Non-woven fabric sheet and absorbent article

Abstract

A non-woven fabric sheet (3) for use in an absorbent article (1), the non-woven fabric sheet (3) having a plurality of fibers (3f) provided with potentially crimped fibers, and having a linear high-density section (DH) in which the density of the fibers (3f) is higher than that of the surroundings, the thickness of the high-density section (DH) being thinner than that of the surroundings, and the plurality of fibers (3f) being not welded to each other.

Description

Technical Field

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

[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 surface sheet disposed on the skin contact surface side, a back sheet disposed on the non-skin contact surface side, and an absorbent body disposed between the surface sheet and the back sheet. The absorbent body of Patent Document 1 is formed of pulp fibers or the like.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-176412 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the worn state of absorbent articles such as sanitary napkins in Patent Document 1, there are concerns that when excrement stays on the skin side of the surface sheet, the excrement will continuously contact the skin of the wearer, causing discomfort to the wearer, becoming a cause of skin roughness, or the excrement will leak from the absorbent article. Therefore, an absorbent article is desired that can quickly diffuse excrement absorbed from the surface sheet side into the absorbent body and can diffuse and be retained in the absorbent body.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a nonwoven fabric sheet for an absorbent article that facilitates diffusion of absorbed liquid in the nonwoven fabric sheet.

[0009] Means for Solving the Problems

[0010] The main invention for achieving the above object is a nonwoven fabric sheet for an absorbent article, characterized in that the nonwoven fabric sheet has a plurality of fibers including latent crimp fibers, and has a linear high-density portion where the density of the fibers is higher than that of the surroundings, the thickness of the high-density portion is thinner than that of the surroundings, and the plurality of fibers are not fused to each other.

[0011] Other features of the present invention will be clarified by the description in this specification and the drawings.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide a nonwoven fabric sheet for an absorbent article that facilitates diffusion of absorbed liquid in the nonwoven fabric sheet. Brief Description of the Drawings

[0014] Figure 1 It is a top view obtained by observing the sanitary napkin 1 from the skin side.

[0015] Figure 2 is Figure 1 a schematic cross-sectional view taken along the line A-A in

[0016] Figure 3 a view for explaining the structure of the sanitary napkin 1.

[0017] Figure 4 a view for explaining the absorbent layer 10 of the sanitary napkin 1.

[0018] Figure 5 A is a view schematically showing a cross-section of the skin-side layer 2. Figure 5 B is a view schematically showing a cross-section of the non-skin-side layer 3.

[0019] Figure 6 is Figure 4 an enlarged view of a part X in

[0020] Figure 7 is Figure 6 a schematic cross-sectional view taken along the line B-B in Detailed implementation mode

[0021] According to the description in this specification and the drawings, at least the following matters become clear.

[0022] (Solution 1)

[0023] A non-woven fabric sheet for absorbent articles, characterized in that the non-woven fabric sheet has a plurality of fibers having latent crimped fibers, and has a linear high-density portion where the density of the fibers is higher than that of the surroundings, the thickness of the high-density portion is thinner than that of the surroundings, and the plurality of fibers are not fused to each other.

[0024] Parts where the fibers are fused tend to impede the diffusion of liquid. On the other hand, the narrower the gap between the fibers, the easier it is for the liquid to diffuse by capillary action. In the non-woven fabric sheet according to Solution 1, compared with the case where the fibers are fused, by not fusing the fibers, the concern of impeding the diffusion of the absorbed liquid can be reduced, and the concern that the latent crimped fibers such as pulp fibers absorb liquid and swell can be reduced, so it is easy to maintain the gap between the fibers. In addition, for the non-woven fabric sheet, on the basis of using the crimping of the latent crimped fibers to narrow the gap between the fibers, by having a high-density portion to further narrow the gap between the fibers, it is thus possible to easily diffuse the absorbed liquid in the non-woven fabric sheet by capillary action.

[0025] (Solution 2)

[0026] According to the non-woven fabric sheet described in Solution 1, the non-woven fabric sheet is a liquid-absorbing absorber.

[0027] According to the non-woven fabric sheet of Solution 2, since it is easy to make the absorbed liquid diffuse within the non-woven fabric sheet, it is possible to reduce the situation where the absorbed excrement stays locally, and it is possible to reduce the leakage of excrement and the discomfort brought to the wearer.

[0028] (Solution 3)

[0029] According to the non-woven fabric sheet described in Solution 1 or 2, the non-woven fabric sheet has a length direction, a width direction, and a thickness direction. The length in the length direction of the non-woven fabric sheet is longer than the length in the width direction. The periphery of the high-density part is a low-density part where the density of the fibers is lower than that of the high-density part, and the low-density parts are adjacent to both sides in the length direction of the high-density part.

[0030] According to the non-woven fabric sheet of Solution 3, it is easy to transfer the liquid absorbed by the low-density part on one side in the length direction to the high-density part by capillary action, and use the low-density part located on the other side in the length direction to absorb the liquid that has been absorbed by the high-density part but not completely absorbed. Thus, it is easy to promote the diffusion of the liquid in the length direction of the non-woven fabric sheet.

[0031] (Solution 4)

[0032] According to the non-woven fabric sheet described in any one of Solutions 1 to 3, the non-woven fabric sheet has a length direction, a width direction, and a thickness direction. The length in the length direction of the non-woven fabric sheet is longer than the length in the width direction. For the high-density part, it is inclined with respect to the length direction, and has a part where the smaller angle among the angles formed by the length direction and the high-density part is 45 degrees or less.

[0033] According to the non-woven fabric sheet of Solution 4, it is easy to make the absorbed liquid diffuse along the length direction in the length direction of the non-woven fabric sheet.

[0034] (Solution 5)

[0035] According to the non-woven fabric sheet described in any one of Solutions 1 to 4, the non-woven fabric sheet has a length direction, a width direction, and a thickness direction. The length in the length direction of the non-woven fabric sheet is longer than the length in the width direction. When the length in the length direction of the non-woven fabric sheet is divided into three equal parts and the central part in the length direction is set as the central area, the high-density part has at least a part that is continuous from the upper end to the lower end of the central area.

[0036] According to the non-woven fabric sheet of Solution 5, it is easy to promote the diffusion of the liquid in the length direction in the central area.

[0037] (Solution 6)

[0038] For the non-woven fabric sheet described in any one of Schemes 1 to 5, the average value of the distance between the fibers is 5 μm or more and 30 μm or less.

[0039] For the non-woven fabric sheet of Scheme 6, it is easy to prevent the situation where the diffusion of the liquid is hindered due to the fusion of the fibers, and compared with the case where the average value of the distance between the fibers is less than 5 μm, it is easy to ensure the flow path for diffusing the liquid and the region for holding the liquid, and compared with the case where the average value of the distance between the fibers is greater than 30 μm, it is easy to promote the introduction and absorption of the absorbed liquid by capillary action.

[0040] (Scheme 7)

[0041] For the non-woven fabric sheet described in any one of Schemes 1 to 6, a bottomed concave portion is formed in the high-density portion.

[0042] For the non-woven fabric sheet of Scheme 7, even when a bottomed concave portion is formed, it is easy to diffuse the absorbed liquid in the non-woven fabric sheet.

[0043] (Scheme 8)

[0044] For the non-woven fabric sheet described in any one of Schemes 1 to 7, the weight per unit area of the fibers of the non-woven fabric sheet is 80 gsm or more and 350 gsm or less.

[0045] For the non-woven fabric sheet of Scheme 8, compared with the case where the weight per unit area of the fibers of the non-woven fabric sheet is less than 80 gsm, the non-woven fabric sheet is easy to absorb liquid, and compared with the case where the weight per unit area of the fibers of the non-woven fabric sheet is greater than 350 gsm, the concern that the non-woven fabric sheet becomes too thick or too hard can be reduced.

[0046] (Scheme 9)

[0047] For the non-woven fabric sheet described in any one of Schemes 1 to 8, the non-woven fabric sheet is for an absorbent article, and the non-woven fabric sheet is provided at the crotch position of the wearer in the wearing state of the absorbent article.

[0048] For the non-woven fabric sheet of Scheme 9, when the non-woven fabric sheet absorbs excrement, it is easy to diffuse the excrement in the non-woven fabric sheet, and the discomfort caused by excrement leakage or local retention of excrement can be reduced.

[0049] (Scheme 10)

[0050] The nonwoven fabric sheet according to any one of Aspects 1 to 9, an absorbent article, the absorbent article having a thickness direction, and a skin-side sheet provided at a position closer to the skin than the nonwoven fabric sheet, the skin-side sheet having a first void formed by a plurality of fibers, the nonwoven fabric sheet having a second void formed by the plurality of fibers, the ratio of the second void of the nonwoven fabric sheet in a void ratio evaluation test for quantitatively evaluating the ratio of the voids in a predetermined region being smaller than the ratio of the first void of the skin-side sheet in the void ratio evaluation test.

[0051] The nonwoven fabric sheet according to Aspect 10 is such that it is easy to cause the liquid absorbed by the skin-side sheet to diffuse to the nonwoven fabric sheet by capillary action, so it is easy to reduce the liquid remaining on the skin-side sheet, and it is possible to reduce the discomfort caused by the excrement coming into contact with the wearer's skin.

[0052] (Aspect 11)

[0053] The nonwoven fabric sheet according to any one of Aspects 1 to 10, an absorbent article, the absorbent article having a length direction, a width direction, and a thickness direction, the length of the nonwoven fabric sheet in the length direction being longer than the length in the width direction, the absorbent article having a skin-side sheet provided at a position closer to the skin than the nonwoven fabric sheet, and no adhesive being provided between the nonwoven fabric sheet and the skin-side sheet at the central portion in the width direction.

[0054] The nonwoven fabric sheet according to Aspect 11 can reduce the concern that the adhesive hinders the absorption of liquid.

[0055] ===Embodiment===

[0056] As the absorbent article of the present invention, the physiological sanitary napkin 1 (hereinafter also referred to as "sanitary napkin 1") will be taken as an example to illustrate the embodiment. However, the absorbent article of the present invention can also be an adult or infant panty-type disposable diaper, a belt-type disposable diaper, a physiological short, a physiological sanitary napkin, a light incontinence pad, an absorbent pad, an animal disposable diaper, an absorbent sheet, a fresh water absorbent pad (Japanese: ドリップシート), etc. In addition, in the case of a fresh water absorbent pad, etc., the "wearing state" in the following embodiment becomes the "using state", and the wearer becomes the "user, etc.". Hereinafter, the wearing state will also be referred to as the "using state", and the wearer will also be referred to as the "user, etc.".

[0057] <<<Structure of the physiological sanitary napkin 1>>>

[0058] Figure 1 is a top view obtained by observing the physiological sanitary napkin 1 (hereinafter also referred to as "sanitary napkin") from the skin side. Figure 2 is a schematic cross-sectional view taken along the line A-A of the sanitary napkin 1. Figure 3This is a diagram showing the structure of the sanitary napkin 1. The sanitary napkin 1 has a length direction, a width direction, and a thickness direction that are orthogonal to each other. The side that abuts against the wearer's skin in the thickness direction 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) in the worn state, and is also referred to as the "absorbing surface side". The non-skin side in the thickness direction is the opposite side of the absorbing surface side, and is also referred to as the "non-absorbing surface side". Figure 1 As shown in etc., the center line C-C represents the center (central position) in the width direction of the sanitary napkin 1.

[0059] The sanitary napkin 1 has a skin side layer (non-woven fabric sheet) 2, a non-skin side layer (non-woven fabric sheet) 3, a bottom sheet 4, and side sheets 5. As Figure 3 shown in etc., the sanitary napkin 1 sequentially overlaps the side sheets 5, the skin side layer 2, the non-skin side layer 3, and the bottom sheet 4 in order from the skin side in the thickness direction. Each member overlapped in the thickness direction is fixed to each other using an adhesive such as a hot melt adhesive.

[0060] The skin side layer 2 is a skin side sheet located at the most skin-side position in the central part of the width direction of the sanitary napkin 1, and is an absorption member that abuts against the excretory opening and receives excrement discharged from the excretory opening in the worn state. The skin side layer 2 is a substantially rectangular shape that is longer in the length direction, and the length L2 in the length direction is longer than the length W2 in the width direction. By disposing the skin side layer 2 at the crotch position of the wearer in the worn state of the sanitary napkin 1, when the sanitary napkin 1 absorbs excrement, the skin side layer 2 can absorb the excrement and cause the absorbed excrement to diffuse toward the non-skin side layer 3. Therefore, it is possible to reduce the discomfort to the wearer caused by leakage of excrement from the sanitary napkin 1 or local retention of excrement on the surface of the skin side layer 2 or the like.

[0061] The non-skin side layer 3 is a non-skin side sheet provided between the skin side layer 2 and the bottom sheet 4 in the thickness direction, and the non-skin side layer 3 is smaller in size than the skin side layer 2 in a top view. The non-skin side layer 3 is a substantially rectangular shape that is longer in the length direction, and the length L3 in the length direction is longer than the length W3 in the width direction. The non-skin side layer 3 is an absorption member that absorbs and holds the excrement absorbed by the skin side layer 2. By disposing the non-skin side layer 3 at the crotch position of the wearer in the worn state of the sanitary napkin 1, when the sanitary napkin 1 absorbs excrement, the non-skin side layer 3 can absorb the excrement and cause the excrement to diffuse within the non-skin side layer 3. Therefore, it is possible to reduce the discomfort to the wearer caused by leakage of excrement from the sanitary napkin 1 or local retention of excrement on the surface of the skin side layer 2 or the like.

[0062] The skin side layer 2 and the non-skin side layer 3 are respectively made of latent crimped fibers 2f and latent crimped fibers 3f (refer to Figure 5A non-woven fabric (non-woven fabric sheet) thus formed. The skin-side layer 2 and the non-skin-side layer 3 of the present embodiment are non-woven fabrics formed only of latent crimp fibers (100% latent crimp fibers). However, for the layers (non-woven fabrics) constituting the skin-side layer 2 and the non-skin-side layer 3, in addition to using latent crimp fibers, fibers made of polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters (PET, PBT), polyamides, and their composite fibers can also be used. In addition, hydrophilic fibers such as rayon, pulp, and cotton can also be used. Hereinafter, the latent crimp fiber 2f will also be simply referred to as "fiber 2f", and the latent crimp fiber 3f will be simply referred to as "fiber 3f".

[0063] "Non-woven fabric" refers to a fabric formed as follows: in a fiber sheet, mesh, or mat, the fibers are oriented in one direction or randomly, and the fibers are joined together by interlacing, and / or fusing, and / or bonding (JIS L0222:2001 Non-woven fabric terminology 101). That is, a non-woven fabric is a fabric that is integrated without weaving fibers and is a sheet material having a breaking strength of 5 [N] / 25 mm or more. The breaking strength can be measured by a known method. For example, it can be measured by the following method. Use a tensile testing machine (manufactured by Shimadzu Corporation: AUTOGRAPH, AGS-1kNG) equipped with a load cell with a maximum load capacity of 50 N. When measuring the separation strength of a non-woven fabric sheet, hold the front end of one side in the long side direction or short side direction of the non-woven fabric sheet with one chuck, and hold the other side of the non-woven fabric sheet with the other chuck. Using the tensile testing machine, stretch the two chucks at a constant speed (example: 100 mm / min) in such a way that the distance between the two chucks increases, and measure the load applied to the two chucks. The load at the time when the non-woven fabric sheet breaks is defined as the breaking strength.

[0064] Examples of non-woven fabrics include: non-woven fabrics obtained by the meltblowing method (meltblown non-woven fabrics), non-woven fabrics obtained by the electrospinning method (electrospun non-woven fabrics), non-woven fabrics obtained by the spunbond method (spunbond non-woven fabrics), non-woven fabrics manufactured by the hot air method (hot air non-woven fabrics), non-woven fabrics manufactured by the hydroentangling method (hydroentangled non-woven fabrics), or non-woven fabrics manufactured by the needling method (needle-punched non-woven fabrics), or laminates of two or more of these non-woven fabrics, or laminates of these non-woven fabrics and non-woven fabrics other than these non-woven fabrics, other materials, etc. The skin-side layer 2 and the non-skin-side layer 3 of the present embodiment are each a hydroentangled non-woven fabric formed by interlacing fibers with each other using water flow without using an adhesive.

[0065] The non-woven fabric sheet of the skin-side layer 2 of the sanitary napkin 1 of the present embodiment is formed by the following hydroentangling method.

[0066] (a) First, the hydrophilic fiber 2fb is processed using a carding machine or the like to form a non-skin-side fiber web having a form such as a carded web.

[0067] (b) Next, while conveying the non-skin-side fiber web, a skin-side fiber web having a form such as a carded web, which is obtained by processing the hydrophobic fiber 2fa using a carding machine or the like, is supplied onto and laminated on the non-skin-side fiber web to obtain a laminated web.

[0068] (c) By performing high-pressure water flow treatment such as water jet from the skin side of the laminated web, the fibers between the respective fiber layers and the fibers of each web are intertwined with each other to obtain a laminate.

[0069] (d) Finally, the laminate is put into a dryer and heated to a temperature at which the latent shrinkable fibers can shrink, whereby an integrated non-woven fabric sheet (skin-side layer 2) is obtained. This non-woven fabric sheet has voids formed by a plurality of fibers 2f.

[0070] The non-woven fabric sheet of the non-skin-side layer 3 of the sanitary napkin 1 of the present embodiment is also formed by the same method as the non-woven fabric sheet of the skin-side layer 2. However, the non-woven fabric sheet of the non-skin-side layer 3 is different from the skin-side layer 2 in that instead of using hydrophobic fibers, only a web of hydrophilic fibers is laminated.

[0071] The latent shrinkable fibers 2f, 3f are fibers that shrink by heat treatment and exhibit a spiral shape. Among the latent shrinkable fibers 2f, 3f, for example, there are side-by-side type composite fibers in which a high shrinkage component and a low shrinkage component are arranged side by side, and eccentric core-sheath type composite fibers in which the high shrinkage component is the core and the low shrinkage component is the sheath and the centers of gravity of the two components do not overlap at one point. When the latent shrinkable fibers are caused to shrink, the latent shrinkable fibers shrink in a coiled shape, for example.

[0072] As the plurality of resins having different thermal shrinkage rates or thermal expansion rates for forming the latent shrinkable fibers 2f, 3f, as long as they are a combination of resins having different thermal shrinkage rates or thermal expansion rates from each other, they are used without particular limitation, and may be a combination of the same type or single resin, or a combination of different types of resins. As a specific example of the combination of resins having different thermal shrinkage rates or thermal expansion rates for forming the latent shrinkable fibers, for example, latent shrinkable fibers that can adopt a combination of polyester resins with each other or a combination of polyamide resins with each other can be used.

[0073] The non-woven fabrics of the skin-side layer 2 and the non-skin-side layer 3 in this embodiment are a combination of polyester resins (single-component resins). Specifically, potential crimpable fibers of a combination of polyethylene terephthalate (PET) and modified PET are used. In addition, the modified PET is obtained by copolymerizing a glycol component other than ethylene glycol or a dicarboxylic acid component other than terephthalic acid as a minor component with ethylene glycol and terephthalic acid which are constituent components of PET for modification. Specific examples of the glycol component other than ethylene glycol include, for example, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene ether glycol, and the like. In addition, specific examples of the dicarboxylic acid component other than terephthalic acid include, for example, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, and the like. And a web formed of potential crimpable fibers of a combination of PET and modified PET is formed by a web forming unit such as a carding machine. The fibers of the web are interlaced with each other by the hydroentangling method to become a non-woven fabric state, and the web is heated to a predetermined temperature to cause the potential crimpable fibers to exhibit crimping. Thus, the non-woven fabrics of the skin-side layer 2 and the non-skin-side layer 3 are produced. As a result, the unit area weight of the potential crimped fibers of the heated non-woven fabric is larger than the unit area weight of the potential crimpable fibers in the non-woven fabric state before heating. That is to say, the non-woven fabric shrinks due to the crimping of the potential crimpable fibers, and the unit area weight of the fibers becomes larger.

[0074] The skin-side layer 2 and the non-skin-side layer 3 are each an absorbent layer 10 having a predetermined thickness, having liquid permeability, having a liquid absorption function, and having a liquid retention function. Figure 4 This is a diagram for explaining the absorbent layer 10 of the sanitary napkin 1. In the sanitary napkin 1, the skin-side layer 2 is a skin-side sheet that abuts against the skin of the wearer. It is a member that first bears excrement in the wearing state and is a member that absorbs the excrement received in the skin-side layer 2 and allows the excrement to pass through toward the non-skin side. The non-skin-side layer 3 is a member that absorbs and retains the excrement that has passed through from the skin-side layer 2.

[0075] As Figure 5 shown, the skin-side layer 2 and the non-skin-side layer 3 each have voids formed by a plurality of fibers (potential crimped fibers) 2f, 3f. Figure 5 A is a diagram schematically showing a cross-section of the skin-side layer 2, Figure 5FIG. B schematically shows a cross-section of the non-skin side layer 3, and the dimensions etc. are not necessarily accurate. In addition, the voids in the skin side layer 2 and the non-skin side layer 3 may be voids between non-continuous (multiple fibers) fibers, or may be voids formed by a single continuous fiber being bent or helical, or may be voids formed by a combination of the above voids. The void formed by multiple fibers 2f, 3f refers to the space or region in the skin side layer 2 and the non-skin side layer 3 where multiple fibers 2f, 3f are not provided. In addition, the void is not only a space surrounded by fibers 2f, 3f or a space enclosed by fibers, but may also be a space where at least a part of the void formed by fibers 2f, 3f is open.

[0076] Since the skin side layer 2 and the non-skin side layer 3 respectively have latent crimped fibers 2f, 3f, they form a helical shape in such a way that the fibers 2f, 3f are intertwined with each other through the crimp of the fibers 2f, 3f. For example, the distance between the fibers 2f, 3f is shortened due to the crimp, or other fibers enter between the fibers 2f, 3f whose distance has been shortened, and the void between the fibers 2f, 3f becomes smaller. Therefore, the void formed by the fibers 2f, 3f containing latent crimped fibers is smaller than the void formed by multiple fibers in a normal non-woven fabric formed by non-crimped fibers.

[0077] In addition, for the latent crimped fibers 2f, 3f provided in the skin side layer 2 and the non-skin side layer 3 respectively, the fibers themselves are not easily absorbent. For example, in fibers such as pulp fibers, when they absorb liquid (excrement), the thickness of the fibers becomes thicker, but even when the latent crimped fibers 2f, 3f in the skin side layer 2 and the non-skin side layer 3 come into contact with liquid, the inside of the fibers is not easily absorbent. Therefore, in the skin side layer 2 and the non-skin side layer 3, in the wearing state, even when the sanitary napkin 1 absorbs excrement, for the latent crimped fibers 2f, 3f in the skin side layer 2 and the non-skin side layer 3, the thickness of the fibers themselves is not easily thickened. By the thickness of the fibers themselves not being easily thickened, the size of the void formed by the fibers 2f, 3f is not easily reduced, and the void is not easily flattened. Thus, in the skin side layer 2 and the non-skin side layer 3, liquid (excrement) can be retained in the void formed by the fibers 2f, 3f. Therefore, the skin side layer 2 and the non-skin side layer 3 are respectively layers that can allow liquid to pass through and are layers that can absorb and retain liquid. In addition, the skin side layer 2 and the non-skin side layer 3 are respectively non-woven fabric sheets formed by the fibers 2f, 3f, have voids formed by the fibers 2f, 3f, and thus have excellent air permeability, can reduce the sultriness and skin roughness brought to the wearer in the wearing state, and can improve the comfort of the wearing state.

[0078] As described above, the potential crimped fibers 2f in the skin-side layer 2 are potential crimped fibers that are a combination of PET and modified PET, and fibers of the same fineness are used throughout the area. In the present embodiment, the fineness of the potential crimped fiber 2fa is set to 2.2 dtex. In addition, the average narrow width of the voids in the skin-side layer 2 is 104 μm. Also, the proportion of voids in the skin-side layer 2 (the proportion of the area in the skin-side layer 2 where the fibers 2f are not provided) is 94%. The basis weight per unit area of the skin-side layer 2 is about 170 gsm. In addition, in the skin-side layer 2, preferably, hydrophobic fibers are used on the skin side and hydrophilic fibers are used on the non-skin side.

[0079] The potential crimped fibers 3f in the non-skin-side layer 3 are potential crimped fibers that are a combination of PET and modified PET, and fibers of the same fineness are used throughout the entire area in the thickness direction. The fineness of the potential crimped fiber 3f in the non-skin-side layer 3 of the present embodiment is set to 2.2 dtex.

[0080] The basis weight per unit area of the non-skin-side layer 3 of the present embodiment is about 120 gsm. Preferably, the basis weight per unit area of the fibers 3f in the non-skin-side layer 3 is 80 gsm or more and 200 gsm or less. Thus, compared with the case where the basis weight per unit area of the fibers 3f in the non-skin-side layer 3 is less than 80 gsm, more voids are formed in the non-skin-side layer 3, and thus it is easy to absorb liquid. On the other hand, compared with the case where the basis weight per unit area of the fibers 3f in the non-skin-side layer 3 is greater than 200 gsm, the concern that the non-skin-side layer 3 becomes too thick or too hard can be reduced.

[0081] The backsheet 4 is a liquid-impermeable sheet (outer layer) disposed on the non-skin side of the non-skin-side layer 3. As the liquid-impermeable sheet, a resin film of polyethylene (PE) or the like can be exemplified. The side sheets 5 are sheets extending outward from both side portions in the width direction of the skin side surface of the skin-side layer 2. As the side sheets 5, a hydrophobic thermal-bonded nonwoven fabric, a hydrophobic spunbond nonwoven fabric, or the like can be exemplified.

[0082] In addition, the sanitary napkin 1 has a pair of wings 1w extending outward in the width direction at a substantially central portion in the length direction. The wings 1w are formed by the side sheets 5 and the backsheet 4. In addition, it may be that the sanitary napkin 1 does not necessarily have the wings 1w. In the case where the sanitary napkin 1 does not have the wings 1w, the side sheets 5 may or may not be provided.

[0083] In addition, the sanitary napkin 1 has a compression portion 20 formed by the skin-side layer 2 and the non-skin-side layer 3 being recessed in the thickness direction. The compression portion 20 can be used to fix the positions of the skin-side layer 2 and the non-skin-side layer 3 or to improve the liquid diffusibility of the sanitary napkin 1.

[0084] In the compression part 20, the thickness of the sanitary napkin 1 is thinner compared to the surroundings, and the fiber density of the sanitary napkin 1 (skin-side layer 2 and non-skin-side layer 3) becomes higher. These comparisons are preferably made using known methods. As a comparison of the thickness of the sanitary napkin 1, methods such as visual comparison can be exemplified, or values measured by applying pressure to an object part, for example, using a dial thickness gauge ID-C1012C manufactured by Mitutoyo Corporation or an equivalent instrument, and then comparing them. As a comparison of the density of the sanitary napkin 1, a method of comparing based on an image obtained by magnifying a cross-section of the sanitary napkin 1 cut along the thickness direction using an electron microscope or the like can be exemplified. Additionally, the shape of the compression part 20 is not limited to the 2 shape shown. For example, it can also be a shape in which a plurality of dot-like compression parts are discretely arranged. Figure 1

[0085] <<<Regarding the non-skin-side layer 3>>>

[0086] The non-skin-side layer 3 is a non-woven fabric sheet for the sanitary napkin 1 (absorbent article). As described above, it has a plurality of fibers 3f having latent crimped fibers. The non-skin-side layer 3 has a linear high-density part DH where the density of the fibers 3f is higher than the surroundings (low-density part DL) and a low-density part DL where the density of the fibers 3f is lower than the high-density part DH. The thickness of the high-density part DH is thinner than the surroundings (low-density part DL), and the fibers are not fused to each other.

[0087] The "linear" high-density part DH is not limited to a part where the part with a density higher than the surroundings is linearly continuous. In the case where a plurality of parts with higher density are intermittently arranged linearly or dot-like, the high-density part DH is set to include the region between adjacent plurality of parts with higher density. The region between adjacent plurality of parts with higher density that are close to each other is a region where the fiber density is lower than that of the part formed as the part with higher density but higher than the surroundings. Therefore, as a whole, it becomes a linear high-density part.

[0088] For the high-density part DH of the sanitary napkin 1 of the present embodiment, a plurality of high-density parts DL that are continuous in the length direction from the upper end to the lower end of the non-skin-side layer 3 are arranged at a predetermined interval in the width direction. The high-density part DL that is continuous in the length direction has a wavy shape with concave and convex parts alternating on both sides in the width direction. Figure 6 is Figure 4 an enlarged view of part X in Figure 7 is Figure 6 a schematic cross-sectional view taken along the B-B direction in Figure 7 ​As shown, in the sanitary napkin 1 of the present embodiment, the length in the thickness direction of the low-density portion DL is the length H3 in the thickness direction of the non-skin side layer 3, and the length Hdh in the thickness direction of the high-density portion DH is shorter than the length H3 in the thickness direction of the low-density portion DL (Hdh < H3). The comparison of the thicknesses of the high-density portion DH and the low-density portion DL of the non-skin side layer 3 can be performed by a known method. For example, it can be measured by the above-described method.

[0089] The high-density portion DL can be formed, for example, by sandwiching a non-woven fabric sheet having a substantially uniform thickness in the thickness direction between a pair of rollers during the manufacturing process of the non-skin side layer 3 and conveying it. One of the pair of rollers is a hot embossing roller having convex portions on the outer peripheral surface, and the other roller is an anvil roller having a smooth outer peripheral surface. By making the heating temperature of the hot embossing roller for the fiber 3f higher than the softening point of the latent crimped fiber of the fiber 3f of the non-skin side layer 3 and lower than the melting point, the fiber 3f is not welded in the high-density portion DH, and it is easy to maintain the form in which the thickness of the high-density portion DH is thinner than the thickness of the low-density portion DL.

[0090] Generally, in a non-woven fabric sheet, the portion where the fibers are welded easily hinders the diffusion of excrement (liquid). On the other hand, the narrower the gap between the fibers, the easier it is for the excrement (liquid) to diffuse. Therefore, in the high-density portion DH, compared with the case where the fibers 3f are welded to each other, by not welding the fibers 3f to each other, the concern of hindering the diffusion of the absorbed liquid (excrement) can be reduced. In addition, since the non-skin side layer 3 is a non-woven fabric sheet having latent crimped fibers, a plurality of fibers are intertwined to maintain its shape, and thus it is easy to maintain the shape of the voids formed by the plurality of fibers. Also, it is easy to reduce the concern of flattening the voids formed by the fibers 3f by absorbing liquid and swelling like pulp fibers, and it is easy to maintain the voids. In addition, in the non-skin side layer 3, the latent crimped fibers 3f are crimped in a spiral (coiled) shape, and thus the interval between the fibers 3f is easily narrowed. Furthermore, by providing the high-density portion DH in the non-skin side layer 3, it is easier to provide a portion where the gap between the fibers 3f is narrow. Therefore, in the non-skin side layer 3 after absorbing the liquid (excrement), it is easy to maintain the voids between the fibers 3f, and it is easy to promote the introduction of the liquid into the high-density portion DH by the capillary action based on the high-density portion DH, and it is easy to diffuse the absorbed liquid within the non-skin side layer 3.

[0091] As Figure 7As shown, preferably, the high-density portion DH is formed with a bottomed concave portion. That is to say, preferably, a portion that is different from the voids formed by the fibers 3f with each other and that penetrates intentionally in the thickness direction is not provided in the high-density portion DH. Even when the high-density portion DH has a bottomed concave portion, it is easy to promote the diffusion of the liquid in the non-skin-side layer 3. In addition, in the case of a sanitary napkin 1 having a skin-side layer 2 at a position closer to the skin side than the non-skin-side layer 3 and the concave portion of the non-skin-side layer 3 being provided on the skin side, the concave portion of the high-density portion DH is likely to be separated from the skin-side layer 2. Therefore, the concern that the excrement temporarily absorbed by the non-skin-side layer 3 returns to the skin-side layer 2 can be reduced, and the discomfort caused to the wearer's skin can be reduced. In addition, in the non-skin-side layer 3 of the sanitary napkin 1, the skin side surface has a concave portion that is recessed toward the non-skin side, and the non-skin side surface has a flat surface, but it is not limited to this. Concave portions may be provided on both the skin side surface and the non-skin side surface of the non-skin-side layer 3. In addition, when viewed in the thickness direction, the concave portion on the skin side surface and the concave portion on the non-skin side surface may be provided at the same position or at different positions. Furthermore, it may be such a structure that the skin side surface of the non-skin-side layer 3 is a flat surface, and the non-skin side surface has a concave portion that is recessed toward the skin side.

[0092] The non-skin-side layer 3 is a non-woven fabric sheet, but in the sanitary napkin 1, the non-skin-side layer 3 is used as an absorber for absorbing liquid. By using the non-skin-side layer 3 as an absorber, it is easy to use the high-density portion DL to diffuse the absorbed excrement within the non-skin-side layer 3. Therefore, it is easy to reduce the situation where the absorbed excrement stays locally, and thus the concern that the excrement continuously contacts the wearer's skin or the excrement leaks from the sanitary napkin 1 before being absorbed into the inside of the sanitary napkin 1 can be reduced.

[0093] The absorber (absorbent core) of a general absorbent article is formed of liquid-absorbent fibers such as pulp fibers, SAP, a polymer foam structure, etc. For example, the absorber (absorbent core) formed of liquid-absorbent fibers such as pulp fibers is a simple laminate of liquid-absorbent fibers, and the fibers are not intertwined with each other such as intertwining the liquid-absorbent fibers with each other. Therefore, it is difficult to maintain the shape of the voids formed by the plurality of fibers as voids. When absorbing liquid, not only do the liquid-absorbent fibers themselves become thicker, but the shape of the voids also easily deforms. Therefore, it has the characteristic that it is difficult to absorb liquid in the voids. In addition, since the liquid-absorbent fibers themselves absorb liquid, the voids are easily flattened. In addition, the breaking strength of the absorbent core formed of liquid-absorbent fibers such as pulp fibers is less than 5 [N] / 25 mm, so it is more likely to deform and break compared to the non-woven fabric sheet. Thus, when the absorber formed of liquid-absorbent fibers absorbs liquid, the shape of the fibers easily deforms, so the absorber easily loses its elasticity and the strength also easily decreases.

[0094] In contrast, in the non-skin side layer 3 formed of a non-woven fabric sheet, a plurality of fibers are intertwined so as to maintain its shape, and thus it is easy to maintain the shape of the voids formed by the plurality of fibers, and thus it is easy to hold liquid in the voids. In addition, by using the intertwining to maintain the shape of the voids, even when the liquid is absorbed, the loss of elasticity of the shape of the non-skin side layer 3 (absorbent body) can be reduced, and it is easy to maintain the shape of the non-skin side layer 3. Therefore, even when the sanitary napkin 1 is worn for a long time or the excrement is absorbed multiple times, the deformation of the sanitary napkin 1 (non-skin side layer 3) can be reduced. Furthermore, the fibers 3f are not fused to each other and have voids formed by the fibers 3f, so the air permeability is also excellent compared to the absorbent body of a normal absorbent article.

[0095] And, in the non-skin side layer 3, preferably, low-density portions DL are respectively adjacent to both sides in the length direction of the high-density portion DH. For example, as Figure 6 shown, in the imaginary straight line L of the non-skin side layer 3, a plurality of high-density portions DH are intermittently arranged in the length direction. The imaginary straight line L is an imaginary straight line along the length direction and parallel to the length direction. And, low-density portions DL are respectively provided adjacent to the front side and the rear side in the length direction of one high-density portion DH.

[0096] The high-density portion DH of the non-skin side layer 3 is a portion where the density of the fibers 3f is relatively high, so the voids formed by the fibers 3f are relatively small, and thus it is easy to introduce liquid by capillary action. The high-density portion DH is a portion where it is easy to introduce liquid and on the other hand the voids are relatively small, so the liquid retention ability of holding liquid is relatively low. The low-density portion DL is a portion where the voids are larger than the voids of the high-density portion DH, so the introduction of liquid is weaker than that of the high-density portion DH, but since the voids are larger, the liquid retention ability of holding liquid is larger. Thus, by providing low-density portions DL on both sides in the length direction of the high-density portion DH of the non-skin side layer 3, it is easy to introduce the liquid temporarily absorbed (held) by the low-density portion DL to the high-density portion DH adjacent to the low-density portion DL on one side in the length direction, and the liquid introduced into the high-density portion DH and not completely held can diffuse to the low-density portion DL adjacent to the high-density portion DH on one side in the length direction. By performing the above process one or more times, it is easy to promote the diffusion of the liquid in the length direction.

[0097] In addition, preferably, for the linear high-density portion DH, it is inclined with respect to the length direction, and a portion where the smaller angle among the angles formed by the length direction and the high-density portion DH is 45 degrees or less. In the sanitary napkin 1, as Figure 6As shown, the high-density portion DH is inclined with respect to the longitudinal direction, and has a portion where the smaller angle θ among the angles formed by the imaginary straight line L and the high-density portion DH is 45 degrees or less. Thus, compared with the case where the high-density portion DH parallel to the longitudinal direction is provided, it is easier to promote the introduction of liquid into the high-density portion DH in the longitudinal direction and the retention of liquid in the low-density portion DL as described above, and thus it is easier to promote the diffusion of liquid in the longitudinal direction. In addition, all of the smaller angles among the angles formed by the longitudinal direction and the high-density portion DH may be 45 degrees or less, or there may be a portion where at least one of the smaller angles among the angles formed by the longitudinal direction and the high-density portion DH is 45 degrees or less and a portion having an angle larger than 45 degrees.

[0098] More preferably, when the length in the longitudinal direction of the non-skin side layer 3 is divided into three equal parts, the front part of the three equal parts is defined as the front region 31, the central part is defined as the central region 32, and the rear part is defined as the rear region 33, the high-density portion DH has at least a part continuously extending 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 excretion port in the worn state. By making the high-density portion DH of the non-skin side layer 3 have a part continuously extending from the upper end to the lower end of the central region 32, it is easier to make the excreted excrement diffuse in the longitudinal direction in the central region 32. Thus, the concern about local retention of excrement in the sanitary napkin 1 or the concern about leakage of excrement to the outside in the lateral direction of the sanitary napkin 1 can be reduced.

[0099] <Calculation method of inter-fiber distance>

[0100] Preferably, in the non-skin side layer 3, the average value of the distance between the fibers 3f is 5 μm to 30 μm. 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 using the following mathematical formula based on the assumption of Wrotnowski. By not fusing the fibers 3f in the non-skin side layer 3 with each other, it is easier to reduce the concern that the diffusion of excrement is hindered by the fused part of the fibers, and compared with the case where the average value of the distance between the fibers 3f is less than 5 μm, it is easier to ensure a flow path for diffusing excrement and a region for retaining the absorbed excrement, and compared with the case where the average value of the distance between the fibers 3f is greater than 30 μm, it is easier to introduce the absorbed excrement into the non-skin side layer 3 by capillary action or to promote absorption by the non-skin side layer 3.

[0101] The distance between fibers 3f is obtained by measuring the thickness of the non-skin side layer 3 of the object to be measured and substituting it into the following mathematical formula (1) as described below. First, the non-skin side layer 3 of the object to be measured is cut into a size of 50 mm in the length direction × 50 mm in the width direction to produce a cut piece of the non-skin side layer 3. This cut piece is sandwiched between the skin side layer 2 and the bottom sheet 4 to produce a sanitary napkin for physiological use that uses the non-skin side layer 3 of the object to be measured as an absorbent layer. In the state of the produced sanitary napkin for physiological use, the thickness of the non-skin side layer 3 is measured under a pressure of 49 Pa. The temperature of the measurement environment is 20 ± 2 °C, and the relative humidity is 65 ± 5%. A microscope (manufactured by KEYENCE CORPORATION, VHX-1000) is used as the measurement device. Then, an enlarged photograph of the cross-section of the non-skin side layer 3 is obtained. Components of a known size are simultaneously photographed in the enlarged photograph. The enlarged photograph of the cross-section of the non-skin side layer 3 is aligned with the scale, and the thickness of the non-skin side layer 3 is measured. The operation is performed more than 3 times, and the average value of the 3 times is set as the thickness [mm] of the non-skin side layer 3 in the dry state. In addition, in the case of a laminate, its boundary is judged based on the fiber diameter, and the thickness is calculated.

[0102] Next, the distance between fibers of the fibers constituting the non-skin side layer 3 of the object to be measured is obtained using the following mathematical formula based on the assumption of Wrotnowski. The mathematical formula based on the assumption of Wrotnowski is usually used when obtaining the distance between fibers of the fibers constituting a non-woven fabric. According to the mathematical formula based on the assumption of Wrotnowski, the fiber distance A (μm) is obtained using the thickness h (mm) of the non-woven fabric, the basis weight e (g / m 2 ), the fiber diameter d (μm) of the fibers constituting the non-woven fabric, and the fiber density ρ (g / cm 3 ) and is obtained by the following mathematical formula (1).

[0103] In addition, for the fiber diameter d (μm), a scanning electron microscope (DSC6200 manufactured by Seiko Instruments Inc.) is used to measure the fiber cross-sections of 10 cut fibers, and the average value thereof is set as the fiber diameter.

[0104] For the fiber density ρ (g / cm 3 ), a density gradient tube is used and measured based on the measurement method of the density gradient tube method described in JIS L1015 Test Method for Chemical Fibre Staple Fibres.

[0105] For the basis weight e (g / m 2 ), it is cut into a predetermined size (such as 0.12 m × 0.06 m), and after weighing, the basis weight is obtained by calculation using the following mathematical formula.

[0106] Weight ÷ Area calculated based on a predetermined size = Weight per unit area (g / m 2 )

[0107] [Equation 1]

[0108]

[0109] Regarding the distance between fibers 3f of the non-skin side layer 3 of the sanitary napkin 1 of the present embodiment, for each region of the high-density portion DH and the low-density portion DL, the calculation is performed based on the above-mentioned equation (1).

[0110] [High-density portion DH]

[0111] Thickness h of the non-woven fabric: 0.32 mm

[0112] Weight per unit area e: 121.00 g / m 2

[0113] Fiber diameter d of the fibers 3f constituting the non-skin side layer 3: 17.00 μm

[0114] Fiber density ρ: 1.360 g / cm 3

[0115] When calculating the fiber distance A based on these values, the fiber distance A of the high-density portion DH becomes 11.75 μm.

[0116] [Low-density portion DL]

[0117] Thickness h of the non-woven fabric: 0.79 mm

[0118] Weight per unit area e: 121.00 g / m 2

[0119] Fiber diameter d of the fibers 3f constituting the non-skin side layer 3: 17.00 μm

[0120] Fiber density ρ: 1.360 g / cm 3

[0121] When calculating the fiber distance A based on these values, the fiber distance A of the low-density portion DL becomes 27.92 μm.

[0122] In addition, as described above, the sanitary napkin 1 has a non-skin side layer 3 and a skin side layer 2 (skin side sheet). The skin side layer 2 has voids (first voids) formed by a plurality of fibers 2f, and the non-skin side layer 3 has voids (second voids) formed by a plurality of fibers 3f. For each of these voids, preferably, the proportion of the voids (second voids) in the non-skin side layer 3 in the void proportion evaluation test for quantitatively evaluating the proportion of voids in a predetermined area is smaller than the proportion of the voids (first voids) in the skin side layer 2 in the void proportion evaluation test. In the sanitary napkin 1, by providing a high-density portion DH in the entire area of the non-skin side layer 3, the proportion of the voids (second voids) in the non-skin side layer 3 in the void proportion evaluation test is made smaller than the proportion of the voids (first voids) in the skin side layer 2 in the void proportion evaluation test. When the sanitary napkin 1 absorbs excrement, it is easy to introduce the excrement from the skin side layer 2 to the non-skin side layer 3 with a smaller proportion of voids by capillary action, and it is easy to promote the diffusion of the excrement in the non-skin side layer 3. In addition, in the worn state, it is easy to reduce the excrement staying on the skin side layer 2, so that the discomfort caused by the contact between the excrement and the wearer's skin can be reduced.

[0123] In addition, as a method of making the proportion of the voids (second voids) in the non-skin side layer 3 in the void proportion evaluation test smaller than the proportion of the voids (first voids) in the skin side layer 2 in the void proportion evaluation test, the method is not limited to the method of providing a high-density region DL in the non-skin side layer 3. For example, it may be that the entire non-skin side layer 3 is compressed in the thickness direction and the non-skin side layer 3 is flattened in the thickness direction, whereby the voids formed by the fibers 3f are made smaller. In addition, the thickness (fiber diameter) of the fibers 3f in the non-skin side layer 3 may be made thinner than the thickness (fiber diameter) of the fibers 2f in the skin side layer 2. Furthermore, latent crimped fibers having a stronger crimping property than the fibers 2f in the skin side layer 2 may be used for the fibers 3f in the non-skin side layer 3.

[0124] <Void proportion evaluation test method>

[0125] The void proportion evaluation test for the skin side layer 2 and the non-skin side layer 3 of the sanitary napkin 1 of the present embodiment was measured by Toray Research Center, Inc.

[0126] The void proportion evaluation test can be performed, for example, by the following method.

[0127] First, X-ray CT measurements are performed on the skin side layer 2 and the non-skin side layer 3, respectively. Using a high-resolution 3D X-ray microscope nano3DX manufactured by Rigaku Corporation, non-destructive tomography (CT measurement) is performed under the following conditions.

[0128] X-ray source: Cu

[0129] Tube voltage - tube current: 40 kV - 30 mA

[0130] Detector: sCMOS camera (lens: 1080)

[0131] Resolution: 2.51 μm / voxel

[0132] Measurement regions (predetermined regions) of the skin side layer 2 and the non - skin side layer 3 are randomly extracted from the three - dimensional data obtained by shooting, and the voids are analyzed. In addition, the measurement regions for this analysis are rectangular parallelepipeds (which can also be cubes) within an arbitrary range in the plane direction of the skin side layer 2 and the non - skin side layer 3 and having a length in the thickness direction equal to the thicknesses H2 and H3 of the skin side layer 2 and the non - skin side layer 3.

[0133] The tomographic image obtained by X - ray CT becomes an image in which low - density (void) components through which X - rays easily pass are represented by black, and high - density (fiber) components that easily absorb X - rays are represented by white. Based on this image, the void ratio of the measurement regions of the skin side layer 2 and the non - skin side layer 3 is calculated.

[0134] The void ratios of the skin side layer 2 and the non - skin side layer 3 can be calculated as follows: Based on the tomographic image obtained by X - ray CT, the volume of the voids and the volume of the measurement regions in the skin side layer 2 and the non - skin side layer 3 are obtained. For example, the void ratio of the non - skin side layer 3 is as described below.

[0135] Void ratio of the non - skin side layer 3=(Volume of the voids in the non - skin side layer 3) / (Volume of the non - skin side layer 3)

[0136] In addition, 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.

[0137] In the above - mentioned embodiment, an adhesive such as a hot - melt adhesive is provided between the members overlapping in the thickness direction to fix the members, but it is not limited thereto. An adhesive may not be provided between the skin side layer 2 and the non - skin side layer 3. In particular, it may be that no adhesive is provided between the skin side layer 2 and the non - skin side layer 3 at the central portion in the width direction of the sanitary napkin 1. Thereby, the concern that the adhesive hinders the absorption of excrement in the skin side layer 2 and the non - skin side layer 3 can be reduced, the concern that it hinders the diffusion of excrement from the skin side layer 2 to the non - skin side layer 3 can be reduced, and the concern that excrement stays in the skin side layer 2 can be reduced.

[0138] ===Other embodiments===

[0139] The above-described embodiments are for the purpose of easily understanding the present invention and are not intended to limit the interpretation of the present invention. The present invention can be changed and improved without departing from its gist, and it goes without saying that the present invention includes equivalents thereof.

[0140] Explanation of Reference Numerals

[0141] 1. Sanitary napkin (physiological sanitary napkin, absorbent article); 1w. Wing portion; 2. Skin-side layer (skin-side sheet); 2f. Potentially shrinkable fiber (fiber); 3. Non-skin-side layer (non-woven fabric sheet); 31. Front-side region; 32. Central region; 33. Rear-side region; 3f. Potentially shrinkable fiber (fiber); 4. Backsheet (outer layer); 5. Side sheet; 10. Absorbent layer; 20. Compression portion; DH. High-density portion; DL. Low-density portion.

Claims

1. A non-woven fabric sheet for use in absorbent articles, characterized in that, the non-woven fabric sheet has a plurality of fibers including latent crimped fibers, and has a linear high-density portion where the density of the fibers is higher than that of the surrounding area, the thickness of the high-density portion is thinner than that of the surrounding area, and the plurality of fibers are not fused to each other.

2. The non-woven fabric sheet according to claim 1, characterized in that, the non-woven fabric sheet is an absorbent body for absorbing liquid.

3. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the non-woven fabric sheet has a length direction, a width direction and a thickness direction, the length in the length direction of the non-woven fabric sheet is longer than the length in the width direction, the surrounding area of the high-density portion is a low-density portion where the density of the fibers is lower than that of the high-density portion, the low-density portions are respectively adjacent to both sides in the length direction of the high-density portion.

4. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the non-woven fabric sheet has a length direction, a width direction and a thickness direction, the length in the length direction of the non-woven fabric sheet is longer than the length in the width direction, the high-density portion is inclined with respect to the length direction, and has a portion where the smaller angle among the angles formed by the length direction and the high-density portion is 45 degrees or less.

5. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the non-woven fabric sheet has a length direction, a width direction and a thickness direction, the length in the length direction of the non-woven fabric sheet is longer than the length in the width direction, when the length in the length direction of the non-woven fabric sheet is divided into three equal parts and the central portion in the length direction is set as the central region, the high-density portion has at least a portion continuously extending from the upper end to the lower end of the central region.

6. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the average value of the distance between the fibers is 5 μm or more and 30 μm or less.

7. The non-woven fabric sheet according to claim 1 or 2, characterized in that, a bottomed concave portion is formed in the high-density portion.

8. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the weight per unit area of the fibers of the non-woven fabric sheet is 80 gsm or more and 200 gsm or less.

9. The non-woven fabric sheet according to claim 1 or 2, characterized in that, the non-woven fabric sheet is for use in absorbent articles, the non-woven fabric sheet is provided at the crotch position of the wearer in the wearing state of the absorbent article.

10. An absorbent article having the non-woven fabric sheet according to claim 1 or 2, characterized in that, the absorbent article has a thickness direction, and has a skin-side sheet provided at a position closer to the skin side than the non-woven fabric sheet, the skin-side sheet has a first void formed by a plurality of fibers, the non-woven fabric sheet has a second void formed by the plurality of fibers, in a void ratio evaluation test for quantitatively evaluating the ratio of the voids in a predetermined region, the ratio of the second voids of the non-woven fabric sheet is smaller than the ratio of the first voids of the skin-side sheet.

11. An absorbent article, comprising the nonwoven fabric sheet according to claim 1 or 2, characterized in that the absorbent article has a longitudinal direction, a width direction, and a thickness direction, the length of the nonwoven fabric sheet in the longitudinal direction is longer than the length in the width direction, the absorbent article has a skin-side sheet disposed at a position closer to the skin than the nonwoven fabric sheet, in the central portion in the width direction, no adhesive is provided between the nonwoven fabric sheet and the skin-side sheet.

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