WO2002095100A1

WO2002095100A1 - Flame-resistant fiber material, carbon fiber material, graphite fiber material and method for production thereof

Info

Publication number: WO2002095100A1
Application number: PCT/JP2002/004994
Authority: WO
Inventors: Isao Nakayama; Tetsunori Higuchi; Masafumi Ise; Tomihiro Ishida; Koichi Yamaoka
Original assignee: Toray Industries, Inc.
Priority date: 2001-05-24
Filing date: 2002-05-23
Publication date: 2002-11-28

Abstract

A flame-resistant fiber material which has an average oxygen concentration in the interior of the fiber of 0.07 to 0.17 as measured by the elemental analysis-oxygen analysis method, an average survival rate for nitrile groups of 0 to 40 % as measured by the infrared spectroscopy, and a ratio (O1/O2) of an average oxygen concentration (O1) of the surface of the fiber to an average oxygen concentration (O2) of a frozen and pulverized fiber, as measured by the X-ray photoelectron spectroscopy, of 1.8 to 4.0; a method for producing the flame-resistant fiber material which comprises subjecting an acrylic fiber material to a treatment for enhancing flame resistance in the presence of one or more compounds of an organic compound except an amine at 180 to 300 ˚C, a fluorine-containing compound, a siloxane, a nitrate, and a nitride; and a method for producing a carbon fiber material which comprises subjecting the above flame-resistant fiber to a carbonization treatment at a temperature not lower than 300˚C and lower than 2000 ˚C in an inert atmosphere.

Description

Specification

Flame-resistant fiber material, carbon fiber material, graphite fiber material and their manufacturing method

Technical field

The present invention relates to an oxidized fiber material, a carbon fiber material, a graphite fiber material, and a method for producing the same. More specifically, the present invention relates to a high-performance flame-resistant fiber material, a carbon fiber material, and a graphite fiber material, and further relates to a stable and highly efficient method for producing a flame-resistant fiber material, a carbon fiber material, and a graphite fiber material.

Background art

Flame resistant fibers are widely used in applications requiring heat resistance because of their excellent flame retardancy. As a form, it is often used in the form of a fabric, and it is used as a spatter sheet to protect the human body from high-heat iron powder or welding sparks scattered during welding work, etc., and also as a flameproof insulation material for aircraft etc. Used.

In addition, carbon fibers obtained by heat-treating oxidized fibers at high temperatures in an inert gas atmosphere are used in various applications, such as aircraft and rockets, due to their mechanical, chemical and electrical properties and lightness. It is widely used for space aviation materials, tennis rackets, golf shafts, fishing rods and other sporting goods, and is also about to be used in transportation equipment such as ships and automobiles.

In these applications, carbon fibers are often used in combination with various resins as reinforcing fibers of fiber-reinforced composite materials. Therefore, the strength of carbon fiber in the fiber direction In addition, there has been a demand for improvement in strength in non-fiber directions such as adhesiveness to resin. Therefore, attempts have been made to improve the adhesiveness between the carbon fiber and the resin, for example, by electrolytically treating the surface of the carbon fiber. Because of the cost, the effect was insufficient, and it was difficult to achieve both fiber-direction strength and non-fiber direction strength.

Also, carbon fiber fabrics are used for secondary batteries, such as anodes of sodium-sulfur batteries used for power storage, etc., utilizing their electrical properties. In such applications, properties such as electrical conductivity and chemical stability are required.

While such high performance is required, with the expansion of applications, it is necessary to improve productivity and provide flame-retardant fiber, carbon fiber, flame-retardant fiber cloth and carbon fiber cloth at low cost. Is desired.

Generally, as the flame-resistant fiber, an acryl-based flame-resistant fiber obtained by heat treatment using an acrylic fiber as a precursor fiber is known. The flame-resistant treatment for producing such an acryl-based flame-resistant fiber is performed by oxidizing a polymer chain of the acrylic fiber and cyclizing a nitrile group bonded to the polymer chain. By promoting the oxidation and cyclization in this way, the heat resistance of the fiber is increased, and a flame-resistant fiber that can be used in flame-retardant applications can be obtained. The purpose of the oxidation treatment is to convert the fiber into a fiber having a stable structure that can withstand heat treatment at a high temperature in the carbonization process.

Such a flame-proofing reaction is an exothermic reaction accompanied by a large amount of heat generated by the oxidation and cyclization reaction of the polymer chain, and a large amount of heat is required to increase the heating temperature to increase the speed of the flame-proofing treatment and to increase the productivity. When the acrylic fiber was supplied to the flame-proofing process, the amount of heat generated in the fiber became excessive, and there was a problem that the heat storage phenomenon caused the reaction to run away.

To cope with this problem, it has been considered to perform the oxidation treatment only in an inert atmosphere, which generates less heat than the oxidation treatment in an oxidizing atmosphere. However, such a treatment alone slows down the rate of the cyclization reaction, and the strength of the obtained oxidized fiber is not sufficient. As a result, the strength characteristics of the obtained carbon fiber are deteriorated. there were.

In order to increase the efficiency of the flame-resistant treatment, Japanese Patent Publication No. Sho 53-22557, Japanese Patent Publication No. 58-2144535, Japanese Patent Publication No. 58-17464 In the gazette, heat treatment in the air After the treatment, a technique has been proposed in which a flame treatment is performed by heat treatment in an inert atmosphere with an adjusted oxygen concentration, and then the carbonization treatment is performed. As a result, the heat generated in the initial stage was large, and it was virtually impossible to treat thick yarns and large amounts of yarns with high efficiency.

Japanese Patent Application Laid-Open No. 7-292526 discloses that acryl-based fibers are heat-treated in an inert atmosphere having an oxygen concentration of 0.01 to 3% by volume, and then heat-treated in an oxidizing atmosphere. Although a method for producing a carbon fiber to be treated is disclosed, such a method has a drawback that the efficiency of the oxidation treatment is greatly reduced because the cyclization rate is reduced. Further, JP-A-2-300324 and JP-A-2-300325 disclose that a fiber is subjected to a flame-resistant treatment under normal pressure or reduced pressure, and then further subjected to flame-resistance under pressure. Although the technology for processing is disclosed, there is a problem that the efficiency of the anti-oxidation treatment is insufficient and the apparatus becomes large in size.

Further, Japanese Patent Application Laid-Open No. 59-125139 discloses a technique for performing a flame-resistant reaction treatment in a liquid phase. However, with such a method, if the number of filaments becomes 20 or more than 0000, There was a problem that the reaction proceeded unevenly and a large number of fusions occurred between the single fibers of the oxidized fiber, resulting in a decrease in strength.

In addition, the following problems occur when manufacturing the flame-resistant fiber fabric and the carbon fiber fabric.

Generally, an oxidized fiber fabric is manufactured by directly processing an oxidized fiber into a fabric. Further, the carbon fiber cloth is manufactured by directly processing the carbon fiber into the cloth or by carbonizing the flame-resistant fiber cloth.

However, in general, the strength and elongation of acrylic fibers are high, but the strength and elongation of flame-resistant fibers are reduced due to the formation of cyclized structures accompanied by chemical reactions at high temperatures. Further, carbon fibers have very high strength, while brittle fibers have extremely low elongation. For this reason, there has been a problem that, when processing the flame-resistant fiber or the carbon fiber into the fabric, a process trouble such as thread breakage is more likely to occur than when the acryl-based fiber is processed into the fabric.

In response to such a problem, for example, Japanese Patent Application Laid-Open No. 7-32638-4 discloses that an acrylic fiber, which is a precursor fiber of a flame-resistant fiber, is made into a nonwoven fabric, and then heated and oxidized to perform a flame-resistance treatment. The invention discloses an invention in which a carbon fiber nonwoven fabric is obtained by applying a high temperature nonwoven fabric to a nonwoven fabric by applying a high temperature treatment under an inert atmosphere. Acrylic fibers have both high strength and high elongation, so that nonwoven fabrics can be produced more easily than flame-resistant fibers or carbon fibers. However, nonwoven fabric acrylic fibers are not easily flame-resistant due to their bulkiness. In other words, the oxidation treatment is an exothermic reaction, and a heat removal operation is indispensable. However, if the acrylic fiber has a high yarn density such as a nonwoven fabric, heat is easily stored in the oxidation treatment, and the heat removal is performed. Heat becomes difficult. Therefore, it is necessary to treat at a low ambient temperature to prevent runaway, and it takes a long time for the flameproofing treatment of the nonwoven fabric, so that the productivity was extremely poor industrially.

Disclosure of the invention

An object of the present invention is to provide a high-productivity, high-performance flame-resistant fiber material, carbon fiber material, and graphite fiber material in view of the above problems. The flame-resistant fiber material, the carbon fiber material, and the black forceps fiber material referred to in the present invention include a flame-resistant fiber bundle, a carbon fiber bundle and a graphite fiber bundle in which a plurality of single fibers are bundled, and a plurality of single fibers. Includes flame-resistant fiber fabric, carbon fiber fabric and graphite fiber fabric processed into a shape.

In order to achieve the object of the present invention, the flame-resistant fiber material of the present invention has the following configuration. That is, the average oxygen concentration in the fiber measured by elemental analysis and oxygen analysis (o

ZC) is 0.07 to 0.17. A carbon fiber material can be obtained at a high yield by carbonizing such a flame-resistant fiber material. The carbon fiber material of the present invention is obtained by measuring the cross section of a single fiber using a field emission electron microscope by electron energy loss spectroscopy and measuring the outermost surface value A1 of 7T * / σ * and the highest value A inside the single fiber. The carbon fiber material having a ratio A 1 ZA 2 of 0.83 to 0.94.

Further, the above-described flameproofed fiber material of the present invention is suitably manufactured by the following manufacturing method. That is, the acrylic fiber material contains one or more compounds selected from organic compounds other than amine compounds, fluorine compounds, siloxanes, nitrates, and nitrites. In the presence, it is subjected to a flameproofing treatment at 180 to 300 ° C. In the present invention, such an acryl-based fiber material includes an acryl-based fiber bundle and an acryl-based fiber cloth.

Further, the above-mentioned carbon fiber material of the present invention is suitably produced by carbonizing the oxidized fiber material in an inert atmosphere at a temperature of at least 300 and less than 2,000. Further, the graphite fiber material of the present invention is suitably produced by heat-treating the carbon fiber material in an inert atmosphere at a temperature of not less than 2,000 ° C. and not more than 3,000 ° C.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be described in more detail.

The present inventors can obtain a high-performance flame-resistant fiber material with a high efficiency by setting the oxygen concentration in the fiber of the flame-resistant fiber to a specific range, and convert the carbon fiber material from the flame-resistant fiber material. It has been found that the efficiency in manufacturing is also improved.

Also, by using fibers having a specific double structure with different oxygen contents on the surface and inside of the oxidized fiber, the productivity of the carbon fiber material produced from the oxidized fiber material is dramatically improved. Was found. Furthermore, it has been found that such an oxidized fiber makes it possible to provide a carbon fiber having a specific double structure. Since the carbon fiber has a double structure in which the crystallinity between the surface and the inside is different, it is possible to improve the adhesiveness between the carbon fiber and the resin while maintaining the strength of the carbon fiber itself.

Further, even when the acrylic fiber material which is the precursor fiber is a high-density fiber bundle in which a large number of single fibers are bundled, or when the acryl-based fiber bundle is subjected to flame-resistant treatment in a dense state, This is a method for producing a flame-resistant fiber material having a high carbon content, a structure having a small number of unclosed rings, and a high tensile strength.

In other words, the oxidized fiber of the present invention has an average in-fiber measured by elemental analysis and oxygen analysis. It is important that (O / C) is between 0.07 and 0.17. More preferably, it is from 0.08 to 0.16, and still more preferably from 0.1 to: 1.5. The average oxygen concentration in the fiber (O / C) measured by elemental analysis and oxygen analysis is an index of the degree of oxidation progress. If the average oxygen concentration in the fiber is less than 0.07, the heat resistance is low. Subsequent carbonization may not be possible, and if it exceeds 0.17, the yield after the subsequent carbonization may be reduced because the oxygen content is too large.

Here, the average oxygen concentration (O / C) in the fiber measured by elemental analysis and oxygen analysis is the ratio OZC between the carbon content C measured by elemental analysis and the oxygen content 0 measured by oxygen analysis.

Elemental analysis is a method in which an organic compound is heated to a high temperature to decompose it, and its constituent elements are converted into simple inorganic compounds, respectively, and led to a differential thermal conductivity meter for quantification. The calculation of the content of each element can also be performed by using a paddle that can be automatically performed by a computer. For example, the devices and the like described in the embodiments can be used.

Oxygen analysis is a method in which organic compounds are decomposed by heating to high temperature, all oxygen is converted to carbon monoxide, and the resulting quantity is led to a non-dispersive spectrometer for determination. For example, the devices and the like described in the embodiments can be used.

Incidentally, the acrylic oxidized fiber has a cyclized structure in which a nitrile group is closed. However, the oxidized fiber material of the present invention has an average residual rate of nitrile groups in the fiber, that is, nitrile which is not involved in cyclization. The residual ratio of the group is preferably 0 to 40%, more preferably 0 to 35%, and still more preferably 0 to 30%. When the average residual ratio of nitrile groups in the fiber exceeds 40%, the yield after the subsequent carbonization treatment may decrease. Here, the nitrile group residual ratio can be determined from the absorbance ratio of the nitrile group before and after the heat treatment using infrared spectroscopy, for example, by the method described below.

Further, the oxidized fiber of the present invention has a ratio of the average oxygen concentration O 1 of the fiber surface measured by X-ray photoelectron spectroscopy to the average oxygen concentration 〇 2 of the freeze-ground fiber measured by X-ray photoelectron spectroscopy. It is important that 02 be between 1.8 and 4.0. Such O 1 ZO 2 is more preferably from 1.9 to 3.5, even more preferably from 2.0 to 3.2.

When the ratio of the average oxygen concentration 〇 1 ZO 2 is less than 1.8, the double structure is low. Therefore, the yield after carbonization treatment is low, and when 〇1Z〇2 exceeds 4.4.0, the physical properties are degraded because the double structure is too strong.

Here, the average oxygen concentration O 2 of the freeze-ground fiber measured by X-ray photoelectron spectroscopy substantially represents the internal oxygen concentration of the oxidized fiber. The average oxygen concentration 〇2 of such a freeze-ground fiber is preferably from 0.3 to 0.10, more preferably from 0.03 to 0.09, more preferably from 0.03 to 0.09. More preferably, it is 0.7. If the average oxygen concentration of the frozen and ground fiber is less than 0.03, the heat resistance becomes low and the carbonization cannot be continued. If it exceeds 0.10, the yield after the subsequent carbonization decreases. Thus, by having a double structure in which the oxygen concentration on the fiber surface is higher than the oxygen concentration inside the fiber, the heat resistance is improved and the yield after the subsequent carbonization treatment is improved. Further, the present invention provides a carbon fiber having a double structure described later.

Further, the oxidized fiber of the present invention has a single fiber tensile strength of preferably 250 to 450 MPa, more preferably 300 to 450 MPa, and still more preferably 350 to 450 MPa. It is good.

Density of oxidized fiber of the present invention in the oxidization process developing, 1. 1 8~ 1. 3 5 g Zcm 3, preferably 1.2 0 - 1. and even better at ³ 5 gZ cm 3. The density of the oxidized fiber after completion of the oxidization is preferably 1.35 to 1.50 gZ cm ³ . Density of oxidized fiber is an index of flame resistant progress, if the density of oxidized fiber is less than 1. ³ 5 g / cm 3, ing impossible carbonizing followed for flame resistance is not sufficient If it exceeds 1.50 g / cm ³ , flame resistance may be too deep and physical properties may be reduced. In addition, even fibers having a density of less than 1.35 gZ cm ³ can be used for applications such as fire protection clothing, heat insulating materials, and brake pads.

In the present invention, the precursor fiber used as a raw material such as the oxidized fiber and the carbon fiber is preferably made of an acryl-based copolymer. Such an acrylic copolymer is preferably a copolymer obtained by copolymerizing 85% by mole or more, more preferably 90% by mole or more, and still more preferably 94% by mole or more of acrylonitrile with a so-called flame retardant component. Are preferred. The method for polymerizing such a copolymer is not particularly limited, but a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, or the like can be applied.

As the flame retardant component, a compound containing a vinyl group is preferable. In particular, Acrylic acid, methacrylic acid, itaconic acid, and the like, more preferably, a copolymer comprising an ammonium salt of acrylic acid, methacrylic acid, or itaconic acid in which a part or all of these are neutralized with ammonia, are exemplified. In addition, metal salts of aryl sulfonic acid, metal salts of methallyl sulfonic acid, acrylic acid esters, methacrylic acid ester acrylamide, and the like can also be copolymerized.

As the spinning solution, any of an organic solvent and an inorganic solvent can be used as a solvent together with the above-mentioned acrylic copolymer, but it is preferable to use an organic solvent, specifically, dimethyl sulfoxide, dimethylformamide, Dimethyl acetate amide and the like.

The spinning method is not particularly limited, but a wet spinning method, a dry-wet spinning method, a dry spinning method, a melt spinning method, and other known methods can be used. Preferably, a method of spinning a spinning solution comprising the acryl-based copolymer and a solvent as described above from a die by a wet spinning method or a dry-wet spinning method, and introducing the spinning solution into a coagulation bath to coagulate the fibers can be used.

The solidification rate and the stretching method can be appropriately set according to the intended use of the oxidized fiber material and the carbon fiber material.

In the present invention, the coagulation bath may contain a so-called coagulation-promoting component in addition to a solvent such as dimethyl sulfoxide, dimethylformamide, and dimethylacetamide. As the coagulation accelerating component, those which do not dissolve the acrylic copolymer and are compatible with the solvent used for the spinning dope can be preferably used. As such a coagulation promoting component, specifically, it is preferable to use water.

The temperature of the coagulation bath and the amount of the coagulation accelerating component can be appropriately set in accordance with the intended use of the oxidized fiber material and carbon fiber material. The coagulation rate can be controlled by adjusting the temperature of the coagulation bath and the amount of the coagulation accelerating component.

After being introduced into a coagulation bath to coagulate the yarn, an acrylic fiber can be obtained through water washing, stretching, drying, oiling and the like. Here, the coagulated yarn may be drawn directly without being washed with water or drawn in a bath after the solvent is removed by washing with water. Also, after applying the oil agent, it can be further stretched by steam.

In such a bath, stretching is usually performed in a single or multiple stretching baths controlled at 30 to 98 ° C. Can be done at Bath liquid of the washing bath and stretching bath, applying the content of the solvent are use in the spinning solution described above is, after it is preferred _£ bath stretching does not exceed the content of the solvent in the coagulation bath, an oil on yarn In this case, it is preferable to apply an oil agent made of silicone or the like. The silicone oil is preferably a modified silicone, and more preferably contains an amino-modified silicone having high heat resistance.

In order to reduce the production cost by increasing the density of the yarn, the number of filaments of the acryl-based fiber bundle is preferably from 1,000 to 3,000,000, more preferably 1,200,000. ~ 3,000,000, more preferably 24,000 ~ 2,500,000, particularly preferably 36,000 ~ 2,000, 000, Most preferably, it is 48,000 to 2,000,000.

The number of filaments in the acrylic fiber bundle is preferably at least 1,000 from the viewpoint of high productivity. However, if it exceeds 3,000, 000, the inside may not be uniformly flame-proofed. .

The single fiber fineness of the acrylic fiber is preferably 0.56 to 3.O dtex, more preferably 0.8 to 2.2 dte X, and still more preferably 1.0 to 1.7 dtex. .

The single fiber fineness of the acryl-based fiber is preferably 0.56 dtex or more from the viewpoint of high productivity. However, if it exceeds 3.0 dtex, it may not be possible to perform the flame-resistant treatment to the inside of the single fiber. '

In the present invention, the acryl-based fiber material can be processed into a fabric and subjected to a flame-proofing treatment and a carbonizing treatment by a method described later.

In other words, the flame-resistant fiber fabric and the carbon fiber fabric of the present invention may be formed by fabricating the flame-resistant fiber bundle and the carbon fiber bundle obtained by the method described below, or by converting the acryl-based fiber that is the precursor fiber into a fabric. Flameproofing treatment and carbonization treatment can also be performed by the methods described below. The method of fabricating acrylic fiber and performing the flame-proofing treatment and carbonization treatment has fewer process troubles such as yarn breakage than the method of fabricating the flame-resistant fiber material or carbon fiber material which is brittle fiber. Is preferred.

Here, the fabric is mainly a woven fabric, a knitted fabric, or a nonwoven fabric, but also includes a three-dimensional woven fabric, a multiaxially knitted fabric, a lace, a braid, a net, and the like. Among them, woven and non-woven fabrics are strong and cost It is used for various purposes because of its excellent surface.

Here, the woven fabric may be one in which the warp and the weft run at right angles to each other, or in some cases, the weft runs obliquely and woven at an arbitrary angle. Examples of the weave organization include plain weave, twill weave, and satin weave. The woven fabric can be woven by using a shuttle loom, a rapier loom, an air jet loom, a jet mill, or the like. Woven fabrics are preferred because they have excellent multidirectional strength. Therefore, the flame-retardant fiber fabric of the present invention is used for various flame-resisting and fire-preventing applications, and is preferably used as a brake pad, for example. Further, carbon fiber woven fabric can be preferably used as a base material of various fiber reinforced composite materials. For example, it can be used as a reinforcing fiber base material for pre-predator, or it can be directly impregnated into a reinforcing fiber material and then heat-cured, that is, a hand lay-up method, a filament, a winding method, a pulling method. It can also be used as a reinforcing fiber base for resin, injection and molding methods, and resin, transfer and molding methods.

The knitted fabric is a fabric knitted using a braid and has a loop such as a warp knit or a weft knit.

Non-woven fabric is literally “non-woven fabric” and refers to a sheet-like material in which fibers are bonded together in various ways.

Also, depending on the method of manufacturing the nonwoven fabric, it can be appropriately formed from a dense material to a material having many voids, a soft material to a hard material, and a thick material to a thin material.

The method for producing the nonwoven fabric may be any of a wet method and a dry method, and methods such as spun pond, melt blowing, flash spinning, and tow opening can be preferably used. Although nonwoven fabric strength than the fabric is weak, high productivity, labor, it has the advantage that even less of a burden of equipment cost, oxidized fiber of _c present invention for use in applications that do not require much strength Nonwoven fabrics are used for various types of flame resistance and fire prevention applications, and are particularly suitable for use as spatter sheets and flameproof insulation materials. Further, the carbon fiber nonwoven fabric of the present invention is suitably used as various electrode substrates, and is preferably used, for example, as an anode material of a sodium sulfur battery.

The specific resistance value of the carbon fiber fabric of the present invention is preferably 0.6 Ω · cm or less, more preferably 0.6 Ω · cm or less, and further preferably 0.4 Ω · cm or less. Such a relative If the resistance exceeds 0.6 Ω · cm, it cannot be used as an electrode material because the conductivity is too low. It is to be noted that the lower the specific resistance value is, the more preferable it is. The specific resistance value can be controlled by the degree of carbonization treatment described below, the number of carbon fibers per unit volume of the fabric, and the bulk density.

The method for producing a flame-resistant fiber material according to the present invention is characterized in that the acrylic fiber material comprises one or two of an organic compound other than an amine compound, a fluorine compound, a siloxane, a nitrate, and a nitrite (hereinafter abbreviated as a flame-stabilizing agent). It is characterized in that it is subjected to a flameproofing treatment at 180 to 300 ° C. in the presence of at least one kind of compound.

Here, the form of the acryl-based fiber material is not particularly limited, and may be an acryl-based fiber bundle in which single fibers are collected in a bundle or an acryl-based fiber fabric processed into a fabric.

When an acryl-based fiber bundle is used as the acryl-based fiber material, the fineness per 1 mm width of the acryl-based fiber bundle is preferably set to 1,0 from the viewpoint of high productivity when the acryl-based fiber bundle is subjected to the flame-resistant treatment. 0 0 to 80, OOO dtex / mm, more preferably 10, 00 0 to 75, 00 dte X Zmm, more preferably 15, 00 0 to 70, OOO dtex / mm It is good to perform a flame-proof treatment. If the fineness per 1 mm width of the acryl-based fiber bundle is lower than the above range, productivity may decrease, and if it is higher, runaway may occur during the oxidation treatment.

Here, the fineness per 1 mm width of the acrylic fiber bundle is a value obtained by dividing the fineness of the acrylic fiber bundle immediately before the introduction of the anti-oxidation treatment by the width of one yarn of the acrylic fiber bundle immediately before the introduction of the anti-oxidation treatment. It is. The width of one acrylic fiber bundle is averaged by stopping the driving of the running fiber bundle, measuring the width of one yarn with calipers at five points at 1 cm intervals in the longitudinal direction, and calculating the average. be able to.

The fineness per unit cross-sectional area of the acrylic fiber bundle is preferably from 500 to 7,500 dtex / mm ² , more preferably from 1,000 to 7, from the viewpoint of high productivity. It is preferable to carry out the flame-proof treatment at 300 dte X / mm ² , more preferably at 2,000 to 7,000 dtex / mm ² . The fineness per unit cross-sectional area of the acryl-based fiber bundle is lower. If it is lower than this range, the productivity may decrease. May be done. Here, the fineness per unit cross-sectional area of the acrylic fiber bundle is obtained by dividing the fineness of the acrylic fiber bundle immediately before the introduction of the oxidation treatment by the cross-sectional area of one yarn of the acrylic fiber bundle immediately before the introduction of the oxidation treatment. Value. The cross-sectional area of one yarn of the acrylic fiber bundle was measured at five points in the width direction of one yarn by stopping the driving of the running yarn and using a commonly known photoelectric transmittance measuring device. On average, the fiber bundle thickness was determined and multiplied by the width of one yarn determined by the method described above.

Further, when performing the flame-resistant treatment, the acrylic fiber bundle which is the precursor fiber bundle may be treated in a so-called non-twist state without substantially burning, or a plurality of precursor fiber bundles may be treated. The yarn may be twisted and twisted for treatment in a twisted state. Further, an untwisting step for unburning the twisted fiber may be included.

When using an acryl-based fiber cloth as the acryl-based fiber material, the acryl-based fiber cloth may be subjected to the flame-proofing treatment in one sheet, or may be subjected to the flame-proof treatment in a state where two or more sheets are overlapped. The total weight per unit area of the acryl-based fiber fabric to be treated is preferably 20 to 2,000 g / m ² , more preferably 50 to 1,500 g / m ² , and Preferably, it is 70 to 1,000 g Zm ² . If the total weight per unit area of the acryl-based fiber fabric is lower than the above range, the productivity may be reduced, and if the total weight is higher, runaway may occur during the oxidation treatment.

The ambient temperature of the oxidization treatment is preferably 180 to 300 ° C., more preferably 200 to 300 ° C., and further preferably 220 to 300 ° C. If the ambient temperature is lower than the above range, the penetration of the flame retardant into the fiber may be hindered and the efficiency of the flame retardant treatment may be reduced.If the ambient temperature is higher than the above range, runaway occurs during the flame retardant treatment. There is.

The oxidizing agent can be contained in the oxidizing atmosphere as evaporated vapor, or can be used as a liquid phase. Here, the “evaporated vapor” means a state in which the oxidizing agent is heated and vaporized into fine particles, and may be a so-called wet vapor state in which a part thereof is aggregated.

The "atmosphere containing vaporized vapor" refers to the saturated state of one or more of organic compounds, fluorine compounds, siloxanes, nitrates, and nitrites, excluding amine compounds, that is, 100%. Evaporation steam atmosphere may be used. For example, a slight amount of an oxidizing gas such as air or oxygen or an inert gas such as nitrogen, helium, or argon may be mixed.

In the present invention, the oxidizing treatment may be carried out either in the atmosphere containing vaporized vapor of the oxidizing agent or in the liquid phase, or in the liquid phase with the treatment in the atmosphere containing vaporized vapor. May be combined as appropriate.

In the present invention, the time required for the oxidation treatment can be determined according to the reaction rate of the oxidation treatment, preferably 0.01 to 240 minutes, more preferably 5 to 100 minutes, and furthermore Preferably, it can be appropriately set in the range of 10 to 50 minutes. The atmospheric pressure of the oxidization treatment is usually preferably set to the atmospheric pressure because it is difficult to seal, but by performing the treatment in a pressurized atmosphere, the time required for the oxidization treatment can be shortened.

Further, the oxidation treatment may be performed by any of so-called batch processing and continuous processing, but continuous processing is preferable from the viewpoint of productivity.

Further, at the time of the flame-resistant treatment, the draw ratio is preferably set to a draw ratio exceeding 1.0 from the viewpoint of improving the physical properties in the fiber direction, for example, the draw ratio is preferably 1.0 to 1.7, It is more preferably from 1.1 to 1.7, and still more preferably from 1.3 to 1.7. If it is lower than the range, the physical properties are deteriorated, and if it is higher, the yarn may be broken during the flame-proofing treatment. It is considered that the reason why the high drawing can be performed stably is that the flameproofing agent uniformly transfers heat to the entire fiber material, or that the flameproofing agent plasticizes the acryl-based fiber.

Specific examples of the organic compound other than the amine compound used in the present invention include aromatic compounds such as polysubstituted alkylbenzene, naphthalene, alkylnaphthalene, biphenyl, alkylbiphenyl and triphenyl hydride, formamide, acetoamide, and pioamide. Such as amides, ketones such as phenylmethyl ketone, phenylethyl ketone, phenylpropyl ketone, and diphenylketone; monoalcohols such as phenylmethyl alcohol, phenylethyl alcohol, and phenylpropyl alcohol; ethylene glycol; diethylene glycol , Triethylene glycol and other alkylene glycols, glycerin and other tridalicols, and Pentra Elytrit and other tetraglycols and higher polyglycols, polyol compounds, and ethylene glycol. Rico Monoalkyl ethers such as monomethyl, monoethyl, monopropyl, monobutyl and the like, and monoaryl ethers such as ethylene glycol monophenyl and monotolyl, diphenyl ethers, alkylphenyl ethers and alkylaryl esters and the like. .

In addition, aliphatic carboxylic acid esters such as dimethyl succinate, getyl and dipropyl, ester compounds such as methyl, ethyl, propyl and butyl benzoate, and aromatic sulfonic acid such as dimethyl terephthalate, getyl and dipropyl Diesters and ester glycols can also be used.

Further, thiol compounds, sulfonic acid compounds such as benzenesulfonic acid and P-toluenesulfonic acid, sulfone compounds such as dimethyl sulfoxide, getyl sulfoxide, and methylethyl sulfoxide, sulfin compounds, amine oxide compounds, and triphenylmethyl cation Nitro compounds such as nitro compounds, nitroxide compounds, dichlorodicyanobenzoquinone, naphthoquinone, anthraquinone, quinone, nitrobenzene, o-nitrotoluene, m-nitrotoluene, p-nitrotoluene, nitroxylene, and nitronaphthalene are also used. it can.

Further, paraffinic compounds, cycloparaffins and naphthenic compounds which are alkyl-substituted products thereof can also be used.

These also include compounds and mixtures known as various organic heating media, such as heating media containing aromatic hydrocarbons, alkylaromatic heating media, paraffinic heating media, and naphthenic heating media. Among them, alkylbenzene, alkylnaphthalene, biphenyl, diphenyl ether and the like are known to be used as a heat medium.

As the fluorine compound used in the present invention, a perfluoropolyether compound, an organic fluorine compound, a chlorine-substituted fluorine compound, a polyvinylidene fluoride compound, or the like can also be used.

The perfluoropolyether compound is not particularly limited, but a compound known to be used as a heat medium lubricant can be used as appropriate.

The organic fluorine compound and the chlorine-substituted fluorine compound are not particularly limited, but those known to be used as a solvent can be appropriately used.

The polyvinylidene fluoride compound is not particularly limited, but may be used as a lubricant. Any of known applications can be used as appropriate.

Various siloxanes can be used as the siloxane used in the present invention, and among them, organic boryl siloxanes known as silicones such as phenylsilicone compounds are preferable. These include those known as silicone-based lubricants and silicone-based heat transfer media.

In the present invention, various nitrates and nitrites such as potassium nitrate, sodium nitrite, sodium nitrate and mixtures thereof can also be used as the flame retardant. These include those known as inorganic heating media.

In the present invention, two or more kinds of the above-mentioned oxidizing agents may be used in combination. Above all, from the viewpoint of the heat resistance of the evaporated vapor, it is preferable to use an aromatic compound, and it is more preferable to use an aromatic hydrocarbon and / or an aromatic ether.

In addition, it is preferable that part or all of the oxidizing compound is a so-called oxidizing compound, because the efficiency of the oxidizing treatment increases. Here, the oxidizing compound means an organic compound having a hydrogen accepting property or an oxygen releasing property. For example, a sulfone compound, a sulfin compound, a quinone, a nitro compound and the like can be mentioned. More specifically, dimethyl sulfoxide, tetrachloro-1,2,2, described in Chapter 6, page 299 of “Experimental Chemistry Course 23, Organic Synthesis 4, Oxidation Reaction” (publisher: Maruzen) — Benzoquinone, benzene and the like.

If the dissolution of fibers, yarn, or breakage occurs due to too strong an affinity between these compounds and acrylic fibers, a part of the polymer skeleton of acryl-based fibers may have a three-dimensional structure such as ethylene dimethacrylate. A part or all of the polymer component can be cross-linked by introducing a cross-linking component, or by using an oxidation treatment, an ultraviolet treatment, an electron beam treatment or the like. In the present invention, organic compounds and reaction products adhering to the fibers after the oxidization treatment can be removed by drying. Further, it can be washed and removed by using an organic solvent such as methyl alcohol, ethyl alcohol, acetone, dimethyl sulfoxide, N, N-dimethylformamide, polyethylene dalicol, or a combination of such an organic solvent and water. Alternatively, it can be washed away with an optional surfactant and water. Potassium nitrate, sodium nitrite, sodium nitrate not soluble in organic solvents Compounds such as the compounds can be washed away using a solvent that dissolves them.

The cleaning efficiency is improved by using physical methods such as a roller, a guide, a nip roller, and an ultrasonic wave at the time of the cleaning.

In the present invention, the oxidation treatment may be performed in an environment in which substantially no oxygen is present, that is, in an environment in which the amount of oxygen is reduced to such an extent that an oxidation reaction by oxygen does not occur.

Alternatively, in order to improve the heat resistance of the obtained oxidized fiber, or to enhance the physical properties of the carbon fiber, the fiber material before or after the oxidization treatment is preferably placed in an oxidizing atmosphere. The oxidation treatment can be carried out at 0 to 400 ° C., more preferably at 100 to 350 ° C., and even more preferably at 180 to 300 ° C.

The oxidation treatment here means, for example, a heated air treatment, and the required time for the oxidation treatment is preferably between 0.01 to 60 minutes, and between 0.01 and 30 minutes. The time is more preferably between 0.01 and 10 minutes. If the ratio is out of the range, the processability may decrease, and the yield and the quality of the obtained flame-resistant fiber material may decrease. '

In this case, the steps of the oxidation treatment and the oxidation treatment may be discontinuous or continuous, but continuous treatment is preferred from the viewpoint of productivity.

In addition, the oxidation treatment can be performed at 180 to 300 ° C. by blowing or finely dispersing an oxidizing gas at the same time as the oxidation treatment. In this case, flame resistance and oxidation can be performed simultaneously, which is preferable in that the process can be shortened. Oxygen, nitrogen oxide, or the like can be used as the oxidizing gas here.

When an acryl-based fiber bundle is used as the acryl-based fiber material, the fineness per 1 mm of the width of the fiber bundle at the time of the oxidation treatment is preferably 1.0000 to 80, OOO dtex Zmm, more preferably 10%. , 000-750, 000 dtex xmm, more preferably, 15, 000-75, 000 dtex / mm. If it is too high, runaway may occur during the oxidation treatment.

The weight of the treated fiber per unit cross-sectional area of the fiber bundle during the oxidation treatment is preferably 500 to 7,500 dtex / mm ² , more preferably 1,000, from the viewpoint of high productivity. ~ 7,500 dte xZmm ² , more preferably, 2,000 ~ 7,500 dt may in the range of e xZmm ^2, reduced low and productivity than the range, it may result in high runaway during the oxidation process.

Acrylic fiber fabrics can be treated with one sheet, but two or more sheets may be overlapped, and the total weight per unit area is preferably 20 to 2,000 g / m ² . Should be 50 to 1,500 g / m ² , more preferably 70 to 1,1 and OOO gZm ^{2. If} it is lower than the range, the productivity will decrease. It can happen.

In the carbon fiber material of the present invention, the oxidized fiber material is prepared in an inert atmosphere, preferably at least 300 ° C., less than 2,000 ° C., and more preferably 800 to 2,000 ° C. C, more preferably 1,000 to 1,800 ° C., particularly preferably 1,200 to 1,800.

By using the oxidized fiber material of the present invention, the yield during the carbonization treatment (hereinafter abbreviated as the carbonization yield) can be set to 50% or more. The higher the carbonization yield, the higher the productivity and the lower the cost of the carbon fiber material. Further, the flame-resistant fiber material of the present invention can increase the carbonization yield when subjected to carbonization treatment to 50 to 65%, and more preferably to 55 to 65%. Further, in an inert atmosphere, and when the carbonization treatment at 135 ° C., the carbonization yield is preferably 50 to 65%, more preferably 52 to 65%, It is particularly preferred that it is between 54 and 65%. In the carbon fiber material of the present invention, the outermost surface measurement value A 1 of π * / σ * obtained by measuring the cross section of a single fiber by electron energy loss spectroscopy using a field emission The ratio A 1 ZA 2 to the value A 2 is usually 0.883 to 0.94, preferably 0.85 to 0.93, and more preferably 0.87 to 0.92. .

Here, 7T * / σ * represents the degree of crystallinity, and the larger the value, the higher the degree of crystallinity. In other words, the carbon fiber material of the present invention indicates that the crystallinity on the surface of the single fiber is smaller than the crystallinity inside the single fiber. By having such a structure, since the crystallinity of the outermost surface of the single fiber is low, the difference in elastic modulus from the resin is reduced, and the adhesive strength with the resin is improved.

In the carbon fiber material of the present invention, the degree of crystal orientation 7t 002 measured by wide-angle X-ray diffraction is preferably from 75 to 99%, more preferably from 80 to 97%. This degree of crystal orientation is determined by a wide-angle X-ray diffraction method. X-rays use Cu Κ α, and Cu K j3 is removed by a nickel filter. It can be calculated from the half-width H of the intensity distribution obtained by scanning the crystal peak corresponding to the plane index (002) near 2Θ = 26 ° in the circumferential direction by the following equation.

Crystal orientation degree π 0 0 2 = (1 8 0 — H) Z 18 0

If the degree of crystal orientation is less than 75%, the physical properties may be reduced. Further, the carbon fiber material may be further heated to 2,000 to 3,000 in an inert atmosphere to obtain a graphite fiber material having more excellent strength characteristics.

The obtained carbon fiber material and graphite fiber material can be electrolytically treated for surface modification. For the electrolytic solution used for the electrolytic treatment, use an acidic solution such as sulfuric acid, nitric acid, or hydrochloric acid, or an aqueous solution such as sodium hydroxide, potassium hydroxide, tetraethylammonium hydroxide, or a salt thereof. Can be. Here, the amount of electricity required for the electrolytic treatment can be appropriately selected depending on the carbon fiber material and the graphite fiber material to be applied.

By such electrolytic treatment, in the obtained composite material, the adhesion between the carbon fiber material and the graphite fiber material and the matrix can be optimized, and the brittle fracture of the composite material due to too strong adhesion, and the tensile strength in the fiber direction can be achieved. And the problem of poor tensile strength in the fiber direction, but poor adhesion to the resin and no strength characteristics in the non-fiber direction is solved. The strength characteristics balanced in both directions are developed.

Thereafter, a sizing treatment can be performed to impart convergence to the obtained carbon fiber material. As the sizing agent, a sizing agent having good compatibility with the resin can be appropriately selected according to the type of the resin used.

Example Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples and the like.

In the examples, each physical property value was measured by the following method.

The average oxygen concentration in the fiber of the oxidized fiber material was obtained as the ratio OZC between the carbon amount C measured by elemental analysis and the oxygen amount 0 measured by oxygen analysis.

The sample, the flame-resistant fiber material, was dried in a vacuum at 40 for 5 hours before measurement. For elemental analysis, a fully automatic elemental analyzer Vario EL manufactured by Yanagimoto Kagaku Kogyo Co., Ltd. was used.Carbon, hydrogen, and nitrogen were used at a sample decomposition furnace temperature of 950 ° C and a reduction furnace temperature of 500 ° C. Was measured.

For oxygen analysis, HE RAEUS C HN-ORAPID fully automatic analyzer manufactured by Sebel Hegner, using a non-dispersive spectrometer (Bin 0 s) as the detector, sample decomposition furnace temperature 1 140, fractionated fractionation Oxygen was measured at a tube temperature of 1 140 ° C.

The residual ratio of nitrile groups in the oxidized fiber material is determined by measuring the ratio of the absorption band intensity of the nitrile group of the oxidized fiber material to the absorption band intensity of the nitrile group of the acrylic copolymer (precursor fiber material). It was determined by measuring by spectroscopy. An example of the measurement procedure is shown below.

1. Preparation of tablets for infrared spectroscopy

The acrylic copolymer to be measured and the oxidized fiber material obtained by the heat treatment (oxidation treatment) were frozen with liquid nitrogen and pulverized to obtain powder sample A and powder sample A, respectively. Powder sample B was prepared by mixing KB rlg and 1 Omg of potassium ferrocyanide.

The powder sample was mixed in the following mixing ratio while being ground in a mortar to obtain a mixed powder, and tablets for infrared spectroscopy were prepared using a press.

Sample before heat treatment: powder sample A 2 mg, powder sample B 1 Omg, KBr 300 mg Sample after heat treatment: powder sample A '2 mg, powder sample B 1 Omg, KB r 30 Omg

2. Measurement of residual rate of nitrile group

Regarding the tablet for infrared spectroscopy, the ferrocyanation force The absorbance ratio D2250 / D2500 of the band and the nitrile group at 2250 cm-1 band was measured.

The average value of the absorbance ratios (n = 3) was taken, and the residual ratio of nitrile groups was determined by the following equation. Residual rate of nitrile group = Absorbance ratio of sample after heat treatment Z Absorbance ratio of sample before heat treatment X 100%

In this example, a Paragon 100 model manufactured by PerkinElmer, Inc. was used as the infrared spectrometer.

The average oxygen concentration 〇1 on the surface of the oxidized fiber was determined by X-ray photoelectron spectroscopy. An example of the procedure is shown below. First, the flame-resistant fiber material to be measured was cut into an appropriate length, spread on a stainless steel sample support, and then measured under the following conditions.

• Photoelectron escape angle: 35 degrees

-Source: 1 << 1, 2 (1486.6 eV)

• Degree of vacuum in the sample chamber: l X 10 -8 T Or r

Next, in order to correct the peak due to charging during measurement, the binding energy value BE of the main peak of C 1 s was adjusted to 284.6 eV.

Next, the C ls peak area [C ls] is obtained by drawing a straight-line base line in the range of 282 to 2996 eV, and the 〇 ls peak area [O ls] is 5 28 to It was determined by drawing a linear baseline in the range of 540 eV.

The oxygen concentration O 1 on the fiber surface was determined by the following equation from the ratio of the above 〇1 s peak area [O ls], C 1 s peak area [C ls], and the sensitivity correction value unique to the apparatus.

01 = ([O l s] / [C l s]) / (sensitivity correction value k)

In this example, a model SSX-100-206 manufactured by US SSI was used as a measuring device. The sensitivity correction value k of the 〇 1 s peak area with respect to the C 1 s peak area unique to this device was 2.73.

After the oxidized fiber material to be measured was frozen with liquid nitrogen and crushed, the average oxygen concentration O 2 was determined by the above-described measurement method.

02 = ([Ols] / [Cls]) / (sensitivity correction value k) <Crystallinity of carbon fiber material>

As an index of the crystallinity of the carbon fiber material, π * / σ * was measured by electron energy loss spectroscopy using a field emission electron microscope. π * was determined from the peak intensity at 285 eV, and * was determined from the peak intensity at 293 to 295 eV.

In this example, HF-2210 manufactured by HI TACH I was used as a field emission electron microscope. Measurement conditions were an acceleration voltage 2 0 0 kV, the sample absorption current .1 0 _ ⁹ A, measurement time 6 0 seconds, and the beam diameter l nm ^, several points to centered from the outermost surface of the single fiber cross-section of the carbon fiber material It was measured.

The degree of crystal orientation 7t002 of the carbon fiber material was determined by a wide-angle X-ray diffraction method. Using the X-ray source Cu K a line from which the Cu K / 3 line has been removed by the Ni filter, the crystal peak corresponding to the plane index (002) near 20 = 26 ° From the intensity distribution half width H obtained by scanning in the direction, the degree of crystal orientation π 002 was calculated by the following equation.

Crystal orientation Τ 0 0 2 = (1 8 0— Η) Ζ 1 8 0

In this example, a measuring / analyzing apparatus was used: a 4036 A2 type X-ray diffractometer, a goniometer-evening, a counting recorder RAD-C type (both manufactured by Rigaku Denki Co., Ltd.). Other conditions were as follows.

Tube voltage: 40 kV

Tube current: 20 mA

Tensile force was applied to the single-fiber-embedded resin test piece in the fiber axis direction to generate a strain of 10%, and then the number of fiber breaks n in a range of 20 mm in the center of the test piece was measured by an optical microscope. Thus, the average broken fiber length 1 was determined as 1 = 2 O Zn.

The bond strength at the fiber-resin interface was determined by: σ · d / 21c. Here, 1 c is the critical fiber length, which is determined from the average broken fiber length 1 to 1 c = 41 Z 3. Σ is the single fiber strength at the critical fiber length, and d is the fiber diameter.

Here, as a resin for embedding a single fiber, bisphenol A-type epoxy resin compound Epicoat (registered trademark) 828 (manufactured by Japan Epoxy Resin Co., Ltd.) / N-aminoethyl pipera Gin = 15 parts: 15 parts: A mixture of 4.9 parts was used. Next, a carbon fiber single fiber is impregnated in the longitudinal direction of a Teflon (registered trademark) frame having a thickness of 2 mm, a width of 10 mm, and a length of 150 mm into the frame, and the mixture is impregnated at room temperature. After pre-curing for about 12 hours, it was heated at 100 ° C. for 120 minutes and post-cured to prepare a single fiber embedded resin test piece.

Prepare a rectangular paper card with a 5 mm wide slit hole, pass a single fiber to the slit hole, temporarily fix both ends, and apply a single piece of the same card with the instant adhesive applied. Secure the fiber so that it does not rise from the card. The card to which the single fiber was fixed was attached to a tensile tester, the both sides of the slit hole of the card were cut so as not to cut the single fiber, the entire card was immersed in water, and a tensile test was performed at a strain rate of 1%. (Number of measurement samples: 50 or more).

'' The tensile strength and tensile modulus of the carbon fiber bundle and graphite fiber bundle were measured according to JIS R7601. The tensile test piece was prepared by impregnating a carbon fiber bundle with the following resin composition and curing by heating under the conditions of 130 ^ and 35 minutes.

Resin composition: 3,4-epoxycyclohexyl methyl 3,4-epoxycyclohexyl monohexyl propyloxylate (100 parts by weight) Z3 Boron fluoride monoethylamine (3 parts by weight) / acetone (4 parts by weight)

Measurement of specific resistance>

The carbon fiber fabric is sandwiched between two copper plates, and the electrical resistance is measured while compressing the fabric. The electrical resistance value decreases by compressing the fabric, but becomes constant when the thickness becomes smaller than a certain thickness. Using the electrical resistance value when it became constant and the sample thickness at that time measured with a micrometer, the specific resistance value was calculated by the following formula.

Specific resistance (Ω · cm) = Electric resistance (Ω) X Sample cross-sectional area (cm ² ) Z Sample thickness (cm)

[Example 1]

A copolymer consisting of 99.5 mol% of acrylonitrile and 0.5 mol% of itaconic acid is polymerized by a solution polymerization method using dimethylsulfoxide as a solvent. Ammonia gas was blown into the acryl-based copolymer while neutralizing the itaconic acid while injecting a gas until the pH reached 8.5, and a spinning stock solution having a copolymer component content of 22% was obtained. .

This spinning stock solution was discharged into the air once at 40 ° C using a spinneret with a diameter of 0.15 mm and a number of holes of 700,000, and after passing through a space of about 4 mm, The coagulated yarn was formed by a dry-wet spinning method in which the mixture was introduced into a coagulation bath consisting of an aqueous solution of 35% dimethyl sulfoxide controlled in step 3.

The coagulated yarn was washed with water by a conventional method, stretched 3.5 times in warm water, and further applied with an amino-modified silicone-based silicone oil agent to obtain a drawn yarn.

The drawn yarn is dried and densified using a heating roller at 180, and drawn in a pressure steam of 29.4 MPa, so that the total drawing ratio of the yarn is 13 times, An acryl-based fiber bundle with a single fiber fineness of 0.9 dtex and a filament count of 700,000 was obtained.

The fineness of width 1 per mm of such Akuriru fiber bundle 3 0, 0 0 0 dtex / mm, 4 a fineness per unit sectional area of the acrylic fiber bundle, 0 0 0 a dtex / mm ^2, substantially Without imparting twist, the film was subjected to a flame resistance treatment at 244 for 30 minutes in an evaporative vapor atmosphere of diethylene glycol while being stretched 1.5 times. The temperature inside the fiber bundle only rose to 260 ° C, and a stabilized flame-resistant fiber bundle was obtained.

The oxidized fiber bundle, a width of 1 fineness per mm 3 0, OOO dtex Zmm, the fineness per unit sectional area of the fiber bundles 4, 0 0 0 dtex / mm 2 of fiber bundles, in air, 3 Oxidation treatment at 00 ° C for 5 minutes, then pre-carbonizing at 300 to 800 ° C while stretching 1.04 times in an inert atmosphere, then 1, 40 in an inert atmosphere Carbonized at 0 ° C.

Thereafter, anodizing treatment of 10 coulomb / g (g: weight of carbon fiber) was performed in an aqueous sulfuric acid solution. As a result, a carbon fiber bundle having good characteristics was obtained.

The obtained carbon fiber bundle was further graphitized at 2,000 in an inert atmosphere, and then anodized at 10 Coulomb Zg in an aqueous sulfuric acid solution. As a result, a graphite fiber bundle having good strength characteristics was obtained. .

[Example 2] Both the fineness per 1 mm width of the acrylic fiber bundle when oxidizing and the fineness per lmm width of the fiber bundle when oxidizing in air are set to 75, OOO dtex / mm. except for changing the Akuriru system together 7 fineness per unit cross-sectional area at the time of fineness and oxidation per unit sectional area of the fiber bundle, 3 0 0 dte xZmm ² when in the same manner as in example 1, flame resistant Fiber bundles, carbon fiber bundles and graphite fiber bundles were obtained. The temperature inside the fiber bundle during the oxidation treatment rose only to 275 ° C, and the oxidation-resistant fiber bundle was obtained stably. The obtained oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Example 3]

Both the fineness per 1 mm width of the acryl-based fiber bundle during the oxidation treatment and the fineness per 1 mm width of the fiber bundle during the oxidation treatment in air are set to 10 and OOO dte xZ mm, respectively. and except for changing both 1, 5 0 0 dtex / mm 2 \ Z fineness per unit cross-sectional area at the time of fineness and oxidation per unit cross-sectional area of Akuriru fiber bundle at the time of the in the same manner as in example 1 Thus, an oxidized fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained. The temperature inside the fiber bundle at the time of the flame treatment increased only to 250, and the flame-resistant fiber bundle was stably obtained. The obtained oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Example 4]

When the acrylic fiber bundle obtained in the same manner as in Example 1 was subjected to a flame-resistant treatment, the fineness per 1 mm width of the acrylic fiber bundle was set to 90,000 dtex / mm, and the fineness per unit sectional area of the acrylic fiber bundle 8, and OOO dte xZ mm ^2, without imparting twist to substantially while stretched 5 times 1., in the liquid phase atmosphere of diethylene Dali call, 2 The sample was subjected to oxidization at 20 ° C. Although it took 50 minutes for the specific gravity to become equivalent to that of Example 1, the same treatment as in Example 1 was continued, and the oxidized fiber bundle, carbon fiber bundle, and graphite showing good characteristics were obtained. A fiber bundle was obtained.

[Example 5]

An oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber bundle were obtained in the same manner as in Example 1, except that the draw ratio for the oxidization treatment was changed to 1.15 times. The temperature inside the fiber bundle during the oxidation treatment increased only to 26.5, and the oxidation-resistant fiber bundle was obtained stably. Obtained flame resistance The carbonized fiber bundle, the carbon fiber bundle and the graphite fiber bundle showed good properties.

[Example 6]

An oxidized fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained in the same manner as in Example 1 except that the draw ratio in the oxidization treatment was changed to 0.95. The temperature inside the fiber bundle during the oxidation treatment increased only to 263, and the oxidation-resistant fiber bundle was obtained stably. Although the physical properties of the obtained oxidized fiber bundle, carbon fiber bundle and blackened fiber bundle were slightly reduced, other characteristics were good.

[Example 7]

A flame-resistant fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained in the same manner as in Example 1 except that the flame-resistant treatment agent was a one-to-one mixed solution of diethylene dalicol and nitrobenzene. The temperature inside the fiber bundle during the flame-resistant treatment rose only to 263 ° C, and the flame-resistant fiber bundle was stably obtained. The obtained oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle exhibited good characteristics.

[Example 8]

An oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber bundle were obtained in the same manner as in Example 2 except that the oxidizing agent was a 1: 1 mixture of diethylene glycol and ditrobenzene. The temperature in the bundle rose only to 277, and a flame-resistant fiber bundle was obtained stably. The obtained oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Example 9]

An oxidized fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained in the same manner as in Example 1 except that the oxidizing agent was perfluoropolyether. The temperature inside the fiber bundle during the oxidation treatment increased only to 273 ° C, and the oxidation-resistant fiber bundle was obtained stably. The resulting oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Comparative Example 1]

The flame resistance treatment was carried out in the same manner as in Example 6, except that the atmosphere for the flame resistance treatment was changed to air and the temperature was changed to 20 O :. It took 300 minutes for the specific gravity to become equivalent to that of Example 6. Subsequent carbonization and graphitization treatments yielded carbon fiber bundles and graphite fiber bundles, but the physical properties were low. [Comparative Example 2]

The flame resistance treatment was carried out in the same manner as in Example 2 except that the atmosphere during the flame resistance treatment was changed to air and the temperature was changed to 21.0 ° C. It took 240 minutes for the specific gravity to become equivalent to that of Example 2. Subsequent carbonization and graphitization treatments yielded carbon fiber bundles and graphite fiber bundles, but the physical properties were low.

table 1

Filament oxidation treatment

number

(Present / bundle) during treatment atmosphere processing width 1mm processing area Imm ² draw ratio processing,蠑度維束in temperature per搽度woven cc) per (dtex / mm) (dtex / mm!) (¾) Example 1 700000 Ι レン Ι レンク Rico-* 244 30000 4000 1.5 260

(Steam)

Example 2 Same as above Same as above 75000 7300 Same as above 275 Example 3 Same as above Same as above Same as above 10000 1500 Same as above 250 Example 4 Same as above -yi Tyrenko's 2-reel 220 90000 8000 Same as above 270

(Liquid phase)

Example 5 Same as above. ** Ichirenk's recall 244 30000 4000 1.15 265

(Steam)

Example 6 Same as above Same as above Same as above Same as above 0.9 263 Example 7 Same as above Same as above

/ Nitroheinsen

= 1/1 (steam)

Example 8 Same as above.

/ Nito π

= 1/1 (steam)

Example 9 Same as above Λ · -7ΡΠ * 'Riete Same as above Same as above Same as above 273

* (Liquid phase)

Comparative Example 1 Same as above Air 200 Same as above 0.9 280 Comparative Example 2 Same as above 210 5000 1000 Same as above 278 Table 2

* 1 O 1: Fiber surface average oxygen concentration

* 2 O 2: average oxygen concentration of frozen and ground fiber

Table 3

* 1 A1: Surface measurement value of π * / σ *

* 2 A2: Simple extension of 7C * / σ * 锥 internal maximum

[Example 10] '

A copolymer consisting of 99.5 mol% of acrylonitrile and 0.5 mol% of itaconic acid was polymerized by a solution polymerization method using dimethylsulfoxide as a solvent, and ammonia gas was further blown until ρΗ became 8.5. While neutralizing, an ammonium group was introduced into the acryl-based copolymer to obtain a spinning stock solution having a copolymer component content of 22%.

Using a spinneret with a diameter of 15 mm, a number of holes of 6, and a number of holes of 00, this spinning stock solution was temporarily discharged into the air, passed through a space of about 4 mm, and then controlled at 3 ° C. A coagulated yarn was formed by a dry-wet spinning method in which the coagulated yarn was introduced into a coagulation bath composed of an aqueous solution of 35% dimethyl sulfoxide.

The coagulated yarn was washed with water by a conventional method, stretched 3.5 times in warm water, and further applied with an amino-modified silicone silicone oil agent to obtain a drawn yarn. The drawn yarn is dried and densified using a heating roller at 180 ° C, and drawn in a pressurized steam of 29.4 MPa, so that the total drawing ratio of the yarn is 13 times. An acrylic fiber bundle having a single fiber fineness of 0.9 dte X, a single fiber count of 24, and a single fiber count of 0.0 was obtained.

The fineness of width 1 per mm of such Akuriru fiber bundle 2 0, 0 0 0 dtex / mm, a fineness per unit sectional area of the acrylic fiber bundle 3, and OOO dte xZmm ^2, applying twists to substantially Without elongation, it was subjected to a flame-resistance treatment at 244 for 30 minutes in an evaporative steam atmosphere of diethylene glycol while being stretched 1.5 times, to obtain a flame-resistant fiber bundle having good properties.

In the same manner as in the flame-proof treatment, the fineness of the acrylic fiber bundle per 1 mm width was set to 20.000 dtex / mm, and the fineness per unit cross-sectional area of the acrylic fiber bundle was determined. 3, 00 0 dte xZmm ² and then, without imparting twist to the substantially air, 3 treated 0 0 ° C for 5 min, then in an inert atmosphere, 1.3 while stretched 04 times 0 Precarbonization was performed at 0 to 800 ° C, and then carbonization was performed at 1,400 ^ in an inert atmosphere. Thereafter, anodizing treatment of 10 coulombs Zg was performed in an aqueous sulfuric acid solution. As a result, a carbon fiber bundle having good characteristics was obtained.

The obtained carbon fiber bundle was further graphitized at 2,000 ^ in an inert atmosphere, and then anodized at 10 coulomb / g in an aqueous sulfuric acid solution. As a result, a graphite fiber bundle having good characteristics was obtained. ,

[Example 11]

An oxidized fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained in the same manner as in Example 9, except that the oxidization treatment with diethylene dalicol was changed to the liquid phase. The obtained flame-resistant fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Example 12]

An oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber bundle were obtained in the same manner as in Example 9, except that the draw ratio during the oxidization treatment with diethylene glycol was changed to 1.15. The resulting oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Example 13]

Oxidation treatment was performed with a 1: 1 mixture of diethylene glycol and ditrobenzene. Except for the above, an oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber bundle were obtained in the same manner as in Example 9. The obtained oxidized fiber bundle, carbon fiber bundle and graphite fiber bundle showed good characteristics.

[Examples 14 and 15]

An oxidized fiber bundle, a carbon fiber bundle and a graphite fiber bundle were obtained in the same manner as in Example 12 except that the number of filaments of the fiber bundle to be treated was variously changed as shown in Table 1. The resulting oxidized fiber bundle, carbon fiber bundle, and graphite fiber exhibited good properties.

[Example 16]

An oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber were obtained in the same manner as in Example 9 except that the oxidization treatment was performed in the liquid phase of perfluoropolyether. The resulting oxidized fiber bundle, carbon fiber bundle, and graphite fiber bundle exhibited good characteristics.

[Example 17]

An oxidized fiber bundle, a carbon fiber bundle, and a graphite fiber bundle were obtained in the same manner as in Example 9 except that the stretching in the oxidization treatment was changed to 0.9 times. The single fiber tensile strength of the obtained oxidized fiber bundle was slightly lower than that of Example 9. The degree of crystal orientation π 002 of the obtained carbon fiber was slightly low, and the elastic modulus was slightly low.

[Comparative Example 3]

The acrylic fiber bundle obtained in Example 9 was set to have a fineness per unit width of 1 mm of the acrylic fiber bundle of 200,000 dtex / mm and a fineness per unit cross-sectional area of the acrylic fiber bundle of 3,0. 0 0 dtex ZMM ² and then, without imparting twist to substantially zero. while stretched nine times in air at atmospheric pressure 1 0 1 3 h P a, is treated oxidization with 2 6 0 ° C Thus, an oxidized fiber bundle was obtained. The residual rate of nitrile groups in the obtained flame-resistant fiber was low, and O 1 / O 2 was low.

After the oxidation treatment, the carbonization was carried out at 300 to 800 ^ in an inert atmosphere while being stretched 1.04 times, and the carbonization treatment was carried out at a temperature of 1,400X. After the carbonization, anodization was performed at 10 coulomb / g in a sulfuric acid aqueous solution to obtain a carbon fiber bundle. The carbonization yield at this time was somewhat low. A1ZA2 of the obtained carbon fiber was high, and the bonding strength was low.

The obtained carbon fiber bundle is further graphitized at 2,000 in an inert atmosphere. After that, anodizing treatment of 10 coulomb / g was performed in a sulfuric acid aqueous solution to obtain a graphite fiber bundle.

[Comparative Example 4]

Except that the number of filaments was changed, the flame resistance treatment was performed in the same manner as in Comparative Example 3, but the yarn was broken due to internal heat storage during the flame resistance treatment. Table 4

Filtration Flameproofing treatment

number

(Books / bunch) Processing atmosphere Processing width 1mm Processing area IranT Stretching ratio During processing, weaving degree per squash area Area of wrapper temperature inside bundle (dt ex / ram) (dt ex / mm ² ) CC) Example 24000 'I-Chilenk リ Rico-A 244 20000 3000 1.5 265

10 (steam)

Example Same as above.

11 (liquid phase)

Example Same as above. I 'Ichirenk' Rikoru Same as above Same as above 1.15 263

12 (steam)

Example Same as above Shishi 'Ichirenk' Recall Same as above Same as above 1.5 265

13 / Nitrohe

= 1/1 (steam)

Example 48000 Same as above Same as above Same as above Same as above 267

14

Example 96000 Same as above Same as above Same as above Same as above 272

Fifteen

Example Same as above 'Λ · -Fluoro! Rie-Tel 260 Same as above Same as above 274

16 (liquid phase)

Example 24000 Shishi 'I Chirenku' Recall 244 Same as above 0.9 255

17/2 π π

= 1/1 (steam

Comparative Example 24000 Air 260 Same as above 0.9 275

Three

Example of relatives 48000 Same as above 260 Same as above Same as above 0.9 279

Four Table 5

* 1 O 1: average oxygen concentration on the surface of the nipple

* 2 02: Frozen ground fiber average oxygen concentration

Table 6

* 1 A 1: re * Ζσ * outermost surface measured value

* 2 A 2: 7C * Ζσ * single fiber internal maximum value

[Example 18]

The acryl fiber obtained in the same manner as in Example 1 was used to fabricate a woven fabric having a weight per unit area of 200 gZm ² using an air jet loom. Four acrylic fiber woven fabrics each having a total weight per unit area of 800 g / m ² were subjected to a flameproofing treatment at 244 for 30 minutes in a diethylene glycol evaporation steam atmosphere. The mixture was treated at 300 ° C. for 5 minutes in the air to obtain an oxidized fiber woven fabric. This oxidized fiber woven fabric is pre-carbonized at 300 to 800 ° C in an inert atmosphere, then carbonized at 1,400 ° C in an inert atmosphere, and carbonized at a carbonization yield of 54%. A fiber fabric was obtained. Thereafter, an anodic oxidation treatment of 10 coulomb / g was performed in an aqueous sulfuric acid solution. As a result, a carbon fiber woven fabric having good characteristics was obtained.

[Example 19]

A flat knitted fabric having a weight per unit area of 200 gZm ² was prepared from the acrylic fiber obtained in Example 1 using a weft knitting machine. 4 layers of this acryl fiber knitted fabric When the total weight per unit area was set to 800 g Zm ² and subjected to a flame-proof treatment under the same conditions as in Example 17, a flame-resistant fiber knit was obtained. This flame-resistant fiber knitted product was carbonized under the same conditions as in Example 17 to obtain a carbon fiber knitted product with a carbonization yield of 54%.

[Example 20]

The acryl-based fiber obtained in Example 1 was subjected to crimping treatment to obtain a staple fiber having a cut length of 50 mm. Using the staple fiber, a web was produced by a known method, and the web was laminated and punched with a $ 21 dollar to produce an acrylic fiber nonwoven fabric of ²⁰⁰ g Zm ² . At this time, the yield of the obtained nonwoven fabric was 98% with respect to the input amount of the acrylic fiber. Four acryl-based fiber non-woven fabrics each having a total weight per unit area of 800 g Zm ² were subjected to a flame-proof treatment under the same conditions as in Example 17; Obtained. This flame-resistant fiber nonwoven fabric was carbonized under the same conditions as in Example 17 to obtain a carbon fiber nonwoven fabric with a carbonization yield of 55%.

[Comparative Example 5]

When those total weight per unit area overlapping four to Akuriru fiber fabric obtained in Example 1 7 is a 8 0 0 g Zm ^2, in an air atmosphere and heated in 2 2 0 ° C, Although flame resistance could be achieved without firing, it took about 200 minutes for the density to exceed 1.35 cm ³ . The obtained oxidized fiber woven fabric was carbonized under the same conditions as in Example 17 to obtain a carbon fiber woven fabric with a carbonization yield of 47%.

[Comparative Example 6]

The acrylic fiber obtained in Example 1 was heated at 240 ° C. in an air atmosphere, and after 120 minutes, an oxidized fiber having a density of 1.35 g Z cm ^s was obtained. Using this oxidized fiber, a nonwoven fabric was prepared under the same conditions as in Example 19, and the powder of the oxidized fiber was remarkable. The yield of nonwoven fabric was as low as 70%. The obtained flame-resistant fiber nonwoven fabric was carbonized under the same conditions as in Example 17 to obtain a carbon fiber nonwoven fabric with a carbonization yield of 50%.

Table 1 shows the oxidizing treatment methods of Examples 1 to 9 and Comparative Examples 1 and 2, and Tables 2 and 3 collectively show the properties of the obtained oxidizing fiber, carbon fiber and graphite fiber. As shown in Tables 1-3, The oxidized fiber, carbon fiber and graphite fiber of the present invention showed good properties.

Table 4 shows the flameproofing treatment methods of Examples 10 to 17 and Comparative Examples 3 and 4, and Tables 5 and 6 summarize the properties of the obtained flameproofed fibers, carbon fibers, and graphite fibers.

Table 7 shows the properties of the oxidized fiber cloth obtained in Examples 18 to 20 and Comparative Examples 5 and 6, and Table 8 shows the properties of the carbon fiber cloth.

table

* 1 0 1 蠛锥 Surface average oxygen concentration

# 2 O 2 Freeze-crushed fiber average oxygen concentration

Table 8

* 1 A 1: Outermost surface measured value of 7t * / σ *

* 2 Α 2: π # / σ * ' Industrial applicability

According to the present invention, the reaction heat generated during cyclization or oxidation, which is likely to be stored in a high-density yarn or fabric formed by bundling a large number of single fibers during the flame-resistant treatment of an acrylic fiber, is evaporated vapor or liquid. The heat can be efficiently removed by the heat transfer, and as a result, the flame-resistant fiber and the flame-resistant fiber fabric can be manufactured with extremely high efficiency, and furthermore, the carbon fiber and the graphite fiber can be manufactured stably. .

The oxidized fiber of the present invention has excellent heat resistance and high tensile strength. Further, the flame-resistant fiber fabric of the present invention is excellent in heat resistance and mechanical strength. Accordingly, the flame-retardant fiber and the flame-retardant fiber cloth of the present invention are, for example, fire-resistant cloth, fire-extinguishing cloth, fire-resistant cloth, fire-resistant work clothes, disaster-prevention goods, heat-resistant filler, friction material, cushion material, spatter sheet, aircraft, etc. It can be suitably used for applications such as fire-blocking sheets and cement-reinforcing fibers.

Furthermore, the oxidized fiber of the present invention can be suitably used as a precursor fiber of carbon fiber,

A carbon fiber having a double structure can be provided. In addition, since the flame-resistant fiber is used as a precursor fiber because of its excellent heat resistance and quality, the yield in the carbonization step can be increased to 50 to 65%, and further to 55 to 65%.

The carbon fiber of the present invention has a double structure, and is excellent not only in the fiber direction but also in the non-fiber direction because it has excellent strength in the fiber direction and excellent adhesion to the resin. It can be suitably used as a reinforcing fiber of the material. Specifically, various sports and leisure equipment such as golf shafts, fishing rod rods, rackets and hockey sticks, primary and secondary structural materials for aircraft, seismic civil engineering reinforcement applications, transportation machinery applications such as automobiles and ships, and wind turbines It can be used for general industrial applications such as a speaker and a cone for audio equipment.

In addition, since carbon fiber fabrics have excellent electrical properties and mechanical strength, they can be used for electronic equipment parts such as mobile phones and personal computer housings, electrode base materials for fuel cells, etc. It is useful as a battery electrode material.

Claims

The scope of the claims

1. Elemental analysis · Flame-resistant fiber material whose average oxygen concentration in the fiber measured by oxygen analysis is 0.07 to 0.17.

2. An oxidized fiber material having an average rate of residual nitrile groups in the fiber of 0 to 40% as measured by infrared spectroscopy. .

3. The ratio O 1 / O 2 of the average oxygen concentration O 1 of the fiber surface measured by X-ray photoelectron spectroscopy O 1 to the average oxygen concentration O 2 of the frozen ground fiber measured by X-ray photoelectron spectroscopy is 1.8 Flame-resistant fiber material which is ~ 4.0. '

4. The flame-resistant fiber material according to any one of claims 1 to 3, which has a form of a fabric.

5. The acrylic fiber material is treated at 180 to 300 ° C in the presence of one or more of organic compounds, fluorine compounds, siloxanes, nitrates and nitrites excluding amine compounds. A method for producing a flame-resistant fiber material, which comprises performing a flame-resistant treatment.

6. The method for producing a flame-resistant fiber material according to claim 5, wherein the acrylic fiber material after the flame-resistance treatment is oxidized at 0 to 400 in an oxidizing atmosphere.

7. The flame-resistant fiber material according to claim 5, wherein the acrylic fiber material during the flame-resistance treatment is simultaneously oxidized at 180 to 300 ° C. in an oxidizing atmosphere. Production method.

8. The acrylic fiber material before the flame-proof treatment is treated in an oxidizing atmosphere in the range of 0 to 400 The method for producing a flame-resistant fiber material according to claim 5, wherein the oxidation treatment is performed at a temperature of ° C.

9. Organic compounds other than the amine compound include aromatic compounds, amide compounds, ketone compounds, monoalcohol compounds, alkylene glycol compounds, polyglycol compounds, polyol compounds, ether compounds, ester compounds, sulfone compounds, The method for producing a flame-retardant fiber material according to claim 5, characterized in that it is at least one organic compound selected from a sulfine compound, a nitroxide compound, a nitric compound, a paraffin compound, and a naphthene compound. .

10. The method according to claim 5, wherein the fluorine compound is at least one selected from a perfluoropolyether compound, a chlorine-substituted fluorine compound, and a polyvinylidene fluoride compound. A method for producing the flame-resistant fiber material according to the above.

11. The method for producing a flame-retardant fiber material according to claim 5, wherein the siloxane is at least one selected from a phenylsilicone compound and a polysiloxane compound.

12. The method for producing an oxidized fiber material according to any one of claims 5 to 11, wherein the acryl-based fiber material is an acryl-based fiber bundle.

13. The method for producing a flame-resistant fiber material according to claim 12, wherein the acrylic fiber bundle is subjected to a flame-resistant treatment with a fineness per 1 mm width of 1,000 to 80,000 dtex x mm. .

14. acrylic fiber 500 to a fineness per unit cross-sectional area of the bundle 7, 5 0 0 oxidized fiber according to claim 1 2, as dtex / mm ² to process oxidization and Toku徵. Material production method of .

1 5. Acrylic fiber bundle with draw ratio of 1.1 to 1.7 must be flameproofed The method for producing an oxidized fiber material according to claim 12, wherein:

1 6. The method for producing a flame-resistant fiber material according to any one of claims 5 to 11, wherein the acryl-based fiber material is an acryl-based fiber cloth.

1 7. The ratio A between the outermost surface measurement value A 1 of 7t * Ζσ * and the maximum value A 2 inside the single fiber obtained by measuring the cross section of the single fiber by electron energy loss spectroscopy using a field emission electron microscope A carbon fiber material wherein 1ZA2 is 0.83-0.94.

18. The carbon fiber material according to claim 17, which has a form of a fabric.

1 9. A method for producing a carbon fiber material, comprising subjecting the oxidized fiber material obtained by the production method according to claim 5 to carbonization at 300 ° C. or more and less than 2,000 X in an inert atmosphere.

20. A method for producing a graphite fiber material, wherein the carbon fiber material obtained by the production method according to claim 19 is graphitized in an inert atmosphere at 2,000 to 3,000 ° C.