JPH0841730A - Production of high-thermal conductivity carbon fiber - Google Patents

Abstract

PURPOSE:To obtain the subject carbon fiber developing few fluffs, excellent in handleability, suitable for materials for space, aircraft and automotive brakes requiring thermal shock resistance and dimensional stability. CONSTITUTION:Optically anisotropic mesophase pitch is melted, fed via an inlet of diameter D1, contracted at an approach space with the profile from the inlet to circle-sectioned delivery hole 50-110mut m in capillary diameter D3 having an angle theta1, of 90-150 deg., and delivered via a spinning nozzle consisting of the capillary extended from the flat surface of diameter D2 situated at the terminal end of the approach space, thus forming fine pitch fibers each 5-11mum in diameter. The pitch fibers are then infusibilized and carbonized, and then graphitized in an inert gas atmosphere to obtain the objective high-thermal conductivity carbon fibers 4-8mum in single fiber diameter.

Description

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

【０００１】[0001]

【産業上の利用分野】本発明は平均繊維径が４〜８μｍ
の高熱伝導率炭素繊維の製造方法である。本発明で得ら
れた炭素繊維は耐熱衝撃性、寸法安定性を要求される宇
宙用材料、航空機用材料、自動車のブレーキ用材料等に
広く使用される。BACKGROUND OF THE INVENTION The present invention has an average fiber diameter of 4 to 8 μm.
Is a method for producing a high thermal conductivity carbon fiber. The carbon fiber obtained by the present invention is widely used for space materials, aircraft materials, automobile brake materials, etc., which are required to have thermal shock resistance and dimensional stability.

【０００２】[0002]

【従来の技術】現在、炭素繊維はポリアクリルニトリル
（ＰＡＮ）を原料としたＰＡＮ系炭素繊維とピッチを原
料としたピッチ系炭素繊維が製造されているが、現状で
は高性能炭素繊維として主にＰＡＮ系炭素繊維が用いら
れている。2. Description of the Related Art Currently, PAN-based carbon fibers made from polyacrylonitrile (PAN) and pitch-based carbon fibers made from pitch are manufactured as carbon fibers, but at present, they are mainly used as high-performance carbon fibers. PAN-based carbon fiber is used.

【０００３】しかしながら、市販されているＰＡＮ系炭
素繊維の熱伝導率は１００Ｗ／ｍＫよりも小さいため、
耐熱衝撃性、寸法安定性を要求される分野での使用は制
限される。However, since the thermal conductivity of commercially available PAN-based carbon fibers is less than 100 W / mK,
Use in fields requiring heat shock resistance and dimensional stability is limited.

【０００４】一方、メソフェースピッチを原料とするピ
ッチ系炭素繊維は、一般的にＰＡＮ系炭素繊維に比べ
て、高熱伝導率を示すと言われているが、市販のピッチ
系炭素繊維ではＡＭＯＣＯ社製ＴＨＯＲＮＥＬＰ―１２
０が高熱伝導率を示すが、７００Ｗ／ｍＫより小さいも
のである。On the other hand, pitch-based carbon fibers made from mesophase pitch are generally said to have higher thermal conductivity than PAN-based carbon fibers, but commercially available pitch-based carbon fibers are manufactured by AMOCO. Made THORNELP-12
0 shows high thermal conductivity, but it is smaller than 700 W / mK.

【０００５】特開平５―１６３６１９号公報には、３０
００℃以上で焼成することにより、黒鉛結晶子の層面方
向の広がりＬａが１０００Åより大きく、電気比抵抗が
１．１μΩｍより小さく、１１００Ｗ／ｍＫより大きい
熱伝導率をもつ炭素繊維の製造方法が開示されている。Japanese Unexamined Patent Publication No. 5-163619 discloses 30
Disclosed is a method for producing a carbon fiber having a thermal conductivity of less than 1100 W / mK and an electrical resistivity of less than 1.1 μΩm when the graphite crystallite has a spread La in the layer surface direction of more than 1000 Å by firing at a temperature of at least 00 ° C. Has been done.

【０００６】しかし１１００Ｗ／ｍＫより大きな熱伝導
率をもつピッチ系炭素繊維は極めて高弾性となるため繊
維糸条は剛直となり繊維のハンドリング時に繊維糸条が
折れたり、毛羽が多量に発生する等の問題がある。However, since pitch-based carbon fibers having a thermal conductivity of more than 1100 W / mK have extremely high elasticity, the fiber yarn becomes rigid and the fiber yarn is broken or a large amount of fluff occurs during the handling of the fiber. There's a problem.

【０００７】このため繊維のハンドリングが容易である
細径な高熱伝導率炭素繊維が求められるが、その製造方
法は報告されていない。[0007] For this reason, a thin carbon fiber having a high thermal conductivity, which enables easy handling of the fiber, is required, but a manufacturing method thereof has not been reported.

【０００８】特開平４―１６３３１９号公報には、ピッ
チ繊維を不融化し、酸素含有雰囲気中で延伸熱処理、延
伸予備炭化処理し、不活性ガス雰囲気下中で延伸しなが
ら炭化を行って熱伝導率、圧縮強度の高い炭素繊維の製
造方法が開示されている。In Japanese Patent Laid-Open No. 163319/1992, pitch fibers are infusibilized, subjected to a drawing heat treatment in an oxygen-containing atmosphere, a drawing pre-carbonization treatment, and a carbonization while drawing in an inert gas atmosphere to conduct heat. A method for producing a carbon fiber having a high rate and a high compression strength is disclosed.

【０００９】しかしながら、延伸処理を施してもＰＡＮ
系炭素繊維に匹敵するハンドリングが容易である繊維径
８μｍ未満である細径な高熱伝導率炭素繊維の製造方法
は報告されていない。However, even if the stretching treatment is applied, the PAN
There is no report of a method for producing a small diameter high thermal conductivity carbon fiber having a fiber diameter of less than 8 μm, which is easy to handle and is comparable to a carbon-based carbon fiber.

【００１０】またＪ．Ｍａｔｅｒ．Ｒｅｓ．，Ｖｏｌ．
５，Ｎｏ３，Ｐ５７０―５７７，Ｍａｒ １９９０の
「種々の温度で焼成したピッチ系炭素繊維の構造および
電気特性」の中では、ピッチ繊維の繊維径を変えて、不
融化、炭化を行い、種々の温度で焼成した結果、繊維径
の大きいピッチ繊維から得られた炭素繊維は、ピッチ繊
維中のメソフェースのドメインの平均サイズが大きくな
るため黒鉛化した際の黒鉛化性が繊維径の小さいものに
比べ高くなることを報告しており、従って細径な炭素繊
維から高熱伝導性の炭素繊維が得がたいことが推察され
る。In addition, J. Mater. Res. , Vol.
5, No3, P570-577, Mar 1990, "Structure and electrical characteristics of pitch-based carbon fiber fired at various temperatures", the fiber diameter of the pitch fiber is changed to infusibilize and carbonize, As a result of firing at a temperature, carbon fibers obtained from pitch fibers with a large fiber diameter have a larger average size of domains of mesophases in the pitch fibers, so the graphitization property when graphitized is smaller than that with a smaller fiber diameter. It has been reported that it becomes high, and therefore it is presumed that it is difficult to obtain a carbon fiber having high thermal conductivity from a carbon fiber having a small diameter.

【００１１】[0011]

【発明が解決しようとする課題】上記のように、従来の
技術から細径な炭素繊維から高熱伝導性の炭素繊維が得
がたいことが推察されるが、本発明者等は熱伝導性の高
い炭素繊維を作るために鋭意検討した結果、ある特定の
方法で製造された細径な炭素繊維が、従来の知見と異な
り繊維径の大きな炭素繊維に比べ黒鉛化性が高く、高熱
伝導な炭素繊維が得られることを見いだし、本発明に到
達した。As described above, it is presumed that it is difficult to obtain a carbon fiber having a high thermal conductivity from a carbon fiber having a small diameter, according to the conventional techniques. As a result of diligent studies to make fibers, a thin carbon fiber manufactured by a certain method has a higher graphitization property than a carbon fiber having a large fiber diameter, which is different from conventional findings, and a carbon fiber having high thermal conductivity is obtained. The inventors have found what is obtained and have reached the present invention.

【００１２】本発明の目的は繊維径が４〜８μｍの高熱
伝導率炭素繊維の製造方法を提供するものである。An object of the present invention is to provide a method for producing a high thermal conductivity carbon fiber having a fiber diameter of 4 to 8 μm.

【００１３】[0013]

【課題を解決するための手段】本発明は光学的異方性の
メソフェースピッチを溶融紡糸し、不融化、黒鉛化処理
して炭素繊維を製造する際に、メソフェースピッチを、 Ａ）導入孔から吐出孔に至る形状が９０〜１５０度の角
度のアプローチ部で縮流し、 Ｂ）アプローチ部終端で一旦平坦部とし、 Ｃ）平坦部に設けたキャピラリー径が５０〜１１０μｍ
である円形断面の吐出孔を有する紡糸ノズルを通過させ
て、紡糸を行い、繊維径５〜１１μｍの細径ピッチ繊維
を得、炭化した後、不活性ガス雰囲気下で黒鉛化するこ
とを特徴とする、繊維径が４〜８μｍの高熱伝導率炭素
繊維の製造方法である。Means for Solving the Problems In the present invention, when a mesophase pitch having optical anisotropy is melt-spun, infusibilized and graphitized to produce a carbon fiber, the mesophase pitch is introduced as follows. The shape from the hole to the discharge hole is contracted at the approach part with an angle of 90 to 150 degrees, and B) once made a flat part at the end of the approach part, and C) the diameter of the capillary provided at the flat part is 50 to 110 μm.
Is passed through a spinning nozzle having a circular cross-section discharge hole to obtain a fine pitch fiber having a fiber diameter of 5 to 11 μm, carbonized, and then graphitized in an inert gas atmosphere. The method for producing a high thermal conductivity carbon fiber having a fiber diameter of 4 to 8 μm.

【００１４】以下、本発明の内容を詳細に説明する。The contents of the present invention will be described in detail below.

【００１５】本発明の炭素繊維の出発原料であるピッチ
は、コールタール、コールタールピッチ等の石炭系ピッ
チ、石炭液化ピッチ、エチレンタールピッチ、流動接触
触媒分解残査から得られるデカントオイルピッチ等の石
油系ピッチ、あるいはナフタレン等から触媒などを用い
て作られる合成ピッチ等、各種ピッチを包含するもので
ある。The pitch which is the starting material of the carbon fiber of the present invention includes coal-based pitch such as coal tar and coal tar pitch, coal liquefied pitch, ethylene tar pitch, decant oil pitch obtained from fluid catalytic cracking residue. It includes various pitches such as petroleum pitch or synthetic pitch produced from naphthalene or the like using a catalyst or the like.

【００１６】本発明の光学的異方性のメソフェースピッ
チは、前記ピッチを従来公知の方法でメソフェースを発
生させたものである。The optically anisotropic mesophase pitch of the present invention is a pitch in which mesophases are generated by a conventionally known method.

【００１７】メソフェースピッチは、紡糸した際のピッ
チ繊維の配向性が高いものが望ましく、このためメソフ
ェース含有量は６０％以上、好ましくは８０％以上、さ
らに好ましくは９０％以上含有するものが望ましい。The mesophase pitch is preferably such that the pitch fibers are highly oriented when spun, and therefore the mesophase content is preferably 60% or more, preferably 80% or more, more preferably 90% or more. .

【００１８】なお、メソフェース含有量は６０％未満で
あると光学的異方性量が少ないため引張強度が低くなり
好ましくない。If the mesophase content is less than 60%, the amount of optical anisotropy is small and the tensile strength is low, which is not preferable.

【００１９】また本発明で用いるメソフェースピッチは
軟化点が２００〜４００℃、好ましくは２５０℃〜３５
０℃のものがよい。The mesophase pitch used in the present invention has a softening point of 200 to 400 ° C, preferably 250 to 35 ° C.
0 ° C is preferable.

【００２０】軟化点が２００℃未満のピッチはその調整
が困難であり、また軟化点が４００℃超のピッチを用い
ると紡糸温度を高温設定する必要が生じるため、安定し
た紡糸が行えなくなる。It is difficult to adjust a pitch having a softening point of less than 200 ° C., and if a pitch having a softening point of more than 400 ° C. is used, it is necessary to set the spinning temperature at a high temperature and stable spinning cannot be performed.

【００２１】ピッチ中に３μｍ以上の固形異物が存在す
ると紡糸時に糸切れが頻発することとなるので、得られ
たピッチは紡糸に先だって絶対濾過精度が３μｍ以下の
フィルター、あるいはこのフィルターと同等あるいはそ
れ以上の濾過精度をもつ濾過方法によりピッチ中の異物
を除去しておくことが望ましい。Since the presence of solid foreign matter of 3 μm or more in the pitch causes frequent yarn breakage during spinning, the obtained pitch has a filter with an absolute filtration accuracy of 3 μm or less prior to spinning, or the same as or equal to this filter. It is desirable to remove foreign matter in the pitch by a filtration method having the above filtration accuracy.

【００２２】高熱伝導率ピッチ系炭素繊維を製造するた
めの様々の検討の結果、黒鉛化性を高めることにより高
熱伝導率を得るには、ピッチ繊維状態における分子の繊
維軸方向への配向性がよいものを紡糸することが有効で
あることがわかった。As a result of various studies for producing a high thermal conductivity pitch-based carbon fiber, in order to obtain a high thermal conductivity by enhancing the graphitization property, the orientation of molecules in the pitch fiber state in the fiber axis direction is required. It has been found that spinning good ones is effective.

【００２３】本発明では前述のピッチからピッチ繊維を
紡糸する際に、図１に示すように導入孔から吐出孔に至
る形状（θ１）が９０〜１５０度の角度のアプローチ部
で縮流し、アプローチ終端で一旦平坦部（θ２）とし、
平坦部に設けた円形断面の吐出孔を通過させ、キャピラ
リー径（Ｄ３）が５０〜１１０μｍ、吐出口長さ（Ｌ
２）が０．０７〜０．１７ｍｍである紡糸ノズルを用い
て吐出口のピッチ粘度が１００〜１０００ｐｏｉｓｅ、
好ましくは２００〜８００ｐｏｉｓｅでさらに好ましく
は４００〜８００ｐｏｉｓｅで繊維径５〜１１μｍの細
径のピッチ繊維をつくることによって、繊維軸方向への
配向性の高いピッチ繊維が得られ、かつ高引張弾性率、
高引張強度をもつ高熱伝導率炭素繊維が得られる。In the present invention, when the pitch fiber is spun from the above-mentioned pitch, the shape (θ1) from the introduction hole to the discharge hole is contracted at the approach portion having an angle of 90 to 150 degrees as shown in FIG. At the end, once make a flat part (θ2),
It is passed through a circular cross-section discharge hole provided in the flat portion, the capillary diameter (D3) is 50 to 110 μm, and the discharge port length (L
2) is 0.07 to 0.17 mm, the spinning nozzle has a pitch viscosity of 100 to 1000 poise,
Pitch fibers having a high orientation in the fiber axis direction can be obtained by forming pitch fibers having a fine diameter of preferably 5 to 11 μm and more preferably 400 to 800 poise, and more preferably 400 to 800 poise, and a high tensile elastic modulus,
High thermal conductivity carbon fiber having high tensile strength is obtained.

【００２４】しかしながら炭素繊維においてラジアル成
分は軸方向の亀裂につながり、さらにこの亀裂は引張損
傷の生じやすい箇所になるため、従来のノズルでは高強
度化に限界があった。However, in the carbon fiber, the radial component leads to an axial crack, and this crack becomes a place where tensile damage is likely to occur. Therefore, the conventional nozzle has a limit to increase the strength.

【００２５】従来のアプローチ終端で平坦部を有しない
円形断面の吐出孔の紡糸ノズルを用いてピッチ繊維を
得、不融化、炭化、黒鉛化を行い得られた炭素繊維の横
方向の断面を走査電子顕微鏡で観察すると、繊維表層に
少なくとも１．５μｍから２．５μｍはラジアル構造を
持ち、繊維内部はランダムあるいはオニオン構造を持
ち、複数の構造をとり、ある程度の高強度を保持するこ
とができる。Pitch fibers were obtained using a spinning nozzle having a circular cross-section discharge hole at the end of the conventional approach, which was infusibilized, carbonized, and graphitized, and the cross section in the transverse direction of the obtained carbon fibers was scanned. When observed by an electron microscope, the fiber surface has a radial structure of at least 1.5 μm to 2.5 μm, and the inside of the fiber has a random or onion structure, and a plurality of structures can be formed to maintain a certain high strength.

【００２６】ところが、本発明で用いるノズル構造、す
なわち導入孔から吐出孔に至る形状が９０〜１５０度の
角度のアプローチ部で縮流し、アプローチ終端で一旦平
坦部としたのち、円形断面の吐出孔を持つ紡糸ノズルを
用いると繊維表層のラジアル成分が１．５μｍ以下、望
ましくは１．０μｍ以下になり、ラジアル成分が少なく
なる。However, the nozzle structure used in the present invention, that is, the shape from the introduction hole to the discharge hole is contracted at the approach portion having an angle of 90 to 150 degrees, and is once made flat at the end of the approach, and then the discharge hole having a circular cross section. When the spinning nozzle having the above is used, the radial component of the fiber surface layer becomes 1.5 μm or less, preferably 1.0 μm or less, and the radial component decreases.

【００２７】本発明に用いるノズルはこのように、表層
部のラジアル成分がより少なくなるため、さらに高引張
強度を保持することができる。Since the nozzle used in the present invention has a smaller radial component in the surface layer portion as described above, it is possible to maintain a higher tensile strength.

【００２８】アプローチ角度θ１は９０度未満では導入
口長さが長くなり不適切であり、１５０度超ではアプロ
ーチ終端で平坦部を設ける効果が得られ難くなる。If the approach angle θ1 is less than 90 degrees, the length of the inlet is too long, which is inappropriate, and if the approach angle θ1 exceeds 150 degrees, it is difficult to obtain the effect of providing a flat portion at the end of the approach.

【００２９】アプローチ角度θ１をこのように決定され
るので、また優れた引張強度を得るためには導入口長さ
Ｌ１は３〜１０ｍｍ、好ましくは４〜６ｍｍにすること
が好ましく、導入口径Ｄ１が０．５〜１０ｍｍ、好まし
くは１．２〜５ｍｍであり、導入口での滞留時間を１〜
４００秒、好ましくは４〜２００秒とすることが好まし
い。Since the approach angle θ1 is determined in this way, and in order to obtain excellent tensile strength, the inlet length L1 is preferably set to 3 to 10 mm, preferably 4 to 6 mm, and the inlet diameter D1 is set. 0.5 to 10 mm, preferably 1.2 to 5 mm, and the residence time at the inlet is 1 to
It is preferably 400 seconds, more preferably 4 to 200 seconds.

【００３０】導入口径が０．５ｍｍ未満あるいは１０ｍ
ｍ超、同様に滞留時間が１秒未満あるいは４００秒超で
は優れた強度の繊維を得ることができない。The inlet diameter is less than 0.5 mm or 10 m
If the residence time is more than m, and the residence time is less than 1 second or more than 400 seconds, fibers having excellent strength cannot be obtained.

【００３１】また、平坦部の径Ｄ２は導入口径Ｄ１の
０．８倍以下、吐出口径Ｄ３の１．５倍以上が望まし
く、このときに本発明の効果を最も得ることができる。
吐出孔の断面は引張強度の向上をもたらすためには円形
のものを用いたとき最も効果を発揮する。Further, the diameter D2 of the flat portion is preferably 0.8 times or less of the introduction port diameter D1 and 1.5 times or more of the discharge port diameter D3. At this time, the effect of the present invention can be most obtained.
The cross section of the discharge hole is most effective when a circular cross section is used in order to improve the tensile strength.

【００３２】また、キャピラリー径が５０μｍ未満で
は、キャピラリーの加工が非常に困難となったり、ノズ
ルの整備が煩雑となり、１１０μｍ超では、細径なピッ
チ繊維の紡糸が不安定となり好ましくない。If the capillary diameter is less than 50 μm, the processing of the capillary becomes very difficult and the maintenance of the nozzle becomes complicated, and if it exceeds 110 μm, the spinning of fine pitch fibers becomes unstable, which is not preferable.

【００３３】また吐出口長さ０．０７ｍｍ未満では安定
した紡糸が行えず、０．１７ｍｍ超では繊維表層部のラ
ジアル部分が増加することが推測され、そのために高強
度を保持できないことが考えられるため、キャピラリー
径と吐出口長さの比１．５〜２の範囲内が望ましい。Further, if the discharge port length is less than 0.07 mm, stable spinning cannot be performed, and if it exceeds 0.17 mm, the radial portion of the fiber surface layer portion is presumed to increase. Therefore, it is considered that high strength cannot be maintained. Therefore, it is desirable that the ratio of the capillary diameter to the discharge port length is within the range of 1.5 to 2.

【００３４】ピッチ粘度が１００ｐｏｉｓｅ未満では、
極度に粘度が低いため、断糸が増加し紡糸を行うことが
殆ど不可能となり、１０００ｐｏｉｓｅ超では、紡糸時
に糸切れが起きると他の糸もしくはノズル面に付着し、
紡糸が不安定となり好ましくない。When the pitch viscosity is less than 100 poise,
Since the viscosity is extremely low, the number of yarn breakage increases and it becomes almost impossible to perform spinning. If the yarn breakage occurs during spinning above 1000 poise, it will adhere to other yarn or the nozzle surface,
This is not preferable because spinning becomes unstable.

【００３５】また、４〜８μｍのハンドリング面で優位
な細径炭素繊維を得るためには、ピッチ繊維の繊維径
を、ピッチ繊維を不融化、炭化、黒鉛化することにより
繊維径の収縮が生じる分を予め考慮して、５〜１１μｍ
にしなければならない。In order to obtain a fine carbon fiber having an excellent handling property of 4 to 8 μm, the fiber diameter of the pitch fiber is reduced by infusibilizing, carbonizing or graphitizing the pitch fiber. 5-11 μm considering the minutes in advance
Must be.

【００３６】つぎにピッチ繊維は、酸化性ガス雰囲気
下、通常１００〜３５０℃、好ましくは１３０〜３２０
℃で、通常１０分〜１０時間、好ましくは１〜６時間、
不融化処理を行う。Next, the pitch fiber is usually 100 to 350 ° C., preferably 130 to 320 in an oxidizing gas atmosphere.
Usually at 10 ° C for 10 minutes to 10 hours, preferably 1 to 6 hours,
Perform infusibilization processing.

【００３７】酸化性ガスとしては酸素、空気あるいはこ
れらに二酸化窒素、塩素等を混合したガスが用いられ
る。不融化温度が１００度未満ではピッチの反応性が低
くなり、また３５０度超では過度の酸化が行われ、引張
強度が低下してしまう。As the oxidizing gas, oxygen, air, or a gas in which nitrogen dioxide, chlorine or the like is mixed is used. If the infusibilization temperature is less than 100 ° C., the reactivity of the pitch will be low, and if it exceeds 350 ° C., excessive oxidation will occur, resulting in a decrease in tensile strength.

【００３８】また不融化時間は１０分未満では反応が未
達となり、１０時間超では過度に不融化されてしまい好
ましくない。不融化処理した繊維は窒素、アルゴン等の
不活性ガス雰囲気下で炭化、黒鉛化処理を通常１秒〜１
０時間、好ましくは１０秒〜６時間行い、引張弾性率１
００ＧＰａ〜１０００ＧＰａ、引張強度２．０ＧＰａ〜
５．０ＧＰａの炭素繊維を得、黒鉛化することにより、
高引張弾性率、高引張強度をもち、且つ３０００℃以上
で黒鉛化すると１１００Ｗ／ｍＫより大きい熱伝導率を
有することを特徴とする繊維径が４〜８μｍのハンドリ
ング性に優れた細径ピッチ系高熱伝導率炭素繊維が得ら
れる。If the infusibilization time is less than 10 minutes, the reaction will not be achieved, and if it exceeds 10 hours, the infusibilization will be excessively unfavorable. The infusibilized fiber is generally carbonized and graphitized in an inert gas atmosphere such as nitrogen or argon for 1 second to 1 second.
0 hours, preferably 10 seconds to 6 hours, tensile modulus 1
00GPa-1000GPa, tensile strength 2.0GPa-
By obtaining 5.0 GPa carbon fiber and graphitizing it,
A fine pitch system having a high tensile elastic modulus and a high tensile strength, and having a thermal conductivity of more than 1100 W / mK when graphitized at 3000 ° C. or more and having a fiber diameter of 4 to 8 μm and excellent in handleability. High thermal conductivity carbon fibers are obtained.

【００３９】黒鉛化処理した繊維の、黒鉛化の進行度合
いは、広角Ｘ線回折から求めた積層厚みＬｃ００２、結
晶子の大きさＬａ１１０、層間隔ｄ００２で評価した。The degree of progress of graphitization of the graphitized fiber was evaluated by the layer thickness Lc002, the crystallite size La110, and the layer spacing d002 obtained from wide-angle X-ray diffraction.

【００４０】積層厚みＬｃ００２は炭素結晶中の００２
面の積層の厚さを、Ｌａ１１０は結晶子の大きさを、層
間隔ｄ００２は結晶の００２面の層間隔を示し、Ｌｃ０
０２は５０〜５００Å、Ｌａ１１０は１００〜１０００
Å以上、ｄ００２は３．３５２〜３．４５０Åの値を示
す。The layer thickness Lc002 is 002 in the carbon crystal.
La110 is the thickness of the layer stack, La110 is the size of the crystallite, layer spacing d002 is the layer spacing of the 002 plane of the crystal, and Lc0
02 is 50 to 500Å, La110 is 100 to 1000
Above Å, d002 indicates a value of 3.352 to 3.450Å.

【００４１】Ｌｃ００２、Ｌａ１１０が大きいほど、ま
たｄ００２が小さいほど黒鉛化性が高いと判断でき、格
子欠陥による伝導電子の散乱が抑えられて高熱伝導率を
示す。It can be judged that the larger the Lc002 and La110 are, and the smaller the d002 is, the higher the graphitization property is, and scattering of conduction electrons due to lattice defects is suppressed and high thermal conductivity is exhibited.

【００４２】積層厚みＬｃ００２、結晶子の大きさＬａ
１１０、層間隔ｄ００２は繊維を粉末状にしたのち、標
準シリコンと混合して試料とする粉末法を用い、００２
面、１１０面の回折線から学振法「人造黒鉛の格子定数
および結晶子の大きさ測定法」により求めた。Lamination thickness Lc002, crystallite size La
110, the layer interval d002 is 002 by using a powder method in which fibers are made into a powder and then mixed with standard silicon to obtain a sample.
Plane, 110 diffraction planes were determined by the Gakshin method “method for measuring lattice constant of artificial graphite and size of crystallite”.

【００４３】また熱伝導率は、炭素繊維を直径１０ｍ
ｍ、厚さ３ｍｍ〜６ｍｍの円柱状一方向炭素繊維強化プ
ラスチックにし、理学電気（株）製レーザーフラッシュ
法熱定数測定装置ＰＳ―７型を用いて、比熱および熱拡
散率を測定し、次式により算出した。The thermal conductivity of carbon fiber is 10 m.
m, a thickness of 3 mm to 6 mm, and a columnar unidirectional carbon fiber reinforced plastic, and the specific heat and thermal diffusivity were measured using a laser flash method thermal constant measuring device PS-7 type manufactured by Rigaku Denki Co., Ltd. It was calculated by

【００４４】[0044]

【数１】λ＝Ｃｐ×α×ρ／Ｖｆ## EQU1 ## λ = Cp × α × ρ / Vf

【００４５】ここでλは炭素繊維の熱伝導率、αは炭素
繊維の熱拡散率、Ｃｐは一方向炭素繊維強化プラスチッ
クの絶対比熱、ρは密度、Ｖｆは一方向炭素繊維強化プ
ラスチック中に含まれる炭素繊維の体積分率である。Here, λ is the thermal conductivity of the carbon fiber, α is the thermal diffusivity of the carbon fiber, Cp is the absolute specific heat of the unidirectional carbon fiber reinforced plastic, ρ is the density, and Vf is included in the unidirectional carbon fiber reinforced plastic. This is the volume fraction of carbon fiber that is used.

【００４６】マトリックス樹脂の熱伝導率は、炭素繊維
の熱伝導率に対して無視できるほど小さいので炭素繊維
の熱伝導率はλで求められる。なお、測定は室温（２５
℃）で行った。Since the thermal conductivity of the matrix resin is negligibly smaller than that of the carbon fiber, the thermal conductivity of the carbon fiber can be calculated by λ. In addition, the measurement is at room temperature (25
C.).

【００４７】以下、さらに本発明を明確にするために、
実施例、比較例を用いて説明する。Hereinafter, in order to further clarify the present invention,
An example and a comparative example will be described.

【００４８】[0048]

【実施例】【Example】

【００４９】[0049]

【実施例１】原料としてコールタールピッチを用い、触
媒存在下で直接水素化を行い、この水素化ピッチを減圧
化５００℃で熱処理したのち、低沸点成分を除きメソフ
ェースピッチを得た。Example 1 Using coal tar pitch as a raw material, direct hydrogenation was carried out in the presence of a catalyst, and the hydrogenated pitch was heat-treated at a reduced pressure of 500 ° C. to obtain mesophase pitch after removing low boiling point components.

【００５０】このピッチは軟化点３０４℃、トルエン不
溶分８０重量％でメソフェース含有量が９４％であっ
た。このメソフェースピッチを用いて、図１に示すよう
な導入孔から吐出孔に至る形状が１２０度の角度のアプ
ローチ部で縮流し、アプローチ終端で一旦平坦部とし、
キャピラリー径０．１０ｍｍ、吐出口長さ０．１５ｍ
ｍ、平坦部長さ０．８ｍｍのノズルを用い、吐出口のピ
ッチ粘度が４５０ポイズになるように紡糸し、繊維径１
０μｍのピッチ繊維を得た。This pitch had a softening point of 304 ° C., a toluene insoluble content of 80% by weight, and a mesophase content of 94%. By using this mesoface pitch, the shape from the introduction hole to the discharge hole as shown in FIG. 1 is contracted at the approach part with an angle of 120 degrees, and once flattened at the approach end.
Capillary diameter 0.10 mm, discharge port length 0.15 m
m, the flat portion length was 0.8 mm, and was spun so that the pitch viscosity of the discharge port was 450 poise, and the fiber diameter was 1
0 μm pitch fibers were obtained.

【００５１】このピッチ繊維を、空気に二酸化窒素ガス
を５体積％、酸素ガスを１０体積％添加した酸化雰囲気
下で、１５０℃から３１０℃まで１℃／ｍｉｎで昇温し
不融化繊維を得た。この不融化繊維を３９０℃まで昇温
し、５０ｍｉｎ炭化し、炭化繊維を得た。The pitch fiber was heated from 150 ° C. to 310 ° C. at 1 ° C./min in an oxidizing atmosphere in which 5% by volume of nitrogen dioxide gas and 10% by volume of oxygen gas were added to the air to obtain an infusible fiber. It was The infusible fiber was heated to 390 ° C. and carbonized for 50 minutes to obtain a carbonized fiber.

【００５２】つぎにこの炭化繊維を３２００℃の温度
で、３時間黒鉛化処理を行い炭素繊維を得た。Next, this carbonized fiber was graphitized at a temperature of 3200 ° C. for 3 hours to obtain a carbon fiber.

【００５３】この炭素繊維は、繊維径７．４μｍで、引
張弾性率９００ＧＰａ、引張強度３．３ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が４５０Å、Ｌａ１１０が９
１０Å、ｄ００２が３．３６４Å、熱伝導率１１８０Ｗ
／ｍＫであり毛羽の発生は極めて少なかった。This carbon fiber has a fiber diameter of 7.4 μm, a tensile elastic modulus of 900 GPa, a tensile strength of 3.3 GPa, an X-ray structural parameter of Lc002 = 450Å, and La110 = 9.
10Å, d002 is 3.364Å, thermal conductivity is 1180W
/ MK, and the occurrence of fluff was extremely small.

【００５４】[0054]

【実施例２】実施例１のピッチを用いて図１に示すよう
な導入角１３５度、キャピラリー径０．０９ｍｍ、吐出
口長さ０．１４ｍｍのノズルを用い、吐出口のピッチ粘
度が６００ポイズになるように紡糸し、繊維径９．５μ
ｍのピッチ繊維を得た。Example 2 Using the pitch of Example 1, a nozzle having an introduction angle of 135 degrees, a capillary diameter of 0.09 mm, and an ejection port length of 0.14 mm as shown in FIG. 1 was used, and the ejection port pitch viscosity was 600 poise. The fiber diameter is 9.5μ
m pitch fibers were obtained.

【００５５】このピッチ繊維を用いて実施例１と同じ条
件で不融化、炭化、黒鉛化を行い炭素繊維を得た。Using this pitch fiber, infusibilization, carbonization and graphitization were carried out under the same conditions as in Example 1 to obtain a carbon fiber.

【００５６】この炭素繊維は、繊維径６．８μｍで、引
張弾性率９８０ＧＰａ、引張強度４．０ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が４８０Å、Ｌａ１１０が９
７０Å、ｄ００２が３．３５９Å、熱伝導率１２３０Ｗ
／ｍＫであり毛羽の発生は極めて少なかった。This carbon fiber has a fiber diameter of 6.8 μm, a tensile elastic modulus of 980 GPa, a tensile strength of 4.0 GPa, an X-ray structural parameter of Lc002 of 480Å, and La110 of 9.
70Å, d002 is 3.359Å, thermal conductivity is 1230W
/ MK, and the occurrence of fluff was extremely small.

【００５７】[0057]

【比較例１】実施例１のピッチを用いて図２に示すよう
な導入角１２０度、キャピラリー径０．１０ｍｍ、吐出
口長さ０．１５ｍｍのノズルを用い、吐出口のピッチ粘
度が４５０ポイズになるように紡糸し、繊維径１０μｍ
のピッチ繊維を得た。Comparative Example 1 Using the pitch of Example 1, a nozzle having an inlet angle of 120 degrees, a capillary diameter of 0.10 mm, and a discharge port length of 0.15 mm as shown in FIG. 2 was used, and the pitch viscosity of the discharge port was 450 poise. And the fiber diameter is 10 μm
The pitch fiber of was obtained.

【００５８】このピッチ繊維を用いて実施例１と同じ条
件で不融化、炭化、黒鉛化を行い炭素繊維を得た。Using this pitch fiber, infusibilization, carbonization and graphitization were carried out under the same conditions as in Example 1 to obtain a carbon fiber.

【００５９】この炭素繊維は、繊維径７．４μｍで、引
張弾性率９００ＧＰａ、引張強度２．８ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が４２０Å、Ｌａ１１０が７
６０Å、ｄ００２が３．３６５Å、熱伝導率１０７０Ｗ
／ｍＫであり毛羽の発生は多かった。This carbon fiber has a fiber diameter of 7.4 μm, a tensile elastic modulus of 900 GPa, a tensile strength of 2.8 GPa, an X-ray structural parameter of Lc002 of 420Å and La110 of 7
60Å, d002 is 3.365Å, thermal conductivity is 1070W
/ MK, and the occurrence of fluff was large.

【００６０】[0060]

【比較例２】実施例１のピッチを用いて図２に示すよう
な導入角１２０度、キャピラリー径０．１０ｍｍ、吐出
口長さ０．１５ｍｍのノズルを用い、吐出口のピッチ粘
度が６００ポイズになるように紡糸し、繊維径１３μｍ
のピッチ繊維を得た。Comparative Example 2 Using the pitch of Example 1, a nozzle having an inlet angle of 120 degrees, a capillary diameter of 0.10 mm, and a discharge port length of 0.15 mm as shown in FIG. 2 was used, and the pitch viscosity of the discharge port was 600 poise. And the fiber diameter is 13 μm
The pitch fiber of was obtained.

【００６１】このピッチ繊維を用いて実施例１と同じ条
件で不融化、炭化、黒鉛化を行い炭素繊維を得た。Using this pitch fiber, infusibilization, carbonization and graphitization were carried out under the same conditions as in Example 1 to obtain a carbon fiber.

【００６２】この炭素繊維は、繊維径９．０μｍで、引
張弾性率９００ＧＰａ、引張強度２．５ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が３５０Å、Ｌａ１１０が５
９０Å、ｄ００２が３．３７０Å、熱伝導率６００Ｗ／
ｍＫであり毛羽の発生は多かった。This carbon fiber has a fiber diameter of 9.0 μm, a tensile elastic modulus of 900 GPa, a tensile strength of 2.5 GPa, and an X-ray structural parameter of Lc002 of 350Å and La110 of 5.
90Å, d002 is 3.370Å, thermal conductivity is 600W /
Since it was mK, fuzz was generated frequently.

【００６３】[0063]

【比較例３】実施例１のピッチを用いて図２に示すよう
な導入角１２０度、キャピラリー径０．１０ｍｍ、吐出
口長さ０．１５ｍｍのノズルを用い、吐出口のピッチ粘
度が７００ポイズになるように紡糸し、繊維径１３μｍ
のピッチ繊維を得た。Comparative Example 3 Using the pitch of Example 1, a nozzle having an inlet angle of 120 degrees, a capillary diameter of 0.10 mm, and a discharge port length of 0.15 mm as shown in FIG. 2 was used, and the pitch viscosity of the discharge port was 700 poise. And the fiber diameter is 13 μm
The pitch fiber of was obtained.

【００６４】このピッチ繊維を用いて実施例１と同じ条
件で不融化、炭化、黒鉛化を行い炭素繊維を得た。Using this pitch fiber, infusibilization, carbonization and graphitization were carried out under the same conditions as in Example 1 to obtain a carbon fiber.

【００６５】この炭素繊維は、繊維径９．３μｍで、引
張弾性率９００ＧＰａ、引張強度２．３ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が３６０Å、Ｌａ１１０が６
５０Å、ｄ００２が３．３６９Å、熱伝導率７００Ｗ／
ｍＫであり毛羽の発生は多かった。This carbon fiber has a fiber diameter of 9.3 μm, a tensile elastic modulus of 900 GPa, a tensile strength of 2.3 GPa, an X-ray structural parameter of Lc002 of 360Å, and La110 of 6
50Å, d002 is 3.369Å, thermal conductivity is 700W /
Since it was mK, fuzz was generated frequently.

【００６６】[0066]

【比較例４】実施例１のピッチを用いて図２に示すよう
な導入角１２０度、キャピラリー径０．１２ｍｍ、吐出
口長さ０．２０ｍｍのノズルを用い、吐出口のピッチ粘
度が６００ポイズになるように紡糸し、繊維径１０μｍ
のピッチ繊維を得た。[Comparative Example 4] Using the pitch of Example 1, a nozzle having an inlet angle of 120 degrees, a capillary diameter of 0.12 mm, and a discharge port length of 0.20 mm as shown in FIG. 2 was used, and the discharge port pitch viscosity was 600 poise. And the fiber diameter is 10 μm
The pitch fiber of was obtained.

【００６７】このピッチ繊維を用いて実施例１と同じ条
件で不融化、炭化、黒鉛化を行い炭素繊維を得た。Using this pitch fiber, infusibilization, carbonization and graphitization were carried out under the same conditions as in Example 1 to obtain a carbon fiber.

【００６８】この炭素繊維は、繊維径７．３μｍで、引
張弾性率９００ＧＰａ、引張強度２．７ＧＰａ、Ｘ線構
造パラメータがＬｃ００２が２９０Å、Ｌａ１１０が４
９０Å、ｄ００２が３．３７９Å、熱伝導率５３０Ｗ／
ｍＫであり毛羽の発生は多かった。This carbon fiber has a fiber diameter of 7.3 μm, a tensile elastic modulus of 900 GPa, a tensile strength of 2.7 GPa, an X-ray structural parameter of Lc002 of 290Å and La110 of 4
90Å, d002 is 3.379Å, thermal conductivity is 530W /
Since it was mK, fuzz was generated frequently.

【００６９】[0069]

【発明の効果】本発明の炭素繊維は、工業的に実施適応
が容易な技術で、同一条件で炭化または黒鉛化された従
来の炭素繊維にくらべて極めて大きな熱伝導率を示し、
毛羽の発生が極めて少なく、また繊維糸条が折れる問題
が少ない、すなわちハンドリング性に優れた細径炭素繊
維を製造することができ、耐熱衝撃性、寸法安定性を要
求される宇宙用材料、航空機用材料、自動車用材料等の
分野での利用に適した炭素繊維を提供することが可能と
なる。INDUSTRIAL APPLICABILITY The carbon fiber of the present invention is a technology which is industrially easy to apply and shows, and exhibits extremely large thermal conductivity as compared with the conventional carbon fiber carbonized or graphitized under the same conditions.
Extremely few fluffs and less problem of fiber yarn breakage, that is, it is possible to manufacture small diameter carbon fibers with excellent handling properties, and space materials and aircraft that require thermal shock resistance and dimensional stability. It is possible to provide a carbon fiber suitable for use in the fields of automotive materials, automotive materials, and the like.

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

【図１】本発明に用いる紡糸ノズルの一部断面概略図を
示す。FIG. 1 shows a partial cross-sectional schematic view of a spinning nozzle used in the present invention.

【図２】比較例に用いる従来の紡糸ノズルの一部断面概
略図を示す。FIG. 2 shows a partial cross-sectional schematic view of a conventional spinning nozzle used in a comparative example.

【符号の説明】[Explanation of symbols]

Ｄ１ 導入口径 Ｄ２ 平坦部直径 Ｄ３ キャピラリー径 Ｌ１ 導入口長さ Ｌ２ 吐出口長さ θ１ アプローチ部角度 θ２ 平坦部角度 D1 introduction port diameter D2 flat part diameter D3 capillary diameter L1 introduction port length L2 discharge port length θ1 approach part angle θ2 flat part angle

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 光学的異方性のメソフェースピッチを溶
融紡糸し、不融化、炭化、黒鉛化処理して炭素繊維を製
造する際に、メソフェースピッチを、 Ａ）導入孔から吐出孔に至る形状が９０〜１５０度の角
度のアプローチ部で縮流し、 Ｂ）アプローチ部終端で一旦平坦部とし、 Ｃ）平坦部に設けたキャピラリー径が５０〜１１０μｍ
である円形断面の吐出孔を有する紡糸ノズルを通過させ
て、紡糸を行い、繊維径５〜１１μｍの細径ピッチ繊維
を得、不融化、炭化した後、不活性ガス雰囲気下で黒鉛
化することを特徴とする、繊維径が４〜８μｍの高熱伝
導率炭素繊維の製造方法。1. When a carbon fiber is produced by melt spinning an optically anisotropic mesophase pitch and subjecting it to infusibilization, carbonization and graphitization, the mesophase pitch is introduced from the A) introduction hole to a discharge hole. The entire shape is contracted at the approach part with an angle of 90 to 150 degrees, and B) the flat part is once made at the end of the approach part, and C) the diameter of the capillary provided in the flat part is 50 to 110 μm.
And passing through a spinning nozzle having a circular cross-section discharge hole to obtain a fine pitch fiber having a fiber diameter of 5 to 11 μm, infusibilized and carbonized, and then graphitized in an inert gas atmosphere. A method for producing a high thermal conductivity carbon fiber having a fiber diameter of 4 to 8 μm.