JPH0370012B2 - - Google Patents
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- JPH0370012B2 JPH0370012B2 JP59125048A JP12504884A JPH0370012B2 JP H0370012 B2 JPH0370012 B2 JP H0370012B2 JP 59125048 A JP59125048 A JP 59125048A JP 12504884 A JP12504884 A JP 12504884A JP H0370012 B2 JPH0370012 B2 JP H0370012B2
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- 239000011295 pitch Substances 0.000 claims description 75
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 56
- 239000004917 carbon fiber Substances 0.000 claims description 56
- 239000000835 fiber Substances 0.000 claims description 54
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 31
- 241000446313 Lamella Species 0.000 claims description 15
- 230000003287 optical effect Effects 0.000 claims description 12
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- 238000002844 melting Methods 0.000 description 16
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- 238000010438 heat treatment Methods 0.000 description 12
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 8
- 229920002239 polyacrylonitrile Polymers 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
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- 238000005245 sintering Methods 0.000 description 4
- 241000234282 Allium Species 0.000 description 3
- 235000002732 Allium cepa var. cepa Nutrition 0.000 description 3
- 239000003245 coal Substances 0.000 description 3
- 239000011294 coal tar pitch Substances 0.000 description 3
- 230000000875 corresponding effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000003208 petroleum Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000011337 anisotropic pitch Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 239000000295 fuel oil Substances 0.000 description 2
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- 239000003921 oil Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical compound [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009657 carbon fiber testing Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
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- 238000001816 cooling Methods 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
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- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000003027 oil sand Substances 0.000 description 1
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- 230000000171 quenching effect Effects 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 239000012783 reinforcing fiber Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000011269 tar Substances 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000005292 vacuum distillation Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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- Inorganic Fibers (AREA)
Description
［産業上の利用分野］
本発明は新規でかつ特異な内部構造を有する高
強度高モジユラスのピツチ系炭素繊維に関するも
のである。
［従来技術］
炭素繊維は、当初レーヨンを原料として製造さ
れたが、その特性、経済性の点で、現在はポリア
クリロニトリル（PAN）繊維を原料とするPAN
系炭素繊維と、石炭又は石油系のピツチ類を原料
とするピツチ系炭素繊維によつて占められてい
る。なかでも、ピツチを原料として高性能グレー
ドの炭素繊維を製造する技術は、経済性にすぐれ
ているため注目を集めており、例えば光学異方性
ピツチを溶融紡糸して得たピツチ繊維を不融化・
焼成した炭素繊維は、それまでのピツチ系炭素繊
維に比して高強度高モジユラスのものが得られて
いる。
また、ピツチ系炭素繊維の内部断面構造を制御
することにより、更に高い物性が発現し得るとい
うことも見出されている（Fuel、1980、60、
839、特開昭59−53717号等）。
すなわち、ピツチ系炭素繊維の断面構造として
は、ランダム、ラジアル、オニオン構造又はその
複合構造が存在し、ラジアル構造はクラツクを生
じやすくマクロ欠陥による物性低下が生じるため
好ましくないとされている。また、ピツチ系炭素
繊維におけるランダム構造は実質はラメラのサイ
ズが小さいラジアル構造であり、強度的には好ま
しい構造であるが、ピツチ調製及び紡糸の高ドラ
フト又は急冷化が十分でないとクラツクが生じや
すく製造条件が限定されてくる。
オニオン構造は、現象的には紡糸ピツチの粘性
変化温度によりも高い温度まで昇温された後紡糸
することによつて得られるが（特開昭59−53717
号公報参照）、通常の光学異方性ピツチにおいて
は、この粘性変化温度が350℃以上の高温である
ため紡糸の安定性が悪く、得られる繊維もボイド
を含んだものになりやすいため、ボイドレスのオ
ニオン構造の繊維は溶融紡糸では安定に得ること
がむつかしい。
このため、従来のピツチ系炭素繊維はPAN系
炭素繊維に匹敵する引張り強度を実現することは
困難とされている。
［発明の目的］
本発明の目的は、従来のピツチ系炭素繊維とは
全く異つた断面構造を有し、従来のピツチ系炭素
繊維に比べて飛躍的に改善された物性を有してお
り、しかも製造上の困難が少ない新規なピツチ系
炭素繊維を提供することにある。
［発明の構成］
本発明者らは、強度、モジユラスなどの性能に
おいてPAN系炭素繊維に匹敵するか、もしくは
より優れたピツチ系炭素繊維を開発するために鋭
意研究を行つた結果、光学異方性の紡糸用ピツチ
を溶融紡糸する際、特定の工夫を加えることによ
り、ピツチ分子の配列を意のままに制御できるこ
とを究明し、従来のラジアル、ランダム又はオニ
オン構造とは全く異なつた特異な微細構造を有し
かつPAN系炭素繊維に匹敵するすぐれた性能を
示す、新規なピツチ系炭素繊維が得られることを
見出し、この知見に基づいて本発明を完成するに
至つた。
すなわち、本発明の新規な炭素繊維は、その断
面の少なくとも30％以上の部分に合計３個以上の
リフ状ラメラ配列を呈する部分を有し、かつ引張
り強度が300Kg／mm2以上であることによつて特徴
づけられるピツチ系炭素繊維である。
ここでいうリーフ状ラメラ配列とは、炭素繊維
の長さ方向とほぼ垂直な方向に切断した断面を走
査型電子顕微鏡によつて観察することによつて識
別ができるもので、基本的には第１図〜第７図に
示すごとく、中心軸から対称に15〜90゜の角度で
多数のラメラが両側に伸びた木の葉（葉脈）状の
ラメラ配列を指し、従来全く知られていなかつた
新規な構造である。
ここで、第１図〜第４図は本発明のピツチ系炭
素繊維の断面構造を模式的に示す見取図であり、
第５図〜第７図は該繊維の断面構造を示す走査型
電子顕微鏡写真である。
第１図及び第６図の繊維ではリーフ状ラメラが
４つ組合わさつており、第２図〜第４図及び第５
図のものは３つのリーフ状ラメラが組合わさつて
おり、また第７図は６つのリーフ状ラメラを有す
るものである。
各リーフ状ラメラの中心軸は直線又は曲線であ
つてもよく、各リーフ状ラメラの大きさは特に制
限されない。一般に繊維断面に内在するリーフ状
ラメラの数が多い場合はそれぞれのリーフ状ラメ
ラは相対的に小さくなり、数が少ない場合はそれ
ぞれのリーフ状ラメラは大きくなる。また、リー
フ状ラメラが、繊維断面積に占める割面（面積比
率）は少くとも30％が好ましく、50％以上が特に
好ましい。
すなわち、本発明の炭素繊維には、多くの場
合、リーフ状ラメラ配列を有するリーフ状ラメラ
構造（以下、リーフ構造という）の部分(A)とその
周りの構造が不明確な部分(B)とが存在するが、Ａ
の面積／（Ａ＋Ｂ）の面積の割合が少くとも30％
以上、特に50％以上有することが好ましい。
本発明に係る炭素繊維の断面形状（外形）は、
第１図、第２図、及び第６図のような円形、第４
図及び第５図のようなトライローバル形を含むマ
ルチローバル形、第７図のような六角形等を含む
各種のマルチアングル形等任意の形状をとること
ができる。
繊維径は円形断面に換算して５〜50μｍの範囲
にするのが好ましく、繊維長は任意に選択でき
る。
前記のような特殊なリーフ状ラメラ配列を有す
る本発明の炭素繊維は、少なくとも300Kg／mm2の
引張り強度を備えており、殆んどの場合、400
Kg／mm2以上の引張り強度と15T／mm2以上のモジユ
ラスとを有するPAN系炭素繊維に匹敵する物性
を示す。特に、後述の実施例に示す如く、製造条
件によつては、500Kg／mm2を超える引張り強度と
25T／mm2を超えるモジユラスとを示す場合もあ
り、従来のピツチ系炭素繊維からは全く予想でき
ないようなすぐれた物性を有する。
本発明の炭素繊維のもつ、このようなすぐれた
物性は、該繊維の断面構造が前述のようなリーフ
状ラメラ配列をとつているため、不融化・焼成段
階のクラツクの発生が防止され、構造の緻密化が
可能となり高強度・高モジユラスが発現したもの
と考えられる。
このような優れた諸性能を有する本発明の炭素
繊維は、光学異方性領域を50％以上有する紡糸用
ピツチを溶融した後、特定の形状を有する紡糸孔
から溶融紡糸し、これを不融化・焼成することに
よつて容易にかつ安定に製造することができる。
次に、この製造方法について詳細に説明する。
本発明の炭素繊維を製造するための原料として
は、光学異方性領域を50％以上、好ましくは80％
以上有するピツチを用いる。光学異方性領域の割
合が50％未満の光学異方性ピツチは、可紡性が悪
く、均質かつ安定な物質のものが得られないばか
りでなく、得られる炭素繊維の物性も低いものと
なる。
紡糸用ピツチの融点は250℃〜350℃が好まし
い。また紡糸用ピツチのキノリン可溶部の割合は
30重量％以上が好ましく、特に30〜80重量％が好
適である。これらのパラメーターは原料ピツチに
よつて異なるが通常は相関があり、光学異方性量
が多い程融点が高く、キノリン可溶部の割合は低
くなる。本発明において好適に用いられる紡糸用
ピツチ領域の割合（以下、光学異方性量という）
が多い程よい。このようなピツチは系が均質であ
り、可紡性にすぐれている。
このような紡糸用ピツチの原料としては、例え
ばコールタール、コールタールピツチ、石炭液化
物のような石炭系重質油や、石油の常圧残留油、
減圧蒸留及びこれらの残油の熱処理によつて副生
するタールやピツチ、オイルサンド、ビチユーメ
ンのような石油系重質油を精製したものを用い、
これを熱処理、溶剤抽出、水素化処理等を組合せ
て処理することによつて得られる。
本発明の炭素繊維を製造するには、前述の如き
紡糸用ピツチを溶融紡糸する際の紡糸口金の紡糸
孔（ノズル）形状が特に重要である。すなわち、
前述の如き紡糸用ピツチの溶融物を次式（）
（）を同時に満足する少くとも２本のスリツト
状部を有する特殊な紡糸孔を通じて溶融紡糸す
る。
かかる紡糸孔としては、各スリツト部における
中心線距離をLnとし、それに対応するぬれぶち
幅をWnとしたとき、（但しｎ＝２〜10の整数）
Lnの少なくとも３個が、
Ln＜1.0（mm） ……（）
1.5Ln／Wn20 ……（）
を同時に満足するものを使用する。
かかる紡糸孔としては、互いに交差した直線状
又は曲線状の複数のスリツトからなる紡糸孔、互
いに独立した３個以上のスリツトを組合せて１つ
の紡糸孔単位としたもの等があげられ、例えば第
８図〜第１１図に例示する紡糸孔が使用される。
なお、複数のスリツトが交差した第８図〜第１
１図の紡糸孔では交差部の内接円を除いた部分の
各スリツトの中心線の長さL1，L2，L3，L4，L5，
L6が中心線距離であり、それぞれのスリツトに
おける最大幅（角中心線と直交する方向の最大距
離）W1，W2，W3，W4，W5，W6が各中心線距
離に対応するぬれぶち幅となる。
本発明の炭素繊維を形成するには、前記Ln及
びWnの少なくとも１組が前記式（）（）を
同時に満足する必要があるが、その全部又は殆ん
どが前記式（）（）を同時に満足するのが好
ましい。
本発明者らの研究によれば、交差部を有する複
数のスリツトからなる紡糸孔の場合には、各スリ
ツトのLnが1.5Ln／Wn10を満足するものが、
好ましいリーフ構造を形成し易く、特に好適であ
ることが確認された。
これに対し、従来のピツチ繊維の溶融紡糸に使
用されている円形紡糸孔を有する紡糸口金を用い
た場合や、Ln／Wnが前記範囲外の異形紡糸孔
（例えば正三角形、正多角形等の紡糸孔）を有す
る紡糸口金を用いた場合には、炭素繊維の断面が
リーフ状ラメラ配列となり得ず、ラジアル構造又
は構造が不明瞭なランダム構造となつてしまう。
溶融紡糸における紡糸温度は、融点より40〜
100℃高い温度を採用する。本発明でいう融点と
は、DSCで測定される値であり、測定方法は後
述するが、紡糸用ピツチの融解開始温度である。
本発明において、紡糸温度は紡糸口金温度であ
り、この温度は繊維断面形状（外形）及び内部の
リーフ状構造の生成に大きく影響する。紡糸温度
が高いと繊維断面は紡糸孔形状からの変化が大き
く円形断面に近づく。更に紡糸温度を高くすると
可紡性が低下し、得られる糸もボイドを含んだも
のとなる。一方、紡糸口金温度が低い程得られる
繊維断面形状（外形）は紡糸孔形状に近くなる。
更に低くするとドラフト率が低下し繊維径を細く
することが困難となる。リーフ構造の中心軸は、
紡糸口金温度が高い程、直線からの変形が大きく
なるため、リーフ構造そのものも変形し判別しに
くくなるが、リーフ構造であることにかわりはな
く、繊維は高度の物性を発現する。具体例をあげ
るとＹ字形紡糸孔を有する紡糸口金を用いて紡糸
する場合、紡糸口金温度が低いと繊維断面形状
（外形）はトライローバル形となり、温度を上げ
るにつれてトライアングルから円形へ連続的に変
化する。リーフ構造は、紡糸口金温度が低いと、
中心軸も直線状で構造も明瞭であるが、温度を上
げるにつれて中心軸が繊維断面形状（外形）の変
化と対応し変形、構造もやや不明瞭になる。
前述のごとき紡糸孔から光学異方性ピツチを紡
糸すると、何故リーフ状構造を生ずるかは未だ充
分解明されておらず、今後の詳細な検討を待たね
ばならないが、およそ次の様に考えられる。
光学異方性を有するピツチは板状分子と推定さ
れ、このような板状分子は紡糸口金のノズル（紡
糸孔）内の等速度線に対し直角に配列し易い。円
形ノズル内の等速度線は円状でありこれに分子が
直角に配列するため、得られるピツチ繊維の断面
内でピツチ分子はラジアル状に配列する。このた
め不融化・焼成段階で、分子面間隔の収縮時に応
力歪みが生じ易くクラツクを生じる。
これに対し前述の中心線を有するスリツト部を
有するノズル内の等速度線はＵ字状となり、これ
に分子が直角に配列するとピツチ分子は繊維断面
内でリーフ状ラメラを構成するように配列する。
この配列は、不融化・焼成段階での分子面間隔の
収縮時に応力歪みを吸収し易い配列であるため、
分子は緻密に充填される等の理由により、クラツ
ク発生がなくなり、著しくすぐれた繊維物性が発
現すると考えられる。
このようなスリツト状の紡糸孔から紡出された
繊維は、ドラフト率30以上、好ましくは50以上で
引き取ることが好適である。ここでドラフト率と
は次式で定義される値であり、この値が大きいこ
とは紡糸時の変形速度が大きく、他の条件が同一
の場合はドラフト率が大きい程、急冷効果が大と
なる。
ドラフト率＝紡糸引取速度／紡糸口金からの吐出線速度
ドラフト率30以上、特に50以上で引き取ると、
引続く不融化・焼成処理により、好適な物性を発
現しやすいので好ましい。
紡糸引取速度は、前述の紡糸条件では1000ｍ／
分以上の速度でもきわめて円滑に紡糸することが
できるが、通常300〜2000ｍ／分の範囲が好まし
く用いられる。
前記のような特殊な紡糸口金を採用して得られ
たピツチ繊維は、次いで、酸素の存在下に不融化
処理される。
この不融化処理工程は生産性および繊維物性を
左右する重要な工程で、できるだけ短時間で実施
することが好ましい。このため、不融化温度、昇
温速度、雰囲気ガス等を紡糸ピツチ繊維に対し適
宜選択する必要があるが、本発明のピツチ繊維
は、高融点の光学異方性ピツチを用いていること
及び、繊維断面形状が非円形（異形）であるとき
は、単位断面積当りの表面積が大きいこと等によ
り、通常の円形断面から紡糸された従来のピツチ
繊維よりも処理時間を短縮することが可能であ
る。
このように不融化処理した繊維は次に不活性ガ
ス中において通常1000〜1500℃の温度で焼成する
ことにより本発明に係る３個以上のリーフ構造を
有する炭素繊維を得ることができる。このものを
そのまま使用してもよいが、さらに約3000℃程度
までに加熱して黒鉛化させてから使用するこもで
きる。
［発明の効果］
前述の如き本発明のピツチ系炭素繊維は、その
断面積構造がリーフ状ラメラ配列を有するために
クラツクが防止され、さらに不融化・焼成段階で
の収縮が円滑におこなわれるため、引張り強度、
モジユラスが飛躍的に増大し、PAN系炭素繊維
の物性を凌駕するものとなる。また、繊維断面形
状が非円形の場合は表面積が増加するため接着性
が改良され、複合材の補強繊維として好適に用い
られる。
各指標の測定法
次に本発明における紡糸用ピツチ及び繊維特性
を表わす各指標の測定法について説明する。
(a) 紡糸用ピツチの融点
パーキンエルマー社製DSC−1D型を用い、
アルミニウム製セル（内径５ｍ／ｍ）に100メ
ツシユ以下に粉砕したピツチ微粉末10mgを入
れ、上から押えた後、窒素雰囲気中、昇温速度
10℃／分で400℃近くまで昇温しつつ測定し、
DSCのチヤートにおける融点を示す吸熱ピー
クをもつて紡糸用ピツチの融点とする。
(b) 紡糸用ピツチの光学異方性量
反射型偏光顕微鏡を用いて紡糸ピツチの偏光
顕微鏡写真を任意に５枚とり、画像解析処理装
置を用いて、等方性領域の面積分率（％）を出
し、このものの平均値を光学異方性量とする。
(c) 炭素繊維の物性
炭素繊維の繊維系（単糸径）、引張強度、伸
度、モジユラスはJIS Ｒ−7601「炭素繊維試験
方法」に従つて測定する。なお繊維径の測定
は、円形断面繊維についてはレーザーによる測
定を行い、非円形断面繊維については走査型電
子顕微鏡写真よりｎ＝15の断面積の平均値を算
出する。なお、実施例等においては繊維径を相
当する断面積を有する円に換算したときの直径
で表示した。
(d) リーフ状ラメラ配列の分率
炭素繊維断面の走査型電子顕微鏡写真より、
断面積あたりのリーフ状ラメラ配列部分の面積
比率で表わす。
［実施例］
以下、実験例をあげて本発明をさらに詳細に説
明するが、本発明はこれらの実施例によつて何ら
限定されるものではない。
なお、後述する各実施例及び比較例において使
用した紡糸口金の紡糸孔は、次の一覧表に示す通
りである。なお、表中のθは放射状スリツトの各
中心線のなす角をラジアンで表示したものであ
る。
[Industrial Application Field] The present invention relates to a high-strength, high-modulus pitch-based carbon fiber having a novel and unique internal structure. [Prior art] Carbon fiber was initially manufactured using rayon as a raw material, but due to its characteristics and economic efficiency, it is now manufactured using polyacrylonitrile (PAN) fiber as a raw material.
and pitch-based carbon fibers made from coal or petroleum-based pitches. Among these, the technology to produce high-performance grade carbon fiber using pitch as a raw material is attracting attention because of its excellent economic efficiency.・
The fired carbon fibers have higher strength and higher modulus than conventional pitch-based carbon fibers. It has also been discovered that even higher physical properties can be developed by controlling the internal cross-sectional structure of pitch-based carbon fibers (Fuel, 1980, 60 ,
839, Japanese Patent Application Publication No. 59-53717, etc.). That is, the cross-sectional structure of pitch-based carbon fibers includes random, radial, onion structures, or composite structures thereof, and it is said that radial structures are unfavorable because they tend to cause cracks and deteriorate physical properties due to macro defects. In addition, the random structure of pitch-based carbon fibers is actually a radial structure with small lamella sizes, which is a preferable structure in terms of strength, but cracks are likely to occur if the pitch preparation and spinning draft or rapid cooling is not sufficient. Manufacturing conditions are limited. The onion structure can be obtained by spinning after heating the spinning pitch to a temperature higher than the viscosity change temperature (Japanese Patent Laid-Open No. 59-53717
In the case of ordinary optically anisotropic pitches, the viscosity change temperature is as high as 350°C or higher, resulting in poor spinning stability and the resulting fibers tend to contain voids. It is difficult to stably obtain fibers with onion structure by melt spinning. For this reason, it is difficult for conventional pitch-based carbon fibers to achieve tensile strength comparable to PAN-based carbon fibers. [Object of the Invention] The object of the present invention is to provide a carbon fiber that has a cross-sectional structure completely different from that of conventional pitch-based carbon fibers and has dramatically improved physical properties compared to conventional pitch-based carbon fibers. Moreover, it is an object of the present invention to provide a new pitch-based carbon fiber that is less difficult to manufacture. [Structure of the Invention] As a result of intensive research to develop pitch-based carbon fibers that are comparable to or better than PAN-based carbon fibers in terms of performance such as strength and modulus, the inventors have discovered that optical anisotropy has been achieved. When melt spinning pitches for spinning, it was discovered that by adding a specific device, the arrangement of pitches molecules could be controlled at will. The inventors have discovered that a new pitch-based carbon fiber can be obtained that has a structure and exhibits excellent performance comparable to that of PAN-based carbon fiber, and based on this knowledge, they have completed the present invention. That is, the novel carbon fiber of the present invention has a portion exhibiting a total of three or more rift-like lamellar arrays in at least 30% of its cross section, and has a tensile strength of 300 Kg/mm 2 or more. It is a pitch-based carbon fiber that is characterized by: The leaf-like lamellar arrangement referred to here can be identified by observing a cross-section cut in a direction almost perpendicular to the length direction of carbon fibers using a scanning electron microscope. As shown in Figures 1 to 7, it refers to a leaf-like lamellar arrangement in which many lamellae extend on both sides at angles of 15 to 90 degrees symmetrically from the central axis, and is a novel and previously unknown arrangement. It is a structure. Here, FIGS. 1 to 4 are sketches schematically showing the cross-sectional structure of the pitch-based carbon fiber of the present invention,
FIGS. 5 to 7 are scanning electron micrographs showing the cross-sectional structure of the fiber. In the fibers shown in Figures 1 and 6, four leaf-like lamellae are combined, and in the fibers shown in Figures 2-4 and 5.
The one in the figure has three leaf-like lamellae combined, and the one in FIG. 7 has six leaf-like lamellae. The central axis of each leaf-like lamella may be a straight line or a curve, and the size of each leaf-like lamella is not particularly limited. Generally, when the number of leaf-like lamellae inherent in a fiber cross section is large, each leaf-like lamella becomes relatively small, and when the number is small, each leaf-like lamella becomes large. Furthermore, the split surface (area ratio) of the leaf-like lamella in the fiber cross-sectional area is preferably at least 30%, particularly preferably 50% or more. That is, in many cases, the carbon fiber of the present invention has a part (A) with a leaf-like lamella structure having a leaf-like lamella arrangement (hereinafter referred to as leaf structure) and a part (B) where the structure around it is unclear. exists, but A
The ratio of area / (A + B) area is at least 30%
It is particularly preferable to have 50% or more. The cross-sectional shape (outer shape) of the carbon fiber according to the present invention is
Circular as shown in Figures 1, 2, and 6,
It can take any shape, such as a multilobal shape including a trilobal shape as shown in FIGS. and 5, and various multi-angle shapes including a hexagonal shape as shown in FIG. The fiber diameter is preferably in the range of 5 to 50 μm in terms of circular cross section, and the fiber length can be selected arbitrarily. The carbon fibers of the present invention with the above-mentioned special leaf-like lamella arrangement have a tensile strength of at least 300 Kg/ mm2 , and in most cases 400 Kg/mm2.
It exhibits physical properties comparable to PAN-based carbon fibers, having a tensile strength of Kg/mm 2 or more and a modulus of 15 T/mm 2 or more. In particular, as shown in the examples below, depending on the manufacturing conditions, the tensile strength can exceed 500 kg/ mm2 .
In some cases, it exhibits a modulus exceeding 25T/mm 2 , and has excellent physical properties that cannot be expected from conventional pitch-based carbon fibers. These excellent physical properties of the carbon fibers of the present invention are due to the fact that the cross-sectional structure of the fibers has a leaf-like lamellar arrangement as described above, which prevents the occurrence of cracks during the infusibility and firing stages, and improves the structure. This is thought to be due to the fact that it became possible to densify the material, resulting in high strength and high modulus. The carbon fiber of the present invention, which has such excellent performance, is obtained by melting a spinning pitch having an optical anisotropy region of 50% or more, then melt-spinning it through a spinning hole with a specific shape, and making it infusible. - Can be easily and stably produced by firing. Next, this manufacturing method will be explained in detail. The raw material for producing the carbon fiber of the present invention has an optical anisotropy area of 50% or more, preferably 80%.
Use a pitch having the following properties. Optically anisotropic pitches with an optically anisotropic region ratio of less than 50% have poor spinnability, making it impossible to obtain homogeneous and stable materials, and the resulting carbon fibers also have poor physical properties. Become. The melting point of the spinning pitch is preferably 250°C to 350°C. Also, the proportion of quinoline soluble part in the spinning pitch is
The content is preferably 30% by weight or more, particularly preferably 30 to 80% by weight. Although these parameters vary depending on the raw material pitch, they are usually correlated; the greater the amount of optical anisotropy, the higher the melting point, and the lower the proportion of quinoline soluble portion. Ratio of spinning pitch area suitably used in the present invention (hereinafter referred to as optical anisotropy amount)
The more, the better. Such pitches have a homogeneous system and are excellent in spinnability. Raw materials for such spinning pitches include, for example, coal tar, coal tar pitch, coal-based heavy oils such as coal liquefied products, atmospheric residual oil of petroleum,
Using refined petroleum-based heavy oils such as tar, pitch, oil sand, and bitumen, which are by-produced through vacuum distillation and heat treatment of these residual oils,
This can be obtained by a combination of heat treatment, solvent extraction, hydrogenation treatment, etc. In producing the carbon fibers of the present invention, the shape of the spinning hole (nozzle) of the spinneret used when melt spinning the spinning pitch as described above is particularly important. That is,
The melt of the spinning pitch described above is expressed by the following formula ()
Melt spinning is carried out through a special spinning hole having at least two slit-shaped parts that simultaneously satisfy (). As for such a spinning hole, when the center line distance at each slit part is Ln and the corresponding wetted edge width is Wn, (however, n = an integer from 2 to 10).
Use at least three Ln that simultaneously satisfy Ln<1.0 (mm)...() 1.5Ln/Wn20...(). Examples of such spinning holes include a spinning hole consisting of a plurality of linear or curved slits that intersect with each other, and a spinning hole unit made by combining three or more independent slits, and the like. The spinning holes illustrated in FIGS. 11 to 11 are used. In addition, in Figures 8 to 1, where multiple slits intersect,
In the spinning hole shown in Figure 1, the lengths of the center lines of each slit excluding the inscribed circle at the intersection are L 1 , L 2 , L 3 , L 4 , L 5 ,
L 6 is the center line distance, and the maximum width of each slit (the maximum distance in the direction orthogonal to the corner center line) W 1 , W 2 , W 3 , W 4 , W 5 , W 6 is the center line distance. This is the corresponding wet width. In order to form the carbon fiber of the present invention, at least one set of Ln and Wn needs to simultaneously satisfy the above formulas () and (), but all or most of them simultaneously satisfy the above formulas () and (). It is preferable to be satisfied. According to the research conducted by the present inventors, in the case of a spinning hole consisting of a plurality of slits having intersections, the Ln of each slit satisfies 1.5Ln/Wn10.
It was confirmed that it is easy to form a preferable leaf structure and is particularly suitable. On the other hand, when a spinneret with a circular spinning hole, which is used in the conventional melt spinning of pitch fibers, is used, or when a spinneret with an irregularly shaped spinning hole with Ln/Wn outside the above range (for example, a regular triangle, a regular polygon, etc.) is used. When a spinneret having spinning holes (spinning holes) is used, the cross-section of the carbon fibers cannot have a leaf-like lamellar arrangement, but instead has a radial structure or a random structure with an unclear structure. The spinning temperature in melt spinning is 40~40°F below the melting point.
Adopts a temperature 100℃ higher. The melting point in the present invention is a value measured by DSC, and the measuring method will be described later, and is the melting start temperature of the spinning pitch.
In the present invention, the spinning temperature is the spinneret temperature, and this temperature greatly influences the fiber cross-sectional shape (outer shape) and the formation of the internal leaf-like structure. When the spinning temperature is high, the fiber cross section changes significantly from the spinning hole shape and approaches a circular cross section. Furthermore, when the spinning temperature is increased, the spinnability decreases, and the resulting yarn also contains voids. On the other hand, the lower the spinneret temperature, the closer the obtained fiber cross-sectional shape (outer shape) becomes to the spinning hole shape.
If it is lowered further, the draft rate decreases and it becomes difficult to reduce the fiber diameter. The central axis of the leaf structure is
The higher the spinneret temperature, the greater the deformation from the straight line, so the leaf structure itself deforms and becomes difficult to distinguish, but it is still a leaf structure and the fibers exhibit high physical properties. To give a specific example, when spinning using a spinneret with a Y-shaped spinning hole, when the spinneret temperature is low, the fiber cross-sectional shape (outer shape) becomes a trilobal shape, and as the temperature increases, it changes continuously from a triangle to a circle. do. The leaf structure is formed when the spinneret temperature is low.
The central axis is also linear and the structure is clear, but as the temperature increases, the central axis corresponds to changes in the cross-sectional shape (outer shape) of the fibers, deforms, and the structure becomes somewhat unclear. The reason why a leaf-like structure is produced when optically anisotropic pitch is spun from the above-mentioned spinning holes is not fully understood yet, and will have to be investigated in detail in the future, but it is thought to be approximately as follows. Pits having optical anisotropy are presumed to be plate-shaped molecules, and such plate-shaped molecules tend to be arranged at right angles to a constant velocity line in the nozzle (spinning hole) of a spinneret. Since the uniform velocity line in the circular nozzle is circular and the molecules are arranged at right angles to it, the pitch molecules are arranged radially within the cross section of the resulting pitch fiber. For this reason, during the infusibility and sintering stages, stress distortion is likely to occur when the molecular spacing contracts, resulting in cracks. On the other hand, the constant velocity line in a nozzle with a slit section having the aforementioned centerline is U-shaped, and when molecules are arranged at right angles to this line, the pitch molecules are arranged to form leaf-like lamellae within the fiber cross section. .
This arrangement is one that easily absorbs stress strain when the molecular plane spacing shrinks during the infusibility and sintering stages.
It is thought that because the molecules are densely packed, cracks do not occur and extremely excellent fiber properties are developed. The fibers spun from such slit-shaped spinning holes are preferably taken at a draft rate of 30 or more, preferably 50 or more. Here, the draft rate is a value defined by the following formula, and a large value means a high deformation speed during spinning, and if other conditions are the same, the larger the draft rate, the greater the quenching effect. . Draft rate = spinning take-off speed / linear velocity of discharge from the spinneret If the draft rate is over 30, especially over 50,
This is preferable because suitable physical properties can be easily developed through the subsequent infusibility and sintering treatment. The spinning take-off speed is 1000 m/min under the above spinning conditions.
Although spinning can be carried out very smoothly even at a speed of 300 to 2000 m/min, the preferred range is usually 300 to 2000 m/min. The pitch fiber obtained by employing the above-mentioned special spinneret is then treated to be infusible in the presence of oxygen. This infusibility treatment step is an important step that affects productivity and fiber properties, and is preferably carried out in as short a time as possible. Therefore, it is necessary to appropriately select the infusibility temperature, heating rate, atmospheric gas, etc. for the spun pitch fiber, but the pitch fiber of the present invention uses optically anisotropic pitch with a high melting point, and When the cross-sectional shape of the fiber is non-circular (irregular), the surface area per unit cross-sectional area is large, so it is possible to reduce the processing time compared to conventional pitch fibers spun from a normal circular cross-section. . The thus infusible fibers are then fired in an inert gas at a temperature of usually 1,000 to 1,500°C to obtain the carbon fibers having three or more leaf structures according to the present invention. This product may be used as it is, but it can also be used after being further heated to about 3000°C to graphitize it. [Effects of the Invention] The pitch-based carbon fiber of the present invention as described above has a leaf-like lamellar arrangement in its cross-sectional area structure, which prevents cracks, and further allows smooth contraction during the infusibility and firing stages. , tensile strength,
The modulus increases dramatically, surpassing the physical properties of PAN-based carbon fiber. In addition, when the cross-sectional shape of the fiber is non-circular, the surface area increases, so adhesiveness is improved, and the fiber is suitably used as a reinforcing fiber for composite materials. Method for measuring each index Next, a method for measuring each index representing the spinning pitch and fiber properties in the present invention will be explained. (a) Melting point of spinning pitch using PerkinElmer DSC-1D model,
Put 10mg of fine Pitch powder crushed into 100 meshes or less into an aluminum cell (inner diameter 5m/m), press it down from above, and then heat it at the rate of temperature in a nitrogen atmosphere.
Measurement is carried out while raising the temperature to nearly 400℃ at 10℃/min.
The endothermic peak indicating the melting point in the DSC chart is taken as the melting point of the spinning pitch. (b) Amount of optical anisotropy of the spinning pitch Five arbitrary polarized micrographs of the spinning pitch were taken using a reflective polarizing microscope, and the area fraction (%) of the isotropic region was calculated using an image analysis processing device. and take the average value as the amount of optical anisotropy. (c) Physical properties of carbon fiber The fiber system (single fiber diameter), tensile strength, elongation, and modulus of carbon fiber are measured in accordance with JIS R-7601 "Carbon fiber testing method". The fiber diameter is measured using a laser for fibers with a circular cross section, and for fibers with a non-circular cross section, the average value of the cross-sectional area of n=15 is calculated from scanning electron micrographs. In addition, in Examples etc., the fiber diameter is expressed as a diameter when converted into a circle having a corresponding cross-sectional area. (d) Fraction of leaf-like lamellar arrangement From a scanning electron micrograph of a cross section of carbon fiber,
It is expressed as the area ratio of the leaf-like lamella array part per cross-sectional area. [Examples] Hereinafter, the present invention will be explained in more detail with reference to experimental examples, but the present invention is not limited to these examples in any way. The spinning holes of the spinneret used in each of the Examples and Comparative Examples described below are as shown in the following table. Note that θ in the table is the angle formed by each center line of the radial slit, expressed in radians.
【表】
実施例 １〜４
市販のコールタールピツチを原料とし、特開昭
59−53717号公報に記載の方法に準じ、全面流れ
構造で光学異方性量を88％有し、キノリン不溶部
39％、融点247℃の紡糸用ピツチを調製した。
該紡糸用ピツチを加熱ヒータを備えた定量フイ
ーダーに仕込み、溶融脱泡後、別に設けた加熱ゾ
ーンを経て、前掲の一覧表に示すＹ字形紡糸孔を
有する口金イを用いて、口金温度を変化させ紡糸
を行なつた。
この場合のフイーダー吐出量は0.06ml／分／
孔、フイーダー部温度（T1）＝320℃、加熱ゾー
ン温度（T2）＝320℃とし、口金温度（T3）は330
〜345℃の範囲内で変化させて紡糸し、引取り速
度800ｍ／分で巻きとつた。
このピツチ繊維をシリカ微粉末を融着防止剤と
して塗布した後、乾燥空気中にて10℃／分の昇温
速度で200℃から300℃まで昇温加熱し、300℃で
30分保持した。
次いで窒素雰囲気中にて500℃／分の昇温速度
で1300℃まで昇温加熱し、５分間保持することに
より焼成を行い炭素繊維とした。得られた繊維の
断面形状、リーフ状ラメラ分率及び物性を後掲の
第１表に示す。なお、この繊維の断面におけるリ
リーフ構造の数は３個であつた。
実施例 ５、６
実施例１と同じピツチを用い、前掲の一覧表に
示す十字形紡糸孔を有する口金ロを使用して実施
例１と同様に紡糸した。ただしT1＝320℃、T2＝
320℃、T3＝330℃又は345℃とし、引取り速度は
800ｍ／分とした。
次いで実施例１と同一の条件で不融化・焼成し
た後の炭素繊維の断面形状及び物性等を後掲の第
１表に示す。この繊維におけるリーフ構造の数は
４個であつた。
実施例 ７
前掲の一覧表に示す＊形紡糸孔を有する口金ハ
を用い、T3＝340℃で実施例１と同様に紡糸・不
融化・焼成を行つた。得られた炭素繊維の物性等
を後掲の第１表に示す。この繊維におけるリーフ
構造の数は合計６個であつた。[Table] Examples 1 to 4 Using commercially available coal tar pitch as raw material,
According to the method described in Publication No. 59-53717, it has a full-surface flow structure and an optical anisotropy of 88%, and a quinoline-insoluble part.
A spinning pitch of 39% and a melting point of 247°C was prepared. The spinning pitch is charged into a quantitative feeder equipped with a heating heater, and after melting and degassing, it passes through a separately provided heating zone, and then changes the temperature of the spinneret using a spinneret having a Y-shaped spinning hole as shown in the list above. Spinning was carried out. In this case, the feeder discharge amount is 0.06ml/min/
Hole and feeder temperature (T 1 ) = 320℃, heating zone temperature (T 2 ) = 320℃, mouth temperature (T 3 ) is 330℃.
The yarn was spun at varying temperatures within the range of ~345°C and wound at a take-up speed of 800 m/min. After applying fine silica powder as an anti-fusing agent to this pitch fiber, it was heated in dry air at a heating rate of 10°C/min from 200°C to 300°C.
Hold for 30 minutes. Next, the mixture was heated to 1300° C. at a heating rate of 500° C./min in a nitrogen atmosphere, and fired by holding for 5 minutes to obtain carbon fibers. The cross-sectional shape, leaf-like lamella fraction, and physical properties of the obtained fibers are shown in Table 1 below. Note that the number of relief structures in the cross section of this fiber was three. Examples 5 and 6 Using the same pitch as in Example 1, spinning was carried out in the same manner as in Example 1 using a spindle having a cross-shaped spinning hole as shown in the list above. However, T 1 = 320℃, T 2 =
320℃, T 3 = 330℃ or 345℃, and the take-up speed is
The speed was 800m/min. Next, the cross-sectional shape and physical properties of the carbon fibers after being infusible and fired under the same conditions as in Example 1 are shown in Table 1 below. The number of leaf structures in this fiber was four. Example 7 Spinning, infusibility, and sintering were carried out in the same manner as in Example 1 at T 3 =340° C. using a spinneret having *-shaped spinning holes shown in the list above. The physical properties of the obtained carbon fibers are shown in Table 1 below. The number of leaf structures in this fiber was six in total.
【表】
実施例 ８
市販の石油系ピツチ（アツシユランド240）か
ら、テトラハイドロフランに可溶でトルエンに不
溶な留分を取出して、窒素中440℃常圧で10分間
熱処理することによりキノリン不溶部35％、融点
272℃、光学異方性量85％の全面流れ構造の紡糸
用ピツチを得た。
該紡糸用ピツチを実施例１と同様にして、Ｙ字
形紡糸孔を有する口金イを用いT3＝340℃で紡糸
し引取り速度800ｍ／分で巻き取つた。実施例１
と同一条件で不融化・焼成をして得られた炭素繊
維の断面構造は実施例２と同じようなリーフ状ラ
メラ配列を90％以上有していた。その物性を後掲
の第２表に示す。
実施例 ９
市販のコールタールピツチからキノリンに可溶
でトルエンに不溶な留分を取出した後、撹拌中
460℃、10mmHg下で20分間減圧熱処理を施した。
得られたピツチは流れ構造を有しており、キノリ
ン不溶部42％、融点278℃、光学異方性量87％で
あつた。該紡糸用ピツチを実施例１と同様にして
Ｙ字形紡糸孔を有する口金イを用いて、T3＝340
℃で紡糸し引取り速度800ｍ／分で巻き取つた。
実施例１と同一条件で不融化・焼成した炭素繊
維の断面構造は３個のリーフ構造が認められたリ
ーフ状ラメラ配列の分率は90％以上であつた。そ
の物性を後掲の第２表に示す。
比較例 １
実施例１で用いた紡糸用ピツチを加熱ヒーター
を備えた定量フイーダに仕込み、溶融脱泡後、加
熱ゾーンを経て、直径180μｍの円形断面紡糸孔
を有する口金を用い、吐出量0.06ml／分／孔、T1
＝T2＝320℃、T3＝340℃で紡糸し、引取り速度
800ｍ／分で巻き取つた。
このピツチ繊維を実施例１と同一条件で不融
化・焼成を行つたところ、繊維断面はラジアル構
造で、角度120゜程度のクラツクが生じており、リ
ーフ構造は全く認められなかつた。その物性を第
２表に示したが、本発明のものに比べて著しく低
い値となつた。
比較例 ２
実施例９で得られた融点278℃の紡糸ピツチを
用い、直径180μｍの円形断面紡糸孔を有する口
金を用いて、実施例１と同様にT3＝340℃で紡糸
し、引取り速度800ｍ／分で巻き取つた。
このピツチ繊維を実施例１と同一条件で不融化
焼成したところ、繊維断面はラジアル構造で、
120゜以上の角度を有するクラツクが生じていた。
その物性を第２表に示したが、引張り強度300
Kg／mm2未満であつた。
比較例 ３
実施例１で得られた紡糸用ピツチを、前掲の一
覧表に示した＊形の紡糸孔を有する口金ニを用
い、実施例１と同様にしてT1＝T2＝320℃、T3
＝340℃で紡糸し、引取り速度800ｍ／分で巻き取
つた。
このピツチ繊維を実施例１と同一条件で不融
化・焼成したところ、繊維断面は、クラツクを有
し、ほとんどラジアル構造で、リーフ構造は外周
部に10％以下存在する程度であつた。
実施例 10、11
溶融紡糸時にT1＝340℃、T2＝は360℃、T3＝
340℃となし引取り速度を、1000ｍ／分（実施例
11）、1200ｍ／分（実施例12）と変化させた以外
は実施例１と同一条件で紡糸し、不融化・焼成を
実施した。得られた炭素繊維の物性を第２表に示
す。[Table] Example 8 A fraction soluble in tetrahydrofuran and insoluble in toluene was extracted from a commercially available petroleum-based pitch (Asshuland 240) and heat-treated in nitrogen at 440°C and normal pressure for 10 minutes to obtain the quinoline-insoluble fraction. 35%, melting point
A spinning pitch with a full flow structure at 272°C and an optical anisotropy of 85% was obtained. The spinning pitch was prepared in the same manner as in Example 1, using a spinneret having a Y-shaped spinning hole at T 3 =340° C. and winding at a take-up speed of 800 m/min. Example 1
The cross-sectional structure of the carbon fiber obtained by infusibility and firing under the same conditions as in Example 2 had the same leaf-like lamella arrangement as in Example 2 at 90% or more. Its physical properties are shown in Table 2 below. Example 9 After extracting a fraction soluble in quinoline and insoluble in toluene from commercially available coal tar pitch,
A vacuum heat treatment was performed at 460°C and 10 mmHg for 20 minutes.
The resulting pitch had a flow structure, had a quinoline insoluble area of 42%, a melting point of 278°C, and an optical anisotropy of 87%. The spinning pitch was made in the same manner as in Example 1, using a spindle A having a Y-shaped spinning hole, and T 3 =340.
The yarn was spun at ℃ and wound at a take-up speed of 800 m/min. In the cross-sectional structure of the carbon fiber made infusible and fired under the same conditions as in Example 1, the fraction of leaf-like lamella arrangement in which three leaf structures were observed was 90% or more. Its physical properties are shown in Table 2 below. Comparative Example 1 The spinning pitch used in Example 1 was charged into a metering feeder equipped with a heating heater, and after melting and degassing, it passed through a heating zone, using a spinneret with a circular cross-sectional spinning hole of 180 μm in diameter, and the discharge amount was 0.06 ml. /min/hole, T 1
= T 2 = 320℃, T 3 = 340℃ spinning, take-up speed
It was wound up at 800m/min. When this pitch fiber was infusible and fired under the same conditions as in Example 1, the fiber cross section had a radial structure with cracks at an angle of about 120°, and no leaf structure was observed. The physical properties are shown in Table 2, and the values were significantly lower than those of the present invention. Comparative Example 2 Using the spinning pitch with a melting point of 278°C obtained in Example 9, spinning was carried out at T 3 = 340°C in the same manner as in Example 1 using a spinneret having a circular cross-section spinning hole with a diameter of 180 μm, and the yarn was taken off. It was wound up at a speed of 800 m/min. When this pitch fiber was infusible and fired under the same conditions as in Example 1, the fiber cross section had a radial structure.
Cracks with angles of 120° or more were occurring.
Its physical properties are shown in Table 2, and the tensile strength is 300
It was less than Kg/ mm2 . Comparative Example 3 The spinning pitch obtained in Example 1 was treated in the same manner as in Example 1, using a spinneret D having *-shaped spinning holes shown in the list above, at T 1 =T 2 =320°C, T3
The yarn was spun at =340°C and wound at a take-up speed of 800 m/min. When this pitch fiber was infusible and fired under the same conditions as in Example 1, the cross section of the fiber had cracks, was almost a radial structure, and leaf structures were present in less than 10% of the outer periphery. Examples 10 and 11 During melt spinning, T 1 = 340°C, T 2 = 360°C, T 3 =
340℃ and take-up speed of 1000 m/min (example)
11) and 1200 m/min (Example 12), spinning was carried out under the same conditions as in Example 1, and infusibility and firing were carried out. Table 2 shows the physical properties of the obtained carbon fiber.
【表】
＊ やや円形に近いトライアングル
[Table] * Slightly circular triangle
第１図〜第４図は、それぞれ本発明のピツチ系
炭素繊維の断面構造を模式的に示す見取図であ
り、図中のＡがリーフ状ラメラ配列を有するリー
フ構造の部分を示す。第５図〜第７図は、それぞ
れ本発明のピツチ系炭素繊維における断面の走査
型電子顕微鏡写真である。第８図〜第１１図は、
それぞれ本発明のピツチ系炭素繊維を製造する際
に使用する紡糸口金の紡糸孔の形状を例示する説
明図であり、図中のL1，L2…L6はスリツトの中
心線距離、W1，W2…W6はぬれぶち幅を示す。
1 to 4 are diagrams schematically showing the cross-sectional structure of the pitch-based carbon fiber of the present invention, and A in the figures indicates a portion of the leaf structure having a leaf-like lamella arrangement. FIGS. 5 to 7 are scanning electron micrographs of cross sections of pitch-based carbon fibers of the present invention, respectively. Figures 8 to 11 are
Each is an explanatory diagram illustrating the shape of the spinning hole of the spinneret used when manufacturing the pitch-based carbon fiber of the present invention, and L 1 , L 2 ...L 6 in the diagram are the centerline distances of the slits, and W 1 , W 2 ... W 6 indicate the wet edge width.
Claims (1)
紡糸し、不融化・焼成してなるピツチ系炭素繊維
であつて、繊維断面の少なくとも30％以上の部分
に合計３個以上リーフ状ラメラ配列を有し、かつ
引張り強度が300Kg／mm2以上であることを特徴と
するピツチ系炭素繊維。 ２ 繊維の断面形状が実質的に円形である特許請
求の範囲第１項記載のピツチ系炭素繊維。 ３ 繊維の断面形状がマルチアングル形である特
許請求の範囲第１項記載のピツチ系炭素繊維。 ４ 繊維の断面形状がマルチローバル形である特
許請求の範囲第１項記載のピツチ系炭素繊維。 ５ 強度が400Kg／mm2以上で、かつモジユラスが
15T／mm2以上である特許請求の範囲第１項又は第
２項記載のピツチ系炭素繊維。[Scope of Claims] 1 Pitch-based carbon fiber made by melt-spinning, infusible and firing pitches having an optical anisotropy of 50% or more, which comprises a total of 3 pitches in at least 30% or more of the fiber cross section. A pitch-based carbon fiber characterized by having a leaf-like lamella arrangement as described above and having a tensile strength of 300 Kg/mm 2 or more. 2. The pitch-based carbon fiber according to claim 1, wherein the cross-sectional shape of the fiber is substantially circular. 3. The pitch-based carbon fiber according to claim 1, wherein the fiber has a multi-angle cross-sectional shape. 4. The pitch-based carbon fiber according to claim 1, wherein the cross-sectional shape of the fiber is multilobal. 5 Strength is 400Kg/ mm2 or more and modulus is
The pitch-based carbon fiber according to claim 1 or 2, which has a particle diameter of 15T/mm 2 or more.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59125048A JPS616314A (en) | 1984-06-20 | 1984-06-20 | Pitch carbon fiber |
| US06/719,585 US4628001A (en) | 1984-06-20 | 1985-04-03 | Pitch-based carbon or graphite fiber and process for preparation thereof |
| KR1019850002514A KR920003251B1 (en) | 1984-06-20 | 1985-04-15 | Pitch-based carbon of graphite fiber and process for preparation thereof |
| DE8585107334T DE3576969D1 (en) | 1984-06-20 | 1985-06-13 | CARBON OR GRAPHITE FIBERS BASED ON PECH AND METHOD FOR THE PRODUCTION THEREOF. |
| EP85107334A EP0168639B1 (en) | 1984-06-20 | 1985-06-13 | Pitch-based carbon of graphite fiber and process for preparation thereof |
| JP1008609A JPH02216222A (en) | 1984-06-20 | 1989-01-19 | High-strength, high-modulus pitch-based carbon fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59125048A JPS616314A (en) | 1984-06-20 | 1984-06-20 | Pitch carbon fiber |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23007384A Division JPS616316A (en) | 1984-11-02 | 1984-11-02 | Graphite fiber |
| JP1008609A Division JPH02216222A (en) | 1984-06-20 | 1989-01-19 | High-strength, high-modulus pitch-based carbon fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS616314A JPS616314A (en) | 1986-01-13 |
| JPH0370012B2 true JPH0370012B2 (en) | 1991-11-06 |
Family
ID=14900542
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59125048A Granted JPS616314A (en) | 1984-06-20 | 1984-06-20 | Pitch carbon fiber |
| JP1008609A Granted JPH02216222A (en) | 1984-06-20 | 1989-01-19 | High-strength, high-modulus pitch-based carbon fiber |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1008609A Granted JPH02216222A (en) | 1984-06-20 | 1989-01-19 | High-strength, high-modulus pitch-based carbon fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (2) | JPS616314A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5682570B2 (en) * | 2010-10-13 | 2015-03-11 | 三菱レイヨン株式会社 | Carbon fiber precursor fiber bundle, carbon fiber bundle, and use thereof |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS616313A (en) * | 1984-06-20 | 1986-01-13 | Teijin Ltd | Production of pitch carbon fiber |
| JPS616316A (en) * | 1984-11-02 | 1986-01-13 | Teijin Ltd | Graphite fiber |
| JPS6213330A (en) * | 1985-07-11 | 1987-01-22 | 工業技術院長 | Composite material reinforced by carbon fiber |
| US5154908A (en) * | 1985-09-12 | 1992-10-13 | Clemson University | Carbon fibers and method for producing same |
| JPS62131034A (en) * | 1985-12-03 | 1987-06-13 | Osaka Gas Co Ltd | Carbon fiber/resin composite |
| JPS62170526A (en) * | 1986-01-22 | 1987-07-27 | Osaka Gas Co Ltd | Production of carbon fiber having elliptic cross-section |
| US4859382A (en) * | 1986-01-22 | 1989-08-22 | Osaka Gas Company Limited | Process for preparing carbon fibers elliptical in section |
| JP4987755B2 (en) * | 2008-02-26 | 2012-07-25 | Ｊｆｅケミカル株式会社 | Method for producing fibrous pitch and method for producing carbon fiber |
| CN102317516A (en) | 2008-12-19 | 2012-01-11 | 帝人株式会社 | Carbon fibers and method for producing the same |
| WO2015175251A1 (en) | 2014-05-12 | 2015-11-19 | Summit Mining International Inc. | Brine leaching process for recovering valuable metals from oxide materials |
| WO2022255466A1 (en) | 2021-06-02 | 2022-12-08 | 日本製鉄株式会社 | Pitch-based carbon fiber, method for producing same, and fiber-reinforced plastic |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59168126A (en) * | 1983-03-14 | 1984-09-21 | Toray Ind Inc | Production of pitch based carbon fiber |
| JPS616313A (en) * | 1984-06-20 | 1986-01-13 | Teijin Ltd | Production of pitch carbon fiber |
-
1984
- 1984-06-20 JP JP59125048A patent/JPS616314A/en active Granted
-
1989
- 1989-01-19 JP JP1008609A patent/JPH02216222A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59168126A (en) * | 1983-03-14 | 1984-09-21 | Toray Ind Inc | Production of pitch based carbon fiber |
| JPS616313A (en) * | 1984-06-20 | 1986-01-13 | Teijin Ltd | Production of pitch carbon fiber |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5682570B2 (en) * | 2010-10-13 | 2015-03-11 | 三菱レイヨン株式会社 | Carbon fiber precursor fiber bundle, carbon fiber bundle, and use thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0529689B2 (en) | 1993-05-06 |
| JPH02216222A (en) | 1990-08-29 |
| JPS616314A (en) | 1986-01-13 |
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