JPS60126323A - Infusibilization of pitch fiber - Google Patents

Abstract

PURPOSE:To infusibilize a pitch fiber efficiently, preventing the welding and combustion of the fiber, by melt-spinning a pitch, and treating the obained fiber in a gaseous atmosphere composed of oxygen and nitrogen and meeting a specific condition. CONSTITUTION:A fiber obtained by the melt-spinning of pitch is infusibilized in a gaseous atmosphere composed of oxygen and nitrogen, prefrably in a batch furnace or semicontinuous furnace. The oxygen concentration of the atmosphere is adjusted higher at the initial stage of the infusibilization (preferably >=30%) and lower at the latter stage (preferably <=15%). The flow rate of the gas passing through the fiber layer in the chamber is preferably adjusted to 0.02-3m/ sec and the rate of the temperature increase is made higher at the latter stage of infusibilization.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は石炭系ピッチ、石油系ピッチ、有機物焼成ピッ
チなどのピッチ類を溶融紡糸して、得られる繊維を、酸
化雰囲気中で加熱して不融化し、次いで不活性雰囲気中
で炭化、あるいは必要に応じて黒鉛化する事によって炭
素繊維を製造する方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention involves melt-spinning pitches such as coal-based pitch, petroleum-based pitch, and organic calcined pitch, and heating the resulting fibers in an oxidizing atmosphere to make them infusible. The present invention relates to a method for producing carbon fibers by carbonizing the carbon fibers in an inert atmosphere or, if necessary, graphitizing the carbon fibers.

従来技術 ピッチ類を原料とする炭素繊維は、レーヨン系や、アク
リルニトリル系等の炭素繊維に較べて炭化収率が高く、
低コストであり、又原料がメンフェースピッチやブリメ
ンフェースピッチ状であるときは、これらに較べて黒鉛
化性が優れ、弾性率が高い特長がある。Conventional technology Carbon fibers made from pitches have a higher carbonization yield than rayon-based or acrylonitrile-based carbon fibers.
It is low cost, and when the raw material is in the form of menface pitch or brimenface pitch, it has excellent graphitization properties and high elastic modulus compared to these.

ピッチ系炭素繊維を製造する方法はピッチ類を加熱溶融
して紡糸機から押し出し、必要に応じて集東して、まず
ピッチ繊維を得、これを空気などの酸化性雰囲気下で最
高２００〜４００°Ｃ伺近に加熱して不融化して不融化
繊維とし、次いで炭化炉内で窒素などの不活性ガス雰囲
気中で例えばａ　ｏ　ｏ　’ｃ以上に加熱して炭化し、
さらには２０００〜３０００°Ｃの高温で処理して黒鉛
化して炭素繊維を得る。ピッチ繊維は炭化過程で構成分
子が環化、巨大化し、−＋ｉ面構造が発達して高強度、
高弾性となり、これにより織物用や、複合材料の補強改
質用として特セ１を発揮しうる。The method for producing pitch-based carbon fibers is to heat and melt pitches, extrude them from a spinning machine, collect them if necessary, and obtain pitch fibers, which are then heated to a maximum density of 200 to 400% in an oxidizing atmosphere such as air. The fibers are made infusible by heating to a temperature close to 10°C, and then heated to a temperature of, for example, ao o 'c or higher in a carbonization furnace in an inert gas atmosphere such as nitrogen to carbonize.
Furthermore, it is treated at a high temperature of 2000 to 3000°C to graphitize to obtain carbon fiber. During the carbonization process, the constituent molecules of pitch fibers become cyclized and enlarged, and a −+i-plane structure develops, resulting in high strength and
It has high elasticity, which makes it particularly useful for textiles and for reinforcing and modifying composite materials.

ピンチ系炭素繊維がｆｊす記した様な特長を発揮する為
にはこの様な処理工程において繊維が損われるＩｉｉな
く能率的に処理される事が必要である。この様な観点か
ら見る場合ピンチ系炭素繊維はボリア〃リルニトリル系
に較べて−っの大きな弱点がある。それはＬ紀要融化が
工業技術的に見てきわめて難しい作業であるへにある。In order for the pinch type carbon fiber to exhibit the characteristics described in fj, it is necessary that the fiber be processed efficiently in such processing steps without damaging the fiber. From this point of view, pinch type carbon fibers have a major weakness compared to boriyal nitrile type carbon fibers. The reason for this is that converting L bulletins is an extremely difficult task from an industrial technology perspective.

元来ピンチはコールタールや石油等の重質油類の一留分
であるから２００〜４００°Ｃで容易に軟化する。ピッ
チを溶融紡糸したピッチ＃＃維も当然熱溶融性であるか
らこのまま炭化しようとしても溶融して繊維形状を維持
し得ない。この為に炭化に先立って空気などの酸化性雰
囲気中で最高２００〜４００°Ｃ伺近で、酸素を３〜１
０％伺加し重合させ不融化する。分子量の低い熱溶融性
の物質を熱不溶性にするこの過程で熱を加えながら酸化
しなければならない点に非常な困難性が存在する。Originally, pinch is a distillate of heavy oils such as coal tar and petroleum, so it easily softens at 200 to 400°C. Pitch ## fibers obtained by melt-spinning pitch are naturally heat-fusible, so even if you try to carbonize them as they are, they will not melt and maintain their fiber shape. For this reason, prior to carbonization, 3 to 1
Add 0% to polymerize and make it infusible. In this process of making a heat-melting substance with a low molecular weight heat-insoluble, it is extremely difficult to oxidize it while applying heat.

それは不融化過程におけるピンチ繊維の軟化融着と反応
の暴走による燃焼である。This is due to the softening and fusion of pinched fibers during the infusibility process and combustion due to runaway reaction.

ポリアクリルニトリル系炭素繊維も炭化に先立って原繊
帷を酸化する耐炎化と呼ばれる処理を施すが、これは既
に高分子化している物質の酸化処理でありピッチ系に較
べて遥かに容易である。Prior to carbonization, polyacrylonitrile carbon fibers are also subjected to a process called flameproofing, which oxidizes the raw fiber, but this is an oxidation process for substances that have already become polymers, and is much easier than pitch-based fibers. .

さて不融化過程における困難は既に述べた如くピッチ繊
維の加熱酸化における繊維どうしの軟化融着と特に高温
イ１近で起り易い反応の暴走による燃焼にあるがこれら
は次の様なメカニズムにもとすいて引き起される。ピッ
チ繊維の不融化で最も多く用いられる酸化剤は空気であ
るがピッチ繊維をその軟化温度よりも遥かに低い温度で
長時間かけて徐々に酸化して不融化するにおいては、ユ
ニ記の様な問題は生じない。しかしそれでは反応が遅く
１．業的には成り立たないので出来るだけ高い温度で速
やかに反応を進める必要がある。通常は軟化点を若１Ｆ
回る温度を選んで不融化をスタートし、酸化が進むにつ
れピッチ繊維の融着温度が一ヒｌｊ１するに応じて次第
に反応温度を上げる車により極力反応完結迄の時間を短
くしようとしている。Now, as mentioned above, the difficulties in the infusibility process are due to the softening and fusion of the fibers during thermal oxidation of the pitch fibers, and the combustion caused by runaway reactions that tend to occur especially near high temperatures.These are caused by the following mechanism. It is then brought up. The most commonly used oxidizing agent for making pitch fibers infusible is air, but to gradually oxidize and make pitch fibers infusible at a temperature much lower than its softening temperature over a long period of time, it is necessary to use a method such as Uni-ki. No problems arise. However, this would result in a slow response.1. Since this is not commercially viable, it is necessary to proceed with the reaction as quickly as possible at as high a temperature as possible. Usually the softening point is 1F
The aim is to shorten the time required to complete the reaction as much as possible by selecting a temperature at which the process is to start infusibility, and as the oxidation progresses, the reaction temperature is gradually increased as the pitch fiber's fusion temperature increases.

しかしこれは反応温度として融着ぎりぎりの所を選ぶの
でピア、チ繊維の種類や、ピッチ繊維がマスとして容器
内で処理される様な場合の繊維の存在状態によっては往
々にして融着に至らしめる場合か多い。また能率を」二
げる為にピッチ繊維を多量に処理しようとする場合繊維
の酸化にもとすく反応熱の除去がうまくゆかないときは
繊維間に熱が前ｈＪ’ｔ　Ｌ、て局部的に異常昇温して
ついに燃焼に至ることがある。However, since the reaction temperature is chosen at the very edge of fusion, depending on the type of pitch fibers and the state of existence of the fibers when pitch fibers are processed in a container as a mass, fusion may not occur. There are many cases of tightening. In addition, when processing a large amount of pitch fibers to increase efficiency, the fibers tend to oxidize, and if the reaction heat is not removed successfully, heat is generated between the fibers and locally. The temperature may rise abnormally and eventually lead to combustion.

ピンチ繊維の不融化反応に関しては例えば時分１１１３
４８−４２８９８　号に窒素の酸化物やＳ０３、ハロゲ
ンの如き反応性気体を使う方法や特公昭５１−１３２５
１号公報に酸素高濃度雰囲気で処理したのち酸素と塩化
水素などの酸を共用して反応を速める方法が提案されて
いるが本発明の意図する融着を防ぎつつ反応速度を維持
し、かつ処理過程における反応の暴走による燃焼を防ぐ
方法に関するものでは無く、しかもいずれも有害物質を
使用するので工程の管理や排ガスの処理に特別な工夫を
必要とする。Regarding the infusibility reaction of pinch fibers, for example, time 1113
No. 48-42898 describes a method using reactive gases such as nitrogen oxides, S03, and halogens, and Japanese Patent Publication No. 51-1325.
No. 1 proposes a method of processing in an oxygen-rich atmosphere and then using oxygen and an acid such as hydrogen chloride to speed up the reaction. This does not concern methods for preventing combustion due to runaway reactions in the treatment process, and since all of them use hazardous substances, special measures are required for process management and exhaust gas treatment.

発明の目的 本発明はピッチ系炭素繊維製造過程における上記の様な
融着あるいは燃焼問題を解決する方法を提供するもので
ある。OBJECTS OF THE INVENTION The present invention provides a method for solving the above-mentioned fusion or combustion problems in the pitch-based carbon fiber manufacturing process.

発明の構成・作用 その骨子とするところはピッチを溶融紡糸し、紡出され
た短い、あるいは連ｋ）″じしたピッチ繊維を不融化、
炭化して炭素繊維を製造する力が４において、不融化雰
囲気として酸素および窒素より成るガスを使用し不融化
の進行につれてその組成を調整すること、すなわち、不
融化初期には酸素濃度を高く、不融化後期には低くする
ことを特徴とするピッチ繊維の不融化方法にある。Structure and operation of the invention The gist of the invention is to melt-spun pitch, infusible the spun short or continuous pitch fibers,
In step 4 of carbonization to produce carbon fibers, a gas consisting of oxygen and nitrogen is used as the infusible atmosphere and the composition is adjusted as the infusibility progresses, that is, the oxygen concentration is high at the beginning of the infusibility, A method for infusibility of pitch fibers is characterized in that the pitch fibers are made low in the latter stage of infusibility.

本発明が酸素と窒素から成るカスを利用するのはベース
カスどじで最も安価な醇化剤である空気を出来るだけ利
用しようとするものである。The reason why the present invention uses scum consisting of oxygen and nitrogen is to use air, which is the cheapest solubilizing agent, as much as possible as a base scum.

ただ空気だけによる場合は前記の様な問題が生しるため
これに酸素富化あるいは窒素稀釈の手段を伺加する。ピ
ッチ繊維としては短繊維あるいは連続繊Ｍ［を問わない
。また不融化方法としては繊Ｍ［を通気孔のある容器に
入れて最高２００〜４００℃迄バッチ式あるいは半連続
、連続式に処理する方法また繊維を一ロール駆動して処
理する方法に適用出来る。これらにおいてピッチ繊維は
まず軟化点より数面〜数ＩＯ度低い温度から酸素・窒素
を含むカスと接触するが、酸素濃度を空気よりも高くし
ておくと、繊維の酸化反応速度は酸素分圧の０．５〜１
．０乗に比例するから空気の場合に較べてより速い反応
速度が得られる。あるいは空気での反応速度を基憎とし
て同じ時間で処理を完結しようとするときより低い温度
で反応を進める事が出来るりけであり、繊維の融着問題
に対して安全サイドで容易な処理が出来る。However, if only air is used, the above-mentioned problems will occur, so oxygen enrichment or nitrogen dilution means will be added. The pitch fibers may be short fibers or continuous fibers. In addition, the infusible method can be applied to a method in which the fiber M is placed in a container with ventilation holes and treated in a batch, semi-continuous, or continuous manner at a maximum temperature of 200 to 400°C, or a method in which the fiber is processed by driving one roll. . In these processes, the pitch fibers first come into contact with scum containing oxygen and nitrogen at a temperature several to several IO degrees lower than their softening point, but if the oxygen concentration is set higher than that of air, the oxidation reaction rate of the fibers is reduced by the oxygen partial pressure. 0.5~1
．． Since it is proportional to the 0th power, a faster reaction rate can be obtained compared to the case of air. Alternatively, it is possible to proceed with the reaction at a lower temperature than when trying to complete the process in the same time based on the reaction speed in air, and it is a safe and easy process to solve the problem of fiber fusion. I can do it.

表−１に軟化点２００℃のピッチから製造した１５ルの
ピッチ繊維を使用して、酸素濃度１０％、約２１％（空
気）、４０％のときの不融化反応速度を示した。Table 1 shows the infusibility reaction rate at oxygen concentrations of 10%, about 21% (air), and 40% using 15L pitch fibers made from pitch with a softening point of 200°C.

表−１ピッチ繊維の不融化に おける酸素伺加速度 同じ反応速度を得るのに酸素濃度４０％のときは、空気
のときより３０°Ｃは低い温度が選べることが判る。Table 1: Oxygen accelerating rate during infusibility of pitch fibers It can be seen that when the oxygen concentration is 40%, a temperature 30°C lower can be selected than when using air to obtain the same reaction rate.

特に不融化においては、反応初期には採すラる反応温度
レベルが最も低くならざるを得す反応時間がかかるとこ
ろであるから本発明の様に初期速度か高められ安全サイ
ドで処理出来るメリットは大きい。酸素濃度としては空
気濃度より高いところが任意に選べるが工業的に顕著な
効果をめるならば３０％程度以上とするのが望ましい。Particularly in the case of infusibility, the reaction temperature level adopted at the beginning of the reaction must be the lowest and the reaction time is required, so the advantage of the present invention is that the initial speed can be increased and the process can be carried out on the safe side. . The oxygen concentration can be arbitrarily selected to be higher than the air concentration, but if industrially significant effects are to be achieved, it is preferably about 30% or more.

反応が進むにつれて反応温度を高める事が出来速度が１
−げられるので酸素濃度を落してゆく事が出来る。As the reaction progresses, the reaction temperature can be increased, increasing the speed by 1.
-The oxygen concentration can be lowered.

勿論酸素富化の効果は反応が進んだ段階でも発現される
ので最後迄空気より高い濃度で速やかに反応：を終らせ
る事も出来るが、酸素費用節減の為にある程度例えば目
標とする酸素付加量の５０％程度が伺加した後は空気濃
度で処理するのも一方法である。Of course, the effect of oxygen enrichment is manifested even at a stage where the reaction has progressed, so it is possible to finish the reaction quickly at a higher concentration than air, but in order to reduce oxygen costs, it is necessary to set a certain amount of oxygen, for example, the target amount of oxygen added. One method is to treat with air concentration after about 50% of the amount has been added.

また本発明者らのｒｆｌＬ察によればピッチ繊維の不融
化においては巾に酸化反応のみならず高温域においては
ピッチ分子そのものの熱重縮合反応も少なからず’＃ｒ
　’ｊ、Ｌ／ていると考えられる。Furthermore, according to the rflL observations of the present inventors, in the process of making pitch fibers infusible, there is not only an oxidation reaction, but also a thermal polycondensation reaction of the pitch molecules themselves in the high temperature range.
'j, L/ is considered to be.

第１図に軟化点１８０℃のピッチから製造した直径１３
終のピッチ繊維を使用して、不融化の際の最終到達温度
を変化させた場合の不融化ビ・ンチ繊維の融着温度に対
する不融化温度の効果を示した。Diameter 13 manufactured from pitch with a softening point of 180°C is shown in Figure 1.
The effect of the infusibility temperature on the fusion temperature of the infusible pitch fiber was shown when the final temperature reached during infusibility was varied using the final pitch fiber.

図中の直線に記された温度はピッチ不融化の際の最終到
達温度を示す。The temperature drawn on the straight line in the figure indicates the final temperature reached during pitch infusibility.

この場合の融着温度とは、不融化したピッチ繊維を一定
温度の熱板上に載せその形状を拡大鏡で観察して繊維が
熱変形を示す最低温度とした。The fusion temperature in this case was defined as the lowest temperature at which the fibers exhibited thermal deformation by placing the infusible pitch fibers on a hot plate at a constant temperature and observing their shape with a magnifying glass.

第１図かられかるように、同じ酸素伺加砥であっても不
融化反応末期の到達温度が高い方が融着温度が高くなり
、次工程の炭化作業が容易になる。この様な事から考え
ると不融化作業はピッチやその繊維の存在状態に応じて
温度と時間の保持が必要となるわけであるが、この様に
高い温度が必要な場合に不融化の後期においても空気濃
度やそれ以上の酸素濃度の雰囲気を保つのはピッチ繊維
の燃焼を招き易くする。この様な場合は雰囲気を窒素で
稀釈して酸化反応を抑えながら熱重合を促進すれは繊維
を燃焼する事なく不融化を完結させる事が出来、この間
必要な温度迄の昇温速度を高くとることも出来る。従っ
て不融化後期の酸素濃度としては空気濃度以下好ましく
は１５％以下に下げるのが望ましい。酸素濃度を全く　
０とするのはこれは炭化作業に属するので不融化反応が
完結１７てから１采られる手順である。As can be seen from FIG. 1, even when using the same oxygen-added abrasive, the higher the temperature reached at the end of the infusibility reaction, the higher the fusion temperature, which facilitates the carbonization work in the next step. Considering this, the infusibility work requires maintaining the temperature and time depending on the state of the pitch and its fibers, but when such high temperatures are required, it is necessary to maintain the temperature and time in the later stages of infusibility. Maintaining an atmosphere with an air concentration or an oxygen concentration higher than that can easily lead to combustion of pitch fibers. In such cases, it is possible to complete infusibility without burning the fibers by diluting the atmosphere with nitrogen to promote thermal polymerization while suppressing the oxidation reaction, and during this time the rate of temperature rise to the required temperature is kept high. You can also do that. Therefore, it is desirable to lower the oxygen concentration in the latter stage of infusibility to below the air concentration, preferably below 15%. no oxygen concentration
The reason why it is set as 0 is that since this belongs to the carbonization operation, one pot is made after the infusibility reaction is completed.

以］−述べた本発明の方法はピッチ繊維の種々の存在形
態に適用出来るが、ピッチ繊維をまとめて通気孔を有す
る容器に収容し多量処理して生産性を１−げようとする
場合には特に繊維の重なりが多くなり融着や反応熱蓄積
による燃焼の危険性が高くなってくるのでこれを回避す
る手段として本発明は極めて有効な方法となる。その様
な場合炉内で容器が１段でなく２段以上に積み重ねた方
が炉の空間利用率が」ニリさらに能率的であるが積み上
げ段数が増える程気流の乱れ、繊維収容状態のばらつき
等が増え管理調整されてない雰囲気下での操業が難しく
なるので本発明の方法の重要性が増す。Although the method of the present invention described above can be applied to various forms of existence of pitch fibers, it is applicable when pitch fibers are collectively stored in a container with ventilation holes and processed in large quantities to increase productivity. In particular, the fibers overlap more and the risk of combustion due to fusion and accumulation of reaction heat increases, so the present invention is an extremely effective method to avoid this. In such cases, it is more efficient to stack the containers in two or more layers instead of one layer in the furnace, but the space utilization rate of the furnace is more efficient, but as the number of stacked containers increases, the airflow becomes turbulent, and the state of fiber accommodation tends to vary. This increases the importance of the method of the present invention as it becomes difficult to operate in an uncontrolled atmosphere.

本発明の方法は不融化反応の進行につれて酸素及び窒素
濃度を調整する点から完全な連続炉よりもパンチあるい
は容器に収められた繊維が温度で分割された複数室から
成る炉ど間歇的に稼動してゆく半連続炉の方が雰囲気の
制御性が良くより確実に効果を発揮させる事が出来る。In order to adjust the oxygen and nitrogen concentrations as the infusibility reaction progresses, the method of the present invention operates intermittently in a furnace consisting of multiple chambers in which fibers housed in punches or containers are divided according to temperature, rather than a completely continuous furnace. Semi-continuous furnaces have better control over the atmosphere and can more reliably demonstrate their effectiveness.

その実施においては容器内の繊維層を通して雰囲気ガス
を強制的に通してその速度調整を行うとより効果が大き
い。通風速度としてはｍ＃が飛散したり乱れたりしない
範囲で大きい程良いが通常０．０２ｍ　／秒〜３ｍ／秒
程度が適当である。In this case, it is more effective to force the atmospheric gas through the fiber layer in the container and adjust its speed. As for the ventilation speed, the higher m# is, the better, as long as it does not cause scattering or turbulence, but usually about 0.02 m/sec to 3 m/sec is appropriate.

実施例１゜ 直径　１００＋ｎｍの流通管式熱風循環反応器に、軟化
点２００°Ｃのピッチを溶融紡糸して製造した直径１５
にの連続ピッチ繊維を嵩密度５０ｇ／文で７８．５’ｇ
ずつ３段積みで充填した。Example 1 A pitch tube with a diameter of 15 mm was produced by melt-spinning pitch with a softening point of 200°C in a flow tube type hot air circulation reactor with a diameter of 100+ nm.
The continuous pitch fiber has a bulk density of 50g/text and is 78.5'g.
Each container was filled in three layers.

使用しｆこ反応器の全空間容積は８．４文であった。The total space volume of the reactor used was 8.4 cm.

これに酸素濃度が４５％になる様に酸素を富化した空気
を　１４０℃から　ｌ’Ｃ／分で昇温しっつ、繊維層を
通過するガス速度が０．５ｍ／秒になる様な速さで下段
から上段に向けて通した。２１０℃からは酸素の富化を
止め系内に残留するガスの循環だけとし２１０°Ｃ〜２
５０°Ｃの間は昇温速度２℃／分１次いで２５０°Ｃか
らは昇温速度を３°Ｃ／分に上げ３００℃に達してさら
にその温度２０分間維持した。Oxygen-enriched air was then heated from 140°C at a rate of 1'C/min so that the oxygen concentration was 45%, and the gas velocity passing through the fiber layer was 0.5m/s. I passed from the bottom to the top with speed. From 210°C, oxygen enrichment is stopped and only the gas remaining in the system is circulated.
During the period of 50°C, the heating rate was 2°C/min, and from 250°C, the heating rate was increased to 3°C/min until reaching 300°C, and the temperature was maintained for an additional 20 minutes.

冷却後循環カス中の酸素濃度は８．３％に丁っておリイ
ＪＩられたピッチ繊維には酸素が６．０％付加し、その
融着渦電は４００°Ｃを越え、繊維の融着や燃焼は無く
、不融化されており　３００°Ｃからスタートとする炭
化処理を行うのに全く問題は無かった。After cooling, the oxygen concentration in the circulating waste was 8.3%, and 6.0% oxygen was added to the JI pitch fibers, and the fusion eddy current exceeded 400°C, causing the fibers to melt. There was no deposition or combustion, and it was infusible, so there were no problems at all when carrying out carbonization treatment starting at 300°C.

比較例として実施例１と同様の条件で使用したカスとし
て畠萌空気濃度で実施したものは、１ｊられたピンチ繊
維には６．１％の酸素が付加したが不融化途中で繊維の
融着が生じて脆くなり、使用に而１えなくな、っていた
。As a comparative example, the waste was used under the same conditions as in Example 1 and carried out at a Hatakemo air concentration. Although 6.1% oxygen was added to the pinched fibers, the fibers were fused during infusibility. It became brittle and unusable.

また他の比較例として常時酸素濃度４５％で実施したも
のは、　２７０　’Ｃ！で最」―段が燃焼してしまった
。In addition, as another comparative example, the test was conducted at a constant oxygen concentration of 45%. The stage burned out.

実施例２ 軟化点２０５°Ｃのピッチを溶融紡糸したピッチ繊＃ｆ
３２０ｇを底面２００ｍｍ角、深さ５００＋ｎｍの通気
孔を有する容器に充填密度２０ｇ／ｌで充填した。この
容器を低温から高温に順次温度がつけられている６つの
炉室から構成される不融化炉の各室に各３０分ずつ滞留
させて不融化を行った。Example 2 Pitch fiber #f obtained by melt-spinning pitch with a softening point of 205°C
320 g was packed at a packing density of 20 g/l into a container having a 200 mm square bottom and a vent hole 500+ nm deep. This container was allowed to remain in each chamber of an infusibility furnace consisting of six furnace chambers, each of which was heated sequentially from low to high temperature, for 30 minutes to effect infusibility.

各室には酸素と窒素から成るガスを繊維層の上から下に
　２．０ｍ　／秒の速度で通気した。各室のカス中の酸
素濃度及び温度は繊維収納容器人口側からそれぞれ５０
％、１５０°Ｃ；４０％、１７０℃；３０％。A gas consisting of oxygen and nitrogen was passed through each chamber from the top to the bottom of the fiber layer at a rate of 2.0 m/sec. The oxygen concentration and temperature in the waste in each chamber are 50% from the population side of the fiber storage container.
%, 150°C; 40%, 170°C; 30%.

１９５°Ｃ；　２０％、２３０°Ｃ：１０％、２８０°
０．　４％。195°C; 20%, 230°C: 10%, 280°
0. 4%.

３５０°Ｃ；に保持した。不融化炉を出たピッチ繊維に
は酸素が７．０％付加しその融着温度は　４００°Ｃを
越え、繊維の融着や燃焼は無く不融化されており３５０
°Ｃからスタートする炭化処理を行うのに全く問題は無
かった。It was maintained at 350°C. 7.0% oxygen is added to the pitch fibers leaving the infusibility furnace, and the fusing temperature exceeds 400°C, and the fibers are infusible without fusing or burning.
There were no problems at all in carrying out the carbonization process starting at °C.

比較例として実施例２と同様の条件て使用したガスとし
て各室とも空気で実施したものは取り出した繊維が融着
していた。また各室４０％の酸素濃度で実施したものは
第５室で燃焼した。As a comparative example, when air was used in each chamber under the same conditions as in Example 2, the fibers taken out were fused. In addition, when the experiment was conducted with an oxygen concentration of 40% in each chamber, combustion occurred in the fifth chamber.

発明の効果 以上詳述したごとく本発明方法によれば繊維の融着や燃
焼は無く不融化され、炭化処理を行うのに全く問題は無
かった。Effects of the Invention As detailed above, according to the method of the present invention, the fibers were made infusible without fusion or combustion, and there were no problems at all in carrying out the carbonization treatment.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、不融化ピッチ繊維の融着温度に対する小融化
温度の影響を示す説明図である。 ４１１ｆ訂出願人　新ｆ−１，４，：製鐵株弐會社（は
が２名）代　理　人　ｊｒ理士　井　−に　雅　土弟１
図 面艷棄イ寸方〇量FIG. 1 is an explanatory diagram showing the influence of the small melting temperature on the melting temperature of infusible pitch fibers. 411f revision applicant New F-1, 4: Steel Corporation Nikaisha (two people) Agent Jr.
Discard drawings, dimensions, quantity

Claims (5)

【特許請求の範囲】[Claims] （１）ピンチを溶融紡糸し紡出されたピッチ＃＃維を不
融化、炭化して炭素繊維を製造する方法において、不融
化雰囲気として酸素および窒素より成るガスを使用し酸
素濃度を不融化初期には高く後期には低くすることを特
徴とするピッチ繊維の不融化方法。(1) In the method of manufacturing carbon fiber by melt-spinning a pinch and infusible and carbonizing the spun pitch ## fiber, a gas consisting of oxygen and nitrogen is used as an infusible atmosphere, and the oxygen concentration is reduced at the initial stage of infusibility. A method for infusibility of pitch fibers, which is characterized in that the temperature is high in the early stages and the pitch fibers are low in the late stages. （２）酸素濃度を不融化初期には３０％以−ヒ、後期に
は１５％以下にする特許請求の範囲第（１）項記載のピ
ッチ繊維の不融化方法。(2) The method for infusibility of pitch fibers according to claim (1), wherein the oxygen concentration is set to 30% or more in the initial stage of infusibilization and 15% or less in the latter stage. （３）不融化後期に昇温速度を特徴とする特許請求の範
囲第（１）項または第（２）伯記載のピッチ繊維の不融
化方法。(3) A method for infusible pitch fibers according to claim (1) or (2), characterized in that the temperature rise rate is increased in the late stage of infusibility. （４）不融化がピッチ繊維を収容する通気孔を有する容
器を中段あるいは多段に積んでバッチ炉あるいは半連続
炉にて行なわれる特許請求の範囲第（１）項記載のピッ
チ繊維の不融化方法。(4) A method for infusibility of pitch fibers according to claim (1), wherein the infusibility is carried out in a batch furnace or a semi-continuous furnace by stacking containers having ventilation holes for accommodating pitch fibers in middle or multiple stages. . （５）繊維層を通過するガス速度を０．０２〜３．　ｍ
　７秒の範囲で強制通風する特許請求の範囲第（４）項
のピッチ繊維の不融化方法。(5) The gas velocity passing through the fiber layer is set to 0.02 to 3. m
A method for infusible pitch fibers according to claim (4), in which forced ventilation is carried out for a period of 7 seconds.