JP5017211B2 - Oil composition for carbon fiber precursor acrylic fiber, carbon fiber precursor acrylic fiber bundle using the same, and method for producing the same - Google Patents

Description

  The present invention is a flameproofing process in which a carbon fiber precursor acrylic fiber bundle (hereinafter also simply referred to as a precursor fiber bundle) is converted into a flameproof fiber bundle in the production process of carbon fiber, and fusion between single fibers is performed. The present invention relates to an oil agent composition for a carbon fiber precursor acrylic fiber (hereinafter also simply referred to as an oil agent composition) used for the purpose of preventing the occurrence. In addition, the present invention relates to a carbon fiber precursor acrylic fiber bundle provided with the oil composition and a method for producing the same.

  Since carbon fiber has higher specific strength and specific modulus than other fibers, it can be used as a reinforcing fiber for composite materials in addition to conventional sports and aerospace applications, as well as automobiles, civil engineering, architecture, pressure vessels, and windmills. Widely deployed in general industrial applications such as blades. Furthermore, there is a high demand for higher strength and higher elastic modulus in sports and aerospace applications that have been used conventionally.

  Among the carbon fibers, the most widely used method for producing a polyacrylonitrile-based carbon fiber bundle is to convert the acrylic fiber bundle into a flame-resistant fiber bundle by heat-treating in an oxygen-containing atmosphere at 200 to 400 ° C. Subsequently, a method for obtaining a carbon fiber bundle by carbonizing under an inert atmosphere of 1000 ° C. or higher is known. 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 method for producing a carbon fiber bundle, in the flameproofing process in which the precursor fiber bundle is mainly converted into a flameproofed fiber bundle, fusion occurs between single fibers, and the flameproofing process and the subsequent carbonization process (hereinafter referred to as the carbonization process) In some cases, the flameproofing process and the carbonization process are collectively referred to as a firing process), and process failures such as fluff and bundle breakage may occur. In order to avoid this fusion, it is known that selection of the oil agent to be attached to the acrylic fiber bundle is important, and many oil agent compositions have been studied.

  Furthermore, in order to meet the above-mentioned demands for high-performance carbon fiber in sports, aerospace, and space applications as described above, it is common to set a high tension or a high draw ratio in each manufacturing process. However, at this time, fusion between single fibers is likely to occur, and in order to produce stably, it is necessary to operate at a compromise draw ratio.

  Conventionally, many techniques for applying a silicone oil agent having high heat resistance to an acrylonitrile-based precursor fiber bundle have been proposed and widely applied industrially. For example, it is disclosed that an oil agent mixed with a specific amino-modified silicone, epoxy-modified silicone, and alkylene oxide-modified silicone has a low weight loss during heating in air and nitrogen and has a high anti-fusing effect (for example, Patent Document 1). However, these modified silicone fluids are used in the process of drying the precursor fiber bundle in the spinning process, where the fiber is taken up by the viscosity of the modified silicone oil on the heating roll, or a crosslinking reaction occurs due to the temperature, resulting in a resin. There was an obstacle. Further, in the flameproofing process, the supply of oxygen essential for the flameproofing reaction is hindered by intervening between the single fibers, and as a result, the occurrence of unevenness in the progress of the flameproofing reaction, so-called firing unevenness, is induced, and this is the cause. Thus, there is a problem that in the subsequent carbonization process, problems such as yarn breakage and fluff generation are likely to occur, which often becomes a major obstacle to productivity improvement.

  A technique for improving the above problem by specifying the curing behavior of the silicone oil has been disclosed (for example, Patent Document 2). However, with this technique, silicone acts like an adhesive by constraining single fibers to each other and sometimes causes uneven firing, so there is a limit to firing at a high draw ratio. Furthermore, there existed a problem that the hardened silicone oil agent accumulated on each guide or a groove-shaped roll in a baking process, and the fiber bundle wound.

  Moreover, the technique which provides a clearance gap between single fibers by using the particle | grains which consist of an organic compound and a silicone compound, and suppresses fusion between single fibers is disclosed (for example, patent document 3). However, fine particles fall off and contaminate the manufacturing process, and there are generation of fuzz due to the rubbing of the contaminants and fibers, and generation of scratches due to the fine particles being strongly pressed against the fibers, and there is a limit to firing at a high draw ratio. It was.

Furthermore, in recent years, the oil agent containing liquid fine particles whose essential component is a liquid having a kinematic viscosity at 150 ° C. of 15000 cSt or more suppresses fusion between single fibers in the production process of the precursor fiber bundle, and in the subsequent flame resistance process. Since it becomes possible to disperse single fibers without damaging the carbon fiber precursor, oxygen is uniformly supplied between the single fibers, and a technique capable of suppressing firing unevenness with high efficiency is disclosed ( Patent Document 4). However, since this oil composition has a very high viscosity, there is a problem that the stability of the oil is poor, and in addition, a highly viscous oil composition is deposited on the roll in the heat drying roll of the spinning process, and the oil composition is deposited on the roll. There was a problem that the fiber bundle was taken out and the operability was remarkably lowered.
Japanese Patent Publication No. 3-40152 JP 2001-172880 A JP-A-9-41226 JP 2007-39866 A

  As described above, in the prior art, the prevention of fusion between single fibers in each process, which is the purpose of the original oil agent, the operational stability that is indispensable industrially, and the high performance of carbon fiber bundles that meet recent demands An oil composition that combines all of the above cannot be obtained.

  The object of the present invention is to maintain the effect of preventing fusion between single fibers in the firing process, which is the role of the original carbon fiber precursor oil agent, while maintaining the operational stability of the spinning process of the precursor fiber bundle. The object of the present invention is to provide an oil composition for carbon fiber precursor acrylic fibers which is high and can improve the mechanical properties of the obtained carbon fiber bundle. Furthermore, it is in providing the carbon fiber precursor acrylic fiber bundle which can improve process passability and can improve productivity by making the oil agent composition adhere, and its manufacturing method.

  As a means for solving the above problems, the present invention uses a polyorganosiloxane having a cyano group as a component of an oil composition, as described below, to maintain the effect of preventing fusion and to have good process passability. The present invention provides an oil agent composition for acrylic fibers for a carbon fiber precursor that makes it possible to obtain a high-quality carbon fiber bundle. Moreover, the precursor fiber bundle which provided the oil agent composition and its manufacturing method are provided.

  The carbon fiber precursor acrylic fiber oil composition of the present invention is characterized by containing a polyorganosiloxane having a cyano group.

  In the carbon fiber precursor acrylic fiber oil composition of the present invention, the polyorganosiloxane having a cyano group preferably has a structure represented by the following formula (1).

(In the formula (1), R ^{1 to} R ⁷ are each independently a hydrocarbon group having 1 to 4 carbon atoms. A ¹ and A ² are each independently a hydrocarbon group having 1 to 4 carbon atoms. , A hydroxyl group or a cyano-modified group represented by the following formula (2): X represents a hydrocarbon group having 1 to 4 carbon atoms or a cyano-modified group represented by the following formula (2), provided that A ¹ , A ^At least one of ² and X is a cyano-modified group represented by the following formula (2): m is 0 to 1000, n is 0 to 700, and m + n = 10 to 1000.

(In the formula (2), R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms.)
In the oil agent composition for a carbon fiber precursor acrylic fiber of the present invention, in the polyorganosiloxane having the cyano group, R ^{1 to} R ⁷ , A ¹ and A ² in the formula (1) are all methyl groups, More preferably, X in the formula (1) is a side chain cyano-modified polydimethylsiloxane in which R ⁸ is a cyanopropyl group having 3 carbon atoms in the formula (2).

  The oil agent composition for carbon fiber precursor acrylic fiber of the present invention preferably contains 50 to 90% by mass of the polyorganosiloxane having a cyano group and 10 to 50% by mass of a nonionic emulsifier.

  The oil composition for carbon fiber precursor acrylic fiber of the present invention comprises 20-60 mass% of polyorganosiloxane having a cyano group, 10-30 mass% of a nonionic emulsifier, and the following formula (3) or the following formula ( It is preferable to contain 20-70 mass% of ester compounds shown by 4).

(In Formula (3), R ^{9 to} R ¹¹ are each independently a hydrocarbon group having 8 to 16 carbon atoms.)

(In Formula (4), R < ¹² > -R < ¹⁵ > is a C8-C16 hydrocarbon group each independently.)
The carbon fiber precursor acrylic fiber oil composition of the present invention preferably further contains 1 to 5% by mass of an antioxidant.

  The carbon fiber precursor acrylic fiber bundle of the present invention is characterized in that the oil agent composition is attached to the acrylic fiber bundle.

  The carbon fiber precursor acrylic fiber bundle of the present invention is a step of applying an aqueous emulsion solution (hereinafter also referred to as an emulsion) in which the oil composition forms micelles to an acrylic fiber bundle in a water-swelled state, And a step of drying and densifying the acrylic fiber bundle to which the aqueous emulsified solution is applied, and can be suitably produced by a method for producing a carbon fiber precursor acrylic fiber bundle.

  According to the present invention, the fusion between single fibers in the carbon fiber bundle manufacturing process can be effectively suppressed, and the oil composition attached to the drying roll after the oil application is not altered in the spinning process. An oil agent composition for a carbon fiber precursor acrylic fiber that can obtain a carbon fiber bundle that has good operational stability and that exhibits better mechanical properties than conventional products is obtained. Moreover, the carbon fiber precursor acrylic fiber bundle which provides the oil agent composition, and its manufacturing method are obtained.

  The inventors have achieved the operational stability of the spinning process of the precursor fiber bundle while maintaining the effect of preventing fusion between single fibers in the firing process, which is the role of the original oil agent for carbon fiber precursors. As a result of earnest search for an oil agent composition for carbon fiber precursor acrylic fiber that is high and can improve the mechanical properties of the obtained carbon fiber bundle, excellent fusion bonding is achieved by using polyorganosiloxane having a cyano group. It came to find the oil agent composition which has all of the prevention effect, operation stability, and the mechanical characteristic of a carbon fiber bundle. That is, the carbon fiber precursor acrylic fiber oil composition of the present invention makes it possible to simultaneously improve the operability of the carbon fiber bundle manufacturing process and the quality of the product.

  As the acrylic fiber bundle before the oil agent composition is adhered, an acrylic fiber bundle spun by a known technique can be used.

  Specific examples of preferred acrylic fiber bundles include acrylic fiber bundles obtained by spinning an acrylonitrile-based polymer.

  The acrylonitrile-based polymer is a polymer obtained by polymerizing acrylonitrile as a main monomer. The acrylonitrile-based polymer is not limited to a homopolymer obtained only from acrylonitrile, but may be an acrylonitrile-based copolymer using other monomers in addition to the main component acrylonitrile.

  The content of the acrylonitrile unit in the acrylonitrile-based copolymer is 96.0 to 98.5% by mass to prevent heat fusion of the fiber bundle in the firing step, the heat resistance of the copolymer, and the stability of the spinning dope From the viewpoint of the quality and the quality when made into a carbon fiber bundle. By setting the acrylonitrile unit to 96% by mass or more, excellent quality and performance of the carbon fiber bundle can be maintained without causing heat fusion of the precursor fiber bundle in the firing step when converting to the carbon fiber bundle. In addition, when spinning the precursor fiber bundle without lowering the heat resistance of the copolymer itself, adhesion between single fibers is performed in a process such as drying of the precursor fiber bundle or stretching with a heating roller or pressurized steam. Can be avoided. On the other hand, by setting the acrylonitrile unit to 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. Stable production of body fiber bundles becomes possible.

  The monomer other than acrylonitrile in the acrylonitrile copolymer can be appropriately selected from vinyl monomers copolymerizable with acrylonitrile. When selected from carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid, and itaconic acid, or monomers such as alkali metal salts, ammonium salts, and acrylamide, which have an action of promoting flameproofing reaction, It is preferable because it can promote the conversion. 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 vinyl monomer units copolymerizable with acrylonitrile in the acrylonitrile copolymer is preferably 1.5 to 4.0% by mass. The other monomer may be one type or two or more types.

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

  At this time, in order to obtain a dense coagulated yarn, it is preferable to prepare 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 17% by mass or more, more preferably 19% by mass or more. Furthermore, the spinning dope requires proper viscosity and fluidity, and the polymer concentration is preferably in a range not exceeding 25% by mass.

  Spinning methods include known spinning methods such as a wet spinning method in which a spinning solution is directly spun into a coagulation bath, a dry spinning method in which the spinning is coagulated in the air, and a dry and wet spinning method in which the spinning solution is once coagulated in the air and then coagulated in the bath. However, wet spinning or dry wet spinning is preferred to obtain a carbon fiber bundle having higher performance.

  The spinning shaping by the wet spinning method or the dry-wet spinning method can be performed by spinning the spinning solution into a coagulation bath from a nozzle having a hole with 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% by mass is preferable. The temperature of the coagulation bath is preferably 10 to 60 ° C.

  After the polymer is dissolved in a solvent and discharged as a spinning stock solution into a coagulation bath to be fiberized, stretching in a bath in which the coagulated yarn is stretched in a coagulation bath or in a stretching bath can be performed. Alternatively, it may be partially stretched in the air and then stretched in a bath, and an acrylic fiber bundle in a water swollen 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 one or more multistages, and the total ratio of stretching in the air and stretching in the bath can be stretched to 5 to 15 times. It is preferable from the viewpoint of the performance of the carbon fiber bundle.

  The oil composition comprises a polyorganosiloxane having a cyano group. The polyorganosiloxane having a cyano group may be one type or two or more types.

  The polyorganosiloxane having a cyano group preferably has a structure represented by the following formula (1).

(In the formula (1), R ^{1 to} R ⁷ are each independently a hydrocarbon group having 1 to 4 carbon atoms. A ¹ and A ² are each independently a hydrocarbon group having 1 to 4 carbon atoms. , A hydroxyl group or a cyano-modified group represented by the following formula (2): X represents a hydrocarbon group having 1 to 4 carbon atoms or a cyano-modified group represented by the following formula (2), provided that A ¹ , A ^At least one of ² and X is a cyano-modified group represented by the following formula (2): m is 0 to 1000, n is 0 to 700, and m + n = 10 to 1000.

(In the formula (2), R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms.)
Examples of the hydrocarbon group having 1 to 4 carbon atoms that can be selected as R ^{1 to} R ⁷ , A ^1, and A ² include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i- A butyl group, a sec-butyl group, or a t-butyl group. R ^{1 to} R ⁷ , A ¹ and A ² may all be the same or may contain different groups. R ⁸ is preferably a hydrocarbon group having 2 to 5 carbon atoms. Specific examples of the cyano modified group represented by the formula (2) include cyanoethyl, cyanopropyl, cyanobutyl, and cyanopentyl.

In the polyorganosiloxane having a cyano group, R ^{1 to} R ⁷ , A ¹ and A ^{2 in} the formula (1) are all methyl groups, X in the formula (1) is R ⁸ in the formula (2) More preferred is a side-chain cyano-modified polydimethylsiloxane that is 3 cyanopropyl groups.

  Moreover, regarding m and n in Formula (1), m is 0 to 1000, n is 0 to 700, m + n = 10 to 1000, preferably m + n = 100 to 800, and more preferably m + n = 300 to 600. is there. The values of m and n are not particularly limited as long as they are in the above ranges, but when X in formula (1) is a cyano-modified group represented by formula (2), the number of structural units n containing X is 1 to 1 It is preferable that it is 700, More preferably, it is 50-500. When m + n is smaller than 10, the thermal stability is lowered, and it becomes difficult to completely prevent fusion in the flameproofing step. Moreover, when m + n is larger than 1000, the viscosity is high, and the trouble of winding around the transport roll tends to occur in the spinning process due to the viscosity.

  The oil agent composition preferably further contains a nonionic emulsifier. When the oil composition contains a nonionic emulsifier, an emulsion of the oil composition can be stably formed. 1 type or 2 types or more may be sufficient as a nonionic emulsifier. Nonionic emulsifiers include, for example, higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, aliphatic ethylene oxide adducts, polyhydric alcohol aliphatic ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, aliphatic Polyamide glycol type nonionic surfactants such as amidoethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, aliphatic esters of glycerol, aliphatic esters of pentaerythritol, aliphatic esters of sorbitol Polyhydric alcohol type nonionic, such as aliphatic ester of sorbitan, aliphatic ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines Surface active agents. Polypropylene glycol ethylene oxide adducts are preferable, and a block copolymer of polypropylene oxide and polyethylene oxide is more preferable.

  The oil composition preferably contains 50 to 90% by mass of a polyorganosiloxane having a cyano group and 10 to 50% by mass of a nonionic emulsifier, and 70 to 90% by mass of a polyorganosiloxane having a cyano group, It is more preferable to contain 10-30 mass% of nonionic emulsifiers. When the polyorganosiloxane having a cyano group in the oil composition is less than 50% by mass, the heat resistance may not be effectively used. When the polyorganosiloxane exceeds 90% by mass, the amount of the emulsifier is inevitably reduced, The stability of the emulsion may deteriorate. If the nonionic emulsifier in the oil composition is less than 10% by mass, emulsification may be difficult and the stability of the emulsion may be deteriorated. The amount of organosiloxane decreases, and the heat resistance of the oil agent may decrease.

  The oil agent composition preferably further contains an ester compound represented by the following formula (3) or the following formula (4). When the oil composition contains an ester compound represented by the following formula (3) or the following formula (4), the thermal stability of the oil composition, the stability of the emulsion, and the process passability are improved. 1 type (s) or 2 or more types may be sufficient as the ester compound shown by Formula (3) or Formula (4).

(In Formula (3), R ^{9 to} R ¹¹ are each independently a hydrocarbon group having 8 to 16 carbon atoms.)

(In Formula (4), R < ¹² > -R < ¹⁵ > is a C8-C16 hydrocarbon group each independently.)
R ^{9 to} R ¹¹ in Formula (3) are each independently preferably a hydrocarbon group having 10 to 13 carbon atoms, and examples thereof include a decyl group, an undecyl group, a dodecyl group, and a tridecyl group. R ^{9 to} R ¹¹ in formula (3) may all be the same or may contain different groups. Specific examples of the ester compound represented by the formula (3) include trioctyl trimellitate, trinonyl trimellitate, tridecyl trimellitate, triundecyl trimellitate, tridodecyl trimellitate, tritridecyl trimellitate. Examples thereof include tate, tritetradecyl trimellitate, tripentadecyl trimellitate, and trihexadecyl trimellitate. As the ester compound represented by the formula (3), tridodecyl trimellitate is preferable.

R ^{12 to} R ¹⁵ in Formula (4) are each independently preferably a hydrocarbon group having 8 to 12 carbon atoms, and examples thereof include an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. R ^{12 to} R ¹⁵ in the formula (4) may all be the same or may contain different groups. Specific examples of the ester compound represented by the formula (4) include tetraoctyl pyromellitate, tetranonyl pyromellitate, tetradecyl pyromellitate, tetraundecyl pyromellitate, tetradodecyl pyromellitate, tetratridecyl pyrolo Examples include melitrate, tetratetradecyl pyromellitate, tetrapentadecyl pyromellitate, and tetrahexadecyl pyromellitate. As the ester compound represented by the formula (4), tetradecyl pyromellitate is preferable.

  The oil composition is composed of 20 to 60% by mass of a polyorganosiloxane having a cyano group, 10 to 30% by mass of a nonionic emulsifier, and 20 to 70% by mass of an ester compound represented by formula (3) or formula (4). It is preferable to contain. The balance of the three components in the oil composition is important, and if it is out of the above range, the thermal stability, the stability of the emulsion, and the process passability may decrease.

  The oil composition can further contain an antioxidant. This content is preferably in the range of 1 to 5 mass%, more preferably in the range of 1 to 3 mass%.

  Various known substances can be used as the antioxidant, and a phenol-based or sulfur-based antioxidant is preferable. 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) Butylphenyl) 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. The antioxidant may be used alone or as a mixture.

  Moreover, as an antioxidant, what melt | dissolves in the ester compound shown by Formula (3) or Formula (4) is more preferable. This is because the oil component that the antioxidant is desired to act on is an ester compound, and it is convenient to pre-dissolve in the ester compound as a method of uniformly mixing the antioxidant in the oil. This is the main reason.

  The oil composition may contain an antistatic agent in order to improve its properties. 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. The antistatic agent may be used alone or as a mixture.

  Furthermore, in order to improve the stability of the process, the stability of the oil composition, and the adhesion characteristics depending on the equipment and usage environment for attaching the oil composition to the acrylic fiber bundle, an antifoaming agent, preservative, antibacterial agent, penetrating agent Such additives may be appropriately added to the oil composition.

  In the present invention, a treatment for adhering a polyorganosiloxane having a cyano group and, if necessary, an oil composition containing a nonionic emulsifier, an ester compound, and an antioxidant to an acrylic fiber bundle in a water-swollen state. To do. Usually, the process which provides the aqueous | water-based emulsion solution in which the oil agent composition was disperse | distributed in water to the acrylic fiber bundle in a water swelling state is performed.

  Regarding the method for preparing the emulsion of the oil composition, for example, the oil composition is added to the water obtained by mixing the non-ionic emulsifier with the polyorganosiloxane having a cyano group and stirring the ester compound, and stirring the water. An emulsion dispersed in is obtained. When an antioxidant and / or an antistatic agent is contained, it is preferable to dissolve the antioxidant and / or the antistatic agent in an ester compound in advance. Mixing of each component or dispersion in water can be performed using propeller stirring, a homomixer, a homogenizer, or the like. In particular, when using a high viscosity amino-modified silicone, it is preferable to use an ultra-high pressure homogenizer that can pressurize to 150 MPa or more.

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

  As a method of imparting the oil agent composition to the acrylic fiber bundle in the water-swelled state, after adding the ion exchange water to the emulsion in which the oil agent composition is dispersed in water and diluting to a predetermined concentration, an oil agent treatment liquid is obtained. A technique of attaching to an acrylic fiber bundle in a water swelling state can be used.

  As a method of attaching the oil treatment liquid to the acrylic fiber bundle in the water-swollen state, the lower part of the roller is immersed in the oil treatment liquid and the acrylic fiber bundle is brought into contact with the upper part of the roller. A guide adhesion method in which an oil treatment liquid is discharged from a guide and an acrylic fiber bundle is brought into contact with the guide surface, a spray adhesion method in which a certain amount of the oil treatment liquid is sprayed from the nozzle onto the acrylic fiber bundle, and an acrylic fiber in the oil treatment liquid. After dipping the bundle, a known method such as a dip attachment method in which excess oil solution is removed by squeezing with a roller or the like can be used.

  From the viewpoint of uniform adhesion, the dip adhesion method is preferred in which the oil treatment liquid is sufficiently permeated into the acrylic fiber bundle to remove excess treatment liquid. 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.

  The adhesion amount of the oil composition to the acrylic fiber bundle is preferably 0.1 to 2% by mass with respect to the dry fiber mass of the acrylic fiber bundle after being dried and densified, which will be described later. More preferably, it is 5 mass%. When the adhesion amount of the oil agent composition is lower than 0.1% by mass, it may be difficult to sufficiently develop the original function of the oil agent. On the other hand, when the adhesion amount of the oil composition is higher than 2% by mass, the excessive oil agent composition may be polymerized in the firing step to cause adhesion between single fibers.

  In particular, when producing a precursor fiber bundle in which the oil agent composition is adhered in an amount of 0.1 to 2% by mass with respect to the dry fiber mass of the acrylic fiber bundle, the oil agent composition has an average particle diameter of 0.01 μm or more and 0.0. It is preferable to prepare an aqueous emulsified solution forming micelles of 5 μm or less. By carrying out like this, it becomes possible to provide an oil agent composition uniformly on the surface of an acrylic fiber bundle. In addition, the average particle diameter of the micelle which exists in an aqueous emulsified solution can be measured using a laser diffraction / scattering type particle size distribution measuring apparatus (trade name: LA-910, manufactured by Horiba, Ltd.).

  The precursor fiber bundle to which the oil composition is adhered is dried and densified in a 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 the temperature may vary depending on the drying state from the water-containing state, and the temperature is a method using a heating roller of about 100 to 200 ° C. Is preferred. At this time, the number of heating rollers may be one or more.

  It is preferable to perform pressurized steam drawing after drying because the denseness and orientation degree of the obtained precursor fiber bundle can be further increased. Pressurized steam stretching is a method of stretching in a pressurized steam atmosphere. Since high-strength stretching is possible, high-speed and stable spinning can be performed, and at the same time, the resulting precursor fiber bundle is dense. It also contributes to improving the degree of orientation.

  In the pressurized steam stretching, it is important to control the temperature of the heating roller immediately before the pressurized steam stretching apparatus to 120 to 190 ° C., and the variation rate of the steam pressure in the pressurized steam stretching to 0.5% or less. By controlling in this way, it is possible to suppress fluctuations in the draw ratio made on the precursor fiber bundle and fluctuations in tow fineness caused thereby. If the temperature of the heating roller is less than 120 ° C., the temperature of the precursor fiber bundle may not be sufficiently increased and the stretchability may be lowered.

  The pressure of water vapor in the pressurized steam stretching is preferably 200 kPa (gauge pressure, the same shall apply hereinafter) or more so that the stretching of the heated roller can be suppressed and the features of the pressurized steam stretching method appear clearly. The water vapor pressure is preferably adjusted as appropriate in consideration of the treatment time. However, when the pressure is increased, water vapor leakage may increase, and therefore, it is preferably about 600 kPa or less industrially.

  The precursor fiber bundle that has been dried and densified is passed through a roll at room temperature, cooled to room temperature, and then wound around a bobbin with a winder. Alternatively, it is transferred to a can and stored, and transferred to a firing step.

  The carbon fiber precursor acrylic fiber bundle of the present invention produced as described above is a carbon fiber bundle that can suppress fusion in the spinning process and firing process, has good processability, and has excellent quality and physical properties. Can be manufactured. A carbon fiber bundle obtained by such a carbon fiber precursor acrylic fiber bundle is suitable as a reinforcing fiber used for a fiber reinforced resin composite material used for various structural materials.

  The present invention will be described more specifically with reference to the following examples. The oil agent composition for the carbon fiber precursor acrylic fiber of the present invention, the precursor fiber bundle to which the oil agent composition is applied, and the method for producing the same are described below. It is not limited. In addition, the oil agent adhesion amount of the precursor fiber bundle, the heat resistance of the oil agent composition, the operation stability, and the strand strength of the carbon fiber bundle were evaluated by the following methods.

[Oil agent adhesion amount]
The precursor fiber bundle was dried at 105 ° C. for 1 hour, and then immersed in methyl ethyl ketone at 90 ° C. for 8 hours, and the oil agent composition adhered thereto was subjected to solvent extraction. The oil agent adhesion amount was determined from this difference by precisely weighing the mass of the precursor fiber bundle before and after this extraction.

[Heat-resistant]
In an aluminum petri dish (diameter: 45 mm, depth: 10 mm), 2.0 g of an oil agent base material in which the oil agent composition is dispersed in ion exchange water at a concentration of 30% by mass is precisely weighed, pre-dried at 105 ° C. for 1 hour, Heated at 250 ° C. for 5 hours. Observation was performed at regular time intervals (visual observation), and the time until gel started to be generated (gel start time) and the ratio of gelled sites after 5 hours (gelation degree) were evaluated. The longer the time until the gel starts to be generated and the smaller the degree of gelation, the better the heat resistance, and the better the processability in the drying process and flameproofing process after applying the oil composition, that is, gelation. It means that there are few fuzz and thread breakage induced by the silicone oil.

[Operational stability]
When the precursor fiber bundle was continuously produced for 24 hours, the operability was evaluated based on the frequency with which the single yarn was wound around and removed from the transport roll. The evaluation criteria were as follows.
○: Number of removals (times / 24 hours) ≦ 1
×: Number of removals (times / 24 hours)> 1
[Strand strength]
It measured according to the epoxy resin impregnation strand method prescribed | regulated to JIS-R-7608. The number of measurements was 10 times, and the average value was used as an evaluation target.

[Example 1]
An emulsion of the oil composition was prepared by the following method. Polycyano wherein R ^{1 to} R ⁷ , A ¹ and A ² in formula (1) are all methyl groups, X in formula (1) is formula (2) and R ⁸ is a cyanopropyl group having 3 carbon atoms. 90:10 (polycyanopropylmethylsiloxane: polyoxy) of propylmethylsiloxane (manufactured by Gelest, Inc., trade name: YMS-T31) and polyoxyethylene alkyl ether (trade name: Emulgen 707, manufactured by Kao Corporation) Ion-exchanged water was added to the mixture of ethylene alkyl ether) at a mass ratio so that the concentration of the oil composition was 30% by mass, and the mixture was emulsified with a homomixer. In this state, since the average particle size of the micelle of the oil composition is about 2 μm, it was further dispersed by a high-pressure homogenizer until the average particle size became 0.18 μm. The emulsion of the obtained oil agent composition was used as an oil agent stock solution in the following steps.

  The evaluation results of the heat resistance of the oil composition are shown in Table 1. Gelation was not confirmed under the test conditions.

  The oil agent composition was applied to the acrylic fiber bundle using the above oil solution stock solution. The acrylic fiber bundle to which the oil agent composition was adhered was prepared by the following method. A spinning stock solution in which acrylonitrile copolymer (composition ratio: acrylonitrile / acrylamide / methacrylic acid = 96/3/1 (mass ratio)) was dissolved in dimethylacetamide was prepared, and the pore size ( (Diameter) 40 μm, discharged from a spinning nozzle with 3000 holes, to obtain a coagulated yarn. The coagulated yarn was desolvated in a washing tank and stretched three times to obtain an acrylic fiber bundle in a water-swollen state.

  The acrylic fiber bundle in the above water-swelled state is guided to an oil treatment tank containing a treatment liquid obtained by diluting the above oil stock solution with ion-exchanged water, and after the oil composition is adhered, a roll having a surface temperature of 180 ° C. Then, the film was stretched 5 times in water vapor at a pressure of 0.2 MPa. The oil agent adhesion amount of the precursor fiber bundle obtained here and the evaluation results of the operational stability in the spinning process are shown together in Table 1.

  It was confirmed that the amount of oil adhesion was an appropriate amount. In addition, the operation stability was good, and there was no problem in continuous operation.

  This precursor fiber bundle was passed through a flameproofing furnace having a temperature gradient of 220 to 260 ° C., and further fired in a carbonization furnace having a temperature gradient of 400 to 1300 ° C. in a nitrogen atmosphere to obtain a carbon fiber bundle. The strand strength (CF strength) of the carbon fiber bundle obtained here is shown in Table 1. The CF strength was high and good.

[Examples 2 to 6]
Examples 2 to 6 were carried out in the same manner as in Example 1, except that the type and content of each component constituting the oil composition were changed. The ratio (mass percentage) of each component in the oil composition in each Example is shown in Table 1.

Details of the cyano-modified silicones A and B in Table 1 are described below. Incidentally, both are R ¹ to R ^7, both A ¹ and A ² are a methyl group in the formula (1), R ⁸ X in Formula (1) is in the formula (2) is cyanopropyl 3 carbon atoms The group is polycyanopropylmethylsiloxaneone.
Cyano-modified silicone A: polycyanopropylmethylsiloxane having a kinematic viscosity at 25 ° C. of 1000 mm ² / s (manufactured by Gelest, Inc., trade name: YMS-T31)
Cyano-modified silicone B: Polycyanopropylmethylsiloxane having a kinematic viscosity at 25 ° C. of 4000 mm ² / s (product name: # PS906, manufactured by United Chemical Technologies, Inc.)
Details of the ester compounds A and B in Table 1 are described below.
Ester compound A: Tridecyl trimellitate (dehydration condensate of trimellitic acid and decyl alcohol) in which R ^{9 to} R ¹¹ are all decyl groups having 10 carbon atoms in formula (3)
Ester compound B: Tetraoctyl pyromellitate (dehydration condensate of pyromellitic acid and octanol) in which R ^{12 to} R ¹⁵ are all octyl groups having 8 carbon atoms in formula (4)
The evaluation results of Examples 2 to 6 are shown in Table 1.

  In any Example, it did not gel by the heat resistance evaluation test of an oil agent composition, and it was confirmed that it is a thermally stable oil agent composition. The operation stability was good because the single yarn was not wound around the transport roll even in continuous operation for 24 hours. The CF strength was high and good.

  In the CF strength, Examples 1 and 2 in which the content of the cyano-modified silicone was 90% by mass were good. Further, when the emulsifier is increased by lowering the content of cyano-modified silicone (Example 3), when the ester compound is contained by lowering the content of cyano-modified silicone (Examples 4 to 6), It was confirmed that sufficient CF strength was obtained.

[Comparative Examples 1-6]
Comparative Examples 1 to 6 were carried out in the same manner as in Example 1 by changing the type and content of each component constituting the oil composition. The ratio (mass percentage) of each component in the oil agent composition in each comparative example is shown in Table 1.

Details of amino-modified silicones A and B in Table 1 are described below.
Amino-modified silicone A: amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 1100 mm ² / s (trade name: KF-8002, manufactured by Shin-Etsu Chemical Co., Ltd.)
Amino-modified silicone B: amino-modified polydimethylsiloxane having a kinematic viscosity at 25 ° C. of 4000 mm ² / s (trade name: FZ-3785, manufactured by Toray Dow Corning Co., Ltd.)
The evaluation results of Comparative Examples 1 to 6 are shown in Table 1.

  In Comparative Examples 1, 2, and 6 having a high amino-modified silicone content, the same CF strength was obtained as compared with each Example, but in Comparative Examples 3 to 5 in which the content of amino-modified silicone was low, The strength was low and not enough.

  In any of the comparative examples, gelation started within 5 hours in the heat resistance evaluation test of the oil composition, and the operation stability was poor. The reason for the poor operational stability is that the gelation start time is fast and the gelation rate after 5 hours is high, so that the precursor fiber bundle was taken by the transport roller by the gelled oil agent composition. From this result, when it produces continuously using the oil agent composition of Comparative Examples 1-6, it is judged that stable production is difficult besides the work accompanied by dangers, such as removal of the thread wound around a roller, increases.

  By using the oil agent composition for carbon fiber precursor acrylic fiber of the present invention, adhesion between single fibers in the firing step is effectively suppressed, and the operability is reduced due to gelation of the oil agent composition. Further, a carbon fiber bundle having high mechanical strength can be obtained. That is, according to the present invention, it is possible to obtain a carbon fiber precursor acrylic fiber bundle that can improve both the performance enhancement and the operational stability of the carbon fiber bundle.

  The carbon fiber bundle obtained from the carbon fiber precursor acrylic fiber bundle can be formed into a composite material after prepreg, and the composite material using the carbon fiber bundle obtained in the present invention is used for a golf shaft or fishing rod. It is useful because it can be suitably used for sports applications such as automobiles, aerospace applications, and various gas storage tank applications.

Claims (8)

  A carbon fiber precursor acrylic agent oil composition comprising a polyorganosiloxane having a cyano group. The oil composition for carbon fiber precursor acrylic fiber according to claim 1, wherein the polyorganosiloxane having a cyano group has a structure represented by the following formula (1).

(In the formula (1), R ^{1 to} R ⁷ are each independently a hydrocarbon group having 1 to 4 carbon atoms. A ¹ and A ² are each independently a hydrocarbon group having 1 to 4 carbon atoms. , A hydroxyl group or a cyano-modified group represented by the following formula (2): X represents a hydrocarbon group having 1 to 4 carbon atoms or a cyano-modified group represented by the following formula (2), provided that A ¹ , A ^At least one of ² and X is a cyano-modified group represented by the following formula (2): m is 0 to 1000, n is 0 to 700, and m + n = 10 to 1000.

(In the formula (2), R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms.) In the polyorganosiloxane having the cyano group, R ^{1 to} R ⁷ , A ¹ and A ² in the formula (1) are all methyl groups, and X in the formula (1) is R in the formula (2). 3. The oil composition for carbon fiber precursor acrylic fibers according to claim 2, wherein ⁸ is a side chain cyano-modified polydimethylsiloxane which is a cyanopropyl group having 3 carbon atoms.   The carbon fiber precursor acrylic fiber according to any one of claims 1 to 3, comprising 50 to 90% by mass of the polyorganosiloxane having a cyano group and 10 to 50% by mass of a nonionic emulsifier. Oil composition. 20-20 mass% of polyorganosiloxane which has the said cyano group, 10-30 mass% of nonionic emulsifiers, and 20-70 mass% of ester compounds shown by following formula (3) or following formula (4) The oil agent composition for an acrylic fiber for a carbon fiber precursor according to any one of claims 1 to 3.

(In Formula (3), R ^{9 to} R ¹¹ are each independently a hydrocarbon group having 8 to 16 carbon atoms.)

(In Formula (4), R < ¹² > -R < ¹⁵ > is a C8-C16 hydrocarbon group each independently.)   Furthermore, 1-5 mass% of antioxidant is contained, The oil agent composition for carbon fiber precursor acrylic fibers in any one of Claims 1-5 characterized by the above-mentioned.   A carbon fiber precursor acrylic fiber bundle, wherein the oil agent composition for a carbon fiber precursor acrylic fiber according to any one of claims 1 to 6 is attached to the acrylic fiber bundle.   It is a manufacturing method of the carbon fiber precursor acrylic fiber bundle of Claim 7, Comprising: The process which provides the aqueous | water-based emulsion solution in which the said oil agent composition forms the micelle to the acrylic fiber bundle in a water swelling state, And a step of drying and densifying the acrylic fiber bundle to which the aqueous emulsified solution is applied. A method for producing a carbon fiber precursor acrylic fiber bundle.