JP4581297B2 - High strength composite fiber and method for producing the same - Google Patents

Description

ポリフェニレンスルフィド樹脂は一般に、特公昭４５−３３６８号公報で代表される製造法により得られる比較的分子量の小さい重合体と特公昭５２−１２２４０号公報で代表される製造法により得られる本質的に線状で比較的高分子量の重合体等があり、前記特公昭４５−３３６８号公報記載の方法で得られた重合体においては、重合後酸素雰囲気下において加熱することにより、あるいは過酸化物などの架橋剤を添加して加熱することにより高重合度化して用いることも可能であり、本発明においてはいかなる方法により得られたＰＰＳを用いることも可能であるが、芯鞘複合糸の芯鞘界面剥離などを抑制するため特開平４−１７４７２２号公報に示されるように酸洗浄を行ったポリフェニレンスルフィド樹脂を用いることが好ましい。
【００１６】
本発明に用いられる芯成分ポリマー及び鞘成分ポリマーに、本発明の効果を損なわない範囲内で、ポリエチレンテレフタレート、変性ポリエチレンテレフタレート、ポリオレフィン、ポリカーボネート、ポリアリレート、ポリアミド、ポリエステルエーテルケトン、フッソ樹脂等の熱可塑性ポリマーを添加しても良い。また、酸化チタンやカオリン、シリカ、酸化バリウム等の無機物、カーボンブラック、染料や顔料等の着色剤、酸化防止剤、紫外線吸収剤、光安定剤等の各種添剤を添加しても良い。
【００１７】
本発明の高強度複合繊維は強度が１０ｃＮ／ｄｔｅｘ以上及びヤング率が５７０ｃＮ／ｄｔｅｘ以上であることが重要である。強度が１０ｃＮ／ｄｔｅｘ未満及びヤング率が５７０ｃＮ／ｄｔｅｘ未満であると本発明の複合繊維を利用する分野での要求特性を満足出来ず、また汎用繊維との差が小さくなり本発明の高強度複合繊維の優位性がなくなる。
【００１８】
さらに、本発明の高強度複合繊維は鞘成分が非融解性であることが重要である。非融解性であるということは、すなわち固相重合などの加熱処理において繊維間融着を防ぎ工程通過性、安定性を向上させるばかりでなく、繊維自身に摩擦防融性、耐燃焼性、耐火性等を持たせることが出来るため利用範囲の広い繊維とすることが出来るのである。
【００１９】
本発明の高強度複合繊維を製造する方法では、芯成分が溶融液晶形成性ポリエステル、鞘成分がポリフェニレンスルフィド樹脂を原料とする複合繊維を製造するにおいて、溶融紡糸した該複合繊維を酸化処理により鞘成分を非溶融性（４００℃において非溶融）とした後、固相重合することが重要である。固相重合時の繊維間融着による単糸切れ、表面剥離を回避するためには固相重合前に処理をすることが必須であり、また効果も大きい。
【００２０】
さらに、本発明の高強度複合繊維の非溶融化処理方法は、酸化処理でありかつ酸化処理が下記（１）〜（３）の少なくとも１つを含んでいる溶液により処理することが好ましい。
【００２１】
（１）有機過酸化物
（２）次亜塩素酸ナトリウム
（３）過酸化水素
ここでいう、有機過酸とは過蟻酸、過酢酸、過安息香酸、過酪酸、過プロピオン酸、過フタル酸、ｍクロル過安息香酸、過トリクロル酸、過トリクロル酢酸などが上げられる。中でも反応速度の早さ、取り扱いの容易さから過酢酸が特に好ましい。
【００２２】
また、酸化処理は溶液処理が好ましく、糸状による連続処理、巻き取りパッケージによるバッチ処理などが使用できる。
【００２３】
本発明の高強度複合繊維は酸化処理までを公知の複合紡糸機を用いて製造することが出来る。一例としては一般的な２個のエクストルダーを持つ複合紡糸機で溶融液晶形成性ポリエステルとポリフェニレンスルフィド樹脂を個別に溶融し、公知の芯鞘複合口金にて合流させ複合繊維として吐出し、ゴデーローラーで引き取りつつ巻き取ることにより紡糸原糸が製造される。この紡糸原糸を、例えば過酢酸にて酸化処理し、ついで固相重合する事により本発明の高強度複合繊維が製造される。
【００２４】
【実施例】
以下実施例により本発明をより詳細に説明する。なお実施例中の各特性値は次の方法で求めた。
【００２５】
Ａ．融点
融点は、示差走査熱量計（パーキンエルマー社製ＤＳＣ）で観察される主吸熱ピークがあらわれる温度を測定することにより行った。
【００２６】
Ｂ．強伸度、ヤング率
強伸度、ヤング率、はＪＩＳ Ｌ１０１３に準じオリエンテック社製テンシロンＵＣＴ−１００を用いて測定した。
【００２７】
Ｃ．非溶融化の確認
融点顕微鏡を用い４００℃での融解挙動を観察した。
【００２８】
実施例１
芯成分の溶融液晶形成性ポリエステルとしてｐ−アセトキシ安息香酸から生成した構造単位(1)と４，４−ジヒドロキシビフェニルとテレフタル酸から生成した構造単位(2)とエチレングリコールとテレフタル酸から生成したポリエステルの構造単位(3)からなり、構造単位(1)が全体の８０モル％、構造単位(2)と構造単位(3)の合計が２０モル％を占め、構造単位(2)／(3)のモル比が３／５である液晶形成性ポリエステルを用いた。該溶融液晶形成性ポリエステルの融点３１５℃であった。
【００２９】
鞘成分のポリフェニレンスルフィド樹脂として、攪拌機付きオートクレーブに硫化ナトリウム９水塩２５モル、酢酸ナトリウム２．５モルおよびＮ−メチル−２−ピロリドン（以下ＮＭＰと略す）を仕込み、窒素を通じながら徐々に２０５℃まで昇温し、水を留出した。次に反応容器を１８０℃に冷却後、１，４−ジクロロベンゼン２５．３モルならびにＮＭＰを加えて、窒素下に密閉し、２７０℃まで昇温後、２７０℃で２．５時間反応した。冷却後、反応生成物を温水で５回洗浄し、次に１００℃に加熱されＮＭＰ中に投入して、約１時間攪拌し続けたのち、濾過し、さらに熱湯で数回洗浄した。これを９０℃に加熱されたｐＨ４の酢酸水溶液２５リットル中に投入し、約１時間攪拌し続けたのち、濾過し、濾液のｐＨが７になるまで約９０℃のイオン交換水で洗浄後、８０℃で２４時間減圧乾燥して得られたポリフェニレンスルフィド樹脂を用いた。該ポリフェニレンスルフィド樹脂は融点２８２℃であった。
【００３０】
溶融液晶形成性ポリエステル樹脂を芯、ポリフェニレンスルフィド樹脂を鞘として、紡糸温度３２０℃、ノズル径０．１５ｍｍφ、１０ホールの口金より吐出し、紡糸速度１０００ｍ／分で紡糸し、５０デシテックスのフィラメントを得た。この紡糸原糸の性能は強度 ５．６ｃＮ／ｄｔｅｘ、伸度２．１％、弾性率４５０ｃＮ／ｄｔｅｘであった。 この紡糸原糸を連続的に２５％、５０℃の過酢酸溶液中に浸積し酸化処理を行った。このときの処理時間は４０分となるように処理速度を調整した。
【００３１】
得られた糸を、融点顕微鏡を用い４００℃での表面融解挙動を観察したが、融解は認められなかった。この糸を２５０℃で２時間、２８０℃で２時間、３１０℃で６時間窒素ガス雰囲気中で熱処理した。得られた熱処理糸は、繊維間膠着は殆ど無く、巻き返し性も良好であり以下の性能を有していた。
強度 ２０．５ｃＮ／ｄｔｅｘ伸度 ３．２％弾性率５７０ｃＮ／ｄｔｅｘ
比較例１
実施例１の紡糸原糸を用い、酸化処理を行わずに２５０℃で２時間、２８０℃で２時間、３１０℃で６時間窒素ガス雰囲気中で熱処理した。この糸を取り出したところ単糸間融着しており巻き返しが出来ず、繊維として取り出すことが出来なかった。
【００３２】
比較例２
実施例１の紡糸原糸を用い、酸化処理を行わずに２５０℃で２時間、２６０℃で２時間、２７０℃で６時間窒素ガス雰囲気中で熱処理した。この糸は、融点顕微鏡を用い４００℃での表面融解挙動を観察したが、３００℃を越えた時点で融解していた。得られた熱処理糸は、表面は繊維間膠着は殆ど無く以下の性能を有していたが、巻き返し時に内層部に従い糸切れが発生し易くなる傾向を有していた。
【００３３】
強度 １８．２ｃＮ／ｄｔｅｘ、伸度 ３．２％、弾性率５４５ｃＮ／ｄｔｅｘ
実施例２
芯成分の溶融液晶形成性ポリエステルとしてｐ−ヒドロキシ安息香酸６０モル％、４，４−ジヒドロキシビフェニル２０モル％、テレフタル酸１０モル％、イソフタル酸１０モル％である液晶形成性ポリエステルを用いた。該溶融液晶形成性ポリエステルの融点は３１８℃であった。該溶融液晶形成性ポリエステルを用いた以外は実施例１と同様なポリフェニレンスルフィド樹脂、紡糸方法により７０デシテックスのフィラメントを得た。この紡糸原糸を連続的に２５％、５０℃の過酢酸溶液中に浸積し酸化処理を行った。このときの処理時間は４０分となるように処理速度を調整した。
【００３４】
得られた糸を、融点顕微鏡を用い４００℃での表面融解挙動を観察したが、融解は認められなかった。この糸を２５０℃で２時間、２８０℃で２時間、３１０℃で６時間窒素ガス雰囲気中で熱処理した。得られた熱処理糸は、繊維間膠着は殆ど無く、巻き返し性も良好で以下の性能を有していた。
【００３５】
強度 ２５．２ｃＮ／ｄｔｅｘ、伸度 ２．８％、弾性率５９５ｃＮ／ｄｔｅｘ
実施例３
芯成分の溶融液晶形成性ポリエステルとしてｐ−ヒドロキシ安息香酸成、２，６−ヒドロキシナフトエ酸が７２／２８モル％である液晶形成性ポリエステル樹脂を用いた。該溶融液晶形成性ポリエステル樹脂は融点２８０℃であった。該溶融液晶形成性ポリエステルを用いた以外は実施例１と同様なポリフェニレンスルフィド樹脂、紡糸方法により５０デシテックスのフィラメントを得た。得られた紡糸原糸の性能は強度 ８．６ｃＮ／ｄｔｅｘ、伸度２．２％、弾性率４５０ｃＮ／ｄｔｅｘであった。 この紡糸原糸を連続的に２５％、５０℃の過酢酸溶液中に浸積し酸化処理を行った。このときの処理時間は４０分となるように処理速度を調整した。
【００３６】
得られた糸を、融点顕微鏡を用い４００℃での表面融解挙動を観察したが、融解は認められなかった。この紡糸原糸を２５０℃で２時間、２６０℃で２時間、２７０℃で６時間窒素ガス雰囲気中で熱処理した。得られた熱処理糸は、繊維間膠着は殆ど無く、また、巻き返し性も良好で以下の性能を有していた。
【００３７】
強度 １８．４ｃＮ／ｄｔｅｘ、伸度 ２．６％、弾性率５３０ｃＮ／ｄｔｅｘ
【００３８】
【発明の効果】
本発明は、溶融液晶形成性ポリエステルとポリフェニレンスルフィド樹脂の複合繊維において、さらなる物性向上のために固相重合を行うときに発生する繊維間融着の問題点を解決し、従来よりも優れた工程通過性をもつ高強度複合繊維を提供するものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite fiber having high strength and high elasticity excellent in heat resistance, wear resistance and fatigue resistance, and its application field is general industrial materials, particularly ropes, rubber reinforcements, geotextiles, FRCs. It is widely used for applications, computer ribbons, printed circuit board fabrics, air bags, bag filters, screen bags, etc.
[0002]
[Prior art]
The molten liquid crystal forming polyester fiber is known to have a high strength and a high elastic modulus because molecular chains are highly oriented in the fiber axis direction as disclosed in, for example, JP-A-61-174408. Yes. However, since only weak intermolecular forces act in the direction perpendicular to the fiber axis, fibrils are easily generated by friction, causing trouble. In addition, kink bands and buckling phenomenon are likely to occur, and since they tend to concentrate at the extreme places, the fatigue resistance is low. For the purpose of improving these drawbacks, JP-A-1-229815 proposes a composite fiber in which the core component is an aromatic polyester capable of forming an anisotropic melt phase and the sheath component is polyphenylene sulfide. Furthermore, Japanese Patent Laid-Open No. 4-174722 proposes a method for producing a composite fiber that hardly causes interfacial peeling by performing acid washing after polymerization of a polyphenylene sulfide resin and performing composite spinning with a main chain type liquid crystal resin.
[0003]
On the other hand, as a method for making the polyphenylene sulfide resin non-meltable, JP-B-60-35370 discloses methods for improving the surface hardness of articles, JP-A-63-182413, JP-A-2-61110, Japanese Laid-Open Patent Publication No. 5-209368, Japanese Laid-Open Patent Publication No. 5-230712, Japanese Laid-Open Patent Publication No. 5-230760, and the like are disclosed as methods for producing polyphenylene sulfone fibers. In these patents, the strength is generally 3 to 5 g / d. It deals with only a certain level of fiber and does not clearly mention composite fibers.
[0004]
[Problems to be solved by the invention]
As described in JP-A-1-229815 and JP-A-4-174722, it is a fact that fibrillation resistance and wear resistance are improved by using a core-sheath structure. The composite fiber already has sufficient strength and elastic modulus just by spinning, but it is known that the performance can be further improved by relaxation heat treatment or tension heat treatment. However, if this relaxation heat treatment or tension heat treatment is carried out at a temperature higher than the softening temperature of the polyphenylene sulfide resin of the sheath component, fusion of single yarns occurs, and the yarn breakage, surface peeling, etc. due to the fusion part in the subsequent rewinding etc. There was a problem that occurred. Furthermore, in combination with a molten liquid crystal forming polyester having a melting point higher than that of the polyphenylene sulfide resin, solid-state polymerization must be performed at a temperature at which the polyphenylene sulfide resin does not melt. There was a problem that could not be expressed. In addition, as described above, even in the method of making polyphenylene sulfide non-meltable, only fibers having a general strength of 3 to 5 g / d are handled, and composite fibers are not clearly described. However, the present invention, which was insufficient for obtaining the high-strength fiber of the present invention, solved the problems during the solid-phase polymerization of these conventional composite fibers, and had better process passability than before. A high-strength composite fiber having high strength is provided.
[0005]
[Means for Solving the Problems]
That is, this invention has the following structures in order to achieve this subject.
1. In a core-sheath type composite fiber in which the core component is a melt liquid crystal forming polyester and the sheath component is a polyphenylene sulfide resin, the strength of the composite fiber is 10 cN / dtex or more, and the Young's modulus is 570 cN / dtex or more, and the sheath A high-strength conjugate fiber characterized in that the component is non-melting (non-melting at 400 ° C).
2. 2. The high-strength composite fiber according to item 1, wherein the composite fiber is a monofilament of 20 dtex or less.
3. When producing a core-sheath-type composite fiber using a melt liquid crystal-forming polyester as a core component and a polyphenylene sulfide resin as a sheath component, the sheath component is made non-meltable (at 400 ° C.) by subjecting the melt-spun composite fiber to an oxidation treatment. A method for producing a high-strength composite fiber, characterized in that the composite fiber is solid-phase polymerized at a temperature equal to or higher than the melting point of the polyphenylene sulfide resin of the sheath component before being oxidized after the non-melting .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be further described in detail below.
[0008]
The molten liquid crystal forming polyester used in the present invention refers to a polyester that exhibits optical anisotropy when heated and melted. This characteristic can be recognized, for example, by placing the sample on a hot stage, heating and heating in a nitrogen atmosphere, and observing the transmitted light of the sample with a polarizing microscope.
[0009]
Examples of the melt liquid crystal forming polyester used in the present invention include A.I. A polymer of aromatic oxycarboxylic acid; A polymer of aromatic dicarboxylic acid and aromatic diol, aliphatic diol, C.I. Examples thereof include a copolymer of A and B. Moreover, a conventionally well-known method can be used for the polymerization prescription of molten liquid crystal forming polyester.
[0010]
Here, examples of the aromatic oxycarboxylic acid include hydroxybenzoic acid, hydroxynaphthoic acid and the like, and alkyl, alkoxy and halogen substituted products of the above aromatic oxycarboxylic acid. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, etc., or alkyl, alkoxy, and halogen substituted products of the above aromatic dicarboxylic acids Etc.
[0011]
Examples of the aromatic diol include hydroquinone, resorcin, dioxydiphenyl, naphthalenediol, and the above aromatic alkyl, alkoxy, and halogen-substituted products. Aliphatic diols include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, and the like.
[0012]
In the present invention, polyesters obtained by polymerizing the above monomers can be widely used. Preferred examples thereof include a copolymer of a p-hydroxybenzoic acid component and an ethylene terephthalate component, a copolymer of a p-hydroxybenzoic acid component, 4,4-dihydroxybiphenyl, terephthalic acid and / or isophthalic acid. P-hydroxybenzoic acid component and 6-hydroxy 2-naphthoic acid component are copolymerized, p-hydroxybenzoic acid component, 6-hydroxy 2-naphthoic acid component, hydroquinone and terephthalic acid are copolymerized Can be used.
[0013]
The molten liquid crystal-forming polyester used in the present invention preferably has a melting point in the range of 260 to 360 ° C, more preferably a melting point of 270 to 350 ° C. The melting point was measured by measuring the temperature at which the main endothermic peak observed with a differential scanning calorimeter (DSC manufactured by Perkin Elmer) was observed.
[0014]
The polyphenylene sulfide resin referred to in the present invention is a polymer containing 70 mol% or more, preferably 90 mol% or more, of repeating structural units represented by the following chemical formula 1, and if the repeating unit is less than 70 mol%, the heat resistance is impaired. Absent.
[0015]
[Chemical 1]

The polyphenylene sulfide resin is generally composed of a polymer having a relatively low molecular weight obtained by a production method represented by Japanese Patent Publication No. 45-3368 and an essentially linear product obtained by a production method represented by Japanese Patent Publication No. 52-12240. In the polymer obtained by the method described in the above Japanese Patent Publication No. 45-3368, the polymer is heated in an oxygen atmosphere after polymerization, or a peroxide or the like. It is possible to increase the degree of polymerization by adding a crosslinking agent and heating, and in the present invention, it is possible to use PPS obtained by any method, but the core-sheath interface of the core-sheath composite yarn In order to suppress peeling and the like, it is preferable to use a polyphenylene sulfide resin that has been subjected to acid cleaning as disclosed in JP-A-4-174722.
[0016]
The core component polymer and the sheath component polymer used in the present invention are heated within the range not impairing the effects of the present invention, such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyester ether ketone, and fluorine resin. A plastic polymer may be added. Various additives such as inorganic substances such as titanium oxide, kaolin, silica and barium oxide, carbon black, colorants such as dyes and pigments, antioxidants, ultraviolet absorbers and light stabilizers may be added.
[0017]
It is important that the high strength composite fiber of the present invention has a strength of 10 cN / dtex or more and a Young's modulus of 570 cN / dtex or more. If the strength is less than 10 cN / dtex and the Young's modulus is less than 570 cN / dtex, the required characteristics in the field of using the conjugate fiber of the present invention cannot be satisfied, and the difference from the general-purpose fiber becomes small, resulting in the high strength of the present invention. The superiority of the composite fiber is lost.
[0018]
Further, it is important that the sheath component of the high-strength conjugate fiber of the present invention is non-melting. The non-melting property means that not only the inter-fiber fusion is prevented in heat treatment such as solid phase polymerization, but the process passability and stability are improved, and the fiber itself has a friction-fusibility, combustion resistance and fire resistance. Therefore, it is possible to obtain a fiber having a wide range of use.
[0019]
In the method for producing a high-strength conjugate fiber of the present invention, in producing a conjugate fiber using a melt liquid crystal forming polyester as a core component and a polyphenylene sulfide resin as a sheath component, the melt-spun conjugate fiber is sheathed by oxidation treatment. It is important that the components be non-melting (non-melting at 400 ° C.) and then solid phase polymerized. In order to avoid single yarn breakage and surface peeling due to fusion between fibers during solid-phase polymerization, it is essential to perform the treatment before solid-phase polymerization, and the effect is also great.
[0020]
Furthermore, it is preferable that the non-melting treatment method for high-strength conjugate fiber of the present invention is an oxidation treatment and the treatment is performed with a solution containing at least one of the following (1) to (3).
[0021]
(1) Organic peroxide (2) Sodium hypochlorite (3) Hydrogen peroxide Here, organic peracids are formic acid, peracetic acid, perbenzoic acid, perbutyric acid, perpropionic acid, perphthalic acid. M chloroperbenzoic acid, pertrichloric acid, pertrichloroacetic acid and the like. Of these, peracetic acid is particularly preferred because of its fast reaction rate and ease of handling.
[0022]
Further, the oxidation treatment is preferably solution treatment, and continuous treatment using a filamentous shape, batch treatment using a winding package, and the like can be used.
[0023]
The high-strength composite fiber of the present invention can be produced using a known composite spinning machine up to oxidation treatment. As an example, melted liquid crystal forming polyester and polyphenylene sulfide resin are individually melted with a compound spinning machine having two general extruders, merged with a known core-sheath compound mouthpiece, and discharged as a composite fiber. Spinning yarn is manufactured by winding up while taking up. The high-strength conjugate fiber of the present invention is produced by oxidizing this spinning yarn with, for example, peracetic acid, followed by solid-phase polymerization.
[0024]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in an Example was calculated | required with the following method.
[0025]
A. Melting | fusing point melting | fusing point was performed by measuring the temperature at which the main endothermic peak observed with a differential scanning calorimeter (DSC manufactured by Perkin Elmer Co.) appears.
[0026]
B. The high elongation, Young's modulus, high Young's modulus, and Young's modulus were measured using Tensilon UCT-100 manufactured by Orientec Corporation according to JIS L1013.
[0027]
C. Confirmation of non-melting Melting behavior at 400 ° C. was observed using a melting point microscope.
[0028]
Example 1
Polyester produced from structural unit (1) produced from p-acetoxybenzoic acid, structural unit (2) produced from 4,4-dihydroxybiphenyl and terephthalic acid, ethylene glycol and terephthalic acid The structural unit (1) is 80 mol% of the total, and the total of the structural unit (2) and the structural unit (3) occupies 20 mol%, and the structural unit (2) / (3) A liquid crystal forming polyester having a molar ratio of 3/5 was used. The melting point of the molten liquid crystal forming polyester was 315 ° C.
[0029]
As a polyphenylene sulfide resin as a sheath component, 25 mol of sodium sulfide nonahydrate, 2.5 mol of sodium acetate and N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) are charged into an autoclave equipped with a stirrer and gradually heated to 205 ° C. through nitrogen. The water was distilled off. Next, the reaction vessel was cooled to 180 ° C., 25.3 mol of 1,4-dichlorobenzene and NMP were added, sealed under nitrogen, heated to 270 ° C., and reacted at 270 ° C. for 2.5 hours. After cooling, the reaction product was washed 5 times with warm water, then heated to 100 ° C. and poured into NMP, stirred for about 1 hour, filtered, and washed several times with hot water. This was put into 25 liters of an acetic acid aqueous solution of pH 4 heated to 90 ° C., and stirred for about 1 hour, filtered, washed with ion-exchanged water of about 90 ° C. until the pH of the filtrate reached 7, A polyphenylene sulfide resin obtained by drying under reduced pressure at 80 ° C. for 24 hours was used. The polyphenylene sulfide resin had a melting point of 282 ° C.
[0030]
Using melted liquid crystal forming polyester resin as the core and polyphenylene sulfide resin as the sheath, spinning temperature is 320 ° C, nozzle diameter is 0.15mmφ, 10 holes are spouted, spinning at spinning speed of 1000m / min, and 50 decitex filament is obtained. It was. The performance of the spinning yarn was a strength of 5.6 cN / dtex, an elongation of 2.1%, and an elastic modulus of 450 cN / dtex. This spinning yarn was continuously immersed in a peracetic acid solution at 25% and 50 ° C. for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.
[0031]
The resulting yarn was observed for surface melting behavior at 400 ° C. using a melting point microscope, but no melting was observed. The yarn was heat-treated in a nitrogen gas atmosphere at 250 ° C. for 2 hours, 280 ° C. for 2 hours, and 310 ° C. for 6 hours. The obtained heat treated yarn had almost no interfiber sticking, good rewinding property, and had the following performance.
Strength 20.5 cN / dtex Elongation 3.2% Elastic modulus 570 cN / dtex
Comparative Example 1
The spinning base yarn of Example 1 was heat-treated in a nitrogen gas atmosphere at 250 ° C. for 2 hours, 280 ° C. for 2 hours, and 310 ° C. for 6 hours without performing oxidation treatment. When this yarn was taken out, it was fused between single yarns and could not be rewound, and could not be taken out as a fiber.
[0032]
Comparative Example 2
The spinning base yarn of Example 1 was heat-treated in a nitrogen gas atmosphere at 250 ° C. for 2 hours, 260 ° C. for 2 hours, and 270 ° C. for 6 hours without performing oxidation treatment. The yarn was observed for surface melting behavior at 400 ° C. using a melting point microscope, but was melted when the temperature exceeded 300 ° C. The obtained heat-treated yarn had almost no interfiber adhesion on the surface and had the following performance, but it had a tendency that yarn breakage was likely to occur according to the inner layer portion during rewinding.
[0033]
Strength 18.2 cN / dtex, elongation 3.2%, elastic modulus 545 cN / dtex
Example 2
A liquid crystal forming polyester having 60 mol% of p-hydroxybenzoic acid, 20 mol% of 4,4-dihydroxybiphenyl, 10 mol% of terephthalic acid, and 10 mol% of isophthalic acid was used as the melt liquid crystal forming polyester of the core component. The melting point of the molten liquid crystal forming polyester was 318 ° C. A 70 decitex filament was obtained by the same polyphenylene sulfide resin and spinning method as in Example 1 except that the molten liquid crystal forming polyester was used. This spinning yarn was continuously immersed in a peracetic acid solution at 25% and 50 ° C. for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.
[0034]
The resulting yarn was observed for surface melting behavior at 400 ° C. using a melting point microscope, but no melting was observed. The yarn was heat-treated in a nitrogen gas atmosphere at 250 ° C. for 2 hours, 280 ° C. for 2 hours, and 310 ° C. for 6 hours. The obtained heat-treated yarn had almost no interfiber sticking, good rewinding property, and had the following performance.
[0035]
Strength 25.2 cN / dtex, elongation 2.8%, elastic modulus 595 cN / dtex
Example 3
A liquid crystal forming polyester resin having 72/28 mol% of p-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid was used as the melt liquid crystal forming polyester of the core component. The molten liquid crystal forming polyester resin had a melting point of 280 ° C. A 50 decitex filament was obtained by the same polyphenylene sulfide resin and spinning method as in Example 1 except that the molten liquid crystal forming polyester was used. The obtained spinning yarn had a strength of 8.6 cN / dtex, an elongation of 2.2%, and an elastic modulus of 450 cN / dtex. This spinning yarn was continuously immersed in a peracetic acid solution at 25% and 50 ° C. for oxidation treatment. The processing speed was adjusted so that the processing time at this time was 40 minutes.
[0036]
The resulting yarn was observed for surface melting behavior at 400 ° C. using a melting point microscope, but no melting was observed. This spinning yarn was heat-treated in a nitrogen gas atmosphere at 250 ° C. for 2 hours, 260 ° C. for 2 hours, and 270 ° C. for 6 hours. The obtained heat-treated yarn had almost no interfiber sticking, had good rewinding properties, and had the following performance.
[0037]
Strength 18.4 cN / dtex, elongation 2.6%, elastic modulus 530 cN / dtex
[0038]
【The invention's effect】
The present invention solves the problem of inter-fiber fusion that occurs when solid-phase polymerization is performed in order to further improve physical properties in a composite fiber of melted liquid crystal forming polyester and polyphenylene sulfide resin. The present invention provides a high-strength composite fiber having permeability.

Claims (3)

In a core-sheath type composite fiber in which the core component is a melt liquid crystal forming polyester and the sheath component is a polyphenylene sulfide resin, the strength of the composite fiber is 10 cN / dtex or more, and the Young's modulus is 570 cN / dtex or more, and the sheath A high-strength conjugate fiber characterized in that the component is non-melting (non-melting at 400 ° C). The high-strength conjugate fiber according to claim 1, wherein the conjugate fiber is a monofilament having a fineness of 20 dtex or less. When producing a core-sheath-type composite fiber using a melt liquid crystal-forming polyester as a core component and a polyphenylene sulfide resin as a sheath component, the sheath component is made non-meltable (at 400 ° C.) by subjecting the melt-spun composite fiber to an oxidation treatment. A method for producing a high-strength composite fiber, characterized in that the composite fiber is solid-phase polymerized at a temperature equal to or higher than the melting point of the polyphenylene sulfide resin of the sheath component before being oxidized after the non-melting.