JPS58115123A - Surface treatment of carbon fiber - Google Patents

Abstract

PURPOSE:A porous diaphragm is set between the carbon fiber yarns running in the electrolyte solution and the cathode plate and the carbon fibers are used as the anode to effect the electrolytic treatment on their surfaces, thus permitting uniform electrolytic treatment of the carbon fiber bundle in large amounts. CONSTITUTION:A porous diaphragm 5, e.g., a material which is chemically inert to the electrolyte, metal mesh, carbon fiber cloth or clay plate, is set between the carbon fiber bundle 2 running in the electrolysis tank 1 in the arrow direction and the cathode plate 4 in the tank 1. Then, electric current is sent from the source 6 to make the carbon fiber bundle 2 act as the anode with the terminal 3 for anode and oxidize the surface of the carbon fibers with the nascent oxygen formed by the electrolytic reaction. The carbon fiber bundle consists of 500-200,000 carbon fibers and it is preferred to treatmore than 50 fibers electrolytically at a time.

Description

【発明の詳細な説明】 本発明は表面電解処理効率にすぐれた炭素繊維の表面処
理法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carbon fiber surface treatment method with excellent surface electrolytic treatment efficiency.

再生セルロース、ポリアクリロニトリル、ピッチなどか
らなる繊維を酸化熱処理し、炭素化乃至黒鉛化すること
によって得られる炭素繊維はその高強度、高弾性率、特
に比強度、比弾性率が大きいという力学的特性に基づき
、複合材料（コンポジット）の補強用繊維として極めて
優れた性能を有する。この炭素繊維を補強用繊維とする
複合材料は航空、宇宙用途或いは自動車、船舶等の輸送
機械における軽量化もしくは燃費低減の要請から、それ
らの構造材料として広く、大量に使用されようとしてい
る。Carbon fibers obtained by subjecting fibers made of regenerated cellulose, polyacrylonitrile, pitch, etc. to oxidative heat treatment and carbonization or graphitization have mechanical properties such as high strength and high modulus, especially high specific strength and specific modulus. Based on this, it has extremely excellent performance as a reinforcing fiber for composite materials. Composite materials using carbon fibers as reinforcing fibers are being used widely and in large quantities as structural materials for aviation and space applications, as well as for transportation machinery such as automobiles and ships, in response to demands for weight reduction and fuel consumption reduction.

しかしながら、炭素繊維の秀れた力学的性質を複合材料
に十分反吠させるためには複合材料の母材（マトリック
ス）と炭素繊維とが十分に接着し一体化する必要がある
が一般に炭素繊維からの〃すめけ〃が起り易く、複合材
料としての曲げあるいは剪断強度が低くなり十分な補強
効果を発揮しない。However, in order to fully utilize the excellent mechanical properties of carbon fibers in composite materials, it is necessary for the base material (matrix) of the composite material and carbon fibers to sufficiently adhere and integrate. The bending or shearing strength of the composite material becomes low and it does not exhibit sufficient reinforcing effect.

そこで、従来から炭素繊維には酸化剤による湿式酸化処
理、ヒートクリーニング、気相酸化。Therefore, carbon fiber has traditionally been treated with wet oxidation treatment using an oxidizing agent, heat cleaning, and gas phase oxidation.

ウィスカライジングおよび電解処理などの各種の表面処
理が施されているが、これらの中でも電気分解により陽
極に酸素を生成する電解質溶液中で炭素繊維を陽極とし
て炭素繊維を電解酸化処理する。方法が、その簡便性、
並びに強度低下が少ないという利点から広く採用されて
いる。Various surface treatments such as whiskerizing and electrolytic treatment are performed, and among these, the carbon fiber is electrolytically oxidized using the carbon fiber as an anode in an electrolyte solution that generates oxygen at the anode by electrolysis. The method is simple,
It has also been widely adopted because of its advantages of little reduction in strength.

しかるに、この炭素繊維の表面電解処理において、単糸
繊維本数の多い炭素繊維束を複数本同時に電解処理する
と、炭素繊維束間もしくは繊維束を構成する単糸間にお
ける表面処理が不均一化し易く、最終製品の複合材料の
力学的性質に影響を及ぼすことが判明した。すなわち、
炭素繊維の表面電解処理においては電解液中を陽極とし
て走行す木炭素繊維表面で発生期の酸素が発生し、他方
電解液中の陰極では電解質のイオン種によって異なるが
各種の気体たとえば水素やアンモニアなどが発生する。However, in this surface electrolytic treatment of carbon fibers, if multiple carbon fiber bundles having a large number of single fibers are electrolytically treated at the same time, the surface treatment between the carbon fiber bundles or between the single fibers constituting the fiber bundles tends to become uneven. It was found to influence the mechanical properties of the composite material in the final product. That is,
In the surface electrolytic treatment of carbon fibers, nascent oxygen is generated on the surface of the wood carbon fibers running in the electrolyte as an anode, while at the cathode in the electrolyte various gases such as hydrogen and ammonia are generated, depending on the ion type of the electrolyte. etc. occur.

この陰極で発生する気体は炭素繊維表面の酸化に対して
は効果を示さないばかりでなく、電解液中で気泡となっ
て上昇し、炭素繊維表面に捕捉されると泡が付着した部
分だけは電流が流れなくなり、炭素繊維表面の電解処理
を不均一化するのであるＯ このような陰極から発生する気体による表面電解処理の
不均一化を防止する←恰←方法として、特公昭５６−１
７４６５号公報には、上記電解処理を分解電圧以下で行
ない、陽極および陰極からの気体の発生そのものを防止
する方法が開示されているが、この方法は炭素繊維の表
面電解が不十分になるだけでなく、電解処理能力を低下
させ工業的な方法ではない。The gas generated at this cathode not only has no effect on the oxidation of the carbon fiber surface, but also rises as bubbles in the electrolyte and is trapped on the carbon fiber surface. This prevents the current from flowing and makes the electrolytic treatment on the surface of the carbon fiber non-uniform.To prevent such non-uniform surface electrolytic treatment due to the gas generated from the cathode, a method was proposed in Japanese Patent Publication No. 56-1.
Publication No. 7465 discloses a method in which the above-mentioned electrolytic treatment is performed below the decomposition voltage to prevent the generation of gas from the anode and cathode, but this method only results in insufficient surface electrolysis of the carbon fiber. However, it is not an industrial method as it reduces the electrolytic treatment capacity.

さらに、大量の′炭素繊維の表面電解処理を行うために
は、単糸本数の多い炭素縁Ｘｅ複数本へ 同時に電解処理することが望まれるが、単糸本数数の多
い炭素繊維束を複数本特に数十率の繊維束を一挙に電解
処理するときは陰極から発生する気体が該炭素繊維束の
内外部に大量にかつ不均一に付着し、効率的電解酸化が
著しく難かしくなり、処理能力は必ずしも向上しないし
、この付着した気泡を除去する。ために、炭素繊維束を
振動させたり、電解液を攪拌したりすると電解処理時に
炭素繊輯束に毛羽が生じたり、単糸孔れが大きくなり開
繊性が損われるという問題があることが判明した。Furthermore, in order to perform surface electrolytic treatment on a large amount of carbon fibers, it is desirable to electrolytically treat multiple carbon edge Xe fibers with a large number of single fibers at the same time. In particular, when several tens of fiber bundles are electrolytically treated at once, a large amount of gas generated from the cathode adheres unevenly to the inside and outside of the carbon fiber bundle, making efficient electrolytic oxidation extremely difficult and reducing processing capacity. However, removing the attached air bubbles will not necessarily improve the results. Therefore, if the carbon fiber bundle is vibrated or the electrolyte is stirred, there may be problems such as fluffing of the carbon fiber bundle during electrolytic treatment, enlargement of single fiber holes, and loss of opening properties. found.

本発明の目的は上記欠点のない改良された炭素繊維束の
表面電解処理法、特に単糸本数の多い炭素繊維束を多数
本同時に電解処理し、かつ均一で斑のない炭素繊維束の
電解処理法を提供束 するにある。さらに他の目的は炭素繊維め電解＾ 処理における陰極からの電気絶縁性気体による悪影響が
なく、大量の炭素繊維を処理することがで市る電解処理
法を提供するにある。このような本発明の目的は前記特
許請求の範囲に記載した発明により達成することができ
る。The object of the present invention is to provide an improved surface electrolytic treatment method for carbon fiber bundles that does not have the above-mentioned drawbacks, and in particular to electrolytically treat a large number of carbon fiber bundles having a large number of single yarns at the same time, and to electrolytically treat carbon fiber bundles that are uniform and free from unevenness. The law is in a bundle. Another object of the present invention is to provide an electrolytic treatment method that is free from the adverse effects of electrically insulating gas from the cathode during the electrolytic treatment of carbon fibers and is capable of treating a large amount of carbon fibers. Such objects of the present invention can be achieved by the invention described in the claims.

本発明の特徴は前記炭素繊維の表面電解処理において電
解液中を走行′する炭素繊維と同じく電解液中に該炭素
繊維に対して相対的に設置された陰極板との間に多孔質
の隔壁を設けて電解処理することにある。A feature of the present invention is that in the surface electrolytic treatment of carbon fibers, a porous partition wall is provided between the carbon fibers running in the electrolyte and a cathode plate placed relative to the carbon fibers in the electrolyte. The purpose is to provide an electrolytic treatment.

処理することにある。It's about processing.

ここで、前記多孔質の隔壁は電解質に対して化学的に安
定な素材、たとえば金網、炭素繊維布、耐炎化繊維布、
素焼板１石綿製の紙や布。Here, the porous partition wall is made of a material that is chemically stable to the electrolyte, such as wire mesh, carbon fiber cloth, flame-resistant fiber cloth,
Unglazed board 1 Paper or cloth made of asbestos.

綿布１合成繊維製布帛な′どがあり、これらの素材から
なる隔壁は電解により発生したイオンはもちろん、電解
液を自由に通過させる多孔構造・好ましくは空孔率がＯ
，ｌ−０，６の範囲内の板状体がよい。隔壁の素材が電
気的に導電性の金属製金網や炭素繊維などの場合は電解
槽で絶縁しておく必要があり、この隔壁そのものが電気
的に導通していると炭素繊維自体の表面電解が妨げられ
るからである。There are cotton cloth 1 synthetic fiber cloth, etc., and the partition wall made of these materials has a porous structure that allows not only ions generated by electrolysis but also the electrolyte to freely pass through, preferably with a porosity of O.
, l-0,6 is preferable. If the material of the partition wall is electrically conductive metal wire mesh or carbon fiber, it must be insulated with an electrolytic bath, and if the partition wall itself is electrically conductive, the surface electrolysis of the carbon fiber itself will occur. Because it will be hindered.

また、隔壁の位置は特に限定されないが、電解液中の陰
極板と走行する炭素繊維束とのほぼ中間、好ましくは中
間より陰極板に近い位置に設けるのがよく、このような
位置に隔壁を設けることにより陰極で発生するガスをよ
り効率的に捕捉することができる。なお隔壁の厚さは陰
極板からの発生ガスを十分に捕捉する限りにおいてでき
るだけ薄くシ、電解槽全体としての電気抵抗が増大しな
いようにするのがよい。Further, the location of the partition wall is not particularly limited, but it is preferable to provide the partition wall approximately midway between the cathode plate in the electrolyte and the running carbon fiber bundle, preferably at a position closer to the cathode plate than the middle. By providing this, gas generated at the cathode can be captured more efficiently. The thickness of the partition wall is preferably as thin as possible so long as it can sufficiently capture the gas generated from the cathode plate, so as not to increase the electrical resistance of the electrolytic cell as a whole.

本発明において、複数本の炭素繊維束を処理する場合に
は隔壁と陰極板とをそれぞれ複′数ケ互いに相対せしめ
て、がっ、電解液中を走行する炭素繊維束がこれらに相
対する慢隔壁と陰極板の上方に来ないように配置するこ
とにより、前述した陰極板から発生するガスが炭素繊維
束に捕捉されるのを有効に防止することが可能になる。In the present invention, when treating a plurality of carbon fiber bundles, a plurality of partition walls and a plurality of cathode plates are made to face each other, so that the carbon fiber bundles running in the electrolyte have a high speed facing them. By arranging it so as not to be above the partition wall and the cathode plate, it becomes possible to effectively prevent the gas generated from the cathode plate described above from being trapped in the carbon fiber bundle.

すなわち、陰極板から発生するガスは電解液中を上昇し
、該陰極板に相対して配置された隔壁に捕捉され、この
隔壁で捕捉され、成長したガスは浮力を増大して隔壁か
ら離脱して液中を再び上昇し、走行する炭素繊維束と炭
素繊維束の間隙から炭素繊維束に接触することなく、槽
外に放出されるのである。That is, the gas generated from the cathode plate rises in the electrolytic solution and is captured by the partition wall placed opposite to the cathode plate, and the gas that grows increases its buoyancy and leaves the partition wall. The carbon fibers rise again in the liquid and are discharged from the gap between the traveling carbon fiber bundles to the outside of the tank without coming into contact with the carbon fiber bundles.

電解処理に用いる電解液としては、たとえばナトリウム
、アンモニア水などの塩基等の公知以下、本発明を図面
により具体的に説明する。Examples of the electrolytic solution used in the electrolytic treatment include bases such as sodium and aqueous ammonia.The present invention will be specifically described below with reference to the drawings.

第１図は本発明に用いる炭素繊維の表面電解処理槽の１
例を示す模式断面図であり、図において（１）は電解槽
、（２）は炭素繊維束、（３）は陽極電流入力端子、（
４）は陰極板、（５）は＠壁板、（６）は電源である。Figure 1 shows one of the carbon fiber surface electrolysis treatment tanks used in the present invention.
It is a schematic cross-sectional view showing an example, in which (1) is an electrolytic tank, (2) is a carbon fiber bundle, (3) is an anode current input terminal, (
4) is the cathode plate, (5) is the @wall plate, and (6) is the power source.

図に示すように、電解液で満たされた電解槽（１）には
循環ポンプ（図示せず）によって電解液が循環され、槽
の両端から電解液がオーバーフ四−シている。炭素繊維
束（２）はこの電解槽（１）中を矢印方向に連続的に走
行する。炭素繊維束（２）は陽極電流入力端子によって
電解液中では陽性として機能し、該電解液中を走行する
間に電解反応によって発生した発生期の階素により表面
を酸化される。As shown in the figure, the electrolytic solution is circulated in an electrolytic cell (1) filled with electrolytic solution by a circulation pump (not shown), and the electrolytic solution overflows from both ends of the cell. The carbon fiber bundle (2) runs continuously in the direction of the arrow in this electrolytic cell (1). The carbon fiber bundle (2) functions as a positive electrode in the electrolyte through the anode current input terminal, and its surface is oxidized by nascent particles generated by an electrolytic reaction while traveling in the electrolyte.

他方、陰極板（４）で憾陽イオン、たとえば水素゛イオ
ンが電荷を失ないガスとなって電解液中を上方に上昇し
、このガスは陰極板（４）上部に配置された隔壁板（５
）に捕捉される。この隔壁板（５）に捕捉されたガスは
次第に成長して浮力を増大すると、該隔壁板（５）を離
れて気泡として上昇するが、この気泡は走行する炭素繊
維束に接触しても、その浮力が大きいためにもはや繊維
束に捕捉されることなく上昇を続け、ついには電解液表
面から空中に散逸する。On the other hand, at the cathode plate (4), negative ions, such as hydrogen ions, become a gas that does not lose its charge and rise upward in the electrolyte, and this gas passes through the partition plate (4) disposed above the cathode plate (4). 5
) is captured. As the gas trapped in the partition plate (5) gradually grows and increases its buoyancy, it leaves the partition plate (5) and rises as bubbles, but even if these bubbles come into contact with the traveling carbon fiber bundle, Because of its large buoyancy, it continues to rise without being captured by the fiber bundle, and eventually dissipates into the air from the surface of the electrolyte.

第２図（イ）および、（ロ）は本発明に用いる電解槽の
他の実施態様を示す断面図であり、（１）〜（７）はそ
れぞれ同様に電解槽、炭素繊維束、陽性電流大型とし、
この隔壁板に捕捉された気体を隔壁板法を炭素繊維束（
２）の巾よりも大きくしたものである。、通常隔壁板を
介在させると隔壁板に補足されたガスは隔壁板の縁辺か
ら気泡（））となって液中を上昇し、液外に散逸するの
で、第２図（ロ）に示すような隔壁板を用いることによ
り、液中を上昇する気泡（））を炭素繊維束に接触する
のを防ぐことができる。FIGS. 2(a) and 2(b) are cross-sectional views showing other embodiments of the electrolytic cell used in the present invention, and (1) to (7) respectively show the electrolytic cell, carbon fiber bundle, and positive current. Large size,
The gas trapped in this partition plate is transferred to carbon fiber bundles (
It is larger than the width of 2). Normally, when a partition plate is interposed, the gas captured by the partition plate becomes bubbles () from the edge of the partition plate, rises in the liquid, and dissipates out of the liquid, as shown in Figure 2 (b). By using a bulkhead plate, it is possible to prevent bubbles rising in the liquid from coming into contact with the carbon fiber bundle.

本発明によれば大量の炭素繊維束を均一に電解処理する
ことができ、特に５００〜２００，０００本の単繊維か
らなる連続炭素繊維−４４４束を５０〜５００本同時に
電同時理する際に陰極板から発生する大量の電気絶縁性
気体に起因する電解処理の不均一化を防止することがで
き、マトリックス樹脂に対する接着性の良好な炭素繊維
束、ひいては品質、性能、の安定した複合材料の提供を
可能とする。のである。According to the present invention, it is possible to uniformly electrolytically treat a large amount of carbon fiber bundles, especially when electrolytically treating 50 to 500 continuous carbon fiber-444 bundles consisting of 500 to 200,000 single fibers at the same time. It is possible to prevent non-uniform electrolytic treatment caused by a large amount of electrically insulating gas generated from the cathode plate, and it is possible to create a carbon fiber bundle with good adhesion to the matrix resin, resulting in a composite material with stable quality and performance. It is possible to provide It is.

以下、実施例により本発明の効果の１例を示す。EXAMPLES Hereinafter, one example of the effects of the present invention will be shown with reference to Examples.

実施例１ アクリル繊維を出発物質として常法により６０００フイ
ラメントから成る炭素繊維を得た。Example 1 A carbon fiber consisting of 6000 filaments was obtained by a conventional method using acrylic fiber as a starting material.

該繊維を２００本平行に走行させ図１に例示した電解槽
を用いて炭素繊維を陽極として表面処理を行った。！解
液にはＯ，Ｘ規定の硫酸を用い印加電圧は１５Ｖであっ
た。電解槽・中に本発明の方法に従って隔壁を設けた場
合とそうでもなイ場合についてコンポジットにおける層
間剪断強度（工ＬＢＥＪ慶評価しそのｉ果を第１に示し
た。200 of these fibers were run in parallel and surface treatment was performed using the electrolytic cell illustrated in FIG. 1 with the carbon fibers as anodes. ! Sulfuric acid with O and X standards was used as the solution, and the applied voltage was 15V. The interlaminar shear strength (LBEJ Kei) of the composite was evaluated for cases in which partition walls were provided according to the method of the present invention in the electrolytic cell and cases in which partition walls were not provided in the electrolytic cell according to the method of the present invention.

なお、ここで用いた隔壁は２００メツシユのステンレス
製金網、より成るもので、有孔率０．３６であった。本
隔壁を用いても同一電圧で電流の低下は認められず抵抗
の増加は無視出来ることはＳ認された。The partition wall used here was made of a 200-mesh stainless steel wire mesh, and had a porosity of 0.36. S acknowledged that even if this barrier rib was used, no decrease in current was observed at the same voltage, and the increase in resistance could be ignored.

表　　　　　１ 上表中工ＬＳＳ変動幅とは２００糸条よりランダムに５
０糸条抜き出して工Ｌ’ｓｓを測定した時の最高値と最
小値の差である。隔壁の使用により変動幅を減少させる
ことが出来ることが明らかとなった。Table 1 The above table shows the intermediate work LSS fluctuation range. Randomly 5 out of 200 yarns
This is the difference between the highest value and the lowest value when measuring L'ss after extracting 0 yarns. It has become clear that the fluctuation range can be reduced by using partition walls.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図および第２図（イ）、（ロ）はそれぞれ本発明に
用いる炭素繊維束の電解処理槽の１例を示す模式断面図
である。 （１）；電解槽　　　　　（２）：炭素繊維束（８）：
陽極電流大刀端子　（４）：陰極板（５）：隔壁　　　
　　　　（８）　：　Ｍ源特許出願人　東し株式会社FIG. 1 and FIGS. 2(A) and 2(B) are schematic cross-sectional views showing one example of an electrolytic treatment tank for carbon fiber bundles used in the present invention. (1); Electrolytic cell (2): Carbon fiber bundle (8):
Anode current long terminal (4): Cathode plate (5): Partition wall
(8): M Gen patent applicant Toshi Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] （１）　　炭素繊維を陽極として表面電解処理するに際
して、電解液中を走行する炭素繊維糸条と電解槽中の陰
極板との間に多孔質の隔壁を設けて表面電解処理するこ
とを特徴とする炭素繊維の表面処理法。 （２、特許請求の範囲第１項において、炭素繊維が５０
０〜２００，０００本の単繊維からなる炭素繊維束であ
り、この炭素繊維束を少くとも５０本同時に電解処理す
ることを特徴とする炭素繊維の表面処理法。(1) When performing surface electrolytic treatment using carbon fiber as an anode, the surface electrolytic treatment is performed by providing a porous partition between the carbon fiber thread running in the electrolytic solution and the cathode plate in the electrolytic cell. Carbon fiber surface treatment method. (2. In claim 1, carbon fiber contains 50%
A method for surface treatment of carbon fibers, which is a carbon fiber bundle consisting of 0 to 200,000 single fibers, characterized in that at least 50 carbon fiber bundles are electrolytically treated at the same time.