JP2003239143A - Method for producing graphite fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a graphite fiber having elastic modulus excellent in high degree of processability and having high quality. <P>SOLUTION: This method for producing the graphite fiber is to apply a compound having ≥30 wt.% rate of heating residue in an inert gas atmosphere at 500°C to an untreated fiber and subsequently treat the fiber to be graphitized. <P>COPYRIGHT: (C)2003,JPO

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、毛羽および糸切れ
抑制に優れた黒鉛繊維の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing graphite fiber which is excellent in suppressing fuzz and yarn breakage.

【０００２】[0002]

【従来の技術】従来から、優れた比強度、比弾性率から
炭素繊維を使用した繊維強化複合材料がスポーツ、レジ
ャー、航空・宇宙分野等に広く利用されている。炭素繊
維は通常、フィラメント又はトウの形で製造され、更
に、一方向に引き揃えたシート、テープ、フィラメント
ワインディング、織物、又はチョップドファイバー等に
加工されて使用されている。特に弾性率については、高
弾性率であるほど少量の材料で必要な剛性を発現し、繊
維強化複合材料の薄肉軽量化につながるため、より高弾
性率を有する黒鉛繊維が必要とされている。しかし、高
弾性率を達成しようとすると黒鉛化処理において処理温
度を上げる、緊張下黒鉛化処理する若しくは延伸処理を
行うなどの条件が必要となり、それに伴い繊維束の毛羽
や糸切れが発生し、物性低下並びに品質低下をもたらす
問題が生じていた。2. Description of the Related Art Conventionally, fiber-reinforced composite materials using carbon fibers have been widely used in sports, leisure, aviation / space fields, etc. due to their excellent specific strength and specific elastic modulus. Carbon fibers are usually manufactured in the form of filaments or tows, and are further processed into unidirectionally aligned sheets, tapes, filament windings, woven fabrics, chopped fibers or the like for use. With regard to the elastic modulus, in particular, the higher the elastic modulus, the smaller the amount of material required to develop the required rigidity, which leads to the thinner and lighter weight of the fiber-reinforced composite material. Therefore, graphite fibers having a higher elastic modulus are required. However, in order to achieve a high elastic modulus, it is necessary to raise the treatment temperature in the graphitization treatment, perform a graphitization treatment under tension, or perform a stretching treatment, and accordingly, fluff or yarn breakage of the fiber bundle occurs, There has been a problem that physical properties and quality are deteriorated.

【０００３】従来、これら問題の対策として、例えば、
特公昭６２−２４５２５号公報では黒鉛化処理前に炭素
繊維に水を付与して集束後、黒鉛化処理する方法が提案
がされているが、毛羽の発生を抑制する効果は著しく不
十分であるという問題があった。Conventionally, as measures against these problems, for example,
Japanese Patent Publication No. 62-24525 proposes a method in which water is applied to carbon fibers before graphitization treatment, and after focusing, graphitization treatment is performed, but the effect of suppressing the generation of fluff is remarkably insufficient. There was a problem.

【０００４】また、特公昭６３−５４８０８号公報では
黒鉛化処理前の炭素繊維に分子量１０万以上のポリエチ
レンオキサイド、メチルエーテル化、エチルエーテル化
若しくはヒドロキシエチルエーテル化されたセルロー
ス、又はポリビニルエチルエーテルの水溶液を集束剤と
して付与する方法が提案されている。しかしながら、こ
の方法では黒鉛化処理の初期の段階で集束剤の大部分が
分解消失するため毛羽および糸切れを生じ、黒鉛化処理
の終了時まで繊維束の集束性を維持することができない
という問題点があった。また、集束剤が多量に分解した
ガスで黒鉛炉内が汚染され、強度低下が大きいという問
題があった。Further, in Japanese Patent Publication No. 63-54808, carbon fibers before graphitization treatment of polyethylene oxide having a molecular weight of 100,000 or more, cellulose etherified with methyl ether, ethyl ether or hydroxyethyl ether, or polyvinyl ethyl ether are used. A method of applying an aqueous solution as a sizing agent has been proposed. However, in this method, most of the sizing agent decomposes and disappears in the initial stage of graphitization, resulting in fluff and yarn breakage, and it is not possible to maintain the sizing property of the fiber bundle until the end of the graphitization. There was a point. In addition, there is a problem that the inside of the graphite furnace is contaminated by the gas in which the sizing agent is decomposed in a large amount and the strength is greatly reduced.

【０００５】さらに、特開平６−２６４３１３号公報で
は黒鉛化処理前の炭素繊維に集束剤として例えばエポキ
シ樹脂、ポリウレタン樹脂、ポリエステル樹脂、ポリエ
チレンオキサイド、ポリプロピレンオキサイド、ポリビ
ニルアルコール、ポリ酢酸ビニル、ポリアミド樹脂など
を付与し、３００〜５００℃の空気中で加熱した後、黒
鉛化処理する方法が提案されている。しかしながら、こ
の方法では空気中の加熱や黒鉛化炉内での熱処理初期に
分解飛散して黒鉛化処理の終了時まで繊維束の集束性を
維持することができないため、高弾性率化に限界があっ
た。また該従来技術で黒鉛繊維の毛羽および糸切れを満
足できるレベルにまで低減するためには集束剤を著しく
多量に付着させておく必要があり、コストアップが大き
いという問題点があった。Further, in JP-A-6-264313, carbon fibers before graphitization are used as a sizing agent, for example, epoxy resin, polyurethane resin, polyester resin, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyvinyl acetate, polyamide resin, etc. Has been proposed, followed by heating in air at 300 to 500 ° C., followed by graphitization treatment. However, in this method, since it is not possible to maintain the focusing property of the fiber bundle until the end of the graphitizing treatment by decomposing and scattering in the initial stage of the heat treatment in the air or the heat treatment in the graphitizing furnace, there is a limit to the high elastic modulus. there were. Further, in order to reduce the fuzz and yarn breakage of the graphite fiber to a satisfactory level in the prior art, it is necessary to attach a sizing agent in a remarkably large amount, which causes a problem of a large cost increase.

【０００６】このように従来技術では毛羽や糸切れが少
ない高品位の高弾性率炭素繊維を得ることが困難であっ
た。As described above, it has been difficult to obtain a high-quality high-modulus carbon fiber with less fluff and yarn breakage by the conventional technique.

【０００７】[0007]

【発明が解決しようとする課題】本発明は、かかる従来
技術の背景に鑑み、毛羽および糸切れが少なく高品位を
有し、高弾性率、高強度を発現する黒鉛繊維の製造方法
を提供せんとするものである。SUMMARY OF THE INVENTION In view of such background of the prior art, the present invention does not provide a method for producing a graphite fiber having high quality with less fluff and yarn breakage, high elastic modulus and high strength. It is what

【０００８】[0008]

【課題を解決するための手段】本発明は、かかる課題を
解決するために、次のような手段を採用するものであ
る。すなわち、黒鉛化処理以前の繊維に、５００℃不活
性雰囲気における加熱残さ率が３０重量％以上である化
合物を付与した後、黒鉛化処理することを特徴とする黒
鉛繊維の製造方法である。The present invention employs the following means in order to solve the above problems. That is, it is a method for producing a graphite fiber, which comprises applying a compound having a heating residue rate of 30% by weight or more in an inert atmosphere at 500 ° C. to the fiber before the graphitization treatment and then performing the graphitization treatment.

【０００９】[0009]

【発明の実施の形態】本発明は、前記課題について、鋭
意検討し、黒鉛化処理以前の繊維に５００℃不活性雰囲
気における加熱残さ率が３０重量％以上である化合物を
付与した後、黒鉛化処理してみたところ、かかる課題を
一挙に解決することを究明したものである。BEST MODE FOR CARRYING OUT THE INVENTION The present invention has been earnestly studied on the above-mentioned problems, and after applying a compound having a heating residue rate of 30% by weight or more in an inert atmosphere at 500 ° C. to a fiber before graphitization, the graphitization is performed. As a result of processing, it was clarified that such problems could be solved all at once.

【００１０】本発明においては、黒鉛化処理工程以前の
繊維に５００℃不活性雰囲気における加熱残さ率が３０
重量％以上である化合物が付与されていることが重要で
ある。つまり、加熱残さの多い化合物を繊維に付与する
ことにより炭素繊維の単繊維同士を擬似接着させ、黒鉛
化処理における毛羽および糸切れを抑制するものであ
る。また、より高温度での処理、緊張下での黒鉛化、高
延伸倍率での黒鉛化ができるので繊維の弾性率をより高
めることが可能となる。In the present invention, the fiber before the graphitization treatment has a heating residue rate of 30 at 500 ° C. in an inert atmosphere.
It is important that the compound is added in an amount of not less than wt%. That is, by adding a compound having a large heating residue to the fibers, the single fibers of the carbon fibers are pseudo-bonded to each other, and fluff and yarn breakage during the graphitization treatment are suppressed. Further, since it is possible to carry out treatment at a higher temperature, graphitization under tension, and graphitization at a high draw ratio, it becomes possible to further increase the elastic modulus of the fiber.

【００１１】ここで擬似接着とは、黒鉛化処理終了時ま
では単繊維同士が見かけ上接着し、集束性を有すること
をいい、黒鉛化処理終了後はローラー等との高張力接着
で見かけ上の接着が解除されて、最終物性は目的とする
強度、弾性率を得るものをいう。The term "pseudo-adhesion" as used herein means that the single fibers are apparently adhered to each other until the end of the graphitization treatment and have a sizing property. The final physical properties mean that the desired strength and elastic modulus are obtained after the adhesion of the is removed.

【００１２】かかる化合物は、黒鉛化処理以前の繊維に
付与されるものであるが、熱処理により分解もしくは揮
発し、重量変化するものであると、黒鉛化処理時に、単
繊維同士の接着が不十分となる。５００℃不活性雰囲気
における加熱残さ率が３０重量％以上であることが必要
であり、より好ましくは５０重量％以上、更に好ましく
は６０重量％以上のものである。５００℃不活性雰囲気
における加熱残さ率が３０重量％未満の化合物では従来
の問題を解決できない。尚、加熱残さ率は９５重量％あ
れば本発明の目的には十分である。[0012] Such a compound is applied to the fibers before the graphitization treatment, but if it decomposes or volatilizes by heat treatment and changes in weight, the adhesion between the single fibers is insufficient during the graphitization treatment. Becomes The heating residue rate in an inert atmosphere at 500 ° C. is required to be 30% by weight or more, more preferably 50% by weight or more, and further preferably 60% by weight or more. A compound having a heating residue rate of less than 30% by weight in an inert atmosphere at 500 ° C. cannot solve the conventional problems. A heating residue rate of 95% by weight is sufficient for the purpose of the present invention.

【００１３】５００℃不活性雰囲気における加熱残さ率
は次のようにして求める。かかる化合物を１２０℃で２
時間加熱して絶乾し、約１ｇをアルミニウム皿にとり、
精秤してＷ１とする。窒素雰囲気の電気炉に入れ、室温
から５００℃まで１５℃/分で昇温し、５００℃で５分
間保持した後、素速く取り出して室温の窒素雰囲気ボッ
クス中で冷却後、精秤しＷ２とし下記式で加熱残さ率を
計算する。 加熱残さ率（重量％）＝｛（Ｗ１−Ｗ２）÷Ｗ１｝×１
００ かかる化合物としては、前記加熱残さ率を満たせば特に
限定されるものではなく、液体でもよいし、固体の微粒
子でもよい。固体の微粒子をそのまま付与してもよい
し、溶液、分散液にして付与してもよい。固体の微粒子
の場合は炭素繊維表面に接着するものが好ましい。The heating residue rate in an inert atmosphere at 500 ° C. is determined as follows. 2 such compounds at 120 ℃
Heat for an hour to dry, put about 1g in an aluminum dish,
Weigh precisely W1. Put in an electric furnace in a nitrogen atmosphere, raise the temperature from room temperature to 500 ° C at 15 ° C / min, hold at 500 ° C for 5 minutes, take out quickly, cool in a nitrogen atmosphere box at room temperature, and weigh accurately to W2. The heating residue rate is calculated by the following formula. Heating residue rate (% by weight) = {(W1-W2) ÷ W1} × 1
The compound is not particularly limited as long as it satisfies the heating residue rate, and may be liquid or solid fine particles. The solid fine particles may be applied as they are, or may be applied as a solution or dispersion. In the case of solid fine particles, those that adhere to the carbon fiber surface are preferable.

【００１４】炭素を含む化合物すなわち有機物は炭素繊
維表面に付着されて黒鉛化工程で加熱されればその炭化
物が炭素繊維表面に接着した状態で単繊維同士を擬似的
に接着するため、好ましく用いられる。硼素、珪素以外
の金属類を含む場合は欠陥となり、強度低下の原因とな
ることがある。前記加熱残さ率を満たし、繊維強度への
影響も少ない有機物としては、例えばフェノール樹脂、
ピッチ等が挙げられる。A compound containing carbon, that is, an organic substance, is preferably used because if adhered to the surface of the carbon fiber and heated in the graphitization step, the carbide adheres to the surface of the carbon fiber and pseudo-bonds the single fibers together. . If metals other than boron and silicon are contained, they may become defects and cause a decrease in strength. As the organic substance that satisfies the heating residue rate and has little influence on the fiber strength, for example, phenol resin,
Pitch etc. are mentioned.

【００１５】かかる化合物は、その特性に応じて種々の
方法で黒鉛化前の繊維に付与することができる。なかで
も均一に付与しやすいという点で溶液、あるい分散液と
して黒鉛化前の繊維に付与することが好ましい。かかる
溶液あるいは分散液として使用する液体は、親水性でも
疎水性でもよく、付与する化合物の種類に応じて適宜選
ばれる。扱いやすさから親水性の液体が好ましい。かか
る親水性の液体としては、水、エタノール、プロパノー
ル、イソプロパノール、ブタノール等の１価アルコー
ル、エチレングリコール、プロピレングリコール、ブタ
ンジオールなどの２価アルコール、グリセリンなどの３
価アルコール、アセトンなどのケトン類、蟻酸、酢酸、
プロピオン酸などの酸、テトラヒドロフラン等の環状エ
ーテル、Ｎ−メチルピロリドン、ジメチルスルフォキサ
イドなどが挙げられる。 これらは複数を混合して用い
ても良い。中でも取り扱い性や環境面を考慮すると水を
含む水系液体であることが好ましく、特に純水は好まし
い。The compound can be applied to the fiber before graphitization by various methods depending on its properties. Above all, it is preferable to apply it as a solution or dispersion to the fibers before graphitization because it is easy to apply uniformly. The liquid used as such a solution or dispersion may be hydrophilic or hydrophobic, and is appropriately selected according to the type of compound to be applied. A hydrophilic liquid is preferable because it is easy to handle. Such hydrophilic liquids include water, monohydric alcohols such as ethanol, propanol, isopropanol, butanol, dihydric alcohols such as ethylene glycol, propylene glycol and butanediol, and glycerin.
Dihydric alcohol, ketones such as acetone, formic acid, acetic acid,
Examples thereof include acids such as propionic acid, cyclic ethers such as tetrahydrofuran, N-methylpyrrolidone, and dimethyl sulfoxide. A plurality of these may be mixed and used. Among them, an aqueous liquid containing water is preferable, and pure water is particularly preferable, in consideration of handleability and environment.

【００１６】尚、本発明において、付与化合物による単
繊維同士の擬似接着は単繊維同士に未接着部分を有する
ものが好ましい。単繊維同士全体が強固に接着されてい
ると黒鉛繊維束が剛直になりすぎ屈曲性が低下し、黒鉛
繊維束が折れやすくなるため高次加工が困難となる場合
がある。また、マトリック樹脂等を用いた繊維強化複合
材料において、単繊維間に樹脂浸入が困難となり未含浸
をおこす場合がある。さらに好ましくは点接着である。
このような観点から、例えばフェノール樹脂の硬化微粒
子を水分散して付与する方法が好ましく適用される。か
かる微粒子径は分散性の点から１μｍ以下が好ましく、
０．１〜１μｍであれば本発明の目的には十分である。In the present invention, the pseudo-adhesion between the single fibers by the imparting compound is preferably one in which the single fibers have an unbonded portion. If the whole single fibers are firmly adhered to each other, the graphite fiber bundle becomes too rigid and the flexibility is lowered, and the graphite fiber bundle is easily broken, which may make it difficult to perform higher-order processing. In addition, in a fiber-reinforced composite material using a matrix resin or the like, it may be difficult to infiltrate the resin between single fibers, resulting in non-impregnation. More preferred is point adhesion.
From such a viewpoint, for example, a method in which cured fine particles of a phenol resin are dispersed in water and applied is preferably applied. The particle size is preferably 1 μm or less from the viewpoint of dispersibility,
A thickness of 0.1 to 1 μm is sufficient for the purpose of the present invention.

【００１７】単繊維同士に未接着部分があるかどうか
は、たとえば、繊維束を５ｍｍ長にカットし、ノニオン
系界面活性剤０．２％程度の水中にいれ、マグネチック
スターラーで２００ｒｐｍ程度の緩い撹拌後、濾紙で濾
過し、単繊維に解れていない部分の繊維側面を電子顕微
鏡で観察することによって確認できる。また、分散液中
の粒子系は希薄分散液の水を蒸発させた後、電子顕微鏡
で直径を測定する事によって確認可能である。Whether or not there is an unbonded portion between the single fibers is determined by, for example, cutting the fiber bundle into a length of 5 mm, putting it in water containing about 0.2% of a nonionic surfactant, and gently using a magnetic stirrer at about 200 rpm. It can be confirmed by filtering with a filter paper after stirring and observing the side surface of the fiber which is not disentangled into single fibers with an electron microscope. The particle system in the dispersion can be confirmed by evaporating the water in the dilute dispersion and then measuring the diameter with an electron microscope.

【００１８】本発明に用いる溶液もしくは分散液には必
要に応じて分散剤、塩、ｐＨ調整剤、防腐剤、粘度調整
剤、キレーター等が含まれていても構わない。The solution or dispersion used in the present invention may optionally contain a dispersant, a salt, a pH adjusting agent, an antiseptic, a viscosity adjusting agent, a chelator and the like.

【００１９】またかかる溶液もしくは分散液の付与方法
も特に限定されないが、例えば処理液に被処理繊維をデ
ィップする方法や噴霧する方法などが好ましく適用され
る。The method of applying such a solution or dispersion is not particularly limited, but for example, a method of dipping the fiber to be treated in the treatment liquid or a method of spraying is preferably applied.

【００２０】本発明で用いる加熱残さ率が３０重量％以
上である化合物の付着量は黒鉛化処理以前の繊維に対し
て好ましくは０．１〜５重量％、さらに好ましくは０．
３〜２重量％がよい。付着量が多いと、黒鉛繊維である
単繊維同士の擬似接着が強固となり黒鉛繊維束が剛直に
なりすぎ耐屈曲性が低下し高次加工が困難となることが
ある。また、付与物付着量が少ないと付与した有機物に
よる単繊維同士の擬似接着が少なく、毛羽、糸切れ等の
抑制効果が不十分な場合がある。The amount of the compound having a heating residue rate of 30% by weight or more used in the present invention is preferably 0.1 to 5% by weight, more preferably 0.1% by weight, based on the fiber before the graphitization treatment.
3 to 2% by weight is preferable. If the adhered amount is large, the pseudo-adhesion between the single filaments, which are graphite fibers, becomes strong, the graphite fiber bundle becomes too rigid, and the bending resistance decreases, which may make it difficult to perform higher-order processing. Further, if the amount of the applied substance is small, the pseudo-adhesion between the single fibers due to the applied organic substance is small, and the effect of suppressing fluff, yarn breakage, etc. may be insufficient.

【００２１】本発明では黒鉛化に至る工程は特に限定さ
れるものではない。目的とする性能にもよるが、紡糸工
程により前駆体繊維を得て、その後、耐炎化（熱安定
化、不融化）工程、炭化（炭素化）工程を経て炭素繊維
とし、それをさらに黒鉛化工程で処理することにより黒
鉛繊維を得る方法が好適に用いられる。尚、各工程の処
理温度、昇温速度、処理速度、延伸比、張力などの条件
は目的とする黒鉛繊維の特性によって適宜選択すること
ができる。In the present invention, the steps leading to graphitization are not particularly limited. Depending on the desired performance, a precursor fiber is obtained by a spinning process, and then a flame resistance (heat stabilization, infusibilization) process and a carbonization (carbonization) process are performed to form a carbon fiber, which is further graphitized. A method of obtaining graphite fibers by treating in a step is preferably used. The conditions such as the treatment temperature, the temperature rising rate, the treatment rate, the stretching ratio, and the tension in each step can be appropriately selected according to the characteristics of the target graphite fiber.

【００２２】本発明において、黒鉛化処理以前であれ
ば、どの工程でも繊維に該化合物の付与を行うことがで
きる。特に耐炎化工程以降かつ黒鉛化処理以前の付与が
好ましい。さらに好ましくは炭化工程以降かつ黒鉛化処
理以前の付与である。耐炎化以前であると繊維束の集束
により酸素透過が阻害されムラ焼けを起こす原因となる
場合がある。また、炭化工程以前に付与すると、繊維自
体の円滑な炭素化を阻害し、繊維束の引張強度を低下さ
せる原因となる場合がある。In the present invention, the compound can be added to the fiber at any step before the graphitization treatment. In particular, it is preferably applied after the flameproofing step and before the graphitization treatment. More preferably, it is applied after the carbonization step and before the graphitization treatment. If it is before the flame resistance, the oxygen permeation may be hindered by the convergence of the fiber bundle, which may cause uneven burning. If applied before the carbonization step, the smooth carbonization of the fibers themselves may be hindered and the tensile strength of the fiber bundle may be reduced.

【００２３】本発明に用いる化合物を付与した繊維は、
溶液もしくは分散液として使用した液体を乾燥すること
が工程安定化の観点から好ましい。乾燥温度や時間は特
に限定されるものではなく、溶液もしくは分散液の液体
を除去できる最低限の条件に設定することが好ましい。The fiber provided with the compound used in the present invention is
It is preferable to dry the liquid used as the solution or dispersion from the viewpoint of stabilizing the process. The drying temperature and time are not particularly limited, and it is preferable to set the minimum conditions that can remove the liquid of the solution or dispersion.

【００２４】本発明に用いる前駆体繊維としては、ポリ
アクリロニトリル、レーヨン、リグニン、ポリビニルア
ルコール、ポリアセチレン、ピッチなどを原料とする各
種前駆体繊維が挙げられるが、特にこれらに限定するも
のではない。高強度という点では、ポリアクリロニトリ
ルを原料とした前駆体が好ましく用いられる。前駆体繊
維はフィラメント数１０００〜４８０００が好ましく、
さらには６０００〜２４０００が好ましい。Examples of the precursor fiber used in the present invention include various precursor fibers made of polyacrylonitrile, rayon, lignin, polyvinyl alcohol, polyacetylene, pitch and the like, but are not particularly limited thereto. From the viewpoint of high strength, a precursor made from polyacrylonitrile is preferably used. The number of filaments of the precursor fiber is preferably 1000 to 48000,
Furthermore, 6000-24000 are preferable.

【００２５】前駆体繊維を得るための紡糸方法として
は、原料に応じて湿式紡糸、乾式紡糸、乾湿式紡糸、溶
融紡糸などが挙げられる。操業性の点からは、湿式紡
糸、乾湿式紡糸が好ましく用いられ、乾湿式紡糸がより
好ましい。The spinning method for obtaining the precursor fiber includes wet spinning, dry spinning, dry-wet spinning, melt spinning and the like depending on the raw material. From the viewpoint of operability, wet spinning and dry wet spinning are preferably used, and dry wet spinning is more preferable.

【００２６】さらに、製品目的によっては得られた黒鉛
繊維を仕上げ処理することが好ましい。かかる仕上げ処
理には表面処理やサイジング剤の付与などが含まれる。
かかる表面処理法としては、気相中での加熱、紫外線等
による酸化、液相中で酸化剤を用いた化学的酸化又は水
溶液中で電気化学的手法により酸化する方法などが挙げ
られる。かかる処理により複合材料用補強繊維として用
いる場合の樹脂との親和性、例えば接着性、濡れ性、分
散性等の表面特性を高められる。さらに、サイジング剤
を付与することにより集束性を増し、繊維の取り扱いが
容易となる。黒鉛繊維の形態としては、単糸を２本以上
合わせて撚りをかけて熱処理をする有撚糸、単糸を２本
以上合わせて撚りをかけて熱処理し、その後撚りを解く
解撚糸、実質的に撚りをかけずに熱処理を行う無撚糸な
どいずれにも適用できるが、複合材料の成形性と強度特
性のバランスを考慮すると無撚り糸または解撚糸とする
のが好ましく、さらに、プリプレグなどの中間基材への
加工性の面からは無撚り糸とするのが好ましい。本発明
の製造方法を用いることにより、高弾性率および高強度
の発現が可能となり、優れた特性の黒鉛繊維が提供でき
る。具体的には弾性率が４００ＧＰａ、更には５００Ｇ
Ｐａ以上の黒鉛繊維の提供が可能となる。また強度が４
５００ＭＰａ以上でかつ弾性率が５５０ＧＰａ以上の黒
鉛繊維が提供可能となる。また毛羽が少なく、単繊維間
の適度な接着により耐毛羽性耐擦過性、集束性等が向上
し、高次加工性に優れる黒鉛繊維束を提供することがで
きる。更に、本発明の製造方法により、黒鉛化処理の際
の糸切れも減少するため、工程安定性も改善される。Further, depending on the purpose of the product, it is preferable to finish the obtained graphite fiber. Such finishing treatment includes surface treatment and application of a sizing agent.
Examples of such a surface treatment method include heating in a gas phase, oxidation by ultraviolet rays, chemical oxidation using an oxidant in a liquid phase, or oxidation in an aqueous solution by an electrochemical method. By such a treatment, surface properties such as adhesiveness, wettability, dispersibility, etc. with a resin when used as a reinforcing fiber for a composite material can be enhanced. Further, by imparting a sizing agent, the sizing property is increased and the fibers are easily handled. The form of the graphite fiber is a twisted yarn in which two or more single yarns are combined and twisted for heat treatment, and a untwisted yarn in which two or more single yarns are combined and twisted for heat treatment, and then untwisted, substantially. It can be applied to any non-twisted yarn that is heat-treated without twisting, but in consideration of the balance between the moldability and strength characteristics of the composite material, it is preferable to use a non-twisted yarn or untwisted yarn, and further, an intermediate base material such as prepreg. From the standpoint of processability of the non-twisted yarn, it is preferable to use a twist-free yarn. By using the production method of the present invention, a high elastic modulus and high strength can be exhibited, and a graphite fiber having excellent properties can be provided. Specifically, the elastic modulus is 400 GPa, and further 500 G
It is possible to provide graphite fibers of Pa or more. Also strength is 4
It is possible to provide a graphite fiber having an elastic modulus of 500 MPa or more and an elastic modulus of 550 GPa or more. Further, it is possible to provide a graphite fiber bundle having a small number of fluffs, improved fluff resistance, abrasion resistance, and bunching property due to appropriate adhesion between single fibers, and excellent in high-order processability. Furthermore, the production method of the present invention also reduces yarn breakage during graphitization treatment, thus improving process stability.

【００２７】[0027]

【実施例】以下、実施例により本発明をさらに具体的に
説明する。尚、付与した化合物の加熱残さ率および得ら
れた黒鉛繊維の各種試験結果は表１にまとめて示す。EXAMPLES The present invention will be described in more detail below with reference to examples. Table 1 collectively shows the heating residue rate of the applied compound and various test results of the obtained graphite fiber.

【００２８】本発明における黒鉛繊維の毛羽数、品位、
黒鉛繊維束の引張強度および引張弾性率並びに黒鉛化処
理前の繊維に付与した化合物の加熱残さ率は下記の方法
で測定した。 （１）毛羽数 黒鉛化炉から連続的に出てくる繊維束の毛羽数を１分間
数え、その値を繊維束１ｍ当たりに換算した。 （２）黒鉛繊維束の引張強度および弾性率 ユニオンカーバイト゛社製ＥＬＲ−４２２１を１００重量
部、３フッ化ホウ素モノエチルアミン（ＢＦ₃・ＭＥ
Ａ）を３部、アセトンを４部添加撹拌して樹脂組成物を
得た。この樹脂組成物を黒鉛繊維束に含浸させ、１３０
℃で３５分間硬化させた後、ＪＩＳ Ｒ７６０１に基づ
いて引張試験を行った。 （３）品位 最終工程での繊維束の毛羽数を測定し、目視で判定し
た。毛羽がほとんどなく品位良好なものを○、毛羽がと
きおり見られるが使用可能なものを△、毛羽が多く不良
なものを×とした。 （４）加熱残さ率 ５００℃不活性雰囲気における加熱残さ率は次のように
して求めた。かかる化合物を１２０℃で２時間加熱して
絶乾し、約１ｇをアルミニウム皿にとり、精秤してＷ１
とした。窒素雰囲気の電気炉に入れ、室温から５００℃
まで１５℃/分で昇温し、５００℃で５分間保持した
後、素速く取り出して室温の窒素雰囲気ボックス中で冷
却後、精秤しＷ２とし下記式で加熱残さ率を計算した。 加熱残さ率（重量％）＝｛（Ｗ１−Ｗ２）÷Ｗ１｝×１
００ （実施例１）アクリロニトリル９９．４モル％とメタク
リル酸０．６モル％からなる共重合体を用いて、乾湿式
紡糸方法により０．８デニール、フィラメント数６００
０のアクリル系繊維を得た。得られた繊維束を実質的に
撚りのない状態で２４０〜２８０℃の空気中で、延伸比
１．０５で加熱し、耐炎化繊維に転換し、ついで窒素雰
囲気中３００〜９００℃の温度領域での昇温速度を２０
０℃／分とし１０％の延伸を行った後、１９５０℃まで
焼成し炭素繊維を得た。In the present invention, the number of fluffs and quality of the graphite fiber,
The tensile strength and tensile modulus of the graphite fiber bundle and the heating residue rate of the compound applied to the fibers before the graphitization treatment were measured by the following methods. (1) Number of fluffs The number of fluffs in the fiber bundle continuously coming out from the graphitization furnace was counted for 1 minute, and the value was converted to 1 m of the fiber bundle. (2) Tensile strength and modulus Union Carbide Bu Co. ELR-4221 to 100 parts by weight of the graphite fiber bundles, boron trifluoride monoethyl amine (BF ₃ · ME
3 parts of A) and 4 parts of acetone were added and stirred to obtain a resin composition. A graphite fiber bundle was impregnated with this resin composition,
After curing at 35 ° C. for 35 minutes, a tensile test was performed based on JIS R7601. (3) Quality The number of fluffs in the fiber bundle in the final step was measured and visually determined. Good quality with almost no fluff was evaluated as ◯, fluff that was occasionally seen but usable was evaluated as Δ, and poor fluff was evaluated as x. (4) Heating residue rate The heating residue rate in an inert atmosphere at 500 ° C was determined as follows. The compound is heated at 120 ° C. for 2 hours to be completely dried, and about 1 g is placed in an aluminum dish and precisely weighed to obtain W1.
And Put in an electric furnace in a nitrogen atmosphere, room temperature to 500 ° C
The temperature was raised to 15 ° C./min, and the temperature was kept at 500 ° C. for 5 minutes, then quickly taken out, cooled in a nitrogen atmosphere box at room temperature, accurately weighed as W2, and the heating residue rate was calculated by the following formula. Heating residue rate (% by weight) = {(W1-W2) ÷ W1} × 1
(Example 1) 0.8 denier and 600 filaments by dry-wet spinning method using a copolymer of 99.4 mol% acrylonitrile and 0.6 mol% methacrylic acid
0 acrylic fiber was obtained. The obtained fiber bundle is heated in the air at 240 to 280 ° C. in a substantially twist-free state at a draw ratio of 1.05 to be converted into flame-resistant fibers, and then in a nitrogen atmosphere at a temperature range of 300 to 900 ° C. Heating rate at 20
After stretching at 0 ° C./min and 10%, it was fired up to 1950 ° C. to obtain a carbon fiber.

【００２９】ついで水溶性フェノール樹脂（昭和高分子
（株）社製、ＢＲＬ−２８５４）を水に溶解し０．４重
量％の水溶液を調製し、フェノール樹脂の付着量が炭素
繊維重量に対して０．３重量％になるように、浸漬法に
より炭素繊維束に付与し、２１０℃で乾燥を行った後、
窒素雰囲気中２７００℃の温度で黒鉛化処理を行った。
尚、黒鉛化延伸比は黒鉛化炉出の繊維束の毛羽数を測定
し毛羽数が０〜１個／ｍをキープする範囲の限界延伸比
とし、黒鉛化処理を行い黒鉛繊維を得た。Then, a water-soluble phenolic resin (BRL-2854 manufactured by Showa Highpolymer Co., Ltd.) was dissolved in water to prepare a 0.4% by weight aqueous solution, and the amount of the phenolic resin deposited was relative to the weight of carbon fiber. The carbon fiber bundle was applied to the carbon fiber bundle by a dipping method so as to have a content of 0.3% by weight and dried at 210 ° C.
Graphitization was performed at a temperature of 2700 ° C. in a nitrogen atmosphere.
The graphitization draw ratio was determined by measuring the number of fluffs in the fiber bundle discharged from the graphitization furnace, and setting the limit draw ratio within the range in which the number of fluffs was kept at 0 to 1 / m, and graphitized to obtain graphite fibers.

【００３０】（実施例２）水溶液中の水溶性フェノール
樹脂の濃度を０．６重量％とし、フェノール樹脂の付着
量を炭素繊維に対して０．５重量％になるように炭素繊
維束に付与した以外は実施例１と同様に処理して黒鉛繊
維束を得た。(Example 2) The concentration of the water-soluble phenolic resin in the aqueous solution was set to 0.6% by weight, and the amount of the phenolic resin attached was applied to the carbon fiber bundle so as to be 0.5% by weight based on the carbon fiber. A graphite fiber bundle was obtained in the same manner as in Example 1 except for the above.

【００３１】（実施例３）水溶液中の水溶性フェノール
樹脂の濃度を１．２重量％とし、フェノール樹脂の付着
量を炭素繊維に対して１重量％になるように炭素繊維束
に付与した以外は実施例１と同様に処理して黒鉛繊維束
を得た。(Example 3) The concentration of the water-soluble phenolic resin in the aqueous solution was 1.2% by weight, and the carbon fiber bundle was applied so that the amount of the phenolic resin deposited was 1% by weight based on the carbon fiber. Was treated in the same manner as in Example 1 to obtain a graphite fiber bundle.

【００３２】（実施例４）水溶液中の水溶性フェノール
樹脂の濃度を３．６重量％とし、フェノール樹脂の付着
量を炭素繊維に対して３重量％になるように炭素繊維束
に付与した以外は実施例１と同様に処理して黒鉛繊維束
を得た。(Example 4) The concentration of the water-soluble phenolic resin in the aqueous solution was set to 3.6% by weight, and the amount of the phenolic resin deposited was added to the carbon fiber bundle so that it would be 3% by weight based on the carbon fiber. Was treated in the same manner as in Example 1 to obtain a graphite fiber bundle.

【００３３】（実施例５）水溶液中の水溶性フェノール
樹脂の濃度を６．７重量％とし、フェノール樹脂の付着
量を炭素繊維に対して５．５重量％になるように炭素繊
維束に付与した以外は実施例１と同様に処理して黒鉛繊
維束を得た。(Example 5) The concentration of the water-soluble phenolic resin in the aqueous solution was set to 6.7% by weight, and the amount of the phenolic resin deposited was applied to the carbon fiber bundle so that it would be 5.5% by weight based on the carbon fiber. A graphite fiber bundle was obtained in the same manner as in Example 1 except for the above.

【００３４】（比較例１）化合物を付与しない以外は実
施例１と同様に処理して黒鉛繊維束を得た。(Comparative Example 1) A graphite fiber bundle was obtained in the same manner as in Example 1 except that the compound was not added.

【００３５】（比較例２）ポリウレタン樹脂（第一工業
製薬社製、Ｅ２０００）の濃度が６．０重量％の水溶液
を調製し、ポリウレタン樹脂の付着量が炭素繊維束に対
して３重量％になるように炭素繊維束に付与した以外は
実施例１と同様に処理して黒鉛繊維束を得た。Comparative Example 2 An aqueous solution having a concentration of 6.0% by weight of a polyurethane resin (E2000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was prepared, and the amount of the polyurethane resin deposited was 3% by weight based on the carbon fiber bundle. A graphite fiber bundle was obtained by treating in the same manner as in Example 1 except that the carbon fiber bundle was added as described above.

【００３６】（比較例３）ヒドロキシエチルセルロース
（和光純薬工業社製試薬）の濃度が６．０重量％の水溶
液を調製し、ヒドロキシエチルセルロースの付着量が炭
素繊維束に対して３重量％になるように炭素繊維束に付
与した以外は実施例１と同様に処理して黒鉛繊維束を得
た。(Comparative Example 3) An aqueous solution having a concentration of hydroxyethyl cellulose (reagent manufactured by Wako Pure Chemical Industries, Ltd.) of 6.0 wt% was prepared, and the amount of hydroxyethyl cellulose deposited was 3 wt% based on the carbon fiber bundle. A graphite fiber bundle was obtained in the same manner as in Example 1 except that the carbon fiber bundle was applied.

【００３７】（比較例４）ポリビニルアルコール（和光
純薬工業社製試薬）の濃度が５．０重量％の水溶液を調
製し、ポリビニルアルコールの付着量が炭素繊維束に対
して３重量％になるように炭素繊維束に付与した以外は
実施例１と同様に処理して黒鉛繊維束を得た。(Comparative Example 4) An aqueous solution in which the concentration of polyvinyl alcohol (reagent manufactured by Wako Pure Chemical Industries, Ltd.) was 5.0% by weight was prepared, and the amount of polyvinyl alcohol deposited was 3% by weight based on the carbon fiber bundle. A graphite fiber bundle was obtained in the same manner as in Example 1 except that the carbon fiber bundle was applied.

【００３８】[0038]

【表１】 [Table 1]

【００３９】表１より、黒鉛処理前に何も付与しない比
較例１と対比すると、実施例１は、高延伸黒鉛化が出来
るため黒鉛繊維束の引張弾性率、引張強度は共に高い値
を示した。また、毛羽数は比較例１より少なく、品位も
満足のいくものであった。From Table 1, as compared with Comparative Example 1 in which nothing was added before the graphite treatment, Example 1 shows a high tensile elastic modulus and high tensile strength of the graphite fiber bundle because it is capable of high stretch graphitization. It was Moreover, the number of fluffs was smaller than that in Comparative Example 1, and the quality was also satisfactory.

【００４０】実施例２および３は、毛羽数が実施例１よ
り少なく、黒鉛繊維束の引張弾性率および引張強度は共
に高い値を示し、さらに品位も良好であった。In Examples 2 and 3, the number of fluffs was smaller than that in Example 1, both the tensile modulus of elasticity and the tensile strength of the graphite fiber bundle were high, and the quality was also good.

【００４１】実施例４は、毛羽数が実施例２、３より少
なく、黒鉛繊維束の引張弾性率および引張強度は共に高
い値を示した。また、黒鉛繊維束が若干硬くなったが品
位としては満足のいくものであった。In Example 4, the number of fluffs was smaller than in Examples 2 and 3, and both the tensile elastic modulus and the tensile strength of the graphite fiber bundle were high. Moreover, the graphite fiber bundle was slightly hardened, but was satisfactory in terms of quality.

【００４２】実施例５は、毛羽数が実施例２、３より少
なく、黒鉛繊維束の引張弾性率は高い値を示した。しか
し、黒鉛繊維束が硬くなり、引張強度が実施例２，３に
比べて低かった。In Example 5, the number of fluffs was smaller than in Examples 2 and 3, and the tensile elastic modulus of the graphite fiber bundle showed a high value. However, the graphite fiber bundle became hard and the tensile strength was lower than in Examples 2 and 3.

【００４３】比較例１〜４は、黒鉛化処理で毛羽が発生
し易いため、低延伸黒鉛化を余儀なくされ、そのため引
張弾性率が低く、また、黒鉛化処理後工程で毛羽が発生
しやすく品位も満足できるものではなかった。In Comparative Examples 1 to 4, since fluff is easily generated in the graphitization treatment, low stretch graphitization is unavoidable. Therefore, the tensile elastic modulus is low, and fluff is easily generated in the step after the graphitization treatment. Was not satisfactory either.

【００４４】[0044]

【発明の効果】本発明によれば、高弾性率および高強度
の発現が可能となり優れた特性の黒鉛繊維が提供でき
る。耐毛羽性、耐擦過性、集束性に優れた高品位の黒鉛
繊維の製造方法を提供することができる。EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a graphite fiber having excellent characteristics because it is possible to exhibit high elastic modulus and high strength. It is possible to provide a method for producing a high-quality graphite fiber having excellent fluff resistance, abrasion resistance, and bundling property.

───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4G046 EA02 EA03 EB02 EB04 EC01 4L033 AB01 AC11 AC15 BA02 CA34 CA70 4L037 CS04 FA07 FA10 PG02    ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4G046 EA02 EA03 EB02 EB04 EC01                 4L033 AB01 AC11 AC15 BA02 CA34                       CA70                 4L037 CS04 FA07 FA10 PG02

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】黒鉛化処理以前の繊維に、５００℃不活性
雰囲気における加熱残さ率が３０重量％以上である化合
物を付与した後、黒鉛化処理することを特徴とする黒鉛
繊維の製造方法。1. A method for producing a graphite fiber, which comprises applying a compound having a heating residue rate of 30% by weight or more in an inert atmosphere at 500 ° C. to the fiber before the graphitization treatment and then performing the graphitization treatment. 【請求項２】前記化合物の黒鉛化処理以前の繊維に対す
る付着量が、０．１重量％〜５重量％である請求項１記
載の黒鉛繊維の製造方法。2. The method for producing a graphite fiber according to claim 1, wherein the amount of the compound attached to the fiber before the graphitization treatment is 0.1% by weight to 5% by weight. 【請求項３】前記化合物が有機物であることを特徴とす
る請求項１または２に記載の黒鉛繊維の製造方法。3. The method for producing a graphite fiber according to claim 1, wherein the compound is an organic substance. 【請求項４】前記化合物が、フェノール樹脂またはピッ
チである請求項１〜３のいずれかに記載の黒鉛繊維の製
造方法。4. The method for producing a graphite fiber according to claim 1, wherein the compound is a phenol resin or pitch. 【請求項５】前記化合物が、溶液または分散液として黒
鉛化処理以前の繊維に付与されることを特徴とする請求
項１〜４のいずれかに記載の黒鉛繊維の製造方法。5. The method for producing a graphite fiber according to claim 1, wherein the compound is applied as a solution or dispersion to the fiber before the graphitization treatment.