Nonwoven fabric sheet and absorbent article

Abstract

To provide a nonwoven fabric sheet which easily gives a wearer or the like an impression that the nonwoven fabric sheet is an absorbent article improved in diffusibility and absorbency of an excretion liquid while improving the absorbency of the excretion liquid in the nonwoven fabric sheet.SOLUTION: A nonwoven fabric sheet (3) used in an absorbent article (1), the nonwoven fabric sheet (3) having a longitudinal direction, a lateral direction, and a thickness direction that intersect each other, the nonwoven fabric sheet (3) comprising a plurality of fibers (3f), the nonwoven fabric sheet (3) having a first region (DH) and a second region (DL) as viewed in the thickness direction, the first region (DH) being a linear region extending in the longitudinal direction and having a higher concentration of fibers (3f) than the second region (DL), in addition, the nonwoven fabric sheet (3) is thinner than the second region (DL), and the first region (DH) and the second region (DL) are provided such that the value obtained by dividing the length in the vertical direction of the diffusion region of horse blood in the first region (DH) by the length in the vertical direction of the diffusion region of horse blood in the second region (DL) is 1.5 or more 5 minutes after dropping horse blood of 0. 5ml on the central portion of the nonwoven fabric sheet (3).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric sheet and an absorbent article. [Background technology]

[0002] Conventionally, absorbent articles such as sanitary napkins, disposable diapers, and absorbent pads have been known. For example, Patent Document 1 discloses a sanitary napkin having a topsheet disposed on the skin-contacting side, a backsheet disposed on the non-skin-contacting side, and an absorbent body disposed between the topsheet and the backsheet. The absorbent body in Patent Document 1 is made of pulp fiber or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-176412 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable for absorbent articles such as sanitary napkins described in Patent Document 1 and the like to have good absorbency and diffusibility so as to prevent leakage of body waste. However, even in absorbent articles with improved absorbency and diffusibility, there is a problem in that the absorbency and diffusibility are difficult for the wearer to recognize.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a nonwoven fabric sheet that improves the absorbency of excrement within the nonwoven fabric sheet while easily giving the impression to the wearer that the nonwoven fabric sheet is an absorbent article with improved excrement diffusion and absorption. [Means for solving the problem]

[0006] The main invention for achieving the above object is a nonwoven fabric sheet used in absorbent articles, which has a longitudinal direction, a transverse direction, and a thickness direction that intersect with each other, contains a plurality of fibers, and when viewed in the thickness direction, has a first region and a second region, the first region is a linear region extending in the longitudinal direction, has a higher fiber density than the second region, and is thinner than the second region, and the first region and the second region are arranged so that 5 minutes after 0.5 ml of horse blood is dropped into the center of the nonwoven fabric sheet, the value obtained by dividing the longitudinal length of the horse blood diffusion region in the first region by the longitudinal length of the horse blood diffusion region in the second region is 1.5 or more. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a nonwoven fabric sheet that improves the absorbency of excrement within the nonwoven fabric sheet, while easily giving the impression to the wearer that the nonwoven fabric sheet is an absorbent article with improved diffusion and absorption of excrement. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a sanitary napkin 1 as seen from the skin side. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. [Figure 3] 1A and 1B are diagrams illustrating the configuration of a napkin 1. FIG. [Figure 4] FIG. 2 is a diagram illustrating the absorbent layer 10 of the napkin 1. [Figure 5] 5A is a diagram showing a schematic cross section of the skin side layer 2. FIG. 5B is a diagram showing a schematic cross section of the non-skin side layer 3. [Figure 6] 10 is a diagram illustrating a diffusion region K1 of horse blood in a high density portion DH and a diffusion region K2 of horse blood in a low density portion DL. [Figure 7] FIG. 5 is an enlarged view of a portion X in FIG. [Figure 8]FIG. 8 is a schematic cross-sectional view taken along the arrow BB in FIG. 7. [Figure 9] FIG. 1 is a diagram illustrating a water retention test. [Figure 10] FIG. 10 is a diagram illustrating winding up of the fiber 3f. [Figure 11] The measurement results for each example and comparative example are shown below. DETAILED DESCRIPTION OF THE INVENTION

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings. (Aspect 1) A nonwoven fabric sheet for use in absorbent articles has a longitudinal direction, a transverse direction, and a thickness direction that intersect with each other, contains a plurality of fibers, and when viewed in the thickness direction, has a first region and a second region, the first region is a linear region extending in the longitudinal direction, has a higher fiber density than the second region, and is thinner than the second region, and the first region and the second region are arranged so that 5 minutes after 0.5 ml of horse blood is dropped into the center of the nonwoven fabric sheet, the value obtained by dividing the longitudinal length of the horse blood diffusion region in the first region by the longitudinal length of the horse blood diffusion region in the second region is 1.5 or more.

[0010] According to the nonwoven fabric sheet of aspect 1, the first and second regions are provided such that the value obtained by dividing the vertical length of the horse blood diffusion area in the first region by the vertical length of the horse blood diffusion area in the second region is 1.5 or more. This makes it easier to promote vertical diffusion of excrement in the first region than in the second region of the nonwoven fabric sheet when an absorbent article using the nonwoven fabric sheet is worn, compared to when the first and second regions are provided such that the value obtained by dividing the vertical length of the horse blood diffusion area in the first region by the vertical length of the horse blood diffusion area in the second region is less than 1.5.This improves the absorbency of excrement within the nonwoven fabric sheet, while also giving the impression to the wearer that the absorbent article has improved diffusion and absorption of excrement.

[0011] (Aspect 2) The nonwoven fabric sheet of Aspect 1, wherein the plurality of fibers are not fused to one another.

[0012] Generally, fused fibers tend to hinder the diffusion of liquid and reduce the liquid absorbency and liquid retention. In the nonwoven fabric sheet of aspect 2, the fibers are not fused, which reduces the risk of hindering the diffusion of liquid and reducing the liquid absorbency and liquid retention compared to when the fibers are fused.

[0013] (Aspect 3) The nonwoven fabric sheet of aspect 1 or 2, wherein the plurality of fibers include latent crimp fibers.

[0014] According to the nonwoven fabric sheet of aspect 3, the plurality of fibers have latent crimped fibers, which reduces the risk of the latent crimped fibers absorbing liquid and swelling like pulp fibers. This makes it easier to maintain voids between the fibers, which makes it easier to improve liquid absorbency.

[0015] (Aspect 4) Aspect 3 is a nonwoven fabric sheet, wherein the latently crimped fibers are conjugated fibers in which polyethylene terephthalate and modified polyethylene terephthalate are bonded side-by-side.

[0016] According to the nonwoven fabric sheet of aspect 4, the crimping of the latently crimped fibers tends to narrow the gaps between the fibers, which makes it easier for absorbed liquid to diffuse within the nonwoven fabric sheet due to capillary action.

[0017] (Aspect 5) Aspect 5. The nonwoven fabric sheet of any one of aspects 1 to 4, wherein the average inter-fiber distance in the second region divided by the average inter-fiber distance in the first region is 3.0 or greater.

[0018] According to the nonwoven fabric sheet of aspect 5, the diffusion of excretory fluid in the first region is more easily promoted by capillary action than when the value obtained by dividing the average distance between fibers in the second region by the average distance between fibers in the first region is less than 3.0, thereby improving the absorbency of excretory fluid within the nonwoven fabric sheet and giving the impression to the wearer and others that the article has improved diffusion and absorption of excretory fluid.

[0019] (Aspect 6) The nonwoven fabric sheet according to any one of Aspects 1 to 5 is an absorbent that absorbs liquid.

[0020] The nonwoven fabric sheet of aspect 6 makes it easier to promote the vertical diffusion of absorbed liquid within the nonwoven fabric sheet, thereby improving the absorbency of excretory liquid in the absorbent article and giving the impression to the wearer that the absorbent article has improved excretory liquid diffusion and absorption.

[0021] (Aspect 7) The nonwoven fabric sheet of any one of Aspects 1 to 6, wherein the length in the longitudinal direction of the nonwoven fabric sheet is longer than the length in the transverse direction, and the second region is adjacent to each side of the first region in the longitudinal direction.

[0022] According to the nonwoven fabric sheet of aspect 7, liquid absorbed in the second region located on one side in the longitudinal direction can be easily transferred to the first region by capillary action, and any liquid that has been absorbed in the first region but cannot be completely absorbed is absorbed in the second region located on the other side in the longitudinal direction, which makes it easier to promote the diffusion of liquid in the longitudinal direction of the nonwoven fabric sheet.

[0023] (Aspect 8) The nonwoven fabric sheet of any one of Aspects 1 to 7, wherein the length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the transverse direction, the first region has a portion that is inclined with respect to the longitudinal direction, and the smaller angle between the longitudinal direction and the first region is 45 degrees or less.

[0024] The nonwoven fabric sheet of aspect 8 makes it easier to diffuse absorbed liquid in the longitudinal direction of the nonwoven fabric sheet.

[0025] (Aspect 9) The nonwoven fabric sheet of any one of aspects 1 to 8, wherein the length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the lateral direction, a plurality of the first regions are provided, and the plurality of first regions are spaced apart from each other in the lateral direction.

[0026] The nonwoven fabric sheet of aspect 9 reduces the risk of excreted liquid remaining pooled in the areas where the first regions overlap in the horizontal direction, making it easier to diffuse absorbed liquid in the vertical direction of the nonwoven fabric sheet.

[0027] (Aspect 10) The nonwoven fabric sheet of any one of Aspects 1 to 9, wherein the length in the longitudinal direction of the nonwoven fabric sheet is longer than the length in the transverse direction, and when the length in the longitudinal direction of the nonwoven fabric sheet is divided into thirds and the central portion in the longitudinal direction is defined as the central portion, the first region has a portion that is continuous from the upper end to the lower end of at least the central portion.

[0028] The nonwoven fabric sheet of aspect 10 facilitates the vertical diffusion of liquid at least in the central portion.

[0029] (Aspect 11) 11. The nonwoven fabric sheet of any one of aspects 1 to 10, wherein the average distance between the fibers is 11 to 28 μm.

[0030] The nonwoven fabric sheet of embodiment 11 provides more flow paths for diffusing liquid and more areas for retaining liquid than when the average interfiber distance is less than 11 μm, while also promoting the drawing in and absorption of absorbed liquid by capillary action more easily than when the average interfiber distance is greater than 28 μm.

[0031] (Aspect 12) 12. The nonwoven fabric sheet of any one of Aspects 1 to 11, wherein the first region has a recess with a bottom.

[0032] According to the nonwoven fabric sheet of aspect 12, by having a bottomed recess, when an absorbent article using the nonwoven fabric sheet is worn, it becomes easier to transfer absorbed excrement from the skin side to the non-skin side, which makes it easier to reduce discomfort when wearing the absorbent article.

[0033] (Aspect 13) 13. The nonwoven fabric sheet of any one of Aspects 1 to 12, wherein the basis weight of the fibers of the nonwoven fabric sheet is 80 gsm or more and 140 gsm or less.

[0034] According to the nonwoven fabric sheet of embodiment 13, the nonwoven fabric sheet is more likely to absorb liquid than when the fiber basis weight of the nonwoven fabric sheet is less than 80 gsm, and the risk of the nonwoven fabric sheet becoming excessively thick or stiff is reduced compared to when the fiber basis weight of the nonwoven fabric sheet is more than 140 gsm.

[0035] (Aspect 14) 14. The nonwoven fabric sheet of any one of aspects 1 to 13, wherein the nonwoven fabric sheet is placed in the crotch area of ​​a wearer when the absorbent article is worn.

[0036] According to the nonwoven fabric sheet of embodiment 14, when the nonwoven fabric sheet absorbs excreted liquid, the excreted liquid is more easily dispersed within the nonwoven fabric sheet, thereby reducing discomfort caused by excreted liquid leaking or being retained in a localized area.

[0037] (Aspect 15) 15. The nonwoven fabric sheet of any of Aspects 1 to 14, wherein the weight of the nonwoven fabric sheet before absorbing a liquid is defined as a pre-absorption weight, the weight of the nonwoven fabric sheet after immersing the nonwoven fabric sheet in distilled water for 60 seconds and then removing it from the distilled water and hanging it for 90 seconds is defined as a post-absorption weight, and the value obtained by subtracting the post-absorption weight from the pre-absorption weight is defined as the weight of distilled water retained by the nonwoven fabric sheet, wherein the value obtained by dividing the retained weight by the pre-absorption weight is 8 or more.

[0038] According to the nonwoven fabric sheet of embodiment 15, the absorbent article can retain more excrement than when the weight of distilled water retained by the nonwoven fabric sheet divided by the weight before absorption is set to less than 8, thereby reducing the risk of excrement leaking from absorbent articles using the nonwoven fabric sheet.

[0039] (Aspect 16) Aspect 3 is a nonwoven fabric sheet comprising at least one latently crimped fiber whose winding direction is inclined at an angle θ of more than 55 degrees relative to the axial direction.

[0040] According to aspect 16, even if there is at least one latent crimped fiber whose winding direction is inclined at an angle θ of more than 55 degrees relative to the axial direction, the absorbency of excreted liquid within the nonwoven fabric sheet is improved, and the wearer is more likely to get the impression that the absorbent article has improved diffusion and absorption of excreted liquid.

[0041] (Aspect 17) The absorbent article of any one of aspects 1 to 15 is characterized in that it has a liquid-impermeable non-skin-side sheet provided on the non-skin side of the nonwoven fabric sheet, and the nonwoven fabric sheet has a portion that abuts the non-skin-side sheet.

[0042] According to the absorbent article of aspect 17, the diffusion state of the excrement absorbed by the nonwoven fabric sheet can be easily seen from the non-skin side of the absorbent article, making it easier for the wearer to recognize that the absorbent article is equipped with a nonwoven fabric sheet with improved diffusion properties.

[0043] === Implementation form === An embodiment of the absorbent article according to the present invention will be described using a sanitary napkin 1 (hereinafter also referred to as "napkin 1") as an example. However, the absorbent article according to the present invention may also be a pants-type disposable diaper or tape-type disposable diaper for adults or infants, sanitary shorts, sanitary napkin, light incontinence pad, absorbent pad, disposable diaper or absorbent sheet for animals, drip sheet, etc. Hereinafter, a person wearing an absorbent article such as napkin 1 or a person who intends to put the absorbent article on someone will also be referred to as a "wearer, etc." In the case of drip sheets, etc., the "wearing state" in the following embodiments will become a "use state," and the wearer will become a "user, etc." Hereinafter, the wearing state will also be referred to as a "use state," and the wearer will also be referred to as a "user, etc."

[0044] <<<Components of sanitary napkin 1>>> FIG. 1 is a plan view of a sanitary napkin 1 (hereinafter also referred to as "napkin") as seen from the skin side. FIG. 2 is a schematic cross-sectional view of the napkin 1 taken along the line AA. FIG. 3 is a diagram illustrating the configuration of the napkin 1. The napkin 1 has a longitudinal direction, a width direction, and a thickness direction, which are perpendicular to one another. In the thickness direction, the side that contacts the wearer's skin is the skin side, and the opposite side is the non-skin side. The skin side in the thickness direction is the side that receives excrement (liquid) when worn. The longitudinal direction of the napkin 1 is aligned with the longitudinal direction of the non-skin side layer 3, which will be described later, and the width direction of the napkin 1 is aligned with the transverse direction of the non-skin side layer 3. The center line CC shown in FIG. 1 etc. indicates the center (central position) of the napkin 1 in the width direction.

[0045] The napkin 1 has a skin-side layer (nonwoven fabric sheet) 2, a non-skin-side layer (nonwoven fabric sheet) 3, a back sheet 4, and a side sheet 5. As shown in Figure 3 etc., the napkin 1 is stacked in the thickness direction in the following order from the skin side: side sheet 5, skin-side layer 2, non-skin-side layer 3, and back sheet 4. The components stacked in the thickness direction are appropriately fixed together with an adhesive such as a hot melt adhesive.

[0046] The skin-side layer 2 is the skin-side sheet located closest to the skin in the widthwise center of the napkin 1, and is an absorbent member that contacts the excretory opening and receives excrement discharged from the excretory opening when the napkin 1 is worn. The skin-side layer 2 is substantially rectangular in shape, with its longitudinal length L2 being longer than its width W2. By providing the skin-side layer 2 in the crotch area of ​​the wearer when the napkin 1 is worn, when the napkin 1 absorbs excrement, the skin-side layer 2 can absorb the excrement and diffuse the absorbed excrement toward the non-skin-side layer 3. This reduces discomfort to the wearer caused by excrement leaking from the napkin 1 or excrement remaining locally on the surface of the skin-side layer 2, for example.

[0047] The non-skinside layer 3 is a nonwoven fabric sheet provided between the skinside layer 2 and the backsheet 4 in the thickness direction. The non-skinside layer 3 is slightly smaller than the skinside layer 2 in a plan view. The non-skinside layer 3 has a generally rectangular shape that is long in the longitudinal direction, with the longitudinal length L3 being longer than the widthwise length W3. The non-skinside layer 3 is an absorbent member that absorbs excrement migrated (diffused) from the skinside layer 2 and retains the excrement. By providing the non-skinside layer 3 in the crotch area of ​​the wearer when the napkin 1 is worn, when the napkin 1 absorbs excrement, the non-skinside layer 3 can absorb the excrement and diffuse it within the non-skinside layer 3. This reduces discomfort to the wearer caused by excrement leaking from the napkin 1 or excrement remaining locally on the surface of the skinside layer 2, for example.

[0048] The skin-side layer 2 and the non-skin-side layer 3 are nonwoven fabrics (nonwoven fabric sheets) composed of latently crimped fibers 2f and latently crimped fibers 3f (see FIG. 5), respectively. In this embodiment, the skin-side layer 2 and the non-skin-side layer 3 are nonwoven fabric sheets formed solely of latently crimped fibers (100% latently crimped fibers). However, the layers (nonwoven fabrics) constituting the skin-side layer 2 and the non-skin-side layer 3 may contain, in addition to latently crimped fibers, fibers made of polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters (PET and PBT), polyamides, etc., composite fibers thereof, as well as hydrophilic fibers such as rayon, pulp, and cotton. Hereinafter, the latently crimped fibers 2f and latently crimped fibers 3f will also be simply referred to as "fibers 2f" and "fibers 3f."

[0049] A "nonwoven fabric" is a fiber sheet, web, or batt in which fibers are oriented unidirectionally or randomly and are bonded by entanglement, fusion, and / or adhesion (JIS L0222:2001, Nonwoven Fabrics, 101). In other words, a nonwoven fabric is a sheet in which fibers are integrated without being woven, with a breaking strength of 5 [N] / 25 mm or more. Breaking strength can be measured by well-known methods, for example, as follows: A tensile tester (Shimadzu Corporation: Autograph, AGS-1kNG) equipped with a load cell with a maximum load capacity of 50 N is used. When measuring the separation strength of a nonwoven fabric sheet, one chuck grips the leading edge of one side of the nonwoven fabric sheet in the longitudinal or lateral direction, and the other chuck grips the other side of the nonwoven fabric sheet. Using a tensile tester, the two chucks are pulled at a constant speed (e.g., 100 mm / min) so that the distance between them increases, while the load applied to the two chucks is measured. The load at which the nonwoven fabric sheet breaks is taken as the breaking strength.

[0050] Examples of nonwoven fabrics include nonwoven fabrics obtained by the meltblown method (meltblown nonwoven fabric), nonwoven fabrics obtained by the electrospinning method (electrospun nonwoven fabric), nonwoven fabrics obtained by the spunbonding method (spunbond nonwoven fabric), nonwoven fabrics produced by the air-through method (air-through nonwoven fabric), nonwoven fabrics produced by the spunlace method (spunlace nonwoven fabric), nonwoven fabrics produced by the needlepunch method (needlepunch nonwoven fabric), laminates of two or more of these nonwoven fabrics, or laminates of these nonwoven fabrics with other nonwoven fabrics or other materials. The skin side layer 2 and the non-skin side layer 3 of this embodiment are each a spunlace nonwoven fabric in which fibers are entangled by a water flow without using an adhesive.

[0051] The nonwoven fabric sheet of the skin side layer 2 of the napkin 1 of this embodiment is formed by the spunlace method described below. (a) First, the hydrophilic fibers 2fb are processed by a carding machine or the like to form a non-skin-side fiber web in the form of a carded web or the like. (b) Next, the hydrophobic fiber 2fa is processed using a carding machine or the like to produce a skin-side fiber web in the form of a carded web or the like, which is then fed onto the non-skin-side fiber web while the non-skin-side fiber web is being transported, and laminated to obtain a laminated web. (c) A high-pressure water jet treatment such as a water jet is applied to the skin side of the laminated web to entangle the fibers between the fiber layers and the fibers of each web, thereby obtaining a laminate. (d) Finally, the laminate is placed in a dryer and heated to a temperature at which the potentially crimpable fibers can crimp, yielding an integrated nonwoven fabric sheet (skin side layer 2). This nonwoven fabric sheet has voids formed by the multiple fibers 2f.

[0052] The nonwoven fabric sheet of the non-skinside layer 3 of the napkin 1 of this embodiment is formed in the same manner as the nonwoven fabric sheet of the skinside layer 2. However, the nonwoven fabric sheet of the non-skinside layer 3 differs from the skinside layer 2 in that it does not use hydrophobic fibers and is made by laminating only a web of hydrophilic fibers.

[0053] Potentially crimped fibers 2f and 3f are fibers that crimp upon heat treatment to develop a helical shape. Potentially crimped fibers are fibers that, when viewed in the thickness direction (cross section), form a coiled shape (a 360-degree spiral shape, such as a circle or ellipse). Potentially crimpable fibers 2f and 3f can be, for example, side-by-side composite fibers in which high-shrinkage and low-shrinkage components are arranged in parallel, or eccentric core-sheath composite fibers in which the high-shrinkage component is the core and the low-shrinkage component is the sheath, with the centers of gravity of the two components not overlapping. When the crimp of the potentially crimpable fiber is developed, the potentially crimpable fiber crimps into a coiled spiral shape.

[0054] The resins with different thermal shrinkage rates or thermal expansion coefficients that form the latently crimped fibers 2f and 3f can be any combination of resins with different thermal shrinkage rates or thermal expansion coefficients, and may be a combination of the same or a single resin, or a combination of different resins. Specific examples of combinations of resins with different thermal shrinkage rates or thermal expansion coefficients that form the latently crimped fibers include a combination of polyester resins or a combination of polyamide resins.

[0055] The nonwoven fabrics of the skin-side layer 2 and the non-skin-side layer 3 of this embodiment each use a combination of polyester-based resins (single-component resins), specifically, a latent crimp fiber of a combination of polyethylene terephthalate (PET) and modified PET (modified polyethylene terephthalate). Modified PET is PET modified by copolymerizing the PET components ethylene glycol and terephthalic acid with a minor component of a diol component other than ethylene glycol or a dicarboxylic acid component other than terephthalic acid. Specific examples of diol components other than ethylene glycol include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyethylene glycol, and polytetramethylene glycol. Specific examples of dicarboxylic acid components other than terephthalic acid include isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, and sebacic acid. A web made of latently crimpable fibers that are a combination of PET and modified PET is then formed using a web-forming means such as a carding machine, and the fibers in this web are entangled using a spunlace method to form a nonwoven fabric. This is then heated to a predetermined temperature to induce crimping in the latently crimpable fibers, thereby producing the nonwoven fabrics for the skin side layer 2 and the non-skin side layer 3. Due to this crimping of the fibers, the basis weight of the latently crimped fibers in the nonwoven fabric after heating is greater than the basis weight of the latently crimpable fibers in the nonwoven fabric before heating. In other words, the crimping of the latently crimpable fibers causes the nonwoven fabric to shrink, increasing the basis weight of the fibers.

[0056] The skin-side layer 2 and the non-skin-side layer 3 are each an absorbent layer 10 having a predetermined thickness and being liquid-permeable and capable of absorbing and retaining liquid. Fig. 4 is a diagram illustrating the absorbent layer 10 of the napkin 1. In the napkin 1, the skin-side layer 2 is a skin-side sheet that contacts the wearer's skin and is a member that first receives excrement when worn, absorbs the received excrement within the skin-side layer 2, and then allows it to permeate toward the non-skin-side layer. The non-skin-side layer 3 is a member that absorbs and retains excrement that has permeated from the skin-side layer 2.

[0057] As shown in FIG. 5, the skin-side layer 2 and the non-skin-side layer 3 each have voids formed by a plurality of fibers (latently crimped fibers) 2f, 3f. FIG. 5A is a schematic diagram showing the cross section of the skin-side layer 2, and FIG. 5B is a schematic diagram showing the cross section of the non-skin-side layer 3. The dimensions in FIGS. 5A and 5B are not necessarily accurate. The voids in the skin-side layer 2 and the non-skin-side layer 3 may be voids between discontinuous fibers (a plurality of fibers), voids formed by a single continuous fiber that is curved or spiral, or a combination of these. The voids formed by a plurality of fibers 2f, 3f refer to spaces or regions in the skin-side layer 2 and the non-skin-side layer 3 where a plurality of fibers 2f, 3f are not present. The voids may not only be spaces surrounded by the fibers 2f, 3f or spaces closed by the fibers, but also at least partially open spaces formed by the fibers 2f, 3f.

[0058] The skin-side layer 2 and the non-skin-side layer 3 each contain latently crimped fibers 2f and 3f, and the crimping of the fibers 2f and 3f causes the fibers 2f and 3f to form a spiral shape that intertwines and threads between them. For example, the distance between the fibers 2f and 3f and the fibers 2f and 3f may be shortened by crimping, or other fibers may be inserted between the shortened fibers 2f and 3f and the fibers 2f and 3f, further reducing the gap between the fibers 2f and 3f and the fibers 2f and 3f. Therefore, the gaps formed by the fibers 2f and 3f, including the latently crimped fibers, are smaller than the gaps formed by multiple fibers in a typical nonwoven fabric made of uncrimped fibers.

[0059] Furthermore, the latently crimped fibers 2f, 3f provided in the skinside layer 2 and the non-skinside layer 3, respectively, are resistant to absorbing liquid themselves. For example, fibers such as pulp fibers absorb liquid (excrement) and increase in diameter, but the latently crimped fibers 2f, 3f in the skinside layer 2 and the non-skinside layer 3 are resistant to absorbing liquid into their interior, even when they come into contact with liquid. Therefore, in the skinside layer 2 and the non-skinside layer 3, even when the napkin 1 absorbs excrement while being worn, the latently crimped fibers 2f, 3f in the skinside layer 2 and the non-skinside layer 3 are resistant to increasing in diameter. Because the fibers are resistant to increasing in diameter, the voids formed by the fibers 2f, 3f are resistant to decreasing in size and are resistant to collapse. As a result, the skin side layer 2 and the non-skin side layer 3 can retain liquid (excrement) in the voids formed by the fibers 2f, 3f, making the skin side layer 2 and the non-skin side layer 3 layers permeable to liquid as well as capable of absorbing and retaining liquid. Furthermore, the skin side layer 2 and the non-skin side layer 3 are nonwoven fabric sheets formed from the fibers 2f, 3f, respectively, and have voids formed by the fibers 2f, 3f, so they are also highly breathable, reducing stuffiness and rough skin that the wearer may experience when wearing the garment and improving comfort when worn.

[0060] As described above, the latently crimped fibers 2f in the skin-side layer 2 are latently crimpable fibers that are a combination of PET and modified PET, and the fibers are of the same thickness throughout. In this embodiment, the latently crimped fibers 2fa have a thickness of 2.2 dtex. The basis weight of the skin-side layer 2 is approximately 170 gsm. It is also preferable to use hydrophobic fibers on the skin-side side of the skin-side layer 2 and hydrophilic fibers on the non-skin-side side.

[0061] The basis weight of the non-skin side layer 3 in this embodiment is approximately 140 gsm. The basis weight of the fibers 3f of the non-skin side layer 3 is preferably 80 gsm or more and 140 gsm or less. This allows more voids to be formed in the non-skin side layer 3 than when the basis weight of the fibers 3f of the non-skin side layer 3 is less than 80 gsm, making the non-skin side layer 3 more likely to absorb liquid. On the other hand, this reduces the risk of the non-skin side layer 3 becoming excessively thick or stiff compared to when the basis weight of the fibers 3f of the non-skin side layer 3 is greater than 140 gsm.

[0062] The latently crimped fibers 3f in the non-skin side layer 3 are latently crimpable fibers made of a combination of PET and modified PET, and have the same diameter throughout the thickness direction. In this embodiment, the diameter of the latently crimped fibers 3f in the non-skin side layer 3 is 2.2 dtex.

[0063] The back sheet 4 is a liquid-impermeable sheet (non-skin-side sheet) arranged on the non-skin-side side of the non-skin-side layer 3. An example of the liquid-impermeable sheet is a polyethylene (PE) resin film. The side sheets 5 are sheets that extend outward from both widthwise sides of the skin-side surface of the skin-side layer 2. Examples of the side sheets 5 include a hydrophobic air-through nonwoven fabric and a hydrophobic spunbond nonwoven fabric.

[0064] The napkin 1 also has a pair of wing portions 1w extending outward in the width direction at approximately the center in the longitudinal direction. The wing portions 1w are formed by side sheets 5 and a back sheet 4. The napkin 1 does not necessarily have to have wing portions 1w. If the napkin 1 does not have wing portions 1w, it may or may not have side sheets 5.

[0065] The napkin 1 also has compressed sections 20 in which the skin side layer 2 and the non-skin side layer 3 are recessed in the thickness direction. The compressed sections 20 fix the positions of the skin side layer 2 and the non-skin side layer 3 and improve the liquid dispersibility of the napkin 1.

[0066] In the compressed portion 20, the thickness of the napkin 1 is thinner than in the surrounding area, and the fiber density of the napkin 1 (skin side layer 2 and non-skin side layer 3) is higher. These comparisons can be made by well-known methods. The thickness of the napkin 1 can be compared by visual comparison, or by using a dial thickness gauge ID-C1012C manufactured by Mitutoyo Corporation or an equivalent instrument to measure the thickness of the target area at, for example, 3.0 gf / cm. 2 An example of a method for comparing the density of napkins 1 is to compare the density of napkins 1 based on images of a cross section of napkin 1 cut in the thickness direction, enlarged using an electron microscope or the like. The shape of compressed portions 20 is not limited to that shown in Figure 1. For example, a plurality of discretely arranged point-like compressed portions may also be used.

[0067] <<<About the non-skin-facing layer 3>>> The non-skinside layer 3 is a nonwoven fabric sheet used in the napkin 1 (absorbent article). The non-skinside layer 3 has a longitudinal direction, a transverse direction, and a thickness direction that intersect with one another, with the longitudinal direction of the non-skinside layer 3 running along the longitudinal direction of the napkin 1, the transverse direction of the non-skinside layer 3 running along the width direction of the napkin 1, and the thickness direction of the non-skinside layer 3 running along the thickness direction of the napkin 1. Hereinafter, the longitudinal direction of the non-skinside layer 3 will also be referred to as the "longitudinal direction," and the transverse direction of the non-skinside layer 3 will also be referred to as the "width direction."

[0068] The non-skin side layer 3 is a nonwoven fabric sheet formed by integrating fibers without weaving them into a sheet shape. In this embodiment, a plurality of fibers 3f are entangled by a predetermined method to form the sheet shape.

[0069] The absorbent body (absorbent core) of a typical absorbent article is formed from liquid-absorbent fibers such as pulp fibers, SAP, polymer foam structures, etc. For example, an absorbent body (absorbent core) formed from liquid-absorbent fibers such as pulp fibers is simply a laminate of liquid-absorbent fibers, and the fibers are not intertwined with each other. As a result, voids formed by multiple fibers are difficult to maintain their shape. When liquid is absorbed, not only do the liquid-absorbent fibers themselves become thicker, but the voids also easily lose their shape, making it difficult for the voids to absorb liquid. Furthermore, because the liquid-absorbent fibers themselves absorb liquid, the voids are easily crushed. Furthermore, absorbent cores formed from liquid-absorbent fibers such as pulp fibers have a breaking strength of less than 5 [N] / 25 mm, and are therefore more susceptible to deformation and breakage than nonwoven fabric sheets (non-skin-side layer 3). As such, absorbent bodies formed from liquid-absorbent fibers tend to lose their shape when absorbing liquid, making the absorbent body prone to twisting and a decrease in strength.

[0070] In contrast, the non-skinside layer 3 made of a nonwoven fabric sheet is a nonwoven fabric whose shape is maintained by the entanglement of multiple fibers, and therefore the shape of the voids formed by the multiple fibers is easily maintained. Therefore, when the non-skinside layer 3 is used as an absorbent body of a napkin 1, the voids are likely to retain liquid. Furthermore, by maintaining the shape of the voids through entanglement, even when liquid is absorbed, distortion of the shape of the non-skinside layer 3 (absorbent body) can be reduced, making it easier for the shape of the non-skinside layer 3 to be maintained. Therefore, even when the napkin 1 is worn for a long time or when bodily excrement is absorbed multiple times, deformation of the napkin 1 (non-skinside layer 3) can be reduced. Furthermore, because the napkin 1 has voids formed by the fibers 3f, it is more breathable than the absorbent bodies of general absorbent articles.

[0071] The non-skinside layer 3 is used in the napkin 1 as an absorbent that absorbs liquid. Generally, absorbents in absorbent articles such as the napkin 1 can absorb more excreted liquid by diffusing the absorbed excreted liquid over a wide area within the absorbent rather than absorbing it in a single area when the absorbent article is worn. This improves the absorbency of excreted liquid and reduces the risk of excreted liquid remaining on the skin-side surface of the absorbent article, which can cause discomfort to the wearer's skin, compared to when the absorbent article is partially absorbed. While improved diffusion in the non-skinside layer 3 is preferable, because the width of the napkin 1 and the non-skinside layer 3 is shorter than the length of the length, it is preferable that the absorbent in an absorbent article such as the napkin 1 promotes diffusion in the longitudinal direction. Furthermore, it is more preferable that the wearer or the like can recognize the improved absorbency and diffusion of excreted liquid in an absorbent article such as the napkin 1.

[0072] Therefore, the non-skin-side layer 3 of the napkin 1 has a high-density region (first region) DH and a low-density region (second region) DL that have the following characteristics, so that 5 minutes after 0.5 mL of horse blood is dropped onto the center of the non-skin-side layer 3 (nonwoven fabric sheet), the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density region DH divided by the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density region DL is 1.5 or more (LK1 / LK2≧1.5). This improves the absorbency and diffusibility of excrement in the napkin 1 while making it easier for the wearer to recognize that the absorbency and diffusibility have been improved.

[0073] The longitudinal length LK1 of the diffusion region K1 and the longitudinal length LK2 of the diffusion region K2 are obtained by the following horse blood drop test. Figure 6 is a diagram explaining the horse blood diffusion region K1 in the high density part DH and the horse blood diffusion region K2 in the low density part DL.

[0074] <Horse blood drop test> First, the non-skin side layer 3 (nonwoven fabric sheet) is placed on a horizontal surface as a sample. In the present embodiment, when the non-skin side layer 3 is used in a napkin 1, the non-skin side layer 3 is removed from the napkin 1, and a sample of a predetermined size is cut from the removed non-skin side layer 3 and placed on a horizontal surface. In this embodiment, the non-skinside layer 3 removed from the napkin 1 was cut into a rectangular shape measuring 120 mm in length and 35 mm in width, and this was used as the sample. The sample onto which horse blood is dropped may be the same shape and size as the non-skinside layer 3 used in absorbent articles such as the napkin 1, or may be cut to any size. In this embodiment, the non-skinside layer 3 removed from the napkin 1 and cut into a rectangular shape measuring 120 mm in length and 35 mm in width is used as the sample to be measured.

[0075] Next, 0.5 ml of horse blood is dropped onto the center of the sample using a pipetter. Specifically, horse blood warmed to 38°C is dropped onto the center of the sample from a position 5 mm away from the surface of the sample in a perpendicular direction toward the center of the sample. The horse blood used in this embodiment is a product named "Defibrinated Horse Blood (Made in Japan) 100ml" (product number: 003-574, manufactured by Japan Bioserum Co., Ltd.). If the dropped horse blood reaches the vertical or horizontal end of the sample, the diffusion area K may not be measured correctly. On the other hand, if too little horse blood is dropped, the diffusion area K is more likely to vary, and accurate measurement results may not be obtained. Therefore, by dropping 0.5 ml of horse blood onto the sample, it is easier to accurately obtain the diffusion area K and the longitudinal lengths LK1 and LK2 of the diffusion area K than when the amount of horse blood is more than 0.5 ml or less than 0.5 ml.

[0076] Then, the length of each of the diffusion regions K of the horse blood is measured 5 minutes after the dropping. Regarding the measurement of the diffusion region K, the longitudinal length LK1 of the diffusion region K1 in the high-density region DH and the longitudinal length LK2 of the diffusion region K2 in the low-density region DL are measured. Since the high-density region DH is thinner than the low-density region DL, the longitudinal length LK1 of the thinner portion is measured as the diffusion region K1 in the high-density region DH, and the longitudinal length LK2 of the thicker portion is measured as the diffusion region K2 in the low-density region DL. In this case, the longitudinal lengths LK1 and LK2 refer to the lengths from the frontmost end to the rearmost end of each diffusion region K1 and K2 in the longitudinal direction.

[0077] The results of the measurement of the diffusion area using horse blood in this horse blood drop test can be assumed to show a diffusion state similar to that of the diffusion area of ​​human excrement (for example, menstrual blood).

[0078] As described above, the non-skin side layer 3 has a plurality of fibers 3f in the high density portion DH and the low density portion DL. As shown in Fig. 4 and Fig. 7, the high density portion DH is a linear region extending in the longitudinal direction. Fig. 7 is an enlarged view of portion X in Fig. 4. The high density portion DH has a higher density of fibers 3f than the surrounding area (low density portion DL).

[0079] The "linear" high-density portion DH is not limited to a linearly continuous portion where the portions have a higher density than the surrounding area. When multiple high-density portions are arranged intermittently in a line or dots, the linear high-density portion DH also includes the area between the adjacent multiple high-density portions. The area between the adjacent multiple high-density portions that are close to each other has a lower fiber density than the portion formed as a high-density portion, but is an area with a higher fiber density than the surrounding area, so the entire area becomes a linear high-density portion.

[0080] The high-density portion DH is thinner than the surrounding (low-density portion DL). As shown in FIG. 8, in the napkin 1 of the present embodiment, the length (thickness) 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 (thickness) 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). FIG. 8 is a schematic cross-sectional view taken along the line B-B in FIG. 7. 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 by a well-known method. For example, the above-described method of visually comparing, a measuring method using a dial thickness gauge ID-C1012C manufactured by Mitutoyo Corporation or an equivalent thereof, or a microscope (manufactured by Keyence Corporation, VHX-1000) can be used to take a magnified photograph of the cross-section of the non-skin side layer 3 with a known dimension to measure each thickness of the non-skin side layer 3.

[0081] The high-density portion DH can be formed, for example, in the manufacturing process of the non-skin side layer 3 by conveying a non-woven fabric sheet having a substantially uniform thickness in the thickness direction (the non-skin side layer 3 in a state where the high-density portion DH is not formed) while sandwiching it between a pair of rolls. Of the pair of rolls, one roll is a heat embossing roll (or a sonic embossing roll) having convex portions on its outer peripheral surface, and the other roll is an anvil roll having a smooth outer peripheral surface. By setting the heating temperature of the fibers 3f by the heat embossing roll (or the sonic embossing roll) higher than the softening point of the latent crimped fibers of the fibers 3f of the non-skin side layer 3, the fibers 3f are softened to make them easier to process, and it becomes easier to maintain a form in which the high-density portion DH is thinner than the low-density portion DL.

[0082] When the non-skin side layer 3 has the high-density portion DH and the low-density portion DL having the above-mentioned characteristics, the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density portion DH obtained by the horse blood drop test described above is longer than the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density portion DL, as shown in Figure 6. Furthermore, with respect to the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density portion DH and the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density portion DL, the value obtained by dividing the longitudinal length LK1 of the diffusion region K1 by the longitudinal length LK2 of the diffusion region K2 is 1.5 or more (LK1 / LK2 ≥ 1.5). The non-skin-side layer 3 having such high-density portions DH and low-density portions DL is more likely to promote longitudinal diffusion of excretory fluid such as menstrual blood than widthwise diffusion in the non-skin-side layer 3 than in a non-skin-side layer 3 having high-density portions DH and low-density portions DL such that the longitudinal length LK1 of the diffusion region K1 divided by the longitudinal length LK2 of the diffusion region K2 is less than 1.5. Therefore, when a napkin 1 including this non-skin-side layer 3 is worn, the high-density portions DH more likely promote longitudinal diffusion of excretory fluid absorbed by the non-skin-side layer 3. By improving longitudinal diffusion in this way, the non-skin-side layer 3 can absorb more excretory fluid by diffusing it over a wider area than by absorbing it only in a limited area, thereby improving the absorbency of the napkin 1 as a whole. In addition, by diffusing the excrement absorbed by the non-skin-side layer 3 while reducing the risk of excrement leaking from the outside in the width direction of the napkin 1, the excrement remains on the skin-side of the napkin 1 more than when it is only partially absorbed, reducing the risk of the excrement remaining in contact with the wearer's skin or leaking from the napkin 1 before being absorbed inside the napkin 1.

[0083] Furthermore, the visibility of the diffusion region K1 in the high density portion DH and the diffusion region K2 in the low density portion DL gives the wearer the impression that the napkin 1 has improved diffusion and absorption of excrement.

[0084] Furthermore, as shown in Figure 6, with respect to the horse blood diffusion region K1 in the high-density region DH and the horse blood diffusion region K2 in the low-density region DL obtained by the horse blood drop test, it is more preferable that the widthwise length WK1 of the horse blood diffusion region K1 in the high-density region DH be longer than the widthwise length WK2 of the horse blood diffusion region K2 in the low-density region DL. Because the high-density region DH is a linear region along the longitudinal direction, it is a region that is more likely to promote longitudinal diffusion than widthwise diffusion. Therefore, by making the widthwise length WK1 of the horse blood diffusion region K1 in the high-density region DH longer than the widthwise length WK2 of the horse blood diffusion region K2 in the low-density region DL, horse blood (excrement) in the high-density region DH is more likely to promote longitudinal diffusion than outward diffusion in the width direction, thereby reducing the risk of excrement leaking outward in the width direction when wearing the napkin 1.

[0085] Factors that affect the diffusion area of ​​horse blood in a horse blood drop test of the non-skin side layer 3 include, for example, the area of ​​the high density sections DH and low density sections DL, the number of high density sections DH and low density sections DL, the longitudinal or widthwise lengths of the high density sections DH and low density sections DL, the thickness of the high density sections DH (corresponding to tDH in Figure 7), the basis weight of the high density sections DH and low density sections DL, the density of the fibers 3f of the high density sections DH and low density sections DL, the thickness direction length between the skin side of the high density sections DH and the skin side of the low density sections DL (the depth of the depression in the high density sections DH), the arrangement of the high density sections DH and low density sections DL, the proportion of potentially crimped fibers in the fibers 3f that make up the non-skin side layer 3, the type of fibers other than the potentially crimped fibers 3f and absorbent materials such as superabsorbent polymers contained in the non-skin side layer 3, the amount of fibers other than the potentially crimped fibers 3f and absorbent materials contained in the non-skin side layer 3, and the materials and their proportions that make up the potentially crimped fibers 3f, such as PET / modified PET. From these factors, a factor that satisfies the condition that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH in the non-skin-side layer 3 by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL is 1.5 or more (LK1 / LK2≧1.5) should be selected. Other factors for ensuring that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density portion DH in the non-skin-side layer 3 by the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density portion DL is 1.5 or greater (LK1 / LK2≧1.5) are listed below. The non-skin-side layer 3, the high-density portion DH, and the low-density portion DL may each have one of the following factors, or a combination of two or more of the following factors.

[0086] In the non-skin side layer 3, the plurality of fibers 3f are not fused to each other. As described above, in the manufacturing process of the non-skin side layer 3, the high density portion DH can be formed by sandwiching a nonwoven fabric sheet between a pair of rolls. However, at this time, heat and pressure are applied to the high density portion DH, which may cause the plurality of fibers 3f in the high density portion DH to fuse together. Therefore, it is preferable that the high density portion DH be formed by heating the fibers 3f by one of the pair of rolls, a heat embossing roll (or sonic embossing roll), to a temperature higher than the softening point and lower than the melting point of the latent crimped fibers of the fibers 3f in the non-skin side layer 3. This makes it easier to maintain the shape of the high density portion DH while reducing the risk of the plurality of fibers 3f fusing together.

[0087] Generally, in nonwoven fabric sheets, fused fiber portions are portions where the fibers 3f melt together and solidify, which tends to hinder the diffusion of excrement (liquid). On the other hand, the narrower the gaps between the fibers, the easier it is for excrement (liquid) to diffuse. Therefore, in the high density portion DH, the fibers 3f are not fused together, which reduces the risk of hindering the diffusion of absorbed liquid (excrement) compared to when the fibers are fused together.

[0088] Furthermore, the plurality of fibers 3f in the non-skin side layer 3 comprise latently crimped fibers. Because the non-skin side layer 3 is a nonwoven fabric sheet containing latently crimped fibers, the shape of the plurality of fibers is maintained by intertwining, making it easier to maintain the shape of the voids formed by the plurality of fibers. This reduces the risk of the voids formed by the fibers 3f being crushed by absorbing liquid and expanding, as occurs with pulp fibers, making it easier to maintain the voids. Furthermore, because the latently crimped fibers 3f in the non-skin side layer 3 are crimped in a spiral (coil) shape, the spacing between the fibers 3f tends to be narrow. Furthermore, the high-density portion DH provided in the non-skin side layer 3 makes it easier to create narrow spaces between the fibers 3f. Therefore, after absorbing liquid (excrement), the non-skin side layer 3 maintains the gaps between the fibers 3f, and the capillary action caused by the high density portions DH makes it easier for the liquid to be drawn into the high density portions DH, improving the absorbency of the non-skin side layer 3 and making it easier for the absorbed liquid to diffuse within the non-skin side layer 3.

[0089] Furthermore, the plurality of fibers 3f in the non-skinside layer 3 are preferably composite fibers in which polyethylene terephthalate (PET) and modified PET (modified polyethylene terephthalate) are bonded side-by-side. When the plurality of fibers 3f are such potentially crimped fibers, the potentially crimped fibers are more effectively spirally crimped, and the gaps between the fibers 3f are more easily narrowed. The narrower gaps between the fibers 3f facilitate capillary action to draw excreted fluid absorbed by the napkin 1 into the non-skinside layer 3, facilitating diffusion within the non-skinside layer 3.

[0090] In the non-skinside layer 3, the average distance between the fibers 3f is set to 11 to 28 μm. If the distance between the fibers 3f is too small, it becomes difficult to retain excreted fluid in the gaps between the fibers 3f. Therefore, by setting the average distance between the fibers 3f in the non-skinside layer 3 to 11 μm or more, it becomes easier to ensure flow paths for diffusing fluid and areas for retaining fluid, compared to when the average distance between the fibers 3f in the non-skinside layer 3 is less than 11 μm. On the other hand, if the distance between the fibers 3f is too large, capillary action between the fibers 3f becomes difficult to occur. Therefore, by setting the average distance between the fibers 3f to 28 μm or less, excreted fluid absorbed by the napkin 1 is more easily drawn into the non-skinside layer 3 and its absorption is promoted by capillary action, compared to when the average distance between the fibers 3f is greater than 28 μm.

[0091] Further, the value obtained by dividing the average value of the distance between the fibers 3f in the low density portion DL by the average value of the distance between the fibers 3f in the high density portion DH is set to 3.0 or more. (Average fiber distance in low density section DL / average fiber distance in high density section DH > 3.0) This makes it easier to promote diffusion of excreted fluid in the high-density portions DH by capillary action than when the value obtained by dividing the average distance between the fibers 3f in the low-density portions DL by the average distance between the fibers 3f in the high-density portions DH is less than 3.0. This improves the absorbency of excreted fluid in the non-skin side layer 3, and the non-skin side layer 3 having improved absorbency and diffusibility gives the wearer the impression that the napkin 1 has improved absorbency and diffusibility.

[0092] <Calculation method for inter-fiber distance> The average value of the distance between the fibers 3f can be obtained by a known method. For example, the average value of the distance between the fibers 3f can be obtained by the following formula based on Wrotnowski's assumption. Note that, hereinafter, "inter-fiber distance" refers to the average value of the distance between the fibers.

[0093] The distance between fibers 3f is calculated by measuring the thickness of the non-skinside layer 3 to be measured and applying the result to the following equation (1). First, the non-skinside layer 3 to be measured is cut into a piece measuring 50 mm in the longitudinal direction and 50 mm in the transverse direction to prepare a cut piece of the non-skinside layer 3. This cut piece is sandwiched between the skinside layer 2 and the backsheet 4 to prepare a sanitary napkin using the non-skinside layer 3 to be measured as an absorbent layer. In the prepared sanitary napkin, the thickness of the non-skinside layer 3 is measured at a pressure of 49 Pa. The measurement environment is a temperature of 20±2°C and a relative humidity of 65±5%, and a microscope (Keyence Corporation, VHX-1000) is used as the measuring device. An enlarged photograph of the cross section of the non-skinside layer 3 is then taken. An object with known dimensions is also photographed on the enlarged photograph. A scale is aligned with the enlarged photograph of the cross section of the non-skinside layer 3, and the thickness of the non-skinside layer 3 is measured. The above operation is carried out three times, and the average of the three measurements is taken as the thickness [mm] of the dry non-skin side layer 3. In the case of a laminated product, the boundary is determined from the fiber diameter and the thickness is calculated.

[0094] Next, the inter-fiber distance of the fibers constituting the non-skin side layer 3 to be measured is calculated by the following formula based on Wrotnowski's assumption. The formula based on Wrotnowski's assumption is generally used to calculate the inter-fiber distance of the fibers constituting a nonwoven fabric. According to the formula based on Wrotnowski's assumption, the inter-fiber distance A (μm) is calculated by the thickness h (mm) and basis weight e (g / m 2 ), the fiber diameter d (μm) of the fibers constituting the nonwoven fabric, and the fiber density ρ (g / cm 3 ) can be calculated using the following equation (1).

[0095] The fiber diameter d (μm) is determined by measuring the cross sections of 10 cut fibers using a scanning electron microscope (DSC6200 manufactured by Seiko Instruments Inc.) and averaging the measurements. Fiber density ρ(g / cm 3 ) is measured using a density gradient tube in accordance with the density gradient tube method described in JIS L1015 Chemical Fiber Staple Test Method. Basis weight e(g / m 2) is cut to the specified size (e.g., 0.12m x 0.06m), and after measuring the weight, the basis weight is calculated using the formula below. Weight ÷ Area calculated from given size = Grammage (g / m 2 )

[0096]

number

[0097] The distance between the fibers 3f in the non-skinside layer 3 of the napkin 1 of this embodiment is calculated for each of the high density region DH and the low density region DL based on the above formula (1). For example, the thickness, basis weight, fiber diameter and fiber density of the nonwoven fabric of each of the portions DH and DL in the non-skin side layer 3 can be as follows: [High density part DH] Nonwoven fabric thickness: 0.32 mm Basis weight e:121.00g / m 2 Fiber diameter d of fiber 3f constituting non-skin side layer 3: 17.00 μm Fiber density ρ:1.360g / cm 3 When the inter-fiber distance A is calculated from these values, the inter-fiber distance A in the high density portion DH is 11.75 μm. [Low density part DL] Nonwoven fabric thickness: 0.79 mm Basis weight e:121.00g / m 2 Fiber diameter d of fiber 3f constituting non-skin side layer 3: 17.00 μm Fiber density ρ:1.360g / cm 3 When the inter-fiber distance A is calculated from these values, the inter-fiber distance A in the low density portion DL is 27.92 μm.

[0098] Furthermore, as mentioned above, in absorbent articles such as napkin 1, the width of napkin 1 and the non-skin-side layer 3 is shorter than the length in the longitudinal direction, and therefore, by promoting the diffusion of excreted liquid in the longitudinal direction, the risk of excreted liquid leaking outward in the width direction of napkin 1 when worn can be reduced.

[0099] In the non-skin side layer 3, low-density portions DL are adjacent to both sides of the high-density portion DH in the longitudinal direction. For example, as shown in Fig. 7, a plurality of high-density portions DH are arranged intermittently in the longitudinal direction along an imaginary straight line L of the non-skin side layer 3. The imaginary straight line L is an imaginary straight line extending along and parallel to the longitudinal direction. In addition, low-density portions DL are provided adjacent to each high-density portion DH on the front and rear sides in the longitudinal direction.

[0100] The napkin 1 of this embodiment has a plurality of high density portions DH arranged at predetermined intervals in the width direction, each of which is continuous in the longitudinal direction from the upper end to the lower end of the non-skin side layer 3. As shown in Fig. 7, each high density portion DH along one longitudinal direction has a wavy shape in which convex portions protruding toward one side in the width direction (e.g., the left side) and convex portions protruding toward the other side in the width direction (e.g., the right side) are alternately arranged.

[0101] The high-density portions DH of the non-skin-side layer 3 are easily drawn in by capillary action because the voids formed by the fibers 3f are small due to the high density of the fibers 3f. While the high-density portions DH are easily drawn in, their small voids result in a low liquid retention capacity. The low-density portions DL have larger voids than the high-density portions DH, so they draw in less liquid than the high-density portions DH, but their large voids result in a high liquid retention capacity. For this reason, by providing low-density portions DL on both longitudinal sides of the high-density portions DH of the non-skin-side layer 3, liquid once absorbed (retained) in the low-density portions DL can be easily drawn in from one longitudinal side of the low-density portions DL to the adjacent high-density portions DH. Liquid that is drawn in and not retained in the high-density portions DH can diffuse from one longitudinal side of the high-density portions DH to the adjacent low-density portions DL. Doing this once or multiple times facilitates the longitudinal diffusion of liquid.

[0102] As shown in FIG. 7 and other figures, the non-skin-side layer 3 is provided with a plurality of high-density portions DH. The plurality of high-density portions DH are preferably spaced apart from one another in the width direction. That is, adjacent high-density portions DH do not abut (overlap) each other in the width direction, and continuous low-density portions DL are provided between adjacent high-density portions DH in the width direction. As described above, the high-density portions DH are more likely to absorb excreted liquid than the low-density portions DL due to capillary action. If adjacent high-density portions DH abut each other in the width direction, excreted liquid tends to accumulate in the abutting areas. By arranging the plurality of high-density portions DH spaced apart from one another in the width direction, the risk of excreted liquid accumulating in the overlapping areas of the plurality of high-density portions DH in the width direction can be reduced. Furthermore, the high-density portions DH arranged along the longitudinal direction facilitate the longitudinal diffusion of excreted liquid absorbed by the non-skin-side layer 3.

[0103] Furthermore, the linear high-density portions DH are inclined relative to the longitudinal direction, and have portions where the smaller angle between the longitudinal direction and the high-density portions DH is 45 degrees or less. In the napkin 1, as shown in FIG. 7, the high-density portions DH are inclined relative to the longitudinal direction, and have portions where the smaller angle θ1 between the virtual line L and the high-density portions DH is 45 degrees or less. This makes it easier to promote the liquid absorption in the high-density portions DH and the liquid retention in the low-density portions DL in the longitudinal direction, as described above, compared to when high-density portions DH are provided parallel to the longitudinal direction, thereby facilitating the diffusion of liquid in the longitudinal direction. Note that all of the smaller angles between the longitudinal direction and the high-density portions DH may be 45 degrees or less, or at least one of the smaller angles between the longitudinal direction and the high-density portions DH may be 45 degrees or less, and may have a portion where the angle is greater than 45 degrees.

[0104] When the longitudinal length of the non-skinside layer 3 is divided into thirds, with the front portion of the third divided into the front region 31, the central portion divided into the central region 32, and the rear portion divided into the rear region 33, the high-density portion DH has a portion that continues from the upper end to the lower end of the central region 32. The central region 32 is a region that is likely to come into contact with the excretory opening when worn. By having the high-density portion DH of the non-skinside layer 3 have a portion that continues from the upper end to the lower end of the central region 32, excreted body waste is more likely to be dispersed in the longitudinal direction at least in the central region 32. This reduces the risk of excreta being locally retained in the napkin 1 and the risk of excreta leaking outward in the lateral direction of the napkin 1.

[0105] As shown in FIG. 8, a bottomed recess is formed in the high-density portion DH. In other words, the high-density portion DH does not have any intentionally perforated portions in the thickness direction, unlike the voids formed by the fibers 3f. Even when the high-density portion DH has a bottomed recess, it is still easy to promote liquid diffusion in the non-skinside layer 3. Furthermore, in a napkin 1, where the skinside layer 2 is located closer to the skin than the non-skinside layer 3 and the recess in the non-skinside layer 3 is located on the skin side, the recess in the high-density portion DH is easily separated from the skinside layer 2. This reduces the risk of excrement once absorbed by the non-skinside layer 3 returning to the skinside layer 2, thereby reducing discomfort to the wearer's skin. As shown in FIG. 8, the non-skinside layer 3 of the napkin 1 may have recesses on both the skin-side and non-skin-side surfaces of the non-skin-side layer 3; the skin-side surface may have recesses recessed toward the non-skin side and the non-skin-side surface may be flat; or the skin-side surface of the non-skin-side layer 3 may be flat and the non-skin-side surface may have recesses recessed toward the skin side. Furthermore, when viewed in the thickness direction, the recesses on the skin side and the recesses on the non-skin side may be provided at the same position or at different positions.

[0106] The non-skin side layer 3 has the following water retention rate for distilled water. The weight of the non-skin side layer 30 before absorbing the liquid is defined as the pre-absorption weight (A1). The weight of the non-skin side layer 3 after immersing it in distilled water for 60 seconds and then removing it from the distilled water and hanging it for 90 seconds is defined as the post-absorption weight (A2). The weight (A3) of distilled water retained in the non-skin side layer 3 is calculated by subtracting the weight (A2) after absorption from the weight (A1) before absorption. Weight after absorption (A2) - Weight before absorption (A1) = Retained weight (A3) The water retention rate of the non-skin side layer 3 for distilled water can be obtained by dividing this retained weight (A3) by the weight before absorption (A1). For the non-skin side layer 3, it is preferable that the value obtained by dividing the retained weight (A3) by the weight before absorption (A1) is 8 or more. Retained weight (A3) / weight before absorption (A1)≧8

[0107] <Water retention test> The water retention rate of the non-skinside layer 3 for distilled water can be obtained by the following water retention test. Fig. 9 is a diagram illustrating the water retention test. The water retention test may be performed on the entire non-skinside layer 3 of the napkin 1, or on a sample obtained by cutting the non-skinside layer 3 to a predetermined size. In the following, an example will be described in which a sample 30 obtained by cutting the non-skinside layer 3 to a rectangular shape with a longitudinal length of 120 mm and a width of 35 mm is used.

[0108] First, as shown in FIG. 9A, the weight of the sample 30 before absorbing the liquid is measured to obtain the weight before absorption (A1). Next, as shown in Fig. 9B, the sample 30 is immersed in distilled water for 60 seconds, so that the sample 30 is completely submerged in the distilled water. After immersion for 60 seconds, the sample 30 is taken out of the distilled water and is left suspended for 90 seconds using a clip CP or the like, as shown in FIG. 9C. After hanging for 90 seconds, the sample 30 is weighed to obtain the post-absorption weight (A2). The weight (A3) of the sample 30 retained in distilled water can be obtained by subtracting the weight (A2) after absorption obtained by measurement by the weight (A1) before absorption. The obtained retained weight (A3) is divided by the pre-absorption weight (A1) to obtain the water retention of the sample 30 and the non-skin side layer 3.

[0109] In this way, when the value obtained by dividing the retained weight (A3) by the pre-absorption weight (A1) of the non-skin side layer 3 is 8 or more, the non-skin side layer 3 and the napkin 1 can retain more excrement than when the value obtained by dividing the retained weight (A3) by the pre-absorption weight (A1) is less than 8. This reduces the risk of excrement leaking from a napkin 1 using such a non-skin side layer 3.

[0110] 10, the non-skin side layer 3 includes at least one fiber 3f that is a latently crimped fiber and whose curling direction is inclined at an angle θ2 of more than 55 degrees with respect to the direction of the axis J. Fig. 10 is a diagram illustrating the curling of the fiber 3f. Even when the non-skin side layer 3 includes at least one latently crimped fiber 3f that is inclined at an angle θ2 of more than 55 degrees with respect to the direction of the axis J, it is possible to improve the absorbency of excrement in the non-skin side layer 3 and to give the impression to the wearer that the napkin 1 has improved absorbency and diffusion of excrement.

[0111] As described above, the napkin 1 has a liquid-impermeable backsheet (non-skin-side sheet) 4 provided on the non-skin-side side of the non-skin-side layer 3. The napkin 1 has a portion where the non-skin-side sheet 3 and the backsheet 4 abut. In the napkin of this embodiment, the non-skin-side layer 3 and the backsheet 4 are provided adjacent to each other in the thickness direction and fixed with a hot-melt adhesive or the like. In the napkin 1, the backsheet 4 is a member that constitutes the non-skin-side surface of the napkin 1 and is provided with an adhesive portion on the non-skin-side surface for fixing the napkin 1 to clothing when worn. Having a portion where the non-skin-side layer 3 and the backsheet 4 abut makes it easier to visually confirm the diffusion state of the excrement absorbed by the non-skin-side layer 3 through the backsheet 4 from the non-skin side of the napkin 1 after it has absorbed the excrement. This makes it easier for the wearer to recognize that the napkin 1 has a non-skin-side layer 3 with improved diffusion properties.

[0112] As described above, the napkin 1 has a non-skinside layer 3 and a skinside layer 2 (skinside sheet), with the skinside layer 2 having voids (first voids) formed by a plurality of fibers 2f, and the non-skinside layer 3 having voids (second voids) formed by a plurality of fibers 3f. Regarding each of these voids, the proportion of voids (second voids) in the non-skinside layer 3 in a void ratio evaluation test for quantitatively evaluating the proportion of voids in a predetermined area is preferably smaller than the proportion of voids (first voids) in the skinside layer 2 in the void ratio evaluation test. In the napkin 1, by providing a high-density portion DH throughout the entire non-skinside layer 3, the proportion of voids (second voids) in the non-skinside layer 3 in the void ratio evaluation test is made smaller than the proportion of voids (first voids) in the skinside layer 2 in the void ratio evaluation test. When the napkin 1 absorbs excrement, capillary action tends to draw the excrement from the skin-side layer 2 to the non-skin-side layer 3, which has a smaller proportion of voids, and this tends to promote diffusion of the excrement within the non-skin-side layer 3. In addition, since it tends to reduce the amount of excrement remaining in the skin-side layer 2 when the napkin 1 is worn, it is possible to reduce discomfort caused by excrement coming into contact with the wearer's skin.

[0113] Note that the method of making the proportion of voids (second voids) in the non-skin side layer 3 smaller than the proportion of voids (first voids) in the skin side layer 2 in the void ratio evaluation test is not limited to providing high density portions DL in the non-skin side layer 3. For example, the non-skin side layer 3 may be entirely compressed in the thickness direction to crush the non-skin side layer 3 in the thickness direction, thereby reducing the voids formed by the fibers 3f. The thickness (fiber diameter) of the fibers 3f of the non-skin side layer 3 may be smaller than the thickness (fiber diameter) of the fibers 2f of the skin side layer 2. Furthermore, the fibers 3f of the non-skin side layer 3 may be latently crimped fibers that have a stronger crimping property than the fibers 2f of the skin side layer 2.

[0114] <Void ratio evaluation test method> The void ratio evaluation test for the skin side layer 2 and the non-skin side layer 3 of the napkin 1 of this embodiment was carried out by Toray Research Center, Inc. The void ratio evaluation test can be carried out, for example, by the following method.

[0115] First, X-ray CT measurement is performed on each of the skin-side layer 2 and the non-skin-side layer 3. Non-destructive tomography (CT measurement) is performed under the following conditions using a high-resolution 3D X-ray microscope nano3DX manufactured by Rigaku Corporation. X-ray source: Cu Tube voltage-tube current: 40kV-30mA Detector: sCMOS camera (lens: 1080) Resolution: 2.51μm / voxel

[0116] Measurement areas (predetermined areas) of the skin side layer 2 and the non-skin side layer 3 are randomly extracted from the three-dimensional data obtained by photography, and voids are analyzed. The measurement areas for this analysis are rectangular parallelepipeds (or cubes) whose thickness direction lengths are the thicknesses H2 and H3 of the skin side layer 2 and the non-skin side layer 3 within any range in the planar direction of the skin side layer 2 and the non-skin side layer 3.

[0117] The tomographic image obtained by X-ray CT shows low-density (void) components that easily transmit X-rays in black, and high-density (fiber) components that easily absorb X-rays in white. From this image, the void ratios of the measurement areas of the skin-side layer 2 and non-skin-side layer 3 are calculated.

[0118] The void ratios of the skin side layer 2 and the non-skin side layer 3 can be calculated by obtaining the void volume and the volume of the measurement area in the skin side layer 2 and the non-skin side layer 3 from the tomographic image obtained by X-ray CT. For example, the void ratio of the non-skin side layer 3 is as follows: Void ratio of non-skin side layer 3=(void volume of non-skin side layer 3) / (volume of non-skin side layer 3) The volume of the non-skin side layer 3 is the sum of the volume of the fibers in the non-skin side layer 3 and the volume of the voids in the non-skin side layer 3 .

[0119] In the napkin 1 of the above-described embodiment, an adhesive such as a hot melt adhesive is provided between the components stacked in the thickness direction to secure the components together, but this is not limited to this. An adhesive need not be provided between the skinside layer 2 and the non-skinside layer 3. In particular, an adhesive need not be provided between the skinside layer 2 and the non-skinside layer 3 in the central portion of the napkin 1 in the width direction. This reduces the risk that the adhesive will interfere with the absorption of excrement in the skinside layer 2 and the non-skinside layer 3, and also reduces the risk that the adhesive will interfere with the diffusion of excrement from the skinside layer 2 to the non-skinside layer 3, thereby reducing the risk that excrement will remain in the skinside layer 2.

[0120] Below, we will explain in detail several examples and comparative examples in which the conditions of the high-density section DH and the low-density section DL of the non-skin-side layer 3 (nonwoven fabric sheet) are changed, but the present invention is not limited to these examples. FIG. 11 shows the measurement results for each of the examples and comparative examples. In the following, measurements were carried out on Examples A to F, which are nonwoven fabric sheets usable as the non-skin side layer 3, and Comparative Examples 1 and 2, which are sheets corresponding to the non-skin side layer 3, each having a rectangular shape with a longitudinal length of 120 mm and a lateral length of 35 mm. Each of Examples A to F and Comparative Examples 1 and 2 is formed using only potentially crimped fibers (fibers 3f), and the nonwoven fabric sheets are formed using the same amount and weight of fibers 3f. Each of Examples A to F and Comparative Example 2 has a high-density portion DH with a shape similar to that shown in Figures 4, 7, etc. However, the thicknesses of the high-density portion DH and the low-density portion DL are different in Examples A to F and Comparative Example 2. The thickness, inter-fiber distance, horse blood drop test, and water retention test in FIG. 11 each show the results of measurements made using the methods described above. The thickness of the low density portion DL is the average value of the results of measuring the thickness of the thickest part of each nonwoven fabric sheet eight times, and the thickness of the high density portion DH is the average value of the results of measuring the thickness of the thinnest part of each nonwoven fabric sheet eight times. The inter-fiber distance is calculated from the measured thickness of the low density part DL and the measured thickness of the high density part DH, and is the average inter-fiber distance calculated from the average inter-fiber distance from the results of eight measurements. The results of the water retention test are the average of three measurements.

[0121] Example A In the nonwoven fabric sheet of Example A, the high density portion DH is formed by batch production, not by a pair of rolls. The measurement results for the nonwoven fabric sheet of Example A are as follows. Low density part DL thickness: 1.21 mm Fiber distance in low density section DL: 46 μm Thickness of high density part DH: 0.3 mm Distance between fibers in high density section DH: 22.9 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 2.0 <Horse blood drop test> The longitudinal length LK1 of the diffusion area K1 in the high density part DH: 90.5 mm The longitudinal length LK2 of the diffusion region K2 of the low-density part DL: 29.5 mm LK1 / LK2:3.07 <Water retention test> Weight before absorption: 0.557g Weight after absorption: 3.831g Holding weight: 3.274g Water retention rate: 5.88 It is clear that the thickness of the high density portion DH along the longitudinal direction of the nonwoven fabric sheet of Example A is thinner than the low density portion DL. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The nonwoven fabric sheet of Example A has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorption and diffusion of excrement in absorbent articles equipped with the nonwoven fabric sheet of Example A and making it easier for wearers and others to recognize that the absorbent article has improved absorption and diffusion properties.

[0122] Example B The high density portion DH of the nonwoven fabric sheet of Example B was formed by conveying the sheet while being sandwiched between a sonic embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results for the nonwoven fabric sheet of Example B are as follows. Low density part DL thickness: 1.44 mm Fiber distance in low density section DL: 50.1 μm Thickness of high density part DH: 0.15 mm Distance between fibers in high density section DH: 16.2 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 3.1 <Horse blood drop test> Longitudinal length LK1 of the diffusion area K1 in the high density part DH: 57 mm The longitudinal length LK2 of the diffusion region K2 of the low-density part DL: 25 mm LK1 / LK2:2.28 <Water retention test> Weight before absorption: 0.484g Weight after absorption: 4.927g Holding weight: 4.443g Water retention rate: 9.18 It is clear that the thickness of the high density portion DH along the longitudinal direction of the nonwoven fabric sheet of Example B is thinner than the low density portion DL. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is greater than 3.0. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The water retention rate in the water retention test is 8 or more. The nonwoven fabric sheet of Example B has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorption and diffusion of excrement in an absorbent article equipped with the nonwoven fabric sheet of Example B and making it easier for the wearer to recognize that the absorbent article has improved absorption and diffusion properties. Furthermore, since the value obtained by dividing the inter-fiber distance in the low-density section DL by the inter-fiber distance in the high-density section DH is greater than 3.0, the absorbency of excretory liquid within the nonwoven fabric sheet of Example B can be improved, and an absorbent article equipped with the nonwoven fabric sheet of Example B has improved absorbency and diffusion properties, making it easier to give the impression to the wearer that the absorbent article has improved absorbency and diffusion properties. Furthermore, since the water retention rate in the water retention test was 8 or more, the nonwoven fabric sheet of Example B was able to retain a large amount of excrement, thereby reducing the risk of excrement leaking from absorbent articles using this nonwoven fabric sheet.

[0123] Example C The high density portion DH of the nonwoven fabric sheet of Example C was formed by conveying the sheet while being sandwiched between a heat embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results for the nonwoven fabric sheet of Example C are as follows. Low density part DL thickness: 1.46 mm Fiber distance in low density section DL: 50.5 μm Thickness of high density part DH: 0.09 mm Distance between fibers in high density section DH: 12.5 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 4.0 <Horse blood drop test> Longitudinal length LK1 of the diffusion area K1 in the high density part DH: 83 mm Longitudinal length LK2 of the diffusion region K2 of the low-density part DL: 30 mm LK1 / LK2:2.77 <Water retention test> Weight before absorption: 0.518g Weight after absorption: 4.947g Holding weight: 4.429g Water retention rate: 8.55 It is clear that the thickness of the high density portion DH along the longitudinal direction of the nonwoven fabric sheet of Example C is thinner than the low density portion DL. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is greater than 3.0. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The water retention rate in the water retention test is 8 or more. The nonwoven fabric sheet of Example C has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorption and diffusion of excrement in an absorbent article equipped with the nonwoven fabric sheet of Example C and making it easier for the wearer to recognize that the absorbent article has improved absorption and diffusion properties. Furthermore, since the value obtained by dividing the inter-fiber distance in the low-density portion DL by the inter-fiber distance in the high-density portion DH is greater than 3.0, the absorbency of excretory liquid within the nonwoven fabric sheet of Example C can be improved, and an absorbent article equipped with the nonwoven fabric sheet of Example C has improved absorbency and diffusion properties, making it easier to give the impression to the wearer that the absorbent article has improved absorbency and diffusion properties. Furthermore, the nonwoven fabric sheet of Example C can retain a large amount of excrement due to its water retention rate of 8 or more in the water retention test, thereby reducing the risk of excrement leaking from absorbent articles using this nonwoven fabric sheet.

[0124] Example D The high density portion DH of the nonwoven fabric sheet of Example D was formed by conveying the sheet while being sandwiched between a heat embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results for the nonwoven fabric sheet of Example D are as follows. Low density part DL thickness: 1.41 mm Fiber distance in low density section DL: 49.6 μm Thickness of high density part DH: 0.08 mm Distance between fibers in high density section DH: 11.8 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 4.2 <Horse blood drop test> Longitudinal length LK1 of the diffusion area K1 in the high density part DH: 78 mm The longitudinal length LK2 of the diffusion region K2 in the low-density part DL: 36.5 mm LK1 / LK2:2.14 <Water retention test> Weight before absorption: 0.496g Weight after absorption: 4.63g Holding weight: 4.134g Water retention rate: 8.33 It is clear that the nonwoven fabric sheet of Example D has a thinner thickness in the longitudinal direction of the high density portion DH than the low density portion DL. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is greater than 3.0. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The water retention rate in the water retention test is 8 or more. The nonwoven fabric sheet of Example D has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorbency and diffusion of excrement in an absorbent article equipped with the nonwoven fabric sheet of Example D and making it easier for the wearer to recognize that the absorbent article has improved absorbency and diffusion. Furthermore, since the value obtained by dividing the inter-fiber distance in the low-density section DL by the inter-fiber distance in the high-density section DH is greater than 3.0, the absorbency of excretory liquid within the nonwoven fabric sheet of Example D can be improved, and an absorbent article equipped with the nonwoven fabric sheet of Example D has improved absorbency and diffusion properties, making it easier to give the impression to the wearer that the absorbent article has improved absorbency and diffusion properties. Furthermore, the nonwoven fabric sheet of Example D can retain a large amount of excrement because the water retention rate in the water retention test was 8 or more, which reduces the risk of excrement leaking from absorbent articles using this nonwoven fabric sheet.

[0125] Example E The high density portion DH of the nonwoven fabric sheet of Example E was formed by conveying the sheet while being sandwiched between a sonic embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results for the nonwoven fabric sheet of Example E are as follows. Low density DL thickness: 1.29 mm Fiber distance in low density section DL: 47.5 μm Thickness of high density part DH: 0.08 mm Distance between fibers in high density section DH: 11.8 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 4.0 <Horse blood drop test> Length LK1 of the diffusion area K1 in the high density area DH in the longitudinal direction: 67.5 mm The longitudinal length LK2 of the diffusion region K2 of the low-density part DL: 26.5 mm LK1 / LK2:2.55 <Water retention test> Weight before absorption: 0.493g Weight after absorption: 4.621g Holding weight: 4.128g Water retention rate: 8.37 It is clear that the thickness of the high density portion DH along the longitudinal direction of the nonwoven fabric sheet of Example E is thinner than the low density portion DL. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is greater than 3.0. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The water retention rate in the water retention test is 8 or more. The nonwoven fabric sheet of Example E has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorbency and diffusion of excrement in an absorbent article equipped with the nonwoven fabric sheet of Example E and making it easier for the wearer to recognize that the absorbent article has improved absorbency and diffusion. Furthermore, since the value obtained by dividing the inter-fiber distance in the low-density section DL by the inter-fiber distance in the high-density section DH is greater than 3.0, the absorbency of excretory liquid within the nonwoven fabric sheet of Example E can be improved, and an absorbent article equipped with the nonwoven fabric sheet of Example E has improved absorbency and diffusion properties, making it easier to give the impression to the wearer that the absorbent article has improved absorbency and diffusion properties. Furthermore, since the water retention rate in the water retention test was 8 or more, the nonwoven fabric sheet of Example E was able to retain a large amount of excrement, thereby reducing the risk of excrement leaking from absorbent articles using this nonwoven fabric sheet.

[0126] Example F The high density portion DH of the nonwoven fabric sheet of Example F was formed by conveying the sheet while being sandwiched between a sonic embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results for the nonwoven fabric sheet of Example F are as follows. Low density part DL thickness: 1.71 mm Fiber distance in low density section DL: 54.6 μm Thickness of high density part DH: 0.04 mm Fiber spacing in high density section DH: 8.4 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 6.5 <Horse blood drop test> Longitudinal length LK1 of the diffusion area K1 in the high density part DH: 63 mm Longitudinal length LK2 of the diffusion area K2 of the low-density part DL: 39 mm LK1 / LK2:1.62 <Water retention test> Weight before absorption: 0.539g Weight after absorption: 4.917g Holding weight: 4.378g Water retention rate: 8.12 It is clear that the thickness of the high density portion DH along the longitudinal direction of the nonwoven fabric sheet of Example F is thinner than the low density portion DL. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is greater than 3.0. It is clear that the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high density area DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low density area DL in the horse blood drop test is 1.5 or more. The water retention rate in the water retention test is 8 or more. The nonwoven fabric sheet of Example F has a value of 1.5 or more obtained by dividing the longitudinal length LK1 of the horse blood diffusion area K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion area K2 in the low-density section DL, thereby improving the absorption and diffusion of excrement in an absorbent article equipped with the nonwoven fabric sheet of Example F and making it easier for the wearer to recognize that the absorbent article has improved absorption and diffusion properties. Furthermore, since the value obtained by dividing the inter-fiber distance in the low-density section DL by the inter-fiber distance in the high-density section DH is greater than 3.0, the absorbency of excretory liquid within the nonwoven fabric sheet of Example F can be improved, and an absorbent article equipped with the nonwoven fabric sheet of Example F has improved absorbency and diffusion properties, making it easier to give the impression to the wearer that the absorbent article has improved absorbency and diffusion properties. Furthermore, the nonwoven fabric sheet of Example F can retain a large amount of excrement due to the water retention rate of 8 or more in the water retention test, which reduces the risk of excrement leaking from absorbent articles using this nonwoven fabric sheet.

[0127] (Comparative Example 1) The nonwoven fabric sheet of Comparative Example 1 does not have a high density portion DH. That is, the nonwoven fabric sheet of Comparative Example 1 has the thickness and fiber density of the low density portion DL throughout its entire area, and the thickness and fiber density of this nonwoven fabric sheet are approximately constant throughout its entire area. The measurement results for the nonwoven fabric sheet of Example F are as follows: In Example F, the high density portion DH is not provided, and therefore the measurement results are for the low density portion DL only. Thickness of low density portion DL (thickness of nonwoven fabric sheet of Example F): 2.0 mm Fiber distance in low density section DL: 59.1 μm <Water retention test> Weight before absorption: 0.633g Weight after absorption: 6.84g Holding weight: 6.207g Water retention rate: 9.81

[0128] (Comparative Example 2) The high density portion DH of the nonwoven fabric sheet of Comparative Example 2 was formed by conveying the sheet while being sandwiched between a sonic embossing roll having protrusions on its outer peripheral surface and an anvil roll having a smooth outer peripheral surface. The measurement results of the nonwoven fabric sheet of Comparative Example 2 are as follows. Low density part DL thickness: 1.43 mm Fiber distance in low density section DL: 50 μm Thickness of high density part DH: 0.3 mm Distance between fibers in high density section DH: 22.9 μm Fiber distance in low density section DL / Fiber distance in high density section DH: 2.2 <Horse blood drop test> Longitudinal length LK1 of the diffusion area K1 in the high density part DH: 23 mm The longitudinal length LK2 of the diffusion region K2 of the low-density part DL: 23 mm LK1 / LK2:1.00 <Water retention test> Weight before absorption: 0.519g Weight after absorption: 5.243g Holding weight: 4.724g Water retention rate: 9.10 In the nonwoven fabric sheet of Comparative Example 2, the thickness of the high density portion DH along the longitudinal direction is thinner than the low density portion DL, but the difference in thickness between the high density portion DH and the low density portion DL is smaller than in Examples A to F described above. Moreover, the value obtained by dividing the inter-fiber distance in the low density portion DL by the inter-fiber distance in the high density portion DH is smaller than 3.0. In the horse blood drop test of the nonwoven fabric sheet of Comparative Example 2, the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density section DH was the same as the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density section DL. Therefore, the value obtained by dividing the longitudinal length LK1 of the horse blood diffusion region K1 in the high-density section DH by the longitudinal length LK2 of the horse blood diffusion region K2 in the low-density section DL was 1.00, and it is clear that the value obtained by dividing LK1 by LK2 was less than 1.5. In other words, in the nonwoven fabric sheet of Comparative Example 2, horse blood dropped onto the nonwoven fabric sheet of Comparative Example 2 diffuses equally in both the longitudinal and width directions. Therefore, when the nonwoven fabric sheet of Comparative Example 2 is used in an absorbent article such as napkin 1, diffusion in the longitudinal and width directions proceeds in the same manner. Therefore, if the diffusion area in the absorbent article is expanded, the diffusion of excrement in the width direction also expands, making it more likely that excrement will leak outward in the width direction of the absorbent article. This results in a decrease in the absorbency and diffusion properties of the absorbent article.

[0129] ===Other embodiments=== The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0130] In the above-described embodiment, the skin side layer 2 and the non-skin side layer 3 are nonwoven fabric sheets formed of latently crimped fibers 2f and 3f, respectively, and used as absorbents, but this is not limiting. The skin side layer 2 may be disposed as a top sheet instead of an absorbent, and a flexible sheet such as an air-through nonwoven fabric, a spunbond nonwoven fabric, or an SMS nonwoven fabric (spunbond-meltblown-spunbond nonwoven fabric) may be used. [Explanation of symbols]

[0131] 1. Napkins (sanitary napkins, absorbent articles), 1w wing part, 2 Skin side layer (skin side sheet), 2f latent crimp fiber (fiber), 3. Non-skin side layer (non-woven fabric sheet), 31 anterior region, 32 central area, 33 Posterior area, 3f latent crimp fiber (fiber), 4. Back sheet (non-skin side sheet), 5 side seats, 10 absorbent layer, 20 compression section, DH high density area (first area), DL Low density part (2nd area)

Claims

1. A nonwoven fabric sheet for use in an absorbent article, having a longitudinal direction, a transverse direction, and a thickness direction which intersect with each other, having a plurality of fibers, When viewed in the thickness direction, the film has a first region and a second region, the first region is a linear region extending in the vertical direction, has a higher fiber density than the second region, and is thinner than the second region; The first region and the second region are provided so that 5 minutes after 0.5 ml of horse blood is dropped onto the center of the nonwoven fabric sheet, the value obtained by dividing the length of the horse blood diffusion region in the first region in the vertical direction by the length of the horse blood diffusion region in the second region in the vertical direction is 1.5 or more. A nonwoven fabric sheet characterized by:

2. The nonwoven fabric sheet according to claim 1, The nonwoven fabric sheet is characterized in that the plurality of fibers are not fused to each other.

3. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet is characterized in that the plurality of fibers include latent crimp fibers.

4. The nonwoven fabric sheet according to claim 3, The nonwoven fabric sheet is characterized in that the latent crimped fiber is a composite fiber in which polyethylene terephthalate and modified polyethylene terephthalate are bonded side-by-side.

5. The nonwoven fabric sheet according to claim 1 or 2, A nonwoven fabric sheet, characterized in that a value obtained by dividing an average distance between fibers in the second region by an average distance between fibers in the first region is 3.0 or more.

6. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet is characterized in that it is an absorbent that absorbs liquid.

7. The nonwoven fabric sheet according to claim 1 or 2, The length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the transverse direction, A nonwoven fabric sheet, characterized in that the second regions are adjacent to both sides of the first region in the longitudinal direction.

8. The nonwoven fabric sheet according to claim 1 or 2, The length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the transverse direction, the first region is inclined with respect to the longitudinal direction, A nonwoven fabric sheet comprising a portion in which the smaller angle between the longitudinal direction and the first region is 45 degrees or less.

9. The nonwoven fabric sheet according to claim 1 or 2, The length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the transverse direction, A plurality of the first regions are provided, The nonwoven fabric sheet, wherein the plurality of first regions are spaced apart from one another in the lateral direction.

10. The nonwoven fabric sheet according to claim 1 or 2, The length of the nonwoven fabric sheet in the longitudinal direction is longer than the length of the nonwoven fabric sheet in the transverse direction, When the length of the nonwoven fabric sheet in the longitudinal direction is divided into three equal parts and the central part in the longitudinal direction is defined as the central part, The nonwoven fabric sheet, wherein the first region has at least a portion that is continuous from the upper end to the lower end of the central portion.

11. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet is characterized in that the average distance between the fibers is 11 to 28 μm.

12. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet, wherein the first region has a recess with a bottom.

13. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet, wherein the basis weight of the fibers of the nonwoven fabric sheet is 80 gsm or more and 140 gsm or less.

14. The nonwoven fabric sheet according to claim 1 or 2, The nonwoven fabric sheet is disposed between the wearer's crotch when the absorbent article is worn.

15. The nonwoven fabric sheet according to claim 1 or 2, The weight of the nonwoven fabric sheet before absorbing the liquid is defined as the pre-absorption weight, The weight of the nonwoven fabric sheet after immersing it in distilled water for 60 seconds and then removing it from the distilled water and hanging it for 90 seconds is defined as the weight after absorption. When the value obtained by subtracting the weight after absorption from the weight before absorption is defined as the weight of distilled water retained by the nonwoven fabric sheet, A nonwoven fabric sheet characterized in that a value obtained by dividing the retained weight by the weight before absorption is 8 or more.

16. The nonwoven fabric sheet according to claim 3, A nonwoven fabric sheet comprising at least one latent crimped fiber whose winding direction is inclined at an angle θ of more than 55 degrees relative to the axial direction.

17. An absorbent article comprising the nonwoven fabric sheet according to claim 1 or 2, a liquid-impermeable non-skin-side sheet provided on the non-skin side of the nonwoven fabric sheet; The nonwoven fabric sheet has a portion that contacts the non-skin-side sheet.

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