JP2023182007A - Nonwoven fabric and nonwoven fabric manufacturing method - Google Patents

Abstract

To provide a nonwoven fabric containing cellulosic fibers, which achieves softness of nonwoven fabric feeling and suppresses fluff and can be used for a product to directly come in contact with human skin, such as an absorbent article, and a manufacturing method of the nonwoven fabric.SOLUTION: A nonwoven fabric contains cellulosic fibers and adhesive fibers, includes bonded parts between the adhesive fiber and the cellulosic fiber and/or the adhesive fiber, and includes entangled parts between the cellulosic fiber and the cellulosic fiber and/or the adhesive fiber. Bonding intersection index A of the nonwoven fabric is 1 to 60 points/mm2 or thickness reduction rate of the nonwoven fabric is 30 to 45%.SELECTED DRAWING: None

Description

The present invention relates to a nonwoven fabric and a method for manufacturing the nonwoven fabric.

Nonwovens are used, for example, in absorbent articles such as disposable diapers, sanitary napkins, incontinence pads, and panty liners. Since cellulose fibers have excellent hygroscopicity and are renewable fibers derived from plants, nonwoven fabrics containing cellulose fibers are of interest from the perspective of reducing the burden on the natural environment.
Nonwoven fabrics containing cellulose fibers do not sufficiently suppress fluff, so for example, nonwoven fabrics that have undergone hydroentangling, and nonwoven fabrics that have constituent fibers bonded together by heat fusion of heat-fusible fibers are used. There is.
However, the former has a hard texture, and the latter still has a problem in that it does not sufficiently suppress fluff.
Therefore, nonwoven fabrics containing cellulose fibers are not used for applications that come in direct contact with human skin, and are used in absorbent materials such as absorbent articles that do not come into direct contact with human skin, where fuzz control and soft texture are not important. (See Patent Document 1).

Japanese Patent Application Publication No. 2002-159533

The present invention provides a nonwoven fabric containing cellulose fibers that can be used for applications that come into direct contact with human skin, such as absorbent articles, which have both a soft texture and suppressed fuzz, and a method for producing the nonwoven fabric. It was done for that purpose.

The present inventors have developed a nonwoven fabric containing both cellulose fibers and adhesive fibers, including areas where the fibers are bonded to each other by the adhesive fibers and areas where the fibers are intertwined, and further adjust specific physical properties of the nonwoven fabric. The present inventors have now completed the present invention by discovering that at least one of the suppression of fuzz and the softness of the texture, preferably both, can be improved.
Furthermore, when manufacturing a nonwoven fabric containing both cellulose fibers and adhesive fibers, the present inventors achieved a soft texture and suppressed fuzz by adhering the fibers together in advance and then interlacing the fibers. The present invention was completed by discovering that it is possible to obtain a nonwoven fabric that achieves both of the following.

That is, in one gist of the present invention,
A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined part of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
The nonwoven fabric has an adhesive intersection index A of 1 to 60 pieces/mm ² or a thickness reduction rate of 30 to 45%.
The nonwoven fabric of the present invention can be used, for example, in applications that come into direct contact with human skin, such as absorbent articles.

Moreover, the present invention, in another gist,
A method for producing a nonwoven fabric containing cellulose fibers and adhesive fibers, the method comprising: an adhesion step of adhering fibers to each other using the adhesive fibers; and an entangling step of intertwining the fibers after the adhesion step. A manufacturing method is provided.

Since the nonwoven fabric of the present disclosure has the above-mentioned characteristics, it has both suppressed fuzzing and soft texture, and can be used for applications that come into direct contact with human skin, such as absorbent articles, for example.

FIG. 1 shows a SEM image of a cross section of the nonwoven fabric of Example 31 cut in the longitudinal direction. The magnification is 60x. FIG. 2 shows a SEM image of a cross section of the nonwoven fabric of Comparative Example 50 cut in the transverse direction. The magnification is 25 times. FIG. 3 shows a SEM image of a cross section of the nonwoven fabric of Example 31 cut in the transverse direction. The magnification is 100x. FIG. 4 shows a SEM image of the surface of the nonwoven fabric of Example 31. The magnification is 100x. FIG. 5 shows a SEM image of the back side of the nonwoven fabric of Example 31. The magnification is 100x.

The nonwoven fabric of the form of the present invention is
A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined part of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
(i) the adhesive intersection index A of the nonwoven fabric is 1 to 60 pieces/mm ² , or (ii) the thickness reduction rate of the nonwoven fabric is 30 to 45%,
It is a non-woven fabric.
The nonwoven fabric of the present invention is suitable for use in skin-contact products such as absorbent articles that come into direct contact with human skin (for example, top sheets and back sheets for absorbent articles, liquid-impregnated skin products impregnated with liquids such as cosmetics, etc.). Covering materials (e.g., face masks, keratin care sheets, decolletage sheets, etc.), base fabrics for various poultices including hot and cold compresses, personal wipes (e.g., cleansing sheets, antiperspirant sheets, and decollete sheets, etc.) It can be used for bacteria sheets, etc.).

(cellulose fiber)
In the nonwoven fabric of the present invention, "cellulose fiber" is also called cellulose fiber, and generally refers to fiber made from cellulose.
Cellulosic fibers are natural fibers derived from plants such as cotton, hemp, linen, ramie, jute, banana, bamboo, kenaf, shellfish, hemp, and kapok; obtained by the viscose method. Regenerated fibers such as rayon and polynosic rayon, cupro obtained by the copper ammonia method, and Tencel (registered trademark) and Lyocell (registered trademark) obtained by the solvent spinning method; cellulose fibers obtained by the melt spinning method; and acetate fibers, etc. There is no particular restriction as long as the nonwoven fabric contains semi-synthetic fibers and can obtain the nonwoven fabric targeted by the present invention.

The fineness of the cellulose fiber is preferably 0.6 to 5.6 dtex, more preferably 1.0 to 4.4 dtex, and even more preferably 1.4 to 3.3 dtex.
When the fineness of the cellulose fiber is within the above range, it is preferable because the fineness is not too small and the strength of the nonwoven fabric is more suitable, and the fineness is not too large and the texture of the nonwoven fabric is more suitable. . In addition, when the fineness of the cellulose fibers is within the above range, the entangling properties of the fibers are more suitable, and since the entangling properties of the nonwoven fabric are not too low, the strength and fluff of the nonwoven fabric are more suitable, and the entangling properties of the nonwoven fabric are not too low. It is preferable that the texture of the nonwoven fabric is not too high because the texture of the nonwoven fabric is more suitable.

The fiber diameter of the cellulose fiber is preferably 5 to 25 μm, more preferably 8 to 20 μm, and even more preferably 10 to 17 μm.
When the fiber diameter of the cellulose fiber is within the above-mentioned range, the strength of the nonwoven fabric will be more suitable if the fineness is not too small, and the texture of the nonwoven fabric will be more suitable if the fineness is not too large. preferable. In addition, when the fineness of the cellulose fibers is within the above range, the entangling properties of the fibers are more suitable, and since the entangling properties of the nonwoven fabric are not too low, the strength and fluff of the nonwoven fabric are more suitable, and the entangling properties of the nonwoven fabric are not too low. It is preferable that the texture of the nonwoven fabric is not too high because the texture of the nonwoven fabric is more suitable.

The fiber length of the cellulose fiber is preferably 25 to 100 mm, more preferably 30 to 70 mm, and even more preferably 35 to 60 mm.
It is preferable that the fiber length of the cellulose fibers is within the above-mentioned range because the intertwining properties of the fibers are suitable. In particular, the nonwoven fabric of the present disclosure can be manufactured by once adhering the constituent fibers to each other using adhesive fibers and then performing an interlacing treatment, so that the fiber length is not too large, so that the adhesion location in one fiber is more appropriate. This is preferable because the fibers can be more suitably intertwined to the extent that fuzz can be sufficiently suppressed. In addition, it is preferable that the fiber length is not too small because the number of bonding points in one fiber becomes more appropriate, and the fibers can be intertwined more appropriately to the extent that the texture of the nonwoven fabric can be sufficiently softened.

The fiber cross section (cross section or cross section perpendicular to the length direction of the fibers) of the cellulose fibers may be circular or non-circular, and examples of non-circular shapes include ellipsoids and Y-shapes. , X-shaped, I-shaped, multilobed, polygonal, star-shaped, chrysanthemum-shaped, etc. When the cross section of the fibers is circular, the area where the fibers adhere to the adhesive fibers is relatively small, so that the softness of the nonwoven fabric can be improved. When the cross-section of the fibers is non-circular, the area of adhesion with the adhesive fibers is relatively large, which may result in better fuzz control of the nonwoven fabric or higher tenacity of the nonwoven fabric.

The cellulose-based fibers are preferably chemical fibers such as regenerated fibers and semi-synthetic fibers. Chemical fibers are more preferable because they can further reduce variations in fineness and/or fiber diameter and fiber length, and can more easily adjust the degree of entanglement of the nonwoven fabric. In addition, rayon, solvent-spun cellulose fibers, and the like are preferable because the fibers themselves have a good balance of softness and strength when wet, and it is easier to obtain softness and strength with a suitable texture as a nonwoven fabric. Furthermore, since solvent-spun cellulose fibers have relatively high single fiber tenacity, they are preferable in that they suppress fluffing of the nonwoven fabric and improve the tenacity of the nonwoven fabric.
Cellulosic fibers can be used alone or in combination.

Cellulosic fibers may be surface treated to change the degree of hydrophilicity or hydrophobicity of their surfaces. Generally, the degree of hydrophilicity or hydrophobicity of the surface of cellulose fibers can be changed using an oil agent (surfactant). The degree of hydrophilicity or hydrophobicity can be evaluated using, for example, values such as the sedimentation rate of fibers. The surface of cellulose fibers may be hydrophilic or hydrophobic. The value of the sedimentation velocity (or sedimentation time (sec)) of the fibers may be, for example, 30 seconds or less, more preferably 20 seconds or less, and still more preferably 10 seconds or less. If the settling rate (or settling time) of the cellulosic fibers is small, the entangling properties of the cellulosic fibers will be relatively good, the fluffing control of the nonwoven fabric may be better, or the tenacity of the nonwoven fabric may be greater.

The sedimentation rate of fibers can be measured by the following method.
Collect 17 g of fiber whose sedimentation rate is to be measured. The collected fibers are opened (using a parallel carding machine) to form a carded web. Weigh 5 g of the carded web and fill it into a basket (cylindrical shape with a diameter of 5 cm and a height of 8 cm; the weight of the basket body is 3 g) made of copper wire (thickness: 0.55 mm).
Next, prepare a constant temperature water tank, fill it with tap water, and set it to 25°C. When the water temperature reaches 25°C, stop stirring the constant temperature water bath and start measuring the sedimentation rate. Gently drop the fiber-filled basket using the above procedure from a position of 1 cm above the water surface, and start the stopwatch as soon as the basket falls to the water surface. The fibers gradually become hydrated and the stopwatch is stopped at the same time that the 8cm high basket is completely submerged under the water. The time from when the basket falls to the water surface until the basket sinks below the water surface is defined as the sedimentation velocity, and the average value of the two measurements is defined as the sedimentation velocity of the fiber.

In the above sedimentation rate measurement, if the basket does not sink below the water surface for 5 minutes or more, the fiber is considered to be water repellent. If the cellulosic fiber is water repellent, it may be preferred in applications where the nonwoven fabric is brought into contact with liquid. For example, in top sheets and second sheets for absorbent articles, it is sometimes preferable that the cellulose fibers are water repellent because this makes it easier to transfer liquid to the absorbent body without retaining too much liquid in the sheet. In addition, when a nonwoven fabric has a laminated structure, if a laminated nonwoven fabric that has a layer containing water-repellent cellulose fibers and a layer containing cellulose fibers that are not water-repellent is used, it is difficult to absorb liquids such as sheets for absorbent articles or cosmetics. In liquid-impregnated skin dressing applications, the nonwoven fabric may suitably transport or retain liquid.

(Adhesive fiber)
In the nonwoven fabric of the present invention, "adhesive fibers" exhibit adhesive properties by adhesion treatment (e.g., thermal adhesion treatment, electron beam irradiation, ultrasonic welding, etc.) and bond fibers together. It refers to fibers that can be used to form adhesion points, and is not particularly limited as long as the nonwoven fabric targeted by the present disclosure can be obtained.

The adhesive fibers include, for example, synthetic fibers made of thermoplastic resin.
The thermoplastic resin is not particularly limited as long as the nonwoven fabric targeted by the present invention can be obtained, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof. Polyester resins such as polymers; polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene copolymer whose main component is propylene (propylene-ethylene copolymer) Polyolefin resins such as polymers, propylene-butene-1-ethylene copolymers), ethylene-acrylic acid copolymers, and ethylene-vinyl acetate copolymers; polyamides such as nylon 6, nylon 12, and nylon 66 Resin; Acrylic resin; Engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefin, and their elastomers can be exemplified, and any material can be selected from these.

The adhesive component of the adhesive fiber is preferably a copolymer of an olefin and an unsaturated carboxylic acid or a derivative thereof from the viewpoint of good adhesion to the cellulose fiber. Examples of unsaturated carboxylic acids include maleic acid, acrylic acid, methacrylic acid, fumaric acid, and itaconic acid. Examples of derivatives thereof include anhydrides of unsaturated carboxylic acids, methyl methacrylate, ethyl methacrylate, and 2-methacrylic acid. Methacrylic esters such as hydroxyethyl, dimethylaminoethyl methacrylate, or similar acrylic esters, glycidyl acrylate, glycidyl methacrylate, butene carboxylic esters, allyl glycidyl ether, 3,4-epoxybutene, 5,6- Examples include epoxy-1-hexene and vinylcyclohexene monoxide. Particularly preferred is an ethylene-acrylic acid copolymer in which the olefin is ethylene and the unsaturated carboxylic acid or its derivative is acrylic acid.

The synthetic fiber may be a single fiber made of one or more thermoplastic resins selected from the above, or may be a composite fiber made of two or more components (also referred to as "sections"). In the composite fiber, each component may be made of one thermoplastic resin, or may be a mixture of two or more thermoplastic resins. The composite fiber may be, for example, a core-sheath type composite fiber, an island-in-the-sea type composite fiber, or a side-by-side type composite fiber. The core-sheath type composite fiber may be an eccentric core-sheath type composite fiber in which the center of the core component and the center of the sheath component do not coincide in the fiber cross section, and may be an eccentric core-sheath type composite fiber in which the center of the core component and the center of the sheath component coincide in the fiber cross section. It may be a sheath type composite fiber.

Synthetic fibers, whether monofilament or composite fibers, may have irregular cross-sections. In the case of a core-sheath type conjugate fiber and a sea-island type conjugate fiber, the core component and/or the island component may have an irregular cross section in the fiber cross section.
When the synthetic fiber has an irregular cross section, the cross section may be an ellipse, a polygon, a star, or a shape in which a plurality of convex portions are joined at the base (for example, a clover shape).
In this embodiment, two or more synthetic fibers may be used in combination as the synthetic fibers.

When the synthetic fiber is a composite fiber, two or more components may be arranged so that a thermoplastic resin with a lower melting point forms part of the fiber surface. A thermoplastic resin with a low melting point (low melting point component) melts or softens when heat is applied in the process of producing a nonwoven fabric, and becomes an adhesive component. The low melting point component can contribute to adhesion of fibers to each other or to other members, and can form bonding points.
When the synthetic fiber is a composite fiber, it is preferable that the low melting point component is exposed in the cross section of the fiber over a length of 50% or more of the length of the peripheral surface of the fiber, and a length of 60% or more of the length of the peripheral surface of the fiber. It is more preferable that the length of the fiber is exposed, more preferably that 80% or more of the length is exposed, and it is particularly preferable that the entire circumferential surface of the fiber is exposed.

The nonwoven fabric according to the present invention can be produced by adhering fibers together in advance and then entangling the fibers with each other. Therefore, the area where the low melting point component of the adhesive fiber is exposed on the fiber peripheral surface in the fiber cross section is not too small, so there is a more appropriate area where bonding is possible, and the number of bonding points between fibers is more appropriate. Therefore, the adhesion strength at the adhesion point between the fibers becomes more appropriate, and the adhesion by the adhesive fibers can be made more sufficient. Therefore, the prevention of fuzz of the nonwoven fabric and the strength of the nonwoven fabric can be made more suitable. Furthermore, in the subsequent entanglement, the degree to which the adhesion between the fibers is resolved becomes more appropriate, and the fluffing of the nonwoven fabric can be suppressed and the strength of the nonwoven fabric can be made more sufficient. In particular, the nonwoven fabric of this embodiment contains cellulose fibers, and the adhesiveness between the cellulose fibers and the adhesive fibers is not high, and the elimination of adhesion points between the fibers is further promoted, so that the nonwoven fabric is less fluffy and strong. The impact could be even greater.

Combinations of thermoplastic resins constituting composite fibers include, for example, combinations of polyolefin resins and polyester resins such as polyethylene/polyethylene terephthalate, polypropylene/polyethylene terephthalate, and propylene copolymer/polyethylene terephthalate (polyolefin resin/polyester resin). combinations of two types of polyolefin resins (polyolefin resins/polyolefin resins) such as polyethylene/polypropylene, propylene copolymer/polypropylene, ethylene-acrylic acid copolymer/polypropylene, and two types of polyolefin resins with different melting points. Contains combinations of different types of polyester resins (polyester resin/polyester resin).

Note that the thermoplastic resin illustrated as a component of the single fiber or composite fiber may contain other components as long as it contains 50% by mass or more of the specifically indicated thermoplastic resin. For example, in the combination of polyethylene/polyethylene terephthalate, "polyethylene" may contain other thermoplastic resins, additives, etc. as long as it contains 50% by mass or more of polyethylene. This also applies to the following examples.

When the adhesive fiber is a core-sheath composite fiber in which the sheath is made of a thermoplastic resin with a lower melting point, the core/sheath combination may be, for example, polyethylene terephthalate/polyethylene, polyethylene terephthalate/polypropylene, polyethylene terephthalate/propylene. Copolymers, polytrimethylene terephthalate/polyethylene, polybutylene terephthalate/polyethylene, polyethylene terephthalate/copolyester (for example, polyethylene terephthalate copolymerized with isophthalic acid), and polypropylene/ethylene-acrylic acid copolymers. A core-sheath composite fiber whose sheath is made of polyethylene (e.g., high-density polyethylene, low-density polyethylene, or linear low-density polyethylene) or copolymer polyester is heat-treated at a temperature higher than the melting point of the thermoplastic resin constituting the sheath. By doing so, the sheath melts or softens, and has the property of adhering the fibers to each other to form a bonding point.

When the adhesive fiber is a core-sheath composite fiber, the core-sheath composite ratio (volume ratio, core/sheath) may be, for example, 80/20 to 20/80, particularly 60/40 to 40/60. It may be.
If the proportion of the sheath is not too small, the adhesion between the fibers will be more sufficient, and the suppression of fuzz may be more suitable, or the strength of the nonwoven fabric may be more suitable. In addition, the peeling of the bonded area during intertwining becomes more appropriate, and furthermore, the suppression of fluffing becomes more suitable, or the strength of the nonwoven fabric becomes more suitable. When the proportion of the sheath is not too large, the proportion of the core component that maintains the fiber shape becomes more sufficient, and the strength of the nonwoven fabric can be made more suitable.

The adhesive fiber includes two or more fibers, and the adhesive components of the fibers may have different melting points. For example, the adhesive fiber may include two fibers, and the difference in melting point of the adhesive components of these fibers may be 10°C or more and 40°C or less, and further may be 15°C or more and 30°C or less.

The fineness of the adhesive fiber is preferably 1.0 to 7.8 dtex, more preferably 1.4 to 6.7 dtex, and even more preferably 2.2 to 4.5 dtex.
When the fineness of the adhesive fiber is within the above range, the strength of the nonwoven fabric is further improved and the texture of the nonwoven fabric is softer, which is preferable.

The fiber diameter of the adhesive fiber is preferably 10 to 33 μm, more preferably 12 to 30 μm, and even more preferably 15 to 25 μm.
When the fiber diameter of the adhesive fiber is within the above range, the strength of the nonwoven fabric is further improved and the texture is softer than that of a nonwoven fabric, which is preferable.

The fiber length of the adhesive fiber is preferably 25 to 100 mm, more preferably 30 to 70 mm, and even more preferably 35 to 60 mm.
It is preferable that the fiber length of the adhesive fiber is within the above-mentioned range because the intertwining properties of the fibers become more suitable. In particular, the nonwoven fabric of the present disclosure can be manufactured by once adhering constituent fibers to each other using adhesive fibers and then performing an interlacing treatment. Therefore, since the fiber length is not too large, the number of adhesion points in one fiber becomes more appropriate, and the intertwining properties of the fibers can be made more suitable to the extent that fuzz can be more fully suppressed. Furthermore, since the fiber length is not too short, the number of adhesion points in one fiber becomes more appropriate, and the intertwining properties of the fibers can be made more suitable to the extent that the texture of the nonwoven fabric can be made more sufficiently soft.

Preferably, the adhesive fiber has three-dimensional crimp. The term "three-dimensional crimp" is used herein to distinguish from mechanical crimp, where the crests (or crests) of the crimp are at acute angles. Three-dimensional crimp includes, for example, crimp with curved peaks (wave-shaped crimp), crimp with spirally curved peaks (spiral crimp), and a mixture of wave-shaped crimp and spiral crimp. This refers to crimps that are a mixture of sharp crimps, mechanical crimps, and at least one of wave-shaped crimps and spiral crimps. The adhesive fibers may have mechanical crimps.
When the adhesive fiber is a conjugate fiber, it may be an overtly crimpable conjugate fiber. "Expected crimp composite fiber" refers to a fiber that exhibits three-dimensional crimp at the fiber stage. The actual crimpable composite fiber is different from the latent crimpable composite fiber, which develops three-dimensional crimp through heat treatment accompanied by fiber contraction.

When the adhesive fiber is an eccentric core-sheath type composite fiber, the eccentricity is preferably 5 to 50%, more preferably 7 to 30%. The eccentricity here is defined by the following equation.
(Formula) Eccentricity (%) = (distance between the center of the single fiber and the center of the core component) x 100/(radius of the single fiber)
When the adhesive fiber has three-dimensional crimp, the adhesive intersection index A of the nonwoven fabric, the thickness reduction rate of the nonwoven fabric, the bending resistance per unit thickness of the nonwoven fabric, the thickness ratio of the nonwoven fabric, the thickness direction of the nonwoven fabric, which will be described later. A nonwoven fabric exhibiting a value within a specific range with respect to the angle of the fiber bonding point in the middle when divided into three equal parts can be more easily obtained, which is more preferable.
Adhesive fibers can be used alone or in combination.

In the nonwoven fabric of the present invention, the blend ratio of cellulose fibers and adhesive fibers (cellulose fibers: adhesive fibers) (mass ratio) is preferably 10:90 to 90:10, and preferably 25:75 to 25:75. The ratio is more preferably 75:25, and even more preferably 35:65 to 65:35.
When the blend ratio of cellulose fibers and adhesive fibers (cellulose fibers: adhesive fibers) (mass ratio) is within the above range, both the softness of the texture and the suppression of fuzz of the nonwoven fabric can be further improved, preferable.
Furthermore, when cellulose fibers are included in an appropriate amount, the effects of cellulose fibers can be more easily obtained.
In addition, when a suitable amount of cellulose fibers are included, the fibers can be entangled with each other more easily. It is preferable because it is possible to more easily obtain a nonwoven fabric exhibiting values in a specific range with respect to the thickness ratio of the nonwoven fabric, the angle of the fiber adhesion point in the middle when the nonwoven fabric is divided into three equal parts in the thickness direction.
In addition, it is preferable that adhesive fibers are contained in an appropriate amount, since both the suppression of fuzz of the nonwoven fabric and the softness of the texture of the nonwoven fabric are further improved.
In the nonwoven fabric of the present invention, if the adhesive fiber content is 35% by mass or more, the nonwoven fabric or the intermediate fiber web may be broken or stretched more than necessary during transportation during nonwoven fabric production. This is preferable because it can be easily prevented.

The nonwoven fabric of this embodiment may contain fibers other than cellulose fibers and adhesive fibers (hereinafter referred to as "other fibers"). Other fibers include, for example, natural fibers that are not cellulose fibers (e.g., wool, silk, etc.), synthetic fibers that are not adhesive fibers (e.g., do not melt or soften when the adhesive component of adhesive fibers is melted, and have adhesive properties. (synthetic fibers, etc. that do not exhibit the above), and there are no particular restrictions as long as the nonwoven fabric aimed at by the present invention can be obtained.
Other fibers may be contained in a proportion of 35% by mass or less, particularly 25% by mass or less, more particularly 10% by mass or less, as long as the nonwoven fabric targeted by the present invention can be obtained. There are no particular restrictions. The nonwoven fabric of this embodiment may be a nonwoven fabric that does not contain other fibers, that is, a nonwoven fabric that is made of cellulose fibers and adhesive fibers.

In the nonwoven fabric of this embodiment, the fibers are bonded to each other by adhesive fibers. That is, the nonwoven fabric according to the embodiment of the present invention includes an adhesive portion. This ensures both the strength of the nonwoven fabric and the suppression of fluff, and improves the ease of handling. Adhesion by adhesive fibers can be achieved by a portion of the adhesive fibers melting, softening, or changing to exhibit adhesive properties and fixing fibers that intersect with or contact with the adhesive fibers. Specifically, adhesion between fibers refers to adhesion between adhesive fibers and adhesion between adhesive fibers and cellulose fibers, and when other fibers are further included. Adhesive refers to the adhesion between fibers and other fibers. The adhesion may be by thermal adhesion in which heat is applied to melt or soften some of the adhesive fibers, or by irradiation with electron beams or the like or ultrasonic welding.

In the nonwoven fabric of this embodiment, the fibers are entangled with each other. That is, the nonwoven fabric according to the embodiment of the present invention includes intertwined portions. This ensures both the strength of the nonwoven fabric and the suppression of fluff, and improves the ease of handling. Entanglement of fibers can be achieved by subjecting the nonwoven fabric to a flow of material to cause the fibers to become entangled with each other. Specifically, the entanglement of fibers refers to the entanglement of adhesive fibers with adhesive fibers, the entanglement of adhesive fibers with cellulose fibers, the entanglement of cellulose fibers with cellulose fibers, and the entanglement of other fibers. If it further includes, it also refers to the entanglement of adhesive fibers and other fibers, the entanglement of cellulose fibers and other fibers, and the entanglement of other fibers and other fibers. The entanglement may be performed by a needle punch method or by a fluid stream, and the fluid stream may be a water stream, an air stream, a water vapor stream, or the like. In the nonwoven fabric of this embodiment, it is preferable to use water or steam flow to entangle the cellulose fibers.

The nonwoven fabric of this embodiment preferably has a basis weight of 10 to 150 g/m ² , more preferably 15 to 80 g/m ² , even more preferably 20 to 60 g/m ² Preferably, it is particularly preferable to have a basis weight of 25 to 50 g/m ² . It is preferable that the basis weight is not too small because both the softness of the texture of the nonwoven fabric and the suppression of fuzz are further improved. In addition, since the basis weight is not too small, entanglement progresses more moderately throughout the nonwoven fabric, and the adhesive intersection index A of the nonwoven fabric, the thickness reduction rate of the nonwoven fabric, the bending resistance per unit thickness of the nonwoven fabric, and the thickness of the nonwoven fabric will be described later. It is possible to more easily obtain a nonwoven fabric that exhibits values within a specific range with respect to the fiber bonding point angle in the middle when the nonwoven fabric is divided into three equal parts in the thickness direction. If the basis weight is not too large, the strength of the nonwoven fabric and the suppression of fuzz can be further improved.

The nonwoven fabric of this embodiment as a whole may have a fiber density of, for example, 0.0100 to 0.100 g/cm ³ and may have a fiber density of 0.0125 to 0.0600 g/cm ³ when dry. is preferred, and more preferably has a fiber density of 0.0180 to 0.0400 g/cm ³ . The fiber density of the entire nonwoven fabric can be determined from the basis weight and thickness (thickness measured by applying a load of 40 Pa).

In the nonwoven fabric of this embodiment, when a cross section cut along the thickness direction is observed, it is preferable that the fiber density on at least one surface (i.e., the front surface or the back surface) is higher than the fiber density inside. In this embodiment, it is more preferable that the fiber density on both the front and back surfaces is higher than the fiber density inside. It is more preferable that the fiber density on at least one surface is higher than the fiber density on the inside because both the softness of the texture of the nonwoven fabric and the suppression of fuzz can be further improved. Whether there is a difference between the fiber density inside the nonwoven fabric and the fiber density on the surface can be determined by observing a cross section of the nonwoven fabric cut along its thickness using an electron microscope (at a magnification of about 50x). . More specifically, when observed with an electron microscope, areas where fibers are more densely assembled are areas with higher fiber density, and areas where fibers are more sparsely aggregated are areas where fiber density is lower. It can be said that it is a field.

The level of fiber density can be confirmed, for example, by counting the number of cross sections of cut fibers per certain area using an electron microscope (magnification of about 50 times) in a cross section cut along the thickness direction of the nonwoven fabric. More specifically, when the cross section of the nonwoven fabric is divided into five equal parts along the thickness direction, the upper and lower fifths are referred to as the "surface of the nonwoven fabric" (the "upper surface" (upper surface) and the "upper surface", respectively). "Lower surface" (lower surface)), and when the cross section of the nonwoven fabric is divided into five equal parts along the thickness direction, the upper one-fifth part and the lower one-fifth part are excluded. If the ratio of the number of cross sections of fibers on the surface of the nonwoven fabric to the number of cross sections of the fibers inside the nonwoven fabric is 1.05 or more, when the part is defined as "inside the nonwoven fabric", the fiber density is higher on the surface of the nonwoven fabric than inside the nonwoven fabric. It can be considered as

In the nonwoven fabric of this embodiment, it is preferable that the adhesive fibers have adhesive peeling marks where the adhesive fibers have been removed. Adhesion peeling marks can be mainly formed by entangling treatment after adhesion treatment. In the adhesive peeling trace, the adhesive component (for example, the sheath component in the case of a core-sheath type composite fiber) is present thinly compared to the fiber surface of a normal adhesive fiber. It is preferable that adhesive peeling marks are included as appropriate, since these adhesive peeling marks can make the fibers easier to bend and improve the softness of the texture of the nonwoven fabric. Adhesive peeling marks can be confirmed by observing the surface or cross section of the nonwoven fabric using an electron microscope.

Although the nonwoven fabric of this embodiment may have another nonwoven fabric laminated on one side of the nonwoven fabric, it is preferable that at least one side is exposed. More preferably, both sides of the nonwoven fabric are exposed. The nonwoven fabric of this embodiment may have a single layer structure, but it may also have a laminated structure, for example, in which the blend ratio of cellulose fibers and adhesive fibers is varied in each layer. It is preferable that the nonwoven fabric of this embodiment has a single-layer structure because it can suppress fuzzing and have a soft texture on both sides of the nonwoven fabric. In addition, it is preferable that the nonwoven fabric has a single-layer structure because it is possible to suppress delamination between layers and a decrease in the strength of the nonwoven fabric due to a low degree of entanglement, and it is possible to suppress a decrease in the softness of the texture due to a high degree of entanglement. The nonwoven fabric of this embodiment is good in both the softness of the texture and the suppression of fluff, so it can be used in applications where the nonwoven fabric of this embodiment is exposed, such as top sheets and back sheets for absorbent articles, Liquid-impregnated skin dressings impregnated with liquids such as cosmetics (e.g., face masks, exfoliating sheets, decolletage sheets, etc.), base fabrics for various poultices including hot and cold compresses, and wipes for personal use. (For example, cleansing sheets, antiperspirant sheets, antibacterial sheets, etc.), disposable clothing, etc.

When the nonwoven fabric of this embodiment has a laminated structure, it is preferable because each layer can have different performance. For example, one layer can improve the texture of the nonwoven fabric, and the other layer can suppress fuzzing. Different layers can have varying degrees of hydrophilicity. Adhesive fibers may be included in at least two layers, and each layer may include adhesive fibers in which the melting point of the adhesive component is different.

The nonwoven fabric of the present invention preferably has an adhesive intersection index A of 1 to 60 pieces/mm ² as described in the following examples. The upper limit of the adhesive intersection index A is more preferably 55 pieces/mm ² , even more preferably 50 pieces/mm ² , and particularly preferably 45 pieces/mm ² . The lower limit of the adhesive intersection index A is more preferably 3 pieces/mm ² , and even more preferably 5 pieces/mm ² .
In the nonwoven fabric of the present invention, it is preferable that the adhesive intersection index A of the nonwoven fabric is within the above-mentioned range because the texture of the nonwoven fabric becomes more suitable.

The nonwoven fabric of the present invention preferably has a thickness reduction rate of 30 to 45%, more preferably 32 to 43%, and more preferably 34 to 41%, as explained in the following examples. is even more preferred.
It is preferable for the nonwoven fabric of the present invention to have a thickness reduction rate within the above-mentioned range because the texture of the nonwoven fabric becomes more suitable.

The nonwoven fabric of the present invention preferably has a bending resistance per unit thickness of the nonwoven fabric of 10 to 85 g/mm, more preferably 20 to 70 g/mm, as explained in the following examples. It is even more preferably from 30 to 60 g/mm, particularly preferably from 35 to 55 g/mm.
It is preferable for the nonwoven fabric of the present invention to have a bending resistance per unit thickness of the nonwoven fabric within the above-mentioned range because the texture of the nonwoven fabric becomes more suitable.

The nonwoven fabric of the present invention has a thickness ratio of, for example, 0.25 to 0.69, preferably 0.25 to 0.67, and preferably 0.35 to 0.67, as explained in the following examples. It is more preferably 0.65, and even more preferably 0.40 to 0.60.
In the nonwoven fabric of the present invention, when the thickness ratio of the nonwoven fabric is within the above-mentioned range, the softness of the texture of the nonwoven fabric becomes more suitable, and it is preferable. In addition, the thickness ratio of a nonwoven fabric is an index that indicates the proportion of fibers that are oriented in a direction parallel to the thickness direction of the nonwoven fabric (a direction more perpendicular to the surface of the nonwoven fabric). It is. The smaller the thickness ratio, the higher the proportion of fibers oriented in a direction parallel to the thickness direction of the nonwoven fabric.

In the nonwoven fabric of the present invention, when the nonwoven fabric described in the following examples is divided into three equal parts in the thickness direction, the angle of the fiber adhesion point in the middle of the nonwoven fabric is preferably 30 to 90 degrees, and 35 to 90 degrees. The temperature is more preferably 60 degrees, and even more preferably 40 to 50 degrees.
In the nonwoven fabric of the present invention, it is preferable that the angle of the fiber adhesion point in the middle of the nonwoven fabric is within the above-mentioned range because the softness of the texture of the nonwoven fabric becomes more suitable.

Regarding the breaking strength of the nonwoven fabric according to the embodiment of the present invention, the breaking strength in the MD direction is preferably 10 to 100 N, more preferably 15 to 70 N, and the breaking strength in the CD direction is preferably 10 to 100 N. It is preferably 1 to 25N, more preferably 2 to 12N. It is preferable that the nonwoven fabric according to the present invention has a strength within the above-mentioned range, since the handleability thereof is further improved.

The nonwoven fabric of the present invention preferably has a water retention rate of 800 to 2500%, more preferably 1000 to 2000%, and even more preferably 1100 to 1800%, as explained in the following examples. It is preferably 1250% to 1650%, particularly preferably 1250% to 1650%. It is preferable for the nonwoven fabric of the present invention to have a water retention rate within the above-mentioned range, since this provides suitable liquid impregnating or liquid retaining properties.
Furthermore, the nonwoven fabric of the present invention preferably has a water retention rate per unit thickness (water retention rate/thickness) of 1500 to 3000%, more preferably 1700 to 2800%, and more preferably 1900 to 3000%. Even more preferably it is 2600%. The thickness of the nonwoven fabric at this time is the thickness obtained by applying a load of 1.96 kPa, which will be described later. It is preferable for the nonwoven fabric of the present invention to have a water retention rate within the above-mentioned range, since this provides suitable liquid impregnating or liquid retaining properties.

The coefficient of variation CV of the dynamic frictional force of the nonwoven fabric according to the embodiment of the present invention, which will be explained in the following examples, is, for example, 0.081 or less, preferably 0.070 or less, and more preferably 0.060 or less. It is preferably 0.055 or less, and even more preferably 0.055 or less. A preferable lower limit of the coefficient of variation CV of the dynamic frictional force is 0.00. In the nonwoven fabric of the present invention, it is preferable that the coefficient of variation CV of the dynamic frictional force is within the above-mentioned range, since the surface of the nonwoven fabric becomes smoother.

The method for producing a nonwoven fabric of the present invention is a method for producing a nonwoven fabric containing cellulose fibers and adhesive fibers, which includes an adhesion step of adhering fibers to each other using the adhesive fibers, and interlacing the fibers after the adhesion step. and a confounding step.

(Method for manufacturing nonwoven fabric)
The nonwoven fabric of this embodiment is produced by mixing cellulose fibers, adhesive fibers, and other fibers if included to prepare a fibrous web, and bonding the fibers together with adhesive fibers to form bonded areas. It can be manufactured by intertwining the fibers with each other to provide intertwined points.
A fibrous web can be produced by a known method. The form of the fibrous web may be any form such as carded webs such as parallel webs, cross webs, semi-random webs, and random webs, air-lay webs, and wet papermaking webs. The form of the fibrous web is preferably a parallel web because the surface of the nonwoven fabric becomes smoother.

In the case of a laminated nonwoven fabric, for example, two fibrous webs are produced, and after the two fibrous webs are laminated to obtain one web, the fibers are bonded together with adhesive fibers to provide a bonding point, and the fibers are bonded together. It can be manufactured by intertwining and providing intertwined points. Note that the entire fibrous web may include cellulose fibers and adhesive fibers.

The fibrous web is subjected to a gluing treatment (or gluing step). The adhesive treatment may be, for example, heat treatment (thermal adhesive treatment). According to heat treatment, the component with the lowest melting point (thermal adhesive component) among the resin components that make up the adhesive fibers is melted or softened by heating during heat treatment, making it possible to bond the fibers that make up the fiber web to each other. . The heat treatment may be, for example, hot air processing in which hot air is blown, hot roll processing (e.g., hot embossing roll processing), or heat treatment using infrared rays, but hot air processing is preferred in order to improve the texture of the nonwoven fabric. The hot air processing treatment may be performed using a device that blows hot air at a predetermined temperature onto the fiber web, such as a hot air through-type heat treatment machine and a hot air blowing type heat treatment machine.

When the bonding treatment is hot air processing, it is preferable to spray hot air multiple times. Moreover, when blowing hot air multiple times, it is preferable that the temperature of the second hot air is higher than the temperature of the first hot air. The adhesiveness between cellulose fibers and adhesive fibers is not higher than the adhesiveness between adhesive fibers, so hot air may be sprayed multiple times to further increase the adhesiveness between cellulose fibers and adhesive fibers. It is valid.

When the adhesive treatment is hot air processing, the hot air speed is preferably 0.1 to 3.0 m/min, and 0.2 to 2 m/min, from the viewpoint of suppressing fluffing and improving the softness of the texture. The speed is more preferably .5 m/min, and even more preferably 0.3 to 2.0 m/min.

The temperature of the heat treatment may be a temperature at which the component with the lowest melting point (thermal adhesive component) among the resin components constituting the adhesive fiber softens or melts, and may be, for example, a temperature equal to or higher than the melting point of the component. For example, when the component with the lowest melting point among the resin components constituting the adhesive fiber is high-density polyethylene, hot air at a temperature of 130° C. to 150° C. may be blown when performing hot air processing. For example, if the component with the lowest melting point among the resin components constituting the adhesive fiber is an ethylene-acrylic acid copolymer, hot air at a temperature of 90°C to 140°C may be blown during hot air processing. In particular, hot air at a temperature of 95 to 130° C. may be blown, more particularly hot air at a temperature of 100 to 120° C. may be blown. In addition, the temperature of the heat treatment is preferably 0°C or more and 5°C or less higher than the melting point or softening point of the thermal adhesive component, and 1°C or more and 4°C or more, from the viewpoint of suppressing fuzzing and improving the softness of the texture. It is more preferable to set the temperature higher than 0.degree. C., and even more preferably to set the temperature higher than 2.degree. C. or higher and 3.degree. C. or lower.

The adhesion treatment may be performed by irradiation with an electron beam or the like, or by ultrasonic welding. These adhesive treatments also allow the fibers to be adhered to each other using the resin component that constitutes the adhesive fibers.

For example, when the fibrous web that has been subjected to the adhesion treatment and before the entanglement treatment has a breaking strength of 1.0 N/5 cm or more in the MD direction, the adhesion is sufficient and fuzz is suppressed. This is preferable because it makes it easier to obtain the nonwoven fabric of the present disclosure that has good properties. The breaking strength is more preferably 2.0 N/5 cm or more in the MD direction, and even more preferably 3.0 N/5 cm or more. In addition, if the fibrous web that has been subjected to the adhesive treatment and before the entangling treatment has a bending resistance of 100 g or less obtained by the method described in the examples, the texture will be soft. This is preferable because it becomes easier to obtain the nonwoven fabric of the present disclosure that has good properties. The bending resistance is more preferably 80 g or less, and even more preferably 60 g or less.

The fibrous web is further subjected to an entangling treatment (or entangling step). Examples of the entanglement treatment include water flow entanglement treatment and water vapor flow entanglement treatment, and it is preferable to include either one of these. It is preferable that the entangling step includes hydroentangling treatment. According to these intertwining treatments, intertwining with cellulose fibers can be easily performed and a nonwoven fabric having desired physical properties can be obtained.

The manufacturing method of the embodiment of the present invention preferably includes a cooling treatment (or cooling step) between the adhesion treatment (or bonding step) and the entangling treatment (or entangling step). That is, the fibrous web is preferably subjected to a cooling treatment (or a cooling step) after being subjected to the adhesion treatment and before being subjected to the entangling treatment. Examples of the cooling step include air cooling or water cooling. If the fibrous web is not sufficiently cooled after being subjected to the adhesive treatment, the adhesive component of the adhesive fibers may be in a softened state. If the fibrous web is subjected to the entanglement treatment in this state, the bonded portions may easily peel off, and the fluffing of the nonwoven fabric may be insufficiently suppressed.

The hydroentangling treatment can be carried out by placing the fibrous web on a support and spraying a columnar water stream onto it. If the surface of the nonwoven fabric is flat and has no irregularities, the support should not have pores each having an area of 0.2 ^mm2 or more, and should not have protrusions or patterns formed thereon. It is best to use a support that is not For example, the support may be a plain weave support of 80 mesh or more and 100 mesh or less.

In the hydroentangling process, for example, a water stream with a water pressure of 1 MPa or more and 15 MPa or less is applied to the fiber web from a nozzle in which orifices with a hole diameter of 0.05 mm or more and 0.5 mm or less are provided at intervals of 0.3 mm or more and 1.5 mm or less. This can be carried out by spraying 1 to 5 times on each of the front and back surfaces of. The water pressure is preferably 1 MPa or more and 10 MPa or less, more preferably 1 MPa or more and 7 MPa or less.

The support used during the hydroentangling treatment may be a plate-shaped or roll-shaped support, and is preferably a roll-shaped support. When the support is in the form of a roll, the fibrous web is curved, resulting in a lower fiber density in the thickness direction of the fibrous web (or generally in the outward direction of a curved web). When the columnar water stream is injected from the outside, the entanglement due to the columnar water stream progresses relatively easily. In the nonwoven fabric of this embodiment, it is preferable that the fibrous web is subjected to adhesion treatment and then entangling treatment, and when the fibrous web is subjected to interlacing treatment after adhesion treatment, the fibrous web includes bonded portions. Since entanglement is relatively difficult to proceed, it is preferable to perform the hydroentanglement treatment in a state where entanglement is more likely to proceed.

When the adhesion treatment is hot air processing, the hydroentangling treatment preferably includes spraying a columnar water stream first from the side to which the hot air was blown in the hot air processing, and further includes spraying the columnar water stream from the opposite side. It is preferable to include. In hot air processing, the fiber density tends to be lower on the side to which hot air is blown than on the opposite side (generally the side in contact with the support), and entanglement by columnar water flows is relatively easy to proceed. The strength of the nonwoven fabric and the extent to which fluffing is suppressed by hydroentangling treatment largely depends on the degree of entanglement in the initial entanglement treatment. Preferably, this is carried out by spraying a water stream.

When the entangling treatment is a hydroentangling treatment, the fibrous web is preferably subjected to a drying treatment (drying step) after the entangling treatment. The drying process can be performed by hot air processing, etc., in which hot air is blown. The temperature of the drying treatment is preferably lower than the temperature at which the adhesive component (thermal adhesive component) of the adhesive fiber softens or melts. The temperature of the drying treatment is preferably 10°C or more lower than the melting point or softening point of the thermal adhesive component, more preferably 15°C or more lower, and even more preferably 20°C or lower. . If the adhesive component is not softened or melted again after the entanglement treatment, the bulk of the nonwoven fabric will be difficult to lose, and the texture of the nonwoven fabric will be difficult to harden.

When two or more adhesive fibers are included and the melting point or softening point of the thermal adhesive component of each adhesive fiber is different, the melting point or softening point of the thermal adhesive component with a higher melting point or softening point is T ₁ (°C), melting point or The melting point or softening point of the thermal adhesive component with a lower softening point is T ₂ (°C), and the temperature of the drying treatment is T (°C), and T ₁ , T ₂ , and T satisfy the relationship T ₂ ≦T < T ₁ It is preferable. In particular, T≦T ₁ +10, more particularly T≦T ₁ +15, and still more particularly T≦T ₁ +20. When the nonwoven fabric contains two or more adhesive fibers and has a laminated structure, and the melting point or softening point of the thermal adhesive component of the adhesive fibers differs for each layer in at least two layers, the temperature of the drying treatment is set to T ₂ ≦T<T. ₁ , the texture of the nonwoven fabric is improved in the layer containing adhesive fibers with a melting point or softening point of T ₁ , and the feel of the nonwoven fabric is improved in the layer containing adhesive fibers with a melting point or softening point of T ₂ . can be effectively suppressed.

It is preferable that the fibrous web is subjected to an adhesive treatment and an interlacing treatment in this order. It is preferable that the thermal adhesion treatment and the entangling treatment are performed in this order because the intertwining of the fibers proceeds appropriately and a more suitable soft texture can be obtained. It is preferable that the entangling treatment is applied continuously after the adhesion treatment. For example, when a fibrous web that has been subjected to an adhesive treatment is once wound into a roll and then subjected to an entangling treatment, the softness of the texture tends to be reduced due to the winding pressure, and the friction between the fibrous webs during unwinding may cause Fuzzing may occur more easily.

In the thermal bonding treatment, it is preferable to heat so that the low melting point component of the adhesive fiber melts, and it is more preferable to heat so that only the low melting point component melts. By appropriately melting the low melting point component, a more appropriate size and a more appropriate number of bonding points can be formed, and the softness of the texture of the nonwoven fabric can be further improved.
By adjusting the heat treatment temperature, it is also possible to change the degree of thermal adhesion (for example, the size and number of bonded parts) due to the low melting point component. By adjusting the degree of thermal adhesion, the strength of the nonwoven fabric, the suppression of fuzz, the softness of the texture, etc. can be further improved, and the degree of entanglement can also be adjusted.

The nonwoven fabric of the embodiment of the present invention can be used, for example, in absorbent articles such as disposable diapers, sanitary napkins, incontinence pads, and panty liners, wipes for people or objects, and skin coverings such as face masks impregnated with cosmetics. , gauze, disposable clothing, etc. Furthermore, it has an excellent overall balance of properties and is suitable for applications that come in direct contact with human skin, such as top sheets and back sheets for absorbent articles, and liquid-impregnated skin dressings impregnated with liquids such as cosmetics (for example, face Masks, keratin care sheets, decollete sheets, etc.), base fabrics for various poultices including hot and cold compresses, and wipes for personal use (e.g. cleansing sheets, antiperspirant sheets, antibacterial sheets, etc.), etc. can be used.

The present invention will be explained below using Examples and Comparative Examples, but these examples are for illustrating the present invention and are not intended to limit the present invention in any way.

The fibers used to produce the nonwoven fabrics of Examples and Comparative Examples are shown below.
Fiber 1 (cellulose fiber): Solvent spun cellulose fiber (Lyocell (trade name) manufactured by Lenzing) with a fineness of 1.7 dtex and a fiber length of 40 mm. The settling speed is 4 seconds.
Fiber 2 (adhesive fiber): The core is polyethylene terephthalate and the sheath is high-density polyethylene (melting point: about 133°C), the fineness is 2.6 dtex, the fiber length is 51 mm, and the eccentricity has three-dimensional crimp with an eccentricity rate of 25%. Core-sheath type composite fiber (NBF(SH)V (trade name) manufactured by Daiwabo Polytec Co., Ltd.).
Fiber 3 (adhesive fiber): core is polypropylene (melting point 160°C), sheath is ethylene-acrylic acid copolymer (acrylic acid 8.5-10% by mass) (melting point 95°C), fineness 3. A concentric core-sheath type composite fiber (NBF(A) (trade name) manufactured by Daiwabo Polytech Co., Ltd.) having a mechanical crimp of 3 dtex and a fiber length of 51 mm.
Fiber 4 (cellulose fiber): Cotton (MSD (trade name) manufactured by Marusan Sangyo Co., Ltd.) with a fineness of 1.0 to 5.0 dtex (average 2.5 dtex) and a fiber length of 10 to 60 mm. The settling speed is 10 seconds.
Fiber 5 (cellulose fiber): Water-repellent rayon with a fineness of 1.7 dtex and a fiber length of 40 mm. The settling speed does not sink for more than 5 minutes.

<Production of nonwoven fabrics of Examples 11 to 13>
A fibrous web was produced using a parallel card machine using Fiber 1 and Fiber 2 at a mixing ratio of 2:8 (mass ratio). The basis weight of this fibrous web was approximately 35 g/m ² .
This fibrous web was heated at 135° C. for about 5 seconds using a hot air through-type heat treatment machine. An air-through nonwoven fabric was obtained in which the fibers were thermally bonded (adhered) to each other using the sheath component of Fiber 2. After thermal bonding (adhesion treatment), the air-through nonwoven fabric was subjected to a cooling treatment by air cooling at a room temperature of 20°C.
The air-through nonwoven fabric described above was placed on a plain-woven PET net having a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90 meshes. While the air-through nonwoven fabric was traveling at a speed of 4 m/min, a columnar water stream with a water pressure of 2.0 MPa was injected onto the surface of the air-through nonwoven fabric using a water supply device. The nozzle of the water supply device was provided with orifices having a hole diameter of 0.12 mm at intervals of 0.6 mm. The distance between the surface of the air-through nonwoven fabric and the orifice was 15 mm. Thereafter, a columnar water stream was similarly sprayed onto the back surface of the air-through nonwoven fabric using a water supply device. The fibers were hydroentangled (entangled treatment) as described above. After the entanglement treatment, a drying treatment was performed using a hot air through-type heat treatment machine set at 80° C. to obtain a nonwoven fabric (single layer) of Example 11.
A nonwoven fabric of Example 12 was obtained using the same method as Example 11, except that a columnar water stream with a water pressure of 3.0 MPa was sprayed on the front and back surfaces (both sides).
A nonwoven fabric of Example 13 was obtained in the same manner as in Example 11, except that a columnar water stream with a water pressure of 3.5 MPa was sprayed onto the front and back surfaces, respectively.

<Production of nonwoven fabrics of Examples 21 to 23>
A nonwoven fabric of Example 21 was obtained in the same manner as in Example 11 except that Fiber 1 and Fiber 2 were used at a mixing ratio of 4:6.
A nonwoven fabric of Example 22 was obtained in the same manner as in Example 21, except that a columnar water stream with a water pressure of 3.0 MPa was sprayed onto the front and back surfaces, respectively.
A nonwoven fabric of Example 23 was obtained in the same manner as in Example 21, except that a columnar water stream with a water pressure of 3.5 MPa was sprayed onto the front and back surfaces, respectively.

<Production of nonwoven fabrics of Examples 31 to 33>
Nonwoven fabrics of Examples 31 to 33 were obtained using the same method as in Examples 21 to 23, except that Fiber 1 and Fiber 2 were used at a blend ratio of 6:4.
<Production of nonwoven fabrics of Examples 41 to 43>
Nonwoven fabrics of Examples 41 to 43 were obtained in the same manner as in Examples 21 to 23, except that Fiber 1 and Fiber 2 were used at a mixing ratio of 8:2.

<Manufacture of nonwoven fabric of Comparative Example 50>
A nonwoven fabric of Comparative Example 50 was obtained using the same method as Example 11, except that Fiber 1 and Fiber 2 were used at a mixing ratio of 6:4, and the treatment using a water stream and the drying treatment were not performed.
<Manufacture of nonwoven fabrics of Comparative Examples 61 and 62>
A nonwoven fabric of Comparative Example 61 was obtained in the same manner as in Example 11, except that Fiber 1 and Fiber 2 were used at a blend ratio of 6:4 and heat treatment (adhesion treatment) and cooling treatment were not performed.
A nonwoven fabric of Comparative Example 62 was obtained using the same method as Comparative Example 61, except that a water stream with a water pressure of 3.0 MPa was used on each of the front and back surfaces.

<Manufacture of nonwoven fabrics of Comparative Examples 71 and 72>
A fibrous web was produced using Fiber 1 and Fiber 2 at a blend ratio of 6:4.
The same method as in Example 11 was used, except that a columnar water stream with a water pressure of 2.0 MPa was sprayed on the front and back surfaces of the fibrous web, and then heat treated at 135 ° C. for about 5 seconds using a hot air through-type heat treatment machine. Thus, a nonwoven fabric of Comparative Example 71 was obtained.
A nonwoven fabric of Comparative Example 72 was obtained using the same method as Comparative Example 71, except that a columnar water stream with a water pressure of 3.0 MPa was sprayed onto the front and back surfaces, respectively.

<Manufacture of nonwoven fabric of Example 81>
Fiber 1 and Fiber 2 were prepared at a ratio of 6:4 (mass ratio), and only the respective fibers were used to produce respective fibrous webs using a parallel card machine. The total basis weight of these two fibrous webs was approximately 35 g/m ² .
The fibrous web obtained by stacking these two fibrous webs was heated at 135° C. for about 5 seconds using a hot air penetration type heat treatment machine. An air-through nonwoven fabric was obtained in which the fibers were thermally bonded (adhered) to each other using the sheath component of Fiber 2. Note that the hot air was applied from the side of the fiber web containing fiber 1. After thermal bonding (adhesion treatment), the air-through nonwoven fabric was cooled by air cooling at a room temperature of 20°C.
The air-through nonwoven fabric described above was placed on a plain-woven PET net having a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90 meshes. While the air-through nonwoven fabric was traveling at a speed of 4 m/min, a columnar water stream with a water pressure of 3.0 MPa was injected onto the surface of the air-through nonwoven fabric (the side of the layer containing fibers 1) using a water supply device. The nozzle of the water supply device was provided with orifices having a hole diameter of 0.12 mm at intervals of 0.6 mm. The distance between the surface of the air-through nonwoven fabric and the orifice was 15 mm. Thereafter, a columnar water stream was similarly sprayed onto the back surface of the air-through nonwoven fabric using a water supply device. The fibers were hydroentangled (entangled treatment) as described above. After the entanglement treatment, a drying treatment was performed using a hot air through-type heat treatment machine set at 80° C. to obtain a nonwoven fabric (laminated) of Example 81.

<Manufacture of nonwoven fabric of Example 82>
A fibrous web A was produced using a parallel card machine using Fiber 1 and Fiber 2 at a mixing ratio of 7:3 (mass ratio). The basis weight of this fibrous web A was approximately 17.5 g/m ² . Next, a fibrous web B was produced using a parallel card machine using Fiber 1 and Fiber 2 at a mixing ratio of 5:5 (mass ratio). The basis weight of this fibrous web B was approximately 17.5 g/m ² .
The fibrous web obtained by stacking these two fibrous webs was heated at 135° C. for about 5 seconds using a hot air penetration type heat treatment machine. An air-through nonwoven fabric was obtained in which the fibers were thermally bonded (adhered) to each other using the sheath component of Fiber 2. Note that the hot air was applied from the fiber web A side. After thermal bonding (adhesion treatment), the air-through nonwoven fabric was cooled by air cooling at a room temperature of 20°C.
The air-through nonwoven fabric described above was placed on a plain-woven PET net having a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90 meshes. While the air-through nonwoven fabric was traveling at a speed of 4 m/min, a columnar water stream with a water pressure of 2.0 MPa was injected onto the surface of the air-through nonwoven fabric (fiber web A side) using a water supply device. The nozzle of the water supply device was provided with orifices having a hole diameter of 0.12 mm at intervals of 0.6 mm. The distance between the surface of the air-through nonwoven fabric and the orifice was 15 mm. Thereafter, a columnar water stream was similarly sprayed onto the back surface of the air-through nonwoven fabric using a water supply device. The fibers were hydroentangled (entangled treatment) as described above. After the entanglement treatment, a drying treatment was performed using a hot air through-type heat treatment machine set at 80° C. to obtain a nonwoven fabric (laminate) of Example 82. In the entire nonwoven fabric of Example 82, the blend ratio of fiber 1 and fiber 2 was 6:4 (mass ratio).

<Manufacture of nonwoven fabric of Example 83>
A nonwoven fabric of Example 83 was obtained using the same method as Example 82, except that the hot air was applied from the fibrous web B side and the columnar water stream was sprayed from the fibrous web B side first.

<Production of nonwoven fabrics of Examples 84 to 86>
The same method as in Example 31 was used, except that instead of Fiber 1 and Fiber 2, Fiber 1 and Fiber 3, Fiber 4 and Fiber 2, and Fiber 5 and Fiber 2 were used at a mixing ratio of 6:4. , nonwoven fabrics (single layer) of Examples 84 to 86 were obtained.

Evaluation of the nonwoven fabric was performed as follows.
<Structure of nonwoven fabric>
The structure of the nonwoven fabric can be determined by cutting the nonwoven fabric in the longitudinal direction (more specifically, in the direction parallel to the traveling direction of the belt conveyor of the heat treatment machine and water treatment machine that treated the nonwoven fabric), and examining the cut surface with a scanning electron microscope (SEM). , magnification: 60 times). The results are shown in Tables 1 and 2.
A SEM image of the nonwoven fabric of Example 31 is shown in FIG. It can be seen that the nonwoven fabric of Example 31 has a dense/loose/dense structure in which the number of fibers inside the nonwoven fabric is smaller than the number of fibers on the front and back surfaces.
A SEM image (magnification: 25 times) of the nonwoven fabric of Comparative Example 50 is shown in FIG. It can be seen that the nonwoven fabric of Comparative Example 50 has substantially no difference in the number of fibers inside the nonwoven fabric and the number of fibers on the front and back surfaces, and does not have a dense/loose/dense structure.

<Glue point angle measurement>
Regarding the taken SEM images, when the nonwoven fabric was divided into three equal parts in the thickness direction, the apparent angles formed by the two fibers forming the bonding points were examined near the front and back surfaces and near the middle (inside) of the nonwoven fabric. The apparent angles formed at at least four locations were examined and the average value was determined. The results are listed in Tables 1 and 2. In addition, for the Examples and Comparative Examples in which processing was performed using a hot air penetration type heat treatment machine, the side to which hot air was applied was defined as the front surface, and the opposite surface was defined as the back surface.

式中、
α_ｉは、ｉ番目の非接着性繊維の混率（質量％）を表し、
ｘ_ｉは、ｉ番目の非接着性繊維の繊度（dtex）を表し、
β_ｊは、ｊ番目の接着性繊維の混率（質量％）を表し、
ｙ_ｊは、ｊ番目の接着性繊維の繊度（dtex）を表す。
接着交点数Ｉと接着交点割合Ｐとから、接着交点指数Ａ（単位：個／ｍｍ^２）を下記の式に従って求めた。
接着交点指数Ａ＝Ｉ／（Ｐ^２） <Adhesive intersection index A>
The front and back surfaces of the nonwoven fabric were observed using a scanning electron microscope (SEM, acceleration voltage: 10.0 kV, magnification: 100 times). The number of bonded intersections of fibers per area was counted for the SEM images taken. The number of fiber adhesive intersections was counted for a total of six SEM images, three each for the front and back sides of the nonwoven fabric, and the average value was taken as the number I (unit: pieces/mm ² ) of fiber adhesive intersections.
From the fineness (dtex) of non-adhesive fibers (fiber 1) and adhesive fibers (fiber 2) constituting the non-woven fabrics of Examples and Comparative Examples and the blending ratio (mass%) in the non-woven fabric, the adhesive intersection ratio P (0≦P ≦1) was determined according to the following formula.

During the ceremony,
α _i represents the mixing ratio (mass%) of the i-th non-adhesive fiber,
x _i represents the fineness (dtex) of the i-th non-adhesive fiber,
β _j represents the mixing ratio (mass%) of the j-th adhesive fiber,
y _j represents the fineness (dtex) of the j-th adhesive fiber.
From the number I of adhesive intersections and the ratio P of adhesive intersections, the adhesive intersection index A (unit: pieces/mm ² ) was determined according to the following formula.
Adhesive intersection index A=I/(P ² )

In the case of a two-layer structure, the adhesion intersection ratio P on the front or back side is calculated depending on the cotton blend state on the front or back side. The calculation of the adhesive intersection index A is still the average value of the three front and three back surfaces. In the case of Example 81, the adhesive intersection index A of the plane of fiber 1 is 0 (I=0). The adhesive intersection index A of the plane of fiber 2 is 28 (P=1). On average, the adhesive intersection index A of Example 81 is 14.

<Thickness and density of nonwoven fabric>
Using a thickness measuring machine (THICKNESS GAUGE model CR-60A (trade name) manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), the thickness of the nonwoven fabric was measured with a load of 1.96 kPa applied to the nonwoven fabric.
Alternatively, using a CCD laser displacement meter (amplifier unit model: LK-2100, sensor head model: LK-080, manufactured by Keyence Corporation), the thickness of the nonwoven fabric was measured with a load of 40 Pa applied to the nonwoven fabric. The results are shown in Tables 1 and 2.
The density of the nonwoven fabric was calculated based on the basis weight of the nonwoven fabric and the thickness of the nonwoven fabric obtained by applying a load of 40 Pa.
Also, the ratio of the thickness obtained by applying a load of 1.96 kPa to the thickness obtained by applying a load of 40 Pa (thickness obtained by applying a load of 1.96 kPa/thickness obtained by applying a load of 40 Pa) ) is defined as the "thickness ratio".

<Thickness reduction rate of nonwoven fabric>
Regarding the nonwoven fabric sample piece, the thickness (initial thickness) of the nonwoven fabric under a load of 40 Pa was measured in the same manner as described above. Next, after leaving the same sample piece under a load of 1.63 kPa for 3 days, the same method was repeated except for the load of 1.63 kPa, and the thickness of the nonwoven fabric was then applied with a load of 40 Pa. The thickness (final thickness) was measured. The thickness reduction rate (%) was determined according to the following formula.
Thickness reduction rate (%) = [(Initial thickness - Final thickness) / Initial thickness] x 100

<Bending resistance>
The bending resistance of the nonwoven fabric was measured according to JIS L 1096:2010 8.21.5 E method (handle-o-meter method). Specifically, the measurement was performed using the following procedure.
A test piece measuring 20 cm in length and 20 cm in width was placed on a sample stand so that the measurement direction of the test piece was perpendicular to the slot (gap width 10 mm).
Next, the blade of the penetrator, which was adjusted to fall down to 8 mm from the surface of the sample stage, was lowered to press the test piece. When pressed, the resistance value against pressing was read at a position 6.7 cm (1/3 of the width of the test piece) from either side and at different locations on the front and back in both the vertical and horizontal directions. As the resistance value, the highest value indicated by the microammeter was read. The total value of the highest values on the four sides was determined, and the average value of the total values three times was calculated to determine the bending resistance (g) of the sample.
In addition, the value obtained by dividing the above bending resistance by the thickness (value obtained by applying a load of 1.96 kPa) is calculated as the bending resistance per unit thickness (bending resistance/thickness (g/mm)). It was defined as

<Strong elongation>
The strength and elongation was measured according to JIS L 1096:2010 8.14.1 Method A (strip method). A tensile test was conducted using a constant speed tension type tensile testing machine under the conditions that the sample piece (nonwoven fabric) had a width of 5 cm, a grip interval of 10 cm, and a tensile speed of 30±2 cm/min. The load value at cutting (breaking strength), elongation at break, stress at 10% elongation, stress at 20% elongation, and stress at 30% elongation were measured. The tensile test was conducted with the longitudinal direction (MD direction) and the lateral direction (CD direction) of the nonwoven fabric as the tensile directions. The evaluation results were all shown as the average of the values measured for three samples.

<Maximum friction force and kinetic friction force>
The maximum frictional force and the dynamic frictional force were measured using a static/dynamic friction measuring device (Tribomaster TL201Ts, manufactured by Trinity Lab Co., Ltd.). A 5 cm x 10 cm nonwoven fabric was prepared as a sample piece. In addition, sample pieces were prepared in which the long side of the nonwoven fabric was in the MD direction and the other in which the long side was in the CD direction. A tactile contact (manufactured by Trinity Lab Co., Ltd.) was used as the contact terminal of the measuring device. The sample piece was fixed to a measuring machine, and the contact terminal was moved twice against the surface of the sample piece at a load of 30 g, a speed of 10 mm/sec, and a distance of 30 mm for evaluation. In addition, for Examples and Comparative Examples in which processing was performed using a hot air penetration type heat treatment machine, measurements were made by bringing the contact terminal into contact with the surface opposite to the surface to which the hot air was applied. The values of the second round trip were read, and the average value of the previous value and the return value was taken as the maximum frictional force (gf) and dynamic frictional force (gf) of one sample piece. Measurement was performed three times on a test piece with the long side in the MD direction and three times on a test piece with the long side in the CD direction, and the average value of the total six measurements was calculated as the maximum friction force of each example and comparative example. Fs (gf) and dynamic friction force Fk (gf).
Further, the coefficient of variation CV of the dynamic friction force was determined from the standard deviation σ (gf) of the dynamic friction force obtained during the measurement and the average value Fk of the dynamic friction force described above, according to the following formula.
Coefficient of variation of dynamic friction force CV=σ/Fk

<Water retention rate>
The nonwoven fabric was cut into MD direction x CD direction = 100 mm x 100 mm, and the mass of the nonwoven fabric was measured. After that, the nonwoven fabric was placed in distilled water for testing (two drops of dish detergent (Joy Refreshing Orange Scent (contains 33% surfactant), manufactured by Procter & Gamble) added to 1 liter of distilled water). Soaked for 2 minutes. The three corners of the nonwoven fabric impregnated with distilled water for testing were held between clothespins and hung. After 10 minutes, the mass of the nonwoven fabric (containing water) was measured. The water retention rate of the nonwoven fabric was calculated according to the following formula.
Water retention rate (%) = [(M2-M1)/M1] x 100
M1: Mass (g) of nonwoven fabric before soaking in distilled water for testing
M2: Mass (g) of the nonwoven fabric after hanging the nonwoven fabric soaked in distilled water for testing for 10 minutes

<Fuzz evaluation>
The surface of the disk (diameter 70 mm, 350 g) was covered with 0.5 mm thick urethane foam. The disk was attached to the rotating shaft at a position where the center of the disk was shifted by 20 mm from the rotating shaft. A nonwoven fabric with urethane foam underneath was fixed on a table. The above disc was placed on a nonwoven fabric, and the rotating shaft was rotated to move the disc around the nonwoven fabric. The rotation was performed twice clockwise and twice counterclockwise. The circumferential speed at this time was approximately 3 seconds per circumferential movement. After the rotation, the fluff condition of the nonwoven fabric was evaluated using the following criteria. 3 to 5 are considered to have suppressed fuzz.
5: Very good (no fuzz)
4: Good (very little fuzz)
3: Normal (fuzz is not noticeable)
2: Bad (fuzz is noticeable)
1: Very bad (a lot of fluff)

<Fuzz evaluation 2>
Evaluation was performed by an abrasion test using a Martindale Abrasion and Pilling Tester No. 1309, manufactured by James Heal.
Two samples (one each with a diameter of 140 mm and one with a diameter of 38 mm) were prepared for the nonwoven fabrics of Examples and Comparative Examples. Felt with a diameter of 140 mm was placed on an abrading table, a sample with a diameter of 140 mm was stacked on SM25 abrasive cloth, and the sample was fixed with a clamp ring. Next, a sample with a diameter of 38 mm and a polyurethane with a diameter of 38 mm were placed in a sample holder. The measurement conditions were that the sample holder was placed on a table (Abrading Tables) without installing a loading weight on the sample holder. A friction test was conducted by setting the number of frictions to 8 rotations and the motion to 60.5 mm Lissajous. For Examples and Comparative Examples processed using a hot air penetration type heat treatment machine, a friction test was conducted so that the surfaces opposite to the side to which the hot air was applied were in contact with each other. After the measurement, observe the nonwoven fabric on the sample holder side and judge the fluff condition using the following two criteria: the condition when the nonwoven fabric after measurement is viewed from directly above (surface condition), and the condition when the nonwoven fabric is viewed from the side after measurement. Evaluation was made based on the total condition (fuzziness) (out of 10 points). A total of 6 points or more is considered to indicate that fluff is suppressed. The evaluation test was conducted three times for each Example or Comparative Example, and the average value of the three evaluations was used as the fuzz evaluation for each Example or Comparative Example.
Surface condition 5: Very good (no surface disturbance)
4: Good (very little surface disturbance)
3: Normal (there is little disturbance on the surface and it is not noticeable)
2: Bad (there is a noticeable amount of surface disturbance)
1: Very bad (holes on the surface)
Fluffiness 5: Very good (no fluffing)
4: Good (very little fluff)
3: Normal (fuzz is not noticeable)
2: Bad (fuzziness is noticeable)
1: Very bad (a lot of fluff)
Regarding fluff, there are two evaluation methods: <Fuzz Evaluation> and <Fuzz Evaluation 2>, but a score of 3 or higher for <Fuzz Evaluation> is considered a pass, and a total of 6 or higher for <Fuzz Evaluation 2>. If so, you will pass. Further, if either <Fuzz Evaluation> or <Fuzz Evaluation 2> is passed, the fluff is considered to be passed. It is more preferable for fluff to pass both <Fuzz Evaluation> and <Fuzz Evaluation 2>.

The nonwoven fabrics of Examples 11 to 43 and 81 to 86 all contain cellulose fibers and adhesive fibers, include bonding locations between the adhesive fibers and the cellulose fibers and/or the adhesive fibers, and include the adhesive fibers and the cellulose fibers and/or the adhesive fibers. Includes intertwining locations of cellulosic fibers and cellulosic fibers and/or adhesive fibers. Furthermore, the nonwoven fabrics of Examples 11 to 43 and 81 to 86 all have (i) an adhesive intersection index A of the nonwoven fabric of 1 to 60 pieces/mm ² , and/or (ii) a thickness of the nonwoven fabric. It is characterized by a reduction rate of 30 to 45%.

The nonwoven fabrics of Examples 11 to 43 and 81 to 86 contain both bonded areas and intertwined areas, and therefore suppress fluffing well.
Further, the nonwoven fabrics of Examples 11 to 43 and 81 to 86 have a soft and good texture because either (i) or (ii) above exhibits the above specific value.
Therefore, the nonwoven fabrics of Examples 11 to 43 and 81 to 86 exhibit excellent properties of suppressing fuzz and having good texture.

On the other hand, the nonwoven fabrics of Comparative Examples 50 to 72 do not have good fluff control or feel. For example, Comparative Examples 50 to 62 have only one of the bonded portion and the entangled portion. Therefore, the suppression of fuzz is insufficient. Comparative Examples 71 and 72 have both bonded areas and intertwined areas, so they suppress fluff well, but either (i) or (ii) does not exhibit the above-mentioned specific value, so the texture is poor. is hard and insufficient.

When confirming the bending resistance per unit thickness of the nonwoven fabric, the values of the nonwoven fabrics of Comparative Example 71 and Comparative Example 72 are larger than those of the nonwoven fabrics of Examples 11 to 43 and 81 to 86, and the nonwoven fabric of Examples is higher. The texture is soft and good.

Concerning the thickness ratio of the nonwoven fabric, when checking Examples 31 to 33 and Comparative Examples 71 to 72, which have the same blending ratio, the value of the nonwoven fabric of the comparative example is larger than that of the nonwoven fabric of the example, and the nonwoven fabric of the example is better. The texture is soft and good. Furthermore, when comparing Examples 31 to 33 and Comparative Example 50, which have the same blending ratio, the value of the nonwoven fabric of Comparative Example is smaller than that of the nonwoven fabric of Example, and the nonwoven fabric of Example is more resistant to sagging.

Regarding the angle of the fiber adhesion point in the middle when the nonwoven fabric is divided into three equal parts in the thickness direction, when comparing Example 31 with the same blend ratio, Comparative Example 50, and Comparative Example 71, it is found that the nonwoven fabric of Example 31 has a lower angle than the nonwoven fabric of Example 31. The nonwoven fabric of Example 71 has a smaller value, and the nonwoven fabric of Examples has a softer and better texture. Moreover, the value of the nonwoven fabric of Comparative Example 50 is larger than that of the nonwoven fabric of Example 31, and the nonwoven fabric of Example is more resistant to fading. Further, in Example 84 in which mechanically crimped fibers were used as the adhesive fibers, the angle value was small, so it is considered that the adhesive fibers having three-dimensional crimps can have a softer texture.

Concerning the coefficient of variation of the dynamic friction force of the nonwoven fabric, when comparing Examples 11, 21, 31, and 41 with the same water pressure and Comparative Example 71, it was found that the nonwoven fabric of the Example had a smaller value than the nonwoven fabric of the Comparative Example. Non-woven fabric has a smoother surface. Similarly, in Examples 12, 22, 32, and 42, and Comparative Example 72, which had the same water pressure, the surface of the nonwoven fabric of the Example was smoother. It is surmised that by performing the adhesion process before the entanglement process, the fibers can be entangled to an appropriate degree, and the surface of the nonwoven fabric can be made smooth. In particular, in the Examples and Comparative Examples, the fiber webs were manufactured using a parallel card machine, so the fibers were relatively oriented in the MD direction. By performing the adhesion process before the interlacing process, the fiber orientation was relatively maintained, and the nonwoven fabric It is assumed that the surface has become smoother.

The nonwoven fabric of Example 31 was cut in the transverse direction (more specifically, perpendicular to the traveling direction of the belt conveyor of the heat treatment machine and water treatment machine that treated the nonwoven fabric), and the cut surface was examined using a scanning electron microscope. (SEM, magnification: 100 times). Figure 3 is an enlarged cut portion of the nonwoven fabric near the middle (inside) when the nonwoven fabric is divided into three equal parts in the thickness direction. It can be seen that removed adhesive peeling marks are formed on the adhesive fiber.
Regarding the nonwoven fabric of Example 31, the front and back sides of the nonwoven fabric were observed using a scanning electron microscope (SEM, magnification: 100x). FIG. 4 shows an observation of the surface of the nonwoven fabric, and it can be seen that in the nonwoven fabric of Example 31, on the surface of the nonwoven fabric, adhesive peeling traces were formed on the adhesive fibers where the adhesive fibers had been removed. Recognize. In addition, FIG. 5 is an observation of the back side of the nonwoven fabric, and the nonwoven fabric of Example 31 has adhesive peeling marks formed in the adhesive fibers on the back side of the nonwoven fabric, where the bonded areas by the adhesive fibers have been removed. I understand that.

Comparing Example 31 and Example 85, which use different cellulose fibers, Example 31 using Lyocell has higher breaking strength than Example 85 using cotton, with a strength of 10%, 20%, and 30% in the MD direction. The stress during elongation was high. In addition, Example 31 also had a high fuzz evaluation. Lyocell has extremely small variations in fineness and fiber length, and it is presumed that the nonwoven fabric has relatively good strength and fluff.

Furthermore, when comparing Example 31 and Example 86, which use different cellulose fibers, Example 31 using Lyocell has higher breaking strength than Example 86 using water-repellent rayon, by 10%, 20%, The stress was high at 30% elongation. In addition, Example 31 also had a high fuzz evaluation. Lyocell, which has a sedimentation speed of about 4 seconds, is more entangled by columnar water currents than water-repellent rayon, so it is presumed that this is why the nonwoven fabric has relatively good strength and fluff. On the other hand, Example 86 had lower maximum frictional force and kinetic frictional force than Example 31, and had relatively good slipperiness on the surface of the nonwoven fabric.

Comparing Example 31 and Example 84 in which the sheath components of the adhesive fibers were different, Example 84 had high stress at 10%, 20%, and 30% elongation in the MD direction. It is presumed that the strength of the nonwoven fabric is improved by using a resin with high adhesiveness to cellulose fibers, such as ethylene-acrylic acid copolymer, as the sheath component.

When comparing Example 82 and Example 83, which have a laminated structure and have a slightly different method of manufacturing the nonwoven fabric, Example 83 had a better fluff evaluation. The layer to which the hot air was applied tends to have a lower fiber density than the layer on the opposite side (the layer in contact with the support), and entanglement by the columnar water flow is relatively advanced. On the other hand, since the layer on the opposite side is relatively difficult to entangle, it is presumed that the higher the content of cellulose fibers in the layer on the opposite side, the more strongly the entanglement will occur and the less likely it will become fluffy.

The present disclosure includes the following aspects.
(Aspect 1)
A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined part of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
The adhesive intersection index A of the nonwoven fabric is 1 to 60 pieces/mm ² .
Non-woven fabric.
(Aspect 2)
A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined part of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
The thickness reduction rate of the nonwoven fabric is 30 to 45%,
Non-woven fabric.
(Aspect 3)
The nonwoven fabric according to any one of aspects 1 or 2, containing 25 to 75% by mass of the cellulose fibers.
(Aspect 4)
A method for producing a nonwoven fabric containing cellulose fibers and adhesive fibers, the method comprising: an adhesion step of adhering fibers to each other using the adhesive fibers; and an entangling step of intertwining the fibers after the adhesion step. Production method.
(Aspect 5)
The method for producing a nonwoven fabric according to aspect 4, including a cooling step between the bonding step and the entangling step.
(Aspect 6)
The method for producing a nonwoven fabric according to aspect 4 or 5, wherein the entangling step includes hydroentangling treatment.
(Aspect 7)
The method for producing a nonwoven fabric according to aspect 6, wherein the bonding step includes hot air processing, and the hydroentangling step includes spraying a columnar water stream first from the side to which the hot air is blown.
(Aspect 8)
According to aspect 6 or 7, the method includes a drying step after the hydroentangling treatment, and the temperature of the drying step is 10° C. or more lower than the softening or melting temperature of the adhesive component of the adhesive fiber. Method of manufacturing nonwoven fabric.
(Aspect 9)
comprising a drying step after the hydroentangling treatment,
The adhesive fibers include two or more adhesive fibers whose adhesive components have different melting points or softening points,
The melting point or softening point T ₁ (°C) of the thermal adhesive component with a higher melting point or softening point, the melting point or softening point T ₂ (°C) of the thermal adhesive component with a lower melting point or softening point, and the drying temperature T ( C) satisfies the relationship of _T2 ≦T< _T1 .

The nonwoven fabric of the present disclosure alleviates and preferably solves at least one of the problems such as insufficient fuzz control and hard texture, and can be used in applications that come into direct contact with human skin, such as absorbent articles. be able to.

Related Applications This application claims priority based on Article 4 of the Paris Convention, based on application number 2018-018501 filed in Japan on February 5, 2018. The contents of this basic application are incorporated herein by reference.

Claims (9)

A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined portion of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
The adhesive intersection index A of the nonwoven fabric is 1 to 60 pieces/mm ² .
Non-woven fabric. A nonwoven fabric containing cellulose fibers and adhesive fibers,
Including a bonding point between the adhesive fiber and the cellulose fiber and/or the adhesive fiber,
Including an intertwined part of the cellulose fiber with the cellulose fiber and/or the adhesive fiber,
The thickness reduction rate of the nonwoven fabric is 30 to 45%,
Non-woven fabric. The nonwoven fabric according to claim 1 or 2, wherein the cellulose fiber is contained in an amount of 25 to 75% by mass. A method for producing a nonwoven fabric containing cellulose fibers and adhesive fibers, the method comprising: an adhesion step of adhering fibers to each other using the adhesive fibers; and an entangling step of intertwining the fibers after the adhesion step. Production method. The method for manufacturing a nonwoven fabric according to claim 4, comprising a cooling step between the bonding step and the entangling step. The method for manufacturing a nonwoven fabric according to claim 4 or 5, wherein the entangling step includes hydroentangling treatment. 7. The method for producing a nonwoven fabric according to claim 6, wherein the bonding step includes hot air processing, and the hydroentangling step includes spraying a columnar water stream first from the side to which the hot air is blown. 8. A drying step is included after the hydroentangling treatment, and the temperature of the drying step is 10° C. or more lower than the softening or melting temperature of the adhesive component of the adhesive fiber. method for producing nonwoven fabric. comprising a drying step after the hydroentangling treatment,
The adhesive fibers include two or more adhesive fibers whose adhesive components have different melting points or softening points,
The melting point or softening point T ₁ (°C) of the adhesive component with a higher melting point or softening point, the melting point or softening point T ₂ (°C) of the adhesive component with a lower melting point or softening point, and the temperature T (°C) of the drying process. The method for manufacturing a nonwoven fabric according to claim 6 or 7, wherein: T ₂ ≦T < T ₁ .