JPH0813254A - Hollow carbon yarn by fluidized vapor-phase growth method - Google Patents

Abstract

PURPOSE:To obtain a material useful as a reinforcing material for composite materials, having raised denseness of carbon fiber and improved mechanical strength by forming hollow carbon fibers by a fluidized vapor-phase growth method. CONSTITUTION:In a fluidized vapor-phase growth method, a ferrocene of an organic transition metal compound is stored in a carburetor 42 and benzene as a carbon compound is stored in a carburetor 46. A reaction tube 50 is heated by a heater 52 while sending a nitrogen gas from a gas introduction pipe 49 to the reaction tube. When the reaction tube reaches a fixed temperature, a hydrogen gas is introduced from the gas introduction pipe 49 into the reaction tube to replaces the nitrogen gas. Then, hydrogen sulfide gas is sent from the carrier gas introduction pipes 40 and 44 to the carburetors 42 and 46 and the ferrocene and benzene and the hydrogen gas containing hydrogen sulfide as a carrier gas are introduced to the reaction tube 50 to form carbon fibers in a fluidized vapor phase. The carbon fibers are collected by a fiber collecting device 54 composed of a metal fiber filter to give the objective hollow carbon fibers comprising >=90% of the formed carbon fibers containing ultrafine metal particles at the tips of the fibers and having 30-60Angstrom hollow inner diameters.

Description

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

【０００１】[0001]

【産業上の利用分野】この発明は、中空炭素繊維、殊に
一群の流動気相成長炭素繊維の９０％以上が６０Å以下
の中空内径を有する中空炭素繊維に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow carbon fiber, and more particularly to a hollow carbon fiber in which 90% or more of a group of fluid vapor grown carbon fibers have a hollow inner diameter of 60Å or less.

【０００２】[0002]

【従来の技術】炭素繊維は、軽量且つ高強度という材料
特性によって、航空宇宙産業、スポーツ・レジャー産業
等にその利用が急ピッチに拡大されている。2. Description of the Related Art Carbon fibers have been rapidly and rapidly used in the aerospace industry, sports / leisure industry and the like due to their light weight and high strength.

【０００３】炭素繊維は、一般にＰＡＮ（ポリアクリロ
ニトリル）の紡糸、耐炎化、炭素化処理またはピッチの
溶融紡糸、不融化、炭化焼成等によって製造されてい
る。一方、気相成長法による炭素繊維は、不連続繊維で
あるが、結晶性良好な易黒鉛化性炭素繊維であり、２８
００℃以上の熱処理によって、従来の炭素繊維では達成
できない極めて機械的特性に優れた素材になることで注
目を集めている。Carbon fibers are generally produced by PAN (polyacrylonitrile) spinning, flameproofing, carbonization treatment or pitch melt spinning, infusibilization, carbonization firing and the like. On the other hand, the carbon fiber obtained by the vapor growth method is a discontinuous fiber, but is a graphitizable carbon fiber having good crystallinity.
Attention has been paid to the fact that heat treatment at a temperature of 00 ° C or higher makes the material extremely excellent in mechanical properties, which cannot be achieved by conventional carbon fibers.

【０００４】[0004]

【発明が解決しようとする課題】従来、気相法による炭
素繊維は、アルミナ、黒鉛等の基板表面に１００Å〜３
００Åの金属超微粒子触媒を担持させて、約１０００℃
の加熱帯域で水素還元した後、気相成長を行うのが一般
であった、しかしながら、超微粒子は凝集二次粒子を形
成し、その分散も容易ではない。また、超微粒子の二次
粒子は、数百度の低温で焼結し、大粒径になり易い。従
って、現実に製造され、入手可能な最も微細な平均粒径
１００Åの超微粒子を使っても、二次粒子の形成とその
焼結によって実際には、１００Åとして機能できる触媒
超微粒子は、ほとんど存在しないことがわかっている。Conventionally, carbon fibers produced by the vapor phase method have 100Å to 3 on the surface of a substrate such as alumina or graphite.
Approximately 1000 ° C, supporting a metal particle catalyst of 00Å
In general, vapor phase growth was performed after hydrogen reduction in the heating zone of 1. However, ultrafine particles form aggregated secondary particles, and their dispersion is not easy. Secondary particles of ultrafine particles are sintered at a low temperature of several hundred degrees and tend to have a large particle size. Therefore, even if the finest ultrafine particles with an average particle size of 100Å that are actually produced and available are used, there are almost no catalyst ultrafine particles that can actually function as 100Å due to the formation of secondary particles and the sintering thereof. I know I won't.

【０００５】気相法により炭素繊維は、中心に中空を有
しているが、その中空径は触媒超微粒子に強く依存して
おり、粒子径が大きくなると中空径も大きくなる。粒径
１００Å以上の触媒を使った場合、その中空径はわずか
に６０Å以下のものが存在するが、二次粒子の形成によ
る触媒の大粒径化によって中空径のほとんどは１００Å
以上になる。According to the vapor phase method, carbon fibers have a hollow at the center, but the hollow diameter strongly depends on the ultrafine catalyst particles, and the larger the particle diameter, the larger the hollow diameter. When a catalyst with a particle size of 100 Å or more is used, the hollow diameter is only 60 Å or less, but most of the hollow diameter is 100 Å due to the large particle size of the catalyst due to the formation of secondary particles.
That's all.

【０００６】中空径は、触媒粒子の大きさと正の相関を
有するものであり、従来のような遷移金属の超微粒子を
基材に散布して後水素還元し、炭素繊維を気相生成する
方法や、遷移金属化合物を溶剤に溶かし、それを基材に
塗布し、同様の手順で炭素繊維を気相生成する方法にお
いては、触媒粒子径を１００Å以下にすることは難し
い。また、中空径についても、触媒粒子が大きくなるた
めに大部分は１００Å以上であり、中には１０００Å程
度のものも存在し、機械的特性に悪影響を与える。The hollow diameter has a positive correlation with the size of the catalyst particles, and the conventional method is to sprinkle ultrafine particles of a transition metal on a substrate and then reduce with hydrogen to produce carbon fibers in a vapor phase. Alternatively, in a method in which a transition metal compound is dissolved in a solvent, which is applied to a base material, and carbon fibers are produced in the vapor phase by the same procedure, it is difficult to set the catalyst particle diameter to 100 Å or less. Also, regarding the hollow diameter, most of them are 100 liters or more due to the large size of the catalyst particles, and some have about 1000 liters, which adversely affects the mechanical properties.

【０００７】出願人は、従来の基板に鉄やニッケルなど
の超微粒子触媒を形成させる手法に代えて、有機遷移金
属化合物のガスを使用して電気炉空間で浮遊する超微粒
子触媒を形成せしめ、それにより浮遊状態で炭素繊維を
成長させる製造方法を完成し、特願昭５８−１６２６０
６号として出願した（以下この方法で製造した炭素繊維
を流動気相成長法による炭素繊維という）。The applicant has replaced the conventional method of forming an ultrafine particle catalyst such as iron or nickel on a substrate by using a gas of an organic transition metal compound to form an ultrafine particle catalyst floating in an electric furnace space. As a result, a manufacturing method for growing carbon fibers in a floating state was completed.
Application was filed as No. 6 (hereinafter, the carbon fiber produced by this method is referred to as a carbon fiber produced by a fluidized vapor phase growth method).

【０００８】更に、出願人はこの流動気相成長法による
炭素繊維につき、その複合材料としての機械的特性、高
分解能透過型電子顕微鏡観察の結果から、流動気相成長
法による炭素繊維の製造において触媒粒径のコントロー
ルによってその大部分の中空径を６０Å以下にすること
が可能であり、またその中空径が小さいほど炭素繊維の
成長速度が速いばかりでなく、優れた複合材料用素材と
なり得ることを突き止めた。[0008] Further, the applicant has confirmed that the carbon fiber produced by the fluidized vapor phase epitaxy method can be used in the production of the carbon fiber produced by the fluidized vapor phase epitaxy method based on the mechanical properties of the composite material and the result of observation with a high resolution transmission electron microscope. By controlling the catalyst particle size, it is possible to make most of the hollow diameters below 60Å. Also, the smaller the hollow diameter, the faster the growth rate of carbon fibers, and the better the material for composite materials. I found out.

【０００９】従って、本発明の目的は、従来の炭素繊維
より機械的特性に著しく優れ複合材料用素材として適し
た中空炭素繊維を提供することにある。Therefore, an object of the present invention is to provide a hollow carbon fiber which is excellent in mechanical properties as compared with conventional carbon fibers and which is suitable as a raw material for composite materials.

【００１０】また、別の目的は、微細触媒を生成し、そ
れによって炭素繊維の気相生成を行うことによって、炭
素繊維の成長速度を増し、生産性をあげることである。Another object is to increase the growth rate of carbon fibers and increase the productivity by producing a fine catalyst and thereby producing the carbon fibers in the vapor phase.

【００１１】[0011]

【課題を解決するための手段】先の目的を達成するた
め、この発明に係る中空炭素繊維は、一群の流動気相成
長炭素繊維において、その９０％以上が３０〜６０Åの
中空内径を有することを特徴とする。In order to achieve the above object, the hollow carbon fiber according to the present invention is such that 90% or more of the hollow carbon fibers in the group of fluidized vapor grown carbon fibers have a hollow inner diameter of 30 to 60Å. Is characterized by.

【００１２】この発明に係る一群の流動気相成長炭素繊
維の９０％以上が３０〜６０Åの中空内径を有する中空
炭素繊維は、濃度調整された有機遷移金属化合物のガス
と、キャリアガスと、必要に応じて炭素化合物のガスと
の混合ガスを加熱分解することにより連続的に製造され
る。Hollow carbon fibers in which 90% or more of the group of fluidized vapor phase growth carbon fibers according to the present invention have a hollow inner diameter of 30 to 60 Å, a concentration-adjusted gas of an organic transition metal compound and a carrier gas are required. Depending on the above, it is continuously produced by thermally decomposing a mixed gas with a gas of a carbon compound.

【００１３】また、この中空炭素繊維は、流動気相成長
法において有機遷移金属化合物の濃度を全混合ガスに対
して０．０１％〜４０％に調整する。反応温度との関係
においては、温度が高いほど低濃度にすることが好まし
い。Further, in the hollow carbon fiber, the concentration of the organic transition metal compound is adjusted to 0.01% to 40% with respect to the total mixed gas in the fluidized vapor phase growth method. In relation to the reaction temperature, it is preferable that the higher the temperature, the lower the concentration.

【００１４】これは金属原子の濃度が高くなると、その
凝集速度が速くなり、大きな粒子となり易いためと考え
られる。すなわち温度が高いと有機遷移金属化合物の分
解速度が大きくなり、気相中の金属原子の濃度が高くな
り、また有機遷移金属化合物の濃度が高いと同じく金属
原子の濃度が高くなる。それらの具体的な濃度や温度の
数値は、昇温速度や炭化水素濃度、その温度での滞在時
間などにより異なる。炭化水素の濃度が高いと粒子が大
きくなる前に繊維を生成するので、中空径の小さい繊維
の比率が大きくなると考えられるし、また温度が同じで
も、昇温速度が速かったり、炭化水素と接触するまでの
時間が長いと粒子が大きくなって、中空径も大きくなる
と考えられる。It is considered that the higher the concentration of metal atoms, the faster the agglomeration rate and the larger the particles tend to be. That is, when the temperature is high, the decomposition rate of the organic transition metal compound increases, the concentration of metal atoms in the gas phase increases, and when the concentration of the organic transition metal compound increases, the concentration of metal atoms also increases. The specific numerical values of the concentration and temperature differ depending on the rate of temperature rise, the hydrocarbon concentration, the residence time at that temperature, and the like. When the concentration of hydrocarbons is high, fibers are formed before the particles become large, so it is considered that the ratio of fibers with small hollow diameters becomes large, and even if the temperature is the same, the rate of temperature rise is high and there is contact with hydrocarbons. It is considered that if the time required for the treatment is long, the particles become large and the hollow diameter also becomes large.

【００１５】従って本発明の好適な態様によれば、一群
の流動気相成長炭素繊維の９０％以上が３０〜６０Åの
中空内径を有する中空炭素繊維を流動気相成長法により
製造するに際し、濃度調整された有機遷移金属化合物の
ガスと、キャリヤガスと、必要に応じて用いる炭素化合
物のガスとの混合ガスを高熱反応させることにより生成
させることからなり、反応温度が高いほど有機遷移金属
化合物の濃度を低濃度にすることを特徴とする流動気相
成長法による中空炭素繊維の製造方法が提供される。Therefore, according to a preferred embodiment of the present invention, 90% or more of a group of fluidized vapor grown carbon fibers has a hollow inner diameter of 30 to 60 Å, which is produced by the fluidized vapor deposition method. The gas of the adjusted organic transition metal compound, a carrier gas, and a gas of a carbon compound to be used as required are produced by high-temperature reaction, and the higher the reaction temperature, the higher the reaction temperature of the organic transition metal compound. Provided is a method for producing hollow carbon fibers by a fluidized vapor phase growth method, which is characterized in that the concentration is low.

【００１６】更に、本発明の他の好適な態様によれば、
一群の流動気相成長炭素繊維の９０％以上が３０〜６０
Åの中空内径を有する中空炭素繊維を流動気相成長法に
より製造するに際し、濃度調整された有機遷移金属化合
物のガスと、キャリヤガスと、必要に応じて用いる炭素
化合物の混合ガスとを高温反応帯域に導入し、有機遷移
金属化合物の熱分解によって生成した触媒として機能し
得る還元及び分散の必要のない発生期の遷移金属の流動
状態の微粒子を触媒とする気相成長によって生成させる
ことからなり、反応温度が高いほど有機遷移金属化合物
の濃度を低濃度にすることを特徴とする流動気相成長法
による中空炭素繊維の製造方法が提供される。Further, according to another preferred aspect of the present invention,
90-60% or more of a group of fluid vapor grown carbon fibers is 30 to 60
When manufacturing hollow carbon fibers with a hollow inner diameter of Å by fluidized vapor phase epitaxy, high-temperature reaction of the concentration-adjusted gas of the organic transition metal compound, the carrier gas, and the mixed gas of carbon compounds used as necessary It is introduced into the zone and functions as a catalyst produced by the thermal decomposition of an organic transition metal compound, and is produced by vapor phase growth using a fluidized state fine particle of a nascent transition metal that does not require reduction and dispersion. A method for producing hollow carbon fibers by a fluidized vapor phase epitaxy method, which comprises lowering the concentration of an organic transition metal compound as the reaction temperature increases.

【００１７】すなわち、より具体的にはベンゼン、メタ
ン等の炭化水素化合物のガスとフェロセン、鉄カルボニ
ル等の有機遷移金属化合物のガスとキャリヤガスとの混
合ガスを６００℃乃至１３００℃の温度で加熱して中空
炭素繊維を生成する。That is, more specifically, a mixed gas of a hydrocarbon compound gas such as benzene and methane, an organic transition metal compound gas such as ferrocene and iron carbonyl, and a carrier gas is heated at a temperature of 600 ° C to 1300 ° C. To produce hollow carbon fibers.

【００１８】本発明における炭素供給源としての炭素化
合物とは、有機鎖式化合物または有機環式化合物からな
る有機化合物全般が対象となるが、特に高い収率を得る
には脂肪族炭化水素、芳香族炭化水素である。しかし、
炭化水素化合物以外に窒素、酸素、硫黄、弗素、塩素、
臭素、沃素、燐、砒素等の内の一種類以上の元素を含む
ものも使用できる。特に炭素と水素と硫黄との組合せか
らなる場合には収率面で好適である。具体的な個々の化
合物の例を挙げると、メタン、エタン等のアルカン化合
物、エチレン、ブタジエン等のアルケン化合物、アセチ
レン等のアルキン化合物、ベンゼン、トルエン、スチレ
ン等のアリール炭化水素化合物、インデン、ナフタリ
ン、フェナントレン等の縮合環を有する芳香族炭化水
素、シクロプロパン、シクロヘキサン等のシクロパラフ
ィン化合物、シクロペンテン、シクロヘキサン等のシク
ロオレフィン化合物、ステロイド等の縮合環を有する脂
環式炭化水素化合物、メチルチオール、メチルエチルス
ルフイド、ジメチルチオケトン等の含硫脂肪族化合物、
フェニルチオール、ジフェニルスルフィド等の含硫芳香
族化合物、ベンゾチオフエン、チオフエン等の含硫複素
環式化合物等である。また、以上の化合物の２種以上を
混合した混合物を使用することも可能である。The carbon compound as a carbon source in the present invention is a general organic compound consisting of an organic chain compound or an organic cyclic compound, but in order to obtain a particularly high yield, an aliphatic hydrocarbon or an aromatic compound is used. It is a group hydrocarbon. But,
In addition to hydrocarbon compounds, nitrogen, oxygen, sulfur, fluorine, chlorine,
It is also possible to use a material containing one or more kinds of elements such as bromine, iodine, phosphorus and arsenic. In particular, the case of a combination of carbon, hydrogen and sulfur is preferred in terms of yield. Specific examples of individual compounds include methane, alkane compounds such as ethane, ethylene, alkene compounds such as butadiene, alkyne compounds such as acetylene, benzene, toluene, aryl hydrocarbon compounds such as styrene, indene, naphthalene, Aromatic hydrocarbons having condensed rings such as phenanthrene, cycloparaffin compounds such as cyclopropane and cyclohexane, cycloolefin compounds such as cyclopentene and cyclohexane, alicyclic hydrocarbon compounds having condensed rings such as steroids, methylthiol and methylethyl Sulfide, sulfur-containing aliphatic compounds such as dimethyl thioketone,
Examples thereof include sulfur-containing aromatic compounds such as phenylthiol and diphenyl sulfide, and sulfur-containing heterocyclic compounds such as benzothiophene and thiophene. It is also possible to use a mixture of two or more of the above compounds.

【００１９】キャリヤガスとしては、周期律表Ｏ族のア
ルゴン、ヘリウム等の希ガスおよび水素、窒素またはこ
れらの混合ガスの中から選択されるガスを主体とし、水
素ガスが最も好ましい。主体とするという意味は、上記
以外に他のガスを含むことが許されることを意味し、そ
の割合はキャリヤガス成分中２０％以内である。この種
の少量成分ガスとしては、硫化水素、二硫化炭素、酸
素、オゾンが好ましい。水素ガス以外のガスをキャリヤ
ガスとして使用する場合、一般に炭素化合物の熱分解が
促進されすぎ、かえって炭素繊維の生成を阻害する要因
になるため、炭素化合物の濃度を大幅に低下させる必要
性が出てくる。As the carrier gas, a gas selected from rare gases such as argon and helium of the periodic table group O and hydrogen, nitrogen or a mixed gas thereof is mainly used, and hydrogen gas is most preferable. The term "mainly composed" means that other gas than the above is allowed to be contained, and the ratio thereof is within 20% in the carrier gas component. Hydrogen sulfide, carbon disulfide, oxygen and ozone are preferred as this kind of small component gas. When a gas other than hydrogen gas is used as the carrier gas, the thermal decomposition of carbon compounds is generally too accelerated, which is a factor that hinders the production of carbon fibers.Therefore, it is necessary to significantly reduce the concentration of carbon compounds. Come on.

【００２０】本発明における有機遷移金属化合物とは、
遷移金属を含む有機化合物全般を対象としている。具体
的にはアルキル基と金属が結合したアルキル金属、アリ
ル基と金属が結合したアリル錯体、炭素間２重結合や３
重結合等と金属とが結合した化合物に代表されるπ結合
が関与する錯体とキレート型化合物およびカルボニル化
合物等に代表される有機遷移金属化合物である。The organic transition metal compound in the present invention is
It covers all organic compounds containing transition metals. Specifically, an alkyl metal in which an alkyl group and a metal are bonded, an allyl complex in which an allyl group and a metal are bonded, a carbon-carbon double bond or 3
A complex involving a π bond represented by a compound in which a heavy bond or the like is bound to a metal and an organic transition metal compound represented by a chelate type compound or a carbonyl compound.

【００２１】また、ここで遷移金属としては、スカンジ
ウム、チタン、バナジウム、クロム、マンガン、鉄、コ
バルト、ニッケル、イットリウム、ジルコニウム、ニオ
ブ、モリブデン、ルテニウム、ロジウム、パラジウム、
タンタル、タングステン、レニウム、イリジウムまたは
白金を指すものであるが、これらの内特に周期律表ＶＩ
ＩＩ族に属するもの、その内で特に鉄、ニッケル、コバ
ルトが好適であって、鉄が最も好適である。The transition metals used here are scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium,
It refers to tantalum, tungsten, rhenium, iridium, or platinum, and among these, especially the periodic table VI
Those belonging to Group II, of which iron, nickel, and cobalt are particularly preferable, and iron is most preferable.

【００２２】有機遷移金属化合物の一部具体的例を挙げ
ると、アルキル金属として（Ｃ_４Ｈ_９）_４Ｔｉ，Some specific examples of the organic transition metal compound include (C ₄ H ₉ ) ₄ Ti, as an alkyl metal.

【００２３】[0023]

【化１】 Embedded image

【００２４】（Ｃ_２Ｈ_５）_２ＦｅＢｒ，（Ｃ_２Ｈ_５）Ｆ
ｅＢｒ_２； アリル錯体として（Ｃ_６Ｈ_５）_３ＰｔＩ；π結合が関与
する錯体として（Ｃ_５Ｈ_５）_２Ｆｅ，（Ｃ_６Ｈ_６）_２Ｍ
ｏ，（Ｃ_９Ｈ_７）_２Ｆｅ，〔Ｃ_５Ｈ_５Ｆｅ（ＣＯ）_２〕
_２，〔Ｃ_５Ｈ_５Ｆｅ（ＣＯ）_２〕Ｃｌ，〔Ｃ_５Ｈ_５Ｆｅ
（ＣＯ）_２〕ＣＮ，(C ₂ H ₅ ) ₂ FeBr, (C ₂ H ₅ ) F
eBr ₂ ; (C ₆ H ₅ ) ₃ PtI as an allyl complex; (C ₅ H ₅ ) ₂ Fe, (C ₆ H ₆ ) ₂ M as a complex involving a π bond
_{o, (C 9 H 7)} 2 Fe, _{[C 5 H 5 Fe (CO)} 2 ]
₂ , [C ₅ H ₅ Fe (CO) ₂ ] Cl, [C ₅ H ₅ Fe
(CO) ₂ ] CN,

【００２５】[0025]

【化２】 Embedded image

【００２６】[0026]

【化３】 Embedded image

【００２７】キレート型化合物としてAs a chelate-type compound

【００２８】[0028]

【化４】 [Chemical 4]

【００２９】カルボニル化合物として Ｆｅ（ＣＯ）_５，Ｆｅ_２（ＣＯ）_９，Ｎｉ（ＣＯ）_４，
Ｃｒ（ＣＯ）_６，Ｗ（ＣＯ）_６等である。また、有機遷
移金属化合物の混合物の使用も可能である。As carbonyl compounds, Fe (CO) ₅ , Fe ₂ (CO) ₉ , Ni (CO) ₄ ,
Cr (CO) ₆ , W (CO) _{6 and the} like. It is also possible to use mixtures of organic transition metal compounds.

【００３０】本発明における製造方法を具体的に説明す
ると、有機遷移金属化合物のガスとキャリヤガスと必要
に応じて炭素化合物のガスとの混合ガスを、好ましくは
６００℃〜１３００℃より好ましくは８００℃〜１２５
０℃、更に好適には１０００℃〜１２００℃に加熱す
る。炭素化合物、有機遷移金属化合物がガス状ならばそ
のまま、液体または固体の場合は加熱蒸発または昇華さ
せて得られるガスを使用し、炭素化合物のガスおよび有
機遷移金属化合物のガスの全混合ガスに占める割合は、
好ましくは各々炭素化合物のガス０〜４０％、有機遷移
金属化合物のガス０．０１％〜４０％、更に好ましくは
各々炭素化合物のガス５．０％〜２０％、有機遷移金属
化合物のガス０．０５％〜５．０％である。ここで、炭
素化合物の濃度が０でも良いのは有機遷移金属化合物中
に十分な炭素を含有している場合は、必ずしも炭素化合
物のガスを必要としないという意味である。混合ガスの
加熱方法としては電気炉による方法が簡便であるが、そ
の他、レーザ加熱、高周波加熱、赤外線ヒーター加熱、
プラズマ加熱等も可能である。The production method of the present invention will be described in detail. A mixed gas of a gas of an organic transition metal compound, a carrier gas and, if necessary, a gas of a carbon compound is preferably 600 ° C. to 1300 ° C., more preferably 800 ° C. ℃ ~ 125
It is heated to 0 ° C, more preferably 1000 ° C to 1200 ° C. If the carbon compound or organic transition metal compound is in a gaseous state, it is used as it is, and if it is a liquid or a solid, the gas obtained by heating and evaporation or sublimation is used, and it occupies the total mixed gas of the carbon compound gas and the organic transition metal compound gas. The percentage is
Preferably, the carbon compound gas is 0 to 40%, the organic transition metal compound gas is 0.01% to 40%, and more preferably the carbon compound gas is 5.0% to 20%, the organic transition metal compound gas is 0. It is from 05% to 5.0%. Here, the concentration of the carbon compound may be 0, which means that the gas of the carbon compound is not always required when the organic transition metal compound contains sufficient carbon. As a method for heating the mixed gas, a method using an electric furnace is simple, but in addition, laser heating, high frequency heating, infrared heater heating,
Plasma heating or the like is also possible.

【００３１】本発明は、炭素供給源としての炭素化合物
のガスと、従来気相成長炭素繊維の生成に不可欠な触媒
となっている金属からなる有機金属化合物のガスとを反
応炉内で同時に熱分解させる方法で実施できるが、この
方法により炭素繊維が得られたという事実から反応管内
部では２段階の反応が起っていると考える。まず、反応
管の内部温度が比較的低い部分で有機金属化合物のみが
熱分解し、２０〜６０Å程度の金属超微粒子が生成し
（第１段階）、次に炭素繊維が流動状態で気相生成する
（第２段階）。According to the present invention, a gas of a carbon compound as a carbon supply source and a gas of an organometallic compound made of a metal which has conventionally been an indispensable catalyst for the production of vapor-grown carbon fibers are simultaneously heated in a reaction furnace. Although it can be carried out by a method of decomposing, it is considered that a two-step reaction occurs inside the reaction tube due to the fact that carbon fibers were obtained by this method. First, only the organometallic compound is thermally decomposed in the portion where the internal temperature of the reaction tube is relatively low, and ultrafine metal particles of about 20 to 60 Å are generated (first step), and then the carbon fiber is generated in the gas phase in a fluid state. Do (second stage).

【００３２】[0032]

【作用】流動気相成長法においては、有機遷移金属化合
物の熱分解によって有機遷移金属化合物の濃度に依存し
た大きさの触媒の気相生成が起り、気相中によく分散さ
れた発生期の金属超微粒子触媒によって炭素繊維が浮遊
状態で気相生成される。すなわち、高い温度域で発生し
た金属超微粒子は、凝集二次粒子を形成しにくいため、
発生期の小さい触媒径に依存した形で炭素繊維生成が行
われ、それ故中空内径の小さい炭素繊維が得られる。ま
た、触媒粒子径が小さいほど炭素繊維の成長速度が速い
ため生産性の増加につながって炭素繊維が高収率で得ら
れる。[Function] In the fluidized vapor phase growth method, the thermal decomposition of the organic transition metal compound causes vapor phase formation of a catalyst having a size depending on the concentration of the organic transition metal compound. The carbon fibers are generated in a gas phase in a suspended state by the ultrafine metal particle catalyst. That is, the ultrafine metal particles generated in the high temperature range are difficult to form aggregated secondary particles,
Carbon fiber production is carried out in a manner depending on the nascent catalyst diameter, and therefore a carbon fiber having a small hollow inner diameter is obtained. In addition, the smaller the catalyst particle size, the faster the growth rate of carbon fibers, which leads to an increase in productivity and the high yield of carbon fibers.

【００３３】[0033]

【実施例】【Example】

実施例１ 次に、この発明に係る流動気相成長法による中空炭素繊
維につきその製造及び観察の実施例を添付図面を参照し
ながら以下説明する。Example 1 Next, an example of manufacturing and observing a hollow carbon fiber by a fluidized vapor phase growth method according to the present invention will be described below with reference to the accompanying drawings.

【００３４】図１は実施例１に使用した装置の概略系統
図である。実施例１においては、有機金属化合物として
（Ｃ_５Ｈ_５）_２Ｆｅ（フェロセン）を、炭素化合物とし
てＣ_６Ｈ_６（ベンゼン）を、キャリヤガスとして３％の
硫化水素を含むＨ_２ガスを用いた。反応管はアルミナ製
で内径５０ｍｍ、長さ１５００ｍｍであり、加熱装置の
加熱部の有効長は９００ｍｍ、均熱帯域は約３００ｍｍ
である。まず、気化器４２及び４６には、それぞれ（Ｃ
_５Ｈ_５）_２Ｆｅ及びＣ_６Ｈ_６を貯えた。ガス導入管４９
から５００ｍｌ／ｍｉｎの流量で反応管内にＮ_２ガスを
送りながら、加熱器５２を昇温した。温度が一定に達し
てから、ガス導入管４９よりＨ_２ガスを１０００ｍｌ／
ｍｉｎの流量で反応管に送りガス置換を行った。３０分
のガス置換後、キャリヤガス導入管４０及び４４にＨ_２
ガスを導入しガス導入管４９よりＨ_２Ｓガスを導入し
た。反応管に入る直前におけるガスの組成は、Ｈ_２：Ｈ
_２Ｓ：（Ｃ_５Ｈ_５）_２Ｆｅ：Ｃ_６Ｈ_６＝８５．３：２．
６：０．３：１１．８で、総流量は１１６８ｍｌ／ｍｉ
ｎ（常温、常圧換算）であった。均熱部の温度は１１０
０℃であり、生成した炭素繊維は繊維捕集装置５４とし
て金属繊維フィルターを使用し、そこで捕集した。反応
管内及びステンレス繊維フィルターで捕集された炭素繊
維の高分解能透過型電子顕微鏡観察を行ったところ、直
径０．１μｍ、長さ約４０μｍ、中空径約４０Åの微細
炭素繊維が得られた。またこの時の収率は５８％であっ
た。繊維２０本につき中空径を計測したところ、全て６
０Å以下であり値を統計的に処理すると、３９ű５Å
（９５％信頼限界）であった。FIG. 1 is a schematic system diagram of the apparatus used in Example 1. In Example 1, (C ₅ H ₅ ) ₂ Fe (ferrocene) was used as the organometallic compound, C ₆ H ₆ (benzene) was used as the carbon compound, and H ₂ gas containing 3% hydrogen sulfide was used as the carrier gas. I was there. The reaction tube is made of alumina and has an inner diameter of 50 mm and a length of 1,500 mm, the effective length of the heating part of the heating device is 900 mm, and the soaking zone is about 300 mm.
Is. First, the vaporizers 42 and 46 have (C
₅ H ₅ ) ₂ Fe and C ₆ H ₆ were stored. Gas introduction pipe 49
The temperature of the heater 52 was raised while feeding N ₂ gas into the reaction tube at a flow rate of 500 ml / min. After the temperature reached a certain level, 1000 mL / H ₂ gas was supplied through the gas inlet pipe 49.
It was sent to the reaction tube at a flow rate of min to perform gas replacement. After gas replacement for 30 minutes, H ₂ is introduced into the carrier gas introduction pipes 40 and 44.
Gas was introduced and H ₂ S gas was introduced through the gas introduction pipe 49. The composition of the gas immediately before entering the reaction tube is H ₂ : H
₂ S: (C ₅ H ₅ ) ₂ Fe: C ₆ H ₆ = 85.3: 2.
The total flow rate is 6: 168 ml / mi at 6: 0.3: 11.8.
It was n (at room temperature and atmospheric pressure). The temperature of the soaking part is 110
The temperature was 0 ° C., and the produced carbon fibers were collected by using a metal fiber filter as the fiber collecting device 54. High-resolution transmission electron microscope observation of the carbon fibers collected in the reaction tube and by the stainless fiber filter revealed that fine carbon fibers having a diameter of 0.1 μm, a length of about 40 μm, and a hollow diameter of about 40 Å were obtained. The yield at this time was 58%. The hollow diameter of 20 fibers was measured and found to be 6
If it is less than 0Å and the value is statistically processed, 39Å ± 5Å
(95% confidence limit).

【００３５】比較例１ 図２は比較例１に使用した装置の概略系統図である。図
２に示した加熱器７２及び反応管６８は実施例１で使用
したものと同様のものを用いた。また気化器６０にはＣ
_６Ｈ_６を貯えた。反応管の中心には、内径４５ｍｍ、長
さ３００ｍｍのアルミナ製パイプを２つに割って半円状
にした基板７０を置いた。この基板には予め次のような
処理をした。平均粒径１００Åの鉄の超微粒子約１ｇを
１０００ｍｌのアルコールに懸濁し、上澄液を採取しス
プレーにて基板表面に該上澄液を散布して乾燥した。Comparative Example 1 FIG. 2 is a schematic system diagram of the apparatus used in Comparative Example 1. The heater 72 and the reaction tube 68 shown in FIG. 2 were the same as those used in Example 1. The vaporizer 60 has C
Stored ₆ H ₆ . At the center of the reaction tube, an alumina pipe having an inner diameter of 45 mm and a length of 300 mm was divided into two and a semicircular substrate 70 was placed. This substrate was previously processed as follows. About 1 g of ultrafine iron particles having an average particle size of 100 L was suspended in 1000 ml of alcohol, and the supernatant was collected and sprayed onto the surface of the substrate to dry it.

【００３６】まず、ガス導入管６６よりＮ_２ガスを５０
０ｍｌ／ｍｉｎの液量で送りながら加熱器７２を昇温し
た。一定温度に達してからガス導入管６６にはＮ_２ガス
のかわりにＨ_２ガス５００ｍｌ／ｍｉｎを流した。３０
分のガス置換後ガス導入管６６は閉めて、キャリヤガス
導入管６２よりＨ_２ガスを１００ｍｌ／ｍｉｎの流量で
送った。ガス導出管６４におけるガス組成は、Ｈ_２：Ｃ
_６Ｈ_６＝９７．６：２．４で、総流量は１０２．５ｍｌ
／ｍｉｎであった。均熱部の温度は、１０９０℃とし
て、２０分間運転した。加熱器が冷却してから基板を取
出したところ、基板表面に直径０．２μｍ長さ５ｍｍの
炭素繊維が生成していた。基板より炭素繊維を削りとり
高分解能透過型電子顕微鏡で中空内径を２０本につき測
定したところ、１７０ű４２Å（９５％信頼限界）で
あった。First, 50 N ₂ gas is supplied through the gas inlet pipe 66.
The heater 72 was heated while being fed at a liquid volume of 0 ml / min. After reaching a certain temperature, 500 ml / min of H ₂ gas was flowed through the gas introduction pipe 66 instead of N ₂ gas. 30
After the gas replacement for a minute, the gas introduction pipe 66 was closed, and H ₂ gas was sent from the carrier gas introduction pipe 62 at a flow rate of 100 ml / min. The gas composition in the gas outlet pipe 64 is H ₂ : C.
₆ H ₆ = 97.6: 2.4, total flow rate 102.5 ml
It was / min. The temperature of the soaking part was 1090 ° C., and the operation was performed for 20 minutes. When the substrate was taken out after being cooled by the heater, carbon fibers having a diameter of 0.2 μm and a length of 5 mm were formed on the surface of the substrate. When carbon fibers were shaved from the substrate and the hollow inner diameters of 20 pieces were measured with a high resolution transmission electron microscope, it was 170Å ± 42Å (95% confidence limit).

【００３７】比較例２ Ｆｅ（ＮＯ_３）_３１ｇを１０００ｍｌのアルコールに溶
解し、比較例１に使用した。アルミナ製基板に塗り、比
較例１と同様の手順で炭素繊維を作った。生成した繊維
は直径０．２μｍ長さ約６ｍｍで２０本の繊維について
高分解能透過型電子顕微鏡で中空内径を測定したとこ
ろ、８１ű２３Å（９５％信頼限界）であった。Comparative Example 2 1 g of Fe (NO ₃ ) ₃ was dissolved in 1000 ml of alcohol and used in Comparative Example 1. It was applied to an alumina substrate, and carbon fibers were produced in the same procedure as in Comparative Example 1. The produced fiber had a diameter of 0.2 μm and a length of about 6 mm, and the hollow inner diameter of 20 fibers was measured by a high-resolution transmission electron microscope and found to be 81Å ± 23Å (95% confidence limit).

【００３８】実施例２ Ｈ_２：Ｈ_２Ｓ：（Ｃ_５Ｈ_５）_２Ｆｅ：Ｃ_６Ｈ_６＝７４：
３．０：３．０：１５．２ 総流量１３５０ｍｌ／ｍｉｎとした他実施例１と同様。
得られた繊維は直径０．３μｍ、長さ１３μｍであり、
２０本の繊維の中空内径の測定結果は４８ű７Å（９
５％信頼限界）であった。６０Å以上は１本であった。Example 2 H ₂ : H ₂ S: (C ₅ H ₅ ) ₂ Fe: C ₆ H ₆ = 74:
3.0: 3.0: 15.2 Same as Example 1 except that the total flow rate was 1350 ml / min.
The fiber obtained has a diameter of 0.3 μm and a length of 13 μm,
The measurement result of the hollow inside diameter of 20 fibers is 48Å ± 7Å (9
5% confidence limit). There was one for 60 Å and above.

【００３９】実施例３ 実施例１で得られた炭素繊維をそれぞれＪＩＳ．Ｋ−７
１１３に従う引張試験法により試験した。引張試験は次
の条件で行った。Example 3 The carbon fibers obtained in Example 1 were each manufactured according to JIS. K-7
Tested by the tensile test method according to 113. The tensile test was performed under the following conditions.

【００４０】(1) マトリックスプラスチック：シェアケ
ミカル社製のエポキシエピコート８２８の１００重量部
に対し５重量部のＢＦ_３ＭＥＡを混合したものを使用し
た。(1) Matrix plastic: A mixture of 5 parts by weight of BF ₃ MEA with 100 parts by weight of Epoxy Epicoat 828 manufactured by Shear Chemical Co. was used.

【００４１】(2) 炭素繊維の表面処理：アルゴス中で２
９００℃３０分の熱処理後リフラックス濃硝酸で５時間
にわたり表面処理をした。(2) Surface treatment of carbon fiber: 2 in Argos
After heat treatment at 900 ° C. for 30 minutes, surface treatment was performed with reflux concentrated nitric acid for 5 hours.

【００４２】(3) Ｖ_ｆ（複合材料中の繊維の占める体積
割合）２５％(3) V _f (volume ratio of fibers in composite material) 25%

【００４３】(4) 硬化法：１２５℃かつ圧力１０ｋｇ／
ｍｍ^２の条件下で１時間硬化させた。(4) Curing method: 125 ° C. and pressure 10 kg /
It was cured under conditions of mm ² for 1 hour.

【００４４】比較例３ 比較例２で得た炭素繊維につき、実施例２と同様の方法
で試験した。試験の結果を表１に示す。Comparative Example 3 The carbon fiber obtained in Comparative Example 2 was tested in the same manner as in Example 2. The test results are shown in Table 1.

【００４５】[0045]

【表１】 [Table 1]

【００４６】上記の結果から、中空内径９０％以上が６
０Å以下である本発明による浮遊気相成長炭素繊維は優
れた機械的性質を有することが判る。From the above results, the hollow inner diameter of 90% or more is 6
It can be seen that the floating vapor-grown carbon fiber according to the present invention, which is 0 Å or less, has excellent mechanical properties.

【００４７】実施例４ 混合ガスとして水素：アセチレン：（Ｃ_５Ｈ_５）_２Ｎｉ
＝８４．５：１５．０：０．５、総流量１１００ｍｌ／
分（２５℃換算）、電気炉温度１０８０℃の条件で実施
し、炭素繊維（径×長さ）０．２μｍ×３６μｍの流動
気相成長炭素繊維が得られた。繊維２０本につき中空径
を計測したところ、全て６０Å以下であり値を統計的に
処理すると、４１ű５Å（９５％信頼限界）であっ
た。Example 4 Hydrogen: acetylene: (C ₅ H ₅ ) ₂ Ni as a mixed gas
= 84.5: 15.0: 0.5, total flow rate 1100 ml /
Min (25 ° C. conversion) and the electric furnace temperature was 1080 ° C., and a carbon fiber (diameter × length) of 0.2 μm × 36 μm was obtained. When the hollow diameters of 20 fibers were measured, all were 60Å or less, and when the values were statistically processed, they were 41Å ± 5Å (95% confidence limit).

【００４８】実施例５ 混合ガスとして窒素：ベンゾチオフエン：〔Ｃ_５Ｈ_５Ｆ
ｅ（ＣＯ）_２〕_２＝９５．６：３．４：１．０、総流量
１０８０ｍｌ／分（２５℃換算）、電気炉温度１０６５
℃の条件で実施し、炭素繊維（径×長さ）０．１μｍ×
２７．０μｍの流動気相成長炭素繊維が得られた。繊維
２０本につき中空径を計測したところ、全て６０Å以下
であり値を統計的に処理すると、４７ű６Å（９５％
信頼限界）であった。Example 5 Nitrogen as a mixed gas: benzothiophene: [C ₅ H ₅ F
e (CO) ₂ ] ₂ = 95.6: 3.4: 1.0, total flow rate 1080 ml / min (25 ° C. conversion), electric furnace temperature 1065
Conducted under the condition of ℃, carbon fiber (diameter × length) 0.1μm ×
A 27.0 μm fluidized vapor grown carbon fiber was obtained. When the hollow diameters of 20 fibers were measured, they were all less than 60Å, and when the values were statistically processed, 47Å ± 6Å (95%
(Confidence limit).

【００４９】実施例６ 混合ガスとしてアルゴン：ＣＨ_４：Ｃ_６Ｈ_１５ＳｃＣ_４
Ｈ_１０Ｏ＝９３．２：６．１：０．７、総流量１１００
ｍｌ／分（２５℃換算）、電気炉温度１０６５℃の条件
で実施し、炭素繊維（径×長さ）０．２μｍ×２．０μ
ｍの流動気相成長炭素繊維が得られた。繊維２０本につ
き中空径を計測したところ、全て６０Å以下であり値を
統計的に処理すると、５１ű５Å（９５％信頼限界）
であった。Example 6 Argon: CH ₄ : C ₆ H ₁₅ ScC ₄ as a mixed gas
_{H 10 O = 93.2: 6.1:} 0.7, the total flow rate of 1100
ml / min (25 ° C conversion), electric furnace temperature 1065 ° C, carbon fiber (diameter x length) 0.2 μm × 2.0 μ
m of fluidized vapor grown carbon fiber was obtained. When the hollow diameters of 20 fibers were measured, they were all less than 60Å, and when the values were statistically processed, 51Å ± 5Å (95% confidence limit)
Met.

【００５０】実施例７ 混合ガスとして水素：チオフエン：Ｃ_１０Ｈ_１０Ｂｒ_２
Ｚｒ＝９３．４：６．１：０．５、総流量１２００ｍｌ
／分（２５℃換算）、電気炉温度１０８０℃の条件で実
施し、炭素繊維（径×長さ）０．２μｍ×１．３μｍの
流動気相成長炭素繊維が得られた。繊維２０本につき中
空径を計測したところ、全て６０Å以下であり値を統計
的に処理すると、４８ű７Å（９５％信頼限界）であ
った。Example 7 Hydrogen: thiophene: C ₁₀ H ₁₀ Br ₂ as a mixed gas
Zr = 93.4: 6.1: 0.5, total flow rate 1200 ml
/ Min (converted at 25 ° C) and the electric furnace temperature was 1080 ° C, and a fluidized vapor grown carbon fiber having carbon fibers (diameter x length) of 0.2 µm × 1.3 µm was obtained. When the hollow diameters of 20 fibers were measured, all were 60Å or less, and when the values were statistically processed, they were 48Å ± 7Å (95% confidence limit).

【００５１】実施例８ 混合ガスとして水素：ベンゼン：Ｃ_１０Ｈ_１０Ｖ＝８
１．９：１８．０：０．１、総流量１１００ｍｌ／分
（２５℃換算）、電気炉温度１０８０℃の条件で実施
し、炭素繊維（径×長さ）０．５μｍ×２．５μｍの流
動気相成長炭素繊維が得られた。繊維２０本につき中空
径を計測したところ、全て６０Å以下であり値を統計的
に処理すると、３８ű５Å（９５％信頼限界）であっ
た。Example 8 Hydrogen: benzene: C ₁₀ H ₁₀ V = 8 as a mixed gas
1.9: 18.0: 0.1, total flow rate 1100 ml / min (25 ° C. conversion), electric furnace temperature 1080 ° C., carbon fiber (diameter × length) 0.5 μm × 2.5 μm A fluidized vapor grown carbon fiber was obtained. When the hollow diameters of 20 fibers were measured, all were 60Å or less, and when the values were statistically processed, they were 38Å ± 5Å (95% confidence limit).

【００５２】実施例９ 混合ガスとして水素：アセチレン：（Ｃ_６Ｈ_６）_２Ｍｏ
＝８９．０：１０．０：１．０、総流量１１３０ｍｌ／
分（２５℃換算）、電気炉温度１０７０℃の条件で実施
し、炭素繊維（径×長さ）０．３μｍ×３．０μｍの流
動気相成長炭素繊維が得られた。繊維２０本につき中空
径を計測したところ、１９本が６０Å以下であり値を統
計的に処理すると、５１ű４Å（９５％信頼限界）で
あった。Example 9 Hydrogen as a mixed gas: acetylene: (C ₆ H ₆ ) ₂ Mo
= 89.0: 10.0: 1.0, total flow rate 1130 ml /
Min (25 ° C. conversion) and the electric furnace temperature was 1070 ° C. to obtain a fluidized vapor grown carbon fiber having a carbon fiber (diameter × length) of 0.3 μm × 3.0 μm. When the hollow diameter of 20 fibers was measured, 19 fibers were 60 Å or less, and when the value was statistically processed, it was 51 Å ± 4 Å (95% confidence limit).

【００５３】実施例１０ 混合ガスとして水素：Ｃ_２Ｈ_５ＯＨ：（Ｃ_５Ｈ_５）_２Ｒ
ｅＨ＝８９．３：１０．０：０．７、総流量１０６０ｍ
ｌ／分（２５℃換算）、電気炉温度１０９０℃の条件で
実施し、炭素繊維（径×長さ）０．３μｍ×３．５μｍ
の流動気相成長炭素繊維が得られた。繊維２０本につき
中空径を計測したところ、全て６０Å以下であり値を統
計的に処理すると、５０ű４Å（９５％信頼限界）で
あった。Example 10 Hydrogen as a mixed gas: C ₂ H ₅ OH: (C ₅ H ₅ ) ₂ R
eH = 89.3: 10.0: 0.7, total flow rate 1060 m
Carbon fiber (diameter x length) 0.3 μm x 3.5 μm, carried out under the conditions of 1 / min (25 ° C. conversion) and electric furnace temperature 1090 ° C.
A fluidized vapor grown carbon fiber was obtained. When the hollow diameters of 20 fibers were measured, all were 60Å or less, and when the values were statistically processed, they were 50Å ± 4Å (95% confidence limit).

【００５４】実施例１１ 混合ガスとして水素：酸素：（Ｃ_９Ｈ_７）_２Ｆｅ：Ｃｂ
＝８２．３：０．５：０．２：１７．０、総流量１０９
０ｍｌ／分（２５℃換算）、電気炉温度１０６５℃の条
件で実施し、収率６０％、炭素繊維（径×長さ）０．１
μｍ×５μｍの流動気相成長炭素繊維が得られた。繊維
２０本につき中空径を計測したところ、全て６０Å以下
であり値を統計的に処理すると、３７ű４Å（９５％
信頼限界）であった。Example 11 Hydrogen: oxygen: (C ₉ H ₇ ) ₂ Fe: Cb as a mixed gas
= 82.3: 0.5: 0.2: 17.0, total flow rate 109
It was carried out under the conditions of 0 ml / min (25 ° C. conversion) and electric furnace temperature of 1065 ° C., yield 60%, carbon fiber (diameter × length) 0.1.
A fluidized vapor grown carbon fiber of μm × 5 μm was obtained. When the hollow diameters of 20 fibers were measured, they were all less than 60Å, and when the values were statistically processed, 37Å ± 4Å (95%
(Confidence limit).

【００５５】実施例１２ 混合ガスとして、水素：酸素：（Ｃ_９Ｈ_７）_２Ｆｅ：Ｃ
Ｈ_４＝８０．０：０．５：２．５：１７．０とした他、
実施例１０と同様で行った。この結果、収率３８％、
０．３μｍ×１７μｍ、中空径５５ű６Å（９５％信
頼限界）であった。Example 12 As a mixed gas, hydrogen: oxygen: (C ₉ H ₇ ) ₂ Fe: C
H ₄ = 80.0: 0.5: 2.5: 17.0, and
The same procedure as in Example 10 was performed. As a result, the yield is 38%,
It had a diameter of 0.3 μm × 17 μm and a hollow diameter of 55Å ± 6Å (95% confidence limit).

【００５６】[0056]

【発明の効果】炭素繊維の中空内径を、その９０％以上
が３０〜６０Åにすることにより、炭素繊維の緻密度を
高め、機械的特性が上昇する。また、中空内径が本発明
の実施例のように小さくなることによって、比表面積の
大きい微細な炭素繊維の製造も可能となり、複合材料用
素材としてのメリットが増大する。EFFECTS OF THE INVENTION By making the hollow inner diameter of carbon fiber 90% or more to 30 to 60 Å, the density of carbon fiber is increased and the mechanical properties are increased. Further, since the hollow inner diameter becomes smaller as in the embodiment of the present invention, it becomes possible to manufacture fine carbon fibers having a large specific surface area, and the merit as a raw material for composite materials increases.

【００５７】実施例１〜１２で得られた炭素繊維を透過
型電子顕微鏡写真によって観察した結果、該炭素繊維は
先端に３０〜６０Åの球形超微粒子を有し、繊維の中央
に繊維軸にそって中空を有することがわかった。As a result of observing the carbon fibers obtained in Examples 1 to 12 with a transmission electron microscope photograph, the carbon fibers had spherical ultrafine particles of 30 to 60Å at the tip, and the carbon fibers were gently aligned with the fiber axis at the center. It was found to have a hollow.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明に係る流動気相成長法による中空炭素繊
維の製造に使用する装置の一実施例を示す概略系統図で
ある。FIG. 1 is a schematic system diagram showing an embodiment of an apparatus used for producing hollow carbon fibers by a fluidized vapor phase growth method according to the present invention.

【図２】従来の気相法による炭素繊維の製造に使用する
一般的装置の概略系統図である。FIG. 2 is a schematic system diagram of a general apparatus used for producing carbon fiber by a conventional vapor phase method.

【符号の説明】[Explanation of symbols]

４０，４４ キャリヤガス導入管 ４２ 有機金属化合物用気化器 ４６ 炭素化合物用気化器 ４８ 混合ガス供給管 ４９ ガス導入管 ５０ 反応管 ５２ 加熱器 ５４ 繊維捕集装置 ５６ 管 ６０ 気化器 ６２ キャリヤガス導入管 ６４ ガス導出管 ６６ ガス導入管 ６８ 反応管 ７０ 基板 ７２ 加熱器 ７４ ガス導出管 40,44 Carrier gas introducing pipe 42 Vaporizer for organometallic compound 46 Vaporizer for carbon compound 48 Mixed gas supply pipe 49 Gas introducing pipe 50 Reaction pipe 52 Heater 54 Fiber collecting device 56 Pipe 60 Vaporizer 62 Carrier gas introducing pipe 64 gas outlet pipe 66 gas inlet pipe 68 reaction pipe 70 substrate 72 heater 74 gas outlet pipe

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 一群の流動気相成長炭素繊維において、
その９０％以上が３０〜６０Åの中空内径を有すること
を特徴とする中空炭素繊維。1. A group of fluidized vapor grown carbon fibers comprising:
90% or more of the hollow carbon fibers have a hollow inner diameter of 30 to 60Å.