JPH0637724B2 - Carbon fiber manufacturing method - Google Patents

Description

【発明の詳細な説明】 本発明はアクリル系前駆体繊維から炭素繊維を製造する
に際し、前駆体繊維および炭素繊維を製造工程並びに製
品における単繊維間の融着を防止し、より生産性良く高
品質の炭素繊維を得るための改善された炭素繊維の製造
方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION In the present invention, when a carbon fiber is produced from an acrylic precursor fiber, the process of producing the precursor fiber and the carbon fiber and the fusion between the single fibers in the product are prevented, resulting in higher productivity and higher productivity. It relates to an improved method for producing carbon fibers to obtain quality carbon fibers.

従来、アクリル系繊維は炭素繊維、特に高強力，高弾性
率のいわゆる“ハイグレード”炭素繊維の製造用原料と
して広く使用されている。Conventionally, acrylic fibers have been widely used as a raw material for producing carbon fibers, especially so-called "high grade" carbon fibers having high strength and high elastic modulus.

一般にアクリル系繊維の紡糸方法としては、紡糸原液を
湿式，乾−湿式，乾式などで紡糸する方法があるが、こ
れらの方法にはそれぞれ凝固・水洗・熱延伸・油剤付与
・乾燥緻密化工程からなつているために、熱延伸工程，
ニップローラーによる脱水工程，乾燥緻密化工程などで
複数本の単繊維同志が融着（以下、単に融着という）し
やすいという問題がある。Generally, as a method for spinning an acrylic fiber, there is a method in which a spinning dope is spun by a wet method, a dry-wet method, a dry method, or the like. Each of these methods includes coagulation, washing with water, hot drawing, application of an oil agent, and dry densification step. Because of this, the hot drawing process,
There is a problem that a plurality of single fibers are likely to be fused (hereinafter simply referred to as fusion) in a dehydration process using a nip roller and a dry densification process.

さらに、アクリル系前駆体繊維（以下、単に前駆体繊維
という）から炭素繊維を製造する工程のうち、酸化性雰
囲気中で加熱処理し繊維構造中にナフチリジン環等の環
化構造を形成せしめる，いわゆる耐炎化工程は極めて重
要な工程である。Furthermore, in the process of producing carbon fibers from acrylic precursor fibers (hereinafter simply referred to as precursor fibers), heat treatment is performed in an oxidizing atmosphere to form a cyclized structure such as a naphthyridine ring in the fiber structure. The flameproofing process is a very important process.

この耐炎化工程では前駆体繊維が少なくとも２００℃以
上という苛酷な条件下に加熱されるため、該前駆体繊維
は急激に化学的に変性し、かつ多量の熱分解物が発生
し、耐炎化工程を汚染するために必然的に融着を起しや
すい。In this flame-proofing step, the precursor fiber is heated under severe conditions of at least 200 ° C. or more, so that the precursor fiber is rapidly chemically modified and a large amount of thermal decomposition product is generated. It is inevitable that fusion will occur due to contamination.

このような融着を防止し、得られる炭素繊維の品質を保
持するために耐炎化工程の加熱温度を下げると、長時間
の加熱処理を余儀なくされ、工業的生産性が低下し、製
品コストが高くなるという欠点がある。When such a fusion is prevented and the heating temperature in the flameproofing step is lowered in order to maintain the quality of the obtained carbon fiber, a long heat treatment is unavoidable, the industrial productivity is lowered, and the product cost is reduced. It has the drawback of being expensive.

さらに、前述の如き前駆体繊維の紡糸工程で発生する融
着，および耐炎化工程で発生する融着が多くなると、紡
糸工程，耐炎化工程，炭化工程での糸切れが頻発し、ロ
ーラーへの巻付き，毛羽の発生が多くなり、さらには得
られた炭素繊維の品質の低下が著しくなるということは
一般によく知られているところである。Furthermore, when the fusion generated in the spinning process of the precursor fiber as described above and the fusion generated in the flameproofing process increase, yarn breakage frequently occurs in the spinning process, the flameproofing process, and the carbonization process, and It is generally well known that the occurrence of wrapping and fluffing increases and that the quality of the obtained carbon fiber significantly decreases.

したがって、かかる融着を防止することは高品質の炭素
繊維を得るためのみならず、工業的生産性を向上させ製
品コストを低減させるために必要かつ重要な要件であ
る。Therefore, preventing such fusion is a necessary and important requirement not only for obtaining high-quality carbon fiber but also for improving industrial productivity and reducing product cost.

以上述べた融着の問題に加えて、該融着現象は繊維表面
の粗滑の程度によつて差が認められ、表面が滑らかで凸
凹が少ない繊維ほど融着が発生しやすい。換言すれば単
繊維間の接触面積が大きいほど融着が発生しやすいと推
測されるが、このような意味において、微粒子を使用し
て単繊維間の融着を防止する方法としては、特開昭４９
−１０２９３０号公報に開示されている発明がある。In addition to the above-mentioned problem of fusion, the fusion phenomenon is different depending on the degree of coarse sliding of the fiber surface, and the more smooth the surface and the less uneven the fibers, the more likely fusion will occur. In other words, it is presumed that the larger the contact area between the single fibers, the easier the fusion will occur. In this sense, as a method for preventing fusion between the single fibers by using fine particles, Japanese Patent Application Laid-Open No. Sho 49
There is an invention disclosed in Japanese Patent Publication No. 102930.

この発明は静電気で開繊された前駆体繊維に、界面活性
剤で分散させた平均粒子径が２０μ以下で８μ以下の粒
子径のものの全体に占める割合いが４０重量％以上の炭
素粒子を付着させる方法であるから、明らかに紡糸時に
発生する融着に対しては何らの効果も無いし、また直径
十数μの単繊維が数千〜数万本集束されてなる繊維束に
対しては、繊維束を構成する単繊維間に均一に前述のよ
うな粒子を付着させることは極めて困難である。かつ繊
維の構成本数が増すにつれて静電気による開繊も難しく
なるから、粒子の付着ムラが増加するのを避けられない
し、耐炎化工程における融着防止効果も小さく、工業的
には採用し難いと言える。さらに、炭化後の炭素繊維表
面に炭素粒子が付着残存するのを防止できないためにそ
の後に必要に応じて施される表面電解処理工程，サイジ
ング付与工程の汚染が問題になる。According to the present invention, carbon particles having an average particle size of 20 μm or less and a particle size of 8 μm or less dispersed in a surfactant are attached to a precursor fiber opened by static electricity in an amount of 40% by weight or more. Since it is a method of making it, obviously there is no effect on fusion that occurs at the time of spinning, and for a fiber bundle formed by tens to tens of thousands of monofilaments having a diameter of ten and several μ. It is extremely difficult to evenly attach the above-mentioned particles between the single fibers constituting the fiber bundle. And since it becomes difficult to open due to static electricity as the number of constituent fibers increases, it is unavoidable that the uneven adhesion of particles increases, and the effect of preventing fusion in the flameproofing process is small, and it can be said that it is industrially difficult to adopt. . Further, since carbon particles cannot be prevented from adhering and remaining on the surface of the carbon fiber after carbonization, contamination of the surface electrolytic treatment step and the sizing imparting step, which are subsequently performed if necessary, becomes a problem.

そして、この問題を避けるために耐炎化後または炭化後
に超音波洗浄浴などで該炭素粒子を脱落させる工程を設
けると、繊維の配列を乱し、さらには毛羽が発生し、炭
素繊維の品質が低下するので採用できない。Then, in order to avoid this problem, if a step of removing the carbon particles with an ultrasonic cleaning bath or the like is provided after flame resistance or carbonization, the arrangement of the fibers is disturbed, and fluff is further generated, and the quality of the carbon fibers is improved. It cannot be adopted because it decreases.

他方、前駆体繊維に微粒子を付着させる製造法として特
公昭５２−３９４５５号公報に記載の発明がある。これ
は乾燥緻密化される以前のまだ水膨潤状態の繊維を処理
油剤を吸着させた平均粒子径５〜０．０１μの固体微粒
子の分散液中に含浸させることによつて、繊維の細孔中
への油剤の侵入を防げるというものである。しかしなが
ら、この方法も融着防止の点では前述の方法とほぼ同様
な問題がある。すなわち、粒子の付着ムラがあり、粒子
付着工程以降の工程における粒子の脱落による汚染が問
題となるのである。On the other hand, there is an invention described in Japanese Patent Publication No. 52-39455 as a manufacturing method for adhering fine particles to precursor fibers. This is because the fibers in a water-swelled state before being dried and densified are impregnated in a dispersion liquid of solid fine particles having an average particle diameter of 5 to 0.01 μ, which is adsorbed with a treatment oil agent, and It is possible to prevent the invasion of the oil agent into the. However, this method also has a problem similar to the above-mentioned method in terms of preventing fusion. That is, there is uneven adhesion of particles, and contamination due to the particles falling off in the steps after the particle adhesion step becomes a problem.

本発明の目的は上記の如き従来技術の欠点を解消し、高
品質の炭素繊維を生産性良く，かつコストを大きくする
ことなく製造する方法を提供せんとするものである。An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a method for producing high-quality carbon fiber with high productivity and without increasing the cost.

本発明者らはこの目的を達成するために鋭意検討をした
結果、本発明を見い出したものである。The present inventors have found the present invention as a result of extensive studies to achieve this object.

すなわち本発明は平均粒子径０．０１〜０．３５μの黒
鉛微粒子を含有したアクリル系ポリマーの紡糸原液を用
いて紡糸を行なうことによって、該微粒子を１００〜１
０００ｐｐｍの範囲内で繊維を構成するポリマー中に含
有する炭素繊維製造用アクリル系前駆体繊維を得、これ
を焼成することを特徴とする炭素繊維の製造方法であ
る。That is, according to the present invention, 100 to 1 parts of fine particles are obtained by spinning using an acrylic polymer spinning dope containing graphite fine particles having an average particle size of 0.01 to 0.35 μ.
A method for producing a carbon fiber characterized in that an acrylic precursor fiber for producing a carbon fiber contained in a polymer constituting the fiber within a range of 000 ppm is obtained, and the obtained acrylic precursor fiber is fired.

以下、本発明をさらに詳細に説明する。Hereinafter, the present invention will be described in more detail.

本発明において、前駆体繊維に含有される微粒子として
は、焼成中に蒸発したり溶融したりして、炭素繊維の強
度を低下させるものは好ましくなく，さらには、最終製
品としての炭素繊維の耐酸化性を低下させないもの，す
なわち黒鉛微粒子を用いるものである。一般に衣料用合
成繊維においてはツヤ消し剤として酸化チタンを含有さ
せることは公知であり、繊維として伸度が十分あるため
物性的には何ら低下は見られないが、炭素繊維製造用前
駆体繊維は衣料用よりも一般に繊細度の繊維が要求さ
れ、また焼成後の炭素繊維の伸度は極めて低くなるた
め、微粒子の含有に起因して繊維欠陥や異物の形成が生
じ易く、得られる炭素繊維強度はむしろ低下する。In the present invention, as the fine particles contained in the precursor fiber, those which evaporate or melt during firing to reduce the strength of the carbon fiber are not preferable, and further, the acid resistance of the carbon fiber as the final product is not preferable. It does not reduce the chemical conversion property, that is, it uses fine graphite particles. It is generally known that titanium oxide is contained as a matting agent in synthetic fibers for clothing, and there is no reduction in physical properties due to sufficient elongation as fibers, but precursor fibers for carbon fiber production are Generally, finer fibers are required than for clothing, and the elongation of carbon fibers after firing is extremely low, so that the formation of fiber defects and foreign substances is likely to occur due to the inclusion of fine particles, and the resulting carbon fiber strength Rather decreases.

かかる観点から、本発明においては微粒子の平均粒子径
及び含有量が重要であり，平均粒子径が０．３５μを越
えると紡糸時に単糸切れ，毛羽，巻付きの発生が多くな
り、また炭素繊維の大きな欠陥異物となり、炭素繊維の
強度をむしろ低下させる。逆に平均粒子径が０．０１μ
未満では実質的に融着防止効果は認められず、採用され
る平均粒子径としては０．０１〜０．３５μの範囲とす
るものである。From this point of view, in the present invention, the average particle size and content of the fine particles are important. If the average particle size exceeds 0.35μ, single yarn breakage, fluffing, and winding occur frequently during spinning, and the carbon fiber As a large defect foreign matter, which rather reduces the strength of the carbon fiber. Conversely, the average particle size is 0.01μ
If it is less than the above range, the effect of preventing fusion is not substantially recognized, and the average particle size adopted is in the range of 0.01 to 0.35 μ.

他方、微粒子の含有量は実際に使用する微粒子の平均微
粒子径により相違し、融着防止効果並びに紡糸，焼成工
程の操業安定性，炭素繊維の強度等を考慮して決定され
る。すなわち、前記平均粒子径の範囲においては、該微
粒子の含有量は１００〜１０００ｐｐｍとするものであ
る。On the other hand, the content of the fine particles varies depending on the average fine particle diameter of the actually used fine particles, and is determined in consideration of the fusion prevention effect, the operational stability of the spinning and firing steps, the strength of the carbon fibers, and the like. That is, in the range of the average particle diameter, the content of the fine particles is 100 to 1000 ppm.

本発明に用いられるアクリロニトリル系ポリマーとして
は、少なくとも９２モル％のアクリロニトリルと、該ア
クリロニトリルに対して共重合性で耐炎化促進能を有す
るビニル化合物、例えばイタコン酸，アクリル酸，メタ
クリル酸およびそれらのメチルもしくはエチルエステル
類、メタクリロニトリル、アクロレイン等の８モル％以
下との共重合ポリマーを例示することができる。また、
これらのポリマーの重合方法は公知の乳化，懸濁，コロ
イダル，塊状，および溶液の各重合法のいずれも適用で
きるが好ましくは溶液重合がよい。Examples of the acrylonitrile-based polymer used in the present invention include at least 92 mol% of acrylonitrile and vinyl compounds copolymerizable with the acrylonitrile and capable of promoting flame resistance, such as itaconic acid, acrylic acid, methacrylic acid and methyl thereof. Alternatively, a copolymerization polymer with 8 mol% or less of ethyl esters, methacrylonitrile, acrolein, etc. can be exemplified. Also,
As the polymerization method of these polymers, any of known emulsion, suspension, colloidal, bulk, and solution polymerization methods can be applied, but solution polymerization is preferable.

また、使用する薬品類（溶媒，モノマー，重合開始剤，
その他重合助剤等）は純度の高いものを選び、好ましく
はマイクロワインドフイルター，硅土焼結フイルター，
ガラス繊維フイルター，フロロポアフイルター等の組合
せでロ過した後に使用するのがよい。なお、混入する微
粒子は分別をくり返して目的に応じた粒子径にできるだ
けそろえるのがよい。In addition, the chemicals used (solvent, monomer, polymerization initiator,
Other polymerization aids, etc.) should be selected to have a high degree of purity, and preferably microwind filters, silica sintered filters,
It is recommended to use after filtering with a combination of glass fiber filter, fluoropore filter, etc. The fine particles to be mixed should be sorted as much as possible so that the fine particles have a particle diameter suitable for the purpose.

微粒子の混入は、紡糸原液が口金孔から吐出される直前
よりも溶液重合の場合はポリマーを溶媒に溶解する時に
行なう方がより均一に混入できるので好ましい。In the case of solution polymerization, the mixing of fine particles is preferably carried out when the polymer is dissolved in the solvent, since it can be mixed more uniformly than immediately before the spinning solution is discharged from the spinneret hole.

微粒子を混入した紡糸原液は口金前でスタチックミキサ
ー等を用いてさらに均一に微粒子を分解させ、加えて口
金直前でフイルターを用いて他から混入した粗大異物お
よび該微粒子の凝集物をロ過することが好ましい。次い
で口金孔を通し、公知の湿式，乾−湿式，乾式法で紡糸
を行ないアクリル系前駆体繊維を得ることができるが、
この場合に繊維表面が平滑な繊維が得られやすい乾式，
−湿式紡糸法を採用すると融着防止効果が大きくより効
果的で好ましい。The spinning dope containing the fine particles is further decomposed in a uniform manner by using a static mixer or the like before the spinneret, and in addition, coarse foreign matters and aggregates of the fine particles mixed in from other are filtered by using a filter immediately before the spinneret. It is preferable. Then, the acrylic precursor fiber can be obtained by passing through a spinneret hole and spinning by a known wet, dry-wet, or dry method.
In this case, it is easy to obtain fibers with a smooth fiber surface,
The use of the wet spinning method is preferable because it has a large effect of preventing fusion and is more effective.

融着防止効果は、繊維表面，表層部に存在する微粒子に
よつてなされるものであるから、繊維構造を芯鞘構造と
し、鞘部のポリマーに微粒子を混入させ，さらには芯／
鞘の体積比をできるだけ大きくするので好ましい。Since the fusion preventing effect is achieved by the fine particles present on the fiber surface and the surface layer portion, the fiber structure is made into a core-sheath structure, and the fine particles are mixed into the polymer of the sheath portion, and
It is preferable because the volume ratio of the sheath is maximized.

紡糸工程条件は特に限定されるものではなく、公知のア
クリル系繊維の紡糸条件が採用される。The spinning process conditions are not particularly limited, and known acrylic fiber spinning conditions are adopted.

かくして得られた前駆体繊維から炭素繊維を製造するに
際しては、従来公知の焼成方法を採用できるが、一般に
酸化性雰囲気中にて２００〜４００℃で加熱し環化せし
める耐炎化工程と、次いで非酸化性雰囲気中にて１００
０℃以上の温度で処理する炭化，黒鉛化工程からなる焼
成法が採用される。なお、耐炎化の雰囲気としては通常
は空気が用いられる。炭化，黒鉛化の雰囲気としてはチ
ツ素，ヘリウム，アルゴンなどが挙げられ、通常はチツ
素が用いられる。In producing carbon fiber from the precursor fiber thus obtained, a conventionally known firing method can be adopted, but generally, a flameproofing step of heating at 200 to 400 ° C. in an oxidizing atmosphere for cyclization, and then a non-fired step. 100 in oxidizing atmosphere
A calcination method comprising carbonization and graphitization steps of treatment at a temperature of 0 ° C. or higher is adopted. Air is usually used as the flameproof atmosphere. Examples of the atmosphere for carbonization and graphitization include titanium, helium, and argon, and usually titanium is used.

本発明の炭素繊維の製造方法は、その紡糸前にポリマー
中に特定種類，平均粒子径及び含有量の微粒子を混入せ
しめたポリマ溶液から形成された前駆体繊維を焼成する
点に特徴があり、次の如き優れた作用効果を有する。The method for producing the carbon fiber of the present invention is characterized in that a precursor fiber formed from a polymer solution obtained by mixing fine particles of a specific type, an average particle size and a content in a polymer before spinning is fired, It has the following excellent effects.

(1)耐炎化工程での融着を防止することのみならず、前
駆体繊維紡糸時の融着をも防止でき、高品質の炭素繊維
を工業的に生産性良く製造することができる。(1) Not only the fusion in the flameproofing step can be prevented but also the fusion in the precursor fiber spinning can be prevented, and high-quality carbon fibers can be industrially produced with high productivity.

(2)上記融着防止効果は、繊維束の構成本数に関係なく
効果がある。(2) The fusion preventing effect is effective regardless of the number of constituent fiber bundles.

(3)さらには、微粒子の融着防止効果により、前駆体繊
維の紡糸時に付与される必要油剤量を低減できる。その
ために耐炎化工程でのタール汚れが改善され糸切れが減
少する。(3) Furthermore, due to the effect of preventing the fusion of the fine particles, the amount of necessary oil agent applied during spinning of the precursor fiber can be reduced. Therefore, tar stains in the flameproofing process are improved and yarn breakage is reduced.

また，タール汚れのために実施される耐炎化炉の定期修
理の回数も減少しさらには排ガス処理が容易になるなど
の効果があり、工業的生産性が著しく向上する。In addition, the number of regular repairs of the flameproof furnace due to tar contamination is reduced, and further, exhaust gas treatment is facilitated, and industrial productivity is significantly improved.

以下、本発明を実施例により説明する。Hereinafter, the present invention will be described with reference to examples.

実施例１，比較例１ 黒鉛粒子を分別をくり返し第１表に示す平均粒子径の微
粒子を得た。Example 1, Comparative Example 1 Graphite particles were repeatedly separated to obtain fine particles having an average particle size shown in Table 1.

アクリロニトリル９９．５モル％およびイタコン酸０．
５モル％をジメチルスルホキシド（ＤＭＳＯ）の溶媒中
で重合するに際し、得られる最終ポリマー量に対し５０
０ｐｐｍになるように該微粒子を混入させ２５時間かけ
て重合を行なつた。また該微粒子を混入しない水準も同
様に重合を行なつた。Acrylonitrile 99.5 mol% and itaconic acid 0.
When polymerizing 5 mol% in a solvent of dimethylsulfoxide (DMSO), 50% of the final polymer amount obtained was used.
The fine particles were mixed so as to be 0 ppm, and polymerization was carried out for 25 hours. Further, the polymerization was carried out in the same manner even when the fine particles were not mixed.

得られた紡糸原液は、いずれもポリマー濃度１９．０ｗ
ｔ％であり、４５℃での粘度は７５０ポイズであつた。The obtained spinning dope has a polymer concentration of 19.0 w.
%, and the viscosity at 45 ° C. was 750 poise.

上記紡糸原液を直径０．１２mm，ホール数１５００の紡
糸口金を通し、一旦空気中に吐出させる乾−湿式紡糸法
により３mmの空間を通過させた後に、５５％のＤＭＳＯ
水溶液中で凝固させ、次いで水洗後に８０℃の温水中で
３．５倍に延伸し、水膨潤糸条を得た。The spinning solution was passed through a spinneret having a diameter of 0.12 mm and a number of holes of 1500, and was once discharged into the air by a dry-wet spinning method to pass through a space of 3 mm, and then 55% DMSO.
It was solidified in an aqueous solution, washed with water, and then stretched 3.5 times in warm water at 80 ° C. to obtain a water-swelled yarn.

この膨潤糸条に付着量が０．５ｗｔ％になるように油剤
を付与し表面温度が１３０℃のホットローラー上で乾燥
緻密化させ、次いで加圧チチーム中で２倍に延伸し、単
糸デニール１ｄ，トータルデニールが３０００Ｄの前駆
体繊維を得た。An oil agent was applied to the swollen yarn so that the adhered amount was 0.5% by weight, and the mixture was dried and densified on a hot roller having a surface temperature of 130 ° C., and then stretched twice in a pressurized team, to obtain a single yarn denier. A precursor fiber having 1d and a total denier of 3000D was obtained.

この前駆体繊維束の強伸度をテンシロンＵＴＭ−III型
で測定した結果を第１表に示す。なお強伸度はｎ＝１５
の平均値を示す。Table 1 shows the results of measuring the strength and elongation of this precursor fiber bundle using Tensilon UTM-III type. Note that the toughness is n = 15
The average value of is shown.

該前駆体繊維のそれぞれについて２２０℃から２５０℃
まで段階的に温度を上げながら加熱空気中で耐炎化処理
後、１４００℃のチツ素雰囲気下で炭化処理を行なつ
た。220 ° C to 250 ° C for each of the precursor fibers
After the flameproofing treatment in the heated air while gradually raising the temperature, the carbonization treatment was performed in a nitrogen atmosphere at 1400 ° C.

得られた炭素繊維にエポキシ樹脂を含浸させ、硬化後、
テンシロンを用いて強度，弾性率を測定した（ｎ＝１０
の平均値）。その結果を第１表に示す。The obtained carbon fiber is impregnated with an epoxy resin, and after curing,
Strength and elastic modulus were measured using Tensilon (n = 10
Average value). The results are shown in Table 1.

第１表に示す範囲の微粒子の混入においては、前駆体繊
維の強伸度にはほとんど差は認められなかつたが、焼成
後の炭素繊維の強度には差が認められ、本発明の効果は
明らかである。 In mixing the fine particles in the range shown in Table 1, there was almost no difference in the strength and elongation of the precursor fiber, but there was a difference in the strength of the carbon fiber after firing, and the effect of the present invention is it is obvious.

サンプルNO.1は前駆体繊維の融着は認められず紡糸工程
の通過安定性は良好であり、耐炎化工程かではわずかに
融着が認められたが比較的高強度の炭素繊維が得られ
た。サンプルNO.4は紡糸工程，耐炎化工程を通じてわず
かに毛羽の発生が認められたが融着の問題はなく、比較
的強度の高い炭素繊維が得られた。In sample No. 1, no fusion of the precursor fiber was observed, the passage stability in the spinning process was good, and a slight fusion was observed in the flameproofing process, but a relatively high strength carbon fiber was obtained. It was In sample No.4, fluff was slightly generated during the spinning process and flameproofing process, but there was no problem of fusion and carbon fiber of relatively high strength was obtained.

サンプルNO.5は紡糸工程，耐炎化工程を通じて融着は認
められなかつたが、粒子径が大きすぎるために毛羽の発
生が著しく、炭素繊維の強度が著しく低下した。サンプ
ルNO.6は紡糸工程，耐炎化工程での毛羽，融着が多く認
められ、また炭化工程での糸切れのトラブルが多く炭素
繊維の強度も低かった。No fusion was observed in Sample No. 5 through the spinning process and the flameproofing process, but the particle size was too large, so that fluff was significantly generated and the strength of the carbon fiber was significantly reduced. In sample No.6, many fluffs and fusion were observed in the spinning process and flame resistance process, and there were many yarn breakage problems in the carbonization process, and the carbon fiber strength was low.

実施例２ 実施例１で得られたサンプルNO.3の前駆体繊維を第３表
に示すように合糸本数を変え、実施例１と同様に耐炎
化，炭化処理を行なつた後、炭素繊維にエポキシ樹脂を
含浸させた硬化後、テンシロンを用いて強度，弾性率を
測定した。その結果を第２表に示す。Example 2 The precursor fiber of sample NO.3 obtained in Example 1 was subjected to flame resistance and carbonization treatment in the same manner as in Example 1, except that the number of yarns was changed as shown in Table 3, and then carbon was added. After the fiber was impregnated with an epoxy resin and cured, the strength and elastic modulus were measured using Tensilon. The results are shown in Table 2.

本発明の効果は、繊維構成本数によらず有効であること
が明らかである。 It is clear that the effect of the present invention is effective regardless of the number of fiber constituents.

実施例３，比較例２ 実施例１において重合するに際し平均粒子径が０．０７
μの黒鉛微粒子を最終ポリマー量に対し５００ppm にな
るように混入し、紡糸時に油剤付着量を変えた他は実施
例１と同様にして前駆体繊維を得た。Example 3, Comparative Example 2 In the polymerization in Example 1, the average particle size was 0.07.
Precursor fibers were obtained in the same manner as in Example 1 except that fine graphite particles of μ were mixed so as to be 500 ppm with respect to the final polymer amount, and the amount of the oil agent adhered during spinning was changed.

また、比較例として該微粒子を混入することなく、紡糸
時に油剤付着量を変えた他は実施例１と同様にして前駆
体繊維を得た。Further, as a comparative example, a precursor fiber was obtained in the same manner as in Example 1 except that the amount of the oil agent adhered during spinning was changed without mixing the fine particles.

これらの前駆体繊維を実施例１と同様に焼成ならびに硬
化処理し、テンシロンを用いて強度，弾性率を測定し
た。その結果を第３表に示す。These precursor fibers were fired and cured as in Example 1, and the strength and elastic modulus were measured using Tensilon. The results are shown in Table 3.

油剤付着量が多いサンプルほど耐炎化炉のタール汚れが
多く認められ、実施例は比較的少ない油剤付着量で高強
度の炭素繊維を得ることができるため、耐炎化炉のター
ル汚れも減少できることが明らかである。 The larger the amount of oil agent adhered, the greater the amount of tar stains in the flameproof furnace, and in the examples, since carbon fibers of high strength can be obtained with a relatively small amount of oil agent adhered, tar stains in the flameproof furnace can also be reduced. it is obvious.

実施例４ 実施例１に用いたポリマーにおいて黒鉛微粒子を混合せ
ずに重合を行なった後、平均粒径０．３６μｍの酸化チ
タンのＤＭＳＯ分散液を加えた紡糸原液を調製し、これ
を用いて実施例１と同様に紡糸することにより、ポリマ
ー中の酸化チタン含有量が１０００ｐｐｍ、単糸デニー
ル１ｄ，トータルデニールが３０００Ｄの前駆体繊維を
得た。Example 4 The polymer used in Example 1 was polymerized without mixing graphite fine particles, and then a DMSO dispersion liquid of titanium oxide having an average particle diameter of 0.36 μm was added to prepare a spinning dope solution. By spinning in the same manner as in Example 1, a precursor fiber having a titanium oxide content of 1000 ppm in the polymer, a single yarn denier of 1 d and a total denier of 3000 D was obtained.

これを実施例１と同様に焼成を行なったところ、毛羽が
なく、強度２８０ kg/mm^２、弾性率２６．３t/mm^２の炭
素繊維糸条を得た。When this was fired in the same manner as in Example 1, a carbon fiber yarn having no fluff, a strength of 280 kg / mm ² , and an elastic modulus of 26.3 t / mm ² was obtained.

実施例５ 実施例４の酸化チタンに代えて、平均粒径０．０５μｍ
の二酸化ケイ素を加えた紡糸原液を調製し、これを用い
て実施例１と同様に紡糸することにより、ポリマー中の
二酸化ケイ素含有量が５０００ｐｐｍ、単糸デニール１
ｄ，トータルデニールが３０００Ｄの前駆体繊維を得
た。Example 5 Instead of the titanium oxide of Example 4, an average particle size of 0.05 μm
A spinning solution containing silicon dioxide was prepared and spinning was carried out in the same manner as in Example 1 to give a polymer having a silicon dioxide content of 5000 ppm and a single yarn denier of 1
d, a precursor fiber having a total denier of 3000 D was obtained.

これを実施例１と同様に焼成を行なったところ、毛羽が
なく、強度２５１ kg/mm^２、弾性率２５．９t/mm^２の炭
素繊維糸条を得た。When this was fired in the same manner as in Example 1, a carbon fiber yarn having no fluff, a strength of 251 kg / mm ² , and an elastic modulus of 25.9 t / mm ² was obtained.

───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特公 昭52−39455（ＪＰ，Ｂ１) ─────────────────────────────────────────────────── ─── Continuation of front page (56) References Japanese Patent Publication Sho 52-39455 (JP, B1)

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】平均粒子径０．０１〜０．３５μの黒鉛微
粒子を含有したアクリル系ポリマーの紡糸原液を用いて
紡糸を行なうことによって、該微粒子を１００〜１００
０ｐｐｍの範囲内で繊維を構成するポリマー中に含有す
る炭素繊維製造用アクリル系前駆体繊維を得、これを焼
成することを特徴とする炭素繊維の製造方法。1. Fine particles of 100 to 100 are obtained by spinning using an acrylic polymer spinning stock solution containing fine graphite particles having an average particle diameter of 0.01 to 0.35 μm.
A method for producing a carbon fiber, which comprises obtaining an acrylic precursor fiber for producing a carbon fiber contained in a polymer constituting the fiber within a range of 0 ppm and calcining the obtained fiber.