Laminated nonwoven fabric and manufacturing method thereof and liquid impregnated sheet

Abstract

To provide a laminated nonwoven fabric that has smooth surface hardly causing sense of friction when being used in contact with skin or object, and has relatively high mechanical strength in a wet state.SOLUTION: A laminated nonwoven fabric comprises: 1A and 1B fiber layers including 70 to 100 mass% of 1a and 1b cellulosic fibers having strength in normal state of 2.8 cN / dtex or less and / or strength in wet state of 2.0 cN / dtex or less, and average fiber diameter of 0.1 μm or more and 12.0 μm or less; and a second fiber layer that is located between the two fiber layers and includes 40 to 100 mass% of a second cellulosic fiber having strength in normal state of 2.4 cN / dtex or more and / or strength in wet state of 1.9 cN / dtex or more, and average fiber diameter of 7.0 μm or more and 25 μm or less. The average fiber diameters and strength in normal state and strength in wet state of the 1a and 1b cellulosic fibers are larger than those of the second cellulosic fiber. Three fiber layers are integrated by entanglement of fibers.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a nonwoven fabric, a method for producing the same, and a liquid-impregnated sheet using the same. [Background technology]

[0002] Various liquid-impregnated sheets ("liquid-impregnated sheets") made of nonwoven fabric, paper, or the like have been proposed and put into practical use for use, for example, to remove or apply a predetermined substance to human skin, or to wipe away dirt from objects. Liquid-impregnated sheets are often provided as sheets containing hydrophilic fibers so that they can be impregnated with a predetermined amount of liquid depending on the application, and cellulosic fibers such as cotton and rayon are often used as the hydrophilic fibers.

[0003] For example, Patent Document 1 proposes a cosmetic sheet comprising a multilayer nonwoven fabric having multiple nonwoven fabric layers, the multilayer nonwoven fabric having one or more first layers being nonwoven fabric with a fiber diameter of 0.1 to 8 μm and containing 50% or more by mass of cellulosic fibers, and one or more second layers being nonwoven fabric with a fiber diameter of 10 to 20 μm and containing 50% or more by mass of cellulosic fibers, the second layer being present on at least one surface of the multilayer nonwoven fabric, and the multilayer nonwoven fabric having a water absorption rate of 75 mm or more based on the Byreck test in accordance with JIS-L1907. Patent Document 2 proposes a two- or three-layer nonwoven fabric in which the surface layer contains 60% by mass or more of fiber I having a fiber diameter of 0.1 μm or more and 6.0 μm or less, and the back layer in the two-layer case and the middle layer in the three-layer case contain 50% by mass or more of fiber II having a fiber diameter of 8.0 μm or more and 30.0 μm or less, and 80% by mass or more and 100% by mass or less of the fibers contained in the nonwoven fabric are fibers with a substantially circular cross-sectional shape. Patent Document 2 further proposes that 80% by mass or more and 100% by mass or less of the fibers contained in the nonwoven fabric be cellulosic fibers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-226179 [Patent Document 2] Japanese Patent Publication No. 2022-61310 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a laminated nonwoven fabric containing cellulosic fibers, which has a smooth surface that is less likely to cause friction when placed against the skin or an object, and which has relatively high mechanical strength in a wet state. [Means for solving the problem]

[0006] The nonwoven fabric of the present disclosure comprises a first A fiber layer, a first B fiber layer, and a second fiber layer located between the first A fiber layer and the first B fiber layer, the 1A fiber layer has a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and contains 1a cellulosic fibers having an average fiber diameter of 0.1 μm or more and 12.0 μm or less in a proportion of 70% by mass or more and 100% by mass or less; the 1B fiber layer has a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and contains 1b cellulosic fibers having an average fiber diameter of 0.1 μm or more and 12.0 μm or less in a proportion of 70% by mass or more and 100% by mass or less, the second fiber layer contains second cellulosic fibers in a proportion of 40% by mass or more and 100% by mass or less, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more and an average fiber diameter of 7.0 μm or more and 25 μm or less, the average fiber diameter of the 1a cellulosic fibers and the 1b cellulosic fibers is smaller than the average fiber diameter of the second cellulosic fibers; the standard strength and wet strength of the 1a cellulosic fiber and the 1b cellulosic fiber are smaller than the standard strength and wet strength of the second cellulosic fiber; The first A fiber layer, the second fiber layer, and the first B fiber layer are integrated by entanglement of the fibers, forming a laminated nonwoven fabric. [Effects of the Invention]

[0007] The laminated nonwoven fabric of the present disclosure contains cellulosic fibers with smaller fiber diameters in the first A and first B fiber layers located on the front and back surfaces of the nonwoven fabric, and the second fiber layer, which serves as an intermediate fiber layer located between these fiber layers, contains specific cellulosic fibers. This allows the fabric to have smooth surfaces on both sides that are less likely to feel friction when placed against the skin or an object, and also exhibits relatively high mechanical strength even in a wet state. Therefore, the laminated nonwoven fabric of the present disclosure can reduce the burden on the object (person or object) against which it is placed, is easy to handle even when impregnated with liquid, and is suitable for a variety of uses. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an electron microscope photograph of a cross section of the nonwoven fabric obtained in Example 1, magnified 100 times. [Figure 2] 1 is an electron microscope photograph of a cross section of the nonwoven fabric obtained in Comparative Example 1, magnified 100 times. [Figure 3] 1 is an electron microscope photograph of a cross section of the nonwoven fabric obtained in Comparative Example 2, magnified 100 times. [Figure 4] FIG. 1 is an electron microscope photograph in which dashed lines are added to indicate the bends and twists observed in the second cellulosic fiber. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Background to the present embodiment) Both Patent Documents 1 and 2 use two types of fibers with different fiber diameters, with the smaller fiber diameter present in greater amounts on the outer surface, thereby reducing skin irritation and improving surface smoothness. However, the inventors have found that when nonwoven fabrics using cellulose-based fibers with fibers that differ only in fiber diameter, the nonwoven fabric tends to stretch when wet, resulting in poor handleability and usability, or the nonwoven fabric may become twisted or exhibit significant misalignment between the layers constituting the nonwoven fabric. Further investigation has revealed that when using cellulose-based fibers, selecting the cellulose-based fibers contained in each layer of a laminated nonwoven fabric based on not only the fiber diameter but also the dry strength and / or wet strength can improve mechanical strength and surface smoothness. Furthermore, the inventors have found that the fine bends and / or twists of fibers with larger fiber diameters are related to surface smoothness. Based on these findings, the laminated nonwoven fabric of this embodiment will be described below.

[0010] The nonwoven fabric of this embodiment includes specific 1a cellulosic fibers, specific 1b cellulosic fibers, and specific second cellulosic fibers, which will be described below.

[0011] (1a / 1b cellulosic fibers) Both the 1a cellulose fiber and the 1b cellulose fiber are cellulose fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less, and an average fiber diameter of 0.1 μm or more and 12 μm or less.

[0012] In this specification, the 1a cellulosic fibers are specified as those contained in the 1A fiber layer constituting one surface of the laminated nonwoven fabric, and the 1b cellulosic fibers are specified as those contained in the 1B fiber layer constituting the other surface of the laminated nonwoven fabric. The 1a cellulosic fibers and the 1b cellulosic fibers are specified separately to clarify that the 1a cellulosic fibers and the 1b cellulosic fibers are independent of each other and may be the same or different. However, because the 1a cellulosic fibers and the 1b cellulosic fibers must satisfy the same conditions, they are sometimes collectively referred to as the "first cellulosic fibers" in this specification. Furthermore, as described below, in this specification, when the 1A fiber layer and the 1B fiber layer are described in common, they are sometimes collectively referred to as the "first fiber layer."

[0013] Examples of cellulosic fibers include: (1) Natural fibers derived from plants such as cotton, flax, flax, ramie, jute, banana, bamboo, kenaf, shell ginger, hemp, and kapok; (2) Rayon and Polynosic obtained by the viscose process, cupra obtained by the cuprammonium process, and Lyocell (e.g., Tencel®), a solvent-spun cellulose fiber, as well as other regenerated fibers; (3) cellulose fibers obtained by melt spinning; and (4) Semi-synthetic fibers such as acetate fibers Examples include:

[0014] Among these, fibers suitable for use as the first cellulose fiber, i.e., fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less, include rayon, cupra, acetate, and the like obtained by the viscose process, and preferably regenerated cellulose such as rayon or cupra. Rayon is particularly preferred because its average fiber diameter can be easily adjusted, it has been used as a fiber for liquid-impregnated sheets, and it provides flexibility to nonwoven fabrics. The first cellulose fiber is preferably hydrophilic. When the nonwoven fabric of this embodiment is used as a liquid-impregnated sheet, the hydrophilicity of the first cellulose fiber facilitates the liquid impregnation process and facilitates retention of the impregnated liquid. Furthermore, when the nonwoven fabric of this embodiment is produced by entangling fibers using a high-pressure fluid flow, particularly a high-pressure water flow, the hydrophilicity of the first cellulose fiber facilitates entanglement, thereby improving the mechanical strength of the nonwoven fabric.

[0015] The reason for using the first cellulosic fibers having the above-mentioned specific standard strength and / or wet strength and fiber diameter is to make the first fiber layer containing the first cellulosic fibers soft to the touch and to make its surface dense and smooth. If the standard strength exceeds 2.8 cN / dtex and the wet strength exceeds 2.0 cN / dtex, the surface of the first fiber layer may feel hard to the touch, and the nonwoven fabric itself may have poor bendability, which may reduce its ability to conform to an object (e.g., a person's face) when placed against it. The standard strength of the first cellulosic fibers may be particularly 0.5 cN / dtex to 2.8 cN / dtex, more particularly 0.7 cN / dtex to 2.5 cN / dtex, and the wet strength may be particularly 0.5 cN / dtex to 2.0 cN / dtex, more particularly 0.7 cN / dtex to 1.8 cN / dtex. The standard strength of cellulosic fibers is measured in accordance with JIS L 1015 8.7 (tensile strength and elongation) 8.7.1 (standard test):2010, and the wet strength described below is measured in accordance with JIS L 1015 8.7.2 (wet test).

[0016] The average fiber diameter is measured using the following procedure. First, a sample of a nonwoven fabric or a sample of a nonwoven fabric loosened into a flocculent form is fixed and cut at a desired location to obtain an observation surface on which the cross sections of the cellulosic fibers can be observed, and this is then observed under an electron microscope. The observation field is set so that the cross sections of 50 or more cellulosic fibers can be observed. The magnification is, for example, 500x. 50 cellulosic fibers are randomly selected from the observation field, and their major diameter (the longest line segment connecting any two points on the periphery of the fiber cross section) and minor diameter (the longest line segment connecting two points on the periphery and perpendicular to the major diameter) are calculated using analysis software. The average of the calculated major and minor diameters is taken as the average fiber diameter of the cellulosic fibers.

[0017] The average fiber diameter of the first cellulose fiber may be 0.1 μm or more and 12 μm or less, particularly 0.1 μm or more and 10 μm or less, more particularly 0.5 μm or more and 9.5 μm or less, and even more particularly 1.0 μm or more and 9.0 μm or less. If the average fiber diameter of the first cellulose fiber is less than 0.1 μm, the strength of the fiber itself may be low, resulting in a nonwoven fabric with too little mechanical strength when wet. Furthermore, when a nonwoven fabric is produced by entangling fibers with a high-pressure fluid flow, the nonwoven fabric may become too dense, resulting in a poor tactile feel. Furthermore, when the nonwoven fabric is used for wiping, it becomes difficult to capture oils (especially human skin sebum) and dirt from the object into the nonwoven fabric. Furthermore, a nonwoven fabric surface that is too dense is prone to clogging due to dirt, etc., and as a result, when the nonwoven fabric is used for wiping, its oil and dirt removal effect may be quickly reduced. Furthermore, if the first fiber layer is too dense, it may affect the entanglement with the second cellulosic fibers of the second fiber layer, making it difficult to build and maintain a laminated structure. If the average fiber diameter of the first cellulosic fibers exceeds 12 μm, the surface smoothness of the first fiber layer may decrease, resulting in a poor tactile feel. Furthermore, when the nonwoven fabric is used for wiping, the surface of the nonwoven fabric may become too loose, causing oil and dirt that have been absorbed into the nonwoven fabric to fall off during the wiping operation, resulting in the oil and dirt re-adhering to the object.

[0018] The fiber length of the first cellulosic fibers is appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. For example, when the nonwoven fabric is manufactured by preparing a carded web, the fiber length may be 20 mm or more and 100 mm or less, particularly 28 mm or more and 75 mm or less, and more particularly 30 mm or more and 65 mm or less. When the nonwoven fabric is manufactured by preparing an airlaid web, the fiber length may be 1 mm or more and 50 mm or less, particularly 2 mm or more and 20 mm or less. Alternatively, when the first fiber layer is in the form of a long-fiber nonwoven fabric, the first cellulosic fibers may be long fibers.

[0019] As mentioned above, the 1a cellulosic fibers and the 1b cellulosic fibers may be different from each other or may be the same. For example, the 1a cellulosic fibers and the 1b cellulosic fibers may differ in fineness and / or type. Alternatively, one may be a long fiber and the other a short fiber with a fiber length of 100 mm or less.

[0020] The 1A fibrous layer may include multiple types of cellulosic fibers as the 1a cellulosic fibers, and similarly, the 1B fibrous layer may include multiple types of cellulosic fibers as the 1b cellulosic fibers.

[0021] When the 1A fiber layer contains two or more types of 1a cellulosic fibers, it may be difficult to determine the average fiber diameter for each type. In this case, the average fiber diameter of the 1a cellulosic fibers is determined as the average fiber diameter of all cellulosic fibers whose standard strength and / or wet strength are within the above-mentioned specified range, regardless of the type. The same applies when the 1B cellulosic fibers contain two or more types of 1b cellulosic fibers.

[0022] (Second cellulosic fiber) The second cellulose fiber has a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more, and an average fiber diameter of 7.0 μm to 25 μm. Among the cellulose fibers exemplified above, those having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more are regenerated cellulose fibers such as polynosic obtained by the viscose process, high wet modulus rayon, and solvent-spun cellulose fibers such as lyocell. Lyocell is particularly preferred because it tends to have bent or twisted portions, as described below, and thus easily improves the surface smoothness of nonwoven fabrics. The second cellulose fiber is preferably hydrophilic. The reason for this is as explained above in connection with the first cellulose fiber.

[0023] A portion of the second cellulose fibers may be those in which seven or more second cellulose fibers having bends and / or twists are observed in the second fiber layer in a 1280 μm × 960 μm region of an electron microscope photograph of a cross section of a nonwoven fabric configured as described below at 100x magnification. The bends or twists referred to here are distinct from curves formed by bending fibers during the production of the nonwoven fabric, and are observed as uneven fiber sides caused by multiple small bends or twists. An example of a cellulose fiber having bends and / or twists is shown in FIGS. 1 and 4 (FIG. 4 corresponds to the bends and twists in FIG. 1 surrounded by dashed lines). More specifically, the bends and / or twists refer to areas where the surface of the fiber is pinched or twisted, or where the surface of the fiber has creases or cracks, as in the area surrounded by dashed lines in FIG. 4.

[0024] When the second cellulosic fibers have bent and / or twisted portions, it is believed that the first cellulosic fibers are more likely to become entangled in the bent and / or twisted portions, facilitating fixation to the second cellulosic fibers, which in turn reduces twisting and shifting of the first fiber layer containing the first cellulosic fibers and helps maintain the smoothness of the surface of the first fiber layer.

[0025] The presence or absence of bends and / or twists in the second cellulose fibers in the second fiber layer of the nonwoven fabric is observed using the following procedure. First, the cross section of the nonwoven fabric is observed using a scanning electron microscope (SEM, accelerating voltage: 5.00 kV, magnification: 100x). In the SEM image, if bends and / or twists are present on the fiber surface of second cellulose fibers with an average fiber diameter of 7.0 μm or more and 25 μm or less in the layer corresponding to the second fiber layer, the second cellulose fibers are counted as one fiber having a bend and / or twist. This observation is repeated for three different SEM images, and the average number of second cellulose fibers having bends and / or twists is calculated. This average value represents the number of second cellulose fibers having bends and / or twists in the second fiber layer of the nonwoven fabric. The fiber web before production of the nonwoven fabric is also observed using the same procedure.

[0026] The bends and / or twists in the second cellulose fiber can be observed even in the fiber stage before being made into a nonwoven fabric. Meanwhile, their frequency of occurrence tends to increase as the fiber undergoes the carding process and / or hydroentanglement process during nonwoven fabric production. This is thought to be due to the appearance of new bends, particularly spiral-shaped bends, during these processes. Because the second cellulose fiber has a standard strength of 2.4 N / dtex or more and / or a wet strength of 1.9 cN / dtex or more, when subjected to a physical action, the fiber is likely to retain a history of the shape change caused by the physical action, resulting in a greater degree of shape change before and after the physical action. These bends and / or twists tend to occur more when the second cellulose fiber has a standard strength of 2.4 cN / dtex or more, particularly 2.8 cN / dtex or more, more particularly 3.0 cN / dtex or more, or when the wet strength is 1.9 cN / dtex or more, particularly 2.0 cN / dtex or more, more particularly 2.2 cN / dtex or more.

[0027] The reason for using the second cellulosic fibers having the above-mentioned specific standard strength and / or wet strength and fiber diameter is to improve the mechanical strength of the nonwoven fabric and to make the surface of the first fiber layer smoother. If the standard strength of the second cellulosic fibers is less than 2.4 cN / dtex and the wet strength is less than 1.9 cN / dtex, the mechanical strength of the nonwoven fabric may be insufficient depending on the application, and the first fiber layer may be prone to twisting and shifting during use, resulting in a decrease in the surface smoothness of the first fiber layer. The second cellulosic fiber may have a standard tenacity of 2.4 to 5.0 cN / dtex, more particularly 2.4 to 4.0 cN / dtex, even more particularly 2.6 to 3.8 cN / dtex, and a wet tenacity of 1.9 to 4.0 cN / dtex, more particularly 2.0 to 3.6 cN / dtex, even more particularly 2.1 to 3.4 cN / dtex. The second cellulosic fiber may also have a standard tenacity of 3.0 dtex or greater and / or a wet tenacity of 2.2 cN / dtex or greater.

[0028] By having the average fiber diameter of the second cellulose fiber be 7 μm or more and 25 μm or less, in combination with the standard strength and / or wet strength of the second cellulose fiber being within the above range, it is possible to relatively increase the mechanical strength of the nonwoven fabric, particularly the wet mechanical strength. If the average fiber diameter of the second cellulose fiber is less than 7 μm, the strength of the fiber itself may be low, resulting in too low wet mechanical strength of the nonwoven fabric. Furthermore, the entanglement with the first cellulose fiber of the first fiber layer may be reduced, making it difficult to establish and maintain a laminated structure. Furthermore, if the average fiber diameter of the second cellulose fiber is less than 7 μm, the first fiber layer may be prone to twisting and slippage. If the average fiber diameter exceeds 25 μm, the second fiber layer may become stiff, reducing the flexibility of the entire nonwoven fabric. Furthermore, if the second cellulose fiber of the second fiber layer is exposed to the first fiber layer, the tactile feel of the first fiber layer may be reduced. The average fiber diameter of the second cellulosic fibers may particularly be 10 μm or more and 25 μm or less, more particularly 10.5 μm or more and 24.5 μm or less, and even more particularly 11.0 μm or more and 24.0 μm or less.

[0029] The fiber length of the second cellulosic fibers is appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. For example, when a carded web is produced to manufacture the nonwoven fabric, the fiber length may be 20 mm or more and 100 mm or less, particularly 28 mm or more and 75 mm or less, and more particularly 30 mm or more and 65 mm or less. When an air-laid web is produced to manufacture the nonwoven fabric, the fiber length may be 1 mm or more and 50 mm or less, particularly 2 mm or more and 20 mm or less. Alternatively, when the second fiber layer is in the form of a long-fiber nonwoven fabric, the second cellulosic fibers may be long fibers.

[0030] The second fibrous layer may contain multiple types of cellulosic fibers as the second cellulose fibers. In this case, the average fiber diameter of the second cellulose fibers is the average fiber diameter of all the cellulosic fibers having standard strength and / or wet strength within the above ranges, as described in relation to the first fibrous layer.

[0031] (Other fibers) As described below, the first fibrous layer and the second fibrous layer may each contain fibers other than the first cellulosic fibers and the second cellulosic fibers (hereinafter referred to as "other fibers").

[0032] The other fibers may be, for example, synthetic fibers made of a thermoplastic resin. The thermoplastic resin constituting the synthetic fibers is not particularly limited, and examples include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof; polyolefin-based resins such as polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene copolymers containing propylene as the main component (including propylene-ethylene copolymer and propylene-butene-1-ethylene copolymer), ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer; polyamide-based resins such as nylon 6, nylon 12, and nylon 66; acrylic resins; engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefins, as well as elastomers thereof. Synthetic fibers may be produced using one or more thermoplastic resins arbitrarily selected from these.

[0033] The synthetic fiber may be a single fiber made of one or more thermoplastic resins selected from the above, or may be a bicomponent fiber made of two or more components (also called "sections"). In the bicomponent fiber, each component may be made of a single thermoplastic resin, or may be a mixture of two or more thermoplastic resins. The bicomponent fiber may be, for example, a sheath-core bicomponent fiber, an islands-in-the-sea bicomponent fiber, or a side-by-side bicomponent fiber. The sheath-core bicomponent fiber may be an eccentric sheath-core bicomponent fiber in which the center of the core component and the center of the sheath component do not coincide in the fiber cross section, or a concentric sheath-core bicomponent fiber in which the center of the core component and the center of the sheath component coincide in the fiber cross section. The bicomponent fiber may also be a splittable bicomponent fiber.

[0034] When the first fiber layer contains synthetic fibers as other fibers, the fiber diameter of the synthetic fibers may be within the range of the average fiber diameter that the first cellulosic fibers should satisfy. In this case, the fiber diameters of the fibers contained in the first fiber layer are relatively uniform, making the surface of the first fiber layer more uniform and less likely to be impaired by the inclusion of the first cellulosic fibers. Similarly, when the second fiber layer contains synthetic fibers as other fibers, the fiber diameter of the synthetic fibers may be within the range of the average fiber diameter that the second cellulosic fibers should satisfy.

[0035] Alternatively, the other fibers contained in the first fiber layer may be a cellulosic fiber other than the first cellulosic fiber (for convenience, this will be referred to as "cellulosic fiber A"). For example, cellulosic fiber A may be a second cellulosic fiber, or may be rayon, cotton, or the like, whose standard strength, wet strength, and / or average fiber diameter are outside the ranges required for the first cellulosic fiber. Cellulosic fiber A may also be water-repellent. By making cellulosic fiber A water-repellent, when the first fiber layer is used to wipe an object (especially human skin) in a wet state, the amount of liquid in the first fiber layer can be reduced, reducing wiping resistance and enabling wiping with lighter movements. Furthermore, by adjusting the proportion of water-repellent fibers so that the water-repellency of the first fiber layer is higher than that of the second fiber layer, the liquid retained in the second fiber layer can gradually move to the first fiber layer and be released onto the object, allowing wiping to be performed for a longer period of time or over a wider area.

[0036] Similarly, the other fibers contained in the second fiber layer may be cellulosic fibers other than the second cellulosic fiber (for convenience, these will be referred to as "cellulosic fiber B"). For example, cellulosic fiber B may be the first cellulosic fiber, or may be lyocell, cotton, or the like, whose standard strength, wet strength, and / or average fiber diameter are outside the ranges that the second cellulosic fiber must satisfy. Cellulosic fiber B may also be water-repellent. By making cellulosic fiber B water-repellent, the proportion of cellulosic fiber B can be adjusted to control the entanglement state of the first fiber layer and the second fiber layer, making it possible to obtain a touch and texture appropriate for the intended use.

[0037] If the first fiber layer, first fiber layer, and second fiber layer contain other fibers, and if all of the other fibers are cellulosic fibers, the nonwoven fabric can be made into an "all-cellulose" structure. All-cellulose nonwoven fabrics are biodegradable and can be marketed as environmentally friendly products.

[0038] Alternatively, the other fibers contained in the 1A fiber layer, the 1B fiber layer and the second fiber layer may be protein-based fibers such as silk and wool.

[0039] The fiber length of the other fibers is appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. For example, when a carded web is produced to manufacture the nonwoven fabric, the fiber length may be 20 mm or more and 100 mm or less, particularly 28 mm or more and 75 mm or less, and more particularly 30 mm or more and 65 mm or less. When an air-laid web is produced to manufacture the nonwoven fabric, the fiber length may be 1 mm or more and 50 mm or less, particularly 2 mm or more and 20 mm or less. Alternatively, when one or more of the first A fiber layer, the first B fiber layer, and the second fiber layer are in the form of a long-fiber nonwoven fabric, the other fibers contained in the layer may be long fibers.

[0040] (Nonwoven fabric composition) The nonwoven fabric of this embodiment is a laminated nonwoven fabric comprising a 1A fiber layer, a 1B fiber layer, and a second fiber layer located between the 1A and 1B fiber layers, the 1A fiber layer and the 1B fiber layer containing the first cellulosic fibers, identified as 1a cellulosic fibers and 1b cellulosic fibers, in an amount of 70% to 100% by mass, respectively, and the second fiber layer containing the second cellulosic fibers in an amount of 40% to 100% by mass. In this laminated nonwoven fabric, the 1A fiber layer and the 1B fiber layer constitute both sides of the nonwoven fabric, respectively, and the second fiber layer is an intermediate layer located between the two layers.

[0041] The 1A fiber layer and the 1B fiber layer are independent of each other and may be the same or different. Since the 1A fiber layer and the 1B fiber layer must satisfy the same conditions, in the description common to both the 1A fiber layer and the 1B fiber layer, these fiber layers may be collectively referred to as the "first fiber layer."

[0042] The first cellulose fibers contained in the first fiber layer and the second cellulose fibers contained in the second fiber layer are as described above. When forming the first and second fiber layers, the first cellulose fibers and the second cellulose fibers are selected so that the average fiber diameter of the first cellulose fibers is smaller than the average fiber diameter of the second cellulose fibers. When the 1a cellulose fibers and the 1b cellulose fibers have different fiber diameters, the 1a and 1b cellulose fibers and the second cellulose fibers are selected so that the average fiber diameter of each is smaller than the average fiber diameter of the second cellulose fibers. For example, the ratio of the average fiber diameter of the first cellulose fibers to the average fiber diameter of the second cellulose fibers may be greater than 1 and less than 1.75. A ratio of average fiber diameters within this range tends to result in a smaller MMD, as described below. This is thought to be because a smaller average fiber diameter ratio reduces voids in the nonwoven fabric, resulting in a smoother surface.

[0043] In forming the first and second fibrous layers, the first and second cellulosic fibers are selected so that the standard strength and wet strength of the first cellulosic fiber are lower than the standard strength and wet strength of the second cellulosic fiber, respectively. In particular, the first and second cellulosic fibers may be selected so that the standard strength of the first cellulosic fiber is at least 0.4 cN / dtex lower than the standard strength of the second cellulosic fiber, or the wet strength of the first cellulosic fiber is at least 0.4 cN / dtex lower than the wet strength of the second cellulosic fiber. The difference (absolute value) in the standard strength between the first and second cellulosic fibers may be at least 0.4 cN / dtex and at most 1.5 cN / dtex, more particularly at least 0.5 cN / dtex and at most 1.4 cN / dtex. If the difference in strength between the first cellulosic fiber and the second cellulosic fiber is small, the effects of using two types of cellulosic fiber (such as improved smoothness and / or mechanical strength) may be reduced.

[0044] The first fiber layer contains 70% by mass or more of first cellulosic fibers having a lower standard strength and / or wet strength and a smaller fiber diameter, which makes the surface of the first fiber layer denser and smoother, and thus provides a smooth wiping surface suitable for use against human skin or for wiping dirt off objects.

[0045] If the proportion of the first cellulosic fiber in the first fiber layer is less than 70% by mass, the surface density and smoothness of the first fiber layer may decrease. If the proportion of the first cellulosic fiber in the first fiber layer is 100% by mass (i.e., if the first fiber layer is composed only of the first cellulosic fiber), not only will the surface density and smoothness of the first fiber layer be good, but the uniformity will also be improved by being composed of the same type of fiber, cellulose.

[0046] The second fiber layer contains 40% by mass or more of second cellulose fibers having a larger fiber diameter and a higher standard strength and / or wet strength, and serves to improve the mechanical strength of the laminated nonwoven fabric, particularly the mechanical strength when wet, and more particularly the stress at 10% elongation in the CD direction (cross direction) when wet.

[0047] In the second fiber layer, seven or more second cellulose fibers having bent portions and / or twisted portions may be observed in an area of ​​1280 μm × 960 μm in an electron microscope photograph of the cross section of the nonwoven fabric magnified 100 times. As described above, the second cellulose fibers having bent portions or twisted portions further improve the smoothness of the surface of the first fiber layer. The reason why the second cellulose fibers having bent portions or twisted portions improve the smoothness of the nonwoven fabric surface is thought to be that the first cellulose fibers are easily fixed by the bent portions or twisted portions, as described above.

[0048] In this embodiment, the basis weight of the 1A fiber layer and the 1B fiber layer is, for example, 5 g / m 2 More than 40g / m 2 or less, in particular 6 g / m 2 More than 35g / m 2 Below, more particularly 7 g / m 2 More than 28g / m 2 or less. If the basis weight of the 1A fiber layer and the 1B fiber layer is too small, the thickness of the 1A fiber layer and the 1B fiber layer will be small, and the second cellulosic fibers contained in the second fiber layer will be more likely to appear on the surface of the 1A fiber layer and the 1B fiber layer, which may impair smoothness. If the basis weight of the 1A fiber layer and the 1B fiber layer is too large, entanglement between the 1A fiber layer and the 1B fiber layer and the second fiber layer will be insufficient, which may cause fluffing and shedding of the 1a cellulosic fibers and 1b cellulosic fibers, which have smaller fiber diameters.

[0049] The basis weight of the second fiber layer is, for example, 10 g / m 2 More than 40g / m 2 or less, in particular 15 g / m 2 More than 37g / m2 Below, more particularly 18 g / m 2 More than 35g / m 2 If the basis weight of the second fiber layer is too small, the mechanical strength of the nonwoven fabric may be insufficient. If the basis weight of the second fiber layer is too large, the feel of the nonwoven fabric may be dominated by the second fiber layer, resulting in a stiff texture.

[0050] The ratio of the basis weight of each of the 1A fiber layer and the 1B fiber layer to the basis weight of the second fiber layer may be, for example, 1:9 (1A (1B):2) to 9:1, particularly 2:8 to 8:2, and more particularly 3:7 to 7:3. The ratio of the sum of the basis weight of the 1A fiber layer and the basis weight of the 1B fiber layer to the basis weight of the second fiber layer may be, for example, 1:9 ([1A + 1B]:2) to 9:1, particularly 2:8 to 8:2, and more particularly 3:7 to 7:3.

[0051] In the nonwoven fabric of this embodiment, the 1A fiber layer and the 1B fiber layer may be identical and have the same basis weight and fiber structure, or may differ in one or more of basis weight, fiber structure (including fiber ratio and type), fiber layer preparation method, etc. For example, if the fiber diameter of the 1a cellulosic fibers in the 1A fiber layer is smaller than that of the 1b cellulosic fibers in the 1B fiber layer, a laminated nonwoven fabric can be obtained that is smooth on both sides but has slightly different textures on the front and back sides due to the difference in fiber diameter.

[0052] In the nonwoven fabric of this embodiment, the fibers within and between the 1A fiber layer, 1B fiber layer, and 2nd fiber layer are integrated by entanglement. The entanglement of the fibers may be achieved, for example, by needle punching or high-pressure fluid flow (particularly water flow) entanglement. In this embodiment, it is preferable that the fibers are integrated by high-pressure fluid flow (particularly water flow) entanglement. The entanglement using high-pressure fluid flow can make the surface of the nonwoven fabric smoother. Furthermore, when the high-pressure fluid flow is high-pressure water flow, entanglement of the cellulosic fibers, which are hydrophilic fibers, proceeds smoothly, facilitating production.

[0053] The weight of the entire nonwoven fabric is, for example, 20 g / m 2 More than 80g / m 2 Below, especially 30g / m 2 More than 70g / m 2 Below, more particularly 40 g / m 2 More than 60g / m 2 The basis weight of the entire nonwoven fabric is appropriately selected depending on the application, etc. For example, when the nonwoven fabric is used as a covering sheet for a cosmetic puff described later, the basis weight may be 20 g / m or less. 2 More than 60g / m 2 Below, especially 25g / m 2 More than 55g / m 2 Below, more particularly 40 g / m 2 More than 50g / m 2 For example, when the nonwoven fabric is used as a liquid-impregnated skin covering sheet such as a cosmetic face mask, the basis weight may be 30 g / m or less. 2 More than 100g / m 2 Below, especially 35g / m 2 More than 50g / m 2 When the nonwoven fabric is used as a wet wiper for personal or object use, the basis weight is 30 g / m 2 More than 100g / m 2 Below, especially 40g / m 2 More than 90g / m 2 It may be the following:

[0054] The nonwoven fabric of this embodiment has a value (hereinafter, for convenience, also referred to as "stress index") obtained by dividing the stress at 10% elongation in the CD direction (transverse direction) in a wet state by the basis weight, measured in accordance with JIS L 1913:2010 6.3, of 0.015 (N / 50 mm) / (g / m 2 ) or more 0.050(N / 50mm) / (g / m 2) or less. By selecting the first and second cellulose fibers, particularly the second cellulose fibers, and designing the first and second fibrous layers so that the stress index satisfies this range, the first cellulose fibers are entangled with the second cellulose fibers, thereby more firmly fixing the first cellulose fibers. As a result, twisting that occurs when the nonwoven fabric is rubbed against an object can be reduced, and the handleability and dimensional stability of the nonwoven fabric tend to improve. Furthermore, a stress index within this range is thought to reduce the degree of freedom of the first cellulose fibers in the first fibrous layer. As a result, fiber movement when rubbing against an object is suppressed, the mean coefficient of friction variation (MMD), described below, is reduced, and surface roughness is thought to be reduced. The stress index is particularly 0.017 (N / 50mm) / (g / m 2 ) or more 0.048(N / 50mm) / (g / m 2 ) or less, more particularly 0.020 (N / 50mm) / (g / m 2 ) or more 0.045(N / 50mm) / (g / m 2 ) or less.

[0055] For example, in the nonwoven fabric of this embodiment, the basis weight of the first fiber layer is 7 g / m 2 More than 30g / m 2 The weight of the second fiber layer is 7 g / m or less. 2 More than 30g / m 2 The weight of the entire nonwoven fabric is 30 g / m or less. 2 More than 80g / m 2 If the stress index is less than 0.029 (N / 50mm) / (g / m 2 ) or more 0.050(N / 50mm) / (g / m 2 ) or less, especially 0.030 (N / 50mm) / (g / m 2 ) or more 0.045(N / 50mm) / (g / m 2 ) or less, more particularly 0.031 (N / 50 mm) / (g / m 2 ) or more 0.043(N / 50mm) / (g / m 2) or less. A nonwoven fabric having a basis weight and stress index within this range tends to enable lighter and smoother wiping and to have improved wiping properties, particularly when impregnated with liquid and used for wiping purposes such as cosmetic puffs and wiping sheets. This is thought to be because a stress index within the above range ensures the smoothness of the nonwoven fabric surface and prevents twisting during wiping, and because the basis weight is relatively small, there are many voids between the fibers, making it easy for wiped dirt and other contaminants to be captured in these voids.

[0056] The surface condition of the nonwoven fabric of this embodiment can be measured and evaluated using the Kawabata Evaluation System (KES) method, which is a method for measuring and objectively evaluating the texture of a fabric. Specifically, the surfaces of the first A fiber layer and the first B fiber layer of the nonwoven fabric of this embodiment are used as measurement surfaces, and the mean coefficient of friction (MIU) and the variation in the mean coefficient of friction (sometimes referred to as the mean deviation of the coefficient of friction μ, also referred to as MMD) are measured using the KES method. MIU indicates the degree of friction, i.e., slipperiness; a higher MIU indicates greater friction and less slipperiness. MMD indicates the variation in friction; a larger MIU indicates a rougher surface. The device used to measure the variation in the mean coefficient of friction is not particularly limited, as long as it is capable of measuring surface friction based on the KES method. For example, a friction feel tester ("KES-SE," manufactured by Kato Tech Co., Ltd.) or an automated surface tester ("KES-FB4-AUTO-A," manufactured by Kato Tech Co., Ltd.) can be used.

[0057] In the nonwoven fabric of this embodiment, the first A fiber layer surface and the first B fiber layer surface may have the same mean coefficient of friction (MIU) and mean coefficient of friction variation (MMD), or may have different MIU and MMD. When the surfaces of the two fiber layers have different MIU and MMD, the surface with the larger MIU (conveniently referred to as surface X) has a higher mean coefficient of friction in the MD direction (MD-MIU) when dry. X ) may be, for example, 0.2000 or less, particularly 0.1900 or less, more particularly 0.1800 or less, and the average coefficient of friction in the CD direction when dry (CD-MIU X) may be, for example, 0.1900 or less, particularly 0.1800 or less, and more particularly 0.1700 or less. In addition, in the nonwoven fabric of this embodiment, the variation of the average coefficient of friction in the MD direction (MD-MMD) of the surface X in a dry state having a larger MIU X ) may be, for example, 0.0110 or less, particularly 0.0090 or less, more particularly 0.0070 or less, and the variation of the average coefficient of friction in the CD direction (CD-MMD) of the surface X when dry X ) may be, for example, 0.0120 or less, particularly 0.0100 or less, and more particularly 0.0080 or less. Furthermore, the average value (MMMD) of the average variation in the average friction coefficient in the MD direction and the average variation in the average friction coefficient in the CD direction of the surface X of the nonwoven fabric of this embodiment when dry is AVE-X ) may be, for example, 0.0120 or less, particularly 0.0100 or less, and more particularly 0.0080 or less.

[0058] When both surfaces of the nonwoven fabric of this embodiment have different MIU and MMD, the surface with the smaller MIU (conveniently referred to as surface Y) has a lower average coefficient of friction in the MD direction (MD-MIU) when dry. Y ) may be, for example, 0.1700 or less, particularly 0.1600 or less, more particularly 0.1500 or less, and the average coefficient of friction in the CD direction when dry (CD-MIU Y ) may be, for example, 0.1800 or less, particularly 0.1700 or less, and more particularly 0.1600 or less. In addition, the nonwoven fabric of this embodiment has a smaller MIU when the surface Y has a smaller variation in the average coefficient of friction in the MD direction (MD-MMD Y ) may be, for example, 0.0100 or less, particularly 0.0080 or less, more particularly 0.0060 or less, and the variation of the average coefficient of friction in the CD direction (CD-MMD) of the surface Y when dry Y ) may be, for example, 0.0110 or less, particularly 0.0090 or less, and more particularly 0.0070 or less. Furthermore, the average value of the variation in the average friction coefficient in the MD direction and the variation in the average friction coefficient in the CD direction (MMMD) of the surface Y of the nonwoven fabric of this embodiment when dry is AVE-Y ) may be, for example, 0.0100 or less, particularly 0.0080 or less, and more particularly 0.0060 or less.

[0059] The surfaces of the 1A fiber layer and the 1B fiber layer may have different MIU and MMD, for example, when the 1a cellulosic fibers and the 1b cellulosic fibers have different fiber diameters. Similarly, even if the 1A fiber layer and the 1B fiber layer have the same structure, the respective fiber layers may have different MIU and MMD depending on the manufacturing conditions of the nonwoven fabric. In this case, either the 1A fiber layer or the 1B fiber layer has a surface X with an MD-MIU within the above range. X , CD-MIU X , MD-MMD X , CD-MMD X and MMD AVE-X The other layer has a surface Y within the above range. Y , CD-MIU Y , MD-MMD Y , CD-MMD Y and MMD AVE-Y The layer that forms surfaces X and Y may be either the 1A fiber layer or the 1B fiber layer, and in one embodiment, the 1A fiber layer may form surface X, and in another embodiment, the 1A fiber layer may form surface Y.

[0060] The nonwoven fabric of this embodiment is MMD AVE-X and MMD AVE-Y The average of MMD AVE may be, for example, 0.0100 or less, particularly 0.0095 or less, and more particularly 0.0090 or less. The MMD, which is the average value of the average variation of the average friction coefficient in the MD direction and the average variation of the average friction coefficient in the CD direction of the two surfaces of the nonwoven fabric when dry, AVE When the MMD is within this range, a laminated nonwoven fabric can be obtained in which the MMD of one side is not excessively small or large, and the feel and wiping properties on both sides are not excessively different.

[0061] (Nonwoven fabric manufacturing method) Next, a method for producing the nonwoven fabric of this embodiment will be described. The nonwoven fabric of this embodiment is preparing a 1A fiber web containing 1a cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1A fiber web; preparing a 1B fiber web containing 1b cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1B fiber web; preparing a second fiber web containing second cellulosic fibers in an amount of 40% by mass or more and 100% by mass or less, based on the total mass of the second fiber web, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more, an average fiber diameter of 7.0 μm or more and 25 μm or less, an average fiber diameter larger than the average fiber diameters of the 1a cellulosic fibers and the 1b cellulosic fibers, and having standard strength and wet strength larger than those of the 1a cellulosic fibers and the 1b cellulosic fibers; superposing the first A fiber web, the second fiber web, and the first B fiber web in this order to prepare a laminated fiber web; and The laminated fiber web is subjected to an entanglement treatment using a high-pressure fluid flow to entangle the fibers. It can be produced by a production method.

[0062] The types and basis weights of the fibers contained in the 1A fiber web / 1B fiber web and the 2nd fiber web are the same as those explained in relation to the 1A fiber layer / 1B fiber layer (or the 1st fiber layer collectively referred to as the 2nd fiber layer), and therefore will not be explained here.

[0063] The 1A fibrous web, the 1B fibrous web, and the second fibrous web can be produced by a known method. The form of each fibrous web may be any selected from the group consisting of parallel webs, cross webs, carded webs such as semi-random webs and random webs, air-laid webs, wet-laid paper webs, and spunbonded webs. The 1A fibrous web and the 1B fibrous web may have different forms from each other, or the 1A fibrous web and the 1B fibrous web may have the same form but different from the second fibrous web, or the 1A fibrous web, the 1B fibrous web, and the second fibrous web may be different from each other.

[0064] The first fiber web, the first fiber web, and the second fiber web are overlapped with each other so that the second fiber web is positioned between the first fiber web and the first fiber web to form a laminated fiber web. The laminated fiber web is subjected to a treatment to entangle the fibers. The treatment to entangle the fibers may be, for example, an entanglement treatment using a high-pressure fluid flow.

[0065] In the high-pressure fluid flow treatment, the high-pressure fluid is, for example, a high-pressure gas such as compressed air, or a high-pressure liquid such as high-pressure water. In the production of nonwoven fabrics, a hydroentanglement treatment using high-pressure water as the high-pressure fluid is often used, and in this embodiment, the hydroentanglement treatment is preferably used from the viewpoint of ease of implementation, etc. Below, a production method using high-pressure water (hereinafter also simply referred to as "water flow") as the high-pressure fluid will be described.

[0066] The hydroentanglement treatment is carried out by placing the laminated fiber web on a support and spraying a columnar water stream onto it. For example, the support is preferably a plain weave support of 80 mesh or more and 100 mesh or less. The hydroentanglement treatment may be carried out by spraying water streams at a water pressure of 1 MPa or more and 15 MPa or less onto the front and back surfaces of the laminated fiber web one to five times each from nozzles having orifices with a pore size of 0.05 mm or more and 0.5 mm or less, spaced 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, more preferably 1 MPa or more and 7 MPa or less. After spraying the water jet, a drying treatment is carried out, whereby the nonwoven fabric of this embodiment can be obtained.

[0067] In hydroentanglement, the first water jet controls the formation of the nonwoven fabric. Therefore, for example, when it is expected that the surface of the 1A fiber layer will be in contact with human skin or an object, it is preferable to expose the 1A web to the water jet first. This is thought to facilitate the establishment and maintenance of the 1A fiber layer prior to the 1B fiber layer and the 2nd fiber layer, thereby favorably affecting the smoothness and texture of the 1st fiber layer. More specifically, when the fiber diameter of the 1a cellulosic fibers is smaller than that of the 1b cellulosic fibers, spraying the water jet first on the 1A fiber web tends to produce a nonwoven fabric with a well-established fiber layer that exhibits the soft feel provided by the finer fibers.

[0068] When the hydroentanglement treatment is completed by spraying once on the 1A fibrous web side and once on the 1B fibrous web side, or when the final water jet is applied to the 1B fibrous web side, the 1A fibrous web comes into contact with the nonwoven fabric support or the like during the final water jet. The fibrous web in contact with the nonwoven fabric support is susceptible to the reduced pressure that draws in and drains the sprayed water, which can reduce the water flow marks formed on the 1A fibrous web side, and this can result in the 1A fibrous layer being smoother than the 1B fibrous layer.

[0069] (Uses of the nonwoven fabric of this embodiment) The nonwoven fabric of this embodiment can be used for various purposes, and is particularly preferably used as a covering sheet for a cosmetic puff or a liquid-impregnated sheet. These uses are described below.

[0070] [Cosmetic puff covering sheet] The nonwoven fabric of this embodiment is preferably used as a covering sheet for a cosmetic puff having a padding layer and a covering sheet covering the padding layer. When using the nonwoven fabric of this embodiment, either the 1A fiber layer or the 1B fiber layer is exposed on the front and back surfaces of the cosmetic puff, i.e., either the 1A fiber layer or the 1B fiber layer is positioned on the outside. Therefore, when the 1A fiber layer and the 1B fiber layer have the same configuration, both the front and back surfaces of the cosmetic puff have the smooth and dense surface of the 1A fiber layer with the same configuration, so that regardless of which side is used for wiping or patting, the user can be provided with a relatively similar feel or comfort.

[0071] If the first A fiber layer and the first B fiber layer have different compositions, or if there is a significant difference in MIU and MMD between these fiber layers, the nonwoven fabric of this embodiment may be arranged so that one surface of the filling layer is the surface of the first A fiber layer and the other surface is the surface of the first B fiber layer. Because such a cosmetic puff can have different textures on both sides due to differences in the composition or MIU of the fiber layers, it is possible to use different surfaces of the cosmetic puff depending on the user's preference, for example, to use one surface as a wiping surface when wiping off cleansing cream and the other surface as a patting surface for lotion (or vice versa).

[0072] [Liquid-impregnated sheet] The nonwoven fabric of this embodiment is preferably used as a liquid-impregnated sheet that is impregnated with a liquid. The type of liquid and the amount of impregnation are selected depending on the application. For example, when the liquid-impregnated sheet is provided as a wet wiping sheet for personal use, the sheet may be impregnated with water or an aqueous solution containing a cleansing component in an amount of 100 parts by mass or more and 1,000 parts by mass or less per 100 parts by mass of the nonwoven fabric. More specifically, wet wiping sheets for personal use are provided as, for example, hand wipes, baby wipes, menstrual wipes, makeup removers, face wash sheets, antiperspirant sheets, and nail removers.

[0073] When the liquid-impregnated sheet is provided as a liquid-impregnated skin covering sheet for personal use, such as a face mask for personal use or an exfoliating sheet, the liquid containing an active ingredient (e.g., a cosmetic) may be impregnated in an amount of 150 to 2500 parts by mass, preferably 400 to 2000 parts by mass, per 100 parts by mass of the nonwoven fabric. Examples of the active ingredient include, but are not limited to, moisturizing ingredients, exfoliating ingredients, cleansing ingredients, antiperspirant ingredients, fragrance ingredients, whitening ingredients, blood circulation promoting ingredients, UV protection ingredients, and slimming ingredients.

[0074] The face mask is provided in a shape suitable for covering the face, and further has openings or cutouts formed by punching, for example, in areas corresponding to the eyes, nose, and mouth, as needed. Alternatively, the face mask may be shaped to cover only a portion of the face (for example, the eyes, mouth, nose, or cheeks). Alternatively, the face mask may be provided as a set consisting of a sheet that covers the area around the eyes and a sheet that covers the area around the mouth, or as a set of sheets that separately cover three or more areas.

[0075] Alternatively, the liquid-impregnated sheet may be used for object applications, and may be attached to an object for the purpose of supplying liquid to the object or keeping the object moist. Specifically, the liquid-impregnated sheet of the present invention may be impregnated with a detergent or the like, for the purpose of softening or separating stubborn dirt from the object. When the nonwoven fabric of this embodiment is used for object applications, the surface of the first A fiber layer or first B fiber layer, which is smooth, dense, and has a large number of constituent fibers, is brought into contact with the object, allowing for light and smooth wiping of the object and improving its ability to conform to small objects and objects with uneven surfaces, allowing for thorough wiping. [Example]

[0076] Hereinafter, this embodiment will be described with reference to examples. The abbreviations in parentheses are used in the tables. Cellulosic fibers i to ii and cellulose long fibers were prepared as fibers constituting comparative examples.

[0077] First cellulosic fiber 1 (rayon 0.6T): Viscose rayon (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a nominal fineness of 0.6 dtex, an average fiber diameter of 7 μm, a chrysanthemum-shaped fiber cross section, and a fiber length of 32 mm was prepared. First cellulosic fiber 2 (rayon 0.3T): Viscose rayon (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a nominal fineness of 0.3 dtex, an average fiber diameter of 5 μm, a chrysanthemum-shaped fiber cross section, and a fiber length of 32 mm was prepared. First cellulosic fiber 3 (rayon 1.1T): Viscose rayon (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a nominal fineness of 1.1 dtex, an average fiber diameter of 9.7 μm, a chrysanthemum-shaped fiber cross section, and a fiber length of 38 mm was prepared. First cellulosic fiber 4 (rayon 1.4T): Viscose rayon (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a nominal fineness of 1.4 dtex, an average fiber diameter of 11.4 μm, a chrysanthemum-shaped fiber cross section, and a fiber length of 44 mm was prepared. First cellulosic fiber 5 (cupra 1.4T): Cupra (trade name: Bemberg, manufactured by Asahi Kasei Corporation) produced by the cuprammonium method was prepared, having a nominal fineness of 1.4 dtex, an average fiber diameter of 11.5 μm, and a fiber length of 38 mm.

[0078] Second cellulosic fiber 1 (Lyocell 1.7T): Lyocell (trade name: Lyocell, manufactured by Lenzing) having a nominal fineness of 1.7 dtex, an average fiber diameter of 12 μm, a circular fiber cross section, and a fiber length of 38 mm was prepared. Second cellulosic fiber 2 (Lyocell 0.9T): Lyocell (trade name: Lyocell, manufactured by Lenzing) having a nominal fineness of 0.9 dtex, an average fiber diameter of 8.8 μm, a circular fiber cross section, and a fiber length of 34 mm was prepared. Second cellulosic fiber 3 (Lyocell 3.3T): Lyocell (trade name: Lyocell, manufactured by Lenzing) having a nominal fineness of 3.3 dtex, an average fiber diameter of 16.8 μm, a circular fiber cross section, and a fiber length of 51 mm was prepared. Second cellulosic fiber 4 (Lyocell 6.7T): Lyocell (trade name: Lyocell, manufactured by Lenzing) having a nominal fineness of 6.7 dtex, an average fiber diameter of 24 μm, a circular fiber cross section, and a fiber length of 60 mm was prepared. Second cellulose fiber 5 (Lyocell 1.7T-2): Lyocell (trade name: Lyocell, manufactured by Lenzing) was prepared, having a nominal fineness of 1.7 dtex, an average fiber diameter of 12.4 μm, a circular cross section, and a fiber length of 38 mm. The second cellulose fiber 5 has the same fineness and fiber length as the second cellulose fiber 1, but is obtained at a different time.

[0079] Cellulose fiber i (rayon 1.7T): Viscose rayon (trade name: Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a fineness of 1.7 dtex, an average fiber diameter of 11.9 μm, a chrysanthemum-shaped cross section, and a fiber length of 40 mm was prepared.

[0080] The standard strength, wet strength and elongation of each cellulosic fiber are shown in Tables 1 and 2.

[0081] Other fiber I (PET1.45T): Polyethylene terephthalate (trade name: T403, manufactured by Toray Industries, Inc.) having a fineness of 1.45 dtex, an average fiber diameter of 12 μm, a circular fiber cross section, and a fiber length of 38 mm was prepared.

[0082] [Table 1]

[0083] [Table 2]

[0084] (Examples 1 and 2) The fibers shown in Table 3 were used as the 1a cellulosic fiber, 1b cellulosic fiber, and second cellulosic fiber, respectively, and a parallel carding machine was used to produce the 1A fiber web, 1B fiber web, and second fiber web, each with the target diameters shown in Table 2. In Table 2, when one type of fiber was used as each of the 1a cellulosic fiber and the 1b cellulosic fiber, the type of fiber is listed in the columns for the 1a1 cellulosic fiber and the 1b1 cellulosic fiber.

[0085] A second fiber web was layered on the first fiber web, and the first fiber web was layered on the second fiber web 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 m / min. A water stream of 2.5 MPa was sprayed once onto the surface of the first fiber web, and then a water stream of 2.5 MPa was sprayed once onto the surface of the first fiber web. The nozzle used for the hydroentanglement treatment was a nozzle with 0.1 mm orifices spaced 0.6 mm apart, and the distance between the nozzle and the fiber web during treatment was 20 mm.

[0086] Next, the fiber web after the hydroentanglement treatment was subjected to a drying treatment using a hot air penetration type heat treatment machine set at 80°C, to obtain the laminated nonwoven fabrics of Examples 1 and 2, respectively.

[0087] (Comparative Examples 1 and 2) Laminated nonwoven fabrics were produced in the same manner as in Examples 1 and 2, except that the 1a cellulosic fibers / 1b cellulosic fibers constituting the 1A / 1B fiber layers and the fibers constituting the second fiber layer were the fibers shown in Table 3. The resulting nonwoven fabrics are designated Comparative Examples 1 and 2. In Table 2, for convenience, the fibers constituting the second fiber layer are listed in the column for second cellulosic fibers.

[0088] (Examples 3 to 11, Comparative Examples 3 to 4) Laminated nonwoven fabrics were produced in the same manner as in Examples 1 and 2, except that the 1a cellulosic fibers / 1b cellulosic fibers constituting the 1A / 1B fiber layers and the fibers constituting the second fiber layer were the fibers shown in Tables 3 and 4, respectively, and the basis weights of each fiber layer were as shown in Tables 3 and 4. The resulting nonwoven fabrics are referred to as Examples 3 to 11. In Example 10, the two types of cellulosic fibers used as the 1a cellulosic fibers are shown in Table 4 as 1a1 and 1a2 cellulosic fibers, respectively, and the two types of cellulosic fibers used as the 1b cellulosic fibers are shown in Table 4 as 1b1 and 1b2 cellulosic fibers, respectively. In Example 11, in addition to the 1a cellulosic fibers / 1b cellulosic fibers constituting the 1A / 1B fiber layers and the fibers constituting the second fiber layer, PET1.45T constituting the 1A / 1B fiber layers is shown in Table 4 as another fiber. In addition, in the comparative examples in Tables 3 and 4, for convenience, the fibers constituting the first fiber layer and the second fiber layer are listed in the column for first cellulosic fiber.

[0089] The nonwoven fabrics obtained in each Example and Comparative Example were evaluated as follows. The evaluation results are shown in Tables 5 and 6. Furthermore, electron microscope photographs (100x magnification) of the cross sections of the nonwoven fabrics obtained in Example 1, Comparative Example 1, and Comparative Example 2 are shown in Figs. 1 to 3. Furthermore, Fig. 4 shows an electron microscope photograph in which each bent or twisted portion of the second cellulose fiber observed in the second fiber layer of the nonwoven fabric obtained in Example 1 is surrounded by a dashed line.

[0090] <Thickness of nonwoven fabric> The thickness of the nonwoven fabric was measured using a thickness gauge (THICKNESS GAUGE Model CR-60A (trade name) manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) while a load of 294 Pa or 1.96 kPa was applied to the nonwoven fabric. The bulk density of the nonwoven fabric was calculated based on the basis weight of the nonwoven fabric and the thickness of the nonwoven fabric measured under a load of 294 Pa.

[0091] <Strength and elongation> Tensile strength was measured in accordance with JIS L 1913:2010 6.3 using a constant-speed tension tensile tester under the conditions of a sample width of 5 cm, a grip spacing of 10 cm, and a tensile speed of 30±2 cm / min. The load at break (tensile strength), elongation, and stress at 10% elongation (the force required to elongate 10%) were measured. The tensile test was conducted in the machine direction (MD) and the cross direction (CD) of the nonwoven fabric. The evaluation results are all shown as the average of the values ​​measured for three samples. The tensile strength in the dry state (standard state) and in the wet state were measured. The strength and elongation in the wet state were measured by wetting the sample according to the method specified in JIS L 1913:2010 6.3, and also by impregnating 100 parts by mass of the sample with 250 parts by mass of distilled water. The stress at 10% elongation in the CD direction, measured after wetting using the method specified in JIS, was divided by the basis weight to obtain a stress index.

[0092] <Dynamic friction coefficient and coefficient of variation> The mean coefficient of friction (MIU) and its variation (MMD) were measured using a friction tester (KES-SE, Kato Tech Co., Ltd.). A 5 cm × 10 cm nonwoven fabric was prepared as a test piece. Two test pieces were prepared, one with the long side aligned in the MD direction and the other aligned in the CD direction. A piano wire sensor (Kato Tech Co., Ltd.) was used as the contact terminal of the measuring instrument. The test piece was fixed to the measurement table, and a contact terminal (25 g) was moved 30 mm in one direction on the surface of the first A fiber layer of the test piece at a speed of 1.0 mm / sec. The MMD was evaluated between points 5 mm and 25 mm from the starting point of the movement. Three measurements were performed on the test piece with the long side aligned in the MD direction, and three measurements were performed on the test piece with the long side aligned in the CD direction. The average of the three measurements was used as the MMD in each direction. The same measurement was also performed on the surface of the first B fiber layer.

[0093] <Adhesion> Adhesion force was measured using a static and dynamic friction measuring instrument (Tribomaster TL201Ts, manufactured by Trinity Lab Co., Ltd.). Sample pieces measuring 12 cm x 5 cm were prepared. The long sides of the sample pieces were in the MD and CD directions of the nonwoven fabric. Artificial skin (24 cm long x 12 cm wide, product name: BIO SKIN PLATE, manufactured and sold by Bealux Co., Ltd.) was attached to the measuring table of the measuring instrument (sliding table type).

[0094] 100 parts by mass of the sample piece was impregnated with 800 parts by mass of distilled water, and the edge of the short side of the sample piece (referred to as the "clip end") was clamped horizontally with the clip of the measuring machine. The measurement table was moved so that only an area of ​​8 cm long x 5 cm short of the sample from the edge opposite the clip end (referred to as the "non-clipped end") overlapped the artificial skin. The measurement table was moved parallel to the long side of the sample, away from the clip end, at a speed of 10 mm / sec along the long side of the sample, and the maximum resistance force (N) was read. For each example, five sample pieces were measured in both the MD and CD directions. Excluding the lowest and highest values, the average of the maximum resistance forces (N) for each direction was calculated, and this was defined as the adhesion strength.

[0095] <Wipeability> Lipstick wiping properties were evaluated by the following method. Sample size: 5cm x 12cm (MD x CD) Impregnation solution: distilled water Impregnation amount: 500% of the mass of the laminated nonwoven fabric Number of times the measurement table moves back and forth: 2 times Measuring equipment: Static and dynamic friction measurement TL201tT (manufactured by Trinity Lab Co., Ltd.) Measurement conditions: Load: 100g, Speed: 10mm / s, Travel distance: 100mm ·Measurement method (1) Draw three lines, 10 cm long and 0.5 cm apart, on the artificial skin with lipstick. (2) Wrap the flat contact with a laminated nonwoven fabric impregnated with a chemical solution. (3) After moving the measurement table back and forth twice, remove the laminated nonwoven fabric. (4) Visually inspect the surface of the laminated nonwoven fabric and evaluate it according to the following criteria:

[0096] Evaluation criteria ○: The lines on the three lipsticks were wiped off at the area that had been in contact with the test piece, and they are suitable for practical use. △: The lines of the three lipsticks were wiped off in the areas that had been in contact with the test piece, but some wiping spots were observed, making it unsuitable for practical use.

[0097] <Wiping resistance> In the wiping test, the coefficient of dynamic friction was measured during two round trips, one on each way, and the other on the return trip, and the average of the four measured values ​​was calculated. This measurement was performed on three test pieces, and the average of these values ​​was then used as the wiping resistance value.

[0098] [Table 3]

[0099] [Table 4]

[0100] [Table 5]

[0101] [Table 6]

[0102] From the electron microscope photographs of Figures 1 to 3, the number of fibers (areas surrounded by dashed lines in the figures) in which the second cellulose fiber had bent and / or twisted portions in Example 1, Comparative Example 1, and Comparative Example 2 was counted.It was found that there were at least seven such portions in Example 1, none in Comparative Example 1, and less than seven in Comparative Example 2.

[0103] In a comparison between Example 1 and Comparative Example 1, and Example 1 and Comparative Example 2, in which the first A fiber layer and the first B fiber layer have the same configuration but the second fiber layer has a different configuration, all of the Examples showed higher stress at 10% elongation when wet. In Example 1, Comparative Example 1, and Comparative Example 2, the surfaces with larger MIU were all the surfaces of the first B fiber layer, and the surfaces with smaller MIU were all the surfaces of the first A fiber layer. Therefore, in a comparison between Example 1 and Comparative Example 1, and Example 1 and Comparative Example 2, the surface physical properties were compared between the first A fiber layers and between the first B fiber layers. Example 1 showed generally smaller MIU and MMD than Comparative Examples 1 and 2 (however, the MD-MMD of the first B fiber layer in Comparative Example 1 was lower). B (The MMD of the nonwoven fabric of Example 1 was larger than that of Example 1.) In addition, the nonwoven fabric of Example 1 had a lower MMD than any of the comparative examples. AVE was smaller.

[0104] In Example 2, the surface with a larger MIU was the surface of the 1A fiber layer, and the surface with a smaller MIU was the surface of the 1B fiber layer. Therefore, when the surface properties of the 1A fiber layer in Example 1 and the 1B fiber layer in Example 2, and the surface properties of the 1B fiber layer in Example 1 and the 1A fiber layer in Example 2, were compared, Example 2 showed a larger MIU and MMD. This is thought to be because the fiber diameters of the 1a and 1b cellulosic fibers constituting the 1A and 1B fiber layers in Example 2 were larger than those in Example 1. Furthermore, Example 2 had a smaller MMD than Example 1. AvE showed.

[0105] Example 1 exhibited better wiping properties than Comparative Example 1, and also exhibited lower wiping resistance than Comparative Example 1. On the other hand, the adhesion strength of Example 1 was lower than that of Comparative Example 1, but this was not a problem in practical use.

[0106] In Examples 3 and 4, the configurations of the 1A and 1B fiber layers were the same as in Example 1, but the fiber diameter of the second cellulosic fiber constituting the second fiber layer was different from that of Example 1. Both Examples 3 and 4 exhibited smaller MIU and MMD than Comparative Example 1, in which the second fiber layer was composed of cellulosic fibers other than the second cellulosic fibers.

[0107] In Examples 6 and 7, the fiber diameter of the first cellulosic fibers constituting the 1A and 1B fiber layers was larger than that of Examples 1 and 2. In Examples 1, 2, 6, and 7, MIU and MMD tended to increase in proportion to the fiber diameter. Furthermore, in a comparison between Example 6 and Comparative Example 4 (in which the second fiber layer was composed of cellulosic fibers other than the second cellulosic fibers), Example 6 had smaller CD-MMD and MMD than Comparative Example 4. AvE These results confirmed that not only the fiber diameter of the first cellulosic fiber but also the physical properties of the second cellulosic fiber affect the surface smoothness and frictional properties of the laminated nonwoven fabric.

[0108] In Comparative Example 3, the 1A and 1B fiber layers were made of a cellulose fiber (Lyocell 0.9T) that had a small fiber diameter but high strength in both dry and wet conditions. In Comparative Example 3, the fiber diameter of the first cellulose fiber was larger than that of the Lyocell 0.9T used in Comparative Example 3, and the MMD was larger. AvE-A and MMD AvE-B , and MMD AvE This confirmed that the surface smoothness and frictional properties of the laminated nonwoven fabric are affected not only by the fiber diameter of the cellulosic fibers located on the surface, but also by their mechanical strength.

[0109] In Examples 8 and 9, the basis weight of one or more fiber layers is made larger or smaller than that of Example 2, and the basis weight of the entire laminated nonwoven fabric is made larger or smaller than that of Example 2. In Examples 8 and 9, the average fiber diameter of the first cellulose fiber is smaller than that of Comparative Example 1, and the MMD is smaller than that of Comparative Example 1. AvE-A and MMD AvE-B , and MMDAvE Furthermore, Example 8 exhibited a greater adhesion than Example 2. This is thought to be due to the fact that the basis weight of the 1A and 1B fiber layers was greater than that of Example 2, the number of fibers constituting the fibers was greater, and this resulted in more uniform contact with the target surface.

[0110] In Example 10, the first and first-B fiber layers were constructed using two types of fibers with different fiber diameters as the first cellulosic fiber. In Example 11, 30 mass % of the fibers constituting the first and first-B fiber layers were fibers other than cellulosic fibers. These examples also had smaller MMD values ​​than Comparative Example 1, in which the first cellulosic fiber had a smaller average fiber diameter. AvE-A and MMD AvE-B , and MMD AvE showed.

[0111] The present embodiment includes the following aspects. (Aspect 1) a first A fiber layer, a first B fiber layer, and a second fiber layer located between the first A fiber layer and the first B fiber layer; the 1A fiber layer has a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and contains 1a cellulosic fibers having an average fiber diameter of 0.1 μm or more and 12.0 μm or less in a proportion of 70% by mass or more and 100% by mass or less; the 1B fiber layer has a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and contains 1b cellulosic fibers having an average fiber diameter of 0.1 μm or more and 12.0 μm or less in a proportion of 70% by mass or more and 100% by mass or less, the second fiber layer contains second cellulosic fibers in a proportion of 40% by mass or more and 100% by mass or less, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more and an average fiber diameter of 7.0 μm or more and 25 μm or less, the average fiber diameter of the 1a cellulosic fibers and the 1b cellulosic fibers is smaller than the average fiber diameter of the second cellulosic fibers; the standard strength and wet strength of the 1a cellulosic fiber and the 1b cellulosic fiber are smaller than the standard strength and wet strength of the second cellulosic fiber; The first A fiber layer, the second fiber layer, and the first B fiber layer are integrated by entanglement of the fibers. (Aspect 2) The laminated nonwoven fabric of aspect 1, wherein seven or more second cellulosic fibers having bent portions and / or twisted portions are observed in the second fiber layer in an area of ​​1280 μm × 960 μm in an electron microscope photograph of a cross section of the laminated nonwoven fabric magnified 100 times. (Aspect 3) 3. The laminated nonwoven fabric of claim 1 or 2, wherein the standard strength of the 1a cellulosic fiber and the 1b cellulosic fiber is at least 0.4 cN / dtex less than the standard strength of the second cellulosic fiber, or the wet strength of the 1a cellulosic fiber and the 1b cellulosic fiber is at least 0.4 cN / dtex less than the wet strength of the second cellulosic fiber. (Aspect 4) The laminated nonwoven fabric of any one of aspects 1 to 3, wherein the 1a cellulosic fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, the 1b cellulosic fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, and the second cellulosic fibers have an average fiber diameter of 10 μm or more and 25 μm or less. (Aspect 5) 5. The laminated nonwoven fabric of any one of Aspects 1 to 4, wherein the second cellulosic fibers have a standard strength of 3.0 cN / dtex or greater and / or a wet strength of 2.2 cN / dtex or greater. (Aspect 6) 6. The laminated nonwoven fabric of claim 1, wherein either or both of the 1A fiber layer and the 1B fiber layer contain a cellulosic fiber A other than the 1a cellulosic fiber and the 1b cellulosic fiber, and all of the constituent fibers of either or both of the 1A fiber layer and the 1B fiber layer are cellulosic fibers. (Aspect 7) The laminated nonwoven fabric of any one of aspects 1 to 6, wherein the second fiber layer contains cellulosic fibers B other than the second cellulosic fibers, and all of the constituent fibers of the second fiber layer are cellulosic fibers. (Aspect 8) The laminated nonwoven fabric has a value of 0.015 (N / 50 mm) / (g / m2) when measured in accordance with JIS L 1913:2010 6.3 and calculated by dividing the stress at 10% elongation in the CD direction (cross direction) in a wet state by the basis weight. 2 ) or more 0.050(N / 50mm) / (g / m 2 8. The laminated nonwoven fabric of any one of Aspects 1 to 7, wherein: (Aspect 9) The laminated nonwoven fabric of any one of Aspects 1 to 8, wherein the ratio of the average fiber diameter of the 1a cellulosic fibers and the 1b cellulosic fibers to the average fiber diameter of the second cellulosic fibers is greater than 1 and less than 1.75. (Aspect 10) the 1a cellulosic fibers and / or the 1b cellulosic fibers are viscose rayon fibers; the second cellulosic fibers are solvent-spun cellulosic fibers; The laminated nonwoven fabric according to any one of Aspects 1 to 9. (Aspect 11) 11. A laminated nonwoven fabric for a liquid-impregnated sheet, comprising the laminated nonwoven fabric according to claim 1. (Aspect 12) preparing a 1A fiber web containing 1a cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1A fiber web; preparing a 1B fiber web containing 1b cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1B fiber web; preparing a second fiber web containing second cellulosic fibers in an amount of 40% by mass or more and 100% by mass or less, based on the total mass of the second fiber web, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more, an average fiber diameter of 7.0 μm or more and 25 μm or less, an average fiber diameter larger than the average fiber diameters of the 1a cellulosic fibers and the 1b cellulosic fibers, and having standard strength and wet strength larger than those of the 1a cellulosic fibers and the 1b cellulosic fibers; superposing the first A fiber web, the second fiber web, and the first B fiber web in this order to prepare a laminated fiber web; and A method for producing a laminated nonwoven fabric, comprising subjecting the laminated fiber web to an entanglement treatment using a high-pressure fluid stream to entangle the fibers. (Aspect 13) A method for producing a laminated nonwoven fabric according to aspect 12, wherein seven or more second cellulose fibers having bent portions and / or twisted portions are observed in the second fibrous web in an area of ​​1280 μm x 960 μm in an electron microscope photograph of the cross section of the second fibrous web magnified 100 times. (Aspect 14) 14. The method for producing a laminated nonwoven fabric of aspect 12 or 13, wherein the standard strength of the 1a cellulosic fiber and the 1b cellulosic fiber is at least 0.4 cN / dtex less than the standard strength of the second cellulosic fiber, or the wet strength of the 1a cellulosic fiber and the 1b cellulosic fiber is at least 0.4 cN / dtex less than the wet strength of the second cellulosic fiber. (Aspect 15) 15. The method for producing a nonwoven fabric according to any one of aspects 12 to 14, wherein the 1a cellulosic fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, the 1b cellulosic fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, and the second cellulosic fibers have an average fiber diameter of 10 μm or more and 25 μm or less. (Aspect 16) 16. The method for producing a laminated nonwoven fabric according to any one of aspects 12 to 15, wherein the second cellulosic fibers have a standard strength of 3.0 cN / dtex or more and / or a wet strength of 2.2 cN / dtex or more. [Industrial Applicability]

[0112] The nonwoven fabric of the present disclosure has a first fiber layer 1A and a first fiber layer 1B, each containing specific first cellulosic fibers and specific first b cellulosic fibers in specific proportions, and a second fiber layer containing specific second cellulosic fibers in a specific proportion between the first fiber layer 1A and the first fiber layer 1B. The nonwoven fabric has relatively high mechanical strength and smooth surfaces. Therefore, the nonwoven fabric of the present disclosure is useful for applications such as cosmetic puffs, which are applied to the skin in a liquid-impregnated state and / or rubbed against the skin.

Claims

1. a first A fiber layer, a first B fiber layer, and a second fiber layer located between the first A fiber layer and the first B fiber layer, the first A fiber layer has a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and contains 1a cellulosic fibers having an average fiber diameter of 0.1 μm or more and 12.0 μm or less in a proportion of 70% by mass or more and 100% by mass or less, the firstB fiber layer contains 70% by mass or more and 100% by mass or less of firstb cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less, the second fiber layer contains second cellulosic fibers in a proportion of 40% by mass or more and 100% by mass or less, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more and an average fiber diameter of 7.0 μm or more and 25 μm or less, the average fiber diameter of the first a cellulose fibers and the first b cellulose fibers is smaller than the average fiber diameter of the second cellulose fibers; the standard strength and wet strength of the first a cellulose fiber and the first b cellulose fiber are smaller than the standard strength and wet strength of the second cellulose fiber; The first A fiber layer, the second fiber layer, and the first B fiber layer are integrated by entanglement of the fibers.

2. 2. The laminated nonwoven fabric of claim 1, wherein seven or more second cellulose fibers having bent portions and / or twisted portions are observed in the second fiber layer in an area of ​​1280 μm x 960 μm in an electron microscope photograph of the cross section of the laminated nonwoven fabric magnified 100 times.

3. 2. The laminated nonwoven fabric of claim 1, wherein the standard strength of the first a cellulose fiber and the first b cellulose fiber is at least 0.4 cN / dtex less than the standard strength of the second cellulose fiber, or the wet strength of the first a cellulose fiber and the first b cellulose fiber is at least 0.4 cN / dtex less than the wet strength of the second cellulose fiber.

4. 2. The laminated nonwoven fabric according to claim 1, wherein the first a cellulose-based fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, the first b cellulose-based fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, and the second cellulose-based fibers have an average fiber diameter of 10 μm or more and 25 μm or less.

5. 2. The laminated nonwoven fabric of claim 1, wherein the second cellulosic fibers have a standard strength of 3.0 cN / dtex or greater and / or a wet strength of 2.2 cN / dtex or greater.

6. 2. The laminated nonwoven fabric according to claim 1, wherein either or both of the first A fiber layer and the first B fiber layer contain cellulosic fibers A other than the 1a cellulosic fibers and the 1b cellulosic fibers, and all constituent fibers of either or both of the first A fiber layer and the first B fiber layer are cellulosic fibers.

7. The laminated nonwoven fabric according to claim 1 , wherein the second fiber layer contains a cellulosic fiber B other than the second cellulosic fiber, and all constituent fibers of the second fiber layer are cellulosic fibers.

8. The laminated nonwoven fabric has a value of 0.015 (N / 50 mm) / (g / m) when measured in accordance with JIS L 1913:2010 6.3 and calculated by dividing the stress at 10% elongation in the CD direction (transverse direction) in a wet state by the basis weight. ２ ) or more 0.050 (N / 50mm) / (g / m ２ 2. The laminated nonwoven fabric according to claim 1, wherein the thickness of the laminated nonwoven fabric is 1 / 2 or less.

9. 2. The laminated nonwoven fabric of claim 1, wherein the ratio of the average fiber diameter of the first a cellulosic fibers and the first b cellulosic fibers to the average fiber diameter of the second cellulosic fibers is greater than 1 and less than 1.

75.

10. the 1a cellulosic fibers and / or the 1b cellulosic fibers are viscose rayon fibers; the second cellulosic fibers are solvent-spun cellulosic fibers; The laminated nonwoven fabric according to claim 1 .

11. A laminated nonwoven fabric for a liquid-impregnated sheet, comprising the laminated nonwoven fabric according to any one of claims 1 to 10.

12. preparing a 1A fiber web containing 1a cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1A fiber web; preparing a 1B fiber web containing 1b cellulosic fibers having a standard strength of 2.8 cN / dtex or less and / or a wet strength of 2.0 cN / dtex or less and an average fiber diameter of 0.1 μm or more and 12.0 μm or less in an amount of 70% by mass or more and 100% by mass or less, based on the total mass of the 1B fiber web; preparing a second fiber web containing second cellulosic fibers in an amount of 40% by mass or more and 100% by mass or less, based on the total mass of the second fiber web, the second cellulosic fibers having a standard strength of 2.4 cN / dtex or more and / or a wet strength of 1.9 cN / dtex or more, an average fiber diameter of 7.0 μm or more and 25 μm or less, an average fiber diameter larger than the average fiber diameters of the firsta cellulosic fibers and the firstb cellulosic fibers, and having standard strength and wet strength larger than those of the firsta cellulosic fibers and the firstb cellulosic fibers; The first A fiber web, the second fiber web, and the first B fiber web are superimposed in this order to prepare a laminated fiber web; and A method for producing a laminated nonwoven fabric, comprising subjecting the laminated fiber web to an entanglement treatment using a high-pressure fluid stream to entangle the fibers.

13. 13. The method for producing a laminated nonwoven fabric according to claim 12, wherein seven or more second cellulose fibers having bent portions and / or twisted portions are observed in an area of ​​1280 μm x 960 μm in an electron microscope photograph of the cross section of the second fiber web magnified 100 times.

14. 13. The method for producing a laminated nonwoven fabric according to claim 12, wherein the standard strength of the first a cellulose fiber and the first b cellulose fiber is at least 0.4 cN / dtex less than the standard strength of the second cellulose fiber, or the wet strength of the first a cellulose fiber and the first b cellulose fiber is at least 0.4 cN / dtex less than the wet strength of the second cellulose fiber.

15. 13. The method for producing a nonwoven fabric according to claim 12, wherein the first a cellulose-based fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, the first b cellulose-based fibers have an average fiber diameter of 0.1 μm or more and less than 10 μm, and the second cellulose-based fibers have an average fiber diameter of 10 μm or more and 25 μm or less.

16. The method for producing a laminated nonwoven fabric according to claim 12, wherein the second cellulosic fibers have a standard strength of 3.0 cN / dtex or more and / or a wet strength of 2.2 cN / dtex or more.

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