JP2023101408A - Nonwoven fabric for wipers, and wiper - Google Patents

Abstract

To provide a nonwoven fabric suitable for a wiper, which can trap dirt properly with a reduced amount of fibers coming out.SOLUTION: A nonwoven fabric includes a first surface, and a second surface opposite the first surface. Relative to total mass of the nonwoven fabric, water-repellent cellulose fibers are contained by 10 mass% or more and less than 75 mass% and other fibers are contained by more than 25 mass% and 90 mass% or less. At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fibers by 10 mass% or more and the other fibers by 90 mass% or less. The entanglement of the fibers forms an integrated structure.SELECTED DRAWING: None

Description

The present disclosure relates to wiper nonwovens and wipers comprising such nonwovens.

One use of nonwoven fabrics is wipers for wiping dirt from a person's body or objects. For example, in Patent Document 1, a fabric containing hydrophilic fibers and hydrophobic fibers and satisfying a specific relationship between the content of the hydrophobic fibers and the abundance of the hydrophobic fibers on the surface of the fabric is impregnated with a disinfectant solution. A wet wiper is suggested. Further, Patent Document 2 proposes the use of a nonwoven fabric containing a blend of artificial cellulose fibers and hydrophobic artificial cellulose fibers, which is treated with a wetting agent, as a wet wipe.

JP 2016-22272 A Japanese Patent Application Publication No. 2015-507977

To provide a non-woven fabric which is superior in the ability to collect wiped dirt and gives a wiper with less fluff shedding.

A nonwoven fabric according to the present disclosure is a nonwoven fabric having a first surface and a second surface opposite the first surface,
Based on the total mass of the nonwoven fabric, it contains water-repellent cellulose fibers at a ratio of 10% by mass or more and less than 75% by mass, and other fibers at a ratio of more than 25% by mass and 90% by mass or less,
At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fibers at a ratio of 10% by mass or more and the other fibers at a ratio of 90% by mass or less,
are integrated by entangling the fibers,
Nonwoven fabric for wipers.

In the wiper nonwoven fabric of the present disclosure, the fiber layer A constituting one surface of the nonwoven fabric contains water-repellent cellulose fibers at a predetermined ratio, and the ratio of the water-repellent cellulose fibers is set within a predetermined range based on the total mass of the nonwoven fabric. Configuration. With this configuration, when the nonwoven fabric of the present disclosure is used as a wiper, the water-repellent cellulose fibers themselves are easily deformed by the wiping pressure, and the entangling property of the water-repellent cellulose fibers is slightly low. , the voids between the fibers are easily deformed by the wiping pressure, so that the dirt collecting property can be improved. In addition, the wiper nonwoven fabric of the present disclosure makes it possible to reduce the amount of fibers that fall off from the nonwoven fabric (fuzz removal) during wiping, and depending on the configuration, improves the sustained release of liquid when impregnated with liquid. further enable

(Circumstances leading to the nonwoven fabric for wipers of the present disclosure)
In the wet wiper described in Patent Document 1, the hydrophobic fibers on the surface of the fabric are not impregnated with the impregnating liquid, so the hydrophobic fibers do not swell and are not deformed even by the wiping pressure during wiping. Allows for efficient scraping of surface contaminants. In addition, in the wet wiper described in the same document, the wiped dirt is absorbed by a portion having a large ratio of hydrophilic fibers inside the cloth, making it difficult to return. In Patent Document 1, "hydrophobic fiber" is defined as having a property of being unable to contain water, and synthetic fibers and inorganic fibers are exemplified as hydrophobic fibers.

The present inventor constructed the fabric described in Patent Document 1 as a nonwoven fabric and evaluated its wiping performance. In particular, for wipers for cleaning floor surfaces, the ability to collect solid dirt larger than dust such as food waste and hair (the ability to retain the wiped dirt in the wiper) is important. The wiper of Patent Document 1 still has room for improvement in that respect.

The present inventors have studied a configuration for improving the ability to collect relatively large solid dirt, and believe that the deformation of the fibers due to the wiping pressure during wiping may be rather useful for collecting these dirt. I came up with the idea. In other words, when the fibers are deformed to some extent by the wiping pressure, the voids between the fibers partially widen, and after the dirt enters there, the deformed fibers return to their original state, enabling the dirt to be taken in efficiently. I thought it would be

The deformation of the fibers due to the wiping pressure is more likely to occur as the swelling property and thus the hydrophilicity of the fibers increases. The hydrophilicity of nonwoven fabrics affects the sustained release of liquids when used as wet wipes. In general, when the ratio of hydrophilic fibers contained in the nonwoven fabric increases, a large amount of liquid is likely to be released at the beginning of use.

As a result of various investigations in consideration of the above, the present inventors have found that the use of water-repellent cellulose fibers can significantly improve the ability to collect relatively large solid dirt. As will be described later, the water-repellent cellulose fiber has a water-repellent outer peripheral surface and does not easily absorb water. (A portion containing no water-repellent component) is exposed, and it is considered that liquid penetrates to some extent from this exposed portion. In addition, the water-repellent cellulose fibers themselves have lower rigidity than synthetic fibers, and tend to be deformed to some extent even in a non-swollen state. From the above, water-repellent cellulose fibers are more likely to be deformed by wiping pressure than synthetic fibers, and are presumed to improve the ability to collect dirt.

Furthermore, when water-repellent cellulose fibers are used, if the fibers are entangled and integrated by the action of a water-based fluid such as hydroentanglement or steam entanglement, the entanglement of the fibers progresses due to the water repellency of the water-repellent cellulose fibers. It is difficult and the fibers are entangled with a relatively high degree of freedom. In such a nonwoven fabric, the voids between the fibers are likely to be deformed by wiping pressure with or without deformation of the fibers. presumed to improve.

Furthermore, the present inventors have found that by appropriately selecting the amount of water-repellent cellulose fibers used, the amount of fluff coming off can be reduced, and the amount of fibers adhering to the object during wiping can be reduced. Since the water-repellent cellulose fibers themselves are difficult to entangle, they tend to fall off from the nonwoven fabric. , it is possible to make it difficult to cause falling off.

The use of water-repellent cellulose fibers is also preferable from the perspective of Sustainable Development Goals (SDGs). Cellulose fibers are biodegradable and attract attention as environmentally friendly materials. Therefore, according to the nonwoven fabric of the present disclosure, it is possible to provide a wiper that has excellent wiping performance and is easily accepted by consumers from the viewpoint of SDGs.

The use of a non-woven fabric using hydrophobic artificial cellulose fibers as a wet wipe applied to the human body as a sanitary product is described in Patent Document 2. is proposed to be shortened. Therefore, it is not designed in consideration of the sustained release of liquid when wiping a relatively large area such as a floor surface with a single wiper. , is not enough.
Hereinafter, embodiments of the nonwoven fabric for wipers according to the present disclosure will be described.

First, the fibers constituting the nonwoven fabric for wipers (hereinafter also simply referred to as "nonwoven fabric") according to the present disclosure will be described.

(water-repellent cellulose fiber)
Cellulose fibers are inherently hydrophilic, but in the present disclosure, cellulose fibers artificially imparted with water repellency are referred to as "water-repellent cellulose fibers".

The type of cellulose fiber is not particularly limited. Cellulose fibers include:
(1) Natural fibers derived from plants such as cotton, hemp, linen, ramie, jute, banana, bamboo, kenaf, shell ginger, hemp and kapok;
(2) solvent-spun cellulose fibers such as viscose-derived rayon and polynosic, cuprammonium-derived cupro, and solvent-spun Tencel® and lyocell, and other regenerated fibers;
(3) cellulose fibers obtained by melt spinning;
(4) semi-synthetic fibers such as acetate fibers; and (5) pulps such as mechanical, recycled and chemical pulps.

The water-repellent cellulose fibers may be obtained by attaching a water-repellent agent to these cellulose fibers to impart water repellency. Alternatively, the water-repellent cellulose fibers may be obtained by treating cellulose fibers having carboxyl groups and/or sulfonic acid groups with a treatment liquid containing an isocyanate-based compound and a non-fluorine-based water repellent. A water-repellent cellulose fiber obtained by such a method is disclosed, for example, in JP-A-2019-65443.

The water-repellent cellulose fibers preferably contain water-repellent rayon because the bending resistance of the nonwoven fabric tends to be low. Since rayon has a chrysanthemum-shaped cross-section, it is also preferable in that it tends to exhibit water repellency effectively. In addition, the chrysanthemum-shaped fiber cross section of rayon is observed as streaky unevenness extending in the length direction on the fiber surface. , allowing dirt to be trapped in the recess itself. Furthermore, since viscose rayon has a higher official moisture content and higher degree of secondary swelling than other cellulose fibers (e.g. cotton, lyocell), the surface is water repellent while the inside is hydrophilic and swellable. It is easier to give the effect of having (for example, deformation by wiping pressure when wet).

As water-repellent rayon, for example, Eco Repelace (trade name, water-repellent viscose rayon) manufactured by Daiwabo Rayon Co., Ltd., Olea (trade name, water-repellent viscose rayon) manufactured by Kelheim Fibers GmbH, and the like are marketed. In particular, Eco Repellent (trade name) exhibits high water repellency, has highly durable water repellency, and is preferably used because the water repellency does not easily decrease even when subjected to, for example, hydroentanglement treatment.

Alternatively, as the water-repellent cellulose fiber, a solvent-spun cellulose fiber such as lyocell with water repellency imparted thereto is preferably used because the decrease in strength of the fiber is small when wet. As a water-repellent solvent-spun cellulose fiber, for example, Lyocell Dry (trade name, water-repellent lyocell) manufactured by Lenzing Co., Ltd. is on the market.

The fineness of the water-repellent cellulose fibers may be 0.6 dtex or more, 1.0 dtex or more, or 1.4 dtex or more. The fineness of the water-repellent cellulose fibers may be 6.0 dtex or less, 5.0 dtex or less, or 3.0 dtex or less. In one aspect, the water-repellent cellulose fiber has a fineness of 0.6 dtex or more and 6.0 dtex or less. When the fineness of the water-repellent cellulose fibers is within the above range, appropriate voids are formed in the fiber layer A, and liquid is easily retained. The fineness of the water-repellent cellulose fiber is not limited to the above range. In particular, since it is difficult to adjust the fineness of natural fibers, cellulose fibers having a fineness outside the above range may be used. In general, pulp has a fineness of about 1.0 dtex or more and 4.0 dtex or less, and a fiber length of about 0.8 mm or more and 4.5 mm or less.

The fiber length of the water-repellent cellulose fiber is not particularly limited, and may be appropriately selected according to the material, the manufacturing method thereof, the manufacturing method of the fiber layer A, the manufacturing method of the nonwoven fabric, and the like. Water-repellent cellulose fibers are, for example, staple fibers. When the fiber layer A is made from a card web, the fiber length of the water-repellent cellulose fibers may be 100 mm or less, 75 mm or less, or 65 mm or less. The fiber length of the short water-repellent cellulose fibers may be 10 mm or more, 20 mm or more, or 30 mm or more. In the above case, in one aspect, the fiber length of the water-repellent cellulose fiber may be 10 mm or more and 100 mm or less. When the fiber layer A is produced from an airlaid web, the fiber length of the water-repellent cellulose fibers may be 2 mm or more and 20 mm or less.

In this embodiment, a plurality of water-repellent cellulose fibers having one or more different materials, fiber lengths, and finenesses may be used.

The water repellency of the fiber can be evaluated by the sedimentation velocity (6(1) f) measured by the following method according to the standard for medical gauze/medical absorbent cotton of Yakushokuki No. 0630001, for example.

For the fibers before manufacturing the nonwoven fabric or the fibers collected from the nonwoven fabric, wash and dry by a method of washing three times with warm water (40 ° C) for 2 minutes with the one in the state (initial) as it is, and then dried. Prepare a state (after washing) from which oil, etc., has been removed. Next, the fibers in each state are defibrated by a carding machine to prepare a fiber assembly. 0.3 g of this fiber aggregate is rolled into a ball with a diameter of 2 cm or less and gently dropped into water of 200 mm depth from a height of 12 mm above the water surface at a water temperature of 24 to 26°C. The initial sedimentation velocity and post-wash sedimentation velocity of the fiber are defined as the time from when the fiber assembly is dropped until it sinks under the water surface.

If the fibers cannot be defibrated by the carding machine (for example, if the fiber length is short), 0.3 g of the collected fibers may be rolled as they are and dropped into water. Alternatively, if the fibers are already in the form of a fiber assembly (for example, wet-laid nonwoven fabric or air-laid nonwoven fabric) and it is difficult to disentangle this with a carding machine, a piece of nonwoven fabric cut to a size of 1 cm × 1 cm 0 .3 g portions may be dropped into water.

The initial sedimentation rate of the water-repellent cellulose fibers is preferably 1 minute or longer, more preferably 5 minutes or longer, and particularly preferably 10 minutes or longer. In particular, it is preferable that at least a part of the water-repellent cellulose fibers does not settle under the water surface 10 minutes after the water-repellent cellulose fibers are dropped into the water. At this time, the water-repellent cellulose fibers may absorb water. In particular, cellulose fibers that are partly or wholly floating on the surface of the water after one minute has passed are particularly preferably used as water-repellent cellulose fibers. Similarly, the sedimentation rate of the water-repellent cellulose fibers after washing is preferably 1 minute or more, more preferably 5 minutes or more, and particularly preferably 10 minutes or more. However, the sedimentation velocity after washing may be outside this range as long as the initial sedimentation velocity satisfies the above range.

The surface of the water-repellent cellulose fiber is treated to be water-repellent, so that it exhibits water repellency and exhibits the sedimentation rate as described above. Therefore, the official moisture content of water-repellent cellulose fibers (especially water-repellent rayon) is equivalent to that of the same type of cellulose fibers that have not been treated for water repellency, and the degree of secondary swelling is inferior to that of cellulose fibers that have not been treated for water repellency. , tends to be higher than that of common synthetic fibers. For example, viscose rayon that has not been treated for water repellency has a secondary swelling degree (water swelling degree: measured according to JIS L1015:2010 8.26) of about 80% or more and 90% or less. Some have a degree of secondary swelling of about 45% to 55%. In addition, water-repellent rayon has an official moisture content (measured according to JIS L 1015) of about 10% to 13%. 11%).

(other fibers)
Other fibers that form the fiber layer A together with the water-repellent cellulose fibers are not particularly limited. Other fibers may be cellulose fibers that are not water-repellent but inherently hydrophilic (hereinafter referred to as "hydrophilic cellulose fibers" to distinguish them from water-repellent cellulose fibers), or synthetic or natural fibers. It's okay. Two or more types of fibers may be used as other fibers. Hydrophilic cellulose fibers and synthetic fibers are described below as examples of other fibers.

[Hydrophilic cellulose fiber]
As described above, hydrophilic cellulose fibers refer to cellulose fibers that are inherently hydrophilic without being imparted with water repellency. Accordingly, examples of hydrophilic cellulose fibers are as described for water-repellent cellulose fibers.

The hydrophilic cellulosic fibers may be regenerated fibers. Regenerated fibers are preferably used because the fineness can be easily adjusted and the variation is small. Among the regenerated fibers, viscose rayon is preferably used as a constituent fiber of the wiper nonwoven fabric because it has the characteristics described in relation to the water-repellent cellulose fibers. Also, the use of viscose rayon is cost effective.

The fineness of the hydrophilic cellulose fibers may be, for example, 0.2 dtex or more and 6.0 dtex or less, particularly 0.3 dtex or more and 4.5 dtex or less, and more particularly 0.4 dtex or more and 4.5 dtex or less. It may be 0 dtex or less, and more particularly 0.6 dtex or more and 3.0 dtex or less. If the fineness of the hydrophilic cellulose fibers is too small, fiber clumps (neps) are likely to occur in the nonwoven fabric, and if it is too large, the feel of the nonwoven fabric may deteriorate. The fineness of the hydrophilic cellulose fibers is not limited to these ranges. In particular, when using natural fibers, it is difficult to adjust the fineness, so fibers having a fineness outside the above range may be used.

The fiber length of the hydrophilic cellulose fibers contained in the fiber layer A is not particularly limited, and may be, for example, 10 mm or longer. A specific fiber length of the hydrophilic cellulose fibers contained in the fiber layer A may be selected according to the manufacturing method of the nonwoven fabric. The relationship between the nonwoven fabric manufacturing method (fiber layer manufacturing method) and the fiber length is as described in relation to the water-repellent cellulose fiber.

For the fiber layer A, a plurality of hydrophilic cellulose fibers different in one or more of the material, fiber length and fineness may be used.

The hydrophilic cellulose fibers may be such that the sample sinks below the water surface within 60 seconds when the sedimentation velocity is measured by the method described for evaluating the water repellency of water repellent cellulose fibers. The hydrophilic cellulose fibers may absorb water and sink below the surface of the water within, for example, 50 seconds, particularly within 45 seconds, more particularly within 30 seconds after the sample is dropped on the surface of the water in the beaker.

[Synthetic fiber]
Synthetic fibers include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof; polypropylene, polyethylene (high density polyethylene, low density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene copolymers (including propylene-ethylene copolymers and propylene-butene-1-ethylene copolymers), ethylene-vinyl polyolefin resins such as alcohol copolymers and ethylene-vinyl acetate copolymers; polyamide resins such as nylon 6, nylon 12 and nylon 66; acrylic resins; It may consist of one or more thermoplastic resins arbitrarily selected from plastics and elastomers thereof. Among these, biodegradable resins such as polylactic acid and polybutylene succinate are preferably used when SDGs are emphasized.

Alternatively, the synthetic fibers may be synthetic fibers comprising biomass feedstocks. Synthetic fibers containing biomass raw materials include, for example, biopolypropylene (also referred to as bioPP), biopolyethylene (also referred to as bioPE), biopolyethylene terephthalate (also referred to as bioPET), biopolytrimethylene terephthalate (also referred to as bioPTT), Bio polycarbonate (also called bio PC), bio polyurethane (also called bio PU), bio polyamide 11 (also called bio PA11), bio polyamide 1010 (also called bio PA1010), bio polyamide 610 (also called bio PA610), bio polyamide Synthetic fibers including MXD10 (also referred to as bio-MXD10), bio-polyamide 11T (also referred to as bio-PA11T), etc., more specifically, synthetic fibers produced by melt spinning such biomass raw materials. Synthetic fibers containing biomass raw materials are also preferably used when emphasizing SDGs.

Alternatively, the synthetic fibers may be synthetic fibers comprising recycled resin raw materials. Synthetic fibers containing recycled resin raw materials are, for example, recycled (regenerated) polypropylene (also referred to as recycled (regenerated) PP), recycled (regenerated) polyethylene terephthalate (also referred to as recycled (regenerated) PET), recycled (regenerated) nylon, and the like. . Synthetic fibers containing recycled resin raw materials are also preferably used when SDGs are emphasized.

In the following, when the resin is provided as a biomass raw material or a recycled resin raw material, the specifically indicated resin also refers to those raw materials. For example, polypropylene single fibers include single fibers made from ordinary polypropylene raw materials, single fibers made from bio-polypropylene, and recycled (regenerated) polypropylene single fibers.

Synthetic fibers can be monolithic fibers whose fiber cross section is made up of a single component (also called "single section") and/or composite fibers whose fiber cross section is made up of multiple components (also called "sections"). It may be a fiber. The conjugate fiber may be, for example, a concentric or eccentric core-sheath conjugate fiber, a sea-island conjugate fiber, a side-by-side conjugate fiber, or a split conjugate fiber. The cross-section of the fibers may be circular or non-circular, with non-circular shapes including elliptical, Y-shaped, X-shaped, I-shaped, multi-lobed, polygonal, star-shaped, and the like. The synthetic fibers may also have a hollow cross-section. In both the single fiber and the composite fiber, each section constituting the fiber may consist of one kind of resin, or two or more kinds of resins may be mixed.

When the synthetic fiber is a single fiber, the single fiber is made of one or more resins selected from the group consisting of the polyolefin resins, the polyester resins, the polyamide resins, and the acrylic resins. can be More specifically, a single polyethylene fiber, a single polypropylene fiber, a single polyethylene terephthalate fiber, or the like may be used.

When the synthetic fiber is a bicomponent fiber, two or more components may be arranged such that the lowest melting point thermoplastic constitutes a portion of the fiber surface. In that case, in the process of producing a non-woven fabric, when heat is applied under conditions where a component made of a thermoplastic resin with the lowest melting point (hereinafter referred to as "low melting point component") melts or softens, the low melting point component becomes an adhesive component. A combination of resins (first/second) constituting a conjugate fiber composed of a first component that is a thermoplastic resin with a higher melting point and a second component that is a thermoplastic resin with a lower melting point is, for example, polyethylene terephthalate /Polyethylene, polyethylene terephthalate/polypropylene, and polyethylene terephthalate/propylene copolymers, and combinations of polyester resins and polyolefin resins, and two types of polyolefins, such as polypropylene/polyethylene and polypropylene/propylene copolymers. A combination of plastic resins and a combination of two types of polyester resins having different melting points.

Alternatively, the combination of the first component and the second component may be a combination of biodegradable resins, and such a combination allows the proportion of biodegradable fibers in the fiber layer A to be increased. Specifically, by using polylactic acid as the first component and polybutylene succinate as the second component, the synthetic fiber can be made biodegradable.

The thermoplastic resin exemplified as the constituent component of the single fiber or composite fiber may contain other components as long as it contains 50% by mass or more of the specifically indicated thermoplastic resin. The specifically indicated thermoplastic resin may be contained in an amount of 80% by mass or more, or may be contained in an amount of 90% by mass or more, or the constituent component is substantially composed of the specifically indicated thermoplastic resin. good. Here, the term "substantially" is used in consideration of the fact that thermoplastic resins usually contain various additives and the like. For example, in the combination of polyethylene terephthalate/polyethylene, "polyethylene" may contain other thermoplastic resins and additives as long as it contains 50% by mass or more of polyethylene. This also applies in the following examples.

When the synthetic fiber is a concentric or eccentric core-sheath type composite fiber in which a thermoplastic resin having a higher melting point constitutes a core component as a first component and a thermoplastic resin having a lower melting point constitutes a sheath component as a second component. , core/sheath combinations include, for example, polypropylene/polyethylene, polypropylene/propylene-ethylene copolymer, polypropylene/propylene-butene-1-ethylene copolymer, polylactic acid/polybutylene succinate, polyethylene terephthalate/polyethylene, polyethylene Terephthalate/polypropylene, polyethylene terephthalate/propylene copolymer, polytrimethylene terephthalate/polyethylene, polybutylene terephthalate/polyethylene, polyethylene terephthalate/copolyester (eg polyethylene terephthalate copolymerized with isophthalic acid). Combinations of these resins may be used in splittable bicomponent fibers.

In the case of a core-sheath type composite fiber, the composite ratio of the core component to the sheath component (core component:sheath component) in volume ratio is preferably 80:20 to 20:80, preferably 70:30 to 30:70. is more preferred, and 60:40 to 40:60 is even more preferred.

In the case of splittable conjugate fibers, the volume ratio of the two components (first:second) is preferably 80:20 to 20:80, more preferably 70:30 to 30:70. , 60:40 to 40:60. In the case of splittable conjugate fibers, the number of divisions (that is, the number of sections in the conjugate fiber) may be, for example, 4 or more and 32 or less, particularly 4 or more and 20 or less, more particularly 6 or more, It may be 10 or less.

In this embodiment, the combination of the first component/second component is polylactic acid/polybutylene succinate, polyethylene terephthalate/copolyester, polypropylene/polyethylene, polyethylene terephthalate/polyethylene, core-sheath type composite fiber (concentric or eccentric) can be preferably used as a synthetic fiber. When these fibers are used as adhesive fibers, they exhibit adhesiveness at a relatively low temperature (110° C. or higher and 130° C. or lower) and soften the texture of the nonwoven fabric after bonding.

The fineness of the synthetic fiber may be, for example, 1.0 dtex or more and 8.0 dtex or less, particularly 1.5 dtex or more and 7.5 dtex or less, more particularly 1.6 dtex or more and 6.0 dtex or less, still more particularly may be greater than or equal to 1.7 dtex and less than or equal to 5.0 dtex. If the fineness of the synthetic fiber is too small, the strength of the nonwoven fabric is low and the nonwoven fabric tends to stretch easily. It may reduce sexuality. If the fineness of the synthetic fiber is too large, the feel of the nonwoven fabric may become hard. If the nonwoven fabric tends to stretch, for example, when the nonwoven fabric is attached to a jig for wiping, slack or wrinkles may occur when the nonwoven fabric is attached to the jig, and the fiber density on the surface of the nonwoven fabric may become low. Therefore, dirt that has been collected once may fall off.

In particular, when the synthetic fiber is a splittable conjugate fiber, the splittable conjugate fiber may have a fineness of 1.0 dtex or more and 4.0 dtex or less before splitting, and gives a synthetic fiber of 0.1 dtex or more and less than 1.0 dtex after splitting. can be anything.

The fiber length of the synthetic fiber is not particularly limited, and may be appropriately selected according to the manufacturing method of the nonwoven fabric. For example, if the fibrous layer A is produced by making a carded web in the production of a nonwoven fabric, the synthetic fibers may be staple fibers. The fiber length of the short fibers may be, for example, 10 mm or more and 100 mm or less, particularly 20 mm or more and 75 mm or less, and more particularly 30 mm or more and 65 mm or less. Alternatively, when the fiber layer A is manufactured by the air laying method, the fiber length may be, for example, 2 mm or more and 20 mm or less.

Synthetic fibers are generally hydrophobic, eg those having a nominal moisture content of less than 5%. In this embodiment, the synthetic fiber may be one that has undergone a hydrophilic treatment. Hydrophilization treatment includes, for example, corona discharge treatment, sulfonation treatment, graft polymerization treatment, kneading of a hydrophilizing agent into fibers, and application of a durable oil.

In the above, hydrophilic cellulose fibers and synthetic fibers have been described as other fibers, but other fibers are not limited to these. Other fibers may include, for example, silk and natural fibers such as wool.

(Fibers constituting fiber layers other than fiber layer A)
This embodiment is a nonwoven fabric including a fiber layer A containing water-repellent cellulose fibers in a predetermined proportion, and the fiber layer A forms at least one surface of the nonwoven fabric. Therefore, the nonwoven fabric of this embodiment may contain fiber layers other than the fiber layer A, as described later. The fibers constituting the fiber layers other than the fiber layer A are not particularly limited, and may be one or more fibers selected from the above-described water-repellent cellulose fibers, hydrophilic cellulose fibers, synthetic fibers and natural fibers. .

When the fiber layer other than the fiber layer A is an intermediate fiber layer positioned between two fiber layers A, the fibers constituting the intermediate fiber layer may be hydrophilic cellulose fibers having a fiber length of less than 10 mm. . Since the intermediate fiber layer contains at least a predetermined proportion of short hydrophilic cellulose fibers, when the nonwoven fabric is used as a wet wiper, the intermediate fiber layer plays a "tank-like" role to retain liquid, and the use of the fiber layer A and Together, it makes it possible to release the liquid little by little over a long period of time. Examples of hydrophilic cellulose fibers having a fiber length of less than 10 mm include pulps such as mechanical pulp, regenerated pulp and chemical pulp. There are spun cellulose fibers and semi-synthetic fibers.

In this embodiment, pulp is preferably used as the hydrophilic cellulose fibers contained in the intermediate fiber layer. The pulp may be conventionally produced from softwood or hardwood. In general, pulp fibers have a fineness of about 1.0 dtex to 4.0 dtex and a fiber length of about 0.8 mm to 4.5 mm.

Since pulp has a track record of being used as a material for sanitary products, it is easily accepted by consumers, and since it is biodegradable, it is preferably used as a material for composing disposable wipers that are discarded after use. Furthermore, pulp made from wood promotes entangling of fibers when hydrophilic cellulose fibers are contained in the fiber layer A when a nonwoven fabric is produced by a hydroentangling method as described later.

Alternatively, the fiber layers other than the fiber layer A may be mesh sheets as described later. When the mesh sheet is included as a fiber layer other than the fiber layer A, the fibers constituting the fiber layer are monofilaments made of synthetic resin, strands made by twisting fibers, or undrawn or drawn filaments obtained by extrusion molding. It is a net (or a filament-like material extruded into a net shape).

Alternatively, the fiber layer other than the fiber layer A may be a meltblown nonwoven fabric, a long fiber nonwoven fabric (also referred to as a spunbond nonwoven fabric), as described later, an air-through nonwoven fabric formed from short fibers, a point-bonded nonwoven fabric, or a wet-laid nonwoven fabric. It's okay. When these nonwoven fabrics are included as a fiber layer other than the fiber layer A, the fibers constituting the fiber layer are synthetic fibers or regenerated fibers.

(Configuration of nonwoven fabric)
Next, the structure of the nonwoven fabric of this embodiment will be described. The nonwoven fabric of the present embodiment is a nonwoven fabric having a first surface and a second surface on the opposite side, and contains water-repellent cellulose fibers at a rate of 10% by mass or more and less than 75% by mass based on the total mass of the nonwoven fabric. , containing other fibers in a proportion of more than 25% by mass and not more than 90% by mass,
At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fibers at a ratio of 10% by mass or more and the other fibers at a ratio of 90% by mass or less,
The fibers are integrated by entangling with each other.

The nonwoven fabric of this embodiment is configured such that the surface of the fiber layer A containing a predetermined proportion of water-repellent cellulose fibers is at least one of the two main surfaces of the nonwoven fabric, that is, the first surface and the second surface. This ensures excellent sustained liquid release and dirt trapping.

The proportion of the water-repellent cellulose fibers contained in the fiber layer A is 10 mass % or more, particularly 30 mass % or more and 90 mass % or less, more particularly 40 mass % or more and 80 mass % or less. As described above, the water-repellent cellulose fiber absorbs liquid from the cut surface and swells, and due to the swelling, the rigidity is lowered, and deformation due to wiping pressure is more likely to occur than the synthetic fiber. In addition, when the fibers are entangled with each other by a high-pressure fluid flow (especially a high-pressure water flow) as described later, the water-repellent cellulose fiber has a water-repellent fiber surface, so that the entanglement can be prevented from progressing excessively. It is easy to form moderate voids between fibers. Therefore, by placing the water-repellent cellulose fiber on the wiper's wiping surface, the deformation of the fiber makes it easier to collect solid dirt with a slightly larger size. and can be released gradually.

If the ratio of the water-repellent cellulose fibers contained in the fiber layer A is less than 10% by mass, the dirt trapping property and the sustained liquid release property may become insufficient.
The ratio of the water-repellent cellulose fibers contained in the fiber layer A may be 100% by mass, that is, the fiber layer A may be composed only of the water-repellent cellulose fibers. However, the higher the proportion of the water-repellent cellulose fibers contained in the fiber layer A, the higher the water repellency of the fibers and the more difficult the entanglement by the high-pressure liquid flow proceeds, and the strength of the fibers themselves is not as great as that of the synthetic fibers. As a result, the strength of the nonwoven fabric may decrease, or fluff may easily come off during wiping.

The fiber layer A contains fibers other than the water-repellent cellulose fibers as the remainder. Therefore, the proportion of other fibers is 90% by mass or less. Other fibers are not particularly limited, and may be synthetic fibers or hydrophilic cellulose fibers. Alternatively, other fibers may include both synthetic fibers and hydrophilic cellulosic fibers.

Synthetic fibers are preferably used because they improve the mechanical strength of the nonwoven fabric and impart rigidity to the nonwoven fabric. In addition, when synthetic fibers are used as adhesive fibers and some of the constituent components are melted or softened to bond the fibers together, the mechanical strength of the nonwoven fabric is further improved, the dimensional stability is improved, and the surface is fluffed. is also more suppressed. In addition, synthetic fibers are generally hydrophobic and, together with water-repellent cellulose fibers, form adequate inter-fiber voids in the nonwoven fabric to allow adequate liquid retention and gradual release.

When the fiber layer A contains synthetic fibers as other fibers, the proportion of the synthetic fibers in the fiber layer A may be more than 0% by mass and 35% by mass or less, particularly 5% by mass or more and 30% by mass or less, and more In particular, it may be 10% by mass or more and 25% by mass or less. If the proportion of the synthetic fibers exceeds 35% by mass, the proportion of the water-repellent cellulose fibers is correspondingly reduced, making it difficult to obtain the effects of containing the water-repellent cellulose fibers (especially, the improvement of the dirt-collecting property). In addition, when the ratio of synthetic fibers increases, the entanglement of the fibers becomes insufficient when the fibers are entangled with a high-pressure fluid flow, and the voids between the fibers in the nonwoven fabric may become excessively large. The liquid retained in such large inter-fiber voids is likely to be released once by wiping pressure, so if the ratio of synthetic fibers is too large, the nonwoven fabric may deteriorate in the sustained release of liquid.

If the fiber layer A contains two or more types of synthetic fibers, at least one type of synthetic fiber may be used as adhesive fibers and at least one type of synthetic fiber may be present as non-adhesive fibers. Here, the non-adhesive fiber does not melt or soften at the temperature at which the adhesive component of the adhesive fiber melts or softens to bond the fibers together, and retains its fiber shape. Therefore, whether it is an adhesive fiber or a non-adhesive fiber is determined by the resin constituting each fiber and the conditions (heating temperature) in manufacturing the nonwoven fabric. For example, a synthetic fiber containing polyethylene as one component is subjected to heat treatment at about 135 ° C. and used as an adhesive fiber containing polyethylene as an adhesive component, and a single synthetic fiber made of polypropylene or polyethylene terephthalate is used as a non-adhesive fiber. may be used.

By using both adhesive fibers and non-adhesive fibers, the non-adhesive fibers are included in the nonwoven fabric while maintaining the shape of the fibers. Since non-adhesive fibers, which are synthetic fibers, are generally hydrophobic as described above, entangling does not progress easily even when subjected to entangling treatment using a water-based fluid, and they exist in the nonwoven fabric in a state with a relatively high degree of freedom. . Therefore, compared with the case where only adhesive fibers are used, there is a tendency for the dirt collecting property to be improved. In addition, bonding of fibers by adhesive fibers tends to inhibit deformation of the fibers and inter-fiber voids due to wiping pressure. Furthermore, even when the non-woven fabric is impregnated with a liquid, the non-adhesive fibers are less likely to absorb the liquid and less likely to cause a decrease in fiber strength due to liquid absorption or swelling unlike cellulose fibers. Therefore, the non-adhesive fibers contribute to maintaining the strength and bulkiness of the nonwoven fabric even in a wet state, and can provide a wet wiper with excellent dirt collecting properties and usability.

As described above, when the synthetic fiber is included in the fiber layer A, the synthetic fiber is one or more synthetic fibers selected from synthetic fibers containing biomass raw materials, biodegradable synthetic fibers, and synthetic fibers containing recycled raw materials. It may be a fiber. Such synthetic fibers are preferably used together with water-repellent cellulose fibers from the viewpoint of SDGs.

When hydrophilic cellulose fibers are included as other fibers, the hydrophilic cellulose fibers themselves are absorbent, allowing the fibers to store liquid and release it in the early stages of the wiping process. The use of hydrophilic cellulose fibers is therefore useful in applications where it is desirable to perform wiping with a relatively large release of liquid in the initial stages of wiping (e.g., it is desirable to first "loosen" stubborn dirt with liquid). applications). In addition, hydrophilic cellulose fibers exhibit excellent entangling properties when the fibers are entangled with each other with a high-pressure fluid flow. Therefore, by using hydrophilic cellulose fibers, it is possible to increase the degree of entanglement between fibers, improve the strength of the nonwoven fabric, and/or prevent fluffing and fluffing. In particular, when the nonwoven fabric of the present embodiment does not contain a fiber layer other than the fiber layer A and the fibers are entangled with a high-pressure fluid flow, the hydrophilic cellulose fibers are mixed with other fibers in order to ensure the entanglement of the fibers. It is preferable to include as

When the fiber layer A contains hydrophilic cellulose fibers as other fibers, the proportion of the hydrophilic cellulose fibers in the fiber layer A may be more than 0% by mass and 75% by mass or less, particularly 10% by mass or more and 60% by mass. % or less, more particularly 20 mass % or more and 50 mass % or less. Hydrophilic cellulose fibers, like water-repellent cellulose fibers, have swelling properties and are easily deformed by wiping pressure when non-woven fabrics are used as wet wipes. The trapping property of is not lowered so much. However, when the proportion of hydrophilic cellulose exceeds 75% by mass, the liquid retained in the hydrophilic cellulose fibers is released at once at the start of the wiping operation, and the surface to be wiped becomes excessively wet, making it difficult to perform wiping smoothly. be.

The fibrous layer A may contain both hydrophilic cellulose fibers and synthetic fibers as other fibers. In that case, the ratio of the hydrophilic cellulose fiber in the fiber layer A is 0% by mass to 75% by mass, particularly 10% by mass to 60% by mass, and the ratio of the synthetic fiber in the fiber layer A is 0% by mass to 30% by mass. % or less, particularly 5 mass % or more and 25 mass % or less. When hydrophilic cellulose fibers and synthetic fibers are contained within this range, the mechanical strength of the nonwoven fabric can be increased while the nonwoven fabric retains an appropriate amount of liquid, and the amount of fluff coming off during wiping can be suppressed.

The nonwoven fabric of this embodiment may have a single-layer structure consisting of the fiber layer A only, or may have a laminated structure consisting of the fiber layer A and one or more other fiber layers A. The other fiber layer is a fiber layer made of fibers other than water-repellent cellulose, or a fiber layer in which the ratio of the water-repellent cellulose fiber layer is outside the above range. The other fiber layer may be, for example, a meltblown nonwoven fabric, a long-fiber nonwoven fabric (also referred to as a spunbond nonwoven fabric), an air-through nonwoven fabric formed from short fibers, a point-bonded nonwoven fabric, or a wet-laid nonwoven fabric.

Alternatively, the other fibrous layer may be a mesh sheet. Reticulated sheets include scrims, nets made by biaxially stretching thermoplastic resins, and the like. As the mesh sheet, for example, CONWED NET (registered trademark) manufactured by CONWED GLOBAL NETTING SOLUTIONS in the United States may be used. Since the mesh sheet tends to exhibit high mechanical properties while having relatively large voids, it is well integrated with the fiber layer A and serves to reinforce the nonwoven fabric. Further, by using a mesh sheet, when the fibers are entangled with a high-pressure fluid flow, the pressure of the liquid flow can be lowered to integrate the fiber layers.

Regardless of whether it is a single layer or a laminate, the nonwoven fabric of the present embodiment contains water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, based on the total mass of the nonwoven fabric, and other fibers. It is contained in a ratio of more than 25% by mass and 90% by mass or less. If the ratio of the water-repellent cellulose fibers to the entire nonwoven fabric is less than 10% by mass, the fiber layer A cannot be formed, or the ratio of the fiber layer A to the entire nonwoven fabric becomes too small, resulting in poor dirt-collecting properties. And the sustained release properties of liquids tend to decrease. If the water-repellent cellulose fibers account for 75% by mass or more of the entire nonwoven fabric, the strength of the nonwoven fabric may decrease and/or the surface of the nonwoven fabric may become fuzzy. The ratio of the water-repellent cellulose fibers in the entire nonwoven fabric may be particularly 10% by mass or more and 70% by mass or less, more particularly 20% by mass or more and 60% by mass or less.

When the nonwoven fabric of this embodiment has a laminated structure, the proportion of the water-repellent cellulose fibers in the entire nonwoven fabric may be determined according to the configuration of the other fiber layers and the laminated structure. For example, as described below, the nonwoven fabric of the present embodiment has a first fiber layer, a second fiber layer, and an intermediate fiber layer disposed between the first and second fiber layers, A configuration in which the fiber layer and the second fiber layer are both the fiber layer A is assumed. In this structure, if the intermediate fiber layer contains hydrophilic fibers, etc., so that it easily retains water and does not easily release water even when a wiping pressure is applied, the ratio of the water-repellent cellulose fibers should be reduced. can be done. On the other hand, if the intermediate fiber layer is extremely thin or contains large voids (for example, a mesh sheet or a non-woven fabric in which fibers are bonded together), the proportion of water-repellent cellulose fibers may be increased. As a result, the intermediate fiber layer cannot hold the liquid when the wiping pressure is applied, and the liquid that has moved to the first fiber layer and the second fiber layer is prevented from moving to the nonwoven fabric surface by the water-repellent cellulose fibers. , may prevent excessive release of liquid.

More specifically, when the intermediate fiber layer is a wet-laid nonwoven fabric containing hydrophilic cellulose fibers, the proportion of the water-repellent cellulose fibers in the entire nonwoven fabric is 10% by mass or more and 75% by mass or less, particularly 10% by mass or more and 70% by mass. Below, more particularly, it may be 20% by mass or more and 60% by mass or less. When the intermediate fiber layer is a nonwoven fabric in which the fibers are bonded to each other (for example, an air-through nonwoven fabric) containing synthetic fibers, the proportion of water-repellent cellulose fibers in the entire nonwoven fabric is 15% by mass or more and 75% by mass or less, particularly 25% by mass. 70% by mass or less, more particularly 30% by mass or more and 65% by mass or less. When the intermediate fiber layer is a mesh sheet, the ratio of the water-repellent cellulose fibers in the entire nonwoven fabric is 15% by mass or more and 75% by mass or less, particularly 25% by mass or more and 70% by mass or less, more particularly 30% by mass or more and 65% by mass. It can be:

When the nonwoven fabric of this embodiment has a laminated structure, it has a first fiber layer, a second fiber layer, and an intermediate fiber layer disposed between the first and second fiber layers, Both the fiber layer and the second fiber layer may be the fiber layer A. A nonwoven fabric of such construction allows both surfaces to be used as wiping surfaces that exhibit excellent wiping performance. In addition, by appropriately selecting the configuration of the intermediate fiber layer, it is possible to adjust the liquid holding capacity and mechanical properties of the entire nonwoven fabric.

The intermediate fiber layer may be, for example, one or more selected from air-through nonwovens and point-bonded nonwovens formed by staple fibers, as well as meltblown nonwovens, long fiber nonwovens, wet-laid nonwovens, and mesh sheets. When the intermediate fiber layer is an air-through nonwoven fabric, the air-through nonwoven fabric may be made of, for example, synthetic fibers having a fineness of 1.0 dtex or more and 8.0 dtex or less, particularly 1.5 dtex or more and 6.0 dtex or less. When the intermediate fiber layer is a meltblown nonwoven fabric, the meltblown nonwoven fabric may be made of synthetic fibers having a fineness of 0.005 dtex or more and 1.0 dtex or less, particularly 0.007 dtex or more and 0.7 dtex or less, for example. When the intermediate layer is a long-fiber nonwoven fabric, the long-fiber nonwoven fabric may be made of synthetic fibers having a fineness of, for example, 0.5 dtex or more and 7.0 dtex or less, particularly 1.0 dtex or more and 4.0 dtex or less.

The long-fiber nonwoven fabric includes two or more types of spunbond nonwoven fabric, a composite sheet of a sheet in which threads are aligned in the longitudinal direction and a sheet in which threads are aligned in the horizontal direction, and a net-like web formed by splitting and stretching a film. It may be a sheet or the like that is laminated and integrated. As such a sheet, for example, Milife (registered trademark) manufactured by JX ANCI Corporation, Warif (registered trademark) manufactured by JX ANCI Corporation, or the like may be used.

In this embodiment, the intermediate layer may be a wet-laid nonwoven comprising hydrophilic cellulose fibers, in particular a wet-laid nonwoven (or tissue) made of pulp. Wet-laid nonwoven fabrics containing hydrophilic cellulose fibers are highly absorbent and can hold a large amount of liquid. When used as a wiping surface, it can function to supply the liquid to the wiping surface for a long period of time during the wiping operation. In addition, when the fibers are entangled with a high-pressure liquid flow, the hydrophilic cellulose fibers are positioned between the two fiber layers A, so that they are well entangled with the fibers constituting the fiber layers A, and the strength of the entire nonwoven fabric is improved. can improve

Alternatively, the intermediate fibrous layer may be a mesh sheet. As described above, the net-like sheet can reduce the influence on the entanglement of fibers and reinforce the entire nonwoven fabric satisfactorily. Therefore, for example, if hydrophilic cellulose fibers are contained in the first fiber layer and/or the second fiber layer, when the fibers are entangled with each other by a high-pressure fluid flow, the hydrophilic cellulose fibers pass through the meshes of the mesh sheet. Because it promotes entanglement, the mechanical properties of the nonwoven can be improved.

If the reticulated sheet has regular openings (for example rectangles or squares defined by filaments), the dimensions of the openings may for example be 3 mm or more, especially 4 mm or more, more especially 5 mm. or more. The upper limit of the dimensions of the opening may be, for example, 15 mm, especially 12 mm. The dimension of the opening is the length of the longest line segment among the line segments connecting any two points of the contour defining the opening. If the dimensions of the openings are too small, the entanglement of the upper and lower fiber layers may become insufficient, especially when the nonwoven fabric is structured such that the first fiber layer and the second fiber layer are arranged above and below the mesh sheet. . As a result, delamination may easily occur. The reticulated sheet having regular openings may have an open area ratio of 50% to 99%, particularly 60% to 98%, more particularly 70% to 97%. When the open area ratio is within this range, the entanglement property with the fibers tends to be improved, and when the fiber layers are located on both sides, it is easy to ensure good entanglement of the fibers between the fiber layers.

Both the first fiber layer and the second fiber layer may be the fiber layer A. Therefore, both fiber layers have different types of fibers, a mixing ratio of fibers, a basis weight, a manufacturing form of the fiber layer (type of fiber web), etc. They may be the same or different. For example, by varying the proportion of water-repellent cellulose fibers between the two fiber layers, the surfaces of the two fiber layers can be used for different purposes (e.g., wiping dining room floors and wiping bathroom floors). may be used.

In the nonwoven fabric of the present embodiment, the fiber layer A may have a basis weight of, for example, 35 g/m ² or more and 100 g/m ² or less, particularly 40 g/m ² or more and 95 g/m ² or less. It may more particularly have a basis weight of 45 g/m ² or more and 90 g/m ² or less, and still more particularly may have a basis weight of 50 g/m ² or more and 85 g/m ² or less.

When the fiber layer A exists as the first fiber layer and the second fiber layer, each of the first fiber layer and the second fiber layer may have a basis weight of, for example, 10 g/m ² or more and 50 g/m ² or less. It may have a basis weight of 12.5 g/m ² or more and 47.5 g/m ² or less, more particularly 15 g/m ² or more and 45 g/m ² or less, still more particularly 17.5 g /m ² or more and 40 g/m ² or less.

In addition, the intermediate fiber layer that forms the nonwoven fabric together with the first and second fiber layers may have a basis weight of, for example, 5 g/m ² or more and 50 g/m ² or less, particularly 6 g/m ² or more and 45 g/m ² or less. It may have a basis weight, more particularly it may have a basis weight of 7 g/m ² or more and 40 g/m ² or less, and even more particularly it may have a basis weight of 8 g/m ² or more and 35 g/m ² or less.

In a nonwoven fabric having a configuration including first and second fiber layers and an intermediate fiber layer, when the weight of the entire nonwoven fabric is set to 1, the ratio of the weight of the intermediate fiber layer to this (intermediate fiber layer/entire nonwoven fabric) is, for example, It may be 0.05 or more and 1 or less, particularly 0.10 or more and 0.80 or less, more particularly 0.15 or more and 0.60 or less. If the ratio of the intermediate fiber layer to the nonwoven fabric is too large, the effect of the fiber layer A may not be obtained, and the function of the intermediate fiber layer may be excessively exhibited, resulting in excessive rigidity of the nonwoven fabric (intermediate fiber When the layer is a mesh sheet), or the liquid is likely to be released at once, and the sustained release property is lowered (when the intermediate fiber layer is made of hydrophilic cellulose fibers). On the other hand, if the weight ratio of the intermediate fiber layer is too small, the effect of providing the intermediate fiber layer may not be sufficiently obtained.

The basis weight of the entire nonwoven fabric of this embodiment may be appropriately selected according to the application. The nonwoven fabric of the present embodiment as a whole may have a basis weight of, for example, 30 g/m ² or more and 100 g/m ² or less, particularly 35 g/m ² or more and 95 g/m ² or less, more particularly It may have a basis weight of 40 g/m ² or more and 90 g/m ² or less, even more particularly 45 g/m ² or more and 85 g/m ^{2 or} less.

The nonwoven fabric of the present embodiment may have a dry tensile strength in the MD direction of, for example, 30 N/5 cm or more and 200 N/5 cm or less, particularly 35 N/5 cm or more and 195 N/5 cm or less, more particularly It may be 40 N/5 cm or more and 190 N/5 cm or less. If the dry tensile strength in the MD direction is too low, the product may break during processing. If the dry tensile strength in the MD direction is too high, the nonwoven fabric tends to be rigid. If a rigid nonwoven fabric is used as a wiper, the object may be damaged.

The nonwoven fabric of the present embodiment may have a dry tensile strength in the CD direction of, for example, 3 N/5 cm or more and 100 N/5 cm or less, particularly 4 N/5 cm or more and 95 N/5 cm or less, more particularly It may be 5 N/5 cm or more and 90 N/5 cm or less. If the dry tensile strength in the CD direction is too low, it may break during use. If the dry tensile strength in the CD direction is too high, the nonwoven fabric tends to be rigid. If a rigid nonwoven fabric is used as a wiper, the object may be damaged.

The nonwoven fabric of the present embodiment may have a dry elongation in the MD direction of, for example, 20% or more and 100% or less, particularly 25% or more and 95% or less, more particularly 30% or more and 90%. may be: In addition, the nonwoven fabric of the present embodiment may have a dry elongation percentage in the CD direction of, for example, 10% or more and 200% or less, particularly 15% or more and 195% or less, and more particularly 20% or more. It may be 190% or less. If the dry elongation in the MD or CD direction is too low, the nonwoven fabric may break at the slightest deformation and may be less flexible during fixture mounting. If the elongation in the MD or CD direction during drying is too high, it becomes difficult to handle during product processing.

In the nonwoven fabric of the present embodiment, the stress at 10% elongation in the MD direction when dry may be, for example, 3 N/5 cm or more and 60 N/5 cm or less, particularly 4 N/5 cm or more and 55 N/5 cm or less. In particular, it may be 5 N/5 cm or more and 60 N/5 cm or less. In addition, the nonwoven fabric of the present embodiment may have a stress at 10% elongation in the CD direction when dried, for example, 0.5 N/5 cm or more and 30 N/5 cm or less, particularly 0.6 N/5 cm or more and 25 N/5 cm or less. and more particularly 0.7 N/5 cm or more and 20 N/5 cm or less. If the stress at 10% elongation in the MD direction or CD direction when dry is too low, it becomes difficult to handle during product processing. If the stress at 10% elongation in the MD or CD direction during drying is too high, the fibers tend to be difficult to move during the wiping operation, which may reduce the ability to collect dirt.

(Method for manufacturing nonwoven fabric)
Next, a method for manufacturing the nonwoven fabric of this embodiment will be described.
The laminated nonwoven fabric of the present embodiment is, for example,
Producing a fibrous web A containing water-repellent cellulose fibers in a proportion of 10% by mass or more and containing other fibers in a proportion of 90% by mass or less, and, if necessary, a fibrous web other than the fibrous web A (convenient , making a "fiber web B"),
laminating a fibrous web A and a fibrous web B to produce a laminated fibrous web; and subjecting the laminated fibrous web to a treatment to entangle the fibers;
In producing the fibrous web A and the fibrous web B, based on the total mass of the laminated fibrous web, the proportion of water-repellent cellulose fibers is 10% by mass or more and 75% by mass or less, and the proportion of other fibers is more than 25% by mass and 90% by mass. % or less, selecting the type and ratio of the fibers that make up each fiber web, and the basis weight of each fiber web,
It can be manufactured by a manufacturing method. When the fibrous web B is not produced (that is, when a nonwoven fabric having a single-layer structure is produced), the fibrous web A contains water-repellent cellulose fibers at a rate of 10% by mass or more and less than 75% by mass, and other fibers. It is manufactured as containing at a ratio of more than 25% by mass and 90% by mass or less.

The fibrous webs A may be laminated such that two fibrous webs A ("fibrous web A1", "fibrous web A2") are made and the fibrous web B is positioned between the two fibrous webs. . By subjecting such a laminated web to a treatment for entangling the fibers, a nonwoven fabric having a structure in which an intermediate fiber layer is positioned between the first fiber layer and the second fiber layer as the fiber layer A is obtained.

The types and weight per unit area of the fibers contained in the fiber webs A, A1 and A2 and the fiber web B are as described in relation to the fiber layer A, the first fiber layer and the second fiber layer, and are omitted here. . The types and weight per unit area of the fibers contained in the fiber web B are as described in relation to the other fiber layers and the intermediate fiber layer, and are omitted here.

The fibrous webs A, A1 and A2 can be produced by known methods. The form of each fiber web may be selected from, for example, card webs such as parallel webs, cross webs, semi-random webs and random webs, airlaid webs, wet papermaking webs, and the like. When producing the fibrous web A1 and the fibrous web A2, these morphologies can differ from each other. If the fibrous webs A1 and A2 are carded webs, it is easy to obtain a nonwoven fabric suitable for wiper applications having inter-fiber voids suitable for collecting dirt.

The form of the fibrous web B is also not limited and may be any of the forms exemplified above in relation to the fibrous webs A, A1 and A2. When the fibrous web B is composed of pulp, the fibrous web B may be a wet papermaking web or an airlaid web. As the fibrous web B, for example, one provided (for example, sold) as a wet papermaking nonwoven fabric, a meltblown nonwoven fabric, or a long fiber nonwoven fabric may be used. In this case, strictly speaking, the fibrous web B is not a web state in which the degree of entanglement between fibers is small, but a nonwoven fabric in which the fibers are integrated. Alternatively, as the fiber web B, a mesh sheet may be used. Again, strictly speaking, the fiber web B is not in the form of a web.

The laminated fibrous web or fibrous web A is subjected to a treatment to entangle the fibers. The treatment for entangling the fibers is, for example, a needle punching treatment or a high-pressure fluid flow (especially water flow) entangling treatment. In high-pressure fluid flow processing, high-pressure fluids are, for example, high-pressure gases such as compressed air, high-pressure liquids such as high-pressure water, and high-pressure steam. In the production of non-woven fabrics, hydroentanglement treatment using high-pressure water as a high-pressure fluid is often used, and in the present embodiment as well, hydroentanglement treatment is preferably used from the viewpoint of ease of implementation. In the following, the entangling process when using high-pressure water (hereinafter also simply referred to as "water flow") as the high-pressure fluid will be described.

In high pressure fluid flow processing, the high pressure fluid is, for example, a high pressure gas such as compressed air and a high pressure liquid such as high pressure water. In the production of non-woven fabrics, hydroentanglement treatment using high-pressure water as a high-pressure fluid is often used, and in the present embodiment as well, hydroentanglement treatment is preferably used from the viewpoint of ease of implementation. In the following, a manufacturing method using high-pressure water (hereinafter also simply referred to as “water flow”) as the high-pressure fluid will be described.

The hydroentangling treatment is carried out by placing the laminated fiber web or fiber web A on a support and jetting a columnar water jet. For example, the support is preferably a plain weave support of 80 mesh or more and 100 mesh or less. In the hydroentangling treatment, a water flow with a water pressure of 1 MPa or more and 15 MPa or less is applied from a nozzle having orifices with a hole diameter of 0.05 mm or more and 0.5 mm or less at intervals of 0.3 mm or more and 1.5 mm or less to the laminated fiber web. It may be carried out by spraying 1 to 5 times on each of the front and back surfaces. The water pressure is preferably 1 MPa or more and 10 MPa or less, more preferably 1 MPa or more and 7 MPa or less.

Entangling by the hydroentangling process proceeds more easily as the hydrophilicity of the fibers is higher, and when a fibrous web consisting only of hydrophilic fibers is subjected to the hydroentangling process, a nonwoven fabric with a high fiber density in which the fibers are closely entangled can be obtained. There is a tendency. In the present embodiment, water-repellent cellulose fibers are included in the fiber web, and the water-repellent cellulose fibers are difficult to entangle by hydroentangling treatment. It tends to give a nonwoven fabric with large voids and a relatively large degree of fiber freedom. As a result, when the obtained nonwoven fabric is used as a wiper, the water-repellent cellulose fibers themselves are easily deformed, and together with this, the wiped dirt is easily retained in the wiper. In addition, the inter-fiber voids formed by the water-repellent cellulose fibers are suitable for accumulating and appropriately releasing liquid.

If any one or more of the fibrous webs contain adhesive fibers, the laminated fibrous web or fibrous web A may be subjected to a bonding treatment to provide a bonded fiber-to-fiber configuration in the resulting nonwoven. The bonding process may be a thermal bonding process, or may be bonding by electron beam irradiation, or ultrasonic welding. According to the heat treatment, the adhesive fibers (for example, the low melting point component of the composite fiber) are melted or softened by heating during the heat treatment, and the fibers constituting the laminated fiber web or the fiber web A can be bonded together.

The heat treatment is, for example, hot air processing by blowing hot air, hot roll processing (hot embossing roll processing), or heat treatment using infrared rays. The hot air processing treatment may be performed using a device that blows hot air at a predetermined temperature onto the laminated fiber web, such as a hot air penetration type heat treatment machine or a hot air blowing type heat treatment machine.

The heat treatment temperature (for example, the temperature of hot air) may be a temperature at which the component that constitutes the adhesive fiber and functions as an adhesive component softens or melts. For example, the heat treatment temperature may be a temperature above the melting point of the component. For example, when the adhesive fiber contains polyethylene as a component and polyethylene is used as the adhesive component, the heat treatment temperature may be 130 ° C. to 150 ° C., and when polybutylene succinate is used as the adhesive component, the heat treatment temperature is 120. °C to 133 °C.

(wiper)
The laminated nonwoven fabric of this embodiment is suitable for use as a wiper. The nonwoven fabric of this embodiment may be used as a wiper as it is. Alternatively, the nonwoven fabric of the present embodiment may be used as a wiper by bonding another sheet-like material (nonwoven fabric, film, or sheet) to one surface of the nonwoven fabric. The wiper may be held by hand and used like a dust cloth, or may be used by being attached to a jig having a wiper attachment portion at the end of a rod-like object.

The wiper may be anti-personnel or objective. The nonwoven fabric of this embodiment is particularly suitable for use as an objective wiper.
Objective wipers may be used for wiping floors, kitchens, toilets, bathtubs, furniture, vehicles, walls, screens and windows, and the like. By using water-repellent cellulose fibers, the nonwoven fabric of the present embodiment is suitable for wiping off and collecting relatively large solid dirt (food waste, hair). It is particularly suitable for wiping areas that are prone to staining, such as floors of dining rooms, living rooms, and washrooms, floors of shops such as restaurants, and floors of factories and workshops. The objective wiper may be impregnated with, for example, 100 parts by weight or more and 1000 parts by weight or less of an impregnation amount of water or an aqueous solution containing a cleaning component with respect to 100 parts by weight of the nonwoven fabric. The impregnation amount may be 150 parts by mass or more, 700 parts by mass or less, or 500 parts by mass or less with respect to 100 parts by mass of the nonwoven fabric.

A wiper for personal use may be used for wiping off dirt, cosmetics, medicines, or the like attached to a person's body. The personal wiper may impregnate 100 parts by mass of the nonwoven fabric with water or an aqueous solution containing a cleaning component in an impregnation amount of 100 parts by mass or more and 1000 parts by mass or less. Liquid-impregnated personal wiping sheets are more specifically provided as, for example, hand wipes, baby wipes, menstrual wipes, makeup remover sheets, face wash sheets, antiperspirant sheets, and nail removers.

Both wipers are used so that the wiping surface becomes the surface of the fiber layer A. The water-repellent cellulose fibers contained in the fiber layer A are deformed by the wiping pressure, so that not only fine powdery dirt but also slightly large dirt can be wiped off and collected satisfactorily. In addition, when the wiper is a wet wiper, the moderate inter-fiber gaps formed by the water-repellent cellulose fibers improve the sustained release of the liquid, and the amount of liquid released is kept relatively uniform during the wiping operation. Therefore, it is possible to reduce uneven wiping (differences in how dirt is removed) due to the difference in the amount of discharged liquid.

The following fibers were prepared as fibers used in this example.
・Water-repellent cellulose fiber 1 (“Water-repellent rayon 1.7T” in the table): Fineness 1.7 dtex, fiber length 40 mm, viscose rayon whose fiber surface has been water-repellent treated with a non-fluorine-based water repellent (trade name : Eco Liperas, manufactured by Daiwabo Rayon Co., Ltd.). In order to evaluate the water repellency of this fiber, the initial sedimentation velocity and the sedimentation velocity after washing were measured by the above method. was floating on the water. The official moisture content of this fiber was 12.8%, and the degree of secondary swelling was 53.1% as an average value measured at four points.
- Water-repellent cellulose fiber 2 ("Water-repellent Lyocell 1.7T" in the table): Lyocell having a fineness of 1.7 dtex, a fiber length of 38 mm, and having a water-repellent surface (trade name: Lyocell Dry, manufactured by Lenzing). In order to evaluate the water repellency of this fiber, the initial sedimentation velocity and the sedimentation velocity after washing were measured by the above method. was floating on the water. The official moisture content of this fiber was 11.3%, and the degree of secondary swelling was 71.0% as an average value measured at four points.
・Water-repellent cellulose fiber 3 (“water-repellent rayon 1.0T” in the table): fineness 1.0 dtex, fiber length 40 mm, viscose rayon (trade name : Eco Liperas, manufactured by Daiwabo Rayon Co., Ltd.). In order to evaluate the water repellency of this fiber, the initial sedimentation velocity and the sedimentation velocity after washing were measured by the above method. was floating on the water. The official moisture content of this fiber was 13.2%, and the degree of secondary swelling was 58.2% as an average value measured at four points.
・Water-repellent cellulose fiber 4 (“water-repellent rayon 3.3T” in the table): fineness 3.3 dtex, fiber length 40 mm, viscose rayon (trade name : Eco Liperas, manufactured by Daiwabo Rayon Co., Ltd.). In order to evaluate the water repellency of this fiber, the initial sedimentation velocity and the sedimentation velocity after washing were measured by the above method. was floating on the water. The official moisture content of this fiber was 13.0%, and the degree of secondary swelling was 58.8% as an average value measured at four points.
・Water-repellent cellulose fiber 5 (in the table, “water-repellent cotton”): fineness 1.0 dtex to 5.0 dtex, fiber length 10 mm to 60 mm, cotton with water repellent treatment on the fiber surface (product name: Hydri, Bernhardt Co., Ltd.) made). In order to evaluate the water repellency of this fiber, the initial sedimentation velocity and the sedimentation velocity after washing were measured by the above method. Almost all of them floated on the surface of the water. The sedimentation speed after washing was 26 seconds. The official moisture content of this fiber was 7.3%, and the degree of secondary swelling was 39.3% as an average value measured at four points.

- Hydrophilic cellulose fiber A ("rayon 1.7T" in the table): Viscose rayon having a fineness of 1.7 dtex and a fiber length of 40 mm (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.). When the water repellency (hydrophilicity) of this fiber was evaluated by the method described above, the sedimentation speed was 7 seconds.
・Synthetic fiber a (“PLA/PBS2.4T” in the table): A core-sheath type composite fiber (trade name : Miracle Fiber KK-PL, manufactured by Daiwabo Co., Ltd.).
・Synthetic fiber b ("PP/PE1.7T" in the table): Core-sheath type composite fiber (trade name: NBF (H ) P, manufactured by Daiwabo Co., Ltd.).
Synthetic fiber c (“PET1.45T” in the table): A single synthetic fiber (trade name: Tetoron, manufactured by Toray Industries, Inc.) made of polyethylene terephthalate having a fineness of 1.45 dtex and a fiber length of 38 mm.
・Synthetic fiber d (“PLA/PBS4.4T” in the table): A core-sheath type composite fiber (trade name : Miracle Fiber KK-PL, manufactured by Daiwabo Co., Ltd.).
・Synthetic fiber e (“Bio-PP/PE1.7T” in the table): Fineness 1.7 dtex, fiber length 51 mm, core component bio-polypropylene resin (trade name: HG475FB, Borealis), sheath component bio-polyethylene resin (trade name: SE5311, LG).

Moreover, the following was prepared as a nonwoven fabric (fiber web B) constituting the intermediate fiber layer in this example.
Wet-laid nonwoven fabric 1 (“pulp” in the table): 100% by mass of wood-derived pulp fibers (fineness of about 1.0 to 4.0 dtex, fiber length of about 0.8 mm to 4.5 mm), basis weight of 17 g/m ² Wet-laid nonwoven fabric (manufactured by Havix Co., Ltd.)
Wet-laid nonwoven fabric 2 (“pulp” in the table): Made of 100% by mass of wood-derived pulp fibers (fineness of about 1.0 to 4.0 dtex, fiber length of about 0.8 mm to 4.5 mm), basis weight of 26 g/m ² Wet-laid nonwoven fabric (manufactured by Havix)
Thermally bonded nonwoven fabric (“thermally bonded NW” in the table): A fiber web made of synthetic fiber a and having a basis weight of 17 g/m ² was prepared with a parallel carding machine, and was subjected to 5 A heat-bonded nonwoven fabric obtained by bonding fibers together using the sheath component of synthetic fiber a after heat treatment for 2 seconds. ) is a net-like sheet (trade name: CONWED NET, manufactured by ENEOS Techno Material Co., Ltd.) with openings of 11.3 mm) having an opening ratio of 96% and a basis weight of about 5.2 g / m ²

(Example 1)
40% by mass of water-repellent cellulose fiber 1, 40% by mass of hydrophilic cellulose fiber A, and 20% by mass of synthetic fiber a are mixed, and a fiber web with a target weight of about 24 g/m ² is formed using a parallel carding machine. A1 and A2 were produced.
A wet-laid nonwoven fabric 1 is laminated as an intermediate fiber layer on the fibrous web A1, a fibrous web A2 is laminated on the wet-laid nonwoven fabric 1 to form a laminated fibrous web, and the laminated fibrous web is placed on a 90-mesh plain weave support. While conveying at a speed of 4.0 m / min, a water flow of about 3 MPa water pressure is sprayed once on the surface of the fiber web A2, and then a water flow of about 3 MPa water pressure is sprayed once on the surface of the fiber web A1. A hydroentanglement treatment was performed. The nozzle used in the hydroentangling process was a nozzle with orifices of 0.12 mm diameter and spaced 0.6 mm apart, with a spacing of 15 mm between the nozzle and the fibrous web during the process.

Next, the fiber web after the hydroentangling treatment is heat-treated for 5 seconds using a hot air penetration type heat treatment machine set at 135 ° C., the fibers are bonded by the sheath component of the synthetic fiber a, and the temperature is reduced to 20 ° C. at room temperature. The nonwoven fabric of Example 1 was obtained by subjecting it to a cooling process by natural cooling in an atmosphere.

(Examples 2 to 9, Comparative Examples 1 to 4)
Examples 2 to 9 and 9 were prepared in the same manner as in Example 1, except that the types and proportions of the fibers constituting the fiber webs A1 and A2 and the target basis weight of these fiber webs were as shown in Tables 1 to 3, respectively. Nonwoven fabrics of Comparative Examples 1 to 4 were obtained.
However, in Example 7, a card web having a basis weight of 17 g/m ² was produced from hydrophilic cellulose fiber A, and this was used as fiber web B (intermediate fiber layer after production of nonwoven fabric).
In Example 9 and Comparative Example 4, no synthetic fiber was used, so the heat bonding treatment was not performed, and instead the drying treatment was performed using a hot air penetrating heat treatment machine set at 100°C. Also in Comparative Example 3, the heat bonding treatment was not performed, and instead the drying treatment was performed using a hot air penetrating heat treatment machine set at 100°C.
In Example 6, Comparative Example 2 and Comparative Example 4, nonwoven fabrics were produced without using the fiber web B, and the nonwoven fabrics had a single-layer structure without an intermediate fiber layer.

(Examples 10-20)
The same procedure as in Example 1 was performed except that the types and proportions of the fibers constituting the fiber webs A1 and A2, the target basis weight of these fiber webs, and the fiber web B were as shown in Tables 4 and 5, respectively. Nonwoven fabrics of Examples 10 to 20 were obtained respectively.
In Example 12, no synthetic fiber was used in the fiber layer A, so the heat bonding treatment was not performed, and instead the drying treatment was performed using a hot air penetrating heat treatment machine set at 100°C.

The nonwoven fabric was evaluated as follows.
<Thickness, thickness reduction rate, bulk density of nonwoven fabric>
Using a thickness measuring machine (THICKNESS GAUGE model CR-60A (trade name) manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), the thickness of the nonwoven fabric is measured while a load of 0.3 kPa or 1.96 kPa is applied to the nonwoven fabric. It was measured. Also, the reduction in thickness when a load of 1.96 kPa was applied from the thickness when a load of 0.3 kPa was applied was obtained as a thickness reduction rate.
The bulk density was calculated from the thickness and basis weight when a load of 0.3 kPa was applied.

<Strength and Elongation>
According to JIS L 1913:2010 6.3, a tensile test was performed using a constant-speed tension type tensile tester under the conditions of a sample piece width of 5 cm, a grip interval of 10 cm, and a tensile speed of 30 ± 2 cm / min. , and the load value (tensile strength) at break, elongation, and stress at 10% elongation (force required for 10% elongation) were measured. The tensile test was performed with the machine direction (MD direction) and the transverse direction (CD direction) of the nonwoven fabric as tensile directions. Each evaluation result is shown as an average of values measured for three samples.
Tensile strength and the like were measured when dry (standard time, DRY) and when wet (WET).
The wet (WET) measurement was performed by impregnating 100 parts by mass of the sample with 250 parts by mass of distilled water.

<Fluff removal amount measurement test>
a) A disk (diameter 70 mm, 350 g) whose surface is covered with urethane foam (manufactured by INOAC Corporation, trade name Maltfilter MF-30, thickness 5 mm) is placed so that the rotation axis is shifted from the disk center by 20 mm. Attach to the rotating shaft as shown.
b) The same urethane foam as above is spread, and the nonwoven fabric is fixed on the table so that one side of the nonwoven fabric is exposed.
c) placing the disc on top of the non-woven fabric; At this time, the only load applied to the nonwoven fabric is the weight of the disk itself.
d) Rotate the rotating shaft to rotate the disk on the nonwoven fabric. Circular motion is performed for 7 sets, with 3 rotations clockwise and 3 rotations counterclockwise as 1 set. The rotation speed at this time is about 3 seconds per one rotation.
e) After 7 sets of circular movements, collect the fibers falling off the nonwoven fabric and adhering to the surface of the urethane foam covering the disk.
f) The above operations a) to e) are performed on n=3 nonwoven fabrics. For each of the three nonwoven fabrics, the mass of the fibers that have fallen off is measured, and the average value is taken as the fluff amount.

<Dirt collection>
[Dust trapping]
0.20 g of test powder (7 types) according to JIS Z 8901 is uniformly dispersed in a rectangular area of 5 cm long x 15 cm wide (hereinafter referred to as "dust dispersion area") approximately in the center of the surface of a white acrylic plate. The nonwoven fabrics (29 cm long and 21 cm wide) of Examples and Comparative Examples were used as wipers to wipe off test powder (dust).

For wiping, the area contributing to wiping is 26 cm in the vertical direction and 16 cm in the horizontal direction. The head portion of the wiper [tool main body], manufactured by Kao Corporation) was attached, and the test was carried out while a load of 400 gf was applied. Wiping was performed by reciprocating the wiper once on the surface of the white acrylic plate.

More specifically,
・Place the wiper in the center of the dust distribution area so that the vertical direction of the wiper matches the vertical direction of the dust distribution area,
・From there, move the wiper by 250 mm in the direction toward the left end of the dust dispersion area to rub the dust (white acrylic plate),
・Then, after moving the wiper 500mm in the direction toward the right edge of the dust dispersion area,
- Further, the wiper was moved 250 mm in the direction toward the left end of the dust dispersion area, and the wiper was reciprocated once.

After one reciprocation of the wiper, the dust collection performance was obtained from the mass of the nonwoven fabric measured in advance and the mass of the nonwoven fabric measured after wiping. For each nonwoven fabric, the wiping was measured three times while the wiping surface of the nonwoven fabric was renewed, and the average value was taken as the dust collection rate.

[Hair collecting property (wet state)]
A total of 5 hairs (about 5 cm in length), 3 horizontally and 2 vertically, were placed at intervals on the flooring and wiped off with the nonwoven fabrics of Examples and Comparative Examples.

The wiping was performed in a wet state by impregnating 100 parts by mass of the nonwoven fabric with 300 parts by mass of distilled water. In addition, the wiper jig (trade name: Quickle wiper [tool main body]) was applied to the nonwoven fabric so that the surface of the fiber layer A became the wiping surface so that the area contributing to wiping was 26 cm in the vertical direction and 16 cm in the horizontal direction. ], manufactured by Kao Corporation), and a load of 400 gf was applied. The wiping was carried out by reciprocating the wiper once over the hair in the same manner as the method employed in the evaluation of the dust collection property. After wiping, the hair collection rate (%) was obtained from the number of hairs wiped from the flooring. For each nonwoven fabric, the wiping was measured three times while the wiping surface of the nonwoven fabric was renewed, and the average value was taken as the hair collection rate.

[Sesame collection property (wet state)]
The sesame-catching property was evaluated by placing 10 sesame seeds on the flooring in three rows (rows of 3-4-3) at intervals and using the same method as the evaluation of the hair-catching property (wet state). After wiping with a non-woven fabric, the collection rate (%) was obtained from the number of sesame wiped off from the flooring. For each nonwoven fabric, the wiping was measured three times with the wiping surface of the nonwoven fabric being renewed, and the average value was taken as the sesame collection rate.

<Initial release amount, liquid residual rate>
For the initial release amount and liquid retention rate, prepare a nonwoven fabric of the same size as that used in the stain collection test, and measure the weight of the nonwoven fabric NW _d when dried. 100 parts by mass of the nonwoven fabric was impregnated with 300 parts by mass of distilled water, and the nonwoven fabric weight NW _w was measured. A wiper jig (trade name: Quickle wiper [tool main body] head part, (manufactured by Kao Corporation). With a load of 400 gf applied, the nonwoven fabric was placed on the conveyor so that the direction of movement of the conveyor coincided with the lateral direction (16 cm) of the nonwoven fabric, and the conveyor was operated at 5 m/min. The nonwoven fabric weight NW _0.5 was measured when the conveyor was rotated once (0.5 tatami mat = 0.81 m ² ), and the initial release amount RA ₁ was obtained from the following equation.

RA ₁ = _NWw - NW _0.5

Subsequently, the nonwoven fabric was similarly placed on the conveyor, and the weight of the nonwoven fabric (NW ₂ , NW ₄ , NW 6 , NW ₈ ) was measured every 2nd, 4th, _6th and 8th rounds of the conveyor. asked for a rate.
RR ₂ =100−(( _NWw − _NW2 )/( _NWw − _NWd )×100)
RR ₄ =100−(( _NWw − _NW4 )/( _NWw − _NWd )×100)
RR ₆ =100−((NW _w −NW ₆ )/(NW _w −NW _d )×100)
RR ₈ =100−(( _NWw − _NW8 )/( _NWw − _NWd )×100)

Tables 1 to 5 show the evaluation results of each example and each comparative example.

All of the nonwoven fabrics of Examples 1-19 exhibited generally excellent dirt pick-up properties (hair pick-up >30%, sesame pick-up >60%, and dust pick-up >34%) with at least two stains. and showed a particularly high sesame collection rate. Also, all of the nonwoven fabrics of Examples 1-20 met a fluff removal amount of 10 mg or less, and some of the examples further met an initial release amount of 0.8 g or less.

In Example 2, among the examples containing the same water-repellent rayon as the water-repellent cellulose fibers, the ratio of the water-repellent cellulose fibers is the smallest, and the ratio of the hydrophilic cellulose fibers is the largest, and the entanglement between the fibers progresses further. It was easy. Therefore, among the examples containing water-repellent rayon, Example 2 tended to have a slightly lower ability to collect any dirt than the other examples.

From the results of Examples 1 to 4, the higher the ratio of water-repellent cellulose fibers in the fiber layer A, the higher the sesame collection rate, and the better the ability to collect slightly large dirt such as food scraps. It was found that there was a tendency for the amount of falling out to increase. It is considered that this is because the water-repellent cellulose fibers are less likely to be entangled by water flow, and the fiber strength and stiffness are low.

Comparing Example 1 and Example 6, Example 6 showed higher dirt pick-up. Since Example 6 does not include an intermediate fiber layer, the degree of entanglement between fibers is reduced, the fiber density is lowered, and it is believed that dirt is easily retained.

Examples 1 and 8 differ in the type of synthetic fibers contained in the fiber layer A. In comparison with Example 1, Example 8 was superior in dust collection. This is because the fineness of the synthetic fibers used in Example 8 was smaller than that of the synthetic fibers used in Example 1, and finer inter-fiber voids were formed. This is probably due to the fact that they were collected.

Examples 10 and 11 use water-repellent cotton and water-repellent lyocell, respectively, as water-repellent cellulose fibers. In comparison to Example 1, Example 10 exhibited lower dust retention, but was superior to Comparative Examples 1 and 2 in retention of other soils. Also, in comparison with Example 1, Example 10 had a larger initial release amount. On the other hand, in Example 10, the fluff coming off amount was small. From these, in Example 10, it is inferred that the water repellency of the water-repellent cotton is lower than that of the water-repellent rayon, the fibers are more entangled, and the water-repellent cotton itself retains the liquid. be. As a result, in Example 10, the liquid contained in the water-repellent cotton during wiping increased the resistance during wiping, hindering the collection of dirt by the nonwoven fabric. It is considered that the amount of fluff coming off was reduced due to stronger entanglement between them.
In comparison with Example 1, Example 11 had higher hair collecting properties. This is because in Example 11, the entanglement of the fibers due to the water stream progressed more than in Example 1, making it easier for the columnar water stream to form groove-like streaks on the surface of the nonwoven fabric, and the hair was collected along these grooves. Possibly.

In Example 12, the intermediate fibrous layer was composed of a heat-bonded nonwoven fabric, and exhibited the same level of dirt-collecting properties as those of the other Examples, but the initial release amount was larger. It is considered that this is because the intermediate fiber layer made of synthetic fibers hardly retains the liquid, and a large amount of the liquid in the intermediate fiber layer was initially discharged. In addition, Example 12 exhibits a relatively higher amount of fluff coming off than the other examples. This is probably because the fiber layer A did not contain synthetic fibers and the fibers were not bonded to each other on the surface of the nonwoven fabric.

In Example 13, a thin scrim is used for the intermediate fiber layer, and the fabric weight of the fiber layer A is increased compared to Example 1. Example 13 showed high hair picking properties in comparison with Example 1. This is presumably because the scrim was partly exposed on the surface of the fibers, making it easier for the hair to get caught in the scrim. In addition, Example 13 showed a large initial release amount. This is believed to be due to the poor retention of liquid by thin scrims. The reason why the initial release amount of Example 13 is smaller than that of Example 12 is considered to be that the basis weight of the fiber layer A of Example 13 is large, and the hydrophilic cellulose fibers contained therein retain liquid to some extent. .

Example 14 is an example in which synthetic fibers thicker than those used in Example 1 are used. In comparison with Example 1, Example 14 exhibited high hair- and sesame-collecting properties. This is probably because the use of the thick synthetic fibers reduces the number of bonding points formed by the synthetic fibers in the fiber layer A, thereby increasing the flexibility of the fibers. Example 14 showed a higher initial release than Example 1. It is considered that this is also due to the fact that the number of bonding points is reduced and the inter-fiber voids in the fiber layer A are increased.

Example 15 has a structure in which the fabric weight of the intermediate fiber layer is larger than that of Example 1, and the fabric weight of the fiber layer A is larger. In comparison with Example 1, Example 15 was excellent in hair collecting properties. This is because the amount of pulp, which is hydrophilic cellulose, is large, so that the entanglement of the fibers by water flow progresses, and the columnar water flow makes it easier to form groove-like streaks on the surface of the nonwoven fabric. was collected. Also, Example 15 shows a smaller initial release than Example 1. It is believed that this is because the fiber layer with a higher basis weight is more likely to retain the liquid. Furthermore, Example 15 shows less fluff loss than Example 1. It is considered that this is because the fiber layer A has a small basis weight, and the amount of water-repellent cellulose fibers that tend to come off is small.

In Example 16, the fineness of the hydrophilic cellulose fibers (rayon) contained in the fiber layer A was made smaller than that used in Example 1. When fibers with a small fineness are used, the entanglement of the fibers progresses, the entanglement of the fibers becomes stronger, and the gaps between the fibers in the fiber layer A tend to become smaller. For this reason, it is considered that the dirt collecting property was slightly lower than that of Example 1, and the amount of fluff coming off was reduced.

Examples 17 and 18 vary the fineness of the water-repellent cellulose fibers. From the comparison of Examples 1, 17 and 18, the greater the fineness of the water-repellent cellulose fibers, the higher the soil-collecting property and the tendency to increase the initial release amount. This is considered to be due to the formation of large inter-fiber voids by using water-repellent cellulose fibers having a large fineness. The amount of fluff removed increases as the fineness increases, and this is considered to be due to the fact that the entanglement points of the fibers are reduced by increasing the fineness.

Example 19 is an example using synthetic fibers using polypropylene and polyethylene made from biomass raw materials. In comparison with Example 8 in which synthetic fibers using polypropylene and polyethylene made from petroleum-derived raw materials were used, there was no significant change in performance. From this result, it was confirmed that the synthetic fiber produced using the resin made from biomass material can be applied to the nonwoven fabric of the present disclosure without any problem.

None of the nonwoven fabrics of Comparative Examples 1 and 2 contained water-repellent cellulose fibers and had a large percentage of hydrophilic cellulose fibers. Therefore, even if it compared with any Example, it was inferior in the collection property of dirt.

The nonwoven fabric of Comparative Example 4 was good in terms of dirt-collecting properties, but because the water-repellent cellulose fibers accounted for a large proportion of the entire nonwoven fabric, fluffing easily occurred, and the amount of fluffing was the largest. . The nonwoven fabric of Comparative Example 4 also had a high initial release of liquid. This is probably because the proportion of water-repellent cellulose fibers is large and the fibers are not bonded to each other, so that the gaps between the fibers become excessively large, and the liquid accumulated in the gaps is released all at once.

The nonwoven fabric of Comparative Example 3 corresponds to that of Example 9 in which the water-repellent cellulose fibers were replaced with polyethylene terephthalate fibers. Compared with the nonwoven fabric of Example 9, the nonwoven fabric of Comparative Example 3 had lower dirt collecting properties. This is probably because the nonwoven fabric of Comparative Example 3 did not contain water-repellent cellulose fibers, and therefore the fibers were less likely to deform due to wiping pressure. In addition, the nonwoven fabric of Comparative Example 3 had a larger initial release amount than that of Example 9. This is probably because the nonwoven fabric of Comparative Example 3 has a large thickness and is bulky, so that the voids between the fibers become large, and the liquid accumulated in the voids is released all at once.

This embodiment includes the following aspects.
(Aspect 1)
A nonwoven fabric having a first surface and a second surface opposite the first surface,
Based on the total mass of the nonwoven fabric, it contains water-repellent cellulose fibers at a ratio of 10% by mass or more and less than 75% by mass, and other fibers at a ratio of more than 25% by mass and 90% by mass or less,
At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fibers at a ratio of 10% by mass or more and the other fibers at a ratio of 90% by mass or less,
are integrated by entangling the fibers,
Non-woven fabric for wipers.
(Aspect 2)
the nonwoven fabric has a first fibrous layer, a second fibrous layer, and an intermediate fibrous layer positioned between the first fibrous layer and the second fibrous layer;
The first surface is the surface of the first fiber layer, the second surface is the surface of the second fiber layer,
Either one or both of the first fiber layer and the second fiber layer is the fiber layer A,
The nonwoven fabric for wipers according to aspect 1.
(Aspect 3)
The wiper nonwoven fabric of aspect 2, wherein the intermediate fibrous layer comprises hydrophilic cellulose fibers.
(Aspect 4)
The nonwoven fabric for wipers according to any one of aspects 1 to 3, wherein the fiber layer A contains hydrophilic cellulose fibers as the other fibers.
(Aspect 5)
The nonwoven fabric for wipers according to aspect 4, wherein the fiber layer A contains the hydrophilic cellulose fibers at a ratio of more than 0% by mass and 75% by mass or less.
(Aspect 6)
Aspect 1, wherein the fiber layer A contains, as the other fibers, one or more types of synthetic fibers selected from synthetic fibers containing biomass raw materials, biodegradable synthetic fibers, and synthetic fibers containing recycled raw materials. The nonwoven fabric for wipers according to any one of -5.
(Aspect 7)
Aspect 6, wherein the fiber layer A contains one or more types of synthetic fibers selected from synthetic fibers containing the biomass raw material and biodegradable synthetic fibers at a ratio of more than 0% by mass and 35% by mass or less. non-woven fabric for wipers.
(Aspect 8)
A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising:
As the fibrous web A constituting at least one of the first surface and the second surface, at least a fibrous web containing water-repellent cellulose fibers in a proportion of 10% by mass or more and other fibers in a proportion of 90% by mass or less. and producing a fibrous web B other than the fibrous web A; and laminating the fibrous web A and the fibrous web B to produce a laminated fibrous web, and subjecting the fibers to a process of entangling them. including
In producing the fibrous web A and the fibrous web B, the laminated fibrous web contains the water-repellent cellulose fiber at a ratio of 10% by mass or more and less than 75% by mass, and the other fiber is more than 25% by mass and 90% by mass. Select the type and proportion of fibers that make up each fiber web, and the basis weight of each fiber web so that it contains the following proportions,
A method for producing a nonwoven fabric for wipers.
(Aspect 9)
The fiber web B is arranged between two same or different fiber webs A, or between one fiber web A and a second fiber web B, which is another fiber web, to form the laminated web. and subjecting the laminated web to a treatment to entangle the fibers;
A method for producing a wiper nonwoven fabric according to aspect 8.
(Mode 10)
A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising:
The fibrous web A constituting at least one of the first surface and the second surface contains water-repellent cellulose fibers at a ratio of 10% by mass or more and less than 75% by mass, and more than 25% by mass and 90% by mass of the other fibers. % or less, and subjecting the single-layer or laminated web of the fiber web A to a treatment for entangling the fibers,
A method for producing a nonwoven fabric for wipers.
(Aspect 11)
100 parts by mass of the wiper nonwoven fabric of any one of aspects 1 to 7 is impregnated with a liquid in an amount of 100 parts by mass or more and 1000 parts by mass or less,
The surface of the fiber layer A is used as a wiping surface,
wiper.
(Aspect 12)
The wiper of aspect 11, which is an objective wiper.

The nonwoven fabric of the present disclosure has a low rigidity and has the property of swelling with the liquid absorbed from the cross section of the fiber when wetted with liquid, so it contains a predetermined proportion of water-repellent cellulose fibers that are easily deformed by wiping pressure. Therefore, the nonwoven fabric of the present disclosure can be suitably used as a wiper with excellent dirt-collecting properties, particularly as an objective wiper for wiping off somewhat large-sized dirt.

Claims (12)

A nonwoven fabric having a first surface and a second surface opposite the first surface,
Based on the total mass of the nonwoven fabric, it contains water-repellent cellulose fibers at a ratio of 10% by mass or more and less than 75% by mass, and other fibers at a ratio of more than 25% by mass and 90% by mass or less,
At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fibers at a ratio of 10% by mass or more and the other fibers at a ratio of 90% by mass or less,
are integrated by entangling the fibers,
Non-woven fabric for wipers. the nonwoven fabric has a first fibrous layer, a second fibrous layer, and an intermediate fibrous layer positioned between the first fibrous layer and the second fibrous layer;
The first surface is the surface of the first fiber layer, the second surface is the surface of the second fiber layer,
Either one or both of the first fiber layer and the second fiber layer is the fiber layer A,
The nonwoven fabric for wipers according to claim 1. 3. The wiper nonwoven according to claim 2, wherein said intermediate fibrous layer comprises hydrophilic cellulose fibers. The wiper nonwoven fabric according to any one of claims 1 to 3, wherein the fiber layer A contains hydrophilic cellulose fibers as the other fibers. The nonwoven fabric for wipers according to claim 4, wherein the fiber layer A contains the hydrophilic cellulose fibers at a ratio of more than 0% by mass and 75% by mass or less. The fiber layer A includes, as the other fibers, one or more types of synthetic fibers selected from synthetic fibers containing biomass raw materials, biodegradable synthetic fibers, and synthetic fibers containing recycled raw materials. The nonwoven fabric for wipers according to any one of 1 to 3. The fiber layer A contains one or more types of synthetic fibers selected from synthetic fibers containing biomass raw materials and biodegradable synthetic fibers at a ratio of more than 0% by mass and 35% by mass or less. 7. The nonwoven fabric for wipers according to 6. A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising:
As the fibrous web A constituting at least one of the first surface and the second surface, at least a fibrous web containing water-repellent cellulose fibers in a proportion of 10% by mass or more and other fibers in a proportion of 90% by mass or less. and producing a fibrous web B other than the fibrous web A; and laminating the fibrous web A and the fibrous web B to produce a laminated fibrous web, and subjecting the fibers to a process of entangling them. including
In producing the fibrous web A and the fibrous web B, the laminated fibrous web contains the water-repellent cellulose fiber at a ratio of 10% by mass or more and less than 75% by mass, and the other fiber is more than 25% by mass and 90% by mass. Select the type and proportion of fibers that make up each fiber web, and the basis weight of each fiber web so that it contains the following proportions,
A method for producing a nonwoven fabric for wipers. The fiber web B is arranged between two same or different fiber webs A, or between one fiber web A and a second fiber web B, which is another fiber web, to form the laminated web. and subjecting the laminated web to a treatment to entangle the fibers;
The manufacturing method of the nonwoven fabric for wipers according to claim 8. A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising:
The fiber web A constituting at least one of the first surface and the second surface contains water-repellent cellulose fibers at a ratio of 10% by mass or more and less than 75% by mass, and the other fibers are more than 25% by mass and 90% by mass. % or less, and subjecting the single-layer or laminated web of the fiber web A to a treatment for entangling the fibers,
A method for producing a nonwoven fabric for wipers. 100 parts by mass of the wiper nonwoven fabric according to any one of claims 1 to 3 is impregnated with a liquid in an amount of 100 parts by mass or more and 1000 parts by mass or less,
The surface of the fiber layer A is used as a wiping surface,
wiper. 12. The wiper of claim 11, which is an objective wiper.