Nonwoven fabric for cleaning

Abstract

To provide a nonwoven fabric excellent in handleability when used by squeezing water and water wiping properties in a water-retaining state even if having a low basis weight.SOLUTION: The nonwoven fabric is a nonwoven fabric for cleaning having an adhesive region of a binder and containing hydrophobic fibers, wherein the ratio of the hydrophobic fibers to all fibers in the nonwoven fabric is 30 wt.% or more and the basis weight is 45g / m2 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a nonwoven cleaning fabric. [Background technology]

[0002] Nonwoven fabrics are used in a variety of applications, including cleaning products such as wipers, and various improvements have been made to nonwoven fabrics for cleaning to provide them with desirable properties such as absorbency and washability.

[0003] For example, Patent Document 1 (JP 2008-115476 A) discloses a nonwoven fabric that not only has high absorbency but also has washing durability that allows it to be washed for reuse, and also has improved antibacterial properties that prevent the growth of bacteria in a hygienic sense. This nonwoven fabric has a basis weight of 30 to 100 g / m and is formed from a fiber web that contains at least rayon fiber and additionally contains synthetic fiber. 2 The mesh-like nonwoven fabric is a nonwoven fabric in which an acrylic resin is applied twice to the front and back surfaces of the fiber web.

[0004] Patent Document 2 (JP 2022-082755 A) discloses a nonwoven fabric with excellent absorbency and washing durability, and a method for producing the same. This nonwoven fabric has a binder adhesive region, and the nonwoven fabric is cut at a randomly selected thickness direction from the adhesive region and divided into three equal parts in the thickness direction, each of which is designated as an upper layer portion, a lower layer portion, and a middle layer portion of the nonwoven fabric. Each portion contains a plurality of fiber bundles in which a plurality of single fibers are bound and integrated by the binder, and the total number of single fibers present in the fiber bundles satisfies Nu / Nc > 1.10 and Nb / Nc > 1.10, where Nu is the total number of fibers in the bundles in the upper layer portion, Nb is the total number of fibers in the bundles in the lower layer portion, and Nc is the total number of fibers in the bundles in the middle layer portion, respectively. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-115476 [Patent Document 2] Japanese Patent Publication No. 2022-082755 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 employs rayon fibers to improve the absorbency of nonwoven fabrics. However, because hydrophilic fibers such as rayon fibers penetrate deep into the fibers, a high content of hydrophilic fibers prevents sufficient moisture from being released when the nonwoven fabric is compressed and wrung, resulting in poor dehydration. Resource conservation is particularly required for nonwoven fabrics used in applications such as wipers, where hygiene is ensured by discarding the fabric after a certain period of use. Therefore, low-basis-weight nonwoven fabrics are desirable. However, low-basis-weight nonwoven fabrics have poor dehydration properties, and hydrophilic fibers that have penetrated deep into the fibers have low resilience, making the nonwoven fabric difficult to unfold after wringing, resulting in poor handling when used for cleaning. Furthermore, low-basis-weight nonwoven fabrics have a low fiber content, resulting in poor water retention and poor wiping properties. Patent Document 1 additionally contains synthetic fibers to ensure strength after liquid absorption, but the examples only produce low-basis-weight nonwoven fabrics with a high rayon fiber content.

[0007] In Patent Document 2, absorbency is ensured by reducing the number of fibers present in the fiber bundles bound by the binder inside the nonwoven fabric compared to the surface of the nonwoven fabric, but the ease of dehydration of the nonwoven fabric is not examined. Furthermore, in the examples of Patent Document 2, a nonwoven fabric with a low basis weight is not produced.

[0008] Therefore, the object of the present invention is to solve the problems of the conventional technology and to provide a nonwoven fabric that has excellent handling properties when squeezed out of water and excellent water wiping properties when retaining water, even when the fabric has a low basis weight. [Means for solving the problem]

[0009] As a result of extensive research to achieve the above object, the inventors have discovered that by making a nonwoven fabric with a high composition ratio of hydrophobic fibers and a low basis weight, the nonwoven fabric can be made bulky, thereby improving the water retention capacity and wet wiping properties, and also improving dewatering properties, resulting in a nonwoven fabric that is easy to spread after dewatering and has good handleability, and have thereby completed the present invention.

[0010] That is, the present invention can be configured in the following manner. [Aspect 1] A cleaning nonwoven fabric having an adhesive region of a binder and containing hydrophobic fibers, wherein the ratio of the hydrophobic fibers to the total fibers in the nonwoven fabric is 30% by weight or more (preferably 33 to 60% by weight, more preferably 38 to 50% by weight), and the basis weight is 45 g / m 2 or less (preferably 10 to 40 g / m 2 , more preferably 15 to 35 g / m 2 , and more preferably 20 to 30 g / m 2 ) is a nonwoven fabric for cleaning. [Aspect 2] The cleaning nonwoven fabric according to aspect 1, wherein the saturated water retention rate in a four-ply laminate is 900% or more (preferably 950% or more, more preferably 1000% or more). Aspect 3 A cleaning nonwoven fabric according to aspect 1 or 2, having an open area ratio of 16% or less (preferably 1 to 13%, more preferably 3 to 10%, and even more preferably 5 to 8%). Aspect 4 A cleaning nonwoven fabric according to any one of aspects 1 to 3, wherein at least one surface of the cleaning nonwoven fabric has a plurality of ridges or protrusions in which fibers are gathered in a ridge-like or protruding shape, and the average height of the plurality of ridges or protrusions is 100 μm or more (preferably 100 to 250 μm, more preferably 150 to 200 μm). Aspect 5 A cleaning nonwoven fabric according to any one of aspects 1 to 4, wherein the difference in saturated water retention between a four-ply state and a single-ply state is 120% or more (preferably 150% or more, more preferably 170% or more, and even more preferably 200% or more). Aspect 6 A cleaning nonwoven fabric according to any one of aspects 1 to 5, wherein the cleaning nonwoven fabric has a water retention rate after dehydration of 165% or less (preferably 160% or less, more preferably 150% or less). Aspect 7 In the cleaning nonwoven fabric according to any one of aspects 1 to 6, the binder has a deposition amount of 7.0 g / m 2 or less (preferably 0.5 to 6.0 g / m 2 , more preferably 1.0 to 5.0 g / m 2 , and more preferably 2.0 to 4.0 g / m 2 ) is a nonwoven fabric for cleaning. Aspect 8 The cleaning nonwoven fabric according to any one of aspects 1 to 7, having a density of 0.15 g / cm 3 or less (preferably 0.01 to 0.12 g / cm 3 , more preferably 0.03 to 0.09 g / cm 3 , and more preferably 0.05 to 0.08 g / cm 3 ) is a nonwoven fabric for cleaning. Aspect 9 A cleaning nonwoven fabric according to any one of aspects 1 to 8, wherein the hydrophobic fibers are at least one selected from the group consisting of polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyamide 6 fibers, and polyamide 66 fibers. Aspect 10 A cleaning nonwoven fabric according to any one of aspects 1 to 9, comprising hydrophilic fibers. Aspect 11 A wiper comprising the nonwoven cleaning fabric according to any one of aspects 1 to 10. [Effects of the Invention]

[0011] According to the cleaning nonwoven fabric of the present invention, the ratio of hydrophobic fibers to the total fibers in the nonwoven fabric is high within a specific range, thereby achieving good dewatering properties and making it easy to handle when used after squeezing out water. Furthermore, the inclusion of a large amount of hydrophobic fibers makes it possible to increase the bulk of the nonwoven fabric, thereby ensuring water retention even in a nonwoven fabric with a low basis weight, and providing excellent wet wiping properties in the water-retained state. [Brief explanation of the drawings]

[0012] The present invention will be more clearly understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings. The drawings are not necessarily drawn to scale, and are exaggerated to illustrate the principles of the present invention. However, the embodiments and drawings are for illustration and description purposes only and should not be used to define the scope of the present invention, which is defined by the appended claims.

[0013] [Figure 1] FIG. 2 is a schematic diagram showing a cross section of a cleaning nonwoven fabric to explain ridges. [Figure 2A] FIG. 2 is a diagram illustrating a state in which a test piece is suspended by a band clip in the measurement of saturated water retention. [Figure 2B] FIG. 2B is a side view of the test piece in the state shown in FIG. 2A. [Figure 3A] 3A is a plan view illustrating the process of folding a test piece folded in four so that a corner of the test piece is at the center in measuring the unfolding time. In FIG. 3A, one corner of the test piece is in a folded state. [Figure 3B] 3A and 3B are plan views illustrating the process of folding a test piece folded in four so that the corners are at the center of the test piece in measuring the unfolding time. In Fig. 3B, all four corners of the test piece are folded. [Figure 3C] FIG. 3C is a plan view showing a state in which a weighted acrylic plate is placed on the test piece in the state shown in FIG. 3B in measuring the development time. [Figure 3D] FIG. 3D is a side view of the test piece in the state shown in FIG. 3C. [Figure 3E]3E is a plan view showing the state of the test piece after the weighted acrylic plate was removed in the measurement of the unfolding time. In Fig. 3E, three corners of the test piece folded toward the center are unfolded beyond a right angle, and one corner is not unfolded beyond a right angle. [Figure 3F] FIG. 3B is a cross-sectional view taken along line AA′ of the test piece shown in FIG. 3E. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Nonwoven fabric for cleaning) The cleaning nonwoven fabric of the present invention (hereinafter sometimes simply referred to as nonwoven fabric) has a binder-bonded region. The binder-bonded region is a region where the binder is applied and where binder adhesion can be confirmed in a planar view, including the thickness direction. The nonwoven fabric may have a binder-bonded region over the entire nonwoven fabric. Alternatively, the nonwoven fabric may have a binder-bonded region partially and a non-bonded region. Here, the non-bonded region is a region where binder adhesion cannot be confirmed in a planar view, including the thickness direction. Note that if the nonwoven fabric has a mesh structure, the openings of the mesh structure are not included in the non-bonded region.

[0015] The nonwoven fabric of the present invention is useful as a cleaning nonwoven fabric and can be used, for example, as a wiper used for wiping off stains from precious metals such as jewels, tableware, tables, glass, electrical appliances, furniture, gas stoves, etc. Wipers using the nonwoven fabric of the present invention are excellent in handleability and water wiping ability, and are therefore useful for cleaning various stains, etc.

[0016] The nonwoven fabric may be a dry-laid nonwoven fabric, a wet-laid nonwoven fabric, or the like, but a dry-laid nonwoven fabric is preferred from the viewpoint of ensuring softness, and a spunlace nonwoven fabric formed by a hydroentanglement method is more preferred. The fiber length of the constituent fibers of the nonwoven fabric (e.g., hydrophobic fibers and / or hydrophilic fibers) may be, for example, about 20 to 70 mm, preferably about 25 to 65 mm, more preferably about 30 to 60 mm, and even more preferably about 35 to 55 mm.

[0017] To ensure softness, the nonwoven fabric may have constituent fibers (for example, hydrophobic fibers and / or hydrophilic fibers) with a fineness of, for example, about 1.0 to 3.5 dtex, preferably about 1.3 to 3 dtex, and more preferably about 1.5 to 2.5 dtex.

[0018] The nonwoven fabric contains hydrophobic fibers, and the ratio of the hydrophobic fibers to the total fibers in the nonwoven fabric is 30% by weight or more. In the present invention, it has been found that, as will be described later, even in a nonwoven fabric with a low basis weight, water retention and dewatering properties can be improved by including a specific amount of hydrophobic fibers.

[0019] By increasing the proportion of hydrophobic fibers, the nonwoven fabric can be made bulky, which ensures spaces between the fibers and enables water retention. Furthermore, a nonwoven fabric having high water retention and containing a large amount of hydrophobic fibers can fully release the retained water when wiping with water while retaining water, thereby increasing the area that can be wiped with water and providing excellent wet wiping properties.

[0020] Hydrophobic fibers have a higher repulsive force than hydrophilic fibers, which allow water to penetrate deep into the fibers, because water does not penetrate deep into the fibers or penetrates only slightly. Furthermore, hydrophobic fibers retain moisture between the fibers, allowing the moisture to be released when the nonwoven fabric is compressed and squeezed. Therefore, by increasing the composition ratio of hydrophobic fibers, sufficient moisture can be removed when the nonwoven fabric is squeezed, preventing the fibers from sticking together through the moisture. Furthermore, the repulsive force of the hydrophobic fibers can be utilized, making the nonwoven fabric easier to spread after squeezing. Thus, nonwoven fabrics with high dewatering properties and a high content of hydrophobic fibers spread easily after being soaked in water and then squeezed out by hand, resulting in excellent handling when wiping with water.

[0021] The ratio of hydrophobic fibers to all fibers in the nonwoven fabric may be, for example, 33% by weight or more, preferably 38% by weight or more. The upper limit of the ratio of hydrophobic fibers is not particularly limited, but may be, for example, 60% by weight or less, preferably 50% by weight or less.

[0022] In this specification, hydrophobic fibers refer to fibers with an official moisture regain of 5% by weight or less under standard conditions (20°C, 65% RH). This official moisture regain under standard conditions is calculated according to the method described in JIS L 1013. Examples of hydrophobic fibers include, but are not limited to, polyolefin fibers (e.g., polyethylene fibers, polypropylene fibers, etc.), polyester fibers (e.g., polyethylene terephthalate fibers, polybutylene terephthalate fibers, etc.), and polyamide fibers (e.g., polyamide 6 fibers, polyamide 66 fibers, etc.). Of these, polyester fibers are preferred because of their excellent resilience. One type of hydrophobic fiber may be used alone, or two or more types may be used in combination. Furthermore, the hydrophobic fibers are not particularly limited as long as they have the above-mentioned official moisture regain. For example, the fiber surface may be hydrophilized by adhering an oil or the like to the fiber surface.

[0023] The fibers constituting the nonwoven fabric may include various fibers other than hydrophobic fibers, such as hydrophilic fibers. The hydrophilic fibers are not particularly limited, and natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be used. These fibers may be used alone or in combination of two or more. Examples of hydrophilic natural fibers include natural cellulose fibers such as cotton, hemp, wool, and pulp. Examples of hydrophilic regenerated fibers include regenerated cellulose fibers such as rayon, lyocell such as Tencel (registered trademark), polynosic, and cupra. Examples of hydrophilic semi-synthetic fibers include semi-synthetic cellulose fibers such as acetate and triacetate. Suitable examples of hydrophilic synthetic fibers include synthetic fibers made of thermoplastic resins having hydrophilic functional groups such as hydroxyl groups, carboxyl groups, and sulfonic acid groups.

[0024] When hydrophilic fibers are included as fibers constituting the nonwoven fabric, the ratio of the hydrophilic fibers to the total fibers in the nonwoven fabric may be, for example, 70% by weight or less, preferably 65% ​​by weight or less. The lower limit of the ratio of the hydrophilic fibers is not particularly limited, but may be, for example, 30% by weight or more, preferably 40% by weight or more.

[0025] The nonwoven fabric has a basis weight of 45 g / m 2 The weight is, for example, 40 g / m 2 or less, preferably 35 g / m 2 or less, and more preferably 30 g / m 2 The lower limit of the basis weight is not particularly limited, but from the viewpoint of strength, it may be, for example, 10 g / m 2 or more, preferably 15 g / m 2 More preferably, 20 g / m 2 The basis weight is a value measured by the method described in the examples below, and includes the weight of the binder.

[0026] The nonwoven fabric has an apparent density (hereinafter sometimes simply referred to as density) of 0.15 g / cm 3 From the viewpoint of water retention, the density may be, for example, 0.12 g / cm 3 or less, preferably 0.09 g / cm 3 or less, and more preferably 0.08 g / cm 3 The lower limit of the density is not particularly limited, but from the viewpoint of strength, it is preferably 0.01 g / cm 3 or more, preferably 0.03 g / cm 3 More preferably, 0.05 g / cm 3 The density is a value measured by the method described in the examples below.

[0027] When using a low-basis-weight nonwoven fabric for wet wiping, it is common for it to be folded and stacked. However, from the viewpoint of further improving water retention between the layers of folded and stacked nonwoven fabric, the open area ratio may be 16% or less. In this specification, the open area ratio refers to the ratio of the area of ​​fiber-free portions (openings) to the total area of ​​the nonwoven fabric when viewed in plan. Openings include not only intentionally formed openings such as mesh holes in mesh-structured nonwoven fabrics, but also voids formed between the fibers that make up the nonwoven fabric in nonwoven fabrics or nonwoven fabric portions without a mesh structure. A small open area ratio of the nonwoven fabric allows moisture to be retained between the layers of the nonwoven fabric when folded and stacked, preventing it from escaping through the openings. From the viewpoint of further improving water retention, the open area ratio may be, for example, 13% or less, preferably 10% or less, and more preferably 8% or less. The lower limit of the open area ratio is not particularly limited, but may be, for example, 1% or more, preferably 3% or more, and more preferably 5% or more. The opening area ratio is a value measured by the method described in the examples below.

[0028] The nonwoven fabric may have an uneven structure on at least one surface. For example, the uneven structure may have, on at least one surface, a plurality of ridges, where fibers are gathered in a ridge-like shape, or a plurality of convex portions, where fibers are gathered in a convex shape. Here, a ridge is a raised portion on the surface of the nonwoven fabric that extends linearly in one direction, for example, along the machine direction (MD) or cross direction (CD), and a groove is formed between two ribs, extending parallel to the ribs. As an example, FIG. 1 shows a cross-sectional view of a nonwoven fabric 1 having ribs 2 and grooves 3. The convex portions are dot-like protrusions dispersed at a predetermined interval on the surface of the nonwoven fabric, and concave portions are formed around the convex portions. For example, the convex portions may have various shapes, such as a cone, a cylinder, a pyramid, or a prism. By providing ridges or convex portions on the surface of the nonwoven fabric, the nonwoven fabric becomes bulkier and its surface area increases. Furthermore, by providing ridges or protrusions on the surface of a nonwoven fabric, when the nonwoven fabric is folded and stacked, the ridges or protrusions can form spaces between the layers of the stacked nonwoven fabric, further improving the amount of water that can be retained between the layers of the stacked nonwoven fabric. This increases the amount of water retained on the surface of the nonwoven fabric, thereby improving the water retention of the nonwoven fabric.

[0029] The ridges or protrusions may be formed, for example, by a hydroentanglement process when the nonwoven fabric is produced by the spunlace method, or by using a net when collecting the fibers when the nonwoven fabric is produced by the meltblown method, or by post-processing by embossing.

[0030] The average height of the multiple ridges or protrusions may be 100 μm or more. For example, as shown in FIG. 1, the height h of the ridge 2 is measured as the distance from the bottom of the groove 3 to the top of the ridge 2. From the viewpoint of water retention, the average height may be, for example, 150 μm or more. The upper limit of the average height may be, for example, 250 μm or less, preferably 200 μm or less. The average height is a value measured by the method described in the examples below.

[0031] The nonwoven fabric may have a saturated water retention rate of 900% or more, preferably 950% or more, and more preferably 1000% or more when four sheets are stacked (assuming the state in which four sheets of nonwoven fabric are folded and stacked when normally used as a wiper). There is no particular upper limit to the saturated water retention rate when four sheets are stacked, but it may be, for example, 2000% or less.

[0032] The difference in saturated water retention between the four-ply nonwoven fabric and the single-layer nonwoven fabric (single layer of nonwoven fabric) may be 120% or more. From the viewpoint of water retention, the difference in saturated water retention between the four-ply nonwoven fabric and the single-layer nonwoven fabric may be, for example, 150% or more, preferably 180% or more, and more preferably 200% or more. The upper limit of the difference in saturated water retention between the four-ply nonwoven fabric and the single-layer nonwoven fabric is not particularly limited, but may be, for example, 400% or less. The difference in saturated water retention between the four-ply nonwoven fabric and the single-layer nonwoven fabric is an index of water retention between the layers of the folded and stacked nonwoven fabric. The difference in saturated water retention between the four-ply nonwoven fabric and the single-layer nonwoven fabric is a value measured by the method described in the Examples section below.

[0033] The binder contains at least an adhesive component, such as an acrylic resin (such as an acrylic acid ester copolymer resin), a polyurethane resin, a vinyl acetate copolymer resin, an epoxy resin, a styrene resin (such as a styrene-acrylic copolymer resin), or an olefin resin (such as polypropylene), and preferably contains at least one selected from the group consisting of an acrylic resin, a polyurethane resin, a styrene resin, and an olefin resin.

[0034] The binder may further contain at least one selected from the group consisting of a pigment, a penetrating agent, and a thickener, as necessary. Known or commonly used pigments, penetrating agents, and thickeners can be used depending on the purpose and composition. When the binder contains a pigment, a desired pattern can be formed on the nonwoven fabric of the present invention by partially coating the binder.

[0035] The nonwoven fabric has a binder attachment amount of 7.0 g / m2 per nonwoven fabric area, in order to maintain the repulsive force of the hydrophobic fiber and improve handling by making it easier to spread after squeezing out the water by hand. 2 From the viewpoint of maintaining the repulsive force of the hydrophobic fiber, the amount of binder attached may be, for example, 6.0 g / m 2 It may be less than 5.0 g / m 2 or less, and more preferably 4.0 g / m 2 The lower limit of the amount of binder attached is not particularly limited, but for example, it may be 0.5 g / m 2 or more, preferably 1.0 g / m 2 More preferably, 2.0 g / m 2 The amount of binder attached refers to the amount of attachment including not only adhesive components but also components such as pigments, penetrants, and thickeners, and is the dry amount of attachment.

[0036] The nonwoven fabric may have a water retention rate after dehydration of 165% or less. From the viewpoint of dehydration, the water retention rate after dehydration may be, for example, 160% or less, and preferably 150% or less. The lower limit of the water retention rate after dehydration is not particularly limited, but may be, for example, 50% or more. The water retention rate after dehydration is a value measured by the method described in the Examples below, and a lower value indicates better dehydration properties.

[0037] (Nonwoven fabric manufacturing method) The method for producing a nonwoven fabric includes, for example, a step of producing a raw nonwoven fabric in which the ratio of hydrophobic fibers to all fibers is 30% by weight or more, and a step of applying a binder to the raw nonwoven fabric, and the resulting nonwoven fabric has a basis weight of 45 g / m 2 The manufacturing method may be as follows.

[0038] The raw nonwoven fabric is prepared in the following manner. First, the above-mentioned fibers are formed into a web by carding or air-laid. Examples of the web shape include cross webs, random webs, semi-random webs, and parallel webs, which may be used alone or in combination. The ratio of hydrophobic fibers to the total fibers in the web may be 30% by weight or more, preferably 33% by weight or more, and more preferably 38% by weight or more, and preferably 60% by weight or less, and more preferably 50% by weight or less. In this case, it is preferable to adjust the basis weight according to the amount of binder applied in the subsequent binder application step.

[0039] Next, the fibers of the obtained web are bonded to each other to give it practical strength, thereby obtaining a raw nonwoven fabric. As a bonding method, a mechanical three-dimensional entanglement method such as hydroentanglement or needle punching can be used, but from the viewpoint of imparting softness to the nonwoven fabric and controlling the structure of the nonwoven fabric, it is preferable to use hydroentanglement, which involves entanglement by a hydroentanglement treatment.

[0040] In the hydroentanglement method, a high-pressure water jet is sprayed from a nozzle with fine holes onto a porous support on which a web is placed, and the energy of the water jet entangles and bonds the fibers.

[0041] The structure of the nonwoven fabric raw roll can be adjusted by adjusting the conditions for the hydroentanglement method. For example, the diameter of the nozzle used to spray the water stream may be approximately 0.05 to 0.20 mm, and, depending on the content of hydrophobic fibers in the nonwoven fabric raw roll, may be preferably 0.12 to 0.18 mm, more preferably 0.14 to 0.17 mm, from the viewpoint of forming ridges on at least one surface of the nonwoven fabric raw roll and reducing the open area ratio. Furthermore, the spacing (pitch) of the fine holes in the nozzle may be, for example, approximately 0.3 to 5.0 mm, and, from the viewpoint of adjusting the average height of the ridges, may be preferably 0.8 to 2.0 mm. The open area ratio of the resulting nonwoven fabric can be adjusted by adjusting the basis weight (fiber content) and fiber blending ratio of the web, the mesh size of the net used for hydroentanglement, the water pressure, etc. For example, because hydrophilic fibers such as rayon fibers are easily moved by water currents, increasing the blending ratio of hydrophobic fibers tends to reduce the open area ratio of the nonwoven fabric. Furthermore, by adjusting the open area ratio of the nonwoven fabric and adjusting the nozzle diameter used in the final high-pressure water jet treatment, structures such as ridges and protrusions can be formed on the surface of the nonwoven fabric.

[0042] By applying a binder to the obtained raw nonwoven fabric, an adhesive region of the binder can be formed. Examples of methods for applying the binder include a method of coating the binder on at least one surface of the raw nonwoven fabric or a dip-nip method. These methods may also be used in combination. The binder may be an emulsion in which the above-mentioned adhesive components and other optional components are dispersed in an aqueous solvent such as water, as necessary. When an emulsion is used, the viscosity of the binder can be appropriately determined by adjusting the solids concentration, etc., depending on the method for applying the binder and the amount applied.

[0043] When applying the binder, the binder may be applied to the entire surface of the nonwoven fabric roll or may be applied partially. Examples of application methods include printing, spraying, and foaming. Printing is preferred because it allows control of the binder application area. In the printing method, the nonwoven fabric roll is brought into contact with a roll to which a binder has been applied, thereby coating the binder on the surface of the nonwoven fabric roll in contact with the roll. By using a pattern roll as the roll in contact with the nonwoven fabric roll, it is possible to partially expose the binder to an adhesive area.

[0044] When the binder is dip-nipped, the dip-nip may be a process of immersing the raw nonwoven fabric in the binder and then squeezing it with, for example, a mangle. In this case, the binder can be permeated into the entire surface and interior of the raw nonwoven fabric.

[0045] After the binder is applied, the binder can be fixed to the applied area by drying. The drying method is not particularly limited, and examples thereof include a method in which the raw nonwoven fabric to which the binder has been applied is brought into contact with a heated roll.

[0046] After drying the binder, the binder strength can be increased by heat treatment. The heat treatment method is not particularly limited, and examples thereof include contacting the binder with a heated roll or exposing the binder to hot air. [Example]

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods. When measuring various physical properties, the measurement sample may be a portion taken out of the final product, for example, it may be taken out from a box or film package and measured. It may also be a portion cut out of a folded shape after being processed into a wiper and measured. In the case of a product made of multiple sheets, the sample may be taken from any position in the stack. In the case of a product processed into a roll, it may be unwound and measured, or it may be taken from anywhere from the surface of the roll close to the core.

[0048] [Metsuke] According to 6.2 of JIS L 1913 "General nonwoven fabric test method", the basis weight of the nonwoven fabric (g / m 2 ) was measured.

[0049] Thickness According to JIS L 1913 "General nonwoven fabric test method" 6.1, presser pressure: 12g / cm 2 The thickness of the nonwoven fabric was measured using a measuring instrument with a pressure plate diameter of 1.0 inch.

[0050] [Amount of binder attached] The filter paper (made of polypropylene) was dried completely, and the dry weight was measured as A (g). Next, the nonwoven fabric sample was cut into 15 cm squares, placed in a glass beaker, and immersed in concentrated sulfuric acid to dissolve the fibers in the nonwoven fabric in a 96% sulfuric acid solution (concentrated sulfuric acid), and the resulting mixture was filtered through the PP filter paper. Furthermore, the residue remaining in the glass beaker was completely washed into the filter paper with a 75% sulfuric acid solution. Thereafter, the filter paper was washed with running water so that no sulfuric acid remained, and the filter paper was dried completely with the filtrate still included, and the total dry weight was measured as B (g). The residue that did not dissolve in sulfuric acid and remained after filtration was considered to be the amount of binder attached to the fiber, and the amount of binder attached, C (g / m), was calculated using the following formula: 2 ) was calculated. C(g / m 2 )=(BA) / 15 / 15×10000 The amount of binder attached may be a value calculated from the manufacturing conditions if it can be calculated from the manufacturing conditions.

[0051] [Apparent density] The apparent density of the nonwoven fabric (g / cm) is calculated by dividing the basis weight by the thickness. 3 ) was calculated.

[0052] [Opening area ratio] A 10cm x 10cm test piece was cut from the nonwoven fabric and placed on a black stand. A 23x magnified image of the test piece surface was taken using a digital microscope DSX1000 (Olympus Corporation). The analysis settings were "Phase Red, Channel Red 100, Green 150, Blue 150." The areas of the test piece holes that appeared red were defined as openings, and their areas were measured. The ratio of the opening area to the total area of ​​the test piece was calculated as the opening area ratio.

[0053] [Height of ridge or convexity] Using a non-contact surface roughness and shape measuring instrument, the One-Shot 3D Measuring Macroscope VR-3000 (manufactured by Keyence Corporation), the ten-point average roughness was measured in accordance with JIS B0601:2001 (surface roughness measurement) under the following measurement conditions. Sample size: 15cm x 15cm Magnification: 120x Measurement range: 15.678 mm horizontally, 6 mm vertically, 61 lines Measurement: In the measurement under the above conditions, the roughness curve in the horizontal direction of the measurement range was measured 61 times along the vertical direction for the sample placed on the measuring instrument. The heights of the five highest peaks (Z p1 ~Z p5 ) and the average absolute value of the depths of the first five valleys (Z v1 ~Z v5 The ten-point mean roughness, calculated as the sum of the average values ​​of the absolute values ​​of the surface roughness, was measured, and the average value of 61 measurements was calculated as the ten-point mean roughness of one sample. Measurements were performed on both the front and back of the sample, and the side with the larger ten-point mean roughness value was used as the measurement surface of that sample. Measurements were also performed when the MD of the sample was the transverse direction and when the CD was the transverse direction, and the side with the larger ten-point mean roughness value was calculated as the ten-point mean roughness of that sample. Measurements were performed on three samples, and the average of these ten-point mean roughness values ​​was used as the height of the ridges or protrusions.

[0054] [Saturated water retention rate] The saturated water retention rates of the single-layer nonwoven fabric and the four-ply nonwoven fabric were determined as follows. A 5 cm square test specimen was prepared, and its dry weight (g) was measured using an electronic balance. The specimen was submerged in water for 30 seconds, then removed from the water. As shown in Figure 2A, a stainless steel clip 4 (Lion Office Equipment Co., Ltd., Janome Clip No. 53) was used to clamp one edge of the CD side of the specimen, with a clamping width of 2 mm. A string was passed through the clip's eye, and the specimen was suspended for 1 minute. As shown in Figure 2B, the specimen was clamped so that its edge did not extend beyond the clamping edge of the clip, preventing water from accumulating in the clip. The wet weight (g) of the specimen was then measured. The saturated water retention of the single-layer specimen was calculated using the following formula. The same test was repeated for five specimens, and the average value was used as the saturated water retention of the single-layer specimen. Saturated water retention rate = (wet weight - dry weight) / dry weight x 100 (%) Four 5cm square test pieces were prepared, and the dry weight (g) of the stacked test piece was measured using an electronic balance. The stacked test piece was submerged in water for 30 seconds, then pulled out of the water and hung by a clip for 1 minute, similar to the measurement of the single layer state. The wet weight (g) of the stacked test piece was measured. The saturated water retention of the four-ply stacked state was calculated using the above formula. The same test was repeated for five stacked test pieces, and the average value was used as the saturated water retention of the four-ply stacked state.

[0055] [Difference in saturated water retention rate] The difference in saturated water retention between the four-ply and single-layer conditions was calculated by subtracting the saturated water retention in the single-layer condition from the saturated water retention in the four-ply condition.

[0056] [Wipe area] Four test pieces measuring 20 cm long x 10 cm wide were prepared, and the dry weight (g) of the stacked test piece was measured using an electronic balance. 8 g of water was dropped onto the stacked test piece using a dropper, and the stacked test piece was placed in a zipper bag. A roller was used from outside the bag to distribute the moisture evenly. The stacked test piece was then left for one hour to allow the moisture to penetrate the entire stacked test piece. The stacked test piece was then removed from the zipper bag and placed on an electronic balance to adjust the moisture content to 5 g. The stacked test piece was folded in half lengthwise and wiped against a sheet measuring 40 cm long x 50 cm wide, placed on a laboratory bench. The sheet used was designed to visually indicate when water was being applied. Once the water from the stacked test piece had been applied to the entire section, the next sheet was wiped. The area wiped with water was evaluated based on the following criteria. ◎: Water was evenly applied to 13 or more sections. ○: Water was applied uniformly to 12 or more sections and less than 13 sections. △: Water was applied uniformly to 11 or more sections and less than 12 sections. ×: Water was uniformly applied to less than 10 sections.

[0057] [Water retention rate after dehydration] A test piece measuring 25 cm long x 13 cm wide was prepared, and the dry weight (g) of the test piece was measured using an electronic balance. The test piece was submerged in water for 30 seconds, then removed from the water and dehydrated using a test fabric dehydrator, Model No. VPM-1A (manufactured by Tsujii Senki Kogyo Co., Ltd., with a rubber roller made of silicone rubber with a rubber hardness of 90°), at a speed of 2 m / min and a pressure of 1.0 kgf / cm. 2 The test piece was squeezed with a sieve. The weight (g) of the test piece after dehydration was measured. The water retention rate after dehydration was calculated using the following formula. The same test was repeated for five test pieces, and the average value was used as the water retention rate after dehydration. Water retention rate after dehydration = (weight after dehydration - dry weight) / dry weight x 100 (%)

[0058] [Deployment Time] A test specimen measuring 30 cm long x 30 cm wide was prepared, and its dry weight (g) was measured using an electronic balance. The specimen, folded in quarters, was placed in a tray containing a thin layer of water and allowed to penetrate evenly. The specimen was removed from the tray and suspended using a stainless steel snake-eye clip. The specimen was then gently clamped between filter paper to remove excess water. The specimen was placed on an electronic balance and adjusted to a water retention of 200%. As shown in Figures 3A and 3B, the specimen was folded so that its four corners were centered. An acrylic plate 5 (22 g, 14 cm long x 12.5 cm wide) with a 50 g weight 6 attached to the center was placed on top of the folded specimen for 1 minute, as shown in Figures 3C and 3D. Approximately 50 seconds before removing the acrylic plate 5, a camera was started to capture the specimen. The acrylic plate 5 was then removed from the specimen, and the specimen was allowed to unfold naturally, as shown in Figure 3E. Filming was stopped after the movement of the test piece had stopped. Using the filmed footage, the time (seconds) until the folded portion unfolded at all four corners of the test piece folded toward the center, and the angle θ of the base of the folded portion when viewed horizontally, exceeded a right angle, was measured as the unfolding time. In the example shown in Figure 3F, the angle θ1 of the base of the folded portion on the left side exceeds a right angle, but the angle θ2 of the base of the folded portion on the right side does not exceed a right angle.

[0059] Example 1 A fiber web was produced by laminating webs spun using a semi-random card using 60% by mass of rayon fiber (Corona manufactured by Daiwabo Rayon Co., Ltd.) with a fineness of 1.7 dtex and a fiber length of 40 mm and 40% by mass of polyethylene terephthalate fiber (Tetoron (registered trademark) 471 manufactured by Toray Industries, Inc.) with a fineness of 1.6 dtex and a fiber length of 51 mm. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 2 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #76 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.15 mm and a pitch of 1.0 mm. The moisture content of the nonwoven fabric roll, the fibers of which had been entangled by the hydroentanglement treatment, was adjusted to 120% by mass, and a binder was applied using a gravure roll with a corrugated pattern with a pitch of 3.0 mm between adjacent diagonal corrugations. The binder used was an acrylic resin (acrylic emulsion) with a solids concentration of 30% and a viscosity adjusted to 100-150 mPa·s. The binder was applied to the nonwoven fabric roll at a rate of approximately 10 g / m 2 It was applied. Thereafter, drying and heat treatment were carried out using a cylinder dryer. The surface temperature of the drying treatment roll was set to 160°C, and the nonwoven fabric was repeatedly dried 10 times (5 times on each side) while alternately contacting the front and back of the nonwoven fabric with the roll. Next, the surface temperature of the heat treatment roll was set to 140°C, and the nonwoven fabric was repeatedly heat treated 20 times (10 times on each side) while alternately contacting the front and back of the nonwoven fabric. This series of processes was carried out at a speed of 60 m / min (final drying treatment step), and a nonwoven fabric having the configuration shown in Table 1 was produced. The nonwoven fabric of Example 1 had a ridge structure on one surface.

[0060] Example 2 A web was spun using 65% by mass of 1.7 dtex, 40 mm long rayon fiber ("Corona" manufactured by Daiwabo Rayon Co., Ltd.) and 35% by mass of 1.6 dtex, 51 mm long polyethylene terephthalate fiber ("Tetoron (registered trademark) 471" manufactured by Toray Industries, Inc.), and the resulting web was cross-wrapped using a parallel card. To adjust the basis weight, the web was stretched in the MD using a drafter. Semi-random carded webs of the same fiber composition were then laminated at a basis weight ratio of cross web:semi-random web of 65:35 to produce a fiber web. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 2 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #10 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.12 mm and a pitch of 0.6 mm. The nonwoven fabric raw material, the fibers of which have been entangled by the hydroentanglement treatment, is treated with a dip-nip treatment to apply a binder (acrylic emulsion) adjusted to a solids concentration of 9% at a rate of approximately 50 g / m 2 After that, a cylindrical dryer was used to set the surface temperature of the drying roll to 160°C, and the front and back of the nonwoven fabric were dried 10 times (five times on each side), and the binder was applied using a gravure roll with a corrugated pattern with a pitch of 7.0 mm between adjacent corrugations. The binder used was an acrylic resin (acrylic emulsion) with a solids concentration of 10% and a viscosity adjusted to 100-150 mPa·s. The binder was applied to the nonwoven fabric roll at a rate of approximately 20 g / m 2 It was applied. Thereafter, the nonwoven fabric was dried and heat-treated 20 times (10 times on each side) using a cylinder dryer at a surface temperature of 140°C. This series of processes was carried out at a speed of 30 m / min (final drying step) to produce a nonwoven fabric having the composition shown in Table 1.

[0061] Example 3 A web was spun using 70% by mass of rayon fiber (Corona manufactured by Daiwabo Rayon Co., Ltd.) with a fineness of 1.7 dtex and a fiber length of 40 mm and 30% by mass of polyethylene terephthalate fiber (Tetron® 471 manufactured by Toray Industries, Inc.) with a fineness of 1.6 dtex and a fiber length of 51 mm, and the resulting web was cross-wrapped using a cross wrapper. To adjust the basis weight, the web was stretched in the MD using a drafter. Semi-random carded webs made of the same fiber composition were then laminated so that the basis weight ratio of the cross web to the semi-random web was 65:35 to produce a fiber web. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 5 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 6 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #25 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.12 mm and a pitch of 0.6 mm. The moisture content of the nonwoven fabric roll, the fibers of which had been entangled by the hydroentanglement treatment, was adjusted to 120% by mass, and a binder was applied using a gravure roll with a corrugated pattern with a pitch of 7.0 mm between adjacent corrugations. The binder used was an acrylic emulsion with a solids concentration of 30% acrylic resin and a viscosity adjusted to 100-150 mPa·s. Approximately 20 g / m of binder was applied to the nonwoven fabric roll. 2 It was applied. The nonwoven fabric was then dried and heat-treated using a cylinder dryer. The surface temperature of the drying roll was set to 160°C, and the nonwoven fabric was dried 10 times (5 times on each side) by alternating between the front and back. The surface temperature of the heat-treatment roll was then set to 140°C, and the nonwoven fabric was heat-treated 20 times (10 times on each side) by alternating between the front and back. This series of processes was carried out at a speed of 30 m / min (final drying process), and a nonwoven fabric having the composition shown in Table 1 was produced.

[0062] Example 4 A web was spun using 60% by mass of 1.7 dtex, 40 mm long rayon fiber ("Corona" manufactured by Daiwabo Rayon Co., Ltd.) and 40% by mass of 1.6 dtex, 51 mm long polyethylene terephthalate fiber ("Tetoron (registered trademark) 471" manufactured by Toray Industries, Inc.), and the resulting web was cross-wrapped using a parallel card. To adjust the basis weight, the web was stretched in the MD using a drafter. Semi-random carded webs of the same fiber composition were then laminated at a basis weight ratio of cross web:semi-random web of 65:35 to produce a fiber web. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 2 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #76 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.12 mm and a pitch of 0.6 mm. The nonwoven fabric raw material, the fibers of which have been entangled by the hydroentanglement treatment, is treated with a dip-nip treatment to apply a binder (acrylic emulsion) adjusted to a solids concentration of 9% at a rate of approximately 50 g / m 2After that, a cylindrical dryer was used to set the surface temperature of the drying roll to 160°C, and the front and back of the nonwoven fabric were dried 10 times (five times on each side), and the binder was applied using a gravure roll with a corrugated pattern with a pitch of 3.0 mm between adjacent diagonal corrugations. The binder used was an acrylic resin (acrylic emulsion) with a solids concentration of 15% and a viscosity adjusted to 100-150 mPa·s. The binder was applied to the nonwoven fabric roll at a rate of approximately 10 g / m 2 It was applied. Thereafter, the nonwoven fabric was dried and heat-treated 20 times (10 times on each side) using a cylinder dryer at a surface temperature of 140°C. This series of processes was carried out at a speed of 35 m / min (final drying step) to produce a nonwoven fabric having the structure shown in Table 1. The nonwoven fabric of Example 4 had a ridge structure on one surface.

[0063] Example 5 A web was spun using 65% by mass of 1.7 dtex, 40 mm long rayon fiber ("Corona" manufactured by Daiwabo Rayon Co., Ltd.) and 35% by mass of 1.6 dtex, 51 mm long polyethylene terephthalate fiber ("Tetoron (registered trademark) 471" manufactured by Toray Industries, Inc.), and the resulting web was cross-wrapped using a parallel card. To adjust the basis weight, the web was stretched in the MD using a drafter. Semi-random carded webs of the same fiber composition were then laminated at a basis weight ratio of cross web:semi-random web of 65:35 to produce a fiber web. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 5 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 6 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #10 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.12 mm and a pitch of 0.6 mm. The moisture content of the nonwoven fabric roll, the fibers of which had been entangled by the hydroentanglement treatment, was adjusted to 120% by mass, and a binder was applied using a gravure roll with a corrugated pattern with a pitch of 6.0 mm between adjacent corrugations. The binder used was an acrylic emulsion with a solids concentration of 40% acrylic resin and a viscosity adjusted to 100-150 mPa·s. Approximately 20 g / m of binder was applied to the nonwoven fabric roll. 2 It was applied. The nonwoven fabric was then dried and heat-treated using a cylinder dryer. The surface temperature of the drying roll was set to 160°C, and the nonwoven fabric was dried 10 times (5 times on each side) by alternating between the front and back. The surface temperature of the heat-treatment roll was then set to 140°C, and the nonwoven fabric was heat-treated 20 times (10 times on each side) by alternating between the front and back. This series of processes was carried out at a speed of 30 m / min (final drying process), and a nonwoven fabric having the composition shown in Table 1 was produced.

[0064] (Comparative Example 1) A fiber web was produced by laminating webs spun using a semi-random card using 85% by mass of rayon fiber (Corona manufactured by Daiwabo Rayon Co., Ltd.) with a fineness of 1.7 dtex and a fiber length of 40 mm and 15% by mass of polyethylene terephthalate fiber (Tetoron (registered trademark) 471 manufactured by Toray Industries, Inc.) with a fineness of 1.6 dtex and a fiber length of 51 mm. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 4 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #25 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 4 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 1.0 mm, followed by a high-pressure water stream of 5 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The moisture content of the nonwoven fabric roll, the fibers of which had been entangled by the hydroentanglement treatment, was adjusted to 120% by mass, and a binder was applied using a gravure roll with a grid pattern having a pitch of 6.0 mm between adjacent grids. The binder used was an acrylic resin (acrylic emulsion) with a solids concentration of 40% and a viscosity adjusted to 100-150 mPa·s. Approximately 25 g / m of binder was applied to the nonwoven fabric roll. 2 It was applied. Thereafter, using a cylinder dryer, the surface temperature of the drying treatment roll was set to 160°C, and the nonwoven fabric was dried 10 times (5 times on each side) by alternating between the front and back sides. Next, the surface temperature of the heat treatment roll was set to 140°C, and the nonwoven fabric was heat-treated 20 times (10 times on each side) by alternating between the front and back sides. This series of processes was carried out at a speed of 40 m / min (final drying treatment step), and a nonwoven fabric having the composition shown in Table 1 was produced.

[0065] (Comparative Example 2) A fiber web was produced by laminating webs spun by semi-random carding using 100% by mass of rayon fiber (Corona, manufactured by Daiwabo Rayon Co., Ltd.) having a fineness of 1.7 dtex and a fiber length of 40 mm. The fiber web was placed on a metal punched drum (first drum) with a diameter of 0.40 mm and an opening ratio of 9.5%. While suction was applied, a water stream of 1 MPa was applied to the fiber web from a nozzle with a diameter of 0.08 mm and a pitch of 0.6 mm, followed by a water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a second drum. The fiber web was then subjected to a high-pressure water stream of 3 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm, followed by a high-pressure water stream of 4 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The fiber web was then turned over and placed on a #25 plain-weave polyester net conveyor. While suction was applied, the fiber web was subjected to a high-pressure water stream of 4 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 1.0 mm, followed by a high-pressure water stream of 5 MPa from a nozzle with a diameter of 0.1 mm and a pitch of 0.6 mm. The moisture content of the nonwoven fabric roll, the fibers of which had been entangled by the hydroentanglement treatment, was adjusted to 120% by mass, and a binder was applied using a gravure roll with a grid pattern having a pitch of 6.0 mm between adjacent grids. The binder used was an acrylic resin (acrylic emulsion) with a solids concentration of 40% and a viscosity adjusted to 100-150 mPa·s. Approximately 20 g / m of binder was applied to the nonwoven fabric roll. 2 It was applied. Thereafter, using a cylinder dryer, the surface temperature of the drying treatment roll was set to 160°C, and the nonwoven fabric was dried 10 times (5 times on each side) by alternating between the front and back sides. Next, the surface temperature of the heat treatment roll was set to 140°C, and the nonwoven fabric was heat-treated 20 times (10 times on each side) by alternating between the front and back sides. This series of processes was carried out at a speed of 40 m / min (final drying treatment step), and a nonwoven fabric having the composition shown in Table 1 was produced.

[0066] [Table 1]

[0067] As shown in Table 1, in Examples 1 to 5, the ratio of hydrophobic fibers to all fibers in the nonwoven fabric was high within a specific range, resulting in a large wiping area and a short unfolding time from a folded state, resulting in excellent wiping properties and ease of handling. In particular, Example 1 was evaluated as having the best wiping area and the shortest unfolding time of 1.5 seconds.

[0068] On the other hand, in Comparative Examples 1 and 2, the area that can be wiped with water is small and the time required to unfold from the folded state is long, so the wiping ability and handling ability are inferior compared to Examples 1 to 5. In particular, the wiping area of ​​Comparative Examples 1 and 2 were all evaluated as poor. Furthermore, in Comparative Example 1, the unfolding time was long at 17.0 seconds, and in Comparative Example 2, the test piece did not unfold beyond a right angle from the folded state, so handling ability was also poor. [Industrial Applicability]

[0069] As described above, the nonwoven fabric of the present invention has excellent handleability and water wiping ability, and is therefore useful as a cleaning nonwoven fabric, and can be suitably used, for example, as a wiper for wiping off stains on precious metals such as jewels, tableware, tables, glass, electrical appliances, furniture, gas stoves, etc.

[0070] While the preferred embodiments of the present invention have been described above with reference to the drawings, those skilled in the art will readily recognize various changes and modifications within the scope of the present invention upon reading the specification. Accordingly, such changes and modifications are to be interpreted as falling within the scope of the invention as defined by the claims. [Explanation of symbols]

[0071] 1...Nonwoven fabric for cleaning 2...ridge 3 Groove 4. Janome clip 5. Acrylic plate 6. Weight

Claims

1. A cleaning nonwoven fabric having an adhesive region of a binder and containing hydrophobic fibers, wherein the ratio of the hydrophobic fibers to the total fibers in the nonwoven fabric is 30% by weight or more, and the basis weight is 45 g / m 2 Below is a nonwoven cleaning fabric.

2. 2. The cleaning nonwoven fabric according to claim 1, wherein the saturated water retention rate when four sheets are stacked is 900% or more.

3. 3. The cleaning nonwoven fabric according to claim 2, wherein the open area ratio is 16% or less.

4. 4. The cleaning nonwoven fabric according to claim 3, wherein at least one surface of the cleaning nonwoven fabric has a plurality of ridges or protrusions in which fibers are gathered in a ridge-like or protruding shape, and the average height of the plurality of ridges or protrusions is 100 μm or more.

5. 2. The cleaning nonwoven fabric according to claim 1, wherein the difference in saturated water retention between the four-ply state and the single-ply state is 120% or more.

6. 2. The cleaning nonwoven fabric according to claim 1, which has a water retention rate after dehydration of 165% or less.

7. 7. The cleaning nonwoven fabric according to claim 6, wherein the binder has a coating weight of 7.0 g / m 2 Below is a nonwoven cleaning fabric.

8. 2. The cleaning nonwoven fabric according to claim 1, wherein the density is 0.15 g / cm ３ Below is a nonwoven cleaning fabric.

9. 2. The cleaning nonwoven fabric according to claim 1, wherein the hydrophobic fibers are at least one selected from the group consisting of polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyamide 6 fibers, and polyamide 66 fibers.

10. 10. The cleaning nonwoven fabric according to claim 1, comprising hydrophilic fibers.

11. A wiper comprising the nonwoven cleaning fabric according to any one of claims 1 to 10.

Images