JP2017172081A

JP2017172081A - Method for producing acrylonitrile-based fiber bundle and method for producing carbon fiber bundle

Info

Publication number: JP2017172081A
Application number: JP2016061336A
Authority: JP
Inventors: 拓哉長坂; Takuya Nagasaka; 博義生田; Hiroyoshi Ikuta; 祥二船越; Shoji Funakoshi; 達也花輪; Tatsuya Hanawa
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2016-03-25
Filing date: 2016-03-25
Publication date: 2017-09-28
Anticipated expiration: 2036-03-25
Also published as: JP6558288B2

Abstract

PROBLEM TO BE SOLVED: To provide a method which can stably produce a high-quality acrylonitrile-based fiber bundle while increasing a filament running velocity or increasing the number of holes in a spinneret, in dry-wet spinning.SOLUTION: In a method for producing an acrylonitrile-based fiber bundle, a spinning dope is once extruded from a spinneret into air, and is then introduced downward into a coagulation bath to which a coagulation bath liquid is supplied upward from a coagulation bath liquid inflow port disposed in a bottom surface, thereby forming coagulated filaments. The coagulated filaments are turned up at a direction changing guide disposed in the coagulation bath below the spinneret, and are drawn out to the outside of the coagulation bath. 60% or more of the flow directions of the coagulation bath liquid at respective positions which are 35 mm apart from a spinneret outer circumferential part, and which equally make at least 10 divisions in a circumference direction equally apart from a spinneret center, at a depth of 40 mm from a coagulation bath liquid surface, are directions toward the spinneret. The average of the absolute values of the flow velocities of the coagulation bath liquid is 0.8 m/min or higher.SELECTED DRAWING: Figure 2

Description

本発明は、炭素繊維束の製造方法に適した、安定して高品位のアクリロニトリル系繊維束を製造する方法に関する。 The present invention relates to a method for producing a stable and high-quality acrylonitrile fiber bundle suitable for a method for producing a carbon fiber bundle.

炭素繊維の前駆体繊維などとして用いられるアクリロニトリル系繊維束の製造においては、生産効率を高め、そして製造原価を低減させることが重要である。この要求に応えるため、一錘当たりの孔数を増加させた紡糸口金や、口金錘数・糸条数を増加させる方法、更には糸条走行速度を増大させる方法等、多種多様の方法が採用されている。これらの方法のうち、口金一錘当たりの孔数を増加させたり、糸条走行速度を増加させたりすることは、大幅な設備投資を伴わずに要求に応えることができる点で大きな利点がある。 In the manufacture of acrylonitrile fiber bundles used as carbon fiber precursor fibers, it is important to increase production efficiency and reduce manufacturing costs. To meet this demand, a wide variety of methods are used, such as a spinneret with an increased number of holes per spindle, a method of increasing the number of spindles and yarns, and a method of increasing the yarn running speed. Has been. Of these methods, increasing the number of holes per die and increasing the yarn traveling speed has a great advantage in that it can meet the demand without significant capital investment. .

しかしながら、アクリロニトリル系繊維束の製造において、アクリロニトリル系ポリマーを含んだ紡糸原液を口金面から一旦空気中に押し出した後、凝固浴中に下向きに吐出し、方向転換ガイドで折り返して凝固浴外に引き出す乾湿式紡糸法を採用する場合、凝固浴中の糸条走行速度を増加させると、得られるアクリロニトリル系繊維束の品位が著しく悪化し、糸切れ等の操業性の悪化を伴うことが多い。 However, in the production of acrylonitrile fiber bundles, the spinning stock solution containing the acrylonitrile polymer is once extruded into the air from the die surface, then discharged downward into the coagulation bath, folded back with a direction change guide, and drawn out of the coagulation bath. When the dry and wet spinning method is employed, if the yarn traveling speed in the coagulation bath is increased, the quality of the resulting acrylonitrile fiber bundle is remarkably deteriorated, often accompanied by deterioration of operability such as yarn breakage.

そこで、特許文献１には紡糸原液を直接凝固浴中に吐出し凝固浴外に引き出す湿式紡糸法において、紡出糸条と凝固浴底面の間に仕切板を配置することで、糸条走行速度を高めても凝固浴内での糸条の乱れや、絡まりの原因となる凝固浴液の乱れを抑制する技術が開示されている。また、同じく湿式紡糸法において、紡出糸条と凝固浴底面の間に開口を有する整流板を配置する技術によっても、同様の効果を発揮することが知られている（特許文献２参照）。 Therefore, in Patent Document 1, in the wet spinning method in which the spinning solution is directly discharged into the coagulation bath and drawn out of the coagulation bath, a partition plate is disposed between the spun yarn and the bottom of the coagulation bath, so that the yarn traveling speed is increased. A technique for suppressing disturbance of the yarn in the coagulation bath and disturbance of the coagulation bath liquid that causes entanglement even if the height is increased is disclosed. Similarly, in the wet spinning method, it is also known that the same effect is exhibited by a technique of arranging a current plate having an opening between the spun yarn and the bottom of the coagulation bath (see Patent Document 2).

しかしながら、これらの技術は、湿式紡糸法では大きな効果を発揮するが、乾湿式紡糸法においては、単に紡出糸条と凝固浴底面との間に仕切板や整流板を配置するだけでは、凝固浴液の乱れを十分に抑制することがこれまで不可能であった。この理由として、凝固浴はその組成を一定なものに保つために、槽から一旦排出した液を槽に戻すという循環がなされているが、湿式紡糸法では一般的に、槽に供給される凝固浴液の流入方向が、紡糸原液が吐出される方向と同一方向である。しかしながら、乾湿式紡糸法で紡糸原液が吐出される方向（下向き）と水平方向に凝固浴液を流入させれば、糸条が乱れ、単繊維切れや絡まりを誘発が発生する。そのため、乾湿式紡糸法では、一般的に凝固浴液は図１に示すように循環ポンプ８を用い凝固浴底部にある凝固浴液流入口６から供給されるため、凝固浴液の流入方向は対向（上向き）となっている。循環のために凝固浴下方向から供給される凝固浴液の流れと、下向きに進行する吐出糸条の周りに随伴する液の流れ、いわゆる随伴流とが、浴内で衝突することで生じる液の乱れや、凝固浴出側の槽壁に衝突して転換した浴液の流れを糸条が受けるため、糸条の単繊維切れや絡まりを誘発し、糸条走行速度を高める上での障壁となっていた（特許文献４参照）。 However, these techniques have a great effect in the wet spinning method. However, in the dry and wet spinning method, the solidification can be achieved simply by placing a partition plate or a current plate between the spun yarn and the bottom of the coagulation bath. Until now, it has been impossible to sufficiently suppress the disturbance of the bath liquid. The reason for this is that in order to keep the composition of the coagulation bath constant, the liquid once drained from the tank is circulated back to the tank. In the wet spinning method, the coagulation bath is generally supplied to the tank. The inflow direction of the bath liquid is the same as the direction in which the spinning dope is discharged. However, if the coagulation bath liquid is allowed to flow in the direction in which the spinning dope is discharged (downward) and in the horizontal direction by the dry and wet spinning method, the yarn is disturbed, and single fiber breakage and entanglement are induced. Therefore, in the dry-wet spinning method, the coagulation bath liquid is generally supplied from the coagulation bath liquid inlet 6 at the bottom of the coagulation bath using the circulation pump 8 as shown in FIG. Opposite (upward). Liquid generated by collision of the coagulation bath liquid supplied from below the coagulation bath for circulation and the flow of liquid accompanying the discharge yarn traveling downward, the so-called accompanying flow, in the bath Since the yarn receives the turbulence of the yarn and the flow of the bath liquid that has been changed by colliding with the tank wall on the coagulation bath exit side, it is a barrier to increasing the yarn running speed by inducing single fiber breakage or entanglement of the yarn (See Patent Document 4).

前記した問題を解決するために、口金と凝固浴中の方向転換ガイドの間に、下向きに走行する糸条と適度な距離を置いて、糸条を取り囲むように整流筒を設置する技術が提案されている（特許文献３参照）。しかしながら、かかる技術では整流筒に入る前の糸条さらに出た糸条が浴液の乱れを受けるため、前記した問題を解消するには不十分であった。また、整流筒から出た糸の随伴流を制御するため、糸の流れに沿うような仕切板の設置する技術が提案されている（特許文献４参照）。しかしながら、かかる技術では整流板を回り込んで口金近傍に供給されるため、糸条走行速度が高速化すると口金近傍に供給される流れが強くなり、口金近傍の浴液流れを乱すことで、単繊維切れや単繊維間接着などの糸欠点が発生するため、前記した問題を解消するには不十分であった。 In order to solve the above-mentioned problems, a technique is proposed in which a straightening tube is installed so as to surround the yarn with a moderate distance from the yarn running downward between the base and the direction change guide in the coagulation bath. (See Patent Document 3). However, in such a technique, the yarn before entering the flow straightening tube and the yarn that has come out are subjected to the disturbance of the bath liquid, so that the above-described problem is insufficient. Moreover, in order to control the accompanying flow of the thread | yarn which came out of the rectification | straightening cylinder, the technique which installs the partition plate along the flow of a thread | yarn is proposed (refer patent document 4). However, in such a technology, the current is supplied to the base around the current plate, so when the yarn traveling speed is increased, the flow supplied to the vicinity of the base becomes stronger, and the flow of the bath liquid near the base is disturbed. Yarn defects such as fiber breakage and adhesion between single fibers occur, which is insufficient to solve the above problems.

また、口金から下方に紡出された糸条が凝固浴の底面で反射する随伴流の影響を受けにくくするため、口金から下方に紡出される糸条の周囲の全部または一部を囲む横整流板を設置する技術が提案されている（特許文献５参照）。しかしながら、かかる技術では凝固液面揺れを抑制するには有効であっても、横整流板の下部にある方向転換ガイドでは糸条が浴液の乱れを受け、またこの方向転換ガイドは糸条の進行方向が変わる部分になるため浴液の乱れの影響が大きく、糸条走行速度の増加または口金多ホール化により随伴流および槽壁に衝突して口金位置に向かう方向（上向き）に転換した浴液の流れが強くなった際に方向転換ガイドで走行糸条を大きく乱し、単繊維切れや単繊維間接着などの糸欠点を引き起こしていた。 Also, in order to make the yarn spun downward from the base less susceptible to the accompanying flow reflected from the bottom of the coagulation bath, the lateral rectification surrounding all or part of the periphery of the yarn spun downward from the base A technique for installing a plate has been proposed (see Patent Document 5). However, even if this technique is effective in suppressing the fluctuation of the coagulation liquid level, the direction change guide at the bottom of the horizontal rectifying plate is subjected to the disturbance of the bath liquid. The bath is changed in the direction (upward) toward the base position by colliding with the accompanying flow and the tank wall by increasing the yarn running speed or making the base multi-holes because the traveling direction is changed. When the liquid flow became stronger, the running yarn was greatly disturbed by the direction change guide, causing yarn defects such as single fiber breakage and adhesion between single fibers.

また、アクリロニトリル系繊維束の生産効率を高めるために、紡糸原液を吐出する多数の紡糸孔が間隔をおいて配列されて設けられた口金の外面が気相を介して凝固液の液面に向いている乾湿式紡糸用スピニングパックにおいて、前記紡糸孔の数が６，０００以上である乾湿式紡糸用スピニングパックが提案されている（特許文献６参照）。しかしながら、口金の多ホール化により吐出糸条のフィラメント数が増加し、それに伴い下向きに進行する吐出糸条の随伴流は増加する。増加した随伴流が口金近傍の浴液流れを乱すことで、単繊維切れや単繊維間接着などの糸欠点を引き起こしていた。そのため、生産効率の向上効果は不十分であった。 In addition, in order to increase the production efficiency of the acrylonitrile fiber bundle, the outer surface of the base provided with a large number of spinning holes for discharging the spinning raw liquid is arranged at intervals to face the liquid surface of the coagulation liquid via the gas phase. In the dry-wet spinning spinning pack, a dry-wet spinning spinning pack having 6,000 or more spinning holes has been proposed (see Patent Document 6). However, the number of filaments in the discharged yarn increases due to the increase in the number of holes in the die, and the accompanying flow of the discharged yarn that progresses downward increases accordingly. The increased accompanying flow disturbs the bath liquid flow in the vicinity of the die, causing yarn defects such as single fiber breakage and single fiber bonding. Therefore, the effect of improving production efficiency was insufficient.

乾湿式紡糸法において、糸条走行速度の増加または口金多ホール化させながら、安定して高品位のアクリロニトリル系繊維束を製造する方法、および具体的に浴液の流れをどこまで抑制する必要があるか定量評価された方法は開示されていなかった。 In the dry and wet spinning method, it is necessary to stably produce a high-quality acrylonitrile fiber bundle while increasing the yarn running speed or increasing the number of holes in the die, and specifically, to what extent the flow of the bath liquid needs to be suppressed. No quantitatively evaluated method was disclosed.

また、生産効率を高める手段として、特定の分子量分布の大きなＰＡＮ系重合体溶液を用いる技術が提案されている（特許文献７参照）。しかしながら、かかる技術で得られたアクリロニトリル系繊維束は、短期的に品位および工程通過性が安定していても、連続的に生産を続けていると方向転換ガイドで走行糸条が乱れることに起因する単繊維切れや単繊維間接着が、糸欠点となり、続く延伸工程において糸切れが発生していた。 In addition, as a means for improving production efficiency, a technique using a PAN polymer solution having a specific molecular weight distribution is proposed (see Patent Document 7). However, the acrylonitrile fiber bundle obtained by such a technique is caused by the running yarn being disturbed by the direction change guide if it is continuously produced even if the quality and processability are stable in the short term. The single fiber breakage and the inter-single fiber adhesion that occurred became a yarn defect, and the yarn breakage occurred in the subsequent drawing process.

特開昭６２−３３８１４号公報JP-A-62-33814 特開平１１−２２９２２７号公報Japanese Patent Laid-Open No. 11-229227 特開平１１−３５０２４４号公報JP-A-11-350244 特開２００７−２９１５９４号公報JP 2007-291594 A 国際公開第２０１３／０４７４３７号International Publication No. 2013/047437 特開２０１１−６３９２６号公報JP 2011-63926 A 特開２０１０−２５５１５９号公報JP 2010-255159 A

本発明は乾湿式紡糸において、糸条走行速度の高速化または口金多孔化しつつ、高品位のアクリロニトリル系繊維束を安定して製造できる方法を提供することにある。 An object of the present invention is to provide a method capable of stably producing a high-quality acrylonitrile fiber bundle while increasing the yarn running speed or making the die porous in dry-wet spinning.

前記目的を達成するために、本発明のアクリロニトリル系繊維束の製造方法は、次の構成を有する。すなわち、紡糸原液を、口金から一旦空気中に押し出した後、底面に配された凝固浴液流入口から上方に凝固浴液が供給される凝固浴中に下向きに進入せしめて凝固糸条とし、口金下方の凝固浴中に配された方向転換ガイドで凝固糸条を折り返して凝固浴外に引き出すアクリロニトリル系繊維束の製造方法であって、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける、凝固浴液面から深さ４０ｍｍでの凝固浴液の流れる方向の６０％以上が口金方向であり、該凝固浴液の流速の絶対値の平均が０．８ｍ／分以上であることを特徴とするアクリロニトリル系繊維束の製造方法である。 In order to achieve the object, the method for producing an acrylonitrile fiber bundle of the present invention has the following configuration. That is, the spinning dope is once extruded into the air from the die, and then entered downward into the coagulation bath supplied with the coagulation bath liquid from the coagulation bath liquid inlet disposed on the bottom surface to form a coagulated yarn, A method for producing an acrylonitrile fiber bundle that is folded back by a direction changing guide disposed in a coagulation bath below the die and pulled out of the coagulation bath, the position being 35 mm away from the outer periphery of the die, the center of the die 60% or more of the direction of flow of the coagulation bath liquid at a depth of 40 mm from the coagulation bath liquid level at each of the positions equally divided in the circumferential direction from to the circumferential direction is the cap direction, and the absolute value of the flow rate of the coagulation bath liquid Is an acrylonitrile-based fiber bundle manufacturing method, characterized in that the average is 0.8 m / min or more.

また、本発明の炭素繊維束の製造方法は、前記アクリロニトリル系繊維束の製造方法によってアクリロニトリル系繊維束を製造した後、２００〜３００℃の酸化性雰囲気中で耐炎化処理し、次いで１０００℃以上の不活性雰囲気中で加熱する炭素繊維束の製造方法である。 Moreover, the manufacturing method of the carbon fiber bundle of this invention, after manufacturing an acrylonitrile fiber bundle by the manufacturing method of the said acrylonitrile fiber bundle, flame-proofing in 200-300 degreeC oxidizing atmosphere, and then 1000 degreeC or more It is a manufacturing method of the carbon fiber bundle heated in an inert atmosphere.

本発明によれば、乾湿式紡糸法において、糸条走行速度を高速化または口金多孔化させても、吐出糸条が凝固浴中で受ける浴液抵抗を減少させることができ、それにより単繊維切れや絡まり等の品位低下要因を減少させることができ、高品位なアクリロニトリル系炭素繊維束を短時間のうちに大量に生産できるようになる。特に、炭素繊維用アクリロニトリル系前駆体繊維束を製造するに好適である。 According to the present invention, in the dry and wet spinning method, even if the yarn traveling speed is increased or the die is made porous, the bath fluid resistance that the discharged yarn receives in the coagulation bath can be reduced, and thereby the single fiber Degradation factors such as breakage and entanglement can be reduced, and high-quality acrylonitrile-based carbon fiber bundles can be produced in large quantities in a short time. In particular, it is suitable for producing an acrylonitrile-based precursor fiber bundle for carbon fibers.

従来の乾湿式紡糸装置の実施形態の一例を概略で示す側断面図である。It is a sectional side view which shows an example of embodiment of the conventional dry-wet spinning apparatus roughly. 本発明に係る乾湿式紡糸装置の実施形態の一例を示す側断面図である。It is a sectional side view which shows an example of embodiment of the dry-wet spinning apparatus which concerns on this invention. 本発明に係る乾湿式紡糸装置の実施形態の一例を示す上面図である。It is a top view which shows an example of embodiment of the dry-wet spinning apparatus which concerns on this invention. 本発明に係る乾湿式紡糸装置の実施形態の別の一例を示す側断面図である。It is a sectional side view which shows another example of embodiment of the dry-wet spinning apparatus which concerns on this invention. 本発明に係る乾湿式紡糸装置の実施形態のさらに別の一例を示す側断面図である。It is a sectional side view which shows another example of embodiment of the dry-wet spinning apparatus which concerns on this invention. 本発明に係る乾湿式紡糸装置の実施形態のさらに別の一例を示す側断面図である。It is a sectional side view which shows another example of embodiment of the dry-wet spinning apparatus which concerns on this invention. 比較例に係る乾湿式紡糸装置を示す側断面図である。It is a sectional side view which shows the dry-wet spinning apparatus which concerns on a comparative example. 比較例に係る乾湿式紡糸装置を示す上面図である。It is a top view which shows the dry-wet spinning apparatus which concerns on a comparative example. 乾湿式紡糸装置の凝固浴液の流れの方向および流速の測定方法を示す側断面図である。It is a sectional side view which shows the measuring method of the direction and flow velocity of the coagulation bath liquid of a dry-wet spinning apparatus. 乾湿式紡糸装置の凝固浴液の流れの方向および流速の測定方法を示す上面図である。It is a top view which shows the measuring method of the direction and flow rate of the coagulation bath liquid of a dry-wet spinning apparatus.

本発明は安定して高品位なアクリロニトリル系繊維束を得るために口金から吐出されたポリマーが凝固浴内に侵入する際に口金近傍の凝固浴液流れの口金方向への流れを適正化し、凝固浴液の乱れによる糸揺れが原因となる単繊維間接着や単繊維絡まり、さらには単繊維切れを抑制することにある。 The present invention optimizes the flow of the coagulation bath liquid flow in the vicinity of the die in the direction of the die when the polymer discharged from the die enters the coagulation bath in order to obtain a stable and high-quality acrylonitrile fiber bundle. The purpose is to suppress inter-single fiber adhesion, single fiber entanglement, and further, single fiber breakage, which are caused by yarn swaying due to bath liquid disturbance.

本発明について、以下に詳細を説明する。 The present invention will be described in detail below.

本発明において、アクリロニトリル系繊維束の原料となる紡糸原液は、アクリロニトリル系重合体が溶媒に溶解されてなる。アクリロニトリル系重合体としては、アクリロニトリル（以下、ＡＮと略記する）９０質量％以上を重合してなる重合体が好ましく使用される。アクリロニトリル系重合体は、ＡＮ１００質量％を重合してなるホモポリマーであってもよく、ＡＮに他のモノマーを共重合させたコポリマーであってもよい。ＡＮに共重合させるモノマーとしては、例えば、アクリル酸、メタクリル酸、イタコン酸、およびそれらアルカリ金属塩、アンモニウム塩および低級アルキルエステル類、アクリルアミドおよびその誘導体、アリルスルホン酸、メタリルスルホン酸およびそれらの塩類またはアルキルエステル類等を採用用することができる。 In the present invention, the spinning dope used as a raw material for the acrylonitrile fiber bundle is obtained by dissolving an acrylonitrile polymer in a solvent. As the acrylonitrile polymer, a polymer obtained by polymerizing 90% by mass or more of acrylonitrile (hereinafter abbreviated as AN) is preferably used. The acrylonitrile polymer may be a homopolymer obtained by polymerizing 100% by mass of AN, or a copolymer obtained by copolymerizing AN with another monomer. Examples of the monomer copolymerized with AN include acrylic acid, methacrylic acid, itaconic acid, and alkali metal salts thereof, ammonium salts and lower alkyl esters, acrylamide and derivatives thereof, allyl sulfonic acid, methallyl sulfonic acid, and their Salts or alkyl esters can be employed.

紡糸原液に用いる溶媒としては、例えば、塩化亜鉛水溶液、ジメチルアセトアミド、ジメチルスルホキシド（以下、ＤＭＳＯと略記する）、またはジメチルホルムアミド等を用いることが可能である。紡糸原液におけるアクリロニトリル系重合体の濃度は、１０質量％以上３０質量％以下であることが好ましい。かかる濃度が低すぎると、凝固浴中へ吐出した凝固糸条の単繊維がローラーとの擦過により切断され易くなり、濃度が高すぎると、口金内の圧力が大きくなり、吐出孔がポリマーにより詰まりやすく操業性が悪化することがある。 As the solvent used for the spinning dope, for example, an aqueous zinc chloride solution, dimethylacetamide, dimethylsulfoxide (hereinafter abbreviated as DMSO), dimethylformamide, or the like can be used. The concentration of the acrylonitrile polymer in the spinning dope is preferably 10% by mass or more and 30% by mass or less. If the concentration is too low, the single fibers of the coagulated yarn discharged into the coagulation bath are likely to be cut by rubbing with the roller. If the concentration is too high, the pressure in the die increases and the discharge holes are clogged with the polymer. Easy to operate and may deteriorate.

以下、図面を用いて本発明を説明する。図２および図３は本発明の一態様を例示説明するための乾湿式紡糸装置の側断面図および上面図である。 Hereinafter, the present invention will be described with reference to the drawings. 2 and 3 are a side sectional view and a top view of a dry / wet spinning apparatus for illustrating one embodiment of the present invention.

本発明では、通常、２５〜３０℃、好ましくは２７〜２９℃に温調された紡糸原液を、口金１から一旦空気中に押し出して、凝固浴液が貯蓄された凝固浴３の中に下向きに進入せしめる。ここで、凝固浴液としては、紡糸原液に使用される溶媒と同種の溶媒と水との混合液が好ましく使用できる。紡糸原液温度が低すぎると、紡糸原液の粘度が高すぎるため、口金１からの自由吐出線速度が遅すぎて、口金１から凝固浴液面７との間で単繊維切れが発生することがある。また、紡糸原液温度が高すぎると、逆に紡糸原液の粘度が低すぎるため、口金１から凝固浴液面７との間で単繊維同士の融着による操業性低下を引き起こすことがある。 In the present invention, the spinning stock solution, which has been adjusted to a temperature of 25 to 30 ° C., preferably 27 to 29 ° C., is once extruded into the air from the die 1 and directed downward into the coagulation bath 3 where the coagulation bath solution is stored. Let's enter. Here, as the coagulation bath liquid, a mixed liquid of a solvent and water of the same type as the solvent used for the spinning dope can be preferably used. If the spinning dope temperature is too low, the viscosity of the spinning dope is too high, the free discharge linear velocity from the die 1 is too slow, and single fiber breakage may occur between the die 1 and the coagulation bath liquid surface 7. is there. On the other hand, if the temperature of the spinning dope is too high, the viscosity of the spinning dope is too low, which may cause a decrease in operability due to the fusion of single fibers between the die 1 and the coagulation bath liquid surface 7.

凝固浴３の中に進入せしめた凝固糸条２は、口金１の下方の凝固浴３中に配された方向転換ガイド４で折り返されて、凝固浴出フリーローラー５を介して凝固浴外へ引き出される。図２において、循環する凝固浴液が、方向転換ガイド４の下方に位置する凝固浴液流入口６から、上向きに供給されている。また凝固糸条２の随伴流は、方向転換ガイド４の下方で凝固浴３の底面に衝突して口金１の方向（上向き）に転換する。 The coagulated yarn 2 that has entered the coagulation bath 3 is folded back by a direction changing guide 4 disposed in the coagulation bath 3 below the base 1 and is moved out of the coagulation bath through the coagulation bath discharge free roller 5. Pulled out. In FIG. 2, the circulating coagulation bath liquid is supplied upward from a coagulation bath liquid inlet 6 located below the direction change guide 4. The accompanying flow of the coagulated yarn 2 collides with the bottom surface of the coagulation bath 3 below the direction changing guide 4 and changes in the direction of the base 1 (upward).

ここで口金１の孔数増加または紡糸速度の上昇により随伴流は増加し、口金１の直下での凝固浴液の流れは随伴流により複雑な乱流になる。本発明は、この随伴流乱れを整流化することを目的とするものである。ただし、循環する凝固浴液は、凝固浴３内の温度・濃度を既定値に制御するため、循環する凝固浴液の流量は口金１の孔数増加または紡糸速度の上昇に伴い必要量だけ循環する形態とするのが好ましい。 Here, the accompanying flow increases as the number of holes in the die 1 increases or the spinning speed increases, and the flow of the coagulation bath liquid immediately below the die 1 becomes a complicated turbulent flow due to the accompanying flow. An object of the present invention is to rectify the accompanying turbulence. However, since the circulating coagulation bath liquid controls the temperature and concentration in the coagulation bath 3 to predetermined values, the circulation rate of the coagulating bath liquid circulates only by the required amount as the number of holes in the die 1 increases or the spinning speed increases. It is preferable to adopt a form.

本発明では、口金１の直下での凝固浴液の流れを整流化し、それにより単繊維切れや絡まり等の品位低下要因を減少させる点から、口金１の外周部から３５ｍｍ離れた位置であって、口金１の中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の６０％以上が口金１の方向であることが必須条件であり、好ましくは８０％以上、更に好ましくは９０％以上である。凝固浴液の流れのうち、口金１に向いているものが６０％未満である場合、口金１の直下での凝固浴液の流れが乱流化し単繊維間接着や単繊維絡まり、さらには単繊維切れ等の糸欠点が発生する。また、本発明に用いる口金孔配置に制限はなく、円形や多角形、半円形状など口金孔外周部の一部に辺を有する形状、環状の口金でも良い。 In the present invention, the flow of the coagulation bath liquid just below the base 1 is rectified, thereby reducing quality deterioration factors such as single fiber breakage and entanglement, so that the position is 35 mm away from the outer periphery of the base 1. 60% or more of the flowing direction of the coagulation bath liquid at a depth of 40 mm from the coagulation bath liquid surface 7 at each of the positions equally divided at least 10 in the circumferential direction from the center of the base 1 is the direction of the base 1. It is an essential condition, preferably 80% or more, more preferably 90% or more. If less than 60% of the flow of coagulation bath liquid is directed to the base 1, the flow of the coagulation bath liquid just below the base 1 becomes turbulent, causing bonding between single fibers or entanglement of single fibers, Yarn defects such as fiber breakage occur. Moreover, there is no restriction | limiting in the nozzle hole arrangement | positioning used for this invention, The shape which has a side in a part of nozzle hole outer peripheral parts, such as circular, a polygon, and a semicircle shape, and a cyclic | annular nozzle | cap | die.

また、生産効率の低下を抑制する点から、口金１の外周部から３５ｍｍ離れた位置であって、口金１の中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける、凝固浴液面から深さ４０ｍｍでの凝固浴液の流速の絶対値の平均は０．８ｍ／分以上であることが必須条件であり、好ましくは１．０ｍ／分以上である。 Moreover, from the point which suppresses the fall of production efficiency, it is a position 35 mm away from the outer peripheral part of the nozzle | cap | die 1, Comprising: From the coagulation bath liquid surface in each position divided | segmented at least 10 from the center of the nozzle | cap | die 1 in the circumferential direction The average absolute value of the flow rate of the coagulation bath liquid at a depth of 40 mm is an essential condition of 0.8 m / min or more, preferably 1.0 m / min or more.

ここで、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける、凝固浴液面から深さ４０ｍｍでの凝固浴液の流れる方向およびその流速の絶対値の平均は次のように求められる。 Here, the direction of the flow of the coagulation bath liquid at a depth of 40 mm from the coagulation bath liquid surface at each of the positions 35 mm away from the outer periphery of the base and equally divided into at least 10 in the circumferential direction from the center of the base The average absolute value of the flow velocity is obtained as follows.

図９および図１０に示すように、凝固浴液と比重の等しいビーズ１０を、凝固浴液面７から深さ４０ｍｍにおいて、口金中心から円周方向に均等に少なくとも１０分割、より詳細に流れ方向の分布を把握するために好ましくは２０分割以上の半径方向における直線上の口金外周部から３５ｍｍ離れた位置に一つずつ配置し、そのビーズ１０の動きを空気中から液面方向にレンズを向けてビーズ１０の動きを観察する。 As shown in FIGS. 9 and 10, beads 10 having a specific gravity equal to that of the coagulation bath liquid are divided into at least 10 parts from the center of the die evenly in the circumferential direction at a depth of 40 mm from the coagulation bath liquid surface 7, more specifically in the flow direction. In order to ascertain the distribution of the bead, it is preferably arranged one by one at a position 35 mm away from the outer periphery of the die on a straight line in a radial direction of 20 divisions or more, and the movement of the beads 10 is directed from the air in the liquid surface direction. Then, observe the movement of the beads 10.

ビーズの移動距離は、メジャー等をカメラで同時に撮影し、画像を解析することで算出する。凝固糸条の走行状態をビーズ１０の有無で違いが出ないようにするために、ビーズの外径は２ｍｍの球体状のものを用いる。 The moving distance of the beads is calculated by simultaneously photographing a measure or the like with a camera and analyzing the image. In order to prevent the running state of the coagulated yarn from being different depending on whether or not the beads 10 are present, the beads have an outer diameter of 2 mm.

各測定点において、ビーズを配置する直前と配置０．５秒後に撮影を３回行い、配置する直前と配置０．５秒後の画像を重ね合わせ、３回測定の平均においてビーズの移動前後の位置を結ぶ直線上に口金外周部があれば口金に向いていると判断する。また、移動前後のビーズの位置を結んだ距離を移動距離とし、３回測定分の平均値をＤｍｍとする。移動距離の平均値Ｄから、Ｖ＝Ｄ／８．３３の式にて凝固浴液の流速Ｖｍ／分を算出する。また、各測定点の凝固浴液の流速Ｖから流速Ｖの絶対値の平均を算出し、凝固浴液の流速の絶対値の平均とする。 At each measurement point, images were taken three times immediately before placing the beads and 0.5 seconds after placing, and the images immediately before placing and 0.5 seconds after placing were superimposed, before and after the movement of the beads in the average of three measurements. If there is an outer periphery of the base on the straight line connecting the positions, it is determined that the head is facing the base. Moreover, the distance which connected the position of the bead before and behind a movement is made into a movement distance, and let the average value for 3 times measurement be Dmm. From the average value D of the moving distance, the flow rate Vm / min of the coagulation bath liquid is calculated by the formula V = D / 8.33. Moreover, the average of the absolute value of the flow velocity V is calculated from the flow velocity V of the coagulation bath liquid at each measurement point, and is defined as the average of the absolute values of the flow velocity of the coagulation bath liquid.

口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける凝固浴液面から深さ４０ｍｍでの凝固浴液の流れる方向の６０％以上が口金方向であるようにし、該凝固浴液の流速の絶対値の平均を０．８ｍ／分以上とする手段として特に制限はされないが、例えば図２に示すように、強制送液ポンプ９を用いて凝固糸条出側より凝固液を吸い上げ、口金１の直下の凝固浴３中に、口金１の周囲から凝固糸条が方向転換ガイド４の方向へ下向きに走行する方向と直交するように凝固液を送液することで、口金１の直下での随伴流を強制的に整流化する手段、または、強制送液ポンプ９同様に口金１の直下の凝固浴３中に、電動耐溶媒性のあるプロペラを設置し口金１の周囲から凝固糸条が方向転換ガイド４の方向へ下向きに走行する方向と直交するように凝固液を送液することで、口金１の直下での随伴流を強制的に整流化する手段が挙げられる。強制送液ポンプ９はバルブ開度により流量調整が容易であり、簡便に実施ができる。口金孔数増加と紡糸速度増加に応じて強制送液ポンプ９からの送液量を増やすことで、口金１直下での凝固浴液の流れを制御できる。 More than 60% of the direction of the coagulation bath liquid flowing at a depth of 40 mm from the coagulation bath liquid level at each position at a distance of 35 mm from the outer periphery of the base and equally divided in the circumferential direction from the center of the base by at least 10% Is not particularly limited as a means for setting the average of the absolute values of the flow rate of the coagulation bath liquid to 0.8 m / min or more. For example, as shown in FIG. The coagulating liquid is sucked up from the coagulating yarn outlet side and is coagulated in the coagulating bath 3 immediately below the base 1 so that the coagulated thread runs downward from the periphery of the base 1 toward the direction change guide 4. Means for forcibly rectifying the accompanying flow directly under the base 1 or in the coagulation bath 3 directly under the base 1 as in the case of the forced liquid pump 9, which has electric solvent resistance. Install a propeller and solidify around the base 1 Article By is feeding a coagulation liquid so as to be perpendicular to the direction of travel downward in the direction of the diverting guide 4, include means for forcibly rectified the accompanying flow just below the die 1. The forced liquid feed pump 9 can easily adjust the flow rate according to the valve opening, and can be easily implemented. By increasing the amount of liquid fed from the forced liquid feeding pump 9 in accordance with the increase in the number of nozzle holes and the increase in spinning speed, the flow of the coagulation bath liquid directly under the nozzle 1 can be controlled.

なお、口金の孔数を多くすると、凝固浴内での凝固糸条の糸密度が増加し、単繊維間接着や単繊維間絡まりなど糸欠点が発生しやすくなるため、本発明のアクリロニトリル系繊維束の製造方法では、口金の孔数６０，０００以下が好ましく、さらには２４，０００以下が好ましい。また生産効率の低下を抑制する点から、孔数１，０００以上にすることが好ましく、より好ましくは３，０００以上であり、更に好ましくは６，０００以上である。 If the number of holes in the die is increased, the yarn density of the coagulated yarn in the coagulation bath is increased, and yarn defects such as inter-single fiber adhesion and inter-single fiber entanglement tend to occur. Therefore, the acrylonitrile fiber of the present invention In the bundle manufacturing method, the number of holes in the die is preferably 60,000 or less, and more preferably 24,000 or less. Moreover, from the point which suppresses the fall of production efficiency, it is preferable to set it as 1,000 or more holes, More preferably, it is 3,000 or more, More preferably, it is 6,000 or more.

凝固糸条２による凝固浴液の乱れを抑制する点および循環浴液による凝固浴液の乱れを抑制する点から、図５のように、整流筒１２および仕切板１１を有することが好ましい。整流筒１２は、口金１と方向転換ガイド４の間の凝固糸条２の周囲に備えられ、使用する口金１の形に合わせて、円形・矩形・多角形等に加工することにより糸条走行速度を向上することが可能となる。かかる整流筒１２は、その上端の位置が凝固浴液面７から下方に０〜３００ｍｍにすることが好ましく、５０〜１５０ｍｍにすることが更に好ましい。整流筒１２が、凝固浴液面７より上方に突出していると、凝固浴液の循環を阻害し、濃度斑が発生する懸念がある。また、仕切板１１は、凝固糸条２の走行位置から凝固浴３の側面および底面の方向へ、凝固糸条２の走行方向に沿うように設けることができ、仕切板１１の始端部および終端部が凝固浴液面７から深さ０〜３００ｍｍに位置するようにすることが好ましい。また、凝固浴液の乱れを可能な限り凝固糸条２に与えないために、凝固糸条２と仕切板１１の距離を２０〜２００ｍｍにすることが好ましく、５０〜１００ｍｍにすることが更に好ましい。また、５０〜１００ｍｍの距離で隔てて、凝固糸条２を取り囲むように、あるいは、凝固糸条２を挟むように仕切板１１を設置することが更に好ましい。 From the viewpoint of suppressing disturbance of the coagulation bath liquid due to the coagulated yarn 2 and suppressing disturbance of the coagulation bath liquid due to the circulating bath liquid, it is preferable to have the rectifying cylinder 12 and the partition plate 11 as shown in FIG. The flow straightening cylinder 12 is provided around the solidified yarn 2 between the base 1 and the direction changing guide 4 and is processed into a circular shape, a rectangular shape, a polygonal shape or the like according to the shape of the base 1 to be used. The speed can be improved. The rectifying cylinder 12 has an upper end position of preferably 0 to 300 mm downward from the coagulation bath liquid surface 7, and more preferably 50 to 150 mm. If the rectifying cylinder 12 protrudes above the coagulation bath liquid surface 7, there is a concern that the circulation of the coagulation bath liquid is hindered and density spots are generated. Further, the partition plate 11 can be provided along the traveling direction of the solidified yarn 2 from the traveling position of the solidified yarn 2 toward the side surface and the bottom surface of the coagulation bath 3. It is preferable that the portion is located at a depth of 0 to 300 mm from the coagulation bath liquid level 7. Moreover, in order not to give the disturbance of the coagulation bath liquid to the coagulated yarn 2 as much as possible, the distance between the coagulated yarn 2 and the partition plate 11 is preferably 20 to 200 mm, and more preferably 50 to 100 mm. . Further, it is more preferable to install the partition plate 11 so as to surround the coagulated yarn 2 at a distance of 50 to 100 mm or to sandwich the coagulated yarn 2.

乾湿式紡糸法によって紡糸し、凝固糸条を凝固浴外に引き出した後、浴中延伸を行う。この浴中延伸は、通常５０〜９８℃の延伸浴中で約２〜６倍に延伸される。なお、紡糸した凝固糸条は、好ましくは浴中延伸後水洗するか、水洗後浴中延伸することによって、残存溶媒を除去しておく。浴中延伸後は、通常、油剤を付与し、ホットローラーなどで乾燥緻密化する。また、必要があればその後、スチーム延伸等の２次延伸を行う。本発明では、これらの工程を経て得られた複数のアクリロニトリル系繊維束を巻き取るかキャンなどに収納する前に集束用フリーローラーガイド群により合糸し、巻き取り機によりパッケージに巻き取られるかキャンに収納される。また別の態様として、巻き取ったアクリロニトリル系繊維束を複数本解舒するか、キャンから引き出して集束用フリーローラーガイド群により合糸を行うこともできる。かかるアクリロニトリル系繊維束を構成する単糸数は、１，０００を超えるとき、より好ましくは２，０００を超えるときに本発明のアクリロニトリル系繊維束の製造方法の効果を好適に得ることができる。また、単糸数の上限は特に制限がないが、通常１００，０００以下である。 The fiber is spun by a dry and wet spinning method, and the coagulated yarn is drawn out of the coagulation bath and then stretched in the bath. This stretching in the bath is usually stretched about 2 to 6 times in a stretching bath at 50 to 98 ° C. The spun coagulated yarn is preferably washed with water after stretching in a bath or drawn in a bath after washing with water to remove the residual solvent. After stretching in the bath, an oil agent is usually applied and dried and densified with a hot roller or the like. If necessary, secondary stretching such as steam stretching is performed thereafter. In the present invention, whether a plurality of acrylonitrile fiber bundles obtained through these steps are wound or combined with a free roller guide group for bundling before being stored in a can and wound on a package by a winder Stored in a can. As another aspect, a plurality of wound acrylonitrile fiber bundles can be unwound or pulled out from the can and combined with a free roller guide group for focusing. When the number of single yarns constituting the acrylonitrile fiber bundle exceeds 1,000, and more preferably exceeds 2,000, the effect of the method for producing an acrylonitrile fiber bundle of the present invention can be suitably obtained. The upper limit of the number of single yarns is not particularly limited, but is usually 100,000 or less.

次に、本発明のアクリロニトリル系繊維束の製造方法によって得られたアクリロニトリル系繊維束から炭素繊維束を製造する方法について説明する。 Next, a method for producing a carbon fiber bundle from an acrylonitrile fiber bundle obtained by the method for producing an acrylonitrile fiber bundle of the present invention will be described.

前記したアクリロニトリル系繊維束の製造方法により製造されたアクリロニトリル系繊維束を、２００〜３００℃の空気などの酸化性雰囲気中において耐炎化処理する。処理温度は低温から高温に向けて複数段階に昇温するのが耐炎化繊維束を得る上で好ましく、さらに毛羽の発生を伴わない範囲で高い延伸比で繊維束を延伸するのが炭素繊維の性能を十分に発現させる上で好ましい。次いで得られた耐炎化繊維束を窒素などの不活性雰囲気中で１０００℃以上に加熱することにより、炭素繊維を製造する。その後、電解質水溶液中で陽極酸化をおこなうことにより、炭素繊維表面に官能基を付与し樹脂との接着性を高めることが可能となる。また、エポキシ樹脂等のサイジング剤を付与し、耐擦過性に優れた炭素繊維を得ることが好ましい。 The acrylonitrile fiber bundle produced by the method for producing an acrylonitrile fiber bundle is subjected to a flameproofing treatment in an oxidizing atmosphere such as air at 200 to 300 ° C. It is preferable to increase the treatment temperature in a plurality of stages from low temperature to high temperature in order to obtain a flame-resistant fiber bundle, and it is more suitable for carbon fiber to stretch the fiber bundle at a high stretch ratio without causing fluff generation. It is preferable for sufficiently expressing the performance. Subsequently, the obtained flame-resistant fiber bundle is heated to 1000 ° C. or higher in an inert atmosphere such as nitrogen to produce carbon fibers. Thereafter, by performing anodization in an aqueous electrolyte solution, it is possible to impart a functional group to the surface of the carbon fiber and enhance the adhesion to the resin. Moreover, it is preferable to provide a sizing agent such as an epoxy resin to obtain carbon fibers having excellent scratch resistance.

次に、実施例に基づき本発明を具体的に説明する。 Next, based on an Example, this invention is demonstrated concretely.

（接着評価）
凝固浴から引取後の繊維束を５０ｃｍ採取し、底が黒色で、２ｃｍ深さの水が入ったバットで繊維束を泳がせ、ばらけ具合を観察して、接着状態を評価した。評価基準は以下の通りである。
１：単繊維状にばらけている。
２：ピンセットで水中の繊維束を軽くたたくと単繊維にばらける。
３：数本単位でばらけない繊維束を含む。
４：数十本単位でばらけない繊維束を１つ含む。
５：数十本単位でばらけない繊維束を複数含む。 (Adhesion evaluation)
The fiber bundle after taking out from the coagulation bath was sampled 50 cm, the fiber bundle was swimmed with a vat with black bottom and 2 cm depth of water, and the degree of adhesion was observed to evaluate the adhesion state. The evaluation criteria are as follows.
1: Dispersed into a single fiber.
2: When tapping the fiber bundle in water with tweezers, it breaks into single fibers.
3: Including a fiber bundle that does not disperse in units of several.
4: Contains one fiber bundle that does not disperse in units of several tens.
5: Contains a plurality of fiber bundles that cannot be separated in units of several tens.

（アクリロニトリル系繊維束の品位）
アクリロニトリル系繊維束を巻き取る手前で１０００ｍ分のアクリロニトリル系繊維の毛羽の数を数え、品位を評価した。評価基準は以下の通りである。
１：（毛羽本数／１繊維束・１０００ｍ）≦１
２：１＜（毛羽本数／１繊維束・１０００ｍ）≦２
３：２＜（毛羽本数／１繊維束・１０００ｍ）≦５
４：５＜（毛羽本数／１繊維束・１０００ｍ）＜６０
５：（毛羽本数／１繊維束・１０００ｍ）≧６０
（比較例１）
図１，８に示す乾湿式紡糸装置を用いるとともに、紡糸原液として、ＡＮ９９モル％、イタコン酸１モル％を共重合してなるＡＮ共重合体を２０質量％含むＤＭＳＯ溶液を紡糸原液として用い、一錘当たりの孔数が６，０００ホールの口金から、２８℃に温調した紡糸原液を、一旦空気中に押し出して、３０質量％ＤＭＳＯ水溶液で調整された凝固浴中へ下方向に進入させ、方向転換ガイド４で角度６５°で折り返して、凝固浴外に２５ｍ／分で引き出した後、水洗工程へ搬入した。その後、浴延伸工程で延伸させながらアミノシリコーンを主成分とする油剤を付与し、更に乾燥・後延伸工程を経てアクリロニトリル系繊維束を得た。 (Quality of acrylonitrile fiber bundle)
Before winding up the acrylonitrile fiber bundle, the number of fluff of acrylonitrile fiber for 1000 m was counted, and the quality was evaluated. The evaluation criteria are as follows.
1: (number of fuzz / one fiber bundle / 1000 m) ≦ 1
2: 1 <(number of fuzz / 1 fiber bundle / 1000 m) ≦ 2
3: 2 <(number of fuzz / 1 fiber bundle · 1000 m) ≦ 5
4: 5 <(number of fuzz / 1 fiber bundle / 1000 m) <60
5: (number of fuzz / 1 fiber bundle / 1000 m) ≧ 60
(Comparative Example 1)
While using the dry and wet spinning apparatus shown in FIGS. 1 and 8, as the spinning dope, a DMSO solution containing 20% by mass of AN copolymer obtained by copolymerizing AN 99 mol% and itaconic acid 1 mol% is used as the spinning dope. The spinning dope, temperature-controlled at 28 ° C., was once extruded into air from a die having a number of holes of 6,000 holes per spindle and allowed to enter downward into a coagulation bath adjusted with a 30% by mass DMSO aqueous solution. After turning back at an angle of 65 ° with the direction change guide 4 and drawing out at 25 m / min out of the coagulation bath, it was carried into the water washing step. Then, the oil agent which has amino silicone as a main component was provided, making it extend | stretch in a bath extending process, and also the acrylonitrile-type fiber bundle was obtained through the drying and post-drawing process.

この時、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の５７％であった。接着およびアクリロニトリル系繊維製造時の品位は満足できるものではなかった。 At this time, it is 57 mm in the direction in which the coagulation bath liquid flows at a depth of 40 mm from the coagulation bath liquid surface 7 at a position that is 35 mm away from the outer periphery of the base and is equally divided into 14 in the circumferential direction from the center of the base. %Met. The quality at the time of adhesion and acrylonitrile fiber production was not satisfactory.

（実施例１）
図３，６に示す乾湿式紡糸装置を用いるとともに、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の９３％が口金方向に向くように、口金外周部から５０ｍｍ離れた位置において凝固浴液面７から深さ４０ｍｍの位置から口金方向へ凝固浴液を送液できるよう２つの強制送液ポンプ９を設置し送液量を調整した以外は比較例１と同様にしてアクリロニトリル系繊維束を得た。接着およびアクリロニトリル系繊維製造時の品位は良好であった。 Example 1
3 and 6, the depth from the coagulation bath liquid surface 7 at a position 35 mm away from the outer periphery of the die and 14 equally divided from the center of the die in the circumferential direction. The coagulation bath liquid is fed from the position of the coagulation bath liquid surface 7 to a depth of 40 mm from the position of the coagulation bath liquid surface 7 at a position 50 mm away from the outer periphery of the base so that 93% of the direction of flow of the coagulation bath liquid at 40 mm is directed toward the base. An acrylonitrile fiber bundle was obtained in the same manner as in Comparative Example 1 except that two forced liquid feeding pumps 9 were installed to adjust the liquid feeding amount. The quality during bonding and acrylonitrile fiber production was good.

（実施例２）
図７，８に示す乾湿式紡糸装置を用いる以外は比較例１と同様にしてアクリロニトリル系繊維束を得た。この時、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の８６％であった。接着およびアクリロニトリル系繊維製造時の品位は実施例１と同等であり満足できるものであった。 (Example 2)
An acrylonitrile fiber bundle was obtained in the same manner as in Comparative Example 1 except that the dry and wet spinning apparatus shown in FIGS. At this time, 86 in the direction in which the coagulation bath liquid flows at a depth of 40 mm from the coagulation bath liquid surface 7 at a position that is 35 mm away from the outer periphery of the base and is equally divided into 14 in the circumferential direction from the center of the base. %Met. The quality at the time of adhesion and acrylonitrile fiber production was the same as in Example 1 and was satisfactory.

（比較例２）
図１，８に示す乾湿式紡糸装置を用い、凝固浴外に３５ｍ／分で引き出した以外は比較例１と同様にしてアクリロニトリル系繊維束を得た。この時、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の２９％であった。接着およびアクリロニトリル系繊維製造時の品位は比較例１と比べ悪化し、満足できるものではなかった。 (Comparative Example 2)
An acrylonitrile fiber bundle was obtained in the same manner as in Comparative Example 1 except that the wet and wet spinning apparatus shown in FIGS. 1 and 8 was used and drawn out at 35 m / min out of the coagulation bath. At this time, it is 29 mm in the direction in which the coagulating bath liquid flows at a depth of 40 mm from the coagulating bath liquid level 7 at each of the positions 35 mm away from the outer periphery of the base and equally divided into 14 circumferentially from the center of the base %Met. The quality at the time of adhesion and acrylonitrile fiber production was worse than that of Comparative Example 1 and was not satisfactory.

（実施例３）
図３，６に示す乾湿式紡糸装置を用い、凝固浴外に３５ｍ／分で引き出すとともに、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の６４％が口金方向に向くよう強制送液ポンプ９の送液量を調整した以外は実施例１と同様にしてアクリロニトリル系繊維束を得た。接着およびアクリロニトリル系繊維製造時の品位は問題なかった。また、凝固浴外に引き出す速度が実施例２の２５ｍ／分から３５ｍ／分に高速化していることに比例して、その生産効率は向上し、その製造原価は満足できるものであった。 (Example 3)
Using the dry and wet spinning apparatus shown in FIGS. 3 and 6, the position is drawn out at 35 m / min to the outside of the coagulation bath, and the position is 35 mm away from the outer periphery of the base and is equally divided into 14 in the circumferential direction from the center of the base. In the same manner as in Example 1, except that the liquid feed amount of the forced liquid feed pump 9 was adjusted so that 64% of the flow direction of the coagulation bath liquid at a depth of 40 mm from the coagulation bath liquid surface 7 was directed toward the die. A fiber bundle was obtained. There was no problem in the quality of adhesion and acrylonitrile fiber production. In addition, the production efficiency was improved in proportion to the speed of drawing out of the coagulation bath from 25 m / min in Example 2 to 35 m / min, and the manufacturing cost was satisfactory.

（比較例３）
図７，８に示す乾湿式紡糸装置を用いる以外は比較例２と同様にしてアクリロニトリル系繊維束を得た。この時、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の５０％であった。接着およびアクリロニトリル系繊維製造時の品位は比較例２に比べ改善は見られたが、依然満足できるものではなかった。 (Comparative Example 3)
An acrylonitrile fiber bundle was obtained in the same manner as in Comparative Example 2 except that the dry and wet spinning apparatus shown in FIGS. At this time, 50 in the direction in which the coagulating bath liquid flows at a depth of 40 mm from the coagulating bath liquid surface 7 at positions that are 35 mm away from the outer periphery of the base and equally divided into 14 in the circumferential direction from the center of the base. %Met. Although the quality at the time of adhesion and acrylonitrile fiber production was improved as compared with Comparative Example 2, it was still not satisfactory.

（実施例４）
図２，３に示す乾湿式紡糸装置を用いるとともに、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の７９％が口金方向に向くよう強制送液ポンプ９の送液量を調整した以外は実施例３と同様にしてアクリロニトリル系繊維束を得た。接着は問題なく、アクリロニトリル系繊維製造時の品位は実施例２に比べ改善した。また、凝固浴外に引き出す速度が実施例１の２５ｍ／分から３５ｍ／分に高速化していることに比例して、その生産効率は向上し、その製造原価は満足できるものであった。 Example 4
While using the dry and wet spinning apparatus shown in FIGS. 2 and 3, the depth from the coagulating bath liquid surface 7 at a position 35 mm away from the outer periphery of the die and equally divided into 14 in the circumferential direction from the center of the die. An acrylonitrile fiber bundle was obtained in the same manner as in Example 3 except that the liquid feed amount of the forced liquid feed pump 9 was adjusted so that 79% of the coagulating bath liquid flow direction at 40 mm was directed toward the die. There was no problem in adhesion, and the quality when producing acrylonitrile fiber was improved as compared with Example 2. In addition, the production efficiency was improved in proportion to the speed of drawing out of the coagulation bath from 25 m / min in Example 1 to 35 m / min, and the manufacturing cost was satisfactory.

（実施例５）
図３、４に示す乾湿式紡糸装置を用いるとともに、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の７１％が口金方向に向くよう強制送液ポンプ９の送液量を調整した以外は実施例３と同様にしてアクリロニトリル系繊維束を得た。接着は実施例２に比べ改善し、アクリロニトリル系繊維製造時の品位は問題なかった。また、凝固浴外に引き出す速度が実施例１の２５ｍ／分から３５ｍ／分に高速化していることに比例して、その生産効率は向上し、その製造原価は満足できるものであった。 (Example 5)
3 and 4, the depth from the coagulation bath liquid surface 7 at a position 35 mm away from the outer periphery of the die and 14 equally divided from the center of the die in the circumferential direction. An acrylonitrile fiber bundle was obtained in the same manner as in Example 3 except that the liquid feed amount of the forced liquid feed pump 9 was adjusted so that 71% of the coagulating bath liquid flow direction at 40 mm was directed toward the die. Adhesion was improved as compared with Example 2, and there was no problem in the quality when acrylonitrile fiber was produced. In addition, the production efficiency was improved in proportion to the speed of drawing out of the coagulation bath from 25 m / min in Example 1 to 35 m / min, and the manufacturing cost was satisfactory.

（実施例６）
図３、５に示す乾湿式紡糸装置を用いるとともに、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に１４分割した位置それぞれにおける、凝固浴液面７から深さ４０ｍｍでの凝固浴液の流れる方向の８６％が口金方向に向くよう強制送液ポンプ９の送液量を調整した以外は実施例３と同様にしてアクリロニトリル系繊維束を得た。接着およびアクリロニトリル系繊維製造時の品位は実施例２に比べ改善し良好であった。また、凝固浴外に引き出す速度が実施例１の２５ｍ／分から３５ｍ／分に高速化していることに比例して、その生産効率は向上し、その製造原価は満足できるものであった。 (Example 6)
3 and 5, the depth from the coagulation bath liquid surface 7 at a position 35 mm away from the outer periphery of the die and 14 equally divided from the center of the die in the circumferential direction. An acrylonitrile fiber bundle was obtained in the same manner as in Example 3 except that the liquid feed amount of the forced liquid feed pump 9 was adjusted so that 86% of the coagulating bath liquid flow direction at 40 mm was directed toward the die. The quality at the time of adhesion and acrylonitrile fiber production was improved compared with Example 2 and was good. In addition, the production efficiency was improved in proportion to the speed of drawing out of the coagulation bath from 25 m / min in Example 1 to 35 m / min, and the manufacturing cost was satisfactory.

１口金
２凝固糸条
３凝固浴
４方向転換ガイド
５凝固浴出フリーローラー
６凝固浴液流入口
７凝固浴液面
８循環ポンプ
９強制送液ポンプ
１０ビーズ
１１仕切板
１２整流筒
1 Coupling 2 Coagulated yarn 3 Coagulation bath 4 Direction change guide 5 Coagulation bath discharge free roller 6 Coagulation bath liquid inlet 7 Coagulation bath liquid level 8 Circulating pump 9 Forced liquid feeding pump 10 Beads 11 Partition plate 12 Rectifier cylinder

Claims

紡糸原液を、口金から一旦空気中に押し出した後、底面に配された凝固浴液流入口から上方に凝固浴液が供給される凝固浴中に下向きに進入せしめて凝固糸条とし、口金下方の凝固浴中に配された方向転換ガイドで凝固糸条を折り返して凝固浴外に引き出すアクリロニトリル系繊維束の製造方法であって、口金外周部から３５ｍｍ離れた位置であって、口金中心から円周方向に均等に少なくとも１０分割した位置それぞれにおける、凝固浴液面から深さ４０ｍｍでの凝固浴液の流れる方向の６０％以上が口金方向であり、該凝固浴液の流速の絶対値の平均が０．８ｍ／分以上であることを特徴とするアクリロニトリル系繊維束の製造方法。 The spinning solution is once extruded from the die into the air, and then entered downward into the coagulation bath supplied with the coagulation bath solution from the coagulation bath solution inlet located on the bottom to form a coagulated yarn. A acrylonitrile fiber bundle manufacturing method for folding a coagulated yarn with a direction change guide arranged in the coagulation bath and drawing it out of the coagulation bath, at a position 35 mm away from the outer periphery of the die and from the center of the die 60% or more of the direction of flow of the coagulation bath liquid at a depth of 40 mm from the coagulation bath liquid surface in each of the positions equally divided into at least 10 in the circumferential direction is the die direction, and the average of the absolute values of the flow rates of the coagulation bath liquid Is a method for producing an acrylonitrile-based fiber bundle, which is 0.8 m / min or more.

凝固糸条を凝固浴外に引き出す速度が２５〜５０ｍ／分である請求項１に記載のアクリロニトリル系繊維束の製造方法。 The method for producing an acrylonitrile fiber bundle according to claim 1, wherein a speed at which the coagulated yarn is drawn out of the coagulation bath is 25 to 50 m / min.

口金の孔数が１，０００〜６０，０００である請求項１または２に記載のアクリロニトリル系繊維束の製造方法。 The method for producing an acrylonitrile fiber bundle according to claim 1 or 2, wherein the number of holes in the die is 1,000 to 60,000.

凝固浴液が口金方向へ流れるように凝固浴液の流れを制御する手段を凝固浴内に備える請求項１〜３のいずれかに記載のアクリロニトリル系繊維束の製造方法。 The method for producing an acrylonitrile fiber bundle according to any one of claims 1 to 3, wherein means for controlling the flow of the coagulation bath liquid is provided in the coagulation bath so that the coagulation bath liquid flows in the direction of the die.

凝固糸条の走行位置から凝固浴の側面および底面の方向へ２０〜２００ｍｍ離れた位置に、凝固糸条の走行方向に沿った形状の仕切板を備え、仕切板の始端部および終端部は凝固浴液面から深さ０〜３００ｍｍに位置する請求項１〜４のいずれかに記載のアクリロニトリル系繊維束の製造方法。 A partition plate having a shape along the running direction of the coagulated yarn is provided at a position 20 to 200 mm away from the running position of the coagulated yarn in the direction of the side and bottom of the coagulation bath, and the start and end portions of the partition plate are solidified. The method for producing an acrylonitrile fiber bundle according to any one of claims 1 to 4, which is located at a depth of 0 to 300 mm from the bath liquid surface.

口金と方向転換ガイドの間の凝固糸条の周囲に整流筒を備える請求項１〜５のいずれかに記載のアクリロニトリル系繊維束の製造方法。 The method for producing an acrylonitrile fiber bundle according to any one of claims 1 to 5, further comprising a flow straightening tube around a solidified yarn between the die and the direction changing guide.

請求項１〜６のいずれかに記載のアクリロニトリル系繊維束の製造方法によってアクリロニトリル系繊維束を製造した後、２００〜３００℃の酸化性雰囲気中で耐炎化処理し、次いで１０００℃以上の不活性雰囲気中で加熱する炭素繊維束の製造方法。
An acrylonitrile fiber bundle is produced by the method for producing an acrylonitrile fiber bundle according to any one of claims 1 to 6, followed by flameproofing in an oxidizing atmosphere at 200 to 300 ° C, and then inert at 1000 ° C or more. A method for producing a carbon fiber bundle heated in an atmosphere.