claims

1. An absorbent article, characterized in that, The absorbent article, in its unfolded state, has a length direction, a width direction, and a thickness direction, and has the following characteristics: The skin side layer, the central portion of which is located in the width direction at the position closest to the skin side; A non-skin side layer, located on the non-skin side compared to the skin side layer; and The liquid-impermeable outer layer is positioned on the non-skin side compared to the non-skin side layer. The skin side layer and the non-skin side layer each have multiple fibers containing potentially curled fibers. In both the skin-side layer and the non-skin-side layer, the plurality of fibers are not fused together.

2. The absorbent article according to claim 1, characterized in that, The non-skin side layer has a linear high-density portion with a higher fiber density than the surrounding area.

3. The absorbent article according to claim 1 or 2, characterized in that, The absorbent article has a recessed portion along the thickness direction on the skin side of the non-skin side layer.

4. The absorbent article according to claim 1 or 2, characterized in that, In the central portion of the width direction, no adhesive is provided between the skin side layer and the non-skin side layer.

5. The absorbent article according to claim 1 or 2, characterized in that, The thickness of the skin side layer is greater than the thickness of the non-skin side layer.

6. The absorbent article according to claim 1 or 2, characterized in that, The skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, The average narrowness of the non-skin-side region in the narrowness evaluation test used to quantitatively evaluate the narrowness of the void is smaller than the average narrowness of the skin-side region in the narrowness evaluation test.

7. The absorbent article according to claim 1 or 2, characterized in that, The skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, The void ratio in the non-skin side region of the void ratio evaluation test, which is used to quantitatively evaluate the proportion of voids in a predetermined region, is smaller than the void ratio in the skin side region of the void ratio evaluation test.

8. The absorbent article according to claim 1 or 2, characterized in that, The hydrophilicity of the skin side layer is lower than that of the non-skin side layer.

9. The absorbent article according to claim 1 or 2, characterized in that, The skin side layer has gaps formed by the plurality of fibers. When the skin side layer is divided into three equal parts along the thickness direction, and the region closest to the skin side is designated as the skin side region, the region closest to the non-skin side is designated as the non-skin side region, and the region between the skin side region and the non-skin side region is designated as the intermediate region, At least a portion of the fibers in the non-skin-side region have higher hydrophilicity than the fibers in the skin-side region. A portion of the fibers in the non-skin-side region are exposed on the skin-side surface of the skin-side region.

10. The absorbent article according to claim 1 or 2, characterized in that, The maximum thickness of the fibers in the skin side layer is greater than the maximum thickness of the fibers in the non-skin side layer.

11. The absorbent article according to claim 1 or 2, characterized in that, The potential coiled fibers of the skin side layer and the non-skin side layer are fibers composed of a single resin.

12. The absorbent article according to claim 1 or 2, characterized in that, The potential coiled fibers of the skin side layer and the non-skin side layer are respectively composed of polyethylene terephthalate fibers.

13. The absorbent article according to claim 1 or 2, characterized in that, With the skin side layer and the non-skin side layer overlapping, the bending stiffness B in the KES method at the central portion of the skin side layer and the non-skin side layer in the length direction and the central portion in the width direction is 1.2 gf·cm. 2 / cm or less.

14. The absorbent article according to claim 1 or 2, characterized in that, With the skin side layer and the non-skin side layer overlapping, the bending hysteresis 2HB at the central portion of the skin side layer and the non-skin side layer in the length direction and the central portion in the width direction in the KES method is 0.93 gf·cm. 2 / cm or less.

15. The absorbent article according to claim 1 or 2, characterized in that, With the skin side layer and the non-skin side layer overlapping, the linearity LC of the compression characteristics of the central portion of the skin side layer and the non-skin side layer in the KES method in the length direction and the central portion in the width direction is 0.6 or more.

16. The absorbent article according to claim 1 or 2, characterized in that, With the skin side layer and the non-skin side layer overlapping, the compressive resilience (RC) in the KES method at the central portion of the skin side layer and the central portion of the non-skin side layer in the length direction and the central portion in the width direction is 38.0% or more.

17. The absorbent article according to claim 1 or 2, characterized in that, With the skin side layer and the non-skin side layer overlapping, the compressive work WC in the KES method at the central portion of the skin side layer and the non-skin side layer in the length direction and the central portion in the width direction is 1.3 gf·cm / cm. 2 above.

18. The absorbent article according to claim 1 or 2, characterized in that, When viewed along the thickness direction, the central portion of the absorbent article in both the length and width directions is defined as a predetermined area. The weight of the predetermined area before absorbing distilled water is set as the weight before absorption. The weight of the predetermined area after immersing it in distilled water for 60 seconds, then pulling it out of the distilled water and suspending it for 90 seconds is defined as the weight after absorption. The value obtained by subtracting the weight before absorption from the weight after absorption is set as the absorbed weight of the distilled water. The value obtained by dividing the absorbed weight by the weight before absorption is 5 or more.

19. The absorbent article according to claim 1 or 2, characterized in that, In an elongation test, with the skin side layer and the non-skin side layer overlapping, the magnitude of the force required to stretch the length of the skin side layer and the non-skin side layer in the longitudinal direction to a length that is 1.3 times the length of the skin side layer and the non-skin side layer in the longitudinal direction is measured. The value obtained by dividing the magnitude of the force measured in the 10th elongation test of the skin side layer and the non-skin side layer by the magnitude of the force measured in the 1st elongation test of the skin side layer and the non-skin side layer is 50% or more.

20. The absorbent article according to claim 1 or 2, characterized in that, The air permeability resistance value is less than 0.32 kPa·s / m when the skin side layer and the non-skin side layer overlap.

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