Nylon fibers

Abstract

To provide nylon fibers having excellent tensile strength.　Nylon fibers according to the present disclosure comprises a composition containing nylon, carbon nanotubes, and a dispersant.

Description

Nylon fiber

[0001] This disclosure relates to nylon fibers.

[0002] Nylon fibers are fibers that have various excellent properties such as excellent tensile strength, flexural fatigue resistance, abrasion resistance, are easy to get dirty off, and also have excellent quick-drying properties, and are widely used. For example, nylon fibers are used in various applications such as clothing and industrial materials.

[0003] By the way, Patent Document 1 discloses a resin composition characterized by including a matrix mainly composed of a nylon resin and carbon nanotubes with a content of 10% by mass to 30% by mass and having a limiting PV value of 2.0 MPa·m / s or more. Patent Document 1 discloses that the resin composition has abrasion resistance and mechanical strength.

[0004] [[ID=​​​​​​​​In other words, the present invention relates, for example, to the following [1] to [4]: ​​[1] A nylon fiber comprising a composition comprising nylon, carbon nanotubes, and a dispersant. [2] The nylon fiber according to [1], wherein the mass ratio of the carbon nanotube content to the dispersant content (carbon nanotube:dispersant) of the composition is 1:0.5 to 1:10. [3] The nylon fiber according to [1] or [2], wherein the dispersant is a silicone-based dispersant. [4] The nylon fiber according to any one of [1] to [3], wherein the carbon nanotube content of the composition is 0.01 to 2% by mass.

[0008] According to the present invention, it is possible to provide nylon fibers with excellent tensile strength.

[0009] The upper and / or lower limits of the numerical ranges described herein can be arbitrarily combined to define a preferred range. For example, the upper and lower limits of the numerical ranges can be arbitrarily combined to define a preferred range, the upper limits of the numerical ranges can be arbitrarily combined to define a preferred range, and the lower limits of the numerical ranges can be arbitrarily combined to define a preferred range.

[0010] Throughout this specification, singular expressions should be understood to include the concept of their plural form unless otherwise specified. Therefore, singular articles (for example, "a," "an," and "the" in English) should be understood to include the concept of their plural form unless otherwise specified.

[0011] In this specification, unless otherwise specified, each component may be used independently, individually, or in combination of two or more.

[0012] In this specification, "carbon nanotube" refers to a cylindrical structure made of graphene sheets. Carbon nanotubes are sometimes referred to as "CNTs".

[0013] In this specification, "single-walled carbon nanotube" refers to a carbon nanotube having one layer of tube structure. "Multi-walled carbon nanotube" refers to a carbon nanotube having two or more layers of tube structure, preferably 2 to 20 layers, more preferably 3 to 15 layers.

[0014] <Nylon Fibers> The nylon fibers of this disclosure consist of a composition comprising nylon, carbon nanotubes, and a dispersant. In this specification, "consists of" means "composed of" and not "consists of." That is, the nylon fibers of this disclosure may consist of the composition alone, or may consist of the composition and other components.

[0015] The nylon fibers of this disclosure may be, for example, monofilaments composed of the composition, or multifilaments composed of the composition. The nylon fibers of this disclosure may also be composite fibers such as core-sheath type or side-by-side type. For example, in the case of a core-sheath type composite fiber, the components constituting the core may be composed of the composition, the components constituting the sheath may be composed of the composition, or both the components constituting the core and the components constituting the sheath may be composed of the composition. In the case of a side-by-side type composite fiber, it is sufficient that the composition constituting at least one of them is composed of the composition. Furthermore, there are no particular restrictions on the structure (cross-sectional structure) of the fiber, and it may be circular, elliptical, irregularly shaped (e.g., Y-shaped, X-shaped), or hollow. The nylon fibers of this disclosure may also have a coating layer.

[0016] The fineness of the nylon fiber is, for example, 100 to 1000 dtex, preferably 150 to 900 dtex.

[0017] [Composition] The composition of the present disclosure comprises nylon, carbon nanotubes, and a dispersant. Nylon is also called polyamide, and examples of nylon include aliphatic polyamides and semi-aromatic polyamides. Examples of aliphatic polyamides include polyamide 6, polyamide 66, polyamide 610, polyamide 11, and polyamide 12. Examples of semi-aromatic polyamides include terephthalic acid polyamides such as polyamide 6T and polyamide 9T.

[0018] The amount of nylon contained in the composition is, for example, 90 to 99.99% by mass, preferably 92 to 99.95% by mass, and more preferably 96 to 99.85% by mass. Within this range, nylon fibers with particularly excellent strength can be obtained, which is therefore preferable.

[0019] The carbon nanotubes (CNTs) may be single-walled carbon nanotubes or multi-walled carbon nanotubes with two or more layers. Preferably, the CNTs are multi-walled carbon nanotubes. The number of layers in the multi-walled carbon nanotubes is not particularly limited, but is preferably 2 to 20 layers.

[0020] The average length of the CNTs is preferably 10 to 1000 μm, more preferably 30 to 800 μm, even more preferably 50 to 500 μm, and particularly preferably 100 to 300 μm. Note that this average length of the CNTs refers to the average length of the CNTs used in manufacturing the composition, i.e., the average length of the CNTs as raw materials. The average length of the CNTs can be adjusted, for example, by adjusting the time spent in the CVD method described later, i.e., the CNT growth time.

[0021] The average diameter of the CNTs is preferably 1 to 50 nm, more preferably 3 to 30 nm, and even more preferably 5 to 15 nm. The average diameter of the CNTs can be adjusted, for example, by adjusting the thickness of the catalyst layer and the type of catalyst, as described later.

[0022] The average length and average diameter of a carbon nanotube (CNT) are measured using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). Specifically, ten images of the CNT are obtained using an SEM or TEM. Ten length measurement points are arbitrarily selected from each of the ten images and measured, for a total of 100 lengths. The average length of the CNT is then calculated by arithmetic mean of these 100 length measurements. Similarly, ten diameter measurement points are arbitrarily selected from each of the ten images and measured, for a total of 100 diameter measurements. The average diameter of the CNT is then calculated by arithmetic mean of these 100 diameter measurements.

[0023] The carbon purity of CNTs is preferably 95.0 to 99.999%. The lower limit of carbon purity of CNTs is preferably 96.0%, more preferably 97.0%, even more preferably 98.0%, even more preferably 99.0%, and particularly preferably 99.8%. The upper limit of carbon purity of CNTs may be, for example, 99.99% or 99.9%. The carbon purity of CNTs can be determined, for example, by elemental analysis using X-ray fluorescence.

[0024] The crystallinity of carbon nanotubes (CNTs) can be evaluated, for example, using Raman spectroscopy. In Raman spectroscopy, the D / G ratio is used as an indicator. The D / G ratio is the value at 1580 cm⁻¹ in the Raman spectrum measured by Raman spectroscopy. -1 1360 cm⁻¹ relative to the peak intensity of the G-band appearing in the vicinity -1 This is the ratio of the peak intensities of the D-band that appear in the vicinity. A smaller D / G ratio indicates higher crystallinity of the carbon nanotube. The D / G ratio in CNTs is preferably 0.5 to 1.0, more preferably 0.6 to 0.8.

[0025] The carbon purity and crystallinity of the CNTs can be adjusted, for example, by adjusting the thickness of the buffer layer in the catalyst substrate, the type of material used in the buffer layer, the thickness of the catalyst layer, the type of catalyst, the type and flow rate of the raw material gas in the CVD method, and the temperature and pressure in the reaction chamber, as described later.

[0026] CNTs can be manufactured using conventionally known methods. For example, CNTs can be manufactured using chemical vapor deposition (CVD) methods such as thermochemical vapor deposition (thermal CVD), plasma CVD, laser ablation, arc discharge, or combustion. Among the CVD methods, thermal CVD is preferred.

[0027] The CVD method involves placing a catalyst substrate, which has a catalyst layer provided on a substrate, into a reaction chamber, supplying a raw material gas to the reaction chamber, and growing CNTs as a CNT forest on the surface of the catalyst layer. A CNT forest refers to an aggregate of multiple CNTs provided on a substrate and oriented perpendicular to the surface of the substrate. In a CNT forest, multiple CNTs stand upright on the substrate. The average length and average diameter of the CNTs in the CNT forest are, for example, the same as the average length and average diameter of the CNTs described above. CNT powder is obtained by scraping the CNT forest from the substrate. CNT powder means powder containing multiple CNTs.

[0028] Examples of substrates include silicon substrates, alumina substrates, magnesium oxide substrates, glass substrates, sapphire substrates, and stainless steel substrates.

[0029] The catalyst layer can be formed, for example, by attaching catalyst particles to a substrate by sputtering. Examples of catalysts include metals, specifically iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), gold (Au), and alloys containing at least one metal selected from the group consisting of these. Examples of alloys include iron alloys, nickel alloys, and cobalt alloys. The catalyst may also be a metal precursor, such as a metal oxide or metal compound. Examples of metal oxides include iron oxide, nickel oxide, and cobalt oxide. An example of a metal compound is iron chloride. When using a precursor, it is necessary to convert the precursor to a metal before performing the CVD method by heating or other means.

[0030] The catalyst substrate described above may further include a buffer layer between the substrate and the catalyst layer. The buffer layer can be formed, for example, by sputtering. Examples of materials used for the buffer layer include silica (SiO2), alumina (Al2O3), silicon nitride (SiN), zinc oxide (ZnO), copper oxide (Cu2O), and nickel oxide (NiO).

[0031] Sputtering for forming a catalyst layer and sputtering for forming a buffer layer can be carried out using known equipment and conditions depending on the object to be sputtered. The pressure conditions for sputtering are, for example, about 0.001 to 100 Pa.

[0032] As the raw material gas, carbon-containing raw material gases can be used, and examples include hydrocarbons, sulfur-containing organic gases, phosphorus-containing organic gases, carbon monoxide, and alcohols. Examples of hydrocarbons include alkane compounds such as methane and ethane, alkene compounds such as ethylene and butadiene, alkyne compounds such as acetylene, aryl hydrocarbon compounds such as benzene, toluene, and styrene, aromatic hydrocarbons having condensed rings such as indene, naphthalene, and phenanthrene, cycloalkane compounds such as cyclopropane and cyclohexane, cycloolefin compounds such as cyclopentene, and alicyclic hydrocarbon compounds having condensed rings such as steroids. Examples of alcohols include methanol and ethanol. From the viewpoint of the carbon purity of the resulting CNTs, the raw material gas is preferably hydrocarbons.

[0033] Along with the raw material gas, a carrier gas, which is a gas that transports the raw material gas, may also be supplied to the reaction chamber. Examples of carrier gases include helium, neon, argon, nitrogen, and hydrogen.

[0034] In the CVD method, the temperature in the reaction chamber is, for example, 550 to 900°C, from the viewpoint of the growth rate of CNTs and the carbon purity of the resulting CNTs.

[0035] The pressure inside the reaction chamber in the CVD process may be atmospheric pressure, reduced pressure, or pressurized pressure.

[0036] The amount of CNTs contained in the composition is 0.01 to 2% by mass, preferably 0.03 to 1% by mass, more preferably 0.05 to 0.8% by mass, and particularly preferably 0.05 to 0.5% by mass. Within this range, nylon fibers with particularly excellent strength can be obtained, which is preferable.

[0037] Examples of dispersants include liquid polymers, unvulcanized rubber, thermoplastic elastomers, surfactants, and resin-type dispersants. Examples of liquid polymers include silicone-based dispersants, polyalkylene glycols, polyglycols, polycarbonate polyols, polyester polyols, and polyether polyols. These may be used individually or in combination of two or more. From the viewpoint of dispersibility of CNTs in the resulting composition, the dispersant is preferably at least one selected from silicone-based dispersants, surfactants, and resin-type dispersants, and more preferably at least one selected from silicone-based dispersants.

[0038] Examples of silicone-based dispersants include silicone oils. Examples of silicone oils include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxy-modified silicone oil, carbinol-modified silicone oil, polyether-modified silicone oil, alkyl-modified silicone oil, and fluorine-modified silicone oil. Dimethyl silicone oil is preferred as the silicone-based dispersant.

[0039] Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of anionic surfactants include fatty acid salts, polysulfonates, polycarboxylates, alkyl sulfates, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl phosphates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylaryl ether sulfates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphate sulfonates, glycerol borate fatty acid esters, and polyoxyethylene glycerol fatty acid esters. Specifically, examples include sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene nonylphenyl ether sulfate, and sodium salts of β-naphthalene sulfonic acid formalin condensates.

[0040] Examples of cationic surfactants include alkylamine salts and quaternary ammonium salts. Specifically, these include stearylamine acetate, trimethyl coconut ammonium chloride, trimethyl beef tallow ammonium chloride, dimethyl dioleyl ammonium chloride, methyl oleyl diethanol chloride, tetramethyl ammonium chloride, laurylpyridinium chloride, laurylpyridinium bromide, laurylpyridinium disulfate, cetylpyridinium bromide, 4-alkyl mercaptopyridine, poly(vinylpyridine)-dodecyl bromide, and dodecylbenzyltriethylammonium chloride. Examples of amphoteric surfactants include aminocarboxylate salts.

[0041] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyalkylene derivatives, polyoxyethylene phenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and alkyl allyl ethers. Specifically, polyoxyethylene lauryl ether, sorbitan fatty acid ester, and polyoxyethylene octyl phenyl ether can be mentioned.

[0042] Examples of resin type dispersants include fluororesins, cellulose derivatives, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, hydrogenated nitrile butadiene rubber, and polyacrylonitrile polymers. Examples of cellulose derivatives include cellulose acetate, cellulose acetate butyrate, cellulose butyrate, cyanoethyl cellulose, ethyl hydroxyethyl cellulose, nitrocellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose.

[0043] From the viewpoint of the dispersibility of CNTs in the resulting composition, the mass ratio of the content of carbon nanotubes to the content of the dispersant in the composition (carbon nanotubes: dispersant) is preferably 1:0.5 to 1:10, more preferably 1:0.7 to 1:7, still more preferably 1:1 to 1:5, and particularly preferably 1:1.5 to 1:3.

[0044] The composition may further contain components other than nylon, CNTs, and the dispersant (hereinafter also referred to as "other components"). Examples of other components include fibrous fillers, powdery fillers, and resin additives. Examples of fibrous fillers include carbon fibers, organic fibers, metal fibers, and glass fibers. Examples of resin additives include antioxidants, heat stabilizers, light stabilizers, weather stabilizers, hydrolysis inhibitors, plasticizers, colorants, flame retardants, foaming agents, nucleating agents, pigments, lubricants, and spreading agents. One kind of other component may be used, or two or more kinds may be used.

[0045] The composition of the present disclosure includes nylon, carbon nanotubes, and a dispersant. The composition may be produced by melt-kneading nylon, carbon nanotubes, and a dispersant. However, from the perspective of more uniformly dispersing carbon nanotubes in the composition and improving the strength of nylon fibers, it is preferable to prepare a composite containing carbon nanotubes and a dispersant and melt-knead the composite and nylon to produce the composition. Melt-kneading is performed, for example, using a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, or a roll mill. The composition obtained by melt-kneading may be recovered as pellets or the like, and then nylon fibers may be produced using the pellets or the like, or nylon fibers may be directly produced from the composition obtained by melt-kneading.

[0046] As a method for producing a composite containing carbon nanotubes and a dispersant, for example, a method having a step of kneading CNT and a dispersant with a three-roll mill can be mentioned. In the step of kneading CNT and a dispersant with a three-roll mill, CNT and a dispersant may be added to the three-roll mill simultaneously or alternately. A mixture of CNT and a dispersant prepared in advance may be added to the three-roll mill.

[0047] In the step of kneading CNT and a dispersant with a three-roll mill, it is preferable to knead for more than 10 minutes after adding CNT and a dispersant to the three-roll mill, more preferably for 20 minutes or more, even more preferably for 30 minutes or more, and particularly preferably for 45 minutes or more. The kneading time after adding CNT and a dispersant to the three-roll mill is, for example, 3 hours or less.

[0048] The rotational speed of the three rolls is preferably 50 to 1000 rpm, more preferably 100 to 900 rpm, and even more preferably 150 to 800 rpm. The distance between the loading roll and the intermediate roll in the three-roll mill is preferably 5 to 200 μm, more preferably 7 to 150 μm, and even more preferably 10 to 100 μm. The distance between the intermediate roll and the finishing roll in the three-roll mill is preferably 5 to 200 μm, more preferably 7 to 150 μm, and even more preferably 10 to 100 μm.

[0049] In the process of mixing CNTs and a dispersant in a three-roll mill, it is preferable to narrow the distance between the loading roll and the intermediate roll in the three-roll mill at regular intervals. Narrowing the distance between the loading roll and the intermediate roll at regular intervals may be done multiple times. When narrowing the distance between the loading roll and the intermediate roll at regular intervals is done multiple times, the distance at the start and end of each round may be different. In addition, the distance between the loading roll and the intermediate roll may be widened after it has been narrowed once.

[0050] Nylon fibers can be produced by spinning the composition. A common spinning method is melt spinning. When melt spinning, for example, the composition is heated to a molten state, extruded from a nozzle, solidified (cooled and solidified), the solidified composition is stretched, and heating and stretching are repeated as needed to obtain nylon fibers of the desired fineness. That is, one embodiment of the nylon fibers of this disclosure is a nylon fiber obtained by obtaining a composite of carbon nanotubes and a dispersant, obtaining a composition by melt-kneading the composite with nylon, and melt-spinning the composition. The disclosure also includes a method for producing nylon fibers, comprising the steps of obtaining a composite of carbon nanotubes and a dispersant, obtaining a composition by melt-kneading the composite with nylon, and obtaining nylon fibers by melt-spinning the composition.

[0051] The nylon fibers of this disclosure have significantly improved tensile strength compared to fibers manufactured from raw materials (nylon or compositions) having a similar composition except for the absence of carbon nanotubes and dispersants, and can therefore be used in various fields where strength is required. Since tensile strength also differs depending on the fineness, it can be compared, for example, by the value obtained by dividing strength (cN) by fineness (dtex) (cN / dtex). The nylon fibers of this disclosure preferably have a cN / dtex improvement of 10% or more compared to fibers manufactured from raw materials (nylon or compositions) having a similar composition except for the absence of carbon nanotubes and dispersants, more preferably an improvement of 20% or more, and particularly preferably an improvement of 30% or more. There is no particular upper limit, but for example it is 100%. The nylon fibers of this disclosure can be used, for example, in sports equipment such as badminton strings, tennis strings, and sportswear, clothing, household goods such as carpets and rugs, automotive applications such as airbags and car mats, and industrial applications.

[0052] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0053] [Manufacturing Example 1] (Manufacturing of a Carbon Nanotube Forest) A wafer (substrate) coated with a catalyst for carbon nanotube growth was prepared, and vertically oriented carbon nanotubes were grown from the catalyst by chemical vapor deposition to produce a vertically oriented carbon nanotube forest oriented perpendicular to the wafer. The carbon nanotubes constituting the carbon nanotube forest were multi-walled carbon nanotubes, with an average length of 250 μm per nanotube, an average diameter of 6 to 10 nm, a carbon purity of 99.8% or higher, and a crystallinity (D / G ratio) of 0.6 to 0.8.

[0054] (Manufacturing of carbon nanotubes) Approximately 0.6 g of carbon nanotube forest formed on a wafer was scraped off the wafer using a scraper to obtain carbon nanotube powder. The same procedure was repeated to prepare the amount of carbon nanotube powder required for the example.

[0055] [Manufacturing Example 2] (Preparation of Composite) 10 g of the above carbon nanotube powder and 20 g of silicone oil (Shin-Etsu Silicone, KF-96-1,000CS, dimethyl silicone oil) were mixed together by adding small amounts alternately between the loading roll and the intermediate roll of a three-roll mill (manufactured by Shenzhen Zhongyi Technology Co., Ltd., ZYTR-80E) over 20 minutes until the total amount was added. The three-roll mill was set to have a gap of 50 μm between the loading roll and the intermediate roll, a gap of 74 μm between the intermediate roll and the finishing roll, and a rotation speed of 300 rpm.

[0056] During mixing, when the mixture appeared on the doctor blade, it was repeatedly returned to the space between the feed roll and the intermediate roll, while the silicone oil was used to cohesive the powdered carbon nanotubes. After mixing for approximately 20 minutes, the gap between the feed roll and the intermediate roll was reduced to 40 μm to further improve cohesion, and mixing was continued for another 20 minutes.

[0057] To eliminate uneven mixing, the gap between the preparation roll and the intermediate roll was set to 15 μm, and the gap between the intermediate roll and the finishing roll was also set to 15 μm, with the aim of removing all the mixed material from the rolls in one go. As a result, almost all of the mixed material inside the rolls came out onto the doctor blade.

[0058] After removing all of the mixed material, it was put back between the input roll and the intermediate roll and mixed again. During mixing, the gap between the input roll and the intermediate roll was narrowed by 10 μm every 5 minutes, from 70 μm to 30 μm. The gap between the intermediate roll and the finishing roll was 15 μm. Then the gap between the input roll and the intermediate roll was widened from 30 μm to 50 μm, and the mixing state was checked by visually inspecting for unevenness in the blackness of the mixed material. After that, mixing was performed again. During mixing, the gap between the input roll and the intermediate roll was narrowed by 10 μm every 5 minutes, from 50 μm to 30 μm.

[0059] Ultimately, a continuous, uniformly black composite film was obtained. The time required from the start of adding carbon nanotube powder and silicone oil to the three-roll mill until the composite film was obtained was approximately 80 minutes. The obtained composite film could be easily broken down by external force. The same procedure was repeated to obtain 30 g of composite film.

[0060] [Example 1] (Preparation of composition) Polyamide 6 (PA6) (LIBOLON N150-300) and the composite (composite film) obtained in Production Example 2 were melt-kneaded using a twin-screw extruder so that the proportion of carbon nanotubes was 0.10% by mass, the proportion of silicone oil was 0.20% by mass, and PA6 was 99.7% by mass, based on 100% by mass of the composition, to obtain pellets of the composition.

[0061] (Preparation of Nylon Fibers) The composition pellets were melt-spun at a cylinder temperature of 270°C in an extruder equipped with a gear pump at the tip of a single-screw extruder with a cylinder diameter of 40 mm and a full-flight screw with an L / D ratio of 27. After cooling and solidifying in a cooling water bath at a water temperature of 15°C, the material was subjected to moist heat stretching to 3.5 times its original size at 97°C and 100% RH. Next, it was stretched in a hot air stretching tank at 180°C, and then in a hot air stretching tank at 190°C to obtain nylon fibers (monofilaments). By changing the stretching ratio in the hot air stretching tank, nylon fibers of 746 dtex, 494 dtex, and 302 dtex were obtained.

[0062] [Comparative Example 1] (Preparation of Nylon Fibers) The procedure was carried out in the same manner as in Example 1, except that the pellets of the composition in Example 1 were replaced with pellets of PA6 (N150-300 manufactured by LIBOLON), and nylon fibers with a density of 741 dtex were obtained.

[0063] [Tensile Strength] The tensile strength of the nylon fibers produced in Example 1 and Comparative Example 1 was measured in accordance with JIS R 7606. The results are shown in Table 1.

[0064]

[0065] From Table 1 above, it was confirmed that the nylon fibers of this disclosure have excellent tensile strength.

Claims

1. A nylon fiber comprising a composition containing nylon, carbon nanotubes, and a dispersant.

2. The nylon fiber according to claim 1, wherein the mass ratio of the carbon nanotube content to the dispersant content (carbon nanotube:dispersant) of the composition is 1:0.5 to 1:

10.

3. The nylon fiber according to claim 1, wherein the dispersant is a silicone-based dispersant.

4. The nylon fiber according to claim 1, wherein the carbon nanotube content of the composition is 0.01 to 2% by mass.

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