Nonwoven fabric for wipers, method for manufacturing the same, and wipers

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

Technical Field

[0001] The present disclosure relates to a nonwoven fabric for a wiper and a wiper including the nonwoven fabric.

Background Art

[0002] One use of nonwoven fabrics is a wiper for wiping dirt from a human body or an object. For example, Patent Document 1 proposes a wet wiper in which a fabric containing hydrophilic fibers and hydrophobic fibers and satisfying a specific relationship between the content of the hydrophobic fibers and the proportion of the hydrophobic fibers present on the fabric surface is impregnated with a disinfectant solution. Further, Patent Document 2 proposes using a nonwoven fabric containing a blend of artificial cellulose fibers and hydrophobic artificial cellulose fibers and treated with a wetting agent as a wet wipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] To provide a nonwoven fabric that gives a wiper that is more excellent in the collection property of wiped dirt and further has less lint shedding.

Means for Solving the Problems

[0005] The nonwoven fabric according to the present disclosure is a nonwoven fabric having a first surface and a second surface opposite to the first surface, including 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 including other fibers in a proportion of more than 25% by mass and 90% by mass or less, At least one of the first surface and the second surface is the surface of a fiber layer A containing the water-repellent cellulose fiber at a ratio of 10% by mass or more and containing the other fiber at a ratio of 90% by mass or less. Integrated by entanglement of fibers, It is a non-woven fabric for a wiper.

Effect of the Invention

[0006] In the non-woven fabric for a wiper of the present disclosure, the fiber layer A constituting one surface of the non-woven fabric contains a water-repellent cellulose fiber at a predetermined ratio, and the ratio of the water-repellent cellulose fiber is within a predetermined range based on the total mass of the non-woven fabric. With this configuration, when the non-woven fabric of the present disclosure is used as a wiper, the water-repellent cellulose fiber itself is easily deformed by wiping pressure, and the degree of freedom of the fibers in the non-woven fabric is large due to the slightly low entanglement property of the water-repellent cellulose fiber, and the inter-fiber voids are easily deformed by wiping pressure. As a result, it becomes possible to improve the dirt collection property. Further, the non-woven fabric for a wiper of the present disclosure can suppress the amount of fibers (fiber shedding) that fall off from the non-woven fabric during wiping, and depending on the configuration, it is further possible to improve the sustained release property of the liquid when the liquid is impregnated.

Modes for Carrying Out the Invention

[0007] (Background to the non-woven fabric for a wiper of the present disclosure) The wet wiper described in Patent Document 1 utilizes the property that the hydrophobic fibers on the fabric surface are not impregnated with the impregnating liquid, so the hydrophobic fibers do not swell and are not deformed by the wiping pressure during wiping, and can efficiently scrape off the dirt on the wiped surface. Further, in the wet wiper described in the same document, the scraped-off dirt is absorbed into a portion where the ratio of hydrophilic fibers inside the fabric is large, making it difficult to return. In Patent Document 1, "hydrophobic fiber" is defined as having the property of not being able to contain water, and synthetic fibers and inorganic fibers are exemplified as hydrophobic fibers.

[0008] The inventors constructed the fabric described in Patent Document 1 as a nonwoven fabric and evaluated its wiping performance. They found that, depending on the type of dirt, the wiping performance was sometimes slightly inferior. In particular, for wipers used to clean floors, the ability to capture solid dirt larger in size than dust, such as food crumbs and hair (the property of retaining wiped dirt within the wiper) is important, but the wiper in Patent Document 1 still had room for improvement in this respect.

[0009] The inventors of this invention investigated a configuration that would improve the ability to collect somewhat large solid dirt particles, and came to the idea that deformation of the fibers due to the wiping pressure during wiping might be useful for collecting these dirt particles. In other words, they hypothesized that by deforming the fibers to some extent due to the wiping pressure, the interfiber gaps would partially widen, allowing dirt to enter these gaps, and then the deformed fibers would return to their original shape, making it possible to efficiently capture the dirt.

[0010] While fiber deformation due to wiping pressure is more likely to occur with higher fiber swelling and, consequently, higher hydrophilicity, using more highly hydrophilic fibers increases the overall hydrophilicity of the nonwoven fabric. The hydrophilicity of the nonwoven fabric affects the sustained release of liquid when used as a wet wiper. Generally, a higher proportion of hydrophilic fibers in the nonwoven fabric tends to release a large amount of liquid at the beginning of use.

[0011] The inventors, after considering the above and conducting various studies, have found that using water-repellent cellulose fibers can significantly improve the ability to capture relatively large solid dirt particles. As described later, water-repellent cellulose fibers have a water-repellent outer surface and do not easily absorb moisture. However, when the fiber is cut, a hydrophilic portion (a portion that does not contain water-repellent components) is exposed at the fiber cross-section, and it is thought that liquid can penetrate to some extent through this exposed portion. In addition, water-repellent cellulose fibers have less rigidity than synthetic fibers and are somewhat easily deformed even when not in a swollen state. From the above, it is inferred that water-repellent cellulose fibers are more easily deformed by wiping pressure compared to synthetic fibers, and thus improve the ability to capture dirt.

[0012] Furthermore, when using water-repellent cellulose fibers, if the fibers are entangled and integrated by the action of aqueous fluids such as water flow entanglement or water vapor entanglement, the water-repellent properties of the cellulose fibers make it difficult for the entanglement to progress, and the fibers are entangled with a relatively high degree of freedom. In such nonwoven fabrics, deformation of the interfiber gaps is easily caused by wiping pressure, either with or without deformation of the fibers, and it is presumed that this also improves the dirt-collecting ability of water-repellent cellulose fibers.

[0013] Furthermore, the inventors have found that by appropriately selecting the amount of water-repellent cellulose fibers used, the amount of lint shedding can be reduced, and the amount of fibers adhering to the object during wiping can be decreased. Because water-repellent cellulose fibers do not easily entangle themselves, they tend to fall off nonwoven fabrics. However, by adjusting the amount they occupy in the entire nonwoven fabric and combining them with other fibers or fiber layers containing other fibers, it is possible to reduce the likelihood of them falling off.

[0014] The use of water-repellent cellulose fibers is also desirable from the perspective of Sustainable Development Goals (SDGs). Cellulose fibers are biodegradable and are attracting attention as an environmentally friendly material. Therefore, the nonwoven fabric disclosed herein can provide a wiper that has excellent wiping performance and is also easily accepted by consumers from the perspective of SDGs.

[0015] While Patent Document 2 describes the use of nonwoven fabric made from hydrophobic artificial cellulose fibers as a wet wipe for application to the human body as a hygiene product, that document proposes shortening the liquid penetration time through treatment with a wetting agent. Therefore, it is not designed to take into account the sustained release of liquid when wiping relatively large areas such as floors with a single wiper, and it is not sufficient in terms of capturing large solid dirt particles. The embodiments of the nonwoven fabric for wipers relating to this disclosure will be described below.

[0016] First, we will explain the fibers that make up the nonwoven fabric for wipers related to this disclosure (hereinafter also simply referred to as "nonwoven fabric").

[0017] (Water-repellent cellulose fiber) Cellulose fibers are inherently hydrophilic, but in this disclosure, cellulose fibers that have been artificially given water-repellent properties are referred to as "water-repellent cellulose fibers."

[0018] The type of cellulose fiber is not particularly limited. Cellulose fibers include the following: (1) Natural fibers derived from plants such as cotton, flax, linen, ramie, jute, banana, bamboo, kenaf, ginger lily, hemp, and kapok; (2) Rayon and polynosic obtained by the viscose process, cupro obtained by the copper ammonia process, and solvent-spun cellulose fibers such as Tencel® and lyocell obtained by the solvent spinning process, as well as other regenerated fibers; (3) Cellulose fibers obtained by melt spinning; (4) Semi-synthetic fibers such as acetate fibers; and (5) Pulps such as mechanical pulp, recycled pulp and chemical pulp

[0019] Water-repellent cellulose fibers may be obtained by imparting water repellency to these cellulose fibers by attaching a water-repellent agent. Alternatively, water-repellent cellulose fibers may be obtained by treating cellulose fibers having carboxyl groups and / or sulfonic acid groups with a treatment solution containing an isocyanate compound and a non-fluorine water-repellent agent. Water-repellent cellulose fibers obtained by such a method are disclosed, for example, in Japanese Patent Application Publication No. 2019-65443.

[0020] In terms of the tendency for the rigidity and flexibility of nonwoven fabrics to decrease, it is preferable for water-repellent cellulose fibers to contain water-repellent rayon. Rayon is also preferable because its cross-sectional shape is chrysanthemum-shaped, which allows for effective water repellency. Furthermore, the chrysanthemum-shaped fiber cross-section of rayon is observed as streaky irregularities extending in the length direction on the fiber surface. These irregularities provide interfiber voids suitable for trapping dirt, and also allow dirt to be trapped in the recesses themselves. In addition, since viscose rayon has a higher official moisture content and secondary swelling degree compared to other cellulose fibers (e.g., cotton, lyocell), it is easier to impart the effect of having a water-repellent surface while having hydrophilic and swellable interiors (e.g., deformation due to wiping pressure when wet).

[0021] Examples of water-repellent rayons on the market include EcoReperus (trade name, water-repellent viscose rayon) manufactured by Daiwabo Rayon Co., Ltd., and Olea (trade name, water-repellent viscose rayon) manufactured by Kelheim Fibres GmbH. EcoReperus (trade name) is particularly preferred because it exhibits high water repellency and has high durability, and its water repellency does not easily deteriorate even when subjected to water entanglement treatment, for example.

[0022] Alternatively, as a water-repellent cellulose fiber, solvent-spun cellulose fibers such as lyocell, which have been given water-repellency, are preferably used because they show little decrease in fiber strength when wet. As an example of a water-repellent solvent-spun cellulose fiber, Lenzing's Lyocell Dry (trade name, water-repellent lyocell) is on the market.

[0023] The fineness of the water-repellent cellulose fiber 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 fiber may be 6.0 dtex or less, 5.0 dtex or less, or 3.0 dtex or less. In one embodiment, the fineness of the water-repellent cellulose fiber is 0.6 dtex or more and 6.0 dtex or less. When the fineness of the water-repellent cellulose fiber is within the above range, appropriate voids are formed in the fiber layer A, making it easy to retain liquid. 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 with fineness outside the above range may be used. Generally, the fineness of pulp is about 1.0 dtex or more and 4.0 dtex or less, and its fiber length is about 0.8 mm or more and 4.5 mm or less.

[0024] The fiber length of the water-repellent cellulose fiber is not particularly limited and may be appropriately selected depending on the material, its manufacturing method, the method for producing fiber layer A, the manufacturing method for the nonwoven fabric, etc. The water-repellent cellulose fiber is, for example, a short fiber. When fiber layer A is made from a card web, the fiber length of the water-repellent cellulose fiber may be 100 mm or less, 75 mm or less, or 65 mm or less. The fiber length of the short fiber water-repellent cellulose fiber described above may be 10 mm or more, 20 mm or more, or 30 mm or more. In the above case, in one embodiment, the fiber length of the water-repellent cellulose fiber may be 10 mm or more and 100 mm or less. When fiber layer A is made from an airlaid web, the fiber length of the water-repellent cellulose fiber may be 2 mm or more and 20 mm or less.

[0025] In this embodiment, multiple water-repellent cellulose fibers may be used, each differing in one or more of the following: material, fiber length, and fineness.

[0026] The water repellency of the fibers can be evaluated by the sedimentation velocity (6(1) k) measured by the following method, in accordance with the standards for medical gauze and medical absorbent cotton specified in Pharmaceutical and Food Safety Bureau Notification No. 0630001.

[0027] Prepare two types of fibers: one in its original state (initial), and another after washing and drying in warm water (40°C) for 2 minutes three times to remove any attached oils, etc. Next, defibrillate the fibers in each state using a carding machine to prepare fiber aggregates. Roll 0.3g of these fiber aggregates into a ball with a diameter of 2cm or less and gently drop it into 200mm of water at a water temperature of 24-26°C from a height of 12mm above the surface. The time it takes for the fiber aggregate to sink below the water surface after being dropped is defined as the initial and post-washing sedimentation velocities of the fibers.

[0028] If the fibers cannot be defibrated by a carding machine (for example, if the fiber length is short), 0.3g of the collected fibers may be rolled up and dropped into water as is. Alternatively, if the fibers have already taken the form of a fiber aggregate (for example, a wet-laid nonwoven fabric or airlaid nonwoven fabric) and it is difficult to defibrate them with a carding machine, 0.3g of a 1cm x 1cm piece of nonwoven fabric may be dropped into water.

[0029] The initial settling rate of the water-repellent cellulose fibers is preferably 1 minute or more, more preferably 5 minutes or more, and particularly preferably 10 minutes or more. In particular, it is preferable that at least some of the water-repellent cellulose fibers have not settled below the water surface 10 minutes after being dropped into the water. At this time, the water-repellent cellulose fibers may have absorbed water. In particular, cellulose fibers in which some or all of the fibers are floating on the water surface after 1 minute are especially preferred as water-repellent cellulose fibers. Similarly, the settling rate of the water-repellent cellulose fibers after washing is also preferably 1 minute or more, more preferably 5 minutes or more, and particularly preferably 10 minutes or more. However, the settling rate after washing may be outside this range as long as the initial settling rate meets the above range.

[0030] Furthermore, while water-repellent cellulose fibers exhibit water repellency and the aforementioned settling velocities due to their water-repellent surface treatment, they retain moisture within the fiber once wet. Therefore, the official moisture content of water-repellent cellulose fibers (especially water-repellent rayon) is equivalent to that of the same type of cellulose fiber that has not been treated with a water-repellent coating. Their degree of secondary swelling is lower than that of untreated cellulose fibers, but tends to be higher than that of general synthetic fibers. For example, untreated viscose rayon has a secondary swelling degree (water swelling degree: measured according to JIS L1015:2010 8.26) of approximately 80% to 90%, while water-repellent rayon has a secondary swelling degree of approximately 45% to 55%. Additionally, water-repellent rayon has an official moisture content (measured according to JIS L 1015) of approximately 10% to 13%, which is equivalent to the official moisture content (11%) of general untreated rayon.

[0031] (Other fibers) The other fibers that constitute fiber layer A together with the water-repellent cellulose fibers are not particularly limited. The 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 they may be synthetic fibers or natural fibers. Two or more types of fibers may be used as the other fibers. Examples of other fibers, such as hydrophilic cellulose fibers and synthetic fibers, are described below.

[0032] [Hydrophilic cellulose fiber] As described above, hydrophilic cellulose fibers refer to cellulose fibers that have not been given water-repellent properties and possess their inherent hydrophilicity. Therefore, examples of hydrophilic cellulose fibers are the same as those explained for water-repellent cellulose fibers.

[0033] Hydrophilic cellulose fibers may be regenerated fibers. Regenerated fibers are preferred because their fineness can be easily adjusted and they have little variation. Among regenerated fibers, viscose rayon is preferred as a constituent fiber for wiper nonwoven fabrics because it has the characteristics described above in relation to water-repellent cellulose fibers. Furthermore, the use of viscose rayon is cost-effective.

[0034] The fineness of the hydrophilic cellulose fibers may be, for example, between 0.2 dtex and 6.0 dtex, particularly between 0.3 dtex and 4.5 dtex, more particularly between 0.4 dtex and 4.0 dtex, and even more particularly between 0.6 dtex and 3.0 dtex. If the fineness of the hydrophilic cellulose fibers is too low, neps (fiber clumps) are likely to form in the nonwoven fabric, and if it is too high, the tactile 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, fineness adjustment is difficult, so fibers with fineness outside the above ranges may be used.

[0035] The fiber length of the hydrophilic cellulose fibers contained in fiber layer A is not particularly limited and may be, for example, 10 mm or longer. The specific fiber length of the hydrophilic cellulose fibers contained in fiber layer A may be selected according to the manufacturing method of the nonwoven fabric, etc. The relationship between the manufacturing method of the nonwoven fabric (method for producing the fiber layer) and the fiber length is as explained in relation to water-repellent cellulose fibers.

[0036] The fiber layer A may consist of multiple hydrophilic cellulose fibers that differ in one or more of the following: material, fiber length, and fineness.

[0037] Hydrophilic cellulose fibers may be such that, when the sedimentation velocity is measured using the method described for evaluating the water repellency of hydrophobic cellulose fibers, the sample sinks below the water surface within 60 seconds. Hydrophilic cellulose fibers may also be such that, after the sample is dropped onto the water surface in a beaker, they absorb water and sink below the water surface within, for example, 50 seconds, especially within 45 seconds, and more particularly within 30 seconds.

[0038] [Synthetic fiber] Synthetic fibers may consist of one or more thermoplastic resins arbitrarily selected from polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and its copolymers; polyolefin resins such as polypropylene, polyethylene (including 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) mainly composed of propylene, ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers; polyamide resins such as nylon 6, nylon 12, and nylon 66; acrylic resins; engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefins, and their elastomers. Of these, biodegradable resins such as polylactic acid and polybutylene succinate are preferably used when emphasizing the SDGs.

[0039] Alternatively, the synthetic fiber may be a synthetic fiber containing biomass raw materials. Examples of synthetic fibers containing biomass raw materials include biopolypropylene (also known as bioPP), biopolyethylene (also known as bioPE), biopolyethylene terephthalate (also known as bioPET), biopolytrimethylene terephthalate (also known as bioPTT), biopolycarbonate (also known as bioPC), biopolyurethane (also known as bioPU), biopolyamide 11 (also known as bioPA11), biopolyamide 1010 (also known as bioPA1010), biopolyamide 610 (also known as bioPA610), biopolyamide MXD10 (also known as bioMXD10), biopolyamide 11T (also known as bioPA11T), etc. More specifically, these are synthetic fibers manufactured by melt spinning or the like using such biomass raw materials. Synthetic fibers containing biomass raw materials are also preferably used when emphasizing the SDGs.

[0040] Alternatively, the synthetic fiber may be a synthetic fiber containing recycled resin raw materials. Examples of synthetic fibers containing recycled resin raw materials include recycled polypropylene (also called recycled PP), recycled polyethylene terephthalate (also called recycled PET), and recycled nylon. Synthetic fibers containing recycled resin raw materials are also preferably used when emphasizing the SDGs.

[0041] In the following, the resins specifically mentioned also refer to those made from biomass raw materials or recycled resin raw materials, if those materials are provided as such. For example, the term "polypropylene single fiber" includes not only single fibers made from ordinary polypropylene raw materials, but also single fibers made from bio-polypropylene and recycled (recycled) polypropylene single fibers.

[0042] Synthetic fibers may be single fibers whose fiber cross-section consists of a single component (also called a "single section"), and / or composite fibers whose fiber cross-section consists of multiple components (also called "sections"). Composite fibers may be, for example, concentric or eccentric core-sheath type composite fibers, sea-island type composite fibers, side-by-side type composite fibers, or segmented type composite fibers. The fiber cross-section may be circular or non-circular, and non-circular shapes include elliptical, Y-shaped, X-shaped, grid-shaped, multi-lobed, polygonal, and star-shaped. Synthetic fibers may also have a hollow cross-section. In both the case of single fibers and composite fibers, each section constituting the fiber may be made of one type of resin, or a mixture of two or more types of resins.

[0043] When the synthetic fiber is a single fiber, the single fiber may be made of one or more resins selected from the group consisting of the above-mentioned polyolefin resins, polyester resins, polyamide resins, and acrylic resins. More specifically, polyethylene single fibers, polypropylene single fibers, polyethylene terephthalate single fibers, etc., may be used.

[0044] When the synthetic fiber is a composite fiber, two or more components may be arranged such that the thermoplastic resin with the lowest melting point constitutes a portion of the fiber surface. In this case, when heat is applied in the process of producing the nonwoven fabric under conditions that cause the component consisting of the thermoplastic resin with the lowest melting point (hereinafter referred to as the "low-melting-point component") to melt or soften, the low-melting-point component becomes an adhesive component. The combination of resins (first / second) constituting the composite fiber, consisting of a first component which is a thermoplastic resin with a higher melting point and a second component which is a thermoplastic resin with a lower melting point, includes, for example, combinations of polyester resins such as polyethylene terephthalate / polyethylene, polyethylene terephthalate / polypropylene, and polyethylene terephthalate / propylene copolymer and polyolefin resins, as well as combinations of two types of polyolefin thermoplastic resins such as polypropylene / polyethylene and polypropylene / propylene copolymer, and combinations of two types of polyester resins with different melting points.

[0045] Alternatively, the combination of the first and second components may be a combination of biodegradable resins, and such a combination can increase the proportion of biodegradable fibers in fiber layer A. Specifically, by using polylactic acid as the first component and polybutylene succinate as the second component, the synthetic fibers can be made biodegradable.

[0046] The thermoplastic resins exemplified as components of single or composite fibers may contain other components as long as they contain 50% or more by mass of the specifically indicated thermoplastic resin. The specifically indicated thermoplastic resin may contain 80% or more by mass, 90% or more by mass, or the components may substantially consist of the specifically indicated thermoplastic resin. Here, the term "substantially" is used considering that thermoplastic resins usually contain various additives, etc. For example, in the polyethylene terephthalate / polyethylene combination, "polyethylene" may contain other thermoplastic resins and additives, etc., as long as it contains 50% or more by mass of polyethylene. This also applies to the following examples.

[0047] When a synthetic fiber is a concentric or eccentric core-sheath composite fiber in which a thermoplastic resin with a higher melting point constitutes the core component as the first component and a thermoplastic resin with a lower melting point constitutes the sheath component as the second component, the core / sheath combination may be, 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, or polyethylene terephthalate / copolymerized polyester (e.g., polyethylene terephthalate copolymerized with isophthalic acid). These resin combinations may also be used in split-type composite fibers.

[0048] In the case of core-sheath type composite fibers, the composite ratio of core component to sheath component (core component: sheath component) is preferably 80:20 to 20:80 by volume, more preferably 70:30 to 30:70, and even more preferably 60:40 to 40:60.

[0049] In the case of segmented composite fibers, the ratio of the two components (1st:2nd) is preferably 80:20 to 20:80 in volume ratio, more preferably 70:30 to 30:70, and even more preferably 60:40 to 40:60. In the case of segmented composite fibers, the number of segments (i.e., the number of sections in the composite fiber) may be, for example, 4 or more and 32 or less, particularly 4 or more and 20 or less, and more particularly 6 or more and 10 or less.

[0050] In this embodiment, core-sheath type composite fibers (concentric or eccentric) in which the first / second component combination is polylactic acid / polybutylene succinate, polyethylene terephthalate / copolymer polyester, polypropylene / polyethylene, or polyethylene terephthalate / polyethylene can be preferably used as synthetic fibers. When used as adhesive fibers, these fibers exhibit adhesion at relatively low temperatures (110°C to 130°C) and make the texture of the nonwoven fabric flexible after bonding.

[0051] The fineness of the synthetic fibers 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, and even more particularly 1.7 dtex or more and 5.0 dtex or less. If the fineness of the synthetic fibers is too low, the strength of the nonwoven fabric will be low and it may be prone to stretching. Also, the fiber density on the surface of the nonwoven fabric will be high, making it prone to clogging with dirt and reducing its dirt-collecting ability. If the fineness of the synthetic fibers is too high, the nonwoven fabric may feel hard to the touch. If the nonwoven fabric is prone to stretching, for example, when the nonwoven fabric is attached to a jig for wiping work, sagging and wrinkles may occur when attaching it to the jig. Also, the fiber density on the surface of the nonwoven fabric will be low, and dirt that has been collected may fall off.

[0052] In particular, if the synthetic fiber is a split-type composite fiber, the split-type composite fiber may have a fineness of 1.0 dtex or more and 4.0 dtex or less before splitting, and may yield a synthetic fiber with a fineness of 0.1 dtex or more and less than 1.0 dtex after splitting.

[0053] The fiber length of the synthetic fiber is not particularly limited and may be appropriately selected depending on the manufacturing method of the nonwoven fabric. For example, when fiber layer A is manufactured by creating a card web in the manufacturing of the nonwoven fabric, the synthetic fiber may be a short fiber. The fiber length of this short fiber may be, for example, 10 mm to 100 mm, particularly 20 mm to 75 mm, and more particularly 30 mm to 65 mm. Alternatively, when fiber layer A is manufactured by the air-lay method, the fiber length may be, for example, 2 mm to 20 mm.

[0054] Synthetic fibers are generally hydrophobic, for example, having an official moisture content of less than 5%. In this embodiment, the synthetic fibers may be hydrophilized. Examples of hydrophilization treatments include corona discharge treatment, sulfonation treatment, graft polymerization treatment, kneading of hydrophilizing agents into the fibers, and application of durable oils.

[0055] In the above, hydrophilic cellulose fibers and synthetic fibers were described as other fibers, but other fibers are not limited to these. Other fibers may include, for example, natural fibers such as silk and wool.

[0056] (Fibers that make up the fiber layer other than fiber layer A) This embodiment is a nonwoven fabric comprising a fiber layer A containing water-repellent cellulose fibers in a predetermined proportion, wherein the fiber layer A forms at least one surface of the nonwoven fabric. Therefore, as will be described later, the nonwoven fabric of this embodiment may include fiber layers other than fiber layer A. The fibers constituting the fiber layers other than fiber layer A are not particularly limited and may be one or more fibers selected from the water-repellent cellulose fibers, hydrophilic cellulose fibers, synthetic fibers, and natural fibers described above.

[0057] If a fiber layer other than fiber layer A is an intermediate fiber layer located between the two fiber layers A, the fibers constituting the intermediate fiber layer may be hydrophilic cellulose fibers with a fiber length of less than 10 mm. By including a predetermined proportion or more of short hydrophilic cellulose fibers in the intermediate fiber layer, when the nonwoven fabric is used as a wet wiper, the intermediate fiber layer acts as a "tank" to hold liquid, and in combination with the use of fiber layer A, it makes it possible to release small amounts of liquid over a long period of time. Examples of hydrophilic cellulose fibers with a fiber length of less than 10 mm include pulps such as mechanical pulp, recycled pulp, and chemical pulp, as well as recycled fibers, melt-spun cellulose fibers, and semi-synthetic fibers, which can be cut to the desired fiber length during the manufacturing process.

[0058] In this embodiment, pulp is preferably used as the hydrophilic cellulose fiber contained in the intermediate fiber layer. The pulp may be manufactured using conventional methods with coniferous or deciduous wood. Generally, the fineness of the pulp fibers is about 1.0 dtex to 4.0 dtex, and the fiber length is about 0.8 mm to 4.5 mm.

[0059] Pulp is readily accepted by consumers because it has a proven track record of being used as a material for hygiene products, and because it is biodegradable, it is preferably used as a material for disposable wipers that are discarded after use. Furthermore, when wood-derived pulp is used to manufacture nonwoven fabrics by the water entanglement method, as described later, if hydrophilic cellulose fibers are included in fiber layer A, it promotes entanglement between fibers.

[0060] Alternatively, fiber layers other than fiber layer A may be mesh sheets, as described later. When a mesh sheet is included as a fiber layer other than fiber layer A, the fibers constituting the fiber layer are monofilaments made of synthetic resin, strands made by twisting fibers together, or a net (or a filamentous material extruded into a net shape) made of undrawn or drawn filaments obtained by extrusion molding.

[0061] Alternatively, the fiber layers other than fiber layer A may be meltblown nonwovens or long-fiber nonwovens (also called spunbond nonwovens), as described later, and may be air-through nonwovens, point-bond nonwovens, or wet-laid nonwovens formed from short fibers. When these nonwovens are included as fiber layers other than fiber layer A, the fibers constituting said fiber layers are synthetic fibers or regenerated fibers.

[0062] (Composition of nonwoven fabric) Next, the structure of the nonwoven fabric of this embodiment will be described. The nonwoven fabric of this embodiment is a nonwoven fabric having a first surface and a second surface opposite to it, and based on the total mass of the nonwoven fabric, it contains water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and other fibers in a proportion of more than 25% by mass and 90% by mass or less. At least one of the first surface and the second surface is the surface of a fiber layer A containing the water-repellent cellulose fibers in a proportion of 10% by mass or more and the other fibers in a proportion of 90% by mass or less. It is formed by the entanglement of fibers, which causes them to become one.

[0063] In this embodiment, the nonwoven fabric is configured such that the surface of the fiber layer A, which contains water-repellent cellulose fibers in a predetermined proportion, becomes at least one of the two main surfaces of the nonwoven fabric, namely the first surface and the second surface, thereby ensuring excellent sustained release of liquids and dirt collection capabilities.

[0064] The proportion of water-repellent cellulose fibers in fiber layer A is 10% by mass or more, particularly 30% to 90% by mass, and more particularly 40% to 80% by mass. As described above, water-repellent cellulose fibers absorb liquid from the cut surface and swell, and this swelling reduces their rigidity, making them somewhat more susceptible to deformation due to wiping pressure compared to synthetic fibers. Furthermore, as will be described later, when water-repellent cellulose fibers are entangled by a high-pressure fluid flow (especially a high-pressure water flow), the water-repellent surface of the fibers suppresses excessive entanglement and facilitates the formation of appropriate voids between the fibers. Therefore, by positioning water-repellent cellulose fibers on the surface that becomes the wiping surface of the wiper, it becomes easier to capture dirt with slightly larger solid dimensions due to the deformation of the fibers, and it becomes possible to retain an appropriate amount of liquid in the voids between the fibers and release it gradually.

[0065] If the proportion of water-repellent cellulose fibers in fiber layer A is less than 10% by mass, the dirt-collecting ability and the sustained release of liquid may be insufficient. The proportion of water-repellent cellulose fibers in fiber layer A may be 100% by mass, meaning that fiber layer A may consist solely of water-repellent cellulose fibers. However, as the proportion of water-repellent cellulose fibers in fiber layer A increases, the water-repellency of the fibers increases, making entanglement by high-pressure liquid flow less likely. Additionally, the strength of the fibers themselves is not as high as that of synthetic fibers, which may lead to a decrease in the strength of the nonwoven fabric or an increase in lint shedding during wiping.

[0066] Fiber layer A contains, as a remainder, other fibers besides water-repellent cellulose fibers. Therefore, the proportion of other fibers is 90% by mass or less. The other fibers are not particularly limited and may be synthetic fibers or hydrophilic cellulose fibers. Alternatively, the other fibers may include both synthetic fibers and hydrophilic cellulose fibers.

[0067] Synthetic fibers are preferred because they improve the mechanical strength of nonwoven fabrics and impart rigidity to them. Furthermore, by using synthetic fibers as adhesive fibers and melting or softening some of their components to bond the fibers together, the mechanical strength and dimensional stability of the nonwoven fabric are further improved, and surface fuzzing is also suppressed. In addition, since synthetic fibers are generally hydrophobic, together with water-repellent cellulose fibers, they form appropriate interfiber voids in the nonwoven fabric, allowing liquids to be adequately retained and gradually released.

[0068] When fiber layer A contains synthetic fibers as other fibers, the proportion of synthetic fibers in fiber layer A may be greater than 0% by mass and less than or equal to 35% by mass, particularly between 5% by mass and 30% by mass, and more particularly between 10% by mass and 25% by mass. If the proportion of synthetic fibers exceeds 35% by mass, the proportion of water-repellent cellulose fibers decreases accordingly, making it difficult to obtain the effects of including water-repellent cellulose fibers (especially improved dirt collection). Also, if the proportion of synthetic fibers is large, the entanglement of fibers may not be sufficient when entangled by high-pressure fluid flow, and the interfiber voids in the nonwoven fabric may become excessively large. Since liquid held in such large interfiber voids is easily released once by wiping pressure, if the proportion of synthetic fibers is too large, the sustained release of liquid from the nonwoven fabric may decrease.

[0069] When fiber layer A contains two or more types of synthetic fibers, at least one type of synthetic fiber may be used as an adhesive fiber, and at least one type of synthetic fiber may exist as a non-adhesive fiber. Here, the non-adhesive fiber is one that maintains its fiber shape without melting or softening at the temperature at which the adhesive component of the adhesive fiber melts or softens to bond the fibers together. Therefore, whether a fiber is adhesive or non-adhesive is determined by the resin that makes up each fiber and the conditions (heating temperature) when manufacturing the nonwoven fabric. For example, a synthetic fiber with polyethylene as one component may be subjected to a heat treatment of about 135°C and used as an adhesive fiber with polyethylene as the adhesive component, while a single synthetic fiber made of polypropylene or polyethylene terephthalate may be used as a non-adhesive fiber.

[0070] By using both adhesive and non-adhesive fibers, the non-adhesive fibers are incorporated into the nonwoven fabric while maintaining their fiber shape. As non-adhesive fibers, being synthetic fibers, are generally hydrophobic as described above, they are less prone to entanglement even when subjected to entanglement treatment with aqueous fluids, and exist in the nonwoven fabric in a relatively free state. Therefore, compared to using only adhesive fibers, the dirt collection performance tends to improve. Furthermore, the bonding of fibers by adhesive fibers tends to inhibit deformation of the fibers and interfiber voids due to wiping pressure, so the presence of non-adhesive fibers can mitigate this. In addition, even when the nonwoven fabric is impregnated with liquid, non-adhesive fibers do not easily absorb liquid and are less likely to experience a decrease in fiber strength due to liquid absorption or swelling, unlike cellulose fibers. Therefore, 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 collection performance and ease of use.

[0071] As described above, when synthetic fibers are incorporated into fiber layer A, the synthetic fibers may be 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. Such synthetic fibers are preferably used together with water-repellent cellulose fibers from the viewpoint of SDGs.

[0072] When hydrophilic cellulose fibers are included as other fibers, the hydrophilic cellulose fibers themselves are absorbent, allowing them to store liquid, which can then be released in the initial stages of wiping. Therefore, the use of hydrophilic cellulose fibers is suitable for applications where it is desirable to release a relatively large amount of liquid in the initial stages of wiping (for example, applications where it is desirable to first "loosen" stubborn dirt with liquid). Furthermore, hydrophilic cellulose fibers exhibit excellent entanglement when the fibers are entangled by a high-pressure fluid flow. Therefore, by using hydrophilic cellulose fibers, it is possible to increase the degree of entanglement between fibers, thereby improving the strength of the nonwoven fabric and / or preventing shedding and fuzzing. In particular, when the nonwoven fabric of this embodiment does not contain any fiber layers other than fiber layer A, and the fibers are entangled by a high-pressure fluid flow, it is preferable to include hydrophilic cellulose fibers as other fibers to ensure entanglement between fibers.

[0073] When fiber layer A contains hydrophilic cellulose fibers as other fibers, the proportion of hydrophilic cellulose fibers in fiber layer A may be greater than 0% by mass and less than or equal to 75% by mass, particularly 10% by mass or more and less than or equal to 60% by mass, and more particularly 20% by mass or more and less than or equal to 50% by mass. Hydrophilic cellulose fibers, like hydrophobic cellulose fibers, are swellable and easily deform under wiping pressure when the nonwoven fabric is used as a wet wipe, so their inclusion does not significantly reduce the dirt-collecting ability exhibited by hydrophobic cellulose fibers. However, if the proportion of hydrophilic cellulose exceeds 75% by mass, the liquid held by the hydrophilic cellulose fibers tends to be released all at once at the start of the wiping process, excessively wetting the wiping surface and making it difficult to perform wiping smoothly.

[0074] The fiber layer A may contain both hydrophilic cellulose fibers and synthetic fibers as other fibers. In this case, the proportion of hydrophilic cellulose fibers in fiber layer A may be 0% to 75% by mass, particularly 10% to 60% by mass, and the proportion of synthetic fibers in fiber layer A may be 0% to 30% by mass, particularly 5% to 25% by mass. When hydrophilic cellulose fibers and synthetic fibers are included within this range, the nonwoven fabric can retain liquid appropriately while increasing the mechanical strength of the nonwoven fabric and suppressing the amount of lint shedding during wiping.

[0075] The nonwoven fabric of this embodiment may be a single-layer structure consisting only of fiber layer A, or a laminated structure consisting of fiber layer A and one or more other fiber layers A. The other fiber layers are fiber layers consisting of fibers other than water-repellent cellulose, or fiber layers in which the proportion of water-repellent cellulose fiber layers is outside the above range. The other fiber layers may be, for example, meltblown nonwoven fabrics, long-fiber nonwoven fabrics (also called spunbond nonwoven fabrics), air-through nonwoven fabrics or point-bond nonwoven fabrics formed of short fibers, or wet-laid nonwoven fabrics.

[0076] Alternatively, the other fiber layers may be mesh sheets. Mesh sheets include scrim and nets made by biaxial stretching of thermoplastic resins. For example, ConwedNet® manufactured by CONWED GLOBAL NETTING SOLUTIONS, Inc. in the United States may be used as mesh sheets. Mesh sheets tend to have relatively large voids while exhibiting high mechanical properties, and therefore integrate well with fiber layer A to reinforce the nonwoven fabric. Furthermore, by using mesh sheets, when entanglement of fibers with a high-pressure fluid flow, it is possible to lower the pressure of the liquid flow and integrate the fiber layers.

[0077] The nonwoven fabric of this embodiment, whether single-layer or laminated, contains water-repellent cellulose fibers in a proportion of 10% to less than 75% by mass, based on the total mass of the nonwoven fabric, and other fibers in a proportion of more than 25% to 90% by mass. If the proportion of water-repellent cellulose fibers to the entire nonwoven fabric is less than 10% by mass, it is not possible to form fiber layer A, or the proportion of fiber layer A to the entire nonwoven fabric becomes too small, which tends to reduce the dirt-collecting ability and liquid-releasing ability. If water-repellent cellulose fibers account for 75% or more by mass of the entire nonwoven fabric, the strength of the nonwoven fabric may decrease, and / or fuzzing may easily occur on the surface of the nonwoven fabric. The proportion of water-repellent cellulose fibers to the entire nonwoven fabric may be particularly 10% to 70% by mass, and more particularly 20% to 60% by mass.

[0078] When the nonwoven fabric of this embodiment has a laminated structure, the proportion of water-repellent cellulose fibers in the entire nonwoven fabric may be determined according to the other fiber layers and the configuration of the laminated structure. For example, as will be described later, the nonwoven fabric of this embodiment is assumed to have a first fiber layer, a second fiber layer, and an intermediate fiber layer disposed between the first and second fiber layers, where both the first and second fiber layers are fiber layer A. In this configuration, if the intermediate fiber layer contains hydrophilic fibers or other materials that easily retain water and do not easily release water even when wiping pressure is applied, the proportion of water-repellent cellulose fibers can be reduced. On the other hand, if the intermediate fiber layer is extremely thin or contains large voids (for example, a mesh sheet or a nonwoven fabric in which fibers are bonded together), the proportion of water-repellent cellulose fibers may be increased. As a result, when wiping pressure is applied, the intermediate fiber layer may not be able to retain the liquid, and the liquid that has moved to the side of the first and second fiber layers may be prevented from moving to the nonwoven fabric surface by the water-repellent cellulose fibers, thereby suppressing excessive release of liquid.

[0079] More specifically, if the intermediate fiber layer is a wet-laid nonwoven fabric containing hydrophilic cellulose fibers, the proportion of water-repellent cellulose fibers in the entire nonwoven fabric may be 10% by mass or more and 75% by mass or less, particularly 10% by mass or more and 70% by mass or less, and more particularly 20% by mass or more and 60% by mass or less. If the intermediate fiber layer is a nonwoven fabric containing synthetic fibers and the fibers are bonded together (for example, an air-through nonwoven fabric), the proportion of water-repellent cellulose fibers in the entire nonwoven fabric may be 15% by mass or more and 75% by mass or less, particularly 25% by mass or more and 70% by mass or less, and more particularly 30% by mass or more and 65% by mass or less. If the intermediate fiber layer is a mesh sheet, the proportion of water-repellent cellulose fibers in the entire nonwoven fabric may be 15% by mass or more and 75% by mass or less, particularly 25% by mass or more and 70% by mass or less, and more particularly 30% by mass or more and 65% by mass or less.

[0080] In this embodiment, the nonwoven fabric has a laminated structure, comprising a first fiber layer, a second fiber layer, and an intermediate fiber layer positioned between the first and second fiber layers, wherein both the first and second fiber layers may be fiber layer A. Such a nonwoven fabric allows both surfaces to be used as wiping surfaces exhibiting excellent wiping performance. Furthermore, by appropriately selecting the composition of the intermediate fiber layer, it is possible to adjust the overall liquid retention capacity and mechanical properties of the nonwoven fabric.

[0081] The intermediate fiber layer may be one or more selected from, for example, air-through nonwoven fabrics and point-bonded nonwoven fabrics formed by short fibers, as well as melt-blown nonwoven fabrics, long-fiber nonwoven fabrics, wet-laid nonwoven fabrics, and mesh sheets. If the intermediate fiber layer is an air-through nonwoven fabric, the air-through nonwoven fabric may be made of synthetic fibers with a fineness of 1.0 dtex to 8.0 dtex, particularly 1.5 dtex to 6.0 dtex. If the intermediate fiber layer is a melt-blown nonwoven fabric, the melt-blown nonwoven fabric may be made of synthetic fibers with a fineness of 0.005 dtex to 1.0 dtex, particularly 0.007 dtex to 0.7 dtex. If the intermediate layer is a long-fiber nonwoven fabric, the long-fiber nonwoven fabric may be made of synthetic fibers with a fineness of 0.5 dtex to 7.0 dtex, particularly 1.0 dtex to 4.0 dtex.

[0082] The long-fiber nonwoven fabric may be a spunbond nonwoven fabric, a sheet made by combining a sheet with threads aligned in the longitudinal direction and a sheet with threads aligned in the transverse direction, or a sheet made by laminating and integrating two or more net-like webs made by splitting and stretching a film. Examples of such sheets include Miraif® and Warif® manufactured by JX ANCI Corporation.

[0083] In this embodiment, the intermediate layer may be a wet-laid nonwoven fabric containing hydrophilic cellulose fibers, particularly a wet-laid nonwoven fabric (or tissue) made of pulp. Since a wet-laid nonwoven fabric containing hydrophilic cellulose fibers has excellent water absorption and can hold a large amount of liquid, it functions as a tank for accumulating liquid (for example, cleaning solution contained in a wet wipe) in the nonwoven fabric, and when the nonwoven fabric is used as a wet wipe, it can supply liquid to the wiping surface for a long period of time during the wiping process. Furthermore, when the fibers are entangled with a high-pressure liquid flow, the hydrophilic cellulose fibers are positioned between the two fiber layers A, allowing them to entangle well with the fibers constituting the fiber layers A, thereby improving the overall strength of the nonwoven fabric.

[0084] Alternatively, the intermediate fiber layer may be a mesh sheet. As described above, a mesh sheet can reduce the influence on fiber entanglement and effectively reinforce the entire nonwoven fabric. Therefore, for example, if hydrophilic cellulose fibers are included in the first fiber layer and / or second fiber layer, when the fibers are entangled by a high-pressure fluid flow, the hydrophilic cellulose fibers promote entanglement through the mesh of the mesh sheet, thereby improving the mechanical properties of the nonwoven fabric.

[0085] If the mesh sheet has regular openings (for example, rectangles or squares defined by filaments), the dimensions of the openings may be, for example, 3 mm or more, particularly 4 mm or more, and more particularly 5 mm or more. The upper limit of the opening dimensions may be, for example, 15 mm, particularly 12 mm. The dimensions of the openings are the length of the longest line segment connecting any two points on the contour defining the opening. If the dimensions of the openings are too small, the entanglement between the upper and lower fiber layers may be insufficient, especially when the nonwoven fabric is configured with a first fiber layer and a second fiber layer positioned above and below the mesh sheet. As a result, delamination may occur more easily. A mesh sheet with regular openings may have an opening ratio of 50% to 99%, particularly 60% to 98%, and more particularly 70% to 97%. When the opening ratio is within this range, the entanglement with the fibers tends to be good, and it is easier to ensure good entanglement between fibers when fiber layers are located on both sides.

[0086] The first and second fiber layers may both be fiber layer A, and therefore the two fiber layers may be the same or different in terms of fiber type, fiber mixing ratio, basis weight, and manufacturing form of the fiber layer (type of fiber web). For example, the proportion of water-repellent cellulose fibers may be different between the two fiber layers, so that the surfaces of the two fiber layers can be used for different purposes (e.g., wiping the floor surface in a dining room and wiping the floor surface in a bathroom).

[0087] In the nonwoven fabric of this embodiment, the basis weight of the fiber layer A is, for example, 35 g / m². 2 More than 100g / m2 It may have the following basis weights, particularly 40 g / m 2 or more and 95 g / m 2 or less, more particularly 45 g / m 2 or more and 90 g / m 2 or less, even more particularly 50 g / m 2 or more and 85 g / m 2 or less.

[0088] When the fiber layer A exists as the first fiber layer and the second fiber layer, the first fiber layer and the second fiber layer may each have, for example, 10 g / m 2 or more and 50 g / m 2 or less, particularly 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, even more particularly 17.5 g / m 2 or more and 40 g / m 2 or less.

[0089] Also, the intermediate fiber layer that constitutes the non-woven fabric together with the first and second fiber layers may have, 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, more particularly 7 g / m 2 or more and 40 g / m 2 or less, even more particularly 8 g / m 2 or more and 35 g / m 2 or less.

[0090] In a nonwoven fabric comprising a first and second fiber layer and an intermediate fiber layer, when the basis weight of the entire nonwoven fabric is set to 1, the ratio of the basis weight of the intermediate fiber layer to the total basis weight (intermediate fiber layer / total nonwoven fabric) may be, for example, 0.05 or more and 1 or less, particularly 0.10 or more and 0.80 or less, and more particularly 0.15 or more and 0.60 or less. If the proportion of the intermediate fiber layer to the nonwoven fabric is too large, the effect of fiber layer A may not be obtained, and the function of the intermediate fiber layer may be excessively expressed, resulting in excessive rigidity of the nonwoven fabric (when the intermediate fiber layer is a mesh sheet), or liquid may be released easily all at once, reducing sustained release (when the intermediate fiber layer is made of hydrophilic cellulose fibers), and other undesirable conditions may arise. On the other hand, if the proportion of the basis weight of the intermediate fiber layer is too small, the effect of providing the intermediate fiber layer may not be fully obtained.

[0091] The overall basis weight of the nonwoven fabric in this embodiment may be appropriately selected depending on the application. For example, the overall basis weight of the nonwoven fabric in this embodiment is 30 g / m². 2 More than 100g / m 2 The following weights may be used, particularly 35 g / m². 2 More than 95g / m 2 The following weights may be used, and more particularly 40 g / m² 2 More than 90g / m 2 The following basis weights may be used, and more particularly 45 g / m² 2 More than 85g / m 2 The following measurements may be used.

[0092] The nonwoven fabric of this embodiment may have a tensile strength in the MD direction when dry 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, and more particularly 40 N / 5 cm or more and 190 N / 5 cm or less. If the tensile strength in the MD direction when dry is too low, the product may break during processing. If the tensile strength in the MD direction when dry is too high, the nonwoven fabric tends to become rigid. If a rigid nonwoven fabric is used as a wiper, it may scratch the object being wiped.

[0093] The nonwoven fabric of this embodiment may have a tensile strength in the CD direction when dry, for example, 3N / 5cm to 100N / 5cm, particularly 4N / 5cm to 95N / 5cm, and more particularly 5N / 5cm to 90N / 5cm. If the tensile strength in the CD direction when dry is too low, it may break during use. If the tensile strength in the CD direction when dry is too high, the nonwoven fabric tends to become rigid. If a rigid nonwoven fabric is used as a wiper, it may scratch the object being wiped.

[0094] The nonwoven fabric of this embodiment may have an elongation rate in the MD direction when dry of, for example, 20% to 100%, particularly 25% to 95%, and more particularly 30% to 90%. Furthermore, the nonwoven fabric of this embodiment may have an elongation rate in the CD direction when dry of, for example, 10% to 200%, particularly 15% to 195%, and more particularly 20% to 190%. If the elongation rate in the MD or CD direction when dry is too low, the nonwoven fabric may break with slight deformation, reducing its flexibility when attached to a jig. If the elongation rate in the MD or CD direction when dry is too high, it becomes difficult to handle during product processing.

[0095] The nonwoven fabric of this embodiment may have a 10% elongation stress in the MD direction when dry, for example, 3N / 5cm to 60N / 5cm, more particularly 4N / 5cm to 55N / 5cm, and more particularly 5N / 5cm to 60N / 5cm. Furthermore, the nonwoven fabric of this embodiment may have a 10% elongation stress in the CD direction when dry, for example, 0.5N / 5cm to 30N / 5cm, more particularly 0.6N / 5cm to 25N / 5cm, and more particularly 0.7N / 5cm to 20N / 5cm. If the 10% elongation stress in the MD or CD direction when dry is too low, the product becomes difficult to handle during processing. If the 10% elongation stress in the MD or CD direction when dry is too high, the fibers tend to move less easily during wiping, which can reduce the dirt collection efficiency.

[0096] (Manufacturing method for nonwoven fabrics) Next, the method for manufacturing the nonwoven fabric of this embodiment will be described. The laminated nonwoven fabric of this embodiment is, for example, To produce a fiber web A 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 If necessary, prepare a fiber web other than fiber web A (for convenience, let's call it "fiber web B"). To fabricate a laminated fiber web by laminating fiber web A and fiber web B, and The laminated fiber web is subjected to a treatment that causes the fibers to intertwine. Includes, When preparing fiber webs A and B, the types and proportions of fibers constituting each fiber web, as well as the basis weight of each fiber web, are selected based on the total mass of the laminated fiber web, such that the proportion of water-repellent cellulose fibers is 10% to 75% by mass, and the proportion of other fibers is over 25% to 90% by mass. It can be manufactured by the manufacturing method. If fiber web B is not produced (i.e., when producing a single-layer nonwoven fabric), fiber web A is prepared to contain water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and other fibers in a proportion of more than 25% by mass and less than or equal to 90% by mass.

[0097] Two fiber webs A ("fiber web A1" and "fiber web A2") may be prepared, and these fiber webs may be laminated so that fiber web B is placed between these two fiber webs. If such laminated webs are subjected to a process that entangles the fibers, a nonwoven fabric can be obtained in which an intermediate fiber layer is located between the first fiber layer and the second fiber layer, which constitute fiber layer A.

[0098] The types and weights of the fibers contained in fiber webs A, A1, and A2, as well as fiber web B, are as described in relation to fiber layer A, the first fiber layer, and the second fiber layer, and are therefore omitted here. The types and weights of the fibers contained in fiber web B are as described in relation to the other fiber layers and the intermediate fiber layer, and are therefore omitted here.

[0099] Fiber webs A, A1, and A2 can be manufactured 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, and wet-machine webs. When manufacturing fiber webs A1 and A2, their forms may be different from each other. If fiber webs A1 and A2 are card webs, a nonwoven fabric suitable for wiper applications is easily obtained, which has interfiber voids suitable for collecting dirt.

[0100] The form of fiber web B is also not limited and may be any of the above forms exemplified in relation to fiber webs A, A1, and A2. When fiber web B is made of pulp, fiber web B may be a wet papermaking web or an airlaid web. Alternatively, fiber web B may be a nonwoven fabric provided (e.g., sold) as a wet papermaking nonwoven fabric, a meltblown nonwoven fabric, or a long-fiber nonwoven fabric. In this case, strictly speaking, fiber web B is not a web with a small degree of fiber entanglement, but rather a nonwoven fabric in which the fibers are integrated. Alternatively, a mesh sheet may be used as fiber web B. In this case as well, strictly speaking, fiber web B is not a web.

[0101] The laminated fiber web or fiber web A is subjected to a process that entangles the fibers. The process of entangling the fibers is, for example, needle punching or high-pressure fluid flow (especially water flow) entanglement. In high-pressure fluid flow processing, the high-pressure fluid is, for example, a high-pressure gas such as compressed air, a high-pressure liquid such as high-pressure water, and high-pressure water vapor. In the manufacture of nonwoven fabrics, water flow entanglement processing using high-pressure water as the high-pressure fluid is often used, and in this embodiment as well, water flow entanglement processing is preferably used from the viewpoint of ease of implementation. Below, the entanglement processing when high-pressure water (hereinafter also simply referred to as "water flow") is used as the high-pressure fluid will be described.

[0102] 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 manufacture of nonwoven fabrics, water flow entanglement processing using high-pressure water as the high-pressure fluid is often used, and in this embodiment as well, water flow entanglement processing is preferably used from the viewpoint of ease of implementation. Below, a manufacturing method when high-pressure water (hereinafter also simply referred to as "water flow") is used as the high-pressure fluid will be described.

[0103] The water entanglement treatment is performed by placing a laminated fiber web or fiber web A on a support and spraying a columnar stream of water onto it. For example, the support is preferably a plain weave support with a mesh size of 80 or more and 100 or less. The water entanglement treatment may be performed by spraying a water stream with a water pressure of 1 MPa or more and 15 MPa or less onto the front and back surfaces of the laminated fiber web 1 to 5 times each from a nozzle provided with 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. The water pressure is preferably 1 MPa or more and 10 MPa or less, and more preferably 1 MPa or more and 7 MPa or less.

[0104] Entanglement by water flow treatment proceeds more easily the higher the hydrophilicity of the fibers. When a fiber web consisting only of hydrophilic fibers is subjected to water flow entanglement treatment, a nonwoven fabric with a high fiber density and tightly entangled fibers tends to be obtained. In this embodiment, water-repellent cellulose fibers are included in the fiber web, and these water-repellent cellulose fibers are less susceptible to entanglement by water flow entanglement treatment. Therefore, compared to cases where hydrophilic fibers are used, the resulting nonwoven fabric tends to have larger interfiber voids and a relatively greater degree of fiber freedom. As a result, when the resulting nonwoven fabric is used as a wiper, the water-repellent cellulose fibers themselves are easily deformable, which helps to retain the wiped dirt within the wiper. In addition, the interfiber voids formed by the water-repellent cellulose fibers are suitable for accumulating liquid and releasing it appropriately.

[0105] If any one or more fiber webs contain adhesive fibers, the laminated fiber web or fiber web A may be subjected to an adhesive treatment to obtain a nonwoven fabric in which the fibers are bonded to each other. The adhesive treatment may be a heat bonding treatment, or bonding by electron beam irradiation, or ultrasonic welding. With heat treatment, the adhesive fibers (e.g., low-melting-point components of composite fibers) melt or soften upon heating during the heat treatment, allowing the fibers constituting the laminated fiber web or fiber web A to bond to each other.

[0106] Heat treatment may include, for example, hot air processing, hot roll processing (hot embossing roll processing), or heat treatment using infrared radiation. Hot air processing may be carried out using a device that blows hot air at a predetermined temperature onto a laminated fiber web, such as a hot air penetration heat treatment machine or a hot air blowing heat treatment machine.

[0107] The heat treatment temperature (for example, the temperature of the hot air) may be the temperature at which the component constituting the adhesive fiber, which 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, if 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 if polybutylene succinate is used as the adhesive component, the heat treatment temperature may be 120°C to 133°C.

[0108] (Wipers) 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 is. Alternatively, a wiper may be made by laminating another sheet-like material (nonwoven fabric, film, or sheet) to one surface of the nonwoven fabric of this embodiment. The wiper may be held by hand and used like a rag, or it may be attached to a jig with a wiper attachment part at the end of a rod-shaped object.

[0109] The wiper may be for people or for objects. The nonwoven fabric of this embodiment is particularly suitable for use as an object wiper. The object-oriented wiper may be used for wiping and cleaning floors, kitchens, toilets, bathtubs, furniture, vehicles, walls, screens, and windows. The nonwoven fabric of this embodiment uses water-repellent cellulose fibers, making it suitable for wiping and collecting relatively large solid particles of dirt (food crumbs, hair), and is therefore particularly suitable for wiping and cleaning areas prone to such dirt, such as the floors of dining rooms, living rooms, and bathrooms, the floors of restaurants and other shops, and the floors of factories and workshops. The object-oriented wiper may be impregnated with, for example, water or an aqueous solution containing a cleaning component in an impregnation amount of 100 to 1000 parts by mass per 100 parts by mass 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 per 100 parts by mass of the nonwoven fabric.

[0110] Wipers for personal use may be used to wipe away dirt, cosmetics, or medications that have adhered to a person's body. For example, wipers for personal use may be impregnated with water or an aqueous solution containing a cleaning agent in an impregnation amount of 100 to 1000 parts by mass per 100 parts by mass of nonwoven fabric. More specifically, wipes for personal use impregnated with liquid may be provided as, for example, hand wipes, baby wipes, menstrual blood wipes, makeup remover wipes, facial cleansing wipes, antiperspirant wipes, and nail removers.

[0111] In all cases, the wiper is used so that the wiping surface is the surface of fiber layer A. The water-repellent cellulose fibers contained in fiber layer A deform under wiping pressure, allowing not only fine powdery dirt but also slightly larger dirt particles to be wiped and collected effectively. Furthermore, when the wiper is a wet wiper, the appropriate interfiber voids formed by the water-repellent cellulose fibers provide good sustained release of liquid, and the amount of liquid released during wiping is kept relatively uniform, thus reducing uneven wiping (differences in how dirt is removed) caused by differences in the amount of liquid released. [Examples]

[0112] The following fibers were prepared for use in this embodiment. • Water-repellent cellulose fiber 1 (in the table, "Water-repellent rayon 1.7T"): 1.7 dtex fineness, 40 mm fiber length, viscose rayon (product name: EcoReperus, manufactured by Daiwabo Rayon Co., Ltd.) with the fiber surface treated with a non-fluorine water-repellent agent. To evaluate the water repellency of this fiber, the initial and post-wash settling rates were measured using the method described above. In both measurements, the sample did not settle even after 10 minutes, and almost the entire sample floated on the water surface. The official moisture content of this fiber was 12.8%, and the secondary swelling degree was 53.1% (average of four measurements). • Water-repellent cellulose fiber 2 (in the table, "Water-repellent Lyocell 1.7T"): Fineness 1.7 dtex, fiber length 38 mm, lyocell with a water-repellent treatment on the fiber surface (product name: Lyocell Dry, manufactured by Lenzing). To evaluate the water repellency of this fiber, the initial and post-wash settling rates were measured using the method described above. In both measurements, the sample did not settle even after 10 minutes, and almost the entire sample floated on the water surface. The official moisture content of this fiber was 11.3%, and the secondary swelling degree was 71.0% on average from four measurements. • Water-repellent cellulose fiber 3 (referred to as "Water-repellent rayon 1.0T" in the table): 1.0 dtex fineness, 40 mm fiber length, viscose rayon (product name: EcoReperus, manufactured by Daiwabo Rayon Co., Ltd.) with the fiber surface treated with a non-fluorine water-repellent agent. To evaluate the water repellency of this fiber, the initial and post-wash settling rates were measured using the method described above. In both measurements, the sample did not settle even after 10 minutes, and almost the entire sample floated on the water surface. The official moisture content of this fiber was 13.2%, and the secondary swelling degree was 58.2% (average of four measurements). • Water-repellent cellulose fiber 4 (referred to as "Water-repellent rayon 3.3T" in the table): 3.3 dtex fineness, 40 mm fiber length, viscose rayon (product name: EcoReperus, manufactured by Daiwabo Rayon Co., Ltd.) with the fiber surface treated with a non-fluorine water-repellent agent. To evaluate the water repellency of this fiber, the initial and post-wash settling rates were measured using the method described above. In both measurements, the sample did not settle even after 10 minutes, and almost the entire sample floated on the water surface. The official moisture content of this fiber was 13.0%, and the secondary swelling degree was 58.8% (average of four measurements). • Water-repellent cellulose fiber 5 (referred to as "water-repellent cotton" in the table): Fineness 1.0 dtex to 5.0 dtex, fiber length 10 mm to 60 mm, cotton with a water-repellent surface (product name: Hydri, manufactured by Bernhardt). To evaluate the water repellency of this fiber, the initial and post-wash sedimentation rates were measured using the method described above. In the initial sedimentation rate measurement, the sample did not sink even after 10 minutes, and almost the entire sample floated on the water surface. The sedimentation rate after washing was 26 seconds. The official moisture content of this fiber was 7.3%, and the secondary swelling degree was 39.3% (average of four measurements).

[0113] • Hydrophilic cellulose fiber A (labeled "Rayon 1.7T" in the table): Viscose rayon with a fineness of 1.7 dtex and a fiber length of 40 mm (product name: Corona, manufactured by Daiwabo Rayon Co., Ltd.). When the water repellency (hydrophilicity) of this fiber was evaluated using the method described above, the sedimentation velocity was 7 seconds. • Synthetic fiber a (in the table, "PLA / PBS2.4T"): A core-sheath composite fiber with a fineness of 2.4 dtex and a fiber length of 51 mm, consisting of a core component of polylactic acid and a sheath component of polybutylene succinate (product name: Miracle Fiber KK-PL, manufactured by Yamato Spinning Co., Ltd.). • Synthetic fiber b (in the table, "PP / PE1.7T"): A core-sheath composite fiber with a fineness of 1.7 dtex and a fiber length of 51 mm, consisting of a polypropylene core and a polyethylene sheath (product name: NBF(H)P, manufactured by Yamato Spinning Co., Ltd.). • Synthetic fiber c (in the table, "PET1.45T"): A single synthetic fiber made of polyethylene terephthalate with a fineness of 1.45 dtex and a fiber length of 38 mm (product name: Tetron, manufactured by Toray Industries, Inc.). • Synthetic fiber d (in the table, "PLA / PBS4.4T"): A core-sheath composite fiber with a fineness of 4.4 dtex and a fiber length of 51 mm, consisting of a core component of polylactic acid and a sheath component of polybutylene succinate (product name: Miracle Fiber KK-PL, manufactured by Yamato Spinning Co., Ltd.). • Synthetic fiber e (in the table, "Bio-PP / PE1.7T"): A core-sheath composite fiber with a fineness of 1.7 dtex and a fiber length of 51 mm, consisting of a core component made of bio-polypropylene resin (product name: HG475FB, Borealis) and a sheath component made of bio-polyethylene resin (product name: SE5311, LG).

[0114] Furthermore, the following nonwoven fabrics (fiber web B) were prepared to constitute the intermediate fiber layer in this embodiment. Wet-laid nonwoven fabric 1 (in the table, "pulp"): Made from 100% by mass of wood-derived pulp fibers (fineness approximately 1.0-4.0 dtex, fiber length approximately 0.8 mm-4.5 mm), with a basis weight of 17 g / m². 2 This is a wet-laid nonwoven fabric (manufactured by Habix Co., Ltd.) Wet-laid nonwoven fabric 2 (in the table, "pulp"): Made from 100% by mass of wood-derived pulp fibers (fineness approximately 1.0-4.0 dtex, fiber length approximately 0.8 mm-4.5 mm), with a basis weight of 26 g / m². 2 This is a wet-laid nonwoven fabric (manufactured by Habix). Heat-bonded nonwoven fabric (in the table, "Heat-bonded NW"): Made of synthetic fiber a, with a basis weight of 17 g / m². 2 A fiber web was fabricated using a parallel carding machine, and then subjected to a heat treatment for 5 seconds using a hot air penetration heat treatment machine set to 135°C, thereby bonding the fibers together with the sheath component of synthetic fiber a to obtain a heat-bonded nonwoven fabric. Scrim: Polypropylene filaments are arranged in a grid pattern, forming a square opening with sides of 8mm (the diagonal of the square is 11.3mm) with an opening ratio of 96%, and a basis weight of approximately 5.2g / m². 2 This is a mesh-like sheet (product name: Conwednet, manufactured by ENEOS Technomaterial Co., Ltd.)

[0115] (Example 1) A mixture of 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 was processed using a parallel carding machine to achieve a target yield of approximately 24 g / m². 2 Fiber webs A1 and A2 were then fabricated. A wet nonwoven fabric 1 was laminated as an intermediate fiber layer on a fiber web A1, and a fiber web A2 was laminated on the wet nonwoven fabric 1 to form a laminated fiber web. The laminated fiber web was placed on a 90-mesh plain weave support and transported at a speed of 4.0 m / min. A water flow entanglement treatment was performed by spraying a water stream at a water pressure of approximately 3 MPa once onto the surface of fiber web A2, followed by spraying a water stream at a water pressure of approximately 3 MPa once onto the surface of fiber web A1. The nozzle used for the water flow entanglement treatment had orifices with a hole diameter of 0.12 mm provided at 0.6 mm intervals, and the distance between the nozzle and the fiber web was 15 mm during the treatment.

[0116] Next, the fiber web after the water flow entanglement treatment was heated for 5 seconds using a hot air penetration type heat treatment machine set to 135°C to bond the fibers together with the sheath component of synthetic fiber a, and then subjected to a cooling process by natural cooling in an atmosphere of room temperature at 20°C to obtain the nonwoven fabric of Example 1.

[0117] (Examples 2-9, Comparative Examples 1-4) Except for the types and proportions of fibers constituting fiber webs A1 and A2, and the target areas of these fiber webs, as shown in Tables 1 to 3, nonwoven fabrics for Examples 2 to 9 and Comparative Examples 1 to 4 were obtained using the same procedure as in Example 1. However, for Example 7, hydrophilic cellulose fiber A has a basis weight of 17 g / m². 2 A card web was prepared and used as fiber web B (intermediate fiber layer after nonwoven fabric production). In Example 9 and Comparative Example 4, since synthetic fibers were not used, heat bonding treatment was not performed. Instead, drying treatment was carried out using a hot air penetration type heat treatment machine set to 100°C. In Comparative Example 3, heat bonding treatment was also not performed. Instead, drying treatment was carried out using a hot air penetration type heat treatment machine set to 100°C. For Example 6, Comparative Example 2, and Comparative Example 4, nonwoven fabrics were prepared without using fiber web B, resulting in single-layer nonwoven fabrics without an intermediate fiber layer.

[0118] (Examples 10-20) Except for the types and proportions of fibers constituting fiber webs A1 and A2, the targeting of these fiber webs, and fiber web B being as shown in Tables 4 and 5, nonwoven fabrics for Examples 10 to 20 were obtained using the same procedure as in Example 1. In Example 12, since synthetic fibers were not used in fiber layer A, heat bonding treatment was not performed. Instead, a drying treatment was carried out using a hot air penetration type heat treatment machine set to 100°C. Ta.

[0119] The evaluation of the nonwoven fabric was carried out as follows. <Thickness, thickness reduction rate, and bulk density of nonwoven fabric> A thickness measuring instrument (THICKNESS GAUGE Model CR-60A (product name) manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) was used to measure the thickness of the nonwoven fabric under loads of 0.3 kPa or 1.96 kPa. Furthermore, the decrease in thickness when a 1.96 kPa load was applied was calculated from the thickness when a 0.3 kPa load was applied as the thickness reduction rate. The bulk density was calculated from the thickness and basis weight when a load of 0.3 kPa was applied.

[0120] <Strength and elongation> The tensile strength was determined according to JIS L 1913:2010 6.3, using a constant-speed tension tensile testing machine. The sample width was 5 cm, the grip spacing was 10 cm, and the tensile speed was 30 ± 2 cm / min. The load value at break (tensile strength), elongation, and stress at 10% elongation (force required to elongate by 10%) were measured. The tensile tests were performed with the longitudinal (MD direction) and transverse (CD direction) of the nonwoven fabric as the tensile direction. The evaluation results are shown as the average of the values ​​measured for three samples. Tensile strength and other properties were measured in both dry (standard conditions, DRY) and wet (WET) conditions. For wet (WET) measurements, 250 parts by mass of distilled water were used to impregnate 100 parts by mass of the sample.

[0121] <Fuzz shedding measurement test> a) A disc (70mm in diameter, 350g) with its surface covered in urethane foam (manufactured by Inoac Corporation, product name Malt Filter MF-30, 5mm thick) is attached to the rotating shaft so that the axis of rotation is offset 20mm from the center of the disc. b) Lay down the same urethane foam as described above, and then fix the nonwoven fabric to the base so that one side of the nonwoven fabric is exposed. c) Place the disc on the nonwoven fabric. At this time, the only load applied to the nonwoven fabric is the weight of the disc itself. d) Rotate the axis of rotation to make the disc rotate on the nonwoven fabric. The rotation is performed in sets of 3 clockwise rotations and 3 counterclockwise rotations, for a total of 7 sets. The rotational speed at this time is approximately 3 seconds per rotation. e) After 7 sets of rotation, collect the fibers that have fallen off the nonwoven fabric and adhered to the surface of the urethane foam covering the disc. f) Perform the operations a) to e) above for n=3 nonwoven fabrics. Measure the mass of shed fibers for each of the three nonwoven fabrics, and define the average value as the amount of lint shedding.

[0122] <Dirt collection ability> [Dust collection ability] Seven types of test powders conforming to JIS Z 8901 were uniformly dispersed at a rate of 0.20 g each in a rectangular area measuring 5 cm x 15 cm (hereinafter referred to as the "dust dispersion area") approximately in the center of the surface of a white acrylic plate. The test powders (dust) were then wiped off using nonwoven fabric (29 cm x 21 cm) from the examples and comparative examples as a wiper.

[0123] The wiping was performed with a wiper jig (product name: Quickle Wiper [Tool Body] head, manufactured by Kao Corporation) attached to a nonwoven fabric so that the top surface (the surface where the water stream was sprayed during the partial entanglement process) was the wiping surface, with a load of 400 gf applied. The wiping was performed by moving the wiper back and forth once on the surface of the white acrylic plate.

[0124] More specifically, Position the wiper in the center of the dust dispersion area so that the vertical direction of the wiper aligns with the vertical direction of the dust dispersion area. From there, move the wiper 250mm towards the left edge of the dust dispersion area, rubbing it against the dust (white acrylic plate). Then, move the wiper 500mm toward the right edge of the dust dispersion area, Furthermore, move the wiper 250mm toward the left edge of the dust dispersion area. I spun the wiper back and forth once.

[0125] After wiping back and forth once with the wiper, the dust collection efficiency was determined from the mass of the nonwoven fabric measured beforehand and the mass of the nonwoven fabric measured after wiping. For each nonwoven fabric, the dust collection efficiency was measured three times with a fresh wiping surface, and the average value was taken as the dust collection efficiency.

[0126] [Hair capture ability (wet state)] Five strands of hair (approximately 5 cm long) were placed on the flooring, three horizontally and two vertically, spaced apart. The hair was then wiped off with the nonwoven fabrics used in the example and comparative example.

[0127] Wiping was performed in a wet state by impregnating 100 parts by mass of nonwoven fabric with 300 parts by mass of distilled water. The wiping was performed with the nonwoven fabric attached to a wiper jig (product name: Quickle Wiper [Tool Body] head, manufactured by Kao Corporation) so that the surface of fiber layer A was the wiping surface, with the area contributing to the wiping being 26 cm in the vertical direction and 16 cm in the horizontal direction, and a load of 400 gf was applied. Wiping was performed by moving the wiper back and forth once over the hair using the same method as used in the evaluation of dust collection performance above. After wiping, the collection rate (%) was calculated from the number of hairs wiped off the flooring. For each nonwoven fabric, wiping was measured three times with a fresh wiping surface of the nonwoven fabric, and the average value was taken as the hair collection rate.

[0128] [Sesame seed collecting ability (wet condition)] To evaluate sesame seed collection performance, 10 sesame seeds were placed on a flooring surface in three rows (3-4-3 rows) with spacing between them. The surface was wiped with a nonwoven fabric using the same method as for evaluating hair collection performance (in a wet state). After wiping, the collection rate (%) was calculated from the number of sesame seeds wiped off the flooring surface. For each nonwoven fabric, the wiping surface was replaced and measured three times, and the average value was taken as the sesame seed collection rate.

[0129] <Initial release amount, liquid residual rate> Initial release volume and liquid retention rate were determined by using a nonwoven fabric of the same size as the one used in the dirt collection test, and measuring the weight of the nonwoven fabric when dry (NW). d The weight of the nonwoven fabric is measured. 300 parts by mass of distilled water is impregnated into 100 parts by mass of nonwoven fabric, and the weight of the nonwoven fabric NW w The following measurements were taken. The nonwoven fabric was attached to a wiper jig (product name: Quickle Wiper [Tool Body] head, manufactured by Kao Corporation) so that the surface of fiber layer A was the wiping surface, with the area contributing to wiping being 26 cm in the vertical direction and 16 cm in the horizontal direction. With a load of 400 gf applied, the fabric was placed on the conveyor so that the direction of the conveyor's movement coincided with the horizontal direction (16 cm) of the nonwoven fabric, and the conveyor was operated at 5 m / min. The conveyor completed one rotation (0.5 tatami mats = 0.81 m). 2 ) Nonwoven fabric weight NW 0.5The initial release amount RA1 was determined from the following equation by measuring the value. RA1=NW w -NW 0.5

[0130] Next, the nonwoven fabric was similarly placed on the conveyor belt, and the weight of the nonwoven fabric (NW2, NW4, NW6, NW8) was measured after 2, 4, 6, and 8 rotations of the conveyor belt, and the liquid retention rate in the nonwoven fabric was determined. RR2 = 100 - ((NW w -NW2) / (NW w -NW d )×100) RR4 = 100 - ((NW w -NW4) / (NW w -NW d )×100) RR6 = 100 - ((NW w -NW6) / (NW w -NW d )×100) RR8 = 100 - ((NW w -NW8) / (NW w -NW d )×100)

[0131] The evaluation results for each example and comparative example are shown in Tables 1-5.

[0132] [Table 1]

[0133] [Table 2]

[0134] [Table 3]

[0135] [Table 4]

[0136] [Table 5]

[0137] All of the nonwoven fabrics in Examples 1-19 generally demonstrated excellent dirt-collecting properties (hair collection rate ≥30%, sesame seed collection rate >60%, and dust collection rate ≥34%) for at least two types of dirt, and showed particularly high sesame seed collection rates. In addition, all of the nonwoven fabrics in Examples 1-20 met the requirement of lint shedding of 10 mg or less, and some examples further met the requirement of initial release of 0.8 g or less.

[0138] In Example 2, among the examples containing the same water-repellent rayon as water-repellent cellulose fibers, the proportion of water-repellent cellulose fibers was the smallest and the proportion of hydrophilic cellulose fibers was the largest, resulting in a greater tendency for fiber entanglement. Therefore, among the examples containing water-repellent rayon, Example 2 tended to have slightly lower stain-collecting performance for all types of dirt compared to the other examples.

[0139] The results from Examples 1-4 showed that the higher the proportion of water-repellent cellulose fibers in fiber layer A, the higher the sesame seed collection rate and the better the collection of slightly larger dirt such as food scraps, but the amount of lint shedding tended to increase. This is thought to be because water-repellent cellulose fibers are less likely to become entangled by water flow, and also because they have low fiber strength and low rigidity.

[0140] Comparing Example 1 and Example 6, Example 6 showed higher dirt-collecting performance. This is thought to be because Example 6 does not contain an intermediate fiber layer, resulting in a lower degree of entanglement between fibers, a lower fiber density, and easier retention of dirt.

[0141] Examples 1 and 8 differ in the type of synthetic fiber contained in fiber layer A. Compared to Example 1, Example 8 showed superior dust collection performance. This is thought to be because the fineness of the synthetic fiber used in Example 8 was smaller than that of the synthetic fiber used in Example 1, forming finer interfiber voids, which in turn allowed for the collection of finer dirt particles, such as dust.

[0142] Examples 10 and 11 used water-repellent cotton and water-repellent lyocell, respectively, as water-repellent cellulose fibers. Compared to Example 1, Example 10 showed lower dust collection performance, but its collection performance for other types of dirt was superior to Comparative Examples 1 and 2. In addition, Example 10 had a larger initial release amount compared to Example 1. On the other hand, Example 10 had less lint shedding. From these findings, it is presumed that in Example 10, the water repellency of the water-repellent cotton was lower than that of the water-repellent rayon, the fibers were more intertwined, and the water-repellent cotton itself retained the liquid. As a result, in Example 10, the liquid contained in the water-repellent cotton increased the resistance during wiping, hindering the collection of dirt by the nonwoven fabric, resulting in slightly lower dirt collection performance. It is also thought that the stronger intertwining of the fibers resulted in less lint shedding. Example 11 showed higher hair capture performance compared to Example 1. This is presumed to be because, in Example 11, the entanglement of fibers by the water flow progressed more rapidly than in Example 1, making it easier for the columnar water flow to form groove-like ridges on the nonwoven fabric surface, and hair was captured along these grooves.

[0143] Example 12, in which the intermediate fiber layer was composed of a heat-bonded nonwoven fabric, showed dirt-collecting performance comparable to the other examples, but the initial release amount was larger. This is thought to be because the liquid was not well retained in the intermediate fiber layer made of synthetic fibers, and a large amount of liquid in the intermediate fiber layer was released initially. In addition, Example 12 showed a relatively high amount of lint shedding compared to the other examples. This is thought to be because fiber layer A did not contain synthetic fibers, and the fibers were not bonded to each other on the nonwoven fabric surface.

[0144] Example 13 uses a thin scrim for the intermediate fiber layer, and the basis weight of fiber layer A is increased compared to Example 1. Compared to Example 1, Example 13 showed higher hair capture performance. This is thought to be because the scrim was partially exposed on the fiber surface, making it easier for hair to get caught in the scrim portion. In addition, the initial release amount in Example 13 was larger. This is thought to be because the liquid is not easily retained by the thin scrim. The initial release amount in Example 13 is smaller than that of Example 12, which is thought to be because the basis weight of fiber layer A in Example 13 is larger, and the hydrophilic cellulose fibers contained therein retained the liquid to some extent.

[0145] Example 14 uses synthetic fibers that are thicker than those used in Example 1. Compared to Example 1, Example 14 showed higher hair and sesame seed capture performance. This is thought to be because the use of thicker synthetic fibers reduced the number of adhesion points formed by the synthetic fibers in fiber layer A, thereby increasing the degree of freedom of the fibers. Example 14 showed a larger initial release amount than Example 1. This is also thought to be due to the reduction in the number of adhesion points and the resulting increase in inter-fiber voids in fiber layer A.

[0146] Example 15 has a larger basis weight in the intermediate fiber layer and a larger basis weight in fiber layer A compared to Example 1. Compared to Example 1, Example 15 showed superior hair capture performance. This is thought to be because the larger amount of hydrophilic cellulose pulp facilitated entanglement of fibers by the water flow, making it easier for columnar water flow to form groove-like streaks on the nonwoven fabric surface, and hair was captured along these grooves. Furthermore, Example 15 showed a smaller initial release amount than Example 1. This is thought to be because the larger basis weight fiber layer allowed the liquid to be retained more easily. In addition, Example 15 showed a smaller amount of lint shedding than Example 1. This is thought to be because the basis weight of fiber layer A was smaller, resulting in a smaller amount of easily shed water-repellent cellulose fibers.

[0147] Example 16 uses hydrophilic cellulose fibers (rayon) with a finer fineness than those used in Example 1. When using fibers with a finer fineness, entanglement between fibers progresses, becoming stronger, and the inter-fiber voids in fiber layer A tend to decrease. Therefore, it is thought that the dirt-collecting ability is slightly lower and the amount of lint shedding is reduced compared to Example 1.

[0148] Examples 17 and 18 involved varying the fineness of the water-repellent cellulose fibers. A comparison of Examples 1, 17, and 18 showed that the greater the fineness of the water-repellent cellulose fibers, the higher the dirt-collecting ability and the greater the initial release amount tended to be. This is thought to be due to the formation of larger interfiber voids by using water-repellent cellulose fibers with a thicker fineness. The amount of lint shedding increased with increasing fineness, which is thought to be due to the reduction in fiber entanglement points by increasing the fineness.

[0149] Example 19 is an example using synthetic fibers made from polypropylene and polyethylene derived from biomass raw materials. Compared with Example 8, which used synthetic fibers made from polypropylene and polyethylene derived from petroleum raw materials, there was no significant change in performance. From these results, it was confirmed that synthetic fibers manufactured using resins derived from biomass raw materials can be applied to the nonwoven fabrics of this disclosure without any problems.

[0150] The nonwoven fabrics in Comparative Examples 1 and 2 both lacked water-repellent cellulose fibers and had a high proportion of hydrophilic cellulose fibers. Therefore, they were inferior in dirt-collecting ability compared to both examples.

[0151] The nonwoven fabric of Comparative Example 4 showed good dirt-collecting ability, but because the proportion of water-repellent cellulose fibers in the entire nonwoven fabric was large, it was prone to shedding lint and exhibited the largest amount of lint shedding. The nonwoven fabric of Comparative Example 4 also had a large initial release of liquid. This is thought to be because the proportion of water-repellent cellulose fibers was large and the fibers were not bonded to each other, resulting in excessively large interfiber voids, and the liquid accumulated in these voids was released all at once.

[0152] The nonwoven fabric of Comparative Example 3 is equivalent to that of Example 9, but with polyethylene terephthalate fibers instead of water-repellent cellulose fibers. The nonwoven fabric of Comparative Example 3 had lower dirt-collecting ability compared to that of Example 9. This is thought to be because the nonwoven fabric of Comparative Example 3 did not contain water-repellent cellulose fibers, making it less susceptible to deformation of the fibers due to wiping pressure. Furthermore, the nonwoven fabric of Comparative Example 3 had a larger initial release amount than that of Example 9. This is thought to be because the nonwoven fabric of Comparative Example 3 was thicker and bulkier, resulting in larger interfiber voids, which caused the liquid accumulated in these voids to be released all at once.

[0153] This embodiment includes the following aspects. (Aspect 1) A nonwoven fabric having a first surface and a second surface opposite to the first surface, Based on the total mass of the nonwoven fabric, it contains water-repellent cellulose fibers in a proportion of 10% to less than 75% by mass, and other fibers in a proportion of more than 25% to 90% by mass. At least one of the first surface and the second surface is the surface of a fiber layer A containing the water-repellent cellulose fibers in a proportion of 10% by mass or more and the other fibers in a proportion of 90% by mass or less. The fibers are integrated through entanglement. Nonwoven fabric for wipers. (Aspect 2) The nonwoven fabric comprises a first fiber layer, a second fiber layer, and an intermediate fiber layer located between the first fiber layer and the second fiber layer. The first surface is the surface of the first fiber layer, and 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 are fiber layer A. Nonwoven fabric for wipers according to embodiment 1. (Aspect 3) The nonwoven fabric for wipers according to embodiment 2, wherein the intermediate fiber layer contains hydrophilic cellulose fibers. (Aspect 4) The fiber layer A is a nonwoven fabric for wipers according to any of embodiments 1 to 3, wherein the other fibers include hydrophilic cellulose fibers. (Appendix 5) The nonwoven fabric for wipers according to embodiment 4, wherein the fiber layer A contains hydrophilic cellulose fibers in a proportion exceeding 0% by mass and not exceeding 75% by mass. (Aspect 6) The nonwoven fabric for wipers according to any of embodiments 1 to 5, wherein the fiber layer A comprises 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 as the other fibers. (Aspect 7) The nonwoven fabric for wipers according to embodiment 6, wherein the fiber layer A contains one or more types of synthetic fibers selected from synthetic fibers containing biomass raw materials and biodegradable synthetic fibers in a proportion exceeding 0% by mass and not exceeding 35% by mass. (Pattern 8) A method for manufacturing a nonwoven fabric having a first surface and a second surface opposite to the first surface, To prepare at least one fiber web A constituting at least one of the first surface and the second surface, the fiber web A contains 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 To produce a fiber web B other than the aforementioned fiber web A, and The fiber web A and the fiber web B are laminated to produce a laminated fiber web, and then subjected to a process to entangle the fibers. Includes, In preparing the fiber web A and the fiber web B, the types and proportions of the fibers constituting each fiber web, as well as the basis weight of each fiber web, are selected such that the laminated fiber web contains the water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and the other fibers in a proportion of more than 25% by mass and less than or equal to 90% by mass. A method for manufacturing nonwoven fabric for wipers. (Aspect 9) The fiber web B is placed between two identical or different fiber webs A, or between one fiber web A and a second fiber web B which is another fiber web, to create the laminated web, and the laminated web is subjected to a process to entangle the fibers. A method for manufacturing a nonwoven fabric for wipers according to embodiment 8. (Aspect 10) A method for manufacturing a nonwoven fabric having a first surface and a second surface opposite to the first surface, To prepare at least one fiber web A constituting at least one of the first surface and the second surface, the fiber web A contains water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and the other fibers in a proportion of more than 25% by mass and less than or equal to 90% by mass, and The single-layer or laminated web of the aforementioned fiber web A is subjected to a treatment that causes the fibers to intertwine. including, A method for manufacturing nonwoven fabric for wipers. (Aspect 11) One of the nonwoven fabrics for wipers according to any of embodiments 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 the wiping surface. Wiper. (Aspect 12) A wiper according to embodiment 11, which is a wiper for use against objects. [Industrial applicability]

[0154] The nonwoven fabric disclosed herein contains a predetermined proportion of water-repellent cellulose fibers, which have low rigidity and swell when wet with liquid, due to the liquid absorbed from the fiber cross-section, making them easily deformable by wiping pressure. Therefore, the nonwoven fabric disclosed herein is suitable for use as a wiper with excellent dirt-collecting properties, particularly as an object wiper for wiping off dirt of somewhat larger size.

Claims

1. A nonwoven fabric having a first surface and a second surface opposite the first surface, The nonwoven fabric contains water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and other fibers in a proportion of more than 25% by mass and 90% by mass or less, based on the total mass of the nonwoven fabric; At least one of the first surface and the second surface is a surface of a fiber layer A containing the water-repellent cellulose fiber in a proportion of 10% by mass or more and the other fiber in a proportion of 90% by mass or less, The fibers are intertwined and integrated. Nonwoven fabric for wipers.

2. the nonwoven fabric has a first fiber layer, a second fiber layer, and an intermediate fiber layer located between the first fiber layer and the second fiber layer; the first surface is a surface of the first fiber layer, and the second surface is a surface of the second fiber layer; 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 nonwoven fabric for wipers according to claim 2 , wherein the intermediate fibrous layer comprises hydrophilic cellulose fibers.

4. The nonwoven fabric for wipers according to any one of claims 1 to 3, wherein the fiber layer A contains hydrophilic cellulose fibers as the other fibers.

5. The nonwoven fabric for wipers according to claim 4 , wherein the fibrous layer A contains the hydrophilic cellulose fibers in a proportion of more than 0 mass % and not more than 75 mass %.

6. 4. The nonwoven fabric for wipers according to claim 1, wherein 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.

7. 7. The nonwoven fabric for wipers according to claim 6, wherein the fiber layer A contains one or more types of synthetic fibers selected from the group consisting of synthetic fibers containing biomass raw materials and biodegradable synthetic fibers in an amount of more than 0 mass% and not more than 35 mass%.

8. 1. A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising: As the fiber web A constituting at least one of the first surface and the second surface, at least one fiber 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 is prepared; and Producing a fiber web B other than the fiber web A; and The fiber web A and the fiber web B are laminated to prepare a laminated fiber web, and the laminated fiber web is subjected to a treatment for entangling the fibers. Including, When producing the fiber web A and the fiber web B, the types and proportions of fibers constituting each fiber web and the basis weight of each fiber web are selected so that the laminated fiber web contains the water-repellent cellulose fiber in a proportion of 10% by mass or more and less than 75% by mass, and the other fiber in a proportion of more than 25% by mass and 90% by mass or less. Manufacturing method of nonwoven fabric for wipers.

9. The fiber web B is disposed between two of the same or different fiber webs A, or between one fiber web A and a second fiber web B, which is another fiber web, to prepare the laminated web, and the laminated web is subjected to a treatment for entangling the fibers. The method for producing the nonwoven fabric for wipers according to claim 8.

10. 1. A method for producing a nonwoven fabric having a first surface and a second surface opposite the first surface, comprising: As a fiber web A constituting at least one of the first surface and the second surface, at least one fiber web is prepared, the fiber web containing water-repellent cellulose fibers in a proportion of 10% by mass or more and less than 75% by mass, and the other fibers in a proportion of more than 25% by mass and 90% by mass or less; and The single layer or laminated web of the fiber web A is subjected to a treatment for entangling the fibers. Including, Manufacturing method of nonwoven fabric for wipers.

11. The nonwoven fabric for wipers 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 1,000 parts by mass or less relative to 100 parts by mass of the nonwoven fabric for wipers, 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.