JPS60199921A - Vapor-phase production of carbon fiber - Google Patents

Abstract

PURPOSE:Electricity is allowed to flow from both ends of a carbon rod covered with carbon particles around the surface to heat the rod over sublimation temperature of carbon to allow carbon fibers to precipitate on the carbon rod on its surface, thus giving carbon fibers with high thermal and electrical conductivities. CONSTITUTION:Carbon rod 1 is covered with carbon particles, preferably of 100-10 mesh particle sizes (e.g., from coke or bitumen) and electricity is applied to both ends of the carbon rod 1 to heat it over the sublimation temperature of carbon, preferably higher than 3,400 deg.C to precipitate carbon fibers on the surface of the carbon rod 1. The temperature gradient from the surface of the electrode to the inside of the carbon particles is preferably 20-100 deg.C/cm.

Description

【発明の詳細な説明】 本発明は新規な方法による気相法炭素繊維の製造法に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing vapor grown carbon fiber by a novel method.

炭素繊維の製造法は有機繊維を炭化する方法、ベンゼン
等を熱分解して炭素繊維を析出させる方法がある。前者
の方法は大量生産に向いているが電気伝導性や熱伝導性
はよくないので、これらの特性が要求される繊維として
は不適である。そしてこの繊維は黒鉛化処理してもこれ
らの特性はあまり上らない。Carbon fibers can be produced by carbonizing organic fibers or by thermally decomposing benzene or the like to precipitate carbon fibers. Although the former method is suitable for mass production, it does not have good electrical conductivity or thermal conductivity, so it is not suitable for fibers that require these properties. Even if this fiber is graphitized, these properties do not improve much.

後者の方法によって得られる炭素繊維は黒鉛化処理すれ
ば熱伝導度、電気伝導度が向上するが、それには特別の
処理を必要とする。Carbon fibers obtained by the latter method can be graphitized to improve their thermal conductivity and electrical conductivity, but this requires special treatment.

本発明は従来と全く異なった方法による炭素繊維の製造
法に関し、その特徴は周囲を炭素粒で覆った炭素棒全実
質的にその昇華温度以上に加熱し、昇華した炭素を炭素
棒の表面に析出させることにある。本発明によって得ら
れる炭素繊維（黒鉛化している）は上記気相法炭素繊維
以上の熱伝導度、電気伝導度を示す。The present invention relates to a method for manufacturing carbon fibers that is completely different from conventional methods, and its feature is that the entire carbon rod whose periphery is covered with carbon grains is heated to substantially above its sublimation temperature, and the sublimated carbon is applied to the surface of the carbon rod. The purpose is to precipitate it. The carbon fiber (graphitized) obtained by the present invention exhibits higher thermal conductivity and electrical conductivity than the above-mentioned vapor grown carbon fiber.

以下、図面を参考に本発明全具体的に説明する。Hereinafter, the present invention will be fully explained in detail with reference to the drawings.

第１図は本発明の方法に用いられる装置の１例を示す断
面図である。１は炭素棒（黒鉛棒を含む）で、その周囲
は炭素粒２で覆われている。炭素粒は具体的にはコーク
ス、無煙炭などであり、これらは繰ｐ返し使用されるに
つれて黒鉛化が進むが、その場合は粒度配合等を変えて
保温性全調整することにより、使用することができる。FIG. 1 is a sectional view showing an example of an apparatus used in the method of the present invention. 1 is a carbon rod (including a graphite rod), and its periphery is covered with carbon grains 2. Carbon grains are specifically coke, anthracite, etc. As these are used repeatedly, they become graphitized, but in that case, it is possible to use them by changing the particle size composition etc. and adjusting the heat retention property completely. can.

炭素粒の大きさは保温性に関係し、本発明においては重
要な因子である。実験によれば本発明方法によって炭素
繊維を炭素棒の表面に析出させるには、炭素棒の表面か
ら炭素粒に向けての温度勾配が重要な作用をなし、それ
が適当な範囲にあることが必要であることがわかった。The size of carbon particles is related to heat retention and is an important factor in the present invention. Experiments have shown that in order to deposit carbon fibers on the surface of a carbon rod by the method of the present invention, the temperature gradient from the surface of the carbon rod toward the carbon grains plays an important role, and that it is within an appropriate range. It turned out to be necessary.

温度勾配が大き過ぎると繊維の成長が見られず、繊維が
非常に短かいものとなる。また勾配が小さい、即ち保温
性がよすざると析出物が粒状となる。また保温性をよく
するため、炭素粒全組かくするとガスの噴出が激しく運
転が困難である。If the temperature gradient is too large, fiber growth will not be observed and the fibers will be very short. In addition, if the gradient is small, that is, if the heat retention is poor, the precipitate becomes granular. In addition, if all the carbon grains are hidden in order to improve heat retention, gas will be ejected violently and operation will be difficult.

実験によれば、電極表面からその近傍の炭素粒内の温度
勾配は２０℃／ｃｍ〜１００℃／ｃｍの範囲が望ましい
ことがわかった。According to experiments, it has been found that the temperature gradient within the carbon grains from the electrode surface to the vicinity thereof is preferably in the range of 20° C./cm to 100° C./cm.

炭素粒の保温性は主としてその粒度配合によって決まる
。上記の温度勾配にするには炭素粒は１００〜１０メツ
シユの範囲、その中で通常のコークスの場合、１００メ
ツシユ〜１０メツシーの範囲、黒鉛化が進んだコークス
では１００メツシユ〜２０メツシユの範囲のものを用い
ればよい。The heat retention properties of carbon grains are mainly determined by their particle size composition. To achieve the above temperature gradient, the carbon particles must be in the range of 100 to 10 meshes, within which the carbon particles must be in the range of 100 to 10 meshes for normal coke, and the range of 100 to 20 meshes for highly graphitized coke. Just use something.

炭素棒はその両端の案内電極４から電源５によシ通電し
て加熱する。ｌは耐火レンガで構成された炉でちる。炭
素棒の加熱温度は炭素が実質的に昇華する温度以上にす
る必要がある。炭素が昇華する温度は常圧で約３００℃
、昇華熱は１７０ｋｃａｌ／ｍｏｌと言われるが、この
温度以下でも徐々に昇華を始めるので、この昇華が炭素
繊維をある程度析出させるに足る量であればよく、本発
明において実質的にとはこのような昇華を意味する。The carbon rod is heated by being energized by a power source 5 from guide electrodes 4 at both ends thereof. l is a furnace made of refractory bricks. The heating temperature of the carbon rod needs to be higher than the temperature at which carbon substantially sublimates. The temperature at which carbon sublimates is approximately 300°C at normal pressure.
The heat of sublimation is said to be 170 kcal/mol, but since sublimation begins gradually even below this temperature, it is sufficient if the amount of sublimation is sufficient to precipitate carbon fibers to some extent, and in the present invention, this is essentially what is meant by sublimation. It means sublimation.

具体的には３３００℃以上、好ましくは３４００℃以上
である。炭素棒に通電加熱する方式では通常、中心部分
が最も温度が高いが、上記の温度はこの中心部の温度で
ある。パイロメーター等で３３００℃以上の温度の直接
測定はむずかしいので少し離れた３０００℃ぐらいの温
度シー／での温度分布から目的とする所の温度を推定し
た。Specifically, the temperature is 3300°C or higher, preferably 3400°C or higher. In a method in which a carbon rod is heated with electricity, the temperature is usually highest at the center, and the above temperature is the temperature at this center. Since it is difficult to directly measure temperatures above 3,300°C with a pyrometer, etc., we estimated the temperature at the target location from the temperature distribution at a temperature point a little further away at about 3,000°C.

繊維の取シ出し方法は上部のコークス層を少しづつ吸引
排除していくと、炭素発熱体の光面付近に生えた炭素繊
維が見えてくるので、ヘラ、コテ等で取シ出す。コーク
ス粒の間を縫う様に成長するので、長い繊維は得がたい
。１〜２ｃｍのものが殆んどである。付着しているコー
クス粒を選別除去して繊維を得る。To remove the fibers, the upper coke layer is removed by suction little by little, and the carbon fibers grown near the light surface of the carbon heating element become visible, and then removed using a spatula, trowel, etc. It is difficult to obtain long fibers because they grow between coke grains. Most of them are 1 to 2 cm long. The attached coke grains are sorted out and fibers are obtained.

本発明において、炭素棒１の構造全第２図のように他端
を封じた中空５とし、そのＩ端６よシアルボン等の不活
性ガスを流して炭素の昇華を促進させることは有効な方
法である。炭素棒は多孔質なので多少加圧してガスを中
空部に導入すればその表面よシ噴出する。中空のものは
加熱物の重量が少なくてすむので、それだけエネルギー
効率は良い。In the present invention, it is an effective method to form a hollow 5 with the other end sealed as shown in FIG. 2, and to flow an inert gas such as sialbone through the I end 6 to promote sublimation of carbon. It is. Since the carbon rod is porous, if some pressure is applied and gas is introduced into the hollow part, it will eject from the surface. Hollow ones require less weight to heat, so they are more energy efficient.

本発明方法によって得られる炭素繊維は第３図に示すよ
うに前記した気相熱分解によって生成する年輪状構造の
ものと違って軸方向に伸びた帯の集束体のような構造で
ある。長さは１〜５ｃｒｎ、太さは２００〜３００μｍ
に達する。図は走査型電子顕微鏡による繊維の形状写真
でちる（倍率４００）。As shown in FIG. 3, the carbon fibers obtained by the method of the present invention have a structure like a bundle of bands extending in the axial direction, unlike the annual ring-like structure produced by the above-described vapor phase pyrolysis. The length is 1~5crn, the thickness is 200~300μm
reach. The figure is a photograph of the shape of the fibers taken with a scanning electron microscope (400 magnification).

この繊維は既に３０００℃以上の熱処理を受けたもので
ある為に、結晶は良く発達しておシ、電気土祇杭も１０
０μΩｍ台と極端に低いので層間化金物用原料等として
も有用である。Since this fiber has already been heat treated at over 3000℃, the crystals are well developed and the electric clay grade is 10%.
Since it has an extremely low value of 0 μΩm, it is also useful as a raw material for interlayer metal parts.

実施例 使用した炭素棒の長さは４ｍ、直径１５ｃｆｎである。Example The length of the carbon rod used was 4 m and the diameter was 15 cfn.

コークス粒の大きさは５０〜７０メツシユのものを使用
した。通電の条件は電流３０〜６０ｋＡ（直流）、電圧
１００〜１５０■、時間１０Ｈｒ、推定の温度は中心部
で３４００℃、発熱体表面で３３００℃、温度勾配は発
熱体表面より外で５０℃／σと推定される。繊維は炭素
棒よりコークス粒の隙間に伸びていた。炭素棒の周辺の
コークス粒を注意深く剥ぎとり、繊維を炭素棒に付着さ
せたまま残した。繊維の長さは平均１〜２ｃＩｎ、最高
で４〜５ｃｒｎであり太さは１００〜３００μでちった
。収量は５００ｇであった。この繊維の走査型電子顕微
鏡の写真（４００倍）を第３図に示す。The size of the coke grains used was 50 to 70 mesh. The conditions for energization are: current 30-60kA (DC), voltage 100-150cm, time 10Hr, estimated temperature is 3400℃ at the center, 3300℃ at the surface of the heating element, and the temperature gradient is 50℃/50℃ outside the surface of the heating element. It is estimated that σ. The fibers extended more into the gaps between the coke grains than the carbon rods. The coke grains around the carbon rod were carefully stripped away, leaving the fibers attached to the carbon rod. The average fiber length was 1 to 2 cIn, the maximum was 4 to 5 crn, and the thickness was 100 to 300 microns. Yield was 500g. A scanning electron microscope photograph (400x magnification) of this fiber is shown in FIG.

この繊維は結晶性がよく、黒鉛の層間化合物をつくるの
に適する。This fiber has good crystallinity and is suitable for making graphite intercalation compounds.

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

第１図は本発明方法に用いられる装置の１例を示す断面
図、第２図はその中の１部の断面図である。第３図は繊
維の顕微鏡写真である。 １・・・炭素棒、２・・・コークス粒、５・・・中空部
。 出願人　昭和電工株式会社 第２図 第３図 手　続　補　止　書（自発） 昭和５９年５月２日 許庁長官　若杉和犬　殿 事件の表示 昭和５９年特許願第５１２３８号 発明の名称 気相法炭素Ｈ＆雑の製造法 補正をする者 事件との関係　特許出願人 住所　東京都港区芝大門−丁目１３番９号名称　（２０
０）　昭和電工株式会社　−７−１゜昭和電工株式会ン
１内 ５、補正の対象 明細書の「発明の詳細な説明」の欄。 ６、補正の内容 明細書第４頁、第５行目の「約３００℃」を「約３４０
０℃」に訂正する。FIG. 1 is a sectional view showing one example of an apparatus used in the method of the present invention, and FIG. 2 is a sectional view of a part thereof. FIG. 3 is a microscopic photograph of the fiber. 1... Carbon rod, 2... Coke grains, 5... Hollow part. Applicant: Showa Denko Co., Ltd. Figure 2, Figure 3 Proceedings Supplement (voluntary) May 2, 1980 Commissioner of the License Agency Kazuinu Wakasugi Indication of the case 1982 Patent Application No. 51238 Name of the invention Relationship with the Case of Person Who Amends the Manufacturing Method of Carbon H & Miscellaneous Patent Applicant Address 13-9 Shiba Daimon-chome, Minato-ku, Tokyo Name (20
0) Showa Denko Co., Ltd. -7-1゜Showa Denko Co., Ltd. 1-5, "Detailed Description of the Invention" column of the specification to be amended. 6. Change "approximately 300 degrees Celsius" to "approximately 340 degrees Celsius" on page 4, line 5 of the specification of contents of the amendment.
Corrected to 0℃.

Claims (2)

【特許請求の範囲】[Claims] （１）炭素棒の周囲を炭素粒で覆い、炭素棒の両端から
通電して炭素棒を炭素が実質的に昇華する温度以上に加
熱して、炭素棒の表面上に炭素繊維を析出させることを
特徴とする気相法炭素繊維の製造法。(1) Precipitating carbon fibers on the surface of the carbon rod by covering the periphery of the carbon rod with carbon particles and applying electricity from both ends of the carbon rod to heat the carbon rod to a temperature higher than that at which carbon substantially sublimates. A method for producing vapor-grown carbon fiber characterized by: （２）炭素粒の大きさを１００メツシユ〜１０メツシユ
とする特許請求の範囲第１項記載の気相法炭素繊維の製
造法。(2) The method for producing vapor-grown carbon fibers according to claim 1, wherein the carbon particles have a size of 100 meshes to 10 meshes.