JPH0229765B2 - - Google Patents
Info
- Publication number
- JPH0229765B2 JPH0229765B2 JP57040040A JP4004082A JPH0229765B2 JP H0229765 B2 JPH0229765 B2 JP H0229765B2 JP 57040040 A JP57040040 A JP 57040040A JP 4004082 A JP4004082 A JP 4004082A JP H0229765 B2 JPH0229765 B2 JP H0229765B2
- Authority
- JP
- Japan
- Prior art keywords
- pitch
- solvent
- insoluble
- mesophase
- insoluble phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000011295 pitch Substances 0.000 claims description 73
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 claims description 40
- 239000002904 solvent Substances 0.000 claims description 34
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 32
- 239000004917 carbon fiber Substances 0.000 claims description 32
- 239000000203 mixture Substances 0.000 claims description 28
- 239000000126 substance Substances 0.000 claims description 18
- 125000003118 aryl group Chemical group 0.000 claims description 17
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 17
- 125000001931 aliphatic group Chemical group 0.000 claims description 15
- 239000013078 crystal Substances 0.000 claims description 15
- 239000003849 aromatic solvent Substances 0.000 claims description 12
- 239000011280 coal tar Substances 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000009835 boiling Methods 0.000 claims description 5
- 239000011294 coal tar pitch Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 2
- 239000002994 raw material Substances 0.000 description 21
- 238000010438 heat treatment Methods 0.000 description 19
- 238000009826 distribution Methods 0.000 description 7
- 239000000835 fiber Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- 239000003921 oil Substances 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 6
- 239000012299 nitrogen atmosphere Substances 0.000 description 6
- 238000009987 spinning Methods 0.000 description 6
- 239000002244 precipitate Substances 0.000 description 5
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 description 4
- 238000003763 carbonization Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000003245 coal Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000003502 gasoline Substances 0.000 description 2
- 238000005227 gel permeation chromatography Methods 0.000 description 2
- 238000005087 graphitization Methods 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- YNPNZTXNASCQKK-UHFFFAOYSA-N phenanthrene Chemical compound C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000011338 soft pitch Substances 0.000 description 2
- -1 that is Substances 0.000 description 2
- WHRZCXAVMTUTDD-UHFFFAOYSA-N 1h-furo[2,3-d]pyrimidin-2-one Chemical compound N1C(=O)N=C2OC=CC2=C1 WHRZCXAVMTUTDD-UHFFFAOYSA-N 0.000 description 1
- 235000006173 Larrea tridentata Nutrition 0.000 description 1
- 244000073231 Larrea tridentata Species 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical group 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229960002126 creosote Drugs 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000010763 heavy fuel oil Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Landscapes
- Working-Up Tar And Pitch (AREA)
- Inorganic Fibers (AREA)
Description
本発明は石炭系原料からの炭素繊維の製造法に
関する。
更に詳しくは石炭系原料であるコールタール及
び／又はコールタールピツチを溶媒処理すること
により、炭素繊維として有用なる留分を回収し、
すぐれた炭素繊維を製造する方法に関する。
近年炭素繊維は、金属あるいはプラスチツクと
の複合材料としてその性能を高く評価されている
が、より低コストであることが要求されている。
そのため最近では、安価な原料であるピツチを用
いたピツチ系の高級炭素繊維ついて、原料調製方
法あるいは繊維製造方法の面から盛んに研究が行
われている。
ピツチ系高級炭素繊維、すなわちピツチ系の高
弾性率高強度炭素繊維は、ピツチの熱処理過程で
生成する液晶状態の易黒鉛化性炭素結晶であるメ
ゾフエーズ（偏光顕微鏡下で光学異方性領域とし
あ確認される。）を繊維軸に平行に配向させた状
態に製造するが、この場合、生成するメゾフエー
ズの均質性及び熱可塑性が重要である。
しかしながら通常のピツチ類は、低分子から高
分子までかなり幅の広い分子量分布を有してお
り、一般に一定の大きさにまで熱重縮合の進んだ
分子から順次メゾフエーズの形成に加わるので、
当該ピツチ内においてメゾフエーズの発達に時間
差を生じると同時に、該炭素繊維原料として充分
に結晶化させるのに長い時間を要する。したがつ
て、当該原料のピツチ所定量がメゾフエーズに転
化するまでの間に、初期に生成したメゾフエーズ
が過剰な熱処理を受ける結果、当該メゾフエーズ
は液晶状態を通り越して熱可塑性に劣る炭素結晶
へと変化してしまう。このような炭素結晶の存在
はピツチ全体の均一な熱可塑性を低下させるのみ
でなく、紡糸成形の際に、糸切れあるいは節の原
因となるので好ましくない。
ところで、炭素繊維に紡糸するためのピツチが
均質でかつ高い熱可塑性を示めすためには、当該
ピツチ中の易黒鉛化成分の成長度合が均一で、し
かもピツチ相と同程度に高い熱可塑性を有してい
なくてはならない。ピツチ中の易黒鉛化成分であ
るメゾフエーズの成長度合がより均質であるため
にはメゾフエーズ形成に加わる分子のサイズが揃
つている。すなわち芳香族組成物である原料ピツ
チの分子量分布の巾が狭いことが要求される。又
当該メゾフエーズ含有ピツチが高い熱可塑性を示
めすためには、より低温、短時間の熱処理によ
り、所定量のメゾフエーズを均質に生成せしめる
ことが重要であるが、そのためには、メゾフエー
ズを形成させる前の芳香族組成物である原料ピツ
チの平均分子量を出来るだけ高くしておき、生成
するメゾフエーズを含有するピツチが、過剰な熱
処理を受けないようにする必要がある。
本発明者等は、芳香族組成物である原料ピツチ
を250℃ないし500℃の温度範囲の熱処理の前に、
芳香族系溶媒と脂肪族系溶媒の混合溶媒による有
機溶媒処理（本出願人による特開昭53−66901に
記載の処理）を施すことによりその際に析出する
ピツチゾーン又はクリスタルゾーンでの不溶性相
が比較的揃つた分子量を有することに着目し、本
発明を完成させたものである。これにより、より
結晶性にすぐれ、充分に均質でしかも高い熱可塑
性を有するピツチを製造することが出来る。
又用途に応じてピツチ中のメゾフエーズを粒径
の大きなものから小さなものまで自由に整粒する
ことが出来る。
この様にして得たピツチを用いて、炭素繊維に
紡糸し、不融化処理後、焼成して得た炭素繊維は
すぐれた性能を有しているのである。
すなわち本発明は
コールタール又はコールタールピツチから選ば
れた芳香族組成物に、芳香族系溶媒と脂肪族系溶
媒とを混合し、ピツチゾーン又はクリスタルゾー
ンから析出する不溶性相を回収し、これに含有す
るキノリン不溶の物質を除去したのち、該回収物
を常圧又は減圧下で蒸留して低沸点留分を除去し
て得られたピツチを加熱処理し、次いで溶融紡糸
し、不融化し、更に焼成することを特徴とする炭
素繊維の製造方法。である。
ここで言うキノリンに不溶の物質とは、原料で
ある芳香族組成物中に含有されている固体微粒子
で主としてコークス、カーボンブラツク等からな
るもので、一般に難黒鉛化性で１次QIと言われ
ているものである。
この様な１次QIが原料中に存在すると、２次
的に発生する易黒鉛化性成分であるメゾフエーズ
の生長が阻害される。本発明において、その様な
１次QIの含有量が0.1重量％以下であれば、メゾ
フエーズの生長をさほど阻害しないが、0.1重量
％以上の１次QIを含有する原料を使用する場合
には該メゾフエーズの生長が阻害されるので該
QIを除去しておく必要がある。しかも、該１次
QIの如く難黒鉛化性成分が存在すると炭素繊維
とした時にその物性は著しく低下する。
本発明の炭素繊維の製造法は、芳香族系組成物
としての原料ピツチを、あらかじめ芳香族溶媒と
脂肪族溶媒を混合し、それにより析出する不溶性
相を利用する。この様な本発明の処理を行なうこ
とにより巾の狭い分子量分布で且つ高い平均分子
量を有するピツチが得られる。これはゲル浸透ク
ロマトグラフイーを用いて簡単に確認することが
出来る。
ここでこの不溶性相の析出状態の概念を説明す
る。本出願人による特開昭53−66901号を参照し
てもらえばよいが、ここに要部を説明する。
本発明者等は、従来より知られているピツチ類
の溶剤分析を詳細に検討している間に、以下に述
べる重大な事実を発見した。すなわち、例えばコ
ールタールのような芳香族系組成物を溶剤分析す
るに当り、その組成物と芳香族系溶媒に対して貧
溶媒である脂肪族系溶媒を、その組成物に加温状
態で芳香族系溶媒と同時に混合し、次いで放冷ま
たは冷却することにより不溶性相物質が生成す
る。ただし、この時の各溶媒の組合せと芳香族系
組成物との構成比率は適当に選択しなければなら
ない。
芳香族系組成物に対する溶媒の混合による不溶
性相の析出状態の理解のために、組成図を用いて
説明する。以下、本文中の記号は、その時点での
第１図中の組成点に対応する。
芳香族系組成物と芳香族溶媒を、その溶媒の沸
点以下の温度に加熱しながら混合し、放冷または
冷却する（Ａ点）。この混合物は、通常常温では
液状である。これに脂肪族系溶媒を徐々に添加し
て行くと、Ｂ点で板状結晶様の不溶性相の析出が
始まる。さらに脂肪族系溶媒を加え続けると、Ｃ
点では析出した不溶性相は粘着性を帯び始め、Ｄ
点では黒色ピツチ状物質が容器の底部に沈着する
ようになる。Ｄ点以後は、脂肪族系溶媒を加え続
けても、不溶性相の状態は変化しない。Ｄ点の組
成物に、芳香族系溶媒を混合加熱し、放冷または
冷却すると、Ｅ点で再び粘着性のある板状結晶様
の不溶性相が析出し、さらに芳香族系溶媒を加え
ると、粘着性のない板状結晶様の不溶性相となる
（Ｆ点）。次いで加える溶媒を、脂肪族系に戻す
と、Ｇ点に至り不溶性相は粒状に変わり始め、Ｈ
点以後では全て粒状になる。
このような溶媒の混合による不溶性相の析出状
態の変化において、Ａ点からＢ点までの領域は、
場合によつては油状のものが沈降するので、オイ
リゾーンと称する。Ｂ点からＣ点までの領域では
板状結晶様の析出物となるので、クリスタルゾー
ンと称し、Ｄ点の存在する領域では黒色ピツチ状
物質が現われるので、ピツチゾーンと称する。前
述の説明通り、Ｅ点からＦ点を経てＧ点に至る間
は、再びクリスタルゾーンであるが、Ｈ点の存在
する領域での不溶性相はスラリ状を呈するので、
スラリゾーンと称する。
本発明で使用するピツチゾーン又はクリスタル
ゾーンでの析出物である不溶性相は黒色ピツチ状
又は結晶状を呈し、容器底部に沈澱し、通常芳香
族組成物の軟化点（Ｒ＆Ｂ法）以上の軟化点を示
すが、不溶性相の分離そのものは極めて容易であ
る。これは脂肪族系溶媒の添加による効果であ
る。
これらの各領域の範囲は使用する溶媒の組合せ
によつても変わる。その例を第１表例１、例２に
示す。第２表に例挙するような相互に完全には溶
解せず或る割合の組成では、一方の成分が析出す
るような溶媒の組合せにおいては、芳香族系組成
物と芳香族系溶媒を混合し、次いで脂肪族系溶媒
を混合する際、その添加につれて同様に不溶性相
を析出させることも出来る。
The present invention relates to a method for producing carbon fiber from coal-based raw materials. More specifically, by treating coal tar and/or coal tar pitch, which are coal-based raw materials, with a solvent, a fraction useful as carbon fibers is recovered,
This invention relates to a method for producing excellent carbon fiber. In recent years, carbon fiber has been highly evaluated for its performance as a composite material with metal or plastic, but there is a demand for lower cost.
Therefore, recently, research has been actively conducted on pitch-based high-grade carbon fibers using pitch, which is an inexpensive raw material, from the viewpoint of raw material preparation methods and fiber manufacturing methods. Pitch-based high-grade carbon fibers, that is, pitch-based high-modulus, high-strength carbon fibers, are mesophase (optically anisotropic regions) which are easily graphitized carbon crystals in a liquid crystal state that are produced during the heat treatment process of pitch. ) is produced in a state in which it is oriented parallel to the fiber axis, but in this case, the homogeneity and thermoplasticity of the mesophase produced are important. However, ordinary pitts have a fairly wide molecular weight distribution ranging from low molecules to polymers, and generally participate in the formation of mesophases in the order of molecules that have undergone thermal polycondensation to a certain size.
There is a time lag in the development of mesophase within the pitch, and at the same time it takes a long time to sufficiently crystallize the carbon fiber raw material. Therefore, until a predetermined amount of the raw material is converted into mesophase, the initially generated mesophase undergoes excessive heat treatment, and as a result, the mesophase passes through the liquid crystal state and changes to carbon crystals with poor thermoplasticity. Resulting in. The presence of such carbon crystals not only reduces the uniform thermoplasticity of the entire pitch, but also causes yarn breakage or knots during spinning and forming, which is undesirable. By the way, in order for the pitch for spinning into carbon fiber to be homogeneous and to exhibit high thermoplasticity, the degree of growth of the easily graphitizable component in the pitch must be uniform, and the pitch must have as high thermoplasticity as the pitch phase. must have. In order for the degree of growth of mesophases, which are easily graphitized components in pitch, to be more uniform, the sizes of the molecules that participate in mesophase formation are uniform. That is, it is required that the molecular weight distribution of the raw material pitch, which is an aromatic composition, be narrow. In order for the mesophase-containing pitch to exhibit high thermoplasticity, it is important to uniformly generate a predetermined amount of mesophase by heat treatment at a lower temperature and for a shorter time. It is necessary to keep the average molecular weight of the raw material pitch, which is an aromatic composition, as high as possible so that the produced pitch containing mesophase is not subjected to excessive heat treatment. The present inventors have discovered that before heat-treating the raw material pitch, which is an aromatic composition, in a temperature range of 250°C to 500°C,
By applying an organic solvent treatment using a mixed solvent of an aromatic solvent and an aliphatic solvent (the treatment described in JP-A No. 53-66901 by the present applicant), the insoluble phase in the pitch zone or crystal zone that precipitates at that time can be removed. The present invention was completed by focusing on the fact that they have relatively uniform molecular weights. As a result, it is possible to produce a pitch that has better crystallinity, is sufficiently homogeneous, and has high thermoplasticity. In addition, the mesophase in the pitch can be freely sized from large to small particle sizes depending on the application. The pitch thus obtained is spun into carbon fibers, and the carbon fibers obtained by infusibility treatment and firing have excellent performance. That is, the present invention involves mixing an aromatic solvent and an aliphatic solvent with an aromatic composition selected from coal tar or coal tar pitch, collecting the insoluble phase precipitated from the pitch zone or the crystal zone, and adding the After removing the quinoline-insoluble substances, the recovered product is distilled under normal pressure or reduced pressure to remove low-boiling fractions, and the resulting pitch is heat-treated, then melt-spun to make it infusible, and then A method for producing carbon fiber, which comprises firing. It is. The substances insoluble in quinoline referred to here are solid fine particles contained in the aromatic composition that is the raw material, mainly consisting of coke, carbon black, etc., and are generally non-graphitizable and are referred to as primary QI. It is something that When such primary QI exists in the raw material, the growth of mesophase, which is a secondarily generated graphitizable component, is inhibited. In the present invention, if the content of such primary QI is 0.1% by weight or less, the growth of mesophase is not significantly inhibited, but if a raw material containing primary QI of 0.1% by weight or more is used, This is because the growth of mesophase is inhibited.
QI must be removed. Moreover, the first order
If a non-graphitizable component such as QI is present, the physical properties of carbon fiber will be significantly reduced. The method for producing carbon fibers of the present invention utilizes an insoluble phase precipitated by mixing a raw material pitch as an aromatic composition with an aromatic solvent and an aliphatic solvent in advance. By carrying out the treatment of the present invention, pitches having a narrow molecular weight distribution and a high average molecular weight can be obtained. This can be easily confirmed using gel permeation chromatography. Here, the concept of the precipitation state of this insoluble phase will be explained. Please refer to Japanese Patent Application Laid-Open No. 53-66901 by the present applicant, but the main parts will be explained here. The present inventors discovered the following important fact while conducting a detailed study on the conventionally known solvent analysis of pitches. That is, when analyzing the solvent of an aromatic composition such as coal tar, an aliphatic solvent, which is a poor solvent for the composition and the aromatic solvent, is added to the composition under heating. An insoluble phase substance is produced by simultaneously mixing with a family solvent and then allowing or cooling the mixture. However, at this time, the composition ratio of each solvent combination and the aromatic composition must be appropriately selected. In order to understand the state of precipitation of an insoluble phase due to mixing of a solvent with an aromatic composition, explanation will be made using a composition diagram. Hereinafter, the symbols in the text correspond to the composition points in FIG. 1 at that time. The aromatic composition and the aromatic solvent are mixed while being heated to a temperature below the boiling point of the solvent, and then left to cool or cooled (point A). This mixture is usually liquid at room temperature. When an aliphatic solvent is gradually added to this, a plate-shaped crystal-like insoluble phase begins to precipitate at point B. If you continue to add more aliphatic solvent, C
The precipitated insoluble phase begins to become sticky at point D
At points, a black pock-like substance begins to settle at the bottom of the container. After point D, the state of the insoluble phase does not change even if the aliphatic solvent is continued to be added. When an aromatic solvent is mixed and heated to the composition at point D and allowed to cool or cooled, a sticky plate crystal-like insoluble phase precipitates again at point E, and when an aromatic solvent is further added, It becomes an insoluble phase like a plate crystal without stickiness (point F). Then, when the added solvent is returned to the aliphatic system, it reaches the G point, the insoluble phase begins to turn into particulate, and the H
Everything after this point becomes granular. In such a change in the precipitation state of the insoluble phase due to mixing of solvents, the area from point A to point B is as follows:
In some cases, oily substances settle out, so it is called an oily zone. In the region from point B to point C, a plate-like crystal-like precipitate is formed, so it is called a crystal zone, and in the region where point D exists, a black pitch-like substance appears, so it is called a pitch zone. As explained above, the period from point E through point F to point G is again a crystal zone, but the insoluble phase in the region where point H exists takes on a slurry state.
It is called the slurry zone. The insoluble phase, which is a precipitate in the pitch zone or crystal zone used in the present invention, has a black pitch or crystal shape, settles at the bottom of the container, and usually has a softening point higher than the softening point of the aromatic composition (R&B method). As shown, separation of the insoluble phase itself is extremely easy. This is the effect of adding an aliphatic solvent. The range of each of these regions also varies depending on the combination of solvents used. Examples are shown in Table 1, Example 1 and Example 2. In combinations of solvents such as those listed in Table 2, where one component will precipitate at a certain composition without completely dissolving each other, an aromatic composition and an aromatic solvent may not be mixed together. However, when subsequently mixing an aliphatic solvent, an insoluble phase can be similarly precipitated as the aliphatic solvent is added.
【表】【table】
【表】【table】
【表】【table】
【表】
このような溶媒処理によつて、本発明において
使用する不溶性相は極めて容易に回収される。
次に本発明について詳述する。
芳香族系組成物としては、コールタール及びま
たはコールタールピツチを出発原料とし、それに
芳香族系溶媒と脂肪族系溶媒とを、常圧下常温か
ら250℃で混合すると、前述の組成図のピツチゾ
ーン又はクリスタルゾーンにおいて、不溶性相が
生ずる。本発明においてはこの不溶性物質を使用
するが、キノリン不溶分である物質を0.1重量％
以上含む原料からの不溶性相を使用する場合は、
過又は遠心分離等の手段で、該原料又は溶媒処
理によりピツチゾーン又はクリスタルゾーンで析
出した不溶性相中に含まれるキノリンに不溶の物
質を除去する。
本発明に使用するコールタールとは、石炭の高
温乾留時に生成するもので、又コールタールピツ
チとは、これを蒸留し軽質油分を留去したもので
ある。本発明に使用する芳香族系溶媒は、何ら限
定されるものではなく、ベンゼン・トルエン・キ
シレン・ナフタレン・アントラセン・フエナント
レンあるいはそれらの混合物等、構成成分が芳香
族炭化水素であればよいが、通常コールタール蒸
留で得られるクレオソート油、アントラセン油或
はデイレードコーカー副生油など比較的重質油が
好ましい。一方、脂肪族系溶媒においても、ｎ−
ヘキサン・ナフサ・灯軽油・燃料重油等、構成成
分が脂肪族炭化水素であれば何ら限定されること
はない。分離帯域における不溶性相の回収には、
静置分離・液体サイクロン・過・遠心分離等あ
るいはそれらの組合せ方式が採用出来る。
本発明で使用する不溶性相は、溶媒処理する前
の原料にくらべてそれ自体高い平均分子量と比較
的シヤープな分子量分布を有している。更にそれ
等の特性を高めるために本発明では常圧或は減圧
蒸留操作を適宜調整して、要求される用途に応じ
て、より高い平均分子量とシヤープな分子量分布
を持つようにする。
この様にして調整された不溶性相は250℃から
500℃好ましくは300℃〜450℃の温度範囲で熱処
理するが、前述の如く分子量が揃つているために
該加熱により比較的短時間で均質なメゾフエーズ
が形成される。加熱温度が500℃以上であると、
結晶化の進行程度をコントロールするには、結晶
化への速度が早すぎるので、あまり適当であると
は言えない。250℃以下の加熱温度でも良いが、
易黒鉛化性成分であるメゾフエーズを形成させる
には時間がかかり過ぎる。該温度で加熱する時間
は本発明により製造するピツチが、流動試験器で
の測定で200℃〜400℃の温度でも流動性を示めす
までの時間とする。加熱時間は、加熱温度にもよ
るが10分〜５時間程度である。
メゾフエーズの粒径の大小を調整するには、加
熱温度と時間を制御する。例えば約250℃〜380℃
という低温度で長時間の処理を行えば、小径メゾ
フエースが多量に生成する。又、処理温度を高く
すれば、メゾフエースの生成が早くなり、大径メ
ゾフエースとなる。いづれの場合も蒸留して事前
に溶剤処理した原料ピツチを濃縮しておけば、該
加熱時間を短縮することが出来る。
この様にして製造したピツチを偏光顕微鏡で観
察すれば均一に整粒された光学異方性を有するメ
ゾフエースを含有していることがわかる。この様
に加熱温度及び加熱時間を調整することによりメ
ゾフエースの粒径及び熱可塑性を各用途に応じて
自由にコントロールすることが出来る。
本発明で使用する炭素繊維用のピツチとして
は、あまりメゾフエーズが巨大でない方が好まし
い。本発明で使用するピツチ中のメゾフエーズ
は、偏光顕微鏡の200倍の倍率でメゾフエーズが
確認出来ないか、又は初めてメゾフエーズの存在
が確認出来る程度のピツチを使用するのが好まし
い。すなわち、ピツチ中に存在するメゾフエーズ
の径が紡糸繊維の径より大きくなると、該繊維の
紡糸中に該部分で節或はボイドとなり連続紡糸が
行なえず、しかも焼成して炭素繊維としても引張
り強度が弱くなり、炭素繊維本来の性能が発揮し
得ないためである。
本発明の方法で製造したピツチを250〜400℃の
温度範囲で溶融し、ノズルより押出し、紡糸す
る。その後通常の如く200〜300℃で、該紡糸した
繊維を不融化し、次いで不活性気相中で1000〜
1500℃で炭化し、必要に応じて更に2000℃以上で
黒鉛化して炭素繊維を製造する。
本発明により製造した炭素繊維は、炭化及び黒
鉛化工程における温度を適宜選択することによ
り、汎用型、或は高品質炭素繊維を製造すること
が出来る。
本発明の炭素繊維の製造法は炭素繊維用の原料
調整に特徴を有するもので原料を溶媒処理し、そ
の分子量分布を出来るだけ揃えることにより、該
原料の均質化を計るものであり、それにより製造
した炭素繊維は高強度でしかも、均質な品質のも
のが製造出来るものである。
次に本発明を実施例をもつて説明する。
実施例 １
操作１ 軟化点25℃、キノリンに不溶の物質を
2.1重量％を含むコールタール軟ピツチ１部に芳
香族系軽油（JIS Ｋ−2254による初留点191℃、
乾点328℃）を1/5部加え、120℃で過を行ない
96重量％の回収率で液を得た。
操作２ この液１部に対して工業用ガソリン
（JIS Ｋ−2201）を1/2部加え、70℃で加熱混合
し、ピツチゾーンで沈降するピツチ状の不溶性相
を回収し、減圧蒸留して、軟化点90℃、キノリン
に不溶の物質0.03％のピツチを得た。
操作３ このピツチを窒素雰囲気で大気圧下、
380℃で８時間加熱処理を行なつたところ、キノ
リン不溶分45％のピツチが得られ、500倍の偏光
顕微鏡で観察したところ直径約５〜10μの光学異
方性球体が視野全面に見られた。この時のピツチ
の軟化点は230℃であつた。又操作１で得られた
液を減圧蒸留して92℃の軟化点を有するピツチ
と操作２で得られた軟化点90℃のピツチをキノリ
ンを移動相とするゲル浸透クロマトグラフイーを
用いて、溶出パターンの比較を行つたところ、操
作１から得られたピツチより操作２より得られた
ピツチの方が大きな分子の比率が高く、分子量分
布も狭く、全体として高い平均分子量を有してい
た。
操作４ 操作２により得られたピツチを330℃
で溶融紡糸したところ１時間にわたつて連続紡糸
が可能であつた。この繊維を210℃で不融化処理
した後、1500℃で炭化処理して炭素繊維を製造し
た。この炭素繊維は平均繊維径15μであり、引張
強度210Kg／mm2、弾性率15t／mm2であつた。
実施例 ２
軟化点31℃、キノリンに不溶の物質を1.5重量
％を含むコールタール１部に、トルエン４部とｎ
−ヘキサン５部を加え、750℃で混合放置した。
クリスタルゾーンで析出した不溶性相は黒色ピツ
チ板状結晶状を呈し、容器底部に沈降した、この
不溶性相を回収し、該不溶性相に対して１部のキ
ノリンを加えて加圧過を行ない、得られた液
を減圧蒸留して、軟化点88℃のキノリンに不溶の
物質が0.02％のピツチを回収した。このピツチを
窒素雰囲気、５mmHgの減圧下350℃で40分間加熱
処理を行なつたところキノリン不溶分３重量％の
ピツチが得られた。このピツチの軟化点は220℃
であつた。このピツチを流動試験機により300〜
350℃の温度範囲で測定したところ極めて均一な
流動を示めした。又このピツチを200倍偏光顕微
鏡で観察したところ視野の全面にわたつて直径約
1μ以下の光学異方性球体の生成が見られた。
該ピツチを溶融紡糸し、不融化処理、及び炭化
工程を経た後2800℃で黒鉛化処理して得た炭素繊
維の引張り強度は260Kg／mm2、弾性率20t／mm2であ
つた。
実施例 ３
軟化点23℃、トルエン不溶分7.9％、キノリン
に不溶の物質2.2％のコールタール軟ピツチ１部
に、芳香族系軽油（JIS K2254による初留点191
℃、乾点328℃）1/6部を70℃で混合撹拌し放冷
後、工業用ガソリン４号（JIS K2201）を1/2部
加え混合した。析出した不溶性相を回収し、過
して、キノリンに不溶の物質0.05％のピツチを得
た。
このピツチを減圧蒸留により軟化点約220℃と
し、これを窒素雰囲気３mmHgの減圧下で390℃、
20分間の加熱処理を行つた。得られたピツチを
200倍の偏光顕微鏡下で観察したところ、メゾフ
エーズはほとんど観察されなかつた。このピツチ
の軟化点は210℃であつた。
該ピツチを実施例２と同じ工程で製造した炭素
繊維の引張り強度は、230Kg／mm2、弾性率17t／mm2
であつた。
実施例 ４
実施例２で得られた軟化点88℃のキノリンに不
溶の物質が0.02重量％のピツチを窒素雰囲気、大
気圧下400℃で２時間加熱処理した。このピツチ
を200倍の偏光顕微鏡で観察したところ１〜5μの
粒径を有する光学異方性球体が全視野の５％を示
めていた。又このピツチのキノリン不溶分を測定
したところ、18重量％であつた。該ピツチを実施
例２と同じ工程で製造した炭素繊維の引張り強度
は200Kg／mm2、弾性率は17t／mm2であつた。
比較例 １
キノリンに不溶の物質1.0wt％、軟化点40℃の
コールタール軟ピツチを溶媒処理することなく、
窒素雰囲気、大気圧下410℃で５時間加熱処理し
たところ、メゾフエーズは小さく、この時のキノ
リン不溶分は30wt％であつた。
このピツチを通常の如く紡糸したところ、糸切
れを生じ連続紡糸が出来なかつた。又紡糸炭素繊
維を実施例１と同様な工程で炭素繊維を製造した
ところ、その引張り強度は、僅か60Kg／mm2であつ
た。
比較例 ２
実施例１で使用したコールタール軟ピツチを用
いて、キノリンに不溶の物質を過で除去した
後、溶媒処理せずに、窒素雰囲気で３mmHgの減
圧下380℃で30時間熱処理を行なつたところ、軟
化点250℃のピツチが得られた。このピツチを200
倍の偏光顕微鏡で観察したところ約１〜200μの
メゾフエーズが存在していた。キノリン不溶分は
30wt％であつた。このピツチは、比較例１と同
じく紡糸性が悪かつた。
以上の如く本発明は原料を脂肪族系溶媒及び芳
香族系溶媒により処理することにより結晶性にす
ぐれ、均質でしかも高い熱可塑性を有するピツチ
を製造することが出来る。このピツチを用いて、
炭素繊維を製造すると、紡糸性が良く、炭素繊維
としてもすぐれた性能を有していた。[Table] By such solvent treatment, the insoluble phase used in the present invention can be recovered very easily. Next, the present invention will be explained in detail. For the aromatic composition, coal tar and/or coal tar pitch is used as a starting material, and when an aromatic solvent and an aliphatic solvent are mixed therein under normal pressure and at room temperature to 250°C, the pitch zone or In the crystal zone an insoluble phase forms. In the present invention, this insoluble substance is used, and 0.1% by weight of the quinoline insoluble substance is used.
When using an insoluble phase from raw materials containing more than
Substances insoluble in quinoline contained in the raw material or in the insoluble phase precipitated in the pitch zone or crystal zone by solvent treatment are removed by means such as filtration or centrifugation. The coal tar used in the present invention is produced during high-temperature carbonization of coal, and the coal tar pitch is obtained by distilling this to remove light oil components. The aromatic solvent used in the present invention is not limited in any way as long as the constituent component is an aromatic hydrocarbon such as benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, or a mixture thereof. Relatively heavy oils such as creosote oil, anthracene oil, or delayed coker by-product oil obtained by coal tar distillation are preferred. On the other hand, even in aliphatic solvents, n-
There are no limitations at all as long as the constituent components are aliphatic hydrocarbons, such as hexane, naphtha, kerosene, diesel fuel oil, and heavy fuel oil. For recovery of the insoluble phase in the separation zone,
Static separation, hydrocyclone, filtration, centrifugation, etc., or a combination thereof can be used. The insoluble phase used in the present invention itself has a higher average molecular weight and a relatively sharp molecular weight distribution than the raw material before solvent treatment. Furthermore, in order to enhance these properties, in the present invention, the normal pressure or reduced pressure distillation operation is appropriately adjusted to obtain a higher average molecular weight and a sharper molecular weight distribution depending on the required use. The insoluble phase prepared in this way is
The heat treatment is carried out at a temperature of 500°C, preferably in the range of 300°C to 450°C, and since the molecular weights are uniform as described above, a homogeneous mesophase is formed in a relatively short time by this heating. When the heating temperature is 500℃ or higher,
Since the rate of crystallization is too fast to control the degree of progress of crystallization, it cannot be said to be very suitable. A heating temperature of 250℃ or less is acceptable, but
It takes too much time to form mesophase, which is an easily graphitizable component. The heating time at this temperature is the time until the pitch produced according to the present invention exhibits fluidity even at a temperature of 200°C to 400°C as measured with a flow tester. The heating time is about 10 minutes to 5 hours, depending on the heating temperature. To adjust the particle size of the mesophase, the heating temperature and time are controlled. For example, about 250℃~380℃
If the treatment is carried out at such a low temperature for a long time, a large amount of small-diameter mesophases will be produced. Furthermore, if the processing temperature is increased, the mesophase will be formed faster, resulting in a large-diameter mesophase. In either case, the heating time can be shortened by concentrating the raw material pitch which has been subjected to distillation and solvent treatment in advance. When the pitches produced in this manner are observed with a polarizing microscope, it is found that they contain mesophases that are uniformly sized and have optical anisotropy. By adjusting the heating temperature and heating time in this manner, the particle size and thermoplasticity of mesophase can be freely controlled according to each application. As for the pitch for carbon fiber used in the present invention, it is preferable that the mesophase is not too large. The mesophase in the pitch used in the present invention is preferably such that the mesophase cannot be confirmed under 200x magnification using a polarizing microscope, or the presence of the mesophase can be confirmed for the first time. In other words, if the diameter of the mesophase present in the pitch is larger than the diameter of the spun fiber, knots or voids will form in the part during spinning of the fiber, making continuous spinning impossible, and furthermore, the tensile strength will be low even when fired as a carbon fiber. This is because the carbon fiber becomes weak and cannot exhibit its original performance. The pitch produced by the method of the present invention is melted at a temperature in the range of 250 to 400°C, extruded through a nozzle, and spun. Thereafter, the spun fibers are infusible at 200-300°C as usual, and then heated at 1000-300°C in an inert gas phase.
Carbonization is carried out at 1500℃, and if necessary, graphitization is further carried out at 2000℃ or higher to produce carbon fibers. The carbon fibers produced according to the present invention can be made into general-purpose or high-quality carbon fibers by appropriately selecting the temperatures in the carbonization and graphitization steps. The method for producing carbon fibers of the present invention is characterized by the preparation of raw materials for carbon fibers, and it aims to homogenize the raw materials by treating the raw materials with a solvent and making the molecular weight distribution as uniform as possible. The manufactured carbon fiber has high strength and can be manufactured with uniform quality. Next, the present invention will be explained using examples. Example 1 Procedure 1 A substance insoluble in quinoline with a softening point of 25°C
Aromatic light oil (initial boiling point 191℃ according to JIS K-2254,
Add 1/5 part of dry point 328℃) and heat at 120℃.
A liquid was obtained with a recovery rate of 96% by weight. Step 2 Add 1/2 part of industrial gasoline (JIS K-2201) to 1 part of this liquid, heat and mix at 70°C, collect the pitch-like insoluble phase that settles in the pitch zone, and distill it under reduced pressure. Pitch with a softening point of 90°C and a substance insoluble in quinoline of 0.03% was obtained. Step 3 Place this pitch in a nitrogen atmosphere under atmospheric pressure.
After heat treatment at 380℃ for 8 hours, pitches with 45% quinoline insoluble content were obtained, and when observed with a polarizing microscope at 500x magnification, optically anisotropic spheres with a diameter of approximately 5 to 10μ were seen over the entire field of view. Ta. The softening point of pitch at this time was 230°C. In addition, using gel permeation chromatography using quinoline as a mobile phase, the pitch obtained in Step 1 was distilled under reduced pressure to have a softening point of 92°C, and the pitch obtained in Step 2 had a softening point of 90°C. Comparison of the elution patterns revealed that the pitch obtained from Operation 2 had a higher proportion of large molecules than the pitch obtained from Operation 1, had a narrower molecular weight distribution, and had a higher average molecular weight overall. Step 4 Heat the pitch obtained in Step 2 to 330℃
When melt spinning was carried out, continuous spinning was possible for one hour. This fiber was treated to be infusible at 210°C and then carbonized at 1500°C to produce carbon fiber. This carbon fiber had an average fiber diameter of 15 μm, a tensile strength of 210 Kg/mm 2 , and an elastic modulus of 15 t/mm 2 . Example 2 To 1 part of coal tar containing 1.5% by weight of a substance insoluble in quinoline with a softening point of 31°C, 4 parts of toluene and n
- 5 parts of hexane were added and the mixture was left to mix at 750°C.
The insoluble phase precipitated in the crystal zone was in the form of black pitch plate crystals, and the insoluble phase settled at the bottom of the container was collected, and 1 part of quinoline was added to the insoluble phase and pressure was applied. The resulting liquid was distilled under reduced pressure to recover pitch, which had a softening point of 88°C and contained 0.02% of substances insoluble in quinoline. This pitch was heat-treated at 350° C. for 40 minutes under a reduced pressure of 5 mmHg in a nitrogen atmosphere, and a pitch containing 3% by weight of quinoline insolubles was obtained. The softening point of this pitch is 220℃
It was hot. This pitch is tested using a flow tester to
Measurements over a temperature range of 350°C showed extremely uniform flow. Also, when this pitch was observed with a 200x polarizing microscope, it was found that the diameter was approximately
The formation of optically anisotropic spheres with a diameter of 1μ or less was observed. The pitch was melt-spun, subjected to an infusibility treatment and a carbonization step, and then graphitized at 2800° C. The resulting carbon fiber had a tensile strength of 260 Kg/mm 2 and an elastic modulus of 20 t/mm 2 . Example 3 One part of soft coal tar with a softening point of 23°C, 7.9% of toluene-insoluble matter, and 2.2% of substances insoluble in quinoline was added to aromatic light oil (initial boiling point of 191 according to JIS K2254).
℃, dry point 328℃) were mixed and stirred at 70℃, and after cooling, 1/2 part of industrial gasoline No. 4 (JIS K2201) was added and mixed. The precipitated insoluble phase was collected and filtered to obtain a pitch containing 0.05% of the material insoluble in quinoline. This pitch was distilled under reduced pressure to a softening point of approximately 220°C, and then heated to 390°C under a reduced pressure of 3 mmHg in a nitrogen atmosphere.
Heat treatment was performed for 20 minutes. The resulting pitch
When observed under a polarizing microscope at 200x magnification, almost no mesophase was observed. The softening point of this pitch was 210°C. The tensile strength of the carbon fiber produced from the pitch in the same process as in Example 2 is 230 Kg/mm 2 , and the elastic modulus is 17 t/mm 2
It was hot. Example 4 Pitch containing 0.02% by weight of a substance insoluble in quinoline and having a softening point of 88°C obtained in Example 2 was heat treated at 400°C under atmospheric pressure in a nitrogen atmosphere for 2 hours. When this pitch was observed under a polarizing microscope with a magnification of 200 times, optically anisotropic spheres having a particle size of 1 to 5 microns occupied 5% of the entire field of view. When the quinoline insoluble content of this pitch was measured, it was 18% by weight. The pitch was manufactured using the same process as in Example 2. The carbon fiber had a tensile strength of 200 Kg/mm 2 and an elastic modulus of 17 t/mm 2 . Comparative Example 1 A coal tar soft pitch containing 1.0 wt% of a substance insoluble in quinoline and a softening point of 40°C was prepared without solvent treatment.
When heat treated at 410° C. in a nitrogen atmosphere and atmospheric pressure for 5 hours, mesophase was small and the quinoline insoluble content was 30 wt%. When this pitch was spun as usual, thread breakage occurred and continuous spinning was not possible. Further, when spun carbon fibers were manufactured using the same process as in Example 1, the tensile strength was only 60 Kg/mm 2 . Comparative Example 2 Using the coal tar soft pitch used in Example 1, substances insoluble in quinoline were removed by filtration, and then heat treatment was performed at 380°C under a reduced pressure of 3 mmHg in a nitrogen atmosphere for 30 hours without solvent treatment. When it was warmed up, pitch was obtained with a softening point of 250°C. This pitch is 200
When observed under a polarizing microscope with a magnification of 1:1, mesophases of approximately 1 to 200 μm were present. The quinoline insoluble content is
It was 30wt%. This pitch had poor spinnability as in Comparative Example 1. As described above, in the present invention, by treating raw materials with an aliphatic solvent and an aromatic solvent, it is possible to produce a pitch having excellent crystallinity, homogeneity, and high thermoplasticity. Using this pitch,
When carbon fibers were produced, they had good spinnability and excellent performance as carbon fibers.
第１図は、芳香族系組成物に対する溶媒の混合
比率と不溶性相の析出状態を示す。
FIG. 1 shows the mixing ratio of the solvent to the aromatic composition and the state of precipitation of the insoluble phase.
Claims (1)
ばれた芳香族組成物に、芳香族系溶媒と脂肪族系
溶媒とを混合し、ピツチゾーン又はクリスタルゾ
ーンから析出する不溶性相を回収し、これに含有
するキノリン不溶の物質を除去したのち、該回収
物を常圧又は減圧下で蒸留して低沸点留分を除去
して得られたピツチを加熱処理し、次いで溶融紡
糸し、不融化し、更に焼成することを特徴とする
炭素繊維の製造方法。1. Mix an aromatic solvent and an aliphatic solvent with an aromatic composition selected from coal tar or coal tar pitch, collect the insoluble phase precipitated from the pitch zone or crystal zone, and remove the quinoline insoluble phase contained therein. After removing the substances, the recovered material is distilled under normal pressure or reduced pressure to remove low-boiling fractions, and the resulting pitch is heat-treated, then melt-spun, made infusible, and further calcined. A method for producing carbon fiber characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4004082A JPS58156027A (en) | 1982-03-13 | 1982-03-13 | Preparation of carbon fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4004082A JPS58156027A (en) | 1982-03-13 | 1982-03-13 | Preparation of carbon fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58156027A JPS58156027A (en) | 1983-09-16 |
| JPH0229765B2 true JPH0229765B2 (en) | 1990-07-02 |
Family
ID=12569793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4004082A Granted JPS58156027A (en) | 1982-03-13 | 1982-03-13 | Preparation of carbon fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58156027A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61108725A (en) * | 1984-10-30 | 1986-05-27 | Teijin Ltd | Production of pitch carbon yarn having novel structure |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54160427A (en) * | 1977-07-08 | 1979-12-19 | Exxon Research Engineering Co | Production of optically anisotropic* deformable pitch* optical anisotropic pitch* and pitch fiber |
| JPS5558287A (en) * | 1978-05-05 | 1980-04-30 | Exxon Research Engineering Co | Improvement in forming neomesophase |
| JPS55157652A (en) * | 1980-02-29 | 1980-12-08 | Pioneer Electronic Corp | Molding composition |
| JPS5747384A (en) * | 1980-09-03 | 1982-03-18 | Nippon Steel Chem Co Ltd | Preparation of pitch |
-
1982
- 1982-03-13 JP JP4004082A patent/JPS58156027A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54160427A (en) * | 1977-07-08 | 1979-12-19 | Exxon Research Engineering Co | Production of optically anisotropic* deformable pitch* optical anisotropic pitch* and pitch fiber |
| JPS5558287A (en) * | 1978-05-05 | 1980-04-30 | Exxon Research Engineering Co | Improvement in forming neomesophase |
| JPS55157652A (en) * | 1980-02-29 | 1980-12-08 | Pioneer Electronic Corp | Molding composition |
| JPS5747384A (en) * | 1980-09-03 | 1982-03-18 | Nippon Steel Chem Co Ltd | Preparation of pitch |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58156027A (en) | 1983-09-16 |
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