JP5712480B2 - Oil composition for carbon fiber precursor acrylic fiber, carbon fiber precursor acrylic fiber bundle and method for producing the same - Google Patents

Description

  The present invention relates to an oil composition for carbon fiber precursor acrylic fibers, a carbon fiber precursor acrylic fiber bundle, and a method for producing the same.

  Conventionally, as a method for producing a carbon fiber bundle, a carbon fiber precursor fiber bundle made of acrylic fiber or the like (hereinafter referred to as “precursor fiber bundle”) is heat-treated in an oxygen-existing atmosphere at 200 to 400 ° C. to make it flame resistant. There is known a method of obtaining a carbon fiber bundle by converting into a fiber bundle (flame-proofing process) and subsequently carbonizing under an inert atmosphere of 1000 ° C. or higher (carbonization process). Carbon fiber bundles obtained by this method are widely used industrially as reinforcing fibers for composite materials because of their excellent mechanical properties.

  However, in the process of manufacturing the carbon fiber bundle, fusion occurs between the single fibers in the flameproofing process, and the flameproofing process and the subsequent carbonization process (hereinafter referred to as the “firing process” In some cases, process failures such as fluff and bundle breakage may occur. As a method for preventing fusion between single fibers in the flameproofing process, a method of applying an oil agent composition to the surface of the precursor fiber bundle (oil agent treatment) is known, and many oil agent compositions have been studied. I came.

As the oil composition, a silicone-based oil mainly composed of silicone has been generally used so far.
However, the silicone oil has a high viscosity due to the progress of the crosslinking reaction by heating, and the adhesive is easily deposited on the surface of the fiber transport roller and guide used in the production process of the precursor fiber bundle and the flame resistance process. . For this reason, process failures such as the precursor fiber bundle and the flameproof fiber bundle being wound or caught by the fiber conveying roller or the guide are generated, and the operability may be lowered.
Moreover, the precursor fiber bundle to which the silicone-based oil agent was applied easily generated silicon compounds such as silicon oxide, silicon carbide, and silicon nitride in the firing step. When a silicon compound is produced, it leads to deterioration in operability and product quality.

Therefore, an oil composition having a reduced silicone content has been proposed for the purpose of reducing the silicon content of the precursor fiber bundle treated with the oil. For example, an oil agent composition containing 40 to 100% by mass of an emulsifier containing 50 to 100% by mass of a polycyclic aromatic compound to reduce the silicone content has been proposed (see Patent Document 1).
Further, an oil agent composition in which a heat-resisting resin having a residual ratio of 80% by mass or more after heating at 250 ° C. in air for 2 hours and silicone is proposed (see Patent Document 2).
Furthermore, an oil composition containing 10% by mass or more of a compound having a reactive functional group and not containing a silicone compound, or containing a silicone compound, in a range not exceeding 2% by mass in terms of silicon mass is proposed. (See Patent Document 3).

  In recent years, an oil composition comprising an ester compound having three or more ester groups in the molecule and a silicone compound as essential components has been proposed (see Patent Document 4). According to this oil agent composition, the silicone content can be reduced by the ester compound, and both fusion prevention between single fibers in carbon fiber production and stable operability can be achieved.

JP 2005-264384 A JP 2000-199183 A JP 2005-264361 A International Publication No. 07/0666517 Pamphlet

However, although the oil composition described in Patent Document 1 has a high emulsifier content, the stability of the emulsion is increased, but the bundle of precursor fibers to which this oil composition is adhered tends to have a low convergence and is high. It was not suitable for manufacturing with production efficiency. Furthermore, there is a problem that it is difficult to obtain a carbon fiber bundle excellent in mechanical properties.
The oil composition described in Patent Document 2 uses a bisphenol A-based aromatic ester as a heat-resistant resin, so the heat resistance is very high, but the effect of preventing fusion between single fibers is not sufficient. . Furthermore, there is a problem that it is difficult to stably obtain a carbon fiber bundle excellent in mechanical properties.
Furthermore, although the oil agent composition of patent document 3 can improve oil agent adhesiveness by raising the oil agent viscosity in 100-145 degreeC, since the viscosity is high, the precursor fiber bundle after an oil agent process is a fiber. Occasionally, process troubles such as wrapping around a conveyance roller or the like were caused, and operability was sometimes lowered.
In addition, when the oil agent composition described in Patent Document 4 is applied to the precursor fiber, the operability is stable, but the mechanical properties of the obtained carbon fiber bundle are higher than that of a silicone-based oil agent mainly composed of silicone. It was inferior.

As described above, the oil agent composition having a reduced silicone content may cause a decrease in operability. Moreover, compared with silicone type oil agent, there existed a tendency for the anti-fusing property, the convergence property of the precursor fiber bundle treated with the oil agent to deteriorate, and the mechanical properties of the carbon fiber bundle to be inferior. Therefore, it has been difficult to stably obtain a high-quality carbon fiber bundle.
On the other hand, in the case of silicone-based oils, there has been a problem of reduced operability due to higher viscosity and generation of silicon compounds.
In other words, the problem of operability deterioration due to the oil composition containing silicone as a main component, the anti-fusing property due to the oil composition having a reduced silicone content, the convergence property of the precursor fiber bundle, and the mechanical properties of the carbon fiber bundle. This problem is inextricably linked to each other, and the conventional technology cannot solve all the problems.

  The present invention has been made in view of the above circumstances, and effectively prevents fusion between single fibers in the production process of carbon fiber bundles, suppresses deterioration in operability, and has good convergence properties. It is another object of the present invention to provide a carbon fiber precursor acrylic fiber oil agent composition capable of obtaining a carbon fiber bundle excellent in mechanical properties, a carbon fiber precursor acrylic fiber bundle, and a method for producing the same.

  As a result of intensive studies, the inventors of the present invention used the trimellitic acid ester and / or pyromellitic acid ester in combination with a specific amino-modified silicone, and the problem of the above-described oil composition containing silicone as a main component, It has been found that the problem of the oil composition having a reduced silicone content can be solved together, and the present invention has been completed.

That is, the carbon fiber precursor acrylic fiber oil composition of the present invention has a kinematic viscosity at 25 ° C. of 50 to 300 mm ² / s, an amino equivalent of 1500 to 5000 g / mol, and an amino acid represented by the following formula (1). of the modified silicone 100 parts by weight, and the ester compound 100-350 weight parts of the following formula (2) and lower following formula (3), in that it contains a nonionic emulsifier 15-100 parts by weight Features.

  In formula (1), m is an arbitrary number of 1 or more.

In formula (2), R < ¹ > -R < ³ > is the same or different, and is a C8-C16 hydrocarbon group.

In formula (3), R ^{4 to} R ⁷ are the same or different and are hydrocarbon groups having 8 to 16 carbon atoms.

  Further, the nonionic emulsifier is preferably a block copolymer type polyether represented by the following formula (4) and / or a polyoxyethylene alkyl ether represented by the following formula (5).

In formula (4), R ^{8 to} R ⁹ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms, and x to z are the same or Differently, it is 1-500.

In Formula (5), R ¹⁰ is a hydrocarbon group having 10 to 20 carbon atoms, and n is 3 to 20.

Furthermore, the oil agent composition for a carbon fiber precursor acrylic fiber of the present invention preferably contains 1.5 to 5 parts by mass of an antioxidant with respect to 100 parts by mass of the amino-modified silicone.
Moreover, the carbon fiber precursor acrylic fiber bundle of the present invention is characterized in that 0.1 to 2% by mass of the oil agent composition for carbon fiber precursor acrylic fiber is attached to the dry fiber mass.
In the method for producing a carbon fiber precursor acrylic fiber bundle of the present invention, the carbon fiber precursor acrylic fiber oil composition is dispersed in water to form micelles having an average particle diameter of 0.01 to 0.5 μm. And a step of applying the aqueous emulsified solution to the precursor fiber bundle in the water-swelled state and a step of drying and densifying the precursor fiber bundle to which the aqueous emulsified solution is applied.

According to the present invention, it is possible to effectively prevent fusion between single fibers in the production process of carbon fiber bundles, suppress deterioration in operability, and have excellent precursor fiber bundles and good mechanical properties with good convergence. An oil agent composition for a carbon fiber precursor acrylic fiber capable of obtaining a carbon fiber bundle, a carbon fiber precursor acrylic fiber bundle, and a method for producing the same.
In addition, according to the present invention, it is possible to suppress a decrease in operability and the convergence property of the precursor fiber bundle is good. Therefore, the industrial productivity of the carbon fiber bundle is increased, and the high-quality carbon fiber bundle is stably formed. Can be obtained.

Hereinafter, the present invention will be described in detail.
[Oil agent composition for carbon fiber precursor acrylic fiber]
The oil agent composition for acrylic fibers for carbon fiber precursor of the present invention (hereinafter referred to as “oil agent composition”) contains an amino-modified silicone, an ester compound, and a nonionic emulsifier.

The amino-modified silicone is effective in improving the affinity and heat resistance of the oil agent composition with respect to a carbon fiber precursor acrylic fiber bundle (hereinafter also simply referred to as “precursor fiber bundle”) before the oil agent treatment described later.
Amino-modified silicones are kinematic viscosity of 50 to 300 mm ² / s at 25 ° C., is preferably 50 to 150 mm ² / s. When the kinematic viscosity is less than 50 mm ² / s, the heat resistance of the obtained oil agent composition is lowered, and it becomes difficult to sufficiently prevent fusion between single fibers in the flameproofing step. On the other hand, when the kinematic viscosity exceeds 300 mm ² / s, it becomes difficult to prepare an emulsion of the oil composition. In addition, the stability of the emulsion of the oil agent composition is lowered, and it becomes difficult to uniformly adhere to the precursor fiber bundle. As a result, it becomes difficult to sufficiently prevent the fusion between single fibers, or the bundle of precursor fiber bundles. May decrease. Furthermore, the fiber separation property in the flameproofing process is lowered, and particularly when large tow is produced, spots are generated between the single fibers, making it difficult to obtain a high-quality carbon fiber bundle.

  The kinematic viscosity of the amino-modified silicone is a value measured according to JIS-Z-8803 or ASTM D 445-46T, and can be measured using, for example, a Ubbelohde viscometer.

  The amino-modified silicone has an amino equivalent of 1500 to 5000 g / mol, preferably 1500 to 3000 g / mol. When the amino equivalent is less than 1500 g / mol, the number of amino groups in one silicone molecule is excessively increased, the thermal stability of the amino-modified silicone is lowered, and the process is hindered. On the other hand, when the amino equivalent exceeds 5000 g / mol, the number of amino groups in one silicone molecule becomes too small, the compatibility with the precursor fiber bundle becomes poor, and the oil agent composition becomes difficult to adhere uniformly. In some cases, it becomes difficult to sufficiently prevent the fusion of the precursor fibers, and the convergence of the precursor fiber bundle may be deteriorated.

The amino-modified silicone has a structure represented by the above formula (1).
In formula (1), m is an arbitrary number of 1 or more. Specifically, 10-300 is preferable and 10-150 is more preferable. When m is less than 10, the heat resistance of the oil composition is likely to decrease, and it becomes difficult to prevent fusion between single fibers in the flameproofing step. On the other hand, when m exceeds 300, the viscosity of the oil composition tends to rise transiently. As a result, the precursor fiber bundle to which the oil agent composition of the present invention is attached easily wraps around the fiber transport roller and the like, causing a process failure and easily reducing the operability.

In addition, m in Formula (1) can measure the kinematic viscosity of amino modified silicone, and can approximate it as an estimated value from this kinematic viscosity.
The procedure for determining m is to first measure the kinematic viscosity of the amino-modified silicone, and determine the A.M from the measured kinematic viscosity value. J. et al. The molecular weight is calculated according to the Barry equation (log η = 1.00 + 0.0123 M ^0.5 , (η: kinematic viscosity at 25 ° C., M: molecular weight)). The value of m that forms the structure of the amino-modified silicone can then be determined from this molecular weight.
Since m is an average value, it does not necessarily become an integer, but is displayed by rounding off the following as two significant figures.

  As such amino-modified silicone, commercially available products can be used, such as “x-22-161B”, “KF-8012” manufactured by Shin-Etsu Chemical Co., Ltd., “FM-3325” manufactured by Chisso Corporation, and the like. Is preferred.

The ester compound has a structure represented by the above formula (2) or the above formula (3).
In the formula (2), R ^{1 to} R ³ are the same or different and are each a hydrocarbon group having 8 to 16 carbon atoms. In the formula (3), R ^{4 to} R ⁷ are the same or different and each has a carbon number. 8 to 16 hydrocarbon groups.
In R ¹ to R ^7, when each of the number of carbon atoms is less than 8, and lowering the heat resistance of the oil composition, it is difficult to sufficiently prevent the fusion between single fibers in the oxidation step. On the other hand, when the number of carbons exceeds 16, it is difficult to prepare a uniform oil composition emulsion and it is difficult to uniformly adhere to the precursor fiber bundle, and as a result, it becomes difficult to sufficiently prevent fusion between fibers. Or the convergence of the precursor fiber bundle may decrease. Furthermore, the viscosity of the oil composition tends to increase, and the operability tends to decrease.

  The hydrocarbon group is preferably a saturated hydrocarbon group such as a saturated chain hydrocarbon group or a saturated cyclic hydrocarbon group. Specifically, an octyl group, a nonyl group, a decyl group, an undecyl group, a lauryl group (dodecyl group). , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group and the like.

As R ^{1 to} R ⁷ , a saturated hydrocarbon group having 8 to 14 carbon atoms is preferable in terms of easy preparation of an emulsion of a uniform oil agent composition, and 12 to 16 carbon atoms in terms of excellent heat resistance in the presence of water vapor. The saturated hydrocarbon group is preferable.

  Since the ester compound (trimellitic acid ester) represented by the above formula (2) and the ester compound (pyromellitic acid ester) represented by the above formula (3) are excellent in compatibility with the amino-modified silicone described above, The oil agent composition can be uniformly attached to the body fiber bundle. Furthermore, it is effective for the production of a precursor fiber bundle for obtaining a carbon fiber bundle having excellent mechanical properties.

The oil agent composition of the present invention contains trimellitic acid ester and / or pyromellitic acid ester.
Content of these ester compounds is 30-350 mass parts with respect to 100 mass parts of said amino modified silicone, and 100-350 mass parts is preferable. When the content of the ester compound is less than 30 parts by mass, the balance with the amino-modified silicone is lost, and the oil agent composition is difficult to uniformly adhere to the precursor fiber bundle. And the carbon fiber bundle obtained by baking the precursor fiber bundle to which the oil agent composition of this invention adheres becomes difficult to express the stable physical property. On the other hand, if the content of the ester compound exceeds 350 parts by mass, the proportion of the amino-modified silicone decreases, the convergence of the precursor fiber bundle to which the oil composition is adhered decreases, and the precursor fiber bundle is fired. The mechanical properties of the carbon fiber bundle obtained in this way tend to decrease.

  Various known substances can be used as the nonionic emulsifier. For example, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, aliphatic ethylene oxide adduct, polyhydric alcohol aliphatic ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, aliphatic amide Polyethylene glycol type nonionic surfactants such as ethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts; aliphatic esters of glycerol, aliphatics of pentaerythrol Polyhydric alcohol type non-ions such as esters, aliphatic esters of sorbitol, aliphatic esters of sorbitan, aliphatic esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines Surfactants and the like. These emulsifiers may be used alone or in combination of two or more.

The nonionic emulsifier is preferably a block copolymer polyether represented by the above formula (4) and / or a polyoxyethylene alkyl ether represented by the above formula (5).
The block copolymer type polyether represented by the above formula (4) is a block copolymer type polyether composed of a propylene oxide (PO) unit and an ethylene oxide (EO) unit.

In formula (4), R ^{8 to} R ⁹ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 24 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms. The alkyl group may be linear or branched.
R ^{8 to} R ⁹ are determined in consideration of the balance with EO, PO, and other components of the oil agent composition, preferably a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, More preferably, it is a hydrogen atom.

x and z represent the number of moles of EO added, and y represents the number of moles of PO added.
x to z are the same or different and are 1 to 500, preferably 20 to 300.
Moreover, it is preferable that ratio (x + z: y) of the sum of x and z and y is 90: 10-60: 40.

Further, the block copolymer type polyether preferably has a number average molecular weight of 3000 to 20000. When the molecular weight is within the above range, it is possible to have both thermal stability and dispersibility in water required for an oil composition.
Further, the block copolymer type polyether preferably has a kinematic viscosity at 100 ° C. of 300 to 15000 mm ² / s. If the kinematic viscosity is within the above range, the permeation of the oil composition to the inside of the fiber is prevented, and in the drying step after being applied to the precursor fiber bundle, the single fiber is fed to the conveying roller or the like due to the viscosity of the oil composition. Process failure such as wrapping around is less likely to occur.
The kinematic viscosity of the block copolymer type polyether can be measured in the same manner as the kinematic viscosity of the amino-modified silicone.

On the other hand, in formula (5), R ¹⁰ is a hydrocarbon group having 10 to 20 carbon atoms. When the number of carbon atoms is less than 10, the thermal stability of the oil composition is likely to be lowered, and appropriate lipophilicity is hardly exhibited. On the other hand, when the number of carbon atoms exceeds 20, the operability may deteriorate due to the viscosity of the oil composition becoming high or the oil composition becoming solid. In addition, the balance with the hydrophilic group is deteriorated, and the emulsification performance may be lowered.
The hydrocarbon group is preferably a saturated hydrocarbon group such as a saturated chain hydrocarbon group or a saturated cyclic hydrocarbon group, specifically a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, A hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, etc. are mentioned. Among these, in order to efficiently emulsify the oil agent composition, a dodecyl group is particularly preferable in terms of imparting an appropriate lipophilicity that is easily adapted to other oil agent composition components.

n shows the addition mole number of EO, is 3-20, 5-15 are preferable and 5-10 are more preferable. When n is less than 3, it is difficult to adjust to water and it becomes difficult to obtain emulsification performance. On the other hand, when n exceeds 20, the viscosity increases, and when used as a component of the oil composition, the fiber separation property of the precursor fiber bundle to which the obtained oil composition is attached tends to be lowered.
Here, R ¹⁰ is an element involved in the lipophilicity of the oil composition, and n is an element involved in the hydrophilicity of the oil composition. Therefore, the value of n is suitably determined by a combination of R ^10.

  Content of a nonionic emulsifier is 15-100 mass parts with respect to 100 mass parts of said amino modified silicone, and 15-50 mass parts is preferable. When the content of the nonionic emulsifier is less than 150 parts by mass, emulsification is difficult and the stability of the emulsion may be deteriorated. On the other hand, when the content of the nonionic emulsifier exceeds 100 parts by mass, the converging property of the precursor fiber bundle to which the oil agent composition is adhered decreases, and the carbon fiber bundle obtained by firing the precursor fiber bundle Mechanical properties are likely to deteriorate.

The oil agent composition of the present invention preferably contains an antioxidant.
Various known substances can be used as the antioxidant, and phenol-based and sulfur-based antioxidants are suitable.
Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-p-cresol, 4,4′-butylidenebis- (6-t-butyl-3-methylphenol), 2,2′- Methylene bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene bis- (4-ethyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-ethylphenol, 1, 1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene -3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methyl) Eniru) propionate], tris (3,5-di -t- butyl-4-hydroxybenzyl) isocyanurate.
Specific examples of the sulfur-based antioxidant include dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, and ditridecyl thiodipropionate.
These antioxidants may be used alone or in combination of two or more.

  Further, as the antioxidant, those acting on the amino-modified silicone described above are particularly preferable. Among them, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] Methane and triethylene glycol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate] are preferred.

  The content of the antioxidant is preferably 1.5 to 5 parts by mass and more preferably 1.5 to 3 parts by mass with respect to 100 parts by mass of the amino-modified silicone. When the content of the antioxidant is less than 1.5 parts by mass, it is difficult to sufficiently obtain the antioxidant effect. For this reason, the amino-modified silicone in the oil composition adhered to the precursor fiber bundle in the process of producing the precursor fiber bundle may be heated to a resin by a heat roller or the like. When the amino-modified silicone is converted into a resin, it is likely to be deposited on the surface of a roller or the like, and the precursor fiber bundle is wound around, causing a process failure and lowering the operability. On the other hand, when content of antioxidant exceeds 5 mass parts, antioxidant will become difficult to disperse | distribute uniformly in an oil agent composition.

Furthermore, the oil agent composition of the present invention is intended to improve operability or improve the stability and adhesion characteristics of the oil agent composition depending on the equipment and use environment for adhering to the precursor fiber bundle. Further, additives such as antistatic agents and antibacterial agents may be contained.
A known substance can be used as the antistatic agent. Antistatic agents are broadly classified into ionic types and nonionic types, and ionic types include anionic, cationic and amphoteric, and nonionic types include polyethylene glycol type and polyhydric alcohol type. From the viewpoint of antistatic, ionic type is preferable, among them aliphatic sulfonate, higher alcohol sulfate ester salt, higher alcohol ethylene oxide adduct sulfate ester, higher alcohol phosphate ester salt, higher alcohol ethylene oxide adduct sulfate phosphate ester salt, Quaternary ammonium salt type cationic surfactants, betaine type amphoteric surfactants, higher alcohol ethylene oxide adducts polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid esters and the like are preferably used.
These antistatic agents may be used alone or in combination of two or more.

A known substance can be used as the antibacterial agent. For example, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, Nn-butyl-1,2- Benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-methyl-4,5-trimethylene Isothiazoline-based compounds such as -4-isothiazolin-3-one; 2-bromo-2-nitropropane-1,3-diol, 2,2-dibromo-2-nitroethanol, 2,2-dibromo-3-nitrilopropion Organic bromine compounds such as amide, 1,2-dibromo-2,4-dicyanobutane, hexabromodimethylsulfone; formaldehyde, glutaral Aldehyde compounds such as hydride and o-phthalaldehyde; 3-methyl-4-isopropylphenol, 2-isopropyl-5-methylphenol, o-phenylphenol, 4-chloro-3,5-dimethylphenol, 2,4, Phenolic compounds such as 4′-trichloro-2′-hydroxydiphenyl ether and 4,4′-dichloro-2′-hydroxydiphenyl ether; 8-oxyquinoline, 2,3,5,6-tetrachloro-4- (methylsulfonyl) ) Pyridine compounds such as pyridine, bis (2-pyridylthio-1-oxide) zinc, (2-pyridylthio-1-oxide) sodium; N, N ′, N ″ -trishydroxyethylhexahydro-S-triazine, Triazines such as N, N ′, N ″ -trisethylhexahydro-S-triazine Compounds; Anilide compounds such as 3,4,4′-trichlorocarbanilide and 3-trifluoromethyl-4,4′-dichlorocarbanilide; Thiazoles such as 2- (4-thiocyanomethylthio) benzimidazole Compound; Imidazole compounds such as 2- (4-thiazolyl) -benzimidazole and methyl 2-benzimidazolecarbamate; 1-[[2- (2,4-dichlorophenyl) -4-n-propyl-1,3- Dioxolan-2-yl] methyl] -1H-1,2,4-triazole, (RS) -2- (2,4-dichlorophenyl) -1- (1H-1,2,4-triazol-1-yl) hexane -2-ol, α- [2- (4-chlorophenyl) ethyl] -α- (1,1-dimethylethyl) -1H-1,2,4-triazole-1 Ethanol, α- (chlorophenyl) -α- (1-cyclopropylethyl) -1H-1,2,4-triazole-1-ethanol, 1-[[2- (2,4-dichlorophenyl) -1,3- Triazole compounds such as dioxolan-2-yl] methyl-1H-1,2,4-triazole; 2,4,5,6-tetrachloroisophthalonitrile, 5-chloro-2,4,6-trifluoroisothiol Nitrile compounds such as talonitrile; Organochlorine compounds such as 4,5-dichloro-1,2-dithiolane-3-one and 3,3,4,4-tetrachlorotetrahydrothiophene-1,1-dioxide; 3 -Iodo-2-propynylbutyl carbamate, diiodomethyl-p-tolylsulfone, 2,3,3-triiodoallyl alcohol, etc. Thing, and the like. Of these, isothiazoline antibacterial agents are preferred.
These antibacterial agents may be used alone or in combination of two or more.

The oil agent composition of the present invention described above contains a specific amino-modified silicone, trimellitic acid ester and / or pyromellitic acid ester, and a nonionic emulsifier in a specific amount. It is possible to effectively prevent fusion between single fibers in the fiber bundle manufacturing process. Moreover, since generation | occurrence | production of a silicon compound can be reduced, process failure can be reduced and operativity fall can be suppressed. Furthermore, the carbon fiber precursor oil agent composition for acrylic fibers excellent in bundling property and the carbon fiber bundle excellent in mechanical properties can be obtained.
Thus, according to the oil agent composition of the present invention, it is possible to solve both of the problems of conventional oil agent compositions mainly composed of silicone and the problem of oil agent compositions having a reduced silicone content.

[Method for producing carbon fiber precursor acrylic fiber bundle]
In the method for producing the carbon fiber precursor acrylic fiber bundle of the present invention, the above-described amino-modified silicone, ester compound, nonionic emulsifier, and antioxidant, antistatic agent, and antibacterial agent are blended as necessary. A step of imparting the oil agent composition to the precursor fiber bundle in a water-swollen state (oil agent treatment) is performed, and then a step of drying and densifying the precursor fiber bundle treated with the oil agent is performed.
Hereinafter, each process in the manufacturing method of a carbon fiber precursor acrylic fiber bundle is demonstrated in detail.

(spinning)
As the precursor fiber bundle before the oil agent treatment used in the present invention, an acrylic fiber bundle spun by a known technique can be used. Specifically, an acrylic fiber bundle obtained by spinning an acrylonitrile polymer can be used.
The acrylonitrile-based polymer is a polymer obtained by polymerizing acrylonitrile as a main monomer. The acrylonitrile-based polymer may be a homopolymer obtained only from acrylonitrile, or may be an acrylonitrile-based copolymer in which other monomers are used in addition to the main component acrylonitrile.

  The content of acrylonitrile units in the acrylonitrile-based copolymer is 96 to 98.5% by mass to prevent heat fusion of fibers in the firing process, heat resistance of the copolymer, stability of the spinning dope, and carbon It is more preferable from the viewpoint of the quality of the fiber. When the acrylonitrile unit is 96% by mass or more, it is preferable because excellent quality and performance of the carbon fiber can be maintained without inducing the thermal fusion of the fiber in the firing step when converting to the carbon fiber. In addition, the heat resistance of the copolymer itself is not lowered, and adhesion between single fibers can be avoided in spinning the precursor fiber or in a process such as fiber drying or drawing with a heating roller or pressurized steam. On the other hand, when the acrylonitrile unit is 98.5% by mass or less, the solubility in the solvent is not lowered, the stability of the spinning stock solution can be maintained, and the precipitation solidification property of the copolymer is not increased. This is preferable because stable production of body fibers is possible.

As a monomer other than acrylonitrile in the case of using a copolymer, it can be appropriately selected from vinyl monomers copolymerizable with acrylonitrile, and acrylic acid or methacrylic acid having an action of promoting flameproofing reaction. , Itaconic acid, or an alkali metal salt or ammonium salt thereof, or a monomer such as acrylamide is preferable because flame resistance can be promoted.
As the vinyl monomer copolymerizable with acrylonitrile, carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid and itaconic acid are more preferable. The content of the carboxyl group-containing vinyl monomer unit in the acrylonitrile copolymer is preferably 0.5 to 2% by mass.
These vinyl monomers may be used alone or in combination of two or more.

  At the time of spinning, the acrylonitrile polymer is dissolved in a solvent to form a spinning dope. The solvent used here can be appropriately selected from known solvents such as organic solvents such as dimethylacetamide, dimethylsulfoxide, dimethylformamide, and aqueous inorganic compounds such as zinc chloride and sodium thiocyanate. Among these, dimethylacetamide, dimethylsulfoxide and dimethylformamide having a high coagulation rate are preferable from the viewpoint of improving productivity, and dimethylacetamide is more preferable.

In order to obtain a dense coagulated yarn, it is preferable to adjust the spinning dope so that the polymer concentration of the spinning dope becomes a certain level or more. Specifically, the polymer concentration in the spinning dope is preferably adjusted to 17% by mass or more, more preferably 19% by mass or more.
Since the spinning dope requires proper viscosity and fluidity, the polymer concentration is preferably within a range not exceeding 25% by mass.

  Spinning methods are known, such as a wet spinning method in which the above-mentioned spinning solution is directly spun into a coagulation bath, a dry spinning method in which the solution is coagulated in the air, and a dry and wet spinning method in which the solution is once coagulated in the air and then coagulated in the bath. A spinning method can be appropriately employed, but a wet spinning method or a dry-wet spinning method is preferable for obtaining a carbon fiber bundle having higher performance.

The spinning shaping by the wet spinning method or the dry and wet spinning method can be performed by spinning the spinning solution into a coagulation bath from a nozzle having a hole having a circular cross section. As the coagulation bath, it is preferable to use an aqueous solution containing a solvent used in the spinning dope from the viewpoint of easy solvent recovery.
When an aqueous solution containing a solvent is used as the coagulation bath, the solvent concentration in the aqueous solution is such that there is no void and a dense structure can be formed to obtain a high-performance carbon fiber bundle, and stretchability can be ensured and productivity is excellent. From 50 to 85 mass%, the temperature of the coagulation bath is preferably 10 to 60 ° C.

(Extension process)
A coagulated yarn obtained by dissolving a polymer or copolymer in a solvent and discharging into a coagulation bath as a spinning dope into a fiber can be stretched in a coagulation bath or in a stretching bath. . Alternatively, it may be partially stretched in the air and then stretched in a bath, and the precursor fiber bundle in a water-swelled state can be obtained by washing with water before or after stretching or simultaneously with stretching.
Stretching in the bath is usually carried out in a water bath at 50 to 98 ° C. by dividing it into multiple stages once or twice, and the coagulated yarn so that the total ratio of in-air stretching and stretching in the bath becomes 2 to 10 times. It is preferable from the viewpoint of the performance of the obtained carbon fiber bundle.

(Oil treatment)
For the application of the oil agent composition to the carbon fiber bundle, an aqueous emulsion solution (emulsion) in which the oil agent composition of the present invention is dispersed in water to form micelles having an average particle diameter of 0.01 to 0.5 μm is used. Use.
If the average particle diameter of the micelle is within the above range, the oil agent composition can be uniformly applied to the surface of the precursor fiber bundle.
In addition, the average particle diameter of the micelle in the water-based emulsified solution can be measured using a laser diffraction / scattering particle size distribution measuring device (trade name: LA-910, manufactured by Horiba, Ltd.).

The aqueous emulsified solution can be prepared, for example, as follows. That is, stirring an amino-modified silicone and a nonionic emulsifier, an ester compound is added and dispersed therein, and water is further added to obtain an aqueous emulsion solution in which the oil composition is dispersed in water.
When the antioxidant is contained, it is preferable to dissolve the antioxidant in amino-modified silicone in advance. When an antistatic agent and / or an antibacterial agent is contained, it is preferable to add and agitate after adding water to obtain an aqueous emulsion solution.
Each component can be mixed or dispersed in water using a propeller, a homomixer, a homogenizer or the like. In particular, it is preferable to use an ultrahigh pressure homogenizer that can pressurize to 150 MPa or more.

  2-40 mass% is preferable, as for the density | concentration of the oil agent composition in a water-system emulsified solution, 10-30 mass% is more preferable, and 20-30 mass% is especially preferable. When the concentration of the oil agent composition is less than 2% by mass, it is difficult to apply a necessary amount of the oil agent composition to the precursor fiber bundle in the water-swelled state. On the other hand, when the concentration of the oil composition exceeds 40% by mass, the aqueous emulsified solution becomes unstable and the emulsion is easily broken.

When applying the oil agent composition of the present invention to a precursor fiber bundle in a water-swollen state, it is preferable to add ion-exchanged water to the aqueous emulsified solution and dilute it to a predetermined concentration.
The “predetermined concentration” is adjusted according to the state of the precursor fiber bundle during the oil agent treatment. Hereinafter, the dispersion having a predetermined concentration is referred to as “oil treatment liquid”.

Application of the oil composition to the acrylic fiber bundle can be performed by applying an aqueous emulsion solution of the oil composition to the precursor fiber bundle in a water-swollen state after stretching in the bath.
When washing is performed after stretching in the bath, an aqueous emulsified solution of the oil composition can also be applied to the fiber swollen fiber bundle obtained after stretching and washing in the bath.

As a method for imparting the oil agent composition to the precursor fiber bundle in a water-swelled state, an oil agent treatment liquid is prepared by adding ion-exchanged water to a water-based emulsified solution in which the oil agent composition is dispersed in water and diluting to a predetermined concentration. Thereafter, a technique of attaching the precursor fiber bundle in a water-swollen state can be used.
As a method of attaching the oil treatment liquid to the precursor fiber bundle in the water-swelled state, the lower part of the roller is immersed in the oil treatment liquid, and the precursor fiber bundle is brought into contact with the upper part of the roller. The guide adhesion method in which the oil agent treatment liquid is discharged from the guide and the precursor fiber bundle is brought into contact with the guide surface, the spray adhesion method in which a predetermined amount of the oil agent treatment liquid is sprayed onto the precursor fiber bundle from the nozzle, and the oil agent treatment liquid A known method such as a dip attachment method in which the precursor fiber bundle is dipped in and then squeezed with a roller or the like to remove the excess oil agent treatment liquid can be used.
Among these methods, from the viewpoint of uniform adhesion, the dip adhesion method in which the oil agent treatment liquid is sufficiently infiltrated into the precursor fiber bundle and the excess treatment liquid is removed is preferable. In order to adhere more uniformly, it is also effective to apply the oil agent application step in two or more stages and repeatedly apply it.

(Drying densification process)
The precursor fiber bundle to which the aqueous emulsified solution is applied is dried and densified in the subsequent drying step.
The temperature for drying and densification needs to be performed at a temperature exceeding the glass transition temperature of the fiber, but may be substantially different depending on the dry state from the water-containing state. For example, it is preferable to perform dense drying by a method using a heating roller having a temperature of about 100 to 200 ° C. At this time, the number of heating rollers may be one or plural.

(Secondary stretching process)
The densely dried precursor fiber bundle is preferably subjected to stretching treatment with a heating roller. By the stretching treatment, the denseness and orientation degree of the obtained carbon fiber precursor acrylic fiber bundle can be further increased. In particular, the density of the carbon fiber precursor acrylic fiber bundle obtained by stretching by 1.1 to 4 times by changing the roller speed while conveying the densely dried precursor fiber bundle with a heating roller, The degree of orientation can be further improved.
The temperature of the heating roller is preferably about 150 to 200 ° C. If the temperature is lower than 150 ° C., plasticization becomes incomplete, fluff or the like occurs when stretched, fiber bundles are wound in the subsequent carbonization process, and process failure may be caused due to process failure. is there. On the other hand, when temperature exceeds 200 degreeC, an oxidation reaction, a decomposition reaction, etc. are started and the quality of the carbon fiber bundle obtained by baking a carbon fiber precursor acrylic fiber bundle may be reduced.

The carbon fiber precursor acrylic fiber bundle obtained through the drying densification treatment and the secondary stretching treatment with a heating roller is passed through a roller at room temperature, cooled to room temperature, and then wound around a bobbin with a winder or transferred to a can. Rarely stored.
And a carbon fiber precursor acrylic fiber bundle is moved to a baking process, and becomes a carbon fiber bundle.

[Carbon fiber precursor acrylic fiber bundle]
In the carbon fiber precursor acrylic fiber bundle of the present invention thus obtained, the oil agent composition of the present invention is preferably attached in an amount of 0.1 to 2% by mass, more preferably 0.00%. It is 5-1.5 mass%. When the adhesion amount of the oil composition is less than 0.1% by mass, it may be difficult to sufficiently exhibit the original function of the oil composition. On the other hand, when the adhesion amount of the oil agent composition exceeds 2% by mass, the excessively adhered oil agent composition may be polymerized in the firing step, which may cause adhesion between single fibers.
The “dry mass” refers to the dry fiber mass of the precursor fiber bundle after the dry densification treatment.

The adhesion amount of the oil composition is determined as follows.
In accordance with the Soxhlet extraction method using methyl ethyl ketone, the oil agent composition is extracted by immersing the carbon fiber precursor acrylic fiber bundle in 90 ° C. methyl ethyl ketone for 8 hours, and the mass W ₁ of the carbon fiber precursor acrylic fiber bundle before extraction, and after extraction of the mass W ₂ of the carbon fiber precursor acrylic fiber bundle were measured to determine the amount of adhered oil agent composition by the following formula (i).
Adhesion amount (mass%) of oil agent composition = (W ₁ −W ₂ ) / W ₂ × 100 (i)

As described above, since the method for producing a carbon fiber precursor acrylic fiber bundle of the present invention uses the oil composition of the present invention, a carbon fiber precursor acrylic fiber bundle excellent in convergence can be produced with high productivity.
In addition, the carbon fiber precursor acrylic fiber bundle of the present invention is excellent in convergence because the oil agent composition of the present invention is uniformly attached. Furthermore, since fusion between single fibers can be prevented in the firing process, and generation of silicon compounds and scattering of silicone decomposition products can be suppressed, the operability and process passability are significantly improved.
In addition, the carbon fiber bundle obtained by firing the carbon fiber precursor acrylic fiber bundle of the present invention is excellent in mechanical properties, high quality, and reinforced fiber used in fiber reinforced resin composite materials used in various structural materials. It is suitable as.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
Each component used in this example, various measurement methods, and evaluation methods are as follows.

[component]
<Amino-modified silicone>
A-1: Amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 55 mm ² / s and an amino equivalent of 1500 g / mol (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-22-161B).
A-2: Amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 90 mm ² / s and an amino equivalent of 2200 g / mol (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-8012).
A-3: Amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 300 mm ² / s and an amino equivalent of 5000 g / mol (manufactured by Chisso Corporation, trade name: FM-3325).
A-4: Amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 12 mm ² / s and an amino equivalent of 430 g / mol (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-8010).
A-5: Amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 450 mm ² / s and an amino equivalent of 5700 g / mol (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-8008).

<Ester compound; trimellitic acid ester>
B-1: Trimellitic acid ester in which R ^{1 to} R ³ are octyl groups having 8 carbon atoms in the above formula (2).
B-2: Trimellitic acid ester in which R ^{1 to} R ³ are a dodecyl group having 12 carbon atoms in the above formula (2).
B-3: Trimellitic acid ester in which R ^{1 to} R ³ in the formula (2) are hexadecyl groups having 16 carbon atoms.
B-4: Trimellitic acid ester in which R ^{1 to} R ³ in the above formula (2) are a stearyl group (octadecyl group) having 18 carbon atoms.
B-5: Trimellitic acid ester in which R ^{1 to} R ³ are an eicosyl group having 20 carbon atoms in the above formula (2).

<Ester compound; pyromellitic acid ester>
-C-1: The pyromellitic acid ester whose R < ⁴ > -R < ⁷ > is a C8 octyl group in said formula (3).
C-2: A pyromellitic acid ester in which R ^{4 to} R ⁷ are a dodecyl group having 12 carbon atoms in the above formula (3).
-C-3: The pyromellitic acid ester whose R < ⁴ > -R < ⁷ > is a C16 hexadecyl group in said formula (3).
-C-4: The pyromellitic acid ester whose R < ⁴ > -R < ⁷ > is a C18 stearyl group (octadecyl group) in the said Formula (3).
-C-5: The pyromellitic acid ester whose R < ⁴ > -R < ⁷ > is a C20 eicosyl group in the said Formula (3).

<Nonionic emulsifier>
D-1: In the above formula (4), R ^{8 to} R ⁹ are hydrogen atoms, x = 80, y = 30, z = 80, the number average molecular weight is 8000, and the kinematic viscosity at 100 ° C. is 400 mm ² / s. A block copolymer polyether composed of propylene oxide (PO) and ethylene oxide (EO) units (trade name: New Pole PE-68, manufactured by Sanyo Chemical Industries, Ltd.).
D-2: Polyoxyethylene lauryl ether in which R ¹⁰ is a dodecyl group having 12 carbon atoms and n = 9 in the above formula (5) (Nikko Chemicals, trade name: NIKKOL BL-9EX).

<Antioxidant>
A mixture of tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane and ditridecylthiodipropionate (mass ratio = 1: 2).

[Measurement / Evaluation]
<Measurement of oil adhesion amount>
After drying the carbon fiber precursor acrylic fiber bundle at 105 ° C. for 1 hour, the oil composition adhered by soaking in 90 ° C. methyl ethyl ketone for 8 hours was extracted with a solvent in accordance with a Soxhlet extraction method using methyl ethyl ketone. The mass W ₁ of the carbon fiber precursor acrylic fiber bundle before extraction and the mass W ₂ of the carbon fiber precursor acrylic fiber bundle after extraction were measured, respectively, and the adhesion amount of the oil composition was determined by the above formula (i). .

<Evaluation of convergence>
Observe the condition of the carbon fiber precursor acrylic fiber bundle on the final roller in the manufacturing process of the carbon fiber precursor acrylic fiber bundle, i.e., the roller immediately before winding the fiber bundle on the bobbin. The convergence was evaluated.
○: Converged, constant tow width, and not in contact with adjacent fiber bundle.
Δ: Converged, but tow width is not constant or tow width is wide.
X: There is a space in the fiber bundle and it is not focused.

<Evaluation of operability>
When the carbon fiber precursor acrylic fiber bundle was continuously produced for 24 hours, the operability was evaluated based on the frequency with which the single fiber was wound around and removed from the transport roller. The evaluation criteria were as follows.
○: The number of removals (times / 24 hours) is 1 or less.
Δ: 1 <removal frequency (times / 24 hours) 2 to 5 times.
X: The number of removal (times / 24 hours) is 6 times or more.

<Measurement of the number of fusions between single fibers>
A carbon fiber bundle is cut to a length of 3 mm, dispersed in acetone, stirred for 10 minutes, and the total number of single fibers and the number of single fibers fused together (number of fusions) are calculated. The number of fusions per 100 pieces was calculated and evaluated according to the following evaluation criteria.
○: The number of fusions (pieces / 100 pieces) is 1 or less.
X: The number of fusions (pieces / 100 pieces) is more than one.

<Measurement of strand strength>
Start production of carbon fiber bundles, sample carbon fiber bundles in a steady state, and measure strand strength of carbon fiber bundles according to the epoxy resin impregnated strand method specified in JIS-R-7608 did. The number of measurements was 10 times, and the average value was used as an evaluation target.

<Evaluation of quality stability>
After measuring the previous strand strength, firing was continuously performed for 10 days, a carbon fiber bundle was sampled once / day, and the strand strength was measured in the same manner as described above. The coefficient of variation of the total average value (for 10 days) of the strand strength of each day was calculated, and the degree of variation was used as an index of quality stability. Evaluation criteria were classified into the following three stages.
○: The coefficient of variation is less than 3%.
Δ: The coefficient of variation is 3% or more and 5% or less.
X: The coefficient of variation exceeds 5%.

<Measurement of Si scattering amount>
The amount of silicon-derived silicon compound scattered in the flameproofing process is calculated by using a fluorescent X-ray analyzer (made by Rigaku Denki Kogyo Co., Ltd.) Product name: measured with ZSX100e), the amount of Si scattered in the flameproofing process was calculated from the difference between them, and used as an evaluation index.
Specifically, as a measurement sample, using a carbon fiber precursor acrylic fiber bundle or a flameproof fiber bundle uniformly wound around an acrylic resin plate having a length of 20 mm, a width of 40 mm, and a width of 5 mm without any gaps, This was set in a fluorescent X-ray analyzer. At this time, it is important that the winding length of the fiber bundle attached to the measurement is the same. Thereafter, the fluorescent X-ray intensity of Si in each fiber bundle was measured by a normal fluorescent X-ray analysis method, and the Si content of each fiber bundle was determined using a calibration curve. The number of measurements was n = 10, the average value was calculated, and the amount of Si scattering was determined by the following formula (ii).
Si scattering amount (mg / kg) = Si content of carbon fiber precursor acrylic fiber bundle−Si content of flameproof fiber bundle (ii)

[Example 1]
<Preparation of oil agent composition>
Block copolymer polyether and polyoxyethylene lauryl ether as nonionic emulsifier are mixed and stirred in amino-modified silicone in which antioxidant is dispersed in advance, and trimellitic acid ester and pyromellitic acid ester are added as ester compounds there. In addition, ion-exchanged water was further added so that the concentration of the oil composition was 30% by mass and emulsified with a homomixer. The average particle size of the micelles in this state was measured using a laser diffraction / scattering type particle size distribution measuring device (trade name: LA-910, manufactured by Horiba, Ltd.), and was about 2 μm.
Then, it further disperse | distributed until the average particle diameter of the micelle became 0.2 micrometer or less with the high voltage | pressure homogenizer, and obtained the water-system emulsified solution (emulsion) of the oil agent composition.
Table 1 shows the types and blending amounts of each component in the oil composition (amounts of each component (parts by mass) relative to 100 parts by mass of amino-modified silicone).

<Manufacture of carbon fiber precursor acrylic fiber bundle>
A precursor fiber bundle to which the oil agent composition was adhered was prepared by the following method. Acrylonitrile copolymer (composition ratio: acrylonitrile / acrylamide / methacrylic acid = 96/3/1 (mass ratio)) is dissolved in dimethylacetamide, a spinning stock solution is prepared, and the pore size is set in a coagulation bath filled with a dimethylacetamide aqueous solution. (Diameter) 60 μm, the number of holes was 60000, discharged from a spinning nozzle to obtain a coagulated yarn. The coagulated yarn was desolvated in a washing tank and stretched 5 times to obtain a precursor fiber bundle in a water-swelled state.
In the oil treatment tank filled with the oil treatment liquid prepared by diluting the aqueous emulsion solution of the oil composition obtained above with ultrapure water and adjusting the concentration of the oil composition to 1.5% by mass, A swollen precursor fiber bundle was guided to give an aqueous emulsion solution.
Thereafter, the precursor fiber bundle to which the aqueous emulsified solution is applied is dried and densified with a roller having a surface temperature of 180 ° C., and then stretched twice using a roller having a surface temperature of 190 ° C. to obtain a carbon fiber precursor acrylic fiber bundle. It was.
The oil agent adhesion amount of the obtained carbon fiber precursor acrylic fiber bundle was measured, and the bundling property was evaluated. The results are shown in Table 1.

<Manufacture of carbon fiber bundles>
The obtained carbon fiber precursor acrylic fiber bundle was passed through a flame-proofing furnace having a temperature gradient of 220 to 260 ° C. to make the flame-resistant fiber bundle. Subsequently, the flame-resistant fiber bundle was baked in a carbonization furnace having a temperature gradient of 400 to 1300 ° C. in a nitrogen atmosphere to obtain a carbon fiber bundle.
The number of fusions between single fibers of the obtained carbon fiber bundle, the strand strength, and the amount of Si scattering in the flameproofing process were measured. The results are shown in Table 1.

[Examples 2 to 4, 6 and Reference Examples 5, 7 to 9]
An oil agent composition was prepared in the same manner as in Example 1 except that the types and blending amounts of each component constituting the oil agent composition were changed as shown in Table 1, and a carbon fiber precursor acrylic fiber bundle and a carbon fiber bundle were prepared. Was manufactured, and each measurement and evaluation was performed. The results are shown in Table 1.

[Comparative Examples 1 to 7]
An oil agent composition was prepared in the same manner as in Example 1 except that the types and blending amounts of each component constituting the oil agent composition were changed as shown in Table 2, and a carbon fiber precursor acrylic fiber bundle and a carbon fiber bundle were prepared. Was manufactured, and each measurement and evaluation was performed. The results are shown in Table 2.

As is clear from Table 1, in the case of each example, the amount of oil agent adhered was an appropriate amount. Moreover, the bundling property of the carbon fiber precursor acrylic fiber bundle and the operability in the production process were good.
In addition, Example 1 using the amino-modified silicone having a kinematic viscosity of 55 mm ² / s and an amino equivalent of 1500 g / mol, and the total content of the ester compound is 345 parts by mass with respect to 100 parts by mass of the amino-modified silicone. The carbon fiber precursor acrylic fiber bundle obtained in a certain example 4 has a tendency to be slightly inferior in convergence compared to other examples, and the operability in the example 4 also tends to be inferior to other examples. However, this was not a problem in the production process of the carbon fiber bundle.

In addition, the carbon fiber bundles obtained in each example had substantially no number of fusions between single fibers, showed a high strand strength, and were excellent in mechanical properties. Moreover, it was confirmed that the value of the variation coefficient of the strand strength is small, and high mechanical properties can be stably expressed even in continuous production. Furthermore, the amount of Si scattering in the firing process was small, and operability was good.
In addition, in Reference Examples 5 and 9, in which the total amount of other components is as small as 67.7 parts by mass and 67 parts by mass with respect to 100 parts by mass of the amino-modified silicone, the silicon compound is contained in the firing step as compared with the other examples. Although it was scattered a lot, it was not a problem level.
Moreover, the strand strength of the carbon fiber bundle showed a difference depending on the type and amount of components of the oil composition. Specifically, an amino-modified silicone having a kinematic viscosity of 90 mm ² / s and an amino equivalent of 2200 g / mol, and trimellitic acid ester in which R ^{1 to} R ³ are a dodecyl group having 12 carbon atoms in the above formula (2) And pyromellitic acid ester in which R ^{4 to} R ⁷ are a dodecyl group having 12 carbon atoms in the above formula (3), and the total content of the amino-modified silicone and the ester compound is the same, or amino-modified When the silicone content was high and the total ester compound content was low (Example 2, Reference Example 5), the strand strength of the carbon fiber bundle was particularly high. On the other hand, when the total content of the ester compound is large (Example 4), the strand strength of the carbon fiber bundle was lower than that of the other examples, but sufficient strength to be used as the reinforcing fiber of the composite material. Had. In Example 6, the total content of the ester compound was large, but the balance between the distribution of the amino-modified silicone and the ester compound and the content of the nonionic emulsifier for dispersing them was good, and the carbon fiber bundle was relatively high. The strand strength was shown.

Furthermore, the evaluation of quality stability (that is, the coefficient of variation in strand strength) in each example was different depending on the types of ingredients of the oil composition and the balance of the blending. Specifically, the amino-modified silicone is an amino-modified silicone having a kinematic viscosity of 90 mm ² / s and an amino equivalent of 2200 g / mol, or an amino-modified silicone having a kinematic viscosity of 300 mm ² / s and an amino equivalent of 5000 g / mol. And trimellitic acid ester in which R ^{1 to} R ³ are a dodecyl group having 12 carbon atoms or a hexadecyl group having 16 carbon atoms in the above formula (2) as an ester compound, and R ^{4 to} R ⁷ in the above formula (3). In combination with pyromellitic acid ester having 12 carbon atoms in dodecyl group or 16 carbon atoms in hexadecyl group, trimellitic acid ester and pyromellitic acid ester are each 50 parts by mass or 67 parts by mass with respect to 100 parts by mass of amino-modified silicone. In Examples 2, 3 and 6, which are more stable than the other examples It had an expression of strand strength.

On the other hand, as is clear from Table 2, in the case of Comparative Example 1 in which the total content of the ester compound is as large as 400 parts by mass with respect to 100 parts by mass of the amino-modified silicone, the oil agent adhesion amount is an appropriate amount. Although the amount of Si scattering was small and good, the convergence property of the obtained carbon fiber precursor acrylic fiber bundle and the operability in the production process were remarkably inferior to those of the examples. Moreover, the carbon fiber bundle has a large number of fusions between single fibers, and it has been difficult to industrially continuously produce the carbon fiber bundle. Furthermore, the strand strength was extremely low, and the coefficient of variation was large, so that the strand strength could not be expressed stably and the quality stability was poor.
In the case of Comparative Example 2 in which the total content of the ester compound is as small as 14 parts by mass with respect to 100 parts by mass of the amino-modified silicone, the obtained carbon fiber bundle showed a strand strength comparable to each example. The amount of Si scattering in the firing process was extremely large. Furthermore, although the strand strength was better than the other comparative examples, the value was not obtained stably, the fluctuation in the continuous production process was large, and the quality stability was inferior.
In the case of Comparative Example 3 using an amino-modified silicone having a kinematic viscosity of 12 mm ² / s and an amino equivalent of 430 g / mol, the convergence of the carbon fiber precursor acrylic fiber bundle and the operability in the production process are shown in each example. It was remarkably inferior to. Moreover, the carbon fiber bundle has a large number of fusions between single fibers, and it has been difficult to industrially continuously produce the carbon fiber bundle. Furthermore, compared with Example 2, the amount of Si scattering was large.

In the case of Comparative Example 4 using an amino-modified silicone having a kinematic viscosity of 450 mm ² / s and an amino equivalent of 5700 g / mol, when the precursor fiber bundle to which the aqueous emulsified solution is applied is densely dried, on the roller A fiber bundle was taken by the viscosity of the deposited silicone, and a process failure occurred in which the fiber bundle was wound around the roller. Further, the obtained carbon fiber bundle was fused between the single fibers.
Comparative Example 5 using trimellitic acid ester or pyromellitic acid ester in which R ^{1 to} R ⁷ in the above formulas (2) and (3) are stearyl groups having 18 carbon atoms as the ester compound, and the above formula (2) In the case of Comparative Example 6 using trimellitic acid ester or pyromellitic acid ester in which R ^{1 to} R ⁷ in (3) are an eicosyl group having 20 carbon atoms, the convergence property of the carbon fiber precursor acrylic fiber bundle is slightly inferior. It was. In addition, since the viscosity of the oil agent composition increased, the operability in the production of the carbon fiber precursor acrylic fiber bundle was significantly reduced. Therefore, it was difficult to operate continuously industrially. Furthermore, the coefficient of variation of the strand strength was large, the quality stability was poor, and a stable product could not be obtained.
In the case of Comparative Example 7 in which the content of the nonionic emulsifier is as large as 110 parts by mass with respect to 100 parts by mass of the amino-modified silicone, the convergence of the carbon fiber precursor acrylic fiber bundle and the operability in the production process are implemented. It was significantly inferior to the examples. Further, the obtained carbon fiber bundle was fused between the single fibers.

The oil composition for carbon fiber precursor acrylic fibers of the present invention can effectively suppress fusion between single fibers in the firing step. Furthermore, the carbon fiber precursor acrylic fiber bundle which can suppress the operativity fall which generate | occur | produces when using the oil agent composition which has silicone as a main component, and has favorable convergence can be obtained. A carbon fiber bundle excellent in mechanical properties can be produced from the carbon fiber precursor acrylic fiber bundle.
The carbon fiber bundle obtained from the carbon fiber precursor acrylic fiber bundle of the present invention can be formed into a composite material after prepreg. In addition, the composite material using the carbon fiber bundle can be suitably used for sports applications such as golf shafts and fishing rods, and as a structural material for automobiles, aerospace applications, and various gas storage tank applications. .

Claims (5)

25 kinematic viscosity at ℃ is 50 to 300 mm ² / s, amino equivalent weight of 1500~5000g / mol, relative to 100 parts by weight Amino-modified silicone represented by the following formula (1), the following equation (2) and containing the ester compound 100-350 parts by weight indicated below following formula (3), and a non-ionic emulsifier 15 to 100 parts by weight, the carbon fiber precursor acrylic fibers for oil composition.

(In formula (1), m is an arbitrary number of 1 or more.)

(In Formula (2), R < ¹ > -R < ³ > is the same or different, respectively, and is a C8-C16 hydrocarbon group.)

(In formula (3), R ^{4 to} R ⁷ are the same or different and are hydrocarbon groups having 8 to 16 carbon atoms.) The carbon fiber according to claim 1, wherein the nonionic emulsifier is a block copolymer polyether represented by the following formula (4) and / or a polyoxyethylene alkyl ether represented by the following formula (5). Oil agent composition for precursor acrylic fiber.

(In the formula ^(4), R 8 ~R ⁹ are the same or different and each is a hydrogen atom, an alkyl group or a cycloalkyl group having 3 to 12 carbon atoms, having 1 to 24 carbon atoms, each of x~z same Or, differently, 1 to 500.)

(In the formula ^{(5), R 10} is a hydrocarbon group having 10 to 20 carbon atoms, n represents 3 to 20.)   The oil composition for carbon fiber precursor acrylic fibers according to claim 1 or 2, comprising 1.5 to 5 parts by mass of an antioxidant with respect to 100 parts by mass of the amino-modified silicone.   The carbon fiber precursor acrylic fiber bundle which 0.1-2 mass% of oil agent compositions for carbon fiber precursor acrylic fibers in any one of Claims 1-3 adhered to dry fiber mass. It is a manufacturing method of the carbon fiber precursor acrylic fiber bundle according to claim 4,
The process of providing the aqueous | water-based emulsified solution which dispersed the said oil agent composition for carbon fiber precursor acrylic fibers in water, and formed the micelle of average particle diameter 0.01-0.5 micrometer to the precursor fiber bundle of a water swelling state When,
And a step of drying and densifying the precursor fiber bundle to which the aqueous emulsified solution is applied.