Irregular nonwoven fabric manufacturing method and manufacturing device

Abstract

To provide a technique capable of efficiently manufacturing an irregular nonwoven fabric containing cellulose fibers and having excellent three-dimensional feeling.SOLUTION: An irregular nonwoven fabric manufacturing method of the invention injects water flow to a web 11 in a state in which the web 11 containing cellulose fibers is placed on an irregular surface 20a of an irregular support 20 having the irregular surface 20a on which a plurality of protrusions 22 are formed. The irregular support 20 has a base plate 21 forming a surface on which the web 11 of the irregular support 20 is placed, the plurality of protrusions 22 disposed on a surface corresponding to the irregular surface 20a on the base plate 21, and a plurality of open holes 23 penetrating the base plate 21 in a thickness direction. The protrusions 22 and the open holes 23 are scattered on the irregular surface 20a. Open hole area on the irregular surface 20a side of the open hole 23 is 3.5 mm2 or more and 20 mm2 or less. Thickness T of a formation site of the open hole 23 on the base plate 21 is 2.5 mm or more.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a manufacturing technique for a rugged nonwoven fabric containing cellulose fibers. [Background technology]

[0002] Spunlace nonwoven fabrics are produced by a process in which a water flow is sprayed onto a web, which is a fiber assembly, to entangle the fibers contained in the web. Spunlace nonwoven fabrics are superior in flexibility, texture, etc. compared to other nonwoven fabrics, and taking advantage of these characteristics, they are used as components of sanitary products such as disposable diapers and sanitary napkins (for example, Patent Document 1).

[0003] Patent Document 2 describes a manufacturing apparatus for a spunlace nonwoven fabric having an opening, which includes a conveyer belt for conveying a web and a support placed on the conveyer belt, and is configured to spray a water flow onto the web while conveying the web with the conveyer belt in a state where the web is placed on the support. The support described in Patent Document 2 has a plurality of pyramid-shaped protrusions arranged on the web placement surface, and a plurality of holes arranged around the protrusions and penetrating the support in the thickness direction. In the embodiment, the aperture of the hole is 0.025 inches (0.064 cm) to 0.038 inches (0.1 cm). As shown in FIG. 1 of Patent Document 2, the spunlace nonwoven fabric manufactured by the apparatus described in Patent Document 2 has relatively large openings at positions corresponding to the protrusions of the support during manufacturing, and is substantially flat with little unevenness overall, and is difficult to call an uneven nonwoven fabric.

[0004] Patent Document 3 describes a method for producing a concave-convex nonwoven fabric, which includes a step of forming a concave-convex shape on a web by blowing hot air onto the web while the web is placed on a support. The support described in Patent Document 3 has a plurality of protrusions arranged on the web placement surface and a plurality of through holes penetrating the support in the thickness direction, and the protrusions and the through holes are arranged alternately in a predetermined direction. The web used in the production method described in Patent Document 3 is mainly made of thermoplastic fibers (synthetic fibers), and Patent Document 3 does not describe a method for producing a concave-convex nonwoven fabric using a web containing cellulose fibers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 004369 [Patent Document 2] Special Publication No. 8-502100 [Patent Document 3] JP 2012-149370 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, thermoplastic fibers made from thermoplastic resins such as polyethylene have been widely used as raw fibers for nonwoven fabrics, but in recent years, cellulose fibers such as cotton fibers have been attracting attention in nonwoven fabrics for absorbent articles such as disposable diapers and sanitary napkins, sanitary products such as cosmetic sheets and masks, and daily necessities such as cleaning wipes. By using cellulose fibers as raw fibers for nonwoven fabrics, in addition to improving the quality of the nonwoven fabric, such as the feel of use, it is expected to reduce the burden on the environment, and further, it is expected to improve the product image, which is associated with the use of natural fibers instead of synthetic fibers such as thermoplastic fibers. However, because cellulose fibers have poor thermoplasticity, it is difficult to form three-dimensional shapes such as unevenness and open holes in conventional nonwoven fabrics using cellulose fibers, and they have poor three-dimensionality compared to nonwoven fabrics using thermoplastic fibers.

[0007] An object of the present invention is to provide a technique capable of efficiently producing a concave-convex nonwoven fabric that contains cellulose fibers and has excellent three-dimensional appearance. [Means for solving the problem]

[0008] The present invention is a method for producing a concavo-convex nonwoven fabric that contains cellulose fibers and has a plurality of convex portions intermittently arranged on at least one surface. In one embodiment of the method for producing a textured nonwoven fabric of the present invention, it is preferable to include a water jet spraying step in which a web containing cellulose fibers is placed on the textured surface of a textured support having a textured surface on which a plurality of protrusions are formed, and a water jet is sprayed over the entire area of ​​the web to entangle the fibers contained in the web and form the protrusions on the web. In one embodiment of the manufacturing method for the uneven nonwoven fabric of the present invention, the uneven support has a base plate that forms the surface of the uneven support on which the web is placed, a plurality of protrusions arranged on a surface of the base plate corresponding to the uneven surface, and a plurality of through holes that penetrate the base plate in the thickness direction, and it is preferable that the protrusions and the through holes are scattered on the uneven surface. In one embodiment of the method for producing the uneven nonwoven fabric of the present invention, the opening area of ​​the through-holes on the uneven surface side is 3.5 mm 2 More than 20mm 2 It is preferable that: In one embodiment of the method for producing a concave-convex nonwoven fabric of the present invention, it is preferable that the thickness of the base plate at the location where the through holes are formed is 2.5 mm or more.

[0009] The present invention also relates to an apparatus for producing a concave-convex nonwoven fabric that contains cellulose fibers and has a plurality of convex portions intermittently arranged on at least one surface. In one embodiment of the apparatus for producing the uneven nonwoven fabric of the present invention, it is preferable to include a hydroentanglement device that subjects a web containing cellulose fibers to a hydroentanglement treatment. In one embodiment of the apparatus for manufacturing the uneven nonwoven fabric of the present invention, it is preferable that the hydroentanglement device comprises a conveying mechanism for conveying the web, an uneven support on which the web is placed while being conveyed by the conveying mechanism, and a water flow nozzle for spraying a water flow onto the web placed on the uneven support. In one embodiment of the uneven nonwoven fabric manufacturing apparatus of the present invention, the uneven support body has a base plate having an uneven surface on which a plurality of protrusions are formed, and a plurality of through holes penetrating the base plate in the thickness direction, and it is preferable that the protrusions and the through holes are scattered on the surface of the base plate on which the web is placed. In one embodiment of the apparatus for producing a nonwoven fabric of the present invention, the opening area of ​​the through-holes on the side of the uneven surface is 3.5 mm 2 More than 20mm 2 It is preferable that: In one embodiment of the apparatus for producing a concave-convex nonwoven fabric of the present invention, it is preferable that the thickness of the base plate at the location where the through holes are formed is 2.5 mm or more. Other features, advantages and embodiments of the present invention are described below. Effect of the Invention

[0010] According to the present invention, a concave-convex nonwoven fabric containing cellulose fibers and having excellent three-dimensional appearance can be efficiently produced. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view of the first surface side of one embodiment of a concavo-convex nonwoven fabric produced by the present invention. [Diagram 2] FIG. 2 is a cross-sectional view that diagrammatically shows a cross section taken along line AA in FIG. 1 (a cross section along the vertical direction CD and the thickness direction). [Diagram 3] FIG. 3 is a schematic diagram of a main part (hydroentangling device) of one embodiment of the manufacturing device for the uneven nonwoven fabric of the present invention. [Figure 4] FIG. 4 is a schematic perspective view of the concave-convex surface (surface on which the web is placed) of the concave-convex support body shown in FIG. [Diagram 5]Figure 5(a) is a schematic plan view of the uneven surface (the surface on which the web is placed) of the uneven support shown in Figure 4, Figure 5(b) is a cross-sectional view showing a schematic cross-section along line BB (cross-section along the machine direction MD and thickness direction) of Figure 5(a), and Figure 5(c) is a cross-sectional view showing a schematic cross-section along line CC (cross-section along the vertical direction CD and thickness direction) of Figure 5(a). [Figure 6] 6(a) to 6(c) are schematic views showing one embodiment of a water jetting step using the device shown in FIG. 3, and are cross-sectional views along the machine direction and thickness direction of the concave-convex support body. [Figure 7] FIG. 7 is a perspective view showing an enlarged schematic view of a part of the concave-convex surface (the surface on which the web is placed) of another embodiment of the concave-convex support according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described below based on preferred embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

[0013] First, the uneven nonwoven fabric produced by the manufacturing method or manufacturing device of the present invention will be described. Figures 1 and 2 show an uneven nonwoven fabric 1, which is one embodiment of the uneven nonwoven fabric. The uneven nonwoven fabric 1 contains cellulose fibers, and has a plurality of convex portions 2 intermittently arranged on at least one surface 1a.

[0014] The uneven nonwoven fabric 1 has a first surface 1a and a second surface 1b located on the opposite side thereof, and a plurality of protrusions 2 are intermittently arranged on at least the first surface 1a. On the first surface 1a, recesses 3 exist between adjacent protrusions 2, 2. The recesses 3 are spaces defined by a plurality of protrusions 2 and a fiber layer (a low basis weight portion 6 described later) connecting the plurality of protrusions 2, and the fiber layer forms the bottom of the recesses 3.

[0015] The first surface 1a is an uneven surface having an uneven shape formed by protrusions 2 and recesses 3. On the other hand, the second surface 1b is substantially flat. The term "substantially flat" as used herein includes a flat surface without any irregularities and a surface having minute irregularities that are clearly smaller than those of the first surface 1a. In the latter surface, minute depressions (not shown) may be present in the areas of the second surface 1b that overlap the protrusions 2 in plan view (the surface of the high basis weight portion 5 on the second surface 1b side, which will be described later). The minute depressions typically do not have a constant depression depth, but have a maximum depth at the center of the protrusions 2 in plan view, and have a relatively gentle arc-shaped contour line with the area having the maximum depth as the bottom.

[0016] The inside of the protrusions 2 is filled with fibers and has a solid structure. Because the protrusions 2 have a solid structure, the uneven nonwoven fabric 1 having the protrusions 2 has excellent cushioning properties.

[0017] In the illustrated embodiment, the uneven nonwoven fabric 1 has a plurality of openings 4 penetrating the uneven nonwoven fabric 1 in the thickness direction. The openings 4 are areas where the constituent fibers of the uneven nonwoven fabric 1 are not present, and are formed at the bottoms of the recesses 3. In the uneven nonwoven fabric 1, as shown in FIG. 1, on the first surface 1a, the protrusions 2 and the openings 4 are alternately arranged in a direction X and also alternately arranged in a direction Y perpendicular to the direction X.

[0018] Direction X corresponds to the machine direction (MD) during production of the uneven nonwoven fabric 1, i.e., the running direction of the uneven nonwoven fabric 1 or its raw material or intermediate product (e.g., a web), and direction Y corresponds to the vertical direction (CD; Cross machine direction) perpendicular to the MD.

[0019] The opening area of ​​the openings 4 on the first surface 1a side (the surface on which the convex portions are arranged) is not particularly limited, but from the viewpoint of the balance between the effects that can be achieved by the openings 4 (such as the effect of improving breathability and liquid permeability) and ensuring sufficient strength for practical use, it is preferably 1 mm 2 More than 2mm, preferably 2 More than 5mm, preferably2 Less than 4mm, more preferably 2 The following is the result.

[0020] The three-dimensional shape of the uneven nonwoven fabric is formed by spraying a water stream onto a web (a fiber aggregate with no inter-fiber bonding) which is a precursor of the uneven nonwoven fabric in a water stream spraying step in the manufacturing method of the uneven nonwoven fabric of the present invention described later, and rearranging and reentangling the constituent fibers of the web. The three-dimensional shape is configured to include at least the bottoms of the convex portions 2 and the concave portions 3, and further includes the open holes 4 in the illustrated embodiment. The micro-depressions which may be present on the second surface 1b of the uneven nonwoven fabric 1 are also included in the three-dimensional shape. For example, in the water stream spraying step in the manufacturing method of the uneven nonwoven fabric 1 in the illustrated embodiment, typically, the fibers at the bottoms of the concave portions 3 and the portions where the open holes 4 are to be formed in the web are moved by the water stream to the portions where the convex portions 2 are to be formed, and as a result, the bottoms of the concave portions 3 or the open holes 4 are formed at the origin of the fibers, and the convex portions 2 are formed at the destination of the fibers. In the water jetting step, for example, with the web 11 placed on the first surface 20a, which is the uneven surface of the uneven support 20 shown in Fig. 4, a water jet is sprayed from the first surface 20a toward the second surface 20b of the uneven support 20, that is, from the surface side corresponding to the second surface 1b of the web 11 placed on the uneven support 20 toward the surface side corresponding to the first surface 1a, thereby rearranging and reentangling the constituent fibers of the web 11 (see Fig. 6). The convex portions 2, the bottoms of the concave portions 3, and the openings 4 formed by such rearrangement and reentanglement of the fibers can each maintain their shape by themselves.

[0021] The uneven nonwoven fabric 1 has non-uniform fiber basis weights, with high basis weight sections 5 having a relatively large basis weight and low basis weight sections 6 having a relatively small basis weight. In the illustrated embodiment, it further has open sections 4 having a basis weight of zero. The protrusions 2 are the portions of the high basis weight sections 5 that exist on the first surface 1a of the uneven nonwoven fabric 1 (portions that protrude from the surface of the first surface 1a), and the bottoms of the recesses 3 are made up of the low basis weight sections 6. Note that the uneven nonwoven fabric 1 is typically made up only of fibers, in which case the "basis weight of the nonwoven fabric" is the same as the "basis weight of the fibers that constitute the nonwoven fabric".

[0022] The basis weight of the uneven nonwoven fabric 1 is not particularly limited, but from the viewpoint of the balance of various properties such as appearance, strength, cushioning properties, and portability in the form of a product such as an absorbent article, it is preferably 15 g / m 2 More preferably, 25 g / m 2 More than 100 g / m 2 Less than 80 g / m 2 The following is the result. The basis weight of the high basis weight portion 5 is preferably 30 g / m2, provided that the basis weight is greater than the basis weight of the low basis weight portion 6. 2 More preferably, 50 g / m 2 More than 110 g / m 2 Less than 90g / m 2 The following is the result. The basis weight of the low basis weight portion 6 is preferably 10 g / m 2 on the assumption that it is smaller than the basis weight of the high basis weight portion 5. 2 More preferably, 15 g / m 2 More than 40 g / m 2 Less than or equal to 35 g / m 2 The following is the result.

[0023] In the illustrated embodiment, each of the plurality of protrusions 2 is dome-shaped and has a circular shape in a plan view of the first surface 1a. In the present invention, the shape of the protrusions 2 is not particularly limited, and any shape may be selected. In addition, the shapes of the plurality of protrusions 2 may be different from each other. In the illustrated embodiment, each of the multiple openings 4 has an elliptical shape that is long in one direction (direction X) in a plan view. In the present invention, the shape of the openings 4 is not particularly limited, and any shape may be selected. Furthermore, the multiple openings 4 may have different shapes. Furthermore, although the illustrated uneven nonwoven fabric 1 has a single layer structure, the uneven nonwoven fabric of the present invention may have a layered structure in which two or more fiber layers are layered in the thickness direction.

[0024] The uneven nonwoven fabric produced by the present invention contains cellulose fibers. As the cellulose fibers, any fiber that can be used for this type of nonwoven fabric product can be used without any particular limitation. Examples of the cellulose fibers include natural cellulose fibers such as cotton fibers harvested from cotton plants, regenerated cellulose fibers such as rayon, cupra, lyocell, and tencel, and pulp. Among these cellulose fibers, cotton fibers, rayon, lyocell, and tencel are preferred, and cotton fibers are more preferred from the viewpoint of improving liquid absorption. The uneven nonwoven fabric produced by the present invention may contain two or more types of cellulose fibers.

[0025] In the uneven nonwoven fabric produced by the present invention, the content of cellulose fibers is not particularly limited, but from the viewpoint of more reliably achieving the effects of containing cellulose fibers (improved quality, reduced environmental impact, etc.), the content is preferably 30 mass% or more, more preferably 60 mass% or more, relative to the total mass of the uneven nonwoven fabric, and it may even be 100 mass%, i.e., the entire uneven nonwoven fabric is cellulose fiber.

[0026] The uneven nonwoven fabric produced by the present invention may contain fibers other than cellulose fibers. In this case, the distribution form of the other fibers in the uneven nonwoven fabric is not particularly limited, and for example, the other fibers may be uniformly distributed throughout the uneven nonwoven fabric together with the cellulose fibers, or may be unevenly distributed. A specific example of the latter is a form in which the uneven nonwoven fabric has a first layer mainly composed of cellulose fibers and a second layer containing other fibers (e.g., thermoplastic fibers), and both layers are laminated in the thickness direction.

[0027] An example of the other fibers is a thermoplastic fiber mainly made of a thermoplastic resin. By incorporating thermoplastic fibers into the uneven nonwoven fabric, it is expected that the strength of the fabric can be improved. Examples of the thermoplastic resin include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polymethacrylic acid alkyl esters, polyvinyl chloride, and polyvinylidene chloride. The thermoplastic fiber may be a single fiber made of one type of thermoplastic resin or a blend polymer made by mixing two or more types of thermoplastic resins, or may be a composite fiber. A composite fiber is typically obtained by combining two or more types of thermoplastic resins with different components in a spinneret and spinning them simultaneously, and each of the multiple components has a structure that is continuous in the length direction of the fiber and is mutually bonded within the single fiber. The form of the composite fiber includes a core-sheath type, a side-by-side type, and the like, and is not particularly limited. The content of thermoplastic fibers in the uneven nonwoven fabric produced by the present invention is preferably 15 mass% or more, more preferably 20 mass% or more, and preferably 75 mass% or less, more preferably 50 mass% or less, and even more preferably 35 mass% or less, relative to the total mass of the uneven nonwoven fabric, in order to obtain the effects of the thermoplastic fibers without reducing the effects of the cellulose fibers.

[0028] The uneven nonwoven fabric produced by the present invention typically has water absorption, breathability, and liquid permeability, and is therefore suitable for applications requiring such properties. Specific examples of applications of the uneven nonwoven fabric produced by the present invention include sanitary products such as absorbent articles, cosmetic sheets, and masks; and daily necessities such as cleaning wipes. The uneven nonwoven fabric produced by the present invention is particularly suitable for absorbent articles. Absorbent articles are worn articles that have the function of absorbing and retaining body fluids such as urine and sweat, and specific examples thereof include disposable diapers, sanitary napkins, panty liners, and incontinence pads. When the textured nonwoven fabric produced according to the present invention is used for sanitary products, it is preferable to make the textured surface with intermittently arranged convex portions, i.e., in the case of the textured nonwoven fabric 1 described above, the first surface 1a, the skin-facing surface that faces the skin of the user of the textured nonwoven fabric, so that the pleasant feel of the textured surface can be utilized.

[0029] Next, a method and an apparatus for producing the uneven nonwoven fabric of the present invention will be described. Fig. 3 shows a main part (hydroentanglement device 12) of a production apparatus 10 which is one embodiment of the apparatus for producing the uneven nonwoven fabric of the present invention. In the method for producing the uneven nonwoven fabric using the production apparatus 10, the uneven nonwoven fabric 1 described above is produced.

[0030] The manufacturing apparatus 10 includes a hydroentanglement device 12. The hydroentanglement device 12 is an apparatus that performs hydroentanglement treatment on a web 11 containing cellulose fibers, and includes a conveying mechanism 13 that conveys the web 11, a concave-convex support 20 on which the web 11 is placed while being conveyed by the conveying mechanism 13, and a water flow nozzle 17 that sprays a water flow onto the web 11 placed on the concave-convex support 20.

[0031] The conveying mechanism 13 includes a plurality of rolls 14 supported rotatably around a rotation axis, an endless conveyor belt 15 that is stretched across the plurality of rolls 14 and rotates in the direction of arrow R passing under a water flow nozzle 17, and a suction means 16 installed in the orbit of the conveyor belt 15. The conveyor belt 15 has a configuration that allows the water sprayed from the water flow nozzle 17 to pass through it, and may be, for example, a plain woven mesh support made of a wire material made of metal or synthetic resin, a porous support such as a punching plate, etc. The suction means 16 is disposed opposite the water flow nozzle 17 across the conveyor belt 15, and is configured to be able to suck in the water sprayed from the water flow nozzle 17 and permeating the conveyor belt 15.

[0032] The water flow nozzles 17 are disposed on the surface (lower surface) of the water flow spraying device 18 disposed above the transport mechanism 13 facing the conveyor belt 15. On the surface of the water flow spraying device 18 facing the conveyor belt 15, a plurality of water flow nozzles 17 are intermittently disposed over the entire length of the CD of the web 11 being transported below the facing surface to form a nozzle row extending in the CD, and a plurality of such nozzle rows are intermittently disposed in the MD. The nozzle rows are preferably disposed intermittently in 2 to 5 rows, more preferably 2 to 4 rows, in the MD. This group of water flow nozzles 17 makes it possible to spray the water flow 30 over the entire CD of the web 11 being transported in the MD by the transport mechanism 13.

[0033] The components of the hydroentanglement device 12, such as the transport mechanism 13 and the water jet device 18, other than the uneven support 20, may be configured in the same manner as those of the conventional hydroentanglement devices.

[0034] The concave-convex support body 20, which is one of the main characteristic parts of the manufacturing apparatus 10, will be described below. As shown in Figures 4 and 5, the uneven support 20 has a first surface 20a which is an uneven surface on which a plurality of protrusions 22 are formed, and a second surface 20b located on the opposite side. When the hydroentanglement treatment of the web 11 is performed by the hydroentanglement device 12, the web 11 is placed directly on the first surface 20a. In the illustrated embodiment, no protrusions are formed on the second surface 20b of the concave-convex support body 20, and the areas of the second surface 20b other than the through-holes 23 are flat. In the illustrated embodiment, the uneven support 20 is fixed to the conveyor belt 15 of the transport mechanism 13 via the second surface 20b, and rotates together with the conveyor belt 15 in the direction of arrow R. The method for fixing the uneven support 20 to the conveyor belt 15 is not particularly limited, provided that it does not impede the hydroentanglement treatment of the web 11, and examples of the method include a method using a fixing tool such as a bolt, an adhesive, or other known fixing means.

[0035] The uneven support body 20 forms a first surface 20a, which is an uneven surface, on which the web 11 of the uneven support body 20 is placed, and has a base plate 21 which forms the main body of the uneven support body 20, a plurality of protrusions 22 arranged on a surface of the base plate 21 which corresponds to the first surface 20a, and a plurality of through holes 23 which penetrate the base plate 21 in the thickness direction.

[0036] In the illustrated embodiment, the concave-convex support 20 is an integrally molded product made of a predetermined material, and the base plate 21 and the projections 22 are made of a common material and are inseparably integrated. In the illustrated embodiment, the base plate 21 is not formed by weaving wires, such as a wire mesh, but is a plate-like object made of a predetermined material. Note that in the present invention, a base plate formed by weaving wires may also be used as the base plate 21. The material of the uneven support 20 (base plate 21, protrusions 22) is not particularly limited, provided that it can be used in the hydroentanglement treatment of a web, and examples thereof include metals and plastics.

[0037] The protrusions 22 and through-holes 23 are scattered on the first surface 20a of the uneven support 20, i.e., the uneven surface on which the web 11 is placed during hydroentanglement treatment. "Scattered" here means that the protrusions 22 and through-holes 23 are each present scattered on the first surface 20a. For example, the protrusions 22 and / or through-holes 23 may be present only in a part of the first surface 20a, such as the central part or peripheral part, but from the viewpoint of improving the cushioning properties of the obtained uneven nonwoven fabric 1, it is preferable that the protrusions 22 and / or through-holes 23 are present scattered over the entire area of ​​the first surface 20a.

[0038] The protrusions 22 and through holes 23 scattered on the first surface 20a of the concave-convex support 20 may be arranged regularly or randomly. Here, "arranged regularly" refers to the protrusions 22 and through holes 23 being arranged according to a certain rule, while "arranged randomly" refers to an arrangement in which no such rule can be found. In the illustrated embodiment, the protrusions 22 and the through holes 23 are regularly arranged. Specifically, as shown in Figs. 4 and 5, the protrusions 22 and the through holes 23 are arranged in a staggered manner. Taking the protrusions 22 as an example, the "staggered arrangement" refers to an arrangement in which a plurality of protrusions 22 are arranged at equal intervals in one direction (MD or CD), and a plurality of rows are arranged in a direction perpendicular to the one direction (CD or MD), and the protrusions 22 are shifted from each other between two adjacent rows in the direction perpendicular to the one direction. The same applies to the staggered arrangement of the through holes 23. Since the protrusions 22 and the through holes 23 are arranged in a staggered manner, the protrusions 22 and the through holes 23 are alternately arranged on the first surface 20a in both the MD and CD that are perpendicular to each other, and the protrusions 22 are arranged at equal intervals at four locations around one through hole 23. In the illustrated embodiment, the through hole 23 is located in the center between the protrusions 22, 22 adjacent to each other in both the MD and CD.

[0039] The protrusions 22 promote the formation of the openings 4 or the bottoms of the recesses 3 during the hydroentanglement treatment of the web 11. Typically, when a water flow is sprayed onto the portion of the web 11 overlapping with the protrusions 22 during the hydroentanglement treatment, the fibers move from that portion to the surrounding area, and as a result, that portion (the source of the fiber movement) becomes the openings 4 in the uneven nonwoven fabric 1 where no fibers are present, or the bottoms of the recesses 3 having a smaller basis weight than before the hydroentanglement treatment. The shape of the protrusions 22 is not particularly limited, and any shape may be selected, provided that the function of the protrusions 22 can be fully exerted. The shapes of the multiple protrusions 22 may be different from one another.

[0040] In the illustrated embodiment, each of the multiple protrusions 22 has an elongated shape in the MD in a plan view as shown in Fig. 5(a), and has a pair of first surfaces 22A, 22A facing each other in the CD, and a second surface 22B connecting to the periphery of both surfaces 22A, 22A. Each surface 22A, 22B of the protrusion 22 may be a flat surface or a curved surface. In the illustrated embodiment, the first surface 22A is a flat surface, and the second surface 22B is a curved surface, and the second surface 22B has a convex arc shape toward the outside of the MD in a plan view as shown in Fig. 5(a). In addition, in the illustrated form, each of the multiple protrusions 22 has a tapered shape in which the width (length of MD) gradually decreases as it moves away from the base plate 21 in a cross-sectional view along the MD and thickness direction of the uneven support body 20 (height direction of the protrusions 22) as shown in Figure 5 (b), and the tip of the protrusion 22 is not sharp but has a rounded arc shape.

[0041] The through holes 23 are sites where the protrusions 2 are formed during the hydroentanglement treatment of the web 11. The shape of the through holes 23 is not particularly limited, and any shape may be selected, provided that the function of the through holes 23 can be fully exerted. In the illustrated embodiment, each of the multiple through holes 23 has a circular shape in a plan view as shown in FIG. 5(a), but instead of this, the multiple through holes 23 may have, for example, an elliptical shape, a triangular shape, or a rectangular shape. Furthermore, the multiple through holes 23 may have different shapes.

[0042] The uneven support 20 is characterized in that the opening area of ​​the through hole 23 and the thickness of the base plate 21 at the portion where the through hole 23 is formed are each set within a specific range. 2 More than 20mm 2 or less, and the thickness T (see FIGS. 4, 5(b) and 5(c)) of the portion of the base plate 21 where the through hole 23 is formed is 2.5 mm or more. As described above, the through holes 23 are the sites where the convex portions 2 of the uneven nonwoven fabric 1 are formed during the hydroentanglement treatment of the web 11. The open area of ​​the through holes 23 on the uneven surface side (the surface side on which the web 11 is placed) is set to 3.5 mm 2By setting the thickness to the above, it is possible to form the convex portions 2, and the concave-convex nonwoven fabric 1 can have a three-dimensional appearance. 2 By setting the above, it is possible to form uniform protrusions 2 without unevenness in size, and the aesthetics of the protrusion nonwoven fabric 1 will be improved. By making the thickness T of the portion of the base plate 21 where the through hole 23 is formed 2.5 mm or more, the required protruding height for the convex portion 2 (the height difference between the convex portion 2 on the first surface 1a and the bottom of the concave portion 3) can be ensured, which in turn makes the apparent thickness AT (see Figure 2) of the uneven nonwoven fabric 1 good. As a result, the unevenness of the uneven nonwoven fabric 1 is clearly visible and has a three-dimensional appearance and excellent aesthetics. The opening area of ​​the through hole 23 on the first surface 20a (concave-convex surface) side is 3.5 mm 2 More than 4.7 mm, preferably 2 More than 5.0mm, preferably 5.0mm 2 That's it, and 20mm 2 Less than or equal to 10 mm, preferably 2 The following is the result. The thickness T of the base plate 21 at the portion where the through-holes 23 are formed is 2.5 mm or more, preferably 2.7 mm or more, and more preferably 3 mm or more. There is no particular upper limit to the thickness T, but from the viewpoint of forming a uniform concave-convex shape, it is preferably less than 5 mm, and more preferably 4 mm or less.

[0043] In the illustrated embodiment, the base plate 21 has a uniform thickness, and the thickness is the same at the portion of the base plate 21 where the through hole 23 is formed and at other portions. However, in the present invention, on the premise that the thickness of the portion of the base plate 21 where the through hole 23 is formed is 2.5 mm or more, the thickness of the base plate 21 does not have to be uniform, and for example, the thickness of the portion of the base plate 21 other than the portion where the through hole 23 is formed may be less than 2.5 mm.

[0044] It is preferable that the opening area of ​​the through hole 23 is set within the above-mentioned specific range not only on the first surface 20a (uneven surface) side but also on the second surface 20b side located on the opposite side. In the illustrated embodiment, such a preferable embodiment is adopted. That is, in the uneven support body 20 shown in Figures 4 and 5, the opening area of ​​the through hole 23 is constant over the entire length in the depth direction of the through hole 23 (thickness direction of the base plate 21), and the opening area of ​​the through hole 23 is the same on the first surface 20a side and the second surface 20b side.

[0045] The ratio (H / T) of the height H of the protrusions 22 to the thickness T of the portion of the base plate 21 where the through-holes 23 are formed (see Figs. 5(b) and (c)) is preferably 0.8 or more, more preferably 1 or more, and preferably 1.5 or less, more preferably 1.3 or less. The thickness T of the portion of the base plate 21 where the through-holes 23 are formed corresponds to the depth of the through-holes 23, and when H / T is in the above-mentioned specific range, the web 11 can easily move from the protrusions 22 toward the through-holes 23 during the hydroentanglement treatment of the web 11, and the fine and beautiful protrusions 2 can be formed in the through-holes 23. As a result, the effect of the present invention, that is, the unevenness of the unevenness can be clearly seen and the unevenness of the unevenness can be efficiently produced, which is excellent in three-dimensionality and aesthetics, while containing cellulose fibers, can be more reliably achieved.

[0046] In order to ensure the effects of the present invention, the ratio (T / Lmax) of the thickness T of the portion of the base plate 21 where the through hole 23 is formed to the maximum diameter Lmax of the through hole 23 (see Figure 5) is preferably 0.5 or more, more preferably 1 or more, even more preferably 1.1 or more, and preferably 3 or less, more preferably 2 or less, even more preferably 1.3 or less.

[0047] In this specification, the "diameter length of a through hole" refers to the length of a virtual line drawn in a plan view of the through hole from one end to the other end of the through hole through the center of the through hole. If there are multiple virtual lines, the length of the one with the longest length in the extension direction is the "maximum diameter length Lmax," and the length of the one with the shortest length in the extension direction is the "minimum diameter length Lmin." The diameter of the through hole may vary depending on the measurement site. For example, the through hole 23 in the illustrated form has a cylindrical overall shape, a circular shape in a plan view, and a constant shape and size throughout the entire length of the through hole 23 in the depth direction (thickness direction of the base plate 21), so the through hole 23 has only one diameter, which is the diameter of the circle, and both the maximum diameter Lmax and the minimum diameter Lmin are equal to the diameter.

[0048] In order to ensure the effects of the present invention, it is preferable to set the dimensions of each part of the concave-convex support body 20 as follows. The height H of the projections 22 (see FIGS. 5(b) and (c)) is preferably 1.5 mm or more, more preferably 2 mm or more, even more preferably 2.6 mm or more, and is preferably 7 mm or less, more preferably 5 mm or less. The length L1 in the MD of the projection 22 (see FIGS. 5(a) and (b)) is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, more preferably 3.5 mm or less. The length L2 (see Figs. 5(a) and (c)) of the projection 22 in the CD direction is preferably 0.5 mm or more, more preferably 1 mm or more, and is preferably 4 mm or less, more preferably 2 mm or less.

[0049] The maximum diameter length Lmax (see FIG. 5) of the through hole 23 is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, more preferably 4 mm or less. The minimum diameter length Lmin of the through hole 23 is preferably 1.5 mm or more, more preferably 2 mm or more, even more preferably 2.5 mm or more, and is preferably 3.5 mm or less, more preferably 3 mm or less. It is preferable that the preferred ranges of the maximum diameter length Lmax and the minimum diameter length Lmin are filled at least at the opening end of the through hole 23 on the first surface 20a (uneven surface) side, and it is more preferable that they are filled over the entire area of ​​the through hole 23, as in the cylindrical through hole 23 shown in the figure.

[0050] The pitch 22P1 in the MD of the protrusions 22 (see FIGS. 5(a) and 5(b)) is preferably 4 mm or more, more preferably 5 mm or more, and preferably 14 mm or less, more preferably 8 mm or less. The "pitch 22P1" refers to the length along the MD between the centers of the MD of two adjacent protrusions 22, 22 in the MD. The pitch 22P2 (see FIGS. 5(a) and 5(c)) of the protrusions 22 in the CD is preferably 2 mm or more, more preferably 3 mm or more, and preferably 12 mm or less, more preferably 7 mm or less. The "pitch 22P2" refers to the length along the CD between the centers of the CDs of two adjacent protrusions 22, 22 in the CD. The pitch 23P1 in the MD of the through holes 23 (see FIGS. 5(a) and 5(b)) is preferably 4 mm or more, more preferably 6 mm or more, and preferably 14 mm or less, more preferably 7 mm or less. The "pitch 23P1" refers to the length along the MD between the centers of the MD of two adjacent through holes 23, 23 in the MD. The pitch 23P2 (see FIGS. 5(a) and 5(c)) of the through holes 23 in the CD is preferably 1 mm or more, more preferably 3 mm or more, and preferably 10 mm or less, more preferably 7 mm or less. The "pitch 23P2" refers to the length along the CD between the centers of each of two adjacent through holes 23, 23 in the CD.

[0051] The area ratio of the through holes 23 in the uneven support 20, i.e., "the ratio of the total opening area of ​​all the through holes 23 arranged on the surface corresponding to the first surface 20a of the uneven support 20 in the base plate 21 to the total area of ​​the surface corresponding to the first surface 20a of the uneven support 20," is not particularly limited, but from the viewpoint of ensuring the effects of the present invention and the strength of the base plate 21, it is preferably 20% or more, more preferably 25% or more, and preferably 50% or less, more preferably 40% or less, even more preferably 35% or less, and even more preferably 33% or less.

[0052] The manufacturing apparatus 10 may include a web forming apparatus (not shown) in addition to the hydroentanglement apparatus 12. The web forming apparatus forms the web 11 to be subjected to hydroentanglement treatment in the hydroentanglement apparatus 12, and is disposed upstream of the hydroentanglement apparatus 12 in the MD. As the web forming apparatus, any apparatus that produces a web using a known web forming method such as a dry method or a wet method can be used without any particular limitation. The web forming apparatus typically includes a carding machine, and forms a web by a carding method, which is a type of dry method. In the present invention, the web may have a single layer structure, or may have a laminated structure in which two or more layers are laminated.

[0053] In the present invention, the term "web" refers to a fiber assembly in which the fibers are not substantially bonded to each other, i.e., the fibers are not bonded to each other. Specifically, the term "web" refers to a fiber assembly formed by a known web forming method such as a dry method, and which has not been subjected to a treatment by a known interfiber bonding method such as a hydroentanglement method, a thermal bond method, a chemical bond method, or a needle punch method.

[0054] In the method for producing a concavo-convex nonwoven fabric of the present invention, the web is subjected to a water jetting step to perform hydroentanglement treatment, thereby entangling the constituent fibers of the web and essentially bonding them together. When the web is composed mainly of cellulose fibers such as cotton fibers as its constituent fibers (specifically, for example, when the mass ratio of cellulose fibers to the total mass of the constituent fibers of the web is preferably 50 mass% or more, more preferably 75 mass% or more), typically, as in the first manufacturing method described below, the web is subjected to the hydroentanglement treatment and then dried as necessary, whereby the web becomes a nonwoven fabric in which the constituent fibers are substantially bonded to each other. In addition, when the web contains thermoplastic fibers in addition to cellulose fibers as constituent fibers, it is preferable to further subject the web to a heat treatment after the hydroentanglement treatment, as in the second manufacturing method described below. The heat treatment is a treatment in which the web is heated at a temperature equal to or higher than the melting point of the thermoplastic fibers contained in the web, whereby the thermoplastic fibers are fused together and substantially bonded. Therefore, in a web that has been subjected to both the hydroentanglement treatment and the heat treatment, the cellulose fibers are substantially bonded together by entanglement, the thermoplastic fibers are substantially bonded together by fusion, and further, the cellulose fibers and the thermoplastic fibers can be bonded together by fusion.

[0055] The manufacturing apparatus 10 may include a drying device (not shown) that removes moisture from the web that has been hydroentangled by the hydroentanglement device 12. The drying device is basically intended to remove moisture from the fiber aggregate (drying treatment), but may also be used to melt and fuse the thermoplastic fibers contained in the web (heating treatment). In the method for manufacturing a nonwoven fabric with unevenness of the present invention, the drying device may be used to simultaneously dry and heat the fiber aggregate. The drying device is disposed downstream of the hydroentanglement device 12 in the MD. As the drying device, any device that can be used to dry a web that has been hydroentangled in a spunlace nonwoven fabric manufacturing apparatus can be used without any particular restrictions. Specific examples of the drying treatment by the drying device include blowing hot air, blowing dry gas, heating with a heater, irradiation with infrared rays, contact with a heating roll, and suction of moisture using a suction roll or the like.

[0056] Next, a method for producing the uneven nonwoven fabric of the present invention will be described by taking as an example a method for producing the uneven nonwoven fabric 1 using the above-mentioned production apparatus 10. The method for producing a concave-convex nonwoven fabric of the present invention includes at least a water jetting step, in which, as shown in Fig. 3, a web 11 containing cellulose fibers is placed on the first surface 20a (concave-convex surface) of a concave-convex support 20, and water jets 30 are jetted onto the web 11 from a water jet nozzle 17 to entangle the fibers contained in the web 11 and form convex portions 2 (see Fig. 1, etc.) in the web 11.

[0057] Since the uneven nonwoven fabric 1 which is the object of manufacture has the openings 4, in the water jetting step, the water jets 30 are jetted onto the portions of the web 11 which correspond to the projections 22 to form the openings 4.

[0058] The water jetting step is shown in Fig. 6. Fig. 6(a) shows the state in which the web 11 is placed on the first surface 20a of the uneven support 20, immediately before the hydroentanglement treatment is performed. The web 11 before the hydroentanglement treatment is substantially flat, without any unevenness. As the conveyor belt 15, which is fixed to the uneven support 20 via the second surface 20b, rotates from the state shown in Fig. 6(a), the web 11 and the uneven support 20 are transported together to the MD, and when they reach directly below the water jetting device 18, as shown in Fig. 6(b), a water jet 30 jetted from the water jet nozzle 17 of the water jetting device 18 is sprayed onto the web 11. As described above, the water jet 30 is sprayed uniformly over the entire CD of the web 11, and is sprayed approximately perpendicularly to the web 11. In the portion of the web 11 where the water jet 30 is sprayed, the constituent fibers of the portion are entangled, and the portion is pressed toward the uneven support 20, and is deformed to fit the first surface 20a (uneven surface). At this time, the constituent fibers of the web 11 at the portions corresponding to the protrusions 22 are separated by the water streams 30 sprayed from above and the protrusions 22 supporting the portions from below, and are penetrated by the protrusions 22, ultimately forming the openings 4 (areas where the fiber basis weight is zero) as shown in FIG. 6(c). The fibers separated from the portions corresponding to the protrusions 22 in the web 11 in this way are moved into the through holes 23 by the water flowing from the protrusions 22 toward the through holes 23 on the first surface 20a of the uneven support 20. During the hydroentanglement treatment, the opening ends of the through holes 23 on the second surface 20b side (the opening ends opposite the inflow side of the water and fibers) are blocked by the conveyor belt 15 at least to an extent that the fibers are difficult to flow out, so that the fibers that have moved from the surrounding area are accumulated inside the through holes 23, and ultimately, the protrusions 2 (high basis weight portions 5) are formed as shown in FIG. 6(c). Furthermore, the areas of the first surface 20a of the uneven support 20 other than the protrusions 22 and the through-holes 23 are flat areas without unevenness, and the areas of the web 11 corresponding to these flat areas are pressed toward the flat areas by the water flow 30, ultimately becoming the bottoms of the recesses 3 (low basis weight areas 6) as shown in Fig. 6(c). In this way, the hydroentanglement treatment forms the protrusions 2, the bottoms of the recesses 3, and the openings 4 in the web 11, and the constituent fibers of the web 11 are entangled, turning the web 11 into an uneven nonwoven fabric 1 (first manufacturing method). In addition, when web 11 contains cellulose fibers such as cotton fibers and thermoplastic fibers, it is preferable to subject web 11 to a heating step after hydroentanglement treatment of web 11, as in the second manufacturing method described below, and to perform a heat treatment in which web 11 is heated to a temperature equal to or higher than the melting point of the thermoplastic fibers contained in web 11, whereby the thermoplastic fibers are substantially bonded to each other by fusion, and web 11 becomes a textured nonwoven fabric 1.

[0059] The uneven nonwoven fabric 1 thus manufactured has an excellent three-dimensional appearance and a good appearance and texture because the "opening area of ​​the through-holes 23 on the first surface 20a (uneven surface) of the uneven support 20" and the "thickness T of the base plate 21 at the portion where the through-holes 23 are formed" which have a significant effect on the formation of the protrusions 2 are each set within the above-mentioned specific ranges, or in addition to these two elements, the "ratio (H / T) of the height H of the protrusions 22 to the thickness T of the base plate 21 at the portion where the through-holes 23 are formed" is also set within the above-mentioned specific ranges. This is demonstrated by the examples described later.

[0060] In particular, as shown in FIG. 5(a) and the like, the uneven support 20 in the illustrated form has a plurality of (four) protrusions 22 arranged on the first surface 20a so as to surround one through hole 23 whose open area is within the specific range. Therefore, water sprayed onto the first surface 20a during the hydroentanglement treatment is likely to converge from the plurality of protrusions 22 toward the one through hole 23. Therefore, the fibers of the web 11 that have moved with the water from the surrounding plurality of protrusions 22 are likely to accumulate in the through hole 23, and thus the protrusions 2 (high basis weight portion 5) are likely to be formed. In addition, when the fibers move from the plurality of places around the through hole 23 and accumulate in the through hole 23 in this way to form the protrusions 2, the micro recesses are likely to be formed on the opposite side to the tops of the protrusions 2. The micro recesses are expected to have the effect of increasing the cushioning properties of the uneven nonwoven fabric 1 together with the protrusions 2.

[0061] In the water jetting step, the MD conveying speed of the web 11 and the water pressure of the water jet sprayed from the water jet nozzle 17 are not particularly limited, but from the viewpoint of ensuring the effects of the present invention, it is preferable to set them as follows. The MD transport speed of the web 11 is preferably 1 m / min or more, more preferably 3 m / min or more, and preferably 120 m / min or less, more preferably 100 m / min or less. The water pressure of the water jetted from the water jet nozzle 17 is preferably 0.1 MPa or more, more preferably 0.3 MPa or more, and is preferably 10 MPa or less, more preferably 8 MPa or less. The nozzle hole diameter of the water flow nozzle 17 is preferably 0.03 mm or more, more preferably 0.05 mm or more, even more preferably 0.08 mm or more, and preferably 0.50 mm or less, more preferably 0.30 mm or less, even more preferably 0.20 mm or less. When multiple water flow nozzles 17 are intermittently arranged over the entire length of the CD, the nozzle hole pitch of the water flow nozzles 17 is preferably 0.1 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and preferably 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.0 mm or less.

[0062] As in the water flow jetting device 18 shown in FIG. 3, when a nozzle row consisting of a water flow nozzle or a plurality of water flow nozzles intermittently arranged in the CD is intermittently arranged in the MD, the water pressure of the water flow jetted from the water flow nozzle located on the upstream side of the MD may be made different from that of the water flow nozzle located on the downstream side. Specifically, for example, the water pressure of the water flow jetted from the water flow nozzle may be gradually increased from the upstream side to the downstream side of the MD. Similarly, the nozzle hole diameter of the water flow nozzle located on the upstream side of the MD may be made different from that of the water flow nozzle located on the downstream side. Specifically, for example, the nozzle hole diameter may be gradually increased from the upstream side to the downstream side of the MD. Furthermore, when a nozzle row consisting of a plurality of water flow nozzles intermittently arranged in the CD is intermittently arranged in the MD, the nozzle hole pitch of the nozzle row located on the upstream side of the MD may be made different from that of the nozzle row located on the downstream side. Specifically, for example, the nozzle hole pitch may be gradually decreased from the upstream side to the downstream side of the MD. This can further improve the texture of the uneven nonwoven fabric.

[0063] After the water jetting step, if necessary, a drying step may be carried out to remove moisture from the uneven nonwoven fabric 1 obtained in the water jetting step. That is, the method for producing an uneven nonwoven fabric of the present invention may include the drying step after the water jetting step. The drying step can be carried out in a conventional manner using the drying device.

[0064] The method for producing a nonwoven fabric with a concave-convex shape according to the present invention includes 1) an embodiment in which the drying step is carried out as necessary after the water jetting step (hereinafter also referred to as the "first production method"), and 2) an embodiment in which the drying step is carried out as necessary after the water jetting step, and further includes a heating step of heat-treating the web (hereinafter also referred to as the "second production method"). The first production method is as described above. The second production method is the same as the first production method, except that it includes a heating step. Typically, the first production method is applied when the nonwoven fabric with a concave-convex shape, which is the object of production, contains only cellulose fibers such as cotton fibers as constituent fibers, and the second production method is applied when the nonwoven fabric with a concave-convex shape, which is the object of production, contains cellulose fibers and thermoplastic fibers as constituent fibers. The web used in the first production method contains only cellulose fibers, and the web used in the second production method contains cellulose fibers and thermoplastic fibers.

[0065] The second manufacturing method will be described below. In addition to the water jetting step, the second manufacturing method further includes a heating step of heating the web that has been subjected to the water jetting step at a temperature equal to or higher than the melting point of the thermoplastic fibers contained in the web. By subjecting a web containing cellulose fibers and thermoplastic fibers to the water jetting step, the cellulose fibers are substantially bonded to each other by entanglement, and by subjecting the web to the heating step, the thermoplastic fibers are substantially bonded to each other by fusion, resulting in a textured nonwoven fabric. In the heating step, not only the thermoplastic fibers but also the thermoplastic fibers and the cellulose fibers can be bonded to each other by fusion. According to the second manufacturing method, the bonding strength of the web is improved, the handleability of the web in the manufacturing process is improved, and the strength of the finally obtained textured nonwoven fabric can be improved. When two or more types of thermoplastic fibers with different melting points are used, it is preferable to heat the web in the heating step at a temperature equal to or higher than the highest melting point. When the second manufacturing method is carried out using the above-mentioned manufacturing apparatus 10, a heating device for carrying out the heating step is disposed downstream in the MD from the hydroentanglement device 12. Specific examples of the heat treatment performed on the web by the heating device include blowing hot air, heating with a heater, contact with a heating roll, and irradiation with infrared rays.

[0066] In the second manufacturing method, the content of thermoplastic fibers in the web may be adjusted to be the same as the content of thermoplastic fibers in the embossed nonwoven fabric that is the intended product, as described above. The distribution form of the thermoplastic fibers in the web is not particularly limited, and may be, for example, uniformly distributed throughout the web together with the cellulose fibers, or may be unevenly distributed. A specific example of the latter is a form in which the web has a first layer mainly composed of cellulose fibers and a second layer containing thermoplastic fibers, and both layers are laminated in the thickness direction.

[0067] Fig. 7 shows another embodiment of the concave-convex support body according to the present invention. In the other embodiment described below, components different from the above-mentioned embodiment (convex-convex support body 20) will be mainly described, and similar components will be given the same reference numerals and description will be omitted. For components not specifically described, the description of the above-mentioned embodiment will be applied as appropriate.

[0068] The uneven support 25 shown in FIG. 7 is characterized in that at least a part of the surface of the protrusions 22 has a rough surface. Specifically, the multiple protrusions 22 arranged on the first surface 20a of the uneven support 25 each have a rough surface on the second surface 22B. The rough surface on the second surface 22B is obtained by a roughening treatment that forms multiple grooves 26 on the second surface 22B. The multiple grooves 26 extend parallel to the first surface 20a and are intermittently arranged in the height direction of the protrusions 22. Portions other than the peripheral portion of the first surface 22A of the protrusions 22 are not roughened and do not have a rough surface, and are smoother than the second surface 22B. When the surfaces of the protrusions 22 have a rough surface in this manner, when a water flow is sprayed onto the web during hydroentanglement treatment, the constituent fibers of the web are less likely to slide off the surface of the protrusions 22 and are more likely to be appropriately caught in the rough surface portions, making it easier for the web to conform to the shape of the protrusions 22 and resulting in a textured nonwoven fabric with excellent three-dimensional feel. There are no particular limitations on the roughened portions on the surface of the protrusions 22. For example, the protrusions 22 shown in Fig. 7 may have a roughened surface on the first surface 22A in addition to or instead of the second surface 22B. The roughening treatment method may be any method that can roughen the surface of the protrusions 22, that is, reduce the smoothness of the surface of the protrusions 22, and is not limited to the method of forming grooves as shown in the figure.

[0069] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present invention. In the above embodiment, in the water jetting step, the water jet is jetted onto the portions of the web 11 corresponding to the protrusions 22 to form the openings 4, but in the present invention, forming the openings 4 is not essential and can be selected arbitrarily. Preventing the formation of openings in the uneven nonwoven fabric can be achieved by appropriately adjusting the water pressure of the water jet sprayed onto the web and the shape of the protrusions of the uneven support in the water jetting step. EXAMPLES

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples.

[0071] [Examples 1, 3 to 8, Comparative Examples 1 and 2] A nonwoven fabric was produced by the first manufacturing method. Specifically, a nonwoven fabric was produced by subjecting a web to a hydroentanglement treatment using an apparatus having a similar basic configuration to the manufacturing apparatus (hydroentanglement apparatus) shown in FIG. 3. Cotton fibers, which are a type of cellulose fiber, were used as the raw fiber of the web, and a single-layered web was formed by a carding method in the usual manner. The hydroentanglement treatment was carried out by spraying a water flow onto the web in a state in which the web was placed on one side (the uneven surface) of a corrugated support. In the hydroentanglement treatment, a nozzle row consisting of a plurality of water flow nozzles intermittently arranged in the CD and three rows intermittently arranged in the MD was used as a water flow spraying apparatus, and the hydroentanglement treatment was carried out by introducing the web into the water flow spraying apparatus twice. The conditions for the hydroentanglement treatment and the details of the corrugated support are shown in Table 1 below. In Table 1 below, the water flow nozzle in the nozzle row arranged at the most upstream side of the MD is called water flow nozzle A, and water flow nozzle B and water flow nozzle C are arranged in order toward the downstream side of the MD. The water flow nozzles A and B used had a nozzle hole diameter of 0.1 mm and a nozzle hole pitch of 1.0 mm, while the water flow nozzle C used had a nozzle hole diameter of 0.12 mm and a nozzle hole pitch of 0.6 mm.

[0072] Example 2 A nonwoven fabric was produced by the second production method. Specifically, the web to be subjected to the water jet entanglement treatment was changed, and a heating step was performed after the water jet spray step to heat-treat the web that had been subjected to the water jet spray step. Except for the above points, the nonwoven fabric was produced in the same manner as in Example 1 and the like. The web used in Example 2 was a laminated web having a laminated structure of a first layer, which was the surface side directly sprayed with the water flow in the hydroentanglement treatment, and a second layer, which was the surface side in contact with the uneven support, the first layer being made of only cotton fibers, and the second layer being made of cotton fibers and thermoplastic fibers. As the thermoplastic fibers, core-sheath type composite fibers having a fineness of 2.4 dtex and a core part made of polyethylene terephthalate and a sheath part made of polyethylene were used. The content of the thermoplastic fibers in the laminated web was 25% by mass with respect to the total mass of the laminated web. The laminate web was formed as follows. First, a first layer was obtained by a conventional carding method using cotton fibers, which are a type of cellulose fiber. Next, a fiber mixture in which the cotton fibers and the thermoplastic fibers were mixed in equal amounts was used to obtain a second layer by a conventional carding method. Then, the first layer and the second layer were superimposed to form the laminate web. The hydroentanglement treatment was carried out by spraying a water flow onto the laminated web while the laminated web was placed on one side (the uneven surface) of a concave-convex support so that the convex side became the first layer composed only of cotton fibers, and the conditions (water pressure, etc.) were the same as in Example 1 to obtain a hydroentangled web. The heating step was carried out by subjecting the hydroentangled web to hot air treatment using an air-through device (heating device) under heat conditions of a temperature of 136° C. and an air speed of 1.2 m / s for about 15 seconds. Prior to carrying out the heating step, the hydroentangled web was dried for about one day (drying step) in order to remove moisture contained in the web.

[0073] The nonwoven fabrics produced in the Examples and Comparative Examples were evaluated for the shape of the openings and the shape of the irregularities by the following methods. The results are shown in Table 1 below.

[0074] <Evaluation method for hole shape> The nonwoven fabrics to be evaluated were visually observed and rated according to the following evaluation criteria. The evaluation was carried out by 10 trained panelists. In the following evaluation criteria, "A" is a better evaluation than "C". (Evaluation criteria for hole shape) A: The holes are clearly visible (clean holes are formed at uniform intervals) B: Slightly visible holes (irregular shape, spacing, or both) C: No visible holes (shape or spacing is significantly uneven, or holes cannot be recognized)

[0075] <Method of evaluating unevenness> The nonwoven fabrics to be evaluated were visually observed and rated according to the following evaluation criteria. The evaluation was carried out by 10 trained panelists. In the evaluation criteria below, "A" is a better evaluation than "C." The three-dimensional effect of the uneven nonwoven fabric can be confirmed by the clarity of the unevenness. (Evaluation criteria for uneven shape) A: The unevenness is clearly visible (evenly spaced and with a clean uneven shape) B: Slight irregularities are visible (either the spacing or the shape, or both, are uneven) C: No visible irregularities (shape or spacing is significantly uneven, or irregularities cannot be recognized)

[0076] [Table 1] [Explanation of symbols]

[0077] 1 Uneven nonwoven fabric 2 Convex 10. Uneven nonwoven fabric manufacturing equipment 11. Web 12 Hydroentangling device 13. Conveyor mechanism 17 Water jet nozzle 20,25 Uneven support 20a: First surface (concave-convex surface) of the uneven support 21 Base plate 22 protrusions 23 Through hole

Claims

1. A method for producing a concave-convex nonwoven fabric containing cellulose fibers and having a plurality of convex portions intermittently arranged on at least one surface, comprising: a water jetting step of placing a web containing cellulose fibers on a textured surface of a textured support having a textured surface on which a plurality of protrusions are formed, and then jetting a water jet over the entire area of ​​the web to entangle the fibers contained in the web and form the protrusions on the web, the uneven support body has a base plate that forms a surface of the uneven support body on which the web is placed, a plurality of the protrusions that are arranged on a surface of the base plate that corresponds to the uneven surface, and a plurality of through holes that penetrate the base plate in a thickness direction, the protrusions and the through holes being scattered on the uneven surface, The opening area of ​​the through hole on the uneven surface side is 3.5 mm ２ More than 20 mm ２ is as follows: A method for producing a textured nonwoven fabric, wherein the thickness of the base plate at the location where the through holes are formed is 2.5 mm or more.

2. The method for producing a concave-convex nonwoven fabric according to claim 1 , wherein the ratio of the height of the protrusions to the thickness of the base plate is 0.8 or more and 1.5 or less.

3. The uneven nonwoven fabric has a plurality of openings penetrating the uneven nonwoven fabric in the thickness direction, The method for producing a concave-convex nonwoven fabric according to claim 1 or 2, wherein the water jet spraying step forms the openings in the web at locations corresponding to the protrusions.

4. A method for producing a concave-convex nonwoven fabric according to claim 1 or 2, wherein the protrusions and the through holes are arranged alternately on the concave-convex surface of the concave-convex support body in both one direction and a direction intersecting the one direction.

5. The method for producing a concavo-convex nonwoven fabric according to claim 1 or 2, wherein a ratio of a thickness of the base plate at a portion where the through holes are formed to a maximum diameter length of the through holes is 0.5 or more and 3.0 or less.

6. The method for producing a concave-convex nonwoven fabric according to claim 1 or 2, wherein the web further contains thermoplastic fibers.

7. A heating step is carried out after the water jet spraying step, the heating step includes a step of heating the web that has been subjected to the water jet spraying step at a temperature equal to or higher than the melting point of the thermoplastic fibers, The method for producing a concave-convex nonwoven fabric according to claim 6 , wherein the content of the thermoplastic fibers in the web is 5% by mass or more and less than 50% by mass.

8. The method for producing a concavo-convex nonwoven fabric according to claim 1 or 2, wherein at least a portion of the surface of the protrusions has a rough surface.

9. An apparatus for producing a concave-convex nonwoven fabric containing cellulose fibers and having a plurality of convex portions intermittently arranged on at least one surface, A hydroentangling device is provided for subjecting a web containing cellulose fibers to a hydroentangling treatment, the hydroentangling device comprises a transport mechanism for transporting the web, a concave-convex support on which the web is placed while being transported by the transport mechanism, and a water flow nozzle for spraying a water flow onto the web placed on the concave-convex support; the uneven support body includes a base plate having an uneven surface on which a plurality of protrusions are formed, and a plurality of through holes penetrating the base plate in a thickness direction, the protrusions and the through holes being scattered on a surface of the base plate on which the web is placed, The opening area of ​​the through hole on the uneven surface side is 3.5 mm ２ More than 20 mm ２ is as follows: An apparatus for manufacturing a textured nonwoven fabric, wherein the thickness of the portion of the base plate where the through holes are formed is 2.5 mm or more.

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