Treatment agent for carbon fiber precursor and carbon fiber precursor

Abstract

To provide a treatment agent for a carbon fiber precursor and a carbon fiber precursor which can reduce fuzzing of flame resistant fibers.SOLUTION: A treatment agent for a carbon fiber precursor contains a smoothing agent (A) and a non-ionic surface active agent (B), wherein the non-ionic surface active agent (B) contains a (poly)oxyalkylene derivative (B1) of the following aromatic alcohol. The (poly)oxyalkylene derivative (B1) of the aromatic alcohol represents a compound obtained by adding a total of 1 mol or more and 100 mol or less of at least one alkylene oxide selected from an ethylene oxide and a propylene oxide to 1 mol of alcohol represented by the following general formula (1). In the general formula (1), R1 represents a hydrocarbon group having one or more double bonds and 10 or more and 20 or less carbon atoms.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a treating agent for carbon fiber precursors capable of reducing the fluff of flame-resistant fibers, and to a carbon fiber precursor obtained thereby. [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 or flame-retardant materials combined with matrix resins. For example, carbon fibers are produced through a process of spinning, for example, acrylic fibers as a carbon fiber precursor, a process of drawing the fibers, a flame-retardant process, and a carbonization process. A carbon fiber precursor treatment agent may be used to impart bundling properties to the carbon fiber precursor in the spinning process of the carbon fiber precursor.

[0003] Conventionally, a treatment agent for carbon fiber precursors is known, as disclosed in Patent Document 1. Patent Document 1 discloses an acrylic fiber treatment agent for carbon fiber production, which contains a modified silicone having a modifying group containing a nitrogen atom, a surfactant, and water, and has a predetermined dimethylacetamide solubility. Patent Document 2 discloses an acrylic fiber oil agent for carbon fiber production, which contains an amino-modified silicone having a predetermined viscosity in an amount of 50% by weight or more in the pure oil content, and contains a polyoxyethylene / polyoxypropylene copolymer and / or a derivative thereof in an amount of 5 to 20% by weight in the pure oil content. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-052176 A [Patent Document 2] JP 2006-336181 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional carbon fiber precursor treating agents have a problem in that the effect of reducing fluff in the flame-retardant fiber after the carbon fiber precursor to which the carbon fiber precursor treating agent has been applied is flame-retardant is insufficient. [Means for solving the problem]

[0006] As a result of research aimed at solving the above problems, the inventors have found that a treatment agent for carbon fiber precursors containing a (poly)oxyalkylene derivative of a specified aromatic alcohol as a nonionic surfactant is precisely suitable.

[0007] Various aspects for solving the above problems will be described below. The treatment agent for carbon fiber precursors of aspect 1 is a treatment agent for carbon fiber precursors containing a smoothing agent (A) and a nonionic surfactant (B), characterized in that the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B1) of an aromatic alcohol:

[0008] (Poly)oxyalkylene derivative of aromatic alcohol (B1): A compound in which a total of 1 mole or more and 100 moles or less of at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of an alcohol represented by the following general formula (1):

[0009] [ka] (In Chemical Formula 1, R 1 : A hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds. A second aspect is the treating agent for carbon fiber precursors according to the first aspect, in which the smoothing agent (A) contains a silicone compound (A1).

[0010] Aspect 3 is the treating agent for carbon fiber precursor according to Aspect 1 or 2, in which the content of the (poly)oxyalkylene derivative (B1) in the non-volatile matter of the treating agent for carbon fiber precursor is 1 mass % or more and 50 mass % or less.

[0011] A fourth aspect is the treating agent for a carbon fiber precursor according to any one of the first to third aspects, wherein the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B2) of an aliphatic alcohol:

[0012] (Poly)oxyalkylene derivative of aliphatic alcohol (B2): A compound in which at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of a monohydric aliphatic alcohol having 10 to 20 carbon atoms and a branched structure.

[0013] A carbon fiber precursor according to a fifth aspect is characterized in that the treating agent for carbon fiber precursors according to any one of the first to fourth aspects is adhered to the carbon fiber precursor. Effect of the Invention

[0014] According to the present invention, it is possible to reduce fluff in the flame-resistant fiber after a carbon fiber precursor to which a treating agent for carbon fiber precursor has been applied is subjected to a flame-resistant treatment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] First Embodiment Hereinafter, a first embodiment of the treating agent for carbon fiber precursors (hereinafter, also simply referred to as a treating agent) of the present invention will be described. The treating agent of this embodiment contains a smoothing agent (A) and a nonionic surfactant (B) described later.

[0016] (Smoothing agent (A)) The smoothing agent (A) used in this embodiment is not particularly limited, and a known smoothing agent used in a treatment agent can be used. Examples of known smoothing agents include silicone compounds (A1), mineral oils, polyolefins, ester compounds, etc. Among these, the smoothing agent (A) is preferably one that contains a silicone compound (A1) from the viewpoint of improving the bundling property of the carbon fiber precursor to which the treatment agent is applied.

[0017] (Silicone compound (A1)) Examples of the silicone compound (A1) include dimethyl silicone, phenyl-modified silicone, amino-modified silicone, amide-modified silicone, polyether-modified silicone, aminopolyether-modified silicone, alkyl-modified silicone, alkylaralkyl-modified silicone, alkylpolyether-modified silicone, ester-modified silicone, epoxy-modified silicone, carbinol-modified silicone, mercapto-modified silicone, etc. Among these, it is preferable to use at least one selected from amino-modified silicone and polyether-modified silicone.

[0018] When the silicone compound (A1) contains at least one selected from dimethyl silicone, amino-modified silicone, and polyether-modified silicone, the effects of the present invention can be further improved.

[0019] The lower limit of the kinetic viscosity of the silicone compound (A1) at 25° C. is not particularly limited, but is preferably 50 mm 2 The upper limit of the kinetic viscosity of the silicone compound (A1) at 25° C. is not particularly limited, but is preferably 10,000 mm 2 / s or less. By specifying the 25°C kinematic viscosity of the silicone compound (A1) within this range, the effects of the present invention can be further improved. When multiple types of amino-modified silicones are used, the kinematic viscosity is the actual measured value of a mixture of the multiple amino-modified silicones used. The kinematic viscosity of the silicone compound (A1) can be measured by a known method using a Cannon-Fenske viscometer under conditions of 25°C.

[0020] When an amino-modified silicone is used as the silicone compound (A1), the lower limit of the amino equivalent is not particularly limited, but is preferably 1000 g / mol or more. The upper limit of the amino equivalent of the amino-modified silicone is not particularly limited, but is preferably 10000 g / mol or less. By defining the amino equivalent of the amino-modified silicone within this range, the effects of the present invention can be further improved.

[0021] Specific examples of the silicone compound (A1) include silicone compounds having a kinetic viscosity of 80 mm at 25° C. 2 / s, amino-modified silicone with an amino equivalent of 4000 g / mol, kinematic viscosity at 25°C of 650 mm 2 / s, amino-modified silicone with an amino equivalent of 2000 g / mol, kinematic viscosity at 25°C of 3000 mm 2 / s, amino-modified silicone with amino equivalent of 7000g / mol, kinematic viscosity at 25°C of 1500mm 2 / s, amino-modified silicone with an amino equivalent of 3800 g / mol, and a kinematic viscosity of 5000 mm at 25°C 2 / s, amino-modified silicone with an amino equivalent of 6000 g / mol, kinematic viscosity at 25°C of 500 mm 2 / s, silicone chain / polyether = 50 / 50 (mass ratio), polyether portion is ethylene oxide (hereinafter referred to as EO) / propylene oxide (hereinafter referred to as PO) = 50 / 50 (molar ratio), kinetic viscosity at 25 ° C is 100 mm 2 Examples include dimethyl silicone of / s.

[0022] (Other smoothing agents) Examples of mineral oils include aromatic hydrocarbons, paraffinic hydrocarbons, naphthenic hydrocarbons, etc. More specifically, examples of the mineral oils include spindle oil, liquid paraffin, etc. Commercially available products of these mineral oils can be appropriately used.

[0023] The polyolefin is a poly-α-olefin used as a smoothing component. Specific examples of the polyolefin include poly-α-olefins obtained by polymerizing 1-butene, 1-hexene, 1-decene, etc. Commercially available poly-α-olefins can be used as appropriate.

[0024] The ester oil is not particularly limited, and may be an ester oil produced from a fatty acid and an alcohol, such as an ester oil produced from a fatty acid having an odd or even number of hydrocarbon groups and an alcohol, as described below.

[0025] The fatty acid as the raw material of the ester oil is not particularly limited in terms of the number of carbon atoms, the presence or absence of branching, the valence, etc., and may be, for example, a higher fatty acid, a fatty acid having a cyclo ring, or a fatty acid having an aromatic ring. The alcohol as the raw material of the ester oil is not particularly limited in terms of the number of carbon atoms, the presence or absence of branching, the valence, etc., and may be, for example, a higher alcohol, an alcohol having a cyclo ring, or an alcohol having an aromatic ring.

[0026] Specific examples of ester oils include (1) ester compounds of aliphatic monoalcohols and aliphatic monocarboxylic acids, such as octyl palmitate, oleyl laurate, oleyl oleate, isotridecyl stearate, and isotetracosyl oleate; (2) complete ester compounds of aliphatic polyhydric alcohols and aliphatic monocarboxylic acids, such as 1,6-hexanediol didecanate, glycerin trioleate, trimethylolpropane trilaurate, and pentaerythritol tetraoctate; (3) complete ester compounds of aliphatic monoalcohols and aliphatic polycarboxylic acids, such as dioleyl azelate, dioleyl thiodipropionate, diisocetyl thiodipropionate, diisostearyl thiodipropionate, and an ester obtained by reacting 1 mole of thiodipropionic acid with 2 moles of 2-hexyl-1-decanol; and (4) benzyl oleate, benzyl laurate, and alkylene oxy group compounds of cardanol. (5) complete ester compounds of aromatic polyhydric alcohols or their alkylene oxide adducts with aliphatic monocarboxylic acids, such as esters of a compound having an alkylene oxide added to 3-[(8Z,11Z)-8,11,14-pentadecatrienyl]phenol and lauric acid; (6) complete ester compounds of aliphatic monohydric alcohols and aromatic polyhydric carboxylic acids, such as bisphenol A dilaurate and an ester obtained by reacting 1 mole of an ethylene oxide adduct of bisphenol A with 2 moles of lauric acid; (7) natural oils and fats, such as coconut oil, rapeseed oil, sunflower oil, soybean oil, castor oil, sesame oil, fish oil, and beef tallow. The aromatic monoalcohol may be not only a chemically synthesized one, but also a naturally derived mixture such as cardanol obtained from cashew nut shell liquid.

[0027] These lubricants may be used alone or in combination of two or more. The lower limit of the content of the smoothing agent (A) in the non-volatile content of the treatment agent is set appropriately, but is preferably 5 mass% or more, more preferably 10 mass% or more. When the content is 5 mass% or more, the smoothness of the carbon fiber precursor to which the treatment agent is applied can be further improved. The upper limit of the content of the smoothing agent (A) is set appropriately, but is preferably 90 mass% or less, more preferably 85 mass% or less. When the content is 90 mass% or less, the stability of the treatment agent can be improved. Note that ranges that combine the above upper and lower limits in any way are also envisioned.

[0028] The non-volatile content of the treatment agent refers to the residue remaining after the measurement sample is heat-treated at 105°C for 2 hours (the same applies below). The lower limit of the content of the silicone compound (A1) in the non-volatile content of the treatment agent is set appropriately, but is preferably 5 mass% or more, more preferably 10 mass% or more. When the content is 5 mass% or more, the bundling property of the carbon fiber precursor to which the treatment agent is applied can be improved. The upper limit of the content of the silicone compound (A1) is set appropriately, but is preferably 90 mass% or less, more preferably 85 mass% or less. When the content is 90 mass% or less, the stability of the treatment agent can be improved. Note that ranges in which the above upper and lower limits are arbitrarily combined are also envisioned.

[0029] (Nonionic Surfactant (B)) The nonionic surfactant (B) used in this embodiment contains the following aromatic alcohol (poly)oxyalkylene derivative (B1). The aromatic alcohol (poly)oxyalkylene derivative (B1) can reduce fluff in the flame-resistant fiber after the carbon fiber precursor to which the treatment agent has been applied is flame-resistant. In addition, it can improve the bundling property of the carbon fiber precursor to which the treatment agent has been applied.

[0030] (Polyoxyalkylene derivatives of aromatic alcohols (B1)) The (poly)oxyalkylene derivative (B1) of an aromatic alcohol is a compound in which a total of 1 to 100 moles of at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of an alcohol represented by the following general formula (1):

[0031] [ka] (In Chemical Formula 2, R 1 : A hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds. R 1 The hydrocarbon group having one or more double bonds may be an alkenyl group having one double bond, or an alkadienyl group or an alkatrienyl group having two or more double bonds. The hydrocarbon group may have a linear or branched chain structure. The number of carbon atoms in the hydrocarbon group is 10 to 20, preferably 12 to 18, more preferably 14 to 16. Any combination of the upper and lower limits above is also contemplated.

[0032] Specific examples of unsaturated hydrocarbon groups having one double bond in the hydrocarbon group include a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, and an icocenyl group.

[0033] Specific examples of unsaturated hydrocarbon groups having two double bonds in the hydrocarbon group include decadienyl, undecadienyl, dodecadienyl, tridecadienyl, tetradecadienyl, pentadecadienyl, hexadecadienyl, heptadecadienyl, octadecadienyl, and icosadienyl groups.

[0034] Specific examples of unsaturated hydrocarbon groups having three double bonds in the hydrocarbon group include, for example, a decatrienyl group, an undecatrienyl group, a dodecatrienyl group, a tridecatrienyl group, a tetradecatrienyl group, a pentadecatrienyl group, a hexadecatrienyl group, a heptadecatrienyl group, an octadecatrienyl group, and an icosatrienyl group.

[0035] The ethylene oxide and propylene oxide added to the aromatic alcohol may be ethylene oxide alone, propylene oxide alone, or both ethylene oxide and propylene oxide. When two types of alkylene oxide are used, the addition form may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited. In addition to ethylene oxide or propylene oxide, butylene oxide, etc. may be added as the alkylene oxide.

[0036] The number of moles of alkylene oxide added is 1 mole or more and 100 moles or less, preferably 2 moles or more and 60 moles or less. Any combination of the upper and lower limits above is also possible. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of aromatic alcohol in the raw material.

[0037] Specific examples of the (poly)oxyalkylene derivative (B1) of aromatic alcohol include compounds obtained by adding alkylene oxide to cardanol, 3-[(8Z,11Z)-8,11,14-pentadecatrienyl]phenol, etc. The aromatic monoalcohol used as the raw material may be chemically synthesized or may be a mixture of natural origin such as cardanol obtained from cashew nut shell liquid.

[0038] These (poly)oxyalkylene derivatives (B1) of aromatic alcohols may be used alone or in appropriate combination of two or more. (Poly)oxyalkylene derivatives of aliphatic alcohols (B2) The nonionic surfactant (B) used in this embodiment preferably contains the following aliphatic alcohol (poly)oxyalkylene derivative (B2). The aliphatic alcohol (poly)oxyalkylene derivative (B2) is a compound in which at least one alkylene oxide selected from ethylene oxide and propylene oxide is added to 1 mole of a monohydric aliphatic alcohol having 10 to 20 carbon atoms and a branched structure. When the treating agent contains the aliphatic alcohol (poly)oxyalkylene derivative (B2), the bundling property of the carbon fiber precursor to which the treating agent is applied can be further improved.

[0039] The branching position of the monohydric aliphatic alcohol having a branched structure is not particularly limited, and may be, for example, a carbon chain branched at the α-position or a carbon chain branched at the β-position. Also, it may be a primary alcohol or a secondary alcohol. Also, it may be a saturated aliphatic alcohol or an unsaturated aliphatic alcohol.

[0040] Specific examples of monohydric aliphatic alcohols having 10 to 20 carbon atoms and a branched structure include (1) branched alkyl alcohols such as isodecanol (isodecyl alcohol), isododecanol (isododecyl alcohol), isotridecanol (isotridecyl alcohol), isotetradecanol (isotetradecyl alcohol), isopentadecanol (isopentadecyl alcohol), isohexadecanol (isohexadecyl alcohol), isoheptadecanol (isoheptadecyl alcohol), isooctadecanol (isooctadecyl alcohol), isononadecanol (isononadecyl alcohol), and isoeicosanol (isoeicosyl alcohol); (2) isohexadecanol (3) Guerbet alcohols such as 2-ethyl-1-octanol, 2-ethyl-decanol, 2-butyl-1-hexanol, 2-butyl-1-octanol, 2-butyl-1-decanol, 2-hexyl-1-octanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-octyl-1-dodecanol, 2-hexyl-1-octanol, 2-hexyl-1-dodecanol, 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyl-1-octanol, 2-(4-methylhexyl)-8-methyl-1-decanol, and 2-(1,5-dimethylhexyl)-5,9-dimethyl-1-decanol.

[0041] Examples of alkylene oxides used as raw materials for forming the (poly)oxyalkylene structure of the (poly)oxyalkylene derivative (B2) of an aliphatic alcohol include ethylene oxide and propylene oxide. The number of moles of alkylene oxide added is appropriately set, but is preferably 1 mole or more and 60 moles or less, more preferably 2 moles or more and 50 moles or less, and even more preferably 3 moles or more and 40 moles or less. Any combination of the above upper and lower limits is also possible. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of monohydric aliphatic alcohol in the charged raw material. The alkylene oxide may be one type of alkylene oxide used alone, or two types of alkylene oxides may be used in appropriate combination. When two types of alkylene oxides are used, the addition form may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited.

[0042] Specific examples of the (poly)oxyalkylene derivative (B2) of an aliphatic alcohol include a compound in which an alkylene oxide is added to isodecyl alcohol, a compound in which an alkylene oxide is added to isotridecyl alcohol, a compound in which an alkylene oxide is added to a mixed alcohol of isotetradecyl alcohol and isopentadecyl alcohol, and a compound in which an alkylene oxide is added to 2-hexyl-1-dodecanol.

[0043] These (poly)oxyalkylene derivatives (B2) of aliphatic alcohols may be used alone or in appropriate combination of two or more. (Other nonionic surfactants (B3)) Furthermore, a nonionic surfactant (B3) other than the above-mentioned (poly)oxyalkylene derivative of aromatic alcohol (B1) and the (poly)oxyalkylene derivative of aliphatic alcohol (B2) may be blended.

[0044] Other examples of the nonionic surfactant (B3) 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 alcohols, amine compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to a primary organic amine, partial ester compounds of carboxylic acids and polyhydric alcohols, amide compounds in which amine compounds and carboxylic acids are condensed, compounds having a (poly)oxyalkylene structure in which alkylene oxide is added to fatty acid amides, and compounds having a polyoxyalkylene structure such as block copolymers having a polyoxyethylene chain and a polyoxypropylene chain.

[0045] Specific examples of alcohols that can be used as raw materials for the other nonionic surfactants (B3) 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, and isotriacontanol; Examples of the branched alkyl alcohols include isohexadecanol, isoheptadecanol, isooctadecanol, isonadecanol, isoeicosanol, isoheneicosanol, isodocosanol, isotricosanol, isotetracosanol, isopentacosanol, isohexacosanol, isoheptacosanol, isooctacosanol, isononacosanol, and isopentadecanol; (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.

[0046] Specific examples of carboxylic acids used as raw materials for the other nonionic surfactants (B3) include, for example, (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.

[0047] The alkylene oxide used as a raw material for forming the (poly)oxyalkylene structure of the other nonionic surfactant (B3) is preferably an alkylene oxide having 2 to 4 carbon atoms. Specific examples of alkylene oxide include, for example, ethylene oxide, propylene oxide, butylene oxide, etc. The number of moles of alkylene oxide added is appropriately set, but is preferably 0.1 to 250 moles, more preferably 1 to 200 moles, and even more preferably 2 to 150 moles. A range in which the above upper and lower limits are arbitrarily combined is also assumed. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of the compound to be added in the charged raw material. The alkylene oxide may be one type of alkylene oxide 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, and a combination of block addition and random addition, and is not particularly limited.

[0048] Specific examples of polyhydric alcohols used as raw materials for the other nonionic surfactants (B3) 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, 2-methyl-2-hydroxymethyl-1,3-propanediol, trimethylolpropane, sorbitan, pentaerythritol, and sorbitol.

[0049] Specific examples of the aliphatic amines used as raw materials for the other nonionic surfactants (B3) include methylamine, ethylamine, butylamine, octylamine, laurylamine, octadecylamine, octadecenylamine, and coconut amine.

[0050] Specific examples of fatty acid amides used as raw materials for the other nonionic surfactants (B3) include octyl acid amide, lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, behenic acid amide, and lignoceric acid amide.

[0051] The block copolymer of polyoxyethylene chain and polyoxypropylene chain is not particularly limited as long as it has a polyoxypropylene chain with low hydrophilicity and a polyoxyethylene chain with high hydrophilicity and has a surfactant effect. The number of polyoxyethylene chains and polyoxypropylene chains in the molecule is not particularly limited, and may be, for example, a block copolymer consisting of one polyoxypropylene chain and one polyoxyethylene chain, or a poloxamer surfactant consisting of a polyoxypropylene chain and two polyoxyethylene chains sandwiching it. The number of moles of ethylene oxide added to form the polyoxyethylene chain is not particularly limited, and may be, for example, 5 moles or more and 200 moles or less. The number of moles of propylene oxide added to form the polyoxypropylene chain is not particularly limited, and may be, for example, 5 moles or more and 100 moles or less.

[0052] Specific examples of other nonionic surfactants (B3) include, for example, a compound in which an alkylene oxide is added to tetradecyl alcohol, a compound in which an alkylene oxide is added to dodecyl alcohol, a polyoxyalkylene block copolymer having a number average molecular weight of 5,000 (EO / PO=30 / 70 (molar ratio)) obtained by addition polymerization of EO and PO in block form to ethylene glycol, a polyoxyalkylene block copolymer having a number average molecular weight of 10,000 (EO / PO=70 / 30 (molar ratio)) obtained by addition polymerization of EO and PO in block form to ethylene glycol, a compound in which an alkylene oxide is added to hydrogenated castor oil, and a compound in which an alkylene oxide is added to nonylphenol.

[0053] These other nonionic surfactants (B3) may be used alone or in appropriate combination of two or more kinds. The lower limit of the content of the nonionic surfactant (B) in the nonvolatile content of the treatment agent is appropriately set, but is preferably 10% by mass or more, more preferably 15% by mass or more. When the content is 10% by mass or more, the stability of the treatment agent can be improved. The upper limit of the content of the nonionic surfactant (B) is appropriately set, but is preferably 95% by mass or less, more preferably 94% by mass or less. When the content is 95% by mass or less, the smoothness can be improved by increasing the amount of the smoothing agent (A). Note that ranges that combine the above upper and lower limits in any way are also envisioned.

[0054] The lower limit of the content of the aromatic alcohol (poly)oxyalkylene derivative (B1) in the non-volatile content of the treatment agent is appropriately set, but is preferably 0.5 mass% or more, more preferably 1 mass% or more. When the content is 0.5 mass% or more, the fluff of the flame-resistant fiber after the carbon fiber precursor to which the treatment agent is applied is flame-resistant can be reduced. The upper limit of the content of the aromatic alcohol (poly)oxyalkylene derivative (B1) is appropriately set, but is preferably 65 mass% or less, more preferably 50 mass% or less. When the content is 65 mass% or less, the fluff of the flame-resistant fiber after the carbon fiber precursor to which the treatment agent is applied is flame-resistant can be reduced. Note that a range in which the above upper and lower limits are arbitrarily combined is also envisaged.

[0055] The lower limit of the content ratio (B1 / B) of the aromatic alcohol (poly)oxyalkylene derivative (B1) in the total nonionic surfactant (B) blended in the treatment agent is appropriately set, but is preferably 2 mass% or more, more preferably 5 mass% or more. When such a content ratio is 2 mass% or more, the fluff of the flame-resistant fiber after the carbon fiber precursor to which the treatment agent is applied is flame-resistant can be reduced. The upper limit of the content ratio (B1 / B) of the aromatic alcohol (poly)oxyalkylene derivative (B1) in the total nonionic surfactant (B) blended in the treatment agent is appropriately set, but is preferably 95 mass% or less, more preferably 90 mass% or less. When such a content ratio is 95 mass% or less, the fluff of the flame-resistant fiber after the carbon fiber precursor to which the treatment agent is applied is flame-resistant can be reduced. Note that a range in which the above upper and lower limits are arbitrarily combined is also assumed.

[0056] The lower limit of the content of the (poly)oxyalkylene derivative (B2) of an aliphatic alcohol in the non-volatile content of the treatment agent is appropriately set, but is preferably 1 mass% or more, more preferably 2 mass% or more. When the content is 1 mass% or more, the bundling property of the carbon fiber precursor to which the treatment agent is applied can be improved. The upper limit of the content of the (poly)oxyalkylene derivative (B2) of an aliphatic alcohol is appropriately set, but is preferably 60 mass% or less, more preferably 50 mass% or less. When the content is 60 mass% or less, the bundling property of the carbon fiber precursor to which the treatment agent is applied can be efficiently improved. Note that a range in which the above upper and lower limits are arbitrarily combined is also envisaged.

[0057] According to the treatment agent of the first embodiment, the following effects can be obtained. (1-1) The treatment agent of the first embodiment is configured to contain a smoothing agent (A) and a nonionic surfactant (B) containing the above-mentioned aromatic alcohol (poly)oxyalkylene derivative (B1). Therefore, it is possible to reduce the fluff of the flame-resistant fiber after the carbon fiber precursor to which the treatment agent has been applied is flame-resistant. In addition, it is possible to improve the bundling property of the carbon fiber precursor to which the treatment agent has been applied. Therefore, it is possible to improve the manufacturing characteristics of the flame-resistant fiber.

[0058] (1-2) When the treating agent contains the above-mentioned (poly)oxyalkylene derivative (B2) of an aliphatic alcohol, the bundling property of the carbon fiber precursor to which the treating agent is applied can be further improved, and therefore the production characteristics of the flame-resistant fiber can be further improved.

[0059] <Second embodiment> Next, a second embodiment of the carbon fiber precursor according to the present invention will be described. The carbon fiber precursor of this embodiment has the treatment agent of the first embodiment adhered thereto.

[0060] The carbon fiber precursor is preferably a synthetic fiber that becomes a carbon fiber by undergoing a carbonization process described later. The fiber raw material constituting the carbon fiber precursor is not particularly limited, but examples thereof include (1) polyester-based fibers such as polyethylene terephthalate, polypropylene terephthalate, and polylactic acid ester, (2) polyamide-based fibers such as nylon 6 and nylon 66, (3) polyacrylic-based fibers such as polyacrylic and modacrylic, (4) polyolefin-based fibers such as polyethylene and polypropylene, (5) cellulose-based fibers, (6) lignin-based fibers, (7) phenolic resins, and (8) pitch. Furthermore, the polyacrylic fiber is preferably composed of a fiber mainly composed of polyacrylonitrile obtained by copolymerizing at least 90 mol% or more of acrylonitrile and 10 mol% or less of a flame retardant-promoting component. As the flame retardant-promoting component, for example, a vinyl group-containing compound having copolymerizability with acrylonitrile can be suitably used.

[0061] There is no particular restriction on the ratio of the treatment agent of the first embodiment that is applied to the carbon fiber precursor, but it is preferable to apply the treatment agent (not including the solvent) to the carbon fiber precursor in an amount of 0.1 mass % or more and 2 mass % or less, and it is more preferable to apply the treatment agent to the carbon fiber precursor in an amount of 0.3 mass % or more and 1.2 mass % or less.

[0062] As a method for adhering the treatment agent to the carbon fiber precursor, for example, a method can be applied in which the treatment agent is adhered in the form of a treatment agent-containing composition containing the treatment agent of the first embodiment and a solvent, or in the form of a diluted solution further diluted with a solvent, by a known method, for example, a dipping method, a spraying method, a roller method, or a guide oiling method using a metering pump.

[0063] Next, a method for producing carbon fibers using the carbon fiber precursor of this embodiment will be described. The method for producing carbon fibers preferably includes the following steps 1 to 3. Step 1: A spinning step in which a raw material that will become a carbon fiber precursor is spun and the treatment agent of the first embodiment is applied to the raw material.

[0064] Step 2: A flame retardant treatment step of converting the carbon fiber precursor obtained in step 1 into a flame retardant fiber in an oxidizing atmosphere of preferably 200°C or higher and 300°C or lower, more preferably 230°C or higher and 270°C or lower.

[0065] Step 3: A carbonization treatment step of carbonizing the flame-retardant fiber obtained in step 2 in an inert atmosphere at a temperature of preferably 300° C. or higher and 2000° C. or lower, more preferably 300° C. or higher and 1300° C. or lower.

[0066] The above steps 2 and 3 constitute a firing step. The treatment agent may be applied to the raw fiber of the carbon fiber precursor at any stage of the spinning process, but it is preferable to apply the treatment agent once before the drawing process. Furthermore, the treatment agent may be applied again at any stage after the drawing process. For example, the treatment agent may be applied again immediately after the drawing process, at the winding stage, or immediately before the flame retardant treatment process.

[0067] The oxidizing atmosphere in the flame-proofing treatment step is not particularly limited, and for example, an air atmosphere can be used. The inert atmosphere in the carbonization treatment step is not particularly limited, and for example, a nitrogen atmosphere, an argon atmosphere, a vacuum atmosphere, or the like can be adopted.

[0068] According to the carbon fiber precursor of the second embodiment, the following effects can be obtained. (2-1) In the carbon fiber precursor of the second embodiment, the treatment agent of the first embodiment is attached. Therefore, it is possible to reduce the fluff of the flame-resistant fiber after the carbon fiber precursor is flame-resistant treated. This can improve the yarn quality. In addition, it is possible to improve the bundling property of the carbon fiber precursor to which the treatment agent of the first embodiment is applied. This can reduce winding around the roller and improve the production efficiency.

[0069] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs. The above-mentioned treatment agent may contain commonly used ingredients such as stabilizers and antistatic agents for maintaining quality, oily ingredients other than those mentioned above, surfactants other than those mentioned above, antistatic agents, binders, antioxidants, UV absorbers, defoamers, etc., within the range that does not impair the effects of the present invention. From the viewpoint of efficiently exerting the effects of the present invention, the amount of other ingredients other than the solvent in the treatment agent is preferably 20% by mass or less, and more preferably 10% by mass or less. EXAMPLES

[0070] In the following, examples will be given to more specifically describe 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.

[0071] Test Category 1 (Preparation of treatment agent and aqueous liquid) Example 1 The treatment agent of Example 1 has a kinetic viscosity of 80 mm at 25° C. as a smoothing agent (A). 240 parts of amino-modified silicone having an amino equivalent of 4000g / mol, 40 parts of a compound (B1-1) in which 5 moles of EO are added to 1 mole of cardanol A as a nonionic surfactant (B), 10 parts of a compound (B2-1) in which 10 moles of EO are added to 1 mole of isodecyl alcohol, and 10 parts of a compound (B3-1) in which 20 moles of EO and 20 moles of PO are randomly added to 1 mole of tetradecyl alcohol were added to a beaker and mixed well to prepare the treatment agent of Example 1. Next, while continuing to stir, ion-exchanged water was gradually added so that the solid content concentration was 25%, and an aqueous solution of 25% of the treatment agent of Example 1 was prepared.

[0072] (Examples 2 to 39, Comparative Examples 1 to 5) Each of the treatment agents of Examples 2 to 39 and Comparative Examples 1 to 5 was prepared in the same manner as in Example 1 using the components shown in Tables 1 and 2.

[0073] The type and content of the smoothing agent (A), the type and content of the nonionic surfactant (B), and the type and content of other components in the treatment agent of each example are as shown in the "Smoothing agent (A)", "Nonionic surfactant (B)", and "Other components" columns in Tables 1 and 2, respectively.

[0074] [Table 1]

[0075] [Table 2] Details of the smoothing agent (A), nonionic surfactant (B), and other components shown in Tables 1 and 2 are as follows.

[0076] <Smoothing agent (A)> (Silicone compound (A1)) A1-1: Kinematic viscosity at 25℃ is 80mm 2 / s, amino-modified silicone with amino equivalent of 4000g / mol A1-2: Kinematic viscosity at 25℃ is 650mm 2 / s, amino-modified silicone with amino equivalent of 2000g / mol A1-3: Kinematic viscosity at 25℃ is 3000mm 2 / s, amino-modified silicone with amino equivalent of 7000g / mol A1-4: Kinematic viscosity at 25℃ is 1500mm 2 / s, amino-modified silicone with amino equivalent of 3800g / mol A1-5: Kinematic viscosity at 25℃ is 5000mm 2 / s, amino-modified silicone with amino equivalent of 6000g / mol A1-6: Kinematic viscosity at 25℃ is 500mm 2 / s, a polyether-modified silicone in which the silicone chain / polyether is 50 / 50 (mass ratio) and the polyether portion is EO / PO=50 / 50 (molar ratio) A1-7: Kinematic viscosity at 25°C is 100mm 2 / s Dimethyl Silicone (Other smoothing agents (A2)) A2-1: Ester obtained by reacting 1 mole of bisphenol A EO 2 mole adduct with 2 moles of lauric acid A2-2: Ester obtained by reacting 1 mole of thiodipropionic acid with 2 moles of 2-hexyl-1-decanol A2-3: Octyl palmitate A2-4: Ester of lauric acid and a compound obtained by adding 30 parts of EO to 100 parts of cashew nut shell liquid (the number of moles of EO added per mole of alcohol represented by the above general formula (1) is about 10 moles) *Cashew nut shell liquid used was CNSL (a mixture of 82% cardanol and 18% cardol by mass in monomers) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the cardanol side chains are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds.

[0077] <Nonionic surfactant (B)> (Polyoxyalkylene derivatives of aromatic alcohols (B1)) B1-1: A compound in which 5 moles of EO are added to 1 mole of cardanol A. B1-2: A compound in which 15 moles of EO are added to 1 mole of cardanol B. B1-3: A compound in which 30 moles of EO are added to 1 mole of Cardanol A. B1-4: A compound in which 45 moles of EO are added to 1 mole of cardanol B. B1-5: A compound obtained by adding 15 moles of PO to 1 mole of cardanol A, and then adding 25 moles of EO to the resulting mixture. B1-6: A compound in which 1 mole of cardanol A is randomly added with 10 moles of EO and 15 moles of PO, and then 1 mole of PO is added. B1-7: A compound in which 20 moles of EO and 20 moles of PO are randomly added to 1 mole of cardanol B. B1-8: A compound in which 300 parts of EO are added to 100 parts of cashew nut shell liquid (the number of moles of EO added per mole of alcohol represented by the above general formula (1) is about 10 moles) *Cardanol A used was LB-7000 (a mixture of 90% cardanol and 10% cardol by mass) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of the (poly)oxyalkylene derivative (B1) of aromatic alcohol listed in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0078] Cardanol B was LB-7250 (a mixture of 95% by mass of cardanol and 5% by mass of cardol) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of the aromatic alcohol (poly)oxyalkylene derivative (B1) listed in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0079] The cashew nut shell liquid used was CNSL (a mixture of 82% by mass of cardanol and 18% by mass of cardol in the monomer) manufactured by Tohoku Kako Co., Ltd. The hydrocarbon groups in the side chains of cardanol are 5% by mass of pentadecyl groups with 0 unsaturated bonds, 35% by mass of pentadecenyl groups with 1 unsaturated bond, 20% by mass of pentadecadienyl groups with 2 unsaturated bonds, and 40% by mass of pentadecatrienyl groups with 3 unsaturated bonds. The content of the aromatic alcohol (poly)oxyalkylene derivative (B1) listed in Tables 1 and 2 indicates the content ratio of the compound derived from the above general formula (1).

[0080] (Poly)oxyalkylene derivatives of aliphatic alcohols (B2) B2-1: A compound in which 10 moles of EO are added to 1 mole of isodecyl alcohol B2-2: A compound in which 10 moles of EO are added to 1 mole of isotridecyl alcohol B2-3: A compound in which 20 moles of EO are added to 1 mole of a mixed alcohol of isotetradecyl alcohol and isopentadecyl alcohol. B2-4: A compound in which 20 moles of EO are added to 1 mole of 2-hexyl-1-dodecanol B2-5: A compound obtained by adding 10 moles of PO to 1 mole of isotridecyl alcohol, and then adding 10 moles of EO to the resulting mixture. B2-6: A compound in which 20 moles of EO and 20 moles of PO are randomly added to 1 mole of a mixed alcohol of isotetradecyl alcohol and isopentadecyl alcohol. B2-7: A compound obtained by adding 10 moles of PO to 1 mole of 2-hexyl-1-dodecanol and then adding 20 moles of EO. (Other nonionic surfactants (B3)) B3-1: A compound in which 20 moles of EO and 20 moles of PO are randomly added to 1 mole of tetradecyl alcohol. B3-2: A compound in which 10 moles of EO are added to 1 mole of dodecyl alcohol. B3-3: A polyoxyalkylene block copolymer with a number average molecular weight of 5000 (EO / PO=30 / 70 (molar ratio)) obtained by addition polymerization of EO and PO in blocks to ethylene glycol B3-4: A polyoxyalkylene block copolymer with a number average molecular weight of 10,000 (EO / PO=70 / 30 (molar ratio)) obtained by addition polymerization of EO and PO in blocks to ethylene glycol B3-5: Compound in which 20 moles of EO are added to 1 mole of hydrogenated castor oil B3-6: A compound in which 15 moles of EO are added to 1 mole of nonylphenol (Other ingredients) C-1: Sodium dodecylbenzenesulfonate C-2: Potassium 2-ethylhexyl phosphate C-3: Potassium acetate C-4: N,N-bis(polyoxyethylene (EO 10 moles added)) dodecaneamine acetate Test Category 2 (Manufacturing of Carbon Fiber Precursors and Carbon Fibers) Using the aqueous liquid containing the treatment agent prepared in Test Section 1, a carbon fiber precursor, a flame-retardant yarn (flame-retardant fiber), and a carbon fiber were produced.

[0081] First, in step 1, acrylic resin was wet-spun as a synthetic fiber, which is a carbon fiber precursor. Specifically, a copolymer with an intrinsic viscosity of 1.80 consisting of 95% by mass of acrylonitrile, 3.5% by mass of methyl acrylate, and 1.5% by mass of methacrylic acid was dissolved in dimethylacetamide (DMAC) to prepare a spinning dope with a polymer concentration of 21.0% by mass and a viscosity of 500 poise at 60°C. The spinning dope was discharged from a spinneret with a hole diameter (inner diameter) of 0.075 mm and 12,000 holes into a coagulation bath of a 70% by mass aqueous solution of DMAC kept at a spinning bath temperature of 35°C at a draft ratio of 0.8.

[0082] The solidified yarn was stretched 5 times in a water washing tank while removing the solvent, to produce a water-swollen acrylic fiber strand (raw fiber). The treatment agent prepared in Test Section 1 was applied to this acrylic fiber strand so that the amount of non-volatile matter of the treatment agent adhered was 1 mass% (not including the solvent). The treatment agent was applied by immersion using a 4% ion-exchange aqueous solution of the treatment agent. Thereafter, the acrylic fiber strand was subjected to a drying and densifying treatment with heated rollers at 130°C, and further stretched 1.7 times between heated rollers at 170°C, after which the carbon fiber precursor was wound onto a yarn tube using a winding device (hereinafter also referred to as a winder).

[0083] Next, in step 2, a yarn was unwound from the wound carbon fiber precursor and subjected to a flame-retardant treatment in an air atmosphere for 1 hour in a flame-retardant furnace having a temperature gradient of 230 to 270°C, and then the yarn was wound onto a yarn tube via a conveying roller to obtain a flame-retardant yarn (flame-retardant fiber).

[0084] Next, in step 3, the yarn was unwound from the wound flame-retardant yarn, and converted into carbon fiber by baking in a carbonization furnace having a temperature gradient of 300 to 1,300°C under a nitrogen atmosphere, and then wound around a yarn tube to obtain carbon fiber.

[0085] Test Category 3 (Evaluation) The bundleability of the acrylic fiber strands to which the treatment agents of the Examples and Comparative Examples were applied was evaluated. In addition, the fluff of the flame-resistant fiber obtained from the acrylic fiber strands to which the treatment agents were applied was evaluated. The test procedure is shown below.

[0086] (Fluff) In step 2, the flame-retardant fiber that had been subjected to the flame-retardant treatment was visually observed for the presence or absence of fluff on the rollers that transported the flame-retardant fiber, and was evaluated according to the following criteria. The test results are shown in the "Fluff" column in Tables 1 and 2.

[0087] ·Evaluation criteria for flame-retardant fluff ◎ (Good): Almost no fluff is visible ○ (Acceptable): A small amount of fluff is visible, but not to the extent that it causes problems in operation. × (bad): There is a lot of fluff, and it wraps around the rollers, causing problems in operation. (Focusing) In step 1, the bundling state of the acrylic fiber strand oiled with the treatment agent was visually observed as it passed through the heated roller, and the bundling ability was evaluated according to the following criteria. The test results are shown in the "Bundling ability" column in Tables 1 and 2.

[0088] ·Evaluation criteria for bundleability of acrylic fiber strands ◎ (Good): Good bundling, no wrapping around the heating roller, no problems with operability ○(Acceptable): The yarn may come apart slightly, but there is no breakage and no problem with operability. × (bad): There is a lot of loose yarn and frequent yarn breakage occurs, affecting operability. From the results in Tables 1 and 2, it is clear that the present invention can reduce the fluff of the flame-resistant fiber and improve the bundling property of the acrylic fiber strand.

Claims

1. A treatment agent for carbon fiber precursors, comprising a smoothing agent (A) and a nonionic surfactant (B), A treatment agent for carbon fiber precursors, characterized in that the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B1) of an aromatic alcohol: (Poly)oxyalkylene derivative of aromatic alcohol (B1): A compound in which at least one alkylene oxide selected from ethylene oxide and propylene oxide is added in a total amount of 1 mol to 100 mol to 1 mol of an alcohol represented by the following general formula (1): 【Chemistry 1】 (In Chemical Formula 1, R １ : a hydrocarbon group having 10 to 20 carbon atoms and one or more double bonds.

2. The treatment agent for carbon fiber precursors according to claim 1 , wherein the smoothing agent (A) contains a silicone compound (A1).

3. The treatment agent for carbon fiber precursors according to claim 1, wherein a content ratio of the (poly)oxyalkylene derivative (B1) in a non-volatile matter of the treatment agent for carbon fiber precursors is 1 mass % or more and 50 mass % or less.

4. 2. The treatment agent for carbon fiber precursors according to claim 1, wherein the nonionic surfactant (B) contains the following (poly)oxyalkylene derivative (B2) of an aliphatic alcohol: (Poly)oxyalkylene derivative of aliphatic alcohol (B2): a compound obtained by adding at least one alkylene oxide selected from ethylene oxide and propylene oxide to 1 mole of a monohydric aliphatic alcohol having 10 to 20 carbon atoms and a branched structure.

5. A carbon fiber precursor having the treating agent for carbon fiber precursors according to any one of claims 1 to 4 adhered thereto.

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