JP3695007B2 - Manufacturing method of optical isotropic pitch - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、汎用炭素繊維・活性炭素繊維・アモルファス系二次電池負極材などの種々炭素材原料に用いられる、不融化性に優れた光学的等方性ピッチの製造法に関する。
【０００２】
【従来の技術】
従来、光学的等方性ピッチは、石炭系あるいは石油系ピッチから製造されており、特開平６−２５６７６７号および特公平７−１８０５８号には、コールタールなどの原料を使用し、原料の濾過・減圧蒸留・空気吹き込み等の処理を行うことにより不融化性に優れた光学的等方性ピッチを得る方法が記載されている。
しかしこの光学的等方性ピッチを紡糸して得られたピッチファイバーを不融化するには高温で長時間の保持が必要であり、その改良が求められている。
【０００３】
また特開昭６３−１４６９２０号には、縮合多環芳香族炭化水素またはこれを含有する物質を、ＨＦ・ＢＦ３触媒の存在下で重合させ、炭素繊維及びその他の高性能炭素材料として好適なピッチが製造できることが開示されている。ここで得られた等方性ピッチを炭素繊維等の原料とした場合、その軟化点が低いため紡糸時に融着が発生し易く、繊維の不融化に非常に長い時間を要する。このため軟化点を上げるべく反応条件を操作した場合には、特開平１−１３９６２１号に記載されているように、得られたピッチに光学的異方性組織が発生し、実質的に等方性ピッチでなくなる。
【０００４】
【発明が解決しようとする課題】
上記の如く石炭系あるいは石油系ピッチからの炭素繊維製造の際、不融化に要する時間が長いことは、生産性向上の点から重要な課題である。特に光学的等方性ピッチを原料とし得られたピッチファイバーは、光学的異方性ピッチを原料とし得られるピッチファイバーに比べて、不融化に要する時間が長く、不融化処理が困難である。
汎用炭素繊維・活性炭素繊維・アモルファス系二次電池負極材などの種々炭素材用途に対しては、ピッチファイバーまたは種々大きさに粉砕されたピッチ粒子等の不融化処理が容易に行える光学的等方性ピッチが求められている。
本発明の目的は、汎用炭素繊維・活性炭素繊維・アモルファス系二次電池負極材などの種々炭素材用途に対し、不融化性に優れた光学的等方性ピッチの製造方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者らは、上記の如き課題を有する光学的等方性ピッチの製造方法について鋭意検討した結果、ＨＦ・ＢＦ3 触媒の存在下で縮合多環芳香族炭化水素またはこれらを含有する物質を重合させて得られる光学的等方性ピッチを、加熱下に酸化性ガスを流通させ改質することにより、ピッチファイバーの不融化性が極めて優れたものとなるを見い出し、本発明に到達した。
即ち本発明は、縮合多環芳香族炭化水素またはこれらを含有する物質をＨＦ・ＢＦ3 触媒の存在下で重合させ、得られたピッチを加熱下に酸化性ガスを流通することを特徴とする光学的等方性ピッチの製造法である。
【０００６】
【発明の実施の形態】
本発明において原料に用いられる縮合多環芳香族炭化水素としては、ナフタレン・アントラセン・メチルナフタレン・ジメチルナフタレン等及びそれらを含有する石油留分、石油加工工程の残油および石炭タール留分等を挙げることができる。これらの化合物は単独で使用しても良く、また２種類以上の混合物を使用しても良い。
【０００７】
縮合多環芳香族炭化水素の重合反応にはフッ化水素・三フッ化ホウ素（ＨＦ・ＢＦ3 ）が使用され、その触媒量は縮合多環芳香族炭化水素１モルに対して、フッ化水素０．１〜１０倍モル、３フッ化ホウ素が０．０５〜５倍モルである。反応温度は室温〜２５０℃で、好ましくは４０℃〜２２０℃である。反応温度が低すぎる場合は重合度の低く、好適な光学的等方性ピッチが得られない。反応温度が高すぎる場合は光学的異方性組織が出現し光学的等方性ピッチでなくなる。
重合反応に要する時間は通常５〜３００分であり、好ましくは３０〜２４０分である。反応圧力に特に制限はなく、通常自生圧下で行われる。
【０００８】
重合反応終了後、触媒、未反応物、軽沸分は常法により除去される。例えば反応後系内の落圧で触媒を回収することができ、この際にストリッピングガスを用いたり系内温度をより高温にすることで効率的に触媒が回収される。また触媒回収後、不活性ガスのストリッピング等により未反応原料や軽沸分等を生成物から除去することができる。
【０００９】
重合反応により得られたピッチの軟化点は２００℃以下であり、好ましくは４０〜１８０℃である。軟化点が低い場合そのピッチの分子量は一般的に小さく、その後の高温下での酸化性ガス処理で得られる等方性ピッチの収率を下げることとなるので好ましくない。軟化点が２００℃を超える場合は原料によって異なるが、ピッチの光学的組織中に異方性組織が発生し易く、実質的等方性でなくなり、目的とするピッチが得られない。
【００１０】
上記の重合ピッチは加熱下に酸化性ガスを流通することにより改質される。改質に用いる酸化性ガスには、酸素・空気・窒素酸化物などの酸化性ガスが使用できるが、安全性・制御性から空気の使用が好適に用いられる。
ピッチの改質は、溶融状態のピッチに酸化性ガスを吹き込むことで行われる。改質温度は重合ピッチの軟化点により一概に特定されるものでないが、２００〜４００℃、好ましくは３００〜３６０℃である。改質温度が低い場合、ピッチの酸化反応が遅く改質が困難となる。また温度が高い場合、酸化反応が早くなりその制御が困難となり、またピッチ自体の熱重合も起こりやすくなるため目的とするピッチが得られなくなる。
【００１１】
酸化性ガスの流量は、ガスの種類、ピッチの軟化点、反応温度等により異なるが、制御の容易な空気を酸化性ガスとして使用した場合、ピッチに対して１〜５０ｍｌ／ｇ、好ましくは３〜３０ｍｌ／ｇである。改質方法は特に限定されないが、接触効率を上げるためガス吹き出し口でのメッシュ・フィルターや攪拌機が好適に使用される。酸化性ガスによる改質の終了点は、改質の進行に伴い軟化点が上昇するため、この軟化点の測定により判断できる。
【００１２】
酸化性ガスにより改質された光学的等方性ピッチは、必要に応じて溶融状態で径０．１〜０．３ｍｍ程度のノズルに通過させてピッチファイバーとされる。改質ピッチの軟化点は１８０〜３５０℃であり、好ましくは２００〜３００℃である。軟化点が１８０℃より低い場合には、ピッチファイバーとしてもピッチ粒子でも、不融化処理を低温から開始する必要があり結果として処理に長時間を要し、不融化性ガ低くなる。軟化点が３５０℃を超える場合、多くの装置でそのピッチの移送等の操作が困難となり生産性の点から実用的でなくなる。またピッチを溶融紡糸するには、軟化点は３００℃以下であることが好ましい。
【００１３】
以上、本発明において光学的等方性とは偏光顕微鏡観察において、光学的に等方性を示す部分が実質的に１００％であることを意味する。また軟化点は定荷重押し出し型細管レオメーターにより測定される。ピッチファイバーの不融化状況はライターテストにより容易に判定することができ、ライター火炎中に繊維を入れると、不融化が未完の場合には繊維がだらりと変形もしくは溶融するのに対して、不融化が完了している場合には繊維形態を保持したまま、繊維が炎の中で赤熱する。
【００１４】
本発明の方法により改質された光学的等方性ピッチは、ピッチファイバーとしてもピッチ粒子でも、不融化処理が極めて容易である。例えば室温より空気中で４℃／分で 320℃まで昇温すれば不融化され、昇温後の温度保持は不要であり、従来のピッチと比較して不融化時間が大幅に削減される。
本発明の方法により改質された光学的等方性ピッチは汎用炭素繊維・活性炭素繊維または二次電池の負極材などの炭素材料に好適に用いることができる。
【００１５】
【実施例】
次に実施例により本発明をさらに詳しく説明するが、但し本発明はこれら実施例により制限されない。なお以下の実施例において軟化点の測定および不融化状況の判定は上記に記載の方法により行った。
【００１６】
実施例１
内容積３Ｌの攪拌機を装備した耐酸オートクレーブに、α、β混合メチルナフタレン７モル、フッ化水素５．１５モルを仕込み、ゆっくり攪拌しながら三フッ化ホウ素１．４モルを供給した。次に反応温度１００℃で４時間攪拌下で重合反応を行った。反応後落圧により触媒を回収し、２００℃で１６時間の間窒素を毎分３Ｌ吹き込みながら残留触媒、未反応原料ならびに軽沸分の除去を行った。得られた重合ピッチの軟化点は７６℃であった。
次に該重合ピッチを別の反応器に仕込み、窒素を吹き込みながら攪拌下３４０℃まで昇温を行った。内容物温度が３４０℃に安定したところで吹き込みガスを窒素から空気に切り替えピッチの改質を実施した。このときの空気流量は２０Ｌ／ｋｇとした。１時間の改質反応を行った後、ガスの窒素への切り替え及び冷却により反応を停止した。得られた改質ピッチの軟化点は２４６℃であり、ピッチを偏光顕微鏡観察を行ったところ、光学的組織は１００％等方性であった。
次にこの改質ピッチを径０．１５ｍｍのノズルで溶融紡糸を行いピッチファイバーを得た。このピッチファイバーを空気中室温から３２０℃まで４℃／分の昇温速度で昇温し、３２０℃に到達後、装置外に取り出した。
不融化処理後の繊維に融着は認められず不融化は完全に行われていた。また焼成も実施したが、焼成後の融着もなかった。
またこの改質ピッチをボールミルで粉砕し、粒状のまま同様の方法で不融化を行ったが繊維と同様に不融化性は良好であった。
【００１７】
実施例２
内容積３Ｌの攪拌機を装備した耐酸オートクレーブに、コールタールのメチルナフタレン留分２８４ｇ、フッ化水素１．４６モルを仕込み、ゆっくり攪拌しながら三フッ化ホウ素０．４モルを供給した。次に反応温度１３５℃で４時間攪拌下で反応を行った。反応後落圧により触媒を回収し、２９５℃で１６時間窒素を毎分３Ｌ吹き込みながら残留触媒、未反応原料ならびに軽沸分の除去を行った。得られた重合ピッチの軟化点は８９℃であった。
次に該重合ピッチの改質を実施例１と同様の方法で実施した。改質に要した時間は４０分であった。改質ピッチの軟化点は２２０℃で光学的組織は１００％等方性であった。
次にこの改質ピッチの溶融紡糸を実施例１と同様の方法で行いピッチファイバーを得た。このピッチファイバーを空気中室温から３２０℃まで４℃／分の昇温速度で昇温し、３２０℃に到達後、装置外に取り出した。
不融化処理後の繊維に融着は認められず不融化は完全に行われていた。この不融化繊維を１５％の二酸化炭素含む窒素ガスを用いて１０００℃で一時間賦活処理を行い活性炭素繊維を得た。得られた活性炭素繊維のヨウ素吸着量は１９４０ｍｇ／ｇであった。
【００１８】
比較例１
市販のコールタールピッチを反応器に仕込み、窒素を吹き込みながら攪拌下３２０℃まで昇温を行った。内容物温度が３２０℃に安定したところで吹き込みガスを窒素から空気に切り替えピッチの改質を実施した。このときの空気流量は２０Ｌ／ｋｇであった。１時間の反応を行った後、ガスの窒素への切り替え及び冷却により反応を停止した。得られた改質ピッチの軟化点は２２７℃で、光学的組織は１００％等方性であった。
次にこの改質ピッチの溶融紡糸を行いピッチファイバーを得た。このピッチファイバーを空気中室温から３２０℃まで４℃／分の昇温速度で昇温し、３２０℃に到達後、装置外に取り出した。
不融化処理後の繊維は完全に融着しており不融化は不完全であった。
【００１９】
比較例２
内容積３Ｌの攪拌機を装備した耐酸オートクレーブに、ナフタレン１０モル、フッ化水素２．０７モルを仕込み、ゆっくり攪拌しながら三フッ化ホウ素１．１５モルを供給した。次に反応温度２１０℃で４時間攪拌下で反応を行った。反応後落圧により触媒を回収し、６４０℃で１６時間窒素を毎分３Ｌ吹き込みながら残留触媒、未反応原料ならびに軽沸分の除去を行った。得られた重合ピッチの軟化点は１７３．６℃で、光学的組織は１００％等方性であった。
次に該重合ピッチを改質せずに、溶融紡糸を実施例１と同様の方法で行いピッチファイバーを得た。このピッチファイバーを空気中室温から３２０℃まで４℃／分の昇温速度で不融化処理を実施したが、繊維に溶融した跡があり、不融化が出来ていなかった。
【００２０】
【発明の効果】
以上の実施例からも明らかなように、本発明の方法により得られた光学的等方性ピッチは、例えば室温より空気中で４℃／分で 320℃まで昇温すれば不融化され、昇温後の温度保持は不要であることから、従来のピッチと比較して不融化性に極めて優れており、不融化時間が大幅に削減される。本発明のピッチは従来の汎用炭素繊維・活性炭素繊維・アモルファス系二次電池負極材等の原料として使用され、短時間で容易に不融化できることから、その生産性を向上できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an optically isotropic pitch excellent in infusibilities used for various carbon material raw materials such as general-purpose carbon fibers, activated carbon fibers, and amorphous secondary battery negative electrode materials.
[0002]
[Prior art]
Conventionally, optically isotropic pitches have been manufactured from coal-based or petroleum-based pitches. In JP-A-6-256767 and JP-B-7-18058, a raw material such as coal tar is used, and the raw material is filtered. Describes a method for obtaining an optically isotropic pitch having excellent infusibilities by performing treatments such as vacuum distillation and air blowing.
However, in order to infusibilize a pitch fiber obtained by spinning this optically isotropic pitch, it is necessary to keep it at a high temperature for a long time, and an improvement is required.
[0003]
JP-A-63-146920 discloses a pitch suitable for carbon fiber and other high-performance carbon materials by polymerizing a condensed polycyclic aromatic hydrocarbon or a substance containing the same in the presence of an HF / BF3 catalyst. Is disclosed that can be manufactured. When the isotropic pitch obtained here is used as a raw material for carbon fiber or the like, its softening point is low, so that fusion is likely to occur during spinning, and a very long time is required for infusibility of the fiber. For this reason, when the reaction conditions are manipulated to increase the softening point, as described in JP-A-1-139621, an optically anisotropic structure is generated in the obtained pitch, which is substantially isotropic. It is not sex pitch.
[0004]
[Problems to be solved by the invention]
As described above, when producing carbon fiber from coal-based or petroleum-based pitch, a long time required for infusibilization is an important issue from the viewpoint of improving productivity. In particular, a pitch fiber obtained using an optically isotropic pitch as a raw material has a longer time required for infusibility than a pitch fiber obtained using an optically anisotropic pitch as a raw material, and is infusible.
For various carbon materials such as general-purpose carbon fibers, activated carbon fibers, and amorphous secondary battery negative electrode materials, optical fibers that can easily infusibilize pitch fibers or pitch particles pulverized to various sizes, etc. An isotropic pitch is required.
An object of the present invention is to provide a method for producing an optically isotropic pitch having excellent infusibilities for various carbon materials such as general-purpose carbon fibers, activated carbon fibers, and amorphous secondary battery negative electrode materials. is there.
[0005]
[Means for Solving the Problems]
As a result of intensive studies on a method for producing an optically isotropic pitch having the above-mentioned problems, the present inventors have found that condensed polycyclic aromatic hydrocarbons or substances containing these in the presence of an HF · BF 3 catalyst. The optically isotropic pitch obtained by polymerization was found to be excellent in infusibilities of the pitch fiber by modifying an optically isotropic pitch by passing an oxidizing gas under heating, and reached the present invention.
That is, the present invention is characterized in that a condensed polycyclic aromatic hydrocarbon or a substance containing these is polymerized in the presence of an HF · BF 3 catalyst, and an oxidizing gas is passed through the obtained pitch while heating. This is a method for producing an optically isotropic pitch.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the condensed polycyclic aromatic hydrocarbon used as a raw material in the present invention include naphthalene, anthracene, methylnaphthalene, dimethylnaphthalene and the like, and petroleum fractions containing them, residual oil in a petroleum processing step, and coal tar fractions. be able to. These compounds may be used alone or in combination of two or more.
[0007]
Hydrogen fluoride / boron trifluoride (HF / BF 3 ) is used for the polymerization reaction of condensed polycyclic aromatic hydrocarbons, and the catalyst amount is hydrogen fluoride per mole of condensed polycyclic aromatic hydrocarbons. 0.1 to 10 times mol of boron trifluoride is 0.05 to 5 times mol. The reaction temperature is room temperature to 250 ° C, preferably 40 ° C to 220 ° C. When the reaction temperature is too low, the degree of polymerization is low, and a suitable optical isotropic pitch cannot be obtained. When the reaction temperature is too high, an optically anisotropic structure appears and the optical isotropic pitch is lost.
The time required for the polymerization reaction is usually 5 to 300 minutes, preferably 30 to 240 minutes. There is no restriction | limiting in particular in reaction pressure, Usually, it carries out under autogenous pressure.
[0008]
After completion of the polymerization reaction, the catalyst, unreacted substances, and light boiling components are removed by a conventional method. For example, the catalyst can be recovered by the pressure drop in the system after the reaction. At this time, the catalyst is efficiently recovered by using a stripping gas or by increasing the temperature in the system. In addition, after the catalyst is recovered, unreacted raw materials, light boiling components, and the like can be removed from the product by stripping inert gas or the like.
[0009]
The softening point of the pitch obtained by the polymerization reaction is 200 ° C. or less, preferably 40 to 180 ° C. When the softening point is low, the molecular weight of the pitch is generally small, and the yield of the isotropic pitch obtained by oxidizing gas treatment at a high temperature thereafter is lowered, which is not preferable. When the softening point exceeds 200 ° C., it varies depending on the raw material. However, an anisotropic structure is easily generated in the optical structure of the pitch, and is not substantially isotropic, so that the desired pitch cannot be obtained.
[0010]
The polymerization pitch is modified by passing an oxidizing gas under heating. As the oxidizing gas used for the reforming, an oxidizing gas such as oxygen, air, or nitrogen oxide can be used, but the use of air is preferably used from the viewpoint of safety and controllability.
The modification of the pitch is performed by blowing an oxidizing gas into the molten pitch. The reforming temperature is not generally specified by the softening point of the polymerization pitch, but is 200 to 400 ° C, preferably 300 to 360 ° C. When the reforming temperature is low, the pitch oxidation reaction is slow and the reforming becomes difficult. Further, when the temperature is high, the oxidation reaction is accelerated and the control thereof becomes difficult, and thermal polymerization of the pitch itself easily occurs, so that the target pitch cannot be obtained.
[0011]
The flow rate of the oxidizing gas varies depending on the type of gas, the softening point of the pitch, the reaction temperature, etc., but when easily controlled air is used as the oxidizing gas, it is 1 to 50 ml / g, preferably 3 ~ 30 ml / g. The reforming method is not particularly limited, but a mesh filter or a stirrer at the gas outlet is preferably used in order to increase the contact efficiency. The end point of the reforming with the oxidizing gas can be judged by measuring the softening point because the softening point increases as the reforming proceeds.
[0012]
The optically isotropic pitch modified by the oxidizing gas is passed through a nozzle having a diameter of about 0.1 to 0.3 mm in a molten state as necessary to form a pitch fiber. The softening point of the modified pitch is 180 to 350 ° C, preferably 200 to 300 ° C. When the softening point is lower than 180 ° C., it is necessary to start the infusibilization treatment at a low temperature for both pitch fibers and pitch particles. As a result, the treatment takes a long time and the infusibilities are lowered. When the softening point exceeds 350 ° C., operations such as transfer of the pitch are difficult in many apparatuses, which is not practical from the viewpoint of productivity. For melt spinning the pitch, the softening point is preferably 300 ° C. or lower.
[0013]
As described above, in the present invention, the optical isotropy means that a portion showing optical isotropy is substantially 100% in observation with a polarizing microscope. The softening point is measured by a constant load extrusion type capillary rheometer. The infusibility of the pitch fiber can be easily determined by a lighter test. When the fiber is placed in the lighter flame, the fiber is loosely deformed or melted when infusible is not completed. When is completed, the fiber becomes red hot in the flame while maintaining the fiber form.
[0014]
The optically isotropic pitch modified by the method of the present invention is extremely easy to be infusible as a pitch fiber or pitch particle. For example, if the temperature is raised from room temperature to 320 ° C. at 4 ° C./min in the air, the temperature is infusible, and it is not necessary to maintain the temperature after the temperature rise.
The optically isotropic pitch modified by the method of the present invention can be suitably used for carbon materials such as general-purpose carbon fibers / activated carbon fibers or negative electrode materials for secondary batteries.
[0015]
【Example】
EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following examples, the measurement of the softening point and the determination of the infusibilization state were performed by the methods described above.
[0016]
Example 1
An acid-resistant autoclave equipped with a stirrer with an internal volume of 3 L was charged with 7 mol of α and β mixed methylnaphthalene and 5.15 mol of hydrogen fluoride, and 1.4 mol of boron trifluoride was supplied with slow stirring. Next, the polymerization reaction was carried out with stirring at a reaction temperature of 100 ° C. for 4 hours. After the reaction, the catalyst was recovered by dropping pressure, and the residual catalyst, unreacted raw materials and light boiling components were removed while blowing nitrogen at 3 L / min for 16 hours at 200 ° C. The resulting polymerization pitch had a softening point of 76 ° C.
Next, the polymerization pitch was charged into another reactor, and the temperature was raised to 340 ° C. with stirring while blowing nitrogen. When the temperature of the contents was stabilized at 340 ° C., the blowing gas was changed from nitrogen to air to modify the pitch. The air flow rate at this time was 20 L / kg. After the reforming reaction for 1 hour, the reaction was stopped by switching the gas to nitrogen and cooling. The resulting modified pitch had a softening point of 246 ° C. When the pitch was observed with a polarizing microscope, the optical structure was 100% isotropic.
Next, this modified pitch was melt-spun with a nozzle having a diameter of 0.15 mm to obtain a pitch fiber. The pitch fiber was heated from room temperature in air to 320 ° C. at a rate of 4 ° C./min. After reaching 320 ° C., the pitch fiber was taken out of the apparatus.
No fusion was observed on the fiber after the infusibilization treatment, and the infusibilization was completely performed. Although firing was also performed, there was no fusion after firing.
The modified pitch was pulverized with a ball mill and infusibilized in the same manner as in the granular form. However, the infusibilities were as good as the fibers.
[0017]
Example 2
In an acid-resistant autoclave equipped with a stirrer with an internal volume of 3 L, 284 g of a methylnaphthalene fraction of coal tar and 1.46 mol of hydrogen fluoride were charged, and 0.4 mol of boron trifluoride was supplied while stirring slowly. Next, the reaction was conducted at a reaction temperature of 135 ° C. with stirring for 4 hours. After the reaction, the catalyst was recovered by dropping pressure, and residual catalyst, unreacted raw materials and light boiling components were removed while blowing nitrogen at 295 ° C. for 16 hours per minute. The resulting polymerization pitch had a softening point of 89 ° C.
Next, the modification of the polymerization pitch was carried out in the same manner as in Example 1. The time required for the modification was 40 minutes. The softening point of the modified pitch was 220 ° C. and the optical structure was 100% isotropic.
Next, melt spinning of this modified pitch was performed in the same manner as in Example 1 to obtain a pitch fiber. The pitch fiber was heated from room temperature in air to 320 ° C. at a rate of 4 ° C./min. After reaching 320 ° C., the pitch fiber was taken out of the apparatus.
No fusion was observed on the fiber after the infusibilization treatment, and the infusibilization was completely performed. This infusible fiber was activated at 1000 ° C. for 1 hour using nitrogen gas containing 15% carbon dioxide to obtain activated carbon fiber. The iodine adsorption amount of the obtained activated carbon fiber was 1940 mg / g.
[0018]
Comparative Example 1
A commercially available coal tar pitch was charged into the reactor, and the temperature was raised to 320 ° C. with stirring while blowing nitrogen. When the temperature of the contents was stabilized at 320 ° C., the blowing gas was changed from nitrogen to air to modify the pitch. The air flow rate at this time was 20 L / kg. After performing the reaction for 1 hour, the reaction was stopped by switching the gas to nitrogen and cooling. The resulting modified pitch had a softening point of 227 ° C. and an optical texture of 100% isotropic.
Next, melt spinning of this modified pitch was performed to obtain a pitch fiber. The pitch fiber was heated from room temperature in air to 320 ° C. at a rate of 4 ° C./min. After reaching 320 ° C., the pitch fiber was taken out of the apparatus.
The fiber after the infusibilization treatment was completely fused, and the infusibilization was incomplete.
[0019]
Comparative Example 2
An acid-resistant autoclave equipped with a stirrer with an internal volume of 3 L was charged with 10 moles of naphthalene and 2.07 moles of hydrogen fluoride, and 1.15 moles of boron trifluoride were supplied while slowly stirring. Next, the reaction was carried out at a reaction temperature of 210 ° C. with stirring for 4 hours. After the reaction, the catalyst was recovered by dropping pressure, and the residual catalyst, unreacted raw materials and light boiling components were removed while blowing 3 L / min of nitrogen at 640 ° C. for 16 hours. The resulting polymerization pitch had a softening point of 173.6 ° C. and an optical texture of 100% isotropic.
Next, melt spinning was performed in the same manner as in Example 1 without modifying the polymerization pitch to obtain a pitch fiber. This pitch fiber was infusibilized from room temperature in air to 320 ° C. at a heating rate of 4 ° C./min. However, there was a trace of melting of the fiber, and infusibilization was not achieved.
[0020]
【The invention's effect】
As is clear from the above examples, the optically isotropic pitch obtained by the method of the present invention becomes infusible and rises when the temperature is raised from room temperature to 320 ° C. at 4 ° C./min in air. Since it is not necessary to maintain the temperature after warming, the infusibilization property is extremely excellent compared with the conventional pitch, and the infusibilization time is greatly reduced. The pitch of the present invention can be used as a raw material for conventional general-purpose carbon fibers, activated carbon fibers, amorphous secondary battery negative electrode materials, etc., and can be easily infusible in a short time, so that its productivity can be improved.
Claims (3)
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23667796A JP3695007B2 (en) | 1996-09-06 | 1996-09-06 | Manufacturing method of optical isotropic pitch |
| US08/924,864 US5944980A (en) | 1996-09-06 | 1997-09-05 | Method for producing isotropic pitch, activated carbon fibers and carbon materials for non-aqueous secondary battery anodes |
| EP97306937A EP0838515B1 (en) | 1996-09-06 | 1997-09-08 | A method for producing isotropic pitch, active carbon fibers and carbon materials for non-aqueous secondary battery anodes |
| DE69732825T DE69732825T8 (en) | 1996-09-06 | 1997-09-08 | Process for the preparation of isotropic pitch, active carbon fibers and carbon material for anodes of non-aqueous secondary batteries |
| US09/293,249 US6228343B1 (en) | 1996-09-06 | 1999-04-16 | Method for producing isotropic pitch, activated carbon fibers and carbon materials for non-aqueous secondary battery anodes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23667796A JP3695007B2 (en) | 1996-09-06 | 1996-09-06 | Manufacturing method of optical isotropic pitch |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1081735A JPH1081735A (en) | 1998-03-31 |
| JP3695007B2 true JP3695007B2 (en) | 2005-09-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23667796A Expired - Fee Related JP3695007B2 (en) | 1996-09-06 | 1996-09-06 | Manufacturing method of optical isotropic pitch |
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| Country | Link |
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| JP (1) | JP3695007B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150058007A (en) | 2013-11-19 | 2015-05-28 | 에스케이이노베이션 주식회사 | Method of feed stock for isotropic pitch |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110272754B (en) * | 2019-05-13 | 2020-11-17 | 湖南东映碳材料科技有限公司 | Preparation method of high-purity aromatic hydrocarbon asphalt for high-end carbon material |
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- 1996-09-06 JP JP23667796A patent/JP3695007B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150058007A (en) | 2013-11-19 | 2015-05-28 | 에스케이이노베이션 주식회사 | Method of feed stock for isotropic pitch |
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| Publication number | Publication date |
|---|---|
| JPH1081735A (en) | 1998-03-31 |
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