Treatment agents for carbon fiber precursors and their applications

Abstract

The purpose of the present invention is to provide an agent for treating a carbon fiber precursor, the agent being capable of suppressing degradation of the carbon fiber precursor even when the carbon fiber precursor produced by applying the agent for treating a carbon fiber precursor is stored for a long period of time, and being capable of obtaining carbon fibers having excellent physical properties even when the carbon fiber precursor stored for a long period of time is used.　This agent for treating a carbon fiber precursor contains (A) a silicone having an amino group, (B) a silicone having an aryl group, and (C1) an aliphatic (poly)oxyalkylene derivative. The weight ratio (B / A) of the silicone (B) having an aryl group to the silicone (A) having an amino group is preferably 1 or less.

Description

Technical Field

[0001] The present invention relates to a treatment agent for carbon fiber precursors and its uses. More specifically, it relates to a treatment agent used in the production of carbon fiber precursors, a carbon fiber precursor (hereinafter sometimes referred to as a precursor) using the treatment agent, and a method for producing carbon fiber using the treatment agent.

Background Art

[0002] Utilizing its excellent mechanical properties, carbon fiber is widely used in aerospace applications, sports applications, general industrial applications, etc. as a reinforcing fiber for composite materials with a plastic called matrix resin. As a method for producing carbon fiber, first, a carbon fiber precursor is produced (this production process may be referred to as a spinning process). This carbon fiber precursor is converted into a flame-resistant fiber in an oxidizing atmosphere at 200 - 300 °C (this process may hereinafter be referred to as a flame-resistant treatment process), and subsequently carbonized in an inert atmosphere at 300 - 2000 °C (this process may hereinafter be referred to as a carbonization treatment process). This method is common (hereinafter, the flame-resistant treatment process and the carbonization treatment process may together be referred to as a firing process). In such a firing process, fusion between single fibers occurs, easily causing problems such as fuzz and yarn breakage, which has been an obstacle to improving productivity.

[0003] In order to prevent fusion between single fibers in the firing process, a silicone-based treatment agent is applied during the production of carbon fiber precursors, and many techniques have been proposed to apply the treatment agent in the form of an aqueous emulsion to uniformly apply the treatment agent. (See Patent Documents 1 - 2)

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] However, when carbon fiber precursors produced with such treatment agents were stored for long periods, there was a problem of deterioration of the carbon fiber precursors over time. Therefore, when carbon fiber was produced by firing carbon fiber precursors that had been stored for a long period, problems arose such as the generation of fluff during the firing process and a decrease in the strength of the carbon fiber after firing. In view of the above-mentioned conventional technological background, the object of the present invention is to provide a carbon fiber precursor treatment agent that can suppress the deterioration of carbon fiber precursors when carbon fiber precursors manufactured by applying the treatment agent are stored for a long period of time, a carbon fiber precursor using the treatment agent, and a method for producing carbon fiber using the treatment agent. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the present inventors have found that a carbon fiber precursor treatment agent containing an amino group-containing silicone (A), an aryl group-containing silicone (B), and an aliphatic (poly)oxyalkylene derivative (C1) can suppress the deterioration of carbon fiber precursors when carbon fiber precursors produced with the treatment agent are stored for a long period of time, and have arrived at the present invention.

[0007] In other words, the carbon fiber precursor treatment agent of the present invention includes the following embodiments. <1> A treatment agent for carbon fiber precursors, containing an amino group-containing silicone (A), an aryl group-containing silicone (B), and an aliphatic (poly)oxyalkylene derivative (C1). <2> The weight ratio (B / A) of the aryl group-containing silicone (B) to the amino group-containing silicone (A) is 1 or less. <1> Treatment agent for carbon fiber precursors as described above. <3> The weight ratio (B / C1) of the aryl group-containing silicone (B) to the aliphatic (poly)oxyalkylene derivative (C1) is 9 or less. <1> or <2> Treatment agent for carbon fiber precursors as described above. <4> Contains aromatic (poly)oxyalkylene derivatives (C2), <1> ~ <3> A treatment agent for carbon fiber precursors as described in any of the following. <5> The derivative (C2) includes a compound having a bisphenol skeleton. <4> Treatment agent for carbon fiber precursors as described above. <6> The proportion of the aryl group-containing silicone (B) in the non-volatile components of the treatment agent is 60% by weight or less. <1> ~ <5> A treatment agent for carbon fiber precursors as described in any of the following. <7> The silicone (B) having an aryl group includes the silicone (B1) having a phenyl group. <1> ~ <6> A treatment agent for carbon fiber precursors as described in any of the following. <8> The silicone (B) having the aryl group includes at least one selected from methylphenyl silicone and diphenyl silicone. <1> ~ <7> A treatment agent for carbon fiber precursors as described in any of the following. <9> The molar ratio (phenyl group:methyl group) of phenyl groups to methyl groups in the methylphenyl silicone and the diphenyl silicone is 1:99 to 90:10. <8> Treatment agent for carbon fiber precursors as described above. <10> The proportion of silicone having polyether groups in the nonvolatile components of the aforementioned treatment agent is 0 to 10% by weight. <1> ~ <9> A treatment agent for carbon fiber precursors as described in any of the following. <11> The pH of a 1.0% by weight dilution of the non-volatile content is 4-8. <1> ~ <10> A treatment agent for carbon fiber precursors as described in any of the following. <12> The raw material for carbon fiber precursors is, <1> ~ <11> A carbon fiber precursor to which a carbon fiber precursor treatment agent described in any of the above has been attached. <13> <12> A method for producing carbon fibers, comprising a flame-retardant treatment step of converting the carbon fiber precursor described above into flame-retardant fibers, and a carbonization treatment step of further carbonizing the flame-retardant fibers. [Effects of the Invention]

[0008] The carbon fiber precursor treatment agent of the present invention can suppress the deterioration of carbon fiber precursors even when the carbon fiber precursors produced with the treatment agent are stored for a long period of time, and carbon fibers with excellent physical properties can be obtained even when using carbon fiber precursors that have been stored for a long period of time. The carbon fiber precursor and carbon fiber manufacturing method of the present invention can produce carbon fibers with excellent physical properties even when using a carbon fiber precursor that has been stored for a long period of time. [Modes for carrying out the invention]

[0009] The components of the carbon fiber precursor treatment agent (hereinafter sometimes simply referred to as the treatment agent) of the present invention will now be described. [Silicone containing amino groups (A)] The treatment agent of the present invention contains an amino group-containing silicone (A). The amino group-containing silicone (A) is not particularly limited as long as the main chain is an inorganic siloxane bond (-Si-O-Si-) and has an organic group having an amino group in the side chain and / or terminal. Examples of amino group-containing silicone (A) include amino-modified silicone and amino polyether-modified silicone, and it is more preferable to include amino-modified silicone in order to achieve the effects of the present invention. Furthermore, aminopolyether-modified silicone is a silicone having amino groups (including organic groups having amino groups) and polyether groups (including organic groups having polyoxyalkylene groups). Known amino-modified silicones and aminopolyether-modified silicones can be used. One or more types of silicone (A) having amino groups may be used.

[0010] The kinematic viscosity at 25°C of the silicone (A) having an amino group is 50 to 20,000 mm 2 / s, which is preferable in terms of uniform adhesion to fibers, suppression of scattering of the treating agent, and imparting of fiber bundling properties. The upper limit of the kinematic viscosity is more preferably 15,000 mm 2 / s, still more preferably 12,000 mm 2 / s, particularly preferably 10,000 mm 2 / s. On the other hand, the lower limit of the kinematic viscosity is more preferably 100 mm 2 / s, still more preferably 150 mm 2 / s, particularly preferably 200 mm 2 / s. Also, for example, 100 to 15,000 mm 2 / s is more preferable, and 150 to 10,000 mm 2 / s is still more preferable.

[0011] The amino group (including an organic group having an amino group), which is a modifying group of the silicone (A) having an amino group, may be bonded to the side chain of the silicone as the main chain, may be bonded to the terminal, or may be bonded to both. However, from the viewpoint of fiber protection in the flame-retardant treatment step, it is preferable that it is bonded to the side chain (having an amino group in the side chain). Further, the amino group may be any of a monoamine type, a diamine type, and a polyamine type, and both may coexist in one molecule. However, from the point of uniformly applying the treating agent to the inside of the fiber bundle in the flame-retardant treatment step and forming a film of the treating agent to protect the fiber, the monoamine type or the diamine type is preferable, and the diamine type is more preferable.

[0012] The amino equivalent of the silicone (A) having an amino group is preferably 300 to 10,000 g / mol from the viewpoint of preventing adhesion and fusion between fibers. The upper limit of the amino equivalent is more preferably 9,500 g / mol, still more preferably 9,000 g / mol, and particularly preferably 8,000 g / mol. On the other hand, the lower limit of the amino equivalent is more preferably 500 g / mol, still more preferably 1,000 g / mol, and particularly preferably 1,500 g / mol. Also, for example, 500 to 9, (此处原文似乎有误,推测为9000)000 g / mol is more preferable, and 1,000 to 8,000 g / mol is still more preferable. Here, amino equivalent refers to the mass of the siloxane skeleton per amino group or ammonium group. The unit g / mol is the value converted to 1 mole of amino groups or ammonium groups. Therefore, a smaller amino equivalent value indicates a higher proportion of amino groups or ammonium groups within the molecule.

[0013] The amino group-containing silicone (A) may be a combination of multiple amino group-containing silicones with different amino equivalents and kinematic viscosities (at 25°C). When using two or more amino group-containing silicones, the above amino equivalent refers to the total amino equivalent of the amino group-containing silicone (A) (mixture), and the above kinematic viscosity at 25°C refers to the total kinematic viscosity of the amino group-containing silicone (A) (mixture).

[0014] Examples of silicones (A) having an amino group include the compound shown in the following general formula (1).

[0015] [ka] (In formula (1), R 1 R represents an alkyl group with 1 to 20 carbon atoms. 2 R is the group represented by the following general formula (2). 3 R 1 , R 2 OR 9 (R 9 (where is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). a is 1 ≤ a ≤ 10000, and b is 0 ≤ b ≤ 1000. However, if b = 0, R 3 At least one of these is a base represented by the following general formula (2). The order of each repeating unit enclosed by a and b is not limited, and the mode of association may be alternating, block-like, or random.

[0016] In formula (1), R 1 The R groups are preferably alkyl groups having 1 to 10 carbon atoms, more preferably alkyl groups having 1 to 5 carbon atoms, and even more preferably methyl groups.1 They may be the same or different. 3 R 1 , R 2 OR 9 The group is represented by , preferably R 1 Therefore, the multiple R in equation (1) 9 They may be the same or different. R 9 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. a is a number from 1 to 10000, preferably 30 to 5000, and more preferably 50 to 2000. b is a number from 0 to 1000, preferably 1 to 500, and more preferably 2 to 100.

[0017] [ka]

[0018] In formula (2), R 4 and R 6 Each of these is independently an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms. 5 , R 7 and R 8 Each of these is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom. c is a number from 0 to 6, preferably 0 to 3, and more preferably 0 to 1.

[0019] [Silicone containing aryl groups (B)] The treatment agent of the present invention contains a silicone (B) having an aryl group. The silicone (B) having an aryl group has an inorganic siloxane bond (-Si-O-Si-) in its main chain and has aryl groups in its side chains and / or terminals, and is not particularly limited as long as it is not a silicone (A) having an amino group. The aryl group in the aryl-containing silicone (B) is not particularly limited, but examples include phenyl group, aralkyl group, naphthyl group, tolyl group, xylyl group, etc. In order to achieve the effects of the present invention, it is preferable to include one selected from phenyl group and aralkyl group, and more preferable to include phenyl group. One or more types of aryl-containing silicone (B) may be used.

[0020] The kinematic viscosity of silicone (B) containing an aryl group at 25°C is 10-20,000 mm², which is desirable in terms of uniform adhesion to fibers and suppression of treatment agent scattering. 2 / s is preferred. The upper limit of the kinematic viscosity is (1) 15,000 mm 2 / s, (2) 10000mm 2 / s, (3) 8000mm 2 / s, (4) 1000mm 2 / s, (5) 495mm 2 / s, (6) 295mm 2 The order of preference is / s (a larger number in parentheses is preferable). On the other hand, the lower limit of the kinematic viscosity is (1) 30 mm 2 / s, (2) 50mm 2 / s, (3) 55mm 2 / s, (4) 70mm 2 / s, (4) 100mm 2 The order / s is preferable (a larger number in parentheses is preferable). Also, for example, 30~8000mm 2 / s is more preferable, 50-1000mm 2 / s is even more preferable, 55~495mm 2 / s is particularly preferred, 55~295mm 2 / s is the most preferred option.

[0021] The aryl group, which is the modifying group of silicone (B) having an aryl group, may be bonded to the side chain of the main chain silicone, to the end, or to both. However, from the viewpoint of protecting the fibers in the flame-retardant treatment process, it is preferable that it is bonded to the side chain (the side chain has an aryl group).

[0022] The silicone (B) having an aryl group is preferably composed of a silicone (B1) having a phenyl group, preferably methylphenyl silicone, and preferably diphenyl silicone, with diphenyl silicone being more preferable in terms of emulsification stability. Methylphenyl silicone is a methylphenylsiloxane unit ((CH3)(C6H5)SiO 2 / 2 ) and dimethylsiloxane units ((CH3)2SiO 2 / 2 Examples of silicones include those having a diphenylsiloxane unit ((C6H5)2SiO 2 / 2 ) and dimethylsiloxane units ((CH3)2SiO 2 / 2 Examples of silicones include those having )

[0023] The molar ratio (phenyl groups:methyl groups) of phenyl groups to methyl groups in methylphenyl silicone and diphenyl silicone is not particularly limited, but in terms of emulsification stability, 1:99 to 90:10 is preferred, 1:99 to 70:30 is more preferred, 1:99 to 50:50 is even more preferred, and 1:99 to 30:70 is particularly preferred.

[0024] The silicone (B) having an aryl group may be a combination of multiple silicones having different kinematic viscosities (at 25°C). When using two or more silicones having aryl groups, the kinematic viscosity at 25°C mentioned above refers to the kinematic viscosity of the entire (mixture) of the silicone (B) having an aryl group.

[0025] [Aliphatic (poly)oxyalkylene derivatives (C1)] The treatment agent of the present invention contains an aliphatic (poly)oxyalkylene derivative (C1) (hereinafter sometimes referred to as aliphatic derivative (C1)). The aliphatic derivative (C1) is not particularly limited as long as it is an aliphatic compound having a (poly)oxyalkylene group, but examples include aliphatic alcohol alkylene oxide adducts (C1-1) and aliphatic alkylene oxide adducts having an ester group (C1-2), with aliphatic alcohol alkylene oxide adducts (C1-1) being preferred in terms of emulsification stability. One or more aliphatic (poly)oxyalkylene derivatives (C1) may be used.

[0026] Examples of aliphatic alcohol alkylene oxide adducts (C1-1) include alkylene oxide adducts of aliphatic alcohols that do not contain an ester group. The aliphatic alcohol constituting the aliphatic alcohol alkylene oxide adduct (C1-1) is not particularly limited, but examples include aliphatic alcohols having 2 to 24 carbon atoms. The aliphatic alcohol may be saturated or unsaturated, linear or branched, and monohydric or dihydric or multihydric. In terms of emulsification stability, monohydric linear saturated aliphatic alcohols and monohydric branched saturated aliphatic alcohols are preferred. One or more types of aliphatic alcohol alkylene oxide adducts (C1-1) may be used. The upper limit of the aliphatic alcohol's carbon number is preferably 20, more preferably 18, and even more preferably 16. On the other hand, the lower limit of the carbon number is more preferably 4, even more preferably 6, and particularly preferably 8. Also, for example, 6 to 18 is preferred, and 8 to 16 is more preferred.

[0027] Examples of aliphatic alcohols that constitute the aliphatic alcohol alkylene oxide adduct (C1-1) include butyl alcohol, octyl alcohol, nonanol, lauryl alcohol, stearyl alcohol, cetyl alcohol, isobutyl alcohol, 2-ethylhexyl alcohol, isododecyl alcohol, isohexadecyl alcohol, isostearyl alcohol, isotetracosanyl alcohol, 12-eicosyl alcohol, vinyl alcohol, butenyl alcohol, hexadecenyl alcohol, oleyl alcohol, eicocenyl alcohol, linear secondary alcohols having 10 to 16 carbon atoms, glycerin, trimethylolpropane, sorbitol, ethylene glycol, propylene glycol, and butylene glycol. In terms of emulsification stability, lauryl alcohol, stearyl alcohol, isododecyl alcohol, isohexadecyl alcohol, isostearyl alcohol, and linear secondary alcohols having 10 to 16 carbon atoms are preferred, and linear secondary alcohols having 10 to 16 carbon atoms are more preferred.

[0028] The number of moles of alkylene oxide added to the aliphatic alcohol alkylene oxide adduct (C1-1) is preferably 2 to 50 moles. The upper limit of the number of moles added is more preferably 40 moles, even more preferably 30 moles, and particularly preferably 20 moles. On the other hand, the lower limit of the number of moles added is more preferably 3 moles, even more preferably 4 moles, and particularly preferably 5 moles. Also, for example, 3 to 40 moles is more preferably, and 5 to 20 moles is particularly preferably. The alkylene oxide preferably contains at least one selected from ethylene oxide and propylene oxide, and more preferably contains ethylene oxide. The alkylene oxide may be added randomly or in a blocked manner.

[0029] Aliphatic alcohol alkylene oxide adducts (C1-1) include, specifically, polyoxyethylene hexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene tetradecyl ether, polyoxyethylene cetyl ether, polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isocetyl ether, polyoxyethylene isostearyl ether, polyoxyethylene 1-hexylhexyl ether, and polio Examples include oxyethylene 1-octylhexyl ether, polyoxyethylene 1-hexyloctyl ether, polyoxyethylene 1-pentylheptyl ether, polyoxyethylene 1-heptylpentyl ether, polyoxyethylene 1-hexylheptyl ether, polyoxyethylene 1-heptylhexyl ether, polyoxyethylene 1-pentylcaptyl ether, polyoxyethylene 1-capylpentyl ether, polyoxyethylene oleyl ether, linear secondary alcohol ethoxylates having 10 to 16 carbon atoms, oxyethylene-oxypropylene blocks, or random copolymers.

[0030] Examples of aliphatic alkylene oxide adducts (C1-2) having an ester group include those with a structure in which alkylene oxide is added to an aliphatic carboxylic acid (C1-2-1) and those with a structure in which alkylene oxide is added to an ester compound of an aliphatic carboxylic acid and a polyhydric alcohol (C1-2-2). One or more types of aliphatic alkylene oxide adducts (C1-2) having an ester group may be used.

[0031] The aliphatic carboxylic acid constituting the aliphatic alkylene oxide adduct (C1-2) having an ester group is not particularly limited, but examples include aliphatic monocarboxylic acids with 4 to 24 carbon atoms and aliphatic polycarboxylic acids with 4 to 24 carbon atoms. The aliphatic carboxylic acid may be saturated or unsaturated, and may be linear or branched.

[0032] Examples of aliphatic monocarboxylic acids having 4 to 24 carbon atoms include pentanoic acid, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, octicic acid, decanoic acid, dodecanoic acid (lauric acid), tridecanoic acid, isotridecanoic acid, hexadecanoic acid, octadecanoic acid (stearic acid), isooctadecanoic acid (isostearic acid), hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid (12-hydroxystearic acid), octadecenoic acid, hydroxyoctadecenoic acid, octadecadienoic acid, octadecatrienoic acid, docosanic acid (behenic acid), tetracosanic acid, hexacosanic acid, octadocosanoic acid, octacosanic acid, ricinoleic acid, oleic acid, isostearic acid, and isoarachinic acid. In terms of emulsification stability, dodecanoic acid, oleic acid, and isostearic acid are preferred.

[0033] In aliphatic alkylene oxide adducts (C1-2) having an ester group, the number of moles of alkylene oxide added is preferably 2 to 50 moles. The upper limit of the number of moles added is more preferably 40 moles, even more preferably 30 moles, and particularly preferably 20 moles. On the other hand, the lower limit of the number of moles added is more preferably 3 moles, even more preferably 4 moles, and particularly preferably 5 moles. Also, for example, 3 to 40 moles is more preferably, and 5 to 20 moles is particularly preferably. The alkylene oxide preferably contains at least one selected from ethylene oxide and propylene oxide, and more preferably contains ethylene oxide. The alkylene oxide may be added randomly or in a blocked manner.

[0034] Examples of structures in which an alkylene oxide is added to an aliphatic carboxylic acid (C1-2-1) include the compounds obtained by adding an alkylene oxide to the aliphatic carboxylic acid mentioned above, and in terms of emulsification stability, structures in which 1 to 20 moles of ethylene oxide are added to a carboxylic acid having 8 to 18 carbon atoms are preferred.

[0035] The polyhydric alcohol constituting the structure (C1-2-2) obtained by adding an alkylene oxide to an ester compound of an aliphatic carboxylic acid and a polyhydric alcohol is preferably a dihydric to tetrahydric alcohol having 2 to 6 carbon atoms, and among these, dihydric to trihydric alcohols having 2 to 6 carbon atoms are more preferred. Specifically, examples of such polyhydric alcohols include dihydric alcohols such as propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, and 1,6-hexanediol, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric or higher alcohols such as pentaerythritol, sorbitan, and sorbitol.

[0036] Examples of structures (C1-2-2) in which an alkylene oxide is added to an ester compound of an aliphatic carboxylic acid and a polyhydric alcohol include the compounds obtained by adding an alkylene oxide to the ester compounds of aliphatic carboxylic acids and polyhydric alcohols mentioned above. In terms of emulsification stability, alkylene oxide adducts of glycerin fatty acid esters and alkylene oxide adducts of sorbitan fatty acid esters are preferred.

[0037] [Aromatic (poly)oxyalkylene derivatives (C2)] The treatment agent of the present invention may contain an aromatic (poly)oxyalkylene derivative (C2) (hereinafter sometimes referred to as aromatic derivative (C2)). The aromatic derivative (C2) is not particularly limited as long as it is an aromatic compound having a (poly)oxyalkylene group. Examples include alkylene oxide adducts of aromatic compounds having a hydroxyl group (C2-1) and aromatic alkylene oxide adducts having an ester group (C2-2). The alkylene oxide adduct of aromatic compounds having a hydroxyl group (C2-1) is preferred in that it improves the convergence during flame resistance. Note that the alkylene oxide adduct of aromatic compounds having a hydroxyl group (C2-1) does not have an ester group. Aromatic derivatives (C2) are preferably compounds containing a bisphenol skeleton because they have high heat resistance and can improve the convergence properties when flame-retardant.

[0038] The aromatic compound having a hydroxyl group that constitutes the alkylene oxide adduct (C2-1) of the aromatic compound having a hydroxyl group is not particularly limited, but examples include compounds having a bisphenol skeleton, (poly)styrene-modified phenols, alkylphenols, etc. Compounds having a bisphenol skeleton are preferred in terms of improving the convergence during flame resistance, and compounds having a bisphenol A skeleton are more preferred. In the alkylene oxide adduct (C2-1) of an aromatic compound having a hydroxyl group, the number of moles of alkylene oxide added is preferably 2 to 60 moles. The upper limit of the number of moles added is more preferably 40 moles, even more preferably 30 moles, and particularly preferably 20 moles. On the other hand, the lower limit of the number of moles added is more preferably 4 moles, even more preferably 6 moles, and particularly preferably 8 moles. Also, for example, 4 to 40 moles is more preferably, and 6 to 30 moles is particularly preferably. The alkylene oxide added to the aromatic compound having a hydroxyl group is preferably at least one selected from ethylene oxide and propylene oxide, more preferably containing ethylene oxide, and even more preferably ethylene oxide.

[0039] The alkylene oxide adduct (C2-1) of the aromatic compound having a hydroxyl group is not limited as long as it is obtained by adding an alkylene oxide to the above aromatic compound having a hydroxyl group, but bisphenol A alkylene oxide adduct, styrene-phenol alkylene oxide adduct, and polystyrene-phenol alkylene oxide adduct are preferred, and bisphenol A alkylene oxide adduct is more preferred.

[0040] Examples of aromatic alkylene oxide adducts (C2-2) having an ester group include esters (C2-2-1) of an alkylene oxide adduct of an aromatic compound having a hydroxyl group and a carboxylic acid. There are no particular limitations on the alkylene oxide adduct of the aromatic compound having a hydroxyl group that constitutes the ester (C2-2-1) of the alkylene oxide adduct of the aromatic compound having a hydroxyl group with a carboxylic acid, but the alkylene oxide adduct (C2-1) of the aromatic compound having a hydroxyl group described above is preferred. Examples of carboxylic acids that constitute an ester of an alkylene oxide adduct of an aromatic compound having a hydroxyl group and a carboxylic acid include aliphatic carboxylic acids and aromatic carboxylic acids, with aliphatic carboxylic acids being preferred in terms of improving the convergence properties during flame resistance.

[0041] There are no particular limitations on the aliphatic carboxylic acid, but examples include aliphatic monocarboxylic acids with 4 to 24 carbon atoms and aliphatic polycarboxylic acids with 4 to 24 carbon atoms. The aliphatic carboxylic acid may be saturated or unsaturated, and may be linear or branched. There may be one or more types of aliphatic carboxylic acids.

[0042] Examples of aliphatic monocarboxylic acids having 4 to 24 carbon atoms include pentanoic acid, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, octicic acid, decanoic acid, dodecanoic acid (lauric acid), tridecanoic acid, isotridecanoic acid, hexadecanoic acid, octadecanoic acid (stearic acid), isooctadecanoic acid (isostearic acid), hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid (12-hydroxystearic acid), octadecenoic acid, hydroxyoctadecenoic acid, octadecadienoic acid, octadecatrienoic acid, docosanic acid (behenic acid), tetracosanic acid, hexacosanic acid, octadocosanoic acid, octacosanic acid, ricinoleic acid, oleic acid, isostearic acid, isoarachinic acid, etc., and decanoic acid, dodecanoic acid, tridecanoic acid, and oleic acid are preferred in terms of emulsification stability.

[0043] Examples of aliphatic polycarboxylic acids having 4 to 24 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, and citraconic acid. Succinic acid and adipic acid are preferred in terms of emulsification stability.

[0044] There are no particular limitations on aromatic carboxylic acids, but examples include aromatic polycarboxylic acids with 8 to 40 carbon atoms and aromatic monocarboxylic acids with 7 to 14 carbon atoms. Aromatic polycarboxylic acids having 8 to 40 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, diphenyl ether dicarboxylic acid, naphthalenedicarboxylic acid, phenylmalonic acid, phenylsuccinic acid, β-phenylglutaric acid, α-phenyladipic acid, β-phenyladipic acid, biphenyl-2,2'- or 4,4'-dicarboxylic acid, naphthalenedicarboxylic acid, sodium 5-sulfoisophthalate and potassium 5-sulfoisophthalate, and derivatives of these dicarboxylic acids, as well as trimellitic acid, pyromellitic acid, and derivatives of these trivalent or higher carboxylic acids. Examples of aromatic monocarboxylic acids with 7 to 14 carbon atoms include benzoic acid. The aromatic carboxylic acid may be one type or two or more types.

[0045] There are no particular limitations on the esters of alkylene oxide adducts of aromatic compounds having hydroxyl groups and carboxylic acids, but examples include esters of bisphenol A with 1 to 20 moles of polyoxyalkylene and fatty acids, and esters of distyleninated phenol with 1 to 20 moles of polyoxyalkylene and fatty acids. In terms of improving the convergence properties during flame resistance, esters of bisphenol A with 1 to 20 moles of polyoxyethylene and fatty acids are preferred.

[0046] [Brønsted acid compounds (D)] The treatment agent of the present invention is preferable in that its emulsification stability is improved when it contains a Brønsted acid compound (D). A Brønsted acid compound (D) is a proton donor and includes organic carboxylic acid compounds, inorganic acids, organic sulfonic acid compounds, organic phosphate ester compounds, organic sulfuric acid ester compounds, and organic phosphonic acid compounds.

[0047] Organic carboxylic acid compounds are organic compounds that have a carboxyl group in their molecular structure. Examples of organic carboxylic acid compounds are not particularly limited, but include aliphatic monocarboxylic acids, alkyl ether carboxylic acids, aliphatic polycarboxylic acids, aromatic carboxylic acids, aromatic polycarboxylic acids, and amino acids.

[0048] Examples of aliphatic monocarboxylic acids include acetic acid, lactic acid, butyric acid, crotonic acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, myristoleic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, isocetyl acid, margaric acid, stearic acid, isostearic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linolenic acid, arachidic acid, isoeicosacid, gadoleic acid, eicosenoic acid, docosanic acid, isodocosanic acid, erucic acid, tetracosanic acid, isotetracosanic acid, nervonic acid, cerotic acid, montanic acid, and melissic acid.

[0049] Examples of alkyl ether carboxylic acids include those in which the alkyl group has 8 to 18 carbon atoms and the number of moles of polyoxyalkylene added is 1 to 50 moles. Examples of the alkyl group include octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups. Examples of the polyoxyalkylene group include polyoxyethylene, polyoxypropylene, and polyoxyethylene-polyoxypropylene.

[0050] Examples of aliphatic polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superiric acid, azelaic acid, sebatic acid, undencanedioic acid, dodecanediic acid, tridecanediic acid, tetradecanediic acid, pentadecanediic acid, and their derivatives.

[0051] Examples of aromatic monocarboxylic acids include benzoic acid, cinnamic acid, naphthoic acid, toluic acid, and their derivatives.

[0052] Examples of aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and their derivatives.

[0053] Amino acids are compounds that have both an amino group and a carboxyl group in their molecular structure, and examples include alanine, valine, leucine, isoleucine, phenylalanine, tryptophan, methionine, proline, glycine, tyrosine, serine, threonine, cysteine, asparagine, glutamine, lysine, arginine, histidine, aspartic acid, and glutamic acid.

[0054] Inorganic acids are acids whose components are nonmetallic atoms. Examples of inorganic acids include sulfuric acid, nitric acid, phosphoric acid, and hydrochloric acid.

[0055] Examples of organic sulfonic acid compounds include alkylbenzene sulfonic acid, polyoxyalkylene alkyl ether sulfonic acid, higher fatty acid amide sulfonic acid, alkyl sulfate monoester, and polyoxyalkylene sulfate monoester.

[0056] Examples of organic phosphate ester compounds include alkyl phosphate monoesters, alkyl phosphate diesters, polyoxyalkylene alkyl ether phosphate monoesters, polyoxyalkylene alkyl ether phosphate diesters, polyoxyalkylene alkylphenyl ether phosphate monoesters, and polyoxyalkylene alkylphenyl ether phosphate diesters.

[0057] Examples of organic sulfate ester compounds include alkyl sulfates, polyoxyalkylene alkyl sulfates, alkylphenyl sulfates, and polyoxyalkylene alkylphenyl sulfates.

[0058] Examples of organic phosphonic acid compounds include alkylphosphonic acids, aromatic phosphonic acids, and polyoxyalkylene alkyl ether phosphonic acids.

[0059] The pKa of the Brønsted acid compound (D) is preferably 0 to 7, more preferably 1 to 6.5, and even more preferably 2 to 6, from the viewpoint of equipment corrosion, safety, and suppression of crosslinking over time caused by the amino groups of the amino-modified silicone.

[0060] The Brønsted acid compound (D) preferably contains at least one selected from organic carboxylic acid compounds, inorganic acids, and organic phosphate ester compounds, in terms of improving emulsification stability, more preferably contains at least one selected from lactic acid, alkyl ether carboxylic acid, organic phosphate ester compounds, phosphoric acid, and acetic acid, and even more preferably contains at least one selected from alkyl ether carboxylic acid, organic phosphate ester compounds, acetic acid, and phosphoric acid. One or more Brønsted acid compounds (D) may be used.

[0061] [Silicone containing polyether groups] The treatment agent of the present invention contains a silicone having a polyether group. You may A silicone having a polyether group is one in which the main chain has an inorganic siloxane bond (-Si-O-Si-) and has a polyether group in at least one of the main chain, side chains, and terminals, and is not particularly limited as long as it is not a silicone having an amino group (A). As the silicone having a polyether group, any known silicone having a polyether group can be used as appropriate. Examples of silicones having a polyether group include ABn-type polyether-modified silicone, side-chain type polyether-modified silicone, double-ended type polyether-modified silicone, alkyl polyether-modified silicone in which both a polyether group and an alkyl group are introduced to the side chain or terminal, a side-chain type polyether-modified silicone in which the polyether chain terminal portion is sealed with an aliphatic compound or fatty acid compound, and a double-ended type polyether-modified silicone in which the polyether chain terminal portion is sealed with an aliphatic compound or fatty acid compound. One or more types of silicones having a polyether group may be used.

[0062] The weight ratio of the total weight of oxypropylene (hereinafter sometimes referred to as PO) units and oxyethylene (hereinafter sometimes referred to as EO) units to the weight of the polyether group-containing silicone is preferably 5 to 95% by weight, from the viewpoint of penetration into the fiber bundle and the stability of the treatment agent in an aqueous system. The upper limit of this ratio is more preferably 90% by weight, even more preferably 85% by weight, and particularly preferably 80% by weight. On the other hand, the lower limit of this ratio is more preferably 10% by weight, even more preferably 15% by weight, and particularly preferably 20% by weight. For example, 10 to 95% by weight is more preferably, 15 to 95% by weight is even more preferably, and 20 to 90% by weight is particularly preferred.

[0063] The weight ratio of EO units to PO units (EO / PO) in the polyether-containing silicone is preferably 0.05 to 95 in terms of penetration into the fiber bundle. The upper limit of this ratio is more preferably 75, even more preferably 50, and particularly preferably 20. On the other hand, the lower limit of this ratio is more preferably 0.1, even more preferably 0.3, and particularly preferably 1.0. Also, for example, 0.1 to 50 is more preferably, and 0.1 to 20 is even more preferably. Here, the total ratio of PO units and EO units in the polyether-containing silicone, and the weight ratio of EO units to PO units contained in the polyether-containing silicone (EO / PO), refer to the total weight ratio of all PO units and EO units contained in the polyether-containing silicone. 1 This refers to the ratio of PO units to EO units relative to the weight of the polyether group-containing silicone, calculated from the peak area obtained by 1H-NMR.

[0064] The HLB (Hydrophile-Lipophile Balance) value, which is expressed as the hydrophilic-lipophilic balance of a silicone having a polyether group, is not particularly limited, but is preferably 4 to 16 from the viewpoint of the stability of the treatment agent in an aqueous system. The upper limit of the HLB is more preferably 15, even more preferably 14, and particularly preferably 12. On the other hand, the lower limit of the HLB is more preferably 6, even more preferably 7, and particularly preferably 8. Also, for example, is more preferably 7 to 16, and even more preferably 7 to 14. In this invention, HLB is a value obtained from the cloud number A, which is measured as follows, using the following formula. HLB=cloud number A×0.89+1.11 <Method for measuring cloudiness level A> The cloudiness number A is measured as follows, in accordance with the known method described in "Handbook of Surfactants, pp. 324-325 (Sangyo Tosho Co., Ltd., published July 5, 1960)". Weigh 2.5 g of anhydrous polyether-containing silicone and add 98% ethanol to a total volume of 25 ml (using a 25 ml volumetric flask). Next, dispense this mixture using a 5 ml volumetric pipette and place it in a 50 ml beaker. Maintain the temperature at 25°C and measure the titration using a 25 ml burette with 2% phenol aqueous solution while stirring (using a magnetic stirrer). The endpoint is reached when the solution becomes turbid, and the number of ml of 2% phenol aqueous solution required for this titration is defined as the cloudiness number A.

[0065] The kinematic viscosity of silicones containing polyether groups at 25°C is 10 to 10,000 mm in terms of penetration into the fiber bundle. 2 / s is preferred. The upper limit of the kinematic viscosity is more preferably 8000 mmHg. 2 / s, more preferably 7000mm 2 / s, particularly preferably 5000mm 2 The value is / s. On the other hand, the lower limit of the kinematic viscosity is more preferably 50 mm 2 / s, more preferably 100mm 2 / s, especially preferably 150mm 2 It is / s. Also, for example, 50~5000mm 2 / s is more preferable, 100~5000mm 2 / s is even preferable.

[0066] Silicones containing polyether groups may be used in combination with multiple silicones containing polyether groups having different HLB and kinematic viscosity (at 25°C). When using two or more silicones containing polyether groups, the above HLB refers to the HLB of the entire (mixture) of the silicones containing polyether groups, and the above kinematic viscosity at 25°C refers to the kinematic viscosity of the entire (mixture) of the silicones containing polyether groups.

[0067] [Treatment agent for carbon fiber precursors] The carbon fiber precursor treatment agent of the present invention contains an amino group-containing silicone (A), an aryl group-containing silicone (B), and an aliphatic (poly)oxyalkylene derivative (C1).

[0068] The reason why the carbon fiber precursor treatment agent of the present invention contains an amino group-containing silicone (A), an aryl group-containing silicone (B), and an aliphatic (poly)oxyalkylene derivative (C1) is that when the carbon fiber precursor produced by applying the treatment agent is stored for a long period of time, the deterioration of the carbon fiber precursor can be suppressed. This is thought to be because the aryl group-containing silicone (B) and the aliphatic (poly)oxyalkylene derivative (C1) form a protective layer on the surface of the carbon fiber precursor, suppressing crosslinking over time caused by the oxidation of the amino group of the amino group-containing silicone (A).

[0069] The proportion of amino group-containing silicone (A) in the nonvolatile content of the treatment agent of the present invention is preferably 0.1 to 95% by weight, in terms of easily suppressing the deterioration of the carbon fiber precursor over time and facilitating emulsification stabilization. The upper limit of this proportion is more preferably 92% by weight, even more preferably 88% by weight, and particularly preferably 85% by weight. On the other hand, the lower limit of this proportion is more preferably 1% by weight, even more preferably 3% by weight, and particularly preferably 5% by weight. Furthermore, for example, 1 to 92% by weight is more preferable, 3 to 88% by weight is even more preferable, and 5 to 85% by weight is particularly preferable. In this invention, the non-volatile content concentration is obtained by spreading 2.0 to 3.0 g of the treatment agent flat on an aluminum sheet (φ110 mm), drying it at 110°C under infrared lamp irradiation, accurately weighing the weight of the remaining portion on the aluminum sheet when the fluctuation range of the volatile content over 150 seconds reaches 0.15%, and calculating the ratio (percentage) of the remaining weight after heating to the weight before heating. In this invention, the non-volatile content refers to the remaining portion on the aluminum sheet when the fluctuation range of the volatile content over 150 seconds reaches 0.15%, as measured in the same procedure as for measuring the non-volatile content concentration.

[0070] The proportion of aryl group-containing silicone (B) in the nonvolatile content of the treatment agent of the present invention is preferably 60% by weight or less, in terms of easily suppressing the deterioration of the carbon fiber precursor over time and easily stabilizing the emulsion. The upper limit of this proportion is more preferably 50% by weight, even more preferably 30% by weight, and particularly preferably 15% by weight. On the other hand, the lower limit of this proportion is more preferably 0.5% by weight, even more preferably 1% by weight, and particularly preferably 1.5% by weight. Furthermore, for example, 0.5 to 50% by weight is more preferable, 1 to 30% by weight is even more preferable, and 1.5 to 15% by weight is particularly preferable.

[0071] The proportion of aliphatic (poly)oxyalkylene derivative (C1) in the nonvolatile content of the treatment agent of the present invention is preferably 1 to 90% by weight, in terms of easily suppressing the deterioration of the carbon fiber precursor over time and facilitating emulsification stabilization. The upper limit of this proportion is more preferably 70% by weight, even more preferably 40% by weight, and particularly preferably 30% by weight. On the other hand, the lower limit of this proportion is more preferably 3% by weight, even more preferably 5% by weight, and particularly preferably 7% by weight. Furthermore, for example, 3 to 70% by weight is more preferable, 5 to 40% by weight is even more preferable, and 7 to 30% by weight is particularly preferable.

[0072] The weight ratio (B / A) of aryl group-containing silicone (B) to amino group-containing silicone (A) is preferably 1 or less, in terms of suppressing degradation of the carbon fiber precursor over time and facilitating emulsification. The upper limit of this ratio is more preferably 0.9, even more preferably 0.7, particularly preferably 0.5, and most preferably 0.48. On the other hand, the lower limit of this weight ratio is more preferably 0.005, even more preferably 0.008, and particularly preferably 0.01. Furthermore, for example, 0.005 to 0.9 is more preferable, 0.008 to 0.7 is even more preferable, 0.01 to 0.5 is particularly preferable, and 0.01 to 0.48 is most preferable.

[0073] The weight ratio (B / C1) of the aryl group-containing silicone (B) to the aliphatic (poly)oxyalkylene derivative (C1) is preferably 9 or less, in terms of suppressing the degradation of the carbon fiber precursor over time and facilitating emulsification. The upper limit of this ratio is more preferably 7, even more preferably 5, particularly preferably 4, and most preferably 1.7. On the other hand, the lower limit of this weight ratio is more preferably 0.01, even more preferably 0.05, and particularly preferably 0.1. Furthermore, for example, 0.01 to 7 is more preferable, 0.05 to 5 is even more preferable, 0.1 to 4 is particularly preferable, and 0.1 to 1.7 is most preferable.

[0074] When the treatment agent of the present invention further contains a Brønsted acid compound (D), the proportion of the Brønsted acid compound (D) in the nonvolatile content of the treatment agent of the present invention is preferably 0.05 to 10% by weight, in terms of ease of emulsification stabilization. The upper limit of this weight percentage is more preferably 8.5% by weight, even more preferably 7% by weight, and particularly preferably 5% by weight. On the other hand, the lower limit of this weight percentage is more preferably 0.07% by weight, even more preferably 0.08% by weight, and particularly preferably 0.1% by weight. Also, for example, 0.07 to 7% by weight is more preferable, and 0.1 to 5% by weight is even more preferable.

[0075] The proportion of silicone having polyether groups in the nonvolatile content of the treatment agent of the present invention is preferably 0 to 10% by weight, as this facilitates emulsification stabilization. The upper limit of this weight percentage is more preferably 8.5% by weight, even more preferably 7% by weight, and particularly preferably 5% by weight. On the other hand, the lower limit of this weight percentage is more preferably 0.07% by weight, even more preferably 0.08% by weight, and particularly preferably 0.1% by weight. For example, 0.07 to 7% by weight is more preferable, and 0.1 to 5% by weight is even more preferable.

[0076] [Other ingredients (E)] The treatment agent of the present invention preferably further contains other nonionic surfactants as other components (E) because it can enhance emulsification stability. Note that other nonionic surfactants refer to nonionic surfactants other than aliphatic (poly)oxyalkylene derivatives (C1) and aromatic (poly)oxyalkylene derivatives (C2). Other nonionic surfactants include sorbitan esters such as sorbitan monopalmitate and sorbitan monooleate; glycerin fatty acid esters such as glycerin monostearate, glycerin monolaurate, and glycerin monopalmitate; and sucrose fatty acid esters. The weight-average molecular weight of the other nonionic surfactants is preferably 2000 or less, more preferably 200 to 1800, more preferably 300 to 1500, and even more preferably 500 to 1000. One or more types of the other nonionic surfactants may be used.

[0077] When the treatment agent of the present invention contains other nonionic surfactants, the weight percentage of the other nonionic surfactants in the nonvolatile content of the treatment agent is preferably 0.1 to 10% by weight in terms of emulsification stability. The upper limit of this percentage is more preferably 8.5% by weight, even more preferably 7.0% by weight, and particularly preferably 5.0% by weight. On the other hand, the lower limit of this percentage is more preferably 0.25% by weight, even more preferably 0.4% by weight, and particularly preferably 0.5% by weight. Also, for example, 0.25 to 8.5% by weight is more preferable, 0.4 to 7.0% by weight is even more preferable, and 0.5 to 5.0% by weight is particularly preferable.

[0078] The pH of the treatment agent of the present invention, when diluted to 1.0% by weight of non-volatile content, is preferably 4 to 8 in terms of the long-term storage stability of the treatment agent. The upper limit of the pH is more preferably 7, and even more preferably 6.5. On the other hand, the lower limit of the content is more preferably 4.5, and even more preferably 5. Also, for example, 4.5 to 6.5 is more preferably, and even more preferably 5 to 6.5. The pH of the 1.0% non-volatile content diluted solution of the treatment agent in the present invention is determined by the method described in the examples.

[0079] [Other surfactants] The treatment agent of the present invention may contain surfactants other than aliphatic (poly)oxyalkylene derivatives (C1), aromatic (poly)oxyalkylene derivatives (C2), Brønsted acid compounds (D), and other nonionic surfactants, to the extent that they do not impair the effects of the present invention. Other surfactants are used as emulsifiers, antistatic agents, etc. The other surfactants are not particularly limited, and known surfactants can be appropriately selected and used from anionic surfactants, cationic surfactants, and amphoteric surfactants. One surfactant may be used, or two or more may be used in combination.

[0080] Examples of anionic surfactants include ether carboxylates, ether sulfates, sulfosuccinates, (poly)oxyethylene coconut oil fatty acid monoethanolamide sulfate sodium, alkyl-containing sulfonates, alkyl-containing phosphates, fatty acid salts, acylated amino acid salts, and amine neutralized fatty acids.

[0081] Examples of cationic surfactants include alkyl quaternary ammonium salts such as lauryltrimethylammonium chloride, myristyltrimethylammonium chloride, palmityltrimethylammonium chloride, stearyltrimethylammonium chloride, oleyltrimethylammonium chloride, cetyltrimethylammonium chloride, behenyltrimethylammonium chloride, coconut oil alkyltrimethylammonium chloride, beef tallow alkyltrimethylammonium chloride, stearyltrimethylammonium bromide, coconut oil alkyltrimethylammonium bromide, cetyltrimethylammonium methosulfate, oleyldimethylethylammonium ethosulfate, dioctyldimethylammonium chloride, dilauryldimethylammonium chloride, distearyldimethylammonium chloride, and octadecyldiethylmethylammonium sulfate; and N-(2-hydroxyethyl)-N,N-dimethyl-N-sulfate. Acylamide alkyl quaternary ammonium salts such as thearoylamidopropylammonium nitrate, lanolin fatty acid amidopropyl ethyldimethylammonium ethosulfate, and lauroylamidoethyl methyldiethylammonium methosulfate; alkylisoquinolinium salts such as laurylisoquinolinium chloride; benzalkonium salts such as lauryldimethylbenzylammonium chloride and stearyldimethylbenzylammonium chloride; pyridinium salts such as cetylpyridinium chloride; imidazolinium salts such as oleylhydroxyethylimidazolinium ethosulfate and laurylhydroxyethylimidazolinium ethosulfate; acyl basic amino acid alkyl ester salts such as N-cocoyl arginine ethyl ester pyrrolidone carboxylate and N-lauroyl lysine ethyl ester chloride; primary amine salts such as laurylamine chloride, stearylamine bromide, hydrogenated beef tallow alkylamine chloride, and rosinamine acetate;Examples include secondary amine salts such as cetylmethylamine sulfate, laurylmethylamine chloride, dilaurylamine acetate, stearylethylamine bromide, laurylpropylamine acetate, dioctylamine chloride, and octadecylethylamine hydroxide; tertiary amine salts such as dilaurylmethylamine sulfate, lauryldiethylamine chloride, laurylethylmethylamine bromide, diethanolstearylamideethylamine trihydroxyethyl phosphate salt, and stearylamideethylethanolamine urea bicondensate acetate; fatty acid amide guanidinium salts; and alkyltrialkylene glycol ammonium salts such as lauryltriethylene glycol ammonium hydroxide.

[0082] Examples of amphoteric surfactants include imidazoline-based amphoteric surfactants such as 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium and 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt; betaine-based amphoteric surfactants such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, lauryldimethylaminoacetic acid betaine, alkyl betaine, amide betaine, and sulfobetaine; and amino acid-type amphoteric surfactants such as N-laurylglycine, N-lauryl β-alanine, and N-stearyl β-alanine.

[0083] [Other ingredients] The carbon fiber precursor treatment agent of the present invention may contain other components besides those described above, as long as they do not impair the effects of the present invention. Examples of other components include antioxidants such as phenolic, amine, sulfur, phosphorus, and quinone-based agents; antistatic agents such as quaternary ammonium salt type cationic surfactants and amine salt type cationic surfactants; smoothing agents such as alkyl esters of higher alcohols, higher alcohol ethers, and waxes; antibacterial agents; preservatives; rust inhibitors; and hygroscopic agents.

[0084] Furthermore, the treatment agent of the present invention may contain one or more low molecular weight silicones. Examples of low molecular weight silicones include, for example, linear or cyclic silicones having 2 to 7 silicon atoms. Specific examples of low molecular weight silicones include octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, heptamethyloctyltrisiloxane, hexamethyldisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, and the like. These low molecular weight silicones may be substituted with groups represented by the general formula (2) above. These low molecular weight silicones may be included as trace components of the amino group-containing silicone (A) and / or the aryl group-containing silicone (B). The content of low molecular weight silicone in the treatment agent of the present invention is preferably 5 parts by weight or less per 100 parts by weight of silicone having an amino group (A) and silicone having an aryl group (B).

[0085] The carbon fiber precursor treatment agent of the present invention preferably contains an amino group-containing silicone (A), an aryl group-containing silicone (B), and an aliphatic (poly)oxyalkylene derivative (C1), and optionally an aromatic (poly)oxyalkylene derivative (C2), a Brønsted acid compound (D), and other components (E), which are dissolved, solubilized, emulsified, or dispersed in water. There are no particular limitations on the weight percentage of water and the weight percentage of non-volatile matter in the carbon fiber precursor treatment agent. For example, these can be appropriately determined considering factors such as transportation costs when transporting the carbon fiber precursor treatment agent of the present invention and handling characteristics due to emulsion viscosity. The weight percentage of water in the carbon fiber precursor treatment agent is preferably 0.1 to 99.9% by weight, more preferably 10 to 99.5% by weight, and particularly preferably 50 to 99% by weight. The weight percentage (concentration) of non-volatile matter in the carbon fiber precursor treatment agent is preferably 0.01 to 99.9% by weight, more preferably 0.5 to 90% by weight, and particularly preferably 1 to 50% by weight.

[0086] The carbon fiber precursor treatment agent of the present invention can be manufactured by mixing the components described above. The method for emulsifying and dispersing the components described above is not particularly limited, and known methods can be employed. Such methods include, for example, adding each component constituting the carbon fiber precursor treatment agent to warm water under stirring to emulsify and disperse, or mixing each component constituting the carbon fiber precursor treatment agent and gradually adding water while applying mechanical shear force using a homogenizer, homomixer, ball mill, etc. to perform phase inversion emulsification. Alternatively, a method may be used in which some components are emulsified and the remaining components are dissolved and dispersed.

[0087] The carbon fiber precursor treatment agent of the present invention can be suitably used as a treatment agent for carbon fiber precursors.

[0088] [Carbon fiber precursor, method for producing the same, and method for producing carbon fiber] The carbon fiber precursor of the present invention is obtained by applying the above-mentioned treatment agent for carbon fiber precursors to a raw material carbon fiber precursor and then spinning it into yarn. The method for producing the carbon fiber precursor of the present invention includes a spinning step of applying the above-mentioned treatment agent for carbon fiber precursors to a raw material carbon fiber precursor and then spinning it into yarn. The present invention provides a method for producing carbon fibers, comprising a flame-retardant treatment step for converting a carbon fiber precursor to which the above-mentioned carbon fiber precursor treatment agent has been applied into flame-retardant fibers, and a carbonization treatment step for further carbonizing the flame-retardant fibers. The flame-retardant treatment step described above is preferably a flame-retardant treatment step in which a carbon fiber precursor is converted into flame-retardant fibers in an oxidizing atmosphere at 200 to 300°C, and the carbonization treatment step is preferably a step in which the flame-retardant fibers are further carbonized in an inert atmosphere at 300 to 2000°C. According to the carbon fiber manufacturing method of the present invention, since the carbon fiber precursor treatment agent of the present invention is used, the bundling properties are improved, the disorder and unevenness of the fiber bundles are reduced, and high-quality carbon fibers can be manufactured.

[0089] The yarn-making process involves applying a treatment agent for carbon fiber precursors to the raw material carbon fiber precursor to produce the carbon fiber precursor, and preferably includes an adhesion treatment process and a stretching process. The adhesion treatment process involves applying a treatment agent for carbon fiber precursors to the raw carbon fiber precursor after spinning the carbon fiber precursor. In other words, the treatment agent for carbon fiber precursors is applied to the raw carbon fiber precursor in the adhesion treatment process. Furthermore, when the raw carbon fiber precursor is stretched immediately after spinning, the high-magnification stretching after the adhesion treatment process is specifically called the "stretching process." The stretching process may be a moist heat stretching method using high-temperature steam, or a dry heat stretching method using a hot roller. Preferably, the stretching magnification in the stretching process is 2 to 20 times the total stretching magnification of the raw carbon fiber precursor immediately after spinning.

[0090] The carbon fiber precursor is preferably composed of acrylic fibers mainly comprising polyacrylonitrile, which is obtained by copolymerizing at least 95 mol% or more of acrylonitrile with 5 mol% or less of a flame-retardant promoting component. As the flame-retardant promoting component, a vinyl group-containing compound copolymerizable with acrylonitrile can be suitably used. There are no particular limitations on the single fiber fineness of the carbon fiber precursor, but from a balance between performance and manufacturing cost, it is preferably 0.1 to 2.0 dtex. Similarly, there are no particular limitations on the number of single fibers constituting the fiber bundle of the carbon fiber precursor, but from a balance between performance and manufacturing cost, it is preferably 1,000 to 96,000.

[0091] The carbon fiber precursor treatment agent may be applied to the raw material carbon fiber precursor at any stage of the yarn production process, but it is preferable to apply it once before the drawing process. It can be applied at any stage before the drawing process, for example, immediately after spinning. Furthermore, it may be applied again at any stage after the drawing process, for example, immediately after the drawing process, at the winding stage, or immediately before the flame-retardant treatment process. As for the application method, it may be applied using a roller or the like, or by immersion, spraying, etc.

[0092] In the adhesion treatment process, the application rate of the carbon fiber precursor treatment agent is preferably 0.1 to 5% by weight, and more preferably 0.3 to 1.5% by weight, relative to the weight of the carbon fiber precursor, in order to balance the effects of preventing adhesion and fusion between fibers with preventing deterioration of the carbon fiber quality due to the tar-like substances of the treatment agent in the carbonization treatment process. The application rate of the carbon fiber precursor treatment agent referred to here is defined as the percentage of the weight of the non-volatile components to which the carbon fiber precursor treatment agent has adhered relative to the weight of the carbon fiber precursor.

[0093] The flame-retardant treatment process involves converting carbon fiber precursors, to which a treatment agent for carbon fiber precursors has been applied, into flame-retardant fibers in an oxidizing atmosphere, for example, at 200-300°C. The oxidizing atmosphere can usually be an air atmosphere. The temperature of the oxidizing atmosphere is preferably 230-280°C. In the flame-retardant treatment process, the carbon fiber precursors after the coating treatment are subjected to heat treatment for 20-100 minutes (preferably 30-60 minutes) while a tension of a stretch ratio of 0.90-1.10 (preferably 0.95-1.05) is applied. In this flame-retardant treatment, flame-retardant fibers with a flame-retardant structure are produced through intramolecular cyclization and oxygen addition to the ring.

[0094] The carbonization process involves further carbonizing the flame-resistant fibers in an inert atmosphere, for example, at 300 to 2000°C. In the carbonization process, it is preferable to first perform a preliminary carbonization process (first carbonization process) by heat-treating the flame-resistant fibers for several minutes in a firing furnace with a temperature gradient from 300°C to 800°C in an inert atmosphere such as nitrogen or argon, while applying a tension with a draw ratio of 0.95 to 1.15. Subsequently, in order to further advance carbonization and graphitization, a second carbonization process is performed by heat-treating the flame-resistant fibers for several minutes in an inert atmosphere such as nitrogen or argon, while applying a tension with a draw ratio of 0.95 to 1.05 compared to the first carbonization process, thereby carbonizing the flame-resistant fibers. Regarding the control of the heat treatment temperature in the second carbonization process, it is preferable to set the maximum temperature to 1000°C or higher (preferably 1000 to 2000°C) while applying a temperature gradient. This maximum temperature is appropriately selected and determined according to the required properties (tensile strength, modulus of elasticity, etc.) of the desired carbon fiber.

[0095] In the carbon fiber manufacturing method of the present invention, if carbon fibers with an even higher elastic modulus are desired, a graphitization treatment step can be performed following the carbonization treatment step. The graphitization treatment step is usually carried out at a temperature of 2000 to 3000°C in an inert atmosphere such as nitrogen or argon, while applying tension to the fibers obtained in the carbonization treatment step.

[0096] The carbon fibers obtained in this way can be surface-treated to enhance their adhesion strength to the matrix resin when used as a composite material, depending on the purpose. Gas-phase or liquid-phase treatment can be employed as the surface treatment method, and from a productivity standpoint, liquid-phase treatment using electrolytes such as acids and alkalis is preferred. Furthermore, various sizing agents with excellent compatibility with the matrix resin can be added to improve the processability and handling of the carbon fibers. [Examples]

[0097] The present invention will be specifically described below with reference to examples, but is not limited to the examples described herein. In the following examples, percentages (%) and parts refer to "weight percent" and "parts by weight" respectively, unless otherwise specified. Each characteristic value was measured based on the method described below.

[0098] <pH of a 1.0% by weight non-volatile content diluted solution> The pH of each treatment agent was measured at 25°C in an aqueous dispersion prepared by diluting it with deionized water to a non-volatile content of 1.0% by weight.

[0099] <Application rate of treatment agent> The carbon fiber precursor, after being treated with the treatment agent, was alkali-dissolved in potassium hydroxide / sodium butyrate, then dissolved in water and adjusted to pH 1 with hydrochloric acid. Sodium sulfite and ammonium molybdate were added to this mixture to induce color development, and the silicon content was determined by colorimetric determination of silica-molybdenum blue (wavelength 815 mμ). Using the silicon content determined here and the silicon content in the treatment agent determined in advance by the same method, the application rate (weight %) of the carbon fiber precursor treatment agent was calculated.

[0100] <Number of fibers in a carbon fiber bundle> Carbon fiber precursors were stored under the following two conditions to produce carbon fibers, and the number of fibers was measured using the method described below. Storage condition 1: Store at room temperature for 7 days. Storage condition 2: Store at room temperature for 12 months. Carbon fiber bundles were pulled out from the bobbin without tension, and any fuzz was collected until 50 fuzz fibers were collected. The length of the carbon fiber bundles pulled out until 50 fibers were collected was measured, and the number of fuzz fibers per unit length (fuzz fibers / m) was calculated from the measured length of the carbon fiber bundles as the number of fuzz fibers present on the surface of the carbon fiber bundles. ◎ and ○ were used as passing grades. ◎: The number of fibers is less than 3 per meter, indicating low fiber content and particularly good quality. ○: The number of fibers is 3 or more but less than 10 fibers per meter, indicating low fiber content and good quality. ×: The number of fibers is 10 or more per meter, indicating a high amount of fibers and poor quality.

[0101] <Carbon fiber strength> Carbon fibers were prepared using carbon fiber precursors stored under the following two conditions. The tensile properties of the single fibers were measured according to the test method specified in JIS-R-7606, and the average value of 10 measurements was taken as the carbon fiber strength (GPa). Storage condition 1: Store at room temperature for 7 days. Storage condition 2: Store at room temperature for 12 months. Furthermore, the retention rate of carbon fiber strength over time was calculated using the following formula. (Maintenance rate (%)) = (Strength of carbon fiber produced using carbon fiber precursor after 12 months of storage at room temperature) / (Strength of carbon fiber produced using carbon fiber precursor after 7 days of storage at room temperature) × 100

[0102] <Inhibition of Degradation of Carbon Fiber Precursors> In evaluating the fluffiness and carbon fiber strength of the carbon fiber bundles described above, the degradation suppression ability of the carbon fiber precursor was determined according to the following criteria. A pass was marked with ○, and a failing grade with ×. Acceptance criteria: The number of fluffs in the carbon fiber bundle must be 0 or higher under both storage condition 1 and storage condition 2, and the carbon fiber strength retention rate must be 95% or higher.

[0103] [Example 1] A silicone containing amino groups (A), a silicone containing aryl groups (B), and an aliphatic (poly)oxyalkylene derivative (C1) were mixed to achieve the non-volatile content composition of the treatment agent shown in Table 1. The mixture was heated to 60-80°C during emulsification, and water was gradually added while stirring with a stirring blade at a tip speed of 3 m / s to perform emulsification. The weight percentage of silicone A in the non-volatile content of the treatment agent was 75% by weight, the weight percentage of silicone containing aryl groups (B) was 5% by weight, and the weight percentage of aliphatic (poly)oxyalkylene derivative (C1) was 20% by weight. The prepared treatment agent was then further diluted with water to obtain a diluted solution with a non-volatile content concentration of 3.0% by weight. A precursor carbon fiber precursor was prepared by copolymerizing a diluted solution with 97 mol% acrylonitrile and 3 mol% itaconic acid. The carbon fiber precursor was then coated with a treatment agent so that the non-volatile content was 1.0% by weight, and the carbon fiber precursor was produced through a stretching process (steam stretching, stretching ratio 2.1 times) (single fiber fineness 0.8 dtex, 24,000 filaments). This carbon fiber precursor was flame-retardant treated in a flame-retardant furnace at 250°C for 60 minutes, and then converted into carbon fiber by firing in a carbonization furnace with a temperature gradient of 300 to 1400°C under a nitrogen atmosphere. The results of the evaluation of each characteristic value are shown in Table 1.

[0104] [Examples 2-42, Comparative Examples 1-11] The non-volatile content composition was changed as shown in Tables 1-4, and when adding Brønsted acid compound (D), the treatment agent was prepared by dissolving and dispersing it after emulsification. Otherwise, the treatment agent for carbon fiber precursors, carbon fiber precursors, and carbon fibers were prepared and evaluated in the same manner as in Example 1. The results of the evaluation of each characteristic value are shown in Tables 1-4. Note that Example 5 and 18 Use this as an example.

[0105] [Table 1]

[0106] [Table 2]

[0107] [Table 3]

[0108] [Table 4]

[0109] The details of the non-volatile content composition shown in Tables 1-4 are as follows. <Silicone containing amino groups (A)> Amino-modified silicone a1: kinematic viscosity at 25°C: 10000 mmHg 2 / s, amino equivalent: 3600 g / mol, side-chain diamine type Amino-modified silicone a2: kinematic viscosity at 25°C: 1500 mmHg 2 / s, amino equivalent: 3800 g / mol, side-chain diamine type Amino-modified silicone a3: kinematic viscosity at 25°C: 250 mmHg 2 / s, amino equivalent: 7600 g / mol, side-chain diamine type Amino-modified silicone a4: kinematic viscosity at 25°C: 1700 mmHg 2 / s, amino equivalent: 3800 g / mol, side-chain monoamine type Aminopolyether-modified silicone a5: kinematic viscosity at 25°C: 3300 mmHg 2 / s, amino equivalent: 1800 g / mol, side-chain aminopolyether type

[0110] <Silicone containing aryl groups (B)> Diphenyl silicone b1: kinematic viscosity at 25°C: 100 mmHg 2 / s (phenyl group:methyl group = 5:95 (molar ratio)) Diphenylsilicone b2: Kinematic viscosity at 25°C: 170 mmHg 2 / s (phenyl group:methyl group = 28:72 (molar ratio)) Diphenyl silicone b3: Kinematic viscosity at 25°C: 3000 mmHg 2 / s (phenyl group:methyl group = 5:95 (molar ratio)) Aalkyl-modified silicone b4: Kinematic viscosity at 25°C: 900 mmHg 2 / s

[0111] <Aliphatic (poly)oxyalkylene derivatives (C1)> Aliphatic (poly)oxyalkylene derivative c1-1: Secondary alkyl ether with 12 to 14 carbon atoms in an alkyl group to which 5 moles of oxyethylene groups have been added. Aliphatic (poly)oxyalkylene derivatives c1-2: Secondary alkyl ethers with 12-14 carbon atoms in an alkyl group to which 9 moles of oxyethylene groups have been added. Aliphatic (poly)oxyalkylene derivative c1-3: 10-mol ethylene oxide adduct of oleic acid

[0112] <Aromatic (poly)oxyalkylene derivatives (C2)> Aromatic (poly)oxyalkylene derivative c2-1: Bisphenol A ether with 10 moles of oxyethylene groups added. Aromatic (poly)oxyalkylene derivative c2-2: Bisphenol A ether with 17.5 moles of oxyethylene groups added. Aromatic (poly)oxyalkylene derivative c2-3: Esterification reaction product of 1 mole of bisphenol A with 2 moles of oxyethylene groups added and 2 moles of lauric acid.

[0113] <Brønsted acid compound (D)> Brønsted acid compound d1: Acetic acid Brønsted acid compound d2: phosphoric acid

[0114] <Silicone containing polyether groups> Silicone with polyether groups p1: kinematic viscosity at 25°C: 130 mmHg 2 / s, HLB:4, EO / PO=40 / 60, Side-chain polyether-modified silicone Silicone with polyether groups p2: kinematic viscosity at 25°C: 200 mmHg 2 / s, HLB:6, EO / PO=50 / 50, Side-chain polyether-modified silicone

[0115] As can be seen from Tables 1 to 4, the carbon fiber precursor treatment agents of Examples 1 to 42 contained a silicone having an amino group (A), a silicone having an aryl group (B), and an aliphatic (poly)oxyalkylene derivative (C1), and were able to suppress the deterioration of the carbon fiber precursor over time. On the other hand, the carbon fiber precursor treatment agents of Comparative Examples 1 to 7 were not the carbon fiber precursor treatment agents of the present invention, and therefore could not suppress the deterioration of the carbon fiber precursor when the carbon fiber precursor produced with the treatment agents was stored for a long period of time. The carbon fiber precursor treatment agents of Comparative Examples 8 to 11 had poor emulsification stability and did not adhere uniformly to the precursor, so the carbon fiber precursor could not be produced normally and could not be used as carbon fiber precursor treatment agents. [Industrial applicability]

[0116] The carbon fiber precursor treatment agent of the present invention is a treatment agent used in the production of the carbon fiber precursor treatment agent, and is useful for producing high-quality carbon fibers. The carbon fiber precursor treatment agent of the present invention has been treated with the treatment agent of the present invention and is useful for producing high-quality carbon fibers. High-quality carbon fibers can be obtained by the carbon fiber production method of the present invention.

Claims

1. A treatment agent for carbon fiber precursors containing an amino group-containing silicone (A), an aryl group-containing silicone (B) (excluding the amino group-containing silicone (A) and the polyether group-containing silicone), and an aliphatic (poly)oxyalkylene derivative (C1), The proportion of the aryl group-containing silicone (B) in the non-volatile components of the treatment agent is 60% by weight or less. The aryl group-containing silicone (B) includes at least one selected from methylphenyl silicone and diphenyl silicone. The silicone (B) having the aryl group includes the diphenyl silicone, The silicone having the polyether group is excluding the silicone having the amino group (A), A treatment agent for carbon fiber precursors, wherein the proportion of the silicone having polyether groups in the nonvolatile components of the treatment agent is 0 to 10% by weight.

2. The carbon fiber precursor treatment agent according to claim 1, wherein the weight ratio (B / A) of the aryl group-containing silicone (B) to the amino group-containing silicone (A) is 1 or less.

3. The carbon fiber precursor treatment agent according to claim 1 or 2, wherein the weight ratio (B / C1) of the aryl group-containing silicone (B) to the aliphatic (poly)oxyalkylene derivative (C1) is 9 or less.

4. A treatment agent for carbon fiber precursors according to claim 1 or 2, comprising an aromatic (poly)oxyalkylene derivative (C2).

5. The carbon fiber precursor treatment agent according to claim 4, wherein the derivative (C2) comprises an alkylene oxide adduct (C2-1) of an aromatic compound having a hydroxyl group, and the aromatic compound having a hydroxyl group is a compound having a bisphenol skeleton.

6. The carbon fiber precursor treatment agent according to claim 1 or 2, wherein the molar ratio of phenyl groups to methyl groups (phenyl groups:methyl groups) in the methylphenyl silicone and the diphenyl silicone is 1:99 to 90:

10.

7. The treatment agent for carbon fiber precursors according to claim 1 or 2, wherein the pH of the diluted solution containing 1.0% by weight of non-volatile content is 4 to 8.

8. A carbon fiber precursor obtained by attaching the carbon fiber precursor treatment agent described in claim 1 or 2 to a raw material carbon fiber precursor.

9. A method for producing carbon fibers, comprising: a flame-retardant treatment step of converting the carbon fiber precursor described in claim 8 into flame-retardant fibers; and a carbonization treatment step of further carbonizing the flame-retardant fibers.

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