JPH0635584B2 - Storage method for raw material pitch for carbon fiber - Google Patents

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明はピツチの貯蔵方法に関するものであり、より詳
しくは高特性のピツチ系炭素繊維を製造する際に用いる
粗原料ピツチを貯蔵する方法に関するものである。Description: FIELD OF THE INVENTION The present invention relates to a method for storing pits, and more particularly to a method for storing raw material pits used for producing high-performance pitched carbon fibers. It is a thing.

（従来の技術） 近年炭素繊維はプラスチツクあるいは金属との複合材料
としてその性能を高く評価されており、特にピツチ系の
炭素繊維については種々研究がなされている。(Prior Art) In recent years, the performance of carbon fibers has been highly evaluated as a plastic or a composite material with a metal, and in particular, various studies have been conducted on pitch-based carbon fibers.

ピツチ系炭素繊維の高特性化は、従来紡糸原料として使
用していた等方質ピツチの代りに原料ピツチを加熱処理
して異方性が発達し配向しやすい分子種が形成されたピ
ツチ、すなわちメソフエーズピツチが使用され、主に紡
糸ピツチの性状を調節することにより行われている。Pitch-based carbon fiber is made to have high characteristics by replacing the isotropic pitch used as a spinning raw material in the past with a heat treatment of the raw material pitch and forming a molecular species in which anisotropy is easily developed and oriented, that is, a pitch. Mesophase pitches are used and are mainly done by adjusting the properties of the spinning pitches.

しかしながら、通常のピツチ類は、加熱処理により生成
するメソフエーズを形成するに有用な成分、すなわちβ
−レジン成分の含有量が少なくかつ、低分子から高分子
までの広い分子量分布を有しているため、これら原料ピ
ツチを用い紡糸ピツチを製造する場合、メソフエーズの
形成に関与する部分も少なく、また、熱処理によつて低
分子域と高分子域でのメソフエーズ生成が異なり、均一
なメソフエーズの生成が困難となる欠点があつた。However, ordinary pitches contain a component useful for forming mesophases formed by heat treatment, that is, β.
-Since the content of the resin component is low and it has a wide molecular weight distribution from low molecular weight to high molecular weight, when producing spinning pitches using these raw material pitches, there are few parts involved in the formation of mesophases, and However, the heat treatment causes different mesophase formation in the low molecular weight region and the high molecular weight region, which makes it difficult to generate uniform mesophase.

そこでこれらの欠点を克服する方法として、コールター
ル又はコールタールソフトピツチを芳香族系溶媒又は芳
香族系溶媒と脂肪族溶媒との混合溶媒で処理する方法
（特開昭５４−16047号公報、特開昭５８−１５６０２
７号公報参照）が提案されている。Therefore, as a method of overcoming these drawbacks, a method of treating coal tar or coal tar soft pitch with an aromatic solvent or a mixed solvent of an aromatic solvent and an aliphatic solvent (JP-A-54-16047, JP Kaisho 58-15602
No. 7) is proposed.

また、紡糸工程へ供給される溶融状態の紡糸ピツチは外
気と接触すると、該紡糸ピツチが酸化され、不溶融物状
態となり易いので、溶融状態の紡糸ピツチを移送する際
には、計量ポンプとして用いられる自己潤滑型のポンプ
の回転軸部分を空気と遮蔽する（特開昭５９−１７０１
８５号公報）ことが知られていた。Further, when the melted spinning pitch supplied to the spinning step comes into contact with the outside air, the spinning pitch is easily oxidized and becomes a non-melted state. The rotating shaft portion of the self-lubricating pump used is shielded from air (Japanese Patent Laid-Open No. 59-1701)
No. 85) was known.

（発明が解決しようとする問題点） しかして、本発明者等の知見によれば公知の方法で得ら
れる炭素繊維用粗原料ピツチを６０℃以上の温度で長時
間貯蔵しようとすると通常の不活性雰囲気であつても次
第に経時変化を受けて、該ピツチの一部が重質化、高分
子化あるいはゲル化して該ピツチの物性が変化し、かか
るピツチの物性が変化すると紡糸ピツチの物性自体が変
化して、ひいては、紡糸性が低下するとともに高特性の
ピツチ系炭素繊維を得ることができないという問題点が
見出された。(Problems to be Solved by the Invention) However, according to the findings of the present inventors, when the raw material pitch for carbon fiber obtained by the known method is stored for a long time at a temperature of 60 ° C. or higher, it is not normal Even in an active atmosphere, a part of the pitch undergoes a gradual change with time, and a part of the pitch becomes heavy, polymerized or gelled to change the physical properties of the pitch. When the physical properties of the pitch change, the physical properties of the spinning pitch itself. It was found that there was a problem that the spinnability was lowered, and that the Pitch-based carbon fiber with high characteristics could not be obtained.

（問題点を解決するための手段） 本発明者等は上記の問題点を解決すべく鋭意検討した結
果、粗原料ピツチを加熱処理して得られる紡糸ピツチと
は異なり、一般に比較的安定な物質として考えられてい
た炭素繊維用粗原料ピツチは酸素に対して特段に不安定
であり、貯蔵する雰囲気中に微量の酸素が存在しても経
時的にその組成が変化し易いものであることを見い出
し、かかる性質を有する粗原料ピツチを用いて高特性の
ピツチ系炭素繊維を与える紡糸ピツチを得るためには、
粗原料ピツチを特定濃度以下の酸素を含有する雰囲気下
で保持することが不可欠であることを見い出し本発明に
到達した。(Means for Solving Problems) The inventors of the present invention have conducted diligent studies to solve the above problems, and as a result, unlike a spinning pitch obtained by heating a raw material pitch, a generally stable substance. The raw material pitch for carbon fiber, which was considered to be, is particularly unstable with respect to oxygen, and its composition is likely to change with time even if a trace amount of oxygen is present in the atmosphere for storage. In order to find a spinning pitch that gives a high-performance pitch-based carbon fiber using the raw material pitch having such properties,
It has been found that it is indispensable to keep the raw material pitch under an atmosphere containing oxygen at a specific concentration or less, and the present invention has been completed.

すなわち、本発明の目的は炭素繊維用粗原料ピツチを経
時的に変化させることなく、貯蔵あるいは次工程へ搬送
して紡糸性に優れ、かつ高特性のピツチ系炭素繊維を与
えるような紡糸ピツチを得るための炭素繊維用粗原料ピ
ツチの貯蔵方法を提供するものである。That is, the object of the present invention is to provide a spinning pitch which does not change the raw material pitch for carbon fiber with time and is stored or conveyed to the next step to have excellent spinnability and to give a pitch-based carbon fiber having excellent characteristics. The present invention provides a method for storing a raw material pitch for carbon fiber for obtaining the same.

そしてその目的は、炭素繊維用粗原料ピツチを無溶媒下
溶融状態で、あるいは溶媒と混合して貯蔵する際に、酸
素濃度が１０００ppm以下の不活性気体雰囲気下に保持
することにより容易に達成される。And the object is easily achieved by keeping the raw material pitch for carbon fiber in a molten state without a solvent or in a mixed state with a solvent by keeping it in an inert gas atmosphere with an oxygen concentration of 1000 ppm or less. It

以下、本発明を詳細に説明する。Hereinafter, the present invention will be described in detail.

本発明で紡糸ピツチを得るために粗原料ピツチとして
は、例えば石炭系のコールタール、コールタールピツ
チ、石炭液化物、石油系の重質油、タール、ピツチ等
で、ベンゼン不溶分６０重量％以下、好ましくは、５０
重量％以下、更に好ましくは、５〜４５重量％、キノリ
ン不溶分２０重量％以下、好ましくは１５重量％以下、
更に好ましくは、５重量％以下のものが挙げられる。As the raw material pitch for obtaining the spinning pitch in the present invention, for example, coal-based coal tar, coal tar pitch, coal liquefaction, petroleum heavy oil, tar, pitch, etc., benzene insoluble content of 60% by weight or less , Preferably 50
Wt% or less, more preferably 5 to 45 wt%, quinoline insoluble content 20 wt% or less, preferably 15 wt% or less,
More preferably, it is 5% by weight or less.

この炭素質原料のベンゼン不溶分、キノリン不溶分が上
記範囲を越えると得られる紡糸ピツチの溶融粘度が高く
なり、従つて、高温にて紡糸しなければならなくなる。
その為、紡糸中に紡糸ピツチの熱改質を生じやすくな
り、好ましくない。If the benzene-insoluble content and the quinoline-insoluble content of the carbonaceous raw material exceed the above-mentioned ranges, the melt viscosity of the obtained spinning pitch becomes high, and accordingly, spinning must be performed at a high temperature.
Therefore, thermal modification of the spinning pitch is likely to occur during spinning, which is not preferable.

また、本発明で用いる溶媒としては、次工程で用いる溶
媒すなわち、メソ化処理を行なう前の予備処理の際に用
いる溶媒であれば特に限定されるものではない。具体的
にはナフタリン油、吸収油、クレオソート油、アントラ
セン油、テトラリン、デカリン、テトラヒドロチノリン
等が挙げられる。溶媒は、粗原料ピツチ１重量部あたり
0.5〜２０重量部、好ましくは１〜１０重量部用いられ
る。ピツチの性状、温度、および溶媒の種類により、ピ
ツチはその全量が溶解することもあるし、その一部、例
えば５〜３０wt％程度が不溶物として残りスラリーを形
成していることもある。Further, the solvent used in the present invention is not particularly limited as long as it is a solvent used in the next step, that is, a solvent used in the pretreatment before the meso treatment. Specific examples include naphthalene oil, absorbing oil, creosote oil, anthracene oil, tetralin, decalin, tetrahydrotinoline and the like. Solvent per 1 part by weight of raw material pitch
0.5 to 20 parts by weight, preferably 1 to 10 parts by weight is used. Depending on the nature of the pitch, the temperature, and the type of solvent, the whole quantity of the pitch may dissolve, or a part thereof, for example, about 5 to 30 wt%, may remain as an insoluble matter to form a slurry.

本発明においては、上記粗原料ピツチと上記溶媒とを混
合する際に、酸素濃度が１０００ppm以下、好ましくは
５００ppm以下の不活性気体雰囲気下で保持することが
重要である。またピツチを保持する温度は通常６０℃以
上、好ましくは１００〜３００℃である。また粗原料ピ
ツチを無溶媒下溶融状態で貯蔵する場合は１００℃以
上、好ましくは１５０〜３００℃で貯蔵するのが好まし
い。低温ではピツチの変質は少ないが、粘度が高く貯蔵
運搬に不都合である。In the present invention, when mixing the raw material pitch and the solvent, it is important to maintain the oxygen concentration in an inert gas atmosphere having an oxygen concentration of 1,000 ppm or less, preferably 500 ppm or less. The temperature for holding the pitch is usually 60 ° C or higher, preferably 100 to 300 ° C. When the raw material pitch is stored in a molten state in the absence of a solvent, it is preferably stored at 100 ° C or higher, preferably 150 to 300 ° C. At low temperatures, the pitch is less likely to deteriorate, but it has a high viscosity and is inconvenient for storage and transportation.

かかる特定の酸素濃度以下の不活性雰囲気下で保持する
ことにより粗原料ピツチの経時的な物性変化を極力抑制
することができ高特性ピツチ系炭素繊維を与える紡糸ピ
ツチを安定的に製造することができる。また、粗原料ピ
ツチの物性変化を更に極力抑制するためには酸素濃度以
外に、水分量も同時に考慮することが好ましい。It is possible to stably produce a spinning pitch that can suppress the change in physical properties of the raw material pitch over time by holding it in an inert atmosphere having a specific oxygen concentration or less and that can provide a high-performance pitch-based carbon fiber. it can. In addition to the oxygen concentration, it is preferable to consider the water content at the same time in order to further suppress the change in the physical properties of the raw material pitch.

すなわち、不活性気体中に含有される水分量を５００pp
m以下、好ましくは３００ppm以下とするのが望ましい。That is, the amount of water contained in the inert gas is 500 pp.
It is desirable that the content be m or less, preferably 300 ppm or less.

また不活性気体としては、通常用いられる気体であれば
特に限定されるものではないが、好ましくは窒素，アル
ゴン等が用いられる。また、水素あるいは低級炭化水素
等の非酸性ガスも本発明の不活性ガスに含めるものとす
る。The inert gas is not particularly limited as long as it is a commonly used gas, but nitrogen, argon or the like is preferably used. Further, non-acidic gas such as hydrogen or lower hydrocarbon is also included in the inert gas of the present invention.

なお、不活性ガス中の酸素濃度を上記の範囲内とする方
法としては公知の方法であれば特に限定されるものでは
ないが、具体的には不活性ガスに小量の水素を混入させ
た後、パラジウム触媒層を通過させる方法、あるいは活
性鉄粉層を通過させる方法等が挙げられる。また水分量
を減少させる方法としてはモレキユラーシープもしくは
シリカゲル等の充填層を通過させることにより行なわれ
る。The method for controlling the oxygen concentration in the inert gas within the above range is not particularly limited as long as it is a known method, but specifically, a small amount of hydrogen is mixed in the inert gas. Then, a method of passing through the palladium catalyst layer, a method of passing through the active iron powder layer, or the like can be mentioned. A method of reducing the water content is to pass through a packed bed of molecular sieve or silica gel.

なお、前記の予備処理としては、前記粗原料ピツチを３
５０〜５００℃、常圧〜１０kg／cm²・Ｇで0.5〜２０時
間程度加熱処理して光学的異方性部分を少なくとも３０
％以上、好ましくは、５０％以上、特に好ましくは、７
０％以上含むような熱処理物を得、次いで、この熱処理
物１重量部に対して約0.1〜３重量部の沸点又は初留点
が１５０℃以上の芳香族油と接触させ、その可溶分を得
るものである。芳香族油としては、ナフタリン油、吸収
油、クレオソート油又はアントラセン油が好ましい。In addition, as the preliminary treatment, the raw material pitch was
Heat-treat at 50 to 500 ° C. and atmospheric pressure to 10 kg / cm ² · G for 0.5 to 20 hours for at least 30 parts of the optically anisotropic portion.
% Or more, preferably 50% or more, particularly preferably 7
A heat-treated product containing 0% or more of the heat-treated product is then contacted with an aromatic oil having a boiling point or an initial boiling point of 150 ° C. or higher of about 0.1 to 3 parts by weight with respect to 1 part by weight of the heat-treated product, and the soluble content thereof is obtained. Is what you get. As the aromatic oil, naphthalene oil, absorbing oil, creosote oil or anthracene oil is preferable.

この予備処理の意味については、完全に明らかではない
が、以後の処理では再び適当物質に復原し得ない比較的
高分子量部分を予じめ削除することにあると本発明者等
によつて推測される。なお、かかる意味を充足する手段
として粗原料ピツチあるいは、上記芳香族油可溶分をテ
トラリン、デカリン、テトラヒドロキノリン、水添した
芳香族油の水素供与性溶剤と共に、あるいは、水素供与
性溶剤に容易に転換しうるキノリン、ナフタリン油、ア
ントラセン油等の溶剤と触媒として鉄系化合物、モリブ
デンを含む担持又は非担持触媒を触媒に添加して、水素
ガス加圧下３６０〜５００℃にて水添処理後必要に応じ
過等で固形分を除去し、更に必要に応じて蒸留等によ
つて、溶媒を除いて残渣物を得る方法も考えられる。Although the meaning of this pretreatment is not completely clear, it is assumed by the present inventors that the relatively high molecular weight portion that cannot be restored to an appropriate substance again in the subsequent treatment is to be removed in advance. To be done. As a means for satisfying such a meaning, the raw material pitch or the aromatic oil-soluble component is used together with a hydrogen donating solvent of tetralin, decalin, tetrahydroquinoline, hydrogenated aromatic oil, or a hydrogen donating solvent. After adding a solvent such as quinoline, naphthalene oil, or anthracene oil, which can be converted to the above, and a supported or unsupported catalyst containing an iron-based compound and molybdenum as a catalyst to the catalyst, hydrogenation treatment is performed at 360 to 500 ° C. under hydrogen gas pressure. A method is also conceivable in which the solid content is excessively removed if necessary, and further the solvent is removed by distillation or the like to obtain the residue, if necessary.

次いで、前記の予備処理を行なつた粗原料ピツチを３５
０〜５００℃、常圧〜１０kg／cm²Ｇで２分〜２０時間
程度加熱処理することにより得ることができる。その
際、不活性ガスの吹込みや撹拌を行なつてもよい。Then, the raw material pitch which has been subjected to the above-mentioned pretreatment is
It can be obtained by heat treatment at 0 to 500 ° C. and normal pressure to 10 kg / cm ² G for about 2 minutes to 20 hours. At that time, an inert gas may be blown in or stirred.

本発明においては、光学的異方性相を４０％以上、好ま
しくは、７０〜１００％、特に好ましくは、９０〜１０
０％含み、しかも、キノリン不溶分が４０重量％以下、
好ましくは、３０重量％以下、特に好ましくは、２５重
量％以下の紡糸ピツチを得るように上記加熱処理条件を
選ぶ必要がある。特に、強度分布のバラツキの小さい炭
素繊維を得るための紡糸ピツチを調製するためには、温
度４００〜５００℃、窒素ガスの吹込み量をピツチ１０
ｇあたり0.1／分〜５／分、加熱時間は、温度、窒
素ガスの吹込み量によつて変化があるものの１時間以内
とすればよい。異方性相があまり少ないと紡糸性が低下
するので前記範囲のものが好ましい。また、キノリン不
溶分は前記範囲を越えると溶融温度の増加をもたらし、
紡糸が不利になる。In the present invention, the optically anisotropic phase is 40% or more, preferably 70 to 100%, particularly preferably 90 to 10%.
0% and quinoline insoluble content is 40% by weight or less,
It is necessary to select the above heat treatment conditions so as to obtain a spinning pitch of preferably 30% by weight or less, particularly preferably 25% by weight or less. In particular, in order to prepare a spinning pitch for obtaining a carbon fiber having a small variation in strength distribution, the temperature is 400 to 500 ° C. and the blowing amount of nitrogen gas is 10.
The heating time may be 0.1 hour / minute to 5 minutes / g, and the heating time may be within 1 hour although it varies depending on the temperature and the blowing amount of nitrogen gas. If the amount of the anisotropic phase is too small, the spinnability is reduced, so that the range is preferable. Further, if the quinoline insoluble content exceeds the above range, the melting temperature increases,
Spinning becomes a disadvantage.

尚、本発明でいう熱処理物の光学的異方性相の含量は、
常温下偏光顕微鏡での熱処理物試料中の光学的異方性を
示す部分の面積割合として求めた値である。The content of the optically anisotropic phase in the heat-treated product according to the present invention is
It is a value obtained as an area ratio of a portion showing optical anisotropy in a heat-treated product sample under a polarization microscope at room temperature.

具体的には、例えば、熱処理物試料を数mm角に粉砕した
ものを常法に従つて約２cm直径の樹脂の表面のほぼ全面
に試料片を埋込み、表面を研磨後、表面全体をくまなく
偏光顕微鏡（100倍率）下で観察し、試料の全表面積に
占る光学的異方性相の面積の割合を測定することによつ
て求める。Specifically, for example, a heat-treated sample crushed into a few mm square is embedded with a sample piece on almost the entire surface of a resin having a diameter of about 2 cm according to a conventional method, and after polishing the surface, the entire surface is covered all over. It is obtained by observing under a polarizing microscope (100 magnification) and measuring the ratio of the area of the optically anisotropic phase to the total surface area of the sample.

この様にして得られた紡糸ピツチを公知の方法に従い、
溶融紡糸し、得られた繊維状ピツチを不融化、炭化し、
場合によつては更に黒鉛化する事により、強度が向上
し、かつ強度分布のバラツキが小さいピツチ系炭素繊維
を得る事ができる。According to a known method, the spinning pitch thus obtained is
Melt spinning, infusibilize and carbonize the resulting fibrous pitch,
In some cases, by further graphitizing, it is possible to obtain a Pitch-based carbon fiber having improved strength and a small variation in strength distribution.

（効果） 本発明によれば、粗原料ピツチを無溶媒下溶融状態で、
あるいは溶媒と混合する際に、特定値以下の酸素濃度を
含有する不活性雰囲気下で保持することにより、粗原料
ピツチの経時的な物性変化を抑制できるため、高特性の
ピツチ系炭素繊維を与える紡糸ピツチを安定的に製造で
きるので、本発明は工業的に非常に有用な発明である。(Effect) According to the present invention, the raw material pitch is melted without solvent,
Alternatively, when mixed with a solvent, by holding in an inert atmosphere containing an oxygen concentration of a specific value or less, it is possible to suppress the change in physical properties of the raw material pitch over time, and thus to give a high-performance Pitch-based carbon fiber. The present invention is an industrially very useful invention because a spinning pitch can be stably produced.

以下、本発明を実施例により具体的に説明するが、本発
明の要旨をこえない限り、下記実施例に限定されるもの
ではない。Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist of the present invention.

実施例１ 炭素繊維製造用粗原料ピツチと石油系重質油を重量比と
して１：３の割合で撹拌機付きの貯槽にて１３０℃の温
度で混合して貯蔵した。この混合溶液のトルエン不溶分
は１８．９重量％であつた。次いで１３０℃の温度にて
撹拌下１２時間保存した。Example 1 Raw material pitch for carbon fiber production and heavy petroleum oil were mixed and stored at a temperature of 130 ° C. in a storage tank equipped with a stirrer at a weight ratio of 1: 3. The toluene insoluble content of this mixed solution was 18.9% by weight. Then, the mixture was stored at 130 ° C. for 12 hours with stirring.

なお、この時貯槽の気相部はパラジウム触媒を用いて脱
酸素処理した窒素ガス雰囲気であり、酸素濃度は約３５
０ppmであつた。１２時間後に再度溶液のトルエン不溶
分を測定した所19.0％でほとんど変化はなかつた。この
原料を用いて鉄触媒を用い、４５０℃、水素圧力１５０
kg／cm²Ｇの（溶媒分圧２〜３kg）水素雰囲気下で１時
間反応させ、得られた反応液より、不溶分を0.5μのフ
イルターにて別後、溶媒を蒸留回収することにより水
添ピツチを得た。この水添ピツチを窒素の吹込み管を設
けた反応器に移行させ、撹拌下４３０℃の温度で１２０
分間熱処理することによりメソフエーズピツチを得た。
得られたメソフエーズピツチの光学的異方性割合は１０
０％であつた。At this time, the gas phase of the storage tank was a nitrogen gas atmosphere deoxidized using a palladium catalyst, and the oxygen concentration was about 35.
It was 0 ppm. After 12 hours, when the toluene-insoluble content of the solution was measured again, there was almost no change at 19.0%. Using this raw material and an iron catalyst, 450 ° C., hydrogen pressure 150
After reacting for 1 hour in a hydrogen atmosphere of kg / cm ² G (solvent partial pressure 2-3 kg), insoluble matter is separated from the resulting reaction solution by a 0.5 μ filter, and then the solvent is distilled and recovered to obtain water. I got a pitch. This hydrogenated pitch was transferred to a reactor equipped with a nitrogen blowing tube, and stirred at a temperature of 430 ° C. for 120 hours.
A heat treatment was carried out for 1 minute to obtain a mesophase pitch.
The optical anisotropy ratio of the obtained mesophase pitch is 10
It was 0%.

このメソフエーズピツチを導入口部に６０〜６５＃のメ
タルパウダーを入れたノズル（ノズル長0.2mm、ノズル
径0.1mm）を用いて３４０℃の温度で紡糸し単糸径７μ
までのピツチ繊維が安定して得られた。This mesophase pitch was spun at a temperature of 340 ° C. using a nozzle (nozzle length 0.2 mm, nozzle diameter 0.1 mm) containing 60 to 65 # metal powder in the inlet port and a single yarn diameter of 7 μm.
Pitch fibers up to were obtained stably.

次にこの繊維の空気雰囲気下３１０℃の温度にて不融化
し、更にアルゴン雰囲気下１４００℃で焼成することに
より、糸径９μの焼成糸で引張強度３１２kg／mm²、引
張弾性率２４．６Ｔ／mm²の炭素繊維を得た。Next, this fiber was made infusible at a temperature of 310 ° C. in an air atmosphere, and further fired at 1400 ° C. in an argon atmosphere to give a fired yarn having a yarn diameter of 9 μ, a tensile strength of 312 kg / mm ² , and a tensile elastic modulus of 24.6 T. A carbon fiber of / mm ² was obtained.

比較例１ 実施例１と同一の操作を貯槽の雰囲気が脱酸素処理をし
ない窒素ガス（O₂含有量２５００ppm）であること以外
は全く同一の方法で実施した所、１２時間後のサンプル
のトルエン不溶分は22.2％であつた。この原料から溶媒
を留去して水添ピツチを得、更に４３０℃で１２０分間
熱処理することにより得られたメソフエーズピツチは、
粘度が異常に高く、紡糸に供することが出来なかつた。Comparative Example 1 The same operation as in Example 1 was carried out by the same method except that the atmosphere of the storage tank was nitrogen gas (O ₂ content 2500 ppm) which was not subjected to deoxidation treatment. Toluene of a sample after 12 hours The insoluble content was 22.2%. The mesophase pitch obtained by distilling the solvent from this raw material to obtain a hydrogenated pitch and further heat-treating at 430 ° C. for 120 minutes is:
The viscosity was abnormally high and it could not be used for spinning.

比較例２ 比較例１において４３０℃で８５分間熱処理することに
より実施例１と同一の粘度を示すメソフエーズピツチが
得られた。但し、このメソフエーズピツチの異方性は約
８５％であつた。これを実施例１と同一のノズルを用い
て同一条件で紡糸した所単糸径９μまでのピツチ繊維が
得られた。Comparative Example 2 A mesophase pitch having the same viscosity as that of Example 1 was obtained by heat-treating at 430 ° C. for 85 minutes in Comparative Example 1. However, the anisotropy of this mesophase pitch was about 85%. When this was spun using the same nozzles as in Example 1 under the same conditions, pitch fibers with a single yarn diameter of up to 9μ were obtained.

このピツチ繊維を実施例１と同様に不融化、炭化するこ
とにより、糸径９μの焼成糸を得たが、引張強度２０６
kg／mm²、引張弾性率１７Ｔ／mm²であつた。The pitch fiber was infusibilized and carbonized in the same manner as in Example 1 to obtain a fired yarn having a yarn diameter of 9μ, but the tensile strength was 206.
kg / mm ^2, Atsuta tensile modulus 17T / mm ^2.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】炭素繊維用粗原料ピツチを無溶媒下溶融状
態で、あるいは溶媒と混合して貯蔵する際に、酸素濃度
が１０００ppm以下の不活性気体雰囲気下に保持するこ
とを特徴とする炭素繊維用粗原料ピツチの貯蔵方法。1. A carbon characterized in that when a raw material pitch for carbon fiber is stored in a molten state without a solvent or mixed with a solvent and stored, it is kept in an inert gas atmosphere having an oxygen concentration of 1000 ppm or less. Storage method for raw material pitch for fiber. 【請求項２】不活性気体中の酸素濃度が５００ppm以下
であることを特徴とする特許請求の範囲第１項記載の方
法。2. The method according to claim 1, wherein the oxygen concentration in the inert gas is 500 ppm or less. 【請求項３】不活性気体中に含有される水分量が５００
ppm以下であることを特徴とする特許請求の範囲第１項
記載の方法。3. The amount of water contained in the inert gas is 500.
The method according to claim 1, wherein the content is ppm or less. 【請求項４】不活性気体が窒素であることを特徴とする
特許請求の範囲第１項記載の方法。4. The method according to claim 1, wherein the inert gas is nitrogen.