JP2004149957A - Spun yarn comprising polybenzazole fibers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber structure constituting protecting materials, protecting clothes and industrial materials which scarcely deteriorate the strengths even when exposed to high temperature and high humidity for long periods, and especially to provide a spun yarn comprising polybenzazole fibers having excellent durability. <P>SOLUTION: This fiber structure constituting the protecting materials, the protecting clothes and the industrial materials which scarcely deteriorate the strengths even when exposed to high temperature and high humidity for long periods, especially the spun yarn comprising the polybenzazole fibers having excellent durability are obtained by using the polybenzazole fibers to which a basic organic compound, particularly a basic organic compound selected from p-phenylene diamine, m-phenylene diamine and their mixture is imparted in the form of the monomer or its condensation product. <P>COPYRIGHT: (C)2004,JPO

Description

【００１１】
ポリベンザゾール繊維は、ＰＢＺポリマーを含有するドープより製造されるが、当該ドープを調製するための好適な溶媒としては、クレゾールやそのポリマーを溶解しうる非酸化性の酸が挙げられる。好適な非酸化性の酸の例としては、ポリリン酸、メタンスルホン酸および高濃度の硫酸あるいはそれらの混合物が挙げられる。中でもポリリン酸及びメタンスルホン酸、特にポリリン酸が好適である。
【００１２】
ドープ中のポリマー濃度は好ましくは少なくとも約７重量％であり、より好ましくは少なくとも１０重量％、特に好ましくは少なくとも１４重量％である。最大濃度は、例えばポリマーの溶解性やドープ粘度といった実際上の取り扱い性により限定される。それらの限界要因のために、ポリマー濃度は通常では２０重量％を越えることはない。
【００１３】
本発明において、好適なポリマーまたはコポリマーとドープは公知の方法で合成される。例えばＷｏｌｆｅらの米国特許第４，５３３，６９３号明細書（１９８５．８．６）、Ｓｙｂｅｒｔらの米国特許第４，７７２，６７８号明細書（１９８８．９．２２）、Ｈａｒｒｉｓの米国特許第４，８４７，３５０号明細書（１９８９．７．１１）またはＧｒｅｇｏｒｙらの米国特許第５，０８９，５９１号明細書（１９９２．２．１８）に記載されている。要約すると、好適なモノマーは非酸化性で脱水性の酸溶液中、非酸化性雰囲気で高速撹拌及び高剪断条件のもと約６０℃から２３０℃までの段階的または任意の昇温速度で温度を上げることで反応させられる。
【００１４】
このようにして得られるドープを紡糸口金から押し出し、空間で引き伸ばしてフィラメントに形成される。好適な製造法は先に述べた参考文献や米国特許第５，０３４，２５０号明細書に記載されている。紡糸口金を出たドープは紡糸口金と洗浄バス間の空間に入る。この空間は一般にエアギャップと呼ばれているが、空気である必要はない。この空間は、溶媒を除去すること無く、かつ、ドープと反応しない溶媒で満たされている必要があり、例えば空気、窒素、アルゴン、ヘリウム、二酸化炭素等が挙げられる。
【００１５】
紡糸後のフィラメントは、過度の延伸を避けるために洗浄され溶媒の一部が除去される。そして、更に洗浄され、適宜水酸化ナトリウム、水酸化カルシウム、水酸化カリウム等の無機塩基で中和され、ほとんどの溶媒は除去される。ここでいう洗浄とは、ポリベンザゾールポリマーを溶解している鉱酸に対し相溶性であり、ポリベンザゾールポリマーに対して溶媒とならない液体に繊維またはフィラメントを接触させ、ドープから酸溶媒を除去することである。鉱酸とは、メタンスルフォン酸またはポリリン酸である。好適な洗浄液体としては、水や水と酸溶媒との混合物がある。フィラメントは、好ましくは残留鉱酸金属原子濃度が重量で８０００ｐｐｍ以下、更に好ましくは５０００ｐｐｍ以下に洗浄される。繊維中に残留する無機塩基と鉱酸の化学量論比が０．９〜１．６：１であることが望ましい。その後、フィラメントは、乾燥、熱処理、巻き取り等が必要に応じて行われる。
【００１６】
本発明に係る耐久性に優れたポリベンザゾール繊維からなる紡績糸の第一の特徴は、ポリベンザソール繊維中に塩基性有機化合物をモノマーあるいは縮合物の形で含んでいることであり、これにより、温度８０℃相対湿度８０％雰囲気下で７００時間暴露した後の引張強度保持率が７０％以上、好ましくは７５％以上を達成できる。ここでいう塩基性有機化合物とは、例えば芳香族アミンのように塩基性を示す有機化合物であれば特に限定されることはなく、１−ナフチルアミン−４−スルフォン酸ナトリウム、１−アミノナフタレン、１，５−ジアミノナフタレン、β−フェニルエチルアミン、ｐ−フェニレンジアミン、ｏ−フェニレンジアミン、ｍ−フェニレンジアミン、重炭酸アミノグアニジン、１，３−ビス（２−ベンゾチアゾリル）グアニジン、１，３−ジフェニルグアニジン、１，３−ジ（ｏ−トルイル）グアニジン、１，２，３−トリフェニルグアニジン、２−（２−ヒドロキシ−５−メチルフェニル）ベンゾトリアゾール、３−アミノ−１，２，４−トリアゾール、２−［２−ヒドロキシ−３−（３，４，５，６−テトラヒドロフタルイミドーメチル）−５−メチルフェニル］ベンゾトリアゾール、２−（３，５−ジ−ｔｅｒｔ−ブチル−２−ヒドロキシフェニル）ベンゾトリアゾール、キナゾリン−２，４−ジオン、ピペラジン、アニリン、ｏ−ヒドロキシアニリン、ｏ−フェノキシアニリン、ｐ−ヒドロキシアニリン、ピリジン、キノリン、イソシアヌル酸等があげられる。
【００１７】
塩基性有機化合物を付与する場合、糸中の水分率が２０％以下になる履歴を一度も与えることなしに塩基性有機化合物を付与することが好ましい。糸中の水分率が２０％以下になる履歴を一度でも与えてしまうと、繊維表面の細孔が細くなり、繊維表面が緻密になってしまうため、塩基性有機化合物を糸内部まで付与することが難しくなる。具体的な付与方法としては、製造工程において紡糸口金からドープを押し出した後から乾燥するまでの間でガイドオイリング方式、シャワリング方式、ディップ方式などで付与する方法、あるいは、糸を乾燥させずに巻き取って、塩基性有機化合物の溶液に浸漬して付与する方法などが挙げられるが、高温かつ高湿度下に長時間暴露した後の強度保持率を維持するためには、糸を乾燥させずに巻き取って、塩基性有機化合物の溶液に長時間浸漬して付与することが好ましい。
【００１８】
本発明に係る耐久性に優れたポリベンザゾール繊維からなる紡績糸の第二の特徴は、繊維中にｐ−フェニレンジアミン、ｍ−フェニレンジアミン、あるいはその混合物から選択される塩基性有機化合物をモノマーあるいは縮合物の形で含んでいることであり、これにより、温度８０℃相対湿度８０％雰囲気下で７００時間暴露した後の引張強度保持率が７０％以上、好ましくは７５％以上を達成できる。他の塩基性有機化合物でも高温かつ高湿度下に長時間暴露されることによる強度低下を抑制する効果はあるが、中でもフェニレンジアミンが、その効果が大きい。フェニレンジアミンの付与量は１０％以下、好ましくは８％以下、更に好ましくは２〜６％であることが好ましい。１０％を超えるとフェニレンジアミン付与量の増加によるフィラメント繊度の増加で初期の糸強度が低くなるため好ましくない。
【００１９】
フェニレンジアミンを付与する場合も、上記に述べた塩基性化合物を付与する場合と同様、糸中の水分率が２０％以下になる履歴を一度も与えることなしに付与することが好ましい。糸中の水分率が２０％以下になる履歴を一度でも与えてしまうと、繊維表面の細孔が細くなり、繊維表面が緻密になってしまうため、フェニレンジアミンを糸内部まで付与することが難しくなる。具体的な付与方法として、紡糸口金からドープを押し出した後から乾燥するまでの間でガイドオイリング方式、シャワリング方式、ディップ方式により付与する方法、あるいは、糸を乾燥させずに巻き取って、フェニレンジアミン水溶液に浸漬して付与する方法などが挙げられるが、高温かつ高湿度下に長時間暴露した後の強度保持率を維持するためには、糸を乾燥させずに巻き取って、フェニレンジアミン水溶液に長時間浸漬して付与することが好ましく、さらに好ましくはチーズ染色方式により長時間処理を行い、フェニレンジアミンを糸内部に十分に付与するのが良い。
【００２０】
ｐ−フェニレンジアミンとｍ−フェニレンジアミンの配合比はｐ−フェニレンジアミン：ｍ−フェニレンジアミン＝４：６〜０：１０であること、すなわちｐ−フェニレンジアミンに対してｍ−フェニレンジアミンの方が多いことが好ましい。
ｐ−フェニレンジアミンはｍ−フェニレンジアミンと比較して水中での酸化縮合が格段に進みやすく水中ですぐに縮合度が上がってしまうため、フェニレンジアミン縮合物が繊維内部のボイド中に入りにくくなり、ボイド中をフェニレンジアミン縮合物で十分に満たし安定化させることが困難になり、その結果、温度８０℃相対湿度８０％雰囲気下で７００時間暴露した後の引張強度保持率が７０％以上を達成することが困難となる場合がある。ｍ−フェニレンジアミンの酸化縮合が進みにくい性質を利用して、ｐ−フェニレンジアミンに対してｍ−フェニレンジアミンを多く配合することでボイド中にフェニレンジアミン縮合物を安定的に付与することが可能となる。ただし、ｍ−フェニレンジアミンのみでは酸化縮合が進みにくく、付与処理に非常に長時間必要となり生産性が悪くなるため、あまり好ましくない。酸化縮合を進めるために高温で処理する方法も挙げられるが、処理時に糸強度の低下を招くことがあるため、あまり好ましくない。
【００２１】
繊維内部における塩基性有機化合物の化学的な作用については明確には分かっていない。単純に、塩基性有機化合物のモノマーあるいは縮合体がポリベンザゾール繊維中のミクロボイド間に満たされているため、高温かつ高湿度下に長時間暴露されても外からの水蒸気がＰＢＺ分子に到達しにくくなり強度低下が起こりにくくなるのか、あるいは、ポリベンザゾール繊維中に残留している鉱酸あるいはその縮合物が水分により解離して放出した水素イオンを塩基性物質が捕捉して系内を中性化することにより強度低下を抑制しているのか、あるいは、共役長の長い塩基性有機化合物の縮合体が何らかの理由により繊維中で発生したラジカルを捕捉して系内を安定化させることにより強度低下を抑制しているのか、などが推定されるが、本発明はこの考察に拘束されるものではない。
【００２２】
このようにして得られたポリベンザゾール繊維からなる紡績糸は、温度８０℃相対湿度８０％雰囲気下で７００時間暴露した後の引張強度保持率が７０％以上、好ましくは７５％以上といった耐久性に優れたものとなる。さらに、得られたポリベンザゾール繊維からなる紡績糸を用いることで、耐久性に優れる防護材料、防護衣料、および産業用資材を構成する繊維構造物を得ることが可能となる。
【００２３】
本発明の対象となる紡績糸とは、他の繊維とブレンドした複合紡績糸も本発明の範囲である。他の繊維とは、天然繊維、有機繊維、金属繊維、無機繊維、鉱物繊維等である。さらに、ブレンド方法について特に限定されるものではなく、一般的な混打綿混紡や、芯鞘構造を有するものでもよい。
【００２４】
【実施例】
以下に実例を用いて本発明を具体的に説明するが、本発明はもとより下記の実施例によって制限を受けるものではなく、前後記の主旨に適合し得る範囲で適当に変更を加えて実施することも勿論可能であり、それらはいずれも本発明の技術範囲に含まれる。
【００２５】
（高温かつ高湿度下における強度低下の評価方法）
高温かつ高湿度下における強度低下の評価は、サンプルを恒温恒湿器中で高温かつ高湿度保管処理した後、標準状態（温度：２０±２℃、相対湿度６５±２％）の試験室内に取り出し、３０分以内に引張試験を実施し、処理前の強度に対する処理後の強度保持率で評価を行った。なお、高温高湿度下での保管試験にはヤマト科学社製Ｈｕｍｉｄｉｃ Ｃｈａｍｂｅｒ １Ｇ４３Ｍを使用し、恒温恒湿器中に光が入らないよう完全に遮光して、８０℃、相対湿度８０％の条件下にて７００時間処理を実施した。
【００２６】
強度保持率は、高温高湿度保管前後の引張強度を測定し、高温高湿度保管試験後の引張強度の測定は、ＪＩＳ−Ｌ１０１５に準じて引張試験機（島津製作所制、形式ＡＧ−５０ＫＮＧ）にて測定した。
【００２７】
（繊維中の残留リン酸濃度、ナトリウム濃度の評価方法）
繊維中の残留リン濃度は、試料をペレット状に固めて蛍光Ｘ線測定装置（フィリップスＰＷ１４０４／ＤＹ６８５）を用いて測定し、ナトリウム濃度は中性子活性化分析法で測定した。
【００２８】
水分率は、乾燥前重量：Ｗ０（ｇ）、乾燥後重量：Ｗ１（ｇ）から、下記の計算式に従って算出した。なお、乾燥は２００℃１時間の条件で実施した。
（式）水分率（％）＝（Ｗ０−Ｗ１）／Ｗ１×１００
【００２９】
（実施例１）
３０℃のメタンスルホン酸溶液で測定した固有粘度が３０ｄＬ／ｇのポリパラフェニレンベンゾビスオキサゾール１４重量％と五酸化リン含有率８４．３％のポリリン酸から成る紡糸ドープを紡糸温度１７５℃で孔径０．１８ｍｍ、孔数１６６のノズルから押し出してフィラメントとした後、適当な位置で収束させてマルチフィラメントにするように配置された第１洗浄浴中に浸漬し、凝固させた。紡糸ノズルと第１洗浄浴の間のエアギャップには、より均一な温度でフィラメントが引き伸ばされるようにクエンチチャンバーを設置した。クエンチ温度は６０℃とした。その後、ポリベンザゾール繊維中の残留リン濃度が５０００ｐｐｍ以下になるまで水洗し、乾燥させずにフィラメントを紙管に巻き取った。なお、巻取速度は２００ｍ／分、紡糸延伸倍率は４０とし、フィラメントの巻き量は１５００ｍとした。このようにして巻き取ったフィラメントの単糸繊度は１．５ｄｐｆ（ｄｅｎｉｅｒ／ｆｉｌａｍｅｎｔ）、その直径は１１．５μｍであり、水分率は５０％であった。
巻き取った糸を１％ＮａＯＨ水溶液で１０秒間中和し、その後３０秒間水洗した後、乾燥させずに多孔質樹脂ボビンに巻き取った。巻き取った糸の水分率は５０％であった。１２Ｌの水に、ｍ−フェニレンジアミン２．８ｇとｐ−フェニレンジアミン１．２ｇを溶解した液を図１に示す装置に入れ、巻き取った糸を入れて常温（２０℃）で２４時間液を循環した後、さらに装置内の液を純水に置換して常温（２０℃）で１時間かけて循環した。その後、装置から糸を取り出して８０℃にて４時間乾燥した。なお、液の循環は液中に空気を供給しながら実施した。得られた糸の繊維中の残留リン濃度、ナトリウム濃度を測定した結果、リン濃度は１９００ｐｐｍ、ナトリウム濃度は７６０ｐｐｍ、Ｎａ／Ｐモル比は０．５４であった。続いて得られたポリベンザソール繊維より、カット長５１ｍｍのステープルファイバーを製作し、撚り係数３．５に設定し、綿番手で２０Ｎｅの紡績糸を製作した。得られた紡績糸の引張強度は９．８ｃＮ／ｄｔｅｘであった。このように得られた紡績糸の高温高湿保管試験（８０℃、８０ＲＨ％）を行った結果、強度保持率は７７％であった。
【００３０】
（比較例１）
ポリベンザゾール繊維中の残留リン濃度を５０００ｐｐｍ以下になるまで水洗し乾燥させずにフィラメントを紙管に巻き取るところまでは実施例１と同様に行った。
巻き取った糸を１％ＮａＯＨ水溶液で１０秒間中和し、その後３０秒間水洗した後、８０℃にて４時間乾燥した。得られた糸の繊維中の残留リン濃度、ナトリウム濃度を測定した結果、リン濃度は４７００ｐｐｍ、ナトリウム濃度は３３００ｐｐｍ、Ｎａ／Ｐモル比は０．９５であった。得られたポリベンザソール繊維より、カット長５１ｍｍのステープルファイバーを製作し、撚り係数３．５に設定し、綿番手で２０Ｎｅの紡績糸を製作した。得られた紡績糸の引張強度は９．１ｃＮ／ｄｔｅｘであった。続いて、得られた紡績糸の高温高湿保管試験（８０℃、８０ＲＨ％）を行った結果、強度保持率は６０％であった。
【００３１】
以上の結果から、比較例と比べ、実施例のポリベンザゾール繊維からなる紡績糸は高温高湿度下に暴露した後の強度保持率が非常に高いことがわかる。
【００３２】
【発明の効果】
本発明によると、高温高湿度下に長時間暴露された場合であっても強度を充分に維持することができる防護材料、防護衣料および産業用資材等の繊維構造物に好適なポリベンザゾール繊維からなる紡績糸が提供できる。
【図面の簡単な説明】
【図１】チーズ染色装置例の概要図
【符号の説明】
１：処理層、２：処理液、３：綾巻きされた未乾燥糸、４：透水性がある多孔質ボビン、５：ボビンの栓、６：処理液循環ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is applied to protective materials and protective clothing used for high-strength, high heat-resistant fire-fighting clothing, heat-resistant clothing, work clothes, and the like, and high-strength, high-heat-resistant transport materials, cushion materials, coating protective materials, and the like. The present invention relates to a fiber structure constituting an industrial material to be used, and more particularly to a spun yarn made of polybenzazole fiber having excellent durability when exposed to high temperature and high humidity.
[0002]
[Prior art]
As a fiber having high strength and high heat resistance, polybenzazole fiber composed of polybenzoxazole or polybenzothiazole or a copolymer thereof is known.
Spun yarns using polybenzazole fibers are also known.
[0003]
Usually, after extruding the dope containing the polymer or copolymer and the acid solvent from the spinneret, the polybenzazole fiber is immersed in a coagulable fluid (water or a mixture of water and an inorganic acid) to coagulate. After thoroughly washing in a washing bath to remove most of the solvent, the solution passes through an aqueous solution of an inorganic base such as sodium hydroxide to neutralize the acid remaining in the yarn without being extracted, and then dried. Obtained by:
[0004]
As described above, the polybenzazole fiber produced as described above has excellent mechanical properties such as strength and elastic modulus, and thus is used also as a fiber structure constituting protective materials, protective clothing and industrial materials. As mentioned above, further improvement in performance is expected, especially spinning of polybenzazole fiber, which can maintain sufficient strength when exposed to high temperature and high humidity for a long time. Thread was strongly desired.
[0005]
[Problems to be solved by the invention]
Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a spun yarn made of a polybenzazole fiber having a small strength decrease even when exposed to high temperature and high humidity for a long time. In particular, the present invention provides a spun yarn used for a fiber structure constituting a protective material, protective clothing and industrial materials.
[0006]
[Means for Solving the Problems]
The present inventor has proposed a poly (aniline) obtained by adding a basic organic compound, in particular, a basic organic compound selected from p-phenylenediamine, m-phenylenediamine or a mixture thereof to a yarn in the form of a monomer or a condensate thereof. The use of spun yarn made of benzasol fiber can provide a spun yarn used for a fiber structure constituting a protective material, protective garment, and industrial material with a small decrease in strength even when exposed to high temperature and high humidity for a long time. And have led to the present invention.
[0007]
That is, the present invention has the following configuration.
1. A spun yarn comprising at least a part of a polybenzazole fiber having excellent durability and having a tensile strength retention of 70% or more after being exposed in an atmosphere at a temperature of 80 ° C. and a relative humidity of 80% for 700 hours.
2. 2. A spun yarn according to the above item 1, wherein the polybenzazole fiber contains a basic organic compound in the form of a monomer or a condensate.
3. 3. The spun yarn according to the above item 2, wherein the basic organic compound is p-phenylenediamine, m-phenylenediamine, or a mixture thereof.
Hereinafter, the present invention will be described in detail.
[0008]
The polybenzazole fiber refers to a fiber made of a polybenzazole polymer, and the polybenzazole (hereinafter, also referred to as PBZ) refers to a polybenzoxazole (hereinafter, also referred to as PBO) homopolymer, a polybenzothiazole (hereinafter, PBT). (Hereinafter also referred to as a homopolymer) and a random, sequential or block copolymer of PBO and PBT.
[0009]
The structural unit contained in the PBZ polymer is preferably selected from a lyotropic liquid crystal polymer. The polymer consists of the monomer units described in structural formulas (a) to (f).
[0010]
Embedded image

[0011]
Polybenzazole fibers are manufactured from a dope containing a PBZ polymer, and suitable solvents for preparing the dope include cresol and non-oxidizing acids capable of dissolving the polymer. Examples of suitable non-oxidizing acids include polyphosphoric acid, methanesulfonic acid and high concentrations of sulfuric acid or mixtures thereof. Among them, polyphosphoric acid and methanesulfonic acid, particularly polyphosphoric acid, are preferred.
[0012]
The polymer concentration in the dope is preferably at least about 7% by weight, more preferably at least 10% by weight, particularly preferably at least 14% by weight. The maximum concentration is limited by practical handling properties such as, for example, polymer solubility and dope viscosity. Because of these limiting factors, the polymer concentration does not usually exceed 20% by weight.
[0013]
In the present invention, suitable polymers or copolymers and dopes are synthesized by known methods. For example, Wolfe et al., U.S. Pat. No. 4,533,693 (1985.8.6); Sybert et al., U.S. Pat. No. 4,772,678 (1988.9.22); Harris U.S. Pat. No. 4,847,350 (1989.7.11) or US Pat. No. 5,089,591 to Gregory et al. (1992.2.18). In summary, suitable monomers are prepared in a non-oxidizing, dehydrating acid solution, in a non-oxidizing atmosphere, under high speed stirring and high shear conditions, at a stepwise or optional heating rate from about 60 ° C to 230 ° C. Can be reacted by raising
[0014]
The dope thus obtained is extruded from a spinneret and stretched in space to form a filament. Suitable processes are described in the references mentioned above and in U.S. Pat. No. 5,034,250. The dope which has left the spinneret enters the space between the spinneret and the washing bath. This space is commonly referred to as an air gap, but need not be air. This space must be filled with a solvent that does not react with the dope without removing the solvent, and examples thereof include air, nitrogen, argon, helium, and carbon dioxide.
[0015]
The spun filaments are washed and some of the solvent is removed to avoid overdrawing. Then, it is further washed and appropriately neutralized with an inorganic base such as sodium hydroxide, calcium hydroxide, potassium hydroxide or the like, and most of the solvent is removed. Washing here refers to removing the acid solvent from the dope by contacting the fiber or filament with a liquid that is compatible with the mineral acid in which the polybenzazole polymer is dissolved and does not become a solvent for the polybenzazole polymer. It is to be. Mineral acids are methanesulfonic acid or polyphosphoric acid. Suitable cleaning liquids include water or a mixture of water and an acid solvent. The filaments are preferably washed to a residual mineral acid metal atom concentration of less than 8000 ppm by weight, more preferably less than 5000 ppm. It is desirable that the stoichiometric ratio between the inorganic base and the mineral acid remaining in the fiber is 0.9 to 1.6: 1. Thereafter, the filament is subjected to drying, heat treatment, winding, and the like as necessary.
[0016]
The first feature of the spun yarn composed of the highly durable polybenzazole fiber according to the present invention is that the polybenzazole fiber contains a basic organic compound in a monomer or condensate form in the polybenzasol fiber. Thereby, the tensile strength retention after exposure for 700 hours in an atmosphere at a temperature of 80 ° C. and a relative humidity of 80% can achieve 70% or more, preferably 75% or more. The basic organic compound referred to here is not particularly limited as long as it is an organic compound exhibiting basicity such as an aromatic amine, for example, 1-naphthylamine-4-sodium sulfonate, 1-aminonaphthalene, , 5-Diaminonaphthalene, β-phenylethylamine, p-phenylenediamine, o-phenylenediamine, m-phenylenediamine, aminoguanidine bicarbonate, 1,3-bis (2-benzothiazolyl) guanidine, 1,3-diphenylguanidine, 1,3-di (o-toluyl) guanidine, 1,2,3-triphenylguanidine, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 3-amino-1,2,4-triazole, 2 -[2-hydroxy-3- (3,4,5,6-tetrahydrophthalimido-methyl)- -Methylphenyl] benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, quinazoline-2,4-dione, piperazine, aniline, o-hydroxyaniline, o-phenoxyaniline, p-Hydroxyaniline, pyridine, quinoline, isocyanuric acid and the like.
[0017]
When a basic organic compound is applied, it is preferable to apply the basic organic compound without giving a history that the water content in the yarn becomes 20% or less. If the history of the water content in the yarn being 20% or less is given even once, the pores on the fiber surface become thinner and the fiber surface becomes denser. Becomes difficult. As a specific application method, a guide oiling method, a showering method, a method of applying a dip method or the like during a period from extruding a dope from a spinneret to drying in a manufacturing process, or without drying the yarn. Winding, a method of applying by immersing in a solution of a basic organic compound and the like, but in order to maintain the strength retention after long-term exposure to high temperature and high humidity, without drying the yarn It is preferable to apply it by winding it in a solution of a basic organic compound for a long time.
[0018]
The second feature of the spun yarn made of polybenzazole fiber having excellent durability according to the present invention is that a basic organic compound selected from p-phenylenediamine, m-phenylenediamine, or a mixture thereof is contained in the fiber as a monomer. Alternatively, it is contained in the form of a condensate, whereby the retention of tensile strength after exposure for 700 hours in an atmosphere of a temperature of 80 ° C. and a relative humidity of 80% can be at least 70%, preferably at least 75%. Other basic organic compounds also have the effect of suppressing a decrease in strength due to prolonged exposure to high temperature and high humidity, but phenylenediamine is particularly effective. The amount of phenylenediamine provided is preferably 10% or less, preferably 8% or less, and more preferably 2 to 6%. If it exceeds 10%, the initial yarn strength becomes low due to an increase in filament fineness due to an increase in the amount of phenylenediamine applied, which is not preferable.
[0019]
Also in the case of applying phenylenediamine, similarly to the case of applying the above-described basic compound, it is preferable to provide without giving a history that the water content in the yarn becomes 20% or less. If the history that the water content in the yarn is 20% or less is given even once, the pores on the fiber surface become thinner and the fiber surface becomes denser, so it is difficult to apply phenylenediamine to the inside of the yarn. Become. As a specific application method, a method of applying a guide oiling method, a showering method, a dipping method from after extruding the dope from the spinneret to drying, or winding the yarn without drying, phenylene Examples include a method of immersing the yarn in an aqueous diamine solution.However, in order to maintain the strength retention after prolonged exposure to high temperature and high humidity, the yarn is wound without drying and the aqueous phenylenediamine solution is used. It is preferable to apply for a long time by immersing the phenol in the yarn, and more preferably to perform a long-term treatment by a cheese dyeing method to sufficiently apply phenylenediamine to the inside of the yarn.
[0020]
The compounding ratio of p-phenylenediamine and m-phenylenediamine is p-phenylenediamine: m-phenylenediamine = 4: 6 to 0:10, that is, m-phenylenediamine is more than p-phenylenediamine. Is preferred.
As compared with m-phenylenediamine, p-phenylenediamine is much easier to undergo oxidative condensation in water, and the degree of condensation increases immediately in water. It becomes difficult to sufficiently fill and stabilize the voids with the phenylenediamine condensate, and as a result, a tensile strength retention of 70% or more after exposure for 700 hours in an atmosphere at a temperature of 80 ° C. and a relative humidity of 80% is achieved. Can be difficult. Utilizing the property that oxidative condensation of m-phenylenediamine does not easily proceed, it is possible to stably provide a phenylenediamine condensate in a void by adding a large amount of m-phenylenediamine to p-phenylenediamine. Become. However, oxidative condensation hardly proceeds with only m-phenylenediamine, which requires a very long time for the application treatment and lowers the productivity. Although a method of treating at a high temperature to promote oxidative condensation is also mentioned, it is not so preferable because the yarn strength may be reduced during the treatment.
[0021]
The chemical action of the basic organic compound inside the fiber is not clearly known. Simply, since the monomer or condensate of the basic organic compound is filled between the microvoids in the polybenzazole fiber, water vapor from outside reaches the PBZ molecules even when exposed to high temperature and high humidity for a long time. Is it difficult to reduce the strength, or the basic substance captures the hydrogen ions released by the dissociation of the mineral acid or its condensate remaining in the polybenzazole fiber due to moisture The strength is suppressed by reducing the strength, or the condensate of a basic organic compound with a long conjugate length captures radicals generated in the fiber for some reason and stabilizes the system. It is estimated that the decrease is suppressed, but the present invention is not limited to this consideration.
[0022]
The spun yarn made of the polybenzazole fiber thus obtained has a durability of 70% or more, preferably 75% or more after a 700-hour exposure in an atmosphere at a temperature of 80 ° C. and a relative humidity of 80%. It will be excellent. Furthermore, by using the spun yarn made of the obtained polybenzazole fiber, it is possible to obtain a protective material, protective clothing, and a fiber structure constituting an industrial material having excellent durability.
[0023]
The spun yarn that is the object of the present invention is a composite spun yarn blended with other fibers within the scope of the present invention. Other fibers are natural fibers, organic fibers, metal fibers, inorganic fibers, mineral fibers, and the like. Further, the blending method is not particularly limited, and may be a general blended cotton blended blend or one having a core-sheath structure.
[0024]
【Example】
Hereinafter, the present invention will be specifically described using actual examples, but the present invention is not limited to the following examples as a matter of course, and is carried out with appropriate changes within a range that can conform to the gist of the preceding and following paragraphs. It is, of course, possible, and all of them are included in the technical scope of the present invention.
[0025]
(Evaluation method of strength reduction under high temperature and high humidity)
The evaluation of the strength decrease under high temperature and high humidity is performed by storing the sample in a thermo-hygrostat at high temperature and high humidity, and then placing it in a standard condition (temperature: 20 ± 2 ° C, relative humidity 65 ± 2%) test chamber. The sample was taken out, a tensile test was performed within 30 minutes, and the strength before the treatment was evaluated based on the strength retention after the treatment. Humidic Chamber 1G43M manufactured by Yamato Scientific Co., Ltd. was used for the storage test under high temperature and high humidity, and the light was completely shielded from light in a constant temperature and humidity chamber at 80 ° C. and a relative humidity of 80%. For 700 hours.
[0026]
The strength retention is measured by measuring the tensile strength before and after storage at high temperature and high humidity, and measuring the tensile strength after storage test at high temperature and high humidity by using a tensile tester (Shimadzu Corporation, type AG-50KNG) according to JIS-L1015. Measured.
[0027]
(Evaluation method of residual phosphoric acid concentration and sodium concentration in fiber)
The residual phosphorus concentration in the fiber was measured by using a fluorescent X-ray measuring device (Philips PW1404 / DY685) after solidifying the sample into a pellet, and the sodium concentration was measured by a neutron activation analysis method.
[0028]
The water content was calculated from the weight before drying: W0 (g) and the weight after drying: W1 (g) according to the following formula. The drying was performed at 200 ° C. for 1 hour.
(Formula) Moisture percentage (%) = (W0−W1) / W1 × 100
[0029]
(Example 1)
A spin dope comprising 14% by weight of polyparaphenylene benzobisoxazole having an intrinsic viscosity of 30 dL / g and polyphosphoric acid having a phosphorus pentoxide content of 84.3% measured with a methanesulfonic acid solution at 30 ° C. at a spinning temperature of 175 ° C. After being extruded from a 0.18 mm nozzle having 166 holes to form a filament, it was immersed in a first cleaning bath arranged so as to be converged at an appropriate position to form a multifilament, and solidified. A quench chamber was installed in the air gap between the spinning nozzle and the first cleaning bath so that the filament was drawn at a more uniform temperature. The quench temperature was 60 ° C. Thereafter, the filament was washed with water until the concentration of residual phosphorus in the polybenzazole fiber became 5000 ppm or less, and the filament was wound around a paper tube without drying. The winding speed was 200 m / min, the spinning draw ratio was 40, and the winding amount of the filament was 1500 m. The filament thus wound had a single yarn fineness of 1.5 dpf (denier / filament), a diameter of 11.5 μm, and a water content of 50%.
The wound yarn was neutralized with a 1% aqueous solution of NaOH for 10 seconds, washed with water for 30 seconds, and wound on a porous resin bobbin without drying. The water content of the wound yarn was 50%. A solution obtained by dissolving 2.8 g of m-phenylenediamine and 1.2 g of p-phenylenediamine in 12 L of water is placed in the apparatus shown in FIG. 1, the wound yarn is placed therein, and the solution is left at room temperature (20 ° C.) for 24 hours. After the circulation, the liquid in the apparatus was further replaced with pure water and circulated at room temperature (20 ° C.) for 1 hour. Thereafter, the yarn was taken out of the device and dried at 80 ° C. for 4 hours. The circulation of the liquid was performed while supplying air into the liquid. As a result of measuring the residual phosphorus concentration and sodium concentration in the fiber of the obtained yarn, the phosphorus concentration was 1900 ppm, the sodium concentration was 760 ppm, and the Na / P molar ratio was 0.54. Subsequently, a staple fiber having a cut length of 51 mm was manufactured from the obtained polybenzasol fiber, the twist coefficient was set to 3.5, and a 20Ne spun yarn was manufactured with a cotton count. The tensile strength of the obtained spun yarn was 9.8 cN / dtex. The spun yarn thus obtained was subjected to a high-temperature and high-humidity storage test (80 ° C., 80 RH%), and as a result, the strength retention was 77%.
[0030]
(Comparative Example 1)
Washing was carried out with water until the residual phosphorus concentration in the polybenzazole fiber became 5,000 ppm or less, and drying was not carried out.
The wound yarn was neutralized with a 1% aqueous solution of NaOH for 10 seconds, washed with water for 30 seconds, and then dried at 80 ° C. for 4 hours. As a result of measuring the residual phosphorus concentration and sodium concentration in the fiber of the obtained yarn, the phosphorus concentration was 4700 ppm, the sodium concentration was 3300 ppm, and the molar ratio of Na / P was 0.95. A staple fiber having a cut length of 51 mm was manufactured from the obtained polybenzasol fiber, the twist coefficient was set to 3.5, and a 20Ne spun yarn was manufactured with a cotton count. The tensile strength of the obtained spun yarn was 9.1 cN / dtex. Subsequently, the obtained spun yarn was subjected to a high-temperature and high-humidity storage test (80 ° C., 80 RH%), and as a result, the strength retention was 60%.
[0031]
From the above results, it is understood that the spun yarn made of the polybenzazole fiber of the example has a very high strength retention after being exposed to high temperature and high humidity as compared with the comparative example.
[0032]
【The invention's effect】
According to the present invention, a polybenzazole fiber suitable for a fibrous structure such as a protective material, a protective garment, and an industrial material that can sufficiently maintain strength even when exposed to high temperature and high humidity for a long time. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an example of a cheese dyeing apparatus.
1: treatment layer, 2: treatment liquid, 3: yanked undried yarn, 4: porous bobbin having water permeability, 5: bobbin stopper, 6: treatment liquid circulation pump

Claims (3)

A spun yarn comprising at least a portion of a polybenzazole fiber having a tensile strength retention of 70% or more after being exposed to an atmosphere at a temperature of 80 ° C and a relative humidity of 80% for 700 hours. The spun yarn according to claim 1, wherein the polybenzazole fiber contains a basic organic compound in the form of a monomer or a condensate. The spun yarn according to claim 1, wherein the basic organic compound is p-phenylenediamine, m-phenylenediamine, or a mixture thereof.

Images