JP3078158B2 - Acrylic flat fiber and method for producing the same - Google Patents

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は、アクリル系偏平繊維及
びその製造方法に関するものである。The present invention relates to an acrylic flat fiber and a method for producing the same.

【０００２】[0002]

【従来の技術】従来、アクリル系合成繊維は最も獣毛調
風合、光沢を有する繊維として認められ、天然毛皮を想
定したボアー，シール等のイミテーションファー分野及
びハイパイル分野に汎く使用されている。2. Description of the Related Art Conventionally, acrylic synthetic fibers have been recognized as fibers having the best animal hair feeling and luster, and are widely used in imitation fur fields such as bores and seals assuming natural fur and in high pile fields. .

【０００３】近年、風合・光沢をより天然の獣毛に近づ
けるため後加工や紡糸原液に各種添加剤を添加する等の
色々な改良が行われている。しかし、紡績性から考える
と加工剤を多量に添加することは好ましくなく、又効果
も洗濯及びドライクリーニングによる耐久性が無く一時
的なものである。これらの欠点を克服するためには、紡
糸原液段階での何らかの工夫が好ましい。例えば特公昭
５６−４４１６３号公報，特公昭５６−４４１６４号公
報にはアクリロニトリル（以下ＡＮと略称する）の共重
合体を有機溶剤に溶解させた紡糸原液に金属化合物とセ
ルローズ誘導体を添加する製造方法が記載されている。
これは金属化合物によるしゃへい効果とセルローズ誘導
体によるＡＮ共重合体との相分離効果の相乗作用で風
合，光沢を天然の獣毛に近ずけるというものである。後
加工に比べ、耐洗濯性，耐ドライクリーニング性に優れ
てはいるものの、光沢を天然の獣毛並にするには金属化
合物，セルローズ誘導体のうち特に金属化合物を多量に
添加しなければならない。しかし斯かる繊維は、繊維表
面に多量の金属化合物が露出しており著しく可紡性及び
紡績性の低下を惹き起こすという欠点を有している。
又、アクリル系繊維はボアー，ハイパイルの他に寝装
品，カーペット，マット，ニット用の素材としても汎く
認められており、最近ではこちらの商品でも獣毛調風合
（偏平断面）が望まれる様になってきた。しかし、特公
昭５６−４４１６３号公報，特公昭５６−４４１６４号
公報記載の繊維では耐熱性に劣り、後加工段階で様々な
問題点が出てくる。In recent years, various improvements such as post-processing and addition of various additives to a spinning dope have been made in order to make the feeling and gloss more similar to natural animal hair. However, from the standpoint of spinnability, it is not preferable to add a large amount of a processing agent, and the effect is temporary without durability due to washing and dry cleaning. To overcome these drawbacks, some contrivance at the spinning dope stage is preferred. For example, JP-B-56-44163 and JP-B-56-44164 disclose a production method in which a metal compound and a cellulose derivative are added to a spinning solution obtained by dissolving a copolymer of acrylonitrile (hereinafter abbreviated as AN) in an organic solvent. Is described.
This means that the feeling and luster can be made closer to that of natural animal hair by the synergistic action of the shielding effect of the metal compound and the phase separation effect of the cellulose derivative with the AN copolymer. Although it has better washing resistance and dry cleaning resistance than post-processing, it is necessary to add a large amount of a metal compound or a cellulosic derivative, especially a metal compound, in order to obtain a luster comparable to that of natural animal hair. However, such fibers have a disadvantage that a large amount of metal compound is exposed on the fiber surface, which causes a marked decrease in spinnability and spinnability.
In addition, acrylic fiber is widely accepted as a material for bedding, carpet, mat, and knit, as well as bore and high pile. It has become However, the fibers described in JP-B-56-44163 and JP-B-56-44164 are inferior in heat resistance and cause various problems in a post-processing stage.

【０００４】特開平２−１６９７１１号公報、特開平２
−１６９７１２号公報に、アクリロニトリルが８５重量
％以上である共重合体を用いた偏平繊維が開示されてい
るが、共に乾式紡糸に関する発明であり紡糸口金の長辺
／短辺比に比べ得られる繊維断面の長軸／短軸比は非常
に小さくなってしまう。[0004] JP-A-2-169711, JP-A-2
Japanese Patent Application Publication No. 169712 discloses flat fibers using a copolymer containing 85% by weight or more of acrylonitrile, both of which are related to dry spinning and are fibers which can be obtained in comparison with a long side / short side ratio of a spinneret. The long axis / short axis ratio of the cross section becomes very small.

【０００５】[0005]

【発明が解決しようとする課題】本発明者らはかかる現
状に鑑み、鋭意検討の結果本発明に到達した。本発明の
目的はボアー，ハイパイルのみならずカーペット，マッ
ト用途の獣毛調風合を有するアクリル系偏平繊維、及び
これを工業的容易に製造する方法を提供する事にある。SUMMARY OF THE INVENTION In view of the above situation, the present inventors have made intensive studies and arrived at the present invention. SUMMARY OF THE INVENTION An object of the present invention is to provide an acrylic flat fiber having animal hair feeling for use in carpets and mats as well as bores and high piles, and a method for industrially easily producing the same.

【０００６】[0006]

【課題を解決するための手段】すなわち、本発明のアク
リル系偏平繊維は、アクリロニトリル８４〜９４．３重
量％，スルホン酸基含有ビニル系モノマー０．７〜３．
０重量％及び他のビニル系モノマー５〜１５重量％より
なり且つ分子量が４〜５万である共重合体を湿式紡糸し
てなるアクリル系繊維であって、繊維横断面の長軸／短
軸比が４．５以上１５以下であることを特徴とする。That is, the acrylic flat fiber of the present invention comprises 84 to 94.3 % by weight of acrylonitrile and 0.7 to 3% of a vinyl monomer having a sulfonic acid group.
Acrylic fiber obtained by wet spinning a copolymer comprising 0% by weight and 5 to 15% by weight of another vinyl monomer and having a molecular weight of 40,000 to 50,000. The ratio is 4.5 or more and 15 or less.

【０００７】また本発明の製造方法は、アクリロニトリ
ルを８４〜９４．３重量％とスルホン酸基含有モノマー
０．７〜３．０重量％及び他のビニル系モノマー５〜１
５重量％よりなり且つ分子量が４〜５万である共重合体
を重合し、次いで該重合体とジメチルホルムアミド／水
＝９６／４〜９４／６（重量比）よりなる重合体濃度２
５〜３２％の紡糸原液を調製し、そして孔形状が矩形の
口金を用いてジメチルホルムアミド／水系よりなる凝固
浴中に紡糸ドラフト比０．６〜１．５で紡糸する事を特
徴とする。In the production method of the present invention, acrylonitrile is contained in an amount of 84 to 94.3 % by weight, a sulfonic acid group-containing monomer in an amount of 0.7 to 3.0% by weight, and other vinyl monomers 5-1 to 5-1.
A copolymer comprising 5% by weight and having a molecular weight of 40,000 to 50,000 is polymerized, and then a polymer concentration of 96/4 to 94/6 (weight ratio) of the polymer and dimethylformamide / water = 2
A spinning solution having a spinning draft ratio of 0.6 to 1.5 is prepared in a coagulation bath of dimethylformamide / water system using a spinneret having a rectangular shape with a pore shape of 5 to 32%.

【０００８】本発明に使用するアクリロニトリル系共重
合体はアクリロニトリルを８４〜９４．７重量％とスル
ホン酸基を含有しない他のビニル系モノマーを５〜１５
重量％共重合する。９４．７重量％を越えるとゲル化な
ど操業性が低下する。ここでアクリロニトリルが８４重
量％未満ではアクリル系繊維としての通常の物性，耐熱
性が得られない。又、スルホン酸基を含有しない他のビ
ニル系モノマーを５重量％以上共重合しないと、ゲル化
し易くなり操業性が低下する。一方１５重量％を越える
と繊維の物性，耐熱性が低下し、工業的に製造する事が
著しく困難になり、この点に関しては同業者ならば周知
の事である。ビニル系モノマーとしてはアクリル酸，メ
タクリル酸，或いはこれらのアルキルエステル類，酢酸
ビニル，塩化ビニル，塩化ビニリデンが好ましい。The acrylonitrile copolymer used in the present invention is composed of 84 to 94.7 % by weight of acrylonitrile and 5 to 15 of another vinyl monomer containing no sulfonic acid group.
% By weight. If it exceeds 94.7 % by weight, operability such as gelation will be reduced. If the acrylonitrile content is less than 84% by weight, the usual physical properties and heat resistance of the acrylic fiber cannot be obtained. Unless 5% by weight or more of another vinyl monomer containing no sulfonic acid group is copolymerized, gelation easily occurs and operability decreases. On the other hand, if it exceeds 15% by weight, the physical properties and heat resistance of the fiber deteriorate, making it extremely difficult to industrially manufacture the fiber. This point is well known to those skilled in the art. As the vinyl monomer, acrylic acid, methacrylic acid, or alkyl esters thereof, vinyl acetate, vinyl chloride, and vinylidene chloride are preferable.

【０００９】本発明に於いて特に重要なのはスルホン酸
基含有モノマー０．７〜３．０重量％（好ましくは１．
０〜２．０重量％）共重合している事と共重合体のジメ
チルホルムアミド（ＤＭＦ）／水 溶液中での濃度すな
わち紡糸原液を２５〜３２重量％に調製する点にある。
スルホン酸基含有モノマーとしてはメタリルスルホン
酸，アリルスルホン酸，２−アクリルアミド−２−メチ
ルプロパンスルホン酸及びそれらの塩がある。この中で
もメタリルスルホン酸のソーダ塩が重合初期にブロック
的に導入されるため共重合体をより親水サイドにする事
が出来、その結果、繊維断面が整い良好な光沢が得られ
るので好ましい。この技術思想については、本発明者ら
が先に提案した特公昭５３−９２９９号公報，特公昭５
３−９３００号公報、特公昭５３−２９７３４号公報に
記載の発明に基づいている。スルホン酸基含有モノマー
が０．７重量％未満では、共重合体の親水性が不足し断
面の崩れた繊維になるばかりでなく、失透し染色性も不
足する。一方３．０重量％を越えると、凝固工程で膠着
しやすくなり淡色での染色が困難になってくる。Particularly important in the present invention is 0.7 to 3.0% by weight of the sulfonic acid group-containing monomer (preferably 1.
(0 to 2.0% by weight) and that the concentration of the copolymer in a dimethylformamide (DMF) / water solution, that is, the spinning solution is adjusted to 25 to 32% by weight.
Examples of the sulfonic acid group-containing monomer include methallyl sulfonic acid, allyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and salts thereof. Of these, the soda salt of methallyl sulfonic acid is introduced in a block manner in the early stage of polymerization, so that the copolymer can be made more hydrophilic, and as a result, the fiber cross section is adjusted and good gloss is obtained, which is preferable. Regarding this technical idea, Japanese Patent Publication No. 53-9299 and Japanese Patent Publication No. Sho 5-5 previously proposed by the present inventors.
3-9300 and Japanese Patent Publication No. 53-29734. If the amount of the sulfonic acid group-containing monomer is less than 0.7% by weight, not only the copolymer becomes insufficient in hydrophilicity and becomes a fiber having a broken cross section, but also devitrified and insufficient in dyeability. On the other hand, if the content exceeds 3.0% by weight, sticking tends to occur in the coagulation step, and it becomes difficult to dye in a light color.

【００１０】共重合体の分子量（重量平均）は、４〜５
万であることが必要である。４万未満では繊維の強伸度
などの物性が劣り、一方５万を越えると紡糸原液の粘度
が高くなるため濃度を高くできず、脱溶媒量が大きくな
る分偏平形状が崩れやすくなる。The molecular weight (weight average) of the copolymer is 4-5.
It is necessary to be ten thousand. If it is less than 40,000, the physical properties such as fiber elongation are inferior. On the other hand, if it exceeds 50,000, the viscosity of the spinning dope becomes too high to increase the concentration.

【００１１】本発明に使用する共重合体の紡糸原液での
濃度は２５〜３２％に調製する。この濃度が２５％未満
では口金から吐出した際の脱溶媒量が多く、整った偏平
断面を得ることが困難となる。一方、３２％を越える
と、共重合体の分子量にもよるが、粘度が高くなり紡糸
原液がゲル化し易くなるばかりでなく、紡糸時の単糸切
れも多くなる。また紡糸原液の溶媒は、ＤＭＦ／水＝９
６／４〜９４／６（重量比）であることが必要である。
水添量が４％未満では、凝固工程でマクロボイドが多発
して失透し、形状も崩れる。一方６％を越えると、ゲル
化して紡糸が困難となる。The concentration of the copolymer used in the present invention in the stock solution for spinning is adjusted to 25 to 32%. If the concentration is less than 25%, the amount of solvent removed when discharged from the die is large, and it is difficult to obtain a well-formed flat cross section. On the other hand, if it exceeds 32%, depending on the molecular weight of the copolymer, not only the viscosity becomes high and the spinning stock solution tends to gel, but also the single yarn breakage during spinning increases. The solvent of the spinning dope was DMF / water = 9.
It is necessary that the ratio be 6/4 to 94/6 (weight ratio).
If the amount of hydrogenation is less than 4%, macrovoids frequently occur in the coagulation step, devitrify, and the shape is lost. On the other hand, if it exceeds 6%, gelation occurs and spinning becomes difficult.

【００１２】上記共重合体の重合方法は通常知られてい
るビニル系単量体の重合方法であればいずれでも良い
が、溶液重合が品質，コスト的に好ましい。The method of polymerizing the copolymer may be any known method of polymerizing a vinyl monomer, but solution polymerization is preferred in terms of quality and cost.

【００１３】本発明に使用する口金は孔形状が矩形状の
もので孔面積は繊維のデニールに合わせたものを適宜選
択する。かかる条件において、長辺／短辺比（Ａ）が
４．５以上である矩形状の口金を用いると、下記式を満
足する繊維横断面の長軸／短軸比（Ｂ）を有する偏平繊
維を湿式紡糸することにより製造することができる。 ０．８Ａ≦Ｂ≦Ａ 更に好ましい条件を選べば、下記式を満足する偏平繊維
も製造することができる。 ０．９Ａ≦Ｂ≦ＡThe die used in the present invention has a rectangular hole shape and the hole area is appropriately selected according to the denier of the fiber. Under such conditions, when a rectangular base having a long side / short side ratio (A) of 4.5 or more is used, a flat fiber having a long axis / short axis ratio (B) of a fiber cross section satisfying the following equation: Can be produced by wet spinning. 0.8A ≦ B ≦ A If more preferable conditions are selected, flat fibers satisfying the following formula can also be produced. 0.9A ≦ B ≦ A

【００１４】本発明は、紡糸ドラフト比（巻取り速度／
吐出線速度の比 以下ｉ価と表記）を０．６〜１．５で
引き取る。本発明の繊維を得る上でｉ価は重要なファク
ターである。ｉ価が０．６未満で得られた繊維は、断面
形状が丸味を帯び良好な獣毛調風合が得られなくなる。
逆に１．５を越えると凝固浴中での切れが多発し、操業
が困難になる。凝固浴より導出された凝固糸条は、水洗
又は水洗と同時に延伸、又は水洗後延伸等の処理をした
後、乾燥緻密化させ、更に機械捲縮を付与させ種々の高
次加工を施す。In the present invention, the spinning draft ratio (winding speed /
The ratio of the ejection linear velocity (hereinafter referred to as i-valency) is taken from 0.6 to 1.5. The i value is an important factor in obtaining the fiber of the present invention. The fiber obtained with an i-value of less than 0.6 has a round cross-sectional shape, and a good animal hair feeling cannot be obtained.
On the other hand, when the ratio exceeds 1.5, cuts frequently occur in the coagulation bath, and the operation becomes difficult. The coagulated yarn led out of the coagulation bath is subjected to water washing, stretching at the same time as washing with water, or stretching after washing with water, followed by drying and densification, further mechanical crimping and various high-order processing.

【００１５】本発明方法で製造されるアクリル系繊維
は、口金の形状を忠実に再現した偏平形状をしており、
その長軸／短軸比（Ｂ）は通常４．５〜１５程度必要で
ある。この比が４．５以上好ましくは６〜１５であれ
ば、織編物、糸などの繊維製品とした際良好な獣毛調風
合いが得られる。The acrylic fiber produced by the method of the present invention has a flat shape that faithfully reproduces the shape of the die.
Its long axis / short axis ratio (B) is usually required about 4.5 to 15. When this ratio is at least 4.5, and preferably from 6 to 15, a good animal hair texture can be obtained when it is used as a textile product such as a woven or knitted fabric or a yarn.

【００１６】[0016]

【実施例】以下、本発明の実施例について具体的に説明
すると共に、比較例を挙げ本発明の繊維が優れた特性を
有する事を明らかにする。EXAMPLES Examples of the present invention will be specifically described below, and comparative examples will be given to clarify that the fibers of the present invention have excellent properties.

【００１７】実施例１〜４，比較例１〜４ アクリロニトリル（ＡＮ）／メチルアクリレート（Ｍ
Ａ）／メタリルスルホン酸ソーダ（ＳＭＡＳ）＝８７．
７／１１．５／０．８のモノマー組成から成る、分子量
４万（数平均）のアクリル系共重合体のＤＭＦ／水（＝
９５．５／４．５）溶液を表１記載の濃度に調製し紡糸
原液とした。各々の原液を０．０５６×０．３３６ｍ
ｍ、２５，００２孔の矩形型口金を通して２０℃，６０
％のＤＭＦ溶液中へ表１記載のｉ価で紡出した。紡出し
た後、ＤＭＦ濃度が３０％，２０％，１５％と順次低下
する３個の浴槽にて脱溶剤と４．０倍の１次延伸を行っ
た後、６０℃の水洗槽にて十分洗浄し前オイル槽にて油
剤付着し、その後、１４０℃のホットローラーにて乾
燥，緻密化した。乾燥後は１１７℃の蒸熱にて１．３倍
の２次延伸及び１２０℃の蒸熱下で０．９倍の緊張収縮
を行い後オイル付着，クリンプ付与後，乾燥し、単糸７
ｄ繊維長１０２ｍｍのアクリル系偏平繊維を得た。Examples 1-4, Comparative Examples 1-4 Acrylonitrile (AN) / methyl acrylate (M
A) / Sodium methallylsulfonate (SMAS) = 87.
DMF / water of an acrylic copolymer having a monomer composition of 7 / 11.5 / 0.8 and having a molecular weight of 40,000 (number average)
95.5 / 4.5) The solution was adjusted to the concentration shown in Table 1 and used as a stock solution for spinning. 0.056 × 0.336m for each stock solution
m, 20 ° C, 60 through a 25,002 hole rectangular die.
% In a DMF solution at an i value shown in Table 1. After spinning, the solvent is removed in three bathtubs in which the DMF concentration gradually decreases to 30%, 20%, and 15%, and the primary stretching is performed 4.0 times. After washing, the oil agent adhered to the oil tank before drying, and then dried and densified with a hot roller at 140 ° C. After drying the deposited post-oil perform 0.9 times the tension contraction steaming under secondary stretching and 120 ° C. 1.3-fold at the 117 ° C. steaming, after crimping, dried, single yarn 7
d Obtained an acrylic flat fiber having a fiber length of 102 mm.

【００１８】この様にして得られたアクリル系合成繊維
をカードに通し開綿を得た。開綿を用いて５名の判定者
により官能検査を行い風合のそれぞれが天然獣毛に類似
した触感と光沢を有しているものを「◎」とし、やや類
似しているものを「○」、異なるものを「×」として三
段階で判定した。又、操業性の判定は実施例記載の条件
で製造した際の単糸切れ，ローラー巻き付きを総合して
「◎」，「○」，「△」，「×」の四段階で行った。The acrylic synthetic fiber thus obtained was passed through a card to obtain cotton. A sensory test was conducted by five judges using open cotton, and those with a texture and gloss similar to that of natural animal hair were marked with “◎”, and those with a slight similarity were marked with “○”. ”And a different one was evaluated as“ x ”in three stages. The operability was determined in four stages of “◎”, “○”, “△”, and “×”, taking into account the breakage of single yarn and winding with a roller when manufactured under the conditions described in the examples.

【００１９】[0019]

【表１】 [Table 1]

【００２０】実施例５〜６，比較例５〜８ 表２記載のＡＮ／ＭＡ／ＳＭＡＳ組成比率から成る、分
子量４．５万のアクリル系共重合体を２８％のＤＭＦ／
水（＝９５．５／４．５）溶液に調製し紡糸原液とし
た。各々の原液を０．０５６×０．３３６ｍ／ｍ，１０
００孔の矩形型口金を通してｉ価１．０で２０℃，５８
％のＤＭＦ溶液中へ紡出した。紡出後、脱溶剤と延伸を
施し十分洗浄して油剤付与，乾燥，クリンプ付与して最
終的に１０ｄのアクリル系偏平繊維を得た。得られたア
クリル系偏平繊維をカードに通し開綿し風合と偏平比を
評価した。Examples 5 to 6 and Comparative Examples 5 to 8 An acrylic copolymer having a molecular weight of 45,000 and having an AN / MA / SMAS composition ratio shown in Table 2 was converted to 28% DMF /
It was prepared in a water (= 95.5 / 4.5) solution to prepare a spinning stock solution. Each undiluted solution was 0.056 × 0.336 m / m, 10
Through a 00-hole rectangular die, i-value 1.0, 20 ° C, 58
% Into a DMF solution. After spinning, the mixture was desolvated and stretched, washed sufficiently, applied with an oil agent, dried and crimped to finally obtain 10d acrylic flat fibers. The obtained acrylic flat fibers were passed through a card and opened to evaluate the feeling and the flat ratio.

【００２１】[0021]

【表２】 [Table 2]

【００２２】比較例９，１０ アクリル系共重合体の分子量を３．４万とする以外、実
施例３と同様にしてアクリル系偏平繊維を製造したが、
強伸度に劣るものであった（比較例９）。アクリル系共
重合体の分子量を５．５万、重合体濃度を２５％とする
以外、実施例３と同様にしてアクリル系偏平繊維を製造
したが、紡糸原液の粘度が高いため紡糸が不安定で、ま
た脱溶媒が大きいため偏平形状が崩れやすい（比較例１
０）。Comparative Examples 9 and 10 Acrylic flat fibers were produced in the same manner as in Example 3 except that the molecular weight of the acrylic copolymer was 34,000.
It was inferior in strong elongation (Comparative Example 9). Acrylic flat fibers were produced in the same manner as in Example 3 except that the molecular weight of the acrylic copolymer was 55,000 and the polymer concentration was 25%. However, spinning was unstable due to high viscosity of the spinning dope. And the flat shape easily collapses due to large desolvation (Comparative Example 1).
0).

【００２３】実施例７ ０．０３８×０．４５６ｍｍ、２５，００２孔の矩形型
口金を用いる以外、実施例３と同様にしてアクリル系偏
平繊維を製造した。得られた繊維の断面は長軸／短軸
（偏平比）１１．５で均一なものであり、一層良好な獣
毛調風合いを有していた。Example 7 An acrylic flat fiber was produced in the same manner as in Example 3 except that a rectangular die having a size of 0.038 × 0.456 mm and 25,002 holes was used. The cross section of the obtained fiber was uniform with a major axis / minor axis (flat ratio) of 11.5, and had a better animal hair texture.

【００２４】[0024]

【発明の効果】本発明の製造方法に従い特定組成のアク
リロニトリル系共重合体を用い、紡糸時の重合体のＤＭ
Ｆ濃度を２５〜３２％に調製し紡糸ドラフト０．６〜
１．５で紡糸する事でハイパイル，ボアー，カーペッ
ト，マット用途に好適な獣毛調風合を有するアクリル系
偏平繊維を工業的容易に製造出来る。According to the production method of the present invention, an acrylonitrile copolymer having a specific composition is used, and the DM of the polymer is spun at the time of spinning.
The F concentration is adjusted to 25 to 32% and the spinning draft is 0.6 to
By spinning at 1.5, acrylic flat fibers having animal-hair-like texture suitable for high pile, bore, carpet, and mat applications can be industrially easily produced.

Claims (3)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 アクリロニトリル８４〜９４．３重量
％、スルホン酸基含有ビニル系モノマー０．７〜３．０
重量％及び他のビニル系モノマー５〜１５重量％よりな
り且つ分子量が４〜５万である共重合体を湿式紡糸して
なるアクリル系繊維であって、繊維横断面の長軸／短軸
比が４．５以上１５以下であることを特徴とするアクリ
ル系扁平繊維。1. Acrylonitrile 84 to 94.3 % by weight, sulfonic acid group-containing vinyl monomer 0.7 to 3.0.
Acrylic fiber obtained by wet spinning a copolymer consisting of 5% to 15% by weight and another vinyl monomer and having a molecular weight of 40,000 to 50,000. Is 4.5 or more and 15 or less . 【請求項２】 アクリロニトリル８４〜９４．３重量
％、スルホン酸基含有ビニル系モノマー０．７〜３．０
重量％及び他のビニル系モノマー５〜１５重量％よりな
り且つ分子量が４〜５万である共重合体を重合し、次い
で該重合体とジメチルホルムアミド／水＝９６／４〜９
４／６（重量比）よりなる重合体濃度２５〜３２％の紡
糸原液を調製し、そして孔形状が矩形の口金を用いてジ
メチルホルムアミド／水系よりなる凝固浴中に紡糸ドラ
フト比０．６〜１．５で紡糸する事を特徴とするアクリ
ル形扁平繊維の製造方法。2. Acrylonitrile 84 to 94.3 % by weight, sulfonic acid group-containing vinyl monomer 0.7 to 3.0.
Of a vinyl monomer having a molecular weight of 40,000 to 50,000, and then polymerized with dimethylformamide / water = 96/4 to 9
A spinning dope having a polymer concentration of 25 to 32% consisting of 4/6 (weight ratio) was prepared, and a spinning draft ratio of 0.6 to 0.6 was poured into a coagulation bath of dimethylformamide / water system using a die having a rectangular hole shape. A method for producing acrylic flat fibers, comprising spinning at 1.5. 【請求項３】 長辺／短辺比（Ａ）が４．５以上１５以
下である矩形状の口金を用いて、下記式の繊維を製造す
る請求項２記載の方法。 ０．８Ａ≦Ｂ≦Ａ3. The long side / short side ratio (A) is 4.5 or more and 15 or less.
3. The method according to claim 2 , wherein the fiber of the following formula is produced using the lower rectangular base. 0.8A ≦ B ≦ A