JP2011202336A - Carbon fiber precursor acrylic fiber bundle, method for producing the same, and method for producing carbon fiber bundle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber precursor acrylic fiber bundle improving deterioration of operability with scales produced when a precursor fiber bundle to which a treating agent using a silicone compound as a principal component is applied is baked or the deterioration of physical properties of the carbon fiber bundle produced when the precursor fiber bundle to which a non-silicone-based treating agent is applied is baked, and to provide a method for producing the carbon fiber bundle having excellent mechanical properties and quality.SOLUTION: The treating agent includes 60-100 mass% of following components [A] and [B] in the treating agent, and the total pickup of the following components [A] and [B] in the treating agent is 0.05-3.0 pts.mass based on 100 pts.mass of the fiber bundle. Furthermore, the mass ratio [A]:[B] in the treating agent is within the range of (30:70)-(70:30). [A] a modified silicone; and [B] a monoester or a diester of a carboxylic acid having 4-8C monovalent branched type saturated hydrocarbon with a monohydric or a dihydric alcohol having 3-20C monovalent hydrocarbon.

Description

  The present invention relates to a carbon fiber precursor acrylic fiber bundle (hereinafter also simply referred to as a precursor fiber bundle) suitable for producing a carbon fiber having excellent quality and physical properties, and a carbon fiber produced using the carbon fiber precursor acrylic fiber bundle. The present invention relates to a method for manufacturing a bundle.

  Conventionally, as a method for producing a carbon fiber bundle, the precursor fiber bundle is converted into a flame-resistant fiber bundle by heat treatment in an atmosphere containing 200 to 300 ° C., and subsequently carbon in an inert atmosphere of 1000 ° C. or more. There is known a method of obtaining a carbon fiber bundle by converting into a carbon fiber. 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 flameproofing process for converting the precursor fiber bundle into a flameproofed fiber bundle, fusion occurs between the single fibers, and the flameproofing process and the subsequent carbonization process (hereinafter referred to as the flameproofing process and the carbonization process are combined). In some cases, process failures such as fluff and yarn breakage may occur. Moreover, the carbon fiber bundles fired while being fused have a remarkable decrease in strand strength as the surface defects increase.

In order to avoid fusion between single fibers, it is known that selection of a treatment agent to be attached to the precursor fiber is important, and many compounds have been studied. For example, silicone-based treatments containing modified silicones such as amino-modified silicones, epoxy-modified silicones, and polyether-modified silicones are widely used because of their high heat resistance and the effect of suppressing the fusion of single fibers. ing. (For example, see Patent Documents 1 and 2)
On the other hand, silicone processing agents have the following problems. The silicone-based treatment agent disclosed in the patent document prevents fusion between single fibers by causing the silicone component to undergo a crosslinking reaction by heating to increase viscosity and gel. Therefore, the gelled treatment agent may fall off from the fiber surface and accumulate on the roll in the precursor fiber manufacturing process or the flameproofing process, thereby inducing fluff or thread breakage. In the firing process, most of the silicone compound in the treatment agent is decomposed and scattered, and a part of the silicon compound forms silicon compounds such as silicon oxide, silicon carbide, and silicon nitride in the firing furnace, and these scales are foreign matters. As a result, process stability and product quality were reduced.

  Since the silicone-based treatment agent has such problems, a treatment agent (non-silicone treatment agent) using a non-silicone compound as a main component has also been proposed. As such a technique, a fatty acid ester of an alkylene oxide adduct of bisphenol A (see Patent Document 3), an ester of a dihydric alcohol or polyoxyalkylene diol and a carboxylic acid (see Patent Document 4), alkyl or An example using an alkenylthio fatty acid ester (see Patent Document 5) is given.

  Non-silicone-based treatment agents have advantages such as the absence of generation of silicon compounds in the firing process and the low cost of raw materials, but many of them are inferior in thermal stability compared to silicone compounds. Therefore, the increase in surface defects due to the fusion of single fibers in the firing process often occurs as compared to the case of using a silicone-based treatment agent. Since the product is inferior to the silicone-based treatment agent in terms of the reduction in strand strength, the application of the non-silicone treatment agent has been limited.

  In order to solve these problems, proposals have been made to combine a silicone compound and a non-silicone compound (see Patent Documents 6 to 8). However, the effect of preventing the fusion between the single fibers is not sufficient, or the effect of reducing the amount of silicon compound scattering in the firing process is insufficient. Further, Patent Document 9 proposes a method in which a non-silicone compound is applied in the first stage, and then a silicone compound is applied and dried in the second stage after drying and washing. However, in this method, it is difficult to control the amount of treatment agent attached to a constant amount by washing, and the first-stage treatment agent is mixed in the second-stage treatment agent bath, and the composition of the treatment agent is not constant. There were also problems such as.

  As described above, in the precursor fiber bundle provided with only the non-silicone treatment agent according to the prior art, the precursor fiber bundle provided with the silicone treatment agent in terms of process stability and expression of mechanical properties of the carbon fiber bundle. It tends to be inferior, and a high-quality carbon fiber bundle cannot be obtained stably. Moreover, a precursor fiber bundle to which a non-silicone compound and a silicone compound are used in combination and a treatment agent with a reduced content of the silicone compound is applied cannot stably obtain a high-quality carbon fiber bundle.

  In other words, the problem of silicon compound generation in the firing process that originates from silicone treatment agents and the problem of deterioration of physical properties of carbon fibers due to non-silicone treatment agents are in an integrated relationship. It hasn't been done yet.

JP 2006-188895 A JP 2006-183159 A JP 2004-143645 A JP 2001-248076 A Japanese Patent Publication No. 61-15186 JP 2008-196097 A JP 2000-199183 A International Publication No. 2009/060834 Pamphlet JP 2005-89883 A

  The object of the present invention is to reduce the operability due to scale generated when a precursor fiber bundle to which a treatment agent containing a silicone compound as a main component is applied is fired, or to mix a non-silicone compound as a main component or with a silicone compound. Another object of the present invention is to provide a carbon fiber precursor acrylic fiber bundle that can improve the deterioration of the physical properties of the carbon fiber bundle generated when the precursor fiber bundle to which the non-silicone treatment agent is applied is fired. Furthermore, it is providing the manufacturing method of the carbon fiber bundle excellent in the mechanical physical property and quality obtained by baking this carbon fiber precursor acrylic fiber bundle.

In the treatment agent combining a silicone compound and a non-silicone compound, the present inventors have insufficient effect of preventing fusion between single fibers because the compatibility between the silicone compound and the non-silicone compound is low. Since the mixture of the silicone compound and the non-silicone compound does not uniformly adhere to the surface of the body fiber bundle and the separation occurs, the effect of preventing the fusion between the single fibers is not sufficient at the site where the non-silicone compound is unevenly distributed. Under the hypothesis that the treatment yarn containing a silicone compound and a non-silicone compound, the process yarns were analyzed in detail, focusing on the compatibility of the two components. Separation of the treatment agent components on the precursor fiber bundle surface But I found out that it was the cause. That is, in the conventional technology, the compatibility in the state of the blend of the treatment agent before being applied to the fiber bundle is good, and although component separation on the fiber surface is not seen immediately after application to the precursor fiber bundle, It was found that separation of the treating agent component occurred on the surface of the fiber after passing through a drying step in which the precursor fiber bundle was processed at a high temperature and densified in the yarn forming step. Thus, it is thought that the fusion inhibitory effect of a silicone compound became inadequate when both components isolate | separated in the yarn-making process after providing a processing agent.
In other words, in order to suppress the fusion between single fibers in the flameproofing process, it is not sufficient that they are mixed in the state of the treatment agent mixture, and the precursor fiber bundle surface has a high temperature in the spinning process. It is necessary that separation does not occur even under conditions, and furthermore, a carbon fiber precursor acrylic fiber bundle provided with an ester compound having a specific branched saturated hydrocarbon chain and a silicone compound in an appropriate ratio is used. Thus, it has been found that separation of the treatment agent composition on the fiber surface can be suppressed.

That is, the carbon fiber precursor acrylic fiber bundle of the present invention is an acrylic fiber bundle having a treatment agent attached to the surface, and the treatment agent comprises the following [A] component and the following [B] component. 60 to 100% by mass in the total amount of the following [A] component and the following [B] component in the treatment agent is 100 parts by mass of the acrylic fiber bundle before the treatment agent is attached. 0.05 to 3.0 parts by mass, and the mass ratio of the following [A] component to the following [B] component in the treatment agent is [A]: [B] = 30: 70 to 70:30. It is the range of these.
[A] Modified silicone [B] Compound represented by the following formula (1) and / or formula (2)

(In Formula (1), R ₁ is a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and A ₁ is a monovalent hydrocarbon group having 3 to 20 carbon atoms.)

(In Formula (2), R ₂ and R ₃ are each a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and may be the same or different. A ₂ has 3 to 20 carbon atoms. Divalent hydrocarbon group).

  In the present invention, the [A] component is preferably an amino-modified silicone.

In addition, at least one of R ₁ in Formula ( ₁ ) and R ₂ and R ₃ in Formula (2) of the [A] component and / or [B] component contained in the treatment agent is a t-butyl group or A branched octyl group is preferred.
In the present invention, the [B] component is a diester obtained from neopentanoic acid and 2,4-diethyl-1,5-pentanediol, a diester obtained from neopentanoic acid and 3-methyl-1,5-pentanediol, isononane Selected from diesters obtained from acid and neopentyl glycol, neopentanoic acid isostearyl ester, neopentanoic acid octyldodecyl ester, isononanoic acid isotridecyl ester, isononanoic acid isodecyl ester, isononanoic acid isononyl ester, isononanoic acid ethylhexyl ester Preferably it is at least one compound.

  Moreover, the carbon fiber precursor acrylic fiber bundle of the present invention was applied with the treatment agent by passing the acrylic fiber bundle before applying the treatment agent through a bath filled with the dispersion of the treatment agent. Then, it is preferable to manufacture with the manufacturing method which has the process of giving the processing agent after performing the drying process and also giving the processing agent after performing the drying process.

  The carbon fiber precursor acrylic fiber bundle of the present invention is preferably used for producing a carbon fiber bundle by making it flame resistant in an oxygen-containing atmosphere and then carbonizing it.

  When the carbon fiber precursor acrylic fiber bundle of the present invention is used, it suppresses the generation of silicon compounds that interfere with the process while maintaining the effect of suppressing the fusion between single fibers in the carbon fiber bundle manufacturing process. Can do. As a result, the operability is improved, and the obtained carbon fiber can exhibit better mechanical properties than conventional products.

Image determined that separation of treatment agent did not occur in SEM observation of Example Image determined that separation of treatment agent occurred in SEM observation of Example

In the carbon fiber precursor acrylic fiber bundle of the present invention, the treatment agent is attached to the surface, and the treatment agent contains the following [A] component and the following [B] component in the treatment agent in an amount of 60 to 100% by mass. In addition, the total adhesion amount of the following [A] component and the following [B] component in the treatment agent is 0.05 to 3.0 with respect to 100 parts by mass of the acrylic fiber bundle before the treatment agent is adhered. The mass ratio of the following [A] component and the following [B] component in the treatment agent is in the range of [A]: [B] = 30: 70 to 70:30. And
[A] Modified silicone [B] Compound represented by the following formula (1) and / or formula (2)

(In Formula (1), R ₁ is a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and A ₁ is a monovalent hydrocarbon group having 3 to 20 carbon atoms.)

(In Formula (2), R ₂ and R ₃ are each a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and may be the same or different. A ₂ has 3 to 20 carbon atoms. Divalent hydrocarbon group).

  In the present invention, the configuration of the treatment agent applied to the fiber bundle is the most important.

  The [A] component in the treatment agent is a component that has been known to have a high effect of suppressing fusion, but has the problems described above, and the [B] component is a non-silicone compound. Is highly compatible with the [A] component by having the above-mentioned specific structure, and even after passing through all the spinning processes, it does not separate from the [A] component on the surface of the precursor fiber bundle. By using together, even a small amount of the [A] component can cover the entire surface of the precursor fiber bundle, so even if the amount of application of the [A] component is reduced, a decrease in strength can be suppressed. .

  That is, by using such a specific treatment agent, it has become possible to solve both of the problems that could not be achieved in the past, such as reducing the silicone compound content and improving the carbon fiber bundle strength, and the manufacturing process. We were able to improve the operability and product quality at the same time.

  As described above, the main part of the present invention is to apply a specific treating agent, but since it is obtained by giving a specific ratio to the precursor fiber bundle in the yarn forming process, the treating agent is given below. A description will be made in order from the contents related to the yarn production of the precursor fiber bundle.

  The acrylic fiber bundle used for producing the carbon fiber precursor acrylic fiber bundle of the present invention before the treatment agent composition is attached may be an acrylic fiber bundle obtained by spinning an acrylonitrile polymer. There is no particular limitation, and an acrylic fiber bundle spun by a known technique can be used.

  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 component of the acrylonitrile copolymer used in the present invention is preferably 95 mol% or more of acrylonitrile from the viewpoint of the stability of the spinning solution, and more preferably 98 mol% or more. The acrylonitrile copolymer used in the present invention preferably contains 0.1 mol% or more of a flame resistance promoting component which promotes flame resistance and is copolymerizable with acrylonitrile. When such a component is added in a large amount, abnormal heat generation may be caused at the time of flame resistance. Therefore, it is preferable to use a copolymer copolymerized in a range of 5 mol% or less, more preferably 2 mol% or less. As such flame resistance promoting component, it is preferable to use at least one monomer selected from the group consisting of acrylic acid, methacrylic acid and itaconic acid. In addition to the flame resistance promoting component, from the viewpoint of enhancing the solubility in a solvent, for example, a (meth) acrylic acid alkyl ester such as methyl acrylate may be copolymerized.

  The spinning solution can be obtained by employing a polymerization method such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. As the solvent used in the spinning solution, both organic and inorganic solvents can be used, and it is particularly preferable to use an organic solvent. Specifically, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and the like are preferable, and dimethyl sulfoxide is particularly preferable.

  As the spinning method, a known spinning method such as a dry spinning method in which the above spinning solution is coagulated in the air or a wet spinning method in which the spinning solution is coagulated in a coagulation bath liquid can be used as appropriate, but the wet spinning method is particularly preferably used.

  In the spinning shaping by the wet spinning method, the spinning solution is discharged directly into the coagulation bath directly from the spinneret or after passing through the air to obtain a coagulated yarn. The coagulation bath liquid is preferably composed of a solvent used for the spinning solution and a coagulation accelerating component from the viewpoint of easy solvent recovery, and water is preferably used as the coagulation accelerating component. The ratio of the spinning solvent and the coagulation promoting component in the coagulation bath liquid and the coagulation bath liquid temperature are appropriately selected and used in consideration of the denseness, surface smoothness, spinnability, and the like of the obtained coagulated yarn.

  The coagulated yarn obtained by spinning is washed with water in one or more water baths adjusted to a temperature of 20 ° C. to 98 ° C. and subjected to primary stretching. The primary draw ratio can be appropriately set as long as thread breakage or adhesion between single fibers does not occur, but in order to obtain a precursor fiber with a smoother surface, the primary draw ratio is 5 times or less. It is preferable. The primary draw ratio is preferably 1.1 times or more from the viewpoint that the draw ratio of the whole yarn production process can be increased.

  Further, the maximum temperature of the primary stretching bath is preferably 50 ° C. or higher, and more preferably 70 ° C. or higher, thereby improving the denseness of the precursor fiber obtained through the drying step. This is preferable because it comes out. Further, when the maximum temperature of the primary stretching bath exceeds 99 ° C., the water is vigorously evaporated and the production energy consumption is increased. Therefore, the maximum temperature of the primary stretching bath is preferably 99 ° C. or less.

  As a means for drying the yarn bundle in the drying step subsequent to the primary stretching, a means for bringing the yarn bundle into direct contact with a plurality of heated rollers is preferably used. The higher the drying temperature, the better from the viewpoint of productivity, and it is preferable to set the drying temperature as high as possible without causing fusion between single fibers. Specifically, the drying temperature is preferably 150 ° C to 200 ° C, more preferably 180 ° C to 190 ° C. When the drying temperature exceeds 200 ° C., the fusion between single fibers in the drying process becomes significant. When the treatment agent is applied to the water-swelling yarn, the gelation of the treatment agent occurs when the drying temperature exceeds 200 ° C., so that the treatment agent can follow the fiber drawing in the subsequent secondary drawing step. In some cases, the non-adhered portion of the treatment agent is generated after the fiber bundle is stretched, and the effect of the present invention may not be achieved. The drying time is set to a time sufficient for the swollen yarn bundle to dry. Specifically, the drying time is about 15 to 60 seconds. Further, it is preferable that the yarn bundle is brought into contact with the roller in a state where the yarn bundle is widened as much as possible so that the heating state to the yarn bundle becomes uniform.

  From the viewpoint of improving the denseness of the obtained precursor fiber, the dried yarn bundle is preferably further subjected to secondary stretching. As the method of secondary stretching, pressurized steam stretching, dry heat stretching, or the like can be used, but pressurized steam stretching is preferable from the viewpoint of improving productivity. The water vapor pressure or temperature at the time of pressurized water vapor stretching or the secondary stretching ratio can be appropriately selected and used within a range where yarn breakage and fluff generation do not occur.

  Thereafter, the yarn bundle is wound up by a winder to obtain a package of an acrylic fiber bundle.

  The fineness (single fiber fineness) of the single fiber constituting the yarn bundle of the precursor fiber is preferably 0.1 to 2.0 dTex, more preferably 0.3 to 1.5 dTex, and still more preferably 0.8. 5 to 1.2 dTex. The smaller the single fiber fineness is, the more advantageous it is in terms of improving the tensile strength and elastic modulus of the obtained carbon fiber. However, since the productivity is often lowered, it is preferable to select it in consideration of the balance between performance and cost. .

  The number of single fibers constituting the yarn bundle of the precursor fibers is preferably 1000 to 96000, more preferably 12000 to 48000, and further preferably 24,000 to 48000. Here, the number of single fibers constituting the yarn bundle of the precursor fibers means the number of single fibers immediately before the flameproofing treatment. From the viewpoint of productivity, the number of single fibers is preferably as large as possible. If the number of single fibers is too small, productivity often deteriorates, and if it is too large, uneven firing is likely to occur during flame resistance.

  In the present invention, a known method can be used as a treatment agent application method. For example, the treatment agent can be applied in one step using the following method. That is, it is a method in which the treating agent is made into an aqueous dispersion with an emulsifier, and the aqueous dispersion is applied to the precursor fiber bundle and dried. As the dispersion medium to be used, water is preferably used from the viewpoint of the working environment. Examples of the applying means include an immersion method, a spray method, a touch roll method, and a guide oil supply method. As the step of applying the treating agent, it can be given in any step of the yarn forming step, but if the treating agent as an aqueous dispersion is applied to the acrylic fiber bundle in the water-swollen state after the primary stretching described above. In particular, the drying of the precursor fiber bundle and the drying process of the solvent can be simplified together, which is particularly preferable.

  Moreover, the method of providing in two steps is mentioned as another aspect of the provision method of the processing agent in this invention. That is, in the same manner as described above, the oil agent is applied to the water-swelling yarn as the first step, and after the drying and densification treatment, the oil agent is further applied as the second step. As described later, the component [B] in the present invention is excellent in compatibility with the component [A] and has a low viscosity. Guide oil supply method can be used. In the touch roll method and the guide oil supply method, a predetermined amount of treatment agent can be added to the precursor fiber bundle, and a process of removing a dispersion medium such as water is not necessary, which is preferable in terms of cost and equipment cost. . Moreover, you may change a component ratio by the 1st step | paragraph and the 2nd step | paragraph about the kind of oil agent provided to a precursor fiber, a component, and the adhesion amount. In particular, the component ratio of [A] in the first-stage treatment agent is preferably 0 to 0.1 parts by mass per 100 parts by mass of the precursor fiber bundle. By setting it as this adhesion amount range, the gum-up on a dry densification roll can be suppressed and the quality of a precursor fiber can be maintained favorable over a long period of time. More preferably, it is 0-0.05 mass part. In any method, after the treatment agent is applied to the fiber bundle, in the step of drying the solvent / dispersion medium, the treatment agent mixture spreads so as to cover the fiber surface. These components can be uniformly applied to the fiber surface.

  As the step of applying the treating agent, it can be given in any step of the yarn forming step, but if the treating agent as an aqueous dispersion is applied to the acrylic fiber bundle in the water-swollen state after the primary stretching described above. In particular, the drying of the precursor fiber bundle and the drying process of the solvent can be simplified together, which is particularly preferable.

  In the present invention, the treatment agent imparted to the precursor fiber bundle is [A] a modified silicone compound, [B] the compound represented by the above formula (1) and / or the above formula (2) in a mass ratio [A]: [B] = 30: 70 to 70:30 Inclusive, [A] component and [B] component are included in the treatment agent in an amount of 70 to 99% by mass.

  [A] component of the processing agent used in the present invention is a modified silicone compound. In the present invention, the modified silicone compound refers to a silicone compound that has a silicone skeleton and has an organic functional group at the terminal and / or side chain thereof and can be crosslinked by heating in an oxygen atmosphere. Since it has the effect of preventing fusion between single fibers as described later, it is a necessary component for the treatment agent of the present invention by crosslinking and gelation upon heating. As such modified silicone, known ones such as amino-modified silicone, polyether-modified silicone, epoxy-modified silicone, and carbinol-modified silicone can be used, and amino-modified silicone is particularly preferable.

As the amino-modified silicone used in the present invention, any of primary side-chain amino-modified type, 1,2-side-chain amine-modified type, and both-terminal amino-modified type can be used. In view of the heat resistance of the silicone compound and the reactivity in the flameproofing step described in the next section, the kinematic viscosity at 25 ° C. is 1000 to 5000 mm ² / s and the amino equivalent is 1000 to 10,000 g / mol. preferable.

  Here, the mechanism by which the modified silicone responds to the effect of suppressing single fiber fusion will be described. In the carbon fiber manufacturing method for firing the acrylic fiber bundle, the precursor acrylic fiber bundle is flame-resistant in an oxygen-containing atmosphere of 200 ° C. to 300 ° C., and then carbonized in an inert atmosphere of 1000 ° C. or higher. In this process, the flame resistance process is a process in which the precursor fiber bundle is treated at a temperature of 200 ° C. or higher to be partially crosslinked and infusible. In the flameproofing process, the surface of the single fiber in the precursor fiber bundle is melted, and the single fiber in the precursor fiber bundle is easily brought into contact with each other. In the precursor fiber bundle in which the agent is previously adhered to the surface, the modified silicone compound is a precursor obtained by coating the surface of a single fiber with a thin film of a silicone compound that is crosslinked and gelled at a high temperature of 200 ° C. or higher in an oxygen atmosphere. It is considered that fusion is suppressed by preventing contact between single fibers in the fiber bundle.

  If the amount of the modified silicone applied to the precursor fiber is reduced, the film thickness of the gelled silicone compound covering the precursor single fiber decreases, and a portion not covered by the gelled silicone compound thin film is generated. It is considered that fusion occurs at that portion.

  In other words, it can be said that the optimum amount and state of adhesion of the modified silicone is to cover the fibers evenly and maintain a certain thickness.

  In the present invention, since the effect by the combination with the [B] component described below has an important meaning, only the qualitative meaning of the above-mentioned [A] component is shown here, and the adhesion amount, the content ratio, etc. The quantitative contents of will be described later together with the [B] component.

  [B] component of the processing agent used in the present invention is a compound represented by the formula (1) and / or formula (2). The component [B] is extremely excellent in compatibility with the component [A], which has the effect of preventing the above-mentioned single fibers from being fused. Separation of the silicone compound component and the non-silicone compound component occurring on the fiber surface after the drying densification step of treating the precursor fiber bundle at a high temperature in the step can be suppressed. When the [B] component in the present invention is used alone, the effect of suppressing fusion is not seen, so it is considered that the effect of combining the [A] component and the [B] component appears.

  As for the mechanism, not all of them are clarified, but I think as follows.

  As described above, as a function in the flameproofing process of the silicone compound, it was stated that it is necessary to suppress the fusion by crosslinking and covering the surface of the single fiber.

  In the case of non-silicone compounds that have been studied in combination with silicone compounds in the prior art, separation of the silicone component and non-silicone component occurs on the fiber surface after the drying densification step in which the precursor fiber bundle is treated at a high temperature in the yarn production process. Therefore, it is considered that the range covered with the crosslinked product derived from the silicone component and the thickness thereof are proportional to the amount of the silicone compound. In the treatment agent of the present invention, the silicone compound is crosslinked while retaining the component [B] during the crosslinking process, so that the coated area and the thickness can be increased. That is, it is thought that [B] component functions as a film thickness maintenance agent of a silicone crosslinked product.

  Then, the preferable aspect of a [B] component is demonstrated.

In the formula (1), R ₁ is a branched saturated hydrocarbon group having 4 to 8 carbon atoms, and A ₁ is a hydrocarbon group having 3 to 20 carbon atoms. In Formula (2), R ₂ and R ₃ are each a branched saturated hydrocarbon group having 4 to 8 carbon atoms, which may be the same or different, and A ₂ has 3 to 20 carbon atoms. It is a hydrocarbon group.

If R ₁ , R ₂ , R ₃ are linear or branched, but have 9 or more carbon atoms, compatibility with the silicone compound deteriorates and separation of components on the fiber surface is observed. Further, when the number of carbon atoms is 3 or less, the [B] component is likely to penetrate into the precursor fiber, and the effect of increasing the film thickness of the silicone compound is reduced, or the effect of suppressing fusion is reduced.

As R ₁ , R ₂ , R ₃ , it is preferable that at least one of R ₁ in formula ( ₁ ) and R ₂ , R ₃ in formula (2) is a t-butyl group or a branched octyl group. Since t-butyl groups or branched octyl groups have quaternary carbons or have a large number of branched chains, ester compounds having these groups tend to have low cohesive energy, and also have low cohesive energy. This is thought to be due to improved compatibility with the silicone compound. An ester compound having a t-butyl group or a branched octyl group in R ₁ in formula (1) and R ₂ and R ₃ in formula (2) can be esterified using neopentanoic acid or isononanoic acid as a raw material. [B] As the component, a diester obtained from neopentanoic acid and 2,4-diethyl-1,5-pentanediol, a diester obtained from neopentanoic acid and 3-methyl-1,5-pentanediol, isononanoic acid and neopentyl Examples include diester obtained from glycol, neopentanoic acid isostearyl ester, neopentanoic acid octyldodecyl ester, isononanoic acid isotridecyl ester, isononanoic acid isodecyl ester, isononanoic acid isononyl ester, and isononanoic acid ethylhexyl ester. These may be used alone or as a mixture of a plurality of components.

  The mass ratio of the [A] component and the [B] component and the amount of adhesion thereof are also important constituent elements of the present invention.

  As described above, the component [B] retains the coating range and the film thickness of the crosslinked product derived from the silicone component and assists the fusion suppressing effect. However, the component [B] itself has little fusion preventing effect. Therefore, it is essential to use the [A] component and the [B] component together, and the [A] component and the [B] component are in a mass ratio of [A]: [B] = 30: 70 to 70:30. It is necessary to include in the range.

  In the range where the ratio of the [A] component to the [B] component is less than 30:70, the content of the silicone compound is small, so that the strength of the carbon fiber bundle is insufficient. In the range where the ratio of the [A] component to the [B] component exceeds 70:30, the amount of silicone compound applied is relatively increased, resulting in an insufficient scale reduction effect. Taking into account the reduction in scale and the strength of the carbon fiber bundle, [A]: [B] is preferably in the range of 30:70 to 70:30, more preferably in the range of 40:60 to 70:30, and 50: The range of 50 to 70:30 is more preferable.

  The total adhesion amount of the [A] component and the [B] component in the treatment agent in the present invention is the acrylic fiber bundle used in the carbon fiber precursor production conditions (that is, the acrylic fiber before the treatment agent is adhered) (Bunch) It is good to use in the range of 0.05-3.0 mass parts with respect to 100 mass parts.

  In the firing step, most of the silicone compound adhering to the fiber surface becomes a scale and scatters from the fiber, so that the amount of silicon compound generated is substantially proportional to the amount of silicone compound adhering to the fiber. That is, from the viewpoint of scale suppression, it is preferable that the amount of the silicone compound attached to the precursor fiber is as small as possible. Therefore, it is preferable that the amount of treatment agent applied is as small as possible. However, when the adhesion amount is less than 0.05 parts by mass, the convergence in the process is lowered, the generation of fluff and single yarn breakage become remarkable, and the operability is lowered. In addition, the fiber surface cannot be covered with a sufficient amount of the treatment agent, so that the fusion due to the flame resistance increases and the strength of the carbon fiber bundle decreases.

  Moreover, when the application amount of the treatment agent exceeds 3.0 parts by mass, process obstacles such as winding around the roller increase.

  In the present invention, in addition to the [A] component and the [B] component, other components as described later may be added. However, in order to obtain the effects of the present invention, the [A] component and the [B] It is necessary that the component is contained in the treatment agent in an amount of 60 to 100% by mass.

  In addition, the amount of the treatment agent attached is obtained by extracting the precursor fiber bundle after the treatment agent is attached with an organic solvent such as methyl ethyl ketone, acetone, or chloroform, accurately weighing the fiber bundle mass before and after the treatment, and obtaining the difference between the masses. Can do.

  The adhesion state of the treatment agent to the fiber surface can be confirmed by observing the precursor fiber surface using a scanning electron microscope or an optical microscope. In the present invention, it is necessary that at least the [A] component and the [B] component do not separate on the fiber surface.

  As a constituent of the treatment agent of the present invention, in addition to the [A] component and the [B] component, an aromatic ester and / or a polyol as a lubricity improver for the purpose of improving the convergence of the yarn bundle and improving the lubricity. 5-30 mass% of ester can be included.

  In the present invention, the component [B] is characterized by having a branched saturated hydrocarbon group, but in general, a fiber provided with a compound having a branched saturated hydrocarbon group is inferior in lubricity and between the fiber bundle and the roller. It is known that the friction tends to be high.

  Therefore, about the lubricity improvement effect that the [A] component has been responsible for until now, part of the [B] component is replaced with a relatively low lubricity, which may cause process failures such as generation of fuzz. Conceivable.

  Therefore, the treatment agent of the present invention can contain a lubricity improver within the above range that does not impair the effects of the present invention.

  The lubricity improver is generally used as a treating agent for the carbon fiber precursor acrylic fiber, and has a lubricity improving effect and a high convergence imparting effect. As a component, known lubricants can be widely used, but aromatic esters and / or polyol esters are preferable, and fatty acid esterified products of trimellitic acid alkyl ester, bisphenol A ethylene oxide or propylene oxide adducts. And at least one compound selected from pentaerythritol fatty acid ester, trimethylolpropane fatty acid ester and dipentaerythritol fatty acid ester.

  The preferable content of the lubricity improver in the treatment agent varies depending on the surface morphology, fineness, production conditions, etc. of the precursor fiber bundle, but is as small as possible so as not to inhibit the effects of the [A] component and the [B] component. It is preferable to make it content.

  When the content is less than 5%, the remarkable effect of improving lubricity is not seen, and the occurrence of fluff may increase. When the content exceeds 30% by mass, the effect of increasing the film thickness of the component [B] And the sufficient effect of suppressing fusion cannot be exhibited.

  In addition to the above [A], [B] and the lubricity improver, the treatment agent to be applied to the precursor provided for the present invention is an emulsifier, an antioxidant, an antistatic agent, as long as the effects of the present invention are not impaired. Additives such as antifoaming agents, antiseptics, antibacterial agents and penetrants may be included.

  In particular, when water is used as a dispersion medium at the time of application to the precursor fiber bundle, the [A] component and the [B] component are low in polarity and often hardly soluble in water, so an appropriate emulsifier is used. It is preferable.

  The carbon fiber precursor acrylic fiber bundle of the present invention can be produced with a high-performance carbon fiber bundle by subjecting it to a flameproofing treatment by the method described below, followed by a carbonization treatment.

  The flameproofing treatment is usually performed at a temperature of 200 to 300 ° C. in an oxygen-containing gas atmosphere. From the viewpoint of reducing the cost and improving the performance of the obtained carbon fiber, it is preferable to make the carbon fiber precursor acrylic fiber bundle flame resistant at a temperature that is 10 ° C. to 20 ° C. lower than the temperature at which yarn breakage occurs due to the accumulation of reaction heat. From the viewpoint of improving productivity and carbon fiber productivity, the flameproofing treatment time. It is preferably 10 to 100 minutes, more preferably 30 to 60 minutes. The time for this flameproofing treatment means the total time that the yarn bundle stays in the flameproofing furnace. If this time is too short, the structural difference between the oxidized outer peripheral portion and the insufficiently oxidized inner portion of each single fiber becomes conspicuous as a whole, and the physical properties of the carbon fiber may be lowered.

  The draw ratio of the yarn bundle in the flameproofing treatment step is preferably 0.85 to 1.10, more preferably 0.88 to 1.06, and still more preferably 0.92 to 1.02. By increasing the draw ratio, the elastic modulus of the carbon fiber can be improved with the same heat treatment amount.

  Following the flameproofing process, the process proceeds to the carbonization process, but before that, a preliminary carbonization process is performed in an inert atmosphere at a temperature of 300 ° C. to 800 ° C., preferably in a nitrogen or argon atmosphere. Is also a preferred embodiment. The stretch ratio in the preliminary carbonization treatment step is preferably 0.90 to 1.25, more preferably 1.00 to 1.20, and still more preferably from the viewpoint of enhancing the performance of the obtained carbon fiber. 1.05-1.15.

  The temperature of the carbonization treatment step performed under an inert atmosphere is preferably 800 ° C to 2000 ° C. Further, the maximum temperature is appropriately selected and used according to the required characteristics of the desired carbon fiber, but if it is lower than 800 ° C., the tensile strength and elastic modulus of the resulting carbon fiber may be lowered. The drawing ratio in the carbonization step is preferably 0.95 to 1.05, more preferably 0.97 to 1.02, and particularly preferably 0.98 to 1.01, and the performance of the obtained carbon fiber. It is good from the point of raising.

  When a carbon fiber having a higher elastic modulus is desired, a graphitization treatment can be performed following the carbonization treatment. The graphitization treatment is usually performed at a temperature of 2000 to 3000 ° C. in an inert atmosphere. The maximum temperature is appropriately selected and determined according to the required characteristics of the desired carbon fiber. The draw ratio in the graphitization treatment step can be appropriately selected within a range in which quality reduction such as generation of fluff does not occur, depending on the required characteristics of the carbon fiber.

  By subjecting the obtained carbon fiber to a surface treatment, it is possible to further increase the adhesive strength with the matrix when it is made into a composite material. As the surface treatment method, a gas phase treatment or a liquid phase treatment can be adopted. However, in consideration of productivity and quality variations, an electrolytic treatment (anodic oxidation treatment) is preferably applied among the liquid phase treatments.

  As the electrolytic solution used for the electrolytic treatment, an aqueous solution containing an acid such as sulfuric acid, nitric acid and hydrochloric acid, an alkali such as sodium hydroxide, potassium hydroxide and tetraethylammonium hydroxide, or a salt thereof can be used. Particularly preferably, an aqueous solution containing ammonium ions is used. For example, an aqueous solution containing ammonium nitrate, ammonium sulfate, ammonium persulfate, ammonium chloride, ammonium bromide, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium hydrogen carbonate, ammonium carbonate, or a mixture thereof can be used as the electrolyte.

  The amount of electricity given to the carbon fiber in the electrolytic treatment varies depending on the carbon fiber used. For example, a carbon fiber having a higher degree of carbonization requires a higher amount of electricity to be supplied. In general, from the viewpoint of improving adhesive properties, the surface oxygen concentration O / of the carbon fiber measured by X-ray photoelectron spectroscopy (ESCA) is used. The amount of electricity is preferably set so that C and the surface nitrogen concentration N / C are in the range of 0.05 to 0.40 and 0.02 to 0.30, respectively.

  By satisfying these conditions, the adhesion between the carbon fiber and the matrix at the time of forming the composite material becomes an appropriate level. Therefore, the bond between the carbon fiber and the matrix is too strong, resulting in a very brittle fracture and the longitudinal tensile strength of the composite material is reduced, or the longitudinal tensile strength of the composite material is Although it is strong, it can also prevent the disadvantage that the non-longitudinal mechanical properties of the composite material do not appear because the adhesion between the carbon fiber and the matrix is too low, and it can be balanced in the fiber bundle direction and non-fiber bundle direction. Composite material properties are developed.

  The obtained carbon fiber is further subjected to sizing treatment as necessary. The sizing agent is preferably a sizing agent having good compatibility with the matrix, and is selected and used in combination with the matrix.

  The carbon fiber obtained in this way can be formed into a composite material after being prepreg, and after being formed into a preform such as a woven fabric, it is combined by a hand lay-up method, a pultrusion method, a resin transfer molding method, etc. It can also be formed into a material. The carbon fiber can be formed into a composite material by a filament winding method, chopped fiber or milled fiber, and then injection-molded.

  Composite materials using carbon fibers obtained in the present invention are used for sports applications such as golf shafts and fishing rods, aerospace applications, automotive structural member applications such as hoods and propeller shafts, and energy related applications such as flywheels and CNG tanks. It can use suitably for.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  In the examples, each characteristic was measured by the following method.

<Measurement of treatment agent adhesion>
After the precursor fiber bundle was dried at 105 ° C. for 1 hour, about 10 g was precisely weighed to prepare a sample. Using a Soxhlet extractor, the treating agent composition adhering to 200 ml of methyl ethyl ketone under reflux for 8 hours was subjected to solvent extraction. The precursor fiber bundle after extraction of the treatment agent was dried at 40 ° C. under reduced pressure of 1 kPa for 2 hours. The treatment agent adhesion amount was determined from the difference between the masses of the carbon fiber precursor fiber bundles before and after the extraction. Measurements were made at each level n = 1. The obtained treatment agent adhesion amount is normalized by dividing by the mass of the precursor fiber bundle after extraction, and converted to the number of adhesion parts of the treatment agent with respect to 100 parts by mass of the precursor fiber bundle, and then the composition of the treatment agent [A] It converted into the total number of adhesion parts of a component and [B] component, and compared between the levels.

  Regarding the level at which the second stage was applied, the first stage treatment agent adhesion amount and the total treatment agent adhesion amount were measured, and the adhesion amount of the second stage treatment agent was calculated from the difference.

<Observation of treatment agent on precursor fiber>
The precursor fiber surface was observed using a scanning electron microscope, and the presence or absence of component separation on the fiber surface was evaluated.

  Pull out the precursor fiber bundle (3,000 single fibers) from the bobbin, cut it into 20 mm lengths, and evenly divide it into four parts. Use a carbon tape so that the fiber bundle consisting of about 750 single fibers is on the surface. It fixed to the sample stand. Sampling was performed from two locations on the bobbin for each level. Platinum was vapor-deposited to a thickness of 3 nm on the sample surface by ion beam sputtering in an argon atmosphere and used for observation.

  The scanning electron microscope was S-4800 manufactured by Hitachi, Ltd., and observed at an acceleration voltage of 1 kV and an observation magnification of 2500 times. Ten images of 38 × 50 μm randomly selected were obtained under the above observation conditions, and the presence or absence of treatment component separation on the fiber surface was determined. When the hemispherical or circular deposit having a diameter of 1 μm or more is observed on the fiber surface, it was determined that separation of the treatment agent occurred. An example of an image that has been determined that no separation has occurred is shown in FIG. 1, and an example of an image that has been determined that separation has occurred is shown in FIG. In FIG. 2, a portion indicated by an arrow is a portion where a hemispherical or circular deposit having a diameter of 1 μm or more is observed on the fiber surface. If there is even one such deposit in the field of view, it is assumed that the image is a segregated image. The evaluation scale of the adherent was as follows.

○: (Number of separation-occurring images) = 0
Δ: (Number of separation-generated images) = 1 to 2
×: (Number of images generated by separation) ≧ 3.

<Number of fusions between single fibers (number of fusions)>
A carbonized carbon fiber bundle (12,000 single fibers) is cut into 3 mm lengths, dispersed in acetone, and stirred for 10 minutes, and then the total number of single fibers and the number of fusions are counted. The number of fusions was calculated and evaluated. The evaluation criteria are as follows.
○: Number of fusions (pieces / 100 pieces) ≦ 1
×: Number of fusions (pieces / 100 pieces)> 1
Measurements were made at each level n = 1.

<Measurement of strand tensile strength and tensile modulus of carbon fiber>
Carbon fiber bundles (12,000 single fibers) were impregnated by dipping in a resin having the following composition, cured for 35 minutes at a temperature of 130 ° C., and then subjected to a tensile test based on JIS R7601 (1986). = 6 strands were measured, and the strand tensile strength and tensile elastic modulus were determined as average values.
[Resin composition] (In brackets are manufacturers)
・ 3,4-epoxycyclohexylmethyl-3,4 epoxy carboxycarboxylate (ERL-4221, manufactured by Union Carbide) ・ ・ ・ 100 parts by mass ・ Boron trifluoride monoethylamine (Stella Chemifa Co., Ltd.) Manufactured) 3 parts by mass Acetone (manufactured by Wako Pure Chemical Industries, Ltd.) ... 4 parts by mass The performance was evaluated using the following criteria.
A: 5.5 GPa or more B: 5.2-5.5 GPa
Δ: 4.8 to 5.2 GPa
X: 4.8 GPa or less.

<Evaluation of the amount of silicon scattered from the silicone compound in the firing process>
The amount of silicon scattered from the silicone compound in the firing process is determined by measuring the carbon content of the carbon fiber precursor acrylic fiber bundle and the carbon fiber bundle obtained by firing the fiber bundle using a fluorescent X-ray analyzer, and firing the difference. The amount of silicon scattered in the process was calculated and used as an evaluation index.

(Silicon scattering amount) = silicon content of precursor fiber bundle−silicon content of carbon fiber bundle [g / kg]
As the fluorescent X-ray analyzer, a fluorescent X-ray apparatus VENUS200 manufactured by Nippon Philips Co., Ltd. was used. The primary X-ray source was Sc, and the measurement conditions were a reduced pressure and an atmospheric pressure of 4 to 8 Pa, a temperature of 37 ° C., and a measurement time of 25 seconds. Precursor fibers and carbon fibers, which are measurement samples, were uniformly wound around a Teflon (registered trademark) plate having a length of 30 mm, a width of 30 mm, and a thickness of 2 mm for use in measurement. At this time, the precursor fiber was sampled to a length of 60 cm, and the carbon fiber was sampled to a length of 1 m. From the obtained precursor fiber bundle and the fluorescent X-ray intensity of the silicon element in the carbon fiber bundle, a calibration curve was used to determine the silicon content relative to the fiber mass for each fiber bundle. The number of measurements was n = 10, and the average value thereof was used for evaluation as follows.
○: Silicon scattering amount 0-0.9 g / kg
Δ: Amount of silicon scattered 0.9-1.8 g / kg
×: Silicon scattering amount 1.8 g / kg or more.

  The components used in the present invention are as follows.

<[A] component>
A1: 1,2 secondary side chain amino-modified silicone (trade name “KF-8002”, manufactured by Shin-Etsu Chemical Co., Ltd.)
A2: Primary side chain amino-modified silicone (“KF-864”, manufactured by Shin-Etsu Chemical Co., Ltd.)
A3: Both-terminal amino-modified silicone (“KF-8008”, manufactured by Shin-Etsu Chemical Co., Ltd.)
A4: Polyether-modified silicone (“KF-615”, manufactured by Shin-Etsu Chemical Co., Ltd.).

<[B] component (including component to be compared with B component)>
B1: Neopentanoic acid isostearyl ester ("Neolite (registered trademark) 180P", manufactured by Higher Alcohol Industry Co., Ltd.)
B2: Neopentanoic acid octyldodecyl ester ("Neolite (registered trademark) 200P", manufactured by Higher Alcohol Industry Co., Ltd.)
B3: ethyl hexyl isononanoate (“ES108109”, manufactured by Higher Alcohol Industry Co., Ltd.)
B4: Isononanoic acid isononyl ester (“KAK 99”, manufactured by Higher Alcohol Industry Co., Ltd.)
B5: Isononanoic acid isodecyl ester (“KAK 109”, manufactured by Higher Alcohol Industry Co., Ltd.)
B6: Isotridecyl isononanoic acid ester (“KAK 139”, manufactured by Higher Alcohol Industry Co., Ltd.)
B′7: Neodecanoic acid octyldodecyl ester (“Neolite (registered trademark) 2000”, manufactured by Higher Alcohol Industry Co., Ltd.) (the carbon number of R ₁ is not included in the range of formula (1). ] Not applicable)
B8: Diester obtained from neopentanoic acid and 2,4-diethyl-1,5-pentanediol (“Neosole (registered trademark) -DE”, manufactured by Nippon Seika Co., Ltd.)
B9: Diester obtained from neopentanoic acid and 3-methyl-1,5-pentanediol (“Neosolue®-MP”, manufactured by Nippon Seika Co., Ltd.)
B10: Diester obtained from isononanoic acid and neopentyl glycol (“NPDIN”, manufactured by Higher Alcohol Industry Co., Ltd.).

<Other ingredients (emulsifier)>
Block polyether type surfactant (PEG / PPG-160 / 30 copolymer, “Adekapluronic (registered trademark) F-68”, manufactured by ADEKA Corporation)
In addition, regarding the said component used, the content of [A] component was put together in Table 1, and the other component was put together in Table 2.

<Adjustment of treatment agent dispersion>
Each processing agent was adjusted with the composition described in Table 3, and used for production of carbon fiber precursor fiber bundles.

  The treatment agent is prepared by mixing each component at the blending ratio shown in Table 3, and adding the ion-exchange water to the treatment agent so that the concentration in the aqueous dispersion becomes 20% by mass. And emulsified by stirring. In this state, since the particle diameter of the emulsified processing agent is about 1 to 2 μm, it was further dispersed to a particle diameter of 0.2 μm or less by a high-pressure homogenizer to obtain a processing agent dispersion stock solution. Ion exchanged water was further added to this treating agent dispersion stock solution to adjust the concentration as shown in Table 3 to obtain a treating agent dispersion, which was used in the following steps.

  As shown in Table 4, for the treatment agent used for the second stage application, the treatment dispersion was not adjusted, and the components [A] and [B] were used alone or in combination.

<Method for producing precursor fiber bundle>
(Examples 1-14, Comparative Examples 1-8)
A copolymer obtained by copolymerizing 99.5 mol% of acrylonitrile and 0.5 mol% of itaconic acid was polymerized by a solution polymerization method using dimethyl sulfoxide as a solvent to obtain a spinning solution having a concentration of 22% by mass. After the polymerization, ammonia gas was blown into the spinning solution until the pH reached 8.5 to neutralize itaconic acid and introduce ammonium groups into the components, thereby improving the hydrophilicity of the spinning solution. The obtained spinning solution was discharged into the air once using a spinneret having a diameter of 0.15 mm and a hole number of 3000 at a temperature of 40 ° C., passed through a space of a distance of about 4 mm, and then a temperature of 10 ° C. The solution was coagulated by dry and wet spinning introduced into a coagulation bath composed of a 40% by mass dimethyl sulfoxide aqueous solution controlled to 1%. The obtained coagulated yarn was washed with water and then stretched 2.8 times in warm water at a temperature of 70 ° C. Furthermore, the treatment agent is applied to the fiber bundle by a dip-nip method by passing through a bath filled with the treatment agent dispersion liquid prepared as described above, and the contact time is 40 seconds using a heating roller at a temperature of 180 ° C. A drying treatment was performed.

  The obtained dried yarn was drawn in 0.4 MPa pressurized water vapor at a secondary draw ratio of 5 times to obtain a precursor fiber bundle having a single fiber fineness of 1 dtex and a single fiber number of 3000.

(Examples 15 to 17, Comparative Examples 9 to 11)
In the same manner as in Example 1, the precursor fibers coagulated, washed with water and stretched are further passed through a bath filled with the treatment agent dispersion prepared above, so that the treatment agent is dip-niped into the fiber bundle. Then, the first-stage application process was performed. Subsequently, a drying process with a contact time of 40 seconds was performed using a heating roller having a temperature of 180 ° C.

  The obtained dried yarn was stretched in pressurized water vapor of 0.4 MPa with a secondary stretching ratio of 5 times. By applying a treatment agent having a blending ratio shown in Table 4 to the precursor fiber that has been subjected to secondary stretching by the touch roll method, the precursor fiber having a single fiber fineness of 1 dtex and a single fiber number of 3000 is provided. Got a bunch.

<Method for producing carbon fiber bundle>
The resulting precursor fiber bundle was combined into four yarns to make the number of single fibers 12,000, and then heated in air at a temperature of 240 to 280 ° C. to convert it into a flameproof fiber bundle. The flameproofing treatment time was 40 minutes, and the stretch ratio in the flameproofing treatment process was 1.00.

  Further, the flame-resistant fiber bundle was heated in a nitrogen atmosphere at a temperature of 300 to 800 ° C. to be pre-carbonized, and then heated in a nitrogen atmosphere at a maximum temperature of 1300 ° C. for carbonization. The stretch ratio in the preliminary carbonization treatment step was 1.10, and the stretch ratio in the carbonization treatment step was 0.97. Furthermore, the fiber bundle obtained by the carbonization treatment was anodized with an electric quantity of 10 coulomb / g-CF in a sulfuric acid aqueous solution to obtain a carbon fiber bundle.

  The performance of the produced precursor fiber bundle and carbon fiber bundle was evaluated by the above-described methods. The evaluation results are collectively shown in Tables 3 and 4. In the following, comparison between each evaluation level is performed.

<Comparison of Examples 1-9 and Comparative Examples 1-3>
A comparative study was performed on the types of the component [B] contained in the treatment agent.

  Comparative Example 1 is an example of a precursor fiber bundle in which an optimal amount of a conventionally known silicone-based treatment agent containing no [B] component is attached in consideration of the strength and operability of carbon fiber. This is a comparative reference in the invention. Although high-strength carbon fibers were obtained, a large amount of silicon was scattered, scales were generated, and the stability of the firing process was not at an acceptable level.

  As in Comparative Example 2, when the adhesion amount of the treatment agent used in Comparative Example 1 was halved, the silicon scattering amount was halved, but the number of fusions increased, and a significant decrease in strength of the carbon fiber was observed.

  In Examples 1-9, although the adhesion amount of [A] component is equivalent to Comparative Example 2 and the amount of silicon scattering is halved, no decrease in strength of the carbon fiber is observed. Although some fluff was observed in the carbon fibers within a range not causing any problems in 2 to 4, Example 7 and Example 8, carbon fibers having good quality and quality could be obtained.

  That is, in Examples 1 to 9 of the present invention, the trade-off relationship between the strength of the carbon fiber and the silicon scattering amount found in Comparative Example 1 and Comparative Example 2 is eliminated, and the scattering of the silicon compound is halved. Moreover, it was confirmed that it was possible to suppress a decrease in the mechanical strength of the carbon fiber. In any of Examples 1 to 9, separation of the treatment agent component on the precursor fiber surface was not observed.

In Comparative Example 3, since R ₁ in Formula (1) has 9 carbon atoms, it is a level using Compound B′7 that does not correspond to the [B] component of the present invention. Separation from the silicone compound occurred, the number of fusions was large, and the strength of the carbon fibers was not satisfactory.

<Comparison of Example 1 and Examples 10-12>
Then, the comparative examination regarding the kind of [A] component used for the processing agent of this invention was performed.

  Even if the type of the modified silicone was changed, no significant decrease in strength was observed, and carbon fibers having good quality and quality could be obtained at any level.

  No separation of the treatment agent component on the precursor fiber surface was observed. Moreover, the silicon scattering amount was also good.

  In Example 12, there was no problem, but there was a single fiber winding and fluffing in the firing process.

<Comparison of Example 13, Example 14, and Comparative Examples 4-6>
A comparative study was performed on the ratio of the [A] component and the [B] component.

  In the comparative example 4 using the processing agent which does not contain the [A] component, the winding to the roller frequently occurred in the firing step, and the precursor fiber bundle could not be obtained.

  In Example 13, although some fluff was observed in the carbon fiber within a range not causing a problem, a result satisfying both the strength of the carbon fiber and the silicon scattering amount was obtained. No separation of the treating agent component on the fiber surface was observed.

  Furthermore, in Comparative Example 5 in which the amount of the [A] component was reduced and the amount of the [B] component was increased, separation of the treatment agent component on the fiber surface was not observed, but the number of fusions was large and the strength of the carbon fiber was satisfactory. It was not a level.

  In Example 14, no decrease in strength of the carbon fiber was observed. Although the silicon scattering amount was somewhat large, it was within an acceptable range. Separation of the treating agent component on the fiber surface was not observed.

  Further, in Comparative Example 6 in which the amount of the [A] component was increased and the amount of the [B] component was decreased, a decrease in the strength of the carbon fiber was not observed, but a large amount of silicon was scattered, a scale was generated, and the stability of the firing process was As in Comparative Example 1, it was not an acceptable level.

<Comparison of Example 1, Comparative Example 7, and Comparative Example 8>
A comparative study was conducted on the amount of treatment agent deposited.

  In Comparative Example 7 in which the treatment agent had a high adhesion amount, the number of fusions was small, but the winding around the roller in the firing process increased, and the operability was not at a satisfactory level. Moreover, the strength of the carbon fiber was low and the amount of silicon scattering was large.

  In Comparative Example 8 in which the treatment agent was used in a low adhesion amount, winding around the roller frequently occurred in the firing step, and a precursor fiber bundle could not be obtained.

<Comparison of Examples 1, 15-17, and Comparative Examples 9-11>
Subsequently, a comparative study was performed on the method for applying the treatment agent of the present invention. In Examples 15 to 17 in which the two-stage application was performed, no significant strength reduction was observed as in Example 1, and carbon fibers having good quality and quality could be obtained at any level. Also, there was little gum-up on the drying roller, and the process passability was good. On the other hand, in Comparative Example 9 using the treatment agent that did not contain the [A] component although two-stage application was performed, Winding of the wire frequently occurred, and a precursor fiber bundle could not be obtained. Moreover, also in Comparative Examples 10-11 with a low ratio of [A] component, the intensity | strength of carbon fiber fell significantly and was not satisfactory.

Claims (7)

An acrylic fiber bundle having a treatment agent attached to the surface, wherein the treatment agent contains 60 to 100% by mass of the following [A] component and the following [B] component in the treatment agent, and the following in the treatment agent: The total adhesion amount of the [A] component and the following [B] component is 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the acrylic fiber bundle before the treatment agent is adhered, and the Carbon fiber precursor acrylic characterized in that the mass ratio of the following [A] component and the following [B] component in the treatment agent is in the range of [A]: [B] = 30: 70 to 70:30 Fiber bundle.
[A] Modified silicone [B] Compound represented by the following formula (1) and / or formula (2)
(In Formula (1), R ₁ is a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and A ₁ is a monovalent hydrocarbon group having 3 to 20 carbon atoms.)
(In Formula (2), R ₂ and R ₃ are each a monovalent branched saturated hydrocarbon group having 4 to 8 carbon atoms, and may be the same or different. A ₂ has 3 to 20 carbon atoms. Divalent hydrocarbon group.) The carbon fiber precursor acrylic fiber bundle according to claim 1, wherein the component (A) is amino-modified silicone. At least one of R ₁ in Formula ( ₁ ) and R ₂ and R ₃ in Formula (2) of the [A] component and / or [B] component contained in the treating agent is a t-butyl group or a branched octyl group. The carbon fiber precursor acrylic fiber bundle according to claim 1 or 2, which is a group. [B] component is a diester obtained from neopentanoic acid and 2,4-diethyl-1,5-pentanediol, a diester obtained from neopentanoic acid and 3-methyl-1,5-pentanediol, isononanoic acid and neopentyl glycol At least one selected from the group consisting of diester, neopentanoic acid isostearyl ester, neopentanoic acid octyldodecyl ester, isononanoic acid isotridecyl ester, isononanoic acid isodecyl ester, isononanoic acid isononyl ester, isononanoic acid ethylhexyl ester The carbon fiber precursor acrylic fiber bundle according to any one of claims 1 to 3, which is one compound. It is a manufacturing method of the carbon fiber precursor acrylic fiber bundle of Claims 1-4, Comprising: The acrylic fiber bundle before providing the said processing agent is in the bath filled with the dispersion liquid of this processing agent. The manufacturing method of the carbon fiber precursor acrylic fiber bundle which has the process of making it dry process after giving a processing agent through it. The method for producing a carbon fiber precursor acrylic fiber bundle according to claim 5, further comprising a step of applying a treatment agent after the drying treatment. The carbon fiber precursor acrylic fiber bundle according to any one of claims 1 to 4 or the carbon fiber precursor acrylic fiber bundle produced by the method according to claim 5 or 6 in an oxygen-containing atmosphere. A method for producing a carbon fiber bundle, characterized by being flame resistant at 0 ° C. and then carbonized.