JP2002146634A - Fine carbon fiber and method for producing the same - Google Patents
Fine carbon fiber and method for producing the sameInfo
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- JP2002146634A JP2002146634A JP2000381067A JP2000381067A JP2002146634A JP 2002146634 A JP2002146634 A JP 2002146634A JP 2000381067 A JP2000381067 A JP 2000381067A JP 2000381067 A JP2000381067 A JP 2000381067A JP 2002146634 A JP2002146634 A JP 2002146634A
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- carbon fiber
- fine carbon
- cylindrical
- fine
- carbon
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は特異な構造を持つ微
細炭素繊維、その製法及び応用に関し、特に樹脂、ゴム
等複合材のフィラー、半導体材料、触媒、あるいは電界
電子放出材料として適した微細炭素繊維及びその製法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine carbon fiber having a peculiar structure, a method for producing the same, and its application, particularly, a fine carbon fiber suitable as a filler for a composite material such as resin and rubber, a semiconductor material, a catalyst, or a field electron emission material. The present invention relates to a fiber and a method for producing the fiber.
【０００２】[0002]
【従来の技術】炭素繊維は、その高強度、高弾性率、高
導電性等の優れた特性から各種の複合材料に使用されて
いる。従来から応用されてきた優れた機械的特性ばかり
でなく、炭素繊維あるいは炭素材料に備わった導電性を
生かし、近年のエレクトロニクス技術の発展に伴い、電
磁波シールド材、静電防止材用の導電性樹脂フィラーと
して、あるいは樹脂への静電塗装のためのフィラーとし
ての用途が期待されてきている。また、炭素材料として
の化学的安定性、熱的安定性と微細構造との特徴を生か
し、フラットディスプレー等の電界電子放出材料として
の用途が期待されている。2. Description of the Related Art Carbon fibers are used in various composite materials because of their excellent properties such as high strength, high elastic modulus and high conductivity. Utilizing not only the excellent mechanical properties that have been applied in the past, but also the conductive properties of carbon fiber or carbon materials, with the development of electronics technology in recent years, conductive resins for electromagnetic wave shielding and antistatic materials have been developed. It is expected to be used as a filler or as a filler for electrostatic coating on a resin. In addition, it is expected to be used as a field electron emission material such as a flat display by utilizing the characteristics of chemical stability, thermal stability and microstructure as a carbon material.
【０００３】従来の炭素繊維は、ＰＡＮ、ピッチ、セル
ロース等の繊維を熱処理し炭化することにより製造する
いわゆる有機系カーボンファイバーとして生産されてい
る。これらを繊維強化複合材のフィラーとして用いる場
合、母材との接触面積を大きくするために、径を細くす
ること、長さを長くすること等が補強効果を上げるため
に望ましい。また、母材との接着性を改善するために
は、炭素繊維の表面が滑らかでなく、ある程度荒れてい
る方が好ましく、このために空気中で高温に晒し酸化さ
せたり、表面にコーティングを施こしたり等の表面処理
が行なわれている。Conventional carbon fibers are produced as so-called organic carbon fibers produced by heat-treating and carbonizing fibers such as PAN, pitch, and cellulose. When these are used as fillers of a fiber-reinforced composite material, it is desirable to increase the contact area with the base material, to reduce the diameter, to increase the length, etc., in order to enhance the reinforcing effect. In order to improve the adhesiveness with the base material, it is preferable that the surface of the carbon fiber is not smooth but rough to some extent. For this reason, the carbon fiber is exposed to high temperature in the air to be oxidized, or the surface is coated. Surface treatment such as rubbing is performed.
【０００４】しかし、これらの炭素繊維は、その原料と
なる有機繊維の糸径が５〜１０μｍ程度であり、径の小
さい、炭素繊維の製造は不可能であった。また、径に対
する長さの比（アスペクト比）に限界があり、細くてア
スペクト比の大きい炭素繊維が要望されていた。However, these carbon fibers have a yarn diameter of about 5 to 10 μm of an organic fiber as a raw material, and it has been impossible to produce carbon fibers having a small diameter. Further, there is a limit to the ratio of length to diameter (aspect ratio), and there has been a demand for thin carbon fibers having a large aspect ratio.
【０００５】また、自動車ボディーへの樹脂の使用、あ
るいは電子機器への樹脂・ゴム等の使用に関しては、金
属並の導電性を要求され、これに伴い、フィラー材とし
ての炭素繊維もこれら各種導電性塗料、導電性樹脂など
の要求を満たすために導電性を上げる必要が出てきた。
そのための手段として、黒鉛化することでこれら特性を
向上させる必要があり、このために更に高温での黒鉛化
処理が行なわれるのが通例である。しかし、この黒鉛化
処理によっても金属並の導電性は得られず、これを補う
ために配合量を多くすると加工性や機械的特性が低下す
るという問題が生じ、繊維自体の更なる導電性の改良、
繊維の細径化による強度の向上等が必要とされてきた。
また、電界電子放出材料としては、従来スピント法によ
る電界電子放出が研究開発されてきたが、その製法には
多くの工程が必要であり、かつ、従来電子放出部にはＭ
ｏ等を用いて先端を針状に加工して用いているが、ディ
スプレーの電子放出材料として用いた場合には、化学
的、熱的に不十分であった。[0005] The use of a resin for an automobile body or the use of a resin or rubber for an electronic device is required to have the same conductivity as that of a metal. It has become necessary to increase conductivity in order to satisfy the requirements for conductive paints and conductive resins.
As a means for achieving this, it is necessary to improve these characteristics by graphitization, and for this purpose, a graphitization treatment at a higher temperature is usually performed. However, even this graphitization does not provide the same level of conductivity as metal, and if the blending amount is increased to compensate for this, the workability and mechanical properties will decrease. Improvement,
It has been required to improve the strength by reducing the diameter of the fiber.
As a field emission material, field emission by the Spindt method has been conventionally researched and developed. However, the manufacturing method requires many steps, and the conventional electron emission portion has M
Although the tip is processed into a needle shape using o or the like, when it is used as an electron emission material for a display, it is insufficient chemically and thermally.
【０００６】その後、１９８０年代後半に、これら有機
系繊維と製法を全く異にするものとして、気相法炭素繊
維（Ｖａｐｏｒ Ｇｒｏｗｎ Ｃａｒｂｏｎ Ｆｉｂｅ
ｒ；以下ＶＧＣＦと略す。）が研究されるようになっ
た。このＶＧＣＦは、炭化水素等のガスを有機遷移金属
系触媒の存在下で気相熱分解することによって直径１μ
ｍ以下、数１００ｎｍまでの炭素繊維が得られることが
知られている。たとえば、ベンゼン等の有機化合物を原
料とし、触媒としてのフェロセン等の有機遷移金属化合
物をキャリアーガスとともに高温の反応炉に導入し、基
盤上に生成させる方法（特開昭６０−２７７００号公
報）、浮遊状態でＶＧＣＦを生成させる方法（特開昭６
０−５４９９８号公報）、あるいは反応炉壁に成長させ
る方法（特許２７７８４３４号）等が開示されている。[0006] Then, in the late 1980's, a vapor production carbon fiber (Vapor Carbon Carbon Fiber) was used as a completely different production method from these organic fibers.
r; hereinafter abbreviated as VGCF. ) Began to be studied. This VGCF has a diameter of 1 μm by subjecting a gas such as a hydrocarbon to gas phase pyrolysis in the presence of an organic transition metal catalyst.
It is known that carbon fibers of m or less and up to several 100 nm can be obtained. For example, a method in which an organic compound such as benzene is used as a raw material, and an organic transition metal compound such as ferrocene as a catalyst is introduced into a high-temperature reactor together with a carrier gas to form the compound on a substrate (Japanese Patent Laid-Open No. 60-27700). Method of generating VGCF in a floating state
No. 0-54998), or a method of growing on a reactor wall (Japanese Patent No. 2778434).
【０００７】これら製法によれば、比較的細くて導電性
に優れ、アスペクト比の大きいフィラー材に適した炭素
繊維が得られるようになり、１００〜２００ｎｍ程度の
径で、アスペクト比１０〜５００程度のものが量産化さ
れ、導電性フィラー材として樹脂用フィラーや鉛蓄電池
の添加材等に使用されるようになった。According to these production methods, carbon fibers suitable for a filler material having a relatively small thickness and excellent conductivity and having a large aspect ratio can be obtained, and have a diameter of about 100 to 200 nm and an aspect ratio of about 10 to 500. Has been mass-produced, and has been used as a conductive filler material in resin fillers and as an additive for lead-acid batteries.
【０００８】これらＶＧＣＦは、形状や結晶構造に特徴
があり、炭素六角網面の結晶が年輪状に円筒形に巻かれ
積層した構造を示し、その中心部には極めて細い中空部
を有する繊維である。しかし、これらＶＧＣＦについて
は、量産規模では１００ｎｍ未満の更に細い径のものは
製造できなかった。[0008] These VGCFs are characterized in shape and crystal structure, and have a structure in which hexagonal carbon crystals are rolled into a cylindrical shape in a ring shape and stacked in a ring shape, and a fiber having an extremely thin hollow portion at the center. is there. However, as for these VGCFs, those with a smaller diameter of less than 100 nm could not be produced on a mass production scale.
【０００９】また、このＶＧＣＦよりも更に細い炭素繊
維として、飯島らによりヘリウムガス中でアーク放電に
より炭素電極を蒸発させた煤の中から、多層カーボンナ
ノチューブが発見された。この多層カーボンナノチュー
ブの直径は、１ｎｍ〜３０ｎｍであり、ＶＧＣＦと同様
に炭素六角網面の結晶が繊維の軸を中心に年輪状に幾重
にも重なり円筒状に閉じられており、その中心部に中空
径を有する微細炭素繊維である。As a carbon fiber finer than the VGCF, multi-walled carbon nanotubes were discovered by Iijima et al. From soot obtained by evaporating a carbon electrode by arc discharge in helium gas. The diameter of this multi-walled carbon nanotube is 1 nm to 30 nm, and like the VGCF, the crystals of the carbon hexagonal plane are superimposed on the axis of the fiber in a number of rings and closed in a cylindrical shape. It is a fine carbon fiber having a hollow diameter.
【００１０】このアーク放電を使用する方法について
は、その製法から量産には向かず実用化には至っていな
い。The method using this arc discharge is not suitable for mass production due to its production method and has not been put to practical use.
【００１１】一方、気相法によるものは大きなアスペク
ト比、高導電性の可能性があり、この方法を改良し、よ
り細い炭素繊維を製造しようとする試みがなされてい
る。米国特許第４６６３２３０号、特公平３−６４６０
６号公報では、約３．５〜７０ｎｍの径でアスペクト比
１００以上の黒鉛質からなる円柱状の炭素フィブリルが
開示されている。その構造は、規則的に配列した炭素原
子の連続層が多層にわたり円柱軸に対し同心的に配列さ
れ、炭素原子の各層のＣ軸がフィブリルの円柱軸に実質
的に直交しており、全体に熱分解により析出する熱炭素
被膜を含まず、滑らかな表面を持っているものである。On the other hand, the vapor phase method has a large aspect ratio and a high conductivity, and attempts have been made to improve this method to produce finer carbon fibers. U.S. Pat. No. 4,663,230, Japanese Patent Publication No. 3-6460
No. 6 discloses a columnar carbon fibril made of graphite having a diameter of about 3.5 to 70 nm and an aspect ratio of 100 or more. The structure is such that a continuous layer of regularly arranged carbon atoms is arranged concentrically with respect to the cylinder axis over multiple layers, and the C axis of each layer of carbon atoms is substantially orthogonal to the cylinder axis of the fibrils. It does not contain a thermal carbon film deposited by thermal decomposition and has a smooth surface.
【００１２】同様に、特開昭６１−７００１４号公報に
は、１０〜５００ｎｍでアスペクト比２〜３００００の
気相法による炭素繊維が紹介されており、熱分解炭素層
の厚みが直径の２０％以下であることが記されている。Similarly, Japanese Patent Application Laid-Open No. 61-70014 discloses a carbon fiber produced by a gas phase method having an aspect ratio of 2 to 30,000 at a wavelength of 10 to 500 nm. It is stated that:
【００１３】上述のこれらの炭素繊維は、いずれも表面
が滑らかなため接着性、濡れ性、親和性に乏しく、複合
材料として用いる場合には表面を十分酸化処理する等の
表面処理が必要になってくる。また、電界電子放出材料
として用いる場合には、先端を細くする必要がある。[0013] The above-mentioned carbon fibers have a smooth surface and thus poor adhesion, wettability and affinity. When used as a composite material, surface treatment such as sufficient oxidation treatment of the surface is required. Come. Further, when it is used as a field electron emission material, it is necessary to make the tip thin.
【００１４】[0014]
【発明が解決しようとする課題】本発明においては、導
電性の良い４００ｎｍ未満、特に２〜３００ｎｍのフィ
ラー材として樹脂等への接着性の良い微細な炭素繊維を
量産規模で得ること、また、化学的及び熱的に安定で電
子の放出特性に優れ、寿命の長い電界電子放出材料を得
ることが目的である。In the present invention, a fine carbon fiber having good adhesion to a resin or the like is obtained on a mass production scale as a filler material having good conductivity of less than 400 nm, particularly 2 to 300 nm. An object of the present invention is to obtain a field emission material which is chemically and thermally stable, has excellent electron emission characteristics, and has a long life.
【００１５】[0015]
【課題を解決するための手段】本発明者らは、従来から
のＶＧＣＦの製法を発展させ、従来とは違った構造を持
つ新しい微細炭素繊維及びその製造方法を完成した。す
なわち （１）円筒状の炭素シートが重なり合い多層構造をな
し、その中心軸が中空構造であり、外径２〜３００ｎ
ｍ、アスペクト比１０〜１５０００である微細炭素繊維
であって、該炭素繊維の先端部において少なくとも１層
の円筒状炭素シートが前記多層間で折り返して別の円筒
状炭素シートと連続して、その折り返して連続する円筒
状炭素シートが先端部で開いている円筒構造を形成して
いることを特徴とする微細炭素繊維。 （２）折り返して連続する円筒状炭素シートが、多層構
造の外周部に存在することを特徴とする（１）に記載の
微細炭素繊維。 （３）折り返して連続する円筒状炭素シートが形成する
円筒構造の内側に、先端部が閉じている円筒状炭素シー
トが存在することを特徴とする（２）に記載の微細炭素
繊維。 （４）先端部が閉じた円筒状炭素シートの内側にさら
に、先端部で折り返して連続し合い炭素繊維の先端部で
開いた円筒状を成す円筒状炭素シートが存在することを
特徴とする（３）に記載の微細炭素繊維。 （５）外径２〜３００ｎｍ、アスペクト比１０〜１５０
００の微細炭素繊維中に、（１）〜（４）に記載の微細
炭素繊維が５質量％以上を占めることを特徴とする微細
炭素繊維。 （６）外径２〜３００ｎｍ、アスペクト比１０〜１５０
００の微細炭素繊維中に、微細炭素繊維が、５〜９０質
量％を占めることを特徴とする（５）に記載の微細炭素
繊維。 （７）外径２〜３００ｎｍ、アスペクト比１０〜１５０
００の微細炭素繊維中に、透過型電子顕微鏡にて観察さ
れる（１）〜（６）記載の微細炭素繊維が、３〜８０体
積％を占めることを特徴とする微細炭素繊維。 （８）微細炭素繊維が気相法炭素繊維であることを特徴
とする（１）〜（７）記載の微細炭素繊維。 （９）ホウ素元素が炭素繊維に含まれたことを特徴とす
る（１）〜（８）に記載の微細炭素繊維。 （１０）ホウ素元素が炭素繊維の炭素元素と一部置換し
たことを特徴とする（１）〜（９）に記載の微細炭素繊
維。 （１１）筒状の炭素シートが重なり合い多層構造をな
し、その中心軸が中空構造である外径２〜３００ｎｍ、
アスペクト比１０〜１５０００の微細炭素繊維を熱処理
することにより（１）〜（１０）に記載の微細炭素繊維
を製造する方法。 （１２）熱処理温度が２０００℃〜３５００℃であるこ
とを特徴とする（１１）に記載の微細炭素繊維の製造方
法。 （１３）筒状の炭素シートが重なり合い多層構造をな
し、その中心軸が中空構造である外径２〜３００ｎｍ、
アスペクト比１０〜１５０００の微細炭素繊維とホウ素
化合物とを混合して熱処理することを特徴とする（１
１）または（１２）に記載の微細炭素繊維の製造方法。Means for Solving the Problems The present inventors have developed a conventional method for producing VGCF, and have completed a new fine carbon fiber having a structure different from the conventional one and a method for producing the same. That is, (1) a cylindrical carbon sheet overlaps to form a multilayer structure, the central axis of which is a hollow structure, and an outer diameter of 2 to 300 n.
m, a fine carbon fiber having an aspect ratio of 10 to 15000, wherein at least one layer of a cylindrical carbon sheet at the tip of the carbon fiber is folded between the multilayers and is continuous with another cylindrical carbon sheet, A fine carbon fiber characterized in that a folded and continuous cylindrical carbon sheet forms a cylindrical structure open at the tip. (2) The fine carbon fiber according to (1), wherein the folded and continuous cylindrical carbon sheet is present on the outer peripheral portion of the multilayer structure. (3) The fine carbon fiber according to (2), wherein a cylindrical carbon sheet having a closed end is present inside a cylindrical structure formed by folding back and forming a continuous cylindrical carbon sheet. (4) Inside the cylindrical carbon sheet having a closed distal end, there is a cylindrical carbon sheet that is folded back at the distal end and forms a cylindrical shape that is continuous and opens at the distal end of the carbon fiber. Fine carbon fibers according to 3). (5) Outer diameter 2 to 300 nm, aspect ratio 10 to 150
A fine carbon fiber characterized in that the fine carbon fiber according to (1) to (4) accounts for 5% by mass or more of the fine carbon fiber of No. 00. (6) Outer diameter 2 to 300 nm, aspect ratio 10 to 150
The fine carbon fiber according to (5), wherein the fine carbon fiber accounts for 5 to 90% by mass of the fine carbon fiber of No. 00. (7) Outer diameter 2 to 300 nm, aspect ratio 10 to 150
The fine carbon fibers according to (1) to (6), which are observed by a transmission electron microscope in the fine carbon fibers of No. 00, occupy 3 to 80% by volume. (8) The fine carbon fiber according to any one of (1) to (7), wherein the fine carbon fiber is a vapor grown carbon fiber. (9) The fine carbon fiber according to any one of (1) to (8), wherein the boron element is contained in the carbon fiber. (10) The fine carbon fiber according to any one of (1) to (9), wherein the boron element is partially substituted with the carbon element of the carbon fiber. (11) an outer diameter of 2 to 300 nm, in which a cylindrical carbon sheet overlaps to form a multilayer structure, and the central axis of which is a hollow structure;
The method for producing fine carbon fibers according to (1) to (10) by heat-treating fine carbon fibers having an aspect ratio of 10 to 15,000. (12) The method for producing fine carbon fibers according to (11), wherein the heat treatment temperature is 2000 ° C to 3500 ° C. (13) an outer diameter of 2 to 300 nm, in which a cylindrical carbon sheet overlaps to form a multilayer structure, and the central axis thereof is a hollow structure;
It is characterized in that a fine carbon fiber having an aspect ratio of 10 to 15000 and a boron compound are mixed and heat-treated.
The method for producing fine carbon fibers according to 1) or (12).
【００１６】[0016]
【発明の実施の形態】以下、本発明について詳細に説明
する。本発明は、導電性の良い、外径４００ｎｍ未満、
特に２〜３００ｎｍ、さらには１〜８０ｎｍのフィラー
材として樹脂等への接着性の良い、微細な炭素繊維を得
るために、検討を進める中で、微細なＶＧＣＦをホウ素
化合物の存在下で高温熱処理して黒鉛化を図っていたと
き、従来知られていない形態の微細な炭素繊維が得ら
れ、これが導電性が高く、また樹脂等への接着性にも優
れており、さらには化学的及び熱的に安定で電子の放出
特性に優れ、寿命の長い電界電子放出材料を与えるこ
と、またこの新規な形態の微細炭素繊維は熱処理もホウ
素化合物の存在下に限らず得られうるものであることを
見出したものである。本発明の微細炭素繊維は基本的に
より微細でかつより黒鉛化度の高い炭素繊維を製造しよ
うとする過程に得られる１形態の炭素繊維であると理解
される。本発明の微細炭素繊維について説明する。本発
明の微細炭素繊維の特徴を添付図面（図１〜４）を用い
て説明する。これらの図において、模式的に炭素シート
（黒鉛または黒鉛に近い結晶の層）を実線で表す。先ず
従来の１００ｎｍ未満、アスペクト比１０〜１５０００
の微細炭素繊維は、図１の模式断面図に示すように、円
筒状の炭素シートが重なり合い多層構造（年輪構造）を
なし、その中心軸が中空構造であるものが知られている
が、そのような公知の微細炭素繊維は繊維の先端部では
多層構造を構成する円筒状炭素シートは全てがある曲率
をもって閉じている。これに対して、本発明の微細炭素
繊維は下記の如き構造を有する。 １）図２、図４に示す如く、円筒状の炭素シートが重な
り合い多層構造をなし、その中心軸が中空構造であり、
外径２〜３００ｎｍ、アスペクト比１０〜１５０００で
ある微細炭素繊維１０において、該炭素繊維の先端部に
おいて少なくとも１層の円筒状炭素シート１４（１４
ａ，１４ｂ）が前記多層間で折り返して別の円筒状炭素
シート１５（１５ａ，１５ｂ）と連続して、その折り返
して連続する円筒状炭素シート１４、１５が構成する円
筒は炭素繊維の先端部で開いていることを特徴とする微
細炭素繊維。従来の微細な炭素繊維を酸化すると繊維の
先端が強制的に破壊されることがある（米国特許第５，
６４１，４６６号明細書）が、その場合には黒鉛形成条
件ではないので炭素シートが折り返して連続することは
ない。 ２）図２を参照すると、上記１）の微細炭素繊維におい
て、前記折り返して連続する円筒状炭素シート１４，１
５が、多層構造の外周部に存在することを特徴とする微
細炭素繊維。折り返して連続する炭素シートは一般的に
多層構造の外周部に形成され易い。 ３）図２を参照すると、上記２）の微細炭素繊維におい
て、前記折り返して連続する円筒状炭素シート１４、１
５が形成する円筒の内側に、先端部１２Ａが閉じている
円筒状炭素シート１３（１３ａ，１３ｂ）が存在するこ
とを特徴とする微細炭素繊維。一般的に、折り返して連
続する炭素シートが構成する円筒は多層構造の外周部に
存在する傾向があるが、その内側にはさらに円筒状炭素
シートが存在し、その先端部１２Ａは閉じていることが
多い。 ４）図３を参照すると、上記３）の微細炭素繊維におい
て、前記先端部が閉じた円筒状炭素シート１３の内側に
さらに、先端部で折り返して連続し合い炭素繊維の先端
部で開いた円筒状を成す円筒状炭素シート１１，１２が
存在することを特徴とする微細炭素繊維。 ５）図４を参照すると、微細炭素繊維は折り返して連続
する炭素シートが構成する円筒だけからなり、炭素繊維
の先端は開いている形態のものも得られうる。図４の場
合に限らず、微細炭素繊維は折り返して連続する炭素シ
ート１４，１５が構成する円筒において、その内部のど
こかに折り返していない炭素シート１６が存在してもよ
い。 ６）外径２〜３００ｎｍ、アスペクト比１０〜１５００
０の微細炭素繊維中に、上記１）〜５）いずれか記載の
微細炭素繊維が５質量％以上を占める微細炭素繊維。 以上、本発明の微細炭素繊維の代表的な形態を説明した
が、本発明の微細炭素繊維は、炭素繊維の先端部におい
て少なくとも１層の円筒状炭素シートが多層間で折り返
して別の円筒状炭素シートと連続して、その折り返して
連続する円筒状炭素シートが構成する円筒は炭素繊維の
先端部で開いていることを特徴とするものであり、その
他の変化は任意である。例えば、炭素繊維の先端部にお
いて多層間で折り返して別の円筒状炭素シートと連続す
る円筒状炭素シートの層数は、少なくとも１層であれば
よく、２層あるいは３層以上の隣接した円筒状炭素シー
トが折り返して別の円筒状炭素シートと連続していても
よい。また、折り返して連続する円筒状炭素シートどう
しは隣接していても隣接していなくてもよい。例えば、
図４では、円筒状炭素シート１４と円筒状炭素シート１
５が折り返して連続するが、円筒状炭素シート１４と円
筒状炭素シート１５とは間に円筒状炭素シート１６が介
在して相互に隣接していない。また、炭素シートによっ
て構成される炭素繊維の先端部や周囲に不定形炭素が存
在しても、本発明の微細炭素繊維は影響されない。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present invention has good conductivity, an outer diameter of less than 400 nm,
In order to obtain a fine carbon fiber having good adhesion to a resin or the like as a filler material having a thickness of 2 to 300 nm, more preferably 1 to 80 nm, fine VGCF is subjected to high-temperature heat treatment in the presence of a boron compound. When graphitization was carried out, fine carbon fibers in a conventionally unknown form were obtained, which had high conductivity and excellent adhesiveness to resins, etc. To provide a field electron emission material that is stable and has excellent electron emission characteristics and a long life, and that this new form of fine carbon fiber can be heat-treated not only in the presence of boron compounds. It was found. It is understood that the fine carbon fiber of the present invention is basically one type of carbon fiber obtained in the process of producing a finer and more graphitized carbon fiber. The fine carbon fiber of the present invention will be described. The characteristics of the fine carbon fiber of the present invention will be described with reference to the attached drawings (FIGS. 1 to 4). In these figures, a carbon sheet (a layer of graphite or a crystal close to graphite) is schematically represented by a solid line. First, conventional less than 100 nm, aspect ratio 10-15000
As shown in the schematic cross-sectional view of FIG. 1, there is known a fine carbon fiber having a multilayer structure (annular ring structure) in which cylindrical carbon sheets overlap with each other and having a hollow central axis. In such a known fine carbon fiber, the cylindrical carbon sheet constituting the multilayer structure is all closed at a certain curvature at the tip of the fiber. On the other hand, the fine carbon fiber of the present invention has the following structure. 1) As shown in FIGS. 2 and 4, cylindrical carbon sheets overlap to form a multilayer structure, and the central axis thereof is a hollow structure.
In the fine carbon fiber 10 having an outer diameter of 2 to 300 nm and an aspect ratio of 10 to 15000, at least one layer of the cylindrical carbon sheet 14 (14
a, 14b) is folded between the multilayers and is continuous with another cylindrical carbon sheet 15 (15a, 15b). The cylinder formed by the folded and continuous cylindrical carbon sheets 14, 15 is a tip of carbon fiber. Fine carbon fiber characterized by being open in. Oxidation of conventional fine carbon fibers can forcibly break the ends of the fibers (US Pat.
641,466), but in that case, it is not a condition for forming graphite, so that the carbon sheet does not turn back and continue. 2) Referring to FIG. 2, in the fine carbon fiber of the above 1), the folded and continuous cylindrical carbon sheet 14, 1
5. Fine carbon fibers characterized in that 5 is present in the outer peripheral portion of the multilayer structure. The folded and continuous carbon sheet is generally easily formed on the outer peripheral portion of the multilayer structure. 3) Referring to FIG. 2, in the fine carbon fiber of 2), the folded and continuous cylindrical carbon sheet 14, 1
5. A fine carbon fiber, characterized in that a cylindrical carbon sheet 13 (13a, 13b) having a closed end portion 12A is present inside a cylinder formed by 5. In general, a cylinder formed by a continuous carbon sheet that is folded back tends to be present on the outer peripheral portion of the multilayer structure. However, a cylindrical carbon sheet is further present on the inner side, and the tip portion 12A is closed. There are many. 4) Referring to FIG. 3, in the fine carbon fiber of the above 3), the cylindrical portion is further folded back at the front end inside the cylindrical carbon sheet 13 having the closed front end and opened at the front end of the carbon fiber. A fine carbon fiber characterized by having cylindrical carbon sheets 11 and 12 in a shape. 5) Referring to FIG. 4, the fine carbon fiber may be formed only by a cylinder formed by folding and forming a continuous carbon sheet, and the tip of the carbon fiber may be open. The present invention is not limited to the case of FIG. 4, and the carbon sheet 16 which is not folded may exist somewhere inside the cylinder formed of the continuous carbon sheets 14 and 15 by folding the fine carbon fiber. 6) Outer diameter 2 to 300 nm, aspect ratio 10 to 1500
Fine carbon fibers in which the fine carbon fibers according to any one of 1) to 5) above account for 5% by mass or more of the fine carbon fibers. As described above, the typical form of the fine carbon fiber of the present invention has been described. The cylinder formed by the cylindrical carbon sheet which is continuous with the carbon sheet and is turned back and continuous is characterized by being open at the tip of the carbon fiber, and other changes are optional. For example, the number of layers of the cylindrical carbon sheet that is folded between the multilayers at the tip of the carbon fiber and is continuous with another cylindrical carbon sheet may be at least one layer, and may be two or three or more adjacent cylindrical carbon sheets. The carbon sheet may be folded back to be continuous with another cylindrical carbon sheet. The folded and continuous cylindrical carbon sheets may or may not be adjacent to each other. For example,
In FIG. 4, the cylindrical carbon sheet 14 and the cylindrical carbon sheet 1 are shown.
Although 5 is folded back and continued, the cylindrical carbon sheet 14 and the cylindrical carbon sheet 15 are not adjacent to each other with the cylindrical carbon sheet 16 interposed therebetween. In addition, even if amorphous carbon is present at the tip and surroundings of the carbon fiber constituted by the carbon sheet, the fine carbon fiber of the present invention is not affected.
【００１７】本発明の微細炭素繊維は、微細炭素の繊維
部分の構造としては、炭素原子からなる筒状の炭素シー
トが重なり合った多層構造であり、中心軸には中空の空
洞部分が存在する。これらの炭素シートは規則的に配列
した炭素原子が連続したもの、あるいは繊維の長手直角
方向からこれを観察すると、おおむね繊維方向に直線状
に、多重に重なりあっているが、筒状のシートが長手方
向にて途切れて不連続になっている部分があり、また、
中心軸の中空部の内径が一定していなくとも良い。本発
明の微細炭素繊維の上記のような形態は、従来の各種気
相法による炭素繊維では報告されておらず、新規なもの
である。The fine carbon fiber of the present invention has a multilayer structure in which cylindrical carbon sheets made of carbon atoms are overlapped with each other, and a hollow hollow portion is present on the central axis. When these carbon sheets are viewed from the direction perpendicular to the longitudinal direction of the fiber, or a series of regularly arranged carbon atoms, the carbon sheet is almost linearly overlapped in multiple layers, but the cylindrical sheet is There is a discontinuous part in the longitudinal direction,
The inner diameter of the hollow portion of the central shaft may not be constant. The above-described form of the fine carbon fiber of the present invention has not been reported in conventional carbon fibers produced by various vapor phase methods and is novel.
【００１８】これら本発明の微細炭素繊維は、先端に従
来にない異なる特徴を持ち、従来の炭素繊維に対し更に
先端が細くなった部分が存在し、先端が細い導電性物質
の方が電子放出の方向性を持ち、印加電界を集中させる
ことができ、電界電子放出特性が向上し、電界電子放出
素子として適する。また、同様に先端部が異形をしてい
るので導電性フィラー等として使用した場合、樹脂等へ
の接着性が向上する効果がある。また、本微細炭素繊維
を５質量％以上さらに５〜９０質量％、好ましくは１０
〜７０質量％、特に１０〜５０質量％を含むとその構造
の特徴により、電界電子放出特性が向上し、また導電性
フィラー等として使用した場合は、樹脂等への接着性が
向上する効果がある。また、透過型電子顕微鏡による観
察にて、微細炭素繊維の構造は確認できるが、本発明の
微細炭素繊維を３〜８０体積％さらに、５〜７０体積
％、好ましくは１０〜５０体積％含むと電界電子放出特
性が向上し、また導電性フィラー等として使用した場合
は、樹脂等への接着性などが向上する効果がある。The fine carbon fiber of the present invention has a different feature at the tip than ever before, and there is a portion having a tip that is narrower than that of the conventional carbon fiber. , The applied electric field can be concentrated, the field electron emission characteristics are improved, and the device is suitable as a field electron emission device. Similarly, since the tip portion is irregularly shaped, when used as a conductive filler or the like, there is an effect that the adhesiveness to a resin or the like is improved. In addition, the present fine carbon fiber is 5% by mass or more and further 5 to 90% by mass, preferably 10% by mass.
When it is contained in an amount of from 70 to 70% by mass, particularly from 10 to 50% by mass, field emission characteristics are improved by its structural characteristics, and when it is used as a conductive filler or the like, the effect of improving the adhesiveness to a resin or the like is obtained. is there. The structure of the fine carbon fiber can be confirmed by observation with a transmission electron microscope. However, when the fine carbon fiber of the present invention is contained in an amount of 3 to 80% by volume, more preferably 5 to 70% by volume, preferably 10 to 50% by volume. Field electron emission characteristics are improved, and when used as a conductive filler or the like, there is an effect that adhesion to a resin or the like is improved.
【００１９】本発明の微細炭素繊維は、外径が２〜３０
０ｎｍで、アスペクト比１０〜１５０００の微細で長い
繊維が得られるので、フィラー材として多量に添加が可
能であり補強効果に優れるものである。The fine carbon fiber of the present invention has an outer diameter of 2 to 30.
Since fine and long fibers having an aspect ratio of 10 to 15000 can be obtained at 0 nm, a large amount can be added as a filler material and the reinforcing effect is excellent.
【００２０】更に、上記の構造を有するものは炭素シー
トの端面が外部に出ていることから、電池の添加材とし
て使用した場合に、イオンの補足性がよく、また導電性
についても従来の気相法炭素繊維と変わらず、かつ表面
が平滑でないため電池の電解液との濡れ性もよい。従っ
て電池用の添加材として好適であるという特徴を有す
る。本発明の特異な形態を有する微細な炭素繊維は、微
細な炭素繊維であって黒鉛化の高いものを製造する方法
であれば製造される可能性があるが、以下に本発明の微
細な炭素繊維を製造するために好適な方法について説明
する。本発明の微細炭素繊維は、一般的には、遷移金属
触媒を用いて有機化合物、特に炭化水素類を熱分解する
ことにより粗微細炭素繊維を得、それを更に２０００〜
３５００℃、好ましくは２５００〜３５００℃の熱処理
を行うことにより得られる。微細炭素繊維が上記の折り
返し構造をもつ理由は炭素シート間の距離が小さくなる
ためと考えられるので、できるだけ炭素シート間隔を小
さくするような条件を採用することにより、本発明の微
細炭素繊維はより容易に得られる。従って、粗微細炭素
繊維を熱処理する際にホウ素化合物を存在させることが
有利である。ホウ素化合物を共存させると、熱処理温度
を無添加に比べ数百℃低くすることができ、また同じ熱
処理温度では無添加に比べ繊維径に対する外周部分の比
率を大きくすることができる。ホウ素化合物としては、
加熱によりホウ素を生成する物質であればよく、例え
ば、炭化ホウ素、ホウ素酸化物、有機ホウ素酸化物等の
固体、液体、さらには気体でもよい。Further, since the carbon sheet having the above-mentioned structure has the end face of the carbon sheet exposed to the outside, when used as an additive for a battery, it has a good ion-capturing property and has a conventional conductivity. Since it is the same as the phase-processed carbon fiber and the surface is not smooth, it has good wettability with the battery electrolyte. Therefore, it has a feature that it is suitable as an additive for batteries. The fine carbon fiber having a peculiar form of the present invention may be produced by a method for producing a fine carbon fiber having a high degree of graphitization. A preferred method for producing fibers will be described. The fine carbon fiber of the present invention is generally obtained by thermally decomposing organic compounds, particularly hydrocarbons, using a transition metal catalyst to obtain coarse and fine carbon fibers.
It is obtained by performing a heat treatment at 3500 ° C., preferably 2500 to 3500 ° C. The reason why the fine carbon fibers have the above-mentioned folded structure is considered to be because the distance between the carbon sheets is reduced.Therefore, by adopting conditions that make the carbon sheet interval as small as possible, the fine carbon fibers of the present invention are more likely to be formed. Obtained easily. Therefore, it is advantageous that a boron compound is present when the coarse and fine carbon fibers are heat-treated. When a boron compound is present, the heat treatment temperature can be lowered by several hundred degrees centigrade as compared with the case where no boron compound is added, and the ratio of the outer peripheral portion to the fiber diameter can be increased at the same heat treatment temperature as compared with the case where no boron compound is added. As the boron compound,
Any substance that generates boron by heating may be used. For example, a solid, liquid, or gas such as boron carbide, boron oxide, or organic boron oxide may be used.
【００２１】最初に遷移金属触媒を用いて有機化合物、
特に炭化水素類を熱分解することにより粗微細炭素繊維
を得る。有機遷移金属化合物は、触媒となる遷移金属を
含むものである。遷移金属としては、周期律表第ＩＶ
ａ，Ｖａ，ＶＩａ，ＶＩＩａ，ＶＩＩＩ族の金属を含む
有機化合物である。中でもフェロセン、ニッケルセン等
の化合物が好ましい。触媒としての有機遷移金属化合物
の含有量としては、有機化合物の炭素量に対して０．０
１〜１５．０質量％、好ましくは０．０３〜１０．０質
量％、好ましくは０．１〜５．０質量％が良い。またそ
の他、助触媒として硫黄化合物を用いるが、その形態は
特に制限は無く、炭素源である有機化合物に溶解するも
のなら良い。その硫黄化合物として、チオフェンや各種
チオールあるいは、無機硫黄等が用いられる。その使用
量は有機化合物に対して０．０１〜１０．０質量％、好
ましくは、０．０３〜５．０質量％、さらに好ましくは
０．１〜４．０質量％が良い。First, an organic compound using a transition metal catalyst,
In particular, coarse and fine carbon fibers are obtained by thermally decomposing hydrocarbons. The organic transition metal compound contains a transition metal serving as a catalyst. As the transition metal, Periodic Table IV
Organic compounds containing metals of groups a, Va, VIa, VIIa and VIII. Among them, compounds such as ferrocene and nickel sen are preferable. The content of the organic transition metal compound as a catalyst is 0.0
1-15.0 mass%, preferably 0.03-10.0 mass%, preferably 0.1-5.0 mass%. In addition, a sulfur compound is used as a co-catalyst, but the form is not particularly limited, and any form may be used as long as it can be dissolved in an organic compound as a carbon source. As the sulfur compound, thiophene, various thiols, inorganic sulfur or the like is used. The use amount thereof is 0.01 to 10.0% by mass, preferably 0.03 to 5.0% by mass, and more preferably 0.1 to 4.0% by mass based on the organic compound.
【００２２】炭素繊維の原料となる有機化合物は、ベン
ゼン、トルエン、キシレン、メタノール、エタノール、
ナフタレン、フェナントレン、シクロプロパン、シクロ
ペンテン、シクロヘキサン有機化合物や揮発油、灯油等
あるいはＣＯ、天然ガス、メタン、エタン、エチレン、
アセチレン等のガス及びそれらの混合物も可能である。
中でもベンゼン、トルエン、キシレン等の芳香族化合物
が特に好ましい。The organic compounds used as raw materials for carbon fibers include benzene, toluene, xylene, methanol, ethanol,
Naphthalene, phenanthrene, cyclopropane, cyclopentene, cyclohexane organic compounds, volatile oil, kerosene, etc., CO, natural gas, methane, ethane, ethylene,
Gases such as acetylene and mixtures thereof are also possible.
Among them, aromatic compounds such as benzene, toluene and xylene are particularly preferred.
【００２３】キャリヤーガスとしては、通常水素ガスを
はじめとする還元性のガスが使用される。キャリヤーガ
スを予め５００〜１３００℃に加熱しておくことが好ま
しい。加熱する理由は、反応時に触媒の金属の生成と炭
素化合物の熱分解による炭素源の供給を一致させ、反応
を瞬時に起こすようにして、より微細な炭素繊維が得ら
れるようにするためである。キャリアーガスを原料と混
合した際に、キャリアーガスの加熱温度が５００℃未満
では、原料の炭素化合物の熱分解が起こりにくく、１３
００℃をこえると炭素繊維の径方向の成長が起こり、径
が太くなりやすい。As the carrier gas, a reducing gas such as a hydrogen gas is usually used. It is preferred that the carrier gas be heated to 500 to 1300 ° C. in advance. The reason for heating is to match the generation of the metal of the catalyst and the supply of the carbon source by the thermal decomposition of the carbon compound during the reaction, so that the reaction is instantaneously caused and finer carbon fibers are obtained. . When the heating temperature of the carrier gas is less than 500 ° C. when the carrier gas is mixed with the raw material, thermal decomposition of the carbon compound of the raw material hardly occurs and 13
When the temperature exceeds 00 ° C., the carbon fiber grows in the radial direction, and the diameter tends to increase.
【００２４】キャリアーガスの使用量は、炭素源である
有機化合物１．０モル部に対し１〜７０モル部が適当で
ある。炭素繊維の径は、炭素源とキャリアーガスの比率
を変えることにより、制御することが出来る。原料は、
炭素源の有機化合物に遷移金属化合物及び助触媒の硫黄
化合物を溶解し調整する。そして原料は液体のままキャ
リアーガスで噴霧して反応炉へ供給することも出来る
が、キャリアーガスの一部をパージガスとして気化させ
て反応炉へ供給し反応させることも出来る。繊維径の細
い炭素繊維を得る場合は原料は気化して反応炉へ供給し
た方が好ましい。The amount of the carrier gas used is suitably from 1 to 70 mol parts per 1.0 mol part of the organic compound as the carbon source. The diameter of the carbon fiber can be controlled by changing the ratio between the carbon source and the carrier gas. Raw materials are
A transition metal compound and a co-catalyst sulfur compound are dissolved and adjusted in an organic compound as a carbon source. The raw material can be sprayed with a carrier gas in a liquid state and supplied to the reaction furnace. Alternatively, a part of the carrier gas can be vaporized as a purge gas and supplied to the reaction furnace for reaction. When obtaining a carbon fiber having a small fiber diameter, it is preferable that the raw material is vaporized and supplied to the reaction furnace.
【００２５】反応炉は、通常縦型の電気炉を使用する。
反応炉温度は８００〜１３００℃、好ましくは１０００
〜１３００℃である。所定の温度に昇温した反応炉へ、
原料液とキャリアーガスあるいは原料を気化させた原料
ガスとキャリアーガスとを供給し、反応させ炭素繊維を
得る。As the reaction furnace, a vertical electric furnace is usually used.
The reactor temperature is 800-1300 ° C., preferably 1000
１1300 ° C. To the reaction furnace that has been heated to a predetermined temperature,
A raw material liquid and a carrier gas or a raw material gas obtained by vaporizing the raw material and a carrier gas are supplied and reacted to obtain carbon fibers.
【００２６】このようにして反応炉に吹き込まれたガス
が熱分解し、有機化合物は炭素源となり、有機遷移金属
化合物は触媒の遷移金属粒子となり、この遷移金属粒子
を核とした微細炭素繊維の生成が行われる。得られた微
細炭素繊維は、さらに、ヘリウム、アルゴン等の不活性
ガス雰囲気化で、９００〜１５００℃の熱処理を行い、
更に２０００〜３５００℃の熱処理を行う、あるいは、
反応により得られた状態の微細炭素繊維を不活性ガス雰
囲気化、直接２０００〜３５００℃の熱処理を行って、
本発明の特異な微細炭素繊維を得ることが可能である。
しかし、反応により得られた状態の微細炭素に、あるい
はその微細炭素繊維を不活性ガス雰囲気下で９００〜１
５００℃の熱処理を行った後に、炭化ホウ素（Ｂ
４Ｃ）、酸化ホウ素（Ｂ２Ｏ３）、元素状ホウ素、ホウ
酸（Ｈ３ＢＯ３）、ホウ酸塩等のホウ素化合物と混合し
て、更に不活性ガス雰囲気下２０００〜３５００℃で熱
処理を行うことにより、本発明の特異な微細炭素繊維を
より容易に得ることが可能である。ホウ素化合物の添加
量は、用いるホウ素化合物の化学的特性、物理的特性に
依存するために限定されないが、例えば炭化ホウ素（Ｂ
４Ｃ）を使用した場合には、微細炭素繊維に対して０．
０５〜１０質量％、好ましくは０．１〜５質量％の範囲
が良い。微細炭素繊維にホウ素が含まれるとは、ホウ素
が一部固溶して、炭素繊維の表面、炭素六角網面の積層
体層間、中空部内に存在したり、炭素原子とホウ素原子
が一部置換した状態をいう。The gas blown into the reaction furnace in this manner is thermally decomposed, the organic compound serves as a carbon source, the organic transition metal compound serves as transition metal particles of the catalyst, and fine carbon fibers having the transition metal particles as nuclei. Generation occurs. The obtained fine carbon fiber is further subjected to a heat treatment at 900 to 1500 ° C. in an atmosphere of an inert gas such as helium or argon,
Further, a heat treatment at 2000 to 3500 ° C. is performed, or
The fine carbon fiber in the state obtained by the reaction is subjected to an inert gas atmosphere, and directly heat-treated at 2000 to 3500 ° C.
It is possible to obtain the unique fine carbon fiber of the present invention.
However, the fine carbon obtained by the reaction or the fine carbon fiber is 900 to 1 under an inert gas atmosphere.
After heat treatment at 500 ° C., boron carbide (B
4 C), boron oxide (B 2 O 3), elemental boron, boric acid (H 3 BO 3), is mixed with a boron compound such as boric acid salts, further heat-treated under 2,000 to 3,500 ° C. inert gas atmosphere By carrying out, the unique fine carbon fiber of the present invention can be obtained more easily. The addition amount of the boron compound is not limited because it depends on the chemical and physical properties of the boron compound used.
When 4C) is used, 0.1% is used for fine carbon fibers.
The range is from 0.05 to 10% by mass, preferably from 0.1 to 5% by mass. The fact that boron is contained in the fine carbon fiber means that boron is partially dissolved and exists in the surface of the carbon fiber, between layers of the carbon hexagonal mesh plane, in the hollow portion, or partially replaced by carbon atoms and boron atoms. Refers to the state of having done.
【００２７】[0027]
【実施例】以下、本発明の実施例をあげて説明する。概
略図の図５に示すように縦型加熱炉１（内径１７０ｍ
ｍ、長さ１５００ｍｍ）の頂部に、原料気化器５を通し
て気化させた原料を供給する原料供給管４と、キャリア
ーガス供給配管６を取りつけた。原料供給管４からは、
フェロセン３質量％、チオフェン１質量％溶解したトル
エンを気化させ２０ｇ／分で供給し、キャリアーガスと
して水素を用い、７５リットル／分で供給し反応させ
た。この反応で得られた微細炭素繊維の透過型電子顕微
鏡写真を図６に示す。この反応で得られた微細炭素繊維
をＡｒ（アルゴン）雰囲気下１３００℃で熱処理し、更
に１３００℃処理品をＡｒ雰囲気下２８００℃で熱処理
し重量回収率９６％で微細炭素繊維を得た。また、この
微細炭素繊維のＡｒ雰囲気下１３００℃熱処理品に対し
てＢ４Ｃを４質量％混合してＡｒ雰囲気下２８００℃で
熱処理し重量回収率９４％で微細炭素繊維を得た。この
透過型電子顕微鏡写真を図７に示す。図６、図７とも
に、炭素原子からなる筒状の炭素シートが重なりあった
多層構造であり、その中心軸が中空構造である。しか
し、図６では図１の模式図に対応し、先端が閉じている
が、図７ではおおよそ図３の模式図に対応する形態を有
する多層構造が見られる。即ち、図７では、その先端が
開いた円筒を形成している外周部（図３の１４，１５に
対応）と、先端が閉じた中間部（図３の１３に対応）
と、さらにその内側に先端が開いた円筒（図３の１１，
１２に対応）を有する。また、多層構造の外側と内側を
構成するそれぞれの炭素シート（図３の１４，１５と１
１，１２に対応）の末端がお互いに折り返して結合して
連続している。多層構造の外側と内側の折り返した炭素
シートの層の中間をなす炭素シート（図３の１３に対
応）は、先端（図３の１２Ａに対応）が閉じている。な
お、図７では、炭素繊維の先端部において繊維の断面方
向に炭素シートが見えるが、この炭素シートは外周部の
炭素シートの折り返し部分が炭素シートとして見えてい
るものであり、繊維の軸心部に炭素シートが存在するわ
けではない。また、同様に、炭素繊維の先端部におい
て、中間部炭素シートの閉じた先端部の炭素シートの先
が空洞でなく何か物質が存在するように見えるが、この
部分は不定形炭素が付着しているものであり、炭素繊維
の構造には関係ないものである。不定形炭素は炭素繊維
の円周部表面にも存在するのが見られる。Embodiments of the present invention will be described below. As shown in FIG. 5 of the schematic diagram, the vertical heating furnace 1 (inside diameter 170 m
(M, 1500 mm in length), a raw material supply pipe 4 for supplying a raw material vaporized through a raw material vaporizer 5 and a carrier gas supply pipe 6 were attached. From the raw material supply pipe 4,
Toluene in which 3% by mass of ferrocene and 1% by mass of thiophene were dissolved was vaporized and supplied at a rate of 20 g / min. Hydrogen was used as a carrier gas and supplied at a rate of 75 L / min to cause a reaction. FIG. 6 shows a transmission electron micrograph of the fine carbon fiber obtained by this reaction. The fine carbon fiber obtained by this reaction was heat-treated at 1300 ° C. in an Ar (argon) atmosphere, and the product treated at 1300 ° C. was further heat-treated at 2800 ° C. in an Ar atmosphere to obtain a fine carbon fiber at a weight recovery of 96%. Further, 4% by mass of B 4 C was mixed with the heat-treated product of this fine carbon fiber in an Ar atmosphere at 1300 ° C. and heat-treated at 2800 ° C. in an Ar atmosphere to obtain a fine carbon fiber with a weight recovery of 94%. This transmission electron micrograph is shown in FIG. 6 and 7 each have a multilayer structure in which cylindrical carbon sheets made of carbon atoms are overlapped, and the central axis thereof is a hollow structure. However, FIG. 6 corresponds to the schematic diagram of FIG. 1 and the tip is closed, while FIG. 7 shows a multilayer structure having a form roughly corresponding to the schematic diagram of FIG. That is, in FIG. 7, an outer peripheral portion (corresponding to 14 and 15 in FIG. 3) and a middle portion (corresponding to 13 in FIG. 3) having a closed end are formed.
And a cylinder with an open end inside (11,
12). In addition, each of the carbon sheets (14, 15 and 1 in FIG.
(Corresponding to Nos. 1 and 12) are folded back and joined to each other and are continuous. The carbon sheet (corresponding to 13 in FIG. 3), which is located between the folded carbon sheet layers on the outside and inside of the multilayer structure, has a closed end (corresponding to 12A in FIG. 3). In FIG. 7, a carbon sheet can be seen in the cross-sectional direction of the fiber at the tip of the carbon fiber. In this carbon sheet, the folded portion of the carbon sheet in the outer peripheral portion is seen as a carbon sheet, and the axial center of the fiber is There is no carbon sheet in the part. Similarly, at the tip of the carbon fiber, the tip of the carbon sheet at the closed tip of the intermediate carbon sheet appears to be not hollow but some substance is present, but amorphous carbon adheres to this portion. It is not related to the structure of the carbon fiber. It can be seen that amorphous carbon is also present on the circumferential surface of the carbon fiber.
【００２８】このときの繊維の外径は、約１０〜１００
ｎｍでアスペクト比数１０以上の繊維が生産された。ま
た、透過型電子顕微鏡にて観察したところ、上記特徴を
持った繊維が半数以上であった。The outer diameter of the fiber at this time is about 10 to 100.
Fibers with an aspect ratio of tens or more in nm were produced. When observed with a transmission electron microscope, more than half of the fibers had the above characteristics.
【００２９】[0029]
【発明の効果】本発明によれば、従来の炭素繊維や気相
法炭素繊維と異なり、外径が２〜３００ｎｍであり、そ
のアスペクト比が１０〜１５０００で、該炭素繊維の先
端部において少なくとも１層の円筒状炭素シートが前記
多層間で折り返して別の円筒状炭素シートと連続して、
その折り返して連続する円筒状炭素シートが先端部で開
いている円筒を形成していることを特徴とする微細炭素
繊維を提供でき、電界電子放出、気体の吸蔵、樹脂用導
電性フィラーとして有用である。According to the present invention, unlike conventional carbon fibers and vapor grown carbon fibers, the outer diameter is 2 to 300 nm, the aspect ratio is 10 to 15000, and at least the tip of the carbon fiber has One layer of a cylindrical carbon sheet is folded between the multilayers and is continuous with another cylindrical carbon sheet;
The turned back continuous cylindrical carbon sheet forms a cylinder that is open at the tip end, so that it can provide fine carbon fibers, which are useful as field electron emission, gas occlusion, and conductive filler for resin. is there.
【図１】従来の微細炭素繊維の構造を説明するための模
式断面図である。FIG. 1 is a schematic sectional view for explaining the structure of a conventional fine carbon fiber.
【図２】本発明の微細炭素繊維の構造を説明するための
模式断面図である。FIG. 2 is a schematic sectional view for explaining the structure of the fine carbon fiber of the present invention.
【図３】本発明の微細炭素繊維の構造を説明するための
模式断面図である。FIG. 3 is a schematic sectional view for explaining the structure of the fine carbon fiber of the present invention.
【図４】本発明の微細炭素繊維の構造を説明するための
模式断面図である。FIG. 4 is a schematic cross-sectional view for explaining the structure of the fine carbon fiber of the present invention.
【図５】本発明の実施例に示す製造のための装置の概略
図である。FIG. 5 is a schematic view of an apparatus for manufacturing shown in an embodiment of the present invention.
【図６】従来の微細炭素繊維の透過電子顕微鏡写真（倍
率：２０，０００倍）である。FIG. 6 is a transmission electron micrograph (magnification: 20,000 times) of a conventional fine carbon fiber.
【図７】ホウ素化合物を用いて熱処理を行った本発明に
よる微細炭素繊維の熱処理品の透過電子顕微鏡写真（倍
率：２０，０００倍）である。FIG. 7 is a transmission electron micrograph (magnification: 20,000 times) of a heat-treated product of a fine carbon fiber according to the present invention which has been heat-treated using a boron compound.
１…縦型加熱炉 ２…加熱炉用ヒーター ３…原料回収系 ４…原料供給管 ５…原料気化器 ６…キャリヤーガス供給管 DESCRIPTION OF SYMBOLS 1 ... Vertical heating furnace 2 ... Heater heater 3 ... Raw material recovery system 4 ... Raw material supply pipe 5 ... Raw material vaporizer 6 ... Carrier gas supply pipe
───────────────────────────────────────────────────── フロントページの続き (72)発明者 須原 豊 神奈川県川崎市川崎区大川町５−１ 昭和 電工株式会社生産技術センター内 Ｆターム(参考） 4G046 CA02 CB01 CC01 CC03 CC05 CC08 4L037 AT05 CS03 FA02 FA03 FA04 FA05 FA12 PA08 PA13 UA04 UA14 UA20 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yutaka Suhara 5-1 Okawacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko KK Production Technology Center F-term (reference) 4G046 CA02 CB01 CC01 CC03 CC05 CC08 4L037 AT05 CS03 FA02 FA03 FA04 FA05 FA12 PA08 PA13 UA04 UA14 UA20
Claims (13)
造をなし、その中心軸が中空構造であり、外径２〜３０
０ｎｍ、アスペクト比１０〜１５０００である微細炭素
繊維であって、該炭素繊維の先端部において少なくとも
１層の円筒状炭素シートが前記多層間で折り返して別の
円筒状炭素シートと連続して、その折り返して連続する
円筒状炭素シートが先端部で開いている円筒構造を形成
していることを特徴とする微細炭素繊維。A cylindrical carbon sheet overlaps to form a multilayer structure, the central axis of which is a hollow structure, and an outer diameter of 2 to 30.
0 nm, a fine carbon fiber having an aspect ratio of 10 to 15000, wherein at least one layer of a cylindrical carbon sheet at the tip of the carbon fiber is folded between the multilayers to be continuous with another cylindrical carbon sheet, A fine carbon fiber characterized in that a folded and continuous cylindrical carbon sheet forms a cylindrical structure open at the tip.
が、多層構造の外周部に存在することを特徴とする請求
項１に記載の微細炭素繊維。2. The fine carbon fiber according to claim 1, wherein the folded and continuous cylindrical carbon sheet is present on the outer peripheral portion of the multilayer structure.
形成する円筒構造の内側に、先端部が閉じている円筒状
炭素シートが存在することを特徴とする請求項２に記載
の微細炭素繊維。3. The fine carbon fiber according to claim 2, wherein a cylindrical carbon sheet having a closed end is present inside a cylindrical structure formed by folding and forming a continuous cylindrical carbon sheet.
にさらに、先端部で折り返して連続し合い炭素繊維の先
端部で開いた円筒状を成す円筒状炭素シートが存在する
ことを特徴とする請求項３に記載の微細炭素繊維。4. A cylindrical carbon sheet further comprising a cylindrical carbon sheet which is folded back at the distal end and forms a cylindrical shape open at the distal end of the carbon fiber, inside the cylindrical carbon sheet having a closed distal end. The fine carbon fiber according to claim 3, which is used.
〜１５０００の微細炭素繊維中に、請求項１〜４のいず
れかに記載の微細炭素繊維が５質量％以上を占めること
を特徴とする微細炭素繊維。5. An outer diameter of 2 to 300 nm and an aspect ratio of 10.
The fine carbon fiber according to any one of claims 1 to 4, wherein the fine carbon fiber occupies 5% by mass or more of the fine carbon fiber.
〜１５０００の微細炭素繊維中に、微細炭素繊維が、５
〜９０質量％を占めることを特徴とする請求項５に記載
の微細炭素繊維。6. An outer diameter of 2 to 300 nm and an aspect ratio of 10.
15000 fine carbon fibers, 5
The fine carbon fiber according to claim 5, which occupies ~ 90% by mass.
〜１５０００の微細炭素繊維中に、透過型電子顕微鏡に
て観察される請求項１〜６のいずれかに記載の微細炭素
繊維が、３〜８０体積％を占めることを特徴とする微細
炭素繊維。7. An outer diameter of 2 to 300 nm and an aspect ratio of 10.
The fine carbon fiber according to any one of claims 1 to 6, wherein the fine carbon fiber occupies 3 to 80% by volume of the fine carbon fiber observed in a transmission electron microscope.
とを特徴とする請求項１〜７のいずれかに記載の微細炭
素繊維。8. The fine carbon fiber according to claim 1, wherein the fine carbon fiber is a vapor grown carbon fiber.
特徴とする請求項１〜８のいずれかに記載の微細炭素繊
維。9. The fine carbon fiber according to claim 1, wherein the boron element is contained in the carbon fiber.
部置換したことを特徴とする請求項１〜９のいずれかに
記載の微細炭素繊維。10. The fine carbon fiber according to claim 1, wherein the boron element is partially substituted with the carbon element of the carbon fiber.
造をなし、その中心軸が中空構造である外径２〜３００
ｎｍ、アスペクト比１０〜１５０００の微細炭素繊維を
熱処理することにより請求項１〜１０記載の微細炭素繊
維を製造する方法。11. An outer diameter of 2 to 300, wherein cylindrical carbon sheets overlap to form a multilayer structure, and the central axis thereof is a hollow structure.
The method for producing fine carbon fibers according to claim 1, wherein the fine carbon fibers having an aspect ratio of 10 to 15000 nm are subjected to a heat treatment.
であることを特徴とする請求項１１記載の微細炭素繊維
の製造方法。12. A heat treatment temperature of 2000 ° C. to 3500 ° C.
The method for producing fine carbon fibers according to claim 11, wherein:
造をなし、その中心軸が中空構造である外径２〜３００
ｎｍ、アスペクト比１０〜１５０００の微細炭素繊維と
ホウ素化合物とを混合して熱処理することを特徴とする
請求項１１または１２に記載の微細炭素繊維の製造方
法。13. An outer diameter of 2 to 300 wherein cylindrical carbon sheets overlap to form a multilayer structure, and the central axis thereof is a hollow structure.
The method for producing a fine carbon fiber according to claim 11 or 12, wherein a fine carbon fiber having an aspect ratio of 10 to 15000 nm and a boron compound are mixed and heat-treated.
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| JP2000381067A JP4010767B2 (en) | 2000-11-10 | 2000-11-10 | Fine carbon fiber aggregate |
| US09/986,438 US6565971B2 (en) | 2000-11-10 | 2001-11-08 | Fine carbon fiber and method for producing the same |
| US10/393,983 US6998171B2 (en) | 2000-11-10 | 2003-03-24 | Fine carbon fiber and method for producing the same |
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| JP2004096293A Division JP2004238791A (en) | 2004-03-29 | 2004-03-29 | Fine carbon fiber |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2003147641A (en) * | 2001-08-29 | 2003-05-21 | Gsi Creos Corp | Carbon fiber produced by vapor growth method, electrode material for battery, and method for producing the carbon fiber |
| JP2003342839A (en) * | 2002-05-23 | 2003-12-03 | Mitsubishi Heavy Ind Ltd | Carbon nano fibrin |
| JP2006051063A (en) * | 2004-08-10 | 2006-02-23 | Mizuno Technics Kk | Wooden bat |
| US7150840B2 (en) | 2002-08-29 | 2006-12-19 | Showa Denko K.K. | Graphite fine carbon fiber, and production method and use thereof |
| JP2008037679A (en) * | 2006-08-03 | 2008-02-21 | Nippon Hoso Kyokai <Nhk> | Method for producing fine carbon fiber material |
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| JP2003147641A (en) * | 2001-08-29 | 2003-05-21 | Gsi Creos Corp | Carbon fiber produced by vapor growth method, electrode material for battery, and method for producing the carbon fiber |
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