JP2018159138A - Oil agent composition for carbon fiber precursor acrylic fiber, carbon fiber precursor acrylic fiber bundle, carbon fiber, and carbon fiber precursor acrylic fiber bundle and carbon fiber production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high operational stability in a spinning process of a carbon fiber precursor acrylic fiber bundle while maintaining the effect of preventing fusion between single fibers in the firing process, and to obtain mechanical properties of the obtained carbon fiber bundle. Provided is an oil composition which can be improved. Further, the present invention provides a carbon fiber precursor acrylic fiber bundle capable of improving process passability and productivity, and a method for producing the same. SOLUTION: An oil composition for a carbon fiber precursor acrylic fiber containing a cyano group-containing polyorganosiloxane having specific physical properties is used, and an aqueous emulsified solution in which the oil composition forms micelles is formed into an acrylic fiber bundle. Give. [Selection diagram] None

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 heat-treat the acrylic fiber bundle in an oxygen-containing atmosphere at 200 ° C. or higher and 400 ° C. or lower to form a flame-resistant fiber bundle. A method is known in which a carbon fiber bundle is obtained by conversion and subsequent carbonization in an inert atmosphere at 1000 ° C. or higher. 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.
In order to solve the above problem, a technique relating to a silicone oil containing a cyano group in its structure has been disclosed (Japanese Patent Laid-Open No. 2010-43377). According to this technique, the gelation of silicone oil derived from the elimination of modified groups under high temperature conditions, which has been generated with conventional modified silicone oils, does not occur, and fiber bundles can be stably formed in the spinning and firing processes. It became possible to obtain. However, there have been problems such as generation of slight fusion caused by oil agent adhesion spots when the oil agent is applied to the fiber bundle and deterioration of quality resulting from the slight fusion.
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 3). 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 2010-43377 A 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.

In order to solve the above-mentioned problems, the present inventors have intensively studied to arrive at the present invention.
That is, the first aspect of the present invention is:
[1] An oil composition for a carbon fiber precursor acrylic fiber containing a polyorganosiloxane having a cyano group represented by the following formula (1):
The polyorganosiloxane having a cyano group satisfies the following (A), (B) and (C), and is an oil composition for a carbon fiber precursor acrylic fiber.
(A) The residual ratio a of polyorganosiloxane measured by the following method is 95% or more.
(B) The residual ratio b of the polyorganosiloxane measured by the following method is 1% or less.
(C) The degree of gelation of the polyorganosiloxane measured by the following method is 0%.
(Measurement method of residual rate a and residual rate b of polyorganosiloxane)
Put polyorganosiloxane in a mass W ₀ aluminum cell at room temperature, set in a thermal mass measuring device, hold at 100 ° C. for 5 minutes to remove moisture, and add the total W of aluminum cell and polyorganosiloxane mass W ₁ and then heated in an air atmosphere at a heating rate of 10 ° C./minute, and when the temperature reached 250 ° C., the total mass W ₂ of the aluminum cell and the polyorganosiloxane was measured, followed by 300 ° C. After switching the air atmosphere to a nitrogen atmosphere, the total W ₃ (g) of the mass of the aluminum cell and the polyorganosiloxane when the temperature reached 800 ° C. was further measured, and the residual ratio of the polyorganosiloxane was calculated according to the following formula: a and the residual ratio b are obtained.
Residual rate of polyorganosiloxane a [mass%]
= (W ₂ −W ₀ ) / (W ₁ −W ₀ ) × 100
Residual ratio b of polyorganosiloxane b [% by mass]
= (W ₃ −W ₀ ) / (W ₁ −W ₀ ) × 100
(Method for measuring the degree of gelation of polyorganosiloxane)
In an aluminum petri dish (diameter 45 mm, depth 10 mm), 2.0 g of polyorganosiloxane is precisely weighed, pre-dried at 105 ° C. for 1 hour, heated in air at 250 ° C. for 5 hours, cooled and dissolved in chloroform. Only the undissolved material is recovered, the recovered undissolved material is dried, the weight is measured, and the gelation degree of the polyorganosiloxane is calculated by the following formula.
Gelation degree of polyorganosiloxane [%]
= Mass of dried undissolved material [g] /2.0 [g] × 100
In (Equation ^(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 is a hydrocarbon group having 1 to 4 carbon atoms or a cyano-modified group represented by the following formula (2). However, at least one of A ¹ , A ² and X is a cyano modified group represented by the following formula (2). m is 0 or more and 1000 or less, n is 0 or more and 700 or less, and m + n = 10 or more and 1000 or less. )
(In the formula (2), R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms.)

[2] In the carbon fiber precursor acrylic fiber oil composition of the present invention, the polyorganosiloxane having a cyano group preferably satisfies the following (D) and (E).
(D) The viscosity of the polyorganosiloxane having a cyano group is 80 cSt or more and 5000 cSt or less.
(E) The cyano equivalent of the polyorganosiloxane having a cyano group is 500 g / mol.
It is 8000 g / mol or less.

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

[4] The oil composition for a carbon fiber precursor acrylic fiber according to the present invention contains 50% by mass to 90% by mass of the polyorganosiloxane having the cyano group and 10% by mass to 50% by mass of a nonionic emulsifier. It is preferable to contain below.

The second aspect of the present invention is
[5] A carbon fiber precursor acrylic fiber bundle comprising the oil agent composition for a carbon fiber precursor acrylic fiber according to any one of [1] to [4].

The third aspect of the present invention is
[6] A method for producing a carbon fiber precursor acrylic fiber bundle including the following steps (F), (G), and (H).
(F) The process which provides the oil agent composition for carbon fiber precursor acrylic fibers containing the polyorganosiloxane which has a cyano group to an acrylic fiber bundle (G) The acrylic by which the said oil agent composition for carbon fiber precursor acrylic fibers was provided. Fiber bundles,
A step of drying and densifying at a temperature of 150 ° C. or more and 180 ° C. or less (H) A step of heat-treating the acrylic fiber bundle after the drying and densification at a temperature of 130 ° C. or more and 170 ° C. or less for 3 to 10 minutes.

[7] In the method for producing a carbon fiber precursor acrylic fiber bundle of the present invention, in the step (F), the oil agent composition for a carbon fiber precursor acrylic fiber containing a polyorganosiloxane having a cyano group forms micelles. It is preferable to include a step of imparting the aqueous emulsion to the acrylic fiber bundle in a water-swollen state.

The fourth aspect of the present invention is
[8] A carbon fiber bundle production method in which a carbon fiber precursor acrylic fiber bundle is obtained by the production method according to [6] or [7], and the carbon fiber precursor acrylic fiber bundle is fired.

The fifth aspect of the present invention is as follows.
[9] A carbon fiber bundle having a strand strength measured according to JIS R7608 of 5.6 GPa or more and 6.2 GPa or less and a variation rate of the strand strength of 5% or less.

  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 earnestly searching for an oil agent composition for carbon fiber precursor acrylic fiber that is high and can improve the mechanical properties of the resulting carbon fiber bundle, by using a cyano group-containing polyorganosiloxane having specific physical properties, The present inventors have found an oil agent composition that has all of excellent anti-fusing effects, operational stability, and mechanical properties of carbon fiber bundles. 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% by mass or more and 98.5% by mass or less to prevent heat fusion of the fiber bundle in the firing step, heat resistance of the copolymer, spinning It is more preferable from the viewpoint of the stability of the stock solution and the quality when the carbon fiber bundle is formed. 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 the vinyl monomer unit copolymerizable with acrylonitrile in the acrylonitrile copolymer is preferably 1.5% by mass or more and 4.0% by mass or less. 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 is once solidified in the bath 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 mass% to 85 mass% is preferable. The temperature of the coagulation bath is preferably 10 ° C or higher and 60 ° C or lower.

  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 of 50 ° C. or higher and 98 ° C. or lower by dividing it into multiple stages of one or two times, and the total ratio of stretching in the air and stretching in the bath is stretched to 5 to 15 times. Is preferable from the viewpoint of the performance of the carbon fiber bundle obtained.

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 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 carbon atoms having 1 to 4 carbon atoms. A hydrogen group, 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 ^At least one of ¹ , ² and X is a cyano-modified group represented by the following formula (2): m is 0 or more and 1000 or less, n is 0 or more and 700 or less, and m + n = 10 or more and 1000 It is the following.)
(In 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.

About the polyorganosiloxane which has the said cyano group, it is preferable that the residual rate a of the polyorganosiloxane measured by the following method is 95% or more. If the residual ratio a of the polyorganosiloxane a, that is, the residual ratio of the polyorganosiloxane under the heat treatment conditions in the flameproofing process is 95% or more, the flameproofing furnace will not be scattered as a silicon compound such as silica in the flameproofing process. The contamination of the fibers can be reduced, and the fiber convergence can be kept sufficiently. From the viewpoint of suppression of silicon compound generation and fiber convergence, the polyorganosiloxane residual ratio a is more preferably 96% or more, and even more preferably 97% or more.
About the polyorganosiloxane which has the said cyano group, it is preferable that the residual rate b of the polyorganosiloxane measured by the following method is 1% or less. If the residual ratio b of the polyorganosiloxane, that is, the residual ratio of the polyorganosiloxane under the heat treatment conditions in the carbonization step is 1% or less, the residue derived from the oil agent present in the obtained carbon fiber is extremely small, and fluff Less performance variation. From the viewpoint of improving the quality of the carbon fiber, the polyorganosiloxane residual ratio b is more preferably 0.7% or more, more preferably 0.5%, most preferably derived from the oil agent. There is virtually no residue.

(Measurement method of residual rate a and residual rate b of polyorganosiloxane)
At room temperature, the polyorganosiloxane is placed in an aluminum cell, set in a thermal mass measuring apparatus, and kept at 100 ° C. for 5 minutes to remove moisture. The mass of the aluminum cell is W ₀ (g) _, and the total mass of _the aluminum cell and the oil composition is W ₁ (g). Next, after heating at a heating rate of 10 ° C./min in an air atmosphere, the same mass when reaching 250 ° C. was changed to W ₂ (g), and the air atmosphere was switched to a nitrogen atmosphere at 300 ° C., Furthermore, the same mass at the time of reaching 800 ° C. is defined as W ₃ (g). The mass was measured to the last three digits. The residual ratio of polyorganosiloxane is calculated by the following formula.
Residual rate of polyorganosiloxane a [mass%]
= (W ₂ −W ₀ ) / (W ₁ −W ₀ ) × 100
Residual ratio b of polyorganosiloxane b [% by mass]
= (W ₃ −W ₀ ) / (W ₁ −W ₀ ) × 100
About the polyorganosiloxane which has the said cyano group, the gelation degree of the polyorganosiloxane measured by the following method is 0%, and it is preferable that it does not gelatinize substantially.

(Method for measuring the degree of gelation of polyorganosiloxane)
In an aluminum petri dish (diameter 45 mm, depth 10 mm), 2.0 g of polyorganosiloxane is precisely weighed, pre-dried at 105 ° C. for 1 hour, cooled in air at 250 ° C. for 5 hours, and dissolved in chloroform. Only the undissolved material, ie the gelled part, is recovered. After drying the recovered undissolved material, its weight is measured, and the degree of gelation is calculated by the following formula.
Gelation degree of polyorganosiloxane [%]
= Weight of undissolved material after drying [g] /2.0 [g] × 100
The viscosity of the polyorganosiloxane having a cyano group is preferably 80 cSt or more and 5000 cSt or less. If the viscosity is 80 cSt or more, sufficient convergence can be imparted when adhered to the fiber bundle, but from the viewpoint of convergence, it is preferably 100 cSt or more, and more preferably 130 cSt or more. Good. On the other hand, if it is 5000 cSt or less, the fiber is not taken up by the roll due to the viscosity of the polyorganosiloxane, and a fiber bundle can be stably obtained, but in order to obtain a fiber bundle stably in the spinning process and firing process. Is preferably 4000 cSt or less, and more preferably 2000 cSt or less.
The cyano equivalent of the polyorganosiloxane having a cyano group is preferably 500 g / mol or more and 8000 g / mol or less. If the cyano equivalent is 500 g / mol or more, a polyorganosiloxane having a cyano group can be synthesized at a sufficiently low cost, but it is preferably 1000 g / mol or more, more preferably 1500 g / mol from the viewpoint of cost. It is good that it is above. On the other hand, if it is 8000 g / mol or less, a sufficient number of cyano groups are introduced in one molecule of the polyorganosiloxane, and the effect of improving heat resistance by having the cyano group can be obtained. To 5000 g / mol or less, more preferably 3000 g / mol or less.

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.
Regarding m and n in formula (1), m is 0 or more and 1000 or less, n is 0 or more and 700 or less, m + n = 10 or more and 1000 or less, preferably m + n = 100 or more and 800 or less, more preferably m + n = 300 or more and 600 or less. The values of m and n are not particularly limited as long as they are within 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 or more. It is preferably 700 or less, more preferably 50 or more and 500 or less. When m + n is greater than 10, there is sufficient thermal stability, and fusion in the flameproofing step can be generally prevented. Further, when m + n is smaller than 1000, the viscosity does not become too high, so that a fiber bundle can be obtained without any trouble in the spinning and firing processes.

  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% by mass or more and 90% by mass or less of a polyorganosiloxane having a cyano group and 10% by mass or more and 50% by mass or less of a nonionic emulsifier. It is more preferable to contain 10 mass% or more and 90 mass% or less of nonionic emulsifiers. If the polyorganosiloxane having a cyano group in the oil agent composition is contained in an amount of 50% by mass or more, the heat resistance can be effectively used, and if it is 90% by mass or less, a sufficient amount of emulsifier is ensured. And a stable emulsion can be obtained. If the nonionic emulsifier in the oil composition is 10% by mass or more, emulsification can be performed stably. The obtained emulsion also has sufficient stability, and if it is 50% by mass or less, a cyano group The amount of polyorganosiloxane having a sufficient amount is contained, and its heat resistance can be effectively utilized.
It is preferable that an oil agent composition contains 50 mass% or more and 90 mass% or less of polyorganosiloxane which has a cyano group, and 10 mass% or more and 50 mass% or less of nonionic emulsifiers. The balance of the two components in this oil agent composition is important, and within the above range, the thermal stability, the emulsion stability, and the process passability can all be satisfied.

The oil composition can further contain an antioxidant. This content is preferably in the range of 1% by mass to 5% by mass, and more preferably in the range of 1% by mass to 3% by 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) Eniru) propionate], tris (3,5-di -t- butyl-4-hydroxybenzyl) isocyanurate. Specific examples of the sulfur-based antioxidant include dilauryl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, and ditridecyl thiodipropionate. The antioxidant may be used alone or as a mixture.

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 this invention, the process which makes the polyorganosiloxane which has a cyano group, and the oil agent composition which mix | blended the nonionic emulsifier and antioxidant as needed adhere to the acrylic fiber bundle in a water swelling state is performed. 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. Mixing of each component or dispersion in water can be performed using propeller stirring, a homomixer, a homogenizer, or the like. In particular, when a high viscosity modified silicone is used, it is preferable to use an ultrahigh pressure homogenizer capable of pressurizing 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% by mass or more and 2% by mass or less 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 at least 1.5% by mass. If the adhesion amount of the oil composition is 0.1% by mass or more, the original function of the oil agent, such as preventing fusion of filaments or protecting the filament with an oil film and improving scratch resistance, should be sufficiently developed. I can do it. On the other hand, if the adhesion amount of the oil composition is 2% by mass or less, the oil composition is uniformly applied on the filament, and a fiber bundle can be stably obtained in both the spinning and firing steps.
In particular, in producing a precursor fiber bundle in which the oil agent composition is adhered to 0.1% by mass or more and 2% by mass or less 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. It is preferable to prepare an aqueous emulsified solution in which micelles of 0.5 μm or less are formed. 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 be substantially different depending on the drying state from the water-containing state, and the temperature is about 100 ° C. or more and 200 ° C. or less. 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 ° C. or more and 190 ° C. or less 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 120 ° C. or higher, the temperature of the precursor fiber bundle is sufficiently increased to obtain stretchability.
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.

Precursor fiber bundles that have been dried and densified have minor oily spots, and a slight fusion occurs in the firing process, resulting in a decrease in the quality of the carbon fiber that is finally obtained. It is desirable to have a heat treatment process that eliminates the unevenness of the oil agent. In the heat treatment step using the heating roller described above, the fiber bundle passing through the step is in a water-containing state, and most of the heat energy by the heat treatment is used by evaporation of moisture. On the other hand, in the heat treatment process described in this paragraph, the state of the fiber bundle passing through the process is almost completely dry, and the oil agent in which most of the heat energy by the heat treatment is applied to the fiber bundle and the fiber bundle. Used for temperature rise. In the latter case, as the temperature of the oil agent increases, the viscosity of the oil agent component decreases, and the filament is uniformly applied to each filament forming the fiber bundle. By such a mechanism, the precursor fiber bundle that has been dried and densified is further subjected to heat treatment, thereby eliminating the slight oil spot.
The heating temperature in the heat treatment step for eliminating the minor oily spots is preferably 130 ° C. or higher and 170 ° C. or lower. If the heating temperature is 130 ° C. or higher, it becomes possible for the oil agent spotted on the filament to spread sufficiently uniformly, but more preferably 140 ° C. or higher. Further, if the heating temperature is 170 ° C. or lower, a high-quality fiber bundle can be obtained without fusing the filaments together, but more preferably 160 ° C. or lower.
The heating time of the heat treatment step for eliminating the minor oily spots is preferably 3 minutes or more and 10 minutes or less. If the heating time is 3 minutes or longer, the oil agent that is spotted on the filament can spread out evenly and uniformly, more preferably 4 minutes or longer, and even more preferably 5 minutes or longer. Further, if the heating time is 10 minutes or less, a high-quality fiber bundle can be obtained without fusing the filaments together, but from the viewpoint of productivity, it is more preferably 8 minutes or less, and even more preferably 6 minutes or less. There should be.
As a drying method in the heat treatment step for eliminating the slight oil agent spots, a method using a heating roller or a method using hot air circulation is conceivable, but not limited thereto. Moreover, as a drying method of this heat processing process, only 1 type may be sufficient and 2 or more types may be combined, However, In order to process at a comparatively short time and low cost, it is preferable to perform the heat processing by a heating roller. .
The precursor fiber bundle that has been subjected to the heat treatment for eliminating the slight oil spotting is passed through a roll at room temperature, cooled to room temperature, and then wound around a bobbin by a winder. Alternatively, it is transferred to a can and stored, and transferred to a firing step.

It is preferable that the strand strength measured according to JISR7608 of the carbon fiber bundle obtained through arbitrary flameproofing treatment, carbonization treatment, electrolytic treatment, and sizing treatment in the firing step is 5.6 GPa or more and 6.2 GPa or less.
Further, the variation rate of the strand strength measured according to JIS R7608 is preferably 5% or less. If the variation rate of the strand strength of the carbon fiber bundle is 5% or less, the carbon fiber composite material using the carbon fiber bundle can be obtained with a sufficient quality. More preferably, the intensity fluctuation rate is 3% or less.
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, but the carbon fiber precursor acrylic fiber oil agent composition of the present invention, the precursor fiber bundle provided with the oil agent composition, and the production method thereof are limited by these. Is not to be done. In addition, the oil agent adhesion amount of the precursor fiber bundle, the oil agent heat resistance evaluation, the operation stability evaluation, and the carbon fiber strand strength evaluation were performed by the following methods.

[Remaining rate a and remaining rate b of polyorganosiloxane]
The polyorganosiloxane was placed in an aluminum cell at room temperature, set in a thermal mass measuring apparatus, and kept at 100 ° C. for 5 minutes to remove moisture. The mass of the aluminum cell was W ₀ (g) _, and the total mass of _the aluminum cell and the oil composition was W ₁ (g). Next, after heating at a heating rate of 10 ° C./min in an air atmosphere, the same mass when reaching 250 ° C. was changed to W ₂ (g), and the air atmosphere was switched to a nitrogen atmosphere at 300 ° C., Furthermore, the same mass at the time of reaching 800 ° C. was defined as W ₃ (g). The mass was measured to the last three digits. The residual ratio of polyorganosiloxane was calculated by the following formula.
Residual rate of polyorganosiloxane a [mass%]
= (W ₂ −W ₀ ) / (W ₁ −W ₀ ) × 100
Residual ratio b of polyorganosiloxane b [% by mass]
= (W ₃ −W ₀ ) / (W ₁ −W ₀ ) × 100

[Degree of gelation of polyorganosiloxane]
In an aluminum petri dish (diameter: 45 mm, depth: 10 mm), 2.0 g of polyorganosiloxane is precisely weighed, pre-dried at 105 ° C. for 1 hour, heated in air at 250 ° C. for 5 hours, cooled and dissolved in chloroform. Only the lysate, ie the gelled part, was collected. The recovered undissolved material was dried, its weight was measured, and the degree of gelation was calculated by the following formula.
Gelation degree of polyorganosiloxane [%]
= Weight of dried undissolved material [g] /2.0 [g] × 100
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 attaching the oil emulsion, that is, gelation. It means less fuzz and yarn breakage induced by silicone oil.

[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 carbon fiber precursor acrylic fiber bundle before and after this extraction.

[Operational stability evaluation]
When the carbon fiber precursor acrylic fiber bundle was continuously produced for 24 hours, the operability was evaluated based on the frequency with which the single 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

[Dispersion test of carbon fiber bundle]
The fiber bundle is cut to obtain a sample having a length of 3 mm. In a beaker having a capacity of 100 ml, 50 ml of chloroform and the sample were put, and stirred for 10 minutes at 600 rpm with a stirrer to disperse the fiber bundle in chloroform. Thereafter, the number of single fibers bonded per 6000 filaments (number of fiber aggregates) was measured to evaluate dispersibility. The evaluation criteria were as follows.
A: 0 ≦ Number of adhesions <5
○: 5 ≦ number of adhesions <20
Δ: 20 ≦ number of adhesions <100
×: 100 ≦ number of adhesion

[Carbon fiber bundle 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.

[Example 1]
An emulsion of the oil composition was prepared by the following method. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and A ¹ , A ^{2 in the} formula (1) are methyl groups, X is the formula (2) and R ⁸ is amino A polycyanopropylmethylsiloxane (A-1) having a viscosity of 130 cSt, a functional group equivalent of 6000 g / mol, and a polycyanopropylmethylsiloxane (A-1) having a functional group equivalent of 6000 g / mol; An oil agent composition mixed with 90:10 (polycyanopropylmethylsiloxane: polyoxyethylene alkyl ether) in a mass ratio of oxyethylene alkyl ether (B-1) (trade name: Emulgen 109P, manufactured by Kao Corporation) Ion exchange water was added so that the concentration of the product was 30 wt%, and emulsified with a homomixer. In this state, since the average micelle particle diameter was about 2 μm, the micelles were further dispersed by a high-pressure homogenizer until the average micelle particle diameter became 0.3 μm. This emulsion was used as an oil agent stock solution in the following steps.
The results of the residual rate a, residual rate b, and gelation degree of the polycyanopropylmethylsiloxane used are shown in Table 1. It was confirmed that the residual ratio a was sufficiently high and that the oil component remained sufficiently in the flameproofing process. Moreover, in the residual rate b, the residual rate was very small, and the residue derived from the oil agent hardly remained in the carbon fiber. Further, the degree of gelation was 0%, and it was confirmed that the gelation did not substantially occur.
Using the above oil stock solution, the oil composition is applied to the acrylic fiber bundle. The acrylic fiber bundle to which the oil agent composition was adhered was prepared by the following method. Acrylonitrile copolymer (composition ratio: acrylonitrile / acrylamide / methacrylic acid = 96/3/1 (mass ratio)) is dissolved in dimethylacetamide, a spinning stock solution is prepared, and the pore size is set in a coagulation bath filled with a dimethylacetamide aqueous solution. (Diameter) 60 μm, discharged from a spinning nozzle having a hole number of 6000 to obtain a coagulated yarn. The coagulated yarn was desolvated in a water washing tank and stretched 3 times to obtain an acrylic fiber bundle in a water swollen state.
The acrylic fiber bundle in the water-swelled state is guided to an oil agent treatment tank containing a treatment liquid obtained by diluting the oil agent stock solution with ion-exchanged water. After the oil agent composition is adhered, the acrylic fiber bundle is placed on a roll having a surface temperature of 180 ° C. After drying, 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 having 6,000 filaments and a total fineness of 4800 dtex obtained here, and the evaluation results of the operational stability evaluation 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 were no problems in continuous operation.
This carbon fiber precursor acrylic fiber bundle is passed through a flameproofing furnace having a temperature gradient of 220 to 260 ° C., and further baked in a carbonization furnace having a temperature gradient of 400 to 1300 ° C. in a nitrogen atmosphere. did. Table 1 shows the number of fused carbon fiber bundles obtained and the carbon fiber bundle strand strength (hereinafter also referred to as CF strength). The CF strength was high and good.

[Example 2]
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and A ¹ , A ^{2 in the} formula (1) are methyl groups, X is the formula (2) and R ⁸ is amino A polycyanopropylmethylsiloxane (A-1) having a viscosity of 410 cSt and a functional group equivalent of 5700 g / mol and having a viscosity of 450 cSt and a functional group equivalent of 5700 g / mol and having a cyano group substituted with a cyano group was used. Except that, the same operation as in Example 1 was performed.

[Example 3]
About the acrylic fiber bundle after drying densification, operation similar to Example 1 was performed except having further heat-processed for 10 minutes at the fiber bundle temperature of 130 degreeC using the heating roll.

[Example 4]
About the acrylic fiber bundle after drying densification, operation similar to Example 1 was performed except having further heat-processed for 5 minutes at the fiber bundle temperature of 150 degreeC using the heating roll.

[Example 5]
About the acrylic fiber bundle after drying densification, operation similar to Example 1 was performed except having further heat-processed for 3 minutes at the fiber bundle temperature of 170 degreeC using the heating roll.

[Comparative Example 1]
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and A ¹ , A ^{2 in the} formula (1) are methyl groups, X is the formula (2) and R ⁸ is cyano. The same operation as in Example 1 except that polycyanopropylmethylsiloxane (manufactured by Gelest, Inc., trade name: YMS-T31, A-3) having a viscosity of 1000 cSt as a propyl group and a functional group equivalent of 12000 g / mol was used. Went.

[Comparative Example 2]
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and A ¹ , A ^{2 in the} formula (1) are methyl groups, X is the formula (2) and R ⁸ is cyano. Example 1 except that polycyanopropylmethylsiloxane (united chemical technologies, Inc., trade name: # PS906, A-4) having a viscosity of 4000 cSt which is a propyl group and a functional group equivalent of 10,000 g / mol is used. The operation was performed.
Various evaluation results of Examples 2 to 5 and Comparative Examples 1 and 2 are summarized in Table 1.
In all of Examples 2 to 5, it was confirmed that the residual ratio a was sufficiently high, and that the oil component remained sufficiently in the flameproofing process. In the residual rate b, the residual rate was very small, and the residue derived from the oil agent was extremely difficult to remain in the carbon fiber. Further, the degree of gelation was 0%, and it was confirmed that the gelation did not substantially occur.
It was confirmed that the amount of oil adhesion was an appropriate amount. In addition, the operation stability was good, and there were no problems in continuous operation. In addition, the number of fusions and CF strength of the carbon fiber bundle are high and good. In addition, the number of fusions is reduced under the heat treatment conditions, the strand strength is further improved, and the strand strength fluctuation rate is reduced. It was good.
On the other hand, for Comparative Examples 1 and 2, it was confirmed that the residual rate a was high enough, and that the oil component remained sufficiently in the flameproofing process and did not gel substantially, the residual rate In b, the residual ratio was as high as 1% or more, and the result was that the residue derived from the oil agent was likely to remain in the carbon fiber. Although no major problems were observed with regard to continuous operability, Comparative Example 1 required many fusions between single fibers, and Comparative Examples 1 and 2 had low strand strength and a high rate of variation in strand strength. Performance and quality were not met.

By using the oil agent composition for acrylic fiber for carbon fiber precursor of the present invention, it is possible to suppress a decrease in operability due to gelation of the oil agent composition, and very little residue derived from the oil agent in the carbonization step, A high-quality carbon fiber bundle 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 (9)

An oil agent composition for a carbon fiber precursor acrylic fiber containing a polyorganosiloxane having a cyano group represented by the following formula (1),
The oil composition for a carbon fiber precursor acrylic fiber, wherein the polyorganosiloxane having a cyano group satisfies the following (A), (B), and (C).
(A) The residual ratio a of polyorganosiloxane measured by the following method is 95% or more.
(B) The residual ratio b of the polyorganosiloxane measured by the following method is 1% or less.
(C) The degree of gelation of the polyorganosiloxane measured by the following method is 0%.

(Measurement method of residual rate a and residual rate b of polyorganosiloxane)
Put polyorganosiloxane in a mass W ₀ aluminum cell at room temperature, set in a thermal mass measuring device, hold at 100 ° C. for 5 minutes to remove moisture, and add the total W of aluminum cell and polyorganosiloxane mass W ₁ and then heated in an air atmosphere at a heating rate of 10 ° C./minute, and when the temperature reached 250 ° C., the total mass W ₂ of the aluminum cell and the polyorganosiloxane was measured, followed by 300 ° C. After switching the air atmosphere to a nitrogen atmosphere, the total W ₃ (g) of the mass of the aluminum cell and the polyorganosiloxane when the temperature reached 800 ° C. was further measured, and the residual ratio of the polyorganosiloxane was calculated according to the following formula: a and the residual ratio b are obtained.
Residual rate of polyorganosiloxane a [mass%]
= (W ₂ −W ₀ ) / (W ₁ −W ₀ ) × 100
Residual ratio b of polyorganosiloxane b [% by mass]
= (W ₃ −W ₀ ) / (W ₁ −W ₀ ) × 100

(Method for measuring the degree of gelation of polyorganosiloxane)
In an aluminum petri dish (diameter 45 mm, depth 10 mm), 2.0 g of polyorganosiloxane is precisely weighed, pre-dried at 105 ° C. for 1 hour, heated in air at 250 ° C. for 5 hours, cooled and dissolved in chloroform. Only the undissolved material is recovered, the recovered undissolved material is dried, the weight is measured, and the gelation degree of the polyorganosiloxane is calculated by the following formula.

Gelation degree of polyorganosiloxane [%]
= Mass of dried undissolved material [g] /2.0 [g] × 100
In (Equation ^(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 is a hydrocarbon group having 1 to 4 carbon atoms or a cyano-modified group represented by the following formula (2). However, at least one of A ¹ , A ² and X is a cyano modified group represented by the following formula (2). m is 0 or more and 1000 or less, n is 0 or more and 700 or less, and m + n = 10 or more and 1000 or less. )
(In the formula (2), R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms.) The oil composition for carbon fiber precursor acrylic fibers according to claim 1, wherein the polyorganosiloxane having a cyano group satisfies the following (D) and (E).
(D) The viscosity of the polyorganosiloxane having a cyano group is 80 cSt or more and 5000 cSt or less.
(E) The cyano equivalent of the polyorganosiloxane having a cyano group is 500 g / mol.
It is 8000 g / mol or less. 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 a carbon fiber precursor acrylic fiber according to claim 1, wherein ⁸ is a side chain cyano-modified polydimethylsiloxane which is a cyanopropyl group having 3 carbon atoms.   Carbon as described in any one of Claims 1-3 which contains 50 to 90 mass% of polyorganosiloxane which has the said cyano group, and contains 10 to 50 mass% of nonionic emulsifiers. Oil agent composition for fiber precursor acrylic fiber.   The carbon fiber precursor acrylic fiber bundle containing the oil agent composition for carbon fiber precursor acrylic fibers as described in any one of Claims 1-4. The manufacturing method of a carbon fiber precursor acrylic fiber bundle including the process of following (F) (G) (H).
(F) The process which provides the oil agent composition for carbon fiber precursor acrylic fibers containing the polyorganosiloxane which has a cyano group to an acrylic fiber bundle (G) The acrylic by which the said oil agent composition for carbon fiber precursor acrylic fibers was provided. Fiber bundles,
A step of drying and densifying at a temperature of 150 ° C. or more and 180 ° C. or less (H) A step of heat-treating the acrylic fiber bundle after the drying and densification at a temperature of 130 ° C. or more and 170 ° C. or less for 3 to 10 minutes. In the step (F), an aqueous emulsion in which an oil composition for a carbon fiber precursor acrylic fiber containing a polyorganosiloxane having a cyano group forms micelles is applied to an acrylic fiber bundle in a water-swollen state. Including the step of
The manufacturing method of the carbon fiber precursor acrylic fiber bundle of Claim 6.   The manufacturing method of the carbon fiber bundle which obtains a carbon fiber precursor acrylic fiber bundle with the manufacturing method of Claim 6 or 7, and bakes the carbon fiber precursor acrylic fiber bundle.   The carbon fiber bundle whose strand strength measured according to JISR7608 is 5.6 GPa or more and 6.2 GPa or less, and the variation rate of strand strength is 5% or less.