Nonwoven fabric, absorbent article comprising said nonwoven fabric, and method for producing said nonwoven fabric

Abstract

The purpose of the present disclosure is to provide a nonwoven fabric which, when used in an absorbent article, has elasticity and a soft-touch feeling. A nonwoven fabric according to the present disclosure has the following configuration.　A nonwoven fabric (1) for an absorbent article comprises a heat-shrunken-fibers layer (3) including heat-shrunken fibers (5) obtained by heat-shrinkable fibers having undergone heat shrinking, said nonwoven fabric (1) characterized in that: in the heat-shrunken-fibers layer (3), the heat-shrunken fibers (5) extend in a first direction (Ｄ1) and a second direction (D2), a heat-shrinkable region including the heat-shrunken fibers (5) is provided, and a plurality of non-heat-shrinkable regions (7) including non-heat-shrinkable fibers (13) are provided; the plurality of non-heat-shrinkable regions (7) extend continuously in a direction parallel to the first direction (D1) and are arranged so as to be spaced apart in the second direction (D2); in at least a part of the plurality of non-heat-shrinkable regions (7), the non-heat-shrinkable fibers (13) penetrate the heat-shrunken fibers (5) in a thickness direction (T); the non-heat-shrinkable fibers (13) are not thermally fused together; and the heat-shrunken-fibers layer (3), under KES compression characteristic testing, has an LC value of at least 0.50 and a WC value of at least 1.00 (gf·cm / cm2).

Description

Nonwoven fabric, absorbent article including said nonwoven fabric, and method for manufacturing said nonwoven fabric

[0001] The present invention relates to a nonwoven fabric, an absorbent article comprising the nonwoven fabric, and a method for manufacturing the nonwoven fabric.

[0002] Nonwoven fabrics for absorbent articles that have been developed with the aim of improving tactile feel are known. For example, Patent Document 1 discloses a nonwoven fabric for absorbent articles that is an air-through nonwoven fabric, and that is made of non-stretchable fibers containing fine fibers and one or more resin components selected from the group consisting of polyethylene, polypropylene, and polyethylene terephthalate. Patent Document 1 describes that a nonwoven fabric for absorbent articles that has excellent thickness recovery after compression and good cushioning properties can be provided.

[0003] Furthermore, Patent Document 2 discloses an absorbent article that includes a liquid-permeable top sheet that forms a skin-facing surface in which heat-fusible spirally crimped fibers are fused to each other or to non-heat-fusible hydrophilic fibers, and the top sheet is formed with an uneven structure in which longitudinally extending rib-like convex and concave portions are alternately arranged in the width direction, and a lower sheet containing heat-fusible fibers on the non-skin-facing side is fused to the spirally crimped fibers of the top sheet.

[0004] JP 2021-132701 A JP 2017-104375 A

[0005] However, the nonwoven fabric of Patent Document 1, which has excellent thickness recovery when compressed, good cushioning properties, and high elasticity (i.e., the property of returning to its original shape when deformed), is hard because it is resistant to deformation when compressed, while the topsheet of Patent Document 2, which has a soft and fluffy feel, is soft because the spirally crimped fibers that make up the topsheet are fused together and easily crushed when compressed, but has low elasticity because it has a weak ability to return to its original shape from a crushed state. Furthermore, it has been difficult to realize a nonwoven fabric for absorbent articles that has both elasticity and a soft feel.

[0006] An object of the present invention is to provide a nonwoven fabric that has elasticity and a soft feel when used in an absorbent article, an absorbent article including the nonwoven fabric, and a method for producing the same.

[0007] One aspect of the present invention is a nonwoven fabric for absorbent articles, comprising a heat-shrunk fiber layer containing heat-shrunk fibers formed by heat-shrunk heat-shrinkage of heat-shrinkable fibers, and having a first direction, a second direction, and a thickness direction that are perpendicular to one another, wherein the heat-shrunk fiber layer has a first surface and a second surface, and in the heat-shrunk fiber layer, the heat-shrunk fibers extend in the first direction and the second direction, the heat-shrunk fiber layer comprises a heat-shrinkable region containing the heat-shrunk fibers and a plurality of non-heat-shrinkable regions containing non-heat-shrinkable fibers, the plurality of non-heat-shrinkable regions extending continuously or intermittently in the first direction and being spaced apart in the second direction, and in at least a part of the plurality of non-heat-shrinkable regions, the non-heat-shrinkable fibers penetrate the heat-shrunk fiber in the thickness direction from the first surface to the second surface, and the non-heat-shrinkable fibers are not heat-fused to each other, and the heat-shrunk fiber layer has an LC value of 0.50 or more and a WC value of 1.00 (gf cm / cm) in a KES compression property test. ２ ) and above, it is a nonwoven fabric.

[0008] According to the present invention, it is possible to provide a nonwoven fabric that has elasticity and a soft feel when used in an absorbent article, an absorbent article including the nonwoven fabric, and a method for manufacturing the absorbent article.

[0009] Fig. 1 is a diagram for explaining a nonwoven fabric 1 according to a first embodiment. Fig. 2 is a diagram showing a manufacturing apparatus 101 for manufacturing the nonwoven fabric 1 according to the first embodiment. Fig. 3 is a diagram for explaining an example. Fig. 4 is a diagram for explaining an example. Fig. 5 is a diagram for explaining an example. Fig. 6 is a diagram for explaining an example.

[0010] Specifically, the present disclosure relates to the following aspects: [Aspect 1] A nonwoven fabric for absorbent articles, comprising a heat-shrunk fiber layer containing heat-shrunk fibers formed by heat-shrunk heat-shrinkage of heat-shrinkable fibers, and having a first direction, a second direction, and a thickness direction perpendicular to one another, wherein the heat-shrunk fiber layer has a first surface and a second surface, the heat-shrunk fibers extend in the first direction and the second direction in the heat-shrunk fiber layer, the heat-shrunk fiber layer comprises a heat-shrinkable region containing the heat-shrunk fibers and a plurality of non-heat-shrinkable regions containing non-heat-shrinkable fibers, the plurality of non-heat-shrinkable regions extend continuously or intermittently in the first direction and are spaced apart in the second direction, in at least a portion of the plurality of non-heat-shrinkable regions, the non-heat-shrinkable fibers penetrate the heat-shrunk fibers in the thickness direction from the first surface to the second surface, and the non-heat-shrinkable fibers are not heat-fused to each other, The heat-shrunk fiber layer has an LC value of 0.50 or more and a WC value of 1.00 (gf cm / cm) in a KES compression property test. ２ ) or more, nonwoven fabric.

[0011] In the nonwoven fabric, a plurality of non-heat-shrinkable regions are arranged in the planar direction in the heat-shrinkable region of the heat-shrunk fiber layer, and non-heat-shrinkable fibers penetrate in the thickness direction, so that the heat-shrunk fibers and non-heat-shrinkable fibers are present in the planar direction and thickness direction of the heat-shrunk fiber layer.

[0012] When pressure is applied to the heat-shrunk fiber layer in an uncompressed state, the heat-shrinkable region containing the crimped heat-shrunk fibers is unlikely to deform, but the non-heat-shrinkable region containing the non-heat-shrinkable fibers that are not crimped and are not heat-fused to each other is easily deformed. Therefore, the heat-shrunk fiber layer exhibits softness because the non-heat-shrinkable region causes deformation when it comes into contact with the skin.

[0013] When the pressure is removed from the compressed state of the heat-shrunk fiber layer, the non-heat-shrinkable regions containing the non-heat-shrinkable fibers that are not crimped tend to return to their original shape, but the heat-shrinkable regions containing the crimped heat-shrunk fibers tend to return to their original shape from the collapsed state. Therefore, the heat-shrunk fiber layer exhibits elasticity because it tends to return to its original shape from the deformation caused by the heat-shrinkable regions when it comes into contact with the skin.

[0014] Furthermore, the nonwoven fabric having the heat-shrunk fiber layer has elasticity when the LC value, which is a linearity value of the compression characteristic indicating elasticity, is equal to or greater than the lower limit in the KES compression property test, and has softness when the WC value, which is a value of the compression work load indicating softness, is equal to or greater than the lower limit. Therefore, the nonwoven fabric can have elasticity and a soft feel.

[0015] [Aspect 2] The heat-shrunk fiber layer has an LC value of 1.00 or less and a WC value of 4.50 (gf cm / cm ２ 2. The nonwoven fabric of claim 1, wherein:

[0016] The nonwoven fabric has the same effects as those of the first embodiment.

[0017] [Embodiment 3] The nonwoven fabric according to embodiment 1 or 2, wherein the heat-shrunk fibers in the heat-shrunk fiber layer are entangled with each other without being thermally fused.

[0018] The nonwoven fabric has excellent feel to the touch because the fibers are entangled without forming the specified heat-sealed portions after heat shrinkage, making it easier to ensure the thickness of the heat-shrinkable region than nonwoven fabrics with heat-sealed regions.

[0019] [Embodiment 4] The nonwoven fabric according to any one of embodiments 1 to 3, wherein the nonwoven fabric is a spunlace nonwoven fabric.

[0020] The nonwoven fabric described above has an excellent feel to the touch because it is easier to ensure the thickness of the non-heat-shrinkable region than a nonwoven fabric having a compressed region.

[0021] [Aspect 5] An absorbent article comprising the nonwoven fabric according to any one of aspects 1 to 4.

[0022] In the absorbent article, the same effects as those of any one of the first to fourth aspects can be obtained.

[0023] Aspect 6 is a method for producing the nonwoven fabric according to any one of Aspects 1 to 4, comprising: a preparation step of preparing a laminated web in which a non-heat-shrinkable fiber sheet containing the non-heat-shrinkable fiber is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fiber; a water-jet processing step of water-jetting the laminated web from the non-heat-shrinkable fiber sheet side; and a nonwoven fabric forming step of heating the water-jet-processed laminated web to heat-shrink the heat-shrinkable fiber and form the heat-shrunk fiber, thereby forming the nonwoven fabric.

[0024] The above-mentioned production method can easily produce the nonwoven fabric according to any one of Aspects 1 to 4.

[0025] [Aspect 7] The method according to aspect 6, wherein the non-heat-shrinkable fiber sheet has a wet strength of 2.0 N / 25 mm or less in any direction.

[0026] In the above-described production method, the nonwoven fabric according to any one of Aspects 1 to 4 can be easily produced because the non-heat-shrinkable fiber sheet has a predetermined wet strength.

[0027] [Embodiment 8] The method according to embodiment 6 or 7, wherein the non-heat-shrinkable fiber sheet is a web, nonwoven fabric, or tissue paper containing the non-heat-shrinkable fiber.

[0028] In the above-described manufacturing method, the nonwoven fabric according to any one of the first to fourth aspects can be easily manufactured since the non-heat-shrinkable fiber sheet is made of a predetermined material.

[0029] Aspect 9: The manufacturing method of any one of Aspects 6 to 8, wherein in the water jet treatment step, while the laminate web is transported in a transport direction, a water jet device having a plurality of nozzles with an inner diameter of 0.03 to 0.17 mm arranged at a pitch of 0.3 to 2.0 mm in a direction perpendicular to the transport direction is disposed so that the distance between the plurality of nozzles and the laminate web is 10 to 60 mm, and water is sprayed from the plurality of nozzles onto the laminate web at a water pressure of 1 to 15 MPa, thereby water jetting the laminate web.

[0030] In the above-described manufacturing method, the laminated web is subjected to water jet processing under predetermined conditions, and therefore the nonwoven fabric according to any one of Aspects 1 to 4 can be easily manufactured.

[0031] [Aspect 10] The manufacturing method according to any one of Aspects 6 to 9, wherein in the nonwoven fabric forming step, the heat-shrinkable fiber is heat-shrunk to form the nonwoven fabric having a thickness greater than that of the water-jet-treated laminated web.

[0032] In the above-described production method, a nonwoven fabric having a predetermined thickness is formed by heat-shrinking the heat-shrinkable fiber, and therefore the nonwoven fabric according to any one of Aspects 1 to 4 can be easily produced.

[0033] The nonwoven fabric for an absorbent article according to the present disclosure, the absorbent article including the nonwoven fabric, and the method for manufacturing the nonwoven fabric will be described in detail below. The absorbent article will be described together with the nonwoven fabric.

[0034] The nonwoven fabric according to the present disclosure is a nonwoven fabric for absorbent articles. In this specification, the "nonwoven fabric for absorbent articles" may be simply referred to as the "nonwoven fabric."

[0035] [Nonwoven Fabric] Fig. 1 is a diagram illustrating a nonwoven fabric 1 according to one embodiment of the present disclosure (hereinafter referred to as "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 absorbent articles. The nonwoven fabric 1 has a first direction D perpendicular to each other. １ , second direction D ２ and a thickness direction T. The nonwoven fabric 1 includes a heat-shrunk fiber layer 3 containing heat-shrunk fibers 5 formed by heat-shrunk heat-shrinkable fibers. Specifically, the heat-shrinkable fibers are latently crimpable fibers, and the heat-shrunk fibers 5 are crimped latently crimpable fibers.

[0036] The heat-shrunk fiber layer 3 has a first surface S which constitutes the skin contact surface when used in an absorbent article. １ and the first surface S １ and the second surface S on the opposite side ２In the heat-shrunk fiber layer 3, the heat-shrunk fibers 5 are crimped in the first direction D １ and the second direction D ２ It extends to.

[0037] The heat-shrunk fiber layer 3 is divided into a non-heat-shrinkable region 7 and a heat-shrinkable region 9. The heat-shrunk fiber layer 3 includes the heat-shrinkable region 9 containing the heat-shrunk fiber 5 and a plurality of non-heat-shrinkable regions 7 containing the non-heat-shrinkable fiber 13. The plurality of non-heat-shrinkable regions 7 are arranged in a first direction D. １ and extends continuously in parallel with the second direction D ２ In at least some of the non-heat-shrinkable regions 7, the non-heat-shrinkable fibers 13 are arranged to separate the fibers 5 from the first surface S after heat shrinkage. １ From the second surface S ２ The non-heat-shrinkable fibers 13 penetrate in the thickness direction T to the end of the heat-shrinkable fiber layer 3. In the heat-shrinkable fiber layer 3, the non-heat-shrinkable fibers 13 are not thermally fused together and are included in the non-heat-shrinkable region 7.

[0038] In addition, in a KES (Kawabata's Evaluation System for Fabrics) compression property test, the heat-shrunk fiber layer 3 has an LC value, which is a value of linearity of compression property (compression linearity) indicating the height of initial elasticity (resilience), of 0.50 or more, and a WC value, which is a value of compression work load indicating softness, of 1.00 (gf cm / cm ２ ) That's all.

[0039] In Fig. 1, the non-heat-shrinkable fiber 13 is shown thicker than the heat-shrunk fiber 5 to make the invention easier to understand, but this does not mean the relationship between the actual fiber diameters of the non-heat-shrinkable fiber 13 and the heat-shrunk fiber 5. The same applies to the fiber lengths of the non-heat-shrinkable fiber 13 and the heat-shrunk fiber 5. The protruding ridge portions 15 made of the non-heat-shrinkable fiber 13 also do not mean the relationship between the actual length (thickness) in the thickness direction T and the heat-shrunk fiber layer 3. In Fig. 1, the heat-shrunk fiber 5 is shown spirally, but this does not mean the crimp state, orientation, etc. of the actual heat-shrunk fiber.

[0040] In the nonwoven fabric 1, the heat-shrunk fibers 5 and the non-heat-shrinkable fibers 13 are present in the planar direction and thickness direction T of the heat-shrunk fiber layer 3. Therefore, when pressure is applied to the heat-shrunk fiber layer 3 in an uncompressed state, the non-heat-shrinkable regions 7 containing the non-heat-shrinkable fibers 13 that are uncrimped and not thermally bonded to each other are easily deformed. That is, deformation occurs when the heat-shrunk fiber layer 3 comes into contact with the skin, thereby exhibiting softness. Furthermore, when pressure is removed from the compressed state of the heat-shrunk fiber layer 3, the heat-shrinkable regions 9 containing the crimped heat-shrunk fibers 5 attempt to return to their original shape from their collapsed state. That is, they attempt to return to their original shape from the deformation caused by contact with the skin, thereby exhibiting elasticity.

[0041] The feel (texture) of the nonwoven fabric 1 can be expressed numerically by carrying out a KES compression property test. In the KES compression property test, the nonwoven fabric 1 including the heat-shrunk fiber layer 3 has an LC value of 0.50 or more, which indicates elasticity, and a WC value of 1.00 (gf cm / cm ２ ) or more, it has a soft feel.

[0042] In each of the plurality of non-heat-shrinkable regions 7, the second direction D of the non-heat-shrinkable region 7 ２ a heat-shrinkable region 9a that is a heat-shrinkable region 9 that is present in one of the first and second directions D ２ The other heat-shrinkable region 9 b, which is the heat-shrinkable region 9 located on the other side of the first heat-shrinkable region 9, is connected to the other heat-shrinkable region 9 b by the continuous heat-shrinkable fibers 5. In other words, each of the plurality of non-heat-shrinkable regions 7 is connected to the other heat-shrinkable region 9 b in the first direction D. １ and does not have a fracture surface that penetrates in the thickness direction T and breaks the fibers 5 after heat shrinkage. As a result, when the nonwoven fabric 1 is used in an absorbent article, the nonwoven fabric 1 exhibits softness because it deforms when it comes into contact with the skin, and also exhibits elasticity because it tries to return to its original shape after deformation.

[0043] The nonwoven fabric 1 is a second surface S of the fiber layer 3 after heat shrinkage. ２ The heat-shrunk fiber layer 3 further includes a group of protrusions 11 including non-heat-shrinkable fibers 13 bonded to the second surface S of the heat-shrunk fiber layer 3. Specifically, the group of protrusions 11 is made of non-heat-shrinkable fibers 13 and is bonded to the second surface S of the heat-shrunk fiber layer 3. ２from the first direction D １ Each of the plurality of protrusions 15 overlaps with the heat-shrinkable region 9 in a plan view from the thickness direction T of the nonwoven fabric 1, and extends parallel to the second direction D of the heat-shrinkable region 9. ２ The non-heat-shrinkable region 7 is arranged so as to overlap with two adjacent non-heat-shrinkable regions 7 .

[0044] The nonwoven fabric according to the present disclosure is a nonwoven fabric for use in absorbent articles. The absorbent article, including the nonwoven fabric, absorbs liquids. Examples of the liquids include bodily fluids such as menstrual blood, blood (e.g., plasma, blood cells), vaginal discharge, breast milk, urine, nasal discharge, and saliva. The absorbent article is not particularly limited as long as it has a liquid-retaining member that absorbs liquids, such as an absorbent core. Examples of the absorbent article include sanitary napkins, sanitary shorts, tampons, bedsore pads, adhesive bandages, food packaging sheets, panty liners, breast pads, disposable diapers, incontinence pads, urine absorption sheets, disposable pants, and masks.

[0045] The nonwoven fabric according to the present disclosure has a first direction, a second direction, and a thickness direction that are perpendicular to each other. Examples of the first direction and the second direction include the conveying direction during manufacturing and the orthogonal direction perpendicular to the conveying direction, respectively. In this specification, the direction including the first direction and the second direction may be referred to as the planar direction.

[0046] The nonwoven fabric according to the present disclosure includes a heat-shrunk fiber layer containing heat-shrunk fibers formed by heat-shrunk heat-shrinkable fibers. The heat-shrunk fiber layer has 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 and fibers whose apparent fiber length is shortened by heat treatment (e.g., latently crimpable fibers whose apparent fiber length is shortened by crimping). Examples of the latently crimpable fibers include composite fibers containing two thermoplastic resins with different shrinkage rates, such as eccentric core-sheath composite fibers and side-by-side composite fibers.

[0047] Examples of the composite fibers include eccentric sheath-core composite fibers having a core made of polyethylene terephthalate resin and a sheath made of polyethylene resin; eccentric sheath-core composite fibers having a core made of polypropylene resin and a sheath made of polyethylene resin; eccentric sheath-core composite fibers having a core made of high-melting-point polypropylene resin and a sheath made of low-melting-point polypropylene resin; side-by-side composite fibers made of polyethylene terephthalate resin (PET) and low-melting-point polyethylene terephthalate resin; side-by-side composite fibers made of polyethylene terephthalate resin and polyethylene resin; and side-by-side composite fibers made of polypropylene resin and polyethylene resin.

[0048] The heat-shrinkable fibers preferably have an average fiber length of 20 mm or more, more preferably 30 mm or more. The heat-shrinkable fibers preferably have an average fiber length of 70 mm or less, more preferably 60 mm or less. This provides excellent formability for the nonwoven fabric according to the present disclosure.

[0049] The heat-shrinkable fiber preferably has a fineness of 0.5 dtex or more, and more preferably 1.0 dtex or more. The heat-shrinkable fiber preferably has a fineness of 8.0 dtex or less, and more preferably 7.0 dtex or less. This makes it easier to ensure a consistent thickness of the nonwoven fabric according to the present disclosure, resulting in an excellent feel against the skin. Furthermore, since a consistent number of heat-shrinkable fibers can be ensured, the nonwoven fabric tends to return to its original shape when pressure is removed from a compressed state, providing elasticity.

[0050] In the heat-shrunk fiber layer of the nonwoven fabric according to the present disclosure, the heat-shrunk fibers extend in a first direction and a second direction. The heat-shrunk fiber layer includes a plurality of non-heat-shrinkable regions and a single or multiple heat-shrinkable regions. The heat-shrunk fiber layer may be partitioned into a plurality of non-heat-shrinkable regions and a single or multiple heat-shrinkable regions.

[0051] The non-heat-shrinkable regions extend continuously or intermittently in a plane direction parallel to the first direction and are spaced apart in a second direction. In the thickness direction, in each of the non-heat-shrinkable regions, the non-heat-shrinkable fiber penetrates the heat-shrunk fiber in the thickness direction from the first surface to the second surface. This allows the heat-shrunk fiber and the non-heat-shrinkable fiber to exist in the plane direction and thickness direction of the heat-shrunk fiber layer. In the present disclosure, "a direction parallel to the first direction" means a direction that crosses the first direction at an angle of preferably less than 45°, more preferably 30° or less, even more preferably 20° or less, and even more preferably 5° or less.

[0052] When pressure is applied to the heat-shrunk fiber layer from an uncompressed state, the heat-shrinkable region containing the crimped heat-shrunk fibers is unlikely to deform, but the non-heat-shrinkable region containing the non-heat-shrinkable fibers that are not crimped and are not heat-fused to each other is easily deformed. Therefore, the heat-shrunk fiber layer exhibits softness because the non-heat-shrinkable region, which easily deforms in response to pressure, deforms when it comes into contact with the skin.

[0053] The nonwoven fabric in which the heat-shrunk fiber layer comprises a plurality of non-heat-shrinkable regions and a single heat-shrinkable region includes a nonwoven fabric in which each of the plurality of non-heat-shrinkable regions extends intermittently in the first direction, in other words, a nonwoven fabric in which a single heat-shrinkable region includes a plurality of non-heat-shrinkable regions that extend intermittently in the first direction and are spaced apart in the first and second directions.

[0054] The non-heat-shrinkable fibers may be fibers known in the art that do not or hardly crimp upon heat treatment. Examples of the non-heat-shrinkable fibers include hydrophilic fibers. Examples of the hydrophilic fibers include absorbent fibers, such as cellulosic fibers, and non-absorbent fibers, such as synthetic fibers that have been hydrophilized. Examples of the cellulosic fibers include natural cellulose fibers, regenerated cellulose fibers, refined 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), vein fibers (e.g., Manila hemp), and fruit fibers (e.g., palm).

[0055] The pulp fibers include those known in the art, such as 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, reed pulp fibers, kenaf pulp fibers, mulberry pulp fibers, bamboo pulp fibers, hemp pulp fibers, and cotton pulp fibers (e.g., cotton linter fibers). The pulp fibers may be waste paper, recycled pulp fibers, etc.

[0056] The cotton fiber includes Hirsutum cotton fiber (e.g., upland cotton), Barbadense cotton fiber, Arboreum cotton fiber, and Helbaceum cotton fiber. The cotton fiber may also be organic cotton fiber or Pre-Organic Cotton (trademark) fiber. Organic cotton fiber refers to cotton certified by GOTS (Global Organic Textile Standard).

[0057] Examples of the regenerated cellulose fibers include rayon, for example, viscose rayon obtained from viscose, polynosic and modal, and cuprammonium rayon (also called "cupra") obtained from a cuprammonium salt solution of cellulose.

[0058] The purified cellulose fiber includes lyocell, specifically, a fiber obtained by dissolving pulp in an aqueous solution of N-methylmorpholine N-oxide to form a spinning dope (dope) and extruding the dope into a dilute solution of N-methylmorpholine N-oxide. The purified cellulose is commercially available, for example, under the trade name Tencel (trademark). The semi-synthetic fiber includes semi-synthetic cellulose, such as acetate fibers, e.g., triacetate and diacetate fibers.

[0059] The hydrophilically treated synthetic fibers include those commonly used in the art, such as those containing a single component, e.g., a single fiber, or those containing multiple components, e.g., a composite fiber. The synthetic fibers may also be biomass plastics, recycled materials, etc.

[0060] Examples of the above 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.

[0061] The synthetic fibers are preferably biodegradable, which makes the nonwoven fabric more biodegradable. Examples of components of the biodegradable synthetic fibers 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, polylactic acid, polyhydroxybutyrate, polyglycolic acid, and cellulose acetate.

[0062] In this specification, the average fiber length of fibers including heat-shrinkable fibers and non-heat-shrinkable fibers (excluding pulp fibers) is measured in accordance with "A7.1.1 Method A (standard method) - measuring the length of individual fibers on a graduated glass plate" in "A7.1 Measurement of fiber length" of Annex A of JIS L 1015:2010. Note that this method is a test method equivalent to ISO 6989 published in 1981.

[0063] As used herein, the average fiber length of pulp fibers refers to the weight-weighted average fiber length, and refers to the L(w) value measured by Kajaani FiberLab fiber properties (off-line) manufactured by Metso Automation.

[0064] The heat-shrunk fiber layer preferably has the heat-shrunk fibers on at least a first surface thereof, and the heat-shrunk fibers are preferably arranged from the first surface to the second surface thereof in the thickness direction thereof, so that when the nonwoven fabric is used in an absorbent article, the heat-shrinkable region of the nonwoven fabric has elasticity because it contains the crimped fibers (heat-shrunk fibers).

[0065] In the nonwoven fabric according to the present disclosure, preferably in at least a portion of the plurality of non-heat-shrinkable regions, and more preferably in all of the plurality of non-heat-shrinkable regions, a one-side heat-shrinkable region, which is a heat-shrinkable region located on one side of the non-heat-shrinkable region in the second direction, and a other-side heat-shrinkable region, which is a heat-shrinkable region located on the other side of the non-heat-shrinkable region in the second direction, are connected by heat-shrunk fibers that are continuously arranged between the one-side heat-shrinkable region and the other-side heat-shrinkable region.

[0066] The compression properties of the nonwoven fabric according to the present disclosure can be evaluated in accordance with the KES using a KES-FB3-A manufactured by Kato Tech Co., Ltd. Specifically, the compression linearity (LC) and compression work (WC) (gf cm / cm ２ ) can be measured. A larger value of compression linearity means higher initial elasticity (more resilience), and a larger value of compression work means that the nonwoven fabric is easier to compress and softer. Therefore, the feel (handiness) of the nonwoven fabric can be evaluated numerically.

[0067] The measurement conditions for KES-FB3-A are as follows: SENS: 2 Speed: 0.0020 cm / sec Pressurized area: 2 cm ２ - Upper limit load: 50.00gf / cm ２ -DEFOUT: 10mm / 10V

[0068] The LC value of the heat-shrunk fiber layer of the nonwoven fabric according to the present disclosure is preferably 0.50 or more, more preferably 0.53 or more, and even more preferably 0.56 or more. This provides elasticity to the nonwoven fabric according to the present disclosure. The LC value is also preferably 1.00 or less, more preferably 0.85 or less, and even more preferably 0.70 or less. This allows the nonwoven fabric according to the present disclosure to be moderately prone to compressive deformation. Therefore, when the LC value is within the above preferred range, the nonwoven fabric according to the present disclosure is prone to have elasticity and a soft feel.

[0069] The WC value of the fiber layer after heat shrinkage of the nonwoven fabric according to the present disclosure is preferably 1.00 (gf cm / cm ２ ) or more, more preferably 1.03 (gf cm / cm ２) or more, and more preferably 1.06 (gf cm / cm ２ ) or more. As a result, the nonwoven fabric according to the present disclosure has a soft feel. In addition, the WC value is preferably 4.50 (gf cm / cm ２ ) or less, more preferably 3.00 (gf cm / cm ２ ) or less, and more preferably 1.50 (gf cm / cm ２ ) or less. This makes the nonwoven fabric according to the present disclosure suitably resistant to crushing. Therefore, when the WC value of the nonwoven fabric according to the present disclosure is in the above-mentioned preferred range, it tends to have a soft feel and elasticity.

[0070] In the nonwoven fabric according to the present disclosure, in the KES compression property test, the LC value of the fiber layer after heat shrinkage is 0.50 or more and the WC value is 1.00 (gf cm / cm ２ ) or more, it is possible to achieve both elasticity (high initial elasticity) and a soft feel.

[0071] The nonwoven fabric according to the present disclosure can be a nonwoven fabric known in the art, such as a spunlace nonwoven fabric or a needle-punched nonwoven fabric. The nonwoven fabric is preferably a spunlace nonwoven fabric. This makes it easier to ensure the thickness of the nonwoven fabric compared to a nonwoven fabric with compressed sections. Furthermore, since a larger number of non-heat-shrinkable fibers penetrate the heat-shrinkable fibers in the thickness direction, the nonwoven fabric exhibits softness and an excellent feel against the skin.

[0072] The nonwoven fabric according to the present disclosure may or may not have the heat-sealed portions in which the heat-shrunk fibers are fused to other fibers, but it is preferable that the nonwoven fabric does not have the heat-sealed portions. This makes it easier to ensure the thickness of the nonwoven fabric compared to a nonwoven fabric that has heat-sealed portions. Furthermore, the nonwoven fabric according to the present disclosure is preferably such that the heat-shrunk fibers are entangled without forming the heat-sealed portions (non-heat-fused). This makes it easier to ensure the thickness of the heat-shrinkable region compared to a nonwoven fabric that has heat-sealed portions in which the heat-shrunk fibers are entangled without forming the required heat-sealed portions, resulting in an excellent feel to the skin.

[0073] In this specification, the thickness of the nonwoven fabric is measured using a thickness meter (for example, FS-60DS manufactured by Daiei Scientific Instruments Co., Ltd., measuring probe area 15 cm ２ ) to measure the area of ​​three different nonwoven fabrics (when using a thickness gauge FS-60DS, the area of ​​each part is 15 cm ２ ) at a constant pressure of 3 g / cm ２ A pressure is applied at a pressure of 100 psi, and the thickness at each site is measured 10 seconds after the pressure is applied. The same measurement is carried out for each of the 10 nonwoven fabrics, and the average value of the 30 measured values ​​in total is taken as the thickness of the nonwoven fabric.

[0074] The nonwoven fabric according to the present disclosure can have any basis weight, but preferably has a basis weight of 30 g / m ２ More preferably, 40 g / m ２ More preferably, 50 g / m ２ The nonwoven fabric according to the present disclosure preferably has a basis weight of 200 g / m or more. ２ or less, more preferably 180 g / m ２ or less, and more preferably 150 g / m ２ It has the following basis weight:

[0075] In the present disclosure, the basis weight of a nonwoven fabric is determined by measuring the mass of three test pieces (10 mm × 10 mm) cut out from the nonwoven fabric using a direct reading balance (for example, an electronic balance HF-300 manufactured by Kensei Kogyo Co., Ltd.), and calculating the average mass of the three test pieces as the mass per unit area (g / m ２ ) means

[0076] In the nonwoven fabric according to the present disclosure, the heat-shrinkable fiber has a higher degree of heat shrinkage than the non-heat-shrinkable fiber. The degree of heat shrinkage indicates the degree of heat shrinkage of the fiber, and heat shrinkage is the change in the actual fiber length and apparent fiber length of the fiber due to heat treatment. The heat-shrinkable fiber is crimped by heat treatment, shortening the actual fiber length or apparent fiber length. The non-heat-shrinkable fiber does not crimp by heat treatment, or even if it crimps, the actual fiber length and apparent fiber length are not shorter than the crimp of the heat-shrinkable fiber.

[0077] In the nonwoven fabric according to the present disclosure, the heat shrinkage of the heat-shrunk fiber in the non-heat-shrinkable region is preferably smaller than the heat shrinkage of the heat-shrunk fiber in the heat-shrinkable region. Furthermore, the heat shrinkage of the heat-shrunk fiber in the second direction in the non-heat-shrinkable region is preferably smaller than the heat shrinkage of the heat-shrunk fiber in the second direction in the heat-shrinkable region. This allows the nonwoven fabric, when used in an absorbent article, to more easily deform when in contact with the skin, compared to when the above heat shrinkage relationship is not satisfied, resulting in a softer feel to the nonwoven fabric.

[0078] In the nonwoven fabric according to the present disclosure, in the heat-shrinkable region, the heat shrinkage degree in the thickness direction of the heat-shrunk fiber and the heat shrinkage degree in the first and second directions can have any relationship, but for example, in at least a portion of the heat-shrinkable region, the heat shrinkage degree in the thickness direction of the heat-shrunk fiber can be lower than the heat shrinkage degree in the first and second directions. As a result, when the nonwoven fabric is used in an absorbent article, the heat shrinkage degree in the thickness direction of the nonwoven fabric is relatively low compared to when the heat shrinkage degree is less directional, and the feel is excellent. Note that, according to confirmation by the present inventors, when a nonwoven fabric does not have a non-heat-shrinkable region, i.e., when composed only of the heat-shrunk fiber, the heat shrinkage degree is less directional.

[0079] When the non-heat-shrinkable fiber is a hydrophilic fiber, the nonwoven fabric according to the present disclosure has excellent concealing properties for absorbed body fluids such as menstrual blood. That is, the nonwoven fabric according to the present disclosure can be used as a liquid-permeable sheet for an absorbent article, etc., as a nonwoven fabric having the following characteristics:

[0080] When the non-heat-shrinkable fiber is a hydrophilic fiber, the heat-shrunk fiber layer includes a plurality of hydrophilic regions containing hydrophilic fibers and a heat-shrinkable region containing heat-shrunk fibers. In the heat-shrunk fiber layer, the plurality of hydrophilic regions extend continuously or intermittently and are spaced apart in the second direction. In each of the plurality of hydrophilic regions, the hydrophilic fiber penetrates the heat-shrunk fiber arranged on the first surface in the thickness direction.

[0081] As a result, body fluids that reach the first surface of the heat-shrunk fiber layer are less likely to remain in the heat-shrinkable region containing the heat-shrunk fibers and less likely to penetrate into the heat-shrinkable region, and are more likely to migrate into the absorbent article through the hydrophilic region that penetrates from the first surface to the second surface in the thickness direction. Therefore, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric is less likely to be discolored by body fluids. Specifically, the nonwoven fabric is less likely to be discolored by red body fluids such as menstrual blood, and is also less likely to be discolored by non-red body fluids such as urine and vaginal discharge.

[0082] After the body fluid has migrated into the absorbent article, the heat-shrinkable region of the nonwoven fabric contains post-heat-shrunk fibers, making it difficult for visible light to pass through, and thus making it difficult for the body fluid that has migrated into the absorbent article to be visually recognized. Furthermore, because the heat-shrinkable region of the nonwoven fabric contains post-heat-shrunk fibers, it is physically difficult for the body fluid that has migrated into the absorbent article to pass through (rewetback is unlikely to occur).

[0083] Since the post-heat-shrinkage fibers extend in the first and second directions in the hydrophilic regions as well, when the nonwoven fabric is used in an absorbent article, the hydrophilic regions are less likely to open even when a force such as body pressure is applied, making it difficult to see the body fluids held by the hydrophilic fibers and absorbed into the absorbent article from the outside of the absorbent article. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric is less likely to be discolored by body fluids and has excellent concealing properties for body fluids such as menstrual blood that have migrated into the absorbent article. Specifically, the nonwoven fabric is less likely to be discolored by red body fluids such as menstrual blood and other body fluids, and is less likely to be discolored by non-red body fluids such as urine and vaginal discharge, and has excellent concealing properties for body fluids such as menstrual blood that have migrated into the absorbent article.

[0084] In at least a portion of the plurality of hydrophilic regions, it is preferable that a one-side heat-shrinkable region, which is the heat-shrinkable region located on one side of the second direction of the hydrophilic region, and a second-side heat-shrinkable region, which is the heat-shrinkable region located on the other side of the second direction of the hydrophilic region, are connected by the heat-shrunk fiber that is continuously arranged between the one-side heat-shrinkable region and the second-side heat-shrinkable region.

[0085] As a result, in the nonwoven fabric, at least some of the multiple hydrophilic regions are connected by heat-shrunk fibers that are continuously arranged from one heat-shrinkable region to the other heat-shrinkable region, so when the nonwoven fabric is used in an absorbent article, even when a force such as body pressure is applied, the hydrophilic regions are less likely to open, and body fluids held by the hydrophilic fibers and absorbed into the absorbent article are less likely to be visible from the outside of the absorbent article. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent ability to conceal body fluids that have migrated into the absorbent article.

[0086] In the heat-shrinkable region, it is preferable that the heat-shrunk fibers are arranged from the first surface to the second surface in the thickness direction. As a result, when the nonwoven fabric is used in an absorbent article, the heat-shrinkable region is less likely to transmit visible light, making it difficult to visually recognize body fluid that has migrated into the absorbent article. Furthermore, because the heat-shrinkable region of the nonwoven fabric contains the heat-shrunk fibers, it is physically less likely to transmit body fluid that has migrated into the absorbent article (rewetback is less likely to occur).

[0087] The nonwoven fabric preferably further includes a hydrophilic fiber layer containing hydrophilic fibers bonded to the second surface of the heat-shrunk fiber layer. When the nonwoven fabric is used in an absorbent article, the hydrophilic fiber layer can diffuse body fluid that has permeated the nonwoven fabric (liquid-permeable sheet) in the planar direction and easily transfer the body fluid to a member adjacent to the body fluid retention member (e.g., absorbent body) that retains the body fluid. The body fluid retention member is a liquid retention member that can retain at least body fluid such as menstrual blood. As a result, the body fluid is easily diffused from the excretory opening contact area in the first and second directions and transferred to a member adjacent to the body fluid retention member. Consequently, the redness of the body fluid retention member due to menstrual blood or blood is less likely to be partially darkened. Similarly, the color of the body fluid retention member due to urine or vaginal discharge is less likely to be partially darkened. Therefore, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent body fluid concealment properties.

[0088] The hydrophilic fiber layer preferably includes a plurality of protrusions protruding from the second surface of the heat-shrunk fiber layer in the thickness direction and extending in the first direction, and at least some of the protrusions are preferably arranged so as to overlap the heat-shrinkable regions when viewed from above in the thickness direction of the nonwoven fabric. This facilitates transfer of body fluid that passes through the hydrophilic regions and penetrates the nonwoven fabric in the thickness direction to a component adjacent to the body fluid retention member via the protrusions. Furthermore, the protrusions arranged so as to overlap the heat-shrinkable regions facilitate transfer of body fluid to a region of the component adjacent to the body fluid retention member that overlaps the heat-shrinkable region in the thickness direction. As a result, the color of the body fluid retention member is less likely to become partially dark, such as red. Therefore, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent body fluid concealment properties.

[0089] It is preferable that at least some of the protrusions are arranged so as to overlap portions of the hydrophilic regions in a plan view of the nonwoven fabric in the thickness direction. This makes it easier for bodily fluid that has passed through the hydrophilic regions and penetrated the nonwoven fabric to migrate via the protrusions to regions of the member adjacent to the bodily fluid retention member that overlap with the heat-shrinkable regions in the thickness direction. As a result, the color of the bodily fluid retention member, such as red, is less likely to become darker in parts. Therefore, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent bodily fluid concealment properties.

[0090] The plurality of hydrophilic regions are preferably arranged at a pitch of 0.3 to 2.0 mm in the second direction. This allows bodily fluid to easily pass through the hydrophilic regions to a member adjacent to the bodily fluid retention member when the nonwoven fabric is used in an absorbent article, and reduces the likelihood of bodily fluid remaining on the first surface of the heat-shrinkable region. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent bodily fluid concealment properties.

[0091] The nonwoven fabric is preferably a spunlace nonwoven fabric. Because the nonwoven fabric is a spunlace nonwoven fabric, it is easier to ensure the thickness of the nonwoven fabric compared to nonwoven fabrics with compressed portions. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent hiding properties for body fluids.

[0092] The nonwoven fabric preferably does not have a heat-sealed portion where the fibers are heat-sealed after heat shrinkage. This makes it easier to ensure the thickness of the nonwoven fabric compared to a nonwoven fabric that has a heat-sealed portion. As a result, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent body fluid concealment properties.

[0093] In the nonwoven fabric, the hydrophilic fibers are preferably cellulosic fibers. When the nonwoven fabric is used in an absorbent article, the hydrophilic fibers facilitate the drawing of body fluids into the absorbent article through the hydrophilic regions. As a result, body fluids are less likely to remain on the first surface of the heat-shrinkable region. Consequently, when the nonwoven fabric is used in an absorbent article, the nonwoven fabric has excellent body fluid concealment properties.

[0094] The nonwoven fabric preferably has a thickness of 0.3 to 2.5 mm. By having the predetermined thickness, the nonwoven fabric has excellent body fluid hiding properties when used in absorbent articles.

[0095] [Method for manufacturing nonwoven fabric] The method for manufacturing nonwoven fabric according to the present disclosure includes the following steps: - a preparation step (hereinafter may be referred to as the "preparation step") of preparing a laminated web in which a non-heat-shrinkable fiber sheet containing the non-heat-shrinkable fiber is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fiber; - a water jet treatment step (hereinafter may be referred to as the "water jet treatment step") of water jetting the laminated web from the non-heat-shrinkable fiber sheet side; - a nonwoven fabric formation step (hereinafter may be referred to as the "nonwoven fabric formation step") of heating the water-jet-treated laminated web and heat-shrinking the heat-shrinkable fiber to form the heat-shrunk fiber, thereby forming the nonwoven fabric.

[0096] In the preparation step, a laminated web is prepared in which a non-heat-shrinkable fiber sheet containing the non-heat-shrinkable fiber is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fiber. The non-heat-shrinkable 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 conveying direction and the direction perpendicular to the conveying direction. This allows the nonwoven fabric according to the present disclosure to be easily formed. Note that there is no particular lower limit for the wet strength from the viewpoint of water jet processing, but from the viewpoint of conveying the non-heat-shrinkable fiber sheet, a lower limit of 0.3 N / 25 mm is an example.

[0097] In this specification, wet strength (N / 25 mm) is measured as follows: (1) A Tensilon tester is prepared in a constant temperature and humidity chamber at a temperature of 25±5°C and a humidity of 65±5% RH, and a sample is left standing for 24 hours. (2) A sample cut to a width of 25 mm and a length of 50 mm is impregnated with 50 μL of deionized water and left standing for 3 minutes to allow the deionized water to spread throughout the sample, forming a wet sample. (3) The wet sample is measured using the Tensilon tester with a chuck spacing of 30 mm and a tensile speed of 100 mm / min, and the tensile force (N) per 25 mm of width at break is defined as the wet strength (N / 25 mm). The wet strength is measured in accordance with JIS P 8135:1998 "Paper and paperboard -- Testing method for wet tensile strength" and JIS P 8113:2006 "Paper and paperboard -- Testing methods for tensile properties -- Part 2: Constant rate of extension method."

[0098] The non-heat-shrinkable fiber sheet may be a web, nonwoven fabric, or tissue paper containing non-heat-shrinkable fibers, which allows the nonwoven fabric according to the present disclosure to be easily formed.

[0099] In the water jet treatment step, the laminated web is water jet treated from the non-heat-shrinkable fiber sheet side. The conditions for the water jet treatment are not particularly limited as long as the nonwoven fabric according to the present disclosure can be formed using a water jet device equipped with multiple nozzles. For example, the following conditions can be mentioned:

[0100] - Inner diameter of nozzle: preferably 0.03 mm or more, more preferably 0.05 mm or more and preferably 0.17 mm or less, more preferably 0.15 mm or less - Nozzle pitch (pitch in a direction perpendicular to the conveying direction): preferably 0.3 mm or more, more preferably 0.4 mm or more and preferably 2.0 mm or less, more preferably 1.5 mm or less - Distance between nozzle and laminated web: preferably 10 mm or more, more preferably 20 mm or more and preferably 60 mm or less, more preferably 50 mm or less - Nozzle water pressure: preferably 1 MPa or more, more preferably 2 MPa or more and preferably 15 MPa or less, more preferably 13 MPa or less

[0101] The water jet treatment is typically performed by placing the laminate web on a support. The support can be any support commonly used in the art, and examples include mesh-like support members. The mesh-like support member can be a plain-woven or twill-woven mesh of thin wire-like support members (e.g., resin wires, metal wires). The opening diameter of the mesh-like support member is preferably 0.2 mm or more, and more preferably 0.25 mm or more. The opening diameter of the mesh-like support member is preferably 0.6 mm or less, and more preferably 0.45 mm or less. This facilitates the formation of the nonwoven fabric according to the present disclosure.

[0102] In the nonwoven fabric forming step, the water-jet-treated laminated web is heated to heat-shrink the heat-shrinkable fibers to form the heat-shrunk fibers, thereby forming the nonwoven fabric. In the nonwoven fabric forming step, it is preferable that the heat-shrinkable fibers are heat-shrunk to form a nonwoven fabric that is thicker than the water-jet-treated laminated web. This results in a nonwoven fabric that is soft to the touch.

[0103]

[0033] Note that if the non-heat-shrinkable fiber is made to penetrate the heat-shrinkable fiber under the water jet conditions in the water jet treatment step, and then the heat-shrinkable fiber is heat-shrunk in the nonwoven fabric formation step, the water-jet-treated laminated web will be less likely to heat shrink in the orthogonal direction. Therefore, if the conveying speed of the water-jet-treated laminated web is adjusted in the nonwoven fabric formation step (specifically, if the conveying speed of the nonwoven fabric after heating is made slower than the conveying speed of the water-jet-treated laminated web before heating), the heat-shrinkable fiber (fiber after heat shrinkage) will be more likely to gather in the thickness direction, and the nonwoven fabric will be thicker than the laminated web.

[0104] Figure 2 is a diagram showing a manufacturing apparatus 101 used to manufacture the nonwoven fabric 1 according to the first embodiment. A method for manufacturing the nonwoven fabric 1 according to the first embodiment will be described with reference to Figure 2. As shown in Figure 2, the manufacturing apparatus 101 includes a first carding machine 107 that inputs heat-shrinkable fibers 103 from a feeder to form a heat-shrinkable fiber web 105, and a second carding machine 111 that inputs non-heat-shrinkable fibers 13 from a feeder to form a non-heat-shrinkable fiber sheet 109.

[0105] In the manufacturing apparatus 101, a non-heat-shrinkable fiber sheet 109 formed by a second carding machine 111 is laminated on a heat-shrinkable fiber web 105 formed by a first carding machine 107 to form a laminated web 113.

[0106] A conveyor belt 115 and a water jet device 121 are disposed downstream of the first carding machine 107 and the second carding machine 111. The water jet device 121 includes a first suction drum 123 and a second suction drum 125 that rotate about their axes to suck and hold the transported laminated web 113 against their outer circumferential surfaces, a plurality of nozzles 127 that spray water and are disposed outside the first suction drum 123 so as to sandwich the laminated web 113 therebetween, a conveyor belt 129, and a dewatering machine 131. The dewatering machine 131 includes a conveyor belt 131a and a plurality of suction boxes 131b.

[0107] The laminate web 113 is transported on a conveyor belt 115, and water is sprayed onto the laminate web 113 from multiple nozzles 127 to form a water-jet-treated laminate web 133. In the water-jet-treated laminate web 133, the non-heat-shrinkable fibers in the non-heat-shrinkable fiber sheet 109 in the areas where water is sprayed penetrate into the heat-shrinkable fiber web 105, and these penetrated non-heat-shrinkable fibers will later form multiple non-heat-shrinkable regions 7. In the water-jet-treated laminate web 133, the non-heat-shrinkable fibers in the non-heat-shrinkable fiber sheet 109 in the areas where water is not sprayed remain, and these remaining portions will later form the protrusions 15 that make up the protrusion group 11. If the remaining portions are layered, the protrusion group 11 will form a non-heat-shrinkable fiber layer. The sprayed water and moisture retained in the water-jet-treated laminate web 133 are recovered from the first suction drum 123, the second suction drum 125, and the multiple suction boxes 131b.

[0108] The manufacturing apparatus 101 is equipped with 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, causing the heat-shrinkable fibers to heat shrink, forming a nonwoven fabric 1, which is then wound up by a winder 151.

[0109] The present disclosure will be described below using examples, but the present disclosure is not limited to these examples. [Production Example 1] Nonwoven fabric No. 1 was produced using the production apparatus 101 shown in Figure 2. The conditions were as follows: Heat-shrinkable fiber 103: Potentially crimpable fiber (side-by-side composite fiber made 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 - Non-heat-shrinkable fiber 13: softwood pulp fiber - Non-heat-shrinkable fiber sheet 109: tissue (basis weight: 20 g / m ２ )

[0110] - Nozzle inner diameter: 0.10 mm - Nozzle pitch: 1.0 mm - Distance: 50 mm - Water pressure: 7 MPa - Heat shrinkage temperature: 140°C

[0111] The basis weight of Nonwoven Fabric No. 1 is 72.4 g / m ２ The thickness was 1.76 mm. Figure 3 shows an image of the cross section of nonwoven fabric No. 1, in which the non-heat-shrinkable fiber was colored with a blue dye. Figure 4 shows an image of the second surface of nonwoven fabric No. 1. Note that in Figure 4, the non-heat-shrinkable fiber was not colored.

[0112] [Manufacturing Example 2] The non-heat-shrinkable fiber 13 was changed from "softwood pulp fiber" to "rayon fiber (average fiber length: 40 mm, fineness: 1.7 dtex)", and the non-heat-shrinkable fiber sheet 109 was changed from "tissue" to "rayon fiber web (basis weight: 20 g / m ２ Nonwoven fabric No. 2 was produced in the same manner as in Production Example 1, except that the thickness of the nonwoven fabric No. 2 was changed to "1000 mm." The basis weight of nonwoven fabric No. 2 was 85.3 g / m. ２ The thickness was 1.80 mm. Figure 5 shows an image of the cross section of nonwoven fabric No. 2, in which the non-heat-shrinkable fiber was colored with a blue dye.

[0113] Comparative Manufacturing Example 3 The non-heat-shrinkable fiber 13 was changed from "softwood pulp fiber" to "latently crimpable fiber (side-by-side composite fiber made of PET and low-melting point PET, average fiber length: 51 mm, fineness: 2.2 dtex)", and the non-heat-shrinkable fiber sheet 109 was changed from "tissue" to "heat-shrinkable fiber web 105 (basis weight: 20 g / m ２Nonwoven fabric No. 3 was produced in the same manner as in Production Example 1, except that the thickness of the nonwoven fabric No. 3 was changed to "1.5 g / m²." The basis weight of nonwoven fabric No. 3 was 71.5 g / m². ２ and the thickness was 0.82 mm.

[0114] Comparative Production Example 4 An air-through nonwoven fabric (basis weight: 28 g / m) made of heat-fusible fibers (core: polyethylene terephthalate, sheath: polyethylene, average fiber length: 51 mm, fineness: 2.8 dtex) which is generally used as a liquid-permeable top sheet of an absorbent article was prepared. ２ ) was prepared and designated as nonwoven fabric No. 4.

[0115] Comparative Production Example 5 Nonwoven fabric No. 5 was produced in the same manner as Production Example 1, except that the heat-shrinkable fiber was not heat-shrunk. The basis weight of nonwoven fabric No. 5 was 66.6 g / m ２ The thickness was 1.09 mm. Figure 6 shows an image of the cross section of nonwoven fabric No. 5, in which the non-heat-shrinkable fiber was colored with a blue dye.

[0116] [Example 1] The feel of nonwoven fabrics No. 1 to No. 5 was evaluated by measuring the LC value and WC value in accordance with the KES standard using a KES-FB3-A manufactured by Kato Tech Co., Ltd. The results are shown in Table 1.

[0117]

[0118] It can be seen that Nonwoven Fabrics No. 1 and No. 2 have higher initial elasticity and softer properties than Nonwoven Fabric No. 4, an air-through nonwoven fabric commonly used as a liquid-permeable topsheet in absorbent articles.

[0119] Nonwoven fabrics No. 3 and No. 5 were produced by the same production method as Nonwoven fabrics No. 1 and No. 2, but their thicknesses were less than 70% of those of Nonwoven fabrics No. 1 and No. 2. Nonwoven fabric No. 3 was a nonwoven fabric that did not contain non-heat-shrinkable fibers, and Nonwoven fabric No. 5 was a nonwoven fabric that did not contain fibers after heat shrinkage.

[0120] Comparing Nonwoven Fabrics No. 1 and No. 2 with Nonwoven Fabric No. 3, it is believed that a nonwoven fabric in which non-heat-shrinkable fibers penetrate through heat-shrunk fibers can ensure a greater thickness than a nonwoven fabric in which heat-shrunk fibers penetrate through heat-shrunk fibers. Also, comparing Nonwoven Fabrics No. 1 and No. 2 with Nonwoven Fabric No. 5, it is believed that a nonwoven fabric in which non-heat-shrinkable fibers penetrate through heat-shrunk fibers can ensure a greater thickness than a nonwoven fabric in which non-heat-shrinkable fibers penetrate through non-heat-shrinkable fibers.

[0121] Therefore, it is considered that nonwoven fabrics No. 1 and No. 2 can easily ensure thickness by having a plurality of non-heat-shrinkable regions arranged in the planar direction within the heat-shrinkable region and a heat-shrunk fiber layer through which non-heat-shrinkable fibers penetrate in the thickness direction. Furthermore, nonwoven fabrics No. 1 and No. 2, which are composed of a heat-shrunk fiber layer, have an LC value of 0.50 or more and a WC value of 1.00 (gf cm / cm) in the KES compression property test, compared to nonwoven fabrics No. 3 to No. 5. ２ ) or more, which shows that both elasticity (high initial elasticity) and soft touch are achieved.

[0122] That is, the nonwoven fabric of the present disclosure can be said to have a sufficient thickness and elasticity and a soft feel due to the heat-shrunk fiber layer in which the heat-shrunk fibers and non-heat-shrinkable fibers are present in the planar direction and thickness direction of the heat-shrunk fiber layer.

[0123] REFERENCE SIGNS LIST 1 Nonwoven fabric 3 Heat-shrunk fiber layer 5 Heat-shrunk fiber 7 Non-heat-shrinkable region 9 Heat-shrinkable region 9a One-side heat-shrinkable region 9b Other-side heat-shrinkable region 11 Group of protrusions 13 Non-heat-shrinkable fiber 15 Protrusion D １ First direction D ２ Second direction T Thickness direction S １ 1st page S ２ Second surface P pitch

Claims

1. A nonwoven fabric for absorbent articles, comprising a heat-shrunk fiber layer containing heat-shrunk fibers formed by heat shrinking of heat-shrinkable fibers, and having a first direction, a second direction and a thickness direction which are perpendicular to one another, wherein the heat-shrunk fiber layer has a first surface and a second surface, the heat-shrunk fibers extend in the first direction and the second direction in the heat-shrunk fiber layer, the heat-shrunk fiber layer comprises a heat-shrinkable region containing the heat-shrunk fibers and a plurality of non-heat-shrinkable regions containing non-heat-shrinkable fibers, the plurality of non-heat-shrinkable regions extend continuously or intermittently in the first direction and are spaced apart in the second direction, and in at least a portion of the plurality of non-heat-shrinkable regions, the non-heat-shrinkable fibers penetrate the heat-shrunk fibers in the thickness direction from the first surface to the second surface, and the non-heat-shrinkable fibers are not heat-fused together, The heat-shrunk fiber layer has an LC value of 0.50 or more and a WC value of 1.00 (gf cm / cm) in a KES compression property test. ２ ) or more, nonwoven fabric.

2. The fiber layer after heat shrinkage has an LC value of 1.00 or less and a WC value of 4.50 (gf cm / cm ２ 2. The nonwoven fabric of claim 1, wherein the tensile strength is 100% or less.

3. The nonwoven fabric according to claim 1 or 2, wherein the heat-shrunk fibers in the heat-shrunk fiber layer are entangled with each other without being thermally fused.

4. The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric is a spunlace nonwoven fabric.

5. An absorbent article comprising the nonwoven fabric according to any one of claims 1 to 4.

6. A method for producing a nonwoven fabric according to any one of claims 1 to 4, comprising: a preparation step of preparing a laminated web in which a non-heat-shrinkable fiber sheet containing the non-heat-shrinkable fiber is laminated on a heat-shrinkable fiber web containing the heat-shrinkable fiber; a water-jet processing step of water-jetting the laminated web from the non-heat-shrinkable fiber sheet side; and a nonwoven fabric formation step of heating the water-jet-processed laminated web and heat-shrinking the heat-shrinkable fiber to form the heat-shrunk fiber, thereby forming the nonwoven fabric.

7. The manufacturing method according to claim 6, wherein the non-heat-shrinkable fiber sheet has a wet strength of 2.0 N / 25 mm or less in any direction.

8. The manufacturing method according to claim 6 or 7, wherein the non-heat-shrinkable fiber sheet is a web, nonwoven fabric or tissue paper containing the non-heat-shrinkable fiber.

9. A manufacturing method according to any one of claims 6 to 8, wherein in the water jet treatment step, while the laminate web is transported in a transport direction, a water jet device having a plurality of nozzles with an inner diameter of 0.03 to 0.17 mm arranged at a pitch of 0.3 to 2.0 mm in a direction perpendicular to the transport direction is arranged so that the distance between the plurality of nozzles and the laminate web is 10 to 60 mm, and water is sprayed from the plurality of nozzles onto the laminate web at a water pressure of 1 to 15 MPa, thereby water jet treating the laminate web.

10. The manufacturing method according to any one of claims 6 to 9, wherein in the nonwoven fabric forming step, the heat-shrinkable fiber is heat-shrunk to form the nonwoven fabric having a thickness greater than that of the water-jet-treated laminated web.

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