JP7627098B2 - Nonwoven fabric, its manufacturing method, and wiper - Google Patents

Description

The present disclosure relates to a nonwoven fabric that has an overall striped pattern and has greater tensile strength in the direction in which the striped pattern is repeated, and a wiper using the same.

One application of nonwoven fabrics is in wipers used to wipe dirt off the human body or objects. A wide variety of wiper configurations have been proposed depending on the purpose of the wiper (what is to be wiped off (human or object) and the type of dirt to be wiped off).

As one method for improving the wiping performance of a wiper, it has been proposed to give the nonwoven fabric a three-dimensional pattern and use the unevenness formed by the pattern to scrape off more dirt. For example, Patent Document 1 proposes a nonwoven fabric in which rows of holes, in which openings are continuously connected through, alternate with rows of non-perforated holes. In addition, Patent Document 2, in consideration of the insufficient strength characteristics of the nonwoven fabric disclosed in Patent Document 1, proposes a nonwoven fabric having a striped pattern formed by a plurality of stripes each having a regular pattern and spaced apart from each other, with the stripes having a width of 4 mm to 50 mm. In the nonwoven fabrics disclosed in these patent documents, each row that constitutes the striped pattern extends in the MD direction (machine direction, also called the longitudinal direction) of the nonwoven fabric.

JP 2000-45161 A JP 2009-287158 A

The present disclosure provides a nonwoven fabric that has greater tensile strength in a direction perpendicular to the direction in which each row of stripes extends.

The present disclosure, in a first aspect, provides a nonwoven fabric including a first entangled portion and a second entangled portion,
the first intertwined portions and the second intertwined portions are present in a striped pattern,
The second intertwined portion and the first intertwined portion have different patterns from each other, or one of the second intertwined portion and the first intertwined portion has no pattern and the other has a pattern;
A tensile strength S1 of the nonwoven fabric in a direction in which the first entangled portions extend and a tensile strength S2 of the nonwoven fabric in a direction perpendicular to the direction in which the first entangled portions extend satisfy S1<S2.
A nonwoven fabric is provided.

In a second aspect, the present disclosure provides
Producing a fibrous web;
placing the fibrous web on a support and subjecting the fibrous web to an entanglement treatment using a high-pressure fluid flow;
In the entanglement treatment, it is assumed that the fiber web has a first section and a second section extending along the CD direction in a striped pattern,
The entanglement is performed under different processing conditions when the first section of the fiber web is subjected to the entanglement treatment from the processing conditions when the second section of the fiber web is subjected to the entanglement treatment, so that the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, have different patterns, or one of the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, has no pattern, and the other has a pattern.
A method for producing a nonwoven fabric is provided.

The nonwoven fabric of the present disclosure has a tensile strength S1 in the direction in which the first and second intertwined parts that make up the striped pattern extend, and a tensile strength S2 in the direction perpendicular to that direction, such that S1 < S2. Therefore, the nonwoven fabric is less likely to deform in the direction perpendicular to the direction in which the first and second intertwined parts extend. When this is used as a wiper, for example, the striped pattern allows dirt to be wiped away effectively.

10 is a plan view showing an acute angle a formed by the oblique lines of the oblique line pattern and the extending direction of the first intertwined portions when the first intertwined portions have an oblique line pattern. FIG. 10 is a plan view showing the shortest distance D between the centers of adjacent openings when the second intertwined portion has a pattern in which the openings are arranged in a staggered manner. FIG.

(How the present embodiment was arrived at)
In both of the nonwoven fabrics disclosed in Patent Documents 1 and 2, the stripe pattern, i.e., the rows or pattern portions constituting the striped pattern, extend mainly in the MD direction of the nonwoven fabric, and the pattern (i.e., the uneven pattern) changes along the CD direction. In these nonwoven fabrics, the fibers are oriented in the MD direction, so the strength in the MD direction is large, and they are easily broken and deformed in the CD direction (also called the transverse direction). That is, when these nonwoven fabrics are used for wiping, for example, if the nonwoven fabric is placed on a dirty object and the nonwoven fabric is moved in a direction parallel to the CD direction to rub the object, the dirt on the object tends to be broken without being wiped off. Therefore, even if these nonwoven fabrics are moved in the CD direction to wipe off dirt by utilizing the change in the pattern in the CD direction, the nonwoven fabric may become twisted, and the wiping ability of the stripes may not be exhibited.

The inventors therefore believed that the above problem could be solved by configuring each row of the striped pattern to extend in a direction (e.g., CD direction) perpendicular to the direction in which the mechanical strength of the nonwoven fabric is greater (e.g., MD direction), and conducted research to realize this configuration. They discovered that a nonwoven fabric with this configuration can be obtained by imagining a fiber web in which a first section and a second section extending along the CD direction exist in a striped pattern, and performing an entanglement treatment under different processing conditions when the first section of the fiber web is subjected to the entanglement treatment and when the second section of the fiber web is subjected to the entanglement treatment, and thus arrived at this embodiment.

(Embodiment 1: Nonwoven fabric)
The nonwoven fabric described as embodiment 1 is a nonwoven fabric including a first entangled portion and a second entangled portion,
the first intertwined portions and the second intertwined portions are present in a striped pattern,
The second intertwined portion and the first intertwined portion have different patterns from each other, or one of the second intertwined portion and the first intertwined portion has no pattern and the other has a pattern;
A tensile strength S1 of the nonwoven fabric in a direction in which the first entangled portions extend and a tensile strength S2 of the nonwoven fabric in a direction perpendicular to the direction in which the first entangled portions extend satisfy S1<S2.
It is a nonwoven fabric.

[First intertwined portion and second intertwined portion]
The first entangled portion and the second entangled portion contained in the nonwoven fabric of this embodiment are present in a striped pattern and have different patterns from each other, or one of the second entangled portion and the first entangled portion has no pattern and the other has a pattern.
Here, "no pattern" means something that gives no sense of design, and although it may have, for example, uneven texture that inevitably occurs during web formation or nozzle streaks that inevitably occur during hydroentanglement treatment, no intentional pattern is imparted. More specifically, if there are protrusions, recesses, openings, etc., the longest dimension of which (in the case of continuous extension in one direction like nozzle streaks, excluding the dimension in that direction) is 0.1 mm or less, such protrusions, recesses, openings, etc. are not considered to form a pattern.

"Existing in stripes" means that these entangled portions are repeatedly present with a certain regularity as linear portions extending in a certain direction. For example, when the nonwoven fabric of this embodiment has only the first entangled portions and the second entangled portions, the first entangled portions and the second entangled portions are repeatedly present in an alternating manner. When the nonwoven fabric of this embodiment has a third entangled portion in addition to the first entangled portions and the second entangled portions, these entangled portions may be present with a regularity such as 1-2-1-3, 1-2-3, or 2-1-3, for example.

The patterns of the first intertwined portion and the second intertwined portion are not particularly limited, so long as they are different from each other, or one of the first intertwined portion and the second intertwined portion has no pattern and the other has a pattern. The pattern may be formed, for example, by regularly arranging an area with a lower fiber density ("low density area") and an area with a higher fiber density ("high density area"). In this case, the low density area may be at least one pattern selected from the group consisting of a regular pattern, for example, a dot pattern, a herringbone pattern, a checkerboard pattern, a grid pattern, a houndstooth pattern, a diagonal line pattern, a wave pattern, and a zigzag pattern.

The low-density regions may be recesses that are thinner than the high-density regions and recessed from the high-density regions, or may be openings in which no fibers are present. In one intertwining section, low-density regions may contain both recesses and openings. In particular, when openings are formed, depending on the manufacturing conditions, it may not be possible to make all low-density regions into openings, and some low-density regions may exist as recesses. Such forms are also permitted in this embodiment.

In this embodiment, the pattern of the first intertwined portion is preferably a diagonal line pattern. The diagonal line pattern is a pattern in which low-density regions and high-density regions extending in a diagonal direction are alternately arranged, and in this embodiment, the "diagonal direction" refers to a direction that is not parallel to the MD and CD directions of the nonwoven fabric. The intertwined portion having a diagonal line pattern tends to improve wiping properties when the nonwoven fabric is used as a wiper.

When the first intertwined portion has a diagonal line pattern, the acute angle a (see FIG. 1) between the diagonal line of the diagonal line pattern and the direction in which the first intertwined portion extends may be 10 degrees or more and 80 degrees or less, particularly 15 degrees or more and 75 degrees or less, more particularly 20 degrees or more and 70 degrees or less. If the acute angle a is too small, the direction of the diagonal line approaches the direction in which the first intertwined portion extends, and if the acute angle a is too large, the direction of the diagonal line approaches the direction perpendicular to the direction in which the first intertwined portion extends, and in either case, it becomes difficult to obtain an improved effect such as wiping ability. Here, the extension direction of the first intertwined portion is a direction that satisfies S1<S2, where S1 is the tensile strength of the nonwoven fabric in that direction and S2 is the tensile strength of the nonwoven fabric in the direction perpendicular to that direction, and is generally the CD direction of the nonwoven fabric. The extension direction of the first intertwined portion is also the extension direction of the second intertwined portion.

The second intertwined portion may have a pattern in which the apertures are regularly arranged. The pattern in which the apertures are regularly arranged may be, for example, a pattern in which the apertures are arranged in a staggered pattern, a pattern in which the apertures are arranged in a square pattern, etc. In the pattern in which the apertures are regularly arranged, the shortest distance between the centers of adjacent apertures may be, for example, 1.0 mm or more and 4.0 mm or less, particularly 1.3 mm or more and 3.0 mm or less, and more particularly 1.6 mm or more and 2.5 mm or less. Here, the shortest distance between the centers of adjacent apertures refers to the shortest line segment connecting the centers of adjacent apertures in all combinations. For example, when the apertures are formed in a staggered pattern as shown in FIG. 2, the shortest distance between the centers of adjacent apertures is the distance indicated by the symbol D.

When the second intertwined portion is a pattern formed by a regular arrangement of openings, the area of one opening may be, for example, 0.50 ^mm2 or less, particularly 0.45 ^mm2 or less, more particularly 0.40 ^mm2 or less. The lower limit of the area of the opening may be, for example, 0.01 ^mm2 , particularly 0.02 ^mm2 , more particularly 0.03 ^mm2 . If the area of the opening is too large, the strength of the nonwoven fabric may decrease, and when used as a wiper, the wiped dirt may adhere to the hand or tool through the openings, or the wiped dirt may easily detach from the openings. If the area of the opening is too small, it is difficult to say that a pattern is formed, and the pattern may not provide an effect of improving wiping properties.

In addition, when the second intertwined portion has a pattern formed by a regular arrangement of openings, the proportion of the openings in the second intertwined portion may be, for example, 1% to 30%, particularly 3% to 20%, and more particularly 5% to 10%. If the proportion of the openings in one intertwined portion is too small, the effect of improving wiping properties, etc., due to the formation of the openings may not be obtained. If the proportion of the openings in one intertwined portion is too large, the strength of the nonwoven fabric may decrease, and when used as a wiper, the wiped dirt may adhere to hands or tools through the openings, or the wiped dirt may be easily detached from the openings.

When either the first intertwined portion or the second intertwined portion has no pattern, the other intertwined portion may have a diagonal line pattern or a pattern formed by a regular arrangement of openings. In particular, when the other intertwined portion has a diagonal line pattern, the difference in thickness between the diagonal line pattern and the non-patterned portion becomes large, and scraping properties tend to improve when used as a wiper.

As described above, in the nonwoven fabric of this embodiment, the first and second intertwined portions exist in stripes and are repeated in a certain direction to form a pattern. When the nonwoven fabric has only the first and second intertwined portions, a striped pattern is formed in which the first and second intertwined portions alternate in a direction perpendicular to the direction in which the first and second intertwined portions extend. When the first and second intertwined portions extend parallel to, for example, the CD direction of the nonwoven fabric, the striped pattern appears in the MD direction, and when the CD direction is defined as "horizontal" and the MD direction is defined as "vertical", a horizontal striped pattern is formed in which two types of linear portions extending in the horizontal direction are alternately arranged in the vertical direction.

The first intertwined portion may have a dimension of, for example, 2 mm to 200 mm in a direction perpendicular to the direction in which the first intertwined portion extends, particularly 3 mm to 100 mm, more particularly 5 mm to 50 mm, even more particularly 7 mm to 30 mm, and even more particularly 10 mm to 25 mm. The second intertwined portion may also have a dimension of, for example, 2 mm to 200 mm in a direction perpendicular to the direction in which the first intertwined portion extends, particularly 3 mm to 100 mm, more particularly 5 mm to 50 mm, even more particularly 7 mm to 30 mm, and even more particularly 10 mm to 25 mm. The dimension of the first intertwined portion in a direction perpendicular to the direction in which the first intertwined portion extends (hereinafter referred to as "width" for convenience) and the width of the second intertwined portion may be the same or different. Furthermore, in one nonwoven fabric, there may be multiple first entangled portions with different widths, and/or there may be multiple second entangled portions with different widths.

If the width of the first intertwined portion is too small, the design effect of the striped pattern may not be fully achieved, and when the nonwoven fabric is used as a wiper, the wiping performance may be insufficient. The same applies if the width of the second intertwined portion is too small. If the width of the first intertwined portion is too large, the design effect may not be fully achieved, and the wiping performance may be insufficient. The same applies if the width of the second intertwined portion is too large.

As described above, in the nonwoven fabric of this embodiment, the tensile strength S1 of the nonwoven fabric in the direction in which the first intertwined portion extends and the tensile strength S2 of the nonwoven fabric in the direction perpendicular to the direction in which the first intertwined portion extends satisfy S1<S2. Generally, a nonwoven fabric has a larger tensile strength in the MD direction (the direction in which the distance of the nonwoven fabric extends with the manufacture of the nonwoven fabric) and a smaller tensile strength in the CD direction (the direction perpendicular to the MD direction and in which a given dimension is given when the nonwoven fabric is manufactured). Therefore, in this embodiment, the direction in which the first intertwined portion and the second intertwined portion extend is generally the CD direction of the nonwoven fabric. The tensile strength S1 (N/5 cm) and the tensile strength S2 (N/5 cm) may particularly satisfy S1+10<S2, more particularly S1+20<S2, and even more particularly S1+30<S2. Alternatively, the relationship between tensile strength S1 (N/5 cm) and tensile strength S2 (N/5 cm) may be expressed as the ratio of S2 to S1 (S2/S1). In this case, the value of S2/S1 may be particularly 2.0 or more and 20 or less, more particularly 3.0 or more and 15 or less, and even more particularly 4.0 or more and 8.0 or less.

[Fibers constituting nonwoven fabric]
The fibers constituting the nonwoven fabric of the present embodiment are not particularly limited, and any fibers used in the manufacture of nonwoven fabrics may be used.
synthetic fibers made of one or more thermoplastic resins selected from polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and copolymers thereof; polyamide-based resins such as nylon 6, nylon 66, and copolymers thereof; polyolefin-based resins such as polymethylpentene, polypropylene, and polyethylene (including high-density polyethylene, low-density polyethylene, and linear low-density polyethylene); acrylic resins, engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefins, and elastomers thereof;
Natural fibers such as cotton, silk, wool, hemp, and pulp; and regenerated fibers (including those surface-treated with hydrophobizing agents), such as viscose-derived rayon and polynosic, cupra obtained by the cuprammonium process, and cellulosic fibers obtained by the solvent-spun process (such as Lyocell and Tencel®).
It may be formed of one or more fibers selected from cellulosic fibers obtained by melt spinning processes, and semi-synthetic fibers such as acetate fibers.

The synthetic fibers may be either single fibers or composite fibers. The composite fibers may be, for example, concentric or eccentric sheath-core composite fibers, islands-in-the-sea composite fibers, side-by-side composite fibers, or split composite fibers.

The synthetic fibers may also be ones that melt or soften when heated or the like to exhibit adhesive properties. For example, the synthetic fibers may be single fibers or composite fibers that contain a resin with a relatively low melting point, such as polyethylene, as one component, with the low melting point resin component occupying at least a portion of the fiber surface. Such fibers are, for example, sheath-core composite fibers made of a combination of polyethylene/polypropylene or polyethylene/polyethylene terephthalate, with polyethylene as the sheath component, or split composite fibers made of a combination of these thermoplastic resins.

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

In the case of splittable composite fibers, the ratio of the two components (first:second) is preferably 80:20 to 20:80 by volume, more preferably 70:30 to 30:70, and even more preferably 60:40 to 40:60. In the case of splittable composite fibers, the number of divisions (i.e., the number of sections in the composite fiber) may be, for example, 4 or more and 32 or less, particularly 4 or more and 20 or less, and more particularly 6 or more and 10 or less.

When synthetic fibers capable of bonding fibers together are used, the synthetic fibers may be present in an amount of, for example, 5% by mass or more, particularly 10% by mass or more, and more particularly 15% by mass or more, when the mass of the entire nonwoven fabric is taken as 100% by mass. The upper limit of the proportion of adhesive synthetic fibers is, for example, 35% by mass, particularly 30% by mass, and more particularly 25% by mass. If the proportion of adhesive synthetic fibers is too low, the effects of bonding fibers together (e.g., improving the mechanical strength of the nonwoven fabric, suppressing fuzzing, and maintaining the applied pattern) may not be fully obtained. If the proportion of adhesive synthetic fibers is too high, the texture of the nonwoven fabric becomes hard and the drapeability decreases, which may affect wiping properties when used as a wiper.

The nonwoven fabric of this embodiment may contain, for example, 30% by mass or more, particularly 50% by mass or more, and more particularly 80% by mass or more of cellulosic fibers. Here, examples of cellulosic fibers include natural fibers derived from plants such as cotton, linen, ramie, jute, hemp, and pulp; regenerated fibers such as rayon and polynosic obtained by the viscose method, cupra obtained by the cuprammonium method, and cellulosic fibers obtained by the solvent spinning method (such as Lenzing Lyocell (registered trademark) and Tencel (registered trademark)), cellulosic fibers obtained by the melt spinning method, and semi-synthetic fibers such as acetate fibers. Cellulosic fibers, particularly when a nonwoven fabric is produced by an entanglement treatment using a high-pressure fluid flow, tend to entangle the fibers with each other, providing a nonwoven fabric in which the entangled state is well maintained even after the entanglement treatment, making it easy to form a clear pattern on the nonwoven fabric. In addition, the fibers are well entangled with each other, which suppresses fluffing of the nonwoven fabric.

The fiber fineness is not limited as long as a pattern is formed in both or either of the first and second entangled portions, and is selected according to the use of the nonwoven fabric. The fiber fineness may be, for example, 0.3 dtex to 10 dtex, particularly 0.5 dtex to 5.0 dtex, more particularly 0.7 dtex to 4.0 dtex, even more particularly 1.0 dtex to 3.0 dtex, and even more particularly 1.3 dtex to 2.5 dtex. When the fibers constituting the nonwoven fabric are natural fibers such as cotton, it may be difficult to use fibers in a specific fineness range, and in that case, fibers of various finenesses may be included. If the fiber fineness is too small, when the nonwoven fabric is produced by entanglement treatment using a high-pressure fluid flow, the fibers may become entangled with the support, or the support may become clogged with the fibers. If the fiber fineness is too large, the pattern may become unclear.

The fiber length of the fibers is not limited as long as a pattern is formed in both or either of the first and second intertwining parts, and is selected according to the manufacturing conditions of the nonwoven fabric. The fiber length of the fibers is, for example, 10 mm or more and 100 mm or less. If the fiber length is outside this range, it may be difficult to produce a fiber web using, for example, a carding machine. In addition, in a low basis weight nonwoven fabric, if the fiber length exceeds 100 mm, the number of fibers constituting the nonwoven fabric is reduced, so that the texture of the nonwoven fabric may not be stable or the required strength of the nonwoven fabric may not be obtained. In addition, if the fiber length is too small, the strength of the nonwoven fabric may decrease, and if the fiber length is too large, the pattern may not be clear. The fiber length is more preferably 25 mm or more and 90 mm or less, even more preferably 32 mm or more and 70 mm or less, and particularly preferably 38 mm or more and 65 mm or less. Alternatively, if the nonwoven fabric is manufactured by a method that includes producing a fiber web by an air-laying method or a wet-laying method, the fiber length may be, for example, 2 mm or more and 20 mm or less.

[Nonwoven fabric form]
The nonwoven fabric may have a single layer structure or a laminate structure. The nonwoven fabric may be formed from a web selected from a card web such as a parallel web, a cross web, a semi-random web, and a random web, an air-laid web, a wet-laid paper web, a melt-blown web, and a spunbond web. When the cellulosic fibers are used as all or part of the constituent fibers, a web selected from a card web, an air-laid web, and a wet-laid paper web may be produced. When a nonwoven fabric is produced using these fiber webs containing cellulosic fibers, particularly by an entanglement treatment using a high-pressure fluid flow, the fibers are easily entangled with each other, and the entangled state is well maintained even after the entanglement treatment, resulting in a nonwoven fabric. This makes it easy to form a clear pattern on the nonwoven fabric, and the fibers are well entangled with each other, thereby suppressing fluffing of the nonwoven fabric.

In addition, the mechanical strength of the nonwoven fabric can be improved by forming the nonwoven fabric into a laminated structure including an air-laid web, a wet-laid paper web, a melt-blown web, or a spunbond web.

[Physical properties of nonwoven fabric]
The physical properties of the nonwoven fabric of this embodiment will be described below by way of example. It should be noted that the nonwoven fabric of this embodiment is not limited to those having the following physical properties because the physical properties of the nonwoven fabric vary depending on the fibers constituting the nonwoven fabric, the basis weight of the nonwoven fabric, and the manufacturing conditions of the nonwoven fabric.

The thickness of the nonwoven fabric of this embodiment (under a load of 294 Pa) may be, for example, 0.50 mm or more and 1.0 mm or less, particularly 0.55 mm or more and 0.90 mm or less, and more particularly 0.60 mm or more and 0.80 mm or less.

The nonwoven fabric of this embodiment has a striped pattern formed by first and second intertwined parts, one of which has a different pattern, or one of which has no pattern and the other has a pattern. When the nonwoven fabric is viewed perpendicularly to the MD and CD directions, the amount of thickness change is significantly greater in one direction than in the other. The amount of thickness change can be determined by measuring the thickness using a microscope under a load of 40 Pa. Specifically, the thickness measurement using a microscope is performed as follows.

<Method of measuring thickness using a microscope>
The nonwoven fabric is cut with a sharp blade so as to obtain a rectangular sample with each side parallel to the MD and CD directions. The cut nonwoven fabric is placed on a smooth table, a load of 40 Pa is applied, and a microscope is placed directly beside the cut surface obtained by cutting in a direction perpendicular to the MD direction, and the distance (thickness) in the thickness direction is measured in the part where the fibers exist. Measurements are performed at six points, and the average value is taken as the average thickness in the MD direction. Similarly, a microscope is placed directly beside the cut surface obtained by cutting in a direction perpendicular to the CD direction, and the distance (thickness) in the thickness direction is measured in the part where the fibers exist. Measurements are performed at six points, and the average value is taken as the average thickness in the CD direction.

When two intertwined portions are arranged in a striped pattern, as in the nonwoven fabric of this embodiment, depending on the cutting direction, the cut surface may be a cut surface of only the first intertwined portion or only the second intertwined portion (a cut surface consisting of either one of the intertwined portions). In that case, the thickness is measured at the cut surface of only one of the intertwined portions.

When the thickness of the nonwoven fabric of this embodiment is determined by the above method, the average thickness in the MD direction may be, for example, 0.50 mm or more and 1.5 mm or less, particularly 0.60 mm or more and 1.0 mm or less, and more particularly 0.65 mm or more and 0.90 mm or less. The average thickness in the CD direction may be, for example, 0.50 mm or more and 1.5 mm or less, particularly 0.60 mm or more and 1.0 mm or less, and more particularly 0.65 mm or more and 0.90 mm or less.

In addition, in the nonwoven fabric of this embodiment, the coefficient of variation of the thickness in the CD direction of the nonwoven fabric may be 0.09 or more, particularly 0.12 or more, more particularly 0.15 or more. The upper limit of the coefficient of variation of the thickness of the nonwoven fabric in the CD direction may be, for example, 0.30. When only one intertwined part is observed on the cut surface (when the cut surface consists of one intertwined part), the standard deviation σ is calculated from the data obtained by measuring the thickness at six points, and the coefficient of variation is calculated from the following formula. When multiple types of intertwined parts are observed on the cut surface (when the cut surface consists of multiple intertwined parts), the thickness is measured at six points in each intertwined part, the standard deviation is calculated from the measurement data of (6 x types of intertwined parts), and the coefficient of variation is calculated from the following formula.
Coefficient of variation of thickness = standard deviation σ / average thickness

The coefficient of variation of the thickness of the nonwoven fabric indicates the variation in the thickness of the nonwoven fabric in a given direction, and the larger this coefficient is, the more firmly the unevenness is formed along that direction. If the coefficient of variation of the thickness of the nonwoven fabric is too small, the unevenness will be small and wiping performance may be poor when used as a wiper, whereas if it is too large, the nonwoven fabric may get caught on the unevenness of the object being wiped, resulting in a poor usability.

The basis weight of the nonwoven fabric of this embodiment is not particularly limited and may be appropriately selected depending on the application. For example, when the nonwoven fabric of this embodiment is used as a wiper, the basis weight may be 30 g/m ² or more and 80 g/m ² or less, particularly 35 g/m ² to 75 g/m ² , and more particularly 40 g/m ² to 70 g/m ^2. Alternatively, when the nonwoven fabric of this embodiment is used as a sanitary product, the basis weight may be 20 g/m ² to 70 g/m ² , particularly 25 g/m ² to 65 g/m ² , and more particularly 30 g/m ² to 60 g/m ^2. If the basis weight is too large, a pattern may be formed only on one side, and the effect of the pattern may be expressed only on one side. If the basis weight is too small, a clear pattern may not be formed, and the effect of the pattern may not be exerted.

The nonwoven fabric of this embodiment may have a tensile strength of 25 N/5 cm to 140 N/5 cm, particularly 30 N/5 cm to 100 N/5 cm, more particularly 35 N/5 cm to 80 N/5 cm, in a direction perpendicular to the direction in which the first intertwined portion extends. The nonwoven fabric may also have a tensile strength of 3.0 N/5 cm to 25 N/5 cm, particularly 3.5 N/5 cm to 23 N/5 cm, more particularly 4.0 N/5 cm to 20 N/5 cm, and even more particularly 5.0 N/5 cm to 15 N/5 cm, in a direction parallel to the direction in which the first intertwined portion extends. If the tensile strength in the direction perpendicular to the direction in which the first intertwined portion extends and/or the tensile strength in the direction parallel to the direction in which the first intertwined portion extends is too high, the texture may deteriorate, and if it is too low, the shape stability of the nonwoven fabric may be insufficient.

The nonwoven fabric of this embodiment may have an elongation rate of 20% to 50%, particularly 23% to 47%, more particularly 26% to 43%, in the direction perpendicular to the direction in which the first intertwined portions extend, and an elongation rate of 70% to 140%, particularly 75% to 125%, more particularly 80% to 110%, in the direction parallel to the direction in which the first intertwined portions extend. If the elongation rate in the direction perpendicular to the direction in which the first intertwined portions extend and/or the elongation rate in the direction parallel to the direction in which the first intertwined portions extend are too high, the nonwoven fabric may be prone to elongation and may not have sufficient shape stability, whereas if the elongation rate is too low, the nonwoven fabric may not elongate when an external force is applied to it, and may immediately break, again resulting in insufficient shape stability.

In addition, the nonwoven fabric of this embodiment may have a 10% elongation stress of 4.5 N/5 cm to 110 N/5 cm, particularly 5.5 N/5 cm to 100 N/5 cm, more particularly 8.0 N/5 cm to 50 N/5 cm, and even more particularly 12 N/5 cm to 25 N/5 cm, in a direction perpendicular to the direction in which the first intertwined portion extends. In addition, the nonwoven fabric may have a 10% elongation stress of 0.6 N/5 cm to 3.0 N/5 cm, particularly 0.7 N/5 cm to 2.5 N/5 cm, and more particularly 0.8 N/5 cm to 2.0 N/5 cm, in a direction parallel to the direction in which the first intertwined portion extends. If the stress at 10% elongation in the direction perpendicular to the extension direction of the first intertwined portions and/or the stress at 10% elongation in the direction parallel to the extension direction of the first intertwined portions is too high, the fiber freedom of the nonwoven fabric is small, making it difficult for the nonwoven fabric to conform to the shape of the object when it comes into contact with the object, which may result in a small contact area between the object and the nonwoven fabric, and if it is too low, the shape stability of the nonwoven fabric will be insufficient.

The nonwoven fabric of this embodiment may have a stress at 20% elongation of 15 N/5 cm to 140 N/5 cm, particularly 17 N/5 cm to 100 N/5 cm, more particularly 20 N/5 cm to 80 N/5 cm, in a direction perpendicular to the direction in which the first intertwined portion extends. The nonwoven fabric may have a stress at 20% elongation of 1.0 N/5 cm to 3.5 N/5 cm, particularly 1.2 N/5 cm to 3.0 N/5 cm, more particularly 1.4 N/5 cm to 2.5 N/5 cm, in a direction parallel to the direction in which the first intertwined portion extends. If the stress at 20% elongation in the direction perpendicular to the extension direction of the first intertwined portions and/or the stress at 20% elongation in the direction parallel to the extension direction of the first intertwined portions is too high, the fiber freedom of the nonwoven fabric is small, making it difficult for the nonwoven fabric to conform to the shape of the object when it comes into contact with the object, which may result in a small contact area between the object and the nonwoven fabric, and if it is too low, the shape stability of the nonwoven fabric may be insufficient.

The nonwoven fabric of this embodiment has a lower water absorbency and tends to be less susceptible to liquid diffusion than a nonwoven fabric having the same pattern formed over the entire surface. Specifically, when the water absorbency of the nonwoven fabric of this embodiment is measured by the Byreck method in accordance with JIS L 1907 7.1.2, the nonwoven fabric may have a water absorbency of, for example, 1 mm to 90 mm in the CD direction and 1 mm to 70 mm in the MD direction. In addition, in the nonwoven fabric of this embodiment, when the water absorbency in the MD direction is A (mm) and the water absorbency in the CD direction is B (mm), the area of the pseudo-diffusion ellipse measured by A x B x π may be, for example, 146 cm ² or less, particularly 144 cm ² or less, more particularly 142 cm ² or less. The lower limit of the area of the pseudo-diffusion ellipse is, for example, 0.03 cm ² , particularly 0.3 cm ² , more particularly 0.8 cm ² . The reason why the nonwoven fabric of this embodiment exhibits the above-mentioned water absorption properties is believed to be that when water is absorbed, the progress of water is hindered by the recesses and pores formed in the first entangled parts and the second entangled parts.

(Embodiment 2: Method for producing the nonwoven fabric of embodiment 1)
As embodiment 2, a method for producing the nonwoven fabric of embodiment 1 will be described. The nonwoven fabric of embodiment 1 can be produced, for example, by
Producing a fibrous web;
placing the fibrous web on a support and subjecting the fibrous web to an entanglement treatment using a high-pressure fluid flow;
In the entanglement treatment, it is assumed that the fiber web has a first section and a second section extending along the CD direction in a striped pattern,
The entanglement treatment is performed under different treatment conditions when the first section of the fiber web is subjected to the entanglement treatment and when the second section of the fiber web is subjected to the entanglement treatment, so that the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, have different patterns, or one of the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, has no pattern and the other has a pattern.
It can be produced by a production method.

This manufacturing method corresponds to a method in which a high-pressure fluid flow is sprayed onto a fiber web to entangle the fibers and integrate them. The high-pressure fluid is, for example, a high-pressure gas such as compressed air, or a high-pressure liquid such as high-pressure water. In the manufacture of nonwoven fabrics, a hydroentanglement process using high-pressure water as the high-pressure fluid is often used, and in this embodiment, the hydroentanglement process is preferably used from the viewpoint of ease of implementation. Below, a manufacturing method in which a high-pressure water flow (hereinafter also simply referred to as "water flow") is used as the high-pressure fluid flow will be described.

In this manufacturing method, when the surface of the fiber web to be subjected to the hydroentanglement treatment is viewed, it is assumed that the fiber web has a first section and a second section extending along the CD direction in a striped pattern, and the two sections are subjected to the hydroentanglement treatment under different treatment conditions. The conditions for the hydroentanglement treatment include, for example, the orifice hole size, the spacing between the orifices, the number of water jets in the MD direction, the water pressure, the amount of water, the transport speed of the fiber web, and the structure of the surface of the support that transports the fiber web during the hydroentanglement treatment that comes into contact with the fiber web. The hydroentanglement treatment in the two sections is performed under different treatment conditions by making at least one of these different.

The conditions for the hydroentanglement treatment of the two sections are selected so that the first entangled portion formed by entanglement of the first section and the second entangled portion formed by entanglement of the second section have different patterns, or one of the first entangled portion formed by entanglement of the first section and the second entangled portion formed by entanglement of the second section has no pattern and the other has a pattern. The conditions for making the two entangled portions different from each other in order to obtain such two entangled portions after the entanglement treatment may be, for example, the structure of the support surface.

For example, a single support (hereinafter, for convenience, referred to as a "striped pattern forming support") on which two types of weaves are regularly and repeatedly formed along the MD direction may be used as the support. By simultaneously spraying water streams on the first and second sections of the fiber web on this support (i.e., by not changing the conditions for spraying the water streams between the two sections), the first and second entangled portions of the nonwoven fabric described as embodiment 1 can be formed. The first entangled portion is formed by rearranging the fibers so as to have a pattern determined by one of the two types of weaves constituting the striped pattern forming support (for convenience, referred to as "weave structure A"), and becomes a linear portion extending in the CD direction. Similarly, the second entangled portion is formed by rearranging the fibers so as to have a pattern determined by the other of the two types of weaves constituting the striped pattern forming support (for convenience, referred to as "weave structure B").

In the striped pattern forming support, for example, weave structure A and weave structure B are arranged in the order A-B-A-B... along the MD direction. Therefore, the first intertwined portion and the second intertwined portion formed by the weave structures A and B of this support are also formed in the order 1-2-1-2... along the MD direction. Therefore, the nonwoven fabric produced by this method has a striped pattern in which the first intertwined portion and the second intertwined portion extend along the CD direction.

The striped pattern forming support may be, for example, woven from filaments having a diameter of 0.5 mm to 1.0 mm, with twill weave sections as weave structure A and plain weave sections as weave structure B alternately formed along the MD direction. With such a support, a first intertwined section having a diagonal line pattern is formed in the twill weave section, and a second intertwined section with staggered openings is formed in the plain weave section. In the support, weave structure A and weave structure B may be woven using filaments of different thicknesses as weft yarns.

In the striped pattern forming support, the MD dimensions of the weaves A and B determine the MD dimensions of the first and second intertwined parts in the resulting nonwoven fabric (i.e., the dimensions of the first and second intertwined parts in the direction perpendicular to the direction in which the first and second intertwined parts extend). In this embodiment, the MD dimension of the weave A may be 2 mm or more and 200 mm or less, particularly 3 mm or more and 100 mm or less, more particularly 5 mm or more and 50 mm or less, even more particularly 7 mm or more and 30 mm or less, and even more particularly 10 mm or more and 25 mm or less. Similarly, the MD dimension of the weave B may be 2 mm or more and 200 mm or less, particularly 3 mm or more and 100 mm or less, more particularly 5 mm or more and 50 mm or less, even more particularly 7 mm or more and 30 mm or less, and even more particularly 10 mm or more and 25 mm or less. The MD dimension of the weave A may be the same as or different from the MD dimension of the weave B. Furthermore, in one support, there may be multiple weave structures A with different dimensions in the MD direction, and/or there may be multiple weave structures B with different dimensions in the MD direction.

When weave structure A is a twill weave, the shape of the diagonal pattern in the first intertwined portion changes depending on the fiber diameter of the monofilament, the warp density, and the weft density, as well as the number of warps floating above the weft and/or the number of warps sinking below the weft in the twill weave. A twill weave is constructed such that the warps floating above the weft are either adjacent or not adjacent, and when the floating warp portions are connected with straight lines, if a straight line extending diagonally including all the floating portions can be drawn, a first intertwined portion with a diagonal pattern is obtained. If such a straight line cannot be drawn, a first intertwined portion with a mottled pattern is obtained.

When the weave structure B is a plain weave section, the size of the openings formed in the second intertwined section varies depending on the fiber diameter of the monofilaments that make up the structure, and the area of the openings tends to increase as the fiber diameter of the monofilaments increases. In addition, the spacing between the openings varies depending on the weft and warp densities of the plain weave section, and the spacing between the openings tends to decrease as the weft and/or warp densities increase.

In the striped pattern forming support, weave structures A and B may both be plain weave structures. In that case, the two weave structures can be made different from each other by changing the thickness of the weft threads and/or the density of the weft threads. Also, weave structures A and B may both be twill weave structures. In that case, the two weave structures can be made different from each other by using one of the methods selected from changing the number of warp threads that float above the weft threads, changing the number of warp threads that sink below the weft threads, changing the thickness of the weft threads, etc.

If weave structure B is a fine plain weave portion (e.g., 80 mesh or more and 100 mesh or less), a second intertwined portion without a pattern is formed corresponding to the weave. In this case, weave structure A may be a weave in which a pattern can be formed, such as a twill weave portion, or a plain weave portion made of thick filaments.

Alternatively, the conditions of the hydroentanglement treatment can be made different between the two sections by placing a plate (hereinafter, "intervening plate") between the fiber web and the nozzle, which is shaped so that the water flow does not hit the fiber web in a portion corresponding to one of the sections, and moving it in accordance with the traveling speed of the fiber web. Such an intervening plate may be a ladder-shaped plate with rectangular openings provided at regular intervals in the MD direction (the traveling direction of the fiber web). In the portion where the water flow is prevented from being sprayed by the intervening plate, entanglement does not progress in the fiber web, resulting in a patternless state, while in the portion located at the opening of the intervening plate where the water flow is sprayed, entanglement progresses in the fiber web and a pattern corresponding to the weave structure of the support is formed. Therefore, by using such an intervening plate, a nonwoven fabric can be obtained in which one entangled portion is patternless and the other has a pattern.

Alternatively, the conditions of the hydroentanglement treatment can be made different between the two sections by using two types of supports and the above-mentioned intervening plate. Specifically, first, a fiber web is placed on one support, and with the above-mentioned ladder-shaped intervening plate placed between the web and the nozzle, a water stream is sprayed onto the fiber web to form a pattern, for example, only in the first section. Then, the fiber web with the pattern formed in the first section is placed on another support, and the intervening plate is placed so that the opening of the intervening plate is located in the second section, and a water stream is sprayed onto the fiber web to form a pattern in the second section that corresponds to the weave of the other support. This method can also form a first intervening portion and a second intervening portion having different patterns.

In this embodiment, the fiber web may be subjected to a process (overall entanglement process) in which the constituent fibers are entangled overall, and then to a hydroentanglement process in which the hydroentanglement process conditions are different between the two sections. The overall entanglement process may be performed under the same process conditions over the entire fiber web. The overall entanglement process may also be performed so that the fiber web after the entanglement process has no pattern, i.e., is patternless. By entangling the fibers to a certain degree in advance by the overall entanglement process, it becomes easier to create a pattern in the subsequent entanglement process.

The overall entanglement process is carried out by placing the fiber web on a support and spraying a columnar water stream onto it. For example, the support is preferably a plain weave support of 80 mesh or more and 100 mesh or less. Such a support makes it possible to entangle the fibers of the fiber web without forming a pattern on the fiber web and with good texture.

The fiber web can be produced by a known method. The form of the fiber web may be any form selected from, for example, parallel webs, cross webs, card webs such as semi-random webs and random webs, air-laid webs, and wet-laid paper webs. In this embodiment, a card web is preferably used because it is easy to obtain a thickness and to form unevenness.

The overall entanglement treatment may be carried out by spraying a water stream with a water pressure of 1 MPa to 15 MPa from a nozzle having orifices with a hole diameter of 0.05 mm or more and 0.5 mm or less spaced at intervals of 0.3 mm or more and 1.5 mm or less onto the front and back surfaces of the fiber web 1 to 5 times each. The water pressure is preferably 1 MPa or more and 10 MPa or less, and more preferably 1 MPa or more and 7 MPa or less.

The entanglement treatment for the first and second sections (hereinafter, "section entanglement treatment") may be performed by spraying a water stream with a water pressure of 1 MPa or more and 15 MPa or less from a nozzle having orifices with a hole diameter of 0.05 mm or more and 0.5 mm or less arranged at intervals of 0.3 mm or more and 1.5 mm or less onto the front and back surfaces of the fiber web 1 to 5 times. The water pressure is preferably 1 MPa or more and 10 MPa or less, and more preferably 1 MPa or more and 7 MPa or less. In this embodiment, when the entire entanglement treatment is not performed and only the section entanglement treatment is performed, the water pressure may be set higher than when the entire entanglement treatment is performed so that the desired entanglement state is achieved. In this embodiment, when the section entanglement treatment is performed twice using two types of supports, the water pressure of the water stream sprayed onto each section may be within the above range.

The first and second entangled portions are formed by subjecting the first and second sections to a hydroentanglement process, and the fiber web is then subjected to a drying process to obtain the nonwoven fabric of embodiment 1.

When the fiber web contains adhesive fibers, a bonding process may be performed simultaneously with or after the drying process, so that the fibers are bonded together in the resulting nonwoven fabric. The bonding process may be a thermal bonding process, or bonding by electron beam irradiation or ultrasonic welding. By using a heat treatment, the adhesive fibers (e.g., low melting point components of the composite fibers) melt or soften by heating during the heat treatment, and the fibers constituting the fiber web can be bonded together. By using a heat treatment, the drying process can be performed simultaneously.

The heat treatment is, for example, a hot air processing treatment in which hot air is blown, a heat roll processing (heat embossing roll processing), or a heat treatment using infrared rays. The hot air processing treatment may be carried out using a device that blows hot air at a predetermined temperature onto the fiber web, for example, a hot air penetration type heat treatment machine or a hot air blowing type heat treatment machine.

The heat treatment temperature (e.g., the temperature of the hot air) may be the temperature at which the component that constitutes the adhesive fiber and functions as an adhesive component softens or melts. For example, the heat treatment temperature may be a temperature equal to or higher than the melting point of the component. For example, when the adhesive fiber contains polyethylene as a component and polyethylene is used as the adhesive component, the heat treatment temperature may be 130°C to 150°C.

In the above, a striped pattern forming support in which two different weaves are regularly and repeatedly formed in the MD direction is exemplified. In a modified version of this embodiment, a support in which three or more different weaves (e.g., weaves A, B, and C) are repeatedly formed in the MD direction, for example, in the order A-B-C- or A-B-A-C-, may be used. When this support is used, a nonwoven fabric in which a third entangled portion is formed corresponding to weave C is obtained. In addition, in order to form three types of entangled portions, for example, three types of supports may be used, and the intervening plate may be shaped so that the water flow is sprayed only on the portion corresponding to one of the three sections, and the hydroentanglement treatment may be performed by the method described above.

(Embodiment 3: Uses of the nonwoven fabric of embodiment 1)
As a third embodiment, a product using the nonwoven fabric of the first embodiment will be described.
The nonwoven fabric of the first embodiment may be used as a wiper alone or together with other nonwoven fabrics or sheets. The nonwoven fabric of the first embodiment has a tensile strength S1 in the direction in which each linear portion constituting the striped pattern extends, which is smaller than the tensile strength S2 in the direction perpendicular to the direction in which each linear portion constituting the striped pattern extends. Therefore, even if this nonwoven fabric is placed on an object having dirt and is rubbed by reciprocating in a direction perpendicular to the direction in which the first and second intertwined portions corresponding to each linear portion extend, the nonwoven fabric is unlikely to twist, and the dirt on the object can be effectively wiped off by the striped pattern.

When the rate of gradation change during wiping of the nonwoven fabric of embodiment 1 is measured by the following method, the rate of gradation change T1 during wiping in the direction in which the first intertwined portions extend and the rate of gradation change T2 during wiping in a direction perpendicular to the direction in which the first intertwined portions extend may satisfy T2/T1>1.0.
(Method for measuring the rate of change in gradation when wiping)
A transparent acrylic plate (thickness 3 mm, product number: KAC9143-1S, manufactured by Hikari Corporation) with a mark (a square frame with sides of 1.5 cm drawn with a pen) is placed on the opposite side of the mark with three drops (0.05 ml per drop) of artificial dirt (a mixture of blue acrylic paint (product name: acrylic paint (blue), manufactured by Daiso Industries Co., Ltd.), ethanol (product name: Wako First Grade Ethanol (99.5), manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) and distilled water (blue acrylic paint: ethanol: distilled water = 10: 50: 40 (mass ratio))) and spread evenly over an area larger than the area of the mark, and air-dried for 60 minutes, and the grayscale gradation A within the mark (excluding the area of the square frame drawn with a pen) after air-drying is measured. Image analysis processing software (software name: Image J) is used for gradation measurement. Another acrylic plate is placed on the side with the artificial stain to protect the stain, and image data is captured with a scanner (product name: Docu Centre VIIC4473, manufactured by Fuji Xerox Co., Ltd.). The captured image data is split into RGB channels (Split Channels), and the average value of the gradation within the mark for only the red component is confirmed using a histogram, and this is designated as grayscale gradation A.

The artificial dirt applied to the acrylic plate is attached to a plate-shaped jig (wiping area 6 cm x 6 cm) of a sample nonwoven fabric (100 parts by weight of nonwoven fabric is impregnated with 300 parts by weight of distilled water) of 10 cm in the MD direction and 6 cm in the CD direction, and while applying a pressure of 510 Pa, it is moved back and forth twice in a specified direction at a speed of 10 mm/sec and a movement distance of 100 mm. After wiping, the grayscale gradation B of the artificial dirt remaining on the acrylic plate is obtained in the same manner as for gradation A, and the gradation change rate T (%) is calculated according to the following formula.

T1 and T2 may particularly satisfy T2/T1≧1.05, more particularly T2/T1≧1.10. The upper limit of T2/T1 may be, for example, 3.0, particularly 2.5, more particularly 2.0.

Satisfying T2/T1>1.0 means that the wiping ability is higher when the wiping direction is perpendicular to the extension direction of the first intertwined portion than when the wiping direction is the extension direction of the first intertwined portion. Therefore, when the extension direction of the first intertwined portion is the CD direction of the nonwoven fabric, the wiping ability is higher when the wiping direction is the MD direction than when the wiping direction is the CD direction. Such wiping ability could not be obtained with conventional striped nonwoven fabrics in which each linear portion extends in the MD direction.

When the nonwoven fabric of embodiment 1 satisfies T2/T1>1.0 and is used as a wiper, the user can easily recognize the wiping direction that provides the best wiping effect. In other words, if the relationship between the striped pattern and the preferred moving direction of the wiper is indicated on the package or the like, combined with the clear striped pattern formed on the wiper itself, the user will not mistake the moving direction of the wiper and can wipe in the correct direction.

Alternatively, the nonwoven fabric of this embodiment may be used in sanitary products such as sanitary napkins, disposable diapers for babies, and disposable diapers for adults. As described above, the nonwoven fabric of this embodiment has unique water absorption properties, and absorbed liquid is less likely to spread in the nonwoven fabric of this embodiment. Therefore, the nonwoven fabric of this embodiment may be used as a member, particularly a surface material, in sanitary products where it is required to suppress the spread of blood or excrement. Alternatively, the nonwoven fabric of this embodiment may be used in wet towels, face masks, sanitary masks, filters, poultices, etc.

The present embodiment will now be described with reference to examples.
The following fibers were prepared for use in the examples and comparative examples.
Rayon (cellulosic fiber): viscose rayon fiber having a fineness of 1.7 dtex and a fiber length of 40 mm (Corona CD (trade name) manufactured by Daiwabo Rayon Co., Ltd.).
PET: A single fiber made of polyethylene terephthalate having a fineness of 1.45 dtex and a fiber length of 38 mm (product name: Tetoron T403, manufactured by Toray Industries, Inc.).
PP/PE: A concentric core-sheath type composite fiber (NBF(H) (product name) manufactured by Daiwa Boseki Co., Ltd.) having a core of polypropylene and a sheath of high-density polyethylene (melting point: approximately 133°C) with a composite ratio (core:sheath) of 37:63 (volume ratio), a fineness of 1.7 dtex, and a fiber length of 51 mm.

In the production of the nonwoven fabrics of the Examples and Comparative Examples, the supports used in the second hydroentanglement treatment are shown below.
Support 1: Warp thread diameter 0.81 mm and 0.41 mm (two types of filaments arranged alternately), weft thread diameter 0.72 mm, warp thread density 25 threads/inch, weft thread density 17 threads/inch, plain weave fabric
Support 2: warp thread diameter 0.7 mm, weft thread diameter 0.9 mm, warp thread density
41 threads/inch, weft density 16 threads/inch, 3/1 herringbone weave
Support 3: A fabric having warp thread diameters of 0.88 mm and 0.57 mm (two types of filaments arranged alternately), weft thread diameters of 0.45 mm (plain weave portion) and 0.9 mm (twill weave portion), warp thread density of 30 threads/inch, weft thread density of 17 threads/inch, plain weave and 2/2 twill weave alternately in the MD direction, the dimension of one plain weave portion in the MD direction being 24 mm, and the dimension of one 2/2 twill portion in the MD direction being 11 mm. Support 4: A fabric having warp thread diameters of 0.88 mm and 0.57 mm (two types of filaments arranged alternately), weft thread diameters of 0.45 mm (plain weave portion) and 0.8 mm (twill weave portion), warp thread density of 30 threads/inch, weft thread density of 25 threads/inch, plain weave and 1/7 twill weave alternately in the MD direction, the dimension of one plain weave portion in the MD direction being 24 mm, and the dimension of one 1/7 twill portion in the MD direction being 11 mm.

(Test 1)
<Production of Nonwoven Fabric 1-A: Comparative Example>
A fiber web was produced by mixing 80% by weight of rayon and 20% by weight of PP/PE using a parallel carding machine. The basis weight of this fiber web was about 40 g/ ^m2 .
[First hydroentanglement treatment (total entanglement treatment)]
The above-mentioned fiber web was placed on a plain weave net with a warp diameter of 0.132 mm, a weft diameter of 0.132 mm, and a mesh number of 90 meshes. While the fiber web was moving at a speed of 4 m/min, a columnar water stream with a water pressure of 1.0 MPa was sprayed onto the front surface of the fiber web, and then a columnar water stream with a water pressure of 1.5 MPa was sprayed onto the back surface of the fiber web. A nozzle with orifices with a hole diameter of 0.12 mm and spaced 0.6 mm apart was used to spray the water stream. The distance between the surface of the fiber web and the orifice was 15 mm.

[Second hydroentanglement treatment]
The fiber web after the first hydroentanglement treatment was placed on a support 1, and while the fiber web was moving at a speed of 4 m/min, a columnar water stream was sprayed onto the back surface of the fiber web at a water pressure of 1.5 MPa. The same nozzle as that used in the first hydroentanglement treatment was used to spray the water stream. The second hydroentanglement treatment formed a pattern in which the openings were regularly arranged in a staggered pattern over the entire nonwoven fabric. The area per opening was 0.4 ^mm2 , the shortest distance between the centers of adjacent openings was 1.8 mm, and the proportion of the openings on the surface of the nonwoven fabric was 13%.

[Heat treatment]
The nonwoven fabric after the second hydroentanglement treatment was heated at 135°C for about 5 seconds using a hot air penetration type heat treatment machine to carry out a drying treatment, and at the same time, the fibers were thermally bonded to each other by the PP/PE sheath component to obtain nonwoven fabric 1-A.

<Production of Nonwoven Fabric 1-B: Comparative Example>
Nonwoven fabric 1-B was obtained in the same manner as in the production of nonwoven fabric 1-A, except that support 2 was used in the second hydroentanglement treatment.
Nonwoven fabric 1-B had a herringbone pattern formed over the entire surface.

<Production of Nonwoven Fabric 1-C: Example>
Nonwoven fabric 1-C was obtained in the same manner as in the production of nonwoven fabric 1-A, except that support 3 was used in the second hydroentanglement treatment and the second hydroentanglement treatment was carried out as a section entanglement treatment.
In nonwoven fabric 1-C, a first intertwined portion extending along the CD direction of the nonwoven fabric, which was a diagonal line pattern portion, and a second intertwined portion, which was a pattern portion in which the openings were arranged in a staggered pattern, were alternately repeated in the MD direction to form a striped pattern. The dimension of the first intertwined portion (diagonal line pattern portion) in the MD direction was 24 mm, and the dimension of the second intertwined portion (open hole pattern portion) in the MD direction was 11 mm. The acute angle formed by the diagonal line of the first intertwined portion and the CD direction was 57 degrees. In the second intertwined portion, the area per opening was 0.04 ^mm2 , the shortest distance between the centers of adjacent openings was 1.5 mm, and the proportion of the openings in the second intertwined portion was 1.6%.

<Production of Nonwoven Fabric 1-D: Comparative Example>
Nonwoven fabric 1-D was obtained in the same manner as in the production of nonwoven fabric 1-A, except that the second hydroentanglement treatment was carried out in the following manner.
[Hydroentanglement process 2]
The fiber web after the first hydroentanglement treatment was placed on the support 1, and while the fiber web was moving at a speed of 4 m/min, a columnar water flow with a water pressure of 1.5 MPa was sprayed onto the back surface of the fiber web. The same nozzle as that used in the first hydroentanglement treatment was used to spray the water flow, but a nozzle in which some of the orifices were blocked so that the water flow was not sprayed from the orifices was used. Specifically, a part of the orifice was blocked so that the part P1 with the blocked orifice and the part P2 with the unblocked orifice were 10 mm (P1) and 20 mm (P2) long in the CD direction, respectively, and P1 and P2 were alternately arranged in the CD direction. By using this nozzle, a pattern part in which openings extending along the MD direction were regularly arranged and a plain part extending along the MD direction were alternately formed in the CD direction on the fiber web.

Then, the fiber web was placed on a support 2, and while the fiber web was moving at a speed of 4 m/min, a columnar water flow with a water pressure of 1.5 MPa was sprayed onto the back surface of the fiber web to obtain a nonwoven fabric. The same nozzle as that used in the first water flow entanglement treatment was used to spray the water flow, but a nozzle in which some of the orifices were blocked to prevent the water flow from being sprayed from those orifices was used. Specifically, some of the orifices were blocked so that the blocked orifice portion Q1 and the unblocked orifice portion Q2 were 20 mm (Q1) and 10 mm (Q2) long in the CD direction, respectively, and Q1 and Q2 were alternately arranged in the CD direction. This nozzle was used to allow the water flow to hit the previously formed plain portion.

By carrying out the second hydroentanglement treatment according to the above procedure, in nonwoven fabric 1-D, oblique line pattern parts extending along the MD direction of the nonwoven fabric and pattern parts (open hole pattern parts) in which the openings are regularly arranged in a staggered pattern were formed alternately along the CD direction. The dimension of the oblique line pattern part in the CD direction was 10 mm, and the dimension of the open hole pattern part in the CD direction was 20 mm. In the open hole pattern part, the area per opening was 0.4 ^mm2 , the shortest distance between the centers of adjacent openings was 1.8 mm, and the proportion of the open holes in the open hole pattern part was 13%.

<Production of Nonwoven Fabric 1-E: Example>
Nonwoven fabric 1-E was obtained in the same manner as in the production of nonwoven fabric 1-A, except that support 4 was used in the second hydroentanglement treatment and the second hydroentanglement treatment was carried out as a section entanglement treatment.
In nonwoven fabric 1-E, a first intertwined portion extending along the CD direction of the nonwoven fabric, which was a diagonal line pattern portion, and a second intertwined portion, which was a pattern portion in which the openings were arranged in a staggered pattern, were alternately repeated in the MD direction to form a striped pattern. The dimension of the first intertwined portion (diagonal line pattern portion) in the MD direction was 14 mm, and the dimension of the second intertwined portion (open hole pattern portion) in the MD direction was 9 mm. The acute angle formed by the diagonal line of the first intertwined portion and the CD direction was 17 degrees. In the second intertwined portion, the area per opening was 0.04 ^mm2 , the shortest distance between the centers of adjacent openings was 1.5 mm, and the proportion of the openings in the second intertwined portion was 1.1%.

(Test 2)
Nonwoven fabrics 2-A to 2-D were obtained in the same manner as in the production of nonwoven fabrics 1-A to 1-D produced in Test 1, except that 40% by weight of rayon, 40% by weight of PET, and 20% by weight of PP/PE were mixed and a fiber web was produced using a parallel carding machine.

(Test 3)
Nonwoven fabrics 3-A to 3-D were obtained in the same manner as in the production of nonwoven fabrics 1-A to 1-D produced in Test 1, except that 80% by mass of PET and 20% by mass of PP/PE were mixed and a fiber web was produced using a parallel carding machine.

The nonwoven fabrics produced in Tests 1 to 3 were evaluated for wiping test (gradation change rate when wiping), thickness, thickness variation coefficient, water absorption properties, and runoff using the following procedure. In addition, of the nonwoven fabrics produced in Tests 1 to 3, nonwoven fabrics 1-A to 1-D, nonwoven fabrics 2-A to 2-D, and nonwoven fabrics 3-A to 3-D were evaluated for tensile strength, elongation, and stress at 10% and 20% elongation using the following procedure. The evaluation results are shown in Tables 1 and 2.

<Rate of change in gradation when wiping>
A transparent acrylic plate (thickness 3 mm, product number: KAC9143-1S, manufactured by Hikari Corporation) with a mark (a square frame with sides of 1.5 cm drawn with a pen) is placed on the opposite side of the mark with three drops (0.05 ml per drop) of artificial dirt (a mixture of blue acrylic paint (product name: acrylic paint (blue), manufactured by Daiso Industries Co., Ltd.), ethanol (product name: Wako First Grade Ethanol (99.5), manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) and distilled water (blue acrylic paint: ethanol: distilled water = 10: 50: 40 (mass ratio))) and spread evenly over an area larger than the area of the mark, and air-dried for 60 minutes, and the grayscale gradation A within the mark (excluding the area of the square frame drawn with the pen) after air-drying is measured. Image analysis processing software (software name: Image J) is used for gradation measurement. Another acrylic plate is placed on the side with the artificial stain to protect the stain, and image data is captured with a scanner (product name: Docu Centre VIIC4473, manufactured by Fuji Xerox Co., Ltd.). The captured image data is split into RGB channels (Split Channels), and the average value of the gradation within the mark for only the red component is confirmed using a histogram, and this is designated as grayscale gradation A.

The artificial dirt applied to the acrylic plate is attached to a plate-shaped jig (wiping area 6 cm x 6 cm) of a sample nonwoven fabric (100 parts by weight of nonwoven fabric is impregnated with 300 parts by weight of distilled water) of 10 cm in the MD direction and 6 cm in the CD direction, and while applying a pressure of 510 Pa, it is moved back and forth twice in a specified direction at a speed of 10 mm/sec and a movement distance of 100 mm. After wiping, the grayscale gradation B of the artificial dirt remaining on the acrylic plate is obtained in the same manner as for gradation A, and the gradation change rate T (%) is calculated according to the following formula.

<Thickness, thickness variation coefficient>
<Method of measuring thickness using a microscope>
The nonwoven fabric is cut with a sharp blade so as to obtain a rectangular sample with each side parallel to the MD or CD direction. The cut nonwoven fabric is placed on a smooth table, a load of 40 Pa is applied, and a microscope is placed directly beside the cut surface obtained by cutting in a direction perpendicular to the MD direction, and the distance (thickness) in the thickness direction is measured in the part where the fibers exist. Measurements are performed at six points, and the average value is taken as the average thickness in the MD direction. Similarly, a microscope is placed directly beside the cut surface obtained by cutting in a direction perpendicular to the CD direction, and the distance (thickness) in the thickness direction is measured in the part where the fibers exist. Measurements are performed at six points, and the average value is taken as the average thickness in the CD direction. For nonwoven fabrics in which a plurality of intertwined parts are arranged in a striped pattern, cutting in a direction parallel to the extension direction of the linear parts is performed only at one of the intertwined parts, and the thickness is measured at the cut surface of the intertwined part.

When only one intertwined portion is observed on the cut surface (when the cut surface consists of one intertwined portion), the standard deviation σ is calculated from the data obtained by measuring the thickness at six points, and the coefficient of variation is calculated from the following formula: When multiple types of intertwined portions are observed on the cut surface (when the cut surface consists of multiple intertwined portions), the thickness is measured at six points in each intertwined portion, the standard deviation is calculated from the measurement data at (6 x types of intertwined portions), and the coefficient of variation is calculated from the following formula:
Coefficient of variation of thickness = standard deviation σ / average thickness

<Water absorption (Byreck method)>
The water absorbency was measured by the Byreck method in accordance with JIS L 1907 7.1.2, and the values were measured in both the MD and CD directions. Four nonwoven fabric sample pieces were used for each direction, and the immersion time in water was 5 minutes.
Furthermore, when the water absorbency in the MD direction is A (mm) and the water absorbency in the CD direction is B (mm), the area (mm ² ) of the pseudo-diffusion ellipse measured by A×B×π was calculated.

<Tensile strength, elongation, stress at 10% elongation, stress at 20% elongation>
According to JIS L 1913:2010 6.3, a constant-speed tension tensile tester was used to perform a tensile test under the conditions of a sample width of 50 mm, a grip distance of 10 cm, and a tensile speed of 30±2 cm/min, and the load value at break (tensile strength), elongation, and stress at 10% and 20% elongation were measured. The tensile test was performed in the machine direction (MD) and cross direction (CD) of the nonwoven fabric as the tensile direction. The evaluation results are shown as the average of the values measured for each of the three samples.

All of the nonwoven fabrics 1-C, 2-C, and 3-C have a striped pattern in which the first and second intertwined parts extend in the CD direction and the first and second intertwined parts are alternately arranged in the MD direction. As shown in Table 2, these nonwoven fabrics satisfy the relationship of tensile strength in the CD direction < strength in the MD direction. All of these nonwoven fabrics had a larger coefficient of variation in thickness in the CD direction than other nonwoven fabrics produced in the same test. In addition, these nonwoven fabrics showed a relatively high gradation change rate (wiping ability) in the MD direction, and the gradation change rate in the MD direction T2/gradation change rate in the CD direction T1 was 1.0 or more. The gradation change rate of nonwoven fabric 1-E was similar. This indicates that a nonwoven fabric having a first intertwined part and a second intertwined part extending in the CD direction exhibits high wiping ability when moved in a direction perpendicular to the CD direction.

In addition, nonwoven fabrics 1-C and 1-E had lower water absorption in the MD and CD directions and smaller pseudo-diffusion ellipse areas than nonwoven fabrics 1-A and 1-B.

None of the other nonwoven fabrics (comparative examples) produced in Tests 1 and 3 had a striped pattern in which linear portions extending in the CD direction were repeatedly arranged along the MD direction. Therefore, the wiping properties of the other nonwoven fabrics were smaller in the MD direction than those of the nonwoven fabrics of the examples, or, although there was no significant difference compared to the examples, the wiping properties in the CD direction were very low. In particular, in the nonwoven fabrics 1-D, 2-D, and 3-D, which had striped patterns in which linear portions were repeatedly arranged in the CD direction, the wiping properties in the CD direction were higher than the wiping properties in the MD direction, and the gradation change rate in the MD direction T2/gradation change rate in the CD direction T1 was less than 1. Therefore, when the nonwoven fabric of the comparative example was not fixed to a tool and, for example, was held by hand and moved in the CD direction to perform wiping, the nonwoven fabric tended to fold, making it difficult to wipe off dirt.

（態様９）
前記不織布の質量を１００質量％としたときに、前記不織布がセルロース系繊維を３０質量％以上含む、態様１～８のいずれかの不織布。
（態様１０）
前記不織布の目付が３０ｇ／ｍ^２以上８０ｇ／ｍ^２以下である、態様１～９のいずれかの不織布。
（態様１１）
態様１～１０のいずれかの不織布を含むワイパー。
（態様１２）
繊維ウェブを作製すること、
前記繊維ウェブを支持体に載置して、前記繊維ウェブに高圧流体流による交絡処理を施すこと
を含み、
前記交絡処理において、前記繊維ウェブに、ＣＤ方向に沿って延びる第１セクションおよび第２セクションが縞状に存在するものと仮想し、
前記繊維ウェブの第１セクションが交絡処理に付されるときの処理条件と、前記繊維ウェブの第２セクションが交絡処理に付されるときの処理条件とを互いに異なるものとして、交絡処理後の第１セクションである第１交絡部と交絡処理後の第２セクションである第２交絡部とが互いに異なる模様を有するか、あるいは交絡処理後の第１セクションである第１交絡部および交絡後の第２セクションである第２交絡部のいずれか一方が無模様となり、他方が模様を有するように、前記交絡処理を実施する、
不織布の製造方法。
（態様１３）
前記繊維ウェブの第１セクションの交絡処理と、前記繊維ウェブの第２セクションの交絡処理とが、繊維ウェブを一つの支持体に載置して同時に行われる、態様１２の不織布の製造方法。
（態様１４）
前記交絡処理で用いられる支持体が、ＭＤ方向に沿って二種類の織組織が規則的に繰り返し形成されているものである、態様１３の不織布の製造方法。
（態様１５）
前記交絡処理で用いられる支持体が、平織部と綾織部とがＭＤ方向に沿って交互に繰り返し形成されているものである、態様１４の不織布の製造方法。
（態様１６）
前記交絡処理を行う前に、前記繊維ウェブの全体にわたって同じ処理条件にて高圧流体流による交絡処理を施す全体交絡処理を含む、態様１２～１５のいずれかの不織布の製造方法。 The present embodiment includes the following aspects.
(Aspect 1)
A nonwoven fabric including a first entangled portion and a second entangled portion,
the first intertwined portions and the second intertwined portions are present in a striped pattern,
The second intertwined portion and the first intertwined portion have different patterns, or one of the second intertwined portion and the first intertwined portion has no pattern and the other has a pattern;
A tensile strength S1 of the nonwoven fabric in a direction in which the first entangled portions extend and a tensile strength S2 of the nonwoven fabric in a direction perpendicular to the direction in which the first entangled portions extend satisfy S1<S2.
Nonwoven fabric.
(Aspect 2)
2. The nonwoven fabric of claim 1, wherein the dimension of the first entangled portions in a direction perpendicular to the direction in which the first entangled portions extend is 2 mm or more and 200 mm or less.
(Aspect 3)
3. The nonwoven fabric of claim 1 or 2, wherein the dimension of the second entangled portions in a direction perpendicular to the direction in which the second entangled portions extend is 2 mm or more and 200 mm or less.
(Aspect 4)
The first intertwined portion has a pattern, and the pattern of the first intertwined portion is a diagonal line pattern,
The acute angle between the oblique lines of the oblique line pattern and the extension direction of the first intertwined portions is 10 degrees or more and 80 degrees or less.
The nonwoven fabric of any one of embodiments 1 to 3.
(Aspect 5)
The nonwoven fabric of any of Aspects 1 to 4, wherein the second entangled portions have a pattern, and the pattern of the second entangled portions is an open hole pattern in which open holes are regularly arranged.
(Aspect 6)
6. The nonwoven fabric of claim 5, wherein the area of one opening in the opening pattern is 0.50 ^mm2 or less.
(Aspect 7)
The nonwoven fabric of any of Aspects 1 to 6, wherein the coefficient of variation of thickness of a cut section perpendicular to the CD direction of the nonwoven fabric is 0.09 or more.
(Aspect 8)
The nonwoven fabric of any of Aspects 1 to 7, wherein, when the rate of gradation change upon wiping is measured by the following method, the rate of gradation change T1 upon wiping in the CD direction of the nonwoven fabric and the rate of gradation change T2 upon wiping in the MD direction of the nonwoven fabric satisfy T2/T1>1.0.
(Method for measuring the rate of change in gradation when wiping)
A transparent acrylic plate (thickness 3 mm, product number: KAC9143-1S, manufactured by Hikari Corporation) with a mark (a square frame with sides of 1.5 cm drawn with a pen) is placed on the opposite side of the mark with three drops (0.05 ml per drop) of artificial dirt (a mixture of blue acrylic paint (product name: acrylic paint (blue), manufactured by Daiso Industries Co., Ltd.), ethanol (product name: Wako First Grade Ethanol (99.5), manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) and distilled water (blue acrylic paint: ethanol: distilled water = 10: 50: 40 (mass ratio))) and spread evenly over an area larger than the area of the mark, and air-dried for 60 minutes, and the grayscale gradation A within the mark (excluding the area of the square frame drawn with a pen) after air-drying is measured. Image analysis processing software (software name: Image J) is used for gradation measurement. Another acrylic plate is placed on the side with the artificial stain to protect the stain, and image data is captured with a scanner (product name: Docu Centre VIIC4473, manufactured by Fuji Xerox Co., Ltd.). The captured image data is split into RGB channels (Split Channels), and the average value of the gradation within the mark for only the red component is confirmed using a histogram, and this is designated as grayscale gradation A.
The artificial dirt applied to the acrylic plate is attached to a plate-shaped jig (wiping area 6 cm x 6 cm) of a sample nonwoven fabric (100 parts by weight of nonwoven fabric is impregnated with 300 parts by weight of distilled water) of 10 cm in the MD direction and 6 cm in the CD direction, and while applying a pressure of 510 Pa, it is moved back and forth twice in a specified direction at a speed of 10 mm/sec and a movement distance of 100 mm. After wiping, the grayscale gradation B of the artificial dirt remaining on the acrylic plate is obtained in the same manner as for gradation A, and the gradation change rate T (%) is calculated according to the following formula.

(Aspect 9)
The nonwoven fabric of any of Aspects 1 to 8, wherein the nonwoven fabric contains 30% by mass or more of cellulosic fibers when the mass of the nonwoven fabric is 100% by mass.
(Aspect 10)
The nonwoven fabric of any one of aspects 1 to 9, wherein the nonwoven fabric has a basis weight of 30 g/ ^m2 or more and 80 g/ ^m2 or less.
(Aspect 11)
A wiper comprising the nonwoven fabric of any one of embodiments 1 to 10.
(Aspect 12)
Producing a fibrous web;
placing the fibrous web on a support and subjecting the fibrous web to an entanglement treatment using a high-pressure fluid flow;
In the entanglement treatment, it is assumed that the fiber web has a first section and a second section extending along the CD direction in a striped pattern,
The entanglement is performed under different processing conditions when the first section of the fiber web is subjected to the entanglement treatment from the processing conditions when the second section of the fiber web is subjected to the entanglement treatment, so that the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, have different patterns, or one of the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, has no pattern, and the other has a pattern.
A method for manufacturing nonwoven fabric.
(Aspect 13)
13. The method for producing a nonwoven fabric according to claim 12, wherein the entanglement treatment of the first section of the fibrous web and the entanglement treatment of the second section of the fibrous web are performed simultaneously by placing the fibrous web on a single support.
(Aspect 14)
A method for producing a nonwoven fabric according to aspect 13, wherein the support used in the entangling treatment has two types of weave patterns regularly repeated along the MD direction.
(Aspect 15)
A method for producing a nonwoven fabric according to aspect 14, wherein the support used in the entanglement treatment has plain weave portions and twill weave portions alternately and repeatedly formed along the MD direction.
(Aspect 16)
The method for producing a nonwoven fabric according to any one of aspects 12 to 15, further comprising a total entanglement treatment in which the entire fiber web is entangled with a high-pressure fluid flow under the same treatment conditions before the entanglement treatment.

In the nonwoven fabric of the present disclosure, each linear portion constituting the striped pattern extends in a direction perpendicular to the direction in which the tensile strength is greater, and even if the nonwoven fabric is moved back and forth on the surface of an object in a direction perpendicular to the direction in which each linear portion of the striped pattern extends, it is unlikely to become twisted. In addition, the striped pattern includes at least a first intertwined portion and a second intertwined portion, each of which has a different pattern, or one of which has no pattern and the other has a pattern. Therefore, the nonwoven fabric of the present disclosure is suitable for use as hygiene products such as wipers, sanitary napkins, disposable diapers for babies and disposable diapers for adults, hand towels, face masks, sanitary masks, filters, or poultices.

Claims (16)

A nonwoven fabric including a first entangled portion and a second entangled portion,
the first intertwined portions and the second intertwined portions are present in a striped pattern,
The second intertwined portion and the first intertwined portion have different patterns, or one of the second intertwined portion and the first intertwined portion has no pattern and the other has a pattern;
A tensile strength S1 of the nonwoven fabric in a direction in which the first entangled portions extend and a tensile strength S2 of the nonwoven fabric in a direction perpendicular to the direction in which the first entangled portions extend satisfy S1<S2,
The direction in which the first entangled portion extends is the CD direction of the nonwoven fabric.
Nonwoven fabric. The nonwoven fabric according to claim 1, wherein the dimension of the first intertwined portion in a direction perpendicular to the direction in which the first intertwined portion extends is 2 mm or more and 200 mm or less. The nonwoven fabric according to claim 1 or 2, wherein the dimension of the second intertwined portion in a direction perpendicular to the direction in which the second intertwined portion extends is 2 mm or more and 200 mm or less. The first intertwined portion has a pattern, and the pattern of the first intertwined portion is a diagonal line pattern,
The acute angle between the oblique lines of the oblique line pattern and the extension direction of the first intertwined portions is 10 degrees or more and 80 degrees or less.
The nonwoven fabric according to any one of claims 1 to 3. The nonwoven fabric according to any one of claims 1 to 4, wherein the second intertwined portion has a pattern, and the pattern of the second intertwined portion is an open hole pattern in which the open holes are regularly arranged. 6. The nonwoven fabric according to claim 5, wherein the area of each opening in the opening pattern is 0.50 ^mm2 or less. The nonwoven fabric according to any one of claims 1 to 6, in which the coefficient of variation of thickness of the cut surface perpendicular to the CD direction of the nonwoven fabric is 0.09 or more. The nonwoven fabric according to any one of claims 1 to 7, wherein, when the rate of change in gradation upon wiping is measured by the following method, the rate of change in gradation upon wiping in the CD direction of the nonwoven fabric (T1) and the rate of change in gradation upon wiping in the MD direction of the nonwoven fabric (T2) satisfy T2/T1>1.0.
(Method for measuring the rate of change in gradation when wiping)
A transparent acrylic plate (thickness 3 mm, product number: KAC9143-1S, manufactured by Hikari Corporation) with a mark (a square frame with sides of 1.5 cm drawn with a pen) is placed on the opposite side of the mark with three drops (0.05 ml per drop) of artificial dirt (a mixture of blue acrylic paint (product name: acrylic paint (blue), manufactured by Daiso Industries Co., Ltd.), ethanol (product name: Wako First Grade Ethanol (99.5), manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.) and distilled water (blue acrylic paint: ethanol: distilled water = 10: 50: 40 (mass ratio))) and spread evenly over an area larger than the area of the mark, and air-dried for 60 minutes, and the grayscale gradation A within the mark (excluding the area of the square frame drawn with a pen) after air-drying is measured. Image analysis processing software (software name: Image J) is used for gradation measurement. Another acrylic plate is placed on the side with the artificial stain to protect the stain, and image data is captured with a scanner (product name: Docu Centre VIIC4473, manufactured by Fuji Xerox Co., Ltd.). The captured image data is split into RGB channels (Split Channels), and the average value of the gradation within the mark for only the red component is confirmed using a histogram, and this is designated as grayscale gradation A.
The artificial dirt applied to the acrylic plate is attached to a plate-shaped jig (wiping area 6 cm x 6 cm) of a sample nonwoven fabric (100 parts by weight of nonwoven fabric is impregnated with 300 parts by weight of distilled water) of 10 cm in the MD direction and 6 cm in the CD direction, and while applying a pressure of 510 Pa, it is moved back and forth twice in a specified direction at a speed of 10 mm/sec and a movement distance of 100 mm. After wiping, the grayscale gradation B of the artificial dirt remaining on the acrylic plate is obtained in the same manner as for gradation A, and the gradation change rate T (%) is calculated according to the following formula.

The nonwoven fabric according to any one of claims 1 to 8, wherein the nonwoven fabric contains 30% by mass or more of cellulosic fibers when the mass of the nonwoven fabric is taken as 100% by mass. The nonwoven fabric according to any one of claims 1 to 9, wherein the nonwoven fabric has a basis weight of 30 g/ ^m2 or more and 80 g/ ^m2 or less. A wiper comprising the nonwoven fabric according to any one of claims 1 to 10. Producing a fibrous web;
placing the fibrous web on a support and subjecting the fibrous web to an entanglement treatment using a high-pressure fluid flow;
In the entanglement treatment, it is assumed that the fiber web has a first section and a second section extending along the CD direction in a striped pattern,
The entanglement is performed under different processing conditions when the first section of the fiber web is subjected to the entanglement treatment from the processing conditions when the second section of the fiber web is subjected to the entanglement treatment, so that the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, have different patterns, or one of the first entangled portion, which is the first section after the entanglement treatment, and the second entangled portion, which is the second section after the entanglement treatment, has no pattern, and the other has a pattern.
A method for manufacturing nonwoven fabric. The method for producing a nonwoven fabric according to claim 12, wherein the entanglement treatment of the first section of the fiber web and the entanglement treatment of the second section of the fiber web are performed simultaneously by placing the fiber web on a single support. The method for producing a nonwoven fabric according to claim 13, wherein the support used in the entanglement treatment has two types of weave structure regularly repeated along the MD direction. The method for producing a nonwoven fabric according to claim 14, wherein the support used in the entanglement treatment is one in which plain weave portions and twill weave portions are alternately and repeatedly formed along the MD direction. The method for producing a nonwoven fabric according to any one of claims 12 to 15, further comprising a total entanglement process in which the entire fiber web is entangled with a high-pressure fluid flow under the same processing conditions before the entanglement process is performed.

Images