Treatment agent for producing carbon fiber-containing non-woven fabric, carbon fiber-containing non-woven fabric, and method for producing carbon fiber-containing non-woven fabric

Abstract

To provide: a treatment agent for producing a carbon fiber-containing non-woven fabric that can reduce breaking in carbon fibers; a carbon fiber-containing non-woven fabric; and a method for producing the carbon fiber-containing non-woven fabric.SOLUTION: The treatment agent for producing the carbon fiber-containing non-woven fabric contains an epoxy compound (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a treatment agent for producing a carbon fiber-containing nonwoven fabric, a carbon fiber-containing nonwoven fabric having such a treatment agent adhered thereto, and a method for producing a carbon fiber-containing nonwoven fabric using such a treatment agent. [Background technology]

[0002] In general, carbon fibers are widely used in various fields such as building materials and transportation equipment as carbon fiber composite materials combined with a matrix resin such as an epoxy resin or as flame-retardant / flame-resistant materials. For example, carbon fibers are produced through a process of spinning, for example, acrylic fiber as a carbon fiber precursor, a fiber drawing process, a flame-retardant process, and a carbonization process.

[0003] Carbon fibers are sometimes used in the form of woven fabrics, as well as nonwoven fabrics obtained using a roller card (carding machine). When producing nonwoven fabrics, a treatment is sometimes carried out to attach a nonwoven fabric treating agent to the surface of the raw fiber in order to impart various properties such as carding properties to the raw fiber. A treating agent disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6184668 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the carbon fibers to which the treatment agent has been applied pass through a carding machine, the carbon fibers may break. Therefore, there has been a demand for a treatment agent for producing a carbon fiber-containing nonwoven fabric that has a further improved effect of reducing the breakage of carbon fibers. [Means for solving the problem]

[0006] As a result of research conducted by the present inventors to solve the above problems, they found that a composition in which an epoxy compound (A) is blended is suitable for a treatment agent for producing a carbon fiber-containing nonwoven fabric. Various aspects for solving the above problems will be described.

[0007] The treatment agent for producing the carbon fiber-containing nonwoven fabric of the first embodiment is an epoxy compound (A). and the following ester compound (C): Contains The treatment agent for producing a carbon fiber-containing nonwoven fabric is characterized in that the epoxy compound (A) has at least one compound selected from bisphenol A, bisphenol F, and diaminediphenylmethane as a main skeleton, and the content of the ester compound (C) in the nonvolatile matter of the treatment agent is 3 to 60 mass%. It is characterized by the following.

[0008] Ester compound (C): An ester compound consisting of a monohydric aliphatic alcohol and a monocarboxylic acid. Aspects 2 is the aspect 1 In the treating agent for producing a carbon fiber-containing nonwoven fabric described in 1. above, the epoxy compound (A) has at least one skeleton selected from a bisphenol A skeleton and a bisphenol F skeleton.

[0009] Aspects 3 is the aspect 1 or 2 In the treating agent for producing a carbon fiber-containing nonwoven fabric described in 1. above, the content of the epoxy compound (A) in the nonvolatile content of the treating agent is 5 to 90 mass %. Aspects 4 is the aspect Any one of 1 to 3 The treating agent for producing a carbon fiber-containing nonwoven fabric described in 1. further contains a nonionic surfactant (B), and the content of the nonionic surfactant (B) in the nonvolatile content of the treating agent is 5 to 60 mass %.

[0010] Aspects 5 The treating agent for producing a carbon fiber-containing nonwoven fabric according to the first aspect further comprises a nonionic surfactant (B )of When the total content of the epoxy compound (A), the nonionic surfactant (B), and the ester compound (C) is taken as 100 mass%, the epoxy compound (A) is contained in an amount of 5 to 90 mass%, the nonionic surfactant (B) is contained in an amount of 5 to 60 mass%, and the ester compound (C) is contained in an amount of 5 to 50 mass%.

[0011] status Mr. 6The carbon fiber-containing nonwoven fabric is 5 The treatment agent according to any one of the above aspects is attached to the surface of the substrate. Aspects 7 The method for producing the carbon fiber-containing nonwoven fabric is as follows: 5 The method is characterized by comprising a step of adhering the treatment agent according to any one of the above aspects to short carbon fibers. [Effects of the Invention]

[0012] According to the present invention, breakage of carbon fibers to which a treatment agent for producing a carbon fiber-containing nonwoven fabric has been applied can be reduced. DETAILED DESCRIPTION OF THE INVENTION

[0013] First Embodiment A first embodiment of the treating agent for producing a carbon fiber-containing nonwoven fabric (hereinafter referred to as the treating agent) of the present invention will be described below. The treating agent of this embodiment contains the following epoxy compound (A): and ester compounds (C) and further contains a nonionic surfactant (B )of It may contain.

[0014] (Epoxy compound (A)) The epoxy compound (A) is a compound having an epoxy group in the molecule. The epoxy compound (A) may be either a monoepoxy compound having one epoxy group in the molecule or a multifunctional epoxy compound having two or more epoxy groups in the molecule.

[0015] The main chain may be, for example, diphenylmethane, more specifically, bisphenol. Specific examples of bisphenol include bisphenol A, AP, AF, B, BP, C, E, F, G, M, S, P, PH, TMC, and Z. Among these, from the viewpoint of further reducing breakage of carbon fibers, the epoxy compound (A) is preferably one having a bisphenol A skeleton and a bisphenol F skeleton.

[0016] In the present invention, the epoxy compound (A) used has at least one main skeleton selected from bisphenol A, bisphenol F, and diaminediphenylmethane. Hereinafter, compounds other than the epoxy compound (A) of the present invention will be referred to as reference examples.

[0017] Specific examples of the epoxy compound (A) include amine-type epoxy compounds such as polymers of polyoxyalkylene-added p-tert-butylphenol monoglycidyl ether, bisphenol A diglycidyl ether, resorcinol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, alkyl glycidyl ether, polyoxyalkylene-added alkyl glycidyl ether, phenyl glycidyl ether, polyoxyalkylene-added phenyl glycidyl ether, triglycidylamine, and tetraglycidylamine.

[0018] Commercially available epoxy compounds (A) may also be used. Specific examples of commercially available epoxy compounds include jER828 (manufactured by Mitsubishi Chemical Corporation), jER834 (manufactured by Mitsubishi Chemical Corporation), jER1001 (manufactured by Mitsubishi Chemical Corporation), jER1002 (manufactured by Mitsubishi Chemical Corporation), Epotohto YD-128 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), Epotohto YD-011 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), Epotohto YD-012 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), Sumiepoxy ELM-434 (manufactured by Sumitomo Chemical Co., Ltd.), and EPICRON N-660 (manufactured by DIC Corporation).

[0019] These epoxy compounds (A) may be used singly or in appropriate combination of two or more. The content of the epoxy compound (A) in the non-volatile content of the treating agent is preferably 3 to 100% by mass, more preferably 5 to 90% by mass. By specifying this range, the effects of the present invention can be further improved. It is also possible to envision a range that arbitrarily combines the above upper and lower limits. Furthermore, the non-volatile content refers to the treating agent that has been heat-treated at 105°C for 2 hours to thoroughly remove volatile components. Hereinafter, the same conditions will be used to define the non-volatile content.

[0020] (Nonionic surfactant (B)) The treatment agent may further contain a nonionic surfactant (B). By including the nonionic surfactant (B) in the treatment agent, the strength of the nonwoven fabric obtained from the carbon fibers to which the treatment agent has been applied is improved.

[0021] Examples of the nonionic surfactant (B) include compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to alcohols or carboxylic acids, ether / ester compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to an ester compound of carboxylic acids and polyhydric alcohol, compounds in which alkylene oxide is added to natural fats and oils or compounds in which such compounds are esterified with carboxylic acids, amine compounds such as compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to primary organic amines, compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to fatty acid amides, amide compounds in which an amine compound and carboxylic acids are condensed, and partial ester compounds of carboxylic acids and polyhydric alcohols, etc.

[0022] Specific examples of alcohols used as raw materials for the nonionic surfactant (B) include, for example, (1) linear alkyl alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, nonacosanol, and triacontanol; (2) isopropanol, isobutanol, isohexanol, 2-ethylhexanol, isononanol, isodecanol, isododecanol, isotridecanol, isotetradecanol, isotriacontanol, and isoheptacontanol; (3) linear alkenyl alcohols such as tetradecenol, hexadecenol, heptadecenol, octadecenol, and nonadecenol; (4) branched alkenyl alcohols such as isohexadecenol and isooctadecenol; (5) cyclic alkyl alcohols such as cyclopentanol and cyclohexanol; and (6) aromatic alcohols such as phenol, nonylphenol, benzyl alcohol, monostyrenated phenol, distyrenated phenol, and tristyrenated phenol.

[0023] Specific examples of carboxylic acids used as raw materials for the nonionic surfactant (B) include: (1) linear alkyl carboxylic acids such as octylic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, and docosanoic acid; (2) branched alkyl carboxylic acids such as 2-ethylhexanoic acid, isododecanoic acid, isotridecanoic acid, isotetradecanoic acid, isohexadecanoic acid, and isooctadecanoic acid; (3) linear alkenyl carboxylic acids such as octadecenoic acid, octadecadienoic acid, and octadecatrienoic acid; (4) aromatic carboxylic acids such as benzoic acid; and (5) hydroxycarboxylic acids such as ricinoleic acid.

[0024] The alkylene oxide used as a raw material for forming the (poly)oxyalkylene structure of the nonionic surfactant (B) is preferably an alkylene oxide having 2 to 4 carbon atoms. Specific examples of alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. The number of moles of alkylene oxide added is appropriately set, but is preferably 0.1 to 150 moles, more preferably 1 to 100 moles, and even more preferably 2 to 50 moles. Any combination of the above upper and lower limits is also possible. The number of moles of alkylene oxide added refers to the number of moles of alkylene oxide per mole of the compound to be added in the raw material. One type of alkylene oxide may be used alone, or two or more types of alkylene oxides may be used in appropriate combination. When two or more types of alkylene oxides are used, the addition form may be any of block addition, random addition, or a combination of block addition and random addition, and is not particularly limited.

[0025] Specific examples of polyhydric alcohols used as raw materials for the nonionic surfactant (B) include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, glycerin, diglycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, trimethylolpropane, sorbitan, pentaerythritol, and sorbitol.

[0026] Specific examples of the aliphatic amine or primary organic amine used as a raw material for the nonionic surfactant (B) include methylamine, ethylamine, butylamine, octylamine, laurylamine, octadecylamine (stearylamine), octadecenylamine, and coconut amine.

[0027] Specific examples of fatty acid amides used as raw materials for the nonionic surfactant (B) include octylic acid amide, lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, behenic acid amide, lignoceric acid amide, amides of fatty acids and diethanolamine, and amides of fatty acids and ethyleneamine.

[0028] These nonionic surfactants (B) may be used singly or in appropriate combination of two or more. The content of the nonionic surfactant (B) in the nonvolatile content of the treatment agent is preferably 3 to 70 mass %, more preferably 5 to 60 mass %. By specifying the content within this range, the strength of the nonwoven fabric obtained from the carbon fiber to which the treatment agent is applied is improved. Note that ranges that combine the above upper and lower limits are also contemplated.

[0029] (Ester compound (C)) The ester compound (C) used in the treatment agent of this embodiment is an ester compound composed of a monohydric aliphatic alcohol and a monocarboxylic acid. By using this ester compound (C), the strength of the nonwoven fabric obtained from the carbon fiber to which the treatment agent has been applied is improved.

[0030] The monocarboxylic acid constituting the ester compound (C) may be a saturated aliphatic carboxylic acid or an unsaturated aliphatic carboxylic acid, and may be a straight-chain or branched-chain carboxylic acid.

[0031] Specific examples of saturated aliphatic carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid (caproic acid), octylic acid (2-ethylhexanoic acid), octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), isooctadecanoic acid (isostearic acid), eicosanoic acid (arachidic acid), docosanoic acid (behenic acid), and tetracosanoic acid.

[0032] Specific examples of unsaturated aliphatic carboxylic acids include crotonic acid, myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, eicosenoic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, and arachidonic acid.

[0033] Specific examples of the monohydric aliphatic alcohol include the specific examples of the monohydric aliphatic alcohols among the alcohols used as raw materials for the nonionic surfactant (B) described above. These ester compounds (C) may be used singly or in combination of two or more.

[0034] The content of the ester compound (C) in the non-volatile matter of the treatment agent is 、3 ~60% by mass , goodThe content is preferably 5 to 50 mass%. By specifying the content range as described above, the strength of the nonwoven fabric obtained from the carbon fiber to which the treatment agent is applied is improved. Note that ranges that combine the above upper and lower limits are also contemplated.

[0035] When the total content of the epoxy compound (A), nonionic surfactant (B), and ester compound (C) in the treatment agent is taken as 100% by mass, it is preferable that the epoxy compound (A) be contained in an amount of 5 to 90% by mass, the nonionic surfactant (B) be contained in an amount of 5 to 60% by mass, and the ester compound (C) be contained in an amount of 5 to 50% by mass. By specifying the content ranges as described above, the effects of the present invention can be further improved. Note that ranges that combine the above upper and lower limits are also contemplated.

[0036] Second Embodiment Next, a second embodiment of the carbon fiber-containing nonwoven fabric (hereinafter simply referred to as nonwoven fabric) according to the present invention will be described. The nonwoven fabric of this embodiment has the treatment agent of the first embodiment adhered to the nonwoven fabric. The nonwoven fabric of this embodiment is manufactured by first adhering the treatment agent of the first embodiment to carbon fibers, followed by a web formation step by carding. There are no particular restrictions on the amount of treatment agent adhered to the nonwoven fabric, but the treatment agent (not including the solvent) is preferably adhered to the nonwoven fabric in an amount of 0.01 to 10 mass %, more preferably 0.1 to 2 mass %.

[0037] The type of carbon fiber constituting the nonwoven fabric is not particularly limited, but examples include PAN-based fibers obtained from acrylic fibers, pitch-based fibers obtained from pitch, recycled carbon fibers extracted from carbon fiber composite materials by chemical decomposition or pyrolysis, polyester fibers, and carbon fibers obtained from polyethylene resins, phenolic resins, cellulose resins, lignin resins, etc. For example, when acrylic fibers are used, the acrylic fibers are preferably composed of fibers whose main component is polyacrylonitrile obtained by copolymerizing at least 90 mol% or more of acrylonitrile with 10 mol% or less of a flame retardant-promoting component. Examples of suitable flame retardant-promoting components include vinyl group-containing compounds copolymerizable with acrylonitrile. The single fiber fineness of the raw fiber is not particularly limited, but is preferably 0.1 to 2.0 dTex from the viewpoint of balancing performance and production costs. The number of single fibers constituting the fiber bundle of the raw fiber is also not particularly limited, but is preferably 1,000 to 96,000 from the viewpoint of balancing performance and production costs.

[0038] In the method for producing carbon fiber according to the present embodiment, first, the raw fiber described above is obtained, and then a spinning process is carried out. Next, a flame-resistant treatment process is carried out in which the fiber bundle produced in the spinning process is converted into a flame-resistant fiber in an oxidizing atmosphere at 200 to 300°C, preferably 230 to 270°C. When further producing carbon fiber, a carbonization process is carried out in which the flame-resistant fiber is further carbonized in an inert atmosphere at 300 to 2000°C, preferably 300 to 1300°C. The carbonization process may be carried out subsequent to the flame-resistant treatment process.

[0039] As described above, the method for producing a nonwoven fabric according to this embodiment first involves the step of adhering the treatment agent of the first embodiment to carbon fibers. The method for adhering the treatment agent to carbon fibers can be any known method. For example, methods commonly used industrially, such as an immersion oiling method, a roller immersion method, a roller contact method, a spray method, a papermaking method, or a guide oiling method using a metering pump, can be used.

[0040] The treatment agent of the first embodiment may be applied to the fibers in the form of, for example, an organic solvent solution or an aqueous liquid. The treatment agent is preferably applied to the carbon fibers in the form of an aqueous emulsion. The length of the fibers to which the treatment agent is applied is not particularly limited, and examples include short fibers generally called staples and long fibers generally called filaments. Carbon fibers may also be used that are blended by mixing two or more different types of staples. Examples of synthetic fibers to be blended include polyamide fibers such as nylon 6, nylon 66, polyamide 9T, and polyamide 10, polypropylene, and polyethylene. The ratio of synthetic fiber to carbon fiber when blended is not particularly limited, but is preferably 10:90 to 90:10, and more preferably 20:80 to 80:20. When blending, the treatment agent may be applied either before or after blending the carbon fiber and synthetic fiber.

[0041] Subsequently, the carbon fiber is dried to remove the solvent, such as water, contained in the solution of the treating agent, thereby obtaining carbon fibers to which the treating agent is attached. For the drying treatment here, for example, a method using hot air, a hot plate, a roller, various infrared heaters, or the like as a heat medium can be adopted.

[0042] Next, a web-forming step is carried out. In the web-forming step, the carbon fibers to which the treatment agent has been attached are carded to produce a web made of a nonwoven fabric. Carding can be carried out using a known carding machine. Examples include a flat card, a combination card, and a roller card.

[0043] The effects of the treatment agent and nonwoven fabric of this embodiment will be described. (1) The treatment agent of this embodiment is formulated by blending an epoxy compound (A). Therefore, it is possible to reduce breakage of carbon fibers to which the treatment agent has been applied when passing through a carding machine. Furthermore, it is possible to improve the strength of nonwoven fabrics obtained from carbon fibers to which the treatment agent has been applied.

[0044] (2) When the treatment agent contains a predetermined amount of a nonionic surfactant (B) or an ester compound (C), the strength of the nonwoven fabric obtained from the carbon fibers to which the treatment agent is applied can be further improved. The above embodiment may be modified as follows: The above embodiment and the following modifications may be combined with each other within the scope of technical compatibility.

[0045] The treatment agent of the above embodiment may further contain components that are typically used in treatment agents, such as stabilizers to maintain the quality of the treatment agent, antistatic agents, binders, antioxidants, and ultraviolet absorbers, within the scope that does not impair the effects of the present invention. [Example]

[0046] Examples will be given below to more specifically illustrate the configuration and effects of the present invention, but the present invention is not limited to these examples. In the following examples and comparative examples, parts means parts by mass, and % means % by mass.

[0047] Test Category 1 (Preparation of Treatment Agent) As shown in Table 1, the treatment agent for each example was prepared by gradually adding water or an organic solvent to an epoxy compound (A), a nonionic surfactant (B), an ester compound (C), and other components (D) while stirring so that the solids concentration was 30%.

[0048] [Table 1]

[0049] [Table 2]

[0050] [Table 3]

[0051] Test Category 2 (Manufacturing of Carbon Fiber Nonwoven Fabric) Using the treatment agent prepared in Test Section 1, a carbon fiber nonwoven fabric was produced. The prepared aqueous or organic solvent solution of each treatment agent was further diluted with water to obtain a 1 to 4% aqueous solution of each treatment agent. This aqueous solution was applied to short carbon fibers with a fiber length of 45 mm by spray oiling. The fibers were then dried in a hot air dryer at 105°C for 60 minutes to obtain treated short carbon fibers with the treatment agent applied. The obtained treated short carbon fibers were conditioned overnight in an atmosphere of 25°C and 65% RH before being subjected to evaluation. In Example 47 and other examples, the synthetic fibers listed in the table were blended in the specified ratios.

[0052] 10 kg of the treated short carbon fibers obtained above was subjected to a carding process with a two-loop condenser. The carding process was carried out under the conditions of 25°C x 65% RH, a spinning speed of 18.0 m / min, a spinning radius of 1 g / m, and a number of crumplings of 30 times / inch. A carbon fiber nonwoven fabric was obtained as a web.

[0053] Test category 3 (carbon fiber breakage prevention) The degree of folding of the carbon fibers was evaluated by measuring the percentage of length change of the carbon fibers before and after carding. After passing 50 mm short fibers through the card, the lengths of the short fibers were measured for n=50 fibers and the average value was calculated. The value was calculated by multiplying (average length after carding / average length before carding) by 100 and evaluated according to the following criteria.

[0054] Evaluation criteria for carbon fiber breakage prevention ◎(Good): 90% or more ○ (Acceptable): 70% or more, less than 90% × (unacceptable): Less than 70% Test Category 4 (Strength of the manufactured web) The strength of the produced web was evaluated by grasping and pulling the obtained web and measuring the ratio at which it broke. The produced web was stretched for 1 minute using a tensile strength and elongation tester at a grip length of 10 cm and a pulling speed of 10 cm / min, and it was confirmed whether the web broke during that time. Evaluation was based on the following criteria.

[0055] ·Evaluation criteria for the strength of the manufactured web ◎◎ (Excellent): The web does not break during stretching ◎ (Good): The web breaks during stretching between 50 and 60 seconds. ○ (Acceptable): The web breaks during stretching between 40 and 50 seconds. × (Not acceptable): The web breaks in less than 40 seconds during stretching. As is clear from the evaluation results of each Example and each Comparative Example in the above table, the treatment agent of the present invention can reduce breakage of carbon fibers to which the treatment agent is applied when they pass through a card, and can also improve the strength of webs obtained from carbon fibers to which the treatment agent is applied.

Claims

1. A treatment agent for producing a carbon fiber-containing nonwoven fabric, comprising an epoxy compound (A) and the following ester compound (C), The epoxy compound (A) has, as a main skeleton, at least one selected from bisphenol A, bisphenol F, and diaminediphenylmethane, A treatment agent for producing a carbon fiber-containing nonwoven fabric, characterized in that the content of the ester compound (C) in the nonvolatile matter of the treatment agent is 3 to 60 mass %. Ester compound (C): An ester compound consisting of a monohydric aliphatic alcohol and a monocarboxylic acid.

2. 2. The treatment agent for producing a carbon fiber-containing nonwoven fabric according to claim 1, wherein the epoxy compound (A) has at least one skeleton selected from a bisphenol A skeleton and a bisphenol F skeleton.

3. 2. The treatment agent for producing a carbon fiber-containing nonwoven fabric according to claim 1, wherein the content of the epoxy compound (A) in the nonvolatile content of the treatment agent is 5 to 90 mass %.

4. Further, it contains a nonionic surfactant (B), 2. The treatment agent for producing a carbon fiber-containing nonwoven fabric according to claim 1, wherein the content of the nonionic surfactant (B) in the nonvolatile content of the treatment agent is 5 to 60 mass %.

5. Further, it contains a nonionic surfactant (B), 2. The treatment agent for producing a carbon fiber-containing nonwoven fabric according to claim 1, wherein the treatment agent contains the epoxy compound (A) in an amount of 5 to 90 mass%, the nonionic surfactant (B) in an amount of 5 to 60 mass%, and the ester compound (C) in an amount of 5 to 50 mass%, where the total content of the epoxy compound (A), the nonionic surfactant (B), and the ester compound (C) is 100 mass%.

6. A carbon fiber-containing nonwoven fabric having the treating agent according to any one of claims 1 to 5 adhered thereto.

7. A method for producing a carbon fiber-containing nonwoven fabric, comprising a step of adhering the treating agent according to any one of claims 1 to 5 to short carbon fibers.

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