JPH0144753B2 - - Google Patents
Info
- Publication number
- JPH0144753B2 JPH0144753B2 JP11633281A JP11633281A JPH0144753B2 JP H0144753 B2 JPH0144753 B2 JP H0144753B2 JP 11633281 A JP11633281 A JP 11633281A JP 11633281 A JP11633281 A JP 11633281A JP H0144753 B2 JPH0144753 B2 JP H0144753B2
- Authority
- JP
- Japan
- Prior art keywords
- pitch
- raw material
- heavy oil
- petroleum
- spinning
- 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
Links
- 239000002994 raw material Substances 0.000 claims description 38
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 29
- 239000004917 carbon fiber Substances 0.000 claims description 29
- 239000000295 fuel oil Substances 0.000 claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 19
- 239000003208 petroleum Substances 0.000 claims description 16
- 239000002243 precursor Substances 0.000 claims description 16
- 238000003763 carbonization Methods 0.000 claims description 14
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 13
- 238000011282 treatment Methods 0.000 claims description 13
- 238000009835 boiling Methods 0.000 claims description 12
- 238000002074 melt spinning Methods 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000005087 graphitization Methods 0.000 claims description 7
- 239000001257 hydrogen Substances 0.000 claims description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 6
- 238000004231 fluid catalytic cracking Methods 0.000 claims description 6
- 238000000354 decomposition reaction Methods 0.000 claims 1
- 239000011295 pitch Substances 0.000 description 73
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 29
- 239000003054 catalyst Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 208000012886 Vertigo Diseases 0.000 description 7
- 239000007789 gas Substances 0.000 description 7
- 238000009987 spinning Methods 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000003921 oil Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000002411 adverse Effects 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000004939 coking Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000004973 liquid crystal related substance Substances 0.000 description 3
- 239000011302 mesophase pitch Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 229920002239 polyacrylonitrile Polymers 0.000 description 3
- 238000009423 ventilation Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 125000003118 aryl group Chemical group 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000011294 coal tar pitch Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003350 kerosene Substances 0.000 description 2
- 239000012263 liquid product Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000004230 steam cracking Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000007380 fibre production Methods 0.000 description 1
- 239000003502 gasoline Substances 0.000 description 1
- 229910052811 halogen oxide Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- -1 naphtha Substances 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000011301 petroleum pitch Substances 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 150000003248 quinolines Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000011318 synthetic pitch Substances 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Landscapes
- Working-Up Tar And Pitch (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Inorganic Fibers (AREA)
Description
本発明は炭素繊維製造用原料としての優れた性
能を有するピツチの製造方法に関する。
現在、炭素繊維は主にポリアクリロニトリルを
原料として製造されている。しかしながらポリア
クリロニトリルを原料とした場合、原料が高価で
あり、また加熱炭化時において繊維状の原形がく
ずれ易く、さらに炭化収率も悪いという欠点があ
る。
近年、この点に着目してピツチを原料として炭
素繊維を製造する方法が数多く報告されている。
ピツチを原料として用いた場合、原料が安価であ
り、また炭化収率が通常85〜95%と高いため、安
価に炭素繊維を製造できることが期待される。し
かしながら、ピツチを原料として得られる炭素繊
維は、ポリアクリロニトリル系炭素繊維に比べ、
弾性率は高いものの、強度が劣るという問題があ
る。従つて、もしこの問題点を解決し、また弾性
率をさらに向上し得ることができれば、ピツチか
ら安価に高強度かつ高弾性率の炭素繊維を製造す
ることが可能となる。
最近になつて、市販の石油ピツチを熱処理し
て、メソ相(mesophase)と呼ばれる光学的異方
性の液晶を含有するピツチを得、このメソ相を含
有するピツチを前駆体ピツチ(以後、溶融紡糸時
におけるピツチを前駆体ピツチと呼ぶ)として用
い、この前駆体ピツチを溶融紡糸した後、不融化
し、次いで炭化あるいは更に黒鉛化することによ
り、弾性率および強度が向上した炭素繊維が得ら
れることが報告された(特開昭49−19127号)。
しかしながらピツチが液晶を形成し得るか否か
は種々の要因により決まるものであり、また液晶
の構造や軟化点、粘度等の物性は原料ピツチに大
きく依存するものである。前記特開昭49−19127
号はメソ相を含有するピツチ(以後メソ相ピツチ
と略記する)の調製法に関するものであつて、良
質のメソ相ピツチを形成するための原料ピツチに
ついては何ら言及していない。前記したように、
良質のメソ相ピツチは原料ピツチに大きく依存す
るものであり、最適な原料ピツチを見出すことが
できれば弾性率および強度がさらに優れた炭素繊
維を製造することが可能となる。それ故、この最
適の原料ピツチを見出すことが当該技術分野の重
要な課題である。
例えば、コールタールピツチはカーボンブラツ
ク状のキノリンに不溶で不融性の物質を含有して
おり、これらは前駆体ピツチの不均一性の原因と
なり紡糸性を悪くさせるばかりか、炭素繊維の強
度および弾性率に悪影響を及ぼす。
一方、市販の石油ピツチやその他の合成ピツチ
の多くは、キノリンに不溶で不融性の物質をほと
んど含有していないが、これらのピツチを加熱処
理して前駆体ピツチを調製する段階で、キノリン
に不溶な高分子量成分が生成する。すなわち、こ
れらのピツチを熱処理すると熱分解と重縮合反応
が併発し、低分子量成分は徐々に高分子量化し、
キノリンに不溶の高分子量成分となり、また同時
に高分子量成分はさらに高分子量化する。これに
伴つてピツチの軟化点も上昇する。このキノリン
不溶分がコールタール中のカーボンブラツク状物
質に類似の物質であれば、前述の如く紡糸以降の
工程で悪影響を及ぼす。また、前記のカーボンブ
ラツク状物質とは異なる物質であつたとしても、
多量のキノリン不溶分の存在と高い軟化点は溶融
紡糸の段階で悪影響を及ぼす。すなわち、前駆体
ピツチを溶融紡糸するためには、前駆体ピツチが
紡糸可能な粘度になるまで紡糸温度を上げること
が必要であつて、前駆体ピツチの軟化点が余りに
も高過ぎれば、紡糸温度も当然高くせざるを得
ず、その結果、キノリン不溶分は一層高分子量化
すると共に、ピツチの熱分解が起こり軽質ガスが
発生し、均一な前駆体ピツチとはなり得ず、紡糸
することが事実上不可能となる。
このように前駆体ピツチは、比較的低い軟化点
と紡糸するために適当な粘度を持つていなければ
ならない。また、紡糸時さらには炭化時に揮発性
成分を実質的に含有するものであつてはならな
い。
このため、生成したキノリン不溶分を加圧過
や溶剤分別等の手段により除去することにより炭
素繊維製造用前駆体ピツチを調製することが行わ
れている(特開昭47−9804号、同50−142820号、
同55−1342号、同55−5954号)。しかしながら、
これらの手段を用いた場合には処理装置の複雑化
および処理費用の増大を招き、経済的観点から好
ましいものではない。
もし、原料ピツチとして優れた性能を有するピ
ツチを用いることにより、メソ相化の加熱段階で
キノリン不溶分となる高分子量成分を生成させな
いことができれば、最も好ましいものである。
本発明者らは、これらの課題について鋭意研究
した結果、本発明を完成したものである。すなわ
ち、本発明者らは、前駆体ピツチを調製する段階
で高分子量成分の生成を抑制し、最適な粘度を有
し、また炭化初期の段階では芳香族平面が秩序だ
つて配列をし易い組成を持つことができる性能の
優れた原料ピツチを見出したものである。換言す
れば、本発明は軟化点が比較的低く保持され、か
つメソ相を容易に形成するような原料ピツチの製
造方法を提供するものである。
すなわち、本発明は原料ピツチを加熱処理して
得られる前駆体ピツチを溶融紡糸した後、不融化
処理および炭化あるいは更に黒鉛化処理して炭素
繊維を製造するに当たり、該原料ピツチが(1)石油
類を水蒸気分解した際に得られる沸点200℃以上
の重質油と(2)石油類を流動接触分解した際に得ら
れる沸点200℃以上の重質油との混合物を20Kg/
cm2・G以上の水素加圧下で、温度400〜500℃で熱
処理することにより得られるものであることを特
徴とする炭素繊維用原料ピツチの製造方法に関
し、本発明により得られる原料ピツチを用いるこ
とにより高弾性率で、かつ高強度の炭素繊維が得
られる。
一方、重質油を水素存在下に熱処理して原料ピ
ツチを製造する方法として、特公昭45−28013号
の方法が知られている。しかしながら、特公昭45
−28013号の方法は触媒の存在下に重質油の水素
化を行うもので、触媒の使用に伴う触媒分離等の
操作の繁雑さや、触媒コストが高いなどの経済性
の面での不利益が避け難い。また得られる炭素繊
維も必ずしも高弾性率および高強度のものとは言
い難い。
本発明者らは、詳細に検討を行つた結果、高弾
性率かつ高強度の炭素繊維の原料としての最適な
ピツチは特定の重質油をきわめて限られた熱処理
条件下に水素化触媒を用いることなく行わねばな
らないことを見出したものである。すなわち、(1)
石油類を水蒸気分解した際に得られる沸点200℃
以上の重質油と(2)石油類を流動接触分解した際に
得られる沸点200℃以上の重質油との混合物を20
Kg/cm2・G以上の水素加圧下で、温度400〜500℃
で熱処理して得られる本発明よりなる原料ピツチ
を用いて、メソ相化反応を行わしめた場合、キノ
リン不溶分の生成が抑制されるばかりかピツチが
改質され、最終製品である炭素繊維が一層高弾性
率でかつ高強度となり得たことは全く予期され得
ないものであつた。
これに対し、コールタールピツチ、市販の石油
ピツチあるいは合成ピツチを特開昭49−19127号
の方法に従つて加熱処理し、メソ相化を行つたと
ころ、生成ピツチの軟化点が340℃以上のもの、
固形物が沈積したもの、あるいは固形物が沈積し
ないまでもキノリン不溶分が70wt%以上に達し
たもの等、多くの場合、溶融紡糸が事実上不可能
であつた。また溶融紡糸を行い得た場合でも、さ
らに不融化、炭化および黒鉛化処理して得た炭素
繊維の強度は120〜200Kg/ml、弾性率は12〜
20ton/mm2程度であつた。また高軟化点のものを
紡糸した場合には、紡糸物中に熱分解ガス発生に
起因する空孔が存在していた。
以下本発明を詳述する。
本発明において用いられる石油類を水蒸気分解
した際に得られる沸点200℃以上の重質油とは、
ナフサ、灯油あるいは軽油等の石油類を通常700
〜1200℃で水蒸気分解して、エチレン、プロピレ
ン等のオレフイン類を製造する際に副生する重質
油であつて実質的に沸点が200〜450℃の範囲内の
重質油である。
本発明において用いられる石油類を流動接触分
解した際に得られる沸点200℃以上の重質油とは、
灯油、軽油あるいは常圧残油等の石油類を天然あ
るいは合成のシリカ・アルミナ触媒あるいはゼオ
ライト触媒の存在下に450〜550℃、常圧〜20Kg/
cm2・Gにて流動接触分解することにより、ガソリ
ン等の軽質油を製造する際に副生する重質油であ
つて実質的に沸点が200〜450℃の範囲内の重質油
である。
本発明の原料ピツチの製造方法は、(1)石油類を
水蒸気分解した際に得られる沸点200℃以上の重
質油と(2)石油類を流動接触分解した際に得られる
沸点200℃以上の重質油との混合物を20Kg/cm2・
G以上、例えば20〜350Kg/cm2・G、好ましくは
50〜300Kg/cm2・Gの水素加圧下で、温度400〜
500℃、好ましくは405〜450℃で熱処理すること
により得られる。
上記の成分(1)と成分(2)の混合割合は、成分(1):
成分(2)が重量比で1:0.1〜9好ましくは1:0.2
〜4である。
熱処理温度が400℃よりも低いと、得られるピ
ツチはメソ相化を行つた際、キノリン不溶分が多
量に生成するため溶融紡糸過程でのコーキング、
相分離、軟化点上昇等のトラブルが生じ易く、さ
らのに得られる炭素繊維の性能も劣り好ましくな
い。また熱処理温度が500℃よりも高いと、原料
ピツチ製造の段階でコーキング等の問題が生じ、
実質上、原料ピツチ製造が困難となる。
熱処理を行つた後、必要であれば蒸留等の操作
により軽質分を除去することも好ましく採用され
る。
かくして得られる本発明よりなる原料ピツチを
用いることにより、加熱処理してメソ相化を行つ
た際、キノリン不溶分である高分子量成分の生成
が抑制されると同時にピツチの軟化点の上昇を防
ぐことができ、さらに芳香族平面が秩序だつて配
列し易い組成を持つた良好な前駆体ピツチとな
る。この結果、弾性率および強度がきわめて優れ
た炭素繊維を得ることができる。
本発明により得られる原料ピツチを用いて炭素
繊維を製造する方法は公知の方法を採用すること
ができる。すなわち、原料ピツチを加熱処理して
メソ相化を行い、得られる前駆体ピツチを溶融紡
糸した後、不融化処理および炭化あるいはさらに
黒鉛化処理を行つて炭素繊維を製造する。
原料ピツチを加熱処理し、メソ相化を行つて前
駆体ピツチを得る段階での反応は、通常、温度
340〜450℃、好ましくは370〜420℃で、常圧ある
いは減圧下に窒素等の不活性ガスを通気すること
によつて行われる。この時の加熱処理時間は、温
度、不活性ガスの通気量等の条件により任意に行
い得るものであるが、通常、1〜50時間、好まし
くは3〜20時間で行う。不活性ガスの通気量は
0.7〜5.0scfh/1bピツチが好ましい。
前駆体ピツチを溶融紡糸する方法としては、押
出法、遠心法、霧吹法等の公知の方法を用いるこ
とができる。
溶融紡糸されて得られるピツチ繊維は、次に酸
化性ガス雰囲気下で不融化処理が施される。酸化
性ガスとしては、通常、酸素、オゾン、空気、窒
素酸化物、ハロゲン、亜硫酸ガス等の酸化性ガス
を1種あるいは2種以上用いる。この不融化処理
は、被処理体である溶融紡糸されたピツチ繊維が
軟化変形しない温度条件下で実施される。例えば
20〜360℃、好ましくは20〜300℃の温度が採用さ
れる。また処理時間は通常、5分〜10時間であ
る。
不融化処理されたピツチ繊維は、次に不活性ガ
ス雰囲気下で炭化あるいは更に黒鉛化を行い、炭
素繊維を得る。炭化は通常、温度800〜2500℃で
行う、一般には炭化に要する処理時間は0.5分〜
10時間である。さらに黒鉛化を行う場合には、温
度2500〜3500℃で、通常1秒〜1時間行う。
また、不融化、炭化あるいは黒鉛化処理の際、
必要であれば収縮や変形等を防止する目的で、被
処理体に若干の荷重あるいは張力をかけておくこ
ともできる。
以下に実施例をあげ本発明を具体的に説明する
が、本発明はこれらに制限されるものではない。
実施例 1
ナフサを830℃で水蒸気分解した際に副生した
沸点200℃以上の重質油(以下、重質油(1)と略す。
その性状を第1表に示す)100gとアラビア系原
油の減圧軽油(VGO)の水素化処理油をシリ
カ・アルミナ系触媒を用いて500℃にて接触分解
して得られた沸点200℃以上の重質油(以下、重
質油(2)と略す。その性状を第2表に示す)50gと
の混合物を内容積300mlの撹拌機付きオートクレ
ーブ中で水素初圧100Kg/cm2・Gで、昇温速度3
℃/分にて435℃まで加熱し、435℃で2.5時間保
持した。しかる後、加熱を停止し、室温まで冷却
した。得られた液状生成物を250℃/1mmHgで蒸
留して軽質分を留出させ原料ピツチを得た。この
ピツチの軟化点は63℃、キノリン不溶分は0%で
あり、収率は35wt%であつた。
次に、この原料ピツチ30gに対し、窒素を600
ml/分で通気しながら撹拌し、温度400℃で10時
間熱処理を行い、軟化点268℃、キノリン不溶分
27wt%、メソ相含量88%のピツチを、47%の収
率で得た。このピツチをノズル径0.3mmφ、L/
D=2の紡糸器を用い320℃で溶融紡糸し、11〜
15μのピツチ繊維をつくり、さらに下記に示す条
件にて不融化、炭化および黒鉛化処理して炭素繊
維を得た。
Γ不融化条件:空気雰囲気中で、200℃までは3
℃/分、300℃までは1℃/分の昇温速度で加
熱し、300℃で15分間保持。
Γ炭化条件:窒素雰囲気中で、5℃/分で昇温し
1000℃で30分間保持。
Γ黒鉛化条件:アルゴン気流中で、25℃/分の昇
温速度で、2500℃まで加熱処理。
得られた炭素繊維の引張強度は285Kg/mm2、ヤ
ング率は47ton/mm2であつた。
本発明の原料ピツチを用いて得られる炭素繊維
は、比較例1で示すように代表的な市販の石油ピ
ツチであるアツシユランド(Ashland)240を原
料ピツチとして用いた場合に比べ、高強度で、か
つ高弾性率であることが明らかである。
The present invention relates to a method for producing pitch, which has excellent performance as a raw material for producing carbon fibers. Currently, carbon fiber is mainly manufactured using polyacrylonitrile as a raw material. However, when polyacrylonitrile is used as a raw material, there are disadvantages in that the raw material is expensive, the original fibrous shape is easily destroyed during heating and carbonization, and the carbonization yield is also poor. In recent years, focusing on this point, many methods have been reported for producing carbon fibers using pitch as a raw material.
When pitch is used as a raw material, it is expected that carbon fibers can be produced at low cost because the raw material is inexpensive and the carbonization yield is usually as high as 85 to 95%. However, compared to polyacrylonitrile-based carbon fiber, carbon fiber obtained from pitch is
Although it has a high elastic modulus, it has a problem of poor strength. Therefore, if this problem could be solved and the modulus of elasticity could be further improved, it would be possible to produce carbon fibers with high strength and high modulus at low cost from pitch. Recently, commercially available petroleum pits have been heat-treated to obtain pitches containing optically anisotropic liquid crystals called mesophases, and pitches containing this mesophases have been converted into precursor pits (hereinafter referred to as molten). Carbon fibers with improved elastic modulus and strength can be obtained by melt-spinning this precursor pitch, making it infusible, and then carbonizing or graphitizing it. It was reported (Japanese Unexamined Patent Publication No. 19127-1983). However, whether a pitch can form a liquid crystal is determined by various factors, and the structure, softening point, viscosity, and other physical properties of the liquid crystal greatly depend on the raw material pitch. Said Japanese Unexamined Patent Publication No. 49-19127
This issue relates to a method for preparing pitch containing mesophase (hereinafter abbreviated as mesophase pitch), but does not mention anything about the raw material pitch for forming high quality mesophase pitch. As mentioned above,
A high-quality mesophase pitch largely depends on the raw material pitch, and if an optimal raw material pitch can be found, it will be possible to produce carbon fibers with even better elastic modulus and strength. Therefore, finding this optimal raw material pitch is an important challenge in this technical field. For example, coal tar pitch contains substances that are insoluble and infusible in carbon black-like quinoline, and these not only cause non-uniformity of the precursor pitch and deteriorate spinnability, but also reduce the strength and strength of carbon fibers. Adversely affects elastic modulus. On the other hand, many commercially available petroleum pitches and other synthetic pitches contain almost no substances that are insoluble and infusible in quinoline. Insoluble high molecular weight components are produced. In other words, when these pitches are heat-treated, thermal decomposition and polycondensation reactions occur simultaneously, and the low molecular weight components gradually become high molecular weight.
It becomes a high molecular weight component that is insoluble in quinoline, and at the same time, the high molecular weight component further increases in molecular weight. Along with this, the softening point of pitch also increases. If this quinoline insoluble matter is similar to the carbon black-like substance in coal tar, it will have an adverse effect on the steps after spinning as described above. Furthermore, even if the substance is different from the carbon black-like substance mentioned above,
The presence of a large amount of quinoline insolubles and a high softening point have an adverse effect on the melt spinning stage. In other words, in order to melt-spun a precursor pitch, it is necessary to raise the spinning temperature until the precursor pitch has a viscosity that allows spinning, and if the softening point of the precursor pitch is too high, the spinning temperature may As a result, the molecular weight of the insoluble portion of quinoline becomes even higher, and the pitch is thermally decomposed and light gas is generated, making it impossible to form a uniform precursor pitch and making it difficult to spin. It becomes virtually impossible. Thus, the precursor pitch must have a relatively low softening point and a suitable viscosity for spinning. Furthermore, it must not substantially contain volatile components during spinning or carbonization. For this reason, precursor pitch for carbon fiber production is prepared by removing the generated quinoline insoluble matter by means such as pressurization and solvent separation (Japanese Patent Application Laid-Open No. 47-9804, 50 −142820,
55-1342, 55-5954). however,
When these means are used, the processing equipment becomes complicated and the processing cost increases, which is not preferable from an economic point of view. It would be most preferable if a pitch having excellent performance could be used as the raw material pitch to prevent the formation of high molecular weight components that would be insoluble in quinoline during the heating step of mesophase formation. The present inventors have completed the present invention as a result of intensive research into these problems. That is, the present inventors suppressed the formation of high molecular weight components at the stage of preparing the precursor pitch, had an optimal viscosity, and created a composition in which the aromatic planes were easily arranged in an orderly manner at the early stage of carbonization. We have discovered a raw material pitch with excellent performance. In other words, the present invention provides a method for producing a raw material pitch in which the softening point is kept relatively low and the mesophase is easily formed. That is, in the present invention, in producing carbon fiber by melt-spinning a precursor pitch obtained by heating a raw material pitch, and then subjecting it to infusibility treatment and carbonization or further graphitization treatment, the raw material pitch is (1) petroleum A mixture of (2) heavy oil with a boiling point of 200°C or more obtained when hydrocatalytic cracking of petroleum and (2) heavy oil with a boiling point of 200°C or more obtained when petroleum is subjected to fluid catalytic cracking.
Regarding a method for producing a raw material pitch for carbon fiber, which is obtained by heat treatment at a temperature of 400 to 500°C under hydrogen pressure of cm 2 G or more, the raw material pitch obtained according to the present invention is used. As a result, carbon fibers with high elastic modulus and high strength can be obtained. On the other hand, as a method for producing raw material pitch by heat-treating heavy oil in the presence of hydrogen, the method disclosed in Japanese Patent Publication No. 45-28013 is known. However,
The method of No. 28013 hydrogenates heavy oil in the presence of a catalyst, and it has disadvantages in terms of economy, such as the complexity of operations such as catalyst separation associated with the use of a catalyst, and the high cost of the catalyst. is difficult to avoid. Furthermore, the obtained carbon fibers cannot necessarily be said to have high elastic modulus and high strength. As a result of detailed studies, the present inventors found that the optimal pitch as a raw material for carbon fiber with high elastic modulus and high strength is to use a specific heavy oil under extremely limited heat treatment conditions using a hydrogenation catalyst. I discovered that I had to do it without any problems. That is, (1)
Boiling point of 200°C obtained when petroleum is steam decomposed
A mixture of the above heavy oils and (2) heavy oil with a boiling point of 200℃ or higher obtained when fluid catalytic cracking of petroleum is
Under hydrogen pressure of Kg/ cm2・G or more, at a temperature of 400 to 500℃
When a mesophase reaction is carried out using the raw material pitch of the present invention obtained by heat treatment with It was completely unexpected that a higher modulus of elasticity and higher strength could be achieved. On the other hand, when coal tar pitch, commercially available petroleum pitch, or synthetic pitch was heat-treated to form a mesophase according to the method of JP-A-49-19127, the resulting pitch had a softening point of 340°C or higher. thing,
In many cases, melt spinning was virtually impossible, such as in cases where solids were deposited, or even if solids were not deposited, the quinoline insoluble content reached 70 wt% or more. Even if melt spinning is possible, the strength of the carbon fiber obtained by further infusibility, carbonization, and graphitization is 120 to 200 Kg/ml, and the elastic modulus is 12 to 200 kg/ml.
It was around 20ton/mm2. Furthermore, when a material with a high softening point was spun, pores were present in the spun material due to the generation of thermal decomposition gas. The present invention will be explained in detail below. The heavy oil with a boiling point of 200°C or higher obtained by steam cracking petroleum used in the present invention is:
Usually 700% of petroleum such as naphtha, kerosene or light oil
It is a heavy oil that is produced by steam cracking at ~1200°C to produce olefins such as ethylene and propylene, and has a boiling point substantially within the range of 200~450°C. The heavy oil with a boiling point of 200°C or higher obtained by fluid catalytic cracking of petroleum used in the present invention is:
Petroleum such as kerosene, light oil or atmospheric residual oil is heated at 450 to 550℃ and at normal pressure to 20 kg/kg in the presence of a natural or synthetic silica/alumina catalyst or zeolite catalyst.
It is a heavy oil that is produced as a by-product when producing light oil such as gasoline by fluid catalytic cracking at cm 2 G, and it is a heavy oil with a substantially boiling point within the range of 200 to 450℃. . The method for producing the raw material pitch of the present invention consists of (1) heavy oil with a boiling point of 200°C or higher obtained when petroleum is steam cracked and (2) a boiling point of 200°C or higher obtained when petroleum is subjected to fluid catalytic cracking. of heavy oil at 20Kg/ cm2・
G or more, for example 20-350Kg/ cm2・G, preferably
Under hydrogen pressure of 50-300Kg/ cm2・G, temperature 400-
It is obtained by heat treatment at 500°C, preferably 405-450°C. The mixing ratio of component (1) and component (2) above is component (1):
Component (2) in a weight ratio of 1:0.1 to 9, preferably 1:0.2
~4. If the heat treatment temperature is lower than 400°C, a large amount of quinoline insoluble matter will be generated in the resulting pitch during mesophase formation, resulting in coking and coking during the melt spinning process.
Problems such as phase separation and increase in softening point are likely to occur, and the performance of the resulting carbon fibers is also poor, which is undesirable. Also, if the heat treatment temperature is higher than 500℃, problems such as coking will occur during the raw material pitch manufacturing stage.
In fact, it becomes difficult to produce raw material pitches. After the heat treatment, it is also preferable to remove light components by distillation or the like, if necessary. By using the raw material pitch of the present invention thus obtained, when heat-treated to form a mesophase, the production of high molecular weight components that are insoluble in quinoline is suppressed, and at the same time, the softening point of the pitch is prevented from increasing. Furthermore, it becomes a good precursor pitch having a composition in which the aromatic planes are easily arranged in an orderly manner. As a result, carbon fibers with extremely excellent elastic modulus and strength can be obtained. A known method can be used to produce carbon fiber using the raw material pitch obtained according to the present invention. That is, a raw material pitch is heat-treated to form a mesophase, the resulting precursor pitch is melt-spun, and then subjected to infusibility treatment and carbonization or further graphitization treatment to produce carbon fibers. The reaction at the stage of heat-treating the raw material pitch to convert it into a mesophase to obtain the precursor pitch is usually carried out at a temperature
The reaction is carried out at a temperature of 340 to 450°C, preferably 370 to 420°C, by bubbling an inert gas such as nitrogen under normal pressure or reduced pressure. The heat treatment time at this time can be arbitrarily determined depending on conditions such as temperature and amount of inert gas aeration, but it is usually carried out for 1 to 50 hours, preferably 3 to 20 hours. The amount of inert gas ventilation is
A pitch of 0.7 to 5.0 scfh/1b is preferred. As a method for melt-spinning the precursor pitch, known methods such as an extrusion method, a centrifugation method, and an atomization method can be used. The pitch fiber obtained by melt spinning is then subjected to an infusible treatment in an oxidizing gas atmosphere. As the oxidizing gas, one or more of oxidizing gases such as oxygen, ozone, air, nitrogen oxide, halogen, and sulfur dioxide gas are usually used. This infusibility treatment is carried out under temperature conditions that do not soften or deform the melt-spun pitch fibers to be treated. for example
Temperatures of 20-360°C, preferably 20-300°C are employed. Further, the treatment time is usually 5 minutes to 10 hours. The infusible pitch fibers are then carbonized or further graphitized in an inert gas atmosphere to obtain carbon fibers. Carbonization is usually performed at a temperature of 800 to 2500℃, and the processing time generally required for carbonization is 0.5 minutes to
It is 10 hours. Further, when graphitizing is carried out, it is carried out at a temperature of 2500 to 3500°C, usually for 1 second to 1 hour. In addition, during infusibility, carbonization or graphitization treatment,
If necessary, a slight load or tension may be applied to the object to be processed in order to prevent shrinkage, deformation, etc. The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto. Example 1 Heavy oil with a boiling point of 200°C or higher (hereinafter abbreviated as heavy oil (1)) was produced as a by-product when naphtha was steam cracked at 830°C.
The properties are shown in Table 1) and hydrotreated vacuum gas oil (VGO) of Arabian crude oil were catalytically cracked at 500℃ using a silica-alumina catalyst. A mixture of 50 g of heavy oil (hereinafter abbreviated as heavy oil (2), whose properties are shown in Table 2) was heated at an initial hydrogen pressure of 100 Kg/cm 2 G in an autoclave with an internal volume of 300 ml and equipped with a stirrer. Heating rate 3
Heat to 435°C at °C/min and hold at 435°C for 2.5 hours. Thereafter, heating was stopped and the mixture was cooled to room temperature. The obtained liquid product was distilled at 250° C./1 mmHg to remove light components and obtain raw material pitch. The softening point of this pitch was 63°C, the quinoline insoluble content was 0%, and the yield was 35 wt%. Next, add 600 g of nitrogen to 30 g of this raw material pitch.
Stir with ventilation at ml/min, heat treatment at 400℃ for 10 hours, softening point 268℃, quinoline insoluble content.
Pitch with a mesophase content of 27 wt% and 88% was obtained in a yield of 47%. Set this pitch to a nozzle diameter of 0.3mmφ, L/
Melt-spun at 320℃ using a D=2 spinner, and
Pitch fibers with a diameter of 15 μm were produced, and further subjected to infusible, carbonized and graphitized treatments under the conditions shown below to obtain carbon fibers. ΓInfusibility conditions: 3 in air atmosphere up to 200℃
℃/min, heat at a rate of 1℃/min up to 300℃, and hold at 300℃ for 15 minutes. Γ Carbonization conditions: In a nitrogen atmosphere, temperature was increased at 5°C/min.
Hold at 1000℃ for 30 minutes. Γ Graphitization conditions: Heat treatment in an argon stream at a heating rate of 25°C/min to 2500°C. The obtained carbon fiber had a tensile strength of 285 Kg/mm 2 and a Young's modulus of 47 ton/mm 2 . As shown in Comparative Example 1, the carbon fiber obtained using the raw material pitch of the present invention has higher strength and It is clear that the elastic modulus is high.
【表】【table】
【表】【table】
【表】
比較例 1
実施例1において使用した本発明の原料ピツチ
の代わりに、市販の石油ピツチであるアツシユラ
ンド(Ashland)240LS(軟化点120℃)を用い
て、実施例1と同様な方法で熱処理を行つたとこ
ろ、メソ相含量50%のピツチを得た。このピツチ
を実施例1と同様の方法で溶融紡糸、不融化処
理、炭化および黒鉛化処理して炭素繊維を得た。
得られた炭素繊維の引張強度は137Kg/mm2、ヤ
ング率は23ton/mm2であつた。
比較例 2
実施例1で用いた重質油(1)100gと重質油(2)50
gとの混合物を内容積300mlの撹拌機付きオート
クレーブ中で水素初圧100Kg/cm2・Gで昇温速度
3℃/minで340℃まで加熱し、340℃で3時間保
持した。しかる後、加熱を停止し、室温まで冷却
した。
得られた液状生成物を250℃/1mmHgで蒸留し
て軽質分を留出させ原料ピツチを得た。このピツ
チの軟化点は49℃、キノリン不溶分は0%であ
り、収率は52wt%であつた。
次にこの原料ピツチ30gに対し、窒素を600
ml/分で通気しながら撹拌し、温度400℃で8時
間熱処理を行い、軟化点325℃、キノリン不溶分
53wt%、メソ相割合90%のピツチを34%の収率
で得た。このピツチを実施例1と同様の方法で溶
融紡糸しようとしたところ、糸が不均一となり連
続的に紡糸することが不可能であつた。[Table] Comparative Example 1 In place of the raw material pitch of the present invention used in Example 1, Ashland 240LS (softening point 120°C), which is a commercially available petroleum pitcher, was used in the same manner as in Example 1. After heat treatment, a pitch with a mesophase content of 50% was obtained. This pitch was subjected to melt spinning, infusibility treatment, carbonization and graphitization treatment in the same manner as in Example 1 to obtain carbon fibers. The obtained carbon fiber had a tensile strength of 137 Kg/mm 2 and a Young's modulus of 23 ton/mm 2 . Comparative example 2 100 g of heavy oil (1) used in Example 1 and 50 g of heavy oil (2)
In an autoclave with an internal volume of 300 ml and equipped with a stirrer, the mixture was heated to 340°C at a temperature increase rate of 3°C/min at an initial hydrogen pressure of 100 kg/cm 2 ·G, and maintained at 340°C for 3 hours. Thereafter, heating was stopped and the mixture was cooled to room temperature. The obtained liquid product was distilled at 250° C./1 mmHg to remove light components and obtain raw material pitch. The softening point of this pitch was 49°C, the quinoline insoluble content was 0%, and the yield was 52 wt%. Next, add 600 g of nitrogen to 30 g of this raw material pitch.
Stir with ventilation at a rate of ml/min, heat treat at 400℃ for 8 hours, softening point: 325℃, quinoline insoluble content
Pitch with a mesophase content of 53 wt% and 90% was obtained in a yield of 34%. When an attempt was made to melt-spun this pitch in the same manner as in Example 1, the yarn became non-uniform and continuous spinning was impossible.
Claims (1)
ツチを溶融紡糸した後、不融化処理および炭化あ
るいはさらに黒鉛化処理して炭素繊維を製造する
に当たり、該原料ピツチが(1)石油類を水蒸気分解
した際に得られる沸点200℃以上の重質油と(2)石
油類を流動接触分解した際に得られる沸点200℃
以上の重質油との混合物を20Kg/cm2・G以上の水
素加圧下で、温度400〜500℃で熱処理することに
より得られるものであることを特徴とする炭素繊
維用原料ピツチの製造方法。1. After melt-spinning a precursor pitch obtained by heating a raw material pitch, infusibility treatment and carbonization or further graphitization treatment to produce carbon fibers, the raw material pitch is subjected to (1) steam decomposition of petroleum. (2) Heavy oil with a boiling point of 200°C or higher obtained when performing fluid catalytic cracking of petroleum
A method for producing raw material pitch for carbon fiber, characterized in that it is obtained by heat-treating the above mixture with heavy oil at a temperature of 400 to 500°C under hydrogen pressure of 20 kg/cm 2 ·G or more. .
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11633281A JPS5818420A (en) | 1981-07-27 | 1981-07-27 | Raw material pitch for carbon fiber |
US06/366,862 US4391788A (en) | 1981-04-13 | 1982-04-09 | Starting pitches for carbon fibers |
CA000400900A CA1181709A (en) | 1981-04-13 | 1982-04-13 | Starting pitches for carbon fibers |
EP82301911A EP0063051B1 (en) | 1981-04-13 | 1982-04-13 | Starting pitches for carbon fibers |
DE8282301911T DE3265549D1 (en) | 1981-04-13 | 1982-04-13 | Starting pitches for carbon fibers |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11633281A JPS5818420A (en) | 1981-07-27 | 1981-07-27 | Raw material pitch for carbon fiber |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5818420A JPS5818420A (en) | 1983-02-03 |
JPH0144753B2 true JPH0144753B2 (en) | 1989-09-29 |
Family
ID=14684341
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11633281A Granted JPS5818420A (en) | 1981-04-13 | 1981-07-27 | Raw material pitch for carbon fiber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5818420A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6250388A (en) * | 1985-08-28 | 1987-03-05 | Osaka Gas Co Ltd | Production of pitch for making carbon fiber |
-
1981
- 1981-07-27 JP JP11633281A patent/JPS5818420A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS5818420A (en) | 1983-02-03 |
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