JP2006348438A - Nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonwoven fabric which gives little load to environments from production to scrapping, has dynamic strengths equal to or larger than those of synthetic fibers, has the characteristic comfort appearance of a natural material, uses the characteristics, and can be used for uses such as various packaging materials, wallpaper, roofing base fabrics, anti-corrosive tapes, various reinforcing materials, for example, cable-reinforcing materials, press wrapping materials, wearing plates, or concrete-reinforcing materials, various wearing fabrics, isolation membranes, separation membranes, separators, and clothing members. <P>SOLUTION: This nonwoven fabric is characterized in that fibers comprising fibers derived from a natural substance in a content of ≥50 wt.% and synthetic fibers and/or regenerated fibers in a content of <50 wt.% are three-dimensionally interlaced with each other, and the basis weight and penetration strength of the fabric are 5 to 500 g/m<SP>2</SP>and ≥4N, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nonwoven fabric using fibers containing fibers derived from natural products and a method for producing the same. More specifically, the present invention relates to a non-woven fabric having mechanical properties equal to or higher than those of synthetic fibers and having a feeling of peace peculiar to natural products even though the environmental load is small from production to disposal.

  Nonwoven fabrics can be shaped into a cloth state in one step without separating the spinning and processing steps like woven and knitted fabrics, so the production scale shows a high production increase rate, living materials, medical hygiene materials, bedding, It is used for various purposes such as clothing materials. The raw material fibers used for the nonwoven fabric are mainly synthetic fibers such as polyester fibers and polypropylene fibers and regenerated fibers such as rayon. However, since synthetic fiber is a raw material of petroleum and difficult to dispose of, environmental concerns are of great concern today, and there is an increasing demand to reduce its use as much as possible and to replace synthetic fibers in the future. It is growing. Nonwoven fabrics using regenerated fibers are made from natural products such as pulp and bamboo. However, at the stage of regenerating fibers, chemicals with high environmental impact such as carbon disulfide that are difficult to recover and highly toxic are used. It is not necessarily an environmentally friendly non-woven fabric due to the large amount of energy used in the fiber manufacturing process.

On the other hand, a non-woven fabric using synthetic fibers and recycled fibers is a non-woven fabric with high mechanical strength. In particular, in order to play a role as a cloth, a nonwoven fabric with high penetration strength is required.
Therefore, if a technique for producing a nonwoven fabric without substantially chemically treating natural fibers and reducing the amount of energy used as much as possible can be obtained, it can be an environment-friendly nonwoven fabric suitable for the 21st century.

Several attempts have been made to propose such nonwoven fabrics.
For example, a cotton non-woven fabric using a hydroentanglement method using cotton has been used for a long time as disclosed in Non-Patent Document 1, for example. However, cotton nonwoven fabrics have problems that penetration strength is low, quality varies, and it is difficult to avoid contamination. Further, for example, Patent Document 1 proposes a nonwoven fabric made from jute, sisal hemp or the like. However, these nonwoven fabrics have problems that the distance between the entanglement points of the fibers cannot be shortened, and that the constituent fibers are difficult to be entangled, so that the penetration strength is low. In addition, there are inherent problems such as the fiber easily falling off and the uneven thickness of the nonwoven fabric due to the non-uniformity of the raw materials.
As described above, according to the conventional technology, a nonwoven fabric using natural fibers and having excellent penetration strength has not been obtained.

"Basics and Applications of Nonwoven Fabrics" Japan Textile Machinery Society, Nonwoven Fabric Research Group, P156-P160 (issued August 25, 1993) Japanese translation of PCT publication No. 2002-514272

  The present invention uses natural product fibers having excellent penetration strength, which have mechanical properties equal to or higher than those of synthetic fibers, and have a feeling of peace peculiar to natural products even though the environmental load is small from production to disposal. The purpose is to provide a nonwoven fabric.

As a result of intensive studies to solve the above problems, the present inventors have studied the shape of natural fibers and the method of processing nonwoven fabrics in detail, and as a result, have a penetration strength equivalent to or higher than that of synthetic fibers and recycled fibers. The inventors have found that it is possible to produce a nonwoven fabric made of natural product fibers, and have completed the present invention.

That is, the present invention is a nonwoven fabric characterized in that a fiber containing a natural product-derived fiber is three-dimensionally entangled, has a basis weight of 5 to 500 g / m ² , and a penetration strength of 4N or more. Manufacturing a non-woven fabric characterized by comprising a step of forming a fiber sheet containing fibers derived from natural products and then tangling the fibers three-dimensionally by a fluid flow treatment so that the distance between the fiber entanglement points is 400 μm or less. A method is provided.

  The present invention is made from a natural product-derived fiber as it is, without substantially adding chemical modification, for example, by using non-woven fabric made by pulverization after drying, etc. Very little environmental impact. In addition, since the quality and foreign matter contamination is less than conventional nonwoven fabrics composed of natural product-derived fibers, and the mechanical strength such as penetration strength is high, the nonwoven fabric is not torn during use. Therefore, it can be used for various industrial uses, material uses, hygiene uses, and the like, and has a feeling of peace peculiar to natural products. In addition, depending on the type of the fiber of the natural product-derived component used, such as bamboo and cocoon, the fiber itself has antibacterial and antibacterial properties, and a physiological activity can be expected.

The present invention will be specifically described below.
The nonwoven fabric of the present invention is a nonwoven fabric characterized by three-dimensional entanglement of fibers containing fibers derived from natural products, a basis weight of 5 to 500 g / m ² , and a penetration strength of 4N or more.
The natural product-derived fiber of the present invention may be any of vegetable fiber, animal fiber, and mineral fiber, but is preferably vegetable fiber from the viewpoint of ease of processing and availability, and particularly bamboo. Cedar, straw, kenaf, sugar cane and pineapple are preferred. The plant utilization site may be either the epidermis or the internal fiber, and can be arbitrarily selected according to the purpose. There is no restriction | limiting in particular about the length of the natural product origin fiber contained in the nonwoven fabric of this invention, A short fiber or a long fiber may be sufficient.

  The fiber derived from a natural product can be produced by pulverizing the raw plant as it is or after drying. As a pulverization method, mechanical pulverization, explosion pulverization, chemical pulverization using alkali or the like can be used, but it is preferable to manufacture by pulverization. This is because when the chemical pulverization using explosion or alkali is used, the degree of polymerization of cellulose of the fiber derived from the natural product is lowered and the penetration strength is lowered. As a polymerization degree of the cellulose which comprises the fiber derived from a natural product, 400-1500 are preferable, Most preferably, it is 400-1200.

  There is no restriction | limiting in particular about the length of the natural product origin fiber contained in the nonwoven fabric of this invention, A short fiber or a long fiber may be sufficient. When the fiber length is too long, when the nonwoven fabric is used, the fibers are entangled and become uneven, and the barrier property is partially reduced, or the basis weight of the sheet obtained by the papermaking method may be reduced. On the other hand, if the fiber length is too short, the fibers may not be entangled easily, and the fibers may be easily lost, and sufficient strength may not be exhibited. From the viewpoint of the uniformity and formability of the nonwoven fabric, it is preferably a short fiber having a fiber length of 0.5 to 75 mm, more preferably 1 to 60 mm, and even more preferably 5 to 50 mm.

As the shape derived from the natural product used in the present invention, the diameter of the single yarn is preferably 1 μm to 2 mm, and the ratio L / D of the fiber length L to the single yarn diameter D is preferably 50 to 10,000. The reason is that the entanglement property when making a nonwoven fabric within this range is good and the penetration strength can be increased. When the diameter of the single yarn is less than 5 μm, it becomes difficult to uniformly disperse in water when hydroentangled. In particular, if it exceeds 2 mm, it may be difficult to entangle. Preferably, they are 10 micrometers-1 mm, More preferably, they are 10 micrometers-800 micrometers. L / D is preferably 100 to 6000, more preferably 300 to 5000, and particularly preferably 350 to 4500. When it exceeds 10,000, the fibers are entangled with each other and the uniformity of the sheet is deteriorated, and the target nonwoven fabric may not be obtained depending on the production conditions.
The specific surface area of the natural product-derived fiber is preferably 0.05 to 50 m ² / g. 0.05m mechanical strength is lowered and it ² / g or less, there is a case where too fine When it is 50 m ² / g or more through strength is reduced. Preferably it is 0.05-5 m < ² > / g, Most preferably, it is 0.05-3 m < ² > / g.

In addition, the nonwoven fabric of the present invention may contain fibers other than the fibers derived from natural products as long as the object of the present invention can be achieved. In particular, it is preferable to mix fibers other than those derived from natural products when the confounding property of the fibers derived from natural products is poor or to impart heat shaping properties. Examples thereof include polyethylene terephthalate fiber, polytrimethylene terephthalate fiber, polybutylene terephthalate fiber, polylactic acid fiber, acrylic fiber, polyamide fiber, polyethylene fiber, polypropylene fiber, polyacrylic fiber, copper ammonia rayon, rayon and other regenerated cellulose. Examples thereof include synthetic fibers such as fibers, cellulose acetate fibers, aramid fibers, polyvinyl alcohol fibers, and polybenzazole fibers. The shape of these fibers is not particularly limited, but short fibers having a fiber length of 0.5 to 75 mm, single yarn fineness of 0.1 to 2 dtex, and L / D of 50 to 10,000 are preferable. Although there is no restriction | limiting in particular as a mixing ratio to a nonwoven fabric, It is less than 50 wt% of a nonwoven fabric weight, Preferably it is 30 wt%, Most preferably, it is less than 20 wt%.
Inside the nonwoven fabric, the above-mentioned fibers derived from natural products or fibers other than those mixed as necessary need to be entangled three-dimensionally. Such entanglement is effective in improving the basis weight and penetration strength, handling properties, and preventing the fibers from falling off.

The nonwoven fabric of the present invention contains components other than fibers such as adhesives, additives, surface coating agents, water repellents, hydrophilic agents and other surface modifiers, resins, rubbers, and films as necessary. Also good.
The basis weight of the nonwoven fabric of the present invention is required to be 5 to 500 g / m ² . When the basis weight is less than 5 g / m ^2, it is difficult to obtain a nonwoven fabric with high penetration strength, and the shape retention is inferior, resulting in problems such as wrinkling. Although there is no restriction | limiting in particular about the upper limit of a fabric weight, It is preferable that it is 500 g / m < ² > or less from viewpoints of the uniformity of the entanglement inside a nonwoven fabric, the uniformity of a nonwoven fabric thickness, surface smoothness, etc. A more preferable range of the basis weight is 20 to 250 g / m ² , and a more preferable range is 20 to 100 g / m ² .

The nonwoven fabric of the present invention needs to have a penetration strength of 4N or more. If the penetration strength is less than 4N, problems such as damage to the nonwoven fabric or opening of holes due to external forces such as impact and butting are likely to occur during and after processing. Preferably it is 5N or more, More preferably, it is 7N or more, More preferably, it is 9N or more.
It is preferable that the average value of the distance between the fiber entanglement points of the natural product-derived fiber is 400 μm or less. If the average value of the distance between the entanglement points exceeds 400 μm, the three-dimensional entanglement of the fibers is insufficient and the tensile strength is insufficient, which may cause troubles such as tearing during sheet production or processing. The distance between fiber entanglement points is preferably 350 μm or less, more preferably 300 μm or less.

In the nonwoven fabric of the present invention, for example, after forming a fiber sheet containing fibers derived from natural products, the fibers are three-dimensionally entangled by fluid flow treatment so that the average value of the distance between the fiber entanglement points is 400 μm or less. It can manufacture with the manufacturing method of the nonwoven fabric characterized by including a process.
In order to prepare the nonwoven fabric of the present invention, a wet method is usually used as a method for forming a fiber sheet.
The nonwoven fabric of the present invention is obtained by the following production method, but the production method is not particularly limited.

When the wet method is used, the length of the short fiber is preferably 20 mm or less, and the ratio L / D of the short fiber length (L) to the single fiber diameter (D) satisfies 300 to 2000. Disperse the short fibers of a specific shape in water to a concentration of 0.1 to 3%, and prepare a slurry. At this time, it is preferable to add a small amount of a dispersant. A papermaking sheet is prepared from this slurry by a papermaking machine such as a long net type or a round net type. In the case of the dry method, the fiber length is preferably 20 mm or more, and a fiber satisfying L / D of 1000 to 5000 is formed into a sheet by a card method, a cross wrapper method, a method in which both are combined, or the like.
Next, the obtained sheet is tangled with the short fibers by a known method such as high-speed fluid flow treatment, needle punching, stitch bonding or the like.

Hereinafter, the high-speed fluid processing method will be described in detail.
In the case of performing high-speed fluid treatment, liquid or gas can be used as the fluid, but water is most preferable from the viewpoints of ease of handling, cost, impact energy, and the like. When water is used, the water pressure varies depending on the type of fiber used, the basis weight of the sheet, and the processing speed, but is preferably set to 1 to 25 MPa in order to sufficiently entangle the water. More preferably, it is 2-20 MPa. The diameter of the nozzle that ejects the water flow is preferably 0.05 to 0.5 mm. It is preferable to arrange so that the interval between the nozzle holes is 0.2 to 10 mm. In order to effectively entangle and reduce the distance between the entanglement points, it is also important to remove water sprayed on the sheet.

  As a method, it is preferable to place a support such as a fine wire net under the sheet and perform suction dehydration from the bottom. The trajectory shape of the water flow may be a straight line parallel to the traveling direction of the sheet, or the head mounted with the nozzle is rotated or reciprocated perpendicularly to the traveling direction of the sheet. Although the curved shape obtained may be used, the curved trajectory obtained by the rotational movement or reciprocating movement of the header increases the water injection area to the sheet per nozzle weight, and reduces the interfiber distance. Is effective, and at the same time, the curved trajectory is preferable in that it is difficult to see the water trajectory without impairing the excellent uniformity of the sheet. In this case, the water pressure may be changed. If a method of gradually increasing the water pressure with a weak water pressure is adopted at the beginning, the movement of the yarn forming the sheet is reduced in the front-rear and left-right directions, and a uniform nonwoven fabric can be obtained. . The initial water pressure is preferably 80% or less of the maximum process water pressure, more preferably 70% or less.

  The order of applying the water flow to the sheet may be the method of alternately applying the front or back, or the method of applying only to one side. However, if the distance between the fibers is to be reduced and a uniform surface is to be obtained, the front and back are processed alternately. It is good. Changing the water pressure stepwise is also effective in reducing the distance between fibers and making it difficult to see the trajectory of the water flow and obtaining a flat and uniform surface. The sheet or nonwoven fabric obtained by entanglement in this way, the fibers are bonded to each other with an adhesive or resin, or the glass transition temperature of the thermoplastic fiber other than the fiber derived from the mixed natural product, the temperature below the melting point May be heated to fuse the fibers together. As the adhesive and adhesive resin, known ones such as epoxy resin, silicon resin, acrylic resin, melamine resin, unsaturated polyester resin, urethane resin, urea resin, phenol resin, formalin, glyoxal can be used. When the thermoplastic fiber is heat-sealed, it is preferably heated to 100 ° C. to the melting point of the thermoplastic fiber, and (melting point−30 ° C.) of the thermoplastic fiber to (melting point−10 ° C. of the thermoplastic fiber is more preferable.

Further, the obtained nonwoven fabric may be further subjected to surface modification or post-processing treatment as necessary. In the surface modification, for example, a known method such as chemical modification by bringing a fiber derived from a natural product into contact with a reactive compound or physical modification by electron beam or plasma treatment can be employed. Specifically, for example, ammonia, diethylamine, ethylenediamine, ethylamine, polyalkylamine, aminopyridine, aminoalkylpyridine, alkylaniline, alkylaminobenzoate, amine compounds such as epoxyamine, oxime compounds such as ethylene oxide, ethylene oxide glycidyl ether, A method of reacting with a compound such as sulfuric acid such as sulfuric acid or sulfurous acid, a method of reacting with a vinyl compound or oxime compound such as vinyl acetate, allylsulfonic acid, styrene or styrenesulfonic acid after electron beam irradiation, sodium borohydride or ruthenium compound And the like, and a method of hydrogenation by contacting with hydrogen as a catalyst.

The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
The measuring method of each measured value used in the present invention is as follows.
(1) Specific surface area: Measured by a BET adsorption method using a tristar 3000 manufactured by Shimadzu Corporation and using an adsorption gas of nitrogen.
(2) Fabric weight: Measured according to JIS-L-1096.

(3) Thickness: Measured with a thickness meter (Peacock Co., Ltd .: Model H) at a constant measurement area (circular area of 10 mm in diameter) at four locations on the test piece, and the average value is the thickness. It was.
(4) Tensile strength: Based on the strip method of JIS-L-1096, the tensile strength of each of the vertical (sheet traveling direction) and the horizontal (sheet width direction) was measured.

(5) Tear strength: Based on the strip method of JIS-L-1096, each tear strength was measured.
(6) Penetrating strength: A stainless steel jig (a blade thickness of 0.3 mm, a scraper cutter blade manufactured by OLFA) in which one test piece of 20 cm × 2.5 cm is attached to a handy compression tester (manufactured by Kato Tech, KES-G5) Was cut vertically at a speed of 25 mm / sec, and the force required to cut the nonwoven fabric (penetration strength) was measured.

(7) Distance between entanglement points: Measured with a scanning electron microscope at a magnification of 100, and an average value of 50 pieces was taken. The distance between the entanglement points here is a value measured by a known method described in Japanese Patent Publication No. 58-191280, and is one measure showing the entanglement density between fibers. The smaller this value, the denser the entanglement. FIG. 1 is an enlarged schematic view when the constituent fibers in the nonwoven fabric sheet according to the present invention are observed from the surface. The constituent fibers are f ₁ , f ₂ , f ₃ ..., And a point where any two fibers f ₁ and f ₂ are entangled is a ₁ , and the upper fiber f ₂ is another fiber. will follow until the point of intersection in the form of the bottom, to the point where the the intersection with a _2. Similarly, a ₃ , a ₄ . Next, the horizontal horizontal distances a _{1 to} a ₂ , a _{2 to} a ₃ ... Between the entanglement points obtained in this way are measured, an average value of these many measurement values is obtained, and this is calculated between the entanglement points. Distance.

(Reference Example 1)
The fibers derived from the natural materials of the nonwoven fabric raw materials shown in Examples 1 to 11 of the present invention were each produced according to a production method combining rough defibration and fine defibration described in Japanese Patent Application No. 2003-435317. That is, the bamboo fibers of Examples 1 and 3 and Examples 9 to 11 were obtained by compressing and cleaving bamboo materials at room temperature, then roughing and then finely opening at the same temperature. On the other hand, the bamboo fiber of Example 2 was obtained by steaming bamboo material with high-temperature and high-pressure steam in advance, rough defibration at a temperature higher than normal temperature under normal pressure, and then fine defibration. The cedar, straw, pine, kenaf, sugar cane, and pineapple fiber of Examples 4 to 8 were produced by the same manufacturing method as the bamboo fiber of Example 2.

[Example 1]
The bamboo fiber short fibers (length 10 mm, short yarn diameter 0.3 mm, specific surface area 0.7 m ² / g, polymerization degree 450) obtained in Reference Example 1 were dispersed in water to give a 1 wt% slurry. This slurry was made with an inclined long net making machine to obtain a sheet having a basis weight of 45 g / m ² .
This sheet is placed on an 80-mesh wire mesh, and a header equipped with nozzles having a nozzle diameter of 0.15 mm, a nozzle pitch of 5 mm, and a number of rows of 5 rows is treated at an initial water pressure of 5 MPa while circularly moving at 140 rpm, and then at a water pressure of 10 MPa. Short fibers were entangled by causing the jet water to collide with the sheet. This treatment was repeated three times for each of the front and back sides. Subsequently, the water pressure was set to 4 MPa, and the front and back surfaces were treated once. Then, it dried at 100 degreeC and obtained the nonwoven fabric. Table 1 shows the properties of the obtained nonwoven fabric.
The nonwoven fabric thus obtained showed excellent mechanical properties and antibacterial properties against Escherichia coli.

[Example 2]
A sheet having a weight per unit area of 46 g / m ² was obtained in the same manner as in Example 1 except that the short bamboo fiber having a changed shape was changed to a short fiber having a length of 5 mm and a short yarn diameter of 0.03 mm.
From this sheet, others were processed in the same manner as in Example 1 to obtain a nonwoven fabric. Table 1 shows the physical properties of the nonwoven fabric.
[Example 3]
Example 1 was repeated by mixing 80% by weight of bamboo fiber and 20% by weight of polyethylene terephthalate fiber (PET fiber) having a single yarn fineness of 0.3 cN / dtex and a fiber length of 3 mm. Improvement in mechanical properties was observed. Table 1 shows the properties of the obtained nonwoven fabric.

[Examples 4 to 8]
Example 1 was repeated using fibers derived from other natural products instead of bamboo fibers. The properties of the obtained nonwoven fabric are summarized in Table 1.
[Example 9]
In the manufacturing process of the nonwoven fabric of Example 1, after being dipped in an adhesive aqueous solution composed of a self-crosslinking acrylic resin and a melamine resin before drying, after passing through a nip roll and drying at 110 ° C., a thermosetting treatment is subsequently performed at 200 ° C. The nonwoven fabric was obtained. Table 1 shows the properties of the obtained nonwoven fabric.

[Example 10]
The nonwoven fabric of Example 1 was heat-treated at 250 ° C. for 15 minutes. The obtained non-woven fabric was slightly blackish and had a tasteful color with the impression of withering.
[Example 11]
The nonwoven fabric of Example 1 was baked at 1000 ° C. for 12 hours to obtain a bamboo charcoal nonwoven fabric. The obtained non-woven fabric was useful for deodorizing effect and deodorizing tap water.

[Comparative Example 1]
Blasting-treated bamboo fibers (length 10 mm, short yarn diameter 0.3 mm, specific surface area 0.7 m ² / g, polymerization degree 350) were made into a nonwoven fabric in the same manner as in Example 1. The penetration strength was insufficient (Table 1).
[Comparative Example 2]
Except for using a short fiber length (L / D = 40) having a length of 2 mm, a short yarn diameter of 0.05 mm, a specific surface area of 0.7 m ² / g, and a polymerization degree of 350, a basis weight of 41 g / A non-woven fabric of m ² was obtained. This nonwoven fabric had insufficient penetration strength (Table 1). In addition, the bamboo fibers fell off when rubbed.

  The non-woven fabric according to the present invention has mechanical characteristics equal to or higher than those of synthetic fibers, and takes advantage of the natural feeling of natural products, various packaging materials, wallpaper, roofing base cloth, rust-proof tape, and reinforcement of each cable. Reinforcement materials such as materials, presser rolls, wear plates, concrete reinforcements, various wear cloths, isolation membranes, separation membranes, separator clothing members, disposable clothing, shoe members, and protective applications such as protective clothing and protective equipment, Medical use such as surgical clothes, masks, hap material base fabrics, roofing, tuft / carpet base fabrics, anti-condensation sheets, reinforcement materials, protective materials, repair materials for underground pipes, automobile interiors, automotive parts, etc. Vehicle applications, emergency supplies, cleaning products, towels, carpets, furniture components, wallpaper and other furniture and interior applications, wet wipers, cleaning materials, air filters, bag filters Electret filters, water treatment filter applications, bedding, futon bags, pillow cover, etc., bedding sheets, grass protection sheets, garden planters, storage products, packaging materials, kitchen materials, etc. It can be used for product materials, equipment members, etc.

It is an expansion schematic diagram when the constituent fiber in the nonwoven fabric sheet by this invention is observed from the surface.

Claims (9)

A nonwoven fabric characterized by three-dimensional entanglement of fibers containing fibers derived from natural products, a basis weight of 5 to 500 g / m ² , and a penetration strength of 4N or more. The specific surface area of the fiber derived from a natural product is 0.05-50 m < ² > / g, The nonwoven fabric of Claim 1 characterized by the above-mentioned.   The content rate of the fiber derived from a natural product is 50 wt% or more, and the content rate of a synthetic fiber and / or a reproduction | regeneration fiber is less than 50%, The nonwoven fabric of Claim 1 or 2 characterized by the above-mentioned.   4. The nonwoven fabric according to claim 1, wherein the fibers constituting the nonwoven fabric are three-dimensionally entangled, and an average value of the distance between the fiber entanglement points is 400 μm or less.   The nonwoven fabric according to any one of claims 1 to 4, wherein three-dimensionally entangled fibers are bonded with an adhesive or a heat-fusible resin.   A nonwoven fabric characterized in that the nonwoven fabric according to claim 1 is heated and partially or completely carbonized.   The non-woven fabric according to any one of claims 1 to 6, wherein the fiber derived from a natural product is at least one fiber selected from bamboo, cedar, bamboo shoot, pine, kenaf, sugar cane, and pineapple. .   The single yarn diameter of the fiber derived from a natural product is 1 μm to 2 mm, the ratio L / D of the fiber length L to the single yarn diameter D is 50 to 10,000, and the fiber diameter is 0.001 to 0 of the fiber diameter on the fiber surface. The non-woven fabric according to any one of claims 1 to 7, wherein there is fibril peeling corresponding to 2 times.   After forming a fiber sheet containing fibers derived from natural products, the fibers are three-dimensionally entangled by fluid flow treatment, and the average value of the distance between the fiber entanglement points is 400 µm or less. The manufacturing method of the nonwoven fabric as described in any one of 8.

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