Long fiber nonwoven fabric, textile product, wiping cloth, product for clean room, laminate, and production method of long fiber nonwoven fabric

Abstract

To provide a long fiber nonwoven fabric excellent in scraping-off performance.SOLUTION: The long fiber nonwoven fabric of the present disclosure includes a plurality of long fibers that contain a thermoplastic resin. The long fiber nonwoven fabric has a plurality of embossed parts formed of a part of the long fibers bonded. The embossed parts are arranged in an irregular pattern.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a long-fiber nonwoven fabric, a textile product, a wiping cloth, an article for a clean room, a laminate, and a method for producing the long-fiber nonwoven fabric. [Background technology]

[0002] Nonwoven fabrics made of ultrafine fibers have excellent flexibility, etc. Therefore, nonwoven fabrics made of ultrafine fibers are widely used as materials for clothing, disposable diapers, sanitary products, wiping cloths, and the like.

[0003] Patent Document 1 discloses a split fiber nonwoven fabric. The split fiber nonwoven fabric is obtained by spinning a conjugate long fiber by discharging a specific polyester (A) and a specific polyolefin (B) from a spinneret having a conjugate spinning nozzle so that the polyester (A) portion and the polyolefin (B) portion are in contact with each other, cooling the spun conjugate long fiber with a cooling fluid, further applying tension with the cooling fluid or another fluid to thin the long fiber, depositing the long fiber on a collecting belt, and then splitting the conjugate long fiber into the polyester (A) portion and the polyolefin (B) portion using a high-pressure liquid stream. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 105503 Summary of the Invention [Problem to be solved by the invention]

[0005] The long-fiber nonwoven fabric disclosed in Patent Document 1 has room for improvement in dust scraping performance.

[0006] An object of one embodiment of the present disclosure is to provide a long-fiber nonwoven fabric, a textile product, a wiping cloth, an article for a clean room, and a laminate that have excellent scraping performance. Another problem to be solved by another embodiment of the present disclosure is to provide a method for producing a long-fiber nonwoven fabric that can produce a long-fiber nonwoven fabric with excellent scraping performance. [Means for solving the problem]

[0007] Specific means for solving the above problems include the following aspects. <1> a plurality of long fibers including a thermoplastic resin; a plurality of embossed portions formed by bonding portions of the plurality of long fibers; A long-fiber nonwoven fabric, wherein the plurality of embossed portions are arranged in an irregular pattern. <2> The plurality of long fibers include a plurality of polyester-based polymer long fibers (A) and a plurality of propylene-based polymer long fibers (B). <1> The long fiber nonwoven fabric according to claim 1. <3> The plurality of polyester polymer long fibers (A) include a plurality of polylactic acid polymer long fibers. <2> The long fiber nonwoven fabric according to claim 1. <4> The plurality of long fibers include a plurality of ultrafine long fibers formed by splitting a plurality of split fibers. <1> ~ <3> 1. The long-fiber nonwoven fabric according to any one of 1 to 8. <5> The 50% fineness of the plurality of long fibers is 0.50 denier or less. <1> ~ <4> 1. The long-fiber nonwoven fabric according to any one of 1 to 8. <6> The aforementioned <1> ~ <5> A textile product comprising the long-fiber nonwoven fabric according to any one of the above. <7> The aforementioned <1> ~ <5> A wiping cloth comprising the long-fiber nonwoven fabric according to any one of the above. <8> The aforementioned <1> ~ <5> 1. A clean room article comprising the long-fiber nonwoven fabric according to any one of the above. <9> It comprises multiple layers, At least one layer of the plurality of layers is <1> ~ <5> A laminate comprising the long-fiber nonwoven fabric according to any one of the above. <10> The aforementioned <1> ~ <5> A method for producing a long-fiber nonwoven fabric according to any one of the above, providing a web having a plurality of long fibers comprising the thermoplastic resin; subjecting the web to a heat and pressure treatment using an embossing roll having a surface temperature of 55°C or less to produce a long-fiber nonwoven fabric precursor; and entangling the long-fiber nonwoven fabric precursor with a high-pressure fluid stream to produce the long-fiber nonwoven fabric. <11> the plurality of long fibers includes a plurality of split fibers, The split fiber has at least one portion (A) containing a polylactic acid polymer and at least one portion (B) containing a propylene polymer, In preparing the long-fiber nonwoven fabric, the long-fiber nonwoven fabric precursor is entangled with a high-pressure fluid flow, and a plurality of ultrafine long fibers are split from one split fiber to prepare the long-fiber nonwoven fabric; The plurality of ultrafine long fibers include at least one polyester long fiber (A) containing the portion (A) and at least one propylene polymer long fiber (B) containing the portion (B). <10> A method for producing the long-fiber nonwoven fabric described in 1. <12> The surface temperature of the embossing roll is 30°C to 45°C. <10> or <11> A method for producing the long-fiber nonwoven fabric described in 1. [Effects of the Invention]

[0008] According to one embodiment of the present disclosure, there are provided a long-fiber nonwoven fabric, a textile product, a wiping cloth, an article for a clean room, and a laminate, which have excellent scraping performance. According to another aspect of the present disclosure, there is provided a method for producing a long-fiber nonwoven fabric, which can produce a long-fiber nonwoven fabric having excellent scraping performance. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of a long-fiber nonwoven fabric showing an example of an embossed pattern. [Figure 2] FIG. 2 is a front view of a long-fiber nonwoven fabric showing another example of an embossed pattern. [Figure 3]FIG. 3 is a schematic diagram showing an example of a manufacturing apparatus used for closed-type spin-lay deposition. [Figure 4] FIG. 4 is a schematic diagram showing an example of a spinneret for split fibers. [Figure 5] FIG. 5 is a front photograph of the long-fiber nonwoven fabric of Example 1. [Figure 6] FIG. 6 is a front photograph of the long-fiber nonwoven fabric of Example 2. [Figure 7] FIG. 7 is a front photograph of the long-fiber nonwoven fabric of Example 3. [Figure 8] FIG. 8 is a front photograph of the long-fiber nonwoven fabric of Comparative Example 1. [Figure 9] FIG. 9 is a front photograph of the long-fiber nonwoven fabric of Comparative Example 2. [Figure 10] FIG. 10 is a front photograph of the long-fiber nonwoven fabric of Comparative Example 3. [Figure 11] FIG. 11 is a front photograph of the long-fiber nonwoven fabric of Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0023] The following describes embodiments of the present disclosure. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the embodiments. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In the numerical ranges described in this disclosure, the upper or lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified. In this disclosure, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the purpose of that process is achieved. In this disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In this disclosure, the content of each component in a composition means the total amount of the multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component are present in the composition.

[0011] (1) Long-fiber nonwoven fabric The long-fiber nonwoven fabric of the present disclosure comprises a plurality of long fibers containing a thermoplastic resin. The long-fiber nonwoven fabric has a plurality of embossed portions formed by bonding some of the long fibers. The embossed portions are arranged in an irregular pattern.

[0012] In this disclosure, "long fiber nonwoven fabric" refers to a nonwoven fabric made by bonding a web made of filaments (long fibers) using one or more bonding methods. "Web" refers to a sheet composed only of fibers. "Nonwoven fabric" refers to a flat fiber assembly that has a certain level of structural strength obtained by at least one of physical and chemical methods, excluding weaving, knitting, and papermaking. Specifically, long fiber nonwoven fabrics are spunbond nonwoven fabrics, meltblown nonwoven fabrics, or flash-spun nonwoven fabrics. "Spunbond nonwoven" refers to a nonwoven fabric made by one or more bonding methods (e.g., embossing) to a web made by spinlaid lamination. "Spinlaid" refers to a web made by extruding molten or dissolved polymers through a nozzle and laying the filaments onto a moving screen. "Meltblown nonwoven" refers to a nonwoven fabric made by one or more bonding methods to a web made by meltblown lamination. "Meltblown lamination" refers to a method in which molten polymer is extruded into a high-velocity, hot gas stream to form fibers that are then laid onto a moving screen to form a web. "Flash-spun nonwoven fabric" refers to a nonwoven fabric made of highly fibrillated filaments bonded together by one or more bonding methods to a web produced by flash-spun lamination. "Flash-spun lamination" refers to a method of spinning a polymer solution through a nozzle under certain conditions, evaporating the solvent immediately after spinning, and laying the fibers on a moving screen to produce a web.

[0013] The "embossed portion" refers to a non-fibrous portion where a portion of a plurality of long fibers is bonded. Specifically, the embossed portion is a bonded portion having an area of ​​0.1 mm 2 The presence or absence of embossed areas can be determined by observing the surface or cross section of the fiber assembly and determining whether or not there are embossed areas (areas of bonded areas of 0.1 mm2 or more). 2 This is done by checking whether or not there is a site where the value is equal to or greater than the threshold.

[0014] Hereinafter, the direction parallel to the moving direction of the screen on which the long fibers are layered is also referred to as the "machine direction (MD)," and the direction perpendicular to the moving direction of the screen on which the long fibers are layered is also referred to as the "cross direction (CD)."

[0015] The machine direction (MD) of a filament nonwoven can be determined from the filament nonwoven itself by measuring the tensile strength of the filament nonwoven. Generally, in the production of long-fiber nonwoven fabrics, the screen movement speed is set relatively fast from the viewpoint of productivity. Therefore, the long fibers contained in the web tend to be oriented parallel to the machine direction (MD) when laid on the screen. As a result, the tensile strength of a long-fiber nonwoven fabric in the machine direction (MD) is higher than the tensile strength of the long-fiber nonwoven fabric in the cross direction (CD). Therefore, by measuring the tensile strength of the long-fiber nonwoven fabric, the machine direction (MD) of the long-fiber nonwoven fabric can be determined from the long-fiber nonwoven fabric itself.

[0016] "The plurality of embossed portions are arranged in an irregular pattern" means that the pattern of the embossed portions does not have any regularity. Specifically, "the plurality of embossed portions are arranged in an irregular pattern" means that the plurality of embossed portions arranged in a regular pattern have been destroyed by the spraying of the high-pressure fluid flow. Details of the high-pressure fluid flow will be described later. The "plurality of embossed portions arranged in a regular pattern" means that the following condition (X1) and the following condition (X3) are satisfied, or the following condition (X2) and the following condition (X3) are satisfied. Condition (X1): Adjacent embossed sections must be spaced equally apart in both the machine direction (MD) and cross direction (CD). Condition (X2): Groups of multiple embossed patterns are repeated at equal intervals in both the machine direction (MD) and the cross direction (CD). Condition (X3): Embossed parts of the same shape must be lined up Examples of "plural embossed portions arranged in a regular pattern" include (i) a case where the shape of the embossed portions on the long-fiber nonwoven fabric is the same as the shape of the convex portions on the embossing roll used to form the embossed portions, or (ii) a case where the shape of the embossed portions on the long-fiber nonwoven fabric is different from the shape of the convex portions on the embossing roll, and the difference between the embossed area ratio of the long-fiber nonwoven fabric and the convex area ratio of the embossing roll is ±10% or less, or the difference between the embossed area ratio of the long-fiber nonwoven fabric and the convex area ratio of the embossing roll is more than ±10%.

[0017] In condition (X1), the shape of the embossed portion may be a circle, ellipse, oval, square, diamond, rectangle, or square, or a continuous shape based on any of these shapes. In condition (X1), the area ratio of the embossed portion is preferably 5% to 50%. The "area ratio of the embossed portion" refers to the ratio of the total area of ​​multiple embossed portions to the area of ​​the long-fiber nonwoven fabric observed when a 10 mm x 10 mm test piece is taken from the long-fiber nonwoven fabric and the contact surface of the test piece with the embossing roll is observed under an electron microscope (magnification: 100x). An example of an embossed portion is shown in Figure 1. In Figure 1, reference numeral 80 denotes the long-fiber nonwoven fabric, reference numeral 81 denotes a square embossed portion, and reference numeral 82 denotes a non-embossed portion.

[0018] In condition (X2), "embossed pattern group" refers to a unit pattern divided by embossed portions. Examples of embossed patterns include quilt patterns, herringbone patterns, and bar patterns. Figure 2 shows an example of an embossed pattern. In Figure 2, reference numeral 90 denotes a long-fiber nonwoven fabric, reference numeral 91 denotes an embossed portion, reference numeral 92 denotes a non-embossed portion, reference numeral 93 denotes an embossed line, and reference numeral 94 denotes a quilt type (i.e., an embossed pattern). "Embossed line" refers to a plurality of embossed portions arranged in a line.

[0019] In condition (X3), "embossed portions of the same shape are lined up" means that the following condition (X31) or the following condition (X32) is satisfied. Specifically, "embossed portions of the same shape are lined up" means that the following condition (X33) is satisfied. Condition (X31): Each of the multiple embossed portions is arranged in the same shape. Condition (X32): The embossed portions that form the embossed pattern group must be aligned in the same shape. Condition (X33): When 20 repeating patterns of the embossed portion are taken out and the areas of the 20 repeating patterns are compared, there must be 10 or more repeating patterns where the area difference expressed by the following formula (i) is within ±10%. Formula (i): Area difference = [(measured value - average value) ÷ average value] × 100

[0020] The long-fiber nonwoven fabric of the present disclosure has the above-described configuration and therefore has excellent scraping performance. This effect is presumably due to, but not limited to, the following reasons. In the embossed portions, some of the multiple long fibers are bonded together. Therefore, dust is difficult to scrape off from the embossed portions. Generally, the multiple embossed portions are arranged in a regular pattern. In the present disclosure, the multiple embossed portions are arranged in an irregular pattern. The irregular arrangement of the multiple embossed portions indicates that the multiple embossed portions arranged in a regular pattern are broken down by the high-pressure fluid flow. In other words, in the present disclosure, the total area of ​​the multiple embossed portions from which dust is difficult to scrape is smaller than the total area of ​​the multiple embossed portions when the multiple embossed portions are arranged in a regular pattern. As a result, it is presumed that the long-fiber nonwoven fabric of the present disclosure has excellent scraping performance.

[0021] The long-fiber nonwoven fabric is a sheet-like material. The layer structure of the long-fiber nonwoven fabric is appropriately selected depending on the application of the long-fiber nonwoven fabric, and may be a single-layer structure or a multi-layer structure of at least two layers.

[0022] The basis weight of the long fiber nonwoven fabric is not particularly limited, but from the viewpoint of weight reduction, it is preferably 5 g / m 2 ~100g / m 2 , more preferably 5 g / m 2 ~70g / m 2 is.

[0023] The thickness of the long-fiber nonwoven fabric is adjusted appropriately depending on the application of the long-fiber nonwoven fabric, and may be 0.1 mm to 0.7 mm.

[0024] The long-fiber nonwoven fabric may be a spunbond nonwoven fabric, a meltblown nonwoven fabric, or a flash-spun nonwoven fabric, and among these, from the viewpoint of imparting excellent mechanical strength to the long-fiber nonwoven fabric, the long-fiber nonwoven fabric is preferably a spunbond nonwoven fabric.

[0025] (1.1) Long fibers The filament nonwoven fabric of the present disclosure comprises a plurality of filaments.

[0026] The fineness of the long fibers is appropriately selected depending on the application of the long-fiber nonwoven fabric, and is preferably 0.001 denier to 2.00 denier, more preferably 0.001 denier to 1.20 denier. The method for measuring the fineness of the long fibers is the same as that described in the examples.

[0027] The 50% fineness of the plurality of long fibers is preferably 0.50 denier or less. This suggests that the long-fiber nonwoven fabric of the present disclosure has superior scraping performance compared to a fabric in which the 50% fineness of the plurality of long fibers is not 0.50 denier or less. From the viewpoint of improving the scraping performance of the long-fiber nonwoven fabric, the 50% fineness of the plurality of long fibers is more preferably 0.10 denier to 0.50 denier, and particularly preferably 0.10 denier to 0.40 denier.

[0028] The "50% fineness" refers to the fiber diameter corresponding to 50% by volume of the cumulative number of long fibers counted from the small fiber diameter side in the distribution of the number of long fibers relative to their fiber diameters.

[0029] The cross-sectional shape of the long fibers is not particularly limited, and examples thereof include circular, elliptical, and irregular cross-sectional shapes.

[0030] The type of long fiber is appropriately selected depending on the application of the long-fiber nonwoven fabric. The type of long fiber may be a plurality of ultrafine long fibers formed by splitting a split fiber (hereinafter simply referred to as "ultrafine long fiber"), a composite fiber, or a single-component fiber. "Split fiber" refers to a fiber that has the property of being split into multiple fibers from a single fiber. It is preferable that the composite fiber has two or more thermoplastic resins as its constituent components. Examples of the types of composite fiber include a core-sheath type, a side-by-side type, an islands-in-sea type, and a side-by-side type. A core-sheath type composite fiber has only to have a core portion and a sheath portion, and may be either a concentric core-sheath type or an eccentric core-sheath type. An eccentric sheath-core type composite fiber may have a core portion exposed on the surface, or the core portion may not be exposed on the surface. An islands-in-sea type composite fiber has a sea phase and multiple island phases.

[0031] Whether or not a fiber is an "ultrafine long fiber" can be determined by observing the cross section of the long fiber using an electron microscope. The cross section of an ultrafine long fiber is usually irregular. The cross section of the long fiber that constitutes a spunbonded nonwoven fabric or a meltblown nonwoven fabric is usually circular or elliptical.

[0032] (1.1.1) Thermoplastic resin The long fibers include a thermoplastic resin. The long fibers may be made of a thermoplastic resin.

[0033] Examples of the thermoplastic resin include polyester polymers (A), olefin polymers (B), polyamide polymers (e.g., nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyimide, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyacrylonitrile, polycarbonate, ionomer, polybutylene succinate, etc. The thermoplastic resins may be used alone or in combination of two or more.

[0034] "Polyester polymer" refers to a polymer containing polyester as a structural unit. "Olefin polymer" refers to a polymer containing an olefin-derived structural unit as a main component. "Main component" refers to a component whose content relative to the total amount of the polymer is 50 mass% or more. A "polyamide-based polymer" is a polymer that contains polyamide as a structural unit.

[0035] (1.1.1.1) Polyester polymer (A) The polyester polymer (A) may be an aromatic polyester or an aliphatic polyester, etc. The polyester polymer (A) may be used alone or in combination of two or more. Examples of aromatic polyesters include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate-isophthalate copolymer, polyethylene naphthalate, and poly-1,4-cyclohexylene dimethylene terephthalate. Examples of aliphatic polyesters include polylactic acid polymers (such as poly-L-lactic acid polymers), poly 3-hydroxybutyrate, poly 3-hydroxyvalerate, polycaprolactone, polyethylene succinate, polybutylene succinate, and polyglycolic acid.

[0036] The melting point (Tme) of the polyester polymer (A) is not particularly limited and is preferably 100° C. to 300° C., more preferably 150° C. to 300° C. If the melting point (Tme) is low, it may be difficult to solidify the polyester portion when spinning it with the polyolefin polymer (B) described below to obtain split fibers. On the other hand, if the melting point (Tme) is high, sufficient cooling may not be achieved during spinning, and fusion of the long fibers may occur due to delayed cooling.

[0037] The melt flow rate (MFR: ASTM D-1238, 210°C, 2160 g load) of the polyester polymer (A) is not particularly limited, but is preferably 1 g / 10 min to 500 g / 10 min, more preferably 5 g / 10 min to 500 g / 10 min. The polyester polymer (A) may contain a polymer containing a biomass-derived raw material.

[0038] (1.1.1.2) Olefin polymer (B) Examples of the olefin polymer (B) include an ethylene polymer, a propylene polymer, a 1-butene polymer, a 4-methyl-1-pentene polymer, an ethylene-acid (derivative) copolymer, and crystalline polystyrene. The olefin polymer (B) may be used alone or in combination of two or more. Examples of the ethylene polymer include ethylene homopolymer (ie, polyethylene), high-pressure low-density polyethylene, linear low-density polyethylene (so-called LLDPE), medium-density polyethylene, and high-density polyethylene. Examples of propylene polymers include homopolymers of propylene (i.e., polypropylene) and copolymers of propylene with one or more α-olefins (excluding propylene). Examples of α-olefins (excluding propylene) include ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Examples of the 1-butene polymer include poly-1-butene, 1-butene-ethylene random copolymer, and 1-butene-propylene random copolymer. Examples of 4-methyl-1-pentene polymers include poly4-methyl-1-pentene, 4-methyl-1-pentene-1-decene random copolymers, and copolymers of 4-methyl-1-pentene and one or more α-olefins having 12 to 20 carbon atoms. Examples of the ethylene-acid (derivative) copolymer include ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ionomer. Examples of crystalline polystyrene include ethylene-styrene copolymers and isotactic polystyrene. The olefin polymer (B) may contain a polymer containing a raw material derived from biomass.

[0039] (1.1.2) Additives The long fibers may further contain additives in addition to the thermoplastic resin, or may contain no additives. Examples of additives include antioxidants, weather stabilizers, light stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, and pigments. The additives may be used alone or in combination of two or more.

[0040] (1.1.3) Preferred embodiment The plurality of long fibers preferably includes a plurality of polyester long fibers (A) and a plurality of propylene-based polymer long fibers (B), which makes the long-fiber nonwoven fabric of the present disclosure easier to split with a high-pressure fluid stream than when the fabric does not include a plurality of polyester long fibers (A) and a plurality of propylene-based polymer long fibers (B).

[0041] The term "polyester polymer continuous fiber (A)" refers to a continuous fiber containing a polyester polymer (A) as a main component. Specifically, the polyester polymer continuous fiber (A) refers to a continuous fiber having a polyester polymer (A) content of 80 mass% or more based on the total amount of the continuous fiber. "Polypropylene-based polymer long fiber (B)" refers to a long fiber containing a polypropylene-based polymer as a main component. Specifically, the polypropylene-based polymer long fiber (B) refers to a long fiber having a polypropylene-based polymer content of 80 mass% or more based on the total amount of the long fiber.

[0042] The fineness, 50% fineness, cross-sectional shape and type of each of the polyester polymer long fiber (A) and the polypropylene polymer long fiber (B) may be the same as those exemplified for the long fiber.

[0043] When the plurality of long fibers includes a plurality of polyester-based polymer long fibers (A) and a plurality of propylene-based polymer long fibers (B), the ratio (A:B) of the mass of the plurality of polyester-based polymer long fibers (A) to the mass of the plurality of propylene-based polymer long fibers (B) is not particularly limited, but is preferably 90:10 to 90:10, more preferably 70:30 to 30:70, and even more preferably 50:50.

[0044] When the plurality of long fibers includes a plurality of polyester polymer long fibers (A) and a plurality of propylene polymer long fibers (B), the plurality of polyester polymer long fibers (A) preferably include a plurality of polylactic acid polymer long fibers, which makes the long-fiber nonwoven fabric of the present disclosure more easily splittable with a high-pressure fluid flow than when the plurality of polyester long fibers (A) do not include a plurality of polylactic acid polymer long fibers.

[0045] "Polylactic acid polymer continuous fiber" refers to a continuous fiber whose main component is a polylactic acid polymer. Specifically, polylactic acid polymer continuous fiber (A) refers to a continuous fiber whose polylactic acid polymer content is 80 mass% or more based on the total amount of the continuous fiber.

[0046] The content of the plurality of polylactic acid polymer long fibers is preferably 80% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and even more preferably 100% by mass, based on the total amount of the plurality of polyester long fibers (A).

[0047] The plurality of long fibers preferably includes a plurality of ultrafine long fibers formed by splitting a plurality of split fibers, which is presumably why the long fiber nonwoven fabric of the present disclosure has superior scraping performance compared to a case where the plurality of long fibers does not include a plurality of ultrafine long fibers.

[0048] When the plurality of long fibers includes a plurality of ultrafine long fibers, all of the plurality of split fibers may be split into a plurality of ultrafine long fibers, or a portion of the plurality of split fibers may be split into a plurality of ultrafine long fibers. The plurality of ultrafine long fibers preferably includes a plurality of polyester long fibers (A) and a plurality of propylene-based polymer long fibers (B).

[0049] (1.8) Purpose The applications of the long-fiber nonwoven fabric of the present disclosure are not particularly limited, and examples thereof include clothing (e.g., interlining or adhesive interlining), medical (e.g., surgical gowns or coverings), construction (e.g., roofing materials or tufted carpet substrates), civil engineering (e.g., drainage materials or filtration materials), vehicles (e.g., automobile interiors or automobile parts), hygiene (e.g., diapers, sanitary products, first aid supplies, cleaning products, or masks), interiors (e.g., carpets, furniture components, building materials, wall coverings, or decorative items), bedding (e.g., futon bags, pillowcases, or sheets), agriculture (e.g., greenhouse sheets or seedbed sheets), leather (e.g., artificial leather base fabric or synthetic leather base fabric), daily necessities (e.g., storage supplies, packaging materials, or bags), and industrial materials (e.g., industrial materials, electrical materials, or product substrates).

[0050] (2) Textile products The textile product of the present disclosure includes the long-fiber nonwoven fabric of the present disclosure. The textile product of the present disclosure has the above-described configuration and therefore has excellent scraping performance.

[0051] The textile products are not particularly limited, and examples thereof include absorbent articles (e.g., disposable diapers or sanitary products), hygiene articles (e.g., masks), medical articles (e.g., bandages), clothing materials, and packaging materials.

[0052] (3) Wiping cloth The wiping cloth of the present disclosure includes the long-fiber nonwoven fabric of the present disclosure. The textile product of the present disclosure has the above-described configuration and therefore has excellent wiping performance.

[0053] In the wiping cloth of the present disclosure, the long-fiber nonwoven fabric of the present disclosure preferably constitutes the wiping surface. The wiping cloth of the present disclosure may contain a nonwoven fabric other than the long-fiber nonwoven fabric (such as a long-fiber nonwoven fabric containing cellulose fibers to impart water absorbency) or a resin (such as polyvinyl alcohol, which has water absorbency), as long as the object of the present disclosure is not impaired. The wiping cloth of the present disclosure may be subjected to a nap-raising treatment, embossing treatment, coloring treatment, calendaring treatment, punching treatment, or the like. The long-fiber nonwoven fabric of the present disclosure may contain an active agent, a softener, a chemical (such as oils), a deodorizing agent, an antibacterial agent, or an antifungal agent, as needed, to enhance its cleaning and hygienic effects.

[0054] (4) Clean room items The clean room article of the present disclosure includes the long-fiber nonwoven fabric of the present disclosure. The clean room article of the present disclosure has the above-described configuration and therefore has excellent scraping performance. Examples of clean room items include wiping cloths, clean clothing, and masks.

[0055] (5) Laminate The laminate of the present disclosure includes a plurality of layers, at least one of which contains the long-fiber nonwoven fabric of the present disclosure. Because the laminate of the present disclosure has the above-described configuration, it has excellent scraping performance. The laminate of the present disclosure may or may not include other layers that do not include the long-fiber nonwoven fabric of the present disclosure. Examples of other layers include spunbond nonwoven fabrics, meltblown nonwoven fabrics, films (e.g., porous films), woven fabrics, and knitted fabrics. For example, a laminate including a spunbond nonwoven fabric with a relatively large fiber diameter is preferably used for applications such as simultaneously wiping large and small particle size dust. The method for integrating multiple layers is not particularly limited, and examples include entanglement treatment using a specific means (e.g., needle punching, water jetting, or ultrasonic sealing), heat fusion treatment using a hot embossing roll, and adhesive bonding. Examples of uses of the laminate of the present disclosure include wiping cloths, clean clothes, and masks.

[0056] (6) Manufacturing method of long-fiber nonwoven fabric The method for producing a long-fiber nonwoven fabric of the present disclosure is a method for producing a long-fiber nonwoven fabric of the present disclosure. The method for producing a long-fiber nonwoven fabric of the present disclosure includes: Preparing a web having a plurality of long fibers containing a thermoplastic resin (hereinafter also referred to as the "preparation step"); a heating and pressurizing treatment of the web using an embossing roll having a surface temperature of 55°C or less to produce a long-fiber nonwoven fabric precursor (hereinafter also referred to as the "embossing step"); and entangling the long-fiber nonwoven fabric precursor with a high-pressure fluid flow to produce the long-fiber nonwoven fabric (hereinafter also referred to as the "entangling step"). The preparation step, embossing step, and entangling step are carried out in this order.

[0057] The method for producing a long-fiber nonwoven fabric according to the present disclosure has the above-described configuration, and therefore can produce a long-fiber nonwoven fabric with excellent scraping performance. This effect is presumably due to, but not limited to, the following reasons. In the present disclosure, the embossing step results in the long-fiber nonwoven fabric precursor having a plurality of embossed portions. The plurality of embossed portions of the long-fiber nonwoven fabric precursor are arranged in a regular pattern. The entangling step causes the plurality of embossed portions arranged in the regular pattern to collapse. As a result, the long-fiber nonwoven fabric of the present disclosure is produced. In other words, it is presumed that the method for producing a long-fiber nonwoven fabric of the present disclosure can produce a long-fiber nonwoven fabric with excellent scraping performance.

[0058] (6.1) Preparation process In the preparation step, a web having a plurality of long fibers containing a thermoplastic resin is prepared.

[0059] The method for preparing the web is not particularly limited, and examples thereof include spin-lay lamination, melt-blown lamination, and flash-spun lamination. When the plurality of long fibers includes a plurality of segmented fibers, the method for preparing the web is preferably spin-lay lamination. Details of spin-lay lamination when the plurality of long fibers includes a plurality of segmented fibers will be described later.

[0060] (6.2) Embossing process In the embossing step, the web is subjected to a heat and pressure treatment at 55°C or less using an embossing roll to produce a long-fiber nonwoven fabric precursor. The long fibers contained in the long-fiber nonwoven fabric precursor are bonded together. Therefore, the long-fiber nonwoven fabric precursor is less likely to unravel than the web.

[0061] In the heat and pressure treatment, the web is sandwiched between an embossing roll and a flat roll. The embossing roll has a plurality of protrusions arranged in a regular pattern on its surface. The embossing roll transfers the shape of the top surfaces of the plurality of protrusions to some of the plurality of fibers contained in the web. In this way, the embossing roll forms a plurality of embossed portions arranged in a regular pattern on the web. The shape of the top surfaces of the plurality of protrusions arranged in a regular pattern on the embossing roll is the same as the shapes exemplified for the plurality of embossed portions arranged in a regular pattern described above. From the viewpoint of scraping performance, the area ratio of the plurality of protrusions on the embossing roll (hereinafter also referred to as "embossed area ratio") is preferably 5% to 50%, more preferably 5% to 18%, and particularly preferably 5% to 15%. In the long-fiber nonwoven fabric precursor, the plurality of embossed portions are arranged in a regular pattern.

[0062] The surface temperature of the embossing roll is 55° C. or lower. The surface temperature of the embossing roll is preferably 30° C. to 45° C. When the surface temperature of the embossing roll is 30° C. to 45° C., a long-fiber nonwoven fabric with superior scraping performance can be obtained. The surface temperature of the embossing roll may be 60°C or higher, or may be 100°C or higher.

[0063] In the present disclosure, the "surface temperature of the embossing roll" refers to the temperature measured by a thermometer placed on the surface of the embossing roll.

[0064] The surface temperature of the flat roll is not particularly limited, and may be 30°C to 45°C, or 30°C to 100°C.

[0065] In the present disclosure, the "surface temperature of the flat roll" refers to the temperature measured by a thermometer installed on the surface of the flat roll.

[0066] The pressure for the heat and pressure treatment is not particularly limited, but is preferably 0.2 MPa to 3 MPa, more preferably 0.5 MPa to 1 MPa, from the viewpoint of forming a plurality of embossed portions in a regular pattern on the long-fiber nonwoven fabric precursor. The pressure for the heat and pressure treatment is adjusted by adjusting the position of the embossing roll relative to the position of the flat roll.

[0067] (6.3) Confounding process In the entanglement process, a long-fiber nonwoven fabric precursor is entangled with a high-pressure fluid stream to produce a long-fiber nonwoven fabric. The spraying of the high-pressure fluid stream breaks down the multiple embossed portions arranged in a regular pattern on the long-fiber nonwoven fabric precursor. As a result, a long-fiber nonwoven fabric is obtained in which multiple embossed portions are arranged in an irregular pattern. Additionally, the long-fiber nonwoven fabric is less likely to unravel than the long-fiber nonwoven fabric precursor.

[0068] An example of the high-pressure fluid flow is a high-pressure water flow (water jet).

[0069] The diameter of each nozzle that generates a high-pressure fluid flow is not particularly limited, but is preferably 0.07 mm to 0.15 mm. The distance between adjacent nozzles is not particularly limited, but is preferably 0.5 mm to 1.5 mm.

[0070] The fluid pressure of the high-pressure fluid flow is not particularly limited, but is preferably 10 kgf / cm 2 ~100kgf / cm 2 , more preferably 30 kgf / cm 2~70kgf / cm 2 The fluid pressure of the high-pressure fluid flow is 30 kgf / cm 2 ~70kgf / cm 2 If so, the fibers can be split.

[0071] the plurality of long fibers includes a plurality of split fibers, The split fiber has at least one portion (A) containing a polylactic acid polymer and at least one portion (B) containing a propylene polymer, In preparing the long-fiber nonwoven fabric (i.e., in the entangling step), the long-fiber nonwoven fabric precursor is entangled with a high-pressure fluid flow, and a plurality of ultrafine long fibers are split from one split fiber to prepare the long-fiber nonwoven fabric; The plurality of ultrafine long fibers preferably include at least one polyester-based polymer long fiber (A) containing the portion (A) and at least one propylene-based polymer long fiber (B) containing the portion (B). As a result, the method for producing a long-fiber nonwoven fabric of the present disclosure can produce a long-fiber nonwoven fabric with superior scraping performance.

[0072] (7) Example of spin-lay stacking An example of spinlay lamination in which the plurality of long fibers includes a plurality of split fibers will be described in detail below with reference to Fig. 3. Fig. 3 is a schematic diagram showing an example of a manufacturing apparatus used in closed spinlay lamination. In closed spinlay lamination, a group of continuous fibers formed by melt-spinning a resin composition is stretched while being cooled in a closed space.

[0073] A manufacturing apparatus 100 is used for the spin-lay deposition.

[0074] (7.1) Manufacturing equipment The manufacturing apparatus 100 includes a spinning section 10. The spinning section 10 includes an extruder 11A, an extruder 11B, a split fiber spinneret 12, a cooling chamber 13, a cooling air supply section 14, a cooling air supply section 15, and a stretching section 16. The extruder 11A extrudes a melt of the resin composition (A). The extruder 11B extrudes a melt of the resin composition (B). The split fiber spinneret 12 spins the melt of the resin composition (A) and the melt of the resin composition (B). The cooling chamber 13 cools the continuous fiber group 1 spun from the split fiber spinneret 12. The continuous fiber group 1 includes a plurality of split fibers. The cooling air supply section 14 and the cooling air supply section 15 supply cooling air A into the cooling chamber 13 and the stretching section 16. The stretching section 16 stretches the continuous fiber group 1.

[0075] (7.1) Melting First, resin composition (A) is introduced into extruder 11A, and resin composition (B) is introduced into extruder 11B. Resin composition (A) contains a polylactic acid-based polymer. Resin composition (B) contains a propylene-based polymer. Resin composition (A) introduced into extruder 11A is melt-kneaded in extruder 11A. The melt of resin composition (A) is extruded from extruder 11A. Resin composition (B) introduced into extruder 11B is melt-kneaded in extruder 11B. The melt of resin composition (B) is extruded from extruder 11B.

[0076] The melting temperature of the resin composition (A) is not particularly limited as long as it is equal to or higher than the softening temperature or melting temperature of the resin composition (A) and lower than the thermal decomposition temperature of the resin composition (A), and is appropriately set depending on the physical properties of the resin composition (A), etc. The melting temperature of the resin composition (B) is not particularly limited as long as it is equal to or higher than the softening temperature or melting temperature of the resin composition (B) and lower than the thermal decomposition temperature of the resin composition (B), and is appropriately set depending on the physical properties of the resin composition (B), etc.

[0077] (7.2) Spinning The melt of resin composition (A) and the melt of resin composition (B) are introduced into the split fiber spinneret 12, and are extruded and spun from the split fiber spinneret 12. This forms a continuous fiber group 1. The continuous fiber group 1 includes a plurality of split fibers.

[0078] The splittable fiber spinneret 12 has a plurality of nozzles. The plurality of nozzles are configured so that the resin compositions (A) and (B) are arranged radially, parallelly, or side by side. For example, the plurality of spinning nozzles may be arranged in a row.

[0079] Split fiber spinnerets 12A-12I, which are examples of split fiber spinnerets, are shown in Figures 4(a)-4(i). As shown in Figures 4(a)-4(i), split fiber spinnerets 12A-12I have multiple spinning nozzles 121 and multiple spinning nozzles 122. A melt of resin composition (A) is supplied to spinning nozzle 121, and a melt of resin composition (B) is supplied to spinning nozzle 122.

[0080] The temperature of the split fiber spinneret 12 is adjusted appropriately depending on the physical properties of the resin composition (A) and the resin composition (B). The temperature of the split fiber spinneret 12 is preferably 180°C to 240°C, more preferably 190°C to 230°C, and even more preferably 200°C to 225°C.

[0081] The hole diameter of the splittable fiber spinneret 12 is not particularly limited, and may be 0.05 mm to 1.00 mm.

[0082] The discharge rate of the melt of the resin composition (A) per hole from the splittable fiber spinneret 12 is preferably 0.1 g / min to 3.0 g / min, more preferably 0.3 g / min to 1.0 g / min, from the viewpoint of spinnability. The per-hole discharge rate of the melt of resin composition (B) from the splittable fiber spinneret 12 is preferably 0.1 g / min to 3.0 g / min, more preferably 0.3 g / min to 1.0 g / min, from the viewpoint of spinnability. The single-hole discharge rate of the melt of resin composition (A) and the single-hole discharge rate of the melt of resin composition (B) may be the same or different.

[0083] (7.3) Stretching The continuous fiber group 1 is introduced into the cooling chamber 13. The continuous fiber group 1 introduced into the cooling chamber 13 is cooled by cooling air A. The cooling air A is supplied into the cooling chamber 13 and the stretching section 16 from at least one of a cooling air supply section 14 and a cooling air supply section 15. The cooled continuous fiber group 1 is introduced into the stretching section 16 located downstream of the cooling chamber 13. The stretching section 16 has a narrow passage section 16a and a cylindrical section 16b. The cylindrical section 16b is formed at the end of the narrow passage section 16a on the lower side (i.e., on the screen 21 side) in the vertical direction (i.e., in the direction of gravity) of the narrow passage section 16a. The narrow passage section 16a is narrow. The cylindrical section 16b is cylindrical. The hollow section of the cylindrical section 16b widens downward as shown in FIG. 3. The continuous fiber group 1 introduced into the stretching section 16 is stretched by increasing the speed of the cooling air in the narrow passage section 16a. After being stretched, the continuous fiber group 1 passes through the cylindrical section 16b, whereupon it is dispersed and collected on the screen 21.

[0084] The temperature of the cooling air A is not particularly limited as long as it is a temperature at which the resin compositions (A) and (B) are solidified. The temperature of the cooling air A is preferably 5°C to 50°C, more preferably 10°C to 40°C, and even more preferably 15°C to 30°C.

[0085] The air speed is not particularly limited, but from the viewpoint of spinnability, it is preferably 2000 m / min to 4000 m / min, more preferably 2200 m / min to 3600 m / min. The "air speed" is the cross-sectional area (m 2 ) for the flow rate of cooling air A (Nm 3 / min).

[0086] (7.4) Collection The dispersed continuous fiber group 1 is efficiently collected on the screen 21 by the suction unit 22. The suction unit 22 is disposed below the collecting surface of the screen 21. In this way, a web 2 is formed. The web 2 includes a plurality of split fibers. The web 2 may be made of a plurality of split fibers. [Example]

[0087] Hereinafter, the present disclosure will be illustrated by examples and comparative examples, but the present disclosure is not limited to the following examples.

[0088] [1] Examples and Comparative Examples [1.1] Example 1 As the polyester polymer (A), a poly-L-lactic acid polymer (manufactured by NatureWorks, trade name: INGEO BIOPOLYMER 6252D, L-lactic acid / D-lactic acid (copolymerization ratio) = 98.6 mol% / 1.4 mol%, melting point (Tme): 165°C) was prepared. The MFR of the poly-L-lactic acid polymer at 210°C under a load of 2160 g was 75 g / 10 min.

[0089] As the polyolefin polymer (B), polypropylene [Mw / Mn=2.8, melting point (Tme): 162° C.] was prepared. The MFR of the polypropylene at 230° C. under a load of 2160 g was 66 g / 10 min.

[0090] [1.1.1] Spin-lay lamination process A manufacturing apparatus 100 (see FIG. 3) was used to perform the spin-lay lamination. The polyester polymer (A) was introduced into an extruder 11A, and the polyolefin polymer (B) was introduced into an extruder 11B, and each was melted. The molding temperature of the polyester polymer (A) was 230°C. The molding temperature of the polyolefin polymer (B) was 230°C.

[0091] The melt of the polyester polymer (A) and the melt of the polyolefin polymer (B) were supplied to a split fiber spinneret 12A (see FIG. 4) to extrude split fibers. The split fiber spinneret 12A had a total of 16 segments. The mass ratio (A / B) of the mass of the polyester polymer (A) to the mass of the polyolefin polymer (B) in the split fibers was 50 / 50. The resin output rate (single-hole output rate) of the polyester polymer (A) per location in the split fiber spinneret 12A was 0.44 g / min. The resin output rate (single-hole output rate) of the polyolefin polymer (B) per location in the split fiber spinneret 12A was 0.30 g / min.

[0092] The split fibers extruded from the split fiber spinneret 12A were drawn at an air speed of 2647 m / min while being cooled with air (25°C), and then deposited on a moving screen 21. This produced a web.

[0093] [1.1.2] Embossing process While the web was being transported, it was sandwiched between an embossing roll and a flat roll (surface temperature: 25°C) and subjected to a heat and pressure treatment. This resulted in a long-fiber nonwoven fabric precursor. The pressure used in the heat and pressure treatment was 1 MPa. The line speed was 5 m / min.

[0094] [1.1.2.1] Embossing roll Shape of the convex part: Diamond Arrangement of convex parts: Regular pattern (same spacing between adjacent convex parts) Embossed area ratio: 10% Embossing temperature: Room temperature (25°C)

[0095] [1.1.3] Confounding process To split the split fibers, a water jet process was applied once to the surface of the long-fiber nonwoven fabric precursor while conveying the long-fiber nonwoven fabric precursor using a nozzle with a hole diameter of 0.11 mm. This resulted in a long-fiber nonwoven fabric. When applying the water jet process, the distance between the nozzle spraying water and the long-fiber nonwoven fabric precursor was 10 cm. The water pressure for the water jet process was 40 kgf / cm. 2 The line speed was 5 m / min. The weight of the long fiber nonwoven fabric was 50 g / m 2 A front photograph of the long-fiber nonwoven fabric of Example 1 is shown in Fig. 5. In Fig. 5, the roughly diamond-shaped white areas indicate embossed areas. The same applies to Figs. 6 to 11.

[0096] [1.2] Examples 2 to 3 and Comparative Examples 1 to 4 Long-fiber nonwoven fabrics were obtained in the same manner as in Example 1, except that the embossing temperature was changed to the temperature shown in Table 1. Front photographs of the long-fiber nonwoven fabrics of Examples 2 and 3 and Comparative Examples 1 to 4 are shown in Figs.

[0097] [1.3] Comparative Example 5 A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the embossing step was not carried out.

[0098] [2]Measurement method The fineness, basis weight, presence or absence of a regular pattern, and scraping performance of the continuous fiber nonwoven fabrics obtained in the examples and comparative examples were evaluated by the following methods. The measurement results are shown in Table 1.

[0099] [2.1] Fineness The long-fiber nonwoven fabric was observed under an electron microscope (a scanning electron microscope "SU3500" manufactured by Hitachi High-Tech Corporation). 30 long fibers were selected from the obtained image. The thickness of each long fiber was measured for each of the 30 long fibers. The average of these measurements was taken as the "fineness."

[0100] [2.2] Metsuke Five test pieces of 200 mm (MD) x 50 mm (CD) and five test pieces of 200 mm (CD) x 50 mm (MD) were taken from the long-fiber nonwoven fabric. The mass of each sample was measured. The average value obtained was converted to the mass per unit area of ​​the test piece, and the result was rounded to the nearest tenth to obtain the "basis weight (g / m)." 2 )"

[0101] [2.3] Presence or absence of embossments arranged in an irregular pattern Whether or not the multiple embossed portions formed on the long-fiber nonwoven fabric were arranged in an irregular pattern was evaluated based on the results of evaluating the even spacing of the embossed portions and the uniformity of the shapes of the embossed portions as described below.

[0102] [2.3.1] Evaluation of the uniformity of embossed areas [2.3.1.1] Evaluation method Whether adjacent embossed portions are repeated at equal intervals is confirmed according to the measurement example shown below.

[0103] Observe the morphology of the long-fiber nonwoven fabric (using a scanning electron microscope (SEM), an optical microscope, and visual inspection, etc.). The distance between adjacent embossed sections in the machine direction (MD) and the distance between adjacent embossed sections in the cross direction (CD) are measured at 10 points each, and the average of the 10 measured values ​​is calculated. The average value is compared with the measured value. An example of the distance between adjacent embossed patterns is shown in Figure 1. In Figure 1, the symbol "LMD" indicates the distance between adjacent embossed sections 81 in the machine direction (MD). The symbol "LCD" indicates the distance between adjacent embossed sections 81 in the cross direction (CD). If an embossed portion is present but any of the 10 distances cannot be measured, it is evaluated that the adjacent embossed portions are not arranged at equal intervals.

[0104] [2.3.1.2] Details The morphology of the long-fiber nonwoven fabric was observed, and the distance between adjacent embossed portions in the machine direction (MD) of the long-fiber nonwoven fabric was measured at 10 points. The average value of the 10 measured values ​​(hereinafter also referred to as "La") was calculated. The percentage (Y1) (%) of the difference between La and each of the 10 measured values ​​was calculated using the following formula (ii): Formula (ii): Difference ratio (Y1) = [(measured value - La) / La] × 100

[0105] Of the 10 measured values, the number of measured values ​​for which the percentage difference (Y1) was within ±10% (hereinafter also referred to as "number of equally spaced intervals (MD)") was counted. The results are shown in Table 1. When the number of equally spaced intervals (MD) was 5 or more, it was evaluated that adjacent embossed portions were arranged at equal intervals in the machine direction (MD) of the long-fiber nonwoven fabric.

[0106] Similarly, the distance between adjacent embossed portions in the cross direction (CD) of the long-fiber nonwoven fabric was measured at 10 points. The average value of the 10 measurements (hereinafter also referred to as "Lb") was calculated. The percentage (Y2) (%) of the difference between Lb and each of the 10 measurements was calculated using the following formula (iii): Formula (iii): Difference ratio (Y2) = [(measured value - Lb) / Lb] × 100

[0107] Of the 10 measured values, the number of measured values ​​for which the percentage difference (Y2) was within ±10% (hereinafter referred to as the "number of equally spaced intervals (CD)") was counted. The results are shown in Table 1. If the number of equally spaced intervals (CD) was 5 or more, the continuous fiber nonwoven fabric was evaluated as having an equally spaced arrangement between adjacent embossed portions in the cross direction (CD).

[0108] When adjacent embossed portions of a long-fiber nonwoven fabric are arranged at equal intervals in both the machine direction (MD) and the cross direction (CD), the long-fiber nonwoven fabric is considered to satisfy the condition (X1) that "adjacent embossed portions are arranged at equal intervals in both the machine direction (MD) and the cross direction (CD)." If embossed portions are present but adjacent embossed portions are not equally spaced in at least one of the machine direction (MD) and cross direction (CD) of the long-fiber nonwoven fabric, the condition (X1) is deemed not to be satisfied.

[0109] [2.3.2] Evaluation of uniformity of embossed shape [2.3.2.1] Evaluation method The evaluation of the uniformity of the shapes of the plurality of embossed portions is carried out as follows.

[0110] Observe the morphology of the long fiber nonwoven fabric (using SEM, optical microscope, etc.). Twenty embossed sections that form each of the multiple embossed sections or groups of embossed patterns are taken out, the area of ​​each of the 20 embossed sections is calculated, and the average area of ​​the 20 embossed sections is calculated. The area of ​​each of the 20 embossed sections is compared with the average area. If an embossed portion is present but any of the 20 points of the above area cannot be measured, it is evaluated that the shapes of the multiple embossed portions are not identical.

[0111] [2.3.2.2] Details The morphology of the long-fiber nonwoven fabric was observed, and the area of ​​each embossed portion was measured at 20 points. The average value (S) of the 20 measured values ​​was calculated. The percentage difference (Y3) (%) between S and each of the 20 measured values ​​was calculated using the following formula (iv): Formula (iv): Difference ratio (Y3) = [(measured value - S) / S] x 100

[0112] Of the 20 measurement values, the number of measurement values ​​for which the difference rate (Y3) was within ±10% (hereinafter also referred to as the "number of equivalent areas") was counted. The results are shown in Table 1.

[0113] If the number of equivalent areas is 10 or more, it is evaluated that "embossed portions of the same shape are arranged side by side" (the above-mentioned condition (X3)) is satisfied. If the number of equivalent areas is less than 10 points, it is determined that the condition (X3) is not satisfied.

[0114] [2.3.3] Evaluation When the conditions (X1) and (X3) are satisfied, the multiple embossed portions of the long-fiber nonwoven fabric are evaluated as "multiple embossed portions arranged in a regular pattern." If at least one of the conditions (X1) and (X3) is not satisfied, the embossed portions of the long-fiber nonwoven fabric are evaluated as not being "embossed portions arranged in a regular pattern." In other words, the embossed portions of the long-fiber nonwoven fabric are evaluated as being "embossed portions arranged in an irregular pattern." In the evaluation of the even spacing of the embossed portions and the evaluation of the uniformity of the shape of the embossed portions, if no embossed portions are observed by morphological observation, the long-fiber nonwoven fabric is evaluated as having no embossed portions. On the other hand, if embossed portions are observed by shape observation but the absolute number of embossed portions contained in the long-fiber nonwoven fabric is less than 20 or 10 points as described in the above evaluation examples, the above evaluation can be applied to the number of measurable embossments. For example, if the number of measurable embossed portions is 6, and the requirement of "being arranged in a regular pattern" is met for 3 or more points, which is more than half of that number, the fabric is evaluated as meeting the condition of "embossed portions being arranged in a regular pattern."

[0115] [2.4] Scraping performance A fixed amount (0.50 g) of JIS dust (JIS test powder 1, type 9 (talc)) is uniformly dispersed on a P tile (manufactured by Sangetsu Corporation). The area that contributes to wiping is 100 cm. 2 An evaluation tool was prepared by attaching a long-fiber nonwoven fabric to a sponge (manufactured by Hikari Co., Ltd.) so that the measurement was performed as follows: A load of 500 g was applied to the evaluation tool, and the evaluation tool was moved back and forth twice in the cross direction (CD) while in contact with the P tile. This caused the evaluation tool to scrape off the JIS dust on the P tile. The mass of the long-fiber nonwoven fabric before wiping and the mass of the long-fiber nonwoven fabric after wiping were measured. The dust adsorption amount was calculated using the following formula (v). The dust adsorption rate was calculated using the following formula (vi). Based on the calculated dust adsorption rate, the scraping performance of the long-fiber nonwoven fabric was evaluated according to the following evaluation criteria. Acceptable scraping performance was evaluated as "A" or "B." Formula (v): Dust adsorption amount (g) = mass of long-fiber nonwoven fabric after wiping - mass of long-fiber nonwoven fabric after wiping Formula (vi): Dust adsorption rate (%) = dust adsorption amount / mass of dispersed JIS dust (0.50 g)

[0116] [2.4.1] Evaluation criteria A: Dust adsorption rate is 60% or more B: Dust adsorption rate is 50% to 59% C: Dust adsorption rate is 40% to 49% D: Dust adsorption rate is 0% to 39%

[0117] [Table 1]

[0118] In Table 1, "long fiber (A)" indicates polyester polymer long fiber (A). "PLA" indicates polylactic acid polymer. "long fiber (B)" indicates propylene polymer long fiber (B). "PP" indicates propylene polymer. "WJ" indicates water jet processing. "Yes" in "Irregular pattern" indicates that multiple embossed portions are arranged in an irregular pattern. "No" in "Irregular pattern" indicates that multiple embossed portions are not arranged in an irregular pattern (i.e., multiple embossed portions are arranged in a regular pattern).

[0119] [3] Results In Comparative Examples 1 to 4, the multiple embossed portions were arranged in a regular pattern. In other words, the multiple embossed portions were not arranged in an irregular pattern. Furthermore, in Comparative Example 5, there were no embossed portions. Therefore, the evaluation result of the scraping performance was not either "A" or "B." As a result, it was found that the long-fiber nonwoven fabrics of Comparative Examples 1 to 5 were not "long-fiber nonwoven fabrics excellent in scraping performance."

[0120] In Examples 1 to 3, the multiple embossed portions were arranged in an irregular pattern. Therefore, the evaluation results for the scraping performance were "A" or "B." As a result, the long-fiber nonwoven fabrics of Examples 1 to 3 were found to be "long-fiber nonwoven fabrics with excellent scraping performance."

Claims

1. a plurality of long fibers including a thermoplastic resin; a plurality of embossed portions formed by bonding portions of the plurality of long fibers; A long-fiber nonwoven fabric, wherein the plurality of embossed portions are arranged in an irregular pattern.

2. 2. The long-fiber nonwoven fabric according to claim 1, wherein the plurality of long fibers comprises a plurality of polyester-based polymer long fibers (A) and a plurality of propylene-based polymer long fibers (B).

3. The continuous fiber nonwoven fabric according to claim 2, wherein the plurality of polyester polymer continuous fibers (A) comprises a plurality of polylactic acid polymer continuous fibers.

4. The continuous fiber nonwoven fabric according to any one of claims 1 to 3, wherein the plurality of continuous fibers comprises a plurality of ultrafine continuous fibers formed by splitting a plurality of split fibers.

5. The continuous fiber nonwoven fabric according to any one of claims 1 to 3, wherein the 50% fineness of the plurality of continuous fibers is 0.50 denier or less.

6. A textile product comprising the long-fiber nonwoven fabric according to any one of claims 1 to 3.

7. A wiping cloth comprising the long-fiber nonwoven fabric according to any one of claims 1 to 3.

8. An article for a clean room, comprising the long-fiber nonwoven fabric according to any one of claims 1 to 3.

9. It comprises multiple layers, A laminate, wherein at least one layer of the plurality of layers comprises the long-fiber nonwoven fabric according to any one of claims 1 to 3.

10. A method for producing the long-fiber nonwoven fabric according to claim 1, providing a web having a plurality of long fibers comprising the thermoplastic resin; using an embossing roll having a surface temperature of 55°C or less, subjecting the web to a heat and pressure treatment to prepare a long-fiber nonwoven fabric precursor; and entangling the long-fiber nonwoven fabric precursor with a high-pressure fluid stream to produce the long-fiber nonwoven fabric.

11. the plurality of long fibers includes a plurality of split fibers, The split fiber has at least one portion (A) containing a polylactic acid polymer and at least one portion (B) containing a propylene polymer, In preparing the long-fiber nonwoven fabric, the long-fiber nonwoven fabric precursor is entangled with a high-pressure fluid flow, and a plurality of ultrafine long fibers are split from one split fiber to prepare the long-fiber nonwoven fabric; 11. The method for producing a long-fiber nonwoven fabric according to claim 10, wherein the plurality of ultrafine long fibers comprise at least one polyester long fiber (A) containing the portion (A) and at least one propylene-based polymer long fiber (B) containing the portion (B).

12. The method for producing a long-fiber nonwoven fabric according to claim 10 or 11, wherein the surface temperature of the embossing roll is 30°C to 45°C.

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