Wiper and manufacturing method thereof

Abstract

The present invention provides a nonwoven fabric and wiper having excellent washing durability. The nonwoven fabric has a binder attachment site, and the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and when 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture content are 2 ) is 0.15 or more.

Description

[Technical field]

[0001] The present invention relates to a nonwoven fabric having excellent washing durability, a method for producing the same, and a wiper. [Background technology]

[0002] In recent years, the applications of nonwoven fabrics have expanded to include household goods, hygiene, medical, etc. Nonwoven fabrics are sometimes used as disposable products, but from economic and environmental perspectives, when they are used as wipers such as commercial dishcloths and industrial wipers, there is a demand for nonwoven fabrics that can be washed and reused.

[0003] For example, Patent Document 1 (JP 2008-115476 A) describes a fabric having a basis weight of 30 to 100 g / m2 formed from a fiber web containing at least rayon fiber and additionally containing synthetic fiber. 2 The nonwoven fabric is characterized in that an acrylic resin is applied twice to the front and back surfaces of the fiber web.

[0004] Patent Document 2 (JP 2008-213194 A) describes a nonwoven fabric sheet for cleaning, which has binder layers on the front and back surfaces of a nonwoven fabric sheet, and the nonwoven fabric sheet has an opening area of ​​2.0 to 4.0 mm 2 The nonwoven fabric sheet for wiping is characterized in that it has a through hole row pattern in which a plurality of through holes are arranged vertically and horizontally in a staggered manner, the distance between adjacent through holes in the through hole row pattern being 2.0 to 4.0 mm, the binder layer has two or more layers, at least one of which is formed over the entire front and back surfaces of the nonwoven fabric sheet, and the binder layer located in the uppermost front and back surface layers is composed of wavy lines arranged in parallel at equal intervals, forming a wavy pattern in a plan view.

[0005] Patent Document 3 (WO 2019 / 208160) discloses a nonwoven fabric having an adhesive region of a binder, in which a cut surface in the thickness direction randomly selected from the adhesive region is divided into three equal parts in the thickness direction, which are defined as an upper layer part, a lower layer part, and a middle layer part of the nonwoven fabric, and each part has 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 is expressed as the total number of fibers in the bundles in the upper layer part (Nu), the total number of fibers in the bundles in the lower layer part (Nb), and the total number of fibers in the bundles in the middle layer part (Nc), respectively, and the nonwoven fabric satisfies Nu / Nc>1.10 and Nb / Nc>1.10. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-115476 A [Patent Document 2] JP 2008-213194 A [Patent Document 3] International Publication No. 2019 / 208160 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Documents 1 and 2 state that the nonwoven fabric has washing durability, but the washing durability is merely evaluated based on the elongation of the fibers after one cycle in an electric bucket without a spin-drying function. In addition, in Patent Document 3, the washing durability is evaluated using a washing machine having a spin-drying function, but the washing durability is merely evaluated based on the fiber shape after five cycles.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a nonwoven fabric and a wiper which have significantly improved washing durability compared to conventional nonwoven fabrics and wipers. [Means for solving the problem]

[0009] As a result of intensive research by the inventors of the present invention to achieve the above object, during washing, laundry is subjected to stress during the washing and rinsing process under saturated moisture, and during the dehydration process in which moisture is released from a saturated moisture state by centrifugal action. Therefore, when evaluating nonwoven fabrics for their washing durability, official It was found that it is important to evaluate the nonwoven fabric when it is in a state where there is a certain amount of moisture, not when it is in a dry state when it is wet, and that the nonwoven fabric is subjected to particularly strong stress in the bias direction during the washing and rinsing process and the spin-drying process.Then, by focusing on the stress (bias stress) at 20% elongation in the bias direction at saturated moisture corresponding to the washing and rinsing process, and / or the bias stress of the nonwoven fabric at 300% wetness, which represents the state in which the nonwoven fabric is subjected to centrifugal action in the spin-drying process, it was found that the washing durability of the water-absorbent nonwoven fabric is dramatically improved when the stress at 20% elongation in the bias direction of the nonwoven fabric per unit basis weight, standardized by the basis weight of the nonwoven fabric, can be increased, that is, when the ratio (bias stress / basis weight) of the stress at 20% elongation in the bias direction at saturated moisture and / or 300% wetness of the nonwoven fabric to the basis weight of the nonwoven fabric can be increased, and thus the present invention was completed.

[0010] That is, the present invention can be configured in the following manner. [Aspect 1] A nonwoven fabric having a binder attachment portion, the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture 2 ) (bias stress / basis weight) is 0.15 or more (preferably 0.16 or more, more preferably 0.17 or more, and even more preferably 0.19 or more). [Aspect 2] In the nonwoven fabric according to the first aspect, the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture content are 2 ) ratio (bias stress / basis weight) of 0.35 or more. [Aspect 3] The nonwoven fabric according to aspect 1 or 2, wherein the ratio of the breaking strength (N / 5cm) in the machine direction (hereinafter, MD) to the breaking strength (N / 5cm) in the direction orthogonal to the MD (hereinafter, CD) at the standard moisture content of the nonwoven fabric (MD breaking strength / CD breaking strength) is 0.6 or more and less than 3.0 (preferably 0.6 to 2.9, and more preferably 0.6 to 1.5). Aspect 4 The nonwoven fabric according to any one of aspects 1 to 3, wherein the nonwoven fabric has a bias breaking strength of 25 N / 5cm or more (preferably 30 N / 5cm or more, more preferably 35 N / 5cm or more, and particularly preferably 45 N / 5cm or more) at the standard moisture content. Aspect 5 The nonwoven fabric according to any one of aspects 1 to 4, wherein the adhesion rate of the binder is 2 to 50 mass % (preferably 3 to 40 mass %, more preferably 4 to 30 mass %, and particularly preferably 5 to 20 mass %). Aspect 6 6. The nonwoven fabric according to any one of the first to fifth aspects, wherein the nonwoven fabric has a fiber arrangement structure derived from a cross web. Aspect 7 The nonwoven fabric according to any one of the first to sixth aspects, wherein the basis weight is 30 to 250 g / m 2 (Preferably 35 to 200 g / m 2 Approximately 40 to 150 g / m 2 ) nonwoven fabric. Aspect 8 The nonwoven fabric according to any one of aspects 1 to 7, wherein the ratio of the stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet to the average breaking strength (N / 5cm) in MD and CD when the nonwoven fabric is 300% wet (bias stress / average breaking strength) is 0.10 to 1.00 (preferably 0.13 to 0.95, more preferably 0.15 to 0.90, and even more preferably 0.18 to 0.90). Aspect 9 The nonwoven fabric according to any one of aspects 1 to 8, wherein when the nonwoven fabric (long side 30 cm × short side 5 cm) when 200% wet is placed on a horizontal surface with either the MD or CD of the nonwoven fabric being the long side, and one short side is lifted and laid over the other short side to form a curved shape of the nonwoven fabric, when observed from the side of the nonwoven fabric, the distance from the horizontal plane to the maximum height of the curved shape is 30 mm or less (preferably 25 mm or less, more preferably 22 mm or less) in the MD and / or 30 mm or less (preferably 25 mm or less, more preferably 20 mm or less) in the CD. Aspect 10 The nonwoven fabric according to any one of the first to ninth aspects, wherein the nonwoven fabric contains hydrophilic fibers in an amount of 50% by mass or more (preferably 60% by mass or more, and more preferably 70% by mass or more). Aspect 11 11. The nonwoven fabric of any one of the first to tenth embodiments, wherein the binder is present continuously on both surfaces of the nonwoven fabric. Aspect 12 12. The nonwoven fabric of any one of embodiments 1 to 11, wherein the nonwoven fabric has a plurality of apertures, the colored binder forms a continuous row of wavy patterns in the CD of the nonwoven fabric, and the wavy patterns are present in a plurality of rows that are approximately equally spaced from one another in the MD of the nonwoven fabric. Aspect 13 The nonwoven fabric according to any one of the first to twelfth aspects, wherein the water retention is 400% or more (preferably about 500% or more, and more preferably 600% or more). Aspect 14 A wiper, comprising the nonwoven fabric of any one of the preceding aspects. Aspect 15 A step of performing an entanglement treatment on the web having at least a cross-web structure by using a high-pressure water flow having a water pressure of 5 MPa or more to obtain a nonwoven fabric; applying a binder liquid to the nonwoven fabric by dip nip or coating; A method for producing a nonwoven fabric comprising the steps of: Aspect 16 A method for producing a nonwoven fabric according to embodiment 15, further comprising the step of drying the raw nonwoven fabric to which the binder liquid has been applied by alternately contacting the raw nonwoven fabric with a plurality of heated rolls using a cylinder dryer. Aspect 17 17. The method for producing a nonwoven fabric according to embodiment 15 or 16, wherein the temperature of the water jet in the entanglement treatment is 35° C. or higher (preferably 40° C. or higher).

[0011] Here, the bias direction means a direction that is 45° clockwise to the machine direction (hereinafter referred to as MD) and 45° counterclockwise to the direction perpendicular to the MD (hereinafter referred to as CD) at the standard moisture content of the nonwoven fabric.

[0012] "At saturation" refers to the state in which a nonwoven fabric is placed in a container, water is poured into the container, the nonwoven fabric is left completely immersed in water for 60 minutes, and then the nonwoven fabric is removed from the container without squeezing out the water.

[0013] "300% wet" refers to the state in which a nonwoven fabric is allowed to absorb three times its mass of water based on its official moisture content, and then left for 15 minutes until the moisture has penetrated evenly into the nonwoven fabric.

[0014] The term "standard moisture content" refers to the state in which the nonwoven fabric is placed under standard conditions (20±2°C, relative humidity 65±2%) and the mass of the nonwoven fabric becomes constant.

[0015] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly dictates otherwise. As used herein, the terms "and / or," "at least one," and "one or more" include any and all combinations of the associated listed items.

[0016] It should be noted that any combination of at least two elements disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims described in the claims is included in the present invention. Effect of the Invention

[0017] The present invention can dramatically improve the washing durability of the water-absorbent nonwoven fabric, and therefore the water-absorbent nonwoven fabric can be reused by washing it in a washing machine as usual, and can be suitably used as, for example, an industrial wiper or a dishcloth for business use that can be washed and reused. [Brief description of the drawings]

[0018] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention, which is defined by the appended claims.

[0019] [Figure 1] FIG. 13 is a schematic plan view for explaining a substantially linear attachment site. [Diagram 2] FIG. 11 is a schematic plan view for explaining a corrugated attachment portion. [Diagram 3] FIG. 2 is a schematic perspective view of a nonwoven fabric according to one embodiment for illustrating a method for measuring the maximum height of a curved shape at the approximate center portion formed by overlapping two halves of the nonwoven fabric. [Figure 4] FIG. 2 is a schematic diagram for explaining a step of drying a nonwoven fabric roll coated with a binder. [Diagram 5] FIG. 2 is a schematic plan view illustrating a method for measuring the length of a side of a nonwoven fabric sample before washing. [Figure 6] FIG. 2 is a schematic plan view illustrating a method for measuring the length of a side of a nonwoven fabric sample before washing. [Figure 7]FIG. 2 is a schematic plan view showing a length measuring plate used for measuring the dimensional change rate of a nonwoven fabric sample after washing. [Figure 8] FIG. 13 is a schematic plan view showing a measurement method in which a nonwoven fabric sample after 30 washes is placed on a measuring plate and the amount of shrinkage relative to the measuring plate is subtracted. [Figure 9] FIG. 13 is a schematic plan view showing a measurement method in which a nonwoven fabric sample after 30 washes is placed on a length measuring plate and the amount of stretch relative to the length measuring plate is added up. [Figure 10] 1 is a photograph of the nonwoven fabric obtained in Example 1 after washing. [Figure 11] 1 is a photograph of the nonwoven fabric obtained in Comparative Example 3 after washing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The nonwoven fabric of the present invention is a water-absorbent nonwoven fabric having an adhesive surface formed by a binder, and is characterized by a bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, and a basis weight (g / m2) of the nonwoven fabric at the standard moisture content. 2 ) is 0.15 or more. The characteristics of the nonwoven fabric are explained below.

[0021] The nonwoven fabric of one embodiment has an adhesion site of a binder (glue or adhesive agent). Here, the adhesion site of the binder means a site where the binder is applied to the constituent fibers of the nonwoven fabric, and usually means a part where the binder attached to the fibers can be confirmed when the surface of the nonwoven fabric is visually observed. The nonwoven fabric of the present invention may partially have an adhesion site of the binder and a non-adhesive site. Here, the non-adhesive site is a part where the binder adhesion cannot be confirmed when the surface of the nonwoven fabric is visually observed. In addition, when the nonwoven fabric has a mesh structure, the openings due to the mesh structure are not included in the non-adhesive site.

[0022] Here, the adhesion of the binder to the fibers can be judged by the colored binder if the binder is colored, and can be judged by dyeing the binder using a dyeing method if the binder is transparent.

[0023] In one embodiment of the nonwoven fabric, the binder is attached to at least one surface of the nonwoven fabric, preferably on both the front and back surfaces of the nonwoven fabric, continuously from one end to the other end. attitude In the case where the binder has an attachment site continuously from one end to the other end, for example, the binder may form a planar attachment site without interruption from one end to the other end in the MD or CD of the nonwoven fabric, or may form a linear attachment site. In the case where the binder has an attachment site continuously from one end to the other end on at least one surface of the nonwoven fabric, attitude In this case, the constituent fibers of the nonwoven fabric can be efficiently bound by the binder.

[0024] The linear attachment sites may have various shapes depending on the width of the lines. The linear attachment sites may be in a shape where the lines do not intersect with each other, or in a shape where the lines intersect with each other at least in part. Such shapes may be striped (for example, stripes with straight lines or curved lines), lattice-like, etc.

[0025] In addition, when the lines intersect at least in part, it is possible to focus on a specific line from the perspective of shortening the distance from one end to the other end, and to grasp the shape of the linear attachment site for that line, in which case the line may share an intersection with other lines.

[0026] For example, schematic diagrams for explaining linear attachment sites are shown in Fig. 1 and Fig. 2. As shown in Fig. 1, for example, for a linear attachment site arbitrarily selected on at least one surface of a nonwoven fabric, the ratio (L1 / L2) of the distance L1 between the top and bottom of the line to the width L2 of the line may be, for example, 1 or more, preferably 1.5 or more, and may be, for example, 10 or less, preferably 8 or less. From the viewpoint of improving the fixation of the fiber, L1 / L2 is preferably 1.5 or more. Here, L1 represents the distance between the top and bottom measured within a range of 15 cm from one end of the linear attachment site, and L2 represents the average width of the line measured repeatedly 5 times every 2 cm within that range. The width of the line represents the width of the line in a direction perpendicular to the longitudinal direction of the line.

[0027] For example, as shown in FIG. 1, when the ratio (L1 / L2) of the distance L1 between the top and bottom of the line to the width L2 of the line is greater than or equal to 1 and less than 1.5, the linear attachment site can be regarded as being approximately linear, including a straight line of uniform width (L1 / L2=1).

[0028] On the other hand, when the ratio (L1 / L2) of the distance L1 between the top and bottom of the line to the line width L2 is 1.5 or more, as shown in Figure 2, the linear attachment site may form a wavy attachment site. The wavy shape may have various shapes such as a sine wave, a rectangular wave, a triangular wave, a sawtooth wave, etc., and may be preferably a sine wave.

[0029] The linear attachment sites may form a plurality of rows, preferably the plurality of rows being evenly spaced from one another.

[0030] Preferably, in the CD, a plurality of linear attachment sites are formed in a plurality of rows without interruption from one end to the other end, and in the MD, the plurality of rows may be present at approximately equal intervals from each other.

[0031] For example, the distance (pitch) between the rows may be, for example, 2 to 10 mm, and preferably 3 to 8 mm. Here, the pitch means the distance from the top of one row to the top of the adjacent row, and is indicated by X in FIG. 2, for example.

[0032] The weight per unit area of ​​the nonwoven fabric of one embodiment is, for example, 30 to 250 g / m from the viewpoint of strength. 2 and preferably 35 to 200 g / m 2 Approximately 40 to 150 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.

[0033] The thickness of the nonwoven fabric of one embodiment can be appropriately determined depending on the application, and is not particularly limited, but from the viewpoint of softness, the thickness may be, for example, about 0.1 to 2.0 mm, preferably about 0.2 to 1.5 mm, and more preferably about 0.3 to 1.0 mm. The thickness is a value measured by the method described in the examples described later.

[0034] From the viewpoint of water absorption, the nonwoven fabric of one embodiment may have a water retention rate of, for example, 400% or more, preferably about 500% or more, and more preferably 600% or more. The upper limit is not particularly limited, but may be about 900%. The water retention rate is a value measured by the method described in the examples below.

[0035] [Characteristics of nonwoven fabric when wet] By evaluating a nonwoven fabric based on its wet characteristics, it is possible to effectively evaluate the washing durability of the nonwoven fabric. In one embodiment of the nonwoven fabric, from the viewpoint of enhancing durability against stress applied during washing, the stress (bias stress) at 20% elongation in the bias direction per unit basis weight, standardized by the basis weight of the nonwoven fabric, is within a predetermined range in a wet nonwoven fabric. For example, the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, and the basis weight (g / m 2 The ratio (bias stress / basis weight) to the nonwoven fabric is 0.15 or more, preferably 0.16 or more, more preferably 0.17 or more, even more preferably 0.19 or more, and particularly preferably 0.35 or more. The upper limit of the ratio is not particularly limited, but from the viewpoint of the softness of the nonwoven fabric, it may be, for example, 0.90 or less, and preferably 0.80 or less.

[0036] When the nonwoven fabric of one embodiment is saturated with moisture and / or 300% wet, the bias stress at 20% elongation in the bias direction may be, for example, 7 N / 5 cm or more, preferably 10 N / 5 cm or more, more preferably 15 N / 5 cm or more, and particularly preferably 20 N / 5 cm or more. There is no particular upper limit, but it may be about 100 N / 5 cm. The bias stress at 20% elongation is a value measured by the method described in the Examples below.

[0037] In one embodiment of the nonwoven fabric, the unit weight (g / m2) is calculated when saturated with water and / or 300% wet. 2 The MD stress (N / 5 cm) at 20% elongation in the MD per unit length (N / 5 cm) may be, for example, 0.40 or more, preferably 0.60 or more, and more preferably 0.70 or more. The upper limit of the ratio may be, for example, 1.0 or less.

[0038] In one embodiment of the nonwoven fabric, the unit weight (g / m2) is calculated when saturated with water and / or 300% wet. 2 The CD stress (N / 5 cm) at 20% elongation in the CD per unit length (N / 5 cm) may be, for example, 0.10 or more, preferably 0.13 or more, and more preferably 0.15 or more. The upper limit of the ratio may be, for example, 0.50 or less.

[0039] In addition, the ratio of the stress (N / 5cm) at 20% elongation in the bias direction of one embodiment of the nonwoven fabric when saturated with moisture and / or 300% wet to the average breaking strength (N / 5cm) in the MD and CD of the nonwoven fabric when 300% wet (bias stress / average breaking strength) may be, from the viewpoint of further improving washing durability, for example, 0.10 to 1.00, preferably 0.13 to 0.95, more preferably 0.15 to 0.90, and even more preferably 0.18 to 0.90.

[0040] One embodiment of the nonwoven fabric has excellent flexibility when wet. For example, when a nonwoven fabric (when 200% wet) with a long side of 30 cm and a short side of 5 cm is placed on a horizontal surface with the MD or CD of the nonwoven fabric as the long side, and the nonwoven fabric is folded in half, the curved shape of the approximately central part of the nonwoven fabric that is produced when the nonwoven fabric is folded in half, i.e., the curved shape of the nonwoven fabric formed by lifting one short side and folding it over the other short side, is observed from the side of the nonwoven fabric. The distance from the horizontal plane to the maximum height of the curved shape may be, for example, 30 mm or less, preferably 25 mm or less, and more preferably 22 mm or less in the MD, and / or 30 mm or less, preferably 25 mm or less, and more preferably 20 mm or less in the CD.

[0041] Specifically, a schematic perspective view of one embodiment of a nonwoven fabric in FIG. 3 will be used for explanation. The nonwoven fabric in FIG. 3 has a long side in MD and a short side in CD. The nonwoven fabric has linear attachment sites formed in multiple rows in MD. The nonwoven fabric is made 200% wet, and then spread out on a horizontal surface and left to stand. Next, one short side is lifted and placed over the other short side without moving the other short side, forming a natural curve centered on approximately the center of the long side. The maximum height of the curve formed by the nonwoven fabric from the horizontal surface can be measured to determine the degree of softness of the nonwoven fabric when wet. Nonwoven fabrics will exhibit a certain maximum height depending on the construction of the nonwoven fabric, but the accuracy of the maximum height indicator can be improved by measuring the maximum height five times on samples cut from the same nonwoven fabric.

[0042] [Characteristics of nonwoven fabric at standard moisture content] The MD breaking strength of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 38 N / 5 cm or more, preferably 40 N / 5 cm or more, more preferably 45 N / 5 cm or more, and particularly preferably 50 N / 5 cm or more. The upper limit is not particularly limited, but may be about 250 N / 5 cm. The MD breaking strength is a value measured by the method described in the examples below.

[0043] The CD breaking strength of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 10 N / 5 cm or more, preferably 15 N / 5 cm or more, and more preferably 20 N / 5 cm or more. The upper limit is not particularly limited, but may be about 320 N / 5 cm. The CD breaking strength is a value measured by the method described in the examples below.

[0044] The average breaking strength of the nonwoven fabric of one embodiment at the standard moisture content is the average value of the MD breaking strength and the CD breaking strength, and may be, for example, 25 N / 5 cm or more, preferably 30 N / 5 cm or more, more preferably 35 N / 5 cm or more, and particularly preferably 45 N / 5 cm or more. The upper limit is not particularly limited, but may be about 250 N / 5 cm.

[0045] In the case of nonwoven fabrics, the ratio of the MD breaking strength (N / 5cm) to the CD breaking strength (N / 5cm) at the standard moisture content of the nonwoven fabric, which is an index showing the orientation of the fibers in the nonwoven fabric, may be, for example, 0.6 or more and less than 3.0, preferably 0.6 to 2.9, and more preferably 0.6 to 1.5, from the viewpoint of suppressing deformation due to stress applied during washing.

[0046] The breaking strength in the bias direction of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 25 N / 5 cm or more, preferably 30 N / 5 cm or more, more preferably 35 N / 5 cm or more, and particularly preferably 45 N / 5 cm or more. The upper limit is not particularly limited, but may be about 300 N / 5 cm.

[0047] The stress at 20% elongation in MD of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 40 N / 5 cm or more, preferably 50 N / 5 cm or more, and more preferably 60 N / 5 cm or more. The upper limit is not particularly limited, but may be about 200 N / 5 cm. The stress at 20% elongation in MD is a value measured by the method described in the Examples below.

[0048] The stress at 20% elongation in CD of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 10 N / 5 cm or more, preferably 13 N / 5 cm or more, and more preferably 15 N / 5 cm or more. The upper limit is not particularly limited, but may be about 100 N / 5 cm. The stress at 20% elongation in CD is a value measured by the method described in the Examples below.

[0049] The stress at 20% elongation in the bias direction of the nonwoven fabric of one embodiment at the standard moisture content may be, for example, 15 N / 5 cm or more, preferably 20 N / 5 cm or more, and more preferably 25 N / 5 cm or more. The upper limit is not particularly limited, but may be about 150 N / 5 cm. The stress at 20% elongation in the bias direction is a value measured by the method described in the examples below.

[0050] In addition, the ratio of the stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric of one embodiment at the standard moisture content to the average breaking strength (N / 5cm) in MD and CD at the standard moisture content of the nonwoven fabric (bias stress / average breaking strength) may be, for example, 0.30 or more, preferably 0.35 or more, and more preferably 0.37 or more. The upper limit is not particularly limited, but may be 2.00.

[0051] The MD deformation rate of the nonwoven fabric after the nonwoven fabric is washed 30 times in succession may be, for example, 90 to 110%, preferably 93 to 105%. The MD deformation rate of the nonwoven fabric is a value measured by the method described in the examples described later.

[0052] After the nonwoven fabric is washed 30 times in succession, the CD deformation rate of the nonwoven fabric is, for example, 、9It may be from 0 to 110%, and preferably from 93 to 105%. The CD deformation rate of the nonwoven fabric is a value measured by the method described in the examples below.

[0053] In one embodiment of the nonwoven fabric, for example, the MD wicking length after absorbing water for 1 minute, which is an index of water absorbency, may be, for example, 40 mm or more, preferably 45 mm or more, and more preferably 50 mm or more. The upper limit of the MD wicking length is not particularly limited, but may be, for example, 80 mm. The MD wicking length is a value measured by the method described in the Examples below.

[0054] In one embodiment of the nonwoven fabric, the CD wicking length after absorbing water for 1 minute, which is an index of water absorbency, may be, for example, 40 mm or more, preferably 45 mm or more, and more preferably 50 mm or more. The upper limit of the CD wicking length is not particularly limited, but may be, for example, 80 mm. The CD wicking length is a value measured by the method described in the Examples below.

[0055] [Nonwoven fabric constituent fibers] The fibers constituting the nonwoven fabric are not particularly limited as long as the nonwoven fabric exhibits a predetermined water absorbency, but may contain hydrophilic fibers in order to improve water absorbency. The hydrophilic fibers are not particularly limited, but natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be used. The hydrophilic fibers may be fibers that have been given hydrophilicity by post-processing. The hydrophilic fibers may be used alone or in combination of two or more types. 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. Examples of hydrophilic synthetic fibers include synthetic fibers composed of thermoplastic resins having hydrophilic functional groups such as hydroxyl groups, carboxyl groups, and sulfonic acid groups, and / or hydrophilic bonds such as amide bonds. Among these, preferred hydrophilic fibers may be cellulose fibers such as natural cellulose fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers. More preferred are rayon fibers (e.g., viscose rayon) and solvent-spun cellulose fibers (e.g., Lyocell such as Tencel) among regenerated cellulose fibers.

[0056] In order to ensure sufficient absorbency and water retention, the ratio of hydrophilic fibers (particularly hydrophilic fibers as main fibers) among the fibers constituting the nonwoven fabric may be, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. There is no particular upper limit to the ratio of hydrophilic fibers, but it may be, for example, 100% by mass or less.

[0057] The fibers constituting the nonwoven fabric may contain various synthetic fibers or natural fibers other than hydrophilic fibers. Examples of the synthetic fibers other than hydrophilic fibers include polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyester fibers such as polyethylene terephthalate fibers, polybutylene terephthalate fibers, and polylactic acid fibers, and composite fibers whose outer skin is made of a hydrophobic resin.

[0058] In addition to the main fibers, the nonwoven fabric may contain binder fibers capable of fusing the fibers in the nonwoven fabric together by thermal or chemical fusing. A preferred binder fiber is a fiber whose outer skin contains a resin component with a lower melting point than the main fibers. The binder fiber may be a non-composite fiber or a composite fiber. The composite fiber may be, for example, a composite fiber having a core-sheath structure with a low melting point resin as the sheath component and a high melting point resin as the core component. The low melting point resin and the high melting point resin may be appropriately selected according to the melting points of the fiber-forming resins described above in the synthetic fibers, and preferred combinations include polyolefin resins such as polyethylene and polypropylene as low melting point resins and polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid as high melting point resins. Even if binder fibers are contained, the binder fibers merely form point bonds between the fibers and are not included in the binder attachment sites in the nonwoven fabric.

[0059] From the viewpoint of improving the flexibility of the nonwoven fabric, the proportion of binder fibers among the fibers constituting the nonwoven fabric may be, for example, 30 mass % or less, preferably 20 mass % or less, and more preferably 10 mass % or less.

[0060] The fiber length of the constituent fibers of the nonwoven fabric (for example, main fibers, binder 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.

[0061] In order to ensure softness, the constituent fibers of the nonwoven fabric (for example, main fibers, binder fibers) may have 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.

[0062] [binder] 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, or a styrene resin (such as a styrene-acrylic copolymer resin), and preferably contains at least one selected from an acrylic resin, a polyurethane resin, and a styrene resin.

[0063] The binder may further contain at least one selected from the group consisting of a pigment, a penetrating agent, and a thickener, as necessary. The pigment, penetrating agent, and thickener may be publicly known or commonly used, depending on the purpose and configuration. When the binder contains a pigment, the binder can be partially coated to impart a desired pattern to the nonwoven fabric of the present invention. As described above, the smaller the ratio of the exposed area of ​​the binder exposed on the front and back surfaces is, the more uniform the pattern on the front and back surfaces of the nonwoven fabric can be obtained, and the more excellent the design can be.

[0064] In one embodiment of the nonwoven fabric, from the viewpoint of achieving both the softness of the nonwoven fabric and the binding ability of the fibers in the nonwoven fabric, the binder adhesion rate may be, for example, 2 to 50 mass%, preferably 3 to 40 mass%, more preferably 4 to 30 mass%, and particularly preferably 5 to 20 mass%. Here, the binder adhesion rate is a value measured by the method described in the examples described later.

[0065] Such nonwoven fabrics have excellent washing durability and can be easily washed using a washing machine, and even if the washing machine is used repeatedly, the durability of the nonwoven fabric is excellent, so that the nonwoven fabrics are useful as wipers for business use, industrial use, etc. Furthermore, the nonwoven fabrics can be easily washed using a washing machine in an ordinary household, and as household wipers, the nonwoven fabrics can reduce the time spent on daily housework.

[0066] (Nonwoven fabric manufacturing method) The method for producing the nonwoven fabric of the present invention includes the steps of: subjecting a web having at least a cross-web structure to an entanglement treatment using a high-pressure water flow having a water pressure of 5 MPa or more to obtain a nonwoven fabric; and applying a binder liquid to the raw nonwoven fabric by dip nip or coating.

[0067] [Nonwoven fabric roll] The nonwoven fabric raw roll is prepared by the following method. First, a web is formed from predetermined fibers by carding or air-laid method. From the viewpoint of increasing the bias stress at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, the web has at least a cross-web structure, and such a structure can be formed by including a cross web. The cross web is a web formed so that the fibers are oriented approximately in the CD of the nonwoven fabric. Furthermore, the cross web may be combined with a random card, semi-random card, or parallel card web as necessary.

[0068] The proportion of the cross web may be, for example, 30% by mass or more, preferably 45% by mass or more, and more preferably 60% by mass or more, based on the entire web. The upper limit of the proportion of the cross web is not particularly limited, but may be, for example, 95% by mass from the viewpoint of processability.

[0069] For example, the ratio of the cross web to the semi-random web, expressed as the mass ratio of cross web / semi-random web, may be 30 / 70 to 95 / 5, preferably 45 / 55 to 90 / 10, and more preferably 60 / 40 to 90 / 10.

[0070] Next, the fibers of the obtained web are bonded to each other to give a practical strength to obtain a nonwoven fabric raw material. As a bonding method, the fibers can be three-dimensionally entangled by a hydroentanglement method.

[0071] In the hydroentanglement method, a high-pressure water stream is jet-sprayed from a nozzle with fine holes onto a porous support on which a web is placed. The water stream penetrates the web and is reflected off a steel plate, and the resulting energy entangles and bonds the fibers.

[0072] In the entanglement treatment, the cross web is subjected to entanglement treatment with a high-pressure water stream having a water pressure of 5 MPa or more, and such a high-pressure water stream can make the entanglement between the fibers denser. The high-pressure water stream may be applied multiple times while increasing the pressure stepwise, and for example, the difference in pressure between the first high-pressure water stream and the final high-pressure water stream may be 0 to 5 MPa, and preferably 0 to 4 MPa.

[0073] The temperature of the water stream during the entanglement treatment may be, for example, 15° C. or higher, preferably 25° C. or higher, more preferably 35° C. or higher, and particularly preferably 40° C. or higher. The upper limit of the water stream temperature can be appropriately set depending on the type of fibers constituting the web, and may be, for example, 80° C. or lower.

[0074] A plurality of porous supports may be used, for example, by passing the nonwoven fabric through a first porous support to cause intertwining of the fibers having a three-dimensional shape, and then passing the nonwoven fabric through a second porous support to give the nonwoven fabric a desired mesh structure, in which case the second porous support may have a pattern shape corresponding to the desired mesh structure. Prior to the high pressure water jet treatment, a preliminary entanglement treatment may be performed with a water jet having a water pressure of less than 5 MPa. The water jet for the preliminary entanglement treatment is preferably 0.5 to 4 MPa, more preferably 0.8 to 3.5 MPa.

[0075] In order to adjust the binder distribution to a specific value, the weight of the nonwoven fabric is, for example, 10 g / m 2 More than 100g / m 2 It may be less than 20 to 95 g / m 2 Approximately 30 to 90 g / m 2 It may be to some extent.

[0076] (Binder application process) The nonwoven fabric raw roll (hereinafter sometimes simply referred to as raw roll) is subjected to a step of applying a binder liquid by dip nip or coating. The binder liquid may be used as 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 used as an emulsion, the viscosity of the binder can be appropriately determined by adjusting the solid content concentration, etc., depending on the method of applying the binder and the amount of application. For example, the solid content concentration can be selected from the range of 0.2% by mass to 60% by mass, and the viscosity can be selected from the range of 1 to 500 mPa·s.

[0077] In the case of coating, the binder liquid may be applied to the entire surface of the raw sheet or may be applied partially. Examples of the coating method include a printing method, a spraying method, a foaming method, etc., but the printing method is preferred from the viewpoint of being able to control the coating area of ​​the binder.

[0078] In the printing method, the raw material is brought into contact with a roll to which a binder has been applied, so that the binder is applied to the surface of the raw material in contact with the roll. When printing, the binder is applied according to the pattern to be formed on the surface of the final product. Such a pattern is not particularly limited, but may be any of a variety of linear shapes as defined by the L1 / L2 described above.

[0079] The moisture content of the raw roll before coating may be adjusted to 50 to 450% by mass. By adjusting the raw roll to a specific moisture content before coating, the binder coated on the surface can be dispersed in the water held by the raw roll, and can be sufficiently penetrated into the inside of the raw roll. The moisture content of the raw roll before coating may be preferably 80 to 350%, more preferably 100 to 200%.

[0080] In the case of the dip nip method, the raw material is immersed in the binder liquid, and then, in order to remove the excess binder liquid, the raw material is squeezed, for example, with a mangle, etc. In this case, the binder can be permeated into the entire surface and inside of the raw material.

[0081] When dip nipping is performed, the nonwoven fabric raw roll before immersion in the binder may be dried and used in a state of 0% moisture content. The binder content of the nonwoven fabric raw roll after dip nipping may be adjusted to 50 to 800% by mass, more preferably 80 to 500%, and even more preferably 100 to 250%. The binder content of the raw roll may be adjusted, for example, by the transport speed or nip pressure when immersing the raw roll.

[0082] (drying process) Preferably, in the drying step, the front and back sides of the raw roll to which the binder liquid has been applied are alternately brought into contact with different heated rolls using a cylinder-type dryer to dry. As a result, the binder can be moved to the surface side of the raw roll in contact with the heated roll as moisture moves inside the raw roll. Specifically, as moisture evaporates on the surface of the raw roll in contact with the heated roll, moisture diffuses to the part of the raw roll that is deficient in moisture due to evaporation, and solids such as adhesive components dispersed in water move to the surface in contact with the heated roll along with the diffusion. Next, the raw roll comes into contact with the next heated roll, and the surface of the raw roll in contact with the next heated roll is heated relatively more, so the direction of moisture diffusion is reversed, and as moisture moves to the heated roll side, solids such as adhesive components move to the surface in contact with the heated roll. Therefore, even if the binder is applied only to one surface, it is possible to attach it to the surface on the opposite side. Then, by alternately contacting the front and back sides with different heated rolls and drying them, solid components such as adhesive components can be passed through the inside and transferred to the front and back sides, and after drying, the binder can be distributed in a greater amount on the surface of the nonwoven fabric than inside the nonwoven fabric.

[0083] Also, for example, as shown in FIG. 4, when the binder is applied only to one surface of the raw nonwoven fabric 10, the non-coated surface 12, which is the surface opposite to the coated surface 11, is first brought into contact with the first heated roll 30 in the drying process, and then the coated surface 11 is brought into contact with the second heated roll 31. Furthermore, the non-coated surface 12 is brought into contact with the third heated roll 32, and then the coated surface 11 is brought into contact with the fourth heated roll 33. If necessary, the non-coated surface 12 and the coated surface 11 may be alternately brought into contact with another heated roll for drying. In the drying process, by first bringing the non-coated surface into contact with the heated roll, the solid content in the binder, which is more distributed on the coated surface side, can be moved to the non-coated surface side while the raw fabric contains a lot of moisture, which is a medium for the movement of the solid content in the binder. Therefore, the uniformity of the distribution amount of the binder on both surfaces of the obtained nonwoven fabric can be improved.

[0084] In the drying step, the temperature of the heat roll may be 100° C. or higher (e.g., about 100 to 150° C.), preferably 110° C. or higher (e.g., about 110 to 145° C. (e.g., about 110 to 140° C.)), and more preferably 120° C. or higher (e.g., about 120 to 140° C.). The front and back sides of the raw roll may each be dried two or more times, preferably three or more times. There is no particular upper limit to the number of times that the front and back sides of the raw roll are dried, but from the viewpoint of productivity, it may be, for example, eight times or less (preferably seven times or less). EXAMPLES

[0085] 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.

[0086] [Weight (g / m 2 )] According to JIS L 1913 "General nonwoven fabric test method" 6.2, the basis weight (g / m2) of the nonwoven fabric at the official moisture content 2 ) was measured.

[0087] Thickness According to JIS L 1913 "General nonwoven fabric test method" 6.1, pressing pressure: 12g / cm 2 The thickness of the nonwoven fabric was measured using a measuring instrument with a diameter of 1.0 inch on the pressure plate.

[0088] [Binder adhesion rate] The filter paper (made of polypropylene) was dried completely, and the absolute 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 absolute dry weight was measured as B (g). The residue that was not dissolved in sulfuric acid and was left after filtration was regarded as the amount of binder attached to the fibers, 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 ratio of the obtained adhesion amount C of the binder to the total basis weight of the nonwoven fabric was expressed as a percentage and defined as the adhesion rate of the binder. In addition, when the amount of binder attached can be calculated from the manufacturing conditions, the amount of binder attached may be a value calculated from the manufacturing conditions.

[0089] [Stress at 20% elongation / breaking strength] The nonwoven fabric was cut to a width of 5 cm and a length of 15 cm, and pulled at a speed of 20 cm / min using a Shimadzu Autograph AGX-V with a chuck distance of 10 cm. The stress at 20% elongation was read from the obtained measurement chart and recorded as the stress at 20% elongation. The strength at break was also measured and recorded as the breaking strength. This measurement was performed in each of the MD, CD, and bias directions using nonwoven fabrics at 300% wetness and at the official moisture content. For nonwoven fabrics at saturated moisture content, the stress at 20% elongation and breaking strength in the bias were measured.

[0090] [Softness of nonwoven fabric when wet] A nonwoven fabric (200% wet) with a long side of 30 cm and a short side of 5 cm was placed on a horizontal surface with the MD or CD of the nonwoven fabric as the long side, and the curved shape of the approximately center part of the nonwoven fabric that was created when the nonwoven fabric was folded in half, i.e., the curved shape of the nonwoven fabric formed by lifting one short side and folding it over the other short side, was observed from the side of the nonwoven fabric, and the distance from the horizontal plane to the maximum height of the curved shape was measured. The maximum height was determined by measuring five samples cut from the same nonwoven fabric and averaging the measurements.

[0091] [Washing durability (shape change)] According to the JIS L 0217 103 method, after 30 washes, the nonwoven fabric was evaluated for changes in shape, the presence or absence of tears, and the number of pills according to the following criteria.

[0092] (Dimensional change rate) As shown in Figure 5, a rectangular nonwoven fabric sample with the MD of the nonwoven fabric as the long side and the CD as the short side was spread out, and a ruler was placed along the measurement direction of the sample at a position 10 cm away from the end of the nonwoven fabric sample to be measured. Then, as shown in Figure 6, the ruler was lightly pressed against the nonwoven fabric sample and slid to measure the length of the side of the flattened sample in the measurement direction. Based on the measured length of the nonwoven fabric, a length measuring plate as shown in Figure 7 was made. On the length measuring plate, a rectangle with two long sides A0, B0 and two short sides C0, D0 of the nonwoven fabric sample was drawn, and the center lines of each side were drawn. The center lines of the sides of the nonwoven fabric sample were also drawn with oil-based marker.

[0093] After washing the nonwoven fabric sample 30 times, the washed nonwoven fabric sample was placed on the measuring plate so that the center line of the nonwoven fabric sample coincided with the center line of the measuring plate, and the dimensional change rate of the nonwoven fabric sample was calculated based on the measuring plate. As a specific method for calculating the rate of change, for example, as shown in FIG. 8, when the long sides A0 and B0 of the length measuring plate are shrunk by A1 and A2, and B1 and B2 at both ends, the rate of dimensional change of the long sides A0 and B0 of the nonwoven fabric sample after washing is calculated by subtracting the amount of shrinkage, It can be calculated as (A0-A1-A2) / A0×100 and (B0-B1-B2) / B0×100, and the average value of these can be used as the dimensional change rate of the long side of the nonwoven fabric sample.

[0094] In addition, as shown in FIG. 9, when the short sides C0 and D0 of the measuring plate are elongated by C1 and C2, and D1 and D2 at both ends, respectively, the dimensional change rates of the short sides C0 and D0 of the nonwoven fabric sample after washing are calculated by adding up the elongations, It can be calculated as (C0+C1+C2) / C0×100 and (D0+D1+D2) / D0×100, and the average value of these can be used as the dimensional change rate of the short side.

[0095] (tear) For the nonwoven fabric samples after washing, the number of places where the nonwoven fabric was torn by 10 mm or more on the two short sides of the nonwoven fabric was counted, and the average of these was evaluated as the torn places of the nonwoven fabric sample. The average value of five repetitions was adopted as the value of the torn place.

[0096] (Fuzzball) A 20 cm square was drawn in the center of each nonwoven fabric sample before washing with a permanent marker. After 30 washes, the number of pillings that occurred within the square was counted. of The number of pills was counted on both the front and back of the nonwoven fabric sample, and the average of these was evaluated as the number of pills of the nonwoven fabric sample. The average value of five repetitions was adopted as the value of the number of pills.

[0097] [Suction length (mm)] In accordance with the Byreck method of JIS L 1907 7.1.2, three test pieces were taken in each of the vertical and horizontal directions, and adjusted so that the bottom ends were immersed in water (2% water-based ink solution). The height of the water that had risen after one minute was read, and the average value of the three pieces was recorded as the wicking length.

[0098] [Water retention capacity, water retention rate (g, %)] The measurement was made according to the water absorption rate specified in JIS L 1907 7.2. The test piece was cut into a 5 cm square and the weight A (g) was measured. The test piece was immersed in water for 30 seconds. After immersion, one side of the test piece was pinched and removed from the liquid, and the weight B (g) after 1 minute was measured as the amount of water retention. water The rate C (%) is calculated using the following formula: C(%)=[(B A) / A]×100 The calculation was made as follows.

[0099] [Example 1] A fiber web was produced by 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 polyester fiber (Tetoron (registered trademark) 471 manufactured by Toray Industries, Inc.) with a fineness of 1.6 dtex and a fiber length of 51 mm, and spinning the web using a parallel card to form a cross web using a cross wrapper. Then, a semi-random carded web made of fibers of the same composition was laminated so that the basis weight of each web was 65:35 for the cross web:semi-random web, thereby producing a fiber web. The web was placed on a metal punching drum (first drum) with an aperture of φ0.04 mm and an aperture ratio of 9.5%, and while suctioning, a water flow of 1 MPa was applied to the web from an orifice with an aperture of φ0.08 mm and a pitch of 0.6 mm, and a water flow of 3 MPa was also applied from an orifice with an aperture of φ0.1 mm and a pitch of 0.6 mm. The web was then turned over and placed on a second drum, and a high-pressure water flow of 5 MPa was applied to the web from an orifice with an aperture of φ0.1 mm and a pitch of 0.6 mm, and a high-pressure water flow of 6 MPa was also applied from an orifice with an aperture of φ0.1 mm and a pitch of 0.6 mm. The web was then turned over and placed on a #10 plain weave polyester net conveyor, and while suctioning, a high-pressure water flow of 6 MPa was applied to the web three times from an orifice with an aperture of φ0.1 mm and a pitch of 0.6 mm. The moisture content of the nonwoven fabric raw roll in which the fibers were entangled by the above-mentioned hydroentanglement treatment was adjusted to 120% by mass, and a binder (acrylic emulsion) adjusted to a solid concentration of 40% and a viscosity of 100 to 150 mPa·s was applied to form a corrugated pattern with a pitch of 5.7 mm between adjacent corrugations. After that, using a cylinder-type dryer, the surface temperature of the drying treatment roll was set to 160°C, and the nonwoven fabric was treated alternately on both sides 10 times. Next, the surface temperature of the heat treatment roll was set to 140°C, and the nonwoven fabric was treated alternately on both sides 20 times. This series of processing was carried out at a speed of 30 m / min (final drying treatment process) to produce a mesh-structured nonwoven fabric.

[0100] [Example 2] A mesh-structured nonwoven fabric was produced in the same manner as in Example 1, except that 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 was used, hydroentangled under the conditions shown in Table 1, and the pitch between the corrugations formed by the binder was set to 5.2 mm.

[0101] [Example 3] A mesh-structured nonwoven fabric was produced in the same manner as in Example 1, except that 80% 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 and 20% by mass of polyester fiber (Tetoron (registered trademark) 471 manufactured by Toray Industries, Inc.) having a fineness of 1.6 dtex and a fiber length of 51 mm were used and hydroentangled under the conditions shown in Table 1, that the web was stretched in the MD using a drafter to adjust the basis weight, and that the series of processes was carried out at a speed of 15 m / min (final drying treatment step).

[0102] [Example 4] The fibers were 100% by mass of rayon fibers (Corona, manufactured by Daiwabo Rayon Co., Ltd.) with a fineness of 1.7 dtex and fiber length of 40 mm, and were hydroentangled under the conditions shown in Table 1. After hydroentanglement, the fibers were treated with a deep nip to add a binder (acrylic emulsion) of approximately 3.0 g / m 2A mesh-structured nonwoven fabric was produced in the same manner as in Example 2, except that a binder (acrylic emulsion) with a solid content of 40% and a viscosity of 100 to 150 mPa s was applied, the surface temperature of the heat treatment roll was set to 140°C, and the front and back of the nonwoven fabric were repeatedly treated 20 times to form a wavy pattern with a pitch of 12.4 mm.

[0103] [Example 5] A mesh-structured nonwoven fabric was produced in the same manner as in Example 1, except that 50% 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 and 50% by mass of core: polyester / sheath: polyethylene composite fiber ("TJ04CEK" manufactured by Teijin) having a fineness of 2.2 dtex and a fiber length of 51 mm were used and hydroentangled under the conditions shown in Table 1.

[0104] [Example 6] A mesh-structured nonwoven fabric was produced in the same manner as in Example 2, except that hydroentanglement was performed under the conditions shown in Table 1.

[0105] [Comparative Example 1] A fiber web was produced by parallel carding using 90% by mass of rayon fiber ("Corona" manufactured by Daiwabo Rayon Co., Ltd.) with a fineness of 1.7 dtex and fiber length of 40 mm, and 10% by mass of modified polyester bicomponent fiber ("TJ04C2" manufactured by Teijin Co., Ltd.) with a fineness of 2.2 dtex and fiber length of 51 mm, core: polyester, sheath:. Water flows at pressures of 1 MPa and 4 MPa were applied on a metal punching drum (first drum). The web was then turned over and placed on a second drum where high-pressure water flows at pressures of 5 MPa and 6 MPa were applied. The web was then turned over and placed on a #6 plain-woven polyester net conveyor, and while being suctioned, a high-pressure water flow at a pressure of 6 MPa was applied to the fiber web from an orifice with a diameter of φ0.1 mm and a pitch of 0.6 mm. 1 time, 8Mpa high pressure water flow 1 time, 9Mpa high pressure water flow 1 timeThe water temperature used in the hydroentanglement was 20°C. After that, a cylinder dryer was used to set the surface temperature of the drying roll to 160°C, and the front and back sides of the nonwoven fabric were repeatedly treated 10 times, and a binder (acrylic emulsion) was applied by dip nip treatment. Next, the surface temperature of the heat treatment roll was set to 140°C, and the front and back sides of the nonwoven fabric were repeatedly treated 20 times. This series of processing was carried out at a speed of 25 m / min (final drying process), and a mesh-structured nonwoven fabric was produced.

[0106] [Comparative Example 2] table The results are shown in Table 1. 2 A mesh-structured nonwoven fabric was produced in the same manner as in Example 1, except that the mixture was (solid content).

[0107] [Comparative Example 3] A mesh-structured nonwoven fabric was produced in the same manner as in Example 2, except that hydroentanglement was performed under the conditions shown in Table 1.

[0108] [Comparative Example 4] 100% by mass of rayon fiber (Daiwabo Rayon's Corona) with a fineness of 1.7 dtex and fiber length of 40 mm was used, and the weight per unit area was approximately 50.0 g / m using a semi-random card. 2 A mesh-structured nonwoven fabric was produced in the same manner as in Example 4, except that the semi-random fiber web was hydroentangled under the conditions shown in Table 1 and the amount of binder (acrylic emulsion) applied was adjusted to a solids concentration of 40% and a viscosity of 100 to 150 mPa s.

[0109] The structure and properties of the obtained nonwoven fabric are shown in Tables 1 and 2.

[0110] [Table 1] [Table 2]

[0111] As shown in Tables 1 and 2, in Comparative Example 1, the bias stress (N / 5 cm) at 20% elongation in the bias direction of the nonwoven fabric when saturated with moisture and when 300% wet, and the basis weight (g / m 2 ) and the ratio (bias stress / basis weight) is 0.09 Yes The dimensional change rate was large after 30 washes, and many tears occurred after 30 washes.

[0112] In Comparative Example 2, since there was no binder attachment site, not only did the nonwoven fabric lose its original shape after 30 washes, but a large amount of pilling occurred. In addition, since there was no binder attachment site in Comparative Example 2, the breaking strength at saturated moisture tended to decrease.

[0113] In Comparative Example 3, the same material as in Example 2 was used, but the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric was saturated with moisture and 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture content were 2 The ratios of the bias stress to the fabric weight (bias stress / basis weight) were 0.09 and 0.08, respectively, so the dimensional change rate was large after 30 washes, and many tears occurred after 30 washes. Furthermore, the breaking strength and 20% stress were lower than those of Example 2 in all directions, MD, CD, and bias.

[0114] In Comparative Example 4, a nonwoven fabric was obtained by changing the conditions of Example 4. The bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric was saturated with moisture and 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture content were measured. 2 The ratios of the dimensional change after 30 washes (bias stress / basis weight) were 0.09 and 0.10, respectively, and the dimensional change rate after 30 washes was larger than that of Example 4, and many tears still occurred after 30 washes. Furthermore, the breaking strength and 20% stress in the CD and bias directions were significantly lower than those of Example 4.

[0115] On the other hand, in Examples 1 to 6, not only did they have high water absorbency, but also the ratio (bias stress / basis weight) was 0.15 or more and they had binder attachment sites, so all of them were able to reduce the dimensional change rate after 30 washes. In addition, no tears occurred even after 30 washes, and the nonwoven fabric of Example 1 was in the state shown in Figure 10 even after 30 washes, and the other Examples were in a similar state. [Industrial Applicability]

[0116] As described above, the nonwoven fabric of the present invention has excellent washing durability and is therefore useful as a cleaning nonwoven fabric that can be washed and reused, and can be suitably used as various industrial wipers or household wipers, for example, wipers used for wiping various electrical appliances, furniture (e.g., tables, chests of drawers, etc.), kitchen utensils (e.g., cutting boards, counters, sinks, gas stoves, tableware, etc.), as well as window glass, ceilings, floors, walls, etc.

[0117] As described above, the preferred embodiment of the present invention has been described with reference to the drawings, but various additions, modifications, and deletions can be made without departing from the spirit of the present invention, and such additions, modifications, and deletions are also included in the scope of the present invention.

[0118] 10. Nonwoven fabric roll 11. Coated surface 12 Uncoated surface 30...First heat roll 31...Second heat roll 32...Third heat roll 33...4th heat roll L1: The distance between the top and bottom of the line L2 Line width X: distance between vertices

Claims

1. A nonwoven fabric having a binder attachment portion, the bias stress (N / 5cm) at 20% elongation in the bias direction when the nonwoven fabric is saturated with moisture and / or 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture ２ ) is 0.15 or more.

2. In the wiper according to claim 1, the bias stress (N / 5 cm) at 20% elongation in the bias direction of the nonwoven fabric when saturated with moisture and / or 300% wet, and the basis weight (g / m2) of the nonwoven fabric at the standard moisture content are ２ ) ratio (bias stress / basis weight) of 0.35 or more.

3. 3. The wiper according to claim 1 or 2, wherein the ratio of the breaking strength (N / 5 cm) in the machine direction (hereinafter referred to as MD) of the nonwoven fabric at the standard moisture content to the breaking strength (N / 5 cm) in the direction perpendicular to the MD (hereinafter referred to as CD) (MD breaking strength / CD breaking strength) is 0.6 or more and less than 3.

0.

4. 3. The wiper according to claim 1 or 2, wherein the nonwoven fabric has a bias breaking strength of 25 N / 5 cm or more at the standard moisture content.

5. 3. The wiper according to claim 1, wherein the adhesion rate of the binder in the nonwoven fabric is 2 to 50 mass %.

6. The wiper according to claim 1 or 2, wherein the nonwoven fabric has an arrangement structure of fibers derived from a cross web.

7. The wiper according to claim 1 or 2, wherein the weight of the nonwoven fabric is 30 to 250 g / m ２ That's the wiper.

8. 3. The wiper according to claim 1 or 2, wherein the ratio (bias stress / average breaking strength) of the stress (N / 5 cm) at 20% elongation in the bias direction of the nonwoven fabric when saturated with moisture and / or 300% wet to the average breaking strength (N / 5 cm) in MD and CD of the nonwoven fabric when 300% wet is 0.10 to 1.

00.

9. 3. The wiper according to claim 1 or 2, wherein when a nonwoven fabric (long side 30 cm x short side 5 cm) when 200% wet is placed on a horizontal surface with either the MD or CD of the nonwoven fabric being the long side, and one short side is lifted and laid over the other short side to form a curved shape of the nonwoven fabric, when observed from the side of the nonwoven fabric, the distance from the horizontal surface to the maximum height of the curved shape is 30 mm or less in the MD and / or 30 mm or less in the CD.

10. The wiper according to claim 1 or 2, wherein the nonwoven fabric contains hydrophilic fibers in an amount of 50% by mass or more.

11. 3. The wiper according to claim 1 or 2, wherein the binder is present continuously on both sides of the nonwoven fabric.

12. 3. The wiper of claim 1 or 2, wherein the nonwoven fabric has a plurality of apertures, the colored binder forms a continuous row of wavy patterns in the CD of the nonwoven fabric, and the wavy patterns are present in a plurality of rows in the MD of the nonwoven fabric that are approximately equally spaced from one another.

13. 3. The wiper according to claim 1 or 2, wherein the water retention rate of the nonwoven fabric is 400% or more.

14. A method for producing the wiper according to claim 1 or 2, comprising the steps of: a step of subjecting the web having at least a cross-web structure to an entanglement treatment using a high-pressure water flow having a water pressure of 5 MPa or more to obtain a nonwoven fabric; applying a binder liquid to the nonwoven fabric by dip nip or coating; A method for manufacturing a wiper comprising the steps of:

15. The method for manufacturing a wiper according to claim 14, further comprising a step of drying the raw nonwoven fabric to which the binder liquid has been applied by alternately contacting the raw nonwoven fabric with a plurality of heated rolls using a cylinder type dryer.

16. The method for producing a wiper according to claim 14, wherein the temperature of the water flow in the entangling treatment is 35° C. or higher.

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