JP7733437B2 - Nonwoven fabric, its manufacturing method, and wiper - Google Patents

Description

This disclosure relates to a nonwoven fabric, a method for manufacturing the same, and a wiper including the nonwoven fabric.

One use of nonwoven fabrics is in wipers used to wipe dirt off people's bodies or objects. Wiper configurations vary widely. For example, Patent Document 1 proposes a composite sheet suitable for cleaning, in which protrusions made of nonwoven fabric are fixed in ridges on a nonwoven fabric, and when viewed in a cross section of the composite sheet perpendicular to the ridges, at least some of the protrusions have a hook-shaped cross-sectional structure, and the protrusions with the hook-shaped cross-sectional structure continue for 3 to 20 cm along the ridges. Furthermore, Patent Document 2 proposes a nonwoven fabric for use as a wiping material in which the constituent fibers are entangled by needle punching, with the remaining portions forming first entangled sections, and the constituent fibers at predetermined locations on the nonwoven fabric being entangled to form second entangled sections, the first entangled sections and the second entangled sections being present in multiple rows spaced apart from each other, the first entangled sections having a relatively lower fiber density than the second entangled sections, and when observed from a cross section, the first entangled sections protruding beyond the second entangled sections on at least one surface of the nonwoven fabric.

Japanese Patent Application Laid-Open No. 2000-212879 JP 2011-117095 A

For example, when used as a wiper, the nonwoven fabric is resistant to pilling and tearing due to the force applied when rubbing against a person's body or an object to remove dirt, or when attached to a jig, and has excellent dirt collection properties. The present invention provides a method for producing such a nonwoven fabric, and a nonwoven fabric produced by this method.

In a first aspect, the present disclosure provides a method for producing a nonwoven fabric containing cellulosic fibers and adhesive fibers, the method comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
The present invention provides a method for producing a nonwoven fabric, which includes a partial entanglement step in which the entanglement step forms highly entangled sections, in which the degree of entanglement between fibers is higher, and low entangled sections, in which the degree of entanglement between fibers is lower than that of the highly entangled sections, so that the highly entangled sections and the low entangled sections are alternately arranged in a planar view and the low entangled sections have a width of 2 mm or more and 50 mm or less.

In a second aspect, the present disclosure provides a nonwoven fabric comprising a cellulosic fiber and an adhesive fiber,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In a third aspect, the present disclosure provides a wiper comprising the nonwoven fabric according to the second aspect.

In a fourth aspect, the present disclosure provides a method for producing a nonwoven fabric including a fiber layer containing cellulosic fibers and adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, the method comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step;
A method for producing a nonwoven fabric is provided.

In a fifth aspect, the present disclosure provides a nonwoven fabric including a fiber layer including a cellulosic fiber and an adhesive fiber, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In a sixth aspect, the present disclosure provides a wiper including the nonwoven fabric according to the fifth aspect.

In a seventh aspect, the present disclosure provides a method for producing a nonwoven fabric containing adhesive fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
A method for producing a nonwoven fabric is provided.

In an eighth aspect, the present disclosure provides a method for producing a nonwoven fabric including a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, the method comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step;
A method for producing a nonwoven fabric is provided.

In a ninth aspect, the present disclosure provides a nonwoven fabric comprising adhesive fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In a tenth aspect, the present disclosure provides a nonwoven fabric including a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In an eleventh aspect, the present disclosure provides a wiper including the nonwoven fabric according to the ninth or tenth aspect above.

In the manufacturing method of the present disclosure, fibers are bonded together using adhesive fibers, and the fiber web is then subjected to an entanglement process that includes a partial entanglement process. As a result, the resulting nonwoven fabric is relatively bulky and has a relatively high degree of fiber freedom, particularly in the low entanglement sections. In the highly entangled sections, the fibers are relatively strongly entangled, resulting in relatively high strength. Furthermore, by bonding the fibers together, the resulting nonwoven fabric is less likely to pill. Wipers containing nonwoven fabric obtained by the manufacturing method of the present disclosure are relatively bulky and exhibit excellent dirt collection capabilities in the low entanglement sections, where the degree of fiber freedom is relatively high. In the highly entangled sections, where the fibers are relatively strongly entangled, the strength of the entire wiper is ensured. Furthermore, because the fibers are bonded together, pilling is less likely to occur.

FIG. 1 is a perspective view showing an example of a nonwoven fabric produced by carrying out a hydroentangling treatment using a nozzle 1) as a partial entangling step. FIG. 1 is a perspective view showing an example of a nonwoven fabric produced by carrying out a hydroentanglement treatment using a nozzle 2) as a partial entanglement step.

(Background to the manufacturing method of the present disclosure)
The present inventors have discovered that when a nonwoven fabric is used as a wiper, increasing the degree of freedom of the fibers in the nonwoven fabric and increasing the bulk of the nonwoven fabric improves its dirt collection ability. A common method for obtaining a bulky nonwoven fabric is to subject the fibers to a bonding treatment (e.g., hot air processing) without applying pressure using adhesive fibers. However, if the nonwoven fabric obtained by this method contains a high proportion of adhesive fibers, the fibers are bonded and fixed, reducing the degree of freedom of the fibers, resulting in insufficient dirt wiping and collection capabilities. The degree of freedom of the fibers in the nonwoven fabric can be increased by mixing non-adhesive fibers. However, since non-adhesive fibers reduce the strength of the nonwoven fabric and tend to cause fuzzing on the surface of the nonwoven fabric when rubbed against an object or the body, mixing non-adhesive fibers tends to make it difficult to obtain a practical wiper.

One known method for producing nonwoven fabrics is to entangle fibers, as described in Patent Document 2. In nonwoven fabrics in which the fibers are entangled, the fibers are not bonded, allowing for a relatively high degree of freedom, and by adjusting the degree of entanglement, a flexible nonwoven fabric can be obtained. However, if the degree of entanglement of the fibers is increased in order to improve the strength of the nonwoven fabric, the bulk of the nonwoven fabric decreases, resulting in a decrease in its ability to capture dirt.

Fuzzing is also likely to occur in nonwoven fabrics where the fibers are simply entangled. One way to prevent this is to mix adhesive fibers into the fiber web and then use the adhesive fibers to bond the fibers together after entangling the fibers. However, this inevitably reduces the flexibility of the fibers, further reducing their ability to wipe or collect dirt.

Therefore, the present inventors have investigated a method for producing a nonwoven fabric that achieves both bulkiness and high fiber flexibility. They produced a nonwoven fabric by subjecting a fiber web containing adhesive fibers, specifically a fiber web containing a mixture of adhesive fibers and non-adhesive cellulosic fibers, to a bonding step to fix the fibers to a certain extent, and then subjecting the fiber web to a partial entanglement step. As a result, they were able to obtain a nonwoven fabric that was bulkier, had a higher fiber flexibility, and was less prone to pilling than a nonwoven fabric produced by first performing the entanglement step and then the bonding step.
The method for producing the nonwoven fabric of the present disclosure will be described below.

[Embodiment 1]
A method for producing a nonwoven fabric according to a first embodiment of the present disclosure includes:
A method for producing a nonwoven fabric comprising cellulosic fibers and adhesive fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and low entangled portions, in which the degree of entanglement between fibers is lower than that of the belt-like portions or the streak-like portions, so that the highly entangled portions and the low entangled portions are alternately arranged in a plan view and the width of the low entangled portions is 2 mm or more and 50 mm or less;
A method for manufacturing nonwoven fabric.

This manufacturing method uses a fiber web containing cellulosic fibers and adhesive fibers. Therefore, the following description will first discuss the cellulosic fibers and adhesive fibers.

(cellulosic fiber)
"Cellulosic fibers" are also called cellulose fibers and generally refer to fibers made from cellulose.
Cellulosic fibers include, for example:
(1) Natural fibers derived from plants such as cotton, flax, flax, ramie, jute, banana, bamboo, kenaf, shell ginger, hemp, and kapok;
(2) Regenerated fibers such as viscose-based rayon and polynosic rayon, cupra obtained by the cuprammonium method, and Tencel (registered trademark) and Lyocell (registered trademark) obtained by solvent spinning;
(3) cellulose fibers obtained by melt spinning; and (4) semi-synthetic fibers such as acetate fibers. The type of cellulosic fiber is not particularly limited.

The fineness of the cellulosic fibers may be, for example, 0.6 dtex to 5.6 dtex, particularly 1.0 dtex to 4.4 dtex, and more particularly 1.4 dtex to 3.3 dtex.
When the fineness of the cellulose-based fiber is within the above-mentioned range, the strength of the nonwoven fabric and the suppression of fluffing can be made appropriate, and the bulkiness of the nonwoven fabric is also good. The fineness of the cellulose-based fiber affects the entanglement of the fibers, and when the fineness of the cellulose-based fiber is within the above-mentioned range, the degree of entanglement is made appropriate. If the degree of entanglement is too high, the bulkiness of the nonwoven fabric may decrease, and if the degree of entanglement is too low, the strength may decrease and fluffing may occur significantly.

The fiber diameter of the cellulosic fibers may be, for example, 5 μm to 25 μm, particularly 8 μm to 20 μm, and more particularly 10 μm to 17 μm.
When the fiber diameter of the cellulose-based fiber is within the above-mentioned range, the strength and fuzzing of the nonwoven fabric can be appropriately suppressed, and the bulkiness of the nonwoven fabric is also good. The fiber diameter of the cellulose-based fiber also affects the entanglement of the fibers, and when the fiber diameter of the cellulose-based fiber is within the above-mentioned range, the degree of entanglement is appropriate. If the degree of entanglement is too high, the bulkiness of the nonwoven fabric may decrease, and if the degree of entanglement is too low, the strength may decrease and fuzzing may occur significantly.

The fiber length of the cellulosic fibers may be, for example, 25 mm to 100 mm, particularly 30 mm to 70 mm, and more particularly 35 mm to 60 mm.
When the fiber length of the cellulosic fiber is within the above range, the entanglement of the fiber is likely to be favorable. In particular, in the manufacturing method of this embodiment, when the fiber length is within the above range, a more appropriate number of bonded points can be formed on each fiber in the bonding step.

The cross section of the cellulosic fiber (the cross section, or the cross section perpendicular to the length of the fiber) may be circular or non-circular. Examples of non-circular shapes include oval, Y-shaped, X-shaped, square, multi-lobed, polygonal, star-shaped, and chrysanthemum-shaped. When the fiber cross section is circular, the adhesion area with the adhesive fiber is relatively small, allowing for greater freedom of fiber in the nonwoven fabric than when fibers with a non-circular shape are used. When the fiber cross section is non-circular, the adhesion area with the adhesive fiber is relatively large, allowing for greater suppression of pilling in the nonwoven fabric and greater strength of the nonwoven fabric.

As the cellulose-based fiber, chemical fibers such as regenerated fibers or semi-synthetic fibers may be used. The variations in fineness and/or fiber diameter, as well as fiber length, of chemical fibers are smaller than those of natural fibers, making it easier to adjust the degree of entanglement of the nonwoven fabric. Furthermore, regenerated fibers such as rayon and solvent-spun cellulose fibers have a good balance of softness and strength when wet, making it easier to obtain suitable softness and strength for the nonwoven fabric, and are therefore preferred. Furthermore, solvent-spun cellulose fibers have a relatively high single fiber strength, making them preferable in that they suppress fuzzing of the nonwoven fabric and improve the strength of the nonwoven fabric.
The 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. Surface treatment generally involves attaching an oil (surfactant) to the fiber surface. The degree of hydrophilicity or hydrophobicity of the surface of cellulosic fibers can be evaluated using values such as the sedimentation rate of the fibers. Surface treatment may increase the hydrophilicity of the surface (hydrophilization treatment), or decrease the hydrophilicity of the surface (hydrophobization treatment).

The settling velocity (or settling time (seconds)) of the cellulosic fibers used in this embodiment may be, for example, 30 seconds or less, particularly 20 seconds or less, and more particularly 10 seconds or less. The lower the settling velocity (or settling time) of the cellulosic fibers, the higher the degree of entanglement of the cellulosic fibers tends to be.

The settling velocity of the fibers can be measured by the following method.
17 g of fibers for measuring the sedimentation rate were collected. The collected fibers were opened (using a parallel carding machine) to form a carded web. 5 g of the carded web was weighed and packed into a cage (cylindrical, 5 cm diameter, 8 cm height, 3 g mass) made of copper wire (0.55 mm diameter).
Next, prepare a thermostatic water bath, fill it with tap water, and set it to 25°C. Once the water temperature reaches 25°C, stop stirring the thermostatic water bath and begin measuring the sedimentation rate. The basket filled with fibers using the above procedure is gently dropped from a position 1 cm above the water surface, and the stopwatch is started as soon as the basket hits the water surface. The fibers gradually absorb water, and the stopwatch is stopped as soon as the 8 cm high basket completely sinks below the water surface. The sedimentation rate is the time from when the basket hits the water surface to when it sinks below the water surface, and the average of the two measurements is taken as the sedimentation rate of the fiber.

When measuring the sedimentation rate, if the basket does not sink below the water surface for 5 minutes or more, the fibers are considered to be water-repellent. Water-repellent cellulosic fibers may be preferable in applications where the nonwoven fabric comes into contact with liquid. For example, in top sheets and second sheets for absorbent articles, water-repellent cellulosic fibers may be preferable because they facilitate the transfer of liquid to the absorbent body without retaining too much liquid within the sheet. When the nonwoven fabric has a laminated structure, using a laminated nonwoven fabric having a layer containing water-repellent cellulosic fibers and a layer containing non-water-repellent cellulosic fibers allows the nonwoven fabric to transfer or retain liquid effectively in applications such as sheets for absorbent articles and liquid-impregnated skin coverings impregnated with liquids such as cosmetics.

(Adhesive Fiber)
Next, adhesive fibers will be described.
The term "adhesive fiber" refers to a fiber that exhibits adhesiveness through a bonding treatment (e.g., thermal bonding treatment, electron beam irradiation, ultrasonic welding (ultrasonic welder), etc.) and can bond fibers together to form bonded portions, and is not particularly limited as long as the nonwoven fabric intended 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, and examples thereof include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof; polyolefin-based resins such as polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene copolymers containing propylene as the main component (including propylene-ethylene copolymer and propylene-butene-1-ethylene copolymer), ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer; polyamide-based resins such as nylon 6, nylon 12, and nylon 66; acrylic resins; engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefin, as well as elastomers thereof. Synthetic fibers may be produced using one or more thermoplastic resins arbitrarily selected from these.

Synthetic fibers may be single fibers made of one or more thermoplastic resins selected from the above, or may be composite fibers made of two or more components (also known as "sections"). In composite fibers, each component may be made of a single thermoplastic resin, or a mixture of two or more thermoplastic resins. Composite fibers may be, for example, sheath-core composite fibers, islands-in-the-sea composite fibers, or side-by-side composite fibers. Sheath-core composite fibers may be eccentric sheath-core composite fibers in which the centers of the core and sheath components do not coincide in the fiber cross section, or concentric sheath-core composite fibers in which the centers of the core and sheath components coincide in the fiber cross section.

Synthetic fibers, whether single or composite, may have a modified cross section. In the case of sheath-core and islands-in-sea composite fibers, the core and/or island components may have a modified cross section in the fiber cross section.
When the synthetic fiber has a non-circular cross section, the cross section may be elliptical, polygonal, star-shaped, or a shape in which multiple protrusions are joined at their bases (for example, cloverleaf 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 the thermoplastic resin with a lower melting point forms part of the fiber surface. The thermoplastic resin with a low melting point (low-melting component) melts or softens when heat is applied during the process of producing a nonwoven fabric, becoming an adhesive component. The low-melting component contributes to the adhesion of fibers to each other or to other members, and can form adhesive sites.
When the synthetic fiber is a composite fiber, the low-melting point component is preferably exposed over 40% or more of the circumferential length of the fiber in the cross section, more preferably over 50% or more, even more preferably over 60% or more, even more preferably over 80% or more, and particularly preferably over the entire circumferential length of the fiber.

In this embodiment, a nonwoven fabric is produced by performing an entanglement process after the bonding process. The proportion of the length of the low-melting-point component of the adhesive fiber exposed on the circumferential surface of the fiber in the fiber cross section (hereinafter referred to as the "exposed length") affects the area of the bondable region and also the degree to which adhesion between fibers is resolved in the entanglement process. When the exposed length of the low-melting-point component of the adhesive fiber is within the above range, the area of the bondable region becomes appropriate, and the number of bonded points can be made appropriate. Furthermore, by appropriately easing adhesion between fibers in the subsequent entanglement, fuzzing can be further suppressed in the final nonwoven fabric, and its strength can be made sufficient. If the proportion of the exposed length is too small, the number of bonded points will be reduced, making the nonwoven fabric more susceptible to fuzzing or reducing the strength of the nonwoven fabric.

The adhesive component of the adhesive fiber may be a copolymer of an olefin and an unsaturated carboxylic acid or its derivative. Such a copolymer exhibits good adhesion to cellulosic fibers. Examples of unsaturated carboxylic acids include maleic acid, acrylic acid, methacrylic acid, fumaric acid, and itaconic acid. Examples of derivatives include anhydrides of unsaturated carboxylic acids, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, and dimethylaminoethyl methacrylate, as well as similar acrylic acid esters, glycidyl acrylate, glycidyl methacrylate, butenecarboxylic acid esters, allyl glycidyl ether, 3,4-epoxybutene, 5,6-epoxy-1-hexene, and vinylcyclohexene monoxide. An ethylene-acrylic acid copolymer in which the olefin is ethylene and the unsaturated carboxylic acid or its derivative is acrylic acid or its derivative is particularly preferred.

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

When the adhesive fiber is a sheath-core composite fiber in which a thermoplastic resin with a lower melting point constitutes the sheath portion, core/sheath combinations include, for example, polyethylene terephthalate/polyethylene, polyethylene terephthalate/polypropylene, polyethylene terephthalate/propylene copolymer, polytrimethylene terephthalate/polyethylene, polybutylene terephthalate/polyethylene, polyethylene terephthalate/copolymer polyester (e.g., polyethylene terephthalate copolymerized with isophthalic acid), polypropylene/ethylene-acrylic acid copolymer, and polylactic acid/polybutylene succinate. These combinations can also be applied to composite fibers other than sheath-core composite fibers. Sheath-core composite fibers in which the sheath is polyethylene (e.g., high-density polyethylene, low-density polyethylene, or linear low-density polyethylene) or copolymer polyester have the property that, when heat-treated at a temperature above the melting point of the thermoplastic resin constituting the sheath, the sheath melts or softens, bonding the fibers together and forming bonding sites.

The thermoplastic resins exemplified as constituent components of the single fiber or composite fiber may contain other components as long as they contain 50% by mass or more of the specifically specified thermoplastic resin. For example, in the combination of polyethylene/polyethylene terephthalate, the "polyethylene" may contain other thermoplastic resins and additives, etc., as long as it contains 50% by mass or more of polyethylene. This also applies to the examples below.

When the adhesive fiber is a core-sheath composite fiber, the core-to-sheath composite ratio (volume ratio, core/sheath) may be, for example, 80/20 to 20/80, and particularly 60/40 to 40/60. When the core/sheath composite ratio is within this range, the fibers are bonded appropriately, resulting in a nonwoven fabric with appropriate strength and reduced fuzzing. Furthermore, when the core/sheath composite ratio is within this range, excessive peeling at the bonded points does not occur during the entangling process. Furthermore, when the core/sheath composite ratio is within this range, the fiber shape is easily maintained by the core component, allowing for suitable strength of the nonwoven fabric.

Two or more fibers may be included as adhesive fibers. In such cases, the melting points of the adhesive components of these fibers may differ from each other. For example, when two types of adhesive fibers are included, the difference in melting points between the adhesive components of these fibers may be 10°C or more and 40°C or less, and particularly 15°C or more and 30°C or less.

The fineness of the adhesive fiber may be, for example, 1.0 dtex to 7.8 dtex, particularly 1.4 dtex to 6.7 dtex, and more particularly 2.2 dtex to 4.5 dtex.
When the fineness of the adhesive fiber is within the above range, the resulting nonwoven fabric tends to have appropriate strength, reduced fluffing, and bulkiness.

The fiber diameter of the adhesive fiber may be, for example, 10 μm to 33 μm, particularly 12 μm to 30 μm, and more particularly 15 μm to 25 μm.
When the fiber diameter of the adhesive fiber is within the above range, the resulting nonwoven fabric tends to have appropriate strength, reduced fluffing, and bulkiness.

The fiber length of the adhesive fiber may be, for example, 25 mm to 100 mm, particularly 30 mm to 70 mm, and more particularly 35 mm to 60 mm.
When the fiber length of the adhesive fiber is within the above range, the entanglement of the fibers is likely to be favorable. In particular, in the manufacturing method of this embodiment, when the fiber length is within the above range, a more appropriate number of bonded points can be formed on one fiber in the bonding step.

The adhesive fibers may have three-dimensional crimps in the final nonwoven fabric. When the adhesive fibers have three-dimensional crimps, the resulting nonwoven fabric tends to be bulkier. Furthermore, when the adhesive fibers have three-dimensional crimps, it becomes easier to obtain a nonwoven fabric having a bond intersection index A and a bond intersection angle (the angle of the fiber bond intersections at either or both the upper and lower parts when the nonwoven fabric is divided into three equal parts in the thickness direction) that fall within a specific range, as described below. In this specification, the term "three-dimensional crimps" is used to distinguish them from mechanical crimps, in which the crimp peaks (or peaks) are at acute angles. Three-dimensional crimps include, for example, crimps with curved peaks (wave-shaped crimps), crimps with spirally curved peaks (helical crimps), crimps that are a mixture of wave-shaped crimps and spiral crimps, and crimps that are a mixture of acute-angled mechanical crimps and at least one of wave-shaped crimps and spiral crimps.
Alternatively, the adhesive fibers may have only mechanical crimp.

When the adhesive fiber is a composite fiber, it may also be a visibly crimped composite fiber. "Visibly crimped composite fiber" refers to a fiber that exhibits three-dimensional crimp at the fiber stage, and is different from latent crimped composite fiber, which exhibits three-dimensional crimp upon heat treatment.

The adhesive fiber having 3D crimp may be an eccentric core-sheath type composite fiber. In this case, the eccentricity may be, for example, 5% to 50%, and particularly 7% to 30%. The "eccentricity" here is defined by the following formula:
Eccentricity (%) = (distance between the center of the single fiber and the center of the core component) × 100 / (single fiber radius)

In this embodiment, the adhesive fiber does not necessarily have to be derived from so-called splittable conjugate fibers. Splittable conjugate fibers have a cross-sectional structure in which at least one of the constituent components is divided into two or more parts in the fiber cross section, at least a portion of which is exposed on the fiber surface and the exposed parts are continuously formed in the length direction of the fiber. Splittable conjugate fibers, for example, have wedge-shaped sections arranged in a chrysanthemum shape, or each section arranged in layers in the fiber cross section. Splittable conjugate fibers split one or more components (sections) due to external forces applied during the entanglement treatment, resulting in ultrafine fibers. When such splittable conjugate fibers are not included as adhesive fibers, the adhesion between fibers is good, making it easier to achieve appropriate strength and reduced fuzzing in the nonwoven fabric. Furthermore, when splittable conjugate fibers are not included as adhesive fibers, it is easier to increase the bulk of the ridges when forming the less entangled portions into ridges.

(Preparation of fiber web)
Next, the preparation of a fibrous web containing the above-mentioned cellulosic fibers and adhesive fibers will be described.
The fibrous web is produced by mixing cellulosic fibers and adhesive fibers. The blend ratio of the cellulosic fibers to the adhesive fibers (cellulosic fibers:adhesive fibers) (mass ratio) may be, for example, 10:90 to 90:10, particularly 20:80 to 80:20, more particularly 20:80 to 60:40, even more particularly 20:80 to 55:45, even more particularly 20:80 to 45:55, and even more particularly 25:75 to 35:65. When the blend ratio of the cellulosic fibers to the adhesive fibers is within the above range, the resulting nonwoven fabric is bulky, while easily achieving appropriate strength and reduced fuzzing.

Cellulosic fibers are used as non-adhesive fibers, allowing for a certain degree of freedom in the fibers of the nonwoven fabric. Furthermore, cellulose fibers exhibit high entanglement properties, particularly when the entanglement process is carried out as a hydroentanglement process, and are well entangled even at low water pressure, ensuring the strength of the nonwoven fabric. Therefore, if the proportion of cellulose fibers is too small, the strength of the nonwoven fabric may decrease, or it may not exhibit good dirt collection properties when used as a wiper.

By bonding fibers together, the adhesive fibers ensure the bulkiness of the resulting nonwoven fabric and also suppress fuzzing. As described below, in this embodiment, a fiber web with very weak fiber entanglement is first subjected to the bonding process. Therefore, after the bonding process, the fiber web is in a relatively bulky state, with the fibers bonded to each other. When this fiber web is then subjected to the entanglement process, the bonded areas formed by the adhesive fibers resist the loss of bulk caused by the entanglement process, compared to when the fiber web is directly subjected to the entanglement process, resulting in a bulky nonwoven fabric. Furthermore, by fixing the fibers together, the adhesive fibers also suppress fuzzing. Therefore, if the proportion of adhesive fibers is too small, the nonwoven fabric may not be able to achieve sufficient bulkiness. Furthermore, if the proportion of adhesive fibers is too small, the strength of the fiber web before the entanglement process will be reduced and it will be more likely to stretch, resulting in insufficient processability of the fiber web. Furthermore, if the proportion of adhesive fibers is too small, fuzzing may be more likely to occur.

The fiber web may contain fibers other than cellulosic fibers and adhesive fibers (hereinafter referred to as "other fibers"). Examples of other fibers include natural fibers that are not cellulosic fibers (such as wool and silk) and synthetic fibers that are not adhesive fibers (such as synthetic fibers that do not melt or soften when the adhesive component of the adhesive fiber is melted, and do not exhibit adhesive properties), and are not particularly limited.

The other fibers may be contained in an amount of 35% by mass or less, particularly 25% by mass or less, and more particularly 10% by mass or less, when the total amount of fibers constituting the fiber web is 100% by mass.
In this embodiment, the fibrous web may contain no other fibers and may consist only of cellulosic fibers and adhesive fibers.

Alternatively, the fiber web may be composed primarily of adhesive fibers and other fibers that are not cellulosic fibers, or may be composed solely of adhesive fibers. In such a fiber web, the blend ratio of the other fibers to the adhesive fibers (other fibers:adhesive fibers) (mass ratio) may be, for example, 0:100 to 90:10, particularly 0:100 to 80:20, and more particularly 0:100 to 60:40. When the blend ratio of the other fibers to the adhesive fibers is within the above range, the resulting nonwoven fabric is bulky while easily achieving appropriate strength and reduced fuzzing. In addition to the other fibers and adhesive fibers, this fiber web may contain cellulosic fibers, which may be present in a proportion of 10% by mass or less, when the total fibers constituting the fiber web is taken as 100% by mass.

The fiber web can be produced by known methods. The fiber web may be in any form, such as a parallel web, cross web, carded web (e.g., a semi-random web or random web), air-laid web, or wet-laid web. A parallel web is preferred as this results in a smoother surface for the nonwoven fabric.

The fiber web may have, for example, a basis weight of 10 g/m ² to 150 g/m ² , particularly a basis weight of 15 g/m ² to 120 g/m ² , more particularly a basis weight of 30 g/m ² to 100 g/m ² , and even more particularly a basis weight of 40 g/m ² to 80 g/m ^2. Since the basis weight of the fiber web is approximately the same as the basis weight of the resulting nonwoven fabric, if the basis weight of the fiber web is within the above range, a soft nonwoven fabric with excellent bulkiness and fuzz suppression can be obtained. If the basis weight is too small, it may be difficult to obtain a bulky nonwoven fabric, and if the basis weight is too large, the strength of the nonwoven fabric may decrease or fuzz may be more likely to occur.

Preparing the fiber webs may include, for example, preparing fiber web A and fiber web B separately. In this case, as described below, for example, fiber web A may be subjected to a bonding process, and then fiber web B may be laminated thereon, and the two laminated fiber webs may be subjected to an entanglement process. When producing a nonwoven fabric using this method, fiber web A and fiber web B may be identical. Alternatively, fiber web A and fiber web B may differ from each other in at least one of the following: the type of cellulosic fiber and/or adhesive fiber, the ratio of cellulosic fiber to adhesive fiber, the shape, and the basis weight. Alternatively, fiber web B may contain only cellulosic fibers without containing adhesive fibers. As long as the combined whole of fiber webs A and B contains cellulosic fibers and adhesive fibers, there are no particular restrictions on the proportions of cellulosic fibers and adhesive fibers in each of the fiber webs. For example, fiber web B, which is a fiber web separate from fiber web A, may contain adhesive fibers in an amount of 20% by mass or more and 80% by mass or less.

For example, fiber web A may be a parallel web made of a mixture of rayon fibers and adhesive fibers in a ratio of 70:30 (by mass), and fiber web B may be a random web made of a mixture of solvent-spun cellulose fibers and adhesive fibers in a ratio of 80:20 (by mass). In this case, fiber webs A and B may have the same basis weight, or may have different basis weights. When two or more fiber webs are laminated, the basis weight of each fiber web is determined so that the resulting nonwoven fabric has the desired basis weight.

Fiber web A and/or fiber web B may be mainly composed of adhesive fibers alone, or adhesive fibers and fibers other than cellulosic fibers. The specific configuration of fiber webs A and B mainly composed of adhesive fibers and other fibers is described above with "cellulosic fibers" replaced with "other fibers."
Alternatively, one of the fibrous webs A and B may be a web mainly composed of adhesive fibers only or adhesive fibers and cellulosic fibers, and the other may be a fibrous web containing adhesive fibers and cellulosic fibers.

When fiber web A and fiber web B are prepared separately, one fiber web may have, for example, a basis weight of 5 g/m ² to 75 g/m ² , particularly a basis weight of 10 g/m ² to 60 g/m ² , more particularly a basis weight of 15 g/m ² to 50 g/m ² , and even more particularly a basis weight of 20 g/m ² to 40 g/m ² .
Preparing the fibrous web may include separately preparing three or more fibrous webs on three or more web manufacturing lines.

Furthermore, a nonwoven fabric containing other fibers and/or cellulosic fibers may be prepared and layered separately from the fiber web. Alternatively, a mesh sheet may be prepared and layered separately from the fiber web. The other nonwoven fabric or mesh sheet (hereinafter collectively referred to as the "substrate sheet") prepared separately from the fiber web may exist as an independent sheet, with the fibers already integrated by entanglement, adhesion, or the like. The substrate sheet can be integrated with the fiber web by entanglement of the fibers, and when the substrate sheet is sandwiched between two fiber webs as described below, the fibers are entangled between the two fiber webs via the substrate sheet. Therefore, it is preferable that the substrate sheet have voids or openings that allow for entanglement of the fibers.

Examples of the substrate sheet include nonwoven fabrics such as long fiber nonwoven fabrics (for example, spunbond nonwoven fabrics), meltblown nonwoven fabrics, airlaid nonwoven fabrics, and wetlaid nonwoven fabrics, and mesh sheets.
The long-fiber nonwoven fabric may be a composite sheet of a sheet with threads aligned in the longitudinal direction and a sheet with threads aligned in the transverse direction, or a sheet obtained by laminating and integrating two or more net-like webs formed by splitting and stretching a film. Examples of such sheets that may be used include MILIFE (registered trademark) manufactured by JX ANCI Corporation and WARIF (registered trademark) manufactured by JX ANCI Corporation.
When the base sheet is a long-fiber nonwoven fabric, the density of the long-fiber nonwoven fabrics exemplified above is relatively low, that is, the voids in the nonwoven fabric are relatively large, so that the entanglement of the fibers and the mechanical properties of the nonwoven fabric tend to be compatible.

The nonwoven fabric may be made by laminating two or more types of nonwoven fabric. For example, the nonwoven fabric may be a laminated nonwoven fabric in which a spunbond nonwoven fabric and a meltblown nonwoven fabric are laminated and integrated. The spunbond nonwoven fabric may be made of synthetic fibers with a fineness of 0.5 dtex to 7.0 dtex, in particular 1.0 dtex to 4.0 dtex (the types of thermoplastic resins that can be used to make the synthetic fibers are as described above). The meltblown nonwoven fabric may be made of synthetic fibers with a fineness of 0.005 dtex to 1.0 dtex, in particular 0.007 dtex to 0.7 dtex.

Reticulated sheets include scrims and nets made by biaxially stretching thermoplastic resins. Examples of reticulated sheets that may be used include ConwedNet (registered trademark) manufactured by Conwed Global Netting Solutions, Inc., USA. Reticulated sheets have a particularly good balance between void size and high mechanical properties, making it easier to carry out the entanglement process between fibers in a fiber web or between fiber webs via a base sheet under milder conditions than when using other base sheets. Milder conditions, for example, mean lower liquid flow pressure when the entanglement process is a high-pressure liquid flow treatment using a liquid flow.

Wetlaid nonwoven fabrics include tissue (also called tissue paper) containing pulp fibers, with the fibers bonded together by a binder and/or hydrogen bonds. Pulp fibers include mechanical pulp, recycled pulp, and chemical pulp. Wood pulp or non-wood pulp may be used as the pulp fiber, and any wood pulp produced by conventional methods using softwood or hardwood can be used. Wetlaid nonwoven fabrics are less likely to inhibit entanglement of fibers between fiber webs and wetlaid nonwoven fabrics, and between two fiber webs, and improve the mechanical properties of the nonwoven fabric.

Laminating a base sheet to a fiber web tends to improve the mechanical properties of the nonwoven fabric, particularly the stress at 10% elongation. Therefore, when a nonwoven fabric is constructed using only a fiber web, the bonding process after the entanglement process, which is required to achieve the desired mechanical properties, can sometimes be omitted when a base sheet is used.

The substrate sheet may have a basis weight of, for example, 5 g/m ² to 30 g/m ² , particularly 7 g/m ² to 25 g/m ² , and more particularly 10 g/m ² to 20 g/m ^2. The substrate sheets exemplified above are generally thin and low in bulk, so if the basis weight is large, the proportion of the fiber layer containing cellulosic fibers and adhesive fibers in a nonwoven fabric of a given basis weight will decrease, resulting in a decrease in the bulk of the nonwoven fabric and reduced wiping performance. Furthermore, if the basis weight of the substrate sheet is too large, the upper and lower fiber layers may not be sufficiently entangled, particularly when the nonwoven fabric is configured with fiber layers containing cellulosic fibers and adhesive fibers arranged above and below the substrate sheet.

The density of the substrate sheet (under a load of 1.96 kPa) may be, for example, 0.005 g/cm ³ or more and 0.20 g/cm ³ or less, and particularly 0.010 g/cm ³ or more and 0.15 g/cm ³ or less.
When the base sheet is a long-fiber nonwoven fabric, the long-fiber nonwoven fabric may have a density (under a load of 1.96 kPa) of, for example, 0.050 g/cm ³ or more and 0.20 g/cm ³ or less, and particularly 0.070 g/cm ³ or more and 0.15 g/cm ³ or less.

When the base sheet is a mesh sheet with regular openings (e.g., rectangular or square shapes defined by filaments), the opening dimensions may be, for example, 3 mm or more, particularly 4 mm or more, and more particularly 5 mm or more. The upper limit of the opening dimensions may be, for example, 15 mm, particularly 12 mm. The opening dimension is the length of the longest line segment connecting any two points on the outline defining the opening. If the opening dimensions are too small, the upper and lower fiber layers may be insufficiently entangled, particularly when the nonwoven fabric is configured with fiber layers containing cellulosic fibers and adhesive fibers arranged above and below the base sheet. As a result, delamination may occur more easily, or the pattern may become unclear if a pattern is formed in the highly entangled portions. A mesh sheet with regular openings may have an opening ratio of 50% to 99%, particularly 60% to 98%, and more particularly 70% to 97%. When the opening ratio is within this range, entanglement with the fibers tends to be good, and when fiber layers are positioned on both sides, it is easier to ensure good entanglement of the fibers between the fiber layers.

The base sheet may, for example, have a stress at 10% elongation of 2.0 N/5 cm or more in the MD direction and 0.5 N/5 cm or more in the CD direction. The stress at 10% elongation of the base sheet may particularly be 2.2 N/5 cm or more in the MD direction and 0.7 N/5 cm or more in the CD direction, more particularly 2.5 N/5 cm or more in the MD direction and 1.0 N/5 cm or more in the CD direction. The upper limit of the stress at 10% elongation of the base sheet may, for example, be 20 N/5 cm in the MD direction and 20 N/5 cm in the CD direction. A base sheet whose stress at 10% elongation is within the above ranges can improve the handleability of the nonwoven fabric.

When producing a nonwoven fabric containing a base sheet, the process of laminating the base sheet onto a fiber web containing cellulosic fibers and adhesive fibers may be carried out before or after the bonding process described below. Furthermore, after the bonding process, another fiber web containing cellulosic fibers and adhesive fibers may be laminated onto a composite web formed by laminating a base sheet onto a fiber web. In this specification, the process of laminating a base sheet onto a fiber web is conveniently referred to as the "base sheet laminating process," and the process of laminating another fiber web onto a fiber web or composite web is conveniently referred to as the "web laminating process." For example, the process of preparing fiber web A and fiber web B as described above, and laminating fiber web B onto fiber web A, and the process of laminating a base sheet onto fiber web A and then laminating fiber web B correspond to web laminating processes.

If the base sheet lamination step is performed before the bonding step, the fiber web and base sheet may be bonded during the bonding step, which tends to result in a nonwoven fabric with improved mechanical properties. If the base sheet lamination step is performed after the bonding step, entanglement of the fibers tends to progress more during the subsequent entanglement step. Furthermore, if the web lamination step is performed after the base sheet lamination step, the base sheet is not exposed on either the front or back of the resulting nonwoven fabric, which can prevent the texture and feel from changing significantly from those of a nonwoven fabric that does not include a base sheet.

(Adhesion process)
Next, the bonding process will be described.
The bonding process is a process in which fibers are bonded together using adhesive fibers contained in a fiber web (or a composite web in the case of a composite web; hereinafter, when the term "fiber web" is used in connection with the bonding process, it refers to either a fiber web or a composite web) to form bonded areas.

The bonding process may be, for example, a thermal bonding process. The thermal bonding process is a process in which the fiber web is heat-treated to melt or soften the component with the lowest melting point (thermal bonding component) among the resin components that make up the adhesive fibers, thereby forming bonded portions by bonding the fibers that make up the fiber web together.

The heat treatment may be, for example, a hot air processing treatment in which hot air is blown, a heat roll processing (e.g., a hot embossing roll processing), or a treatment using infrared rays. Hot air processing is preferred to make the resulting nonwoven fabric bulky. Hot air processing may be carried out using a device that blows hot air of a predetermined temperature onto the fiber web, such as a hot air penetration type heat treatment machine or a hot air blowing type heat treatment machine. In hot air processing using these devices, pressure is not easily applied in the thickness direction of the fiber web, so the resulting nonwoven fabric tends to be bulky.

When the bonding process is a hot air processing treatment, it is preferable to blow hot air multiple times. Furthermore, 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. Since the adhesive strength between cellulosic fibers and adhesive fibers is not higher than the adhesive strength between adhesive fibers, blowing hot air multiple times is effective in further increasing the adhesive strength between cellulosic fibers and adhesive fibers.

When the bonding process is a hot air processing treatment, the hot air speed may be, for example, 0.1 m/min to 3.0 m/min, particularly 0.2 m/min to 2.5 m/min, and more particularly 0.3 m/min to 2.0 m/min, in order to suppress fluffing and ensure bulkiness. If the hot air speed is too low, the fibers may not be bonded well to each other throughout the fiber web, and if it is too high, bulkiness may be impaired.

The heat treatment temperature may be the 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 above the melting point of that component. For example, if 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 hot air processing is performed. For example, if the component with the lowest melting point among the resin components constituting the adhesive fiber is ethylene-acrylic acid copolymer, hot air at a temperature of 90°C to 140°C may be blown when hot air processing is performed, particularly hot air at a temperature of 95°C to 130°C, and more particularly hot air at a temperature of 100°C to 120°C. Furthermore, from the viewpoint of suppressing fuzzing and the degree of freedom of the fibers, the heat treatment temperature is preferably at least 0°C and not more than 5°C higher than the melting point or softening point of the thermal adhesive component, more preferably at least 1°C and not more than 4°C higher, and even more preferably at least 2°C and not more than 3°C higher.

The bonding process may involve irradiation with an electron beam or ultrasonic welding. These bonding processes also allow the resin components that make up the adhesive fibers to bond the fibers together.

For example, if the fiber web after the bonding process has a breaking strength (tensile strength) in the MD direction of 1.0 N/5 cm or more, it is likely to produce a nonwoven fabric with sufficient adhesion and good fuzz suppression. The breaking strength (tensile strength) in the MD direction may be particularly 2.0 N/5 cm or more, more particularly 3.0 N/5 cm or more. The upper limit of the breaking strength (tensile strength) in the MD direction of the fiber web after the bonding process may be 100 N/5 cm, particularly 70 N/5 cm, and more particularly 40 N/5 cm. Furthermore, the fiber web after the bonding process may have a bending resistance of 100 g or less, as measured by a method conforming to JIS L 1096:2010 8.21.5 E method (handle-ometer method). In this case, it is likely to produce a nonwoven fabric with high bulk and high fiber flexibility. The bending resistance may be particularly 80 g or less, more particularly 60 g or less. The bending resistance of the fibrous web after the bonding step may have a lower limit of 5 g, particularly 10 g, more particularly 15 g. If the fibrous web after the bonding step has a thickness of 0.90 mm or more under a load of 294 Pa, for example, it becomes easier to obtain a nonwoven fabric with high bulk and a high degree of fiber freedom, and it also becomes easier to form highly entangled portions and low entangled portions well. The thickness under a load of 294 Pa may be particularly 1.1 mm or more, more particularly 1.3 mm or more. The upper limit of the thickness under a load of 294 Pa of the fibrous web after the bonding step may be 6.0 mm, particularly 5.0 mm, more particularly 4.0 mm. For example, if the ratio (T1/T2) of the thickness (T1) of the fiber web under a load of 294 Pa before the entanglement process described below to the thickness (T2) of the fiber web (nonwoven fabric) under a load of 294 Pa after the entanglement process is 1.2 or greater, a nonwoven fabric with high bulkiness and a high degree of fiber freedom is more likely to be obtained, and highly entangled portions and low entangled portions are more likely to be formed satisfactorily. T1/T2 may particularly be 1.3 or greater, more particularly 1.4 or greater. The upper limit of T1/T2 may be 5.0, particularly 4.0, and more particularly 3.0.

(cooling process)
The fiber web (composite web or laminate web; hereinafter, when referring to the cooling step, "fiber web" refers to the fiber web, composite web, or laminate web) subjected to the bonding step may be subjected to a cooling step before being subjected to the entangling step. More specifically, the fiber web or composite web may be subjected to a cooling step between the bonding step and the entangling step, between the bonding step and the base sheet lamination step, or between the bonding step and the web lamination step. Alternatively, if the fiber web or composite web is still hot after the lamination step and therefore the entire laminate web is hot, the laminate web may be subjected to a cooling step between the lamination step and the entangling step. The cooling step for the laminate web may be performed together with the cooling step for the fiber web or composite web, or the cooling step may be performed only after the laminate web has been formed.

If the fiber web after the bonding step is subjected to the subsequent entanglement step while some of the adhesive fibers are softened or melted, peeling may occur at the bonded portions, making the resulting nonwoven fabric more susceptible to fuzzing. Therefore, in the cooling step, the fiber web may be cooled until the adhesive components solidify. The cooling step may be natural cooling (allowing the fiber web to cool) or active cooling using a cooling device. The cooling method may be air cooling or water cooling. Natural cooling may be performed by running the fiber web on a belt or between rolls after the bonding step until it is sufficiently cooled.

(Confounding process)
Next, the intertwining step will be described.
The entanglement step is a step of carrying out a treatment to entangle the fibers in the fiber web after the bonding step. In this embodiment, after the bonding step, it is preferable to subject the fiber web to the entanglement step without winding it up on a roll. Similarly, when subjecting a composite web or a laminate web to the entanglement step, it is preferable to subject the composite web or laminate web to the entanglement step without winding it up on a roll. In other words, at any time after the bonding step or before the entanglement step, it is preferable to subject the fiber web, composite web, or laminate web to the entanglement step without winding it up on a roll. This makes it easier for the fibers to be entangled and allows the resulting nonwoven fabric to have a higher bulk.
Furthermore, when forming irregularities with the highly entangled portions as grooves and the less entangled portions as ridges, the fiber web after the bonding step can be subjected to the entanglement step without being wound up on a roll, which makes it easier to increase the bulk of the ridges, increase the degree of entanglement, and make the grooves denser. As a result, a nonwoven fabric can be obtained in which the ridges and grooves are clearly distinguishable from each other.

The entanglement process is, for example, a needle punch process or a high-pressure fluid flow (particularly a water flow) entanglement process. In a high-pressure fluid flow process, the high-pressure fluid is, for example, a high-pressure gas such as compressed air, or a high-pressure liquid such as high-pressure water. In the production of nonwoven fabrics, a water flow entanglement process using high-pressure water as the high-pressure fluid is often used, and in this embodiment, a water flow entanglement process is preferably used due to its ease of implementation. Below, we will explain the entanglement process when high-pressure water (hereinafter simply referred to as "water flow") is used as the high-pressure fluid.

In this embodiment, the entanglement step includes a partial entanglement step in which highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, are formed so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view. The partial entanglement step is carried out so that the width of the less entangled portions is 2 mm or more and 50 mm or less. The partial entanglement step may be carried out so that the width of the less entangled portions is 3 mm or more, particularly so that the width of the less entangled portions is 4 mm or more, and more particularly so that the width of the less entangled portions is greater than 5 mm. The partial entanglement step may be carried out so that the width of the less entangled portions is 25 mm or less, particularly so that the width of the less entangled portions is 20 mm or less, and more particularly so that the width of the less entangled portions is 10 mm or less. When the partial entanglement step is carried out as a hydroentanglement treatment, for example,
1) A nozzle in which minute orifices from which water streams are jetted are arranged at intervals of, for example, several millimeters, or 2) a nozzle in which orifice collection sections in which minute orifices from which water streams are jetted are arranged at intervals and orifice-less sections in which no orifices are drilled are arranged alternately can be used.

When nozzle 1) is used, the areas where the water stream from the orifice hits form streaks, forming highly entangled portions, while the areas not hit by the water stream form less entangled portions. The thickness of the highly entangled portions tends to be thinner than the less entangled portions. Depending on the type of fiber web used and the conditions of the bonding and entanglement processes, when nozzle 1) is used, it is possible to obtain a nonwoven fabric in which the less entangled portions rise up between the highly entangled portions to form ridges, and the highly entangled portions form grooves, as shown in Figure 1. Note that in Figure 1, the surface of the nonwoven fabric at the top of the figure (top surface) is the surface onto which the water stream was sprayed during the partial entanglement process.

In nozzle 1), the orifices may have a hole diameter of, for example, 0.05 mm or more and 0.5 mm or less, and the spacing between the orifices may be, for example, 2 mm or more and 20 mm or less, particularly 3 mm or more and 15 mm or less, more particularly 4 mm or more and 10 mm or less, and even more particularly 5 mm or more and 10 mm or less. If the spacing between the orifices is too narrow, the distance between the highly entangled portions will be narrow, i.e., the width of the less entangled portions will be narrow, and the effect of forming the less entangled portions (e.g., improved dirt collection ability when used as a wiper) may not be obtained. If the spacing between the orifices is too large, the number or proportion of the highly entangled portions in the obtained nonwoven fabric will be small, and the strength of the nonwoven fabric may be insufficient.
When using nozzle 1), the water pressure of the water stream may be, for example, 1 MPa to 10 MPa, in particular 1 MPa to 7 MPa.

Hydroentanglement can be carried out by placing a fiber web (or a composite web or a laminate web; hereinafter, the term "fiber web" in relation to hydroentanglement refers to a fiber web, a composite web, or a laminate web) on a support and spraying a columnar water stream onto it. As long as the nonwoven fabric surface is flat and free of irregularities, it is recommended that the support used has no openings with an opening area exceeding 0.2 ^mm2 per opening and no protrusions or patterns. For example, it is recommended that a plain weave support of 80 mesh or more and 100 mesh or less be used.

When nozzle 2) is used, the areas where the water jets from the orifices in the orifice assembly hit form band-shaped highly entangled regions, and the areas below the orifice-free regions form less entangled regions. The thickness of the highly entangled regions tends to be thinner than that of the less entangled regions. Depending on the type of fiber web used and the conditions of the bonding and entanglement processes, when nozzle 2) is used, it is possible to obtain a nonwoven fabric in which the less entangled regions rise up between the more entangled regions to form convex portions, as shown in Figure 2. Furthermore, compared to when nozzle 1) is used, wider highly entangled regions can be formed, and by selecting a support that supports the nonwoven fabric while the water jet is being sprayed, a pattern resembling an open hole pattern can be formed in the more entangled regions. In Figure 2, the surface of the nonwoven fabric at the top of the figure (top surface) is the surface onto which the water jet was sprayed during the partial entanglement process.

In nozzle 2), the orifices may have a diameter of, for example, 0.05 mm or more and 0.5 mm or less, and the spacing between the orifices in the orifice assembly may be 0.3 mm or more and 1.5 mm or less. The width of the orifice-free section between the orifice assembly sections may be, for example, 2 mm or more and 50 mm or less, particularly 3 mm or more and 25 mm or less, more particularly 4 mm or more and 20 mm or less, even more particularly 4 mm or more and 10 mm or less, and even more particularly 5 mm or more and 10 mm or less. The width of the orifice assembly section may be, for example, 2 mm or more and 50 mm or less, particularly 3 mm or more and 25 mm or less, more particularly 4 mm or more and 20 mm or less, and even more particularly 4 mm or more and 10 mm or less. Furthermore, when nozzle 2) is used, the water pressure of the water flow may be, for example, 1 MPa to 10 MPa, particularly 1 MPa to 7 MPa.

Whether nozzle 1) or 2) is used, the fiber web is continuously passed under the nozzle to perform the hydroentanglement treatment, resulting in a nonwoven fabric with highly entangled and less entangled portions arranged alternately in the CD direction in a planar view. Furthermore, whether nozzle 1) or 2) is used, in areas where the water stream is not sprayed, entanglement of the fibers does not substantially progress, resulting in the formation of less entangled portions. In such less entangled portions, the fibers are integrated together by the adhesion of the adhesive fibers.

Whether nozzle 1) or 2) is used, the nozzle may be designed to spray water over the entire surface, with the orifice in the section corresponding to the less entangled portion plugged.

Whether nozzle 1) or 2) is used, the hydroentanglement treatment in the partial entanglement step is preferably carried out by placing the fiber web on a support and spraying a columnar water stream only once onto one side of the fiber web. This is because in the partial entanglement step, it is preferable to carry out the hydroentanglement treatment so that highly entangled and low entangled portions are formed and the boundary between them is clearly defined. If the water stream is sprayed multiple times onto one side, or if the water stream is sprayed onto both sides, it becomes difficult to form highly entangled and low entangled portions.

The support may be one that does not have any openings with an area of each opening exceeding 0.2 ^mm2 , and that does not have any protrusions or patterns formed thereon. Such a support may be, for example, a plain weave support of 80 mesh or more and 100 mesh or less. When such a support is used and a water flow is sprayed from nozzle 2), the highly entangled portions become relatively flat and have no patterns or openings.

Alternatively, the support may be a plate-shaped or roll-shaped support, and particularly a roll-shaped support. When the support is in roll form, the fiber web curves, resulting in a lower fiber density in the thickness direction of the fiber web (or typically in the outward direction of a curved web). When a columnar water stream is sprayed from the outside, entanglement by the columnar water stream progresses relatively easily. In the manufacturing method of this embodiment, the fiber web including the bonded portions subjected to the bonding process is subjected to the entanglement process, so entanglement of the fibers progresses relatively less. Therefore, in the entanglement process, it is preferable to perform the hydroentanglement treatment in a state in which entanglement progresses more easily.

When using nozzle 2), a pattern can be formed in the highly entangled portion by appropriately selecting the support. The support used to form the pattern (hereinafter referred to as the "pattern-forming support") may be a woven fabric, a punched plate-like member, or a spiral net made of natural resin, synthetic resin, or metal. The pattern-forming support may also have a regular pattern formed by regularly arranging one or more selected from convex portions, concave portions, and openings. Using such a pattern-forming support, a regular pattern can be formed by a collection of multiple regions with a lower density than other portions (hereinafter referred to as "low-density regions"). The low-density regions may be formed as open holes.

Specifically, the pattern formation support may be, for example, a plain weave, herringbone weave, twill weave, or satin weave woven from monofilaments with a fiber diameter of approximately 0.1 mm to 1.2 mm at a warp density of 10 to 30 threads/inch and a weft density of 10 to 30 threads/inch. Supports made from fabrics with relatively thick filaments have convex portions at the intersections of the warp and weft threads, making it possible to form low-density regions. When using such fabrics, the area per low-density region is determined by the thickness of the threads that make up the fabric, and the spacing and pitch of the low-density regions are determined by the warp and weft densities of the fabric.

In plain weave fabrics, where the warp and weft threads are each made of a single monofilament, the highest points of intersection of the warp and weft threads form convex portions, which are arranged in a staggered pattern. Therefore, by using such plain weave fabric, it is possible to form low-density regions arranged in a staggered pattern corresponding to these portions.

Alternatively, the pattern formation support may have convex portions and/or concave portions, for example, truncated cone-shaped, conical, truncated pyramidal, or pyramidal protrusions, or concave portions formed by subjecting the surface of a metal plate to cutting or the like, and the portions other than the convex portions and/or concave portions may be a plate-like member (for example, a metal plate) in which, for example, small openings are formed to ensure water permeability.
Alternatively, the patterned support may be a spiral net.

(Full surface entangling process)
In the manufacturing method of this embodiment, the entanglement step may further include a full-scale entanglement step in which fibers are entangled throughout the entire fiber web (or composite web or laminate web; hereinafter, when the term "fiber web" is used in connection with the full-scale entanglement step, it refers to the fiber web, composite web, or laminate web). The full-scale entanglement step may be performed before the partial entanglement step. The full-scale entanglement step is performed when the entanglement of fibers in the partial entanglement step alone is not sufficient to provide the strength of the nonwoven fabric or to suppress fuzzing and shedding. By performing the full-scale entanglement step, the bulkiness of the resulting nonwoven fabric, particularly in the less entangled portions, is slightly reduced, but the strength of the entire nonwoven fabric can be increased and fuzzing is further suppressed.

The full-surface entanglement process may be a hydroentanglement process. The support used in the hydroentanglement process carried out as the full-surface entanglement process is the support described as being used in the partial entanglement process when no pattern is formed in the highly entangled portions. When such a support is used, the surface of the fiber web after the entanglement process will be flat and free of irregularities.

The hydroentanglement treatment can be carried out, for example, by spraying water at a pressure of 1 MPa to 15 MPa from a nozzle having orifices with a hole diameter of 0.05 mm to 0.5 mm spaced at intervals of 0.3 mm to 1.5 mm onto each of the front and back surfaces of the fiber web, one to five times. The water pressure is preferably 1 MPa to 10 MPa, more preferably 1 MPa to 7 MPa.

The full-surface entanglement process may be carried out so that the water pressure of the water flow is lower than that of the partial entanglement process. If the water pressure in the full-surface entanglement process is the same as or higher than that in the partial entanglement process, the bulkiness of the nonwoven fabric may decrease. In other words, the full-surface entanglement process is preferably carried out using a water flow with as low a water pressure as possible, without excessively reducing the bulk of the nonwoven fabric, and to the extent necessary to integrate the fibers. In contrast, in the partial entanglement process, a water flow with a higher water pressure than that used in the full-surface entanglement process may be used to ensure the strength of the nonwoven fabric. In the partial entanglement process, because the area hit by the water flow is limited, even if the water pressure is increased, the loss of bulk of the entire nonwoven fabric is suppressed to some extent. Note that if the water flow in the full-surface entanglement process is sprayed multiple times, the water pressure of the water flow each time may be lower than that of the partial entanglement process.

The hydroentanglement treatment in the full-surface entanglement step may be carried out by spraying a water stream onto only one side of the fibrous web. In this case, the partial entanglement step may be carried out by spraying a water stream onto the side opposite to the side sprayed with the water stream in the full-surface entanglement step. More specifically, both the full-surface entanglement step and the partial entanglement step may be carried out by hydroentanglement treatment in which a water stream is sprayed onto only one side of the fibrous web, composite web, or laminate web, and the side sprayed with the water stream in the partial entanglement step may be the side opposite to the side sprayed with the water stream in the full-surface entanglement step. In the partial entanglement step, spraying a water stream onto the side opposite to the side sprayed with the water stream in the full-surface entanglement step may sometimes allow for a higher degree of freedom of the fibers. Therefore, when the nonwoven fabric is used as a wiper, using the side sprayed with the water stream in the partial entanglement step as the wiping surface can improve dirt collection performance. Furthermore, when forming irregularities with grooves in the highly entangled areas and ridges in the less entangled areas, the ridges and grooves can be clearly formed by spraying the water onto different surfaces in the full entanglement process and the partial entanglement process.

When the bonding process is a hot air processing process, it is preferable that the hydroentangling process first spray a columnar water stream onto the surface onto which hot air was blown in the hot air processing process (hereinafter referred to as the "hot air blown surface"), and then spray a columnar water stream onto the opposite surface. Therefore, when the entangling process includes a full-area entangling process, it is preferable to first spray a columnar water stream onto the hot air blown surface, and then spray a water stream partially onto the opposite surface using nozzle 1) or 2). Alternatively, a columnar water stream may be sprayed onto the entire hot air blown surface, and then a columnar water stream may be sprayed onto the entire opposite surface, after which hydroentangling may be performed using nozzle 1) or 2). In this case, the water stream from nozzle 1) or 2) may be sprayed onto the hot air blown surface, or onto the opposite surface.

The surface onto which the hot air is blown tends to have a lower fiber density than the opposite surface (generally the surface in contact with the support during the hot air processing treatment), making entanglement by the columnar water stream relatively easy to proceed. The strength of the nonwoven fabric and the degree of fuzz suppression achieved by the water stream entanglement treatment are likely to depend on the degree of entanglement in the initial entanglement treatment. For this reason, it is preferable to spray the columnar water stream from the side of the fiber web where the fiber density is relatively low and where entanglement is relatively easy to proceed.

For example, if fiber web A and fiber web B are prepared separately, fiber web A is subjected to a bonding process, fiber web B is then laminated onto it, and the laminated web is subjected to hydroentanglement treatment in the entanglement process, it is preferable to spray the columnar water stream first from the hot air blowing surface side of fiber web A. Therefore, for example, if fiber web B is laminated on the hot air blowing surface of fiber web A, it is preferable to spray the columnar water stream first from the fiber web B side. Furthermore, if another nonwoven fabric is laminated on the hot air blowing surface of the fiber web, it is preferable to spray the columnar water stream first from the other nonwoven fabric side.

(drying process)
In the manufacturing method of this embodiment, after the entangling step, the fiber web (or composite web or laminate web) may be subjected to a drying step. In particular, when the entangling step includes a hydroentangling treatment, it is preferable to carry out the drying step. The drying step can be carried out by a hot air processing treatment in which hot air is blown, or the like. The temperature of the drying treatment is preferably lower than the softening or melting temperature of the adhesive component (thermal adhesive component) of the adhesive fiber. 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 less lower. In the manufacturing method of this embodiment, after the entangling step, the fiber web may be subjected to a second bonding step as described below, or it is not necessary to perform the second bonding step. If a second bonding step is performed, the drying step may be omitted.

(Gluing process after entangling)
In the manufacturing method of this embodiment, the fiber web (or composite web or laminate web; hereinafter, when the term "fiber web" is used in connection with the post-entangling bonding step, it refers to the fiber web, composite web, or laminate web) after the entangling step may be further subjected to a bonding step. This bonding step is referred to as the "post-entangling bonding step" to distinguish it from the bonding step carried out before the entangling step. The conditions used in the post-entangling bonding step are the same as those described in connection with the bonding step.

In the entanglement step, the bonded portions may be destroyed due to the impact of the water jets, etc. If the destruction is significant, the improvement in strength of the nonwoven fabric and the effect of suppressing fuzzing due to the adhesion of the fibers may not be achieved. The post-entanglement bonding step may be performed to compensate for the decrease in strength due to such destruction. Therefore, the conditions for the post-entanglement bonding step are appropriately selected depending on the degree of destruction of the bonded portions in the entanglement step and the physical properties of the nonwoven fabric to be finally obtained. For example, the post-entanglement bonding step may be performed at a lower or higher temperature than the temperature in the bonding step. Alternatively, the post-entanglement bonding step may be performed under the same conditions as the bonding step.
Generally, nonwoven fabrics produced by a manufacturing method including a post-entanglement bonding step are less likely to fluff or fall off compared to nonwoven fabrics produced by a manufacturing method that does not include this step. Furthermore, although the bulk of the fiber web after the entanglement treatment is reduced, the bulk of the fiber web can be restored by subsequently carrying out a bonding step, particularly a hot air treatment. Therefore, a manufacturing method including a post-entanglement bonding step can sometimes produce a bulkier nonwoven fabric. In particular, when the entanglement step includes a hydroentanglement treatment, evaporation of water during the post-entanglement bonding treatment eliminates "sagging" due to the weight of the water, and it is thought that the bulk of the fiber web can be more easily restored.

[Embodiment 2]
(Manufacturing method including lamination process)
The manufacturing method of the second embodiment of the present disclosure includes a lamination step in which fiber webs A and B are prepared separately, only fiber web A is subjected to a bonding step, and fiber web B is laminated on fiber web A after the bonding step to obtain a laminated web. This manufacturing method facilitates incorporating a variety of fibers into the entire nonwoven fabric. In the manufacturing method of the second embodiment, the laminated web is subjected to an entanglement step. The fiber web to be subjected to the entanglement step has a portion (fiber web B) that does not have any bonded portions formed therein, and therefore, when a water stream is sprayed onto the portion, entanglement tends to proceed more rapidly. Therefore, sufficient entanglement is likely to be achieved even if the water pressure of the water stream used in the entanglement step is reduced or the proportion of cellulosic fibers is reduced. Furthermore, in the manufacturing method of the second embodiment, when a pattern is formed in a highly entangled portion, a clear pattern is likely to be formed. On the other hand, in the manufacturing method of the second embodiment, the number of bonded portions in the fiber web after the entanglement step is reduced compared to when the entire fiber web is subjected to the bonding step and then the entanglement step is performed. Therefore, in the manufacturing method of the second embodiment, it is preferable to perform a bonding step after entanglement.

Alternatively, the manufacturing method of embodiment 2 of the present disclosure may include a base sheet laminating step in which a base sheet is laminated after subjecting fiber web A to the bonding step, or may include a web laminating step in which fiber web B is laminated after the base sheet laminating step. Nonwoven fabrics laminated with a base sheet generally tend to have higher mechanical properties (particularly stress at 10% elongation) than nonwoven fabrics that do not include a base sheet. Therefore, by using a base sheet, it is possible to obtain a nonwoven fabric that is less likely to fluff or fall off and that meets the mechanical properties required for a certain application, even if a post-entanglement bonding step is not performed.

When a base sheet is laminated, the entanglement process may be carried out using a higher water pressure than when a base sheet is not laminated, to prevent delamination between the base sheet and the fiber web. When the base sheet is a long-fiber nonwoven fabric, in particular, delamination between the base sheet and the fiber web is likely to occur, so a higher water pressure may be used.

In the manufacturing method of embodiment 2, the conditions for the bonding process, entangling process, post-entangling bonding process, and drying process are the same as those described in or in connection with the manufacturing method of embodiment 1, and therefore will not be described here. However, the conditions for these processes are adjusted appropriately depending on the types and proportions of fibers contained in fibrous webs A and B, as well as their basis weights.

[Embodiment 3]
(Nonwoven fabric obtained by the manufacturing method of the present disclosure)
Next, a nonwoven fabric obtained by the manufacturing method of the first or second embodiment described above will be described as a third embodiment of the present disclosure.

The nonwoven fabric of this embodiment is produced by a method including a bonding process, an entanglement process including a partial entanglement process, and optionally a post-entanglement bonding process, and therefore includes bonded areas where fibers are bonded to each other, as well as areas where fibers are relatively tightly entangled. Particularly in the partial entanglement process, in areas where the water stream is sprayed, the fibers are more tightly entangled, forming highly entangled areas. In the partial entanglement process, in areas where the water stream is not sprayed, low-entangled areas are formed, where the degree of entanglement between fibers is lower than in the high-entangled areas.

The highly entangled portions and the less entangled portions are alternately arranged in one direction of the nonwoven fabric, and in nonwoven fabrics produced using nozzle 1) or 2) above, they are alternately arranged in the CD direction of the nonwoven fabric. Furthermore, the thickness of the highly entangled portions tends to be thinner than that of the less entangled portions, which can result in the formation of irregularities with the highly entangled portions acting as grooves and the less entangled portions acting as ridges. The formation of irregularities is particularly likely when using a manufacturing method including a lamination process, as described in embodiment 2 above.

The ease with which irregularities form also varies depending on the blend ratio of cellulosic fibers to adhesive fibers. For example, the higher the proportion of cellulosic fibers, the fewer bonded points formed in the bonding process. Therefore, to ensure the strength of the nonwoven fabric, it is necessary to perform a full-scale entanglement process before the partial entanglement process. However, the full-scale entanglement process reduces the overall bulk of the nonwoven fabric, making it difficult for irregularities to form even when the partial entanglement process is performed. On the other hand, the higher the proportion of adhesive fibers, the greater the number of bonded points formed in the bonding process, and the smaller the proportion of cellulosic fibers that contribute to fiber entanglement. Therefore, even when the partial entanglement process is performed, there is little difference in the degree of entanglement between the highly entangled and less entangled areas, making it difficult for irregularities to form.

Highly entangled portions are areas where fibers are more tightly entangled with each other, contributing to a certain degree of increased strength of the nonwoven fabric. In the lowly entangled portions, the degree of entanglement between fibers is low, resulting in a relatively high degree of fiber freedom, contributing to a certain degree of increased bulk of the nonwoven fabric. Furthermore, in the lowly entangled portions, although the degree of fiber freedom is relatively high, bonding points where fibers are bonded together are formed, making pilling less likely to occur. Furthermore, in the nonwoven fabric of this embodiment, the lowly entangled portions may have a width of 2 mm to 50 mm. By having lowly entangled portions of such widths, the degree of fiber freedom of the nonwoven fabric as a whole can be relatively high. The width of the lowly entangled portions may particularly be 3 mm to 25 mm, more particularly 4 mm to 20 mm, even more particularly 4 mm to 10 mm, and even more particularly 5 mm to 10 mm.

Therefore, when the nonwoven fabric of this embodiment is used, for example, as a wiper, the highly entangled portions ensure the strength of the wiper, while the less entangled portions wipe away and collect dirt. Furthermore, when the nonwoven fabric of this embodiment is used as a wiper, even when it is rubbed against a person's body or an object to wipe away dirt, pilling is unlikely to occur.

The widths of the highly entangled and less entangled portions are determined by the type of nozzle used for partial entanglement and the spacing between the orifices in the nozzle (in the case of Nozzle 1) or the width and spacing of the orifice assembly (in the case of Nozzle 2). When Nozzle 1) is used, the highly entangled portions are substantially linear, and less entangled portions are formed with a width equivalent to the spacing between the orifices. When Nozzle 2) is used, highly entangled portions are formed with a width equivalent to the width of the orifice assembly, and less entangled portions are formed with a width equivalent to the spacing between the orifice assembly (the distance from one end of an orifice assembly to the end of an adjacent orifice assembly).

When nozzle 2) is used, as described above, low-density regions can be regularly formed in the highly entangled portions to form a pattern. A nonwoven fabric having a pattern formed in the highly entangled portions exhibits a design effect. Furthermore, by forming low-density regions in the highly entangled portions, when the obtained nonwoven fabric is used as a wiper, the low-density regions can improve the dirt collection ability.
Each low-density region may have an area of, for example, 0.03 mm ² to 20 mm ² , particularly 0.1 mm ² to 10 mm ² , and more particularly 0.7 mm ² to 5.0 mm ^2. If the low-density region is too small, it may not be sufficiently recognized, and the design effect may not be fully exerted. If the low-density region is too large, the nonwoven fabric is prone to deformation or damage such as stretching, twisting, and tearing, and handleability is reduced. Furthermore, if the low-density region is too large, it may be difficult to recognize as a low-density region, and the design effect may not be fully exerted.

The low-density regions may be open pores where no fibers are present, or may not be open pores. Alternatively, a single nonwoven fabric may contain both open pores and non-open pore low-density regions to form a pattern.

The nonwoven fabric of this embodiment may have a basis weight of, for example, 10 g/m ² to 150 g/m ² , particularly 15 g/m ² to 120 g/m ² , more particularly 30 g/m ² to 100 g/m ² , and even more particularly 40 g/m ² to 80 g/m ² .

The nonwoven fabric of this embodiment may have, as a whole, a fiber density in a dry state of, for example, 0.0100 g/cm ³ to 0.100 g/cm ³ , preferably 0.0125 g/cm ³ to 0.0600 g/cm ³ , and more preferably 0.0180 g/cm ³ to 0.0500 g/cm ^3. The fiber density of the entire nonwoven fabric can be determined from the basis weight and thickness (thickness measured under a load of 1.96 kPa).

In the nonwoven fabric of this embodiment, it is preferable that adhesion/peeling marks, where adhesion points formed by the adhesive fiber have been eliminated, are formed in the adhesive fibers. Adhesion/peeling marks can be formed mainly during the entanglement process that follows the bonding process. In adhesion/peeling marks, the adhesive component (for example, the sheath component in the case of a core-sheath composite fiber) is present in a thin layer compared to the fiber surface of a typical adhesive fiber. These adhesion/peeling marks make the fibers more flexible, which can improve the flexibility of the nonwoven fabric, so it is preferable that adhesion/peeling marks are included appropriately. Adhesion/peeling marks can be confirmed by observing the surface or cross section of the nonwoven fabric using an electron microscope.

The nonwoven fabric of this embodiment, as described in the examples below, may have a bond intersection index A of ¹ to 63/ ^mm2 . The upper limit of the bond intersection index A may particularly be 60/ ^mm2 , more particularly 55/ ^mm2 , and even more particularly 50/ ^mm2 . The lower limit of the bond intersection index A may particularly be 3/mm2, more particularly 5/ ^mm2 , even more particularly 10/ ^mm2 , and even more particularly 25/ ^mm2 . When the bond intersection index A of the nonwoven fabric is within the above-mentioned range, fluffing of the nonwoven fabric is suppressed and an appropriate degree of fiber freedom is ensured. The bond intersection index of the nonwoven fabric may differ between the highly entangled portions and the ^low entangled portions, and in such cases, the bond intersection index of the low entangled portions is taken as the bond intersection index of the nonwoven fabric. However, it is preferable that the adhesive node index A is within the above range in both the highly entangled portions and the less entangled portions.

In the nonwoven fabric of this embodiment, when the nonwoven fabric described in the following examples is divided into three equal parts in the thickness direction, the angle of the fiber bonding intersections at either or both of the upper and lower parts of the nonwoven fabric is preferably 35 degrees to 90 degrees, more preferably 35 degrees to 70 degrees, and even more preferably 40 degrees to 60 degrees.
The nonwoven fabric of this embodiment tends to be highly bulky when the angle of the bonded fiber intersections in either or both of the upper and lower portions of the nonwoven fabric, i.e., in the portions near one or both surfaces of the nonwoven fabric, is within the above-mentioned range. The angle of the bonded fiber intersections may differ between the highly entangled portions and the low entangled portions. In such cases, the angle of the bonded fiber intersections in the low entangled portions is defined as the angle of the bonded fiber intersections of the nonwoven fabric. However, it is preferable that the angle of the bonded fiber intersections in both the highly entangled portions and the low entangled portions be within the above-mentioned range.

When the nonwoven fabric of this embodiment has grooves and ridges formed by the highly entangled portions and the less entangled portions, respectively, and has an uneven surface on one side, the angle of the bonded fiber intersections on the uneven surface may be within the above range. When the angle of the bonded fiber intersections on the uneven surface is within the above range, the degree of freedom of the fibers on that surface is relatively high. Therefore, when the uneven surface is used as the wiping surface of a wiper, for example, this, combined with the low fiber density in the convex portions (ridges), will result in good dirt collection properties.

The nonwoven fabric of this embodiment may be a nonwoven fabric in which the amount of fluff shedding on at least one side is 1.5 mg or more and 20 mg or less, as described in the Examples below. The nonwoven fabric of this embodiment may be a nonwoven fabric in which the amount of fluff shedding on both sides is 1.5 mg or more and 20 mg or less. When the amount of fluff shedding on at least one side is within the above range, that side has a high degree of fiber freedom and is less likely to fluff. Therefore, when the nonwoven fabric is used as a wiper, when that side is used as the wiping surface, it has good dirt collection properties and fluffing during wiping is suppressed, giving the user a clean impression. The amount of fluff shedding on at least one side may particularly be 2.0 mg or more and 15 mg or less.

A nonwoven fabric surface with a shedding amount within the above range may be a surface in which the highly entangled portions and the less entangled portions form grooves and ridges, respectively (i.e., an uneven surface). If the shedding amount from the uneven surface is within the above range, when the uneven surface is used as the wiping surface of a wiper, for example, it is less likely to fluff, and the unevenness can effectively capture dirt.

With regard to the breaking strength (tensile strength) of the nonwoven fabric of this embodiment, as explained in the examples below, the breaking strength (tensile strength) in the MD direction may be, for example, 10 N to 200 N, and particularly 30 N to 150 N. The breaking strength (tensile strength) in the CD direction may be, for example, 1 N to 30 N, and particularly 2 N to 20 N. When the strength of the nonwoven fabric is within the above-mentioned range, the handleability of the nonwoven fabric of this embodiment tends to be further improved.

The nonwoven fabric of this embodiment is preferably used as a wiper because it includes bonded areas formed by bonding fibers together, ensures a certain degree of fiber freedom, and has bulky, low-entanglement areas. When used as a wiper, the wiper may be a wet-type wiper impregnated with cleaning liquid. Because the nonwoven fabric of this embodiment contains cellulosic fibers, it is easy to impregnate with cleaning liquid.

Alternatively, the nonwoven fabric of this embodiment can also be used as various sheets such as top sheets, second sheets, and back sheets of absorbent articles, filters, sanitary masks, gauze, face masks impregnated with cosmetics, patches, packaging materials, mats, cushioning materials, tablecloths, carpet backing materials, wallpaper, etc.

[Embodiment 4]
A method for producing a nonwoven fabric according to a fourth embodiment of the present disclosure includes:
A method for producing a nonwoven fabric containing adhesive fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
A method for manufacturing nonwoven fabric.

In the manufacturing method of embodiment 4, the adhesive fibers used, and the conditions for the bonding process, entanglement process, post-entanglement bonding process, and drying process can be appropriately applied from the conditions described in the manufacturing method of embodiment 1.

[Embodiment 5]
A method for producing a nonwoven fabric according to a fifth embodiment of the present disclosure includes:
A method for producing a nonwoven fabric comprising a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step;
A method for manufacturing nonwoven fabric.

In the manufacturing method of embodiment 5, the adhesive fibers, base sheet, bonding process, entanglement process, post-entanglement bonding process, and drying process conditions, etc., used can be the same as those described in the manufacturing method of embodiment 1, as appropriate.

[Embodiment 6]
The nonwoven fabric obtained by the manufacturing method of embodiment 4 will be described as the nonwoven fabric of embodiment 6 of the present disclosure. That is, the nonwoven fabric of embodiment 6 of the present disclosure is
A nonwoven fabric comprising adhesive fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as determined by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In the nonwoven fabric of embodiment 6, the conditions described in embodiment 1 or embodiment 3 can be applied as appropriate to conditions such as adhesive fibers, bonded locations, entangled locations, highly entangled sections, less entangled sections, the width of the less entangled sections, and the amount of fluff shedding from the nonwoven fabric.

[Embodiment 7]
The nonwoven fabric obtained by the manufacturing method of embodiment 5 will be described as the nonwoven fabric of embodiment 7 of the present disclosure. That is, the nonwoven fabric of embodiment 7 of the present disclosure is
A nonwoven fabric comprising a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The nonwoven fabric has a fluff shedding amount of 1.5 mg or more and 20 mg or less on at least one surface of the nonwoven fabric, as determined by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

In the nonwoven fabric of embodiment 7, the conditions described in embodiment 1 or embodiment 3 can be applied as appropriate to the adhesive fibers, base sheet, bonded areas, entangled areas, highly entangled areas, less entangled areas, the width of the less entangled areas, and the amount of fluff shedding from the nonwoven fabric.

The nonwoven fabric of embodiment 6 or the nonwoven fabric of embodiment 7 includes bonded areas formed by bonding fibers together, ensures a certain degree of fiber freedom, and has bulky, low-entanglement areas, making it suitable for use as a wiper. When used as a wiper, the wiper may be a wet wiper impregnated with a cleaning liquid.

The fibers used to produce the nonwoven fabrics of the Examples and Comparative Examples are shown below.
Fiber 1 (adhesive fiber): An eccentric core-sheath composite fiber having a polyethylene terephthalate core and a high-density polyethylene (melting point: approximately 133°C) sheath, a fineness of 2.6 dtex, a fiber length of 51 mm, and an eccentricity of 25% and three-dimensional crimp (NBF(SH)V (product name) manufactured by Daiwabo Polytec Co., Ltd.).
Fiber 2 (cellulosic fiber): Viscose rayon fiber having a fineness of 1.7 dtex and a fiber length of 40 mm (Corona CD (trade name) manufactured by Daiwabo Rayon Co., Ltd.).

<Production of nonwoven fabric of Example 1>
Fiber 1 and fiber 2 were mixed in a mixing ratio of 7:3 (mass ratio) and a parallel carding machine was used to produce fiber web A. The basis weight (target basis weight) of fiber web A was 30 g/ ^m2 .
[Adhesion process/cooling process]
The fiber web A was heated for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine, thereby thermally bonding (adhesion treatment) the fibers together via the sheath component of fiber 1. After the thermal bonding (adhesion treatment), the fiber web was subjected to a cooling step in an atmosphere at room temperature of 20°C by natural cooling.
[Web Lamination Process]
Fiber 1 and fiber 2 were mixed in a mixing ratio of 7:3 (mass ratio), and a parallel carding machine was used to produce fiber web B having a target basis weight of 30 g/ ^m2 . This was then laminated on cooled fiber web A to obtain a laminated web.

[Full-scale entangling process]
The above-mentioned laminated web was placed on a plain weave net with a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90 meshes. While the laminated web was advanced at a speed of 4 m/min, a water supply device was used to spray a columnar water stream at a water pressure of 1.5 MPa onto the surface of fiber web B of the laminated web. The nozzle of the water supply device had orifices with a hole diameter of 0.12 mm spaced 0.6 mm apart. The distance between the surface of the laminated web and the orifices was 15 mm. After the bonding process, fiber web A and the laminated web were subjected to a full-surface entanglement process without being wound up on a roll.

[Partial confounding process]
After the full-surface entanglement process, the laminated web was placed on a 25-mesh plain-weave support (warp and weft densities of both 25 threads/inch) made of monofilaments with a wire diameter of 0.7 mm, and a columnar water stream was sprayed onto the surface of the fibrous web A of the laminated web. This entanglement process resulted in the formation of grooves, or highly entangled regions, extending along the MD direction of the nonwoven fabric where the water stream was sprayed. Areas where the water stream was not sprayed became less entangled regions, forming ridges. The highly entangled and less entangled regions were alternately arranged in the CD direction of the nonwoven fabric. The nozzle of the water supply machine used in the full-surface entanglement process was the same as that used in the full-surface entanglement process, but some of the multiple orifices were blocked to prevent the water stream from coming out, so that the widths of the formed ridges and grooves were each 6 mm. The laminated web was advanced at a speed of 4 m/min, the water pressure of the columnar water stream was 3.0 MPa, and the distance between the surface of the laminated web and the orifice was 15 mm. A pattern in which openings were arranged in a staggered pattern was formed in the grooves. The area of each aperture was 1.05 mm ² , and the distance between the centers of the nearest apertures was 1.5 mm.

[Adhesion process after entangling]
The laminated web after the entangling step was heated for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine to dry the laminated web and thermally bond the fibers together via the sheath component of fiber 1, thereby obtaining a nonwoven fabric of Example 1.

<Production of nonwoven fabric of Example 2>
A nonwoven fabric of Example 2 was obtained in the same manner as in Example 1, except that the partial entanglement step was changed as follows.
[Partial confounding process]
The laminated web was placed on the plain weave net used in the full-surface entanglement process, and columnar water streams were sprayed onto the surface of the fiber web A of the laminated web. This entanglement process resulted in linear grooves of highly entangled portions extending along the MD direction of the nonwoven fabric at the locations where the water streams were sprayed. Locations where the water streams were not sprayed became less entangled portions, forming ridges. The nozzle of the water supply machine used was a nozzle with orifices having a hole diameter of 0.2 mm spaced 7 mm apart. The laminated web was advanced at a speed of 4 m/min, the water pressure of the columnar water streams was 3.0 MPa, and the distance between the surface of the laminated web and the orifices was 15 mm.

<Production of nonwoven fabric of Example 3>
The nonwoven fabric of Example 3 was obtained in the same manner as the nonwoven fabric of Example 1, except that the mixing ratio of fiber 1 to fiber 2 in fiber webs A and B was 6:4 (mass ratio).

<Production of nonwoven fabric of Example 4>
The nonwoven fabric of Example 4 was obtained in the same manner as the nonwoven fabric of Example 2, except that the mixing ratio of fiber 1 to fiber 2 in fiber webs A and B was 6:4 (mass ratio).

<Production of nonwoven fabric of Example 5>
[Adhesion process/cooling process]
Fiber 1 and fiber 2 were mixed in a mixing ratio of 7:3 (mass ratio) and a fiber web was produced using a parallel carding machine. The target weight of the fiber web was 60 g/ ^m2 .
This fiber web was heated for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine, thereby thermally bonding (adhesion treatment) the fibers together via the sheath component of fiber 1. After thermal bonding (adhesion treatment), the fiber web was subjected to a cooling step in an atmosphere of room temperature (20°C) by natural cooling.

[Full-scale entangling process]
The above-mentioned fiber web was placed on a plain weave net with a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90. While the fiber web was traveling at a speed of 4 m/min, a water supply device was used to spray a columnar water stream at a water pressure of 1.5 MPa onto the surface of the fiber web on the side where the hot air had been blown. The nozzle of the water supply device had orifices with a hole diameter of 0.12 mm spaced 0.6 mm apart. The distance between the surface of the fiber web and the orifices was 15 mm. After the bonding process, the fiber web was subjected to the entanglement process without being wound up on a roll.

[Partial confounding process]
After the full-surface entanglement process, the nonwoven fabric was placed on a 25-mesh plain-weave support (warp and weft densities of both 25 threads/inch) made of monofilaments with a wire diameter of 0.7 mm, and a columnar water stream was sprayed onto the surface opposite to the surface onto which the water stream was sprayed in the full-surface entanglement process. As a result of this entanglement process, highly entangled portions extending along the MD direction of the nonwoven fabric were formed as grooves at the locations where the water stream was sprayed. Locations where the water stream was not sprayed became less entangled portions, forming ridges. The highly entangled portions and less entangled portions were alternately arranged in the CD direction of the nonwoven fabric. The nozzle of the water supply machine used in the full-surface entanglement process was the same as that used in the full-surface entanglement process, but some of the multiple orifices were blocked to prevent the water stream from coming out, so that the widths of the formed ridges and grooves were each 6 mm. The fiber web was advanced at a speed of 4 m/min, the water pressure of the columnar water stream was 3.0 MPa, and the distance between the surface of the fiber web and the orifice was 15 mm. A staggered pattern of apertures was formed in the grooves, with each aperture having an area of 1.05 mm ² and a distance of 1.5 mm between the centers of the closest apertures.

[Drying process]
The fiber web after the entangling step was dried by heating for about 5 seconds using a hot air penetration type heat treatment machine by blowing hot air at 80° C., to obtain a nonwoven fabric of Example 5.

<Production of nonwoven fabric of Example 6>
A nonwoven fabric of Example 6 was obtained in the same manner as in Example 5, except that the partial entanglement step was changed as follows.
[Partial confounding process]
The nonwoven fabric was placed on a plain weave net used in the full-surface entanglement process, and a columnar water stream was sprayed onto the surface opposite to the surface onto which the water stream was sprayed in the full-surface entanglement process. This entanglement process resulted in linear grooves of highly entangled portions extending along the MD direction of the nonwoven fabric at the locations where the water stream was sprayed. Locations where the water stream was not sprayed became less entangled portions, forming ridges. The nozzle of the water supply machine used was a nozzle with orifices having a hole diameter of 0.2 mm and spaced 7 mm apart. The speed at which the fibrous web fabric was advanced was 4 m/min, the water pressure of the columnar water stream was 3.0 MPa, and the distance between the surface of the fibrous web and the orifice was 15 mm.

<Production of nonwoven fabric of Example 7>
The nonwoven fabric of Example 7 was obtained in the same manner as in producing the nonwoven fabric of Example 5, except that a post-entanglement bonding step was carried out instead of the drying step after the entanglement step in Example 5. The post-entanglement bonding step was carried out by heating for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine. In the post-entanglement bonding step, the fibers were thermally bonded (bonded) to each other by the sheath component of fiber 1.

<Production of nonwoven fabric of Example 8>
The nonwoven fabric of Example 8 was obtained in the same manner as in producing the nonwoven fabric of Example 6, except that a post-entanglement bonding step was carried out instead of the drying step after the entanglement step in Example 6. The post-entanglement bonding step was carried out by heating for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine. In the post-entanglement bonding step, the fibers were thermally bonded (bonded) to each other by the sheath component of fiber 1.

<Production of nonwoven fabric of Example 9>
Fiber 1 and fiber 2 were mixed in a mixing ratio of 7:3 (mass ratio) and a parallel carding machine was used to produce fiber web A. The basis weight (target basis weight) of fiber web A was 30 g/ ^m2 .
[Adhesion process/cooling process]
The fiber web A was heated for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine, thereby thermally bonding (adhesion treatment) the fibers together via the sheath component of fiber 1. After the thermal bonding (adhesion treatment), the fiber web was subjected to a cooling step in an atmosphere at room temperature of 20°C by natural cooling.
[Base sheet lamination process]
A polypropylene scrim (manufactured by JX ANCI Corporation, product name Conwednet) with a basis weight of approximately 5.2 g/ ^m2 , opening dimensions of 11.3 mm, and an opening ratio of 96% was laminated to the hot air-blown surface of the fibrous web A after the bonding and cooling processes to obtain a composite web. The stress at 10% elongation of this scrim was 12.8 N/5 cm in the MD direction and 13.7 N/5 cm in the CD direction, and the density (at a load of 1.96 kPa) was 0.017 g/ ^cm3 .
[Web Lamination Process]
Fiber 1 and fiber 2 were mixed in a mixing ratio of 7:3 (mass ratio), and a parallel carding machine was used to produce fiber web B having a target weight of 25 g/ ^m2. A scrim was laminated on the composite web so that it was sandwiched between fiber webs A and B, thereby obtaining a laminated web.

[Full-scale entangling process]
The above-mentioned laminated web was placed on a plain weave net with a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90. While the laminated web was advanced at a speed of 4 m/min, a water supply device was used to spray a columnar water stream at a water pressure of 2.0 MPa onto the surface of the fiber web B of the laminated web. The nozzle of the water supply device had orifices with a hole diameter of 0.12 mm spaced 0.6 mm apart. The distance between the surface of the laminated web and the orifices was 15 mm. After the bonding process, the fiber web A, composite web, and laminated web were subjected to a full-surface entanglement process without being wound up on a roll.

[Partial confounding process]
After the full-surface entanglement process, the laminated web was placed on a 25-mesh plain-weave support (warp and weft densities of both 25 threads/inch) made of monofilaments with a wire diameter of 0.7 mm, and a columnar water stream was sprayed onto the surface of the fibrous web A of the laminated web. This entanglement process resulted in the formation of grooves, or highly entangled regions, extending along the MD direction of the nonwoven fabric where the water stream was sprayed. The areas not sprayed with the water stream became less entangled regions, forming ridges. The highly entangled and less entangled regions were alternately arranged in the CD direction of the nonwoven fabric. The nozzle of the water supply machine used in the full-surface entanglement process was the same as that used in the full-surface entanglement process, but some of the multiple orifices were blocked to prevent the water stream from coming out, so that the widths of the formed ridges and grooves were each 6 mm. The laminated web was advanced at a speed of 4 m/min, the water pressure of the columnar water stream was 4.5 MPa, and the distance between the surface of the laminated web and the orifice was 15 mm. A pattern in which openings were arranged in a staggered pattern was formed in the grooves. The area of each aperture was 1.05 mm ² , and the distance between the centers of the nearest apertures was 1.5 mm.

[Drying process]
The laminated web after the entangling step was dried by heating for about 5 seconds using a hot air penetration type heat treatment machine by blowing hot air at 80° C., to obtain a nonwoven fabric of Example 9.

<Production of nonwoven fabric of Example 10>
A nonwoven fabric of Example 10 was obtained in the same manner as in Example 9, except that the partial entanglement step was changed as follows.
[Partial confounding process]
The laminated web was placed on the plain weave net used in the full-surface entanglement process, and columnar water streams were sprayed onto the surface of the fiber web A of the laminated web. This entanglement process resulted in linear grooves of highly entangled portions extending along the MD direction of the nonwoven fabric at the locations where the water streams were sprayed. Locations where the water streams were not sprayed became less entangled portions, forming ridges. The nozzle of the water supply machine used was a nozzle with orifices having a hole diameter of 0.2 mm spaced 7 mm apart. The laminated web was advanced at a speed of 4 m/min, the water pressure of the columnar water streams was 4.5 MPa, and the distance between the surface of the laminated web and the orifices was 15 mm.

<Production of nonwoven fabric of Example 11>
The nonwoven fabric of Example ¹¹ was obtained in the same manner as that for producing the nonwoven fabric of Example 9, except that the base sheet was a spunbond nonwoven fabric made of polyethylene terephthalate (manufactured by Toyobo Co., Ltd., product name: Ekure) having a basis weight of approximately 10.8 g/m², and that the basis weight of fibrous web B was 20 g/ ^m² . The stress at 10% elongation of this spunbond nonwoven fabric was 6.8 N/5 cm in the MD direction and 1.9 N/5 cm in the CD direction, and the density (under a load of 1.96 kPa) was 0.098 g/ ^cm³ .

<Production of nonwoven fabric of Example 12>
The nonwoven fabric of Example ¹² was obtained in the same manner as that for producing the nonwoven fabric of Example 10, except that the base sheet was a spunbond nonwoven fabric made of polyethylene terephthalate (manufactured by Toyobo Co., Ltd., product name: Ekure) having a basis weight of approximately 10.8 g/m², and that the basis weight of fibrous web B was 20 g/ ^m² . The stress at 10% elongation of this spunbond nonwoven fabric was 6.8 N/5 cm in the MD direction and 1.9 N/5 cm in the CD direction, and the density (under a load of 1.96 kPa) was 0.098 g/ ^cm³ .

<Production of Nonwoven Fabric of Comparative Example 1>
The nonwoven fabric of Comparative Example 1 was obtained in the same manner as the nonwoven fabric of Example 5, except that the bonding step and the cooling step were not carried out after the fiber web was produced.

<Production of Nonwoven Fabric of Comparative Example 2>
The nonwoven fabric of Comparative Example 2 was obtained in the same manner as in Example 6, except that the bonding process and cooling process were not carried out after the fiber web was produced.

<Production of nonwoven fabric of Comparative Example 3>
The nonwoven fabric of Comparative Example 3 was obtained in the same manner as the nonwoven fabric of Example 5, except that the bonding step and cooling step were not performed after producing the fiber web in Example 5, and a post-entanglement bonding step was performed instead of the drying step after the entanglement step. The conditions for the post-entanglement bonding step were the same as those for Example 7.

<Production of nonwoven fabric of Comparative Example 4>
The nonwoven fabric of Comparative Example 4 was obtained in the same manner as in Example 6, except that the bonding step and cooling step were not performed after producing the fiber web, and a post-entanglement bonding step was performed instead of the drying step after the entanglement step. The conditions for the post-entanglement bonding step were the same as those for Example 8.

<Production of nonwoven fabric of Example 13>
[Adhesion process/cooling process]
A fiber web was produced using a parallel carding machine using only fiber 1. The target weight of the fiber web was 60 g/ ^m2 .
This fiber web was heated for about 5 seconds by blowing hot air at 135°C using a hot air penetration type heat treatment machine, thereby thermally bonding (adhesion treatment) the fibers together via the sheath component of fiber 1. After thermal bonding (adhesion treatment), the fiber web was subjected to a cooling step in an atmosphere of room temperature (20°C) by natural cooling.

[Full-scale entangling process]
The above-mentioned fiber web was placed on a plain weave net with a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh count of 90. While the fiber web was traveling at a speed of 4 m/min, a water supply device was used to spray a columnar water stream at a water pressure of 1.5 MPa onto the surface of the fiber web on the side where the hot air had been blown. The nozzle of the water supply device had orifices with a hole diameter of 0.12 mm arranged at 0.6 mm intervals. The distance between the surface of the fiber web and the orifices was 15 mm. After the bonding process, the fiber web was subjected to the entanglement process without being wound up on a roll.

[Partial confounding process]
The nonwoven fabric was placed on a plain weave net used in the full-surface entanglement process, and a columnar water stream was sprayed onto the surface opposite to the surface onto which the water stream was sprayed in the full-surface entanglement process. This entanglement process resulted in linear grooves of highly entangled portions extending along the MD direction of the nonwoven fabric at the locations where the water stream was sprayed. Locations where the water stream was not sprayed became less entangled portions, forming ridges. The nozzle of the water supply machine used was a nozzle with orifices having a hole diameter of 0.2 mm spaced 7 mm apart. The speed at which the fiber web was advanced was 4 m/min, the water pressure of the columnar water stream was 3.0 MPa, and the distance between the surface of the fiber web and the orifice was 15 mm.

[Drying process]
The fiber web after the entangling step was dried by heating for about 5 seconds using a hot air penetration type heat treatment machine by blowing hot air at 80° C., to obtain a nonwoven fabric of Example 13.

<Production of nonwoven fabric of Comparative Example 5>
The nonwoven fabric of Comparative Example 5 was obtained in the same manner as the nonwoven fabric of Example 13, except that the bonding step and cooling step were not performed after producing the fiber web in Example 13, and a post-entanglement bonding step was performed instead of the drying step after the entanglement step. The conditions for the post-entanglement bonding step were the same as those for Example 8.

The nonwoven fabric was evaluated as follows.
<Angle of fiber bond intersection>
The nonwoven fabric was cut in the longitudinal direction (MD direction, more specifically, the direction parallel to the traveling direction of the belt conveyor of the heat treatment machine and water jet treatment machine that treated the nonwoven fabric), and the cut surface was observed with a scanning electron microscope (SEM, magnification: 60x). The nonwoven fabric was divided into three equal parts in the thickness direction, and the apparent angle between the two fibers that form the bonded intersection was examined near the top and bottom of the nonwoven fabric and near the middle (middle part). The apparent angles were examined at at least 15 locations, and the average value was calculated. The side on which the water jet was sprayed during the partial entanglement process was defined as the top, and the side on the opposite side was defined as the bottom.

<Adhesive intersection index A>
The front and back surfaces of the nonwoven fabric were observed with a scanning electron microscope (SEM, accelerating voltage: 10.0 kV, magnification: 100x). The number of fiber bonding intersections per area was counted for each of the SEM images taken. The number of fiber bonding intersections was counted for a total of six SEM images, three for each of the front and back surfaces of the nonwoven fabric, and the average value was taken as the number of fiber bonding intersections I (unit: pieces/ ^mm2 ).
The adhesive intersection point ratio P (0≦P≦1) was calculated from the fineness (dtex) of the non-adhesive fiber (fiber 2) and adhesive fiber (fiber 1) constituting the nonwoven fabrics of the Examples and Comparative Examples and their mixing ratios (mass%) in the nonwoven fabric, according to the following formula:
During the ceremony,
α _i represents the mixing ratio (mass%) of the i-th non-adhesive fiber,
_xi represents the fineness (dtex) of the i-th non-adhesive fiber;
β _j represents the mixing ratio (mass%) of the jth adhesive fiber,
_yj represents the fineness (dtex) of the jth adhesive fiber.
From the number of adhesive intersections I and the proportion of adhesive intersections P, the adhesive intersection index A (unit: pieces/mm ² ) was calculated according to the following formula.
Adhesive intersection index A=I/(P ² )

In the case of a two-layer structure, the adhesive intersection ratio P on the front or back side is calculated based on the cotton blending state on the front or back side. The adhesive intersection index A is still calculated by averaging the three front and three back side values.

<Thickness and density of nonwoven fabric>
The thickness of the nonwoven fabric was measured using a thickness measuring device (THICKNESS GAUGE Model CR-60A (trade name) manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd.) while a load of 294 Pa or 1.96 kPa was applied to the nonwoven fabric.
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 1.96 kPa.

<Strength and elongation>
The strength and elongation were measured in accordance with JIS L 1913:2010 6.3. Using a constant-speed tension tensile tester, a tensile test was conducted under the conditions of a sample piece (nonwoven fabric) width of 5 cm, a grip spacing of 10 cm, and a tensile speed of 30±2 cm/min. The load value at break (tensile strength), elongation, and stress at 10% elongation were measured. The tensile test was conducted in the machine direction (MD) and the cross direction (CD) of the nonwoven fabric as the tensile direction. The evaluation results were all expressed as the average of the values measured for three samples.

<Fluffing index>
The abrasion test was carried out using a Martindale fluff tester (manufactured by James Heal, trade name "Martindale Abrasion and Pilling Tester No. 1309").
Two samples (one with a diameter of 140 mm and one with a diameter of 38 mm) were prepared for the nonwoven fabrics of the Examples and Comparative Examples. A 140 mm diameter felt was placed on an abrading table, and the 140 mm diameter sample was layered on SM25 abrasive cloth and secured with a clamping ring. Next, a 38 mm diameter sample and a 38 mm diameter polyurethane were placed on a sample holder. The measurement conditions were as follows: the sample holder was placed on the abrading table without a loading weight. The friction test was performed with eight rotations and a motion of 60.5 mm Lissajous. For the Examples and Comparative Examples processed using a hot air penetration heat treatment machine, the friction test was performed so that the surfaces opposite to the hot air contacted each other. After the measurement was completed, the nonwoven fabric on the sample holder side was observed, and the fluffing state was determined based on the following two criteria (the state of the nonwoven fabric after measurement when viewed from directly above (surface state) and the state of the nonwoven fabric after measurement when viewed from directly to the side (degree of fluffing)), which was calculated as the total score (out of 10 points). A total of 6 points or more is considered to indicate that fluffing is suppressed, and a total of less than 9 points is considered to indicate a high degree of freedom of the fibers. For each Example or Comparative Example, the evaluation test was performed twice, and the average of the two scores was used as the fluffing index for each Example or Comparative Example.
Surface condition 5: Very good (no surface irregularities)
4: Good (very little surface irregularity)
3: Normal (there is little surface irregularity, not noticeable)
2: Poor (there is some noticeable surface irregularity)
1: Very bad (holes on the surface)
Fluffiness: 5: Very good (no fluffing)
4: Good (very little pilling)
3: Normal (some pilling is not noticeable)
2: Poor (some noticeable pilling)
1: Very bad (lots of fluff)

<Lift shedding measurement test>
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.

<Dirt collection ability>
[Dust collection ability]
0.20 g of test powders (seven types) conforming to JIS Z 8901 were uniformly dispersed in a rectangular area measuring 5 cm in length and 15 cm in width (hereinafter referred to as the "dust dispersion area") at approximately the center of the surface of a white acrylic plate, and the test powders (dust) were wiped off using nonwoven fabrics (26 cm in length, 16 cm in width) from the Examples and Comparative Examples as wipers.

The wiping was performed by attaching the nonwoven fabric to a wiper jig (product name: Quickle Wiper [tool body] head, manufactured by Kao Corporation) so that the area contributing to wiping was 26 cm vertically and 16 cm horizontally, with the upper surface (the surface onto which the water jet was sprayed during the partial entanglement process) being the wiping surface, and applying a weight of 400 g. The wiper was moved back and forth once across the surface of the white acrylic plate to wipe.

More specifically,
- Place the wiper in the center of the dust distribution area so that the vertical direction of the wiper coincides with the vertical direction of the dust distribution area;
From there, move the wiper 250 mm in the direction toward the left end of the dust dispersion area and rub the dust (white acrylic plate).
Then, move the wiper 500 mm in the direction toward the right end of the dust dispersion area,
The wiper was further moved 250 mm in the direction toward the left end of the dust dispersion area and made one reciprocating motion.

After the wiper had been moved back and forth once, the dust collection rate was calculated from the pre-measured mass of the nonwoven fabric and the mass of the nonwoven fabric measured after wiping. For each nonwoven fabric, wiping was measured three times with the wiping surface of the nonwoven fabric fresh, and the average value was used as the dust collection rate.

[Hair collection ability (wet state)]
A total of five hairs (approximately 5 cm long) were placed on the flooring with a gap between them, three hairs arranged horizontally and two hairs arranged vertically, and the hairs were wiped off with the nonwoven fabrics of the Examples and Comparative Examples.

Wiping was performed in a wet state, with 300 parts by weight of distilled water impregnated into 100 parts by weight of nonwoven fabric. The nonwoven fabric was attached to a wiper tool (product name: Quickle Wiper [tool body] head, manufactured by Kao Corporation) with the upper surface (the surface onto which the water jet was sprayed during the partial entanglement process) facing the wiping surface, so that the area contributing to wiping was 26 cm vertically and 16 cm horizontally, and a weight of 400 g was applied. Wiping was performed using the same method as used in the dust capture evaluation above, with the wiper moving back and forth over the hair. After wiping, the capture rate (%) was calculated from the number of hairs wiped off the flooring. For each nonwoven fabric, wiping was measured three times with the wiping surface of the nonwoven fabric fresh, and the average value was used as the hair capture rate.

The evaluation results for each example and comparative example are shown in Tables 1 to 5.

All of the nonwoven fabrics of the Examples exhibited superior dust collection and hair collection in a wet state compared to the nonwoven fabrics of the Comparative Examples. Furthermore, all of the nonwoven fabrics of the Examples were relatively resistant to pilling.

The nonwoven fabrics of Comparative Examples 3 and 4 were produced by carrying out the entanglement step without carrying out the bonding step, and then carrying out the bonding step after entanglement, so it is presumed that the distance between the fibers became considerably short in the entanglement step, and the fibers were bonded together in this state. As a result, it is thought that the bonded intersection index A was large and fuzzing was unlikely to occur.
The nonwoven fabrics of Comparative Examples 1 and 2 were produced by a method that did not include any bonding step, and therefore the strength of the nonwoven fabrics was low and they were prone to fluffing.
In the nonwoven fabrics of Comparative Examples 1 to 4, the bonding step was not performed before the entangling step, and therefore the entanglement of the fibers in the entanglement step proceeded more easily than in Examples, resulting in a smaller thickness of the nonwoven fabric. This is thought to be why the bulk was smaller overall, and both the dust collection ability and the hair collection ability were lower than in Examples.

Comparing Example 5 and Example 7, Example 7, which was produced using a method including a post-entanglement bonding process, had a higher bonded intersection index A and was less likely to pill. Similarly, comparing Example 6 and Example 8, which was produced using a method including a post-entanglement bonding process, was less likely to pill. Furthermore, comparing Example 5 and Example 7, Example 7 had a greater thickness, a lower fiber density, and was bulkier. This is thought to be because Example 7 was produced by drying and re-bonding with hot air after the entanglement process, eliminating settling due to the weight of water, and because the application of hot air restored the bulk. In other words, in Example 7, the fibers were re-bonded in a bulky state, which likely fixed the fibers together while maintaining a relatively high bulk, resulting in a bulky nonwoven fabric. The same is true when comparing Example 6 and Example 8.

Comparing Example 1 and Example 7, the nonwoven fabric of Example 1 was less bulky and had weaker MD nonwoven fabric strength. This is thought to be because, in Example 1, fibrous web B was laminated to fibrous web A and subjected to an entanglement treatment without undergoing a bonding process, resulting in the fibers of fibrous web B becoming more tightly entangled. The same is true when comparing Example 2 and Example 8.

Comparing Example 1 and Example 3, the nonwoven fabric of Example 1 was bulkier. This is thought to be because Example 3 contained a higher proportion of cellulosic fibers, which are easily entangled by hydroentanglement treatment. In Example 3, entanglement between fibers progressed more and the distance between fibers became shorter, resulting in an increased number of bonded points and a higher bonded intersection index A than in Example 1. However, pilling was more likely to occur than in Example 1. This is thought to be because Example 3 contained a lower proportion of adhesive fibers, resulting in fewer bonded points between adhesive fibers, which are more effective in preventing pilling. However, this speculation does not limit the present disclosure in any way. The same is true when comparing Example 2 and Example 4.

When comparing Example 9, which contains a scrim, with Examples 1 and 7, which were produced without a scrim and by performing a post-entanglement bonding process, the nonwoven fabric of Example 9 exhibited a higher stress at 10% elongation in both the MD and CD directions than either of the other Examples. When comparing Example 11, which contains a spunbond nonwoven fabric, with Examples 1 and 7, which were produced without a spunbond nonwoven fabric and by performing a post-entanglement bonding process, the stress at 10% elongation of Example 11 was higher than that of Example 7 and slightly lower than that of Example 1, but still usable. Similar trends were observed in comparisons of Example 10 with Examples 2 and 8, and Example 12 with Examples 2 and 8. Furthermore, other properties (e.g., collection ability, fluff index, and amount of fluff shedding) of Examples 9 to 12, which contain scrims or spunbond nonwoven fabrics, were comparable to those of the other Examples. These findings demonstrate that by using a base sheet such as a scrim or spunbond nonwoven fabric, it is possible to obtain a nonwoven fabric that is equivalent to or better than a nonwoven fabric without a base sheet that has undergone a post-entanglement bonding process in terms of stress at 10% elongation and other performance, even without performing a post-entanglement bonding process.

Since Example 13 is a nonwoven fabric containing only adhesive fibers, it was less prone to pilling than Example 6. On the other hand, since Example 13 does not contain any fibers other than adhesive fibers, the degree of freedom of the fibers is reduced, and its dust collection and hair collection capabilities were somewhat lower than those of Example 6. Comparative Example 5, which was produced without performing the bonding step before the entanglement step, was less bulky overall, and its dust collection and hair collection capabilities were both lower than those of Example 13.

[Sesame seed collection ability (wet state)]
The nonwoven fabrics of each Example and Comparative Example were evaluated for their sesame seed collection ability in a wet state. To evaluate sesame seed collection ability, 10 sesame seeds were arranged at intervals in three rows (3-4-3 rows) on a flooring surface, and the nonwoven fabric was used to wipe the flooring in the same manner as in the evaluation of hair collection ability (wet state). After wiping, the collection rate (%) was calculated from the number of sesame seeds wiped off from the flooring. For each nonwoven fabric, the wiping was measured three times with the wiping surface of the nonwoven fabric fresh, and the average value was taken as the sesame seed collection rate.
Table 6 shows the sesame seed collection performance of each example and comparative example.

As shown in Table 6, the nonwoven fabrics of Examples 9 to 12, which contained scrim or spunbond nonwoven fabric, exhibited relatively high sesame capture capacity in a wet state. Sesame capture capacity is an indicator of the ability to wipe away dirt that is slightly larger than dust or hair, such as food debris that occurs in everyday life. Nonwoven fabrics containing scrim or spunbond nonwoven fabric have a relatively high degree of fiber flexibility due to the single bonding process, and are less likely to twist when wet. This makes them excellent at wiping away such slightly larger dirt, and combined with their dust and hair capture capacity, they can be provided as wipers with excellent wiping ability.

This embodiment includes the following aspects.
(Aspect 1)
A method for producing a nonwoven fabric comprising cellulosic fibers and adhesive fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
Method for manufacturing nonwoven fabric.
(Aspect 2)
A method for producing a nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a substrate sheet integrated with the fiber layer by entanglement of the fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step;
Method for manufacturing nonwoven fabric.
(Aspect 3)
A method for producing a nonwoven fabric according to Aspect 2, wherein the substrate sheet is a long-fiber nonwoven fabric, a wet-laid nonwoven fabric, or a mesh sheet.
(Aspect 4)
The method for producing a nonwoven fabric of aspect 1, further comprising a web laminating step, after the bonding step and before the entangling step, of laminating another fibrous web containing cellulosic fibers and adhesive fibers onto the fibrous web to obtain a laminated web.
(Aspect 5)
A method for producing a nonwoven fabric according to aspect 2 or 3, further comprising a web laminating step, after the bonding step and before the entangling step, of laminating another fibrous web containing cellulosic fibers and adhesive fibers such that the base sheet is positioned between the fibrous web and the other fibrous web, to obtain a laminated web.
(Aspect 6)
A method for producing a nonwoven fabric according to aspect 4 or 5, wherein the other fiber web contains 20% by mass or more and 80% by mass or less of the adhesive fiber.
(Aspect 7)
Aspect 7. The method for producing a nonwoven fabric according to any one of aspects 1 to 6, wherein the highly entangled portions and the less entangled portions are alternately arranged in the CD direction of the nonwoven fabric.
(Aspect 8)
Aspect 8. The method for producing a nonwoven fabric according to any one of Aspects 1 to 7, wherein the entangling step comprises a hydroentangling treatment.
(Aspect 9)
Aspect 9. The method for producing a nonwoven fabric according to any one of aspects 1 to 8, wherein the entangling step includes a full-surface entangling step of entangling fibers across the entire fiber web, the entire composite web, or the entire laminate web, and the fiber web, the composite web, or the laminate web is subjected to the partial entangling step after the full-surface entangling step.
(Aspect 10)
A method for producing a nonwoven fabric according to aspect 9, wherein the full-area entanglement step and the partial entanglement step are both carried out by hydroentanglement, and the water pressure of the hydroentanglement step in the full-area entanglement step is lower than the water pressure of the hydroentanglement step in the partial entanglement step.
(Aspect 11)
A method for producing a nonwoven fabric according to aspect 10, wherein both the full-scale entanglement step and the partial entanglement step are carried out by a hydroentanglement treatment in which a water stream is sprayed onto only one surface of the fiber web, the composite web, or the laminate web, and the surface onto which the water stream is sprayed in the partial entanglement step is the opposite surface to the surface onto which the water stream is sprayed in the full-scale entanglement step.
(Aspect 12)
Aspect 12. The method for producing a nonwoven fabric according to any one of Aspects 1 to 11, wherein an open pattern is formed in the highly entangled portion in the partially entangled step.
(Aspect 13)
The bonding step includes a hot air processing treatment of applying hot air to one surface of the fiber web or the composite web,
The entanglement step includes a hydroentanglement treatment,
The hydroentanglement treatment includes spraying a water stream first onto the surface of the fiber web or the composite web that has been hit with hot air, or spraying a water stream first onto the surface of the fiber web or the composite web that has been hit with hot air, rather than onto the surface that has not been hit with hot air.
(Aspect 14)
A method for producing a nonwoven fabric according to any of aspects 1 to 13, comprising a cooling step of cooling the fiber web and/or the composite web between the bonding step and the entangling step, between the bonding step and the base sheet laminating step, or between the bonding step and the web laminating step, and/or a cooling step of cooling the laminate web between the web laminating step and the entangling step.
(Aspect 15)
Aspect 15. The method for producing a nonwoven fabric according to any one of Aspects 1 to 14, wherein the fiber web, the composite web, or the laminate web is not wound up into a roll at any time after the bonding step and before the entangling step.
(Aspect 16)
16. The method for producing a nonwoven fabric according to any one of aspects 1 to 15, wherein, in the partially entangled step, the less entangled portions are formed so that the width of the less entangled portions is greater than 5 mm and not greater than 50 mm.
(Aspect 17)
Aspect 17. The method for producing a nonwoven fabric according to any one of aspects 1 to 16, wherein the fiber web comprises 55% by mass or more and 80% by mass or less of the adhesive fibers.
(Aspect 18)
Aspect 18. The method for producing a nonwoven fabric according to any one of Aspects 1 to 17, wherein the adhesive fibers comprise core-sheath composite fibers.
(Aspect 19)
Aspect 19. The method for producing a nonwoven fabric according to any one of aspects 1 to 18, further comprising, after the entangling step, another bonding step of bonding fibers to each other with the adhesive fiber.
(Aspect 20)
A nonwoven fabric comprising cellulosic fibers and adhesive fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Aspect 21)
A nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Aspect 22)
A nonwoven fabric according to claim 21, wherein the substrate sheet is a long-fiber nonwoven fabric, a wet-laid nonwoven fabric, or a net sheet.
(Aspect 23)
A nonwoven fabric according to aspect 21 or 22, wherein the base sheet is sandwiched in a cross section in the thickness direction by fibrous layers containing the cellulosic fibers and adhesive fibers.
(Aspect 24)
Aspect 24. The nonwoven fabric according to any one of aspects 20 to 23, wherein the nonwoven fabric comprises 55% by mass or more and 80% by mass or less of the adhesive fibers.
(Aspect 25)
Aspect 25. The nonwoven fabric according to any one of aspects 20 to 24, wherein the adhesive fibers comprise core-sheath composite fibers.
(Aspect 26)
Aspect 26. The nonwoven fabric according to any one of aspects 20 to 25, wherein the less entangled portions have a width of more than 5 mm and not more than 50 mm.
(Aspect 27)
A wiper comprising the nonwoven fabric according to any one of aspects 20 to 26.
(Aspect 28)
A method for producing a nonwoven fabric containing adhesive fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
Method for manufacturing nonwoven fabric.
(Aspect 29)
A method for producing a nonwoven fabric comprising a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step;
Method for manufacturing nonwoven fabric.
(Aspect 30)
A nonwoven fabric comprising adhesive fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Aspect 31)
A nonwoven fabric comprising a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include adhesive points between each other,
The adhesive fibers include entangled portions,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as determined by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Aspect 32)
A wiper comprising the nonwoven fabric of aspect 30 or 31.

The nonwoven fabric manufacturing method disclosed herein involves subjecting a fiber web containing specified fibers to a bonding process, followed by an entanglement treatment including a partial entanglement process, thereby producing a nonwoven fabric containing highly entangled portions where the fibers are tightly entangled, and less entangled portions where the fibers have a high degree of freedom. Therefore, the manufacturing method disclosed herein can produce a nonwoven fabric that is excellent in dirt collection, has greater strength than nonwoven fabrics manufactured using only an entanglement process, is easier to handle, and is less likely to pill, making it suitable for use as a wiper.

10 Highly entangled portion 20 Lowly entangled portion 100 Nonwoven fabric

Claims (26)

A method for producing a nonwoven fabric comprising cellulosic fibers and adhesive fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
The bonding step includes a hot air processing treatment of applying hot air to the fiber web,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
Method for manufacturing nonwoven fabric. A method for producing a nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step,
A method for producing a nonwoven fabric, wherein the bonding step includes a hot air processing treatment of applying hot air to the fiber web or the composite web. The method for producing a nonwoven fabric according to claim 2, wherein the substrate sheet is a long-fiber nonwoven fabric, a wet-laid nonwoven fabric, or a mesh sheet. A method for producing a nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a substrate sheet integrated with the fiber layer by entanglement of the fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step,
The method for producing a nonwoven fabric , wherein the substrate sheet is a wet-laid nonwoven fabric or a mesh sheet. The method for producing a nonwoven fabric according to claim 1 further comprises a web laminating step, performed after the bonding step and before the entangling step, of laminating another fibrous web containing cellulosic fibers and adhesive fibers onto the fibrous web to obtain a laminated web. The method for producing a nonwoven fabric according to any one of claims 2 to 4 further comprises a web laminating step, performed after the bonding step and before the entangling step, of laminating another fibrous web containing cellulosic fibers and adhesive fibers so that the base sheet is positioned between the fibrous web and the other fibrous web to obtain a laminated web. The method for producing a nonwoven fabric according to any one of claims 1 to 6 , wherein the entangling step includes a hydroentangling treatment. The method for producing a nonwoven fabric according to any one of claims 1 to 7, wherein the entangling step includes a full-surface entangling step of entangling fibers across the entire fiber web, the entire composite web, or the entire laminate web, and the fiber web, the composite web, or the laminate web is subjected to the partial entangling step after the full- surface entangling step. A method for producing a nonwoven fabric comprising cellulosic fibers and adhesive fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
the entanglement step includes a full-surface entanglement step of entangling fibers throughout the entire fiber web, and the fiber web is subjected to the partial entanglement step after the full-surface entanglement step,
The method for producing a nonwoven fabric, wherein the full-surface entanglement step and the partial entanglement step are both carried out by hydroentanglement, and the water pressure of the hydroentanglement step in the full-surface entanglement step is lower than the water pressure of the hydroentanglement step in the partial entanglement step. 10. The method for producing a nonwoven fabric according to claim 9, wherein both the full-surface entanglement step and the partial entanglement step are carried out by a hydroentanglement treatment in which a water stream is sprayed onto only one surface of the fiber web, and the surface onto which the water stream is sprayed in the partial entanglement step is the opposite surface to the surface onto which the water stream is sprayed in the full-surface entanglement step. A method for producing a nonwoven fabric comprising cellulosic fibers and adhesive fibers, comprising:
In a fiber web containing the cellulosic fiber and the adhesive fiber, the method includes a bonding step of bonding fibers together with the adhesive fiber, and a entanglement step of entangling the fibers together after the bonding step,
the entanglement step includes a partial entanglement step of forming highly entangled portions, in which the degree of entanglement between fibers is higher, and less entangled portions, in which the degree of entanglement between fibers is lower than that of the highly entangled portions, so that the highly entangled portions and the less entangled portions are alternately arranged in a planar view, and the less entangled portions have a width of 2 mm or more and 50 mm or less;
the entanglement step includes a full-surface entanglement step of entangling fibers throughout the entire fiber web, and the fiber web is subjected to the partial entanglement step after the full-surface entanglement step;
The entire entanglement step and the partial entanglement step are both carried out by hydroentanglement treatment, and the water pressure of the hydroentanglement treatment in the entire entanglement step is lower than the water pressure of the hydroentanglement treatment in the partial entanglement step,
In the partially entangled portion, an open pattern is formed in the highly entangled portion. The bonding step includes a hot air processing treatment of applying hot air to one surface of the fiber web or the composite web,
The entanglement step includes a hydroentanglement treatment,
The manufacturing method according to any one of claims 1 to 11, wherein the hydroentanglement treatment includes spraying a water stream first onto the surface of the fiber web or the composite web that has been hit with hot air, or spraying a water stream first onto the surface of the fiber web or the composite web that has been hit with hot air, before spraying a water stream onto the surface of the fiber web or the composite web that has not been hit with hot air. The method for producing a nonwoven fabric according to any one of claims 1 to 12, further comprising a cooling step of cooling the fiber web and/or the composite web between the bonding step and the entangling step, between the bonding step and the base sheet laminating step, or between the bonding step and the web laminating step, and/or a cooling step of cooling the laminated web between the web laminating step and the entangling step . The method for producing a nonwoven fabric according to any one of claims 1 to 13 , wherein the fiber web, the composite web, or the laminate web is not wound up into a roll at any time after the bonding step and before the entangling step. The method for producing a nonwoven fabric according to any one of claims 1 to 14 , further comprising, after the entangling step, another bonding step of bonding fibers together with the adhesive fiber. A nonwoven fabric comprising cellulosic fibers and adhesive fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less in the following test,
A nonwoven fabric having an adhesive intersection index A of 1/mm ² to 60/mm ² as determined by the following procedure .
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk. f) Repeat the above steps a) to e) for n = 3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Adhesive intersection index A)
The front and back surfaces of the nonwoven fabric are observed using a scanning electron microscope (SEM, accelerating voltage: 10.0 kV, magnification: 100x). The number of fiber intersections per area is counted for each of the SEM images taken. The number of fiber intersections is counted for a total of six SEM images, three for each of the front and back surfaces of the nonwoven fabric, and the average value is taken as the number of fiber intersections I (unit: pieces/ ^mm2 ).
The adhesive intersection ratio P (0≦P≦1) is calculated from the fineness (dtex) of the non-adhesive fibers and adhesive fibers constituting the nonwoven fabric and their mixing ratios (mass%) in the nonwoven fabric according to the following formula.
During the ceremony,
α _i represents the mixing ratio (mass%) of the i-th non-adhesive fiber,
_xi represents the fineness (dtex) of the ith non-adhesive fiber;
β _j represents the mixing ratio (mass%) of the jth adhesive fiber,
_yj represents the fineness (dtex) of the jth adhesive fiber.
From the number of adhesive intersections I and the adhesive intersection proportion P, the adhesive intersection index A (unit: pieces/mm ² ) is calculated according to the following formula.
Adhesive intersection index A=I/(P ² ) A nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
The adhesive intersection index A obtained by the following procedure is 1/mm ² to 60/mm ² ,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off.
(Adhesive intersection index A)
The front and back surfaces of the nonwoven fabric are observed using a scanning electron microscope (SEM, accelerating voltage: 10.0 kV, magnification: 100x). The number of fiber intersections per area is counted for each of the SEM images taken. The number of fiber intersections is counted for a total of six SEM images, three for each of the front and back surfaces of the nonwoven fabric, and the average value is taken as the number of fiber intersections I (unit: pieces/ ^mm2 ).
The adhesive intersection ratio P (0≦P≦1) is calculated from the fineness (dtex) of the non-adhesive fibers and adhesive fibers constituting the nonwoven fabric and their mixing ratios (mass%) in the nonwoven fabric according to the following formula.
During the ceremony,
α _i represents the mixing ratio (mass%) of the i-th non-adhesive fiber,
_xi represents the fineness (dtex) of the i-th non-adhesive fiber;
β _j represents the mixing ratio (mass%) of the jth adhesive fiber,
_yj represents the fineness (dtex) of the jth adhesive fiber.
From the number of adhesive intersections I and the adhesive intersection proportion P, the adhesive intersection index A (unit: pieces/mm ² ) is calculated according to the following formula.
Adhesive intersection index A=I/(P ² ) The nonwoven fabric according to claim 17 , wherein the substrate sheet is a long-fiber nonwoven fabric, a wet-laid nonwoven fabric, or a net sheet. A nonwoven fabric comprising a fiber layer containing cellulosic fibers and adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers,
The adhesive fibers include bonded portions between each other and/or bonded portions between the adhesive fibers and the cellulosic fibers,
The cellulose-based fibers include entangled portions between each other and/or entangled portions between the cellulose-based fibers and the adhesive fibers,
The nonwoven fabric includes a highly entangled portion in which the degree of entanglement between fibers is higher and a low entangled portion in which the degree of entanglement between fibers is lower,
the highly entangled portions and the less entangled portions are alternately arranged in the CD direction in a plan view,
The width of the less entangled portion is 2 mm or more and 50 mm or less,
the base sheet is a long-fiber nonwoven fabric, a wet-laid nonwoven fabric, or a mesh sheet,
A nonwoven fabric, wherein the amount of fluff shedding on at least one surface of the nonwoven fabric is 1.5 mg or more and 20 mg or less, as measured by the following test.
(Lifting amount measurement test)
a) A disk (70 mm diameter, 350 g) covered with urethane foam (trade name Malt Filter MF-30, manufactured by Inoac Corporation, thickness 5 mm) was attached to a rotating shaft so that the rotating shaft was positioned 20 mm off from the center of the disk.
b) The same urethane foam as above is laid on the table, and the nonwoven fabric is fixed on top of it so that one side of the nonwoven fabric is exposed.
c) The disk is placed on the nonwoven fabric, with the only load applied to the nonwoven fabric being the disk's own weight.
d) Rotate the rotating shaft to rotate the disk over the nonwoven fabric. Three sets of rotations are performed, each set consisting of three clockwise rotations and three counterclockwise rotations. The rotation speed is approximately 3 seconds per rotation.
e) After three sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disk.
f) Repeat steps a) to e) above for n=3 pieces of nonwoven fabric. Measure the mass of the fallen fibers for each of the three pieces of nonwoven fabric, and calculate the average value to determine the amount of fluff that has fallen off. The nonwoven fabric according to any one of claims 17 to 19 , wherein the base sheet is sandwiched between fibrous layers containing the cellulosic fibers and adhesive fibers in a cross section in the thickness direction. The nonwoven fabric according to any one of claims 16 to 20 , wherein the nonwoven fabric contains 55% by mass or more and 80% by mass or less of the adhesive fibers. The nonwoven fabric according to any one of claims 16 to 21 , wherein the adhesive fibers comprise core-sheath type composite fibers. The nonwoven fabric according to any one of claims 16 to 22 , wherein the less entangled portions have a width of more than 5 mm and not more than 50 mm. A wiper comprising the nonwoven fabric according to any one of claims 16 to 23 . A method for producing a nonwoven fabric containing adhesive fibers, comprising:
In a fiber web containing the adhesive fibers, the method includes a bonding step of bonding fibers to each other with the adhesive fibers, and an entanglement step of entangling the fibers to each other after the bonding step,
The bonding step includes a hot air processing treatment of applying hot air to the fiber web,
the entanglement step includes a partial entanglement step of forming highly entangled parts, in which the degree of entanglement between fibers is higher, and less entangled parts, in which the degree of entanglement between fibers is lower than that of the highly entangled parts, so that the highly entangled parts and the less entangled parts are alternately arranged in a plan view, and the less entangled parts have a width of 2 mm or more and 50 mm or less.
Method for manufacturing nonwoven fabric. A method for producing a nonwoven fabric comprising a fiber layer containing adhesive fibers, and a base sheet integrated with the fiber layer by entanglement of the fibers, comprising:
The fiber web includes a bonding step of bonding fibers together with the adhesive fibers, and a entanglement step of entangling the fibers together after the bonding step, and the entanglement step includes a partial entanglement step of forming highly entangled sections in which the degree of entanglement of fibers is higher and less entangled sections in which the degree of entanglement of fibers is lower than that of the highly entangled sections, so that the highly entangled sections and the less entangled sections are alternately arranged in a plan view, and the width of the less entangled sections is 2 mm or more and 50 mm or less,
a base sheet laminating step of laminating the base sheet on the fiber web to obtain a composite web, which is performed before or after the bonding step and before the entangling step,
The bonding step includes a hot air processing treatment of applying hot air to the fiber web or the composite web.
Method for manufacturing nonwoven fabric.