Non-woven fabric, method for producing same, and wiping cloth

Abstract

The invention provides a non-woven fabric and a wiping cloth with excellent washing durability. The non-woven fabric has an adhesive attachment site, and the ratio (bias stress / weight per unit area) of the bias stress (N / 5 cm) at 20% elongation in the bias direction when the non-woven fabric is saturated with water and / or 300% wet to the weight per unit area (g / m < 2 >) at the time of nominal moisture regain of the non-woven fabric is 0.15 or more.

Description

Technical Field

[0001] This invention relates to a nonwoven fabric with excellent washability and a method for manufacturing the same, as well as a wiping cloth. Background Technology

[0002] In recent years, the applications of nonwoven fabrics in household goods, hygiene, and medical fields have been continuously expanding. Nonwoven fabrics are sometimes used as disposable items. From an economic and environmental point of view, when used as wiping cloths for business purposes, industrial applications, etc., nonwoven fabrics that can be washed and reused are required.

[0003] For example, Patent Document 1 (Japanese Patent Application Publication No. 2008-115476) discloses a nonwoven fabric with a unit area weight of 30 to 100 g / m² formed from a fiber web containing at least rayon fibers and additionally synthetic fibers. 2 The nonwoven fabric with a mesh-like structure is characterized in that an acrylic resin is coated twice on the surface and back of the fiber web.

[0004] Patent document 2 (Japanese Patent Application Publication No. 2008-213194) discloses a non-woven fabric sheet for wiping, which is a non-woven fabric sheet with adhesive layers on the surface and back side, characterized in that the non-woven fabric sheet has an opening area of ​​2.0 to 4.0 mm. 2 Multiple through holes are arranged in a crisscross pattern, with adjacent through holes in the through hole pattern being 2.0~4.0 mm apart. The adhesive layer consists of two or more layers, with at least one adhesive layer formed on the entire surface and back of the nonwoven fabric sheet. The adhesive layers on the outermost and back layers are composed of equally spaced and parallel wavy lines, forming a wavy pattern when viewed from above.

[0005] Patent document 3 (International Publication No. 2019 / 208160) discloses a nonwoven fabric having an adhesive bonding area. In the nonwoven fabric, a cut surface randomly selected from the bonding area along the thickness direction is divided into three equal parts along the thickness direction, which are respectively designated as an upper layer, a lower layer, and a middle layer of the nonwoven fabric. Each part has a plurality of fiber bundles formed by binding and integrating multiple single fibers together with the adhesive. When the total number of single fibers present in the fiber bundles is respectively set as the total number of fibers in the upper layer bundle (Nu), the total number of fibers in the lower layer bundle (Nb), and the total number of fibers in the middle layer bundle (Nc), Nu / Nc>1.10 and Nb / Nc>1.10.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2008-115476

[0009] Patent Document 2: Japanese Patent Application Publication No. 2008-213194

[0010] Patent Document 3: International Publication No. 2019 / 208160 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] Patent documents 1 and 2 describe nonwoven fabrics as having wash durability; however, the wash durability is only evaluated by the elongation of the fibers after one cycle using an electric water tank without a spin-drying function.

[0013] Furthermore, regarding Patent Document 3, although the washing durability was evaluated using a washing machine with a spin-drying function, the washing durability was only evaluated by the fiber shape after 5 cycles.

[0014] Therefore, the object of the present invention is to provide nonwoven fabrics and wiping cloths with significantly improved washability compared to the past.

[0015] Problem Solving Methods

[0016] In order to achieve the above-mentioned objective, the inventors of the present invention conducted in-depth research and found that during washing, the laundry is subjected to stress in the washing and rinsing process when it is saturated with water, and is also subjected to stress in the dehydration process when water is released from the saturated water state under centrifugal action. Therefore, when evaluating the wash durability of nonwoven fabrics, it is important to evaluate them in the presence of a certain degree of moisture, rather than the nonwoven fabric in the dry state when it is rehydrated. In addition, the nonwoven fabric is subjected to particularly strong stress in the bias direction during the washing, rinsing and dehydration processes. Then, focusing on the stress (bias stress) at 20% elongation in the bias direction when the nonwoven fabric is saturated with water corresponding to the washing and rinsing processes, and / or the bias stress of the nonwoven fabric at 300% wetness when it is subjected to centrifugal action in the dewatering process, it was found that when the average weight per unit area of ​​the nonwoven fabric, which is standardized by the unit area weight of the nonwoven fabric, is able to increase the average weight per unit area of ​​the nonwoven fabric at 20% elongation in the bias direction, that is, when the ratio of the stress (bias stress) at 20% elongation in the bias direction at saturated water and / or 300% wetness to the unit area weight of the nonwoven fabric (bias stress / unit area weight) is able to increase, the wash durability of the absorbent nonwoven fabric can be greatly improved, thereby completing the present invention.

[0017] That is, the present invention can be constructed in the following ways.

[0018] [Method 1]

[0019] A nonwoven fabric having an adhesive attachment portion, wherein the bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% wetness is related to the standard weight per unit area (g / m²) of the nonwoven fabric at standard moisture regain. 2 The ratio of bias stress to weight per unit area is 0.15 or more (preferably 0.16 or more, more preferably 0.17 or more, and even more preferably 0.19 or more).

[0020] [Method 2]

[0021] According to the nonwoven fabric of method 1, the bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% wetness is related to the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture. 2 The ratio of bias stress to weight per unit area is 0.35 or higher.

[0022] [Method 3]

[0023] According to the nonwoven fabric of method 1 or 2, the ratio of the breaking strength (N / 5cm) of the nonwoven fabric in the mechanical direction (hereinafter referred to as MD) at the standard moisture regain to the breaking strength (N / 5cm) in the orthogonal direction (hereinafter referred to as CD) relative to MD (MD breaking strength / CD breaking strength) is 0.6 or more and less than 3.0 (preferably 0.6 to 2.9, more preferably 0.6 to 1.5).

[0024] [Method 4]

[0025] The nonwoven fabric according to any one of methods 1 to 3, wherein the bias breaking strength of the nonwoven fabric at the standard moisture regain is 25 N / 5 cm or more (preferably 30 N / 5 cm or more, more preferably 35 N / 5 cm or more, particularly preferably 45 N / 5 cm or more).

[0026] [Method 5]

[0027] The nonwoven fabric according to any one of methods 1 to 4, wherein the adhesion rate of the adhesive is 2 to 50% by mass (preferably 3 to 40% by mass, more preferably 4 to 30% by mass, particularly preferably 5 to 20% by mass).

[0028] [Method 6]

[0029] The nonwoven fabric according to any one of methods 1 to 5 has an arrangement structure of fibers derived from a cross-linked network.

[0030] [Method 7]

[0031] The nonwoven fabric according to any one of methods 1 to 6 has a unit area weight of 30 to 250 g / m². 2 (Preferred size: 35~200g / m) 2 Approximately, more preferably 40~150g / m 2 ).

[0032] [Method 8]

[0033] According to any one of the methods 1 to 7, the ratio of the stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% wetness to the average breaking strength (N / 5cm) of MD and CD of the nonwoven fabric at 300% wetness (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).

[0034] [Method 9]

[0035] According to any one of methods 1 to 8, a nonwoven fabric (30cm long side × 5cm short side) at 200% moisture content is placed on a horizontal surface with either the MD or CD of the nonwoven fabric as the long side, and one short side is lifted and overlapped with the other short side to form a curved shape of the nonwoven fabric. When the curved shape of the nonwoven fabric is viewed from the side of the nonwoven fabric, the distance from the horizontal surface to the maximum height of the curved shape is 30mm or less (preferably 25mm or less, more preferably 22mm or less) on the MD and / or 30mm or less (preferably 25mm or less, more preferably 20mm or less) on the CD.

[0036] [Method 10]

[0037] The nonwoven fabric according to any one of methods 1 to 9 contains 50% by mass or more of hydrophilic fibers (preferably 60% by mass or more, more preferably 70% by mass or more).

[0038] [Method 11]

[0039] The nonwoven fabric according to any one of methods 1 to 10, wherein the adhesive is continuously present on the surface and back of the nonwoven fabric.

[0040] [Method 12]

[0041] According to any one of methods 1 to 11, the nonwoven fabric has a plurality of openings, and a colored adhesive is formed on the CD of the nonwoven fabric to form a series of continuous wavy patterns, which exist on the MD of the nonwoven fabric at substantially equal intervals between the multiple columns of the wavy patterns.

[0042] [Method 13]

[0043] The nonwoven fabric according to any one of methods 1 to 12 has a water retention rate of 400% or more (preferably about 500%, more preferably 600% or more).

[0044] [Method 14]

[0045] A wiping cloth, which is made of any one of the nonwoven fabrics described in methods 1 to 13.

[0046] [Method 15]

[0047] A method for manufacturing a nonwoven fabric, the method comprising:

[0048] The process of obtaining nonwoven fabric by interlacing a web with at least a cross-linked structure with high-pressure water flow of 5 MPa or higher, and...

[0049] The process of applying an adhesive liquid to the nonwoven fabric by impregnation, clamping, or coating.

[0050] [Method 16]

[0051] The method for manufacturing nonwoven fabric according to method 15 comprises:

[0052] The process of using a rotary dryer involves alternating contact between the nonwoven fabric with adhesive solution and multiple hot rollers for drying.

[0053] [Method 17]

[0054] According to the nonwoven fabric manufacturing method of method 15 or 16, the temperature of the water flow in the weaving process is 35°C or higher (preferably 40°C or higher).

[0055] Here, the offset direction refers to the direction that is 45° clockwise relative to CD and 45° counterclockwise relative to MD, respectively, relative to the mechanical direction of the nonwoven fabric when it is properly re-moistened (hereinafter referred to as MD) and the direction orthogonal to MD (hereinafter referred to as CD).

[0056] Saturated moisture refers to the state where nonwoven fabric is placed in a container, water is poured into the container, and the nonwoven fabric is left to be completely immersed in water for 60 minutes, and then it is removed from the container without squeezing out the water.

[0057] 300% wet refers to the state where, relative to the standard re-moistening mass of the nonwoven fabric, the nonwoven fabric absorbs three times its mass of water and is left for 15 minutes until the moisture is evenly penetrated throughout the entire nonwoven fabric.

[0058] The standard rehydration time refers to the state in which the nonwoven fabric reaches a constant mass when the nonwoven fabric is placed under standard conditions (20±2℃, relative humidity 65±2%).

[0059] As used in this specification, the singular forms “a,” “an,” and “the” are intended to include the plural form of “at least one,” unless otherwise expressly stated. As used in this specification, the terms “and / or,” “at least one,” and “more than one” include any and all combinations of the relevant listed items.

[0060] It should be noted that any combination of at least two constituent elements disclosed in the claims and / or description and / or drawings is also included in this invention. In particular, any combination of two or more claims recited in the claims is also included in this invention.

[0061] The effects of the invention

[0062] This invention can greatly improve the wash durability of absorbent nonwoven fabrics. Therefore, absorbent nonwoven fabrics can be reused by washing them normally in a washing machine. For example, they can be used as wiping cloths for industrial use, business use, etc., for repeated washing. Attached Figure Description

[0063] The invention will be more clearly understood through the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to limit the scope of the invention. The scope of the invention is defined by the appended claims.

[0064] Figure 1 It is a schematic top view used to illustrate the generally linear attachment area.

[0065] Figure 2 It is a schematic top view used to illustrate the attachment points of the wave shape.

[0066] Figure 3 This is a schematic three-dimensional diagram of a nonwoven fabric used to illustrate a method for measuring the maximum height of the curved surface shape of the approximate central portion formed by folding the nonwoven fabric in half.

[0067] Figure 4 This is a schematic diagram illustrating the process of drying a nonwoven fabric coated with adhesive.

[0068] Figure 5 This is a schematic top view illustrating a method for measuring the side length of a nonwoven fabric sample before washing.

[0069] Figure 6This is a schematic top view illustrating a method for measuring the side length of a nonwoven fabric sample before washing.

[0070] Figure 7 This is a schematic top view showing a length measuring plate used to determine the rate of dimensional change of a nonwoven fabric sample after washing.

[0071] Figure 8 This is a schematic top view illustrating a method for measuring nonwoven fabric samples that have been washed 30 times, placed on a measuring plate, and subtracting the portion that has shrunk relative to the measuring plate.

[0072] Figure 9 This is a schematic top view illustrating a measurement method for placing a washed nonwoven fabric sample (after 30 washes) on a length measuring plate, with the portion elongated relative to the measuring plate added.

[0073] Figure 10 This is a photograph of the nonwoven fabric obtained in Example 1 after washing.

[0074] Figure 11 This is a photograph of the nonwoven fabric obtained in Comparative Example 3 after washing.

[0075] Symbol Explanation

[0076] 10. Non-woven fabric

[0077] 11··· Apply to face

[0078] 12···Non-coating surface

[0079] 30··· First Hot Roller

[0080] 31···Second Hot Roller

[0081] 32··· Third hot roller

[0082] 33··· Fourth Hot Roller

[0083] The distance between the top and bottom of line L1

[0084] L2...line width

[0085] X···Distance between vertices Detailed Implementation

[0086] The nonwoven fabric of the present invention is a water-absorbing nonwoven fabric having an adhesive-based bonding surface. The bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% wetness, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture are... 2 The ratio of bias stress to weight per unit area is 0.15 or higher. The characteristics of nonwoven fabrics will be explained below.

[0087] One type of nonwoven fabric has adhesive attachment sites. Here, the adhesive attachment site refers to the area where the adhesive is applied to the constituent fibers of the nonwoven fabric; typically, this site refers to the portion where the adhesive adhered to the fibers can be visually confirmed by observing the surface of the nonwoven fabric. Alternatively, the nonwoven fabric of the present invention may partially have adhesive attachment sites and non-adhesive sites. Here, the non-adhesive site refers to the portion where the adhesive adhesion cannot be visually confirmed by observing the surface of the nonwoven fabric. It should be noted that when the nonwoven fabric has a mesh structure, the openings based on the mesh structure are not included in the non-adhesive sites.

[0088] Here, regarding the adhesion of adhesive to fibers, if the adhesive is colored, it can be determined by coloring the adhesive; if the adhesive is transparent, it can be determined by dyeing the adhesive.

[0089] In one embodiment, the nonwoven fabric preferably has adhesive attachment portions continuously from one end to the other on at least one surface, preferably on both the surface and back of the nonwoven fabric. In the case of continuous adhesive attachment portions from one end to the other, the adhesive can be formed as planar attachment portions or linear attachment portions on the MD or CD of the nonwoven fabric, for example. When at least one surface of the nonwoven fabric has continuous adhesive attachment portions from one end to the other, the constituent fibers of the nonwoven fabric can be efficiently bound by the adhesive.

[0090] The linear attachment portion can have various shapes depending on the width of the line. The linear attachment portion can be a shape in which the lines do not intersect each other, or a shape in which the lines intersect each other at least partially. Such shapes can be striped (e.g., straight stripes, curved stripes, etc.), grid-like, etc.

[0091] It should be noted that when at least some of the lines intersect each other, one can focus on a given line from the perspective of shortening the distance from one end to the other, and grasp the shape of the linear attachment point for that line. In this case, the line may share intersection points with other lines.

[0092] For example, Figure 1 and Figure 2 A schematic diagram is shown to illustrate the linear attachment site. (For example...) Figure 1As shown, for example, regarding any linear attachment site arbitrarily selected on at least one nonwoven fabric surface, the ratio (L1 / L2) of the distance L1 between the top and bottom of the line to the line width L2 can be, for example, 1 or more, preferably 1.5 or more, for example, 10 or less, preferably 8 or less. From the viewpoint of improving fiber fixation, L1 / L2 is preferably 1.5 or more. Here, L1 represents the distance between the top and bottom measured within a 15 cm range from one end of the linear attachment site, and L2 represents the average line width measured 5 times every 2 cm within this range. It should be noted that the line width refers to the line width in a direction orthogonal to the length direction of the line.

[0093] For example, such as Figure 1 As shown, when the ratio of the distance L1 between the top and bottom of the line to the width L2 of the line (L1 / L2) is greater than 1 and less than 1.5, the attached part of the line can be regarded as a roughly straight line containing a uniform width (L1 / L2=1).

[0094] On the other hand, such as Figure 2 As shown, when the ratio (L1 / L2) between the distance L1 between the top and bottom of the line and the width L2 of the line is 1.5 or more, the linear attachment portion can form a wave-shaped attachment portion. The waveform can have various shapes such as sine wave, rectangular wave, triangular wave, sawtooth wave, etc., and is preferably sine wave.

[0095] The linear attachment sites can form multiple columns, preferably multiple columns with equal intervals between them.

[0096] Preferably, the CD has multiple linear attachment sites formed by multiple columns from one end to the other without interruption, and the multiple columns exist on the MD with substantially equal intervals between them.

[0097] For example, the distance (spacing) between columns can be 2~10mm, preferably 3~8mm. Here, spacing refers to the distance from the top of one column to the top of the next column, for example, using... Figure 2 X represents.

[0098] From a strength perspective, the weight per unit area of ​​a certain type of nonwoven fabric can be, for example, 30~250 g / m². 2 The optimal value is 35~200g / m³. 2 Around 40~150g / m 2 It should be noted that the weight per unit area is a value determined by the method described in the examples below, and it includes the weight of the adhesive.

[0099] The thickness of a nonwoven fabric can be appropriately determined according to its application, and there is no particular limitation on the thickness. For example, from the viewpoint of softness, the thickness can be 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. It should be noted that the thickness is a value measured by the method described in the embodiments described later.

[0100] From the viewpoint of water absorption, the water retention rate of a nonwoven fabric can be, for example, 400% or more, preferably around 500% or more, and more preferably around 600% or more. There is no particular upper limit, and it can be around 900%. It should be noted that the water retention rate is a value measured using the method described in the examples below.

[0101] Characteristics of nonwoven fabrics when wet

[0102] By evaluating nonwoven fabrics based on their characteristics when wet, the wash durability of nonwoven fabrics can be effectively assessed.

[0103] For a given type of nonwoven fabric, from the viewpoint of improving durability against stress applied during washing, the stress (bias stress) at 20% elongation in the bias direction, normalized to the unit area weight of the nonwoven fabric, exists within a given range in the wet nonwoven fabric. For example, the bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% wetness is related to the unit area weight (g / m²) of the nonwoven fabric. 2 The ratio of bias stress to weight per unit area is 0.15 or higher, preferably 0.16 or higher, more preferably 0.17 or higher, even more preferably 0.19 or higher, and particularly preferably 0.35 or higher. There is no particular upper limit to this ratio; from the viewpoint of the softness of the nonwoven fabric, it can be, for example, 0.90 or lower, preferably 0.80 or lower.

[0104] In one type of nonwoven fabric, when saturated with moisture and / or 300% wetted, the bias stress at 20% elongation in the bias direction can 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, and it can be around 100 N / 5 cm. The bias stress at 20% elongation is a value measured by the method described in the examples described later.

[0105] The average weight per unit area (g / m²) of a nonwoven fabric at saturated moisture and / or 300% wetness. 2The MD stress (N / 5cm) at 20% elongation on the MD of the material can be, for example, 0.40 or more, preferably 0.60 or more, and more preferably 0.70 or more. The upper limit of this ratio can be, for example, 1.0 or less.

[0106] The average weight per unit area (g / m²) of a nonwoven fabric at saturated moisture and / or 300% wetness. 2 The CD stress (N / 5cm) at 20% elongation on the CD can be, for example, 0.10 or more, preferably 0.13 or more, and more preferably 0.15 or more. The upper limit of this ratio can be, for example, 0.50 or less.

[0107] Furthermore, from the viewpoint of further improving wash durability, the ratio of the stress (N / 5cm) at 20% elongation in the bias direction of a nonwoven fabric at saturated moisture and / or 300% wetness to the average breaking strength (N / 5cm) of the MD and CD of the nonwoven fabric at 300% wetness (bias stress / average breaking strength) can be, 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.

[0108] One type of nonwoven fabric exhibits excellent softness when wet. For example, a nonwoven fabric with a long side of 30cm and a short side of 5cm (when 200% wet) 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 to create a curved shape of approximately the central part of the nonwoven fabric. That is, one short side is lifted and overlapped with the other short side to form the curved shape of the nonwoven fabric. When the curved shape is viewed from the side of the nonwoven fabric, the distance from the horizontal surface to the maximum height of the curved shape is, for example, less than 30mm on the MD, preferably less than 25mm, more preferably less than 22mm, and / or less than 30mm on the CD, preferably less than 25mm, more preferably less than 20mm.

[0109] Specifically, using Figure 3 A schematic three-dimensional diagram illustrating one method of nonwoven fabric is provided. Figure 3 The nonwoven fabric is constructed with MD as the long side and CD as the short side. Linear attachment areas are formed on the MD in multiple columns. After the nonwoven fabric reaches 200% wetness, it is temporarily laid flat on a horizontal surface. Then, one short side is lifted without moving the other, overlapping it to form a natural curve centered approximately on the long side. The softness of the nonwoven fabric when wet can be determined by measuring the maximum height of the curve formed from the horizontal surface to the nonwoven fabric.

[0110] Nonwoven fabrics exhibit a certain maximum height based on their composition. By repeating the maximum height measurement five times for samples cut from the same nonwoven fabric, the accuracy of the maximum height indicator can be improved.

[0111] [Characteristics of nonwoven fabrics during standard moisture regain]

[0112] The MD breaking strength of a nonwoven fabric at standard moisture regain can 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. There is no particular upper limit, and it can be around 250 N / 5 cm. The MD breaking strength is a value measured by the method described in the examples below.

[0113] The CD breaking strength of a nonwoven fabric at standard moisture regain can 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. There is no particular upper limit, and it can be around 320 N / 5 cm. The CD breaking strength is a value measured by the method described in the examples described later.

[0114] The average breaking strength of a nonwoven fabric at standard moisture regain is the average of the MD breaking strength and CD breaking strength, for example, it can be 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. There is no particular upper limit, and it can be around 250 N / 5 cm.

[0115] For nonwoven fabrics, from the viewpoint of suppressing deformation relative to the stress applied during washing, the ratio of the MD breaking strength (N / 5cm) to the CD breaking strength (N / 5cm) of the nonwoven fabric at standard moisture regain (MD breaking strength / CD breaking strength), which is an indicator of the orientation of the fibers of the nonwoven fabric, can 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.

[0116] The tensile strength in the bias direction of a nonwoven fabric at standard moisture regain can 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. There is no particular upper limit, and it can be around 300 N / 5 cm.

[0117] The stress at 20% elongation on the microstructure (MD) of a nonwoven fabric at standard moisture regain can 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. There is no particular upper limit, and it can be around 200 N / 5 cm. The stress at 20% elongation on the MD is a value measured by the method described in the examples below.

[0118] The stress at 20% elongation on the CD of a nonwoven fabric during standard moisture regain can 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. There is no particular upper limit, and it can be around 100 N / 5 cm. The stress at 20% elongation on the CD is a value measured by the method described in the examples below.

[0119] The stress at 20% elongation in the bias direction during the standard moisture regain of a nonwoven fabric can 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. There is no particular upper limit, and it can be around 150 N / 5 cm. The stress at 20% elongation in the bias direction is a value measured by the method described in the examples described later.

[0120] Furthermore, the ratio (bias stress / average breaking strength) of the nonwoven fabric at 20% elongation in the bias direction during standard moisture regain to the average breaking strength (N / 5cm) of the nonwoven fabric at standard moisture regain, can be, for example, 0.30 or more, preferably 0.35 or more, and more preferably 0.37 or more. There is no particular upper limit, and it can be 2.00.

[0121] The MD deformation rate of the nonwoven fabric after 30 consecutive washes can be, for example, 90-110%, preferably 93-105%. The MD deformation rate of the nonwoven fabric is a value measured by the method described in the examples below.

[0122] The CD deformation rate of the nonwoven fabric after 30 consecutive washes can be, for example, 90-110%, preferably 93-105%. The CD deformation rate of the nonwoven fabric is a value measured by the method described in the examples below.

[0123] In one type of nonwoven fabric, for example, the absorbent density (MD) length after absorbing water for 1 minute, which is an indicator of absorbency, can be 40 mm or more, preferably 45 mm or more, and more preferably 50 mm or more. There is no particular upper limit to the MD length; for example, it can be 80 mm. The MD length is a value measured by the method described in the examples below.

[0124] In one type of nonwoven fabric, for example, the CD (crystal absorbent) length after absorbing water for 1 minute, which is an indicator of absorbency, can be 40 mm or more, preferably 45 mm or more, and more preferably 50 mm or more. There is no particular upper limit to the CD length; for example, it can be 80 mm. The CD length is a value measured by the method described in the examples described later.

[0125] [The constituent fibers of nonwoven fabrics]

[0126] For the fibers constituting nonwoven fabrics, there are no particular limitations as long as the nonwoven fabric exhibits the given water absorption properties. From the viewpoint of improving water absorption, hydrophilic fibers can be included. There are no particular limitations on hydrophilic fibers; natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be used. Furthermore, hydrophilic fibers can be fibers that have been endowed with hydrophilicity through post-processing. A single hydrophilic fiber can be used, or two or more can be used in combination.

[0127] Examples of hydrophilic natural fibers include natural cellulose fibers such as cotton, linen, wool, and pulp. Examples of hydrophilic regenerated fibers include rayon, lyocell fibers such as Tencel (registered trademark), polynosic fiber, and cuprammonium cellulose fibers. Examples of hydrophilic semi-synthetic fibers include cellulose acetate and triacetate fibers. Examples of hydrophilic synthetic fibers include synthetic fibers composed of thermoplastic resins having hydrophilic functional groups such as hydroxyl, carboxyl, and sulfonic acid groups and / or hydrophilic bonds such as amide bonds. Among these, preferred hydrophilic fibers include cellulose fibers such as natural cellulose fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers. Further preferred examples include rayon fibers (e.g., viscose rayon) and solvent-spun cellulose fibers (e.g., lyocell fibers such as Tencel).

[0128] In the fibers constituting the nonwoven fabric, from the viewpoint of ensuring sufficient absorbency and water retention, the proportion of hydrophilic fibers (especially hydrophilic fibers as the main fibers) can 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 proportion of hydrophilic fibers, for example, it can be 100% by mass or less.

[0129] The fibers constituting nonwoven fabrics can include various synthetic fibers and natural fibers other than hydrophilic fibers. Examples of synthetic fibers other than the aforementioned 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, as well as composite fibers with an outer sheath made of hydrophobic resin.

[0130] In addition to the main fibers, nonwoven fabrics may also contain adhesive fibers that can fuse the fibers together through thermal or chemical bonding. Preferred adhesive fibers include fibers whose outer sheath comprises a resin component with a melting point lower than that of the main fibers. The adhesive fibers can be non-composite or composite fibers. For example, a composite fiber may have 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 and high-melting-point resins can be appropriately selected based on the melting point of the fiber-forming resins in the synthetic fiber. 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.

[0131] It should be noted that even in the case of adhesive fibers, since the adhesive fibers only form point bonds between the fibers, there are no adhesive attachment sites in the nonwoven fabric.

[0132] In the fibers constituting the nonwoven fabric, from the viewpoint of improving the softness of the nonwoven fabric, the proportion of adhesive fibers can be, for example, 30% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less.

[0133] The fiber length of the constituent fibers of the nonwoven fabric (e.g., main fibers, adhesive fibers) can be approximately 20-70 mm, preferably approximately 25-65 mm, more preferably approximately 30-60 mm, and even more preferably approximately 35-55 mm.

[0134] From the perspective of ensuring softness, the fineness of the constituent fibers of nonwoven fabric (e.g., main fibers, adhesive fibers) can be, 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.

[0135] [Adhesive]

[0136] The adhesive contains at least an adhesive component. Examples of adhesive components include acrylic resins (such as acrylate copolymer resins), polyurethane resins, vinyl acetate copolymer resins, epoxy resins, and styrene resins (such as styrene-acrylic copolymer resins), and preferably include at least one selected from acrylic resins, polyurethane resins, and styrene resins.

[0137] The adhesive may further comprise, as needed, at least one selected from pigments, penetrants, and thickeners. The pigments, penetrants, and thickeners may utilize known or conventional substances, depending on the purpose and composition. When the adhesive contains pigments, the nonwoven fabric of the present invention can be given a desired pattern by partially applying the adhesive. As described above, the smaller the ratio of the exposed area of ​​the adhesive on the surface to the back surface, the more uniform the pattern on both the surface and back surfaces of the nonwoven fabric can be obtained, resulting in superior designability.

[0138] In one type of nonwoven fabric, from the viewpoint of balancing the softness of the nonwoven fabric and the binding effect of the fibers in the nonwoven fabric, the adhesive adhesion rate can be, for example, 2 to 50% by mass, preferably 3 to 40% by mass, more preferably 4 to 30% by mass, and particularly preferably 5 to 20% by mass. Here, the adhesive adhesion rate is a value measured by the method described in the examples described later.

[0139] This type of nonwoven fabric boasts excellent washability, allowing for easy washing in a washing machine. Even with repeated washing, its durability remains excellent, making it useful as a cleaning cloth for business or industrial applications. Furthermore, it can be easily washed in a washing machine in the home, reducing daily chores time.

[0140] (Manufacturing method of nonwoven fabric)

[0141] The method for manufacturing the nonwoven fabric of the present invention comprises at least the following:

[0142] The process of obtaining nonwoven fabric by interlacing a web with at least a cross-linked structure with high-pressure water flow of 5 MPa or higher, and...

[0143] The process of applying an adhesive liquid to the nonwoven fabric by impregnation, clamping, or coating.

[0144] [Non-woven fabric]

[0145] Nonwoven fabric can be prepared by the following methods. First, given fibers are formed into a web using carding or air-laid methods. 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 at 300% wetness, the web should at least have a cross-laid structure, which can be formed by incorporating a cross-laid. A cross-laid is a web formed by orienting fibers approximately along the CD direction of the nonwoven fabric. Furthermore, for the cross-laid, random carding, semi-random carding, and parallel carding webs can be combined as needed.

[0146] The proportion of cross-cutting meshes relative to the overall mesh can be, for example, 30% or more by mass, preferably 45% or more by mass, and more preferably 60% or more by mass. There is no particular upper limit to the proportion of cross-cutting meshes; from the viewpoint of process throughput, it can be, for example, 95% by mass.

[0147] For example, the ratio of cross-network to semi-random network, expressed as the cross-network / semi-random network quality ratio, can be 30 / 70 to 95 / 5, preferably 45 / 55 to 90 / 10, and more preferably 60 / 40 to 90 / 10.

[0148] Next, to impart practical strength to the obtained web, a nonwoven fabric can be obtained by bonding the fibers together. As a bonding method, the fibers can be three-dimensionally bound together using a water-jet interlacing method.

[0149] In the water flow interlacing method, high-pressure water is sprayed from nozzles with micro-holes onto a porous support on which a net is placed. The water flow that passes through the net is reflected after contacting the steel plate, and its energy is used to make the fibers hug and bond together.

[0150] In the interlacing process, the cross-linked network is interlaced using a high-pressure water flow of 5 MPa or higher. This high-pressure water flow allows for tighter cohesion between the fibers. The high-pressure water flow can be performed multiple times with progressively increasing pressure. For example, the pressure difference between the initial and final high-pressure water flow can be 0-5 MPa, preferably 0-4 MPa.

[0151] The temperature of the water flow during the weaving process can 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 flow temperature can be appropriately set according to the type of fibers constituting the web, for example, it can be below 80°C.

[0152] Multiple porous supports can be used. For example, fibers with three-dimensional shapes can be bound together using a first porous support, and the desired mesh structure can be imparted to the nonwoven fabric using a second porous support. In this case, the second porous support can have a pattern shape corresponding to the desired mesh structure.

[0153] It should be noted that a pre-weaving process can be performed before high-pressure water flow treatment. In the pre-weaving process, a water flow with a pressure of less than 5 MPa can be used for weaving. Preferably, the pre-weaving water flow can be weaved at a pressure of 0.5~4 MPa, more preferably 0.8~3.5 MPa.

[0154] From the perspective of adjusting to a specific adhesive distribution, the unit area weight of the nonwoven fabric can be, for example, 10 g / m². 2 Above and below 100g / m2 The preferred value is 20~95g / m³. 2 Around 30~90g / m 2 about.

[0155] (Adhesive application process)

[0156] The nonwoven fabric (hereinafter sometimes simply referred to as the base fabric) is supplied for processes in which an adhesive liquid is applied by impregnation, clamping, or coating. The adhesive liquid can be used in the form of an emulsion obtained by dispersing the aforementioned adhesive components and other arbitrary components in an aqueous solvent such as water, as needed. When used in emulsion form, the viscosity of the adhesive can be appropriately determined by adjusting the concentration of solid components, depending on the method of applying the adhesive and the coating amount. For example, the concentration of solid components can be selected from a range of 0.2% by mass to 60% by mass, and the viscosity can be selected from a range of 1 to 500 mPa·s.

[0157] In the case of coating, the adhesive liquid can be applied to the entire surface of the original fabric or to specific areas. Application methods include printing, spraying, and foaming; from the viewpoint of controlling the application area of ​​the adhesive, printing is preferred.

[0158] In the printing process, adhesive can be applied to the surface of the fabric in contact with the roller by bringing the fabric into contact with the roller.

[0159] During printing, adhesive can be applied according to the pattern on the surface of the final product. Such a pattern is not particularly limited and can be various linear shapes defined by L1 / L2 above.

[0160] It should be noted that the moisture content of the original fabric before coating can be adjusted to 50-450% by weight. By adjusting the original fabric to a specific moisture content before coating, the adhesive applied to the surface can be dispersed in the water held by the original fabric, allowing it to fully penetrate into the fabric. Preferably, the moisture content of the original fabric before coating is 80-350%, more preferably 100-200%.

[0161] In the case of impregnation clamping, the original fabric is impregnated with an adhesive solution, and then, in order to remove excess adhesive solution, the original fabric is squeezed using a device such as a squeezing machine. In this case, the adhesive can penetrate the entire surface and interior of the original fabric.

[0162] When impregnating and clamping, the nonwoven fabric before being impregnated with the adhesive can be dried and used in a state with 0% moisture content. Furthermore, the adhesive content of the impregnated and clamped nonwoven fabric can be adjusted by weight to 50-800%, more preferably 80-500%, and even more preferably 100-250%. The adhesive content of the fabric can be adjusted, for example, by adjusting the conveying speed during impregnation and the pressure of the clamping rollers.

[0163] (Drying process)

[0164] Preferably, in the drying process, a rotary dryer is used, in which the surface and back of the fabric to which the adhesive solution has been applied are alternately contacted with different heated rollers to dry it. This allows the adhesive to move towards the surface of the fabric in contact with the heated rollers as moisture moves within the fabric. Specifically, on the surface of the fabric in contact with the heated rollers, as moisture evaporates, it diffuses into the areas of the fabric that are less moist due to evaporation. Along with this diffusion, solid components such as the adhesive dispersed in the water move towards the surface in contact with the heated rollers. Then, by contacting the fabric with the next heated roller, the surface of the fabric in contact with the next heated roller is further heated, thus reversing the direction of moisture diffusion. As moisture moves towards the heated rollers, solid components such as the adhesive move towards the surface in contact with the heated rollers. Therefore, even if the adhesive is applied to only one side of the surface, it can adhere to the opposite side. Moreover, by alternating the contact between the surface and back surfaces with different hot rollers for drying, solid components such as adhesives can be moved from the inside to the surface and back surfaces, resulting in a distribution of adhesives on the surface of the nonwoven fabric that is more abundant than inside the nonwoven fabric.

[0165] In addition, for example, Figure 4 As shown, when the adhesive is applied only to one side of the nonwoven fabric 10, in the drying process, the uncoated side 12, opposite to the coated side 11, is first brought into contact with the first hot roller 30, followed by the coated side 11 being brought into contact with the second hot roller 31. Further, the uncoated side 12 is brought into contact with the third hot roller 32, followed by the coated side 11 being brought into contact with the fourth hot roller 33. If necessary, the uncoated side 12 and the coated side 11 can be further brought into contact with other hot rollers alternately to dry them. In the drying process, by initially bringing the uncoated side into contact with the hot rollers, more of the solid components of the adhesive distributed on the coated side can be moved to the uncoated side while the fabric contains a large amount of moisture, which acts as a medium for the movement of solid components in the adhesive. Therefore, the uniformity of the adhesive distribution on both surfaces of the resulting nonwoven fabric can be improved.

[0166] In the drying process, the temperature of the hot roller can be above 100°C (e.g., around 100~150°C), preferably above 110°C (e.g., around 110~145°C), and more preferably above 120°C (e.g., around 120~140°C). Furthermore, the surface and back of the original fabric can be dried two or more times, preferably three or more times. There is no particular upper limit to the drying times for the surface and back of the original fabric; for example, from a production point of view, it can be eight times or less (preferably seven times or less).

[0167] Example

[0168] The present invention will now be described in more detail through examples, but the invention is not limited to these examples in any way. It should be noted that in the following examples and comparative examples, various physical properties were measured using the methods described below.

[0169] Weight per unit area (g / m²) 2 )]

[0170] According to section 6.2 of JIS L 1913 "General Test Methods for Nonwoven Fabrics", the unit area weight (g / m²) of nonwoven fabric at the standard moisture regain is determined. 2 The measurements were taken.

[0171] [thickness]

[0172] According to section 6.1 of JIS L 1913 "General Test Methods for Nonwoven Fabrics", the pressure applied is 12 g / cm. 2 Pressure plate: A 1.0-inch diameter measuring instrument was used to measure the thickness of the nonwoven fabric.

[0173] [Adhesive adhesion rate]

[0174] The filter paper (made of polypropylene) was absolutely dried, and its absolute dry weight was determined as A (g). Next, the nonwoven fabric sample was cut into 15cm squares, placed in a glass beaker, and immersed in concentrated sulfuric acid. The fibers in the nonwoven fabric were dissolved using 96% concentrated sulfuric acid solution. The resulting mixture was filtered through the aforementioned PP filter paper. Further, the residue remaining in the glass beaker was completely rinsed into the filter paper using 75% sulfuric acid solution. Then, the filter paper was rinsed with running water to remove any residual sulfuric acid. The filter paper was then absolutely dried, containing the filtered material, and its total absolute dry weight was determined as B (g). The residue that was not dissolved in sulfuric acid and filtered was considered as the amount of adhesive adhered to the fibers. The amount of adhesive adhered, C (g / m²), was calculated using the following formula. 2 ).

[0175] C(g / m 2 )=(BA) / 15 / 15×10000

[0176] Then, the percentage of the obtained adhesive adhesion amount C relative to the total unit area weight of the nonwoven fabric is taken as the adhesive adhesion rate.

[0177] It should be noted that, regarding the amount of adhesive adhered, if it can be calculated based on the manufacturing conditions, it can be the value calculated based on the manufacturing conditions.

[0178] [Stress at 20% elongation / Breaking strength]

[0179] Nonwoven fabric was cut into pieces 5cm wide and 15cm long. It was stretched using an Autograph AGX-V (manufactured by Shimadzu Corporation) at a chuck spacing of 10cm and a speed of 20cm / min. The stress at 20% elongation was recorded from the resulting measurement chart. The tensile strength at break was also measured. For this measurement, nonwoven fabrics at 300% moisture content and at standard regain moisture were used in the MD, CD, and bias directions. It should be noted that for nonwoven fabrics at saturated moisture, the stress at 20% elongation and the tensile strength at bias were measured.

[0180] [The softness of nonwoven fabric when wet]

[0181] A piece of nonwoven fabric (200% wet) with a long side of 30cm and a short side of 5cm was placed on a horizontal surface with the MD or CD of the nonwoven fabric as the long side. Folding the nonwoven fabric in half created a curved shape approximately in the center of the fabric; that is, lifting one short side and overlapping it with the other short side to form the curved shape. This curved shape was observed from the side of the nonwoven fabric, and the distance from the horizontal surface to the maximum height of the curved shape was measured. The average value of five measurements taken from samples cut from the same nonwoven fabric was taken as the maximum height.

[0182] [Washability (Morphological Change)]

[0183] According to JIS L 0217 103, after 30 washes, the morphological changes, presence of damage, and amount of pilling of the nonwoven fabric were evaluated according to the following criteria.

[0184] (Rate of Dimensional Change)

[0185] like Figure 5 As shown, unfold a rectangular nonwoven fabric sample with MD as the long side and CD as the short side. Place a ruler stationary along the measurement length direction of the sample, 10 cm from the end of the nonwoven fabric sample at a point 10 cm away from the end of the length to be measured. Then, as... Figure 6 As shown, a ruler was gently pressed against and slid across the nonwoven fabric sample to measure the length of the side along the measurement length direction of the flattened sample. Based on the measured length of the nonwoven fabric, a [material / structure] was fabricated. Figure 7 The length measuring plate shown is a rectangle with two long sides A0 and B0 and two short sides C0 and D0 of the nonwoven fabric sample. The center lines of each side are also marked on the length measuring plate. Additionally, the center lines of the sides are also marked on the nonwoven fabric sample using an oil-based pen.

[0186] After washing the nonwoven fabric sample 30 times, the washed nonwoven fabric sample was placed on the length measuring plate in such a way that the center line of the nonwoven fabric sample was aligned with the center line of the length measuring plate, and the dimensional change rate of the nonwoven fabric sample was calculated based on the length measuring plate.

[0187] As a specific method for calculating the rate of change, for example, Figure 8 As shown, when the long sides A0 and B0 of the measuring plate shrink by A1 and A2 and B1 and B2 at both ends respectively, the dimensional change rates of the long sides A0 and B0 of the washed nonwoven fabric sample, minus the shrinkage amount, can be calculated as (A0-A1-A2) / A0×100 and (B0-B1-B2) / B0×100, respectively. Their average value can be used as the dimensional change rate of the long side of the nonwoven fabric sample.

[0188] In addition, such as Figure 9 As shown, when the short sides C0 and D0 of the measuring plate are stretched 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 washed nonwoven fabric sample, plus the amount of stretching, can be calculated as (C0+C1+C2) / C0×100 and (D0+D1+D2) / D0×100, respectively. The average value obtained can be used as the dimensional change rate of the short side.

[0189] (damaged)

[0190] For the washed nonwoven fabric samples, the number of areas with tears exceeding 10 mm on both short sides of the nonwoven fabric was counted, and the average of these counts was used to evaluate the damaged areas of the nonwoven fabric sample. The average of five repeated counts was used as the damage value.

[0191] (Pilling)

[0192] Before washing, a 20cm square was drawn in the center of the nonwoven fabric sample using an oil-based pen. After 30 washes, the number of pills generated within this square was counted on both the front and back sides of the nonwoven fabric sample, and the average value was used as the pill count of the nonwoven fabric sample. The average value from 5 repetitions was taken as the pill count value.

[0193] [Lift-up length (mm)]

[0194] According to the Byreck method of JIS L 1907 7.1.2, three test pieces were collected in the longitudinal and transverse directions respectively, and the lower end was immersed in water (2% water-based ink). The height of the water rise after 1 minute was read, and the average value of the three pieces was taken as the suction length.

[0195] [Water retention capacity, water retention rate (g, %)]

[0196] The water absorption rate was determined according to JIS L 1907 7.2. The test piece was cut into 5cm squares and its weight A (g) was measured. The test piece was then immersed in water for 30 seconds. After immersion, the test piece was removed from the liquid by clamping one side, and its weight B (g) after 1 minute was measured as the water retention. The water retention rate C (%) was calculated using the following formula.

[0197] C(%)=[(BA) / A]×100

[0198] [Example 1]

[0199] Using 70% by mass of rayon fiber ("Corona" manufactured by Daiwabo Rayon Company) 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 Company) with a fineness of 1.6 dtex and a fiber length of 51 mm, the web spun by a parallel carding machine was cross-laid using a cross-laying machine. The fiber web formed by semi-random carding of fibers with the same composition was then layered with the cross-laid web: semi-random web having a unit area weight ratio of 65:35 to produce a fiber web.

[0200] The fiber web was placed on a metal perforated roller (first roller) with a diameter of 0.04 mm and an opening ratio of 9.5%. While suction was applied, a water flow of 1 MPa was applied to the fiber web through orifices with a diameter of 0.08 mm and a spacing of 0.6 mm. A further water flow of 3 MPa was applied through orifices with a diameter of 0.1 mm and a spacing of 0.6 mm. Next, the surface and back were flipped and placed on a second roller. A high-pressure water flow of 5 MPa was applied to the fiber web through orifices with a diameter of 0.1 mm and a spacing of 0.6 mm. A further high-pressure water flow of 6 MPa was applied through orifices with a diameter of 0.1 mm and a spacing of 0.6 mm. Finally, the surface and back were flipped and placed on a #10 plain weave polyester mesh conveyor. While suction was applied, a high-pressure water flow of 6 MPa was applied to the fiber web three times through orifices with a diameter of 0.1 mm and a spacing of 0.6 mm.

[0201] The moisture content of the nonwoven fabric, after undergoing the aforementioned water flow weaving process to achieve fiber cohesion, was adjusted to 120% by mass. To form a wave pattern with a spacing of 5.7 mm between adjacent waves, an adhesive (acrylic emulsion) with a solid content of 40% and a viscosity of 100-150 mPa·s was applied. Then, using a rotary dryer, the surface temperature of the drying rollers was set to 160°C, and the nonwoven fabric was alternately treated 10 times on both the front and back sides. Next, the surface temperature of the heat treatment rollers was set to 140°C, and the nonwoven fabric was alternately treated 20 times on both the front and back sides. This series of processes was performed at a speed of 30 m / min (final drying process) to produce a mesh-structured nonwoven fabric.

[0202] [Example 2]

[0203] 100% by mass of rayon fiber (Daiwabo Rayon "Corona") with a fineness of 1.7 dtex and a fiber length of 40 mm was used, and water flow interlacing was performed under the conditions described in Table 1. The spacing between the waveforms formed by the adhesive was set to 5.2 mm. Otherwise, a nonwoven fabric with a mesh structure was produced in the same manner as in Example 1.

[0204] [Example 3]

[0205] Using 80% 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 20% by mass of polyester fiber ("Tetoron (registered trademark) 471" manufactured by TORAY Co., Ltd.) with a fineness of 1.6 dtex and a fiber length of 51 mm, water-flow interlacing was performed under the conditions described in Table 1. In order to adjust the weight per unit area, the web was stretched on MD by a drawing machine and a series of processing was performed at a speed of 15 m / min (final drying process). Otherwise, a nonwoven fabric with a web structure was produced in the same manner as in Example 1.

[0206] [Example 4]

[0207] 100% by mass of rayon fiber (Daiwabo Rayon "Corona") with a fineness of 1.7 dtex and a fiber length of 40 mm was used and water-laid under the conditions described in Table 1. After water-laid, it was coated with approximately 3.0 g / m² by impregnation and padding. 2The adhesive (acrylic emulsion) of (solid component) was applied using a rotary dryer. The surface temperature of the drying roller was set to 160°C, and the surface and back of the nonwoven fabric were treated 10 times. Further, an adhesive (acrylic emulsion) with a solid component concentration of 40% and a viscosity of 100~150 mPa·s was applied. The surface temperature of the heat treatment roller was set to 140°C, and the surface and back of the nonwoven fabric were treated 20 times, forming a wavy pattern with a spacing of 12.4 mm. Otherwise, a nonwoven fabric with a mesh structure was produced in the same manner as in Example 2.

[0208] [Example 5]

[0209] A nonwoven fabric with a mesh structure was produced using 50% 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 50% by mass of composite fiber ("TJ04CEK" manufactured by Teijin Co., Ltd.) with a fineness of 2.2 dtex and a fiber length of 51 mm, with a polyester core and a polyethylene sheath. Otherwise, a nonwoven fabric with a mesh structure was produced in the same manner as in Example 1.

[0210] [Example 6]

[0211] Except for the water flow interlacing conditions described in Table 1, a nonwoven fabric with a mesh structure was produced in the same manner as in Example 2.

[0212] [Comparative Example 1]

[0213] A fiber web was made using 90% by weight 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 10% by weight of composite fiber ("TJ04C2" manufactured by Teijin Co., Ltd.) with a fineness of 2.2 dtex and a fiber length of 51 mm, with a core of polyester and a sheath of modified polyester. The fiber web was made using a parallel carding machine.

[0214] Water flow at pressures of 1 MPa and 4 MPa was applied to a perforated metal roller (roller 1). Next, the surface and back were flipped, and high-pressure water flow at pressures of 5 MPa and 6 MPa was applied to a second roller. Then, the surface and back were flipped again and placed on a #6 plain weave polyester mesh conveyor, where high-pressure water flow at 6 MPa was applied three times through orifices with a diameter of 0.1 mm and a spacing of 0.6 mm, while suction was applied. It should be noted that the water temperature used in the water flow interlacing was 20°C. Then, using a rotary dryer, the surface temperature of the drying roller was set to 160°C, and the surface and back of the nonwoven fabric were alternately treated 10 times, followed by an adhesive coating (acrylic emulsion) through an impregnation and clamping process. Next, the surface temperature of the heat treatment roller was set to 140°C, and the surface and back of the nonwoven fabric were treated 20 times. This series of processes was carried out at a speed of 25 m / min (final drying process) to produce a mesh-structured nonwoven fabric.

[0215] [Comparative Example 2]

[0216] Interlacing was performed under the conditions described in Table 1, and the adhesive application rate was set to 0 g / m. 2 (Solid components), except that a nonwoven fabric with a mesh structure was made in the same manner as in Example 1.

[0217] [Comparative Example 3]

[0218] Except for the water flow interlacing conditions described in Table 1, a nonwoven fabric with a mesh structure was produced in the same manner as in Example 2.

[0219] [Comparative Example 4]

[0220] Using 100% by weight of rayon fiber (Daiwabo Rayon's "Corona") with a fineness of 1.7 dtex and a fiber length of 40 mm, and processed using a semi-random carding machine, the resulting area weight was approximately 50.0 g / m². 2 The semi-random fiber web was water-interwoven under the conditions described in Table 1, and the coating amount of the adhesive (acrylic emulsion) with a solid content of 40% and a viscosity of 100~150 mPa·s was adjusted. Otherwise, a nonwoven fabric with a mesh structure was made in the same manner as in Example 4.

[0221] The composition and properties of the obtained nonwoven fabrics are shown in Tables 1 and 2.

[0222]

[0223]

[0224] As shown in Tables 1 and 2, in Comparative Example 1, the bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and 300% wetness, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture are compared. 2 The ratio of bias stress to weight per unit area was 0.09. The dimensional change rate after 30 washes was large, and multiple breaks occurred after 30 washes.

[0225] In Comparative Example 2, due to the absence of adhesive attachment areas, the nonwoven fabric not only deformed after 30 washes, rendering it unable to maintain its original shape, but also exhibited significant pilling. It should be noted that in Comparative Example 2, the absence of adhesive attachment areas resulted in a tendency for a decrease in tensile strength when saturated with moisture.

[0226] In Comparative Example 3, although the same materials as in Example 2 were used, the bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and 300% wetness, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture were compared. 2 The ratios (bias stress / weight per unit area) were 0.09 and 0.08, respectively, resulting in a large dimensional change rate after 30 washes and multiple breaks after 30 washes. Furthermore, the breaking strength and 20% stress were lower than those of Example 2 in any of the MD, CD, and bias directions.

[0227] In Comparative Example 4, the nonwoven fabric was obtained by changing the conditions of Example 4. However, the bias stress (N / 5cm) at 20% elongation in the bias direction at saturated moisture and 300% wetness, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture were different. 2 The ratios (bias stress / weight per unit area) were 0.09 and 0.10, respectively. The dimensional change rate after 30 washes was larger than that of Example 4, and multiple breaks still occurred after 30 washes. In addition, the breaking strength in the CD and bias directions, as well as the 20% stress, were significantly reduced compared to Example 4.

[0228] On the other hand, in Examples 1-6, not only is the absorbency high, but the aforementioned ratio (bias stress / weight per unit area) is also 0.15 or higher, and adhesive attachment sites are present, thus all of which can reduce the dimensional change rate after 30 washes. Furthermore, no damage occurred after 30 washes; the nonwoven fabric of Example 1 remained intact even after 30 washes. Figure 10 The state shown is the same in other embodiments.

[0229] Industrial applicability

[0230] As described above, the nonwoven fabric of the present invention has excellent washability and is therefore useful as a cleaning nonwoven fabric that can be washed and reused. It can be suitably used as a wiping cloth for wiping various industrial wiping cloths or household wiping cloths, for example, various electrical products, furniture (e.g., tables, wardrobes, etc.), kitchen utensils (e.g., cutting boards, cooking counters, sinks, gas stoves, tableware, etc.), as well as window glass, ceilings, floors, walls, etc.

[0231] As mentioned above, while referring to the appendix Figure 1 While the preferred embodiments of the present invention have been described, various additions, modifications or deletions can be made without departing from the spirit of the present invention, and such modifications are also included within the scope of the present invention.

Claims

1. A nonwoven fabric having an adhesive attachment portion, wherein, The bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% moisture content, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture. 2 The ratio of bias stress to weight per unit area is 0.15 or higher.

2. The nonwoven fabric according to claim 1, wherein, The bias stress (N / 5cm) at 20% elongation in the bias direction of the nonwoven fabric at saturated moisture and / or 300% moisture content, and the unit area weight (g / m²) of the nonwoven fabric at standard regain moisture. 2 The ratio of bias stress to weight per unit area is 0.35 or higher.

3. The nonwoven fabric according to claim 1 or 2, wherein, The ratio of the breaking strength (N / 5cm) of the nonwoven fabric in the mechanical direction (MD) at standard moisture regain to the breaking strength (N / 5cm) in the orthogonal direction (CD) relative to MD (MD breaking strength / CD breaking strength) is 0.6 or more and less than 3.

0.

4. The nonwoven fabric according to claim 1 or 2, wherein, The standard offset breaking strength of nonwoven fabric at regain moisture is above 25 N / 5 cm.

5. The nonwoven fabric according to claim 1 or 2, wherein, The adhesion rate of the adhesive is 2-50% by mass.

6. The nonwoven fabric according to claim 1 or 2, having an arrangement of fibers derived from a cross-linked network.

7. The nonwoven fabric according to claim 1 or 2, wherein the unit area weight is 30~250g / m². 2 .

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

00.

9. The nonwoven fabric according to claim 1 or 2, wherein, A nonwoven fabric (30cm long side × 5cm short side) at 200% moisture content is placed on a horizontal surface with either the MD or CD of the nonwoven fabric as the long side. One short side is lifted and overlapped with the other short side to form a curved shape of the nonwoven fabric. When the curved shape of the nonwoven fabric is viewed from the side, the distance from the horizontal surface to the maximum height of the curved shape is less than 30mm on the MD and / or less than 30mm on the CD.

10. The nonwoven fabric according to claim 1 or 2, comprising more than 50% by weight of hydrophilic fibers.

11. The nonwoven fabric according to claim 1 or 2, wherein, The adhesive is continuously present on both the surface and the back of the nonwoven fabric.

12. The nonwoven fabric according to claim 1 or 2, wherein, The nonwoven fabric has multiple openings, and a colored adhesive is applied to the CD of the nonwoven fabric to form a series of continuous wavy patterns. These wavy patterns exist on the MD of the nonwoven fabric with multiple columns of the wavy patterns spaced approximately equally from each other.

13. The nonwoven fabric according to claim 1 or 2 has a water retention rate of 400% or more.

14. A wiping cloth comprising the nonwoven fabric as described in claim 1 or 2.

15. A method for manufacturing a nonwoven fabric, the method comprising: The process of obtaining nonwoven fabric by interlacing a web with at least a cross-linked structure with high-pressure water flow of 5 MPa or higher. The process of applying an adhesive liquid to the nonwoven fabric by impregnation, clamping, or coating.

16. The method for manufacturing nonwoven fabric according to claim 15, wherein the method comprises: The process of using a rotary dryer involves alternating contact between the nonwoven fabric with adhesive solution and multiple hot rollers for drying.

17. The method for manufacturing nonwoven fabric according to claim 15 or 16, wherein, The temperature of the water flow during the interweaving process is above 35℃.

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