Composite nonwoven fabric and method for manufacturing the same

Abstract

The composite nonwoven fabric of the present invention includes: a filament region containing crimped filament fibers as the main component, and a synthetic fiber nonwoven fabric region containing synthetic fibers comprising polyolefin resin as the main component.

Description

[Technical Field]

[0001] This disclosure relates to a composite nonwoven fabric and a method for manufacturing the same. [Previous Technology]

[0002] Nonwoven fabrics used in hygiene materials such as diapers or bandages require excellent softness because they come into contact with the skin. Polyolefin-based nonwoven fabrics are sometimes used as hygiene materials. Silk is also known as a material for nonwoven fabrics. For example, Patent Document 1 describes a medical silk nonwoven fabric made solely of short fibers obtained by cutting silk fibers. Patent Document 2 describes a three-layer structure of silk nonwoven fabric—silk nonwoven fabric, mesh fabric, and silk nonwoven fabric—manufactured using a prescribed manufacturing method, which possesses the unique smooth feel of silk fibers and can also be used for clothing fabrics with abrasion resistance. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 97 / 07273 [Patent Document 2] Japanese Patent Application Publication No. 2003-105661 [Summary of the Invention]

[0004] [Problems to be Solved by the Invention] However, according to the research of the inventors, it has been clarified that when polyolefin-based nonwoven fabrics are used alone, their softness and liquid retention are sometimes insufficient. Furthermore, according to the research of the inventors, it has been clarified that the silk nonwoven fabric described in Patent Document 1, because it contains only silk fibers as its fibers, sometimes lacks strength. Additionally, according to the research of the inventors, it has been clarified that the silk nonwoven fabric described in Patent Document 2, because its mesh fabric is generally stiff and thick, sometimes lacks softness.

[0005] One aspect of this disclosure is to provide a composite nonwoven fabric with excellent softness, strength and liquid retention, and a method for manufacturing the same.

[0006] [Means for Solving the Problem] The methods for solving the problem include the following forms. <1> A composite nonwoven fabric comprising: a filament region containing crimped filament fibers as a main component; and a synthetic fiber nonwoven fabric region containing synthetic fibers containing polyolefin resin as a main component. <2> The composite nonwoven fabric as described in <1> has a thickness of 1.00 mm or less. <3> The composite nonwoven fabric as described in <1> or <2> has a unit area weight of 20 g / cm2 to 60 g / cm2. <4> The composite nonwoven fabric as described in <1> or <2>, wherein the filament fiber content relative to the total mass of the composite nonwoven fabric is 30% to 90% by mass. <5> The composite nonwoven fabric as described in <1> or <2> is a spunlace nonwoven fabric. <6> The composite nonwoven fabric as described in <1> or <2> has a tensile strength in the mechanical direction of 20 N / 50 mm or more. <7> The composite nonwoven fabric as described in <1> or <2>, wherein the tensile strength in the direction orthogonal to the mechanical direction when viewed from above is 5 N / 50 mm or more. <8> The composite nonwoven fabric as described in <1> or <2>, wherein the polyolefin resin contains a polypropylene resin. <9> The composite nonwoven fabric as described in <1> or <2>, wherein the average fiber diameter of the synthetic fibers is 10 μm to 30 μm. <10> The composite nonwoven fabric as described in <1> or <2>, wherein the synthetic fibers contain crimped fibers. <11> The composite nonwoven fabric as described in <1> or <2>, wherein the synthetic fiber nonwoven fabric region is derived from a spunbond meltblown spunbond (SMS) nonwoven fabric region, wherein the SMS nonwoven fabric contains two spunbond nonwoven fabrics as the outermost layers and at least one meltblown nonwoven fabric disposed between the two spunbond nonwoven fabrics. <12> A method for manufacturing a composite nonwoven fabric, comprising the steps of: preparing a filament web containing crimped filament fibers as a main component; preparing a synthetic fiber nonwoven fabric containing synthetic fibers comprising a polyolefin resin as a main component; and obtaining the composite nonwoven fabric by interlacing the filament web with the synthetic fiber nonwoven fabric. <13> The method for manufacturing a composite nonwoven fabric as described in <12>, wherein, in the step of obtaining the composite nonwoven fabric, the interlacing of the filament web with the synthetic fiber nonwoven fabric is performed by hydroentangling.

[0007] [Effects of the Invention] According to one aspect of the present invention, a composite nonwoven fabric with excellent softness, strength and liquid retention is provided, and a method for manufacturing the same is provided.

Implementation Method

[0008] In this disclosure, the numerical range indicated by "~" refers to the range including the values ​​recorded before and after "~" as both the lower and upper limits. In this disclosure, the amount of each component contained in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. Within the numerical ranges described in stages of this disclosure, the upper or lower limit recorded in one numerical range can be replaced with the upper or lower limit of other numerical ranges described in stages. Furthermore, within the numerical ranges described in this disclosure, the upper or lower limit of that range can be replaced with the values ​​shown in the embodiments.

[0009] [Composite Nonwoven Fabric] The composite nonwoven fabric disclosed herein includes: a filament region containing crimped filament fibers as the main component, and a synthetic fiber nonwoven fabric region containing synthetic fibers containing polyolefin resins as the main component. The composite nonwoven fabric disclosed herein may include other regions as needed.

[0010] The composite nonwoven fabric disclosed herein exhibits excellent softness, strength, and liquid retention. The reasons for this effect are presumably as follows: The composite nonwoven fabric disclosed herein is a composite nonwoven fabric containing synthetic fiber nonwoven regions, therefore exhibiting superior strength (especially tensile strength) compared to filament webs that do not contain synthetic fiber nonwoven regions. The composite nonwoven fabric disclosed herein is a composite nonwoven fabric containing filament regions, therefore exhibiting superior softness and liquid retention compared to synthetic fiber nonwoven fabrics that do not contain filament regions.

[0011] Furthermore, the main component of the filament region of the composite nonwoven fabric disclosed herein is crimped filament fibers (hereinafter also referred to as "crimped filament fibers"). Therefore, compared to the case where the main component of the filament region is non-crimped filament fibers (hereinafter also referred to as "non-crimped filament fibers"), the composite nonwoven fabric exhibits superior shape retention and peel strength (i.e., the strength in the thickness direction of the composite nonwoven fabric). Specifically, because the main component of the filament region is crimped filament fibers, when the composite nonwoven fabric disclosed herein is obtained by interweaving a filament web containing crimped filament fibers as the main component with a synthetic fiber nonwoven fabric containing synthetic fibers containing polyolefin resins as the main component, it is easy to integrate the filament web and the synthetic fiber nonwoven fabric. This improves the shape retention and peel strength (i.e., the strength in the thickness direction of the composite nonwoven fabric). Here, the term "web" in filament web refers to the entire fabric (e.g., nonwoven fabric, woven fabric, etc.).

[0012] In this disclosure, the main component refers to the component with the largest mass among all the components contained.

[0013] The composite nonwoven fabric disclosed herein may contain only one filament region or two or more filament regions. The composite nonwoven fabric disclosed herein may contain only one synthetic fiber nonwoven fabric region or two or more synthetic fiber nonwoven fabric regions. A preferred form of the composite nonwoven fabric disclosed herein is as follows: At least one filament region and at least one synthetic fiber nonwoven fabric region are arranged in the thickness direction of the composite nonwoven fabric.

[0014] From the viewpoint of the skin feel of the composite nonwoven fabric, a preferred form of the composite nonwoven fabric disclosed herein is form A, which includes: two filament regions disposed in the thickness direction of the composite nonwoven fabric; and at least one synthetic fiber nonwoven fabric region disposed between the two filament regions. The composite nonwoven fabric of form A may contain more than one filament region in addition to the two filament regions, provided that the necessary conditions of form A are met. For example, forms in which the filament regions and synthetic fiber nonwoven fabric regions are alternately arranged, and the total number of filament regions is three or more, are also included in form A, provided that the necessary conditions of form A are met.

[0015] The composite nonwoven fabric disclosed herein is preferably manufactured by interlacing a filament web containing crimped filament fibers as the main component with a synthetic fiber nonwoven fabric containing synthetic fibers containing polyolefin resin as the main component. In this way, filament regions are formed from regions originating from the filament web, and synthetic fiber nonwoven fabric regions are formed from regions originating from the synthetic fiber nonwoven fabric, thereby manufacturing the composite nonwoven fabric disclosed herein.

[0016] The composite nonwoven fabric disclosed herein is preferably a spunlace nonwoven fabric. The spunlace nonwoven fabric described herein is a nonwoven fabric formed by interlacing a silk fiber web containing crimped filaments as the main component with a synthetic fiber nonwoven fabric containing synthetic fibers containing polyolefin resins as the main component through a hydroentangling process (i.e., water-jet interlacing process). When the composite nonwoven fabric disclosed herein is a spunlace nonwoven fabric, the softness of the silk fibers is more effectively maintained in the composite nonwoven fabric.

[0017] Hereinafter, preferred physical properties of the composite nonwoven fabric are shown. The conditions for measuring these preferred physical properties can be found in the description of the examples.

[0018] <Thickness of the Composite Nonwoven Fabric> The thickness of the composite nonwoven fabric disclosed herein is preferably 1.00 mm or less, more preferably 0.20 mm to 1.00 mm, even more preferably 0.20 mm to 0.80 mm, and particularly preferably 0.25 mm to 0.60 mm. When the thickness of the composite nonwoven fabric is 1.00 mm or less, for example, when used as a sanitary material, the sanitary material can be made thinner. In addition, when the thickness of the composite nonwoven fabric is 1.00 mm or less, it tends to have better softness. The composite nonwoven fabric with a thickness of 1.00 mm or less can be obtained, for example, by hydroentangling as described later.

[0019] <Weight per unit area of ​​the composite nonwoven fabric> The weight per unit area of ​​the composite nonwoven fabric disclosed herein is preferably 20 g / cm² to 60 g / cm², more preferably 20 g / cm² to 50 g / cm². When the weight per unit area of ​​the composite nonwoven fabric is within the range described above, it tends to balance strength and thinness, and is therefore preferred.

[0020] In this disclosure, the weight per unit area of ​​the composite nonwoven fabric is the value obtained by dividing the mass of the composite nonwoven fabric by its area. In this disclosure, the thickness and weight per unit area of ​​the composite nonwoven fabric are measured using one or more samples taken from the composite nonwoven fabric. The total area of ​​the samples used in the measurement is set to be 250 cm² or more (e.g., 500 cm²).

[0021] <Fiber Content> The fiber content (more specifically, the combined content of crimped and non-crimped fibers) in the composite nonwoven fabric disclosed herein is preferably 30% to 90% by mass, more preferably 35% to 80% by mass, and even more preferably 40% to 70% by mass, relative to the total mass of the composite nonwoven fabric. When the crimped fiber content is 30% by mass or more, the composite nonwoven fabric tends to have superior softness and liquid retention, and is therefore preferred. When the crimped fiber content is 90% by mass or less, the composite nonwoven fabric tends to have superior strength, and is therefore preferred.

[0022] <Tensile Strength of Composite Nonwoven Fabric> The tensile strength (hereinafter also referred to as "MD tensile strength") of the composite nonwoven fabric disclosed herein is preferably 20 N / 50 mm or more. The MD tensile strength of the composite nonwoven fabric is more preferably 20 N / 50 mm to 70 N / 50 mm, and even more preferably 20 N / 50 mm to 50 N / 50 mm.

[0023] In this disclosure, the unit "N / 50 mm" refers to the tensile strength (N) in the length direction of the specimen measured using a specimen with a width of 50 mm.

[0024] In this disclosure, the MD in the tensile strength of the composite nonwoven fabric (i.e., the mechanical direction, hereinafter the same) refers to the MD of the synthetic fiber nonwoven fabric region. That is, the tensile strength of the composite nonwoven fabric with respect to the MD of the synthetic fiber nonwoven fabric region refers to the tensile strength of the composite nonwoven fabric with respect to the MD of the synthetic fiber nonwoven fabric region.

[0025] The tensile strength (hereinafter also referred to as "CD tensile strength") of the composite nonwoven fabric disclosed herein in the cross direction (CD direction) orthogonal to the mechanical direction when viewed from above is preferably 5 N / 50 mm or more. The CD tensile strength of the composite nonwoven fabric is more preferably 5 N / 50 mm to 30 N / 50 mm, and even more preferably 5 N / 50 mm to 20 N / 50 mm.

[0026] In this disclosure, the CD in the tensile strength of the composite nonwoven fabric (i.e., the direction orthogonal to the mechanical direction when viewed from above. The same applies below) refers to the CD of the synthetic fiber nonwoven fabric region. That is, the tensile strength of the composite nonwoven fabric CD refers to the tensile strength of the composite nonwoven fabric with respect to the CD of the synthetic fiber nonwoven fabric region.

[0027] The method for determining the MD tensile strength and CD tensile strength of the composite nonwoven fabric is shown in the examples described below. The length of the test piece is not limited to 200 mm as in the examples; any length sufficient to ensure a chuck-to-plate distance of 100 mm (e.g., 120 mm or more) is acceptable.

[0028] <Air permeability of composite nonwoven fabric> The air permeability (cm3 / cm2 / sec; hereinafter also expressed as "ccs") of the composite nonwoven fabric disclosed herein is preferably 50 ccs to 300 ccs, more preferably 80 ccs to 200 ccs. When the air permeability is 50 ccs or more, the skin is less likely to become stuffy when the composite nonwoven fabric is used in sanitary materials, which is therefore preferred. When the air permeability is 300 ccs or less, the liquid retention of the composite nonwoven fabric tends to be further improved, which is also preferred.

[0029] The air permeability of the composite nonwoven fabric is determined using one or more samples taken from the self-composite nonwoven fabric. The total area of ​​the samples used in the determination is 10,000 mm2 or more (e.g., 22,500 mm2).

[0030] <Peel strength of composite nonwoven fabric> The peel strength of the composite nonwoven fabric disclosed herein is preferably 0.3 N or more, more preferably 0.5 N to 2.0 N, and even more preferably 0.6 N to 1.5 N.

[0031] The method for determining the peel strength of composite nonwoven fabrics is shown in the examples described below.

[0032] <Stiffness and flexibility of composite nonwoven fabric> The MD stiffness and flexibility of the composite nonwoven fabric is preferably 35 mm to 60 mm, more preferably 40 mm to 50 mm. The CD stiffness and flexibility of the composite nonwoven fabric is preferably 20 mm to 30 mm, more preferably 21 mm to 16 mm.

[0033] The methods for determining the MD stiffness and CD stiffness of composite nonwoven fabrics are shown in the examples described below.

[0034] The preferred form of the filament region and the synthetic fiber nonwoven fabric will be described below.

[0035] <Silk Region> The silk region is a region containing crimped filaments as the main component. The silk region is preferably formed using a silk fiber web (e.g., silk fiber nonwoven fabric, silk fiber woven fabric, etc.) containing crimped filaments as the main component.

[0036] Crimped filament fiber is a fiber formed by crimping non-crimped filament fiber (i.e., uncrimped filament). Known methods can be used as methods for crimping non-crimped filament fiber. Examples of methods for crimping non-crimped filament fiber include: a gear crimping method in which the non-crimped filament fiber is passed between a pair of grooved rollers meshing like gears to form a sawtooth shape; a bending method in which the non-crimped filament fiber is pressed into the tubular portion of a funnel-shaped clamp including a tubular portion while bent into a sawtooth shape, and the pressed filament fiber is extruded from the tubular portion, thereby bending the non-crimped filament fiber; and so on. Known technologies can be applied without particular limitation to non-crimped filament fiber, methods for crimping non-crimped filament fiber, and crimped filament fiber, for example, Japanese Patent Application Publication No. 2003-105661 and Japanese Patent Application Publication No. 2006-207069, etc.

[0037] The filament region may also contain components other than crimped filament fibers. Examples of other components include non-crimped filament fibers and fibers other than filament fibers. Furthermore, when manufacturing a composite nonwoven fabric by interweaving a filament fiber web with a synthetic fiber nonwoven fabric, synthetic fibers may also be incorporated into the filament region derived from the filament fiber web through interweaving. The content of crimped filament fibers relative to the total mass of the filament region is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0038] The average fiber diameter of the crimped filaments contained in the filament region is preferably 2 μm to 50 μm, more preferably 3 μm to 30 μm, and even more preferably 5 μm to 20 μm. When the average fiber diameter of the crimped filaments is within the range described above, it is more suitable to form an interweaving with the synthetic fibers, and the peel strength of the composite nonwoven fabric tends to be further improved, which is therefore preferred. The average fiber diameter refers to the arithmetic mean of the fiber diameters of 30 crimped filaments.

[0039] The average fiber length of the crimped filaments contained in the filament region is preferably 10 mm to 100 mm, more preferably 20 mm to 80 mm, and even more preferably 30 mm to 70 mm. The average fiber length refers to the arithmetic mean of the fiber lengths of 30 crimped filaments. In addition, the fiber length of the crimped filaments is measured when the crimped shape is stretched straight.

[0040] From the viewpoint of further improving the shape retention and peel strength of the composite nonwoven fabric, the crimp spacing of the crimped filaments is preferably 0.2 mm to 3.0 mm, more preferably 0.5 mm to 2.0 mm. Here, the crimp spacing, when the shape of the crimped filaments is a repeating serrated shape of mountains and valleys, refers to the average distance between the apexes of adjacent mountains. The average distance is the arithmetic mean of 30 measured values ​​(distances).

[0041] From the viewpoint of further improving the shape retention and peel strength of the composite nonwoven fabric, the crimp of the crimped filament fibers is preferably 3% or more, more preferably 5% or more, and even more preferably 10% or more, and particularly preferably 15% or more. The upper limit of the crimp of the crimped filament fibers is preferably 80%, more preferably 50%, and even more preferably 40%. Here, crimp refers to the degree of crimping. The larger the value of the crimp, the greater the degree of crimping. The method for calculating the crimp ratio will be explained in the embodiments described later.

[0042] <Synthetic Fiber Nonwoven Fabric Region> The synthetic fiber nonwoven fabric region is a region containing synthetic fiber nonwoven fabric. Preferably, the synthetic fiber nonwoven fabric region is formed using synthetic fiber nonwoven fabric. Both the synthetic fiber nonwoven fabric region and the synthetic fiber nonwoven fabric used as its raw material contain synthetic fibers containing polyolefin resin as a main component. The content of said synthetic fibers relative to the total mass of the synthetic fiber nonwoven fabric region is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Similarly, the content of said synthetic fibers relative to the total mass of the synthetic fiber nonwoven fabric is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0043] The synthetic fiber may contain only one type of polyolefin resin, or it may contain two or more types. The content of polyolefin resin in the synthetic fiber (the total content in the case of two or more types) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, relative to the total mass of the synthetic fiber.

[0044] In this disclosure, polyolefin resin refers to a resin containing olefin units (i.e., structural units formed by olefin polymerization) as its main component. The content of olefin units relative to the total mass of the polyolefin resin is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Polyolefin resin may also have structural units other than olefin units.

[0045] The polyolefin resin may contain only one type of olefin unit or more than two types. That is, the polyolefin resin may be a homopolymer of one type of olefin or a copolymer of two or more types of olefins.

[0046] Examples of olefins used to form olefin units include: ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and other α-olefins.

[0047] From the viewpoint of balancing strength and flexibility, polyolefin resins preferably include polypropylene resins. In this case, the polypropylene resin in the polyolefin resin may be only one type or may be two or more types. Here, polypropylene resin refers to a resin containing propylene units (i.e., structural units formed by the polymerization of propylene) as a main component. The content of propylene units relative to the total mass of the polypropylene resin is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Polypropylene resins may contain structural units other than propylene units (preferably structural units derived from α-olefins other than propylene).

[0048] The melt flow rate (MFR) of the polypropylene resin (specifically, the MFR measured at 230°C and under a load of 2.16 kg according to American Society for Testing Material (ASTM) D 1238. The same applies hereinafter) is preferably 1 g / 10 min to 3,000 g / 10 min, more preferably 2 g / 10 min to 2,000 g / 10 min, even more preferably 10 g / 10 min to 1,000 g / 10 min, and particularly preferably 10 g / 10 min to 700 g / 10 min.

[0049] The polypropylene resin contained in the polyolefin resin is preferably at least one of propylene homopolymer and propylene-α-olefin copolymer (i.e., copolymer of propylene with α-olefin other than propylene).

[0050] The α-olefin (i.e., α-olefin other than propylene) in the propylene-α-olefin copolymer may be only one type or may be two or more types. Preferably, the α-olefin (i.e., α-olefin other than propylene) in the propylene-α-olefin copolymer is an α-olefin with 2 to 10 carbon atoms other than propylene (e.g., ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene). Preferably, the propylene-α-olefin copolymer is a propylene-ethylene copolymer, and more preferably, a propylene-ethylene random copolymer.

[0051] The α-olefin content in the propylene-α-olefin copolymer (i.e., the percentage of α-olefin units in all structural units of the propylene-α-olefin copolymer in mol%) is preferably 1 mol% to 40 mol%, more preferably 2 mol% to 30 mol%, further preferably 2 mol% to 20 mol%, and especially preferably 2 mol% to 10 mol%. The propylene content in the propylene-α-olefin copolymer (i.e., the percentage of propylene units in all structural units of the propylene-α-olefin copolymer in mol%) is preferably 60 mol% to 99 mol%, more preferably 70 mol% to 98 mol%, further preferably 80 mol% to 98 mol%, and especially preferably 90 mol% to 98 mol%.

[0052] The melting point of the propylene homopolymer is preferably above 155°C, more preferably 157°C to 165°C. The melting point of the propylene-α-olefin copolymer is preferably 120°C to 154°C, more preferably 130°C to 150°C.

[0053] When the polyolefin resin contains a polypropylene resin, the polyolefin resin may also contain other resins besides the polypropylene resin. When the polyolefin resin contains a polypropylene resin, the content of the polypropylene resin relative to the total mass of the polyolefin resin is preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0054] (Average fiber diameter) From the viewpoint of further promoting the interweaving of synthetic fibers and crimped fibers and further improving peel strength, the average fiber diameter of the synthetic fibers is preferably 10 μm to 30 μm. The method for determining the average fiber diameter of the synthetic fibers is shown in the examples described later.

[0055] The average fiber diameter is easily achieved when using a spunbonded nonwoven fabric as a synthetic fiber nonwoven fabric for forming the synthetic fiber nonwoven fabric area.

[0056] (Curled Fiber) From the viewpoint of further promoting the interweaving of synthetic fibers and crimped filaments and further improving peel strength, synthetic fibers are preferably those containing crimped fibers.

[0057] In this disclosure, the crimped fiber in the context of synthetic fibers refers to at least one of shaped fibers (i.e., fibers with asymmetrical cross-sections) and composite fibers containing two or more synthetic resins (i.e., crimped composite fibers). Preferably, the crimped fiber is a crimped composite fiber. The crimped composite fiber preferably comprises two or more polyolefin resins (preferably two or more polypropylene resins) that differ in at least one of their composition, molecular weight, and physical properties (e.g., crystallization temperature, melting point, softening point, crystallization rate, melt viscosity, etc.). Preferably, the crimped composite fiber is an eccentric core-sheath type crimped composite fiber. An eccentric core-sheath type crimped composite fiber refers to a crimped composite fiber in which, in the cross-section of the fiber (i.e., a section orthogonal to the fiber length), it consists of a core and a sheath surrounding at least a portion of the core, wherein the centers of the core and the sheath do not overlap. The eccentric core-sheath type crimped composite fiber preferably has a side-by-side cross-sectional shape. Here, the side-by-side cross-sectional shape refers to a shape in which the sheath only surrounds a portion of the core, with the remainder of the core exposed to the outside.

[0058] There are no particular limitations on the crimped composite fiber (e.g., eccentric core-sheath type crimped composite fiber), and for example, the crimped composite fiber known in Japanese Patent No. 4009196, Japanese Patent No. 5139669, Japanese Patent No. 5289459 and other known documents may be used.

[0059] As a crimped composite fiber, it is preferably an eccentric core-sheath type crimped composite fiber comprising a core and a sheath, wherein the core contains a first polyolefin resin and the sheath contains a second polyolefin resin different from the first polyolefin resin. In the eccentric core-sheath type crimped composite fiber, the mass ratio of the depth to the sheath (hereinafter also referred to as the mass ratio [core / sheath]) is preferably 0.05 to 5.00, more preferably 0.10 to 1.00, and even more preferably 0.10 to 0.50.

[0060] The first polyolefin resin contained in the core is preferably an propylene resin, and more preferably an propylene homopolymer. The second polyolefin resin contained in the sheath is preferably an propylene resin, and more preferably an propylene-α-olefin copolymer. The preferred forms of the propylene homopolymer and the propylene-α-olefin copolymer are as described above. The value obtained by subtracting the melting point of the second polyolefin resin from the melting point of the first polyolefin resin (i.e., the melting point difference [melting point of the first polyolefin resin - melting point of the second polyolefin resin]) is preferably greater than 0°C, more preferably 5°C or more, more preferably 10°C or more, and particularly preferably 15°C or more. The upper limit of the melting point difference [melting point of the first polyolefin resin - melting point of the second polyolefin resin] is preferably 50°C, more preferably 40°C, and more preferably 30°C.

[0061] The average fiber diameter of the crimped fibers is preferably 10 μm to 30 μm, and more preferably 10 μm to 20 μm. This average fiber diameter is easily achieved when using a spunbonded nonwoven fabric as the synthetic fiber nonwoven fabric for forming the synthetic fiber nonwoven fabric region containing the crimped fibers.

[0062] As a preferred form of the composite nonwoven fabric disclosed herein, the form in which the synthetic fiber nonwoven fabric region is derived from the region of the spunbonded nonwoven fabric (more preferably a spunbonded nonwoven fabric containing crimped fibers) can be cited.

[0063] (Region Originating from SMS Nonwoven Fabric) As a preferred embodiment of the composite nonwoven fabric disclosed herein, a configuration in which the synthetic fiber nonwoven fabric region originates from the SMS nonwoven fabric region can also be cited. Here, the SMS nonwoven fabric refers to a laminated nonwoven fabric containing two spunbond nonwoven fabrics as the outermost layers and at least one meltblown nonwoven fabric disposed between the two spunbond nonwoven fabrics. According to the preferred embodiment, the interweaving of synthetic fibers and crimped fibers is further promoted by the meltblown nonwoven fabric in the SMS nonwoven fabric, resulting in a further increase in peel strength. The SMS nonwoven fabric may contain only one meltblown nonwoven fabric between the two spunbond nonwoven fabrics as the outermost layers, or it may contain two or more. The SMS nonwoven fabric may also contain other spunbond nonwoven fabrics between the two spunbond nonwoven fabrics as the outermost layers. For example, SMS nonwoven fabric can be spunbonded nonwoven fabric / spunbonded nonwoven fabric / meltblown nonwoven fabric / spunbonded nonwoven fabric / spunbonded nonwoven fabric, or it can be spunbonded nonwoven fabric / spunbonded nonwoven fabric / meltblown nonwoven fabric / spunbonded nonwoven fabric.

[0064] The average fiber diameter of the spunbonded nonwoven fabric in SMS nonwoven fabric is, for example, 10 μm to 30 μm. The average fiber diameter of the meltblown nonwoven fabric in SMS nonwoven fabric is, for example, 0.1 μm to 7 μm. The methods for determining the average fiber diameter of the spunbonded nonwoven fabric in SMS nonwoven fabric and the average fiber diameter of the meltblown nonwoven fabric in SMS nonwoven fabric are respectively shown in the examples described later.

[0065] The preferred forms of the spunbonded nonwoven fibers in the SMS nonwoven fabric and the meltblown nonwoven fibers in the SMS nonwoven fabric have been described as preferred forms of synthetic fibers containing polyolefin resins.

[0066] (Applications) Preferred applications of the composite nonwoven fabric disclosed herein include, for example: diapers, sanitary products and other hygiene materials; masks, face masks, makeup remover pads, cosmetic pads and other cosmetic products; wound dressings or surgical pads and other medical pads; cell culture media; apparel products; wig substrates; bedding; food packaging materials; electronic materials, etc. Among these, the composite nonwoven fabric disclosed herein is preferably used in face mask applications requiring softness, strength and liquid retention, especially on the surface of the face mask that comes into contact with the skin.

[0067] [An example of a method for manufacturing composite nonwoven fabric] An example of the method for manufacturing composite nonwoven fabric disclosed herein (hereinafter referred to as Method A) includes: a step of preparing a filament web containing crimped filament fibers as the main component; a step of preparing a synthetic fiber nonwoven fabric containing synthetic fibers comprising a polyolefin resin as the main component; and a step of obtaining a composite nonwoven fabric by interlacing the filament web with the synthetic fiber nonwoven fabric.

[0068] In method A, since a filament web containing crimped filaments as the main component is used, the filament web can be effectively interwoven with the synthetic fiber nonwoven fabric. Therefore, the composite nonwoven fabric disclosed herein can be preferably manufactured.

[0069] The preferred form of the filament web prepared in the step of preparing the filament web can be appropriately referred to the description of the filament region of the composite nonwoven fabric. The step of preparing the filament web can be a step of preparing only a pre-manufactured filament web, or it can be a step of manufacturing the filament web for carrying out method A. In the step of preparing the filament web, only one filament web can be prepared, or multiple filament webs can be prepared. The number of filament webs can be appropriately selected according to the number of filament webs used in the step of obtaining the composite nonwoven fabric.

[0070] In the step of preparing synthetic fiber nonwoven fabric, the preferred form of the synthetic fiber nonwoven fabric can be appropriately referred to the description of the synthetic fiber nonwoven fabric region in the composite nonwoven fabric.

[0071] In manufacturing method A, from the viewpoint of further promoting the interweaving of synthetic fibers and crimped fibers, and thus further improving the peel strength of the obtained composite nonwoven fabric, the synthetic fiber nonwoven fabric prepared in the step of preparing synthetic fiber nonwoven fabric is preferably a spunbonded nonwoven fabric (preferably a spunbonded nonwoven fabric containing crimped fibers) or an SMS nonwoven fabric.

[0072] The step of preparing the synthetic fiber nonwoven fabric can be either a step of preparing only a pre-manufactured synthetic fiber nonwoven fabric, or a step of manufacturing the synthetic fiber nonwoven fabric for carrying out Method A. In the step of preparing the synthetic fiber nonwoven fabric, only one sheet of synthetic fiber nonwoven fabric may be prepared, or multiple sheets of synthetic fiber nonwoven fabric may be prepared. The number of sheets of synthetic fiber nonwoven fabric may be appropriately selected based on the number of sheets of synthetic fiber nonwoven fabric used in the step of obtaining the composite nonwoven fabric.

[0073] The step of obtaining the composite nonwoven fabric is to obtain the composite nonwoven fabric by interlacing at least one silk fiber web with at least one synthetic fiber nonwoven fabric. By this step, the silk fiber web and the synthetic fiber nonwoven fabric are interlaced in three dimensions to integrate them, thereby obtaining a composite nonwoven fabric containing silk regions derived from the silk fiber web and synthetic fiber nonwoven fabric regions derived from the synthetic fiber nonwoven fabric.

[0074] In the step of obtaining the composite nonwoven fabric, it is preferable to interweave the two outermost filament webs and at least one synthetic fiber nonwoven fabric disposed between the two filament webs. In this configuration, the filament webs and the synthetic fiber nonwoven fabric can be arranged alternately.

[0075] The interweaving of the silk fiber web and the synthetic fiber nonwoven fabric is preferably carried out by hydroentangling. When the interweaving of the silk fiber web and the synthetic fiber nonwoven fabric is carried out by hydroentangling, the softness of the silk fibers is more effectively maintained in the composite nonwoven fabric.

[0076] Here, hydroentangling is also known as water-jet interlacing, a process in which the fiber web and the synthetic nonwoven fabric are interlaced by spraying water jets from the upper surface and lower limit side of the laminated body. The water pressure is preferably 0.5 MPa to 10 MPa, more preferably 1 MPa to 8 MPa, and even more preferably 1 MPa to 6 MPa. The water jetting can be continuous or intermittent. Furthermore, in hydroentangling, the conditions and number of water jets sprayed from the upper surface side can be the same as or different from those sprayed from the lower limit side. For example, the process described in International Publication No. 2020 / 036143 can be referred to for hydroentangling. [Example]

[0077] Although the following shows embodiments of the present disclosure, the present disclosure is not limited to the following embodiments.

[0078] [Example 1] <Production of Composite Nonwoven Fabric> (Production of Silk Fiber Web (First and Third Layers)) Commercially available silk fibers (A1 fiber slivers, average fiber diameter 12 μm, manufactured by Hasegawa Shoten Co., Ltd.) were subjected to two mechanical crimping operations using a clamp to obtain bundles of crimped silk fibers (i.e., crimped silk fibers. In Table 1, they are referred to as "crewed fibers"). Here, the average fiber diameter of the silk fibers refers to the average fiber diameter of 30 silk fibers. The fiber diameter of each silk fiber was measured using a scanning electron microscope (Hitachi SU3500 model; 300x magnification).

[0079] As a clamp in the mechanical crimping operation, a funnel-shaped clamp including a tubular portion is used. A single mechanical crimping operation is configured as follows: while the filament is bent into a serrated shape, it is pressed into the tubular portion of the clamp, and the pressed filament is pressed out from the tubular portion in a bundle shape.

[0080] The shape of the crimped filaments in the obtained crimped filament bundle is a repeating sawtooth shape of mountains and valleys. In this sawtooth shape, the crimp spacing, that is, the average distance between the apex of adjacent mountains (more specifically, the average of 30 measurements) is 1.0 mm.

[0081] Next, the crimped filament bundle is cut to an average fiber length of 51 mm. Here, the average fiber length of the crimped filament refers to the average fiber length of 30 crimped filaments. Using the cut crimped filament bundle as raw material, a crimped filament web (more specifically, a crimped filament nonwoven fabric; the same applies below) is produced using a fiber opener and a roller carding machine.

[0082] Through the above operations, a first layer of crimped fiber web with a unit area weight of 13 g / m² and a third layer of crimped fiber web with a unit area weight of 14 g / m² were obtained. Here, the change in unit area weight was achieved by changing the rotation speed of the roller-type parallel carding machine. The method for measuring unit area weight will be described later.

[0083] (Preparation of Synthetic Fiber Nonwoven Fabric (Second Layer)) As raw materials, the following were prepared: a propylene homopolymer with a melting point of 162°C and an MFR (measured according to ASTM D1238 at a temperature of 230°C with a load of 2.16 kg. The same applies hereinafter unless otherwise specified.) of 60 g / 10 min; and a propylene-ethylene random copolymer with a melting point of 142°C, an MFR of 60 g / 10 min, an ethylene unit content of 4.0 mol%, and a propylene unit content of 96.0 mol%. Using these raw materials, a synthetic fiber nonwoven fabric (spunbonded nonwoven fabric in Example 1; referred to as "SB (single layer)") was prepared as the second layer by a spinning-bonding method.

[0084] Specifically, by composite melt spinning, a crimped composite fiber (specifically, an off-core core-sheath type crimped composite fiber) with a core of propylene homopolymer, a sheath of propylene-ethylene random copolymer, and a mass ratio [core / sheath] of 0.25 is obtained. The obtained crimped composite fibers are stacked on a collecting surface, and then embossed at an embossing area ratio of 18% and an embossing temperature of 110°C to obtain a synthetic fiber nonwoven fabric (spunbonded nonwoven fabric) with a unit area weight of 17 g / m2 as a second layer. In the obtained synthetic fiber nonwoven fabric, the average fiber diameter of the crimped composite fibers is 16 μm. The crimped composite fibers (specifically, off-core core-sheath type crimped composite fibers) have a side-by-side cross-sectional shape.

[0085] Ten rectangular test pieces, each 10 mm long and 10 mm wide, were taken from the synthetic fiber nonwoven fabric used as the second layer. Each test piece was observed at 300x magnification using an ECLIPSE E400 microscope manufactured by Nikon. In this observation, 20 crimped composite fibers with a diameter of 9 μm or more were selected from each test piece, and the diameter of each selected crimped composite fiber with a diameter of 9 μm or more was measured in μm to one decimal place. The average of the 200 measured values ​​was calculated as the average fiber diameter of the crimped composite fiber.

[0086] (Production of Composite Nonwoven Fabric) The first layer, the second layer, and the third layer are sequentially overlapped to form a laminate, and the obtained laminate is placed on a web. At this time, the machine direction (MD) of the first layer and the MD of the third layer coincide in directions approximately parallel to the MD of the second layer. Then, while the web and the laminate placed on it are advanced at a speed of 7 m / min, the laminate is subjected to hydroentangling (i.e., water flow weaving treatment). The hydroentangled laminate is then subjected to surface smoothing treatment using clamping rollers, drying treatment at 110°C using a hot air through-type heat treatment machine, and surface smoothing treatment using clamping rollers in sequence to obtain a composite nonwoven fabric as a hydroentangled nonwoven fabric. The hydroentangling process (i.e., water jet weaving process) is implemented by using a water spraying device comprising nozzles with orifices of 0.10 mm diameter spaced 1 mm apart. A columnar water jet at a pressure of 2 MPa, a columnar water jet at a pressure of 4 MPa, and a columnar water jet at a pressure of 4 MPa are sprayed once onto the upper surface of the laminate. Then, a columnar water jet at a pressure of 4 MPa is sprayed once onto the lower surface of the laminate. The distance between the surface of the laminate and the orifices is set to 15 mm.

[0087] <Measurement and Evaluation> The following measurements and evaluations were performed on the composite nonwoven fabric and its materials. The results are shown in Table 1.

[0088] (1)Weight per unit area (g / m2; "gsm" in Table 1) The weight per unit area of ​​the composite nonwoven fabric is determined by taking five 10 cm square rectangular samples from the composite nonwoven fabric and dividing the total mass of the five samples by the total area of ​​the five samples. The weight per unit area of ​​each of the first to third layers is also determined by the same method as the weight per unit area (g / m2) of the composite nonwoven fabric.

[0089] (2) The crimp of the crimped filament fiber is determined by cutting the crimped filament fiber bundle into an average fiber length of 51 mm and taking out a crimped filament fiber bundle X1 with a cross-sectional area of ​​about 1 mm2. The taken out crimped filament fiber bundle X1 is arranged along a scale to minimize undulation. One end of the bundle X1 is held with tweezers, and the bundle X1 is fixed at a position 3.0 cm away from the other end from the position held by the tweezers. Then, the tweezers are pulled towards one end of the bundle X1 by hand at a speed of about 0.5 cm / sec, thereby elongating the portion of the bundle X1 from the fixed position to the position held by the tweezers (i.e., the 3.0 cm long portion as the length before elongation). This operation is performed until it can no longer be stretched by hand (i.e., until the bundle X1 no longer elongates), and the length (cm) of the portion from the fixed position to the position held by the tweezers at this time is measured (hereinafter referred to as "length at elongation"). Repeat this operation 10 times and calculate the average of the 10 measurements as the "average length at elongation (cm)". Using 3.0 cm as the length before elongation and the average length at elongation, calculate the curl (%) using the following formula: Curl (%) = {1 - (3.0 / average length at elongation (cm))} × 100

[0090] (3)Fiber content (mass%) in composite nonwoven fabric The fiber content (mass%) in composite nonwoven fabric is calculated by the following formula: Fiber content (mass%) = {(Unit area weight of the first layer (g / m2) + Unit area weight of the third layer (g / m2)) / Unit area weight of the composite nonwoven fabric (g / m2)} × 100

[0091] (4) Thickness (mm) of the composite nonwoven fabric The thickness of the composite nonwoven fabric was measured using five samples, in the same manner as the measurement of the unit area weight (g / m2) of the composite nonwoven fabric. Specifically, for each of the five samples, the thickness at five points, including the center and four corners, was measured using a thickness gauge (PEACOCK, model "R1-250", measuring terminal 25 mmϕ, load 7 gf / cm2). The average thickness was calculated by arithmetically averaging the 25 measured data points, and this average thickness was taken as the thickness (mm) of the composite nonwoven fabric.

[0092] (5) MD tensile strength of the composite nonwoven fabric: Five rectangular specimens, each 200 mm long and 50 mm wide, were taken from the composite nonwoven fabric. Each of the five specimens was taken in a direction approximately parallel to the MD (mechanical direction) of the second layer of the composite nonwoven fabric along its length. For each specimen, the tensile strength along its length was measured using a tensile testing machine (Shimadzu Corporation, Autograph AGS-J) with a chuck distance of 100 mm and a rod speed of 300 mm / min, according to JIS L 1906. The average of the five measured values ​​was calculated as the MD tensile strength of the composite nonwoven fabric at a width of 50 mm.

[0093] (6)The CD tensile strength of the composite nonwoven fabric will be determined by changing the direction of the five specimens to make the length direction of the specimen approximately parallel to the CD (Cross direction; that is, the direction orthogonal to MD when viewed from above) of the second layer of the composite nonwoven fabric. Otherwise, the CD tensile strength of the composite nonwoven fabric will be determined in the same way as the MD tensile strength of the composite nonwoven fabric.

[0094] (7) Air permeability of the composite nonwoven fabric (ccs (i.e., cm3 / cm2 / sec)) Five rectangular specimens, each 150 mm long and 150 mm wide, were taken from the composite nonwoven fabric. The five specimens were taken in a direction approximately parallel to the MD (mechanical direction) of the second layer of the composite nonwoven fabric along the length of the specimen. For each specimen, the air permeability was measured using a Fragile air permeability tester according to JIS L 1906. The average of the five measured values ​​was calculated as the air permeability of the composite nonwoven fabric.

[0095] (8) The peel strength of the composite nonwoven fabric is used as an indicator of the strength in the thickness direction of the composite nonwoven fabric. The peel strength of the composite nonwoven fabric is measured as follows. Five rectangular specimens with a length of 200 mm and a width of 20 mm were taken from the composite nonwoven fabric. The five specimens were taken in a direction that is approximately parallel to the MD (mechanical direction) of the second layer of the composite nonwoven fabric in the length direction of the specimen. For each specimen, firstly, the second layer side and the third layer side of a 50 mm long area from one end in the length direction were peeled off. Then, the peeled second layer side and the third layer side were fixed to the chuck of the tensile testing machine (Shimadzu Corporation, Autograph AGS-J) with a chuck distance of 50 mm. Then, the second layer side and the third layer side fixed on the chuck were stretched in opposite directions at a rod speed of 100 mm / min, thereby performing a T-shaped peel on the second layer side and the third layer side in the remaining area (a 150 mm long area), and the peel strength at this time was measured. The average of the five measured values ​​was calculated as the peel strength of the composite nonwoven fabric (N / 20 mm width).

[0096] (9)MD stiffness and softness (mm) As one of the indicators of the softness of the composite nonwoven fabric in the MD (mechanical direction), the MD stiffness and softness were measured as follows. Five rectangular specimens with a length of 200 mm and a width of 20 mm were taken from the composite nonwoven fabric. The five specimens were taken in a direction that was approximately parallel to the MD (mechanical direction) of the second layer of the composite nonwoven fabric in terms of the length of the specimen. The stiffness and softness (mm) of each specimen was measured on both the surface and back sides in a constant temperature chamber of 20±2℃ and 65±2% humidity according to JIS L 1096:2010 (method 8.21.1A (45° cantilever method)). The average value of the 10 measured values ​​(i.e., the surface and back sides of the five specimens) was calculated as the MD stiffness and softness (mm). The larger the MD stiffness and softness value, the better the softness of the MD (mechanical direction).

[0097] (10)CD stiffness (mm) As one of the indicators of the softness of the composite nonwoven fabric in the CD (direction orthogonal to the mechanical direction when viewed from above), the CD stiffness was measured as follows. That is, except that the direction in which each sample was taken was changed so that the length direction of the sample was approximately parallel to the CD (mechanical direction) of the second layer of the composite nonwoven fabric, the CD stiffness (mm) was measured in the same way as the MD stiffness. The larger the CD stiffness value, the better the softness in the MD (mechanical direction).

[0098] (11) Skin feel and fit were evaluated as follows. A test piece was taken from the composite nonwoven fabric and applied to the face. The test piece was circular with a diameter of 20 cm. Holes with a diameter of 3 cm were made in the test piece at three locations corresponding to the eyes and nose. Using the test piece, sensory evaluation of skin feel and fit was conducted on three women in their 20s. The test piece was soaked in distilled water for 1 hour, then pulled up, and the remaining water droplets on the surface of the test piece were wiped off with a cotton cloth. The test piece was then applied to the face of the subject, and the subject's perception of skin feel and fit was listened to. The same operation was performed using the curled mesh in Comparative Example 2 described later and the SMS nonwoven fabric (second layer) in Example 4 described later. Based on the listening results from each subject, the skin feel and fit score A for each subject was determined by the following evaluation criteria. The average score A of the three subjects was calculated, and the score for skin feel and fit was determined by rounding the first decimal place of the average.

[0099] -Evaluation Criteria- 5: Feels the same as the skin-like texture and fit as the curled mesh, and this skin-like texture and fit lasts for more than 30 minutes. 4: Feels the same as the skin-like texture and fit as the curled mesh (except for cases meeting rating "5"). 3: Feels the same as the skin-like texture as the curled mesh, but the fit is worse than the curled mesh. 2: Feels worse than the curled mesh, but better than SMS nonwoven fabric. 1: Feels worse than the curled mesh, but the same as SMS nonwoven fabric.

[0100] (12) The moisturizing time during wear is one of the indicators of the liquid retention of the composite nonwoven fabric. The moisturizing time during wear of the composite nonwoven fabric is measured. In the evaluation of skin feel and fit, the time until the test piece is peeled off from the subject's face is measured, and the average value of the measurements of 3 subjects is calculated as the moisturizing time during wear of the composite nonwoven fabric. The longer the moisturizing time during wear of the composite nonwoven fabric, the better the liquid retention of the composite nonwoven fabric.

[0101] [Examples 2 and 3] Except for changing the unit area weight of the first layer and the unit area weight of the third layer as shown in Table 1, the same operations as in Example 1 were performed. The results are shown in Table 1. The change in unit area weight was achieved by changing the rotational speed of the roller-type parallel carding machine.

[0102] 〔Example 4〕 <Production of composite nonwoven fabric〉 (Production of filament web (first layer and third layer)) In the same manner as the production of the first layer in Example 1, a first layer of crimped filament web with a unit area weight of 13 g / m2 and a third layer of crimped filament web with a unit area weight of 13 g / m2 were obtained respectively.

[0103] (Fabrication of Synthetic Fiber Nonwoven Fabric (Second Layer)) As described below, a synthetic fiber nonwoven fabric, designated as the second layer, was fabricated as an SMS nonwoven fabric (i.e., in this embodiment, a nonwoven fabric comprising a spunbond nonwoven fabric layer and one or more meltblown nonwoven fabric layers disposed between the spunbond nonwoven fabric layers). The obtained SMS nonwoven fabric contains fibers from the spunbond nonwoven fabric layer and fibers from the meltblown nonwoven fabric layer. These fibers are all non-crimped fibers.

[0104] Using a propylene homopolymer with an MFR of 60 g / 10 min as raw material, fibers were formed by melt spinning at a melt temperature of 230°C and a spinneret diameter of 0.6 mm. The formed fibers were then deposited on a collecting surface to form a spunbond nonwoven layer S-1 with an average fiber diameter of 16 μm and a unit area weight of 6 g / m2. Next, using a propylene homopolymer with an MFR of 400 g / 10 min as raw material, fibers were formed by meltblowing under the conditions of ejecting melt at a melt temperature of 280°C from a spinneret and blowing heated air at 280°C through the outlet of the spinneret nozzle. The formed fibers were then deposited on the spunbond nonwoven layer S-1 to form a meltblown nonwoven layer M-1 with an average fiber diameter of 3 μm and a unit area weight of 1 g / m2. Next, under the same conditions as the formation of the spunbond nonwoven layer S-1, a spunbond nonwoven layer S-2 is formed on the meltblown nonwoven layer M-1, thereby obtaining a laminated body with a laminated structure having spunbond nonwoven layer S-1, meltblown nonwoven layer M-1, and spunbond nonwoven layer S-2 arranged in sequence. Then, by embossing the obtained laminated body under conditions of 18% embossing area ratio and 145°C embossing temperature, the spunbond nonwoven layer S-1, meltblown nonwoven layer M-1, and spunbond nonwoven layer S-2 are integrated, thereby obtaining a second layer of SMS nonwoven fabric (synthetic fiber nonwoven fabric) with a unit area weight of 13 g / m².

[0105] In Example 4, the area weight of the SMS nonwoven fabric (synthetic fiber nonwoven fabric) was measured in the same manner as the second layer in Example 1. The area weight of the spunbonded nonwoven fabric layer S-1 and the area weight of the meltblown nonwoven fabric layer M-1 were measured using single-layer nonwoven fabrics formed under the same conditions as those layers, and the area weight of the formed single-layer nonwoven fabrics was measured in the same manner as the second layer in Example 1. The average fiber diameter of the spunbonded nonwoven fabric layer S-1 was measured in the same manner as the average fiber diameter of the second layer in Example 1. The average fiber diameter of the meltblown nonwoven fabric layer M-1 was observed using a scanning electron microscope (SU3500 manufactured by Hitachi) at a magnification of 2000x. Specifically, 30 fibers with a fiber diameter of 8 μm or less were selected from the field of view, and the fiber diameter (μm) of the selected 30 fibers was measured. The average fiber diameter of the meltblown nonwoven fabric layer M-1 was calculated by averaging the obtained measurements.

[0106] (Preparation of composite nonwoven fabric) Using the first layer, the second layer and the third layer, a composite nonwoven fabric is prepared in the same manner as the composite nonwoven fabric prepared in Example 1.

[0107] <Measurement and Evaluation> The composite nonwoven fabric and its materials were subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0108] [Example 5] Except for changing the unit area weight of the first layer and the unit area weight of the third layer as shown in Table 1, the same operation as in Example 4 was performed. The results are shown in Table 1. The change in unit area weight was made by changing the rotation speed of the roller-type parallel carding machine.

[0109] 〔Example 6〕 <Production of composite nonwoven fabric〉 (Production of silk fiber web (first layer and third layer)) In the same manner as the production of the first layer and the third layer in Example 1, a first layer with a unit area weight of 13 g / m2 and a third layer with a unit area weight of 14 g / m2 were obtained respectively.

[0110] (Preparation of Synthetic Fiber Nonwoven Fabric (Second Layer)) Using a propylene homopolymer with an MFR of 60 g / 10 min as raw material, fibers were formed by melt spinning at a melt temperature of 230°C and a spinneret length of 0.6 mm. The obtained fibers were then deposited on a collecting surface. Embossing was then performed at an embossing area ratio of 18% and an embossing temperature of 150°C to obtain a spunbonded nonwoven fabric (second layer) with an average fiber diameter of 16 μm and a unit area weight of 17 g / m² (referred to as "SB (single layer)" in Table 1). The fibers in the obtained spunbonded nonwoven fabric are non-crimped fibers.

[0111] (Preparation of composite nonwoven fabric) Using the first layer, the second layer and the third layer, a composite nonwoven fabric is prepared in the same manner as the composite nonwoven fabric prepared in Example 1.

[0112] <Measurement and Evaluation> The composite nonwoven fabric and its materials were subjected to the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0113] [Comparative Examples 1 and 2] Except for changing the unit area weight of the first layer as shown in Table 1, and using the first layer instead of the laminated body of the first, second, and third layers, a single-layer crimped fiber web was made in the same manner as in Example 1. The single-layer crimped fiber web was used to perform the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0114] [Comparative Example 3] An attempt was made to produce a composite nonwoven fabric in the same manner as in Example 1, except that no mechanical crimping operation was performed on the commercially available silk fibers (A1 fiber strips, average fiber diameter 12 μm, manufactured by Hasegawa Shoten Co., Ltd.) (i.e., non-crimped silk fibers). However, it was impossible to interweave the first, second, and third layers, thus making it impossible to produce a composite nonwoven fabric (i.e., the shape retention of the composite nonwoven fabric was significantly insufficient).

[0115] [Comparative Example 4] Except that a second layer was used instead of a laminate in which the first, second, and third layers were overlapped, an SMS nonwoven fabric was prepared in the same manner as in Example 4. The obtained SMS nonwoven fabric was used to perform the same measurements and evaluations as in Example 1. The results are shown in Table 1.

[0116] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Material First layer Main ingredients Curly silk Curly silk Curly silk Curly silk Curly silk Curly silk Curly silk Curly silk Non-curly yarn - Weight per unit area (gsm) 13 10 6.5 13 6.5 13 25 30 13 - Curl 20% 20% 20% 20% 20% 20% 20% 20% 2% - Second floor Material composition SB (Single Layer) SB (Single Layer) SB (Single Layer) SMS SMS SB (Single Layer) - - SB (Single Layer) SMS Main ingredients Compound curl Compound curl Compound curl non-curly non-curly non-curly - - Compound curl non-curly Weight per unit area (gsm) 17 17 17 13 13 17 - - 17 13 Third layer Main ingredients Curly silk Curly silk Curly silk Curly silk Curly silk Curly silk - - Non-curly yarn - Weight per unit area (gsm) 14 10 6.5 13 6.5 14 - - 14 - Curl 20% 20% 20% 20% 20% 20% - - 2% - complex non-woven fabric Interweaving method Spunlace Spunlace Spunlace Spunlace Spunlace Spunlace Spunlace Spunlace Spunlace Spunlace Weight per unit area (gsm) 44 37 30 39 26 44 25 30 - (Cannot be intertwined) 13 Silk content (mass%) 61 54 43 67 50 61 100 100 0 thickness 0.44 mm 0.43 mm 0.39 mm 0.31 mm 0.27 mm 0.40 mm 0.25 mm 0.30 mm 0.23 mm MD tensile strength (N / 50 mm) 36 29 25 36 29 39 16 19 25 CD tensile strength (N / 50 mm) 13 10 8 11 11 15 3 4 12 Breathability 150 ccs 171 ccs 189 ccs 103 ccs 118 ccs 124 ccs 343 ccs 286 ccs 225 ccs Peel strength 0.8 N 0.9 N 0.7 N 1.3 N 1.0 N 0.5 N - - - Flexibility (MD stiffness / softness) 44 mm 42 mm 41 mm 43 mm 42 mm 45 mm 36 mm 37 mm 44 mm Flexibility (CD stiffness / softness) 25 mm 23 mm 21 mm 25 mm 22 mm 26 mm 19 mm 20 mm 32 mm Skin feel and fit 5 5 5 3 3 5 5 5 1 Liquid retention (Moisturizing time when wearing) 30 minutes or more 30 minutes or more 30 minutes or more 23 minutes 21 minutes 30 minutes or more 30 minutes or more 30 minutes or more 1 minute

[0117] As shown in Table 1, the composite nonwoven fabrics of Examples 1 to 6, which include a filament region containing crimped filament fibers as the main component and a synthetic fiber nonwoven fabric region containing synthetic fibers containing polyolefin resin as the main component, exhibit excellent softness, strength (i.e., MD tensile strength, CD tensile strength, and peel strength), and liquid retention. In Comparative Examples 1 and 2, which do not contain synthetic fiber nonwoven fabric regions, the strength is insufficient compared to the examples. Furthermore, in Comparative Example 4, which does not contain filament regions, the liquid retention and softness are insufficient. Additionally, in Comparative Example 3, which uses non-crimped filament fibers instead of crimped filament fibers, compared to Example 1, it is impossible to interweave the layers, thus making it impossible to produce a composite nonwoven fabric.

[0118] In Examples 1 to 6, in Examples 1 to 3 where the synthetic fiber contains crimped fiber, and in Examples 4 and 5 where the synthetic fiber nonwoven fabric area is derived from SMS nonwoven fabric, the peel strength of the composite nonwoven fabric is superior.

[0119] The disclosure of Japanese Patent Application No. 2020-116943, filed on July 7, 2020, is incorporated herein by reference in its entirety. All documents, patent applications and technical specifications described in this specification are incorporated herein by reference to the same extent as those documents, patent applications and technical specifications specifically described and incorporated herein by reference. [Simplified Explanation of the Diagram]

[0121] None

Claims

1. A composite nonwoven fabric, comprising: Two filament regions are configured in the thickness direction of the composite nonwoven fabric, containing crimped filament fibers as the main component; The composite nonwoven fabric includes at least one synthetic fiber nonwoven region disposed between the two filament regions. The synthetic fiber, comprising a polypropylene resin, is incorporated into the filament regions by interweaving. The crimp of the filament fibers is 5%–40%, and the content of the filament fibers relative to the total mass of the composite nonwoven fabric is 40%–70% by mass. The content of the synthetic fiber fibers relative to the total mass of the composite nonwoven fabric is 50% by mass or more. The synthetic fiber nonwoven fabric region originates from a region of spunbonded nonwoven fabric or spunbonded meltblown spunbonded nonwoven fabric. The spunbonded meltblown spunbonded nonwoven fabric comprises two spunbonded nonwoven fabrics as the outermost layers and at least one meltblown nonwoven fabric disposed between the two spunbonded nonwoven fabrics.

2. The composite nonwoven fabric as described in claim 1, having a thickness of 1.00 mm or less.

3. The composite nonwoven fabric as described in claim 1 or claim 2 has a unit area weight of 20 g / m2 to 60 g / m2.

4. The composite nonwoven fabric as described in claim 1 or claim 2, wherein, The tensile strength in the mechanical direction is above 20 N / 50 mm.

5. The composite nonwoven fabric as described in claim 1 or claim 2, wherein, The tensile strength in the direction orthogonal to the machine direction when viewed from above is greater than 5 N / 50 mm.

6. The composite nonwoven fabric as described in claim 1 or claim 2, wherein, The average fiber diameter of the synthetic fiber is 10 μm to 30 μm.

7. The composite nonwoven fabric as described in claim 1 or claim 2, wherein, The synthetic fiber contains crimped fibers.

8. A method for manufacturing a composite nonwoven fabric, comprising: The steps for preparing a silk fiber web containing crimped silk fibers as the main component; The steps include preparing a synthetic fiber nonwoven fabric containing synthetic fibers comprising polypropylene resin as the main component; and obtaining the composite nonwoven fabric by interlacing the filament web with the synthetic fiber nonwoven fabric.

9. The method for manufacturing the composite nonwoven fabric as described in claim 8, wherein, In the step of obtaining the composite nonwoven fabric, the interweaving of the silk fiber web and the synthetic fiber nonwoven fabric is carried out by hydroentangling.