Non-woven fabric for liquid-permeable sheet of absorbent article, absorbent article including said non-woven fabric, and method for producing said non-woven fabric

Abstract

To provide a non-woven fabric which, when used as a liquid-permeable sheet of an absorbent article for absorbing menstrual blood, is less likely to be colored red due to menstrual blood and has an excellent property of hiding transferred menstrual blood inside the absorbent article.SOLUTION: A non-woven fabric 1 for a liquid permeable sheet of an absorbent article for absorbing menstrual blood, Includes: a heat-shrunk fiber layer 3 including a heat-shrunk fibers 5 obtained by thermally shrinking heat-shrinkable hydrophobic fibers. In the heat-shrunk fiber layer 3, the heat-shrunk fibers 5 extend in a first direction D1 and a second direction D2. The heat-shrunk fiber layer 3 includes a plurality of hydrophilic regions 7 and a hydrophobic region 9. The plurality of hydrophilic regions 7 extend continuously or intermittently in a direction along the first direction D1, and are spaced apart in the second direction D2. In each of the plurality of hydrophilic regions 7, a hydrophilic fibers 13 penetrate the heat-shrunk fibers 5 from a first face S1 to a second face S2 in a thickness direction. In the heat-shrunk fiber layer 3, the heat-shrunk fibers 5 are disposed on the first face S1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a nonwoven fabric for a liquid-permeable sheet of an absorbent article, an absorbent article including the nonwoven fabric as a liquid-permeable sheet, and a method for manufacturing the nonwoven fabric.

Background Art

[0002] Studies have been conducted on nonwoven fabrics for liquid-permeable sheets of absorbent articles. For example, Patent Document 1 discloses an absorbent article including a topsheet, a backsheet, and an absorbent core disposed between the topsheet and the backsheet, where the topsheet has a first side and a second side, the first side faces the body, and the second side is in fluid communication with the absorbent core, and the topsheet further includes: a. a first relatively hydrophobic component and a second relatively hydrophilic component; b. the relatively hydrophilic component extends through the relatively hydrophobic component and is disposed on both sides of the side of the topsheet; and c. when the absorbent article is tested by a spray acquisition and rewetting test method, it exhibits a rewetting value of less than about 94 mg and a fluid acquisition rate of at least about 0.10 ml / s. An absorbent article characterized thereby is disclosed. Patent Document 1 aims to improve, among other things, the topsheet for disposable absorbent articles that can provide a high spray acquisition rate and can also provide improved dryness.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 does not disclose a nonwoven fabric for a liquid-permeable sheet of an absorbent article for absorbing menstrual blood according to the present disclosure. Accordingly, an object of the present disclosure is to provide a nonwoven fabric that is less likely to be colored red by menstrual blood and has excellent concealability of menstrual blood that has migrated into an absorbent article when used as a liquid-permeable sheet of the absorbent article that absorbs menstrual blood.

Means for Solving the Problems

[0005] The present inventors have provided a nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood, the nonwoven fabric including a post-heat-shrinkage fiber layer containing post-heat-shrinkage fibers obtained by heat-shrinking hydrophobic heat-shrinkable fibers, and having a first direction, a second direction, and a thickness direction that are orthogonal to each other. The post-heat-shrinkage fiber layer has a first surface and a second surface. In the post-heat-shrinkage fiber layer, the post-heat-shrinkage fibers extend in the first direction and the second direction. The post-heat-shrinkage fiber layer includes a plurality of hydrophilic regions and a hydrophobic region. The plurality of hydrophilic regions extend continuously or intermittently in a direction along the first direction, are spaced apart in the second direction, and in each of the plurality of hydrophilic regions, hydrophilic fibers penetrate the post-heat-shrinkage fibers in the thickness direction from the first surface to the second surface. In the post-heat-shrinkage fiber layer, the post-heat-shrinkage fibers are arranged on the first surface.

Advantages of the Invention

[0006] When the nonwoven fabric according to the present disclosure is used as a liquid-permeable sheet of an absorbent article that absorbs menstrual blood, it is less likely to be colored red by menstrual blood and has excellent concealability of menstrual blood that has migrated into the absorbent article.

Brief Description of the Drawings

[0007]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Specifically, the present disclosure relates to the following aspects. [Aspect 1A] A nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood, comprising a post-heat-shrinkage fiber layer containing post-heat-shrinkage fibers obtained by heat-shrinking hydrophobic heat-shrinkable fibers, and having a first direction, a second direction, and a thickness direction that are orthogonal to each other, The post-heat-shrinkage fiber layer has a first surface and a second surface, In the post-heat-shrinkage fiber layer, the post-heat-shrinkage fibers extend in the first direction and the second direction, The post-heat-shrinkage fiber layer includes a plurality of hydrophilic regions and a hydrophobic region, The plurality of hydrophilic regions extend continuously or intermittently in a direction along the first direction, are spaced apart in the second direction, and in each of the plurality of hydrophilic regions, hydrophilic fibers penetrate the post-heat-shrinkage fibers in the thickness direction from the first surface to the second surface, In the post-heat-shrinkage fiber layer, the post-heat-shrinkage fibers are disposed on the first surface, A nonwoven fabric characterized by the above.

[0009] The non-woven fabric has a predetermined hydrophobic region and hydrophilic region. Therefore, when the non-woven fabric is used as the liquid-permeable sheet of an absorbent article that absorbs menstrual blood, and the first surface of the non-woven fabric constitutes the skin-contact surface of the liquid-permeable sheet (hereinafter, may be simply referred to as "when the non-woven fabric is used in the absorbent article", etc.), the menstrual blood reaching the first surface of the non-woven fabric is unlikely to remain in the hydrophobic region containing hydrophobic curled fibers and is unlikely to penetrate into the hydrophobic region, and is likely to migrate into the absorbent article through the hydrophilic region penetrating in the thickness direction from the first surface to the second surface. Therefore, when the non-woven fabric is used in the absorbent article, the non-woven fabric is less likely to be colored red by menstrual blood.

[0010] After the menstrual blood has migrated into the absorbent article, at least the first surface of the hydrophobic region of the non-woven fabric contains curled fibers after shrinkage, so it is difficult to transmit visible light and it is difficult to visually recognize the menstrual blood that has migrated into the absorbent article. Further, since the hydrophobic region of the non-woven fabric contains hydrophobic curled fibers after shrinkage, it is difficult for the menstrual blood that has migrated into the absorbent article to physically penetrate (it is difficult to cause rewetting).

[0011] Also, in the hydrophilic region, since the fibers after heat shrinkage extend in the first direction and the second direction, when the non-woven fabric is used in the absorbent article, even when a force such as body pressure is applied, the hydrophilic region is difficult to open, and it becomes difficult to visually recognize the menstrual blood held by the hydrophilic fibers and the menstrual blood absorbed into the absorbent article from the outside of the absorbent article. From the above, when the non-woven fabric is used in the absorbent article, the non-woven fabric is less likely to be colored red by menstrual blood and has excellent concealment of the menstrual blood that has migrated into the absorbent article.

[0012] [Aspect 1B] A non-woven fabric for a liquid-permeable sheet of an absorbent article that absorbs liquid, which has a heat-shrunk fiber layer containing heat-shrunk fibers obtained by heat-shrinking heat-shrinkable fibers having hydrophobicity, and has a first direction, a second direction, and a thickness direction that are orthogonal to each other, The heat-shrunk fiber layer has a first surface and a second surface, In the heat-shrunk fiber layer, the heat-shrunk fibers extend in the first direction and the second direction, The heat-shrunk fiber layer includes a plurality of hydrophilic regions and a hydrophobic region, The plurality of hydrophilic regions extend continuously or intermittently in a direction along the first direction, are spaced apart in the second direction, and in each of the plurality of hydrophilic regions, hydrophilic fibers penetrate the heat-shrunk fibers in the thickness direction from the first surface to the second surface, In the heat-shrunk fiber layer, the heat-shrunk fibers are arranged on the first surface, A non-woven fabric characterized by this.

[0013] For the same reasons as in Embodiment 1A, when the non-woven fabric is used in an absorbent article that absorbs liquid, the non-woven fabric is difficult to be colored by the liquid and is excellent in concealing the liquid that has migrated into the absorbent article. Note that the "absorbent article that absorbs liquid" is referred to as the "liquid-absorbing absorbent article".

[0014] Examples of the liquid include body fluids such as menstrual blood, blood (e.g., plasma, blood cells), vaginal discharge, breast milk, urine, nasal discharge, saliva, etc. The liquid-absorbing absorbent article is not particularly limited as long as it has an absorbent core. Examples of the liquid-absorbing absorbent article include absorbent articles for women such as sanitary napkins, menstrual panties, tampons, pressure ulcer pads, band-aids, food wrapping sheets, panty liners, breast pads, disposable diapers, urine leakage pads, urine collection sheets, disposable pants, masks, etc.

[0015] Note that the disclosure in this specification can be applied not only to absorbent articles that absorb menstrual blood but also to the liquid-absorbing absorbent articles. In that case, "absorbent article" and "menstrual blood" can be read as "liquid-absorbing absorbent article" and "liquid" respectively, and the terms "red" and "reddish color" can be read as "the color of the liquid" and "the color of the liquid" respectively.

[0016] [Embodiment 2] In at least a part of the plurality of hydrophilic regions, one-side hydrophobic region which is a hydrophobic region existing on one side in the second direction of the hydrophilic region and the other-side hydrophobic region which is a hydrophobic region existing on the other side in the second direction of the hydrophilic region are connected by the fiber after heat shrinkage which are continuously arranged between the one-side hydrophobic region and the other-side hydrophobic region, the nonwoven fabric according to Mode 1A or 1B.

[0017] In the nonwoven fabric, since at least a part of the plurality of hydrophilic regions are connected by the fiber after heat shrinkage which are continuously arranged from the one-side hydrophobic region to the other-side hydrophobic region, when the nonwoven fabric is used for an absorbent article, even when a force such as body pressure is applied, the hydrophilic region is difficult to open, and it becomes difficult to visually recognize menstrual blood retained by the hydrophilic fiber and menstrual blood absorbed inside the absorbent article from outside the absorbent article. As a result, when the nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood that has migrated inside the absorbent article.

[0018] [Mode 3] In the hydrophobic region, in the thickness direction, the fiber after heat shrinkage is arranged from the first surface to the second surface, the nonwoven fabric according to Mode 1A, 1B or 2.

[0019] In the hydrophobic region of the nonwoven fabric, in the thickness direction, the fiber after heat shrinkage is arranged from the first surface to the second surface. Therefore, when the nonwoven fabric is used for an absorbent article, it is difficult for the hydrophobic region to transmit visible light, and it is possible to make it difficult to visually recognize menstrual blood that has migrated inside the absorbent article. Further, since the hydrophobic region of the nonwoven fabric contains hydrophobic curled fibers, it is difficult for the hydrophobic region to physically transmit menstrual blood that has migrated inside the absorbent article (it is difficult to cause rewetting).

[0020] [Mode 4] The nonwoven fabric further includes a hydrophilic fiber layer containing hydrophilic fibers which is joined to the second surface of the fiber layer after heat shrinkage, the nonwoven fabric according to Mode 1A, 1B, 2 or 3.

[0021] The non-woven fabric further includes a predetermined hydrophilic fiber layer containing hydrophilic fibers. Therefore, when the non-woven fabric is used in an absorbent article, the hydrophilic fiber layer can diffuse the menstrual blood that has passed through the non-woven fabric (liquid-permeable sheet) in the planar direction, and it becomes easier to transfer the menstrual blood to a member adjacent to the menstrual blood holding member (for example, an absorber). As a result, while diffusing the menstrual blood from the excretory opening contact area in the first direction and the second direction, it becomes easier to transfer the menstrual blood to a member adjacent to the menstrual blood holding member side, and thus it is less likely for the redness of the menstrual blood holding member to become partially concentrated. Therefore, when the non-woven fabric is used in an absorbent article, the non-woven fabric is excellent in concealing menstrual blood.

[0022] [Aspect 5] The hydrophilic fiber layer includes a plurality of protruding portions that protrude in the thickness direction from the second surface of the fiber layer after heat shrinkage and extend in a direction along the first direction. At least a part of the plurality of protruding portions is arranged so as to overlap the hydrophobic region in a plan view from the thickness direction of the non-woven fabric. The non-woven fabric according to Aspect 4.

[0023] In the non-woven fabric, the hydrophilic fiber layer includes a predetermined plurality of protruding portions. Therefore, when the non-woven fabric is used in an absorbent article, it becomes easier to transfer the menstrual blood that has passed through the non-woven fabric in the thickness direction through the hydrophilic region to a member adjacent to the menstrual blood holding member side via the protruding portions. Also, the protruding portions arranged so as to overlap the hydrophobic region make it easier for the menstrual blood to transfer to a region that overlaps the hydrophobic region of the member adjacent to the menstrual blood holding member side in the thickness direction. As a result, it becomes less likely for the redness of the menstrual blood holding member to become partially concentrated. Therefore, when the non-woven fabric is used in an absorbent article, the non-woven fabric is excellent in concealing menstrual blood.

[0024] [Aspect 6] The non-woven fabric according to Aspect 5, wherein at least a part of the plurality of protruding portions is arranged so as to further overlap a part of the plurality of hydrophilic regions in a plan view from the thickness direction of the non-woven fabric.

[0025] In the nonwoven fabric, at least a part of the plurality of protruding portions is arranged so as to further overlap with a part of the plurality of hydrophilic regions in a plan view from the thickness direction of the nonwoven fabric. Therefore, when the nonwoven fabric is used in an absorbent article, the menstrual blood that has passed through the nonwoven fabric through the hydrophilic region is easily transferred via the protruding portions to a region that overlaps with the hydrophobic region of the member adjacent to the menstrual blood holding member side in the thickness direction. As a result, it becomes difficult for the reddish part of the menstrual blood holding member to become partially dark. Therefore, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood.

[0026] [Aspect 7] The nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 6, wherein the plurality of hydrophilic regions are arranged so as to have a pitch in the second direction of 0.3 to 2.0 mm.

[0027] The nonwoven fabric is arranged such that the plurality of hydrophilic regions have a predetermined pitch. Therefore, when the nonwoven fabric is used in an absorbent article, it becomes easy for menstrual blood to transfer through the plurality of hydrophilic regions to the member adjacent to the menstrual blood holding member side, and it becomes difficult for menstrual blood to remain on the first surface of the hydrophobic region. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood.

[0028] [Aspect 8] The nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 7, wherein the nonwoven fabric is a spunlace nonwoven fabric. Since the nonwoven fabric is a spunlace nonwoven fabric, it is easier to ensure the thickness of the nonwoven fabric compared to a nonwoven fabric having a squeezing portion. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood. Also, the nonwoven fabric has an excellent touch.

[0029] [Aspect 9] The nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 8, wherein the nonwoven fabric does not include a heat-sealing portion where the fibers are heat-sealed after heat shrinkage.

[0030] Since the nonwoven fabric does not have a predetermined heat-sealed portion, it is easier to ensure the thickness of the nonwoven fabric compared to a nonwoven fabric having a heat-sealed portion. As a result, when the nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood. Further, the nonwoven fabric has an excellent texture.

[0031] [Aspect 10] The nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 9, wherein the hydrophilic fiber is a cellulose-based fiber.

[0032] In the nonwoven fabric, since the hydrophilic fiber is a cellulose-based fiber, when the nonwoven fabric is used for an absorbent article, it becomes easier to draw menstrual blood into the absorbent article through a plurality of hydrophilic regions. As a result, it becomes difficult for menstrual blood to remain on the first surface of the hydrophobic region, and thus, when the nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood.

[0033] [Aspect 11] The nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 10, having a thickness of 0.3 to 2.5 mm. Since the nonwoven fabric has a predetermined thickness, when the nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood.

[0034] [Aspect 12] An absorbent article comprising the nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 11 as a liquid-permeable sheet. The absorbent article is difficult to be colored red by menstrual blood and is excellent in concealing menstrual blood that has migrated into the absorbent article.

[0035] [Aspect 13] A method for manufacturing a nonwoven fabric according to any one of Aspects 1A, 1B, and 2 to 11, A preparation step of preparing a laminated web in which a hydrophilic fiber sheet containing the hydrophilic fiber is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fiber, A water jet treatment step of subjecting the laminated web to water jet treatment from the hydrophilic fiber sheet side, A nonwoven fabric forming step of heating the water jet-treated laminated web to thermally shrink the heat-shrinkable fibers to form the post-heat-shrinkage fibers, thereby forming the nonwoven fabric, A manufacturing method comprising.

[0036] The above manufacturing method can simply manufacture the nonwoven fabric according to Embodiment 1.

[0037] [Embodiment 14] The method according to Embodiment 13, wherein the hydrophilic fiber sheet has a wet strength of 2.0 N / 25 mm or less in any direction. In the above manufacturing method, since the hydrophilic fiber sheet has a predetermined wet strength, the nonwoven fabric according to Embodiment 1 can be simply manufactured.

[0038] [Embodiment 15] The method according to Embodiment 13 or 14, wherein the hydrophilic fiber sheet is a web, nonwoven fabric or tissue paper containing the hydrophilic fibers.

[0039] In the above manufacturing method, since the hydrophilic fiber sheet is composed of a predetermined one, the nonwoven fabric according to Embodiment 1 can be simply manufactured.

[0040] [Embodiment 16] In the above water jet treatment step, while transporting the laminated web in the transport direction, a water jet device in which a plurality of nozzles having an inner diameter of 0.03 to 0.17 mm are arranged at a pitch in a direction orthogonal to the transport direction of 0.3 to 2.0 mm is arranged such that the distance between the plurality of nozzles and the laminated web is 10 to 60 mm, and water is sprayed onto the laminated web from the plurality of nozzles at a water pressure of 1 to 15 MPa to subject the laminated web to water jet treatment. The method according to any one of Embodiments 13 to 15.

[0041] In the above manufacturing method, since the laminated web is subjected to water jet treatment under predetermined conditions, the nonwoven fabric according to Embodiment 1 can be easily manufactured.

[0042] [Embodiment 17] In the above nonwoven fabric forming step, by thermally shrinking the heat-shrinkable fiber, the nonwoven fabric having a thickness greater than that of the laminated web subjected to water jet treatment is formed, according to any one of Embodiments 13 to 16.

[0043] In the above manufacturing method, by thermally shrinking the heat-shrinkable fiber, a nonwoven fabric having a predetermined thickness is formed, so that the formed nonwoven fabric is excellent in concealment and touch.

[0044] The nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood according to the present disclosure, the absorbent article including the nonwoven fabric as a liquid-permeable sheet, and the manufacturing method of the nonwoven fabric will be described in detail below. Note that the above absorbent article will be described together with the location of the nonwoven fabric.

[0045] The nonwoven fabric according to the present disclosure is a nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood. In this specification, the "nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood" may be simply referred to as the 'nonwoven fabric'.

[0046] [Nonwoven fabric] FIG. 1 is a diagram for explaining a nonwoven fabric 1 according to one embodiment of the present disclosure (hereinafter referred to as the "first embodiment"). Specifically, FIG. 1 is a perspective view of the nonwoven fabric 1 according to the first embodiment. The nonwoven fabric 1 is a nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood. The nonwoven fabric 1 has a first direction D1, a second direction D2, and a thickness direction T that are orthogonal to each other. The nonwoven fabric 1 includes a post-thermal-shrinkage fiber layer 3 including post-thermal-shrinkage fibers 5 obtained by thermally shrinking hydrophobic heat-shrinkable fibers. Specifically, the heat-shrinkable fiber is a latent crimp fiber, and the post-thermal-shrinkage fiber 5 is a crimped latent crimp fiber.

[0047] After heat shrinkage, the fiber layer 3 has a first surface S1 that forms a skin contact surface when used for a liquid-permeable sheet, and a second surface S2 on the side opposite to the first surface S1. In the heat-shrunk fiber layer 3, the heat-shrunk fibers 5 extend in the first direction D1 and the second direction D2 while being curled.

[0048] The heat-shrunk fiber layer 3 is partitioned into a plurality of hydrophilic regions 7 and a plurality of hydrophobic regions 9. The plurality of hydrophilic regions 7 continuously extend in parallel with the first direction D1 and are arranged at a predetermined pitch P in the second direction D2. In each of the plurality of hydrophilic regions 7, the hydrophilic fibers 13 penetrate the heat-shrunk fibers 5 in the thickness direction T from the first surface S1 to the second surface S2. The hydrophilic fibers 13 are cellulose-based fibers, specifically, rayon fibers. In each of the plurality of heat-shrunk fiber layers 3, the heat-shrunk fibers 5 are arranged so as to reach from the first surface S1 to the second surface S2 in the thickness direction T.

[0049] In addition, in FIG. 1, from the viewpoint of facilitating understanding of the invention, the hydrophilic fibers 13 are shown thicker than the heat-shrunk fibers 5, but this does not mean the relationship between the actual fiber diameters of the hydrophilic fibers 13 and the heat-shrunk fibers 5. The same applies to the fiber lengths of the hydrophilic fibers 13 and the heat-shrunk fibers 5. Also, in FIG. 1, the heat-shrunk fibers 5 are depicted in a spiral shape, but this does not represent the actual curled state, orientation, etc. of the heat-shrunk fibers.

[0050] Since the nonwoven fabric 1 includes a plurality of hydrophilic regions 7 and a plurality of hydrophobic regions 9, when the nonwoven fabric 1 is used for an absorbent article, the nonwoven fabric 1 is less likely to be colored red by menstrual blood and has excellent concealability of the menstrual blood that has migrated inside the absorbent article.

[0051] In each of the plurality of hydrophilic regions 7, one-side hydrophobic region 9a, which is a hydrophobic region 9 existing on one side in the second direction D2 of the hydrophilic region 7, and the other-side hydrophobic region 9b, which is a hydrophobic region 9 existing on the other side in the second direction D2, are connected by the heat-shrunk fiber 5 that is continuous. In other words, each of the plurality of hydrophilic regions 7 extends parallel to the first direction D1 and has no fracture surface that breaks the heat-shrunk fiber 5 and penetrates in the thickness direction T. Thereby, when the nonwoven fabric 1 is used for an absorbent article, even when a force such as body pressure is applied, the plurality of hydrophilic regions 7 are difficult to open, and the menstrual blood held by the hydrophilic fibers and the menstrual blood absorbed inside the absorbent article are difficult to be visually recognized from the outside of the absorbent article.

[0052] The nonwoven fabric 1 further includes a hydrophilic fiber layer 11 containing hydrophilic fibers 13, which is joined to the second surface S2 of the heat-shrunk fiber layer 3. Specifically, the hydrophilic fiber layer 11 is composed of the hydrophilic fibers 13, and has a plurality of protruding portions 15 that protrude in the thickness direction T from the second surface S2 of the heat-shrunk fiber layer 3 in a direction opposite to the heat-shrunk fiber layer 3 and extend parallel to the first direction D1. Each of the plurality of protruding portions 15 overlaps with the hydrophobic region 9 in a plan view from the thickness direction T of the nonwoven fabric 1, and is arranged so as to overlap with two hydrophilic regions 7 adjacent to the hydrophobic region 9 in the second direction D2. Thereby, when the nonwoven fabric 1 is used for an absorbent article, the menstrual blood that has permeated the nonwoven fabric 1 in the thickness direction T through the hydrophilic region 7 is easily transferred to the region that overlaps with the hydrophobic region 9 in the thickness direction T of the member adjacent to the menstrual blood holding member side via the protruding portion 15.

[0053] The nonwoven fabric according to the present disclosure is a nonwoven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood. The absorbent article is not particularly limited as long as it includes a menstrual blood retention member for absorbing menstrual blood, and examples thereof include absorbent articles for women, such as sanitary napkins and sanitary panties. Examples of the menstrual blood retention member include an absorbent core, an absorber including an absorbent core and a core wrap covering the absorbent core, and the like. Examples of the liquid-permeable sheet include a liquid-permeable top sheet having a skin-contact surface, a core wrap covering the absorbent core, a liquid diffusion sheet (second sheet) disposed between the top sheet and the absorbent core, and the like. Examples of the member adjacent to the liquid-permeable sheet on the side of the menstrual blood retention member include the menstrual blood retention member, the second sheet, the core wrap, and the like.

[0054] The nonwoven fabric according to the present disclosure has a first direction, a second direction, and a thickness direction that are orthogonal to each other. Examples of the first direction and the second direction include, for example, the conveyance direction during manufacturing and the orthogonal direction orthogonal to the conveyance direction, respectively. In this specification, a direction including the first direction and the second direction may be referred to as a planar direction.

[0055] The nonwoven fabric according to the present disclosure includes a heat-shrunk fiber layer including heat-shrunk fibers obtained by heat-shrinking hydrophobic heat-shrinkable fibers. The heat-shrunk fiber layer includes a first surface and a second surface extending in the planar direction. Examples of the heat-shrinkable fibers include fibers whose actual fiber length is shortened by heat treatment, fibers whose apparent fiber length is shortened by heat treatment (for example, latent crimpable fibers whose apparent fiber length is shortened by the appearance of crimps), and the like. Examples of the latent crimpable fibers include composite fibers including two types of thermoplastic resins having different shrinkage rates, such as eccentric core-sheath type composite fibers and side-by-side type composite fibers.

[0056] Examples of the composite fiber include eccentric core-sheath type composite fibers in which the core is made of polyethylene terephthalate resin and the sheath is made of polyethylene resin; eccentric core-sheath type composite fibers in which the core is made of polypropylene resin and the sheath is made of polyethylene resin; eccentric core-sheath type composite fibers in which the core is made of high melting point polypropylene resin and the sheath is made of low melting point polypropylene resin; side-by-side type composite fibers made of polyethylene terephthalate resin (PET) and low melting point polyethylene terephthalate resin; side-by-side type composite fibers made of polyethylene terephthalate resin and polyethylene resin; side-by-side type composite fibers made of polypropylene resin and polyethylene resin, and the like.

[0057] The heat-shrinkable fiber preferably has an average fiber length of 20 mm or more, and more preferably 30 mm or more. Also, the heat-shrinkable fiber preferably has an average fiber length of 70 mm or less, and more preferably 60 mm or less. Thereby, the non-woven fabric according to the present disclosure is excellent in formability.

[0058] The heat-shrinkable fiber preferably has a fineness of 0.5 dtex or more, and more preferably 1.0 dtex or more. Also, the heat-shrinkable fiber preferably has a fineness of 8.0 dtex or less, and more preferably 7.0 dtex or less. Thereby, since the non-woven fabric according to the present disclosure can easily secure a certain thickness, it has an excellent touch feeling, is less likely to cause rewet back, and since a certain number of heat-shrinkable fibers can be ensured, the non-woven fabric is excellent in concealability.

[0059] In the fiber layer after heat shrinkage of the non-woven fabric according to the present disclosure, the fibers after heat shrinkage extend in the first direction and the second direction. The fiber layer after heat shrinkage includes a plurality of hydrophilic regions and single or a plurality of hydrophobic regions. The fiber layer after heat shrinkage may be partitioned into a plurality of hydrophilic regions and single or a plurality of hydrophobic regions.

[0060] In the planar direction, the plurality of hydrophilic regions extend continuously or intermittently along the first direction and are spaced apart in the second direction. Further, in the thickness direction, in each of the plurality of hydrophilic regions, hydrophilic fibers penetrate the post-heat-shrinkage fibers in the thickness direction from the first surface to the second surface. In the present disclosure, the "direction along the first direction" means the first direction and a direction having an intersection angle of preferably less than 45°, more preferably 30° or less, still more preferably 20° or less, and even more preferably 5° or less.

[0061] Examples of the non-woven fabric in which the post-heat-shrinkage fiber layer includes a plurality of hydrophilic regions and a single hydrophobic region include non-woven fabrics in which each of the plurality of hydrophilic regions extends intermittently in the direction along the first direction. In other words, non-woven fabrics in which a plurality of hydrophilic regions extending intermittently in the direction along the first direction are spaced apart in the first direction and the second direction within a single hydrophobic region are included.

[0062] Examples of the non-woven fabric in which the post-heat-shrinkage fiber layer includes a plurality of hydrophilic regions and a plurality of hydrophobic regions include non-woven fabrics in which each of the plurality of hydrophilic regions extends continuously in the direction along the first direction, each of the plurality of hydrophobic regions extends continuously in the direction along the first direction, and the hydrophilic regions and the hydrophobic regions are alternately arranged in the second direction.

[0063] The plurality of hydrophilic regions can be spaced apart in the second direction at a predetermined pitch. The predetermined pitch is preferably 0.3 mm or more, more preferably 0.5 mm or more, and still more preferably 0.7 mm or more. Further, the predetermined pitch is preferably 2.0 mm or less, more preferably 1.7 mm or less, and still more preferably 1.5 mm or less. Thereby, when the non-woven fabric is used for an absorbent article, menstrual blood is easily transferred through the plurality of hydrophilic regions to a member adjacent to the menstrual blood holding member side, and it is difficult for menstrual blood to remain on the first surface of the hydrophobic region.

[0064] As the hydrophilic fiber, those used as hydrophilic fibers in the relevant technical field can be adopted. For example, water-absorbent fibers such as cellulose-based fibers, and non-water-absorbent fibers such as hydrophilized synthetic fibers can be mentioned. Examples of the cellulose-based fibers include natural cellulose fibers, regenerated cellulose fibers, purified cellulose fibers, and semi-synthetic cellulose fibers. Examples of the natural cellulose fibers include plant fibers such as pulp fibers, seed hair fibers (e.g., cotton fibers), bast fibers (e.g., hemp), leaf vein fibers (e.g., manila hemp), and fruit fibers (e.g., coconut).

[0065] The pulp fibers include those known in the relevant technical field, and examples thereof include wood pulp fibers and non-wood pulp fibers. Examples of the wood pulp fibers include softwood pulp fibers and hardwood pulp fibers. Examples of the non-wood pulp fibers include straw pulp fibers, bagasse pulp fibers, rush pulp fibers, kenaf pulp fibers, ramie pulp fibers, bamboo pulp fibers, hemp pulp fibers, cotton pulp fibers (e.g., cotton linter fibers), and the like. The pulp fibers may be waste paper, recycled recycled pulp fibers, or the like.

[0066] Examples of the cotton fibers include upland cotton fibers (e.g., upland cotton), barbadense cotton fibers, arboreum cotton fibers, and herbaceum cotton fibers. Further, the cotton fibers can be organic cotton fibers or pre-organic cotton (trademark) fibers. Organic cotton fibers mean cotton certified by GOTS (Global Organic Textile Standard).

[0067] Examples of the above-mentioned regenerated cellulose fibers include rayon, such as viscose rayon obtained from viscose, polynosic, and modal, and fibers such as cuprammonium rayon (also referred to as "cupra") obtained from a cuprammonium solution of cellulose.

[0068] Examples of the above-mentioned purified cellulose fibers include lyocell. Specifically, it is obtained by dissolving pulp in an aqueous solution of N-methylmorpholine N-oxide to form a spinning dope, and extruding it into a dilute solution of N-methylmorpholine N-oxide to form fibers. The above-mentioned purified cellulose is commercially available, for example, under the trade name Tencel (trademark). Examples of the above-mentioned semi-synthetic fibers include semi-synthetic cellulose, such as acetate fibers, such as triacetate and diacetate fibers.

[0069] Examples of the synthetic fibers in the above-mentioned hydrophilized synthetic fibers include those commonly used in the art, for example, those containing a single component, such as single fibers, or those containing a plurality of components, such as composite fibers. Further, the above-mentioned synthetic fibers can be biomass plastics, recycled materials, etc.

[0070] Examples of the above-mentioned components include polyolefin-based polymers, such as polyethylene and polypropylene; polyester-based polymers, such as terephthalate-based polymers, such as polyethylene terephthalate, polybutylene terephthalate, and polypentylene terephthalate; polyamide-based polymers, such as nylon 6 and nylon 6,6; acrylic-based polymers; polyacrylonitrile-based polymers; and modified products thereof.

[0071] The above-mentioned synthetic fibers are preferably biodegradable synthetic fibers. Thereby, the above-mentioned non-woven fabric is likely to have biodegradability. Examples of the components of the synthetic fiber having biodegradability include polybutylene succinate, poly(hydroxybutyrate / hydroxyhexanoate), polycaprolactone, poly(caprolactone / butylene succinate), poly(butylene succinate / adipate), poly(butylene succinate / carbonate), poly(butylene adipate / terephthalate), polyethylene succinate, or polylactic acid, polyhydroxybutyrate, polyglycolic acid, or cellulose acetate.

[0072] The hydrophilic fiber is preferably a cellulose-based fiber. Thereby, when the nonwoven fabric is used for an absorbent article, menstrual blood is easily drawn into the absorbent article through a plurality of hydrophilic regions. As a result, menstrual blood is less likely to remain on the first surface of the hydrophobic region.

[0073] Except for pulp fibers, the hydrophilic fiber preferably has an average fiber length of 20 mm or more, and more preferably 30 mm or more. Further, the hydrophilic fiber preferably has an average fiber length of 70 mm or less, and more preferably 60 mm or less. Thereby, the nonwoven fabric according to the present disclosure is excellent in formability, and menstrual blood easily moves into the absorbent article through the hydrophilic region. When the hydrophilic fiber is a pulp fiber, for the same reason, the hydrophilic fiber preferably has an average fiber length of 0.1 mm or more, and more preferably 1 mm or more, and the hydrophilic fiber preferably has an average fiber length of 5 mm or less, and more preferably 4 mm or less.

[0074] Except for natural cellulose fibers, the hydrophilic fiber preferably has a fineness of 0.5 dtex or more, and more preferably 1.0 dtex or more. Further, except for natural cellulose fibers, the hydrophilic fiber preferably has a fineness of 5.0 dtex or less, and more preferably 4.0 dtex or less. Thereby, menstrual blood easily moves into the absorbent article through the hydrophilic region.

[0075] In this specification, the average fiber length of fibers including heat-shrinkable fibers and hydrophilic fibers (excluding pulp fibers) is measured in accordance with "A7.1 Method for Measuring Fiber Length" in "A7.1 Fiber Length Measurement" of Annex A of JIS L 1015:2010, "A7.1.1 Method A (Standard Method) Measuring the length of individual fibers on a graduated glass plate". Note that the above method is a test method corresponding to ISO 6989 issued in 1981.

[0076] In this specification, the average fiber length of pulp fibers means the weight-averaged fiber length, and means the L(w) value measured by Kajaani FiberLab fiber properties (off-line) manufactured by Metso Automation.

[0077] The fiber layer after heat shrinkage preferably has the fibers after heat shrinkage on at least the first surface, and in the thickness direction, the fibers after heat shrinkage are arranged from the first surface to the second surface. Thereby, when the non-woven fabric is used for an absorbent article, the hydrophobic region is less likely to transmit visible light, and it is difficult to visually recognize the menstrual blood that has migrated into the absorbent article. Further, since the hydrophobic region of the non-woven fabric contains hydrophobic crimped fibers, it becomes difficult for the menstrual blood that has migrated into the absorbent article to physically pass through (it becomes difficult to cause rewetting).

[0078] In the non-woven fabric according to the present disclosure, preferably in at least a part of a plurality of hydrophilic regions, and more preferably in all of a plurality of hydrophilic regions, one-side hydrophobic regions, which are hydrophobic regions existing on one side in the second direction of the hydrophilic region, and the other-side hydrophobic regions, which are hydrophobic regions existing on the other side in the second direction of the hydrophilic region, are connected by the fibers after heat shrinkage continuously arranged between the one-side hydrophobic regions and the other-side hydrophobic regions. Thereby, when the non-woven fabric is used for an absorbent article, even when a force such as body pressure is applied, the hydrophilic region is less likely to open, and it becomes difficult to visually recognize the menstrual blood held by the hydrophilic fibers and the menstrual blood absorbed inside the absorbent article from the outside of the absorbent article.

[0079] The nonwoven fabric according to the present disclosure may be composed of only a single layer of the fiber layer after heat shrinkage or may be composed of two or more layers including the fiber layer after heat shrinkage and an additional layer in the thickness direction. When the nonwoven fabric according to the present disclosure is composed of two or more layers as described above, the additional layer may be joined to the second surface of the fiber layer after heat shrinkage, that is, the additional layer may not be joined to the first surface of the fiber layer after heat shrinkage. Thereby, the first surface of the fiber layer after heat shrinkage can be used as, for example, the skin contact surface of the topsheet described above, and the nonwoven fabric is less likely to be colored red by menstrual blood, and the concealment of the menstrual blood that has migrated into the absorbent article is excellent.

[0080] The joining of the fiber layer after heat shrinkage and the additional layer is not particularly limited, and examples include joining by entanglement of the fibers constituting the fiber layer after heat shrinkage and the fibers constituting the additional layer, joining due to continuity of the fibers constituting the fiber layer after heat shrinkage and the fibers constituting the additional layer, joining by fusion of the fibers constituting the fiber layer after heat shrinkage and the fibers constituting the additional layer, joining by adhesion of the fiber layer after heat shrinkage and the additional layer, and any combination thereof.

[0081] The nonwoven fabric according to the present disclosure may further include a hydrophilic fiber layer containing hydrophilic fibers joined to the second surface of the fiber layer after heat shrinkage as the additional layer. Thereby, when the nonwoven fabric is used for an absorbent article, the hydrophilic fiber layer can diffuse the menstrual blood that has permeated through the nonwoven fabric (liquid-permeable sheet) in the planar direction and make it easier to transfer the menstrual blood to a member adjacent to the menstrual blood holding member side.

[0082] Examples of the hydrophilic fibers constituting the hydrophilic fiber layer include the same hydrophilic fibers as those constituting the hydrophilic region described above. Also, the hydrophilic fibers constituting the hydrophilic fiber layer and the hydrophilic fibers constituting the hydrophilic region described above may be the same or different.

[0083] The hydrophilic fiber layer can extend in one or both of the direction along the first direction and the direction along the second direction, and preferably extends in the direction along the first direction. Thereby, menstrual blood can be diffused in the direction in which the hydrophilic fiber layer extends.

[0084] The hydrophilic fiber layer can include a plurality of protrusions that protrude in the thickness direction from the second surface of the fiber layer after heat shrinkage and extend in the direction along the first direction. Also, preferably at least a part of the plurality of protrusions, and more preferably all of the plurality of protrusions (each of the plurality of protrusions) are arranged so as to overlap the hydrophobic region in a plan view from the thickness direction of the non-woven fabric. Thereby, when the non-woven fabric is used in an absorbent article, menstrual blood that has permeated the non-woven fabric in the thickness direction through the hydrophilic region is easily transferred to a member adjacent to the menstrual blood holding member side via the protrusions. Also, the protrusions arranged so as to overlap the hydrophobic region facilitate the transfer of menstrual blood to a region that overlaps the hydrophobic region in the thickness direction of a member adjacent to the menstrual blood holding member side.

[0085] Also, preferably at least a part of the plurality of protrusions, and more preferably all of the plurality of protrusions (each of the plurality of protrusions) are arranged so as to further overlap, in a plan view from the thickness direction of the non-woven fabric, preferably a part of the plurality of hydrophilic regions. Thereby, when the non-woven fabric is used in an absorbent article, menstrual blood that has permeated the non-woven fabric in the thickness direction through the hydrophilic region is easily transferred via the protrusions to a region that overlaps the hydrophobic region in the thickness direction of a member adjacent to the menstrual blood holding member side.

[0086] Also, for the same reason, preferably at least a part of the plurality of protrusions, and more preferably all of the plurality of protrusions (each of the plurality of protrusions) are arranged so as to further overlap, in a plan view from the thickness direction of the non-woven fabric, a hydrophilic region adjacent to one side in the second direction and a hydrophilic region adjacent to the other side in the second direction.

[0087] The nonwoven fabric according to the present disclosure can be a nonwoven fabric known in the art, and examples thereof include spunlace nonwoven fabric, needle-punched nonwoven fabric, etc. The above nonwoven fabric is preferably a spunlace nonwoven fabric. Thereby, it becomes easier to ensure the thickness of the above nonwoven fabric as compared with the nonwoven fabric having a squeezing part.

[0088] The nonwoven fabric according to the present disclosure may or may not include the above-mentioned heat-fused part where the fibers are fused with other fibers after heat shrinkage, but it is preferably not provided with the above heat-fused part. Thereby, it becomes easier to ensure the thickness of the above nonwoven fabric as compared with the nonwoven fabric having a heat-fused part.

[0089] The nonwoven fabric according to the present disclosure can contain the above-mentioned fibers after heat shrinkage (heat-fusible fibers) and hydrophilic fibers in an arbitrary mass ratio. The nonwoven fabric according to the present disclosure preferably contains the above-mentioned fibers after heat shrinkage (heat-fusible fibers) and hydrophilic fibers in a mass ratio of 40 to 90:10 to 60, more preferably 45 to 85:15 to 55, and even more preferably 50 to 80:20 to 50 with respect to a total of 100 parts by mass thereof. Thereby, when the above nonwoven fabric is used for an absorbent article, the nonwoven fabric is less likely to be colored red by menstrual blood, and the concealment of the menstrual blood that has migrated inside the absorbent article is likely to be excellent.

[0090] The above nonwoven fabric can have an arbitrary thickness, but preferably has a thickness of 0.3 mm or more, and more preferably 0.5 mm or more. Also, the above nonwoven fabric preferably has a thickness of 2.5 mm or less, and more preferably 2.0 mm or less. Thereby, when the above nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in the concealment of menstrual blood.

[0091] In this specification, the thickness of the nonwoven fabric is measured using a thickness gauge (for example, FS-60DS manufactured by Daiei Scientific Instruments Co., Ltd., measuring surface area 15 cm 2 ), and three different parts of the nonwoven fabric (when using the thickness gauge FS-60DS, the area of each part is 15 cm 2 ) are measured at a constant pressure of 3 g / cm 2Pressurize and measure the thickness 10 seconds after pressurization at each site. Conduct the same measurement for each of the 10 nonwoven fabrics, and take the average value of the total 30 measurement values as the thickness of the nonwoven fabric.

[0092] The nonwoven fabric according to the present disclosure can have an arbitrary basis weight, preferably 30 g / m 2 or more, more preferably 40 g / m 2 or more, and even more preferably 50 g / m 2 or more of the basis weight. Also, the nonwoven fabric according to the present disclosure preferably has a basis weight of 200 g / m 2 or less, more preferably 180 g / m 2 or less, and even more preferably 150 g / m 2 or less of the basis weight. Thereby, when the above nonwoven fabric is used for an absorbent article, the nonwoven fabric is excellent in concealing menstrual blood.

[0093] In the present disclosure, the basis weight of the nonwoven fabric is obtained by measuring the mass of three test pieces (10 mm × 10 mm) cut out from the nonwoven fabric with an analytical balance (for example, electronic balance HF-300 manufactured by Ken Seiko Kogyo Co., Ltd.), and calculating the mass per unit area (g / m 2 ) from the average value of the masses of the three test pieces.

[0094] In the nonwoven fabric according to the present disclosure, it is preferable that the heat shrinkage degree of the fibers after heat shrinkage in the hydrophilic region is smaller than the heat shrinkage degree of the fibers after heat shrinkage in the hydrophobic region. Also, it is preferable that the heat shrinkage degree of the fibers after heat shrinkage in the second direction in the hydrophilic region is smaller than the heat shrinkage degree of the fibers after heat shrinkage in the second direction in the hydrophobic region. Thereby, when the above nonwoven fabric is used for an absorbent article, menstrual blood is more likely to migrate into the absorbent article through the hydrophilic fibers as compared with the case where the relationship of the above heat shrinkage degree is not satisfied. As a result, when the above nonwoven fabric is used for an absorbent article, the nonwoven fabric is less likely to be colored red and is excellent in concealing menstrual blood.

[0095] In the nonwoven fabric according to the present disclosure, in the hydrophobic region, the heat shrinkage degree in the thickness direction of the fiber after heat shrinkage and the heat shrinkage degrees in the first direction and the second direction can be in an arbitrary relationship. For example, in at least a part of the hydrophobic region, the heat shrinkage degree in the thickness direction of the fiber after heat shrinkage can be lower than the heat shrinkage degrees in the first direction and the second direction. Thereby, when the nonwoven fabric is used for an absorbent article, the nonwoven fabric has relatively less heat shrinkage degree in the thickness direction and is excellent in concealability and touch compared with the case where the heat shrinkage degree has less directionality. In addition, as confirmed by the inventor of the present application, when there is no hydrophilic region, that is, in a nonwoven fabric composed only of fibers after heat shrinkage, it was found that the heat shrinkage degree has less directionality.

[0096] [Method for manufacturing nonwoven fabric] The method for manufacturing a nonwoven fabric according to the present disclosure includes the following steps. - A preparation step of preparing a laminated web in which a hydrophilic fiber sheet containing the hydrophilic fibers is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fibers (hereinafter, may be referred to as the "preparation step") - A water jet treatment step of subjecting the laminated web to water jet treatment from the hydrophilic fiber sheet side (hereinafter, may be referred to as the "water jet treatment step") - A nonwoven fabric forming step of forming the nonwoven fabric by heating the laminated web subjected to water jet treatment and heat-shrinking the heat-shrinkable fibers to form the fibers after heat shrinkage (hereinafter, may be referred to as the "nonwoven fabric forming step")

[0097] In the preparation step, a laminated web in which a hydrophilic fiber sheet containing the hydrophilic fibers is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fibers is prepared. The hydrophilic fiber sheet has a wet strength of preferably 2.0 N / 25 mm or less, more preferably 1.5 N / 25 mm or less, and even more preferably 1.0 N / 25 mm or less in any direction, particularly in both the transport direction and the direction orthogonal to the transport direction. Thereby, the nonwoven fabric according to the present disclosure can be easily formed. The lower limit of the wet strength is not particularly limited from the perspective of the water jet treatment, but from the perspective of transporting the hydrophilic fiber sheet, 0.3 N / 25 mm can be mentioned.

[0098] In this specification, the wet strength (N / 25 mm) is measured as follows. (1) Prepare a tensilon tester in a thermo-hygrostat chamber at a temperature of 25 ± 5°C and a humidity of 65 ± 5% RH, and let the sample stand for 24 hours. (2) Impregnate a sample cut to a width of 25 mm × a length of 50 mm with 50 μL of deionized water, let the sample stand for 3 minutes, and spread the deionized water over the entire sample to form a wet sample. (3) Measure the wet sample with a tensilon tester at a chuck interval of 30 mm and a tensile speed of 100 mm / min, and take the tensile force (N) per 25 mm width at the time of breakage as the wet strength (N / 25 mm). The wet strength is carried out in accordance with "Paper and Paperboard - Test Method for Wet Tensile Strength" in JIS P 8135:1998 and "Paper and Paperboard - Test Method for Tensile Properties - Part 2: Constant Rate of Elongation Method" in JIS P 8113:2006.

[0099] The hydrophilic fiber sheet can be a web, non-woven fabric, or tissue paper containing hydrophilic fibers. Thereby, the non-woven fabric according to the present disclosure can be easily formed.

[0100] In the water jet treatment step, the laminated web is water jet treated from the hydrophilic fiber sheet side. The conditions for the water jet treatment are not particularly limited as long as a non-woven fabric according to the present disclosure can be formed using a water jet device equipped with a plurality of nozzles. For example, the following conditions can be mentioned.

[0101] - Inner diameter of the nozzle: Preferably 0.03 mm or more, more preferably 0.05 mm or more Preferably 0.17 mm or less, more preferably 0.15 mm or less - Pitch of the nozzles (pitch in the direction orthogonal to the conveying direction): Preferably 0.3 mm or more, more preferably 0.4 mm or more Preferably 2.0 mm or less, more preferably 1.5 mm or less - Distance between the nozzles and the laminated web: Preferably 10 mm or more, more preferably 20 mm or more Preferably 60 mm or less, more preferably 50 mm or less - Water pressure of the nozzles: Preferably 1 MPa or more, more preferably 2 MPa or more Preferably 15 MPa or less, more preferably 13 MPa or less

[0102] The above water jet treatment can usually be carried out by arranging the above laminated web on a support. As the above support, those used as supports in the technical field can be adopted without particular limitation. For example, a mesh-shaped support member can be mentioned. The above mesh-shaped support member can be one in which thin wire-shaped support members (for example, resin wires, metal wires) are arranged in a plain weave net shape or a twill weave net shape. The opening diameter of the above mesh-shaped support member is preferably 0.2 mm or more, and more preferably 0.25 mm or more. Also, the opening diameter of the above mesh-shaped support member is preferably 0.6 mm or less, and more preferably 0.45 mm or less. Thereby, it becomes easier to form the non-woven fabric according to the present disclosure.

[0103] In the above non-woven fabric forming step, the laminated web subjected to the water jet treatment is heated, and the heat-shrinkable fibers are heat-shrunk to form the heat-shrunk fibers, thereby forming the non-woven fabric. In the above non-woven fabric forming step, it is preferable to form a non-woven fabric having a greater thickness than the laminated web subjected to the water jet treatment by heat-shrinking the heat-shrinkable fibers. Thereby, the formed non-woven fabric is excellent in concealment and feel.

[0104] In the above water jet treatment step, after allowing the hydrophilic fibers to penetrate into the heat-shrinkable fibers under the above-described water jet conditions, when the heat-shrinkable fibers are heat-shrunk in the nonwoven fabric forming step, the laminated web that has undergone the water jet treatment becomes less likely to shrink in the orthogonal direction. Therefore, in the nonwoven fabric forming step, by adjusting the conveyance speed of the laminated web that has undergone the water jet treatment (specifically, making the conveyance speed of the nonwoven fabric after heating slower than the conveyance speed of the laminated web that has undergone the water jet treatment before heating), the heat-shrinkable fibers (fibers after heat shrinkage) are likely to gather in the thickness direction, and thus it is considered that the nonwoven fabric becomes thicker than the laminated web.

[0105] Figure 2 is a diagram showing a manufacturing apparatus 101 used for manufacturing the nonwoven fabric 1 according to the first embodiment. Based on Figure 2, a method for manufacturing the nonwoven fabric 1 according to the first embodiment will be described. As shown in Figure 2, the manufacturing apparatus 101 includes a first carding machine 107 that feeds heat-shrinkable fibers 103 from a feeder to form a heat-shrinkable fiber web 105, and a second carding machine 111 that feeds hydrophilic fibers 13 from a feeder to form a hydrophilic fiber sheet 109.

[0106] In the manufacturing apparatus 101, the hydrophilic fiber sheet 109 formed by the second carding machine 111 is laminated on the heat-shrinkable fiber web 105 formed by the first carding machine 107 to form a laminated web 113.

[0107] Downstream of the first carding machine 107 and the second carding machine 111, a conveyor belt 115 and a water jet device 121 are arranged. The water jet device 121 includes a first suction drum 123 and a second suction drum 125 that rotate around an axis and suck and hold the laminated web 113 being conveyed on the outer peripheral surface, a plurality of nozzles 127 that spray water and are arranged outside the first suction drum 123 so as to sandwich the laminated web 113 therebetween, a conveyor belt 129, and a dehydrator 131. The dehydrator 131 includes a conveyor belt 131a and a plurality of suction boxes 131b.

[0108] The laminated web 113 is conveyed by a conveying belt 115, and water is sprayed from a plurality of nozzles 127 onto the laminated web 113 to form a water-jet-treated laminated web 133. In the water-jet-treated laminated web 133, among the hydrophilic fiber sheets 109, the hydrophilic fibers in the portion where water is sprayed penetrate into the heat-shrinkable fiber web 105, and the penetrated hydrophilic fibers later form a plurality of hydrophilic regions 7. Also, in the water-jet-treated laminated web 133, among the hydrophilic fiber sheets 109, the hydrophilic fibers in the portion where water is not sprayed remain as they are, and the remaining portion later forms the protruding portions 15 of the hydrophilic fiber layer 11. Note that the sprayed water and the moisture held by the water-jet-treated laminated web 133 are recovered from the first suction drum 123, the second suction drum 125, and the plurality of suction boxes 131b.

[0109] The manufacturing apparatus 101 includes a heating device 141 downstream of the dehydrator 131. The water-jet-treated laminated web 133 is heated in the heating device 141 at a predetermined heat-shrinkage temperature to thermally shrink the heat-shrinkable fibers, forming the nonwoven fabric 1, and the nonwoven fabric 1 is wound up by a winder 151.

Example

[0110] Hereinafter, the present disclosure will be described with examples, but the present disclosure is not limited to these examples. [Manufacturing Example 1] Using the manufacturing apparatus 101 described in FIG. 2, nonwoven fabric No. 1 was manufactured. The conditions are as follows. - Heat-shrinkable fiber 103: Latent crimpable fiber (side-by-side type composite fiber composed of PET and low-melting-point PET, average fiber length: 51 mm, fineness: 2.2 dtex) - Heat-shrinkable fiber web 105: Basis weight: 50 g / m 2 - Hydrophilic fiber 13: Coniferous pulp fiber - Hydrophilic fiber sheet 109: Tissue (basis weight: 20 g / m 2)

[0111] - Inner diameter of nozzle: 0.10 mm - Nozzle pitch: 1.0 mm - Distance: 50 mm - Water pressure: 7 MPa - Heat shrinkage temperature: 140 °C

[0112] The basis weight of Nonwoven Fabric No.1 was 72.4 g / m 2 and the thickness was 1.76 mm. An image of the cross-section of Nonwoven Fabric No.1 in which the hydrophilic fibers were colored with a blue dye is shown in Fig. 3. Also, an image of the second side of Nonwoven Fabric No.1 is shown in Fig. 4. Note that in Fig. 4, the hydrophilic fibers are not colored. A simple absorber was placed on the liquid-impermeable sheet, and Nonwoven Fabric No.1 was placed thereon with the first side being the skin-contact surface, thereby forming Simple Absorbent Article No.1. Note that the simple absorber was manufactured by covering an absorbent core composed of softwood pulp fibers with a basis weight of 400 g / m 2 with a core wrap composed of a tissue with a basis weight of 14 g / m 2 coated with a hot melt adhesive, and forming an embossed portion.

[0113] [Production Example 2] The hydrophilic fiber 13 was changed from "softwood pulp fiber" to 'rayon fiber (average fiber length: 40 mm, fineness: 1.7 dtex)', and the hydrophilic fiber sheet 109 was changed from "tissue" to 'web of rayon fiber (basis weight: 20 g / m 2 )'. Except for this, Nonwoven Fabric No.2 and Simple Absorbent Article No.2 were produced in the same manner as in Production Example 1. The basis weight of Nonwoven Fabric No.2 was 85.3 g / m 2 and the thickness was 1.80 mm. An image of the cross-section of Nonwoven Fabric No.2 in which the hydrophilic fibers were colored with a blue dye is shown in Fig. 5.

[0114] [Comparative Production Example 3] The hydrophilic fiber 13 was changed from "softwood pulp fiber" to 'latent crimpable fiber (side-by-side type composite fiber composed of PET and low melting point PET, average fiber length: 51 mm, fineness: 2.2 dtex)', and the hydrophilic fiber sheet 109 was changed from "tissue" to 'heat-shrinkable fiber web 105 (basis weight: 20 g / m 2 )', and except for this, nonwoven fabric No. 3 and simple absorbent article No. 3 were produced in the same manner as in Production Example 1. The basis weight of nonwoven fabric No. 3 was 71.5 g / m 2 , and the thickness was 0.82 mm.

[0115] [Comparative Production Example 4] An air-through nonwoven fabric (basis weight: 28 g / m 2 ) made of heat-sealable fibers (core: polyethylene terephthalate, sheath: polyethylene, average fiber length: 51 mm, fineness: 2.8 dtex), which is generally used as the topsheet of the absorbent article, was prepared and designated as nonwoven fabric No. 4. Also, using nonwoven fabric No. 4, a simple absorbent article No. 4 was formed in the same manner as in Production Example 1.

[0116] [Comparative Production Example 5] Except for not heat-shrinking the heat-shrinkable fiber, nonwoven fabric No. 5 and simple absorbent article No. 5 were formed in the same manner as in Production Example 1. The basis weight of nonwoven fabric No. 5 was 66.6 g / m 2 , and the thickness was 1.09 mm. An image of the cross-section of nonwoven fabric No. 5 in which the hydrophilic fiber was colored with a blue dye is shown in FIG. 6.

[0117] [Example 1] The textures of nonwoven fabrics No. 1 to No. 5 were evaluated using KES (Kawabata's Evaluation System for Fabrics) with KES-FB3-A manufactured by Kato Tech Co., Ltd. Specifically, the compression linearity: LC and the compression work amount: WC (gf·cm / cm 2 ) were measured. The results are shown in Table 1. Note that the larger the value of the compression linearity, the higher the initial elasticity, and the larger the value of the compression work amount, the easier it is to be compressed and the softer it is.

[0118] The measurement conditions for KES-FB3-A are as follows. - SENS: 2 - Speed: 0.0020 cm / second - Pressing area: 2 cm 2 - Upper limit load: 50.00 gf / cm 2 - DEFOUT: 10 mm / 10 V

[0119] [Example 2] An absorption test of menstrual blood was conducted on Simple Absorbent Articles No. 1 to No. 5. The procedure for the absorption test is as follows. [Absorption Test] (1) Using a color difference meter, measure the initial color (L * a * b * ) near the center of the simple absorbent article. (2) Prepare an acrylic plate with a size of 200 mm × 100 mm (longitudinal direction × width direction) and having a 40 mm × 10 mm (longitudinal direction × width direction) hole in the center. (3) Place the above acrylic plate on the simple absorbent article so that the center of the simple absorbent article coincides with the center of the hole in the acrylic plate.

[0120] (4) Pour 3 mL of horse blood (first time) into the central hole of the acrylic plate. (5) 30 seconds after pouring 3 mL of horse blood (first time), pour 3 mL of horse blood (second time) into the central hole of the acrylic plate. (6) 60 seconds after pouring 3 mL of horse blood (first time), remove the acrylic plate from the simple absorbent article, take a post-test photo of the simple absorbent article, and measure the post-test color (L * a * b * ) near the center of the simple absorbent article. (7) Measure the color difference (ΔE) from the initial color (L * a * b * ) and the post-test color (L * a * b * ). 90 seconds after adding 3 mL of horse blood (first time), place 10 pieces of filter paper on which the initial mass: m0 (g) has been measured, and place a 525 g weight (the bottom size is 50 mm × 35 mm) on top of the 10 pieces of filter paper.

[0121] (9) After placing the weight, remove the weight and the filter paper 1 minute later, and measure the post-test mass: m1 (g) of the 10 pieces of filter paper. (10) The rewet rate: R (mass %) is calculated by the following formula: R (mass %) = 100 × (m1 - m0) / 6 Calculate according to the formula. Note that the horse blood was assumed to have a specific gravity of 1 g / mL for simplicity. The color difference (ΔE) and rewet rate of Simple Absorbency No. 1 to No. 5 are shown in Table 1, and the post-test photos of Simple Absorbency No. 1 to No. 5 after absorbing horse blood are shown in Figures 7 to 11, respectively.

[0122]

Table 1

[0123] Nonwovens No. 1 and No. 2 are found to have higher initial elasticity and be softer compared to Nonwoven No. 4, which is an air-through nonwoven generally used as the topsheet for the liquid permeability of absorbent articles. Also, Nonwovens No. 1 and No. 2 are found to be superior in concealability and less likely to rewet back compared to Nonwoven No. 4.

Explanation of Symbols

[0124] 1 Nonwoven 3 Fiber layer after heat shrinkage 5 Fiber after heat shrinkage 7 Hydrophilic region 9 Hydrophobic region 9a One-side hydrophobic region 9b The other-side hydrophobic region 11 Hydrophilic fiber layer 13 Hydrophilic fiber 15 Protrusion D1 First direction D2 Second direction T Thickness direction S1 First surface S2 Second surface P Pitch

Claims

1. A non-woven fabric for a liquid-permeable sheet of an absorbent article that absorbs menstrual blood, comprising a post-heat-shrinkage fiber layer containing post-heat-shrinkage fibers obtained by heat-shrinking hydrophobic heat-shrinkable fibers, and having a first direction, a second direction, and a thickness direction that are orthogonal to each other, wherein the post-heat-shrinkage fiber layer has a first surface and a second surface, in the post-heat-shrinkage fiber layer, the post-heat-shrinkage fibers extend in the first direction and the second direction, the post-heat-shrinkage fiber layer includes a plurality of hydrophilic regions and a hydrophobic region, the plurality of hydrophilic regions extend continuously or intermittently in a direction along the first direction, are spaced apart in the second direction, and in each of the plurality of hydrophilic regions, hydrophilic fibers penetrate the post-heat-shrinkage fibers in the thickness direction from the first surface to the second surface, in the hydrophobic region, the post-heat-shrinkage fibers are disposed on the first surface, a non-woven fabric characterized by the above.

2. In at least a part of the plurality of hydrophilic regions, one-side hydrophobic regions that are the hydrophobic regions existing on one side in the second direction of the hydrophilic region and the other-side hydrophobic regions that are the hydrophobic regions existing on the other side in the second direction of the hydrophilic region are connected by the post-heat-shrinkage fibers that are continuously arranged between the one-side hydrophobic region and the other-side hydrophobic region. The non-woven fabric according to claim 1.

3. In the hydrophobic region, in the thickness direction, the post-heat-shrinkage fibers are disposed from the first surface to the second surface. The non-woven fabric according to claim 1.

4. The non-woven fabric further includes a hydrophilic fiber layer containing hydrophilic fibers, which is joined to the second surface of the post-heat-shrinkage fiber layer. The non-woven fabric according to claim 1.

5. The hydrophilic fiber layer includes a plurality of protruding portions that protrude in the thickness direction from the second surface of the post-heat-shrinkage fiber layer and extend in a direction along the first direction, at least a part of the plurality of protruding portions is arranged so as to overlap the hydrophobic region in a plan view from the thickness direction of the non-woven fabric, The non-woven fabric according to claim 4.

6. At least a part of the plurality of protruding portions is arranged so as to further overlap a part of the plurality of hydrophilic regions in a plan view from the thickness direction of the non-woven fabric. The non-woven fabric according to claim 5.

7. The plurality of hydrophilic regions are arranged so as to have a pitch in the second direction of 0.3 to 2.0 mm. The non-woven fabric according to claim 1.

8. The nonwoven fabric according to claim 1, wherein the nonwoven fabric is a spunlace nonwoven fabric.

9. The nonwoven fabric according to claim 1, wherein the nonwoven fabric does not have a heat-sealed portion where the fibers are heat-sealed after heat shrinkage.

10. The nonwoven fabric according to claim 1, wherein the hydrophilic fiber is a cellulose-based fiber.

11. The nonwoven fabric according to claim 1, wherein the nonwoven fabric has a thickness of 0.3 to 2.5 mm.

12. An absorbent article comprising the nonwoven fabric according to any one of claims 1 to 11 as a liquid-permeable sheet.

13. A method for manufacturing the nonwoven fabric according to any one of claims 1 to 11, A preparation step of preparing a laminated web in which a hydrophilic fiber sheet containing the hydrophilic fibers is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fibers, A water jet treatment step of subjecting the laminated web to water jet treatment from the hydrophilic fiber sheet side, A nonwoven fabric forming step of forming the nonwoven fabric by heating the water jet-treated laminated web and heat-shrinking the heat-shrinkable fibers to form the fibers after heat shrinkage, The manufacturing method including.

14. The method according to claim 13, wherein the hydrophilic fiber sheet has a wet strength of 2.0 N / 25 mm or less in any direction.

15. The method according to claim 13, wherein the hydrophilic fiber sheet is a web, nonwoven fabric or tissue paper containing the hydrophilic fibers.

16. In the water jet treatment step, while transporting the laminated web in the transport direction, a plurality of nozzles having an inner diameter of 0.03 to 0.17 mm are arranged at a pitch in the orthogonal direction orthogonal to the transport direction of 0.3 to 2.0 mm, and the water jet device is arranged so that the distance between the plurality of nozzles and the laminated web is 10 to 60 mm, and water is sprayed onto the laminated web from the plurality of nozzles at a water pressure of 1 to 15 MPa to subject the laminated web to water jet treatment. The method according to claim 13.

17. The method according to claim 13, wherein in the nonwoven fabric forming step, the nonwoven fabric having a greater thickness than the water jet-treated laminated web is formed by heat-shrinking the heat-shrinkable fibers.

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