JP2010024582A - Finishing agent for acrylic fiber for production of carbon fiber and method for producing carbon fiber by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic fiber finishing agent for carbon fiber production, capable of establishing compatibility between the weld-prevention of fibers and the stable operation in the production of carbon fiber and free from problems of environment hormones; and to provide a carbon fiber production method to use the agent. <P>SOLUTION: The acrylic fiber finishing agent for carbon fiber production essentially contains an ester compound having three of more ester groups in the molecule and a water-soluble amide compound. The carbon fiber production method includes an application treatment step to apply the acrylic fiber finishing agent for carbon fiber production to the acrylic fiber for carbon fiber production, a flame-proofing step to convert the treated acrylic fiber to a flameproof fiber in an oxidizing atmosphere at 200-300°C, and a carbonization step to carbonize the flameproof fiber by further heating in an inert atmosphere at 300-2,000°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an acrylic fiber oil agent for producing carbon fiber and a method for producing carbon fiber using the same. More specifically, when used for an acrylic fiber for carbon fiber production (hereinafter sometimes referred to as a precursor), an acrylic fiber oil for carbon fiber production (hereinafter referred to as a precursor oil may be obtained) that provides excellent processability. And a method for producing carbon fiber using the same.

Carbon fibers are widely used for aerospace applications, sports applications, general industrial applications and the like as reinforcing fibers for composite materials with plastics called matrix resins, utilizing their excellent mechanical properties.
As a method for producing carbon fiber, a method is generally used in which a precursor is converted to a flame-resistant fiber in an oxidizing atmosphere at 200 to 300 ° C., and subsequently carbonized in an inert atmosphere at 300 to 2000 ° C. At the time of firing by these high heats, there is a problem that fusion of single fibers occurs and the quality and quality of the obtained carbon fibers are deteriorated.

In order to prevent this fusion, silicone precursors with excellent heat resistance and excellent peelability due to smoothness between fibers and fibers, especially amino-modified silicone oils that can further improve heat resistance by crosslinking reaction, are given to precursors. Many techniques have been proposed (see Patent Documents 1 to 6) and are widely used industrially.
JP-A-6-220722 Japanese Patent Laid-Open No. 11-117128 JP 2001-172879 A JP 2002-371477 A JP 2003-201346 A Japanese Patent Laid-Open No. 2004-244771

However, on the other hand, the adhesion-treated silicone-based oil drops from the fiber to become an adhesive, which accumulates on a drying roller or a guide in the precursor manufacturing process, and the operability such as fiber sticking or breaking. There was a problem of causing a decrease. In addition, when silicon oxide is partly used in the oxidizing atmosphere of the flameproofing process and nitrogen is used as an inert gas in the inert atmosphere of the carbonizing process, silicon nitride is generated and these scales are deposited. However, there has been a problem that the operability and operability are deteriorated and the firing furnace is damaged.
Furthermore, the excellent releasability due to the smoothness between the fibers of the silicone-based oil agent works effectively for preventing fusion between single fibers, while in the firing process in which a large number of fiber bundles run in parallel at the same time. Has a disadvantage in that the width of each fiber bundle is expanded by the smoothness of the silicone-based oil agent, so that the interval between adjacent fiber bundles is narrowed, and in some cases, fluff is generated due to the interference.
In order to avoid these problems, an oil agent in which the content of the silicone compound is reduced, an oil agent that does not use the silicone compound, and the like have been proposed. For example, an oil agent in which a bisphenol A aromatic compound and an amino-modified silicone are combined (see Patent Documents 7 to 10), or an oil agent mainly composed of a fatty acid ester of an alkylene oxide adduct of bisphenol A (Patent Documents 11 and 12). See).

However, these oil agents are effective in suppressing the above-mentioned problems such as operability caused by silicone compounds, but bisphenols that are suspected of being endocrine disruptors (so-called environmental hormones) in the oil agent composition. There was a fault that it was inferior to the safety in use of containing A system compound.
JP 2000-199183 A JP 2002-266239 A JP 2004-211240 A JP 2005-89884 A Republished WO97-09474 pamphlet JP 2004-143645 A

  In view of such conventional technical background, the object of the present invention is to achieve both prevention of fusion between fibers and stable operability in the production of carbon fibers, and there is no doubt of environmental hormones. An object of the present invention is to provide an acrylic fiber oil and a method for producing carbon fiber using the same.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention are able to solve the above-mentioned problems at once if it is an acrylic fiber oil agent for producing carbon fibers containing a specific ester compound and a water-soluble amide compound as essential components. Obtaining the knowledge that it can be solved, the present invention has been reached.

That is, the acrylic fiber oil for producing carbon fibers according to the present invention is an acrylic fiber oil for producing carbon fibers containing an ester compound having three or more ester groups in the molecule and a water-soluble amide compound as essential components.
Moreover, in the acrylic fiber oil agent for producing carbon fibers according to the invention, it is preferable that the weight ratio of the silicone-based compound to the entire nonvolatile content of the oil agent is less than 10% by weight.

（式中、Ｒ^１、Ｒ^２およびＲ^３は、いずれも炭素数８〜２２の炭化水素基であり、同一であってもよく、異なっていてもよい。）

（式中、Ｒ^４、Ｒ^５、Ｒ^６およびＲ^７は、いずれも炭素数７〜２１の炭化水素基であり、同一であってもよく、異なっていてもよい。）

（式中、Ｒ^８、Ｒ^９およびＲ^１０は、いずれも炭素数７〜２１の炭化水素基であり、同一であってもよく、異なっていてもよい。） The ester compound is at least one compound selected from an ester compound represented by the following general formula (1), an ester compound represented by the following general formula (2), and a compound represented by the following general formula (3). Is preferred.

^(Wherein, R 1, ^{R 2} and ^{R 3} are both a hydrocarbon group having 8 to 22 carbon atoms, it may be the same or may be different.)

(In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ are all hydrocarbon groups having ^{7 to} 21 carbon atoms, and may be the same or different.)

(In the formula, R ⁸ , R ⁹ and R ¹⁰ are all hydrocarbon groups having 7 to 21 carbon atoms, and may be the same or different.)

  The water-soluble amide compound is selected from a compound obtained by cationizing an amide compound, a compound obtained by adding alkylene oxide to an amide compound, and a compound obtained by adding alkylene oxide to an amide compound and further cationizing the water-soluble amide compound. It is preferable that it is at least one kind. The amide compound is preferably a compound obtained by reacting a polyamine having two or more amino groups in the molecule with a fatty acid.

  The weight ratio of the ester compound in the whole nonvolatile content is preferably 10 to 95% by weight, and the weight percentage of the water-soluble amide compound in the whole nonvolatile content is preferably 3 to 65% by weight.

Moreover, it is preferable that the acrylic fiber oil agent for carbon fiber manufacture concerning this invention contains a polycarboxylic acid polyether compound further, and the weight ratio which occupies for the whole non volatile matter is 0.5 to 40 weight%. Further, an antioxidant is further contained, and the weight ratio of the whole nonvolatile content is preferably 0.1 to 10% by weight.
The acrylic fiber oil for carbon fiber production according to the present invention preferably has a weight reduction rate of less than 30% after heat treatment at 250 ° C. in air for 1 hour. Moreover, it is preferable that the acrylic fiber oil agent for carbon fiber manufacture concerning this invention becomes the emulsion disperse | distributed in water.

  Moreover, the carbon fiber manufacturing method according to the present invention includes an adhesion treatment step in which the carbon fiber production acrylic fiber oil agent is adhered to the carbon fiber production acrylic fiber, and the acrylic fiber after the adhesion treatment is oxidized at 200 to 300 ° C. It is a manufacturing method including a flameproofing treatment step for converting to a flameproofing fiber in an atmosphere, and a carbonization treatment step for carbonizing the flameproofing fiber in an inert atmosphere at 300 to 2000 ° C.

  The acrylic fiber oil agent for producing carbon fiber of the present invention can achieve both prevention of fusion between fibers and stable operability in carbon fiber production by performing a treatment for adhering this to a precursor in advance. Moreover, this acrylic fiber oil for producing carbon fibers is not suspected of being an environmental hormone. Moreover, in the carbon fiber manufacturing method of the present invention, since this acrylic fiber oil for carbon fiber manufacturing is adhered, high-quality carbon fibers can be manufactured.

The acrylic fiber oil for carbon fiber production (precursor oil) of the present invention is an oil intended to be applied to acrylic fiber (carbon fiber precursor) used for carbon fiber production, and has three or more esters in the molecule. An ester compound having a group and a water-soluble amide compound are contained as essential components. First, each component which comprises the acrylic fiber oil agent for carbon fiber manufacture is demonstrated.
[Ester compound]
In the precursor oil of the present invention, an ester compound having 3 or more ester groups in the molecule is an essential component of the oil composition. The ester compound is a component that enhances operability during firing while maintaining operability during yarn production in the production of carbon fibers. Due to its excellent heat resistance, this ester compound remains on the fiber during the flameproofing process together with the amide cationic compound described later, and prevents fusion between single fibers. In addition, high fiber-to-fiber friction improves the bundling property of the fiber bundle and realizes good operability during firing.

  The ester compound is not particularly limited as long as it is a compound having three or more ester groups in the molecule. For example, the ester compound has three or more ester groups in the molecule, and one ester group is carbon. -The ester compound etc. which have the structure connected with any other ester group only through the carbon bond can be mentioned. Such an ester compound is produced, for example, by dehydrating condensation of a polybasic acid and a higher alcohol or by dehydrating condensation of a polyhydric alcohol and a fatty acid.

Specific examples of the ester compound include an ester compound (1) represented by the general formula (1), an ester compound (2) represented by the general formula (2), and an ester compound represented by the general formula (3) ( 3), compounds in which six hydroxyl groups of dipentaerythritol are esterified. These ester compounds may be used alone or in combination of two or more.
Among the ester compounds, at least one compound selected from the ester compound (1), the ester compound (2) and the ester compound (3) has high heat resistance, and the flame resistance of the carbon fiber production method described later. In the crystallization treatment step, it is preferable because a remarkable effect can be obtained with respect to prevention of fusion between fibers and fibers and maintenance of fiber bundles.

The ester compound (1) can be produced by a known production method, for example, by dehydration condensation of trimellitic acid and a higher alcohol. R ^{1 to} R ³ in the ester compound (1) are all hydrocarbon groups having 8 to 22 carbon atoms (preferably having 8 to 18 carbon atoms, more preferably 10 to 13 carbon atoms), and are linear. It may have a side chain. Examples of R ^{1 to} R ³ include 2-ethylhexyl group, isodecyl group, lauryl group, isotridecyl group, stearyl group, isostearyl group, and oleyl group.
Specific examples of the ester compound (1) include tri-2-ethylhexyl trimellitate, triisodecyl trimellitate, triisotridecyl trimellitate and the like. These ester compounds (1) may be used alone or in combination of two or more.

The ester compound (2) can be produced by a known production method, for example, by dehydration condensation of pentaerythritol and a higher fatty acid. R ^{4 to} R ⁷ in the ester compound (2) are all hydrocarbon groups having 7 to 21 carbon atoms (preferably having 11 to 21 carbon atoms, more preferably 15 to 17 carbon atoms), and are linear. It may have a side chain. Moreover, all of R ^{4 to} R ⁷ may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of R ^{4 to} R ⁷ include a hydrocarbon group having a structure in which a carboxyl group is removed from a higher fatty acid such as caprylic acid, lauric acid, palmitic acid, stearic acid, isostearic acid, oleic acid, and behenic acid. it can. Among these R ⁴ to R ^7, in terms of heat resistance, stearic, isostearic, hydrocarbon group having a structure excluding a carboxyl group from the higher fatty acids such as oleic acid are preferable.
Specific examples of the ester compound (2) include pentaerythritol tetralaurate, pentaerythritol tetrastearate, pentaerythritol tetraisostearate, pentaerythritol tetraoleate and the like. These ester compounds (2) may be used alone or in combination of two or more.

The ester compound (3) can be produced by a known production method, for example, by dehydration condensation of trimethylolpropane and a higher fatty acid. R ^{8 to} R ¹⁰ in the ester compound (3) are all hydrocarbon groups having 7 to 21 carbon atoms (preferably having 11 to 21 carbon atoms, more preferably 15 to 17 carbon atoms), and are linear. It may have a side chain. Moreover, all of R ^{8 to} R ¹⁰ may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. As R < ⁸ > -R < ¹⁰ >, the hydrocarbon group illustrated as said R < ⁴ > -R < ⁷ > etc. can be mentioned as it is, for example, It is the same also about a preferable thing.
Specific examples of the ester compound (3) include trimethylolpropane trilaurate, trimethylolpropane tristearate, trimethylolpropane triisostearate, trimethylolpropane trioleate, and the like. These ester compounds (3) may be used alone or in combination of two or more.

[Water-soluble amide compound]
In the precursor oil agent of the present invention, the water-soluble amide compound is the second essential component. Since the water-soluble amide compound has excellent heat resistance and has a nitrogen atom in its structure, it has excellent affinity for the precursor, which is an acrylic fiber, and can form a uniform heat-resistant film on the fiber. . Furthermore, since the present compound itself is water-soluble, the ability to form a uniform film on the fiber is particularly high when the precursor oil of the present invention is applied to the precursor as a water emulsion. Therefore, it remains as a uniform film on the fiber together with the above-described ester compound in the flameproofing treatment process and the initial carbonization process, and effectively prevents fusion between single fibers. In addition, by containing a water-soluble amide compound as an essential component together with the ester compound, a film having an appropriate friction characteristic to obtain excellent operability during firing and anti-fusing property will be formed on the fiber, which will be described later. This silicone compound can be unnecessary or greatly reduced. In addition, problems such as operability caused by the silicone compound can be significantly suppressed.

  The water-soluble amide compound is not particularly limited as long as it is a water-soluble amide compound, but from the viewpoint of fiber-to-fiber smoothness and heat resistance, an amide compound is added to the amide compound and alkylene oxide is added to the amide compound. A compound obtained by adding an alkylene oxide to a compound or an amide compound and further cationizing it is preferable. One or two or more water-soluble amide compounds may be used in combination. These water-soluble amide compounds can be produced by a known production method.

  The amide compound is not particularly limited as long as it is a compound having an amide bond in the molecule, but has 2 or more (preferably 2 to 5, more preferably 2 to 3) amino groups in the molecule. A compound obtained by reacting a polyamine with a fatty acid is preferred. These amide compounds can be produced by a known production method. For example, an amide compound can be obtained at 140 to 170 ° C. to obtain an amide compound.

Examples of the polyamine include polyethylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, polypropylene polyamines such as propylenediamine, dipropylenediamine and tripropylenetetramine, and polybutylene polyamines such as butylenediamine and dibutylenetriamine. Among them, diethylenetriamine and triethylenetetramine are preferable from the viewpoints of smoothness between fibers and fibers and reduction in tarring residue after firing.
As said fatty acid, a C8-C30 fatty acid is preferable, a C12-C22 fatty acid is more preferable, and a C16-C18 fatty acid is further more preferable. When the number of carbon atoms is less than 8, the heat resistance of the compound may be reduced, and when the number of carbon atoms exceeds 30, the dispersibility of the compound in water may be deteriorated. Further, the fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and the hydrocarbon group obtained by removing a carboxyl group from the fatty acid may be linear or branched. Examples of the fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, isostearic acid, oleic acid, linoleic acid, linolenic acid and the like. Among these, palmitic acid and stearic acid are preferable.

The amide compound is not particularly limited as a cationized compound. For example, an amide compound at 100 to 130 ° C. according to a known method using a cationizing agent such as epichlorohydrin, trimethyl phosphate, triethoxy phosphate, dimethyl sulfate, diethyl sulfate or trimethyl chloride. A water-soluble amide compound can be obtained by performing a cationization reaction.
Although there is no limitation in particular as a compound which added the alkylene oxide to the amide compound, For example, according to a well-known method, it can obtain by adding an alkylene oxide. The alkylene oxide is preferably an alkylene oxide having 2 to 4 carbon atoms, and examples thereof include ethylene oxide, propylene oxide, butylene oxide, and among these, ethylene oxide is preferable. Two or more of these alkylene oxides can be used in combination, and the unit may be either random or block. 5-100 are preferable, as for the addition mole number of alkylene oxide, 10-30 are more preferable, and 10-20 are more preferable. If the number of added moles is less than 5, the water dispersibility may be lowered, and if it exceeds 100, the thermal stability and the affinity for fibers may be lowered.
A compound obtained by adding an alkylene oxide to an amide compound and further cationizing is not particularly limited. For example, according to a known method, an alkylene oxide exemplified above is added, and further according to a known method, the cation exemplified above. It can be obtained by cationization with an agent.

[Silicone compounds]
In the precursor oil of the present invention, the silicone compound can be reduced unnecessarily or significantly by containing the ester compound and the water-soluble amide compound as essential components. Silicone compounds may be contained within a range that does not impair the effects of the present invention, but in order to reliably suppress problems such as operability caused by the silicone compounds, silicones occupy the entire nonvolatile content of the precursor oil. It is preferable to reduce the weight ratio of the compound, for example, less than 10% by weight.
The silicone compound is not particularly limited as long as it is an organosilicon compound having a plurality of silicone bonds (—O—Si—O—) in the molecule. Dimethyl silicone; amino-modified silicone, epoxy-modified silicone, alkylene oxide-modified silicone, etc. And various modified silicones; and mixtures thereof.

[Polycarboxylic acid polyether compound]
The precursor oil agent of the present invention preferably further contains a polycarboxylic acid polyether compound. The polycarboxylic acid polyether compound acts as a compatibilizer for the ester compound and the water-soluble amide compound, which are the essential components described above, due to its excellent heat resistance and structure / characteristic properties. Due to the presence of the polycarboxylic polyether-based acid compound, the ester compound and the water-soluble amide-based compound form a heat-resistant film on the fiber surface more uniformly, and more effectively prevent the fusion of single fibers in the firing step.
The polycarboxylic acid polyether compound is not particularly limited as long as it is a compound synthesized from polycarboxylic acid and polyether. For example, dicarboxylic acid such as succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid or the like Examples thereof include condensates of anhydrides with polyalkylene glycols such as polyethylene glycol and polypropylene glycol, or alkyls and allyl ethers thereof.
Specific examples of the polycarboxylic acid compound include “Mariarim” (registered trademark) AKM-0531, “Mariarim” (registered trademark) AWS-0851, “Mariarim” (registered trademark) HKM- manufactured by NOF Corporation. 50A, “Mariarim” (registered trademark) AAB-0851, and the like.
These polycarboxylic acid polyether compounds may be used alone or in combination of two or more.

〔Antioxidant〕
The antioxidant is a component that effectively suppresses thermal decomposition of the precursor oil agent by heating in the flameproofing treatment step and enhances the effect of preventing fusion between fibers.
Although there is no limitation in particular as antioxidant, From a viewpoint of baking furnace contamination prevention, an organic antioxidant is preferable. Examples of organic antioxidants include phenolic antioxidants, amine antioxidants, sulfur antioxidants, phosphorus antioxidants, quinone antioxidants, and the like. For example, 4,4′-butylidenebis ( 3-methyl-6-tert-butylphenol, trioctadecyl phosphite, N, N′-diphenyl-p-phenylenediamine, triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) Propionate], dioleyl-thiodipropionate, etc. These organic antioxidants may be used alone or in combination of two or more.

[Surfactant]
The surfactant is used as an emulsifier, and is a component that emulsifies or disperses the precursor oil, and can improve the uniform adhesion to the fiber and the safety of the working environment.
The surfactant is not particularly limited, and a known one can be appropriately selected from nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants. Surfactant may use together 1 type (s) or 2 or more types.
Nonionic surfactants include, for example, alkylene oxide-added nonionic surfactants (higher alcohols, higher fatty acids, alkylphenols, styrenated phenols, benzylphenols, sorbitans, sorbitan esters, castor oil, hydrogenated castor oil, etc. And alkylene oxides such as oxides and propylene oxides (two or more types can be used together), polyalkylene glycols added with higher fatty acids, and ethylene oxide / propylene oxide copolymers. .
Examples of the anionic surfactant include carboxylic acid (salt), sulfate ester salt of higher alcohol / higher alcohol ether, sulfonate salt, phosphate ester salt of higher alcohol / higher alcohol ether, and the like.
Examples of cationic surfactants include quaternary ammonium salt type cationic surfactants (such as lauryltrimethylammonium chloride and oleylmethylethylammonium etosulphate), amine salt type cationic surfactants (polyoxyethylene laurylamine), and the like. Lactate etc.).
Examples of amphoteric surfactants include amino acid type amphoteric surfactants (such as sodium laurylaminopropionate), betaine type amphoteric surfactants (such as stearyl dimethyl betaine, lauryl dihydroxyethyl betaine), and the like.

[Precursor oil]
The precursor oil of the present invention is an oil containing the above ester compound and a water-soluble amide compound as essential components. In the precursor oil of the present invention, the content of the silicone compound is preferably small. Specifically, the weight ratio of the silicone compound in the whole nonvolatile content is preferably less than 10% by weight, more preferably 5% by weight or less, and more preferably 3% by weight. % Or less is more preferable, and 1% by weight or less is particularly preferable. When the weight ratio of the silicone compound in the entire nonvolatile content is 10% or more, there is operability and operability due to scale deposition in the flameproofing process and the carbonization process, which is not preferable. In the present invention, the non-volatile content means an absolutely dry component when the oil agent is heat treated at 105 ° C. to remove the solvent and the like and reach a constant weight.

  The weight ratio of the ester compound in the entire nonvolatile content of the precursor oil of the present invention is not particularly limited, but from the viewpoint of maintaining a balance between operability during firing and prevention of fusion between fibers and fibers in the production of carbon fibers. Is preferably 10 to 95% by weight, more preferably 20 to 80% by weight, further preferably 30 to 60% by weight, and particularly preferably 40 to 50% by weight. When the weight ratio of the ester compound exceeds 95% by weight, the weight ratio of the water-soluble amide compound, which is another essential component, is inevitably less than 5% by weight, and the fiber-fiber fusion prevention property is insufficient. It becomes. On the other hand, when the weight ratio of the ester compound is less than 10% by weight, the fiber bundle may not be sufficiently converged in the flameproofing treatment step, and good operability during firing may not be obtained.

  The weight ratio of the water-soluble amide compound in the entire nonvolatile content of the precursor oil agent of the present invention is not particularly limited, but the balance between the operability during firing and the prevention of fusion between fibers and fibers in the production of carbon fibers is maintained. From this viewpoint, 3 to 60% by weight is preferable, 5 to 50% by weight is more preferable, 10 to 40% by weight is further preferable, and 15 to 30% by weight is particularly preferable. If the weight ratio of the water-soluble amide compound is less than 3% by weight, the affinity of the oil agent to the precursor and the heat resistance will be insufficient, and the fiber-fiber fusion prevention property will be insufficient. On the other hand, when the weight ratio of the water-soluble amide compound exceeds 60% by weight, the operability at the time of firing is insufficient, and the tar-residue of the oil component after the precursor firing causes the fusion between the fibers. It may increase and the strength of the carbon fiber may decrease.

  The precursor oil of the present invention may further contain a polycarboxylic acid polyether compound, and the weight ratio of the polycarboxylic acid polyether compound in the entire nonvolatile content of the precursor oil is not particularly limited, but is an ester compound. From the viewpoint of the compatibilizing effect of the water-soluble amide compound and the operability during yarn production, 0.5 to 40% by weight is preferred, 1 to 30% by weight is more preferred, 1 to 10% by weight is still more preferred, 5% by weight is particularly preferred. When the weight ratio of the polycarboxylic acid polyether compound exceeds 40% by weight, an oily agent sticking substance may be deposited on a drying roller or the like in the spinning process, and the operability during spinning may be deteriorated.

  The precursor oil of the present invention may further contain an antioxidant, and the weight ratio of the antioxidant to the entire nonvolatile content of the precursor oil is not particularly limited. From the viewpoint of emulsification stability when an oil agent is used as an emulsion, 0.1 to 10% by weight is preferable, 0.5 to 5% by weight is more preferable, and 1 to 3% by weight is further preferable.

  The precursor oil of the present invention may further contain a surfactant. The weight ratio of the surfactant to the entire nonvolatile content of the precursor oil is not particularly limited, but from the viewpoint of maintaining the heat resistance of the oil and the emulsion stability when used as an emulsifier, it is 5 to 50 weight. % Is preferable, 10 to 40% by weight is more preferable, and 20 to 30% by weight is further preferable.

  In addition to the components described above, the precursor oil of the present invention further includes sulfate esters and sulfonates of higher alcohols and higher alcohol ethers, phosphate esters of higher alcohols and higher alcohol ethers, and quaternary ammonium salt type cationic surfactants. Antistatic agents; antiseptics; antiseptics; rust preventives; and hygroscopic agents, etc., antistatic agents such as agents, amine salt type cationic surfactants, smoothing agents such as higher alcohol alkyl esters, higher alcohol ethers, waxes It may be contained as long as the effects of the invention are not impaired.

Precursor oil may be composed of the above-mentioned components consisting only of non-volatile components, but from the viewpoint of uniform adhesion to fibers and safety in the working environment, it contains a surfactant as an emulsifier and is emulsified in water. Alternatively, it is preferable that the emulsion is dispersed and dispersed in water.
When the precursor oil agent of the present invention contains water, the weight ratio of water in the entire precursor oil agent, the weight ratio of the non-volatile content is not particularly limited, for example, transportation costs when transporting the precursor oil agent of the present invention, What is necessary is just to determine suitably considering the handleability etc. which depend on emulsion viscosity. The weight ratio of water in the entire precursor oil 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 ratio (concentration) of the non-volatile component in the entire precursor oil 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.

  The precursor oil of the present invention can be produced by mixing the components described above. In particular, when the precursor oil is a composition in the state of being emulsified or dispersed in water, the method for emulsifying and dispersing the components described above is not particularly limited, and a known method can be employed. As such a method, for example, each component constituting the precursor oil agent is put into warm water under stirring and emulsified and dispersed, and each component constituting the precursor oil agent is mixed, homogenizer, homomixer, ball mill, etc. A method of gradually injecting water and applying phase inversion emulsification while applying a mechanical shearing force using the above-mentioned method.

  The weight reduction rate of the precursor oil of the present invention is not particularly limited, but from the viewpoint of heat resistance in the flameproofing treatment process and the effect of preventing fusion between fibers and fibers, heat treatment at 250 ° C. in air for 1 hour. The subsequent weight loss rate is preferably less than 30%, and more preferably less than 25%. When the weight reduction rate is 30% or more, the oil agent film remaining on the fiber in the flameproofing treatment step decreases, and the effect of preventing fusion between the fibers and the fibers may not be sufficiently obtained.

Carbon fiber can be produced using the precursor oil agent of the present invention. Although the manufacturing method of carbon fiber using the precursor oil agent of this invention is not specifically limited, For example, the following manufacturing methods can be mentioned.
[Method for producing carbon fiber]
The carbon fiber manufacturing method of the present invention includes an adhesion treatment step, a flameproofing treatment step, and a carbonization treatment step.
The adhesion treatment step is a step in which an acrylic fiber for carbon fiber production (precursor) is produced and an acrylic fiber oil for carbon fiber production (precursor oil) is adhered to the obtained precursor. In the adhesion treatment step, the precursor oil agent is adhered to the precursor.
A precursor is comprised from the acrylic fiber which has as a main component the polyacrylonitrile obtained by copolymerizing at least 95 mol% or more of acrylonitrile and 5 mol% or less of a flame-resistant acceleration | stimulation component. As the flame resistance promoting component, a vinyl group-containing compound having copolymerizability with acrylonitrile can be suitably used. Although there is no limitation in particular about the single fiber fineness of a precursor, from the balance of a performance and manufacturing cost, Preferably it is 0.1-2.0 dTex. Further, the number of single fibers constituting the precursor fiber bundle is not particularly limited, but is preferably 1,000 to 96,000 from the balance between performance and production cost.
The precursor oil may be attached to the precursor at any stage of the adhesion treatment process. That is, the precursor oil agent may be attached immediately after spinning, may be attached after stretching, or may be attached at a subsequent winding stage. Regarding the adhesion method, when the precursor oil consists only of non-volatile components, it may be adhered using a roller or the like as a straight oil, or the precursor oil is emulsified or dispersed in a solvent such as water or an organic solvent. In the case of an emulsion, it may be attached by dipping or spraying.
In the adhesion treatment process, the application rate of the precursor oil agent is based on the balance between obtaining the effect of preventing fusion between fibers and fibers and preventing the deterioration of the quality of the carbon fiber by the tar product of the oil agent in the carbonization treatment step. The content is preferably 0.1 to 2% by weight, more preferably 0.3 to 1.5% by weight, based on the weight of the precursor. When the application rate of the precursor oil is less than 0.1% by weight, the fusion between the single fibers cannot be sufficiently prevented, and the strength of the obtained carbon fibers may be lowered. On the other hand, when the application rate of the precursor oil is more than 2% by weight, the precursor oil covers more than necessary between the single fibers, so that the supply of oxygen to the fibers is hindered in the flameproofing process, and the strength of the obtained carbon fiber May decrease. In addition, the provision rate of precursor oil agent here is defined with the percentage of the non volatile matter weight to which the precursor oil agent adhered with respect to the precursor weight.

  The flameproofing treatment step is a step of converting the acrylic fiber after the adhesion treatment (acrylic fiber to which the precursor oil is adhered) into flameproof fiber in an oxidizing atmosphere at 200 to 300 ° C. The oxidizing atmosphere is usually an air atmosphere. The temperature of the oxidizing atmosphere is preferably 230 to 280 ° C. In the flameproofing treatment step, the acrylic fiber after the adhesion treatment is applied for 20 to 100 minutes (preferably 30) while applying a tension ratio of 0.90 to 1.10 (preferably 0.95 to 1.05). Heat treatment is performed for ˜60 minutes. In this flameproofing treatment, a flameproof fiber having a flameproof structure is produced through intramolecular cyclization and oxygen addition to the ring.

  The carbonization treatment step is a step of carbonizing the flameproof fiber in an inert atmosphere of 300 to 2000 ° C. In the carbonization treatment step, first, in a firing furnace having a temperature gradient from 300 ° C. to 800 ° C. in an inert atmosphere such as nitrogen or argon, a tension ratio of 0.95 to 1.15 is applied to the flameproof fiber. It is preferable to carry out a pre-carbonization treatment step (first carbonization treatment step) by applying heat treatment for several minutes while applying. Thereafter, in order to further promote carbonization and advance graphitization, a tension ratio of 0.95 to 1.05 is applied to the first carbonization treatment step in an inert atmosphere such as nitrogen or argon. While being applied, heat treatment is performed for several minutes to perform the second carbonization treatment step, and the flame resistant fiber is carbonized. About control of the heat processing temperature in a 2nd carbonization process process, it is good to make maximum temperature into 1000 degreeC or more (preferably 1000-2000 degreeC), applying a temperature gradient. This maximum temperature is appropriately selected and determined according to the required characteristics (tensile strength, elastic modulus, etc.) of the desired carbon fiber.

In the carbon fiber manufacturing method of the present invention, when a carbon fiber having a higher elastic modulus is desired, the graphitization treatment step can be performed subsequent to the carbonization treatment step. The graphitization treatment step is usually performed at a temperature of 2000 to 3000 ° C. while applying tension to the fiber obtained in the carbonization treatment step in an inert atmosphere such as nitrogen or argon.
The carbon fiber thus obtained can be subjected to a surface treatment for increasing the adhesive strength with the matrix resin when made into a composite material, depending on the purpose. As the surface treatment method, gas phase or liquid phase treatment can be adopted, and from the viewpoint of productivity, liquid phase treatment with an electrolytic solution of acid, alkali or the like is preferable. Furthermore, various sizing agents having excellent compatibility with the matrix resin can be added to improve the processability and handleability of the carbon fiber.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, it is not limited to the Example described here. The percent (%) shown in the following examples represents “% by weight” unless otherwise specified. Each characteristic value was measured based on the following method.

<Grant ratio>
The application rate of the precursor oil after application of the oil was calculated by an ethanol extraction method using a Soxhlet extractor. However, for Examples 8 and 9 and Comparative Example 1 containing a silicone compound, the application rate was calculated by the following method.
The precursor after application of the oil was alkali-fused with potassium hydroxide / sodium butyrate, dissolved in water, and adjusted to pH 1 with hydrochloric acid. This was added with sodium sulfite and ammonium molybdate to develop a color, and colorimetric determination (wavelength 815 mμ) of silicomomolybdenum blue was performed to determine the silicon content. The application rate of the precursor oil was calculated using the silicon content obtained here and the value of the silicon content in the oil obtained in advance by the same method.

<Yarn operability (roller dirt)>
The degree of contamination (gum-up) of the drying roller after applying the oil to 50 kg of the precursor was determined according to the following evaluation criteria.
◎: There is no roller contamination due to gum up, and there is no problem with spinning operation ○: Little roller contamination due to gum up and there is no problem with spinning operation △: There is some roller contamination due to gum up, but there is no problem with spinning operation ×: Gum Roller contamination due to up, slightly inferior in yarn-manufacturability XX: Roller contamination due to gum-up is remarkable, single yarn is taken out during yarn production, and there is a string

<Operability during firing (convergence)>
In the precursor firing step, the passing state of the flameproof fiber bundle immediately after passing through the flameproofing furnace was determined according to the following evaluation criteria.
○: Good bundleability of the fiber bundle, good operability without interference with the adjacent fiber bundle, etc. ×: The fiber bundle width is slightly widened, and there is interference with the adjacent fiber bundle, and fluff may occur. is there.

<Fused prevention>
Twenty locations were selected at random from carbon fibers, 10 mm-long short fibers were cut out therefrom, the fused state was observed, and the following evaluation criteria were used.
◎: No fusion ○: Almost no fusion △: Less fusion ×: Many fusion

<Carbon fiber strength>
Measurement was performed according to the epoxy resin impregnated strand method defined in JIS-R-7601, and the average value of 10 measurements was defined as carbon fiber strength (GPa).

<Oil agent heat resistance (weight reduction rate)>
Each oil emulsion was collected on an aluminum cup having a diameter of 60 mm so that the weight of the nonvolatile content was 1 g, and treated with a hot air dryer at 105 ° C. for 3 hours to remove moisture. The obtained sample (1 g) was heat-treated in a gear oven at 250 ° C. for 1 hour. The percentage of the weight decreased after the heat treatment relative to the oil weight before the heat treatment was defined as the weight reduction rate (%). It shows that heat resistance is so high that the numerical value of a weight decreasing rate is low.

[Example 1]
A water-soluble amide system in which R ^{1 to} R ³ in the general formula (1) are cationized with epichlorohydrin from an ester compound M-1 having an isodecyl group (carbon number: 10), and an amide compound obtained by reacting diethylenetriamine and stearic acid. Compound N-1 was added to a nonionic surfactant (polyoxyethylene 7 mol addition alkyl ether (alkyl group having 12 to 14 carbon atoms), polyoxyethylene 12 mol addition tristyrenated phenyl ether, and ethylene oxide / propylene oxide (50 / 50) A water-based emulsification with a block copolymer), and an oil agent emulsion (precursor oil agent) having a weight ratio of M-1 / N-1 / nonionic surfactant = 35/25/40 as an oil agent non-volatile composition. Obtained. The oil agent non-volatile content concentration was 3.0% by weight.
This oil agent emulsion was attached to a precursor (single fiber fineness 0.8 dtex, 24,000 filaments) so as to give an application rate of 1.0%, and dried at 100 to 140 ° C. to remove moisture. The precursor after adhering the oil was flameproofed for 60 minutes in a 250 ° C flameproofing furnace, and then baked in a carbonization furnace having a temperature gradient of 300 to 1400 ° C in a nitrogen atmosphere to be converted into carbon fibers. Table 1 shows the evaluation results of the characteristic values.

[Examples 2 to 10 and Comparative Examples 1 to 3]
In Examples 2 to 10 and Comparative Examples 1 to 3, Example 1 is the same as Example 1 except that the oil agent emulsion was prepared so that the oil agent non-volatile composition (% by weight) shown in Tables 1 to 3 was obtained. Similarly, the precursor and carbon fiber after oil agent adhesion were obtained. The evaluation results of each characteristic value in each example and comparative example are also shown in Tables 1 to 3 as in Example 1.
As is apparent from Tables 1 to 3 below, in the examples as compared with the comparative examples, both good maneuverability during spinning and anti-fusing properties are compatible, and the carbon fiber strength is also silicone-based. The result comparable to the comparative example 1 using an oil agent was obtained.

M-1: An ester compound in which R ^{1 to} R ³ in General Formula (1) are an isodecyl group (carbon number: 10) M-2: R ^{1 to} R ³ in General Formula (1) are an isotridecyl group (carbon number: 13) ester compound N-1: water-soluble amide compound obtained by cationizing an amide compound obtained by reacting diethylenetriamine and stearic acid with epichlorohydrin N-2: amide obtained by reacting diethylenetriamine and behenic acid Water-soluble amide compound obtained by cationizing a compound with diethyl sulfuric acid N-3: Water-soluble amide compound obtained by adding 10 mol of ethylene oxide to an amide compound obtained by reacting diethylenetriamine and stearic acid N-4: diethylenetriamine and stearic acid To the amide compound obtained by reacting The Ren'okishido added 7 mol, a water-soluble amide-based and cationized by epichlorohydrin compound polycarboxylic acid polyether compound: "Malialim" (registered trademark) AKM-0531 (manufactured by NOF CORPORATION)
Nonionic surfactant: ethylene oxide 7 mol addition alkyl ether (alkyl group having 12 to 14 carbon atoms), ethylene oxide 12 mol addition tristyrenated phenyl ether, and ethylene oxide / propylene oxide (50/50) block copolymer Antioxidant: tri Ethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate]
PEG nonionic compound: 30 mol of ethylene oxide added bisphenol A ether Silicone compound: amino-modified silicone (25 ° C. viscosity: 1300 mm ² / s; amino equivalent: 2000 g / mol)

Claims (11)

  An acrylic fiber oil agent for carbon fiber production, containing an ester compound having three or more ester groups in the molecule and a water-soluble amide compound as essential components.   The acrylic fiber oil agent for carbon fiber manufacture of Claim 1 whose weight ratio of the silicone type compound to the whole non volatile matter of an oil agent is less than 10 weight%. The ester compound is at least one compound selected from an ester compound represented by the following general formula (1), an ester compound represented by the following general formula (2), and a compound represented by the following general formula (3). The acrylic fiber oil agent for carbon fiber manufacture according to claim 1 or 2.

(In the formula, R ¹ , R ² and R ³ are all hydrocarbon groups having 8 to 22 carbon atoms, and may be the same or different.)

(In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ are all hydrocarbon groups having ^{7 to} 21 carbon atoms, and may be the same or different.)

^(Wherein, R 8, ^{R 9} and ^{R 10} are both hydrocarbon group of 7 to 21 carbon atoms, it may be the same or may be different.)   The water-soluble amide compound is at least one selected from a compound obtained by cationizing an amide compound, a compound obtained by adding alkylene oxide to an amide compound, and a compound obtained by adding alkylene oxide to an amide compound and further cationized. Item 4. An acrylic fiber oil agent for producing carbon fiber according to any one of items 1 to 3.   The acrylic fiber oil for carbon fiber production according to claim 4, wherein the amide compound is a compound obtained by reacting a polyamine having two or more amino groups in the molecule with a fatty acid.   The weight ratio of the ester compound in the whole nonvolatile content is 10 to 95% by weight, and the weight percentage of the water-soluble amide compound in the whole nonvolatile content is 3 to 65% by weight. The acrylic fiber oil agent for carbon fiber manufacture of crab.   Furthermore, the acrylic fiber oil agent for carbon fiber manufacture in any one of Claims 1-6 which contains a polycarboxylic-acid polyether type compound and the weight ratio which occupies for the whole non volatile matter is 0.5 to 40 weight%.   Furthermore, the acrylic fiber oil agent for carbon fiber manufacture in any one of Claims 1-7 which contains antioxidant and the weight ratio to the whole non volatile matter is 0.1 to 10 weight%.   The acrylic fiber oil preparation for carbon fiber production according to any one of claims 1 to 8, wherein a weight reduction rate after heat treatment at 250 ° C in air for less than 30% is less than 30%.   The acrylic fiber oil preparation for carbon fiber production according to any one of claims 1 to 9, which is an emulsion dispersed in water.   An adhesion treatment step of attaching the acrylic fiber oil agent for producing carbon fiber according to any one of claims 1 to 10 to the acrylic fiber for carbon fiber production, and the acrylic fiber after the adhesion treatment in an oxidizing atmosphere at 200 to 300 ° C A method for producing carbon fiber, comprising: a flameproofing treatment step for converting to a flameproofing fiber; and a carbonization treatment step of carbonizing the flameproofed fiber in an inert atmosphere at 300 to 2000 ° C.